Science.gov

Sample records for aerosol layer heights

  1. Urban atmospheric boundary layer height by aerosol lidar and ceilometer

    NASA Astrophysics Data System (ADS)

    Choi, M. H.; Park, M. S.; Park, S. H.

    2014-12-01

    The characteristics of urban atmospheric boundary layer (ABL) height on January, April, July and October 2014 using the gradient method by a ceilometer with a wavelength of 910 nm and an aerosol lidar with a wavelength of 532 and 1064 nm installed at two urban sites (Gwanghwamun and Jungnang) in Korea are analyzed. The Gwanghwamun site located at urban commercial area is 10 km apart from the Jungnang site located at urban residential area. The ABL height is determined by a height with a strong gradient of vertical backscatter intensity. It is found that the ABL height at both sites show a similar pattern and has a strong diurnal variation with a steep increase at 09-12 KST with a maximum in the late afternoon. And it is not determined clearly and the correlation between the ABL height by a ceilometer and that by an aerosol lidar is relatively low in case of high PM10 concentration such as Asian dust, haze and smog. Uncertainty of ABL height is also found to be strongly affected by the weather phenomena such as rain, haze or fog.

  2. Mixing-Height Time Series from Operational Ceilometer Aerosol-Layer Heights

    NASA Astrophysics Data System (ADS)

    Lotteraner, Christoph; Piringer, Martin

    2016-07-01

    A new method is described to derive mixing-height time series directly from aerosol-layer height data available from a Vaisala CL51 ceilometer. As complete as possible mixing-height time series are calculated by avoiding outliers, filling data gaps by linear interpolation, and smoothing. In addition, large aerosol-layer heights at night that can be interpreted as residual layers are not assigned as mixing heights. The resulting mixing-height time series, converted to an appropriate data format, can be used as input for dispersion calculations. Two case examples demonstrate in detail how the method works. The mixing heights calculated using ceilometer data are compared with values determined from radiosounding data at Vienna by applying the parcel, Heffter, and Richardson methods. The results of the parcel method, obtained from radiosonde profiles at noon, show the best fit to the ceilometer-derived mixing heights. For midnight radiosoundings, larger deviations between mixing heights from the ceilometer and those deduced from the potential temperature profiles of the soundings are found. We use data from two Vaisala CL51 ceilometers, operating in the Vienna area at an urban and rural site, respectively, during an overlapping period of about 1 year. In addition to the case studies, the calculated mixing-height time series are also statistically evaluated and compared, demonstrating that the ceilometer-based mixing height follows an expected daily and seasonal course.

  3. Vertical aerosol structure and aerosol mixed layer heights determined with scanning shipborne lidars during the TexAQS II study

    NASA Astrophysics Data System (ADS)

    McCarty, B. J.; Senff, C. J.; Tucker, S. C.; Eberhard, W. L.; Marchbanks, R. D.; Machol, J.; Brewer, W. A.

    2007-12-01

    The NOAA Earth Systems Research Laboratory (ESRL) deployed the Ozone Profiling Atmospheric LIDAR (OPAL) on the R/V Ronald H. Brown during the summer of 2006 for the Texas Air Quality Study (TEXAQS II). Calibrated aerosol backscatter profiles were determined from data collected at the 355 nm wavelength using a modified Klett retrieval method. OPAL employs a unique scan sequence that consists of staring at multiple elevation angles between 2 and 90 degrees, which is repeated approx. every 90 sec. Blending the data from the various elevation angles allows to extend the aerosol backscatter profiles down to near the surface (approximately 10 meters ASL), while maintaining a high spatial resolution (5 meters). Successful application of this technique requires the aerosol distribution to be sufficiently horizontally homogeneous over several kilometers. Estimates of aerosol mixed layer height were determined by applying a Haar wavelet transform method to detect the gradient that is often present at the top of the boundary layer. Co-located on the R/V Ronald H. Brown, was NOAA/ESRL's High Resolution Doppler LIDAR (HRDL). Aerosol mixed layer heights were also estimated using the data from the 2 micron Doppler LIDAR. A comparison of the mixed layer heights as determined from each LIDAR's observations was used to choose the height of the layer likely connected with the surface. The vertical structure of aerosols in the lower troposphere, in particular the presence of aerosol layers above the boundary layer, is important in understanding radiative effects of aerosols. We will present aerosol backscatter structure in the lower troposphere encountered during the TexAQS II study as well as a comparison of relative aerosol content in the free troposphere compared to that within the boundary layer.

  4. Developments in the Aerosol Layer Height Retrieval Algorithm for the Copernicus Sentinel-4/UVN Instrument

    NASA Astrophysics Data System (ADS)

    Nanda, Swadhin; Sanders, Abram; Veefkind, Pepijn

    2016-04-01

    The Sentinel-4 mission is a part of the European Commission's Copernicus programme, the goal of which is to provide geo-information to manage environmental assets, and to observe, understand and mitigate the effects of the changing climate. The Sentinel-4/UVN instrument design is motivated by the need to monitor trace gas concentrations and aerosols in the atmosphere from a geostationary orbit. The on-board instrument is a high resolution UV-VIS-NIR (UVN) spectrometer system that provides hourly radiance measurements over Europe and northern Africa with a spatial sampling of 8 km. The main application area of Sentinel-4/UVN is air quality. One of the data products that is being developed for Sentinel-4/UVN is the Aerosol Layer Height (ALH). The goal is to determine the height of aerosol plumes with a resolution of better than 0.5 - 1 km. The ALH product thus targets aerosol layers in the free troposphere, such as desert dust, volcanic ash and biomass during plumes. KNMI is assigned with the development of the Aerosol Layer Height (ALH) algorithm. Its heritage is the ALH algorithm developed by Sanders and De Haan (ATBD, 2016) for the TROPOMI instrument on board the Sentinel-5 Precursor mission that is to be launched in June or July 2016 (tentative date). The retrieval algorithm designed so far for the aerosol height product is based on the absorption characteristics of the oxygen-A band (759-770 nm). The algorithm has heritage to the ALH algorithm developed for TROPOMI on the Sentinel 5 precursor satellite. New aspects for Sentinel-4/UVN include the higher resolution (0.116 nm compared to 0.4 for TROPOMI) and hourly observation from the geostationary orbit. The algorithm uses optimal estimation to obtain a spectral fit of the reflectance across absorption band, while assuming a single uniform layer with fixed width to represent the aerosol vertical distribution. The state vector includes amongst other elements the height of this layer and its aerosol optical

  5. Aerosol black carbon characteristics over Central India: Temporal variation and its dependence on mixed layer height

    NASA Astrophysics Data System (ADS)

    Kompalli, Sobhan Kumar; Babu, S. Suresh; Moorthy, K. Krishna; Manoj, M. R.; Kumar, N. V. P. Kiran; Shaeb, K. Hareef Baba; Joshi, Ashok Kumar

    2014-10-01

    In a first of its kind study over the Indian region, concurrent and extensive measurements of black carbon (BC) concentration and atmospheric boundary layer parameters are used to quantify the role of atmospheric boundary layer in producing temporal changes in BC. During this study, 18 months (2011-12) data of continuous measurements of BC aerosols, made over a semi-urban location, Nagpur, in Central India are used along with concurrent measurements of vertical profiles of atmospheric thermodynamics, made using weekly ascents of GPS aided Radiosonde for a period of 1 year. From the balloon data, mixed layer heights and ventilation coefficients are estimated, and the monthly and seasonal changes in BC mass concentration are examined in the light of the boundary layer changes. Seasonally, the BC mass concentration was highest (~ 4573 ± 1293 ng m- 3) in winter (December-February), and lowest (~ 1588 ± 897 ng m- 3) in monsoon (June-September), while remained moderate (~ 3137 ± 1446 ng m- 3) in pre-monsoon (March-May), and post-monsoon (~ 3634 ± 813 ng m- 3) (October-November) seasons. During the dry seasons, when the rainfall is scanty or insignificantly small, the seasonal variations in BC concentrations have a strong inverse relationship with mixed layer height and ventilation coefficient. However, the lowest BC concentrations do not occur during the season when the mixed layer height (MLH) is highest or the ventilation coefficient is the highest; rather it occurs when the rainfall is strong (during summer monsoon season) and airmass changes to primarily of marine origin.

  6. Height Distribution Between Cloud and Aerosol Layers from the GLAS Spaceborne Lidar in the Indian Ocean Region

    NASA Technical Reports Server (NTRS)

    Hart, William D.; Spinhirne, James D.; Palm, Steven P.; Hlavka, Dennis L.

    2005-01-01

    The Geoscience Laser Altimeter System (GLAS), a nadir pointing lidar on the Ice Cloud and land Elevation Satellite (ICESat) launched in 2003, now provides important new global measurements of the relationship between the height distribution of cloud and aerosol layers. GLAS data have the capability to detect, locate, and distinguish between cloud and aerosol layers in the atmosphere up to 40 km altitude. The data product algorithm tests the product of the maximum attenuated backscatter coefficient b'(r) and the vertical gradient of b'(r) within a layer against a predetermined threshold. An initial case result for the critical Indian Ocean region is presented. From the results the relative height distribution between collocated aerosol and cloud shows extensive regions where cloud formation is well within dense aerosol scattering layers at the surface. Citation: Hart, W. D., J. D. Spinhime, S. P. Palm, and D. L. Hlavka (2005), Height distribution between cloud and aerosol layers from the GLAS spaceborne lidar in the Indian Ocean region,

  7. Utilization of O4 Slant Column Density to Derive Aerosol Layer Height from a Space-Borne UV-Visible Hyperspectral Sensor: Sensitivity and Case Study

    NASA Technical Reports Server (NTRS)

    Park, Sang Seo; Kim, Jhoon; Lee, Hanlim; Torres, Omar; Lee, Kwang-Mog; Lee, Sang Deok

    2016-01-01

    The sensitivities of oxygen-dimer (O4) slant column densities (SCDs) to changes in aerosol layer height are investigated using the simulated radiances by a radiative transfer model, the linearized pseudo-spherical vector discrete ordinate radiative transfer (VLIDORT), and the differential optical absorption spectroscopy (DOAS) technique. The sensitivities of the O4 index (O4I), which is defined as dividing O4 SCD by 10(sup 40) molecules (sup 2) per centimeters(sup -5), to aerosol types and optical properties are also evaluated and compared. Among the O4 absorption bands at 340, 360, 380, and 477 nanometers, the O4 absorption band at 477 nanometers is found to be the most suitable to retrieve the aerosol effective height. However, the O4I at 477 nanometers is significantly influenced not only by the aerosol layer effective height but also by aerosol vertical profiles, optical properties including single scattering albedo (SSA), aerosol optical depth (AOD), particle size, and surface albedo. Overall, the error of the retrieved aerosol effective height is estimated to be 1276, 846, and 739 meters for dust, non-absorbing, and absorbing aerosol, respectively, assuming knowledge on the aerosol vertical distribution shape. Using radiance data from the Ozone Monitoring Instrument (OMI), a new algorithm is developed to derive the aerosol effective height over East Asia after the determination of the aerosol type and AOD from the MODerate resolution Imaging Spectroradiometer (MODIS). About 80 percent of retrieved aerosol effective heights are within the error range of 1 kilometer compared to those obtained from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements on thick aerosol layer cases.

  8. Utilization of O4 slant column density to derive aerosol layer height from a space-borne UV-visible hyperspectral sensor: sensitivity and case study

    NASA Astrophysics Data System (ADS)

    Park, Sang Seo; Kim, Jhoon; Lee, Hanlim; Torres, Omar; Lee, Kwang-Mog; Lee, Sang Deok

    2016-02-01

    The sensitivities of oxygen-dimer (O4) slant column densities (SCDs) to changes in aerosol layer height are investigated using the simulated radiances by a radiative transfer model, the linearized pseudo-spherical vector discrete ordinate radiative transfer (VLIDORT), and the differential optical absorption spectroscopy (DOAS) technique. The sensitivities of the O4 index (O4I), which is defined as dividing O4 SCD by 1040 molecules2 cm-5, to aerosol types and optical properties are also evaluated and compared. Among the O4 absorption bands at 340, 360, 380, and 477 nm, the O4 absorption band at 477 nm is found to be the most suitable to retrieve the aerosol effective height. However, the O4I at 477 nm is significantly influenced not only by the aerosol layer effective height but also by aerosol vertical profiles, optical properties including single scattering albedo (SSA), aerosol optical depth (AOD), particle size, and surface albedo. Overall, the error of the retrieved aerosol effective height is estimated to be 1276, 846, and 739 m for dust, non-absorbing, and absorbing aerosol, respectively, assuming knowledge on the aerosol vertical distribution shape. Using radiance data from the Ozone Monitoring Instrument (OMI), a new algorithm is developed to derive the aerosol effective height over East Asia after the determination of the aerosol type and AOD from the MODerate resolution Imaging Spectroradiometer (MODIS). About 80 % of retrieved aerosol effective heights are within the error range of 1 km compared to those obtained from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements on thick aerosol layer cases.

  9. Retrieval of Aerosol Height with TROPOMI

    NASA Astrophysics Data System (ADS)

    Sanders, A. F. J.; de Haan, J. F.; Veefkind, J. P.

    2012-04-01

    The Tropospheric Monitoring Instrument (TROPOMI), to be launched in 2015, will feature a new aerosol product providing the height of aerosol layers. Aerosol Layer Height will be one of two aerosol products, the other one being the Absorbing Aerosol Index. TROPOMI is a UV-VIS-NIR imaging spectrometer with daily global coverage. It will be part of ESA's Sentinel-5 Precursor mission. Algorithm development for the aerosol height product is currently underway at KNMI. In this presentation we will introduce the algorithm, highlight some of the development issues and discuss possible applications and example aerosol cases. Aerosol height observations from the near-infrared wavelength range will improve retrieval of other aerosol properties, particularly retrieval of absorption optical thickness. An increase in absorption in the ultraviolet wavelength range can be due to a higher imaginary part of the refractive index or to the aerosol layer being at a higher altitude. Independent height observations will therefore further constrain retrieval of the single scattering albedo. Furthermore, aerosol profile information is an important parameter when estimating radiative forcings and climate impacts of aerosol, it is a significant source of uncertainty in trace gas retrieval and it helps in understanding atmospheric transport mechanisms. Finally, timely available, global observations of aerosol height will be of interest to aviation safety agencies. The retrieval algorithm for aerosol height will be based on absorption by oxygen in the A-band (759-770 nm). Aerosols are assumed to be contained in a single layer. A spectral fit of reflectance (resolution 0.5 nm) across the absorption band provides layer height. The retrieval method will be optimal estimation to ensure a proper error analysis. Sensitivity studies have indicated that accuracy and precision of retrieved height for cloud-free scenes will be well below the TROPOMI science requirements (1 km). They have also shown that

  10. Airborne Lidar measurements of aerosols, mixed layer heights, and ozone during the 1980 PEPE/NEROS summer field experiment

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Shipley, S. T.; Butler, C. F.; Ismail, S.

    1985-01-01

    A detailed summary of the NASA Ultraviolet Differential Absorption Lidar (UV DIAL) data archive obtained during the EPA Persistent Elevated Pollution Episode/Northeast Regional Oxidant Study (PEPE/NEROS) Summer Field Experiment Program (July through August 1980) is presented. The UV dial data set consists of remote measurements of mixed layer heights, aerosol backscatter cross sections, and sequential ozone profiles taken during 14 long-range flights onboard the NASA Wallops Flight Center Electra aircraft. These data are presented in graphic and tabular form, and they have been submitted to the PEPE/NEROS data archive on digital magnetic tape. The derivation of mixing heights and ozone profiles from UV Dial signals is discussed, and detailed intercomparisons with measurements obtained by in situ sensors are presented.

  11. Evaluation of the operational Aerosol Layer Height retrieval algorithm for Sentinel-5 Precursor: application to O2 A band observations from GOME-2A

    NASA Astrophysics Data System (ADS)

    Sanders, A. F. J.; de Haan, J. F.; Sneep, M.; Apituley, A.; Stammes, P.; Vieitez, M. O.; Tilstra, L. G.; Tuinder, O. N. E.; Koning, C. E.; Veefkind, J. P.

    2015-06-01

    An algorithm setup for the operational Aerosol Layer Height product for TROPOMI on the Sentinel-5 Precursor mission is described and discussed, applied to GOME-2A data, and evaluated with lidar measurements. The algorithm makes a spectral fit of reflectance at the O2 A band in the near-infrared and the fit window runs from 758 to 770 nm. The aerosol profile is parameterized by a scattering layer with constant aerosol volume extinction coefficient and aerosol single scattering albedo and with a fixed pressure thickness. The algorithm's target parameter is the height of this layer. In this paper, we apply the algorithm to observations from GOME-2A in a number of systematic and extensive case studies and we compare retrieved aerosol layer heights with lidar measurements. Aerosol scenes cover various aerosol types, both elevated and boundary layer aerosols, and land and sea surfaces. The aerosol optical thicknesses for these scenes are relatively moderate. Retrieval experiments with GOME-2A spectra are used to investigate various sensitivities, in which particular attention is given to the role of the surface albedo. From retrieval simulations with the single-layer model, we learn that the surface albedo should be a fit parameter when retrieving aerosol layer height from the O2 A band. Current uncertainties in surface albedo climatologies cause biases and non-convergences when the surface albedo is fixed in the retrieval. Biases disappear and convergence improves when the surface albedo is fitted, while precision of retrieved aerosol layer pressure is still largely within requirement levels. Moreover, we show that fitting the surface albedo helps to ameliorate biases in retrieved aerosol layer height when the assumed aerosol model is inaccurate. Subsequent retrievals with GOME-2A spectra confirm that convergence is better when the surface albedo is retrieved simultaneously with aerosol parameters. However, retrieved aerosol layer pressures are systematically low (i

  12. Evaluation of the operational Aerosol Layer Height retrieval algorithm for Sentinel-5 Precursor: application to O2 A band observations from GOME-2A

    NASA Astrophysics Data System (ADS)

    Sanders, A. F. J.; de Haan, J. F.; Sneep, M.; Apituley, A.; Stammes, P.; Vieitez, M. O.; Tilstra, L. G.; Tuinder, O. N. E.; Koning, C. E.; Veefkind, J. P.

    2015-11-01

    An algorithm setup for the operational Aerosol Layer Height product for TROPOMI on the Sentinel-5 Precursor mission is described and discussed, applied to GOME-2A data, and evaluated with lidar measurements. The algorithm makes a spectral fit of reflectance at the O2 A band in the near-infrared and the fit window runs from 758 to 770 nm. The aerosol profile is parameterised by a scattering layer with constant aerosol volume extinction coefficient and aerosol single scattering albedo and with a fixed pressure thickness. The algorithm's target parameter is the height of this layer. In this paper, we apply the algorithm to observations from GOME-2A in a number of systematic and extensive case studies, and we compare retrieved aerosol layer heights with lidar measurements. Aerosol scenes cover various aerosol types, both elevated and boundary layer aerosols, and land and sea surfaces. The aerosol optical thicknesses for these scenes are relatively moderate. Retrieval experiments with GOME-2A spectra are used to investigate various sensitivities, in which particular attention is given to the role of the surface albedo. From retrieval simulations with the single-layer model, we learn that the surface albedo should be a fit parameter when retrieving aerosol layer height from the O2 A band. Current uncertainties in surface albedo climatologies cause biases and non-convergences when the surface albedo is fixed in the retrieval. Biases disappear and convergence improves when the surface albedo is fitted, while precision of retrieved aerosol layer pressure is still largely within requirement levels. Moreover, we show that fitting the surface albedo helps to ameliorate biases in retrieved aerosol layer height when the assumed aerosol model is inaccurate. Subsequent retrievals with GOME-2A spectra confirm that convergence is better when the surface albedo is retrieved simultaneously with aerosol parameters. However, retrieved aerosol layer pressures are systematically low (i

  13. The role of cloud contamination, aerosol layer height and aerosol model in the assessment of the OMI near-UV retrievals over the ocean

    NASA Astrophysics Data System (ADS)

    Gassó, Santiago; Torres, Omar

    2016-07-01

    Retrievals of aerosol optical depth (AOD) at 388 nm over the ocean from the Ozone Monitoring Instrument (OMI) two-channel near-UV algorithm (OMAERUV) have been compared with independent AOD measurements. The analysis was carried out over the open ocean (OMI and MODerate-resolution Imaging Spectrometer (MODIS) AOD comparisons) and over coastal and island sites (OMI and AERONET, the AErosol RObotic NETwork). Additionally, a research version of the retrieval algorithm (using MODIS and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) information as constraints) was utilized to evaluate the sensitivity of the retrieval to different assumed aerosol properties. Overall, the comparison resulted in differences (OMI minus independent measurements) within the expected levels of uncertainty for the OMI AOD retrievals (0.1 for AOD < 0.3, 30 % for AOD > 0.3). Using examples from case studies with outliers, the reasons that led to the observed differences were examined with specific purpose to determine whether they are related to instrument limitations (i.e., pixel size, calibration) or algorithm assumptions (such as aerosol shape, aerosol height). The analysis confirms that OMAERUV does an adequate job at rejecting cloudy scenes within the instrument's capabilities. There is a residual cloud contamination in OMI pixels with quality flag 0 (the best conditions for aerosol retrieval according to the algorithm), resulting in a bias towards high AODs in OMAERUV. This bias is more pronounced at low concentrations of absorbing aerosols (AOD 388 nm ˜ < 0.5). For higher aerosol loadings, the bias remains within OMI's AOD uncertainties. In pixels where OMAERUV assigned a dust aerosol model, a fraction of them (< 20 %) had retrieved AODs significantly lower than AERONET and MODIS AODs. In a case study, a detailed examination of the aerosol height from CALIOP and the AODs from MODIS, along with sensitivity tests, was carried out by varying the different assumed parameters in the

  14. Assessing Aerosol Mixed Layer Heights from the NASA Larc Airborne High Spectral Resolution Lidar (HSRL) during the Discover-AQ Field Campaigns

    NASA Astrophysics Data System (ADS)

    Scarino, A. J.; Ferrare, R. A.; Burton, S. P.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Berkoff, T.; Sawamura, P.; Collins, J. E., Jr.; Seaman, S. T.; Cook, A. L.; Harper, D. B.; Follette-Cook, M. B.; daSilva, A.; Randles, C. A.

    2014-12-01

    The first- and second-generation NASA airborne High Spectral Resolution Lidars (HSRL-1 and HSRL-2) have been deployed on board the NASA Langley Research Center King Air aircraft during the Deriving Information on Surface Conditions from Column and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaigns. These included deployments during July 2011 over Washington, D.C. and Baltimore, MD, during January and February 2013 over the San Joaquin Valley of California, during September 2013 over Houston, TX and during July and August 2014 over Denver, CO. Measurements of aerosol extinction, backscatter, and depolarization are available from both HSRL-1 and HSRL-2 in coordination with other participating research aircraft and ground sites. These measurements constitute a diverse data set for use in characterizing the spatial and temporal distribution of aerosols, aerosol optical thickness (AOT), as well as the mixed layer (ML) height. Analysis of the ML height at these four locations is presented, including temporal and horizontal variability and comparisons between land and water, including the Chesapeake Bay and Galveston Bay. Using the ML heights, the distribution of AOT relative to the ML heights is determined, which is relevant for assessing the long-range transport of aerosols. The ML heights are also used to help relate column AOT measurements and extinction profiles to surface PM2.5 concentrations. The HSRL ML heights are also used to evaluate the performance in simulating the temporal and spatial variability of ML heights from both chemical regional models and global forecast models.

  15. Raman Lidar Retrievals of Mixed Layer Heights

    NASA Astrophysics Data System (ADS)

    Ferrare, R. A.; Clayton, M.; Turner, D. D.; Newsom, R. K.; Goldsmith, J.

    2012-12-01

    Accurate determination of the atmospheric mixing layer (ML) height is important for modeling the transport of aerosols and aerosol precursors and forecasting air quality. Aerosol and water vapor profiles measured by the DOE ARM SGP and the new TWP (Darwin) ground based Raman lidars provide direct measurements of the vertical structure of ML. We have developed automated algorithms to identify sharp gradients in aerosols and water vapor at the top of the ML and have used these algorithms to derive ML heights for extended periods over the last few years. During the afternoon, these ML heights generally compare favorably with ML heights derived from potential temperature profiles derived from coincident radiosondes. However, retrieving ML heights via lidar measurements of water vapor and aerosol gradients is problematic in the presence of elevated aerosol and water vapor layers which are often observed, especially at night. Consequently, we take advantage of recent modifications to these lidars that permit continuous temperature profiling, and compute ML heights using potential temperature profiles derived from Raman lidar and Atmospheric Emitted Radiance Interferometer (AERI) measurements. The resulting ML heights agree well with ML heights derived from radiosondes and provide a more realistic representation of the diurnal ML behavior. We use the Raman lidar aerosol and water vapor profiles and ML heights to derive the fractions of total column precipitable water vapor and aerosol optical thickness within and above the ML and show how the ML heights and these fractions vary with time of day and season. The SGP Raman lidar measurements show that the fraction of the aerosol optical thickness and precipitable water vapor above the ML increases from 30-60% during the day to 60-80% at night. The Darwin Raman lidar measurements reveal a shallow, moist cloud-topped ML with little diurnal variability during the austral summer and deeper ML with more diurnal variability during

  16. Boundary Layer Heights from CALIOP

    NASA Astrophysics Data System (ADS)

    Kuehn, R.; Ackerman, S. A.; Holz, R.; Roubert, L.

    2012-12-01

    This work is focused on the development of a planetary boundary layer (PBL) height retrieval algorithm for CALIOP and validation studies. Our current approach uses a wavelet covariance transform analysis technique to find the top of the boundary layer. We use the methodology similar to that found in Davis et. al. 2000, ours has been developed to work with the lower SNR data provided by CALIOP, and is intended to work autonomously. Concurrently developed with the CALIOP algorithm we will show results from a PBL height retrieval algorithm from profiles of potential temperature, these are derived from Aircraft Meteorological DAta Relay (AMDAR) observations. Results from 5 years of collocated AMDAR - CALIOP retrievals near O'Hare airport demonstrate good agreement between the CALIOP - AMDAR retrievals. In addition, because we are able to make daily retrievals from the AMDAR measurements, we are able to observe the seasonal and annual variation in the PBL height at airports that have sufficient instrumented-aircraft traffic. Also, a comparison has been done between the CALIOP retrievals and the NASA Langley airborne High Spectral Resolution Lidar (HSRL) PBL height retrievals acquired during the GoMACCS experiment. Results of this comparison, like the AMDAR comparison are favorable. Our current work also involves the analysis and verification of the CALIOP PBL height retrieval from the 6 year CALIOP global data set. Results from this analysis will also be presented.

  17. Retrieving the Height of Smoke and Dust Aerosols by Synergistic Use of Multiple Satellite Sensors

    NASA Technical Reports Server (NTRS)

    Lee, Jaehwa; Hsu, N. Christina; Bettenhausen, Corey; Sayer, Andrew M.; Seftor, Colin J.; Jeong, Myeong-Jae

    2016-01-01

    The Aerosol Single scattering albedo and Height Estimation (ASHE) algorithm was first introduced in Jeong and Hsu (2008) to provide aerosol layer height and single scattering albedo (SSA) for biomass burning smoke aerosols. By using multiple satellite sensors synergistically, ASHE can provide the height information over much broader areas than lidar observations alone. The complete ASHE algorithm uses aerosol data from MODIS or VIIRS, OMI or OMPS, and CALIOP. A simplified algorithm also exists that does not require CALIOP data as long as the SSA of the aerosol layer is provided by another source. Several updates have recently been made: inclusion of dust layers in the retrieval process, better determination of the input aerosol layer height from CALIOP, improvement in aerosol optical depth (AOD) for nonspherical dust, development of quality assurance (QA) procedure, etc.

  18. Variability of aerosol properties and Planetary Boundary Layer heights from airborne High Spectral Resolution Lidar, ground-based measurements, and the WRF model during CalNex and CARES

    NASA Astrophysics Data System (ADS)

    Obland, M. D.; Swanson, A. J.; Ferrare, R. A.; Burton, S. P.; Hair, J. W.; Hostetler, C. A.; Rogers, R.; Fast, J. D.; Berg, L. K.; Pekour, M. S.; Shaw, W. J.; Zaveri, R. A.; Haman, C. L.; Cook, A.; Harper, D.

    2011-12-01

    The NASA airborne High Spectral Resolution Lidar (HSRL) was deployed on board the NASA Langley Research Center's B200 aircraft to California in May and June of 2010 to aid in characterizing aerosol properties during the CalNex and CARES field missions. Measurements of aerosol extinction (at 532 nm), backscatter (at 532 and 1064 nm), and depolarization (at 532 and 1064 nm) during 31 flights and nearly 100 hours, many in coordination with other participating research aircraft, satellites, and ground sites, constitute a diverse data set for use in characterizing the spatial and temporal distribution of aerosols, as well as properties and variability of the Planetary Boundary Layer (PBL). This work examines the variability of the extensive (dependent on aerosol type and number density) and intensive (dependent on aerosol type only) aerosol properties to aid in describing the broader context of aerosol behavior within and nearby the Sacramento and Los Angeles Basin regions. PBL heights derived from HSRL measurements will be compared with those produced by local ceilometers, radiosondes, and the Weather Research and Forecasting (WRF) model. Spatial and temporal averages of aerosol properties will be presented.

  19. Determining Aerosol Plume Height from Two GEO Imagers: Lessons from MISR and GOES

    NASA Technical Reports Server (NTRS)

    Wu, Dong L.

    2012-01-01

    Aerosol plume height is a key parameter to determine impacts of particulate matters generated from biomass burning, wind-blowing dust, and volcano eruption. Retrieving cloud top height from stereo imageries from two GOES (Geostationary Operational Environmental Satellites) have been demonstrated since 1970's and the principle should work for aerosol plumes if they are optically thick. The stereo technique has also been used by MISR (Multiangle Imaging SpectroRadiometer) since 2000 that has nine look angles along track to provide aerosol height measurements. Knowing the height of volcano aerosol layers is as important as tracking the ash plume flow for aviation safety. Lack of knowledge about ash plume height during the 2010 Eyja'rjallajokull eruption resulted in the largest air-traffic shutdown in Europe since World War II. We will discuss potential applications of Asian GEO satellites to make stereo measurements for dust and volcano plumes.

  20. Global Distribution of Planetary Boundary Layer Height Derived from CALIPSO

    NASA Astrophysics Data System (ADS)

    Huang, J.

    2015-12-01

    The global distribution of planetary boundary layer (PBL) height, which was estimated from the attenuated back-scatter observations of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), is presented. In general, the PBL is capped by a temperature inversion that tends to trap moisture and aerosols. The gradient of back-scatter observed by lidar is almost always associated with this temperature inversion and the simultaneous decrease of moisture content. Thus, the PBL top is defined as the location of the maximum aerosol scattering gradient, which is analogous to the more conventional thermodynamic definition. The maximum standard deviation method, developed by Jordan et al. (2010), is modified and used to derive the global PBL heights. The derived PBL heights are not only consistent with the results of McGrath-Spangler and Denning (2012) but also agree well with the ground-based lidar measurements. It is found that the correlation between CALIPSO and the ground-based lidar was 0.73. The seasonal mean patterns from 4-year mid-day PBL heights over global are demonstrated. Also it is found that the largest PBL heights occur over the Tibetan Plateau and the coastal areas. The smallest PBL heights appear in the Tarim Basin and the northeast of China during the local winter. The comparison of PBL heights from CALIPSO and ECMWF under different land-cover conditions showed that, over ocean and forest surface, the PBL height estimated from the CALIPSO back-scatter climatology is larger than the ones estimated from ECMWF data. However, the PBL heights from ECMWF, over grass land and bare land surface in spring and summer are larger than the ones from CALIPSO.

  1. Retrieving the Height of Smoke and Dust Aerosols by Synergistic Use of VIIRS, OMPS, and CALIOP Observations

    NASA Technical Reports Server (NTRS)

    Lee, Jaehwa; Hsu, N. Christina; Bettenhausen, Corey; Sayer, Andrew M.; Seftor, Colin J.; Jeong, Myeong-Jae

    2015-01-01

    Aerosol Single scattering albedo and Height Estimation (ASHE) algorithm was first introduced in Jeong and Hsu (2008) to provide aerosol layer height as well as single scattering albedo (SSA) for biomass burning smoke aerosols. One of the advantages of this algorithm was that the aerosol layer height can be retrieved over broad areas, which had not been available from lidar observations only. The algorithm utilized aerosol properties from three different satellite sensors, i.e., aerosol optical depth (AOD) and Ångström exponent (AE) from Moderate Resolution Imaging Spectroradiometer (MODIS), UV aerosol index (UVAI) from Ozone Monitoring Instrument (OMI), and aerosol layer height from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). Here, we extend the application of the algorithm to Visible Infrared Imaging Radiometer Suite (VIIRS) and Ozone Mapping and Profiler Suite (OMPS) data. We also now include dust layers as well as smoke. Other updates include improvements in retrieving the AOD of nonspherical dust from VIIRS, better determination of the aerosol layer height from CALIOP, and more realistic input aerosol profiles in the forward model for better accuracy.

  2. BOREAS AFM-6 Boundary Layer Height Data

    NASA Technical Reports Server (NTRS)

    Wilczak, James; Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology (AFM)-6 team from National Oceanic and Atmospheric Adminsitration/Environment Technology Laboratory (NOAA/ETL) operated a 915-MHz wind/Radio Acoustic Sounding System (RASS) profiler system in the Southern Study Area (SSA) near the Old Jack Pine (OJP) site. This data set provides boundary layer height information over the site. The data were collected from 21 May 1994 to 20 Sep 1994 and are stored in tabular ASCII files. The boundary layer height data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  3. CALIPSO inferred most probable heights of global dust and smoke layers

    NASA Astrophysics Data System (ADS)

    Huang, Jingfeng; Guo, Jianping; Wang, Fu; Liu, Zhaoyan; Jeong, Myeong-Jae; Yu, Hongbin; Zhang, Zhibo

    2015-05-01

    The vertical location of aerosol layers is critical for determining predominance of aerosol radiative and microphysical effects in aerosol-cloud-precipitation-climate interaction. The spaceborne lidar system, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), provides an unprecedented opportunity to observe vertical distributions of global aerosol layers. In this study we examine the most probable height (MPH) of dust and smoke layers, which are calculated either from aerosol occurrence frequency (OF) in vertical feature mask or aerosol extinction profile. The study focuses on six high-aerosol-loading regions where aerosols are of great interest in a range of scientific topics: Saharan Air Layer (SAL) over Tropical Atlantic, West African Monsoon region (WAM), Southeast Atlantic Ocean (SAO), Southeast Asia (SEA) and South China Sea, Amazon (AMZ), and Northwestern Pacific (NWP). The analysis revealed interesting spatial and seasonal variability of different vertical mixture features over these regions: seasonal migration of dust layers over SAL, separation and mixture of dust and smoke layers over WAM and NWP, and smoke layer above clouds over SAO, SEA, and AMZ. Results also indicated that the OF-based MPH tends to be much higher than the aerosol optical depth (AOD)-based MPH, owing to the predominating near-surface sources. Within the same vertical resolution grid of CALIPSO, aerosols are found with higher OF at higher levels but AOD tends to increase toward lower levels, because most aerosol sources are near the surface and the aerosol layers transported to high altitudes are generally much more diluted over larger spatial domain than those near the surface.

  4. Retrieving the height of smoke and dust aerosols by synergistic use of VIIRS, OMPS, and CALIOP observations

    NASA Astrophysics Data System (ADS)

    Lee, Jaehwa; Hsu, N. Christina; Bettenhausen, Corey; Sayer, Andrew M.; Seftor, Colin J.; Jeong, Myeong-Jae

    2015-08-01

    This study extends the application of the previously developed Aerosol Single-scattering albedo and layer Height Estimation (ASHE) algorithm, which was originally applied to smoke aerosols only, to both smoke and dust aerosols by including nonspherical dust properties in the retrieval process. The main purpose of the algorithm is to derive aerosol height information over wide areas using aerosol products from multiple satellite sensors simultaneously: aerosol optical depth (AOD) and Ångström exponent from the Visible Infrared Imaging Radiometer Suite (VIIRS), UV aerosol index from the Ozone Mapping and Profiler Suite (OMPS), and total backscatter coefficient profile from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). The case studies suggest that the ASHE algorithm performs well for both smoke and dust aerosols, showing root-mean-square error of the retrieved aerosol height as compared to CALIOP observations from 0.58 to 1.31 km and mean bias from -0.70 to 1.13 km. In addition, the algorithm shows the ability to retrieve single-scattering albedo to within 0.03 of Aerosol Robotic Network inversion data for moderate to thick aerosol loadings (AOD of ~1.0). For typical single-layered aerosol cases, the estimated uncertainty in the retrieved height ranges from 1.20 to 1.80 km over land and from 1.15 to 1.58 km over ocean when favorable conditions are met. Larger errors are observed for multilayered aerosol events, due to the limited sensitivities of the passive sensors to such cases.

  5. Vegetation fires in the himalayan region - Aerosol load, black carbon emissions and smoke plume heights

    NASA Astrophysics Data System (ADS)

    Vadrevu, Krishna Prasad; Ellicott, Evan; Giglio, Louis; Badarinath, K. V. S.; Vermote, Eric; Justice, Chris; Lau, William K. M.

    2012-02-01

    In this study, we investigate the potential of multi-satellite datasets for quantifying the biomass burning emissions from the Himalayan region. A variety of satellite products were used for characterizing fire events including active fire counts, burnt areas, aerosol optical depth (AOD) variations, aerosol index and smoke plume heights. Results from the MODerate-resolution Imaging Spectroradiometer (MODIS) fire product suggest March-June as the major fire season with the peak during the April. An average of 3908 fire counts per year were recorded with sixty four percent of the fires occurring in the low elevation areas in the Himalayan Region. We estimate average burnt areas of 1129 sq. km, with the black carbon emissions of 431 Mg, per year. The mean AOD (2005-2010) was 0.287 ± 0.105 (one sigma) with peak values in May. Correlation analysis between the fire counts and AOD resulted in a Pearson correlation coefficient of 0.553; the correlation between the FRP and AOD is relatively weaker ( r = 0.499). Planetary boundary layer height retrieved from the Modern Era Retrospective-Analysis For Research And Applications (MERRA) product suggests typical PBL height of 1000-1200 m during the April-May peak biomass burning season. Cloud-Aerosol Lidar Orthogonal Polarisation (CALIOP) retrievals show the extent of smoke plume heights beyond the planetary boundary layer during the peak biomass burning month of April. However, comparison of fires in the Himalayan region with other regions and comparisons to aerosol index data from the Ozone Monitoring Instrument (OMI) suggest smoke plumes reaching less than 3 km. Our results on fires and smoke plume height relationships provide valuable information for addressing aerosol transport in the region.

  6. Mixed Layer Heights Derived from the NASA Langley Research Center Airborne High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Scarino, Amy J.; Burton, Sharon P.; Ferrare, Rich A.; Hostetler, Chris A.; Hair, Johnathan W.; Obland, Michael D.; Rogers, Raymond R.; Cook, Anthony L.; Harper, David B.; Fast, Jerome; Dasilva, Arlindo; Benedetti, Angela

    2012-01-01

    The NASA airborne High Spectral Resolution Lidar (HSRL) has been deployed on board the NASA Langley Research Center's B200 aircraft to several locations in North America from 2006 to 2012 to aid in characterizing aerosol properties for over fourteen field missions. Measurements of aerosol extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) during 349 science flights, many in coordination with other participating research aircraft, satellites, and ground sites, constitute a diverse data set for use in characterizing the spatial and temporal distribution of aerosols, as well as properties and variability of the Mixing Layer (ML) height. We describe the use of the HSRL data collected during these missions for computing ML heights and show how the HSRL data can be used to determine the fraction of aerosol optical thickness within and above the ML, which is important for air quality assessments. We describe the spatial and temporal variations in ML heights found in the diverse locations associated with these experiments. We also describe how the ML heights derived from HSRL have been used to help assess simulations of Planetary Boundary Layer (PBL) derived using various models, including the Weather Research and Forecasting Chemistry (WRF-Chem), NASA GEOS-5 model, and the ECMWF/MACC models.

  7. Comparison of Observed and Simulated Boundary Layer Height Estimates during Discover-Aq July 2011

    NASA Astrophysics Data System (ADS)

    Flynn, C.; Pickering, K. E.; Ferrare, R. A.; Scarino, A. J.; Delgado, R.; Martins, D. K.; Lenschow, D. H.; Loughner, C.; Thompson, A. M.

    2013-12-01

    The first deployment of the NASA Earth Venture -1 DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) project was conducted during July 2011 in the Baltimore-Washington region. The P-3B aircraft provided in situ vertical profiles of meteorological quantities, trace gases, and aerosols over six Maryland Department of the Environment (MDE) air quality monitoring sites over fourteen flight days. The UC-12 aircraft provided continuous remote sensing observations of aerosols over its flight track with the High Spectral Resolution Lidar (HSRL). Additionally, several MDE sites were equipped with the ground-based Micro-Pulse Lidar (MPL) instrument, also providing continuous, remotely sensed aerosol observations, and two sites launched ozonesondes during the campaign. A major goal of DISCOVER-AQ is to understand the processes linking trace gas column abundances to surface concentrations, including vertical mixing in the planetary boundary layer (PBL). In support of this goal, estimates of the PBL height output by the WRF/CMAQ model system (ACM2 PBL scheme and Pleim-Xiu surface layer scheme) were compared to observational estimates of PBL height during the July 2011 deployment. WRF/CMAQ typically demonstrated a high bias in PBL height relative to the meteorological PBL height estimates (those based on the potential temperature profile measured by the P-3B or ozonesondes), while the model demonstrated a low bias relative to PBL height estimates based on the aerosol backscatter profile (HSRL and MPL data). Additionally, the model tended to overpredict the PBL height on days when the PBL was well mixed, and underpredicted when the PBL was poorly mixed. Preliminary results from an intercomparison of the WRF model run with six different PBL schemes (ACM2, YSU, MYJ, MYNN, QNSE, and BouLac schemes) will also be presented.

  8. [Multi-wavelength spectral aerosol scale height in inshore in contrast with that in inland].

    PubMed

    Han, Yong; Rao, Rui-Zhong; Wang, Ying-Jian

    2009-01-01

    In the present paper, based on the exponential attenuation of atmospheric aerosol concentration with height, so using continuous spectrum sun-photometer, forward scatter visibility sensor and hygrothermograph, the authors measured the atmosphere column optical characteristic and plane spectral extinction coefficient on earth on the base of two experiments at some edge of ocean at the same time, respectively, set up the calculative method of multi-wavelength spectral aerosol scale height. Firstly, the authors obtained atmospheric horizontal extinction coefficient with forward scattering visibility sensor, which subtracted molecular extinction coefficient, and could get aerosol extinction coefficient near ground; Then, selecting sea salt model, using OPAC software, the authors also could calculate the aerosol extinction coefficient under different humidity (0%, 50%, 70%, 80%, 90%, 95%, 98% and 99%) and different wavelength (400, 450, 500, 550, 600, 650, 700 and 750 nm), the aerosol extinction coefficient was detected by visibility sensor, using interpolation method, respectively; Finally, using the data of atmospheric columniation optical thickness detected by continuous spectral sun-photometer and subtracted molecular optical thickness corresponding wavelengths were accounted out by Modtran 4. 0. The authors obtained the characteristic of spectral aerosol scale height of visible light (wavelength is 400, 440, 532, 550 and 690 nm): with wavelength increments, and spectral aerosol scale height was found to decline neither in inland nor in inshore in China; Spectral aerosol scale height in winter is higher than in summer in southeast inshore; but spectral aerosol scale height in winter is smaller in summer than in inland. PMID:19385200

  9. Outer layer effects in wind-farm boundary layers: Coriolis forces and boundary layer height

    NASA Astrophysics Data System (ADS)

    Allaerts, Dries; Meyers, Johan

    2015-11-01

    In LES studies of wind-farm boundary layers, scale separation between the inner and outer region of the atmospheric boundary layer (ABL) is frequently assumed, i.e., wind turbines are presumed to fall within the inner layer and are not affected by outer layer effects. However, modern wind turbine and wind farm design tends towards larger rotor diameters and farm sizes, which means that outer layer effects will become more important. In a prior study, it was already shown for fully-developed wind farms that the ABL height influences the power performance. In this study, we use the in-house LES code SP-Wind to investigate the importance of outer layer effects on wind-farm boundary layers. In a suite of LES cases, the ABL height is varied by imposing a capping inversion with varying inversion strengths. Results indicate the growth of an internal boundary layer (IBL), which is limited in cases with low inversion layers. We further find that flow deceleration combined with Coriolis effects causes a change in wind direction throughout the farm. This effect increases with decreasing boundary layer height, and can result in considerable turbine wake deflection near the end of the farm. The authors are supported by the ERC (ActiveWindFarms, grant no: 306471). Computations were performed on VSC infrastructiure (Flemish Supercomputer Center), funded by the Hercules Foundation and the Flemish Government-department EWI.

  10. Nomogram for the Height of the Daytime Mixed Layer

    NASA Astrophysics Data System (ADS)

    Nyrén, Kenneth; Gryning, Sven-Erik

    A method to construct a nomogram of the daytime mixed-layer-height evolution is presented. The nomogram will be specific for a given location and land surface type and is intended to be an easy tool to achieve a general understanding of mixed-layer behaviour. Also it is a pedagogical graphical one-pager that displays the bulk of data that controls the evolution of the mixed layer. Nomograms from northern, central and southern Europe are presented and discussed. Comparison with data from two sites shows good agreement although the nomograms overestimated the mixing height when it was low.

  11. Behaviour of Atmospheric Boundary Layer Height at Dome C, Antarctica

    NASA Astrophysics Data System (ADS)

    Pietroni, I.; Argentini, S.

    2009-09-01

    The Antarctic Atmospheric Boundary Layer presents characteristics which are substantially different from the mid-latitudes ABLs. On the Antarctic plateau two different extreme situations are observed. During the summer a mixing height develops during the warmer hours of the day although the sensible heat flux is reduced compared to that at mid-latitudes. During the winter a long lived stable boundary layer is continuously present, the residual layer is never observed, consequently the inversion layer is connected at the free atmosphere. To understand the stable ABL process the STABLEDC (Study of the STAble Boundary Layer Environmental at Dome C) experimental field was held at Concordia, the French Italian plateau station at Dome C, during 2005. In the same period the RMO (Routine Measurements Observations) started. The data included turbulence data at the surface, temperature profiles by a microwave profiler (MTP-5P), a mini-sodar and radio-soundings. In this work we will show the results of a comparison of the ABL height at Concordia (3233 m a.s.l) during the summer and the winter using direct measurements and parameterization. The winter ABL height was estimated directly using experimental data (radio-soundings and radiometer temperature and wind velocity profiles) and different methods proposed in literature. The stable ABL height was also estimated using the formulation proposed by Zilitinkevich et al. (2007) for the long-lived stable boundary layer. The correlation of ABL height with the temperature and wind speed is also shown. The summer mixing height was instead estimated by mini-sodar data and compared with the height given by the model suggested by Batchvarova and Gryning (1991) which use as input the turbulence data.

  12. Aerosol buffering of marine boundary layer cloudiness

    NASA Astrophysics Data System (ADS)

    Kazil, J.; Feingold, G.; Wang, H.

    2010-12-01

    The role of aerosol particles in maintaining a cloudy boundary layer in the remote marine environment is explored. It has previously been shown that precipitation can result in the transition from a closed- to open-cellular state but that the boundary layer cannot maintain this open-cell state without a resupply of particles. Potential sources include wind-driven production of sea salt particles from the ocean, nucleation from the gas phase, and entrainment from the free troposphere. Here we investigate with model simulations how the interplay of cloud properties, aerosol production, and boundary layer dynamics results in aerosol sources acting as a buffer against processes that destabilize cloudiness and the dynamic state of the marine boundary layer. For example, at nighttime, cloud liquid water increases in the absence of solar heating, resulting in increased precipitation, stronger cloud top cooling, accelerated boundary layer turbulence, and faster surface wind speeds. Faster surface wind speeds drive an enhanced flux of sea salt aerosol, at a time when aerosol particles are scavenged more readily by enhanced precipitation. In contrast, absorption of solar radiation during daytime reduces cloud water, decelerates boundary layer turbulence, reduces surface wind speeds, and therefore slows surface emissions. This is compensated by nucleation of small aerosol particles from the gas phase in response to the nigh complete removal of cloud condensation nuclei in precipitating open cell walls. These newly formed particles need to grow to larger sizes before they can serve as cloud condensation nuclei (CCN), but will likely contribute to the CCN population during the nighttime and, together with ocean emissions, buffer the system against precipitation removal.

  13. Characterization of the planetary boundary layer height and structure by Raman lidar: comparison of different approaches

    NASA Astrophysics Data System (ADS)

    Summa, D.; Di Girolamo, P.; Stelitano, D.; Cacciani, M.

    2013-06-01

    The Planetary Boundary Layer (PBL) includes the portion of the atmosphere which is directly influenced by the presence of the Earth's surface. Aerosol particles trapped within the PBL can be used as tracers to study the boundary-layer vertical structure and time variability. As a result of this, elastic backscatter signals collected by lidar systems can be used to determine the height and the internal structure of the PBL. The present analysis considers three different methods to estimate the PBL height. A first method is based on the determination of the first order derivative of the logarithm of the range-corrected elastic lidar signals. Estimates of the PBL height for specific case studies obtained from this approach are compared with simultaneous estimates from the potential temperature profiles measured by radiosondes launched simultaneously to lidar operation. Additional estimates of the boundary layer height are based on the determination of the first order derivative of the range-corrected rotational Raman lidar signals. This latter approach results to be successfully applicable also in the afternoon-evening decaying phase of the PBL, when the effectiveness of the approach based on the elastic lidar signals may be compromised or altered by the presence of the residual layer. Results from these different approaches are compared and discussed in the paper, with a specific focus on selected case studies collected by the University of Basilicata Raman lidar system BASIL during the Convective and Orographically-induced Precipitation Study (COPS).

  14. Characterization of the planetary boundary layer height and structure by Raman lidar: comparison of different approaches

    NASA Astrophysics Data System (ADS)

    Summa, D.; Di Girolamo, P.; Stelitano, D.; Cacciani, M.

    2013-12-01

    The planetary boundary layer (PBL) includes the portion of the atmosphere which is directly influenced by the presence of the earth's surface. Aerosol particles trapped within the PBL can be used as tracers to study the boundary-layer vertical structure and time variability. As a result of this, elastic backscatter signals collected by lidar systems can be used to determine the height and the internal structure of the PBL. The present analysis considers three different methods to estimate the PBL height. The first method is based on the determination of the first-order derivative of the logarithm of the range-corrected elastic lidar signals. Estimates of the PBL height for specific case studies obtained through this approach are compared with simultaneous estimates from the potential temperature profiles measured by radiosondes launched simultaneously to lidar operation. Additional estimates of the boundary layer height are based on the determination of the first-order derivative of the range-corrected rotational Raman lidar signals. This latter approach results to be successfully applicable also in the afternoon-evening decaying phase of the PBL, when the effectiveness of the approach based on the elastic lidar signals may be compromised or altered by the presence of the residual layer. Results from these different approaches are compared and discussed in the paper, with a specific focus on selected case studies collected by the University of Basilicata Raman lidar system BASIL during the Convective and Orographically-induced Precipitation Study (COPS).

  15. A new automatic Planetary Boundary Layers height detection and diurnal evolution with compact EZ Lidar

    NASA Astrophysics Data System (ADS)

    Loaec, S.; Boquet, M.,; Sauvage, L.; Lolli, S.; Rouget, V.

    2009-04-01

    Bigger strongly urbanized cities in the world are often exposed to atmospheric pollution events. To understand the chemical and physical processes that are taking place in these areas it is necessary to describe correctly the Planetary Boundary Layer (PBL) dynamics and the PBL height evolution. For these proposals, a compact and rugged eye safe UV Lidar, the EZLIDAR™, was developed together by CEA/LMD and LEOSPHERE (France) to study and investigate structural and optical properties of clouds and aerosols and PBL time evolution. EZLIDAR™ has been validated by different remote and in-situ instruments as MPL Type-4 Lidar manufactured by NASA at ARM/SGP site or the LNA (Lidar Nuage Aerosol) at the Laboratoire de Metereologie Dynamique LMD (France) and during several intercomparison campaigns. EZLIDAR™ algorithm retrieves automatically the PBL height in real-time. The method is based on the detection of the slope of the signal linked to a sharp change in concentration of the aerosols. Once detected, the different layers are filtered on a 15mn sample and classified between nocturnal, convective or residual layer, depending on the time and date. This method has been validated against those retrieved by the algorithm STRAT from data acquired at IPSL, France, showing 95% of correlation. In this paper are presented the results of the intercomparison campaign that took place in Orleans, France in the framework of ICOS (Integrated Carbon Observation System) project, where the EZ Lidar™ worked under all weather conditions, clear sky, fog, low clouds, during the whole month of October 2008. Moreover, thanks to its 3D scanning capability, the EZLIDAR was able to provide the variability of the PBL height around the site, enabling the scientists to estimate the flux intensities that play a key role in the radiative transfer budget and in the atmospheric pollutants dispersion.

  16. An automatic Planetary Boundary Layer height retrieval method with compact EZ backscattering Lidar

    NASA Astrophysics Data System (ADS)

    Loaec, S.; Sauvage, L.; Boquet, M.; Lolli, S.; Rouget, V.

    2009-09-01

    Bigger strongly urbanized cities in the world are often exposed to atmospheric pollution events. To understand the chemical and physical processes that are taking place in these areas it is necessary to describe correctly the Planetary Boundary Layer (PBL) dynamics and the PBL height evolution. For these proposals, a compact and rugged eye safe UV Lidar, the EZLIDAR™, was developed together by CEA/LMD and LEOSPHERE (France) to study and investigate structural and optical properties of clouds and aerosols and PBL time evolution. EZLIDAR™ has been validated by different remote and in-situ instruments as MPL Type-4 Lidar manufactured by NASA at ARM/SGP site or the LNA (Lidar Nuage Aerosol) at the Laboratoire de Metereologie Dynamique LMD (France) and during several intercomparison campaigns. EZLIDAR™ algorithm retrieves automatically the PBL height in real-time. The method is based on the detection of the slope of the signal linked to a sharp change in concentration of the aerosols. Once detected, the different layers are filtered on a 15mn sample and classified between nocturnal, convective or residual layer, depending on the time and date. This method has been validated against those retrieved by the algorithm STRAT from data acquired at IPSL, France, showing 95% of correlation. In this paper are presented the results of the intercomparison campaign that took place in Orleans, France and Mace Head, Ireland in the framework of ICOS (Integrated Carbon Observation System) project, where the EZ Lidar™ worked under all weather conditions, clear sky, fog, low clouds, during the whole month of October 2008. Moreover, thanks to its 3D scanning capability, the EZLIDAR was able to provide the variability of the PBL height around the site, enabling the scientists to estimate the flux intensities that play a key role in the radiative transfer budget and in the atmospheric pollutants dispersion.

  17. Atmospheric Boundary Layer Height Evolution with Lidar in Buenos Aires from 2008 to 2011

    NASA Astrophysics Data System (ADS)

    Pawelko, Ezequiel Eduardo; Salvador, Jacobo Omar; Ristori, Pablo Roberto; Pallotta, Juan Vicente; Otero, Lidia Ana; Quel, Eduardo Jaime

    2016-06-01

    The analysis of the atmospheric boundary layer top height evolution is obtained from 2008 to 2011 in Buenos Aires using the multiwavelength lidar located at CEILAP (CITEDEF-CONICET) (34°33' S; 58°30' W; 17 m asl). Algorithms recognition based on covariance wavelet transform are applied to obtain seasonal statistics. This method is being evaluated for use in the Lidar Network in Argentina and it is being deployed in Patagonia region currently. The technique operates in real time in both low and high aerosol loads and with almost no human supervision.

  18. Effects of explosively venting aerosol-sized particles through earth-containment systems on the cloud-stabilization height

    SciTech Connect

    Dyckes, G.W.

    1980-07-01

    A method of approximating the cloud stabilization height for aerosol-sized particles vented explosively through earth containment systems is presented. The calculated values for stabilization heights are in fair agreement with those obtained experimentally.

  19. Are Satellite-Retrieved Correlations Between Cloud-Top-Height and Aerosol Optical Depth Evidence of Aerosol Invigoration of Convection?

    NASA Astrophysics Data System (ADS)

    Stier, P.; Gryspeerdt, E.; Grandey, B. S.; Wagner, T. M.; Kipling, Z.

    2013-12-01

    A robust negative correlation between cloud top pressure (CTP) and aerosol optical depth (AOD) has been documented in a number of studies and triggered hypotheses on aerosol invigoration of convective clouds. However, correlation based analysis is limited in its explanatory power as it does not directly establish physical causality between the correlated properties which may be cross-correlated with other meteorological factors. In this study we combine the global aerosol-climate model ECHAM-HAM with mechanistic coupling of the aerosol microphysics (HAM) to the two-moment cloud microphysics in the Convective Cloud Field Model (CCFM) and satellite data from SEVIRI, MODIS, ISCCP, CALIOP and CloudSat. CCFM explicitly simulates a spectrum of convective cloud top heights within each grid box, providing enhanced realism over traditional mass flux schemes. Consistency is established through sampling of the models at satellite overpass times and the use of ISCCP and COSP satellite simulators in the model. We employ this setup to investigate the contributions of aerosol-cloud interactions and meteorological cross-correlations to AOD--CTP correlations. Our analysis shows that a significant fraction of the observed AOD-CTP relationship is driven by the meteorological link between CTP and cloud fraction (CF), which itself is strongly linked to AOD via the humidification of aerosol in humid (hence preferentially cloudy) environments. Our results shed light on this controversial issue with potentially significant climate implications and emphasise the difficulty to constrain for meteorological variability in observational studies of aerosol-cloud interactions.

  20. Composition and physical properties of the Asian Tropopause Aerosol Layer and the North American Tropospheric Aerosol Layer

    PubMed Central

    Yu, Pengfei; Toon, Owen B; Neely, Ryan R; Martinsson, Bengt G; Brenninkmeijer, Carl A M

    2015-01-01

    Recent studies revealed layers of enhanced aerosol scattering in the upper troposphere and lower stratosphere over Asia (Asian Tropopause Aerosol Layer (ATAL)) and North America (North American Tropospheric Aerosol Layer (NATAL)). We use a sectional aerosol model (Community Aerosol and Radiation Model for Atmospheres (CARMA)) coupled with the Community Earth System Model version 1 (CESM1) to explore the composition and optical properties of these aerosol layers. The observed aerosol extinction enhancement is reproduced by CESM1/CARMA. Both model and observations indicate a strong gradient of the sulfur-to-carbon ratio from Europe to the Asia on constant pressure surfaces. We found that the ATAL is mostly composed of sulfates, surface-emitted organics, and secondary organics; the NATAL is mostly composed of sulfates and secondary organics. The model also suggests that emission increases in Asia between 2000 and 2010 led to an increase of aerosol optical depth of the ATAL by 0.002 on average which is consistent with observations. Key Points The Asian Tropopause Aerosol Layer is composed of sulfate, primary organics, and secondary organics The North American Tropospheric Aerosol Layer is mostly composed of sulfate and secondary organics Aerosol Optical Depth of Asian Tropopause Aerosol Layer increases by 0.002 from 2000 to 2010 PMID:26709320

  1. Methods for determining the height of the atmospheric boundary layer

    SciTech Connect

    Sugiyama, Gayle; Nasstrom, John S.

    1999-02-01

    The Atmospheric Release Advisory Capability (ARAC) is an operational emergency response program which provides real-time dose assessments of airborne pollutant releases. This report reviews methodologies for determining the height of the atmospheric boundary layer (ABL), which were investigated for use in the next generation of ARAC diagnostic and dispersion models. The ABL height, hABL, is an essential parameter in atmospheric dispersion modeling, controlling the extent of the vertical mixing of pollutants near the surface. Although eventually instrumentation (radiosonde, lidar, sodar, etc.) may provide accurate means for determining hABL, at present the availability of such data is too limited to provide a general capability for ARAC. The current operational ARAC diagnostic models use a fixed value of hABL for any given time. ARAC's new models support a horizontally-varying atmospheric boundary layer height, which is used to generate meteorological (mean wind, temperature, etc.) and turbulence fields. The purpose of the present work is to develop methods to derive the ABL height for all atmospheric stability regimes. One of our key requirements is to provide approaches which are applicable to routinely available data, which may be of limited temporal and spatial resolution. The final objective is to generate a consistent set of meteorological and turbulence or eddy diffusivity fields to drive the new ARAC dispersion model. A number of alternative definitions of the atmospheric boundary layer exist, leading to different approaches to deriving hABL. The definitions are based on either the turbulence characteristics of the atmosphere or the vertical structure of one or more meteorological variables. Most diagnostic analyses determine hABL from profiles of temperature or occasionally wind. A class of methods of considerable current interest are based on Richardson number criteria. Prognostic methods calculate the

  2. Pulse height response of an optical particle counter to monodisperse aerosols

    NASA Technical Reports Server (NTRS)

    Wilmoth, R. G.; Grice, S. S.; Cuda, V.

    1976-01-01

    The pulse height response of a right angle scattering optical particle counter has been investigated using monodisperse aerosols of polystyrene latex spheres, di-octyl phthalate and methylene blue. The results confirm previous measurements for the variation of mean pulse height as a function of particle diameter and show good agreement with the relative response predicted by Mie scattering theory. Measured cumulative pulse height distributions were found to fit reasonably well to a log normal distribution with a minimum geometric standard deviation of about 1.4 for particle diameters greater than about 2 micrometers. The geometric standard deviation was found to increase significantly with decreasing particle diameter.

  3. Atmospheric Aerosol and Thermal Structure in the Boundary Layer Over the Los Angeles Basin

    NASA Technical Reports Server (NTRS)

    Johnson, Warren B.

    1973-01-01

    A field study using a mobile lidar was recently conducted in the L. A. Basin, California, to (1) examine the relationship between the vertical aerosol and the thermal structure, and (2) map the vertical aerosol structure in the atmospheric boundary layer over the basin. These data are needed for use in the development of a mixing-depth submodel required for photochemical air Quality simulation models. Toward these ends, a series of lidar aerosol measurements in conjunction with balloon and aircraft temperature soundings were taken at a site in El Monte, and in a mobile mode along a 90-mile freeway loop between El Monte, Santa Monica, and Long Beach. The lidar data are presented in the form of time-height and distance-height cross sections. The results indicate that, although aerosol concentrations are frequently present above the base of the marine inversion, these are generally in stratified layers in contrast to the more uniform nature of the lower convective layer, permitting the mixing depth to be distinguished on this basis. The lidar-derived mixing depths are well correlated (within 100 m) with daytime temperature inversions. Other significant features shown by the lidar data include large Basin-wide mixing-depth variations, waves with amplitudes of 200-300 m and wavelengths of 1000-1500 m on the lower aerosol layer, and apparent aerosol "chimneys" with overrunning in the vicinity of convergence zones.

  4. Aerosol - cloud - water vapor relations for cloud systems of different heights

    NASA Astrophysics Data System (ADS)

    Stathopoulos, Stavros; Kourtidis, Konstantinos; Georgoulias, Aristeidis

    2016-04-01

    Here we examine the annual and seasonal aerosol - cloud relations over three major urban clusters of China, for different cloud heights and atmospheric water vapor amounts, using a decade of Aerosol Optical Depth at 550nm (AOD), Cloud Cover (CC), Cloud Optical Depth (COD), Water Vapor (WV) and Cloud Top Pressure (CTP) data from the MODIS instrument. Over all regions (spanning from temperate to tropical monsoon climates) and for all seasons, CC is found to increase with AOD, WV and cloud height. Aerosols, at low WV environments and under constant cloud height, have less impact on CC than at high WV environments. In addition, AOD has a varying influence on COD depending on CTP. Finally, COD is found to increase with height for low and middle height clouds, and with increasing AOD, especially at low AOD, the latter being in line with the expected first indirect effect. This research has been financed under the FP7 Programme MarcoPolo (Grand Number 606953, Theme SPA.2013.3.2-01).

  5. Planetary Boundary Layer and aerosol interactions over the Indian sub-continent

    NASA Astrophysics Data System (ADS)

    Patil, M. N.; Patil, S. D.; Waghmare, R. T.; Dharmaraj, T.

    2014-05-01

    Aerosols, both natural as well as anthropogenic, affect the radiative forcing of Earth's climate and reduce surface albedo. The Planetary Boundary Layer (PBL) height, which depends upon surface heat budget, is analyzed considering the increase in green house gases (GHGs) from pre-industrial to post-industrial era. The PBL climatology shows deeper PBL during pre-monsoon and summer monsoon seasons as compared to post-monsoon and winter. The PBL height has decreased in post-industrial decade compared to pre-industrial decade. The PBL height reduction is due to increasing aerosol and GHGs' concentrations in the recent decades, which causes surface warming and upper tropospheric cooling. Similarly, due to higher loading of the volcanic aerosol injected from the low latitude eruptions, the atmospheric circulation has been affected.

  6. Influences on the Height of the Stable Boundary Layer as seen in LES

    SciTech Connect

    Kosovic, B; Lundquist, J

    2004-06-15

    Climate models, numerical weather prediction (NWP) models, and atmospheric dispersion models often rely on parameterizations of planetary boundary layer height. In the case of a stable boundary layer, errors in boundary layer height estimation can result in gross errors in boundary-layer evolution and in prediction of turbulent mixing within the boundary layer.

  7. Observations of the atmospheric boundary layer height under marine upstream flow conditions at a coastal site

    NASA Astrophysics Data System (ADS)

    PeñA, A.; Gryning, S.-E.; Hahmann, A. N.

    2013-02-01

    AbstractWe investigate several lidar-type instruments and methodologies for boundary <span class="hlt">layer</span> <span class="hlt">height</span> (BLH) estimation during 2 days at a coastal site for winds that experience marine upstream flow conditions. Wavelet and profile fitting procedures on the <span class="hlt">aerosol</span> backscatter signals from a ceilometer and an <span class="hlt">aerosol</span> lidar reveal similar BLHs, but their agreement depends on the presence of clouds and the instrument signal, among others. BLHs derived by a threshold on the carrier-to-noise profiles of a wind lidar agree well with those derived by using a threshold on the backscatter profile of the ceilometer and are used as reference for a 10 day BLH intercomparison. Furthermore, the BLHs from the <span class="hlt">aerosol</span> analysis are comparable to those derived from wind speed and direction profiles from combined mast/wind lidar measurements. The BLH derived from simulations performed with the Weather Research and Forecasting (WRF) model shows similar behavior compared to the lidar observations. The seasonal diurnal variation of the BLH for 2010, derived from the wind lidar and ceilometer thresholds, shows similar BLHs but generally higher values compared to that from WRF. No clear BLH diurnal variation is observed neither from the observations nor from the WRF model outputs, except in summer for the latter. Both observations and WRF model simulations reveal higher BLHs during autumn compared to spring time. These BLHs are used to evaluate the intra-annual variation and show high peaks in September, November, and February.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AMT.....7.1701W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AMT.....7.1701W"><span id="translatedtitle">Estimation of atmospheric mixing <span class="hlt">layer</span> <span class="hlt">height</span> from radiosonde data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, X. Y.; Wang, K. C.</p> <p>2014-06-01</p> <p>Mixing <span class="hlt">layer</span> <span class="hlt">height</span> (h) is an important parameter for understanding the transport process in the troposphere, air pollution, weather and climate change. Many methods have been proposed to determine h by identifying the turning point of the radiosonde profile. However, substantial differences have been observed in the existing methods (e.g. the potential temperature (θ), relative humidity (RH), specific humidity (q) and atmospheric refractivity (N) methods). These differences are associated with the inconsistency of the temperature and humidity profiles in a boundary <span class="hlt">layer</span> that is not well mixed, the changing measurability of the specific humidity and refractivity with <span class="hlt">height</span>, the measurement error of humidity instruments within clouds, and the general existence of clouds. This study proposes a method to integrate the information of temperature, humidity and cloud to generate a consistent estimate of h. We apply this method to high vertical resolution (~ 30 m) radiosonde data that were collected at 79 stations over North America during the period from 1998 to 2008. The data are obtained from the Stratospheric Processes and their Role in Climate Data Center (SPARC). The results show good agreement with those from N method as the information of temperature and humidity contained in N; however, cloud effects that are included in our method increased the reliability of our estimated h. From 1988 to 2008, the climatological h over North America was 1675 ± 303 m with a strong east-west gradient: higher values (generally greater than 1800 m) occurred over the Midwest US, and lower values (usually less than 1400 m) occurred over Alaska and the US West Coast.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AMTD....7.1247W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AMTD....7.1247W"><span id="translatedtitle">Estimation of atmospheric mixing <span class="hlt">layer</span> <span class="hlt">height</span> from radiosonde data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, X. Y.; Wang, K. C.</p> <p>2014-02-01</p> <p>Mixing <span class="hlt">layer</span> <span class="hlt">height</span> (h) is an important parameter for understanding the transport process in the troposphere, air pollution, weather and climate change. Many methods have been proposed to determine h by identifying the turning point of the radiosonde profile. However, substantial differences have been observed in the existing methods (e.g., the potential temperature (θ), relative humidity (RH), specific humidity (q) and atmospheric refractivity (N) methods). These differences are associated with the inconsistency of the temperature and humidity profiles in a boundary <span class="hlt">layer</span> that is not well mixed, the changing measurability of the specific humidity and refractivity with <span class="hlt">height</span>, the measurement error of humidity instruments within clouds, and the general existence of clouds. This study proposes a method to integrate the information of temperature, humidity and cloud to generate a consistent estimate of h. We apply this method to high vertical resolution (~ 30 m) radiosonde data that were collected at 79 stations over North America during the period from 1998 to 2008; the data are obtained from the Stratospheric Processes and their Role in Climate Data Center (SPARC). The results show good agreement with those from N method as the information of temperature and humidity contained in N; however cloud effects that are included in our method increased the reliability of h. Furthermore, our results agree well with the independent h that was determined from lidar observations. From 1988 to 2008, the climatological h over North America was 1675± 303 m with a strong east-west gradient: higher values (generally greater than 1800 m) occurred over the Midwest US, and lower values (usually less than 1400 m) occurred over Alaska and the US west coast.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713873U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713873U"><span id="translatedtitle">Dust <span class="hlt">layer</span> profiling using an <span class="hlt">aerosol</span> dropsonde</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ulanowski, Zbigniew; Kaye, Paul Henry; Hirst, Edwin; Wieser, Andreas; Stanley, Warren</p> <p>2015-04-01</p> <p>Routine meteorological data is obtained in the atmosphere using disposable radiosondes, giving temperature, pressure, humidity and wind speed. Additional measurements are obtained from dropsondes, released from research aircraft. However, a crucial property not yet measured is the size and concentration of atmospheric particulates, including dust. Instead, indirect measurements are employed, relying on remote sensing, to meet the demands from areas such as climate research, air quality monitoring, civil emergencies etc. In addition, research aircraft can be used in situ, but airborne measurements are expensive, and aircraft use is restricted to near-horizontal profiling, which can be a limitation, as phenomena such as long-range transport depend on the vertical distribution of <span class="hlt">aerosol</span>. The Centre for Atmospheric and Instrumentation Research at University of Hertfordshire develops light-scattering instruments for the characterization of <span class="hlt">aerosols</span> and cloud particles. Recently a range of low-cost, miniature particle counters has been created, intended for use with systems such as disposable balloon-borne radiosondes, dropsondes, or in dense ground-based sensor networks. Versions for different particle size ranges exist. They have been used for vertical profiling of <span class="hlt">aerosols</span> such as mineral dust or volcanic ash. A disadvantage of optical particle counters that sample through a narrow inlet is that they can become blocked, which can happen in cloud, for example. Hence, a different counter version has been developed, which can have open-path geometry, as the sensing zone is defined optically rather than being delimited by the flow system. This counter has been used for ground based air-quality monitoring around Heathrow airport. The counter has also been adapted for use with radiosondes or dropsondes. The dropsonde version has been successfully tested by launching it from research aircraft together with the so-called KITsonde, developed at the Karlsruhe Institute of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1818254W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1818254W"><span id="translatedtitle">Radiative effects of tropospheric <span class="hlt">aerosols</span> on the evolution of the atmospheric boundary <span class="hlt">layer</span> and its feedback on the haze formation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wei, Chao; Su, Hang; Cheng, Yafang</p> <p>2016-04-01</p> <p>Planetary boundary <span class="hlt">layer</span> (PBL) plays a key role in air pollution dispersion and influences day-to-day air quality. Some studies suggest that high <span class="hlt">aerosol</span> loadings during severe haze events may modify PBL dynamics by radiative effects and hence enhance the development of haze. This study mainly investigates the radiative effects of tropospheric <span class="hlt">aerosols</span> on the evolution of the atmospheric boundary <span class="hlt">layer</span> by conducting simulations with Weather Research and Forecasting single-column model (WRF-SCM). We find that high <span class="hlt">aerosol</span> loading in PBL depressed boundary <span class="hlt">layer</span> <span class="hlt">height</span> (PBLH). But the magnitude of the changes of PBLH after adding <span class="hlt">aerosol</span> loadings in our simulations are small and can't explain extreme high <span class="hlt">aerosol</span> concentrations observed. We also investigate the impacts of the initial temperature and moisture profiles on the evolution of PBL. Our studies show that the impact of the vertical profile of moisture is comparable with <span class="hlt">aerosol</span> effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/15009901','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/15009901"><span id="translatedtitle">A Comparison of <span class="hlt">Aerosol-Layer</span> and Convective Boundary-<span class="hlt">Layer</span> Structure over a Mountain Range during STAAARTE '97</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>De Wekker, Stephan; Steyn, D. G.; Nyeki, Stephan</p> <p>2004-11-01</p> <p>The temporal evolution and spatial structure of the <span class="hlt">aerosol</span> <span class="hlt">layer</span> (AL) <span class="hlt">height</span> as observed with an airborne downlooking lidar over the Swiss Alps was investigated with a three dimensional mesoscale numerical model and a particle dispersion model. Convective boundary <span class="hlt">layer</span> (CBL) <span class="hlt">heights</span> were derived from the mesoscale model output, and the behavior of surface-released particles was investigated with the particle dispersion model. While a previous investigation, using data from the same field study, equated the observed AL <span class="hlt">height</span> with the CBL <span class="hlt">height</span>, the results of the current investigation indicate that there is a considerable difference between AL and CBL <span class="hlt">heights</span> caused by mixing and transport processes between the CBL and the free atmosphere. CBL <span class="hlt">heights</span> show a more terrain-following behavior and are lower than AL <span class="hlt">heights</span>. We argue that processes causing the difference between AL and CBL <span class="hlt">heights</span> are common over mountainous terrain and that the AL <span class="hlt">height</span> is a length scale that needs t o be considered in air pollution studies in mountainous terrain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910016141','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910016141"><span id="translatedtitle">Tropospheric ozone and <span class="hlt">aerosols</span> measured by airborne lidar during the 1988 Arctic boundary <span class="hlt">layer</span> experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.</p> <p>1991-01-01</p> <p>Ozone (O3) and <span class="hlt">aerosol</span> distributions were measured from an aircraft using a differential absorption lidar (DIAL) system as part of the 1988 NASA Global Tropospheric Experiment - Arctic Boundary <span class="hlt">Layer</span> Experiment (ABLE-3A) to study the sources and sinks of gases and <span class="hlt">aerosols</span> over the tundra regions of Alaska during the summer. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low <span class="hlt">aerosol</span> scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere. Several cases of continental polar air masses were examined during the experiment. The <span class="hlt">aerosol</span> scattering associated with these air masses was very low, and the atmospheric distribution of <span class="hlt">aerosols</span> was quite homogeneous for those air masses that had been transported over the ice for greater than or = 3 days. The transition in O3 and <span class="hlt">aerosol</span> distributions from tundra to marine conditions was examined several times. The <span class="hlt">aerosol</span> data clearly show an abrupt change in <span class="hlt">aerosol</span> scattering properties within the mixed <span class="hlt">layer</span> from lower values over the tundra to generally higher values over the water. The distinct differences in the <span class="hlt">heights</span> of the mixed <span class="hlt">layers</span> in the two regions was also readily apparent. Several cases of enhanced O3 were observed during ABLE-3 in conjunction with enhanced <span class="hlt">aerosol</span> scattering in <span class="hlt">layers</span> in the free atmosphere. Examples are presented of the large scale variations of O3 and <span class="hlt">aerosols</span> observed with the airborne lidar system from near the surface to above the tropopause over the Arctic during ABLE-3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010872','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010872"><span id="translatedtitle">Stereoscopic <span class="hlt">Height</span> and Wind Retrievals for <span class="hlt">Aerosol</span> Plumes with the MISR INteractive eXplorer (MINX)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nelson, D.L.; Garay, M.J.; Kahn, Ralph A.; Dunst, Ben A.</p> <p>2013-01-01</p> <p>The Multi-angle Imaging SpectroRadiometer (MISR) instrument aboard the Terra satellite acquires imagery at 275-m resolution at nine angles ranging from 0deg (nadir) to 70deg off-nadir. This multi-angle capability facilitates the stereoscopic retrieval of <span class="hlt">heights</span> and motion vectors for clouds and <span class="hlt">aerosol</span> plumes. MISR's operational stereo product uses this capability to retrieve cloud <span class="hlt">heights</span> and winds for every satellite orbit, yielding global coverage every nine days. The MISR INteractive eXplorer (MINX) visualization and analysis tool complements the operational stereo product by providing users the ability to retrieve <span class="hlt">heights</span> and winds locally for detailed studies of smoke, dust and volcanic ash plumes, as well as clouds, at higher spatial resolution and with greater precision than is possible with the operational product or with other space-based, passive, remote sensing instruments. This ability to investigate plume geometry and dynamics is becoming increasingly important as climate and air quality studies require greater knowledge about the injection of <span class="hlt">aerosols</span> and the location of clouds within the atmosphere. MINX incorporates features that allow users to customize their stereo retrievals for optimum results under varying <span class="hlt">aerosol</span> and underlying surface conditions. This paper discusses the stereo retrieval algorithms and retrieval options in MINX, and provides appropriate examples to explain how the program can be used to achieve the best results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.A41D0089K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.A41D0089K&link_type=ABSTRACT"><span id="translatedtitle">Dependence of the drizzle growth process on the cloud top <span class="hlt">height</span> and its relevance to the <span class="hlt">aerosol</span> vertical profile</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kawamoto, K.; Suzuki, K.</p> <p>2013-12-01</p> <p>Transitional processes among cloud droplets, drizzle and raindrops are still uncertain and more efforts are required for the better understanding. In this situation, difference in the drizzle growth process was examined according to the cloud top <span class="hlt">height</span> using the CloudSat and MODIS synergetic datasets. From the CloudSat products such as 2B-GEOPROF, 2B-TAU, ECMWF-AUX, only one-<span class="hlt">layered</span> water clouds whose top temperatures were warmer than 273K were extracted over China (a circular area having a diameter of 1800km of the center at 35°N and 120°E) and over ocean (a circular area having a diameter of 1500km of the center at 35°N and 150°E). Then a threshold of 3km of the cloud top <span class="hlt">height</span> was adopted to divide the extracted clouds into upper and lower cases. First, the probability distribution functions (PDF) of the cloud droplet number density (Nc) and the effective particle radius (Re) were calculated for these four cases (land/ocean/upper/lower). Nc was obtained assuming the adiabatic liquid water content from MODIS-derived cloud optical depth and Re. Oceanic clouds had fewer Nc than land clouds, and almost the same for upper and lower cases. Land clouds had more Nc for the lower case than for the higher case. On the other hand, oceanic clouds had larger Re than land clouds, and almost the same for upper and lower cases. Land clouds had smaller Re for the lower case than for the higher case. These results quite agreed with our existing knowledge on the vertical profile of the <span class="hlt">aerosol</span> number concentration over ocean (pristine) and land (polluted). Although the number of <span class="hlt">aerosol</span> particles is fewer and almost the same regardless of the <span class="hlt">height</span> over the ocean, it is more near the surface and it rapidly decreases according to the <span class="hlt">height</span> over the land. Next, examining PDF of the radar reflectivity (Ze), we found that although PDFs of Ze were almost the same for oceanic clouds regardless of the cloud top <span class="hlt">height</span>, PDF of land lower clouds were less frequent at around from</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A24B..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A24B..08S"><span id="translatedtitle">Radiative Impacts of Elevated <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> from Different Origins</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sauer, D. N.; Weinzierl, B.; Gasteiger, J.; Heimerl, K.</p> <p>2014-12-01</p> <p><span class="hlt">Aerosol</span> particles are omnipresent in the Earth's atmosphere and have important impacts on weather and climate by their effects on the atmospheric radiative balance. With the advent of more and more sophisticated representations of atmospheric processes in earth system models, the lack of reliable input data on <span class="hlt">aerosols</span> leads to significant uncertainties in the prediction of future climate scenarios. In recent years large discrepancies in radiative forcing estimates from <span class="hlt">aerosol</span> <span class="hlt">layers</span> in modeling studies have been revealed emphasizing the need for detailed and systematic observations of <span class="hlt">aerosols</span>. Airborne in-situ measurements represent an important pillar for validating both model results and retrievals of <span class="hlt">aerosol</span> distributions and properties from remote sensing methods on global scales. However, detailed observations are challenging and therefore are subject to substantial uncertainties themselves. Here we use data from airborne in-situ measurements of elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> from various field experiments in different regions of the world. The data set includes Saharan mineral dust <span class="hlt">layers</span> over Africa, the Atlantic Ocean and the Caribbean from the SALTRACE and the SAMUM campaigns as well as long-range transported biomass burning <span class="hlt">aerosol</span> <span class="hlt">layers</span> from wild fires in the Sahel region and North America measured over the tropical Atlantic Ocean, Europe and the Arctic detected during SAMUM2, CONCERT2011, DC3 and ACCESS 2012. We aim to characterize the effects of the measured <span class="hlt">aerosol</span> <span class="hlt">layers</span>, in particular with respect to ageing, mixing state and vertical structure, on the overall atmospheric radiation budget as well as local heating and cooling rates. We use radiative transfer simulations of short and long-wave radiation and <span class="hlt">aerosol</span> optical properties derived in a consistent way from the in-situ observations of microphysical properties using T-matrix calculations. The results of this characterization will help to improve the parameterization of the effects of elevated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860020281','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860020281"><span id="translatedtitle">Chemical analysis of <span class="hlt">aerosol</span> in the Venusian cloud <span class="hlt">layer</span> by reaction gas chromatography on board the Vega landers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gelman, B. G.; Drozdov, Y. V.; Melnikov, V. V.; Rotin, V. A.; Khokhlov, V. N.; Bondarev, V. B.; Dolnikov, G. G.; Dyachkov, A. V.; Nenarokov, D. F.; Mukhin, L. M.</p> <p>1986-01-01</p> <p>The experiment on sulfuric acid <span class="hlt">aerosol</span> determination in the Venusian cloud <span class="hlt">layer</span> on board the Vega landers is described. An average content of sulfuric acid of approximately 1 mg/cu m was found for the samples taken from the atmosphere at <span class="hlt">heights</span> from 63 to 48 km and analyzed with the SIGMA-3 chromatograph. Sulfur dioxide (SO2) was revealed in the gaseous sample at the <span class="hlt">height</span> of 48 km. From the experimental results and blank run measurements, a suggestion is made that the Venusian cloud <span class="hlt">layer</span> <span class="hlt">aerosol</span> consists of more complicated particles than the sulfuric acid water solution does.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9680E..5NK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9680E..5NK"><span id="translatedtitle"><span class="hlt">Height</span> of <span class="hlt">layer</span> of intense turbulent heat exchange under conditions of stable atmospheric stratification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kamardin, A. P.; Nevzorova, I. V.; Odintsov, S. L.</p> <p>2015-11-01</p> <p>In the work, we consider estimates of the <span class="hlt">height</span> of <span class="hlt">layer</span> of intense turbulent heat exchange in stably stratified atmospheric boundary <span class="hlt">layer</span>, made with the use of meteorological acoustic radar (sodar). Dependence of this <span class="hlt">height</span> on temperature gradient is analyzed. Current temperature stratification of the atmosphere in the <span class="hlt">layer</span> with <span class="hlt">height</span> up to 1 000 m was determined with the help of MTP-5 meteorological temperature profiler.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A24C..03I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A24C..03I"><span id="translatedtitle">The Influence of Free Tropospheric <span class="hlt">Aerosol</span> on the Boundary <span class="hlt">Layer</span> <span class="hlt">Aerosol</span> Budget in the Arctic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Igel, A. L.; Ekman, A.; Leck, C.; Savre, J.; Tjernstrom, M. K. H.; Sedlar, J.</p> <p>2015-12-01</p> <p>Large-eddy simulations of the summertime high Arctic boundary <span class="hlt">layer</span> with mixed-phase stratus clouds have been performed based on observations taken during the ASCOS[1] campaign. The model includes a prognostic <span class="hlt">aerosol</span> scheme where accumulation mode <span class="hlt">aerosol</span> particles can be activated into cloud droplets, impaction scavenged, and regenerated upon cloud droplet evaporation or ice crystal sublimation. Two sets of simulations were performed, one with a constant <span class="hlt">aerosol</span> concentration in the boundary <span class="hlt">layer</span> and free troposphere, and one with enhanced free tropospheric concentrations based on observed <span class="hlt">aerosol</span> concentration profiles. We find that the rate of <span class="hlt">aerosol</span> depletion in the boundary <span class="hlt">layer</span> is an order of magnitude larger than the median surface emission rates measured over the open water, indicating that for the present case the surface emissions are unlikely to compensate for <span class="hlt">aerosol</span> loss due to interactions with clouds. In this case study, when the enhanced free troposphere <span class="hlt">aerosol</span> concentrations are included, the entrainment of these particles into the boundary <span class="hlt">layer</span> is able to offset the loss of particles from <span class="hlt">aerosol</span>-cloud interactions. These results suggest that enhanced levels of accumulation mode particles, if located at the cloud top, may be an important source of accumulation mode particles in the Arctic boundary <span class="hlt">layer</span>. [1] The Arctic Summer Cloud Ocean Study (ASCOS) was conducted in 2008 with the overall aim to improve our understanding of stratus cloud formation and possible climate feedback processes over the central Arctic Ocean. Tjernström et al., 2014 give more details.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.7726Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.7726Z"><span id="translatedtitle">Separating <span class="hlt">aerosol</span> microphysical effects and satellite measurement artifacts of the relationships between warm rain onset <span class="hlt">height</span> and <span class="hlt">aerosol</span> optical depth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Yannian; Rosenfeld, Daniel; Yu, Xing; Li, Zhanqing</p> <p>2015-08-01</p> <p>The high resolution (375 m) of the Visible Infrared Imaging Radiometer Suite on board the Suomi National Polar-Orbiting Partnership satellite allows retrieving relatively accurately the vertical evolution of convective cloud drop effective radius (re) with <span class="hlt">height</span> or temperature. A tight relationship is found over SE Asia and the adjacent seas during summer between the cloud-free <span class="hlt">aerosol</span> optical depth (AOD) and the cloud thickness required for the initiation of warm rain, as represented by the satellite-retrieved cloud droplet re of 14 µm, for a subset of conditions that minimize measurement artifacts. This cloud depth (ΔT14) is parameterized as the difference between the cloud base temperature and the temperature at the <span class="hlt">height</span> where re exceeds 14 µm (T14). For a unit increase of AOD, the <span class="hlt">height</span> of rain initiation is increased by about 5.5 km. The concern of data artifacts due to the increase in AOD near clouds was mitigated by selecting only scenes with cloud fraction (CF) < 0.1. For CF > 0.1 and ΔT14 > ~20°C, the increase of ΔT14 gradually levels off with further increase of AOD, possibly because the AOD is enhanced by <span class="hlt">aerosol</span> upward transport and detrainment through the clouds below the T14 isotherm. The bias in the retrieved re due to the different geometries of solar illumination was also quantified. It was shown that the retrievals are valid only for backscatter views or when avoiding scenes with significant amount of cloud self-shadowing. These artifacts might have contributed to past reported relationships between cloud properties and AOD.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19800050265&hterms=pollution+Marina&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpollution%2BMarina','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19800050265&hterms=pollution+Marina&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpollution%2BMarina"><span id="translatedtitle">The stratospheric sulfate <span class="hlt">aerosol</span> <span class="hlt">layer</span> - Processes, models, observations, and simulations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Whitten, R. C.; Toon, O. B.; Turco, R. P.</p> <p>1980-01-01</p> <p>After briefly reviewing the observational data on the stratospheric sulfate <span class="hlt">aerosol</span> <span class="hlt">layer</span>, the chemical and physical processes that are likely to fix the properties of the <span class="hlt">layer</span> are discussed. We present appropriate continuity equations for <span class="hlt">aerosol</span> particles, and show how to solve the equations on a digital computer. Simulations of the unperturbed <span class="hlt">aerosol</span> <span class="hlt">layer</span> by various published models are discussed and the sensitivity of <span class="hlt">layer</span> characteristics to variations in several <span class="hlt">aerosol</span> model parameters is studied. We discuss model applications to anthropogenic pollution problems and demonstrate that moderate levels of aerospace activity (supersonic transport and Space Shuttle operations) will probably have only a negligible effect on global climate. Finally, we evaluate the possible climatic effect of a ten-fold increase in the atmospheric abundance of carbonyl sulfide.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.2540Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.2540Y"><span id="translatedtitle">Composition and physical properties of the Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> and the North American Tropospheric <span class="hlt">Aerosol</span> <span class="hlt">Layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Pengfei; Toon, Owen B.; Neely, Ryan R.; Martinsson, Bengt G.; Brenninkmeijer, Carl A. M.</p> <p>2015-04-01</p> <p>Recent studies revealed <span class="hlt">layers</span> of enhanced <span class="hlt">aerosol</span> scattering in the upper troposphere and lower stratosphere over Asia (Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> (ATAL)) and North America (North American Tropospheric <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> (NATAL)). We use a sectional <span class="hlt">aerosol</span> model (Community <span class="hlt">Aerosol</span> and Radiation Model for Atmospheres (CARMA)) coupled with the Community Earth System Model version 1 (CESM1) to explore the composition and optical properties of these <span class="hlt">aerosol</span> <span class="hlt">layers</span>. The observed <span class="hlt">aerosol</span> extinction enhancement is reproduced by CESM1/CARMA. Both model and observations indicate a strong gradient of the sulfur-to-carbon ratio from Europe to the Asia on constant pressure surfaces. We found that the ATAL is mostly composed of sulfates, surface-emitted organics, and secondary organics; the NATAL is mostly composed of sulfates and secondary organics. The model also suggests that emission increases in Asia between 2000 and 2010 led to an increase of <span class="hlt">aerosol</span> optical depth of the ATAL by 0.002 on average which is consistent with observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.A33C0264L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.A33C0264L"><span id="translatedtitle">An automatic Planetary Boundary <span class="hlt">Layer</span> <span class="hlt">height</span> retrieval method with compact EZ backscattering Lidar in the frame of ICOS campaign</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Loaec, S.; Lolli, S.; Sauvage, L.; Boquet, M.; Xueref-Remy, I.</p> <p>2009-12-01</p> <p>Bigger strongly urbanized cities in the world are often exposed to atmospheric pollution events. To understand the chemical and physical processes that are taking place in these areas it is necessary to describe correctly the Planetary Boundary <span class="hlt">Layer</span> (PBL) dynamics and the PBL <span class="hlt">height</span> evolution. For these proposals, a compact and rugged eye safe UV Lidar, the EZLIDAR™, was developed together by CEA/LMD and LEOSPHERE (France) to study and investigate structural and optical properties of clouds and <span class="hlt">aerosols</span> and PBL time evolution. EZLIDAR™ has been validated by different remote and in-situ instruments as MPL Type-4 Lidar manufactured by NASA at ARM/SGP site or the LNA (Lidar Nuage <span class="hlt">Aerosol</span>) at the Laboratoire de Metereologie Dynamique LMD (France) and during several intercomparison campaigns. EZLIDAR™ algorithm retrieves automatically the PBL <span class="hlt">height</span> in real-time. The method is based on the detection of the slope of the signal linked to a sharp change in concentration of the <span class="hlt">aerosols</span>. Once detected, the different <span class="hlt">layers</span> are filtered on a 15mn sample and classified between nocturnal, convective or residual <span class="hlt">layer</span>, depending on the time and date. This method has been validated against those retrieved by the algorithm STRAT from data acquired at IPSL, France, showing 95% of correlation. In this paper are presented the results of the intercomparison campaign that took place in Orleans, France and Mace Head, Ireland in the framework of ICOS (Integrated Carbon Observation System) project, where the EZ Lidar™ worked under all weather conditions, clear sky, fog, low clouds, during the whole month of October 2008. Moreover, thanks to its 3D scanning capability, the EZLIDAR was able to provide the variability of the PBL <span class="hlt">height</span> around the site, enabling the scientists to estimate the flux intensities that play a key role in the radiative transfer budget and in the atmospheric pollutants dispersion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.A51B0342B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.A51B0342B"><span id="translatedtitle">Planetary Boundary <span class="hlt">Layer</span> (PBL) <span class="hlt">Heights</span> Derived From NASA Langley Airborne High Spectral Resolution Lidar (HSRL) Data Acquired During TexAQS/GoMACCS, CHAPS, and MILAGRO</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Cook, A.; Harper, D.; Obland, M. D.; Rogers, R. R.</p> <p>2007-12-01</p> <p>The NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL) was deployed on the NASA Langley B-200 King Air aircraft in the Mexico City metropolitan area during the Mega-city Initiative: Local and Global Research Observations (MILAGRO) campaign in March 2006; in the Houston metropolitan area during the Texas Air Quality Study (TexAQS)/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) in August and September 2006; and in the Oklahoma City area during Cumulus Humilis <span class="hlt">Aerosol</span> Processing Study (CHAPS) in June 2007. The HSRL instrument measures profiles of <span class="hlt">aerosol</span> extinction, backscatter and depolarization. The <span class="hlt">height</span> of the Planetary Boundary <span class="hlt">Layer</span> was derived by identifying sharp gradients in the HSRL 532-nm <span class="hlt">aerosol</span> backscatter signal profiles using an automated technique based on Brooks (2003) [I.M. Brooks, Finding Boundary <span class="hlt">Layer</span> Top: Application of Wavelet Covariance Transform to Lidar Backscatter Profiles. Journal of Atmospheric and Oceanic Technology 20, 1092-1105, 2003]. The technique uses a Haar wavelet covariance transform with multiple wavelet dilation values to adapt to non-ideal conditions where there can be gradients in the background signals and the boundary <span class="hlt">layer</span> can be ill defined. The technique also identifies the top and bottom of the transition (i.e. entrainment) zone. We have further modified the algorithm to find PBL <span class="hlt">heights</span> using HSRL backscatter data acquired during GoMACCS and MILAGRO, where complex terrain and overlying <span class="hlt">aerosol</span> <span class="hlt">layers</span> further complicate identifying the boundary <span class="hlt">layer</span>. In addition, PBL <span class="hlt">heights</span> are derived from HSRL backscatter data acquired during the CHAPS campaign, in another urban environment where the terrain is not as complex. We will describe the algorithm modifications we have made and show boundary <span class="hlt">layer</span> <span class="hlt">heights</span> and transition zone thicknesses for HSRL measurements over the Oklahoma City, Houston, and Mexico City areas during CHAPS, TexAQS/GoMACCS, and MILAGRO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A33B0141L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A33B0141L"><span id="translatedtitle">Spatiotemporal Variability in Observations of Urban Mixed-<span class="hlt">Layer</span> <span class="hlt">Heights</span> from Surface-based Lidar Systems during DISCOVER-AQ 2011</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lewis, J. R.; Banks, R. F.; Berkoff, T.; Welton, E. J.; Joseph, E.; Thompson, A. M.; Decola, P.; Hegarty, J. D.</p> <p>2015-12-01</p> <p>Accurate characterization of the planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> is crucial for numerical weather prediction, estimating pollution emissions and modeling air quality. More so, given the increasing trend in global urban populations, there is a growing need to improve our understanding of the urban boundary <span class="hlt">layer</span> structure and development. The Deriving Information on Surface conditions from COlumn and VERtically resolved observations relevant to Air Quality (DISCOVER-AQ) 2011 field campaign, which took place in the Baltimore-Washington DC region, offered a unique opportunity to study boundary <span class="hlt">layer</span> processes in an urban area using a geographically dense collection of surface-based lidar systems (see figure). Lidars use <span class="hlt">aerosols</span> as tracers for atmospheric boundary <span class="hlt">layer</span> dynamics with high vertical and temporal resolutions. In this study, we use data from two permanent Micropulse Lidar Network (MPLNET) sites and five field deployed Micropulse lidar (MPL) systems in order to observe spatiotemporal variations in the daytime mixed <span class="hlt">layer</span> <span class="hlt">height</span>. We present and compare lidar-derived retrievals of the mixed <span class="hlt">layer</span> <span class="hlt">height</span> using two different methods. The first method uses the wavelet covariance transform and a "fuzzy logic" attribution scheme in order to determine the mixed <span class="hlt">layer</span> <span class="hlt">height</span>. The second method uses an objective approach utilizing a time-adaptive extended Kalman filter. Independent measurements of the boundary <span class="hlt">layer</span> <span class="hlt">height</span> are obtained using profiles from ozonesonde launches at the Beltsville and Edgewood sites for comparison with lidar observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJWC.11924004V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJWC.11924004V"><span id="translatedtitle">Variability of Biomass Burning <span class="hlt">Aerosols</span> <span class="hlt">Layers</span> and Near Ground</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vasilescu, Jeni; Belegante, Livio; Marmureanu, Luminita; Toanca, Flori</p> <p>2016-06-01</p> <p>The aim of this study is to characterize <span class="hlt">aerosols</span> from both chemical and optical point of view and to explore the conditions to sense the same particles in elevated <span class="hlt">layers</span> and at the ground. Three days of continuous measurements using a multi-wavelength depolarization lidar(RALI) and a C-ToF-AMS <span class="hlt">aerosol</span> mass spectrometer are analyzed. The presence of smoke particles was assessed in low level <span class="hlt">layers</span> from RALI measurements. Chemical composition of submicronic volatile/semi-volatile <span class="hlt">aerosols</span> at ground level was monitored by the CTOF AMS Several episodes of biomass burning <span class="hlt">aerosols</span> have been identified by both techniques due to the presence of specific markers (f60, linear particle depolarization ratio, Ängström exponent).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.7832M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.7832M&link_type=ABSTRACT"><span id="translatedtitle">The seasonal cycle of the mixing <span class="hlt">layer</span> <span class="hlt">height</span> and its impact on black carbon concentrations in the Kathmandu Valley (Nepal)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mues, Andrea; Rupakheti, Maheswar; Hoor, Peter; Bozem, Heiko; Münkel, Christoph; Lauer, Axel; Butler, Tim</p> <p>2016-04-01</p> <p>The properties and the vertical structure of the mixing <span class="hlt">layer</span> as part of the planetary boundary <span class="hlt">layer</span> are of key importance for local air quality. They have a substantial impact on the vertical dispersion of pollutants in the lower atmosphere and thus on their concentrations near the surface. In this study, ceilometer measurements taken within the framework of the SusKat project (Sustainable Atmosphere for the Kathmandu Valley) are used to investigate the mixing <span class="hlt">layer</span> <span class="hlt">height</span> in the Kathmandu Valley, Nepal. The applied method is based on the assumption that the <span class="hlt">aerosol</span> concentration is nearly constant in the vertical and distinctly higher within the mixing <span class="hlt">layer</span> than in the air above. Thus, the <span class="hlt">height</span> with the steepest gradient within the ceilometer backscatter profile marks the top of the mixing <span class="hlt">layer</span>. Ceilometer and black carbon (BC) measurements conducted from March 2013 through February 2014 provide a unique and important dataset for the analysis of the meteorological and air quality conditions in the Kathmandu Valley. In this study the mean diurnal cycle of the mixing <span class="hlt">layer</span> <span class="hlt">height</span> in the Kathmandu Valley for each season (pre-monsoon, monsoon, post-monsoon and winter season) and its dependency on the meteorological situation is investigated. In addition, the impact of the mixing <span class="hlt">layer</span> <span class="hlt">height</span> on the BC concentration is analyzed and compared to the relevance of other important processes such as emissions, horizontal advection and deposition. In all seasons the diurnal cycle is typically characterized by low mixing <span class="hlt">heights</span> during the night, gradually increasing after sun rise reaching to maximum values in the afternoon before decreasing again. Seasonal differences can be seen particularly in the <span class="hlt">height</span> of the mixing <span class="hlt">layer</span>, e.g. from on average 153/1200 m (pre-monsoon) to 241/755 m (monsoon season) during the night/day, and the duration of enhanced mixing <span class="hlt">layer</span> <span class="hlt">heights</span> during daytime (around 12 hours (pre-monsoon season) to 8 hours (winter)). During the monsoon</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4651799','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4651799"><span id="translatedtitle">A Model Chain Application to Estimate Mixing <span class="hlt">Layer</span> <span class="hlt">Height</span> Related to PM10 Dispersion Processes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Guarnieri, F.; Calastrini, F.; Busillo, C.; Messeri, G.; Gozzini, B.</p> <p>2015-01-01</p> <p>The mixing <span class="hlt">layer</span> <span class="hlt">height</span> (MLH) is a crucial parameter in order to investigate the near surface concentrations of air pollutants. The MLH can be estimated by measurements of some atmospheric variables, by indirect estimates based on trace gases concentration or <span class="hlt">aerosol</span>, or by numerical models. Here, a modelling approach is proposed. The developed modelling system is based on the models WRF-ARW and CALMET. This system is applied on Firenze-Prato-Pistoia area (Central Italy), during 2010, and it is compared with in situ measurements. The aim of this work is to evaluate the use of MLH model estimates to characterize the critical episodes for PM10 in a limited area. In order to find out the meteorological conditions predisposing accumulation of PM10 in the atmosphere's lower level, some indicators are used: daily mean wind speed, cumulated rainfall, and mean MLH estimates from CALMET model. This indicator is linked to orography, which has important consequences on local weather dynamics. However, during critical events the local emission sources are crucial to the determination of threshold exceeding of PM10. Results show that the modelled MLH, together with cumulative rainfall and wind speed, can identify the meteorological conditions predisposing accumulation of air pollutant at ground level. PMID:26618190</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26618190','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26618190"><span id="translatedtitle">A Model Chain Application to Estimate Mixing <span class="hlt">Layer</span> <span class="hlt">Height</span> Related to PM10 Dispersion Processes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guarnieri, F; Calastrini, F; Busillo, C; Messeri, G; Gozzini, B</p> <p>2015-01-01</p> <p>The mixing <span class="hlt">layer</span> <span class="hlt">height</span> (MLH) is a crucial parameter in order to investigate the near surface concentrations of air pollutants. The MLH can be estimated by measurements of some atmospheric variables, by indirect estimates based on trace gases concentration or <span class="hlt">aerosol</span>, or by numerical models. Here, a modelling approach is proposed. The developed modelling system is based on the models WRF-ARW and CALMET. This system is applied on Firenze-Prato-Pistoia area (Central Italy), during 2010, and it is compared with in situ measurements. The aim of this work is to evaluate the use of MLH model estimates to characterize the critical episodes for PM10 in a limited area. In order to find out the meteorological conditions predisposing accumulation of PM10 in the atmosphere's lower level, some indicators are used: daily mean wind speed, cumulated rainfall, and mean MLH estimates from CALMET model. This indicator is linked to orography, which has important consequences on local weather dynamics. However, during critical events the local emission sources are crucial to the determination of threshold exceeding of PM10. Results show that the modelled MLH, together with cumulative rainfall and wind speed, can identify the meteorological conditions predisposing accumulation of air pollutant at ground level. PMID:26618190</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6733E..0BK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6733E..0BK"><span id="translatedtitle"><span class="hlt">Aerosol</span> model development for environmental monitoring in the coastal atmosphere surface <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaloshin, Gennady A.; Matvienko, Gennady G.</p> <p>2007-06-01</p> <p>Extinction of radiation in the marine boundary <span class="hlt">layer</span> is dominated by scattering and absorption due to atmospheric <span class="hlt">aerosol</span>. It is known, that the extinction of optical radiation visible and near IR spectra in the marine surface <span class="hlt">layer</span> is determined mainly by scattering and absorption atmospheric <span class="hlt">aerosol</span>. It influences on a dependence of spectral transmission and extinction both natural, and artificial light that is of interest for a wide range of problems, in particular for radiating problems at studying laws of climate formation, and for lines of the applications connected to the forecast of a signal power in coastal conditions at an estimation of EO systems characteristics. This is important to optical retrievals from satellite, remote sensing at environmental monitoring, backscatter of light to space (including climate forcing), cloud properties etc. In unpolluted regions the greatest effects on near shore scattering extinction will be a result of sea-salt from breaking waves and variations in relative humidity. The role of breaking waves appears to be modulated by wind, tide, swell, wave spectra and coastal conditions. These influences will be superimposed upon <span class="hlt">aerosol</span> generated by open ocean sea-salt <span class="hlt">aerosol</span> that varies with wind speed. The focus of our study is the extinction and optical effects due to <span class="hlt">aerosol</span> in a specific coastal region. This involves linking coastal physical properties to oceanic and meteorological parameters in order to develop predictive algorithms that describe 3-D <span class="hlt">aerosol</span> structure and variability. The <span class="hlt">aerosol</span> microphysical model of the marine and coastal atmosphere surface <span class="hlt">layer</span> is considered. The model distinctive feature is parameterization of amplitude and width of the modes as functions of fetch and wind speed. In the paper the dN/dr behavior depending at change meteorological parameters, <span class="hlt">heights</span> above sea level, fetch, wind speed and RH is show. On the basis of the developed model with usage of Mie theory for spheres the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713684S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713684S"><span id="translatedtitle">Global <span class="hlt">aerosol</span> modeling with the online NMMB/BSC Chemical Transport Model: sensitivity to fire injection <span class="hlt">height</span> prescription and secondary organic <span class="hlt">aerosol</span> schemes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spada, Michele; Jorba, Oriol; Pérez García-Pando, Carlos; Tsigaridis, Kostas; Soares, Joana; Obiso, Vincenzo; Janjic, Zavisa; Baldasano, Jose M.</p> <p>2015-04-01</p> <p>We develop and evaluate a fully online-coupled model simulating the life-cycle of the most relevant global <span class="hlt">aerosols</span> (i.e. mineral dust, sea-salt, black carbon, primary and secondary organic <span class="hlt">aerosols</span>, and sulfate) and their feedbacks upon atmospheric chemistry and radiative balance. Following the capabilities of its meteorological core, the model has been designed to simulate both global and regional scales with unvaried parameterizations: this allows detailed investigation on the <span class="hlt">aerosol</span> processes bridging the gap between global and regional models. Since the strong uncertainties affecting <span class="hlt">aerosol</span> models are often unresponsive to model complexity, we choose to introduce complexity only when it clearly improves results and leads to a better understanding of the simulated <span class="hlt">aerosol</span> processes. We test two important sources of uncertainty - the fires injection <span class="hlt">height</span> and secondary organic <span class="hlt">aerosol</span> (SOA) production - by comparing a baseline simulation with experiments using more advanced approaches. First, injection <span class="hlt">heights</span> prescribed by Dentener et al. (2006, ACP) are compared with climatological injection <span class="hlt">heights</span> derived from satellite measurements and produced through the Integrated Monitoring and Modeling System For Wildland Fires (IS4FIRES). Also global patterns of SOA produced by the yield conversion of terpenes as prescribed by Dentener et al. (2006, ACP) are compared with those simulated by the two-product approach of Tsigaridis et al. (2003, ACP). We evaluate our simulations using a variety of observations and measurement techniques. Additionally, we discuss our results in comparison to other global models within AEROCOM and ACCMIP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012BoLMe.143..189P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012BoLMe.143..189P&link_type=ABSTRACT"><span id="translatedtitle">Measurements and Parametrizations of the Atmospheric Boundary-<span class="hlt">Layer</span> <span class="hlt">Height</span> at Dome C, Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pietroni, Ilaria; Argentini, Stefania; Petenko, Igor; Sozzi, Roberto</p> <p>2012-04-01</p> <p>An experimental campaign, Study of the Atmospheric Boundary <span class="hlt">Layer</span> Environmental at Dome C, was held during 2005 at the French-Italian station of Concordia at Dome C. Ground-based remote sensors, as well as in situ instrumentation, were used during the experimental campaign. The measurements allowed the direct estimation of the polar atmospheric boundary-<span class="hlt">layer</span> <span class="hlt">height</span> and the test of several parametrizations for the unstable and stable boundary <span class="hlt">layers</span>. During the months of January and February, weak convection was observed while, during the polar night, a long-lived stable boundary <span class="hlt">layer</span> occurred continuously. Under unstable stratification the mixing-<span class="hlt">layer</span> <span class="hlt">height</span> was determined using the sodar backscattered echoes and potential temperature profiles. The two estimations are highly correlated, with the mixing <span class="hlt">height</span> ranging between 30 and 350 m. A simple prognostic one-dimensional model was used to estimate the convective mixing-<span class="hlt">layer</span> <span class="hlt">height</span>, with the correlation coefficient between observations and model results being 0.66. The boundary-<span class="hlt">layer</span> <span class="hlt">height</span> under stable conditions was estimated from radiosounding profiles as the <span class="hlt">height</span> where the critical Richardson number is reached; values between 10 and 150 m were found. A visual inspection of potential temperature profiles was also used as further confirmation of the experimental <span class="hlt">height</span>; the results of the two methods are in good agreement. Six parametrizations from the literature for the stable boundary-<span class="hlt">layer</span> <span class="hlt">height</span> were tested. Only the parametrization that considers the long-lived stable boundary <span class="hlt">layer</span> and takes into account the interaction of the stable <span class="hlt">layer</span> with the free atmosphere is in agreement with the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8534E..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8534E..08S"><span id="translatedtitle">Results from long-term detection of mixing <span class="hlt">layer</span> <span class="hlt">height</span>: ceilometer and comparison with Radio-Acoustic Sounding System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schäfer, Klaus; Emeis, Stefan; Jahn, Carsten; Tuma, Michael; Münkel, Christoph; Suppan, Peter</p> <p>2012-11-01</p> <p>The mixing <span class="hlt">layer</span> <span class="hlt">height</span> (MLH) is an important factor which influences exchange processes of ground level emissions. The continuous knowledge of MLH is supporting the understanding of processes directing air quality. If the MLH is located near to the ground, which occurs mainly during winter and night-time, air pollution can be high due to a strongly limited air mass dilution. Since 2006 different methods for long-term continuous remote sensing of mixing <span class="hlt">layer</span> <span class="hlt">height</span> (MLH) are operated in Augsburg. The Vaisala ceilometers LD40 and CL31 are used which are eye-safe commercial mini-lidar systems. The ceilometer measurements provide information about the range-dependent <span class="hlt">aerosol</span> concentration; gradient minima within this profile mark the borders of mixed <span class="hlt">layers</span>. Special software for these ceilometers provides routine retrievals of lower atmosphere <span class="hlt">layering</span> from vertical profiles of laser backscatter data. The radiosonde data from the station Oberschleissheim near Munich (about 50 km away from Augsburg city) are also used for MLH determination. The profile behavior of relative humidity (strong decrease) and virtual potential temperature (inversion) of the radiosonde agree mostly well with the MLH indication from ceilometer laser backscatter density gradients. A RASS (Radio-Acoustic Sounding System) from Metek is applied which detects the <span class="hlt">height</span> of a turbulent <span class="hlt">layer</span> characterized by high acoustic backscatter intensities due to thermal fluctuations and a high variance of the vertical velocity component as well as the vertical temperature profile from the detection of acoustic signal propagation and thus temperature inversions which mark atmospheric <span class="hlt">layers</span>. These data of RASS measurements are the input for a software-based determination of MLH. A comparison of the results of the remote sensing methods during simultaneous measurements was performed. The information content of the different remote sensing instruments for MLH in dependence from different weather classes was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006IzAOP..42..715K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006IzAOP..42..715K"><span id="translatedtitle">Influence of a high <span class="hlt">aerosol</span> concentration on the thermal structure of the atmospheric boundary <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khaikin, M. N.; Kuznetsova, I. N.; Kadygrov, E. N.</p> <p>2006-12-01</p> <p>The influence of increased concentrations of submicron <span class="hlt">aerosol</span> produced by forest fires on thermal characteristics of the atmospheric boundary <span class="hlt">layer</span> (ABL) in Moscow and its remote vicinity (the town of Zvenigorod) are analyzed on the basis of regular remote measurements of the ABL temperature profile with the use of MTP-5 profilers. In the air basin of a large city, additional <span class="hlt">aerosol</span> and accompanying pollutants in early morning hours (at small <span class="hlt">heights</span> of the Sun) most frequently did not cause substantial changes in the ABL thermal structure. In the locality remote from the megalopolis (Zvenigorod), the atmospheric pollution by <span class="hlt">aerosol</span> led to noticeable changes in the ABL thermal characteristics. Especially strong changes were observed in the daytime, during the maximum supply of solar radiation. In morning hours, the heating rate of the lower 100-m <span class="hlt">layer</span> of the polluted air exceeded the heating rate of a relatively pure air by more than one degree. In higher <span class="hlt">layers</span>, the differences between the rates of temperature changes in a relatively clean atmosphere and in an atmosphere polluted by <span class="hlt">aerosol</span> (in the suburb) were insignificant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRD..121..336B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRD..121..336B"><span id="translatedtitle">The Two-Column <span class="hlt">Aerosol</span> Project: Phase I—Overview and impact of elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> on <span class="hlt">aerosol</span> optical depth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berg, Larry K.; Fast, Jerome D.; Barnard, James C.; Burton, Sharon P.; Cairns, Brian; Chand, Duli; Comstock, Jennifer M.; Dunagan, Stephen; Ferrare, Richard A.; Flynn, Connor J.; Hair, Johnathan W.; Hostetler, Chris A.; Hubbe, John; Jefferson, Anne; Johnson, Roy; Kassianov, Evgueni I.; Kluzek, Celine D.; Kollias, Pavlos; Lamer, Katia; Lantz, Kathleen; Mei, Fan; Miller, Mark A.; Michalsky, Joseph; Ortega, Ivan; Pekour, Mikhail; Rogers, Ray R.; Russell, Philip B.; Redemann, Jens; Sedlacek, Arthur J.; Segal-Rosenheimer, Michal; Schmid, Beat; Shilling, John E.; Shinozuka, Yohei; Springston, Stephen R.; Tomlinson, Jason M.; Tyrrell, Megan; Wilson, Jacqueline M.; Volkamer, Rainer; Zelenyuk, Alla; Berkowitz, Carl M.</p> <p>2016-01-01</p> <p>The Two-Column <span class="hlt">Aerosol</span> Project (TCAP), conducted from June 2012 through June 2013, was a unique study designed to provide a comprehensive data set that can be used to investigate a number of important climate science questions, including those related to <span class="hlt">aerosol</span> mixing state and <span class="hlt">aerosol</span> radiative forcing. The study was designed to sample the atmosphere between and within two atmospheric columns; one fixed near the coast of North America (over Cape Cod, MA) and a second moveable column over the Atlantic Ocean several hundred kilometers from the coast. The U.S. Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) was deployed at the base of the Cape Cod column, and the ARM Aerial Facility was utilized for the summer and winter intensive observation periods. One important finding from TCAP is that four of six nearly cloud-free flight days had <span class="hlt">aerosol</span> <span class="hlt">layers</span> aloft in both the Cape Cod and maritime columns that were detected using the nadir pointing second-generation NASA high-spectral resolution lidar (HSRL-2). These <span class="hlt">layers</span> contributed up to 60% of the total observed <span class="hlt">aerosol</span> optical depth (AOD). Many of these <span class="hlt">layers</span> were also intercepted by the aircraft configured for in situ sampling, and the <span class="hlt">aerosol</span> in the <span class="hlt">layers</span> was found to have increased amounts of biomass burning material and nitrate compared to <span class="hlt">aerosol</span> found near the surface. In addition, while there was a great deal of spatial and day-to-day variability in the <span class="hlt">aerosol</span> chemical composition and optical properties, no systematic differences between the two columns were observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1612198D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1612198D"><span id="translatedtitle">Anthropogenic <span class="hlt">Aerosol</span> Effects on Sea Surface Temperatures: Mixed-<span class="hlt">Layer</span> Ocean Experiments with Explicit <span class="hlt">Aerosol</span> Representation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dallafior, Tanja; Folini, Doris; Wild, Martin; Knutti, Reto</p> <p>2014-05-01</p> <p>Anthropogenic <span class="hlt">aerosols</span> affect the Earth's radiative balance both through direct and indirect effects. These effects can lead to a reduction of the incoming solar radiation at the surface, i.e. dimming, which may lead to a change in sea surface temperatures (SST) or SST pattern. This, in turn, may affect precipitation patterns. The goal of the present work is to achieve an estimate of the equilibrium SST changes under anthropogenic <span class="hlt">aerosol</span> forcing since industrialisation. We show preliminary results from mixed-<span class="hlt">layer</span> ocean (MLO) experiments with explicit <span class="hlt">aerosol</span> representation performed with ECHAM6-HAM. The (fixed) MLO heat flux into the deep ocean was derived from atmosphere only runs with fixed climatological SSTs (1961-1990 average) and present day (year 2000) <span class="hlt">aerosols</span> and GHG burdens. Some experiments we repeated with an alternative MLO deep ocean heat flux (based on pre-industrial conditions) to test the robustness of our results with regard to this boundary condition. The maximum surface temperature responses towards anthropogenic <span class="hlt">aerosol</span> and GHG forcing (separately and combined) were derived on a global and regional scale. The same set of experiments was performed with <span class="hlt">aerosol</span> and GHG forcings representative of different decades over the past one and a half centuries. This allows to assess how SST patterns at equilibrium changed with changing <span class="hlt">aerosol</span> (and GHG) forcing. Correlating SST responses with the change in downward clear-sky and all-sky shortwave radiation provides a first estimate of the response to anthropogenic <span class="hlt">aerosols</span>. Our results show a clear contrast in hemispheric surface temperature response, as expected from the inter-hemispheric asymmetry of <span class="hlt">aerosol</span> forcing The presented work is part of a project aiming at quantifying the effect of anthropogenic <span class="hlt">aerosol</span> forcing on SSTs and the consequences for global precipitation patterns. Results from this study will serve as a starting point for further experiments involving a dynamic ocean model, which</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.7936S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.7936S&link_type=ABSTRACT"><span id="translatedtitle">Elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> and their radiative impact over Kanpur during monsoon onset period</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sarangi, Chandan; Tripathi, S. N.; Mishra, A. K.; Goel, A.; Welton, E. J.</p> <p>2016-07-01</p> <p>Accurate information about <span class="hlt">aerosol</span> vertical distribution is needed to reduce uncertainties in <span class="hlt">aerosol</span> radiative forcing and its effect on atmospheric dynamics. The present study deals with synergistic analyses of <span class="hlt">aerosol</span> vertical distribution and <span class="hlt">aerosol</span> optical depth (AOD) with meteorological variables using multisatellite and ground-based remote sensors over Kanpur in central Indo-Gangetic Plain (IGP). Micro-Pulse Lidar Network-derived <span class="hlt">aerosol</span> vertical extinction (σ) profiles are analyzed to quantify the interannual and daytime variations during monsoon onset period (May-June) for 2009-2011. The mean <span class="hlt">aerosol</span> profile is broadly categorized into two <span class="hlt">layers</span> viz., a surface <span class="hlt">layer</span> (SL) extending up to 1.5 km (where σ decreased exponentially with <span class="hlt">height</span>) and an elevated <span class="hlt">aerosol</span> <span class="hlt">layer</span> (EAL) extending between 1.5 and 5.5 km. The increase in total columnar <span class="hlt">aerosol</span> loading is associated with relatively higher increase in contribution from EAL loading than that from SL. The mean contributions of EALs are about 60%, 51%, and 50% to total columnar AOD during 2009, 2010, and 2011, respectively. We observe distinct parabolic EALs during early morning and late evening but uniformly mixed EALs during midday. The interannual and daytime variations of EALs are mainly influenced by long-range transport and convective capacity of the local emissions, respectively. Radiative flux analysis shows that clear-sky incoming solar radiation at surface is reduced with increase in AOD, which indicates significant cooling at surface. Collocated analysis of atmospheric temperature and <span class="hlt">aerosol</span> loading reveals that increase in AOD not only resulted in surface dimming but also reduced the temperature (˜2-3°C) of lower troposphere (below 3 km altitude). Radiative transfer simulations indicate that the reduction of incoming solar radiation at surface is mainly due to increased absorption by EALs (with increase in total AOD). The observed cooling in lower troposphere in high <span class="hlt">aerosol</span> loading</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110011720&hterms=Too+Asian&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DToo%2BAsian','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110011720&hterms=Too+Asian&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DToo%2BAsian"><span id="translatedtitle">CALIPSO Detection of an Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vemier, J.-P.; Thomason, L. W.; Kar, J.</p> <p>2011-01-01</p> <p>The first four years of the CALIPSO lidar measurements have revealed the existence of an <span class="hlt">aerosol</span> <span class="hlt">layer</span> at the tropopause level associated with the Asian monsoon season in June, July and August. This Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> (ATAL) extends geographically from Eastern Mediterranean (down to North Africa) to Western China (down to Thailand), and vertically from 13 to 18 km. The Scattering Ratio inferred from CALIPSO shows values between 1.10. 1.15 on average with associated depolarization ratio of less than 5%. The Gaussian distribution of the points indicates that the mean value is statistically driven by an enhancement of the background <span class="hlt">aerosol</span> level and not by episodic events such as a volcanic eruption or cloud contamination. Further satellite observations of <span class="hlt">aerosols</span> and gases as well as field campaigns are urgently needed to characterize this <span class="hlt">layer</span>, which is likely to be a significant source of non-volcanic <span class="hlt">aerosols</span> for the global upper troposphere with a potential impact on its radiative and chemical balance</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8177E..08M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8177E..08M"><span id="translatedtitle">Adding confidence levels and error bars to mixing <span class="hlt">layer</span> <span class="hlt">heights</span> detected by ceilometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Münkel, Christoph; Schäfer, Klaus; Emeis, Stefan</p> <p>2011-11-01</p> <p>Eye-safe lidar ceilometers are reliable tools for unattended boundary <span class="hlt">layer</span> structure monitoring around the clock. A single lens optical design enables precise assessment of inversion <span class="hlt">layers</span> and nocturnal stable <span class="hlt">layers</span> below 200 m. This design has been chosen for the Vaisala Ceilometers CL31 and CL51. Based on the gradient method, an automatic algorithm for online retrieval of boundary <span class="hlt">layer</span> depth and additional residual structures has been developed. This robust all weather algorithm is part of the Vaisala boundary <span class="hlt">layer</span> reporting and analysis tool BL-VIEW. The data averaging intervals used depend on range and signal noise; detection thresholds vary with signal amplitude. All <span class="hlt">layer</span> <span class="hlt">heights</span> reported are accomponied by a quality index. In most cases the lowest of these <span class="hlt">layers</span> is a good measure for the mixing <span class="hlt">layer</span> <span class="hlt">height</span>. The continuous knowledge of this atmospheric parameter is supporting the understanding of processes directing air quality. The utility of mixing <span class="hlt">layer</span> <span class="hlt">height</span> values for air quality forecast can be further increased by additionally utilizing unaveraged profiles for gradient minima detection. Based on their variation from the result of the BL-VIEW algorithm, confidence levels and error bars can be calculated. Results are presented from campaigns at three different sites. Validation with mixing <span class="hlt">layer</span> <span class="hlt">height</span> values derived from co-located radiosoundings confirm the applicability of this novel method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.A51A0054P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.A51A0054P"><span id="translatedtitle">Estimating the stratocumulus-topped marine boundary <span class="hlt">layer</span>'s <span class="hlt">height</span> using wind profilers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piña, A.; Hartten, L. M.; Bianco, L.</p> <p>2010-12-01</p> <p>Stratocumulus clouds frequently form over the cold water of the southeastern Pacific Ocean (SEP). Large in area, they affect the Earth’s energy budget by blocking and reflecting solar radiation. In this region of atmospheric stability, the <span class="hlt">height</span> of the boundary <span class="hlt">layer</span> is at about the same elevation as the top of the stratus deck. In the fall of 2000, a 915-MHz wind profiler was mounted on the R/V Ronald H. Brown to obtain information about the depth of the stratocumulus-topped marine boundary <span class="hlt">layer</span> at different times and locations. With the tandem of cloud-top <span class="hlt">heights</span> and ceilometer data (<span class="hlt">heights</span> of the cloud bases), cloud depth can be determined in order to draw further conclusions on the Earth’s radiation budget; however, estimating the <span class="hlt">height</span> of the stratocumulus-topped marine boundary <span class="hlt">layer</span> was the scope for this research. Data from daily <span class="hlt">height</span>-vs-time plots of relevant profiler variables (reflectivity, vertical velocity, and spectral width) for different locations during the cruise in the SEP—near the equator, near the ITCZ, and in the stratocumulus region—were examined. The plots showed data that did not seem to be atmospheric, so a procedure to clean up non-atmospheric data was implemented. The adjusted data were then inserted into a modified version of the Bianco et al. (2008) boundary <span class="hlt">layer</span> <span class="hlt">height</span> algorithm. Estimated <span class="hlt">heights</span> for the marine boundary <span class="hlt">layer</span> appeared to vary between the surface of the Earth and 1500m. The algorithm was originally designed for convective boundary <span class="hlt">layers</span>. The near-surface <span class="hlt">heights</span> are probably erroneous, an artifact of data characteristics expected by the algorithm. The higher, more plausible <span class="hlt">heights</span> will also need further verification.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016tac..workE..14S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016tac..workE..14S"><span id="translatedtitle"><span class="hlt">Aerosols</span> optical propertites in Titan's Detached Haze <span class="hlt">Layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seignovert, Benoît; Rannou, Pascal; Lavvas, Panayotis; Cours, Thibaud; West, Robert A.</p> <p>2016-06-01</p> <p>Titan's Detached Haze <span class="hlt">Layer</span> (DHL) first observed in 1983 by Rages and Pollack during the Voyager 2 [1] is a consistent spherical haze feature surrounding Titan's upper atmosphere and detached from the main haze. Since 2005, the Imaging Science Subsystem (ISS) instrument on board the Cassini mission performs a continuous survey of the Titan's atmosphere and confirmed its persistence at 500 km up to the equinox (2009) before its drop and disappearance in 2012 [2]. Previous analyses showed, that this <span class="hlt">layer</span> corresponds to the transition area between small spherical <span class="hlt">aerosols</span> and large fractal aggregates and play a key role in the <span class="hlt">aerosols</span> formation in Titan's atmosphere [3-5]. In this study we perform UV photometric analyses on ISS observations taken from 2005 to 2007 based on radiative transfer inversion to retrieve <span class="hlt">aerosols</span> particles properties in the DHL (bulk and monomer size, fractal dimension and local density).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGeod..85..637B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGeod..85..637B"><span id="translatedtitle">Simulation study of the influence of the ionospheric <span class="hlt">layer</span> <span class="hlt">height</span> in the thin <span class="hlt">layer</span> ionospheric model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brunini, Claudio; Camilion, Emilio; Azpilicueta, Francisco</p> <p>2011-09-01</p> <p>This work aims to contribute to the understanding of the influence of the ionospheric <span class="hlt">layer</span> <span class="hlt">height</span> (ILH) on the thin <span class="hlt">layer</span> ionospheric model (TLIM) used to retrieve ionospheric information from the GNSS observations. Particular attention is paid to the errors caused on the estimation of the vertical total electron content ( vTEC) and the GNSS satellites and receivers inter-frequency biases (IFB), by the use of an inappropriate ILH. The work relies upon numerical simulations performed with an empirical model of the Earth's ionosphere: the model is used to create realistic but controlled ionospheric scenarios and the errors are evaluated after recovering those scenarios with the TLIM. The error assessment is performed in the Central and the northern part of the South American continents, a region where large errors are expected due to the combined actions of the Appleton Anomaly of the ionosphere and the South-Atlantic anomaly of the geomagnetic field. According to this study, there does not exist a unique ILH that cancels the vTEC error for the whole region under consideration. The ILH that cancels the regional mean vTEC error varies with the solar activity and season. The latitude-dependent conversion error propagates to the parameters of the model used to represent the latitudinal variation on the vTEC on the ionospheric <span class="hlt">layer</span>, and to the IFB, when these values are simultaneously estimated from the observed sTEC. Besides, the ILH that cancels the regional mean vTEC error is different from the one that cancels the IFB error and the difference between both ILH varies with the solar activity and season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1097330','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1097330"><span id="translatedtitle">Lidar Investigation of Tropical Nocturnal Boundary <span class="hlt">Layer</span> <span class="hlt">Aerosols</span> and Cloud Macrophysics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Manoj, M. G.; Devara, PC S.; Taraphdar, Sourav</p> <p>2013-10-01</p> <p>Observational evidence of two-way association between nocturnal boundary <span class="hlt">layer</span> <span class="hlt">aerosols</span> and cloud macrophysical properties under different meteorological conditions is reported in this paper. The study has been conducted during 2008-09 employing a high space-time resolution polarimetric micro-pulse lidar over a tropical urban station in India. Firstly, the study highlights the crucial role of boundary <span class="hlt">layer</span> <span class="hlt">aerosols</span> and background meteorology on the formation and structure of low-level stratiform clouds in the backdrop of different atmospheric stability conditions. Turbulent mixing induced by the wind shear at the station, which is associated with a complex terrain, is found to play a pivotal role in the formation and structural evolution of nocturnal boundary <span class="hlt">layer</span> clouds. Secondly, it is shown that the trapping of energy in the form of outgoing terrestrial radiation by the overlying low-level clouds can enhance the <span class="hlt">aerosol</span> mixing <span class="hlt">height</span> associated with the nocturnal boundary <span class="hlt">layer</span>. To substantiate this, the long-wave heating associated with cloud capping has been quantitatively estimated in an indirect way by employing an Advanced Research Weather Research and Forecasting (WRF-ARW) model version 2.2 developed by National Center for Atmospheric Research (NCAR), Colorado, USA, and supplementary data sets; and differentiated against other heating mechanisms. The present investigation as well establishes the potential of lidar remote-sensing technique in exploring some of the intriguing aspects of the cloud-environment relationship.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A31B3033R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A31B3033R"><span id="translatedtitle">Global Measurement of Junge <span class="hlt">Layer</span> Stratospheric <span class="hlt">Aerosol</span> with OMPS/LP. Scattering Properties and Particle Size</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rault, D. F.; Bhartia, P. K.</p> <p>2014-12-01</p> <p>The OMPS/LP was launched on board the NPP space platform in October 2011. Over the past two years, the OMPS/LP was used to retrieve the global distribution of ozone and <span class="hlt">aerosol</span>. The paper will describe the <span class="hlt">aerosol</span> product, which NASA is presently preparing for public release. The current OMPS/LP <span class="hlt">aerosol</span> product consists of latitude-altitude curtains along the NPP Sun-synchronous orbit, from cloud top to about 40 km. These curtains extend from local sunrise in Southern polar region to local sunset in Northern polar region. <span class="hlt">Aerosol</span> extinctions are produced at five distinct wavelengths, namely 513, 525, 670, 750 and 870 nm, with a sampling of 1 km in vertical direction and 1 degree latitude in the along-track direction. The OMPS/LP <span class="hlt">aerosol</span> dataset is fairly large, with 7000 vertical profiles produced each day for each wavelength. The <span class="hlt">aerosol</span> product will be presented in terms of extinction monthly median values and mean Angstrom coefficient (particle size). Over the past two years, the Junge <span class="hlt">layer</span> was affected by several events such as volcanic eruptions (Nabro and Kelut) and a meteor (Chelyabinsk), the effects of which are clearly visible in the OMPS/LP dataset. The Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> (ATAL) can also be observed in the OMPS/LP dataset. Moreover the effect of the Brewer Dobson Circulation (BDC) can be observed at high altitudes: the BDC velocity at 35 km can be estimated from the time variation of iso-density <span class="hlt">heights</span> and was found to compare well with BDC velocities evaluated with the water vapor tape recorder technique as well as MERRA model values. Finally, <span class="hlt">aerosol</span> filaments are clearly visible in OMPS/LP <span class="hlt">aerosol</span> dataset as they appear as distinct "bubbles" on the OMPS/LP curtain files at periodic intervals in both the Southern and Northern hemispheres. These filaments are a main source of transport from tropical to polar region, and OMPS/LP data can therefore be instrumental in quantifying the rate of this transport. The quality of the OMPS/LP <span class="hlt">aerosol</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17695910','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17695910"><span id="translatedtitle">On the source of organic acid <span class="hlt">aerosol</span> <span class="hlt">layers</span> above clouds.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sorooshian, Armin; Lu, Miao-Ling; Brechtel, Fred J; Jonsson, Haflidi; Feingold, Graham; Flagan, Richard C; Seinfeld, John H</p> <p>2007-07-01</p> <p>During the July 2005 Marine Stratus/Stratocumulus Experiment (MASE) and the August-September 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS), the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter probed <span class="hlt">aerosols</span> and cumulus clouds in the eastern Pacific Ocean off the coast of northern California and in southeastern Texas, respectively. An on-board particle-into-liquid sampler (PILS) quantified inorganic and organic acid species with < or = 5-min time resolution. Ubiquitous organic <span class="hlt">aerosol</span> <span class="hlt">layers</span> above cloud with enhanced organic acid levels were observed in both locations. The data suggest that aqueous-phase reactions to produce organic acids, mainly oxalic acid, followed by droplet evaporation is a source of elevated organic acid <span class="hlt">aerosol</span> levels above cloud. Oxalic acid is observed to be produced more efficiently relative to sulfate as the cloud liquid water content increases, corresponding to larger and less acidic droplets. As derived from large eddy simulations of stratocumulus underthe conditions of MASE, both Lagrangian trajectory analysis and diurnal cloudtop evolution provide evidence that a significant fraction of the <span class="hlt">aerosol</span> mass concentration above cloud can be accounted for by evaporated droplet residual particles. Methanesulfonate data suggest that entrainment of free tropospheric <span class="hlt">aerosol</span> can also be a source of organic acids above boundary <span class="hlt">layer</span> clouds. PMID:17695910</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1134522','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1134522"><span id="translatedtitle">Comparison of Mixed <span class="hlt">Layer</span> <span class="hlt">Heights</span> from Airborne High Spectral Resolution Lidar, Ground-based Measurements, and the WRP-Chem Model during CalNex and CARES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Scarino, Amy Jo; Obland, Michael; Fast, Jerome D.; Burton, S. P.; Ferrare, R. A.; Hostetler, Chris A.; Berg, Larry K.; Lefer, Barry; Haman, C.; Hair, John; Rogers, Ray; Butler, Carolyn; Cook, A. L.; Harper, David</p> <p>2014-06-05</p> <p>The California Research at the Nexus of Air Quality and Climate Change (CalNex) and Carbonaceous <span class="hlt">Aerosol</span> and Radiative Effects Study (CARES) field campaigns during May and June 2010 provided a data set appropriate for studying characteristics of the planetary boundary <span class="hlt">layer</span> (PBL). The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) was deployed to California onboard the NASA LaRC B-200 aircraft to aid incharacterizing <span class="hlt">aerosol</span> properties during these two field campaigns. Measurements of <span class="hlt">aerosol</span> extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) profiles during 31 flights, many in coordination with other research aircraft and ground sites, constitute a diverse data set for use in characterizing the spatial and temporal distribution of <span class="hlt">aerosols</span>, as well as the depth and variability of the daytime mixed <span class="hlt">layer</span> (ML), which is a subset within the PBL. This work illustrates the temporal and spatial variability of the ML in the vicinity of Los Angeles and Sacramento, CA. ML <span class="hlt">heights</span> derived from HSRL measurements are compared to PBL <span class="hlt">heights</span> derived from radiosonde profiles, ML <span class="hlt">heights</span> measured from ceilometers, and simulated PBL <span class="hlt">heights</span> from the Weather Research and Forecasting Chemistry (WRF-Chem) community model. Comparisons between the HSRL ML <span class="hlt">heights</span> and the radiosonde profiles in Sacramento result in a correlation coefficient value (R) of 0.93 (root7 mean-square (RMS) difference of 157 m and bias difference (HSRL radiosonde) of 5 m). HSRL ML <span class="hlt">heights</span> compare well with those from the ceilometer in the LA Basin with an R of 0.89 (RMS difference of 108 m and bias difference (HSRL Ceilometer) of -9.7 m) for distances of up to 30 km between the B-200 flight track and the ceilometer site. Simulated PBL <span class="hlt">heights</span> from WRF-Chem were compared with those obtained from all flights for each campaign, producing an R of 0.58 (RMS difference of 604 m and a bias difference (WRF-Chem HSRL) of -157 m) for CalNex and 0</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.9951Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.9951Z&link_type=ABSTRACT"><span id="translatedtitle">Planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> from CALIOP compared to radiosonde over China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Wanchun; Guo, Jianping; Miao, Yucong; Liu, Huan; Zhang, Yong; Li, Zhengqiang; Zhai, Panmao</p> <p>2016-08-01</p> <p>Accurate estimation of planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> (PBLH) is key to air quality prediction, weather forecast, and assessment of regional climate change. The PBLH retrieval from the Cloud-<span class="hlt">Aerosol</span> Lidar with Orthogonal Polarization (CALIOP) is expected to complement ground-based measurements due to the broad spatial coverage of satellites. In this study, CALIOP PBLHs are derived from combination of Haar wavelet and maximum variance techniques, and are further validated against PBLHs estimated from ground-based lidar at Beijing and Jinhua. Correlation coefficients between PBLHs from ground- and satellite-based lidars are 0.59 at Beijing and 0.65 at Jinhua. Also, the PBLH climatology from CALIOP and radiosonde are compiled over China during the period from 2011 to 2014. Maximum CALIOP-derived PBLH can be seen in summer as compared to lower values in other seasons. Three matchup scenarios are proposed according to the position of each radiosonde site relative to its closest CALIPSO ground tracks. For each scenario, intercomparisons were performed between CALIOP- and radiosonde-derived PBLHs, and scenario 2 is found to be better than other scenarios using difference as the criteria. In early summer afternoon over 70 % of the total radiosonde sites have PBLH values ranging from 1.6 to 2.0 km. Overall, CALIOP-derived PBLHs are well consistent with radiosonde-derived PBLHs. To our knowledge, this study is the first intercomparison of PBLH on a large scale using the radiosonde network of China, shedding important light on the data quality of initial CALIOP-derived PBLH results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.A33A0812W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.A33A0812W"><span id="translatedtitle">Determination of the Mixing <span class="hlt">Layer</span> <span class="hlt">Height</span> Over two Sites, Using Pilot Balloons During the MILAGRO Campaign</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wohrnschimmel, H.; Alonso, A. L.; Ángeles, F.; Sosa, G.; Varela, J.; Cárdenas, B.</p> <p>2007-12-01</p> <p>Among the mechanisms that affect air quality there is a variety of meteorological processes. An important process in this context are the changes in the mixing <span class="hlt">layer</span> <span class="hlt">height</span> during a day and over the year. The mixing <span class="hlt">layer</span> <span class="hlt">height</span> is the portion of the atmosphere close to the surface <span class="hlt">layer</span> where air pollutants get diluted, without leaving this <span class="hlt">layer</span>. Therefore, it is important to describe the variations in the <span class="hlt">height</span> of the mixing <span class="hlt">layer</span>, i.e. the vertical dilution of air pollution, since this is a process mitigating naturally the impact of emissions. There exist different methods to obtain information on the mixing <span class="hlt">layer</span> <span class="hlt">height</span>, among them radio soundings, the application of vertical wind profilers, and launching pilot balloons. In this study, pilot balloons have been used simultaneously over two sites of the Mexico City Metropolitan Area during the MILAGRO campaign in March 2006. The objective was to determine the vertical wind profiles and derive information on the mixing <span class="hlt">layer</span> <span class="hlt">height</span>. Daily, four pilot balloons were launched, at 9:00, 12:00, 15:00, and 18:00 hours, over Tenango del Aire (a rural area in the Southeast of Mexico City), and over Ciudad Universitaria, in the Southern metropolitan area. At some occasions, night time measurements have been carried out at 21:00 and 24:00. A variability of the diurnal evolution of the mixing <span class="hlt">layer</span> was observed along March, which could be related to surface temperature. The diurnal evolution showed a sudden growth of the mixing <span class="hlt">layer</span> between 9:00 and 12:00 hours. Data intercomparisons were carried out for pilot balloons versus radio soundings during a few days at a third site, Tula, in the North of Mexico City. Both intercomparisons showed that pilot balloons are an effective method to obtain information about the development of the mixing <span class="hlt">layer</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013KPCB...29..243M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013KPCB...29..243M&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Aerosol</span> in the upper <span class="hlt">layer</span> of earth's atmosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morozhenko, A. V.; Vidmachenko, A. P.; Nevodovskii, P. V.</p> <p>2013-09-01</p> <p><span class="hlt">Aerosol</span> <span class="hlt">layers</span> exist in the upper atmospheres of Venus, Mars, Jupiter, Saturn and the Earth. The reason for their existence may be meteorites, rings, and removal of particles of planetary origin. Observations from 1979 to 1992 showed that the optical thickness of <span class="hlt">aerosol</span> over the Earth's polar regions changed from tau =0.0002 up to tau =.1 for lambda = 1000 nm. The greatest values of tau were in 1984 and 1992 and they were preceded by a strong volcanic activity of El Chichon (1982) and Pinatubo (1991). We show that the above-mentioned increase in the optical thickness of the stratosphere <span class="hlt">aerosol</span> can lead to the ozone <span class="hlt">layer</span> decrease detected in 1970. The stratospheric <span class="hlt">aerosol</span> nature (real part of refractive index), effective particle size r and changing tau with latitude remain un solved. Among distance methods for the determination of nr and r efficient is the analysis of the phase dependence of the polarization degree. The observational values of the intensity and pol arization degree invisible light are due to optical properties of the surface and optical thickness of the atmosphere, the values of which vary with latitude, longitude and time. Therefore, it is impossible to identify accurately the stratospheric <span class="hlt">aerosol</span> contribution. When observing in UV at lambda < 300 nm, the ozone <span class="hlt">layer</span> cuts off the influence of the surface and the Earth's atmosphere to an altitude from 20 to 25 km. In this spectral region some negative factors can take place, namely, the emission of various gases playing depolarizing role, horizontal inhomogeneity of the effective optical thickness of ozone <span class="hlt">layer</span>, and oriented particles (the polarization plane variation points to their presence).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26490909','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26490909"><span id="translatedtitle">Modeling the feedback between <span class="hlt">aerosol</span> and boundary <span class="hlt">layer</span> processes: a case study in Beijing, China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Miao, Yucong; Liu, Shuhua; Zheng, Yijia; Wang, Shu</p> <p>2016-02-01</p> <p>Rapid development has led to frequent haze in Beijing. With mountains and sea surrounding Beijing, the pollution is found to be influenced by the mountain-plain breeze and sea-land breeze in complex ways. Meanwhile, the presence of <span class="hlt">aerosols</span> may affect the surface energy balance and impact these boundary <span class="hlt">layer</span> (BL) processes. The effects of BL processes on <span class="hlt">aerosol</span> pollution and the feedback between <span class="hlt">aerosol</span> and BL processes are not yet clearly understood. Thus, the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) is used to investigate the possible effects and feedbacks during a haze episode on 23 September 2011. Influenced by the onshore prevailing wind, sea-breeze, and upslope breeze, about 45% of surface particulate matter (PM)2.5 in Beijing are found to be contributed by its neighbor cities through regional transport. In the afternoon, the development of upslope breeze suppresses the growth of BL in Beijing by imposing a relatively low thermal stable <span class="hlt">layer</span> above the BL, which exacerbates the pollution. Two kinds of feedback during the daytime are revealed as follows: (1) as the <span class="hlt">aerosols</span> absorb and scatter the solar radiation, the surface net radiation and sensible heat flux are decreased, while BL temperature is increased, resulting in a more stable and shallower BL, which leads to a higher surface PM2.5 concentration in the morning and (2) in the afternoon, as the presence of <span class="hlt">aerosols</span> increases the BL temperature over plains, the upslope breeze is weakened, and the boundary <span class="hlt">layer</span> <span class="hlt">height</span> (BLH) over Beijing is heightened, resulting in the decrease of the surface PM2.5 concentration there. PMID:26490909</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A13K3321X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A13K3321X"><span id="translatedtitle">What is the Planetary Boundary <span class="hlt">Layer</span> <span class="hlt">Height</span> in a Global Perspective?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, F.; Syndergaard, S.; von Engeln, A.</p> <p>2014-12-01</p> <p>The planetary boundary <span class="hlt">layer</span> (PBL) <span class="hlt">height</span> is a fundamental parameter characterizing the vertical extent of atmospheric mixing near the surface. It is critical for understanding the PBL process and low cloud evolution and its feedback on the climate system, which remains a key uncertainty in climate modeling. The PBL <span class="hlt">height</span> is generally defined as the altitude of a transition <span class="hlt">layer</span> where air temperature or humidity gradient are significant within the lowest 1-5 kilometers above the surface. Numerous thermodynamic parameters, including temperature, humidity (specific/relative humidity) and their derivatives (e.g., potential/virtual potential temperature etc.) have been widely used to define the PBL <span class="hlt">height</span>. Advances in satellite remote sensing technique allow novel ways to detect the PBL <span class="hlt">heights</span> from space. Many new parameters are proposed for PBL <span class="hlt">height</span> detection including GPS radio occultation (RO) measurements (e.g., refractivity, bending angle and dry-temperature) and CALIPSO lidar backscattering measurements (e.g., cloud-top-<span class="hlt">height</span>). Large discrepancy among various PBL <span class="hlt">height</span> definitions was revealed from radiosonde analyses, which however are restricted over lands and represent limited horizontal scales of atmospheric conditions. In this talk, we investigate the definition difference in a global perspective by using multi-year high-resolution ERA-interim (1 degree grid with 60 vertical <span class="hlt">layers</span>) global analysis. Automatic algorithms are applied to compute the PBL <span class="hlt">heights</span> with various physical parameters (both conventional and GPS RO) at each model grid. The global PBL <span class="hlt">height</span> seasonal climatology and the difference among the climatologies are derived. Large discrepancy between the thermal-based and humidity-based PBL <span class="hlt">height</span> definitions is most prominent over tropical and polar regions. Humidity-based PBL <span class="hlt">heights</span> become problematic over dry regions, especially over high-latitude in winter season. The cloud-top <span class="hlt">height</span> from CALIPSO is consistent with most physical</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7678E..0BK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7678E..0BK"><span id="translatedtitle">Forecasting of <span class="hlt">aerosol</span> extinction of the sea and coastal atmosphere surface <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaloshin, G. A.</p> <p>2010-04-01</p> <p>The focus of our study is the extinction and optical effects due to <span class="hlt">aerosol</span> in a specific coastal region. The <span class="hlt">aerosol</span> microphysical model of the marine and coastal atmosphere surface <span class="hlt">layer</span> is considered. The model is made on the basis of the long-term experimental data received at researches of <span class="hlt">aerosol</span> sizes distribution function (dN/dr) in the band particles sizes in 0.01 - 100 μk. The model is developed by present time for the band of <span class="hlt">heights</span> is 0 - 25 m. Bands of wind speed is 3 - 18 km/s, sizes fetch is up to 120 km, RH = 40 - 98 %. Key feature of model is parameterization of amplitude and width of the modes as functions of fetch and wind speed. In the paper the dN/dr behavior depending at change meteorological parameters, <span class="hlt">heights</span> above sea level, fetch (X), wind speed (U) and RH is show. On the basis of the developed model with usage of Mie theory for spheres the description of last version of developed code MaexPro (Marine <span class="hlt">Aerosol</span> Extinction Profiles) for spectral profiles of <span class="hlt">aerosol</span> extinction coefficients α(λ) calculations in the wavelength band, equal λ = 0.2 - 12 μm is presented. The received results are compared models NAN and ANAM. Also α(λ) profiles for various wind modes (combinations X and U) calculated by MaexPro code are given. The calculated spectrums of α(λ) profiles are compared with experimental data of α(λ) received by a transmission method in various geographical areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7318H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7318H"><span id="translatedtitle">Does the vertical profile of ethane contain more insight into mixing <span class="hlt">layer</span> <span class="hlt">height</span> than carbon monoxide?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herndon, Scott; Yacovitch, Tara; Pusede, Sally; Diskin, Glenn; DiGangi, Joshua; Sachse, Glenn; Crawford, James</p> <p>2015-04-01</p> <p>To improve the interpretation of satellite data measurements near the surface, the DISCOVER-AQ project embarked on a four year campaign to produce an integrated dataset of airborne and surface based measurements at various locations in North America. One of the key metrics when pursuing the the goal of measuring the surface air quality from space is the mixing <span class="hlt">layer</span> <span class="hlt">height</span>. The measurement phase in 2014 included the novel 1-Hz Aerodyne Research, Inc. fast Ethane Spectrometer to distinguish the methane emissions from thermogenic (oil&gas) and biogenic sources in the Denver-Julesberg basin. A second potential use of ethane as a determinant of mixing <span class="hlt">layer</span> <span class="hlt">height</span> is revealed in the analysis of 213 vertical profiles collected at 7 points during 21 flights. The findings are evaluated relative to other in-situ metrics, such as carbon monoxide and remote sensing attributions of mixing <span class="hlt">layer</span> <span class="hlt">height</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..DFD.L1005S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..DFD.L1005S"><span id="translatedtitle">Delay in convection in nocturnal boundary <span class="hlt">layer</span> due to <span class="hlt">aerosol</span>-induced cooling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, Dhiraj Kumar; Ponnulakshmi, V. K.; Subramanian, G.; Sreenivas, K. R.</p> <p>2012-11-01</p> <p>Heat transfer processes in the nocturnal boundary <span class="hlt">layer</span> (NBL) influence the surface energy budget, and play an important role in many micro-meteorological processes including the formation of inversion <span class="hlt">layers</span>, radiation fog, and in the control of air-quality near the ground. Under calm clear-sky conditions, radiation dominates over other transport processes, and as a result, the air <span class="hlt">layers</span> just above ground cool the fastest after sunset. This leads to an anomalous post-sunset temperature profile characterized by a minimum a few decimeters above ground (Lifted temperature minimum). We have designed a laboratory experimental setup to simulate LTM, involving an enclosed <span class="hlt">layer</span> of ambient air, and wherein the boundary condition for radiation is decoupled from those for conduction and convection. The results from experiments involving both ambient and filtered air indicate that the high cooling rates observed are due to the presence of <span class="hlt">aerosols</span>. Calculated Rayleigh number of LTM-type profiles is of the order 105-107 in the field and of order 103-105 in the laboratory. In the LTM region, there is convective motion when the Rayleigh number is greater than 104 rather than the critical Rayleigh number (Rac = 1709). The diameter of convection rolls is a function of <span class="hlt">height</span> of minimum of LTM-type profiles. The results obtained should help in the parameterization of transport process in the nocturnal boundary <span class="hlt">layer</span>, and highlight the need to accounting the effects of <span class="hlt">aerosols</span> and ground emissivity in climate models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ACP....14.4263K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ACP....14.4263K"><span id="translatedtitle">Atmospheric boundary <span class="hlt">layer</span> top <span class="hlt">height</span> in South Africa: measurements with lidar and radiosonde compared to three atmospheric models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Korhonen, K.; Giannakaki, E.; Mielonen, T.; Pfüller, A.; Laakso, L.; Vakkari, V.; Baars, H.; Engelmann, R.; Beukes, J. P.; Van Zyl, P. G.; Ramandh, A.; Ntsangwane, L.; Josipovic, M.; Tiitta, P.; Fourie, G.; Ngwana, I.; Chiloane, K.; Komppula, M.</p> <p>2014-04-01</p> <p>Atmospheric lidar measurements were carried out at Elandsfontein measurement station, on the eastern Highveld approximately 150 km east of Johannesburg in South Africa throughout 2010. The <span class="hlt">height</span> of the planetary boundary <span class="hlt">layer</span> (PBL) top was continuously measured using a Raman lidar, PollyXT (POrtabLe Lidar sYstem eXTended). High atmospheric variability together with a large surface temperature range and significant seasonal changes in precipitation were observed, which had an impact on the vertical mixing of particulate matter, and hence, on the PBL evolution. The results were compared to radiosondes, CALIOP (Cloud-<span class="hlt">Aerosol</span> Lidar with Orthogonal Polarization) space-borne lidar measurements and three atmospheric models that followed different approaches to determine the PBL top <span class="hlt">height</span>. These models included two weather forecast models operated by ECMWF (European Centre for Medium-range Weather Forecasts) and SAWS (South African Weather Service), and one mesoscale prognostic meteorological and air pollution regulatory model TAPM (The Air Pollution Model). The ground-based lidar used in this study was operational for 4935 h during 2010 (49% of the time). The PBL top <span class="hlt">height</span> was detected 86% of the total measurement time (42% of the total time). Large seasonal and diurnal variations were observed between the different methods utilised. High variation was found when lidar measurements were compared to radiosonde measurements. This could be partially due to the distance between the lidar measurements and the radiosondes, which were 120 km apart. Comparison of lidar measurements to the models indicated that the ECMWF model agreed the best with mean relative difference of 15.4%, while the second best correlation was with the SAWS model with corresponding difference of 20.1%. TAPM was found to have a tendency to underestimate the PBL top <span class="hlt">height</span>. The wind speeds in the SAWS and TAPM models were strongly underestimated which probably led to underestimation of the vertical wind</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992RaSc...27..635M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992RaSc...27..635M"><span id="translatedtitle">A simple method to determine evaporation duct <span class="hlt">height</span> in the sea surface boundary <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Musson-Genon, Luc; Gauthier, Sylvie; Bruth, Eric</p> <p>1992-09-01</p> <p>A formulation to determine the evaporation duct <span class="hlt">height</span> in the sea surface boundary <span class="hlt">layer</span> is presented. This formulation is based upon the theory of similarity of Monin Obukhov by using analytical solutions currently used in the field of numerical weather prediction. The proposed solution is simple, coherent with the surface boundary <span class="hlt">layer</span> parameterization used in the Meteo France and European Centre for Medium-Range Weather Forecasts weather prediction models and gives good results when compared to more traditional methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150000727','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150000727"><span id="translatedtitle">Estimating Planetary Boundary <span class="hlt">Layer</span> <span class="hlt">Heights</span> from NOAA Profiler Network Wind Profiler Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Molod, Andrea M.; Salmun, H.; Dempsey, M</p> <p>2015-01-01</p> <p>An algorithm was developed to estimate planetary boundary <span class="hlt">layer</span> (PBL) <span class="hlt">heights</span> from hourly archived wind profiler data from the NOAA Profiler Network (NPN) sites located throughout the central United States. Unlike previous studies, the present algorithm has been applied to a long record of publicly available wind profiler signal backscatter data. Under clear conditions, summertime averaged hourly time series of PBL <span class="hlt">heights</span> compare well with Richardson-number based estimates at the few NPN stations with hourly temperature measurements. Comparisons with clear sky reanalysis based estimates show that the wind profiler PBL <span class="hlt">heights</span> are lower by approximately 250-500 m. The geographical distribution of daily maximum PBL <span class="hlt">heights</span> corresponds well with the expected distribution based on patterns of surface temperature and soil moisture. Wind profiler PBL <span class="hlt">heights</span> were also estimated under mostly cloudy conditions, and are generally higher than both the Richardson number based and reanalysis PBL <span class="hlt">heights</span>, resulting in a smaller clear-cloudy condition difference. The algorithm presented here was shown to provide a reliable summertime climatology of daytime hourly PBL <span class="hlt">heights</span> throughout the central United States.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.A43A0225B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.A43A0225B&link_type=ABSTRACT"><span id="translatedtitle">Inter-comparison of lidar methods for obtaining planetary boundary-<span class="hlt">layer</span> <span class="hlt">height</span> from a July 2012 monitoring campaign over the Iberian Peninsula in the framework of EARLINET</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Banks, R. F.; Baldasano, J. M.; Comerón, A.; Sicard, M.</p> <p>2013-12-01</p> <p>The depth of the planetary boundary-<span class="hlt">layer</span> (PBL) is defined as the <span class="hlt">height</span> of the inversion level separating the free troposphere (FT) from the boundary-<span class="hlt">layer</span> (Stull, 1988). Reliable representation of PBL <span class="hlt">height</span> is important in applications ranging from climate studies to air quality modeling. Convective turbulent mixing processes are dominant in the mixing <span class="hlt">layer</span> of the PBL and have a major influence on the growth and transport of atmospheric pollutants. In recent years, lidar (laser radar) has proven to be a useful operational tool for nearly continuous monitoring of the lowest levels of the atmosphere with high spatial (~ 3.75 m) and temporal (< 5 min) resolutions. Four Raman-elastic multi-wavelength lidar stations from EARLINET (European <span class="hlt">Aerosol</span> Research Lidar Network) conducted a 72-hr campaign of continuous observations over Spain (Barcelona, Granada, Madrid) and Portugal (Evora) in early July 2012. This study systematically exploits 1-min averaged, range-squared-corrected lidar signals (RSCS) from the 532 nm analog reception channel of the instruments. Several methods that have been applied in previous literature to derive PBL <span class="hlt">height</span> from vertical <span class="hlt">aerosol</span> backscatter profiles are compared. Most widely used are derivative techniques such as the gradient method (GM), inflection point method (IPM), and logarithm gradient method (LGM) and covariance techniques such as the wavelet covariance transform (WCT) method using a Haar wavelet. The methods function by detecting steep gradients in the <span class="hlt">aerosol</span> backscatter profile, a proxy for the transition zone between the PBL and FT. It is found that all the methods provide comparable results. However, it is determined that WCT is an optimal method as it is more computationally efficient than the derivative techniques. In summer, PBL <span class="hlt">heights</span> over the Iberian Peninsula are typically between 1-3 km. In addition, spatial patterns and diurnal variation of the PBL <span class="hlt">height</span> and an analysis of the meteorological situation over the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRD..11716117A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRD..11716117A"><span id="translatedtitle">Planetary boundary <span class="hlt">layer</span> <span class="hlt">heights</span> from GPS radio occultation refractivity and humidity profiles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ao, Chi O.; Waliser, Duane E.; Chan, Steven K.; Li, Jui-Lin; Tian, Baijun; Xie, Feiqin; Mannucci, Anthony J.</p> <p>2012-08-01</p> <p>The <span class="hlt">height</span> of the planetary boundary <span class="hlt">layer</span> (PBL) is an important parameter that relates to the various processes associated with the PBL. In this paper, we use Global Positioning System radio occultation (GPSRO) measurements to derive a global climatology of PBL <span class="hlt">heights</span>. Utilizing the strength of GPSRO in capturing fine vertical structures, the top of the PBL is defined to be the <span class="hlt">height</span> at which the vertical gradient of the refractivity or water vapor partial pressure is minimum, corresponding to the <span class="hlt">height</span> where the refractivity or water vapor pressure changes most rapidly. A "sharpness parameter" is defined that quantifies the applicability of these definitions. The sharpness parameter is largest over the subtropical regions characterized by strong subsidence. When the sharpness parameter is large, the refractivity- and moisture-based <span class="hlt">heights</span> are shown to converge. We derived global PBL <span class="hlt">height</span> climatology using three years (Dec. 2006-Nov. 2009) of COSMIC/FORMOSAT-3 measurements and compared with values calculated from ECMWF Reanalysis Interim (ERA-Int). We found that the mean PBL <span class="hlt">heights</span> from GPSRO shared similar spatial and seasonal variations with ERA-Int; however, GPSRO <span class="hlt">heights</span> were higher by 500 m. The standard deviation was also higher from GPSRO, especially in the tropics. We present detailed comparisons between GPSRO and ERA-Int over the Pacific Ocean and the Sahara desert and examine the PBL <span class="hlt">height</span> distributions as well as its annual and diurnal variabilities. These results suggest that the underlying causes of the bias between GPSRO and ERA-Int likely vary from region to region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811061S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811061S"><span id="translatedtitle">GPS RO sensing of Boundary <span class="hlt">Layer</span> <span class="hlt">Height</span> within Southern Ocean Cyclones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schuddeboom, Alex; McDonald, Adrian; Katurji, Marwan; Morgenstern, Olaf; Harvey, Mike</p> <p>2016-04-01</p> <p>The COSMIC constellation of GPS RO satellites has been used extensively over the previous few years to generate climatologies of boundary <span class="hlt">layer</span> <span class="hlt">height</span> (BLH). These satellites use high precision clocks to measure the time it takes for a signal to be transmitted through the atmosphere. From the time measurements, the angle of refraction of the signal can be calculated and then used in turn to calculate atmospheric refractivity. Boundary <span class="hlt">layer</span> <span class="hlt">heights</span> can then be determined by identifying sharp gradients in the refractivity profile. The results of this approach have been compared with radiosonde data and show a high level of agreement. By using this technique, we also generated a BLH climatology which was then used to analyse how the <span class="hlt">height</span> of the boundary <span class="hlt">layer</span> varies within the specific meteorological context of Southern Ocean cyclones. Analysis of the BLH behaviour over cyclones was primarily based upon generating cyclone composites. This is done by averaging together measurements in a cyclone relative framework to generate a representative cyclone. This technique allows a direct examination of the mean state, however it is also valuable for further analysis such as splitting the composite into regions and analysing the distribution of values over each of these sub-regions. We also investigated the relationship between boundary <span class="hlt">layer</span> <span class="hlt">height</span> and surface variables. There is a particularly strong negative relationship between sea ice concentration and boundary <span class="hlt">layer</span> <span class="hlt">height</span>. The reasons for this phenomenon are not entirely clear but appear to be at least partially related to changes in the surface sensible heat flux. The effects of other surface variables such as air temperature, sea surface temperature and wind speeds were relatively minor.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1225173','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1225173"><span id="translatedtitle">Estimation of the mixing <span class="hlt">layer</span> <span class="hlt">height</span> over a high altitude site in Central Himalayan region by using Doppler lidar</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shukla, K. K.; Phanikumar, D. V.; Newsom, Rob K.; Kumar, Niranjan; Ratnam, Venkat; Naja, M.; Singh, Narendra</p> <p>2014-03-01</p> <p>A Doppler lidar was installed at Manora Peak, Nainital (29.4 N; 79.2 E, 1958 amsl) to estimate mixing <span class="hlt">layer</span> <span class="hlt">height</span> for the first time by using vertical velocity variance as basic measurement parameter for the period September-November 2011. Mixing <span class="hlt">layer</span> <span class="hlt">height</span> is found to be located ~0.57 +/- 0.1and 0.45 +/- 0.05km AGL during day and nighttime, respectively. The estimation of mixing <span class="hlt">layer</span> <span class="hlt">height</span> shows good correlation (R>0.8) between different instruments and with different methods. Our results show that wavelet co-variance transform is a robust method for mixing <span class="hlt">layer</span> <span class="hlt">height</span> estimation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22395727','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22395727"><span id="translatedtitle">Determination of the Schottky barrier <span class="hlt">height</span> of ferromagnetic contacts to few-<span class="hlt">layer</span> phosphorene</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Anugrah, Yoska; Robbins, Matthew C.; Koester, Steven J.; Crowell, Paul A.</p> <p>2015-03-09</p> <p>Phosphorene, the 2D analogue of black phosphorus, is a promising material for studying spin transport due to its low spin-orbit coupling and its ½ nuclear spin, which could allow the study of hyperfine effects. In this work, the properties of permalloy (Py) and cobalt (Co) contacts to few-<span class="hlt">layer</span> phosphorene are presented. The Schottky barrier <span class="hlt">height</span> was extracted and determined as a function of gate bias. Flat-band barrier <span class="hlt">heights</span>, relative to the valence band edge, of 110 meV and 200 meV were determined for Py and Co, respectively. These results are important for future studies of spin transport in phosphorene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9645E..0FD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9645E..0FD"><span id="translatedtitle">Detecting the planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> from low-level jet with Doppler lidar measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de A. Moreira, G.; Marques, M. T. A.; Nakaema, W.; Moreira, A. C. de C. A.; Landulfo, E.</p> <p>2015-10-01</p> <p>The planetary boundary <span class="hlt">layer</span> (PBL) is an important region of study in the troposphere and one of its more important variable: the PBL <span class="hlt">height</span> (PBLH) is not easy to detect, mainly in stable conditions due to its complexity. In order to detect the PBLH in stable conditions, in this paper, we apply the low-lev jet (LLJ) method using Doppler lidar measurements, which consists on detecting the LLJ and its maximum velocity <span class="hlt">height</span>, corresponding to the PBLH. In addition, we analyze this method by comparing and relating it with the variance and bulk Richardson number (BRN) method, ensuring its efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19980227631&hterms=marine+structure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmarine%2Bstructure','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19980227631&hterms=marine+structure&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmarine%2Bstructure"><span id="translatedtitle">The detection of clouds, <span class="hlt">aerosols</span> and marine atmospheric boundary <span class="hlt">layer</span> characteristics from simulated GLAS data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Palm, Stephen P.; Spinhirne, James D.</p> <p>1998-01-01</p> <p>Scheduled for launch in 2001 as part of NASA's Earth Observing System (EOS), the Geoscience Laser Altimeter System (GLAS) will provide continuous laser sounding of the earth's atmosphere from space for the first time. From its polar orbit about 600 km above the surface, GLAS will employ a 40 Hz solid state laser operating at 1064 nm to measure topography to an accuracy of 10 cm. Simultaneously, the atmospheric channels (1064 and 532 nm) of GLAS will provide profiles of atmospheric backscatter from 40 km to the ground with 75 meter vertical resolution (Spinhirne and Palm, 1996). These measurements will give scientists an unprecedented global data set on the vertical structure of clouds and <span class="hlt">aerosols</span> which will greatly aid research efforts aimed at understanding their effects on climate and their role in climate change (Hartman, 1994). To better understand and predict the performance of the GLAS atmospheric channels, a computer model was developed to simulate the type of signal that the instrument would likely produce. The model uses aircraft lidar data and provides realistic simulated GLAS data sets over large areas spanning a wide range of atmospheric conditions. These simulated GLAS datasets are invaluable for designing and testing algorithms for the retrieval of parameters such as cloud and <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span>, optical depth and extinction cross section. This work is currently proceeding and in this paper we will present results of the cloud and <span class="hlt">aerosol</span> detection algorithm with emphasis on the detection of Marine Atmospheric Boundary <span class="hlt">Layer</span> (MABL) <span class="hlt">aerosol</span>. In addition, we use a recently developed technique to ascertain the feasability of estimating MABL moisture and temperature structure from spaceborne systems such as GLAS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.9516V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.9516V"><span id="translatedtitle">The Importance of the Vertical Location of <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> on Convective Storms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van den Heever, Susan; Grant, Leah</p> <p>2014-05-01</p> <p>Enhanced <span class="hlt">aerosol</span> concentrations appear to influence a number of the aspects of convective storms including the strength of the convective updraft, the intensity of the cold pool, and the microphysical and radiative characteristics of the convective anvil. However, in order for such influences to occur, <span class="hlt">aerosols</span> need to be effectively ingested by the storm system of interest. The vertical location of an <span class="hlt">aerosol</span> <span class="hlt">layer</span> impacting a convective storm may influence how effectively <span class="hlt">aerosol</span> are ingested by the storm system, and hence the degree to which the ingested <span class="hlt">aerosol</span> subsequently influence storm microphysical and radiative processes. Furthermore, if the <span class="hlt">aerosol</span> species impacting the storm are effective at absorbing solar radiation, heating within the <span class="hlt">aerosol</span> <span class="hlt">layer</span> enhances atmospheric stability, the level of which will be dictated by where the <span class="hlt">aerosol</span> <span class="hlt">layer</span> is located. Enhanced static stability may have negative impacts on the initial development of the convection of interest. Convective storms developing within environments of the same <span class="hlt">aerosol</span> optical depth may therefore respond differently to <span class="hlt">aerosol</span> indirect forcing by virtue of where the <span class="hlt">aerosol</span> <span class="hlt">layer</span> is vertically located. In this talk, the results of various high-resolution, cloud-resolving simulations will be presented, in which the sensitivity to the vertical location of the <span class="hlt">aerosol</span> source on the convective development, <span class="hlt">aerosol</span> ingestion efficiency, and subsequent microphysical and radiative properties are investigated. Microphysical budgets and storm trajectories will form an integral part of the analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JASTP..70.1904S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JASTP..70.1904S"><span id="translatedtitle"><span class="hlt">Height</span> and critical frequency variations of the sporadic-E <span class="hlt">layer</span> at midlatitudes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Šauli, P.; Bourdillon, A.</p> <p>2008-12-01</p> <p>The present study concerns variations in <span class="hlt">height</span> and critical frequency of sporadic E <span class="hlt">layer</span> over a wide period range of hours to several days, covering tidal and planetary oscillation domain. Besides periodicities in the tidal and planetary range that are known to occur within time series of critical frequencies (foEs) of sporadic-E <span class="hlt">layer</span> [Pancheva, D., Haldoupis, C., Meek, C.E., Manson, A.H., Mitchell, N.J., 2003. Evidence of a role for modulated atmospheric tides in the dependence of sporadic E <span class="hlt">layers</span> on planetary waves. Journal of Geophysical Research 108, Art. No. 1176; Haldoupis, C., Pancheva, D., Michell, N.J., 2004. A study of tidal and planetary wave periodicities present in midlatitude sporadic E <span class="hlt">layers</span>. Journal of Geophysical Research 109, Art. No. A02302] among others, we evidence the existence of the 4-day planetary wave well developed in the <span class="hlt">height</span> of sporadic E time serie (hEs). Moreover it is shown that the central-period of the diurnal tidal component of hEs is not exactly 24 h but it varies between 22 and 26 h at the planetary wave period. At a first glance, this is surprising since the origin of the diurnal tide is a forced oscillation with a 24 h period due to the Earth rotation and the periodic heating of the atmosphere by the Sun. Our interpretation is based on the perturbation of the <span class="hlt">height</span> of the Es <span class="hlt">layer</span> imposed by the planetary wave. In this mechanism the Es <span class="hlt">layer</span> is moved up and down by the planetary wave producing a Doppler effect and resulting in a shift of the central-period around 24 h. With this interpretation, the excursion of the central-period is related to the vertical velocity perturbation of the Es <span class="hlt">layer</span> due to the planetary wave. For a central period varying between 22 and 26 h the peturbation velocities are 0.026 and , respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A24B..04B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A24B..04B"><span id="translatedtitle">Relating <span class="hlt">Aerosol</span> Mass and Optical Depth in the Summertime Continental Boundary <span class="hlt">Layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brock, C. A.; Wagner, N.; Middlebrook, A. M.; Attwood, A. R.; Washenfelder, R. A.; Brown, S. S.; McComiskey, A. C.; Gordon, T. D.; Welti, A.; Carlton, A. G.; Murphy, D. M.</p> <p>2014-12-01</p> <p><span class="hlt">Aerosol</span> optical depth (AOD), the column-integrated ambient <span class="hlt">aerosol</span> light extinction, is determined from satellite and ground-based remote sensing measurements. AOD is the parameter most often used to validate earth system model simulations of <span class="hlt">aerosol</span> mass. Relating <span class="hlt">aerosol</span> mass to AOD, however, is problematic due to issues including <span class="hlt">aerosol</span> water uptake as a function of relative humidity (RH) and the complicated relationship between <span class="hlt">aerosol</span> physicochemical properties and light extinction. Measurements of <span class="hlt">aerosol</span> microphysical, chemical, and optical properties help to constrain the relationship between <span class="hlt">aerosol</span> mass and optical depth because <span class="hlt">aerosol</span> extinction at ambient RH is a function of the abundance, composition and size distribution of the <span class="hlt">aerosol</span>. We use vertical profiles of humidity and dry <span class="hlt">aerosol</span> extinction observed in the southeastern United States (U.S.) to examine the relationship between submicron <span class="hlt">aerosol</span> mass concentration and extinction at ambient RH. We show that the κ-Köhler parameterization directly, and without additional Mie calculations, describes the change in extinction with varying RH as a function of composition for both aged <span class="hlt">aerosols</span> typical of the polluted summertime continental boundary <span class="hlt">layer</span> and the biomass burning <span class="hlt">aerosols</span> we encountered. We calculate how AOD and the direct radiative effect in the eastern U.S. have likely changed due to trends in <span class="hlt">aerosol</span> composition in recent decades. We also examine the sensitivity of AOD to the RH profile and to <span class="hlt">aerosol</span> composition, size distribution and abundance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770051683&hterms=1893&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D1893','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770051683&hterms=1893&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D1893"><span id="translatedtitle">Contribution to polar albedo from a mesospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hummel, J. R.</p> <p>1977-01-01</p> <p>An examination is made of the impact of a <span class="hlt">layer</span> of particulate matter, assumed to be ice crystals, on the albedo of the polar region. The model is time dependent, includes the growth of the <span class="hlt">layer</span>, and incorporates the diffuse nature of radiation reflected from the surface and atmosphere. Although the magnitude of the effect is about an order of magnitude less than previous results, the impact is one of heating instead of cooling. It is also shown that ignoring the diffuse nature of the radiation reflected from the underlying earth-atmosphere system, as has been done in many previous simple models, can result in overestimation of the climatological impact of <span class="hlt">aerosols</span> in sign and magnitude by a factor of up to 4-6.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUSM.A33C..06T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUSM.A33C..06T"><span id="translatedtitle">Nocturnal Boundary <span class="hlt">Layer</span> Measurements during the Amazonian <span class="hlt">Aerosol</span> Characterization Experiment (AMAZE)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tota, J.; Fisch, G.; Santos, R.; Silva Dias, M.</p> <p>2009-05-01</p> <p>To characterize the Nocturnal Boundary <span class="hlt">Layer</span> (NBL) hourly profiles of wind, pressure, temperature, humidity and 5 sizes particles concentration, were made by using tethered balloon at INPA tropical Amazon rainforest Reserve (Cuieiras) 100 km northwest from Manaus city. The measurements were made during the wet season March/2008. The NBL <span class="hlt">height</span> was 100 to 150m, with a very well mixed <span class="hlt">layer</span> close to surface associate with temperature inversion. The wind profiles shows a very clear low level in two nights, about 500 to 900 m, and, in general, all nights show an stable and cooler air <span class="hlt">layer</span> close the surface uncoupled with outer residual boundary <span class="hlt">layer</span> above. At the site a very clear drainage flow from north quadrant down slope eastward quadrant during very the stable cases. This findings is correlates with particles profiles where was commonly trapped by stable <span class="hlt">layer</span> presenting high concentrations, for all 5 sizes measured, close to the surface at vegetation level and just above it. All nights presents high humidity with fog formation in three cases, associates with temperature below the 23C. The wind speed were very low about 0.5 to calm, in generally associate with drainage flow down hill. The NBL dynamics is a discussion issue associate to the <span class="hlt">aerosol</span> nocturnal mixing in complex terrain with tall vegetation, the currently AMAZE site case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.A11C0125T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.A11C0125T"><span id="translatedtitle">Nocturnal Boundary <span class="hlt">Layer</span> Measurements during the Amazonian <span class="hlt">Aerosol</span> Characterization Experiment (amaze)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tota, J.; Santos, R.; Fisch, G.; Querino, C.; Silva Dias, M.; Artaxo, P.; Guenther, A.; Martin, S.; Manzi, A.</p> <p>2008-12-01</p> <p>To characterize the Nocturnal Boundary <span class="hlt">Layer</span> (NBL) hourly profiles of wind, pressure, temperature, humidity and 5 sizes particles concentration, were made by using tethered balloon at INPA tropical Amazon rainforest Reserve (Cuieiras) 100 km northwest from Manaus city. The measurements were made during the wet season March/2008. The NBL <span class="hlt">height</span> was 100 to 150m, with a very well mixed <span class="hlt">layer</span> close to surface associate with temperature inversion. The wind profiles shows a very clear low level in two nights, about 500 to 900 m, and, in general, all nights show an stable and cooler air <span class="hlt">layer</span> close the surface uncoupled with outer residual boundary <span class="hlt">layer</span> above. At the site a very clear drainage flow from north quadrant down slope eastward quadrant during very the stable cases. This findings is correlates with particles profiles where was commonly trapped by stable <span class="hlt">layer</span> presenting high concentrations, for all 5 sizes measured, close to the surface at vegetation level and just above it. All nights presents high humidity with fog formation in three cases, associates with temperature below the 23°C. The wind speed were very low about 0.5 to calm, in generally associate with drainage flow down hill. The NBL dynamics is a discussion issue associate to the <span class="hlt">aerosol</span> nocturnal mixing in complex terrain with tall vegetation, the currently AMAZE site case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015FrEaS...3...77D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015FrEaS...3...77D&link_type=ABSTRACT"><span id="translatedtitle">Convective boundary <span class="hlt">layer</span> <span class="hlt">heights</span> over mountainous terrain – A review of concepts –</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Wekker, Stephan; Kossmann, Meinolf</p> <p>2015-12-01</p> <p>Mountainous terrain exerts an important influence on the Earth's atmosphere and affects atmospheric transport and mixing at a wide range of temporal and spatial scales. The vertical scale of this transport and mixing is determined by the <span class="hlt">height</span> of the atmospheric boundary <span class="hlt">layer</span>, which is therefore an important parameter in air pollution studies, weather forecasting, climate modeling, and many other applications. It is recognized that the spatio-temporal structure of the daytime convective boundary <span class="hlt">layer</span> (CBL) <span class="hlt">height</span> is strongly modified and more complex in hilly and mountainous terrain compared to flat terrain. While the CBL over flat terrain is mostly dominated by turbulent convection, advection from multi-scale thermally driven flows plays an important role for the CBL evolution over mountainous terrain. However, detailed observations of the CBL structure and understanding of the underlying processes are still limited. Characteristics of CBL <span class="hlt">heights</span> in mountainous terrain are reviewed for dry, convective conditions. CBLs in valleys and basins, where hazardous accumulation of pollutants is of particular concern, are relatively well-understood compared to CBLs over slopes, ridges, or mountain peaks. Interests in the initiation of shallow and deep convection, and of budgets and long-range transport of air pollutants and trace gases, have triggered some recent studies on terrain induced exchange processes between the CBL and the overlying atmosphere. These studies have helped to gain more insight into CBL structure over complex mountainous terrain, but also show that the universal definition of CBL <span class="hlt">height</span> over mountains remains an unresolved issue. The review summarizes the progress that has been made in documenting and understanding spatio-temporal behavior of CBL <span class="hlt">heights</span> in mountainous terrain and concludes with a discussion of open research questions and opportunities for future research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012cosp...39.2234Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39.2234Y"><span id="translatedtitle">Features of the amplitude-<span class="hlt">height</span>-frequency characteristics of midlatitude sporadic-E <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yusupov, Kamil; Akchurin, Adel</p> <p>2012-07-01</p> <p>At early investigation of an ionosphere the vertical pulse sounding was without separation magnetoionic components and such conditions allowed to observe interferential beatings or polarized fading over frequencies where traces of various magnetoionic component was crossing (overlapping). The beatings in F <span class="hlt">layer</span> traces are often observed and their origin easily are explain by an interference o - and x-mode whereas in sporadic-E <span class="hlt">layer</span> traces even observability of beatings of o- and x-modes is in doubt. Absence of experimental evidences of beatings is explain that measurements did not manage to be performed over the necessary time moment because of randomness and a rarity of occurrence high-intensity sporadic-E <span class="hlt">layers</span> (without properties of scattering on small scale irregularities) and because of high labour input at recording and processing of amplitude-frequency characteristics. The direct observation of interferential beatings became problematic when ionosondes with separations of magnetoionic components appeared. Moreover because of relative vicinity of gyro and background plasma frequencies and also the steep electron profile gradient the beatings in sporadic-E traces should occur between two o-modes because in typical diurnal low-intensity sporadic-E <span class="hlt">layers</span> (foEs<5MHz) x-mode will be strongly absorbed and the steep gradient on the bottom of sporadic-E <span class="hlt">layer</span> will strengthen magnetoionic coupling (between o- and x-modes) and lead occurrence of so-called z-mode. The z-mode (extraordinary mode with ordinary polarization) reflected in higher <span class="hlt">height</span> again takes the form of ordinary mode after passage of <span class="hlt">height</span> of reflection of ordinary mode and interferes with ordinary mode. However our observations show that beating in sporadic-E traces mostly occur because of interference about o- and x-modes. For detailed research of interference conditions the approximation of width of interference fringes (distance between consecutive minima in interference pattern) as a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1613694M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1613694M"><span id="translatedtitle">Observations of the atmospheric boundary <span class="hlt">layer</span> <span class="hlt">height</span> over Abu Dhabi, United Arab Emirates: Investigating boundary <span class="hlt">layer</span> climatology in arid regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marzooqi, Mohamed Al; Basha, Ghouse; Ouarda, Taha B. M. J.; Armstrong, Peter; Molini, Annalisa</p> <p>2014-05-01</p> <p>Strong sensible heat fluxes and deep turbulent mixing - together with marked dustiness and a low substrate water content - represent a characteristic signature in the boundary <span class="hlt">layer</span> over hot deserts, resulting in "thicker" mixing <span class="hlt">layers</span> and peculiar optical properties. Beside these main features however, desert ABLs present extremely complex local structures that have been scarcely addressed in the literature, and whose understanding is essential in modeling processes such as the transport of dust and pollutants, and turbulent fluxes of momentum, heat and water vapor in hyper-arid regions. In this study, we analyze a continuous record of observations of the atmospheric boundary <span class="hlt">layer</span> (ABL) <span class="hlt">height</span> from a single lens LiDAR ceilometer operated at Masdar Institute Field Station (24.4oN, 54.6o E, Abu Dhabi, United Arab Emirates), starting March 2013. We compare different methods for the estimation of the ABL <span class="hlt">height</span> from Ceilometer data such as, classic variance-, gradient-, log gradient- and second derivation-methods as well as recently developed techniques such as the Bayesian Method and Wavelet covariance transform. Our goal is to select the most suited technique for describing the climatology of the ABL in desert environments. Comparison of our results with radiosonde observations collected at the nearby airport of Abu Dhabi indicate that the WCT and the Bayesian method are the most suitable tools to accurately identify the ABL <span class="hlt">height</span> in all weather conditions. These two methods are used for the definition of diurnal and seasonal climatologies of the boundary <span class="hlt">layer</span> conditional to different atmospheric stability classes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EPJWC.11907006B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EPJWC.11907006B&link_type=ABSTRACT"><span id="translatedtitle">Validation of ASH Optical Depth and <span class="hlt">Layer</span> <span class="hlt">Height</span> from IASI using Earlinet Lidar Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balis, D.; Siomos, N.; Koukouli, M.; Clarisse, L.; Carboni, E.; Ventress, L.; Grainger, R.; Mona, L.; Pappalardo, G.</p> <p>2016-06-01</p> <p>The 2010 eruptions of the Icelandic volcano Eyjafjallajökull attracted the attention of the public and the scientific community to the vulnerability of the European airspace to volcanic eruptions. The European Space Agency project "Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards", called for the creation of an optimal End-to-End System for Volcanic Ash Plume Monitoring and Prediction. This system is based on improved and dedicated satellite-derived ash plume and sulphur dioxide level assessments, as well as an extensive validation, using among others ground-based measurements (Koukouli et al., 2014). The validation of volcanic ash levels and <span class="hlt">height</span> extracted from IASI/MetopA is presented in this work with emphasis on the ash plume <span class="hlt">height</span> and ash optical depth levels. European <span class="hlt">Aerosol</span> Research Lidar Network [EARLINET] lidar measurements are compared to different satellite estimates for two eruptive episodes. The validation results are extremely promising within the estimated uncertainties of each of the comparative datasets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A12E..06L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A12E..06L"><span id="translatedtitle">Marine Boundary <span class="hlt">Layer</span> <span class="hlt">Heights</span> over the Eastern North Pacific Based on Measurements from the MAGIC Field Campaign</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lewis, E. R.</p> <p>2014-12-01</p> <p>The MAGIC field campaign, funded and operated by the ARM (Atmospheric Radiation Measurement) Climate Research Facility of the US Department of Energy, occurred between September 2012 and October, 2013 aboard the Horizon Lines cargo container ship Spirit making regular trips between Los Angeles, CA and Honolulu, HI. Along this route, which lies very near the GPCI (GCSS Pacific Cross-section Intercomparison) transect, the predominant cloud regime changes from stratocumulus near the California coast to trade-wind cumulus near Hawaii. The transition between these two regimes is poorly understood and not accurately represented in models. The goal of MAGIC was to acquire statistic of this transition and thus improve its representation in models by making repeated transects through this region and measuring properties of clouds and precipitation, <span class="hlt">aerosols</span>, radiation, and atmospheric structure. To achieve these goals, the Second ARM Mobile Facility (AMF2) was deployed on the Horizon Spiritas it ran its regular route between Los Angeles and Honolulu. AMF2 consists of three 20-foot SeaTainers and includes three radars, lidars, a ceilometer, microwave radiometers, a total sky imager, disdrometers, and other instruments to measure properties of clouds and precipitation; and other instruments to measure properties of <span class="hlt">aerosols</span>, radiation, meteorological quantities, and sea surface temperature. Two technicians accompanied the AMF2, and scientists rode the ship as observers. Radiosondes were routinely launched four times daily, and during one round trip in July, 2013, eight radiosondes were launched each day. In total, more than 550 soundings were made. MAGIC made nearly 20 round trips between Los Angeles and Honolulu (and thus nearly 40 excursions through the stratocumulus-to-cumulus transition) and spent 200 days at sea, collecting an unprecedented data set. Boundary <span class="hlt">layer</span> <span class="hlt">heights</span> calculated from the radiosonde data using several different algorithms, and those from other</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9640E..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9640E..08S"><span id="translatedtitle">Performance test of the synergetic use of simulated lidar and microwave radiometer observations for mixing-<span class="hlt">layer</span> <span class="hlt">height</span> detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saeed, Umar; Rocadenbosch, Francesc; Crewell, Susanne</p> <p>2015-10-01</p> <p>There are several instruments and methods to retrieve the atmospheric Mixing <span class="hlt">Layer</span> <span class="hlt">Height</span> (MLH). However, none of these instruments or methods can measure the development of the MLH under all atmospheric conditions. For example, <span class="hlt">aerosol</span> signatures measured by backscatter lidars can be used to determine the MLH but this approach is reasonable only when the atmosphere is well-mixed. Microwave Radiometer (MWR) derived profiles have low vertical resolution and cannot resolve fine structures in the boundary <span class="hlt">layer</span>, especially, at higher altitudes. Here we propose a method which combines data from a ground-based lidar and a MWR, in simulated as well as real measurements scenarios, to overcome these limitations. The method works by fitting an erf-like transition model function to the section of range-corrected lidar backscatter signal. The section of the lidar backscatter signal for fitting the model function is obtained by incorporating the MWR estimates of MLH along with their uncertainties. The fitting is achieved by using an extended Kalman filter (EKF). The proposed approach, by exploiting the synergy between the two instruments, enables to detect MLH with original vertical and temporal resolutions. Test cases combining simulated data for a co-located lidar-ceilometer and a MWR are presented. The simulated data is obtained from the Dutch Atmospheric Large Eddy Simulation (DALES) model for boundary <span class="hlt">layer</span> studies. Doppler wind lidar along with radiosondes (whenever available) data is used to assess the quality of the synergetic MLH estimates. Data from the HD(CP)2 Observational Prototype Experiment (HOPE) campaign at Jülich, Germany is used to test the proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MNRAS.434.1205M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MNRAS.434.1205M"><span id="translatedtitle">Solar scintillation detection and ranging (SCIDAR) technique for measuring turbulent-<span class="hlt">layer</span> <span class="hlt">heights</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miura, Noriaki; Oh-ishi, Ayumu; Shionoya, Shingo; Watanabe, Koji; Kuwamura, Susumu; Baba, Naoshi; Ueno, Satoru; Ichimoto, Kiyoshi</p> <p>2013-09-01</p> <p>A solar SCIDAR (scintillation detection and ranging) technique is proposed for measuring the <span class="hlt">heights</span> of turbulent <span class="hlt">layers</span> using the Sun itself, instead of the binary stars used in night-time SCIDAR. A formula for the technique is derived under various assumptions: uniform intensity distributions on the solar surface and sparse speckle distributions on the image plane. It indicates that the cross-correlation of scintillation shadows yields peaks at positions corresponding to <span class="hlt">layer</span> <span class="hlt">heights</span>, although the shapes of peaks are blurred by both an extended seeing disc and a finite-sized field stop. A knife-edge effect caused by field stops in an observational system is also described, which yields another peak at the centre of the correlation plane. Observations were conducted using a solar SCIDAR system developed at the Hida Observatory in Japan. In many results, peaks on correlation planes demonstrated a contrast high enough for them to be distinguished from the background. Most of the distances to turbulent <span class="hlt">layers</span> derived from the scintillation peaks were found to be between 2.5 and 3.5 km. Use of a high-performance adaptive-optics system upstream of the SCIDAR system is suggested in order to provide better results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A24C..01B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A24C..01B"><span id="translatedtitle">Understanding the Processes Controlling <span class="hlt">Aerosol</span>-Cloud Interactions in the Arctic Marine Boundary <span class="hlt">Layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Browse, J.; Carslaw, K. S.; Pringle, K.; Mann, G.; Reddington, C.; Brooks, I. M.; Mulcahy, J.; Young, G.; Allan, J. D.; Liu, D.; Trembath, J.; Dean, A.; Yoshioka, M.</p> <p>2015-12-01</p> <p>Here we use multiple configurations of the UKCA chemistry and <span class="hlt">aerosol</span> scheme in a global climate model, capable of simulating cloud condensation nuclei (CCN) and cloud droplet number, to understand the processes controlling <span class="hlt">aerosol</span>-cloud interactions in the marine Arctic boundary <span class="hlt">layer</span>. Evaluation against an unprecedented number of <span class="hlt">aerosol</span> and cloud observations made available through the Global <span class="hlt">Aerosol</span> Synthesis and Science Project (GASSP), International Arctic Systems for Observing the Atmosphere (IASOA) and the 2013 ACCACIA campaign, suggest that Arctic summertime CCN is well represented in the model. Sensitivity studies indicate that DMS derived nucleation events are the primary source of Arctic summertime <span class="hlt">aerosol</span> increasing mean (median) surface CCN concentrations north of 70N from 21(14) cm-3 to 46(33) cm-3. However, evaluation against observed <span class="hlt">aerosol</span> size distributions suggests that UKCA overestimates nucleation mode (~10nm) particle concentrations either due to overestimation of boundary <span class="hlt">layer</span> nucleation rates or underestimation of the Arctic marine boundary <span class="hlt">layer</span> condensation sink.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.6802F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.6802F&link_type=ABSTRACT"><span id="translatedtitle">Analysis of modified MYJ and YSU boundary <span class="hlt">layer</span> schemes in WRF-Chem with respect to simulated boundary <span class="hlt">layer</span> <span class="hlt">heights</span> and pollutant concentrations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Forkel, Renate; Foreman, Richard; Emeis, Stefan</p> <p>2014-05-01</p> <p>To improve the performance of boundary <span class="hlt">layer</span> schemes currently applied within WRF-Chem (Grell et al., 2005), the Mellor-Yamada-Janjic (MYJ) model (Mellor and Yamada 1982) and the Yonsei University (YSU) PBL scheme (Hong et al. 2006) have been updated using data from a 100 m high offshore measurement tower called FINO1. The turbulence intensity in the Mellor-Yamada-Janjic model has been enhanced as described in Foreman and Emeis (2012). An alternative to the exchange coefficient for stable stratification in the YSU scheme is described in Foreman et al. (2014). These modifications to the two schemes have been applied and are compared with the existing schemes. For example, the updated MYJ scheme results in an improved representation of the turbulent kinetic energy throughout the boundary <span class="hlt">layer</span> as compared with the measurements at FINO1. The modified MYJ and YSU schemes, which have been originally developed for wind energy applications, have been implemented into version 3.5 of the WRF model. Simulations with WRF-Chem were carried out for Europe and the region of Augsburg in order to evaluate the effect of the modified PBL schemes on simulated PBL <span class="hlt">heights</span>, gas phase pollutant and <span class="hlt">aerosol</span> concentrations. Foreman, R.J. and S. Emeis, 2012. A method for increasing the turbulent kinetic energy in the Mellor-Yamada-Janjic boundary <span class="hlt">layer</span> parametrization. Boundary <span class="hlt">Layer</span> Meteorology 145:329-349. Foreman, R.J. S. Emeis and B. Canadillas, 2014. Stable boundary <span class="hlt">layer</span> parametrization without eddy viscosity or turbulent kinetic energy equation approaches. Submitted to Boundary <span class="hlt">Layer</span> Meteorology 2014. Grell, G. A., Peckham, S. E., Schmitz, R., McKeen, S. A., Frost, G., Skamarock,W. C., and Eder, B., 2005. Fully Coupled Online Chemistry within the WRF Model. Atmospheric Environment 39, 6957-6975. Hong S, Noh Y, Dudhia J 2006. Nonlocal boundary <span class="hlt">layer</span> vertical diffusion in a medium-range forecast model. Mon Wea Rev 124:2322-2339. Mellor GL, Yamada T 1982. Development of a turbulence</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016BoLMe.tmp...36M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016BoLMe.tmp...36M"><span id="translatedtitle">Parametrization of Planetary Boundary-<span class="hlt">Layer</span> <span class="hlt">Height</span> with Helicity and Verification with Tropical Cyclone Prediction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ma, Lei-Ming; Bao, Xu-Wei</p> <p>2016-04-01</p> <p>To reduce the discrepancy between simulated and observed tropical cyclones, we consider a new parametrization scheme for planetary boundary-<span class="hlt">layer</span> (PBL) <span class="hlt">height</span> based on helicity, intended to provide an improved description of the overall helical structures of the tropical cyclone PBL simulated in a numerical model. This scheme was preliminarily tested in the Yonsei University (YSU) PBL scheme integrated within the National Center for Atmospheric Research Weather Research and Forecasting model. Based on verification of track simulations for seven tropical cyclones that made landfall over China, tropical cyclone Morakot (2009) was selected for further evaluation of the new scheme. Compared with the original scheme based on the Richardson number (Ri), the new scheme elevated the PBL <span class="hlt">height</span> associated with intense convection, which is consistent with observation. Importantly, the new scheme improved the numerical simulation of intense rainfall by modulating the PBL environment for convection evolution. Furthermore, the PBL <span class="hlt">height</span> and 2-m temperature over land at night, which are frequently overestimated by the original YSU scheme, were improved using the new scheme. Because of its effects on PBL structures and convection evolution, the simulation of tropical cyclone Morakot intensity was improved by the new scheme.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22407921','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22407921"><span id="translatedtitle">Kinetic model for an auroral double <span class="hlt">layer</span> that spans many gravitational scale <span class="hlt">heights</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Robertson, Scott</p> <p>2014-12-15</p> <p>The electrostatic potential profile and the particle densities of a simplified auroral double <span class="hlt">layer</span> are found using a relaxation method to solve Poisson's equation in one dimension. The electron and ion distribution functions for the ionosphere and magnetosphere are specified at the boundaries, and the particle densities are found from a collisionless kinetic model. The ion distribution function includes the gravitational potential energy; hence, the unperturbed ionospheric plasma has a density gradient. The plasma potential at the upper boundary is given a large negative value to accelerate electrons downward. The solutions for a wide range of dimensionless parameters show that the double <span class="hlt">layer</span> forms just above a critical altitude that occurs approximately where the ionospheric density has fallen to the magnetospheric density. Below this altitude, the ionospheric ions are gravitationally confined and have the expected scale <span class="hlt">height</span> for quasineutral plasma in gravity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AMT.....9.1925Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AMT.....9.1925Y"><span id="translatedtitle">A new method for estimating <span class="hlt">aerosol</span> mass flux in the urban surface <span class="hlt">layer</span> using LAS technology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yuan, Renmin; Luo, Tao; Sun, Jianning; Liu, Hao; Fu, Yunfei; Wang, Zhien</p> <p>2016-04-01</p> <p>Atmospheric <span class="hlt">aerosol</span> greatly influences human health and the natural environment, as well as the weather and climate system. Therefore, atmospheric <span class="hlt">aerosol</span> has attracted significant attention from society. Despite consistent research efforts, there are still uncertainties in understanding its effects due to poor knowledge about <span class="hlt">aerosol</span> vertical transport caused by the limited measurement capabilities of <span class="hlt">aerosol</span> mass vertical transport flux. In this paper, a new method for measuring atmospheric <span class="hlt">aerosol</span> vertical transport flux is developed based on the similarity theory of surface <span class="hlt">layer</span>, the theory of light propagation in a turbulent atmosphere, and the observations and studies of the atmospheric equivalent refractive index (AERI). The results show that <span class="hlt">aerosol</span> mass flux can be linked to the real and imaginary parts of the atmospheric equivalent refractive index structure parameter (AERISP) and the ratio of <span class="hlt">aerosol</span> mass concentration to the imaginary part of the AERI. The real and imaginary parts of the AERISP can be measured based on the light-propagation theory. The ratio of the <span class="hlt">aerosol</span> mass concentration to the imaginary part of the AERI can be measured based on the measurements of <span class="hlt">aerosol</span> mass concentration and visibility. The observational results show that <span class="hlt">aerosol</span> vertical transport flux varies diurnally and is related to the <span class="hlt">aerosol</span> spatial distribution. The maximum <span class="hlt">aerosol</span> flux during the experimental period in Hefei City was 0.017 mg m-2 s-1, and the mean value was 0.004 mg m-2 s-1. The new method offers an effective way to study <span class="hlt">aerosol</span> vertical transport in complex environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Icar..260..246F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Icar..260..246F"><span id="translatedtitle">Dust devil <span class="hlt">height</span> and spacing with relation to the martian planetary boundary <span class="hlt">layer</span> thickness</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fenton, Lori K.; Lorenz, Ralph</p> <p>2015-11-01</p> <p>In most remote and unmonitored places, little is known about the characteristics of daytime turbulent activity. Few processes render the optically transparent atmospheres of Earth and Mars visible; put more plainly, without clever instruments it is difficult to "see the unseen". To address this, we present a pilot study of images of martian dust devils (DDs) testing the hypothesis that DD <span class="hlt">height</span> and spacing correlates with the thickness of the planetary boundary <span class="hlt">layer</span> (PBL), h. The survey includes Context Camera (CTX) images from a 580 × 590 km2 area (196-208°E, 30-40°N) in northern Amazonis Planitia, spanning ∼3.6 Mars Years (MY) from Ls = 134.55°, MY 28 (13 November 2006) to Ls = 358.5°, MY 31 (28 July 2013). DD activity follows a repeatable seasonal pattern similar to that found in previous surveys, with a distinct "on" season during local summer, beginning shortly before the northern spring equinox (Ls = 0°) and lasting until just after the northern fall equinox (Ls = 180°). DD <span class="hlt">heights</span> measured from shadow lengths varied considerably, with median values peaking at local midsummer. Modeled PBL <span class="hlt">heights</span>, constrained by those measured from radio occultation data, follow a similar seasonal trend, and correlation of the two suggests that the martian PBL thickness is approximately 5 times the median DD <span class="hlt">height</span>. These results compare favorably to the limited terrestrial data available. DD spacing was measured using nearest neighbor statistics, following the assumption that because convection cell widths have been measured to be ∼1.2 ± 0.2h (Willis, G.E., Deardorff, J.W. [1979]. J. Geophys. Res. 84(C1), 295-302), a preference for DD formation at vertices of convection cells intersections could be used to estimate the PBL <span class="hlt">height</span>. During local spring and summer, the DD average nearest neighbor (ANN) ranged from ∼1 to 2h, indicating that DD spacing does indeed correlate with PBL <span class="hlt">height</span>. However, this result is complicated by two factors: (1) convection cell</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121..529L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121..529L"><span id="translatedtitle">Double crests of peak <span class="hlt">height</span> in the equatorial ionospheric F2 <span class="hlt">layer</span> observed by COSMIC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luan, Xiaoli; Lei, Jiuhou; Dou, Xiankang; Dang, Tong</p> <p>2016-01-01</p> <p>For the first time, we report daytime double crests of peak <span class="hlt">height</span> (hmF2) in the F2 <span class="hlt">layer</span> based on the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) observations during 2007-2014. Evident double crests of hmF2 occurred at around ±10° geomagnetic latitude with a trough over the magnetic equator at low solar activity and at March equinox. This phenomenon is referred to as an equatorial <span class="hlt">height</span> anomaly (EHA) of the ionospheric F2 <span class="hlt">layer</span>. The double crests became less obvious at September equinox and disappeared at solstices. At solstices only one crest was observed in the summer hemisphere, which is probably associated with transequatorial neutral winds. In addition, the double EHA crests generally take place during 10:00-14:00 local times. Our results indicate that the EHA favors the conditions of strong vertical plasma drifts and weak transequatorial neutral winds during low solar activity. The EHA feature is reproduced by the Thermosphere Ionosphere Electrodynamics Global Circulation Model at March equinox and low solar activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1167155','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1167155"><span id="translatedtitle">“Lidar Investigations of <span class="hlt">Aerosol</span>, Cloud, and Boundary <span class="hlt">Layer</span> Properties Over the ARM ACRF Sites”</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ferrare, Richard; Turner, David</p> <p>2015-01-13</p> <p>Project goals; Characterize the <span class="hlt">aerosol</span> and ice vertical distributions over the ARM NSA site, and in particular to discriminate between elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> and ice clouds in optically thin scattering <span class="hlt">layers</span>; Characterize the water vapor and <span class="hlt">aerosol</span> vertical distributions over the ARM Darwin site, how these distributions vary seasonally, and quantify the amount of water vapor and <span class="hlt">aerosol</span> that is above the boundary <span class="hlt">layer</span>; Use the high temporal resolution Raman lidar data to examine how <span class="hlt">aerosol</span> properties vary near clouds; Use the high temporal resolution Raman lidar and Atmospheric Emitted Radiance Interferometer (AERI) data to quantify entrainment in optically thin continental cumulus clouds; and Use the high temporal Raman lidar data to continue to characterize the turbulence within the convective boundary <span class="hlt">layer</span> and how the turbulence statistics (e.g., variance, skewness) is correlated with larger scale variables predicted by models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Ge%26Ae..55..609S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Ge%26Ae..55..609S"><span id="translatedtitle">Global model SMF2 of the F2-<span class="hlt">layer</span> maximum <span class="hlt">height</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shubin, V. N.; Karpachev, A. T.; Telegin, V. A.; Tsybulya, K. G.</p> <p>2015-09-01</p> <p>A global model SMF2 (Satellite Model of F2 <span class="hlt">layer</span>) of the F2-<span class="hlt">layer</span> <span class="hlt">height</span> was created. For its creation, data from the topside sounding on board the Interkosmos-19 satellite, as well as the data of radio occultation measurements in the CHAMP, GRACE, and COSMIC experiments, were used. Data from a network of ground-based sounding stations were also additionally used. The model covers all solar activity levels, months, hours of local and universal time, longitudes, and latitudes. The model is a median one within the range of magnetic activity values K p< 3+. The spatial-temporal distribution of hmF2 in the new model is described by mutually orthogonal functions for which the attached Legendre polynomials are used. The temporal distribution is described by an expansion into a Fourier series in UT. The input parameters of the model are geographic coordinates, month, and time (UT or LT). The new model agrees well with the international model of the ionosphere IRI in places where there are many ground-based stations, and it more precisely describes the F2-<span class="hlt">layer</span> <span class="hlt">height</span> in places where they are absent: over the oceans and at the equator. Under low solar activity, the standard deviation in the SMF2 model does not exceed 14 km for all hours of the day, as compared to 26.6 km in the IRI-2012 model. The mean relative deviation is by approximately a factor of 4 less than that in the IRI model. Under high solar activity, the maximum standard deviations in the SMF2 model reach 25 km; however, in the IRI they are higher by a factor of ~2. The mean relative deviation is by a factor of ~2 less than in the IRI model. Thus, a hmF2 model that is more precise than IRI-2012 was created.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790031094&hterms=pollution+Marina&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dpollution%2BMarina','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790031094&hterms=pollution+Marina&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dpollution%2BMarina"><span id="translatedtitle">Properties of the stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span> studied with a one-dimensional computer model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Turco, R. P.; Toon, O. B.; Whitten, R. C.; Hamill, P.; Kiang, C. S.</p> <p>1978-01-01</p> <p><span class="hlt">Aerosol</span> particle effects are often neglected in theoretical studies of stratospheric phenomena. In reality, the particulate matter normally found above the tropopause may influence the terrestrial radiation balance, catalyze heterogeneous chemical interactions, and serve as a tracer of atmospheric motions. The paper proposes a one-dimensional model of the stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span>, and it is used to compare <span class="hlt">aerosol</span> theory with observational data. The model considers gaseous sulfur photochemistry and the physical <span class="hlt">aerosol</span> processes of nucleation, coagulation, sedimentation, and diffusion. Calculations of the effects on the <span class="hlt">aerosol</span> <span class="hlt">layer</span> of stratospheric injections of aluminum oxide particles by Space Shuttle engines and of sulfur dioxide molecules by volcanic activity are performed. The relation between measured <span class="hlt">aerosol</span> variability and changes in stratospheric air temperatures and vertical transport rates are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008ACP.....8.3705K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008ACP.....8.3705K"><span id="translatedtitle">Validation of <span class="hlt">aerosol</span> and cloud <span class="hlt">layer</span> structures from the space-borne lidar CALIOP using a ground-based lidar in Seoul, Korea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, S.-W.; Berthier, S.; Raut, J.-C.; Chazette, P.; Dulac, F.; Yoon, S.-C.</p> <p>2008-07-01</p> <p>We present initial validation results of the space-borne lidar CALIOP onboard CALIPSO satellite using coincidental observations from a ground-based lidar in Seoul National University (SNU), Seoul, Korea (37.46° N, 126.95° E). We analyze six selected cases between September 2006 and February 2007, including 3 daytime and 3 night-time observations and covering different types of clear and cloudy atmospheric conditions. Apparent scattering ratios calculated from the two lidar measurements of total attenuated backscatter at 532 nm show similar <span class="hlt">aerosol</span> and cloud <span class="hlt">layer</span> structures both under cloud-free conditions and in cases of multiple <span class="hlt">aerosol</span> <span class="hlt">layers</span> underlying semi-transparent cirrus clouds. Agreement on top and base <span class="hlt">heights</span> of cloud and <span class="hlt">aerosol</span> <span class="hlt">layers</span> is generally within 0.10 km, particularly during night-time. This result confirms that the CALIPSO science team algorithms for the discrimination of cloud and <span class="hlt">aerosol</span> as well as for the detection of <span class="hlt">layer</span> top and base altitude provide reliable information in such atmospheric conditions. This accuracy of the planetary boundary <span class="hlt">layer</span> top <span class="hlt">height</span> under cirrus cloud appears, however, limited during daytime. Under thick cloud conditions, however, information on the cloud top (bottom) <span class="hlt">height</span> only is reliable from CALIOP (ground-based lidar) due to strong signal attenuations. However, simultaneous space-borne CALIOP and ground-based SNU lidar (SNU-L) measurements complement each other and can be combined to provide full information on the vertical distribution of <span class="hlt">aerosols</span> and clouds. An <span class="hlt">aerosol</span> backscatter-to-extinction ratio (BER) estimated from lidar and sunphotometer synergy at the SNU site during the CALIOP overpass is assessed to be 0.023±0.004 sr-1 (i.e. a lidar ratio of 43.2±6.2 sr) from CALIOP and 0.027±0.006 sr-1 (37.4±7.2 sr) from SNU-L. For <span class="hlt">aerosols</span> within the planetary boundary <span class="hlt">layer</span> under cloud-free conditions, the <span class="hlt">aerosol</span> extinction profiles from both lidars are in agreement within about 0.02 km-1. Under semi</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160007812','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160007812"><span id="translatedtitle">The Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> Through Satellite and Balloon-Borne Measurements Combined With Modeling Approaches</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vernier, J.-P.; Fairlie, T. D.; Natarajan, M.; Wegner, T.; Baker, N.; Crawford, J.; Moore, J.; Deshler, T.; Gadhavi, H.; Jayaraman, A.; Pandit, A.; Raj, A.; Kumar, H.; Kumar, S.; Singh, A.; Vignelles, D.; Stenchikov, G.; Wiehold, F.; Bian, J.</p> <p>2016-01-01</p> <p>The Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span>-ATAL is a confined area of enhanced <span class="hlt">aerosol</span> associated Summer Asia Monsoon spanning from the E. Med Sea to W. China. It essentially extends from top of convective outflow over much of SE Asia Existence recognize through CALIPSO observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1990abl..book..109K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1990abl..book..109K&link_type=ABSTRACT"><span id="translatedtitle">Complex measurements of <span class="hlt">aerosol</span> and ion characteristics in the atmospheric boundary <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kikas, Iu. E.; Kolomiets, S. M.; Kornienko, V. I.; Mirme, A. A.; Sal'm, Ia. I.; Sergeev, I. Ia.; Tammet, Kh. F.</p> <p></p> <p>Results of a comprehensive study of the characteristics of atmospheric ions and <span class="hlt">aerosols</span> in the boundary <span class="hlt">layer</span> during the summer season are reported. A study is also made of the kinetics of <span class="hlt">aerosol</span> formation under conditions of high artificial ionization of the air by alpha and UV radiation. A high degree of correlation is shown to exist between atmospheric concentrations of medium ions and fine (less than 0.01 micron) <span class="hlt">aerosol</span>. The results obtained support the radiation-chemical mechanism of <span class="hlt">aerosol</span> formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H13L..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H13L..03S"><span id="translatedtitle">Empirical relationships between soil moisture, albedo, and the planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span>: a two-<span class="hlt">layer</span> bucket model approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sanchez-Mejia, Z. M.; Papuga, S. A.</p> <p>2013-12-01</p> <p>In semiarid regions, where water resources are limited and precipitation dynamics are changing, understanding land surface-atmosphere interactions that regulate the coupled soil moisture-precipitation system is key for resource management and planning. We present a modeling approach to study soil moisture and albedo controls on planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> (PBLh). We used data from the Santa Rita Creosote Ameriflux site and Tucson Airport atmospheric sounding to generate empirical relationships between soil moisture, albedo and PBLh. We developed empirical relationships and show that at least 50% of the variation in PBLh can be explained by soil moisture and albedo. Then, we used a stochastically driven two-<span class="hlt">layer</span> bucket model of soil moisture dynamics and our empirical relationships to model PBLh. We explored soil moisture dynamics under three different mean annual precipitation regimes: current, increase, and decrease, to evaluate at the influence on soil moisture on land surface-atmospheric processes. While our precipitation regimes are simple, they represent future precipitation regimes that can influence the two soil <span class="hlt">layers</span> in our conceptual framework. For instance, an increase in annual precipitation, could impact on deep soil moisture and atmospheric processes if precipitation events remain intense. We observed that the response of soil moisture, albedo, and the PBLh will depend not only on changes in annual precipitation, but also on the frequency and intensity of this change. We argue that because albedo and soil moisture data are readily available at multiple temporal and spatial scales, developing empirical relationships that can be used in land surface - atmosphere applications are of great value.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ACP....16.2459T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ACP....16.2459T"><span id="translatedtitle">Mixing <span class="hlt">layer</span> <span class="hlt">height</span> and its implications for air pollution over Beijing, China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, Guiqian; Zhang, Jinqiang; Zhu, Xiaowan; Song, Tao; Münkel, Christoph; Hu, Bo; Schäfer, Klaus; Liu, Zirui; Zhang, Junke; Wang, Lili; Xin, Jinyuan; Suppan, Peter; Wang, Yuesi</p> <p>2016-03-01</p> <p>The mixing <span class="hlt">layer</span> is an important meteorological factor that affects air pollution. In this study, the atmospheric mixing <span class="hlt">layer</span> <span class="hlt">height</span> (MLH) was observed in Beijing from July 2009 to December 2012 using a ceilometer. By comparison with radiosonde data, we found that the ceilometer underestimates the MLH under conditions of neutral stratification caused by strong winds, whereas it overestimates the MLH when sand-dust is crossing. Using meteorological, PM2.5, and PM10 observational data, we screened the observed MLH automatically; the ceilometer observations were fairly consistent with the radiosondes, with a correlation coefficient greater than 0.9. Further analysis indicated that the MLH is low in autumn and winter and high in spring and summer in Beijing. There is a significant correlation between the sensible heat flux and MLH, and the diurnal cycle of the MLH in summer is also affected by the circulation of mountainous plain winds. Using visibility as an index to classify the degree of air pollution, we found that the variation in the sensible heat and buoyancy term in turbulent kinetic energy (TKE) is insignificant when visibility decreases from 10 to 5 km, but the reduction of shear term in TKE is near 70 %. When visibility decreases from 5 to 1 km, the variation of the shear term in TKE is insignificant, but the decrease in the sensible heat and buoyancy term in TKE is approximately 60 %. Although the correlation between the daily variation of the MLH and visibility is very poor, the correlation between them is significantly enhanced when the relative humidity increases beyond 80 %. This indicates that humidity-related physicochemical processes is the primary source of atmospheric particles under heavy pollution and that the dissipation of atmospheric particles mainly depends on the MLH. The presented results of the atmospheric mixing <span class="hlt">layer</span> provide useful empirical information for improving meteorological and atmospheric chemistry models and the forecasting</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9640E..0OS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9640E..0OS"><span id="translatedtitle">Mixing <span class="hlt">layer</span> <span class="hlt">height</span> measurements determines influence of meteorology on air pollutant concentrations in urban area</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schäfer, Klaus; Blumenstock, Thomas; Bonn, Boris; Gerwig, Holger; Hase, Frank; Münkel, Christoph; Nothard, Rainer; von Schneidemesser, Erika</p> <p>2015-10-01</p> <p>Mixing <span class="hlt">layer</span> <span class="hlt">height</span> (MLH) is a key parameter to determine the influence of meteorological parameters upon air pollutants such as trace gas species and particulate concentrations near the surface. Meteorology, and MLH as a key parameter, affect the budget of emission source strengths, deposition, and accumulation. However, greater possibilities for the application of MLH data have been identified in recent years. Here, the results of measurements in Berlin in 2014 are shown and discussed. The concentrations of NO, NO2, O3, CO, PM1, PM2.5, PM10 and about 70 volatile organic compounds (anthropogenic and biogenic of origin) as well as particle size distributions and contributions of SOA and soot species to PM were measured at the urban background station of the Berlin air quality network (BLUME) in Nansenstr./Framstr., Berlin-Neukölln. A Vaisala ceilometer CL51, which is a commercial mini-lidar system, was applied at that site to detect the <span class="hlt">layers</span> of the lower atmosphere in real time. Special software for these ceilometers with MATLAB provided routine retrievals of MLH from vertical profiles of laser backscatter data. Five portable Bruker EM27/SUN FTIR spectrometers were set up around Berlin to detect column averaged abundances of CO2 and CH4 by solar absorption spectrometry. Correlation analyses were used to show the coupling of temporal variations of trace gas compounds and PM with MLH. Significant influences of MLH upon NO, NO2, PM10, PM2.5, PM1 and toluene (marker for traffic emissions) concentrations as well as particle number concentrations in the size modes 70 - 100 nm, 100 - 200 nm and 200 - 500 nm on the basis of averaged diurnal courses were found. Further, MLH was taken as important auxiliary information about the development of the boundary <span class="hlt">layer</span> during each day of observations, which was required for the proper estimation of CO2 and CH4 source strengths from Berlin on the basis of atmospheric column density measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950004708','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950004708"><span id="translatedtitle">Effect of stratospheric <span class="hlt">aerosol</span> <span class="hlt">layers</span> on the TOMS/SBUV ozone retrieval</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Torres, O.; Ahmad, Zia; Pan, L.; Herman, J. R.; Bhartia, P. K.; Mcpeters, R.</p> <p>1994-01-01</p> <p>An evaluation of the optical effects of stratospheric <span class="hlt">aerosol</span> <span class="hlt">layers</span> on total ozone retrieval from space by the TOMS/SBUV type instruments is presented here. Using the Dave radiative transfer model we estimate the magnitude of the errors in the retrieved ozone when polar stratospheric clouds (PSC's) or volcanic <span class="hlt">aerosol</span> <span class="hlt">layers</span> interfere with the measurements. The largest errors are produced by optically thick water ice PSC's. Results of simulation experiments on the effect of the Pinatubo <span class="hlt">aerosol</span> cloud on the Nimbus-7 and Meteor-3 TOMS products are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.6011R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.6011R&link_type=ABSTRACT"><span id="translatedtitle">Secondary <span class="hlt">Aerosol</span> Formation in the planetary boundary <span class="hlt">layer</span> observed by <span class="hlt">aerosol</span> mass spectrometry on a Zeppelin NT</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rubach, Florian; Trimborn, Achim; Mentel, Thomas; Wahner, Andreas; Zeppelin Pegasos-Team 2012</p> <p>2014-05-01</p> <p>The airship Zeppelin NT is an airborne platform capable of flying at low speed throughout the entire planetary boundary <span class="hlt">layer</span> (PBL). In combination with the high scientific payload of more than 1 ton, the Zeppelin is an ideal platform to study regional processes in the lowest <span class="hlt">layers</span> of the atmosphere with high spatial resolution. Atmospheric <span class="hlt">aerosol</span> as a medium long lived tracer substance is of particular interest due to its influence on the global radiation budget. Due its lifetime of up to several days secondaray <span class="hlt">aerosol</span> at a certain location can result from local production or from transport processes. For <span class="hlt">aerosol</span> measurements on a Zeppelin, a High-Resolution Time-of-Flight <span class="hlt">Aerosol</span> Mass spectrometer (DeCarlo et al, 2006) was adapted to the requirements posed by an airborne platform. A weight reduction of over 20 % compared to the commercial instrument was achieved, while space occupation and footprint were each reduced by over 25 %. Within the PEGASOS project, the instrument was part of 10 measurement flight days over the course of seven weeks. Three flights were starting from Rotterdam, NL, seven flights were starting from Ozzano in the Po Valley, IT. Flight patterns included vertical profiles to study the dynamics of the PBL and cross sections through regions of interest to shed light on local production and transport processes. Analysis of data from transects between the Apennin and San Pietro Capofiume in terms of "residence time of air masses in the Po valley" indicates that <span class="hlt">aerosol</span> nitrate has only local sources while <span class="hlt">aerosol</span> sulfate is dominated by transport. The organic <span class="hlt">aerosol</span> component has significant contributions of both processes. The local prodcution yields are commensurable with imultaneously observed precursor concentrations and oxidant levels. The PEGASOS project is funded by the European Commission under the Framework Programme 7 (FP7-ENV-2010-265148). DeCarlo, P.F. et al (2006), Anal. Chem., 78, 8281-8289.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.3037W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.3037W"><span id="translatedtitle">Observed Variability of Global Atmospheric Mixing <span class="hlt">Layer</span> <span class="hlt">Height</span> from 1971 to 2014</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Xiaoyan; Wang, Kaicun</p> <p>2015-04-01</p> <p>It is important to determine the mixing <span class="hlt">layer</span> <span class="hlt">height</span> (MLH) for understanding the transport process in the troposphere, weather prediction, and climate monitoring. MLH is a key parameter in air pollution models which determines the volume available for pollutants to dispersion. The long-term variation of MLH can drive the change of surface air quality. Many methods have been proposed to estimate MLH from the temperature or atmospheric composition profiles provided by radiosonde and remote sounding systems. Radiosonde data are usually considered as a reference by other methods owing to its long-term history and direct observation. However, disagreements exist between MLHs derived from different variable profiles of radiosonde data. In this study, a method integrating the information of potential temperature, relative humidity, specific humidity, atmospheric refractivity and the effect of cloud on the boundary <span class="hlt">layer</span> turbulence was applied to the global radiosonde data to generate long-term variation of the global MLH from 1971 to 2014. The radiosonde observations were released by the Integrated Global Radiosonde Archive (IGRA) of National Climatic Data Center (NCDC). The MLHs in the North America are fairly deep, with an average value between 1800 and 2200 m, however, the Europe and the Eastern Asia have shallow MLHs between 1200 and 1500 m. The majority of the North America and Australia stations showed a negative trend during the period of 1971 to 2014, while, for the Europe and Japan, the MLHs increased over time. The MLH had a negative correlation with surface relative humidity and a positive association with surface air temperature. Besides the effect of thermodynamic factors, the dynamical factors including the surface wind speed and its shear in the boundary <span class="hlt">layer</span> influence the development of the boundary <span class="hlt">layer</span>. However, there is no significant correlation between the surface wind speeds and MLH in this study. Weak negative association was found between</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160005988','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160005988"><span id="translatedtitle">The Effect of Backward-Facing Step <span class="hlt">Height</span> on Instability Growth and Breakdown in Swept Wing Boundary-<span class="hlt">Layer</span> Transition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Eppink, Jenna L.; Wlezien, Richard W.; King, Rudolph A.; Choudhari, Meelan</p> <p>2015-01-01</p> <p>A low-speed experiment was performed on a swept at plate model with an imposed pressure gradient to determine the effect of a backward-facing step on transition in a stationary-cross flow dominated flow. Detailed hot-wire boundary-<span class="hlt">layer</span> measurements were performed for three backward-facing step <span class="hlt">heights</span> of approximately 36, 45, and 49% of the boundary-<span class="hlt">layer</span> thickness at the step. These step <span class="hlt">heights</span> correspond to a subcritical, nearly-critical, and critical case. Three leading-edge roughness configurations were tested to determine the effect of stationary-cross flow amplitude on transition. The step caused a local increase in amplitude of the stationary cross flow for the two larger step <span class="hlt">height</span> cases, but farther downstream the amplitude decreased and remained below the baseline amplitude. The smallest step caused a slight local decrease in amplitude of the primary stationary cross flow mode, but the amplitude collapsed back to the baseline case far downstream of the step. The effect of the step on the amplitude of the primary cross flow mode increased with step <span class="hlt">height</span>, however, the stationary cross flow amplitudes remained low and thus, stationary cross flow was not solely responsible for transition. Unsteady disturbances were present downstream of the step for all three step <span class="hlt">heights</span>, and the amplitudes increased with increasing step <span class="hlt">height</span>. The only exception is that the lower frequency (traveling crossflow-like) disturbance was not present in the lowest step <span class="hlt">height</span> case. Positive and negative spikes in instantaneous velocity began to occur for the two larger step <span class="hlt">height</span> cases and then grew in number and amplitude downstream of reattachment, eventually leading to transition. The number and amplitude of spikes varied depending on the step <span class="hlt">height</span> and cross flow amplitude. Despite the low amplitude of the disturbances in the intermediate step <span class="hlt">height</span> case, breakdown began to occur intermittently and the flow underwent a long transition region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT........99J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT........99J"><span id="translatedtitle"><span class="hlt">Aerosol</span>-cloud-precipitation interactions in the trade wind boundary <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jung, Eunsil</p> <p></p> <p>This dissertation includes an overview of <span class="hlt">aerosol</span>, cloud, and precipitation properties associated with shallow marine cumulus clouds observed during the Barbados <span class="hlt">Aerosol</span> Cloud Experiment (BACEX, March-April 2010) and a discussion of their interactions. The principal observing platform for the experiment was the Cooperative Institute for Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter (TO) research aircraft that was equipped with <span class="hlt">aerosol</span>, cloud, and precipitation probes, standard meteorological instruments, and a up-looking cloud radar. The temporal variations and vertical distributions of <span class="hlt">aerosols</span> observed on the 15 flights show a wide range of <span class="hlt">aerosol</span> conditions that include the most intense African dust event observed at the Barbados surface site during all of 2010. An average CCN varied from 50 cm-3 to 800 cm -3 at super-saturation of 0.6 %, for example. The 10-day backward trajectories show that three distinctive air masses (originality of air mass as well as the vertical structure) dominate over the Eastern Caribbean (e.g., typical maritime air mass, Saharan Air <span class="hlt">Layer</span> (SAL), Middle latitude dry air) with characteristic <span class="hlt">aerosol</span> vertical structures. Many clouds in various phases of growth during BACEX are sampled. The maximum cloud depth observed is about less than 3 km and in most of the clouds is less than 1 km. Two types of precipitation features were observed for the shallow marine cumulus clouds with different impacts on boundary <span class="hlt">layer</span>. In one, precipitation shafts are observed to emanate from the cloud base with evaporation in the sub-cloud <span class="hlt">layer</span> (stabilize the sub-cloud <span class="hlt">layer</span>). In the other, precipitation shafts emanate mainly near the cloud top on the downshear side of the cloud and evaporate in the cloud <span class="hlt">layer</span>, leading to destabilizing the cloud <span class="hlt">layer</span> and providing moisture to the <span class="hlt">layer</span>. Only 42-44 % of clouds sampled were purely non-precipitating throughout the clouds; the remainder of the clouds showed precipitation somewhere in the cloud</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20100024393&hterms=elastic+averaging&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delastic%2Baveraging','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20100024393&hterms=elastic+averaging&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delastic%2Baveraging"><span id="translatedtitle">Fully Automated Detection of Cloud and <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> in the CALIPSO Lidar Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vaughan, Mark A.; Powell, Kathleen A.; Kuehn, Ralph E.; Young, Stuart A.; Winker, David M.; Hostetler, Chris A.; Hunt, William H.; Liu, Zhaoyan; McGill, Matthew J.; Getzewich, Brian J.</p> <p>2009-01-01</p> <p>Accurate knowledge of the vertical and horizontal extent of clouds and <span class="hlt">aerosols</span> in the earth s atmosphere is critical in assessing the planet s radiation budget and for advancing human understanding of climate change issues. To retrieve this fundamental information from the elastic backscatter lidar data acquired during the Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission, a selective, iterated boundary location (SIBYL) algorithm has been developed and deployed. SIBYL accomplishes its goals by integrating an adaptive context-sensitive profile scanner into an iterated multiresolution spatial averaging scheme. This paper provides an in-depth overview of the architecture and performance of the SIBYL algorithm. It begins with a brief review of the theory of target detection in noise-contaminated signals, and an enumeration of the practical constraints levied on the retrieval scheme by the design of the lidar hardware, the geometry of a space-based remote sensing platform, and the spatial variability of the measurement targets. Detailed descriptions are then provided for both the adaptive threshold algorithm used to detect features of interest within individual lidar profiles and the fully automated multiresolution averaging engine within which this profile scanner functions. The resulting fusion of profile scanner and averaging engine is specifically designed to optimize the trade-offs between the widely varying signal-to-noise ratio of the measurements and the disparate spatial resolutions of the detection targets. Throughout the paper, specific algorithm performance details are illustrated using examples drawn from the existing CALIPSO dataset. Overall performance is established by comparisons to existing <span class="hlt">layer</span> <span class="hlt">height</span> distributions obtained by other airborne and space-based lidars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1043105','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1043105"><span id="translatedtitle">Application of the CALIOP <span class="hlt">Layer</span> Product to Evaluate the Vertical Distribution of <span class="hlt">Aerosols</span> Estimated by Global Models: AeroCom Phase I Results</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Koffi, Brigitte; Schultz, Michael; Breon, Francois-Marie; Griesfeller, Jan; Winker, D.; Balkanski, Y.; Bauer, Susanne E.; Berntsen, T.; Chin, Mian; Collins, William D.; Dentener, Frank; Diehl, Thomas; Easter, Richard C.; Ghan, Steven J.; Ginoux, P.; Gong, S.; Horowitz, L.; Iversen, T.; Kirkevag, A.; Koch, Dorothy; Krol, Maarten; Myhre, G.; Stier, P.; Takemura, T.</p> <p>2012-05-19</p> <p>The CALIOP (Cloud-<span class="hlt">Aerosol</span> Lidar with Orthogonal Polarization) <span class="hlt">layer</span> product is used for a multimodel evaluation of the vertical distribution of <span class="hlt">aerosols</span>. Annual and seasonal <span class="hlt">aerosol</span> extinction profiles are analyzed over 13 sub-continental regions representative of industrial, dust, and biomass burning pollution, from CALIOP 2007-2009 observations and from AeroCom (<span class="hlt">Aerosol</span> Comparisons between Observations and Models) 2000 simulations. An extinction mean <span class="hlt">height</span> diagnostic (Z{sub a}) is defined to quantitatively assess the models performance. It is calculated over the 0-6 km and 0-10 km altitude ranges by weighting the altitude of each 100 m altitude <span class="hlt">layer</span> by its <span class="hlt">aerosol</span> extinction coefficient. The mean extinction profiles derived from CALIOP <span class="hlt">layer</span> products provide consistent regional and seasonal specificities and a low inter-annual variability. While the outputs from most models are significantly correlated with the observed Z{sub a} climatologies, some do better than others, and 2 of the 12 models perform particularly well in all seasons. Over industrial and maritime regions, most models show higher Z{sub a} than observed by CALIOP, whereas over the African and Chinese dust source regions, Z{sub a} is underestimated during Northern Hemisphere Spring and Summer. The positive model bias in Z{sub a} is mainly due to an overestimate of the extinction above 6 km. Potential CALIOP and model limitations, and methodological factors that might contribute to the differences are discussed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140005807','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140005807"><span id="translatedtitle">Application of the CALIOP <span class="hlt">Layer</span> Product to Evaluate the Vertical Distribution of <span class="hlt">Aerosols</span> Estimated by Global Models: AeroCom Phase I Results</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Koffi, Brigitte; Schulz, Michael; Breon, Francois-Marie; Griesfeller, Jan; Winker, David; Balkanski, Yves; Bauer, Susanne; Berntsen, Terje; Chin, Mian; Collins, William D.; Dentener, Frank; Diehl, Thomas; Easter, Richard; Ghan, Steven; Gimoux, Paul; Gong, Sunling; Horowitz, Larry W.; Iversen, Trond; Kirkevag, Alf; Koch, Dorothy; Krol, Maarten; Myhre, Gunnar; Stier, Philip; Takemura, Toshihiko</p> <p>2012-01-01</p> <p>The CALIOP (Cloud-<span class="hlt">Aerosol</span> Lidar with Orthogonal Polarization) <span class="hlt">layer</span> product is used for a multimodel evaluation of the vertical distribution of <span class="hlt">aerosols</span>. Annual and seasonal <span class="hlt">aerosol</span> extinction profiles are analyzed over 13 sub-continental regions representative of industrial, dust, and biomass burning pollution, from CALIOP 2007-2009 observations and from AeroCom (<span class="hlt">Aerosol</span> Comparisons between Observations and Models) 2000 simulations. An extinction mean <span class="hlt">height</span> diagnostic (Z-alpha) is defined to quantitatively assess the models' performance. It is calculated over the 0-6 km and 0-10 km altitude ranges by weighting the altitude of each 100 m altitude <span class="hlt">layer</span> by its <span class="hlt">aerosol</span> extinction coefficient. The mean extinction profiles derived from CALIOP <span class="hlt">layer</span> products provide consistent regional and seasonal specificities and a low inter-annual variability. While the outputs from most models are significantly correlated with the observed Z-alpha climatologies, some do better than others, and 2 of the 12 models perform particularly well in all seasons. Over industrial and maritime regions, most models show higher Z-alpha than observed by CALIOP, whereas over the African and Chinese dust source regions, Z-alpha is underestimated during Northern Hemisphere Spring and Summer. The positive model bias in Z-alpha is mainly due to an overestimate of the extinction above 6 km. Potential CALIOP and model limitations, and methodological factors that might contribute to the differences are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACPD...1528249T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACPD...1528249T"><span id="translatedtitle">Mixing <span class="hlt">layer</span> <span class="hlt">height</span> and the implications for air pollution over Beijing, China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tang, G.; Zhang, J.; Münkel, C.; Song, T.; Hu, B.; Schäfer, K.; Liu, Z.; Xin, J.; Suppan, P.; Wang, Y.</p> <p>2015-10-01</p> <p>The mixing <span class="hlt">layer</span> is an important meteorological factor that affects atmospheric pollution. A study of atmospheric pollution in the Beijing area was performed from July 2009 to December 2012, using a ceilometer, to observe and study the atmospheric mixing <span class="hlt">layer</span> <span class="hlt">height</span> (MLH). Based on a comparison and validation of multiple types of data, we evaluated the quality of the MLH data as observed by the ceilometer and found that the ceilometer underestimates MLH during neutral stratification caused by strong winds, whereas it overestimates MLH during dust crossing. By combining conventional meteorological data and PM2.5 and PM10 observational data, we screened the observational results for the MLH, and the ceilometer observations were fairly consistent with the meteorological radiosonde profile results. The correlation coefficient is more than 0.9, and the effective rate of acquired data is near 80 %. Further analysis of the variation in the MLH indicates that the MLH in the Beijing area exhibits the feature of being low in autumn and winter and being high in spring and summer. There is a significant correlation between the variation in the MLH and the sensible heat flux, whereas the diurnal variation in the mixing <span class="hlt">layer</span> during summer is affected by the circulation of mountainous plain winds. By applying visibility as the index for the classification of atmospheric pollution degree, it is found that in comparison with a clear day, the variation of sensible heat and buoyancy term in turbulent kinetic energy (TKE) of a slight haze day is insignificant, but the reduction of shear term in TKE is near 70 % when visibility decreased from 10 to 5 km; in comparison with the slight haze day, the variation of shear term in TKE of medium and heavy haze days is insignificant, but the declination of sensible heat and buoyancy term in TKE are about 60 % when visibility decreased from 5 to 1 km. Although the correlation between the daily variation of MLH and visibility is very poor, the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H21C1050B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H21C1050B"><span id="translatedtitle"><span class="hlt">Aerosols</span> in the Convective Boundary <span class="hlt">Layer</span>: Radiation Effects on the Coupled Land-Atmosphere System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barbaro, E.; Vila-Guerau Arellano, J.; Ouwersloot, H. G.; Schroter, J.; Donovan, D. P.; Krol, M. C.</p> <p>2013-12-01</p> <p>We investigate the responses of the surface energy budget and the convective boundary-<span class="hlt">layer</span> (CBL) dynamics to the presence of <span class="hlt">aerosols</span> using a combination of observations and numerical simulations. A detailed observational dataset containing (thermo)dynamic variables observed at CESAR (Cabauw Experimental Site for Atmospheric Research) and <span class="hlt">aerosol</span> information from the European Integrated Project on <span class="hlt">Aerosol</span>, Cloud, Climate, and Air Quality Interactions (IMPACT/EUCAARI) campaign is employed to design numerical experiments reproducing two prototype clear-sky days characterized by: (i) a well-mixed residual <span class="hlt">layer</span> above a ground inversion and (ii) a continuously growing CBL. A large-eddy simulation (LES) model and a mixed-<span class="hlt">layer</span> (MXL) model, both coupled to a broadband radiative transfer code and a land-surface model, are used to study the impacts of <span class="hlt">aerosol</span> scattering and absorption of shortwave radiation on the land-atmosphere system. We successfully validate our model results using the measurements of (thermo)dynamic variables and <span class="hlt">aerosol</span> properties for the two different CBL prototypes studied here. Our findings indicate that in order to reproduce the observed surface energy budget and CBL dynamics, information of the vertical structure and temporal evolution of the <span class="hlt">aerosols</span> is necessary. Given the good agreement between the LES and the MXL model results, we use the MXL model to explore the <span class="hlt">aerosol</span> effect on the land-atmosphere system for a wide range of optical depths and single scattering albedos. Our results show that higher loads of <span class="hlt">aerosols</span> decrease irradiance, imposing an energy restriction at the surface. Over the studied well-watered grassland, <span class="hlt">aerosols</span> reduce the sensible heat flux more than the latent heat flux. As a result, <span class="hlt">aerosols</span> increase the evaporative fraction. Moreover, <span class="hlt">aerosols</span> also delay the CBL morning onset and anticipate its afternoon collapse. If also present above the CBL during the morning transition, <span class="hlt">aerosols</span> maintain a persistent near</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5642829','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5642829"><span id="translatedtitle">NO sub 2 overnight decay and <span class="hlt">layer</span> <span class="hlt">height</span> at Halley Bay, Antarctica</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Keys, J.G. ); Gardiner, B.G. )</p> <p>1991-04-01</p> <p>Ground-based measurements of stratospheric slant column NO{sub 2} amounts made at Halley Bay, Antarctica in 1987 are compared with ozone and temperature profiles from balloon-borne sondes. Sunrise-to-sunset (am/pm) ratios of NO{sub 2} have been calculated in autumn and spring by using the sonde data in conjunction with a simple photochemical model for the conversion of NO{sub 2} to N{sub 2}O{sub 5}. These calculations can be reconciled with the spectrometric measurements of column NO{sub 2}, provided that the bulk of the NO{sub 2} <span class="hlt">layer</span> is assumed to lie at a <span class="hlt">height</span> of about 25km. The small amounts of NO{sub 2} that are present in the stratospheric column during the first 6 weeks of spring are therefore confined to altitudes above the ozone depletion region. Slow recovery of the NO{sub 2} column in spring compared with the rate of its decline in autumn indicates slow photolysis of depleted levels of N{sub 2}O{sub 5} inside the polar vortex.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15.2154L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15.2154L&link_type=ABSTRACT"><span id="translatedtitle">The study of <span class="hlt">aerosol</span> and ozone measurements in lower boundary <span class="hlt">layer</span> with UAV helicopter platform</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Po-hsiung; Chen, Wen-nai</p> <p>2013-04-01</p> <p>This study describes the <span class="hlt">aerosol</span> and ozone measurement in the lower atmospheric boundary <span class="hlt">layer</span> of highly polluted region at Kao-hsiung, Taiwan with a small unmanned aerial vehicle (UAV) helicopter platform. This UAV helicopter, modified from Gaui-X7 electronic-power model helicopter with autopilot AHRS (Altitude-Head-Reference System) kit, has fast climb speed up to 700 m <span class="hlt">height</span> and keeps stable status for atmospheric measurements in five-minute fly leg. Several quick-replaced battery packages are ready on ground for field intensive observation. The payload rack under this UAV helicopter carries a micro-Aethalometer (black carbon concentration), ozone meter, temperature-humidity sensor, barometer and a time-lapse digital camera. The field measurement site closes to Linyuan Petrochemical Industrial Park, where is one of the heavy polluted regions in Taiwan. Balloon-borne Vaisala RS-92 radiosonde and CL31 Lidar Ceilometer are used to provide the background of the atmosphere at the same time. More data analysis measured by UAV helicopter and its potential application will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ACPD...12.2355W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ACPD...12.2355W"><span id="translatedtitle"><span class="hlt">Aerosol</span> observations and growth rates in the tropical tropopause <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Waddicor, D. A.; Vaughan, G.; Choularton, T. W.; Bower, K. N.; Coe, H.; Gallagher, M.; Williams, P. I.; Flynn, M.; Volz-Thomas, A.; Pätz, W.; Isaac, P.; Hacker, J.; Arnold, F.; Schlager, H.; Whiteway, J. A.</p> <p>2012-01-01</p> <p>We present a case study of Aitken and accumulation mode <span class="hlt">aerosol</span> observed downwind of the anvils of deep tropical thunderstorms. The measurements were made by condensation nuclei counters flown on the Egrett high-altitude aircraft from Darwin during the ACTIVE campaign, in monsoon conditions producing widespread convection over land and ocean. Maximum measured concentrations of <span class="hlt">aerosol</span> in the size range 10-100 nm were 25 000 cm-3 STP. By calculating back-trajectories from the observations, and projecting on to infrared satellite images, the time since the air exited cloud was estimated. In this way a time scale of ~ 3-4 h was derived for the 10-100 nm <span class="hlt">aerosol</span> concentration to reach its peak. We examine the hypothesis that the growth in <span class="hlt">aerosol</span> concentrations can be explained by production of sulphuric acid from SO2 followed by particle nucleation and coagulation. Estimates of the sulphuric acid production rate show that the observations are only consistent with this hypothesis if the particles coagulate to sizes > 10 nm much more quickly than is suggested by current theory. Alternatively, other condensible gases (possibly organic) drive the growth of <span class="hlt">aerosol</span> particles in the TTL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A31D3057B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A31D3057B"><span id="translatedtitle">Radiative Impact of Observed and Simulated <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> Over the East Coast of North America</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berg, L. K.; Fast, J. D.; Burton, S. P.; Chand, D.; Comstock, J. M.; Ferrare, R. A.; Hair, J. W.; Hostetler, C. A.; Hubbe, J. M.; Kassianov, E.; Rogers, R. R.; Sedlacek, A. J., III; Shilling, J. E.; Tomlinson, J. M.; Wilson, J. M.; Zelenyuk, A.</p> <p>2014-12-01</p> <p>The vertical distribution of particles in the atmospheric column can have a large impact on the radiative forcing and cloud microphysics. A recent climatology constructed using data collected by the Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) suggests elevated <span class="hlt">layers</span> of <span class="hlt">aerosol</span> are quite common near the North American east coast during both winter and summer. The Two-Column <span class="hlt">Aerosol</span> Project (TCAP), conducted from June 2012 through June 2013, was a unique study utilizing both in situ and remotely sensed measurements designed to provide a comprehensive data set that can be used to investigate science questions related to <span class="hlt">aerosol</span> radiative forcing and the vertical distribution of <span class="hlt">aerosol</span>. The study sampled the atmosphere at a number of altitudes within two atmospheric columns; one located near the coast of North America (over Cape Cod, MA) and a second over the Atlantic Ocean several hundred kilometers from the coast. TCAP included the yearlong deployment of the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) located at the base of the Cape Cod column, as well as summer and winter aircraft intensive observation periods (IOPs) using the ARM Aerial Facility. One important finding from the TCAP summer IOP is the relatively common occurrence (during four of the six nearly cloud-free flights) of elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> in both the Cape Cod and maritime columns that were detected using the nadir pointing second-generation NASA Langley Research Center High-Spectral Resolution Lidar (HSRL-2). These elevated <span class="hlt">layers</span> contributed up to 60% of the total observed <span class="hlt">aerosol</span> optical depth (AOD). Many of these <span class="hlt">layers</span> were also intercepted by the aircraft configured for in situ sampling, and the <span class="hlt">aerosol</span> in the <span class="hlt">layers</span> was found to have increased amounts of biomass burning material and nitrate compared to <span class="hlt">aerosol</span> found near the surface. Both the in situ and remote sensing observations have been compared to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19690000653','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19690000653"><span id="translatedtitle">Pulse-<span class="hlt">height</span> defect due to electron interaction in dead <span class="hlt">layers</span> of Ge/Li/ gamma-ray detectors</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Larsen, R. N.; Strauss, M. G.</p> <p>1969-01-01</p> <p>Study shows the pulse-<span class="hlt">height</span> degradation of gamma ray spectra in germanium/lithium detectors to be due to electron interaction in the dead <span class="hlt">layers</span> that exist in all semiconductor detectors. A pulse shape discrimination technique identifies and eliminates these defective pulses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26699197','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26699197"><span id="translatedtitle">Effects of Ga-Te interface <span class="hlt">layer</span> on the potential barrier <span class="hlt">height</span> of CdTe/GaAs heterointerface.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xi, Shouzhi; Jie, Wanqi; Zha, Gangqiang; Yuan, Yanyan; Wang, Tao; Zhang, Wenhua; Zhu, Junfa; Xu, Lingyan; Xu, Yadong; Su, Jie; Zhang, Hao; Gu, Yaxu; Li, Jiawei; Ren, Jie; Zhao, Qinghua</p> <p>2016-01-28</p> <p>The interface <span class="hlt">layer</span> has great significance on the potential barrier <span class="hlt">height</span> of the CdTe/GaAs heterointerface. In this study, the electronic properties of the CdTe/GaAs heterostructure prepared by molecular beam epitaxy was investigated in situ by synchrotron radiation photoemission spectroscopy for CdTe thicknesses ranging from 3.5 to 74.6 Å. During CdTe deposition, an As-Te and Ga-Te interface reaction occurred, which caused the out diffusion of Ga. As a result a stable GaTe interface dipole <span class="hlt">layer</span> (more than 30 Å) was formed, which reduced the potential barrier <span class="hlt">height</span> by 0.38 eV. The potential barrier <span class="hlt">height</span> was in proportion to the chemical bonding density and thickness of the Ga-Te interface <span class="hlt">layer</span>. These results provide a more fundamental understanding of the influencing mechanism of the interface <span class="hlt">layer</span> on the potential barrier <span class="hlt">height</span> of the CdTe/GaAs heterointerface. PMID:26699197</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1813828A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1813828A"><span id="translatedtitle">Characterizing interactions between <span class="hlt">aerosols</span> and cloud droplets in marine boundary <span class="hlt">layer</span> clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Andersen, Hendrik; Cermak, Jan</p> <p>2016-04-01</p> <p>This contribution presents a method to characterize the nonlinearities of interactions between <span class="hlt">aerosols</span> and cloud droplets in marine boundary <span class="hlt">layer</span> clouds based on global MODIS observations. Clouds play a crucial role in the climate system as their radiative properties and precipitation patterns significantly impact the Earth's energy balance. Cloud properties are determined by environmental conditions, as cloud formation requires the availability of water vapour ("precipitable water") and condensation nuclei in sufficiently saturated conditions. The ways in which <span class="hlt">aerosols</span> as condensation nuclei in particular influence the optical, micro- and macrophysical properties of clouds are one of the largest remaining uncertainties in climate-change research. In particular, cloud droplet size is believed to be impacted, and thereby cloud reflectivity, lifetime, and precipitation susceptibility. However, the connection between <span class="hlt">aerosols</span> and cloud droplets is nonlinear, due to various factors and processes. The impact of <span class="hlt">aerosols</span> on cloud properties is thought to be strongest with low <span class="hlt">aerosol</span> loadings, whereas it saturates with high <span class="hlt">aerosol</span> loadings. To gain understanding of the processes that govern low cloud water properties in order to increase accuracy of climate models and predictions of future changes in the climate system is thus of great importance. In this study, global Terra MODIS L3 data sets are used to characterize the nonlinearities of the interactions between <span class="hlt">aerosols</span> and cloud droplets in marine boundary <span class="hlt">layer</span> clouds. MODIS observations are binned in classes of <span class="hlt">aerosol</span> loading to identify at what loading <span class="hlt">aerosol</span> impact on cloud droplets is the strongest and at which loading it saturates. Results are connected to ERA-Interim and MACC data sets to identify connections of detected patterns to meteorology and <span class="hlt">aerosol</span> species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.2201R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.2201R"><span id="translatedtitle">Sources and Transport of <span class="hlt">Aerosol</span> above the Boundary <span class="hlt">Layer</span> over the Mediterranean Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roberts, Greg; Corrigan, Craig; Ritchie, John; Pont, Veronique; Claeys, Marine; Sciare, Jean; Mallet, Marc; Dulac, François; Mihalopoulos, Nikos</p> <p>2015-04-01</p> <p>The Mediterranean Region has been identified as sensitive to changes in the hydrological cycle, which could affect the water resources for millions of people by the turn of the century. However, prior to recent observations, most climate models have not accounted for the impacts of <span class="hlt">aerosol</span> in this region. Past airborne studies have shown that <span class="hlt">aerosol</span> sources from Europe and Africa are often transported throughout the lower troposphere; yet, because of their complex vertical distribution, it is a challenge to capture the variability and quantify the contribution of these sources to the radiative budget and precipitation processes. The PAEROS ChArMEx Mountain Experiment (PACMEx) complemented the regional activities by collecting <span class="hlt">aerosol</span> data from atop a mountain on the island of Corsica, France in order to assess boundary <span class="hlt">layer</span> / free troposphere atmospheric processes. In June/July 2013, PACMEx instruments were deployed at 2000 m.asl near the center of Corsica, France to complement ground-based <span class="hlt">aerosol</span> observations at 550 m.asl on the northern peninsula, as well as airborne measurements. Comparisons between the peninsula site and the mountain site show similar general trends in <span class="hlt">aerosol</span> properties; yet, differences in <span class="hlt">aerosol</span> properties reveal the myriad transport mechanisms over the Mediterranean Basin. Using <span class="hlt">aerosol</span> physicochemical data coupled with back trajectory analysis, different sources have been identified including Saharan dust transport, residual dust mixed with sea salt, anthropogenic emissions from Western Europe, and a period of biomass burning from Eastern Europe. Each period exhibits distinct signatures in the <span class="hlt">aerosol</span> related to transport processes above and below the boundary <span class="hlt">layer</span>. In addition, the total <span class="hlt">aerosol</span> concentrations at the mountain site revealed a strong diurnal cycling the between the atmospheric boundary <span class="hlt">layer</span> and the free troposphere, which is typical of mountain-top observations. PACMEx was funded by the National Science Foundation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A31D3055R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A31D3055R&link_type=ABSTRACT"><span id="translatedtitle">Transport and Evolution of <span class="hlt">Aerosol</span> Above/Below the Boundary <span class="hlt">Layer</span> in the Western Mediterranean Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roberts, G. C.; Corrigan, C.; Ritchie, J.; Pont, V.; Claeys, M.; Sciare, J.; Mallet, M.; Dulac, F.</p> <p>2014-12-01</p> <p>The Mediterranean Region has been identified as sensitive to changes in the hydrological cycle, which could affect the water resources for millions of people by the turn of the century. However, prior to recent observations, most climate models have not accounted for the impacts of <span class="hlt">aerosol</span> in this region. Past airborne studies have shown that <span class="hlt">aerosol</span> sources from Europe and Africa are often transported throughout the lower troposphere; yet, because of their complex vertical distribution, it is a challenge to capture the variability and quantify the contribution of these sources to the radiative budget and precipitation processes. The PAEROS ChArMEx Mountain Experiment (PACMEx) complemented the regional activities of the ChArMEx/ADRIMED summer 2013 campaign by collecting <span class="hlt">aerosol</span> data from atop a mountain on the island of Corsica, France in order to assess boundary <span class="hlt">layer</span> / free troposphere atmospheric processes. In June/July 2013, PACMEx instruments were deployed at 2000 m.asl near the center of Corsica to complement ground-based <span class="hlt">aerosol</span> observations at 550 m.asl on the northern peninsula, as well as airborne measurements. Comparisons between the peninsula site and the mountain site show similar general trends in <span class="hlt">aerosol</span> properties; yet, differences in <span class="hlt">aerosol</span> properties reveal the myriad transport mechanisms over the Mediterranean Basin. Using <span class="hlt">aerosol</span> physicochemical data coupled with back trajectory analysis, different sources have been identified including Saharan dust transport, residual dust mixed with sea salt, anthropogenic emissions from Western Europe, and a period of biomass burning from Eastern Europe. Each period exhibits distinct signatures in the <span class="hlt">aerosol</span> related to transport processes above and below the boundary <span class="hlt">layer</span>. In addition, the total <span class="hlt">aerosol</span> concentrations at the mountain site revealed a strong diurnal cycling between the atmospheric boundary <span class="hlt">layer</span> and the free troposphere, which is typical of mountain-top observations. PACMEx was funded by the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997ApOpt..36.5168Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997ApOpt..36.5168Q"><span id="translatedtitle">Polarized light scattering by <span class="hlt">aerosols</span> in the marine atmospheric boundary <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quinby-Hunt, Mary S.; Erskine, Lael L.; Hunt, Arlon J.</p> <p>1997-07-01</p> <p>The intensity and polarization of light scattered from marine <span class="hlt">aerosols</span> affect visibility and contrast in the marine atmospheric boundary <span class="hlt">layer</span> (MABL). The polarization properties of scattered light in the MABL vary with size, refractive index, number distributions, and environmental conditions. Laboratory measurements were used to determine the characteristics and variability of the polarization of light scattered by <span class="hlt">aerosols</span> similar to those in the MABL. Scattering from laboratory-generated sea-salt-containing (SSC) NaCl, (NH 4 ) 2 SO 4 , and seawater components of marine <span class="hlt">aerosols</span> was measured with a scanning polarization-modulated nephelometer. Mie theory with Gaussian and log normal size distributions of spheres was used to calculate the polarized light scattering from various <span class="hlt">aerosol</span> composition models and from experimentally determined distributions of <span class="hlt">aerosols</span> in the marine boundary <span class="hlt">layer</span>. The modeling was verified by comparison with scattering from distilled water <span class="hlt">aerosols</span>. The study suggests that polarimetric techniques can be used to enhance techniques for improving visibility and remote imaging for various <span class="hlt">aerosol</span> types, Sun angles, and viewing conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A31G..07B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A31G..07B"><span id="translatedtitle">Response Timescales and Multiple Equilibria in Boundary-<span class="hlt">Layer</span> Cloud-<span class="hlt">Aerosol</span> Interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bretherton, C. S.; Berner, A.; Wood, R.</p> <p>2012-12-01</p> <p>Large-eddy simulations (LES) of subtropical stratocumulus-topped boundary <span class="hlt">layers</span> coupled to an interactive <span class="hlt">aerosol</span> model are run for multiday periods to examine their coupled equilibria and adjustment timescales. The LES includes two-moment Morrison microphysics, interactive radiation, and Razzak-Ghan cloud droplet activation from a single log-normal size distribution of hygroscopic <span class="hlt">aerosol</span> with prognosed total <span class="hlt">aerosol</span> mass and number. The <span class="hlt">aerosol</span> evolves due to surface and entrainment sources, dry coalescence, precipitation sinks coupled to the Morrison microphysics due to autoconversion and accretion of cloud droplets (and a source due to raindrop evaporation), and cloud and rain scavenging of interstitial <span class="hlt">aerosol</span>. Simulations are initialized with an idealized southeast Pacific stratocumulus sounding based on observations during VOCALS REx and forced with specified SST, mean subsidence, geostrophic wind, and free-tropospheric <span class="hlt">aerosol</span> concentration. The surface <span class="hlt">aerosol</span> source is based on the Clarke parameterization for the dependence of sea-salt number concentration on wind speed. Both surface and free-tropospheric <span class="hlt">aerosol</span> are assumed to quickly grow to a specified size due to a surface DMS source. The goal is to explore the adjustment timescales and long-term equilibria produced by this model, to compare with studies such as Wood et al. (2012) that postulate that remote marine boundary <span class="hlt">layer</span> <span class="hlt">aerosol</span> concentrations are controlled as much by the precipitation sink as the surface and entrainment sources. We show that the coupled cloud-<span class="hlt">aerosol</span> model supports rapid transitions from a solid, high <span class="hlt">aerosol</span>, stratocumulus-capped state to a cumulus-like state reminisniscent of pockets of open cells as the liquid water path rises above a threshold supporting sufficient precipitation. The system can support multiple long-term equilibria for the same boundary forcing, or slow oscillations between a collapsed POC-like state and a deepening, thickening stratocumulus</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A54E..06V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A54E..06V"><span id="translatedtitle">The Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">layer</span> through satellite and balloon-borne measurements combined with modelling approaches.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vernier, J. P.; Fairlie, T. D.; Natarajan, M.; Crawford, J. H.; Baker, N. C.; Wegner, T.; Deshler, T.; Gadhavi, H. S.; Kumar, S.; Singh, A. K.; Jayaraman, A.; Raj, A.; Alladi, H.; Ratnam, M. V.; Pandit, A.; Vignelles, D.; Wienhold, F.; Liu, H.; Kumar, S.</p> <p>2015-12-01</p> <p>The Asian tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> (ATAL) is a seasonal <span class="hlt">aerosol</span> feature occurring in the Upper Troposphere and Lower Stratosphere (UTLS) above Asia during the Summer Asian Monsoon. Vertically resolved <span class="hlt">aerosol</span> backscatter profiles from the Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder satellite Observation (CALIPSO) mission and extinction profiles from the Stratospheric <span class="hlt">Aerosol</span> and Gas Experiment (SAGE) have been used to infer the spatial and temporal distributions of the ATAL since the late 90's. We found that <span class="hlt">aerosol</span> optical thickness between 13-18km have increased by a factor of 2-3 over the past 16 years likely related to raising pollution levels in South East Asia occuring during the same period. Modelling studies of the ATAL using WACCAM 3 and GEOS-Chem have provided conflicting information on its origin and a better representation of in-cloud SO2 and <span class="hlt">aerosol</span> lifetime in GOES-Chem seems to be key to obtain consistent results with the few SO2 measurements available in the UTLS during the Asian Monsoon. In situ measurements of <span class="hlt">aerosol</span> and trace gases in the UTLS from several balloon campaigns which took place in summer 2014 and 2015 in Asia will be presented and discussed with combined satellite and modelling analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8770E..0YS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8770E..0YS"><span id="translatedtitle">Remote monitoring of <span class="hlt">aerosol</span> <span class="hlt">layers</span> over Sofia during Sahara dust transport episode (April, 2012)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stoyanov, Dimitar; Grigorov, Ivan; Deleva, Atanaska; Kolev, Nikolay; Peshev, Zahari; Kolarov, Georgi; Donev, Evgeni; Ivanov, Danko</p> <p>2013-03-01</p> <p>In this work we present results of lidar remote sensing of <span class="hlt">aerosol</span> <span class="hlt">layers</span> in the atmosphere above Sofia during an episode of Sahara dust transport, 02-07 April, 2012. The investigations were made using two lidar systems, one equipped with a CuBr-vapor laser, emitting at wavelength 510.6 nm, and a second one - with Nd:YAG laser, at wavelengths 1064 nm and 532 nm. The results of lidar measurements are presented in terms of vertical atmospheric backscatter coefficient profiles and color maps of the <span class="hlt">aerosol</span> stratification evolution. The involved into discussions ceilometer data (CHM 15k ceilometer) and satellite data from CALIPSO lidar, enhance the synergy of observations. Conclusion about atmospheric <span class="hlt">aerosol</span>'s origin was made upon analyses of the information of weather-forecast maps provided by the Forecast system of Barcelona Supercomputing Centre, which are accessible via Internet. Additional information was provided by calculations of the backward air mass trajectories, using online software of NOAA about HYSPLIT model. The comparison between the data from the two lidars and the ceilometer showed similar behavior of <span class="hlt">aerosol</span> <span class="hlt">layers</span> development in the atmosphere above Sofia. All information about <span class="hlt">aerosol</span> <span class="hlt">layers</span> origin, their altitude above ground, persistence during lidar observations, confirmed the conclusion of observation of a long-distance Sahara dust transport beyond Balkans and Sofia. An interesting completion of CALIPSO lidar and ground based lidars results of measurement is presented in case of thick opaque cloud <span class="hlt">layer</span> in the atmosphere, which slices the path of lidar sensing in both directions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EPJWC.11911002R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EPJWC.11911002R&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Aerosol</span>/Cloud Measurements Using Coherent Wind Doppler Lidars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Royer, Philippe; Boquet, Matthieu; Cariou, Jean-Pierre; Sauvage, Laurent; Parmentier, Rémy</p> <p>2016-06-01</p> <p>The accurate localization and characterization of <span class="hlt">aerosol</span> and cloud <span class="hlt">layers</span> is crucial for climate studies (<span class="hlt">aerosol</span> indirect effect), meteorology (Planetary Boundary <span class="hlt">Layer</span> PBL <span class="hlt">height</span>), site monitoring (industrial emissions, mining,…) and natural hazards (thunderstorms, volcanic eruptions). LEOSPHERE has recently developed <span class="hlt">aerosol</span>/cloud detection and characterization on WINDCUBE long range Coherent Wind Doppler Lidars (CWDL). These new features combine wind and backscatter intensity informations (Carrier-to-Noise Ratio CNR) in order to detect (<span class="hlt">aerosol</span>/cloud base and top, PBL <span class="hlt">height</span>) and to characterize atmospheric structures (attenuated backscatter, depolarization ratio). For each <span class="hlt">aerosol</span>/cloud functionality the method is described, limitations are discussed and examples are given to illustrate the performances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPSC...10..467S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPSC...10..467S"><span id="translatedtitle">Retrieving the <span class="hlt">aerosol</span> particle distribution in Titan's detached <span class="hlt">layer</span> from ISS limb observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seignovert, B.; Rannou, P.; Lavvas, P.; Cours, T.; West, R. A.</p> <p>2015-10-01</p> <p>The study of the detached haze <span class="hlt">layer</span> above Titan's thick atmosphere is one of the key elements to understand the growth of the <span class="hlt">aerosols</span> in the upper atmosphere of Titan. In this work we will present the results of a radiative transfer inversion of the vertical profile distribution of <span class="hlt">aerosols</span> in the detached haze <span class="hlt">layer</span> (from 300 to 600 km) by using the I/F ratio ob- served by Cassini ISS camera. The analyses will focus on the derivation of the particle size distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A33A3150G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A33A3150G"><span id="translatedtitle">Application and Limitations of GPS Radio Occultation (GPS-RO) Data for Atmospheric Boundary <span class="hlt">Layer</span> <span class="hlt">Height</span> Detection over the Arctic.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ganeshan, M.; Wu, D. L.</p> <p>2014-12-01</p> <p>Due to recent changes in the Arctic environment, it is important to monitor the atmospheric boundary <span class="hlt">layer</span> (ABL) properties over the Arctic Ocean, especially to explore the variability in ABL clouds (such as sensitivity and feedback to sea ice loss). For example, radiosonde and satellite observations of the Arctic ABL <span class="hlt">height</span> (and low-cloud cover) have recently suggested a positive response to sea ice loss during October that may not occur during the melt season (June-September). Owing to its high vertical and spatiotemporal resolution, an independent ABL <span class="hlt">height</span> detection algorithm using GPS Radio Occultation (GPS-RO) refractivity in the Arctic is explored. Similar GPS-RO algorithms developed previously typically define the level of the most negative moisture gradient as the ABL <span class="hlt">height</span>. This definition is favorable for subtropical oceans where a stratocumulus-topped ABL is often capped by a <span class="hlt">layer</span> of sharp moisture lapse rate (coincident with the temperature inversion). The Arctic Ocean is also characterized by stratocumulus cloud cover, however, the specific humidity does not frequently decrease in the ABL capping inversion. The use of GPS-RO refractivity for ABL <span class="hlt">height</span> retrieval therefore becomes more complex. During winter months (December-February), when the total precipitable water in the troposphere is a minimum, a fairly straightforward algorithm for ABL <span class="hlt">height</span> retrieval is developed. The applicability and limitations of this method for other seasons (Spring, Summer, Fall) is determined. The seasonal, interannual and spatial variability in the GPS-derived ABL <span class="hlt">height</span> over the Arctic Ocean, as well as its relation to the underlying surface (ice vs. water), is investigated. The GPS-RO profiles are also explored for the evidence of low-level moisture transport in the cold Arctic environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ThApC.109..577B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ThApC.109..577B"><span id="translatedtitle">Sensitivity of MM5-simulated planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> to soil dataset: comparison of soil and atmospheric effects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Breuer, Hajnalka; Ács, Ferenc; Laza, Borbála; Horváth, Ákos; Matyasovszky, István; Rajkai, Kálmán</p> <p>2012-08-01</p> <p>The effects of two soil datasets on planetary boundary <span class="hlt">layer</span> (PBL) <span class="hlt">height</span> are analyzed, using model simulations. Simulations are performed with the MM5 weather prediction system over the Carpathian Basin, with 6 km horizontal resolution, investigating three summer days, two autumn, and one winter day of similar synoptic conditions. Two soil datasets include that of the United States Department of Agriculture, which is globally used, and a regional Hungarian called Hungarian unsaturated soil database. It is shown that some hydraulic parameter values between the two datasets can differ up to 5-50%. These differences resulted in 10% deviations in the space-time-averaged PBL <span class="hlt">height</span> (averaged over Hungary and over 12 h in the daytime period). Over smaller areas, these relative deviations could reach 25%. Daytime course changes in the PBL <span class="hlt">height</span> for reference run conditions were significant ( p < 0.01) in ≈70% of the grid points covering Hungary. Ensemble runs using different atmospheric parameterizations and soil moisture initialization setups are also performed to analyze the sensitivity under changed conditions. In these cases, the sensitivity test showed that irrespective of the radiation and PBL scheme, the effect of different soil datasets on PBL <span class="hlt">height</span> is roughly the same. PBL <span class="hlt">height</span> is also sensitive to field capacity (Θf) and wilting point (Θw) changes. Θf changes seem to be more important for loamy sand, while Θw changes for the clay soil textural class.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20150023388&hterms=clouds&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dclouds','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20150023388&hterms=clouds&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dclouds"><span id="translatedtitle">Clouds, <span class="hlt">Aerosol</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span>: An ARM Mobile Facility Deployment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wood, Robert; Wyant, Matthew; Bretherton, Christopher S.; Remillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; de Szoeke, Simone; Yuter, Sandra; Miller, Matthew; Mechem, David; Tselioudis, George; Chiu, J. Christine; Mann, Julian A. L.; O'Connor, Ewan J.; Hogan, Robin J.; Dong, Xiquan; Miller, Mark; Ghate, Virendra; Jefferson, Anne; Min, Qilong; Minnis, Patrick; Palikonda, Rabindra; Albrecht, Bruce; Luke, Ed; Hannay, Cecile; Lin, Yanluan</p> <p>2015-01-01</p> <p>Capsule: A 21-month deployment to Graciosa Island in the northeastern Atlantic Ocean is providing an unprecedented record of the clouds, <span class="hlt">aerosols</span> and meteorology in a poorly-sampled remote marine environment The Clouds, <span class="hlt">Aerosol</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span> (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21 month (April 2009- December 2010) comprehensive dataset documenting clouds, <span class="hlt">aerosols</span> and precipitation using the Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, <span class="hlt">aerosols</span> and precipitation in the marine boundary <span class="hlt">layer</span>. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean, and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulus and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1- 11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of <span class="hlt">aerosol</span> conditions was sampled during the deployment consistent with the diversity of sources as indicated by back trajectory analysis. Preliminary findings suggest important two-way interactions between <span class="hlt">aerosols</span> and clouds at Graciosa, with <span class="hlt">aerosols</span> affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging. The data from at Graciosa are being compared with short-range forecasts made a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well, but the cloud-nucleating <span class="hlt">aerosol</span> concentrations less well. The Graciosa site has been chosen to be a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002JGRD..107.4053T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002JGRD..107.4053T&link_type=ABSTRACT"><span id="translatedtitle">New evidence of an organic <span class="hlt">layer</span> on marine <span class="hlt">aerosols</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tervahattu, Heikki; Hartonen, Kari; Kerminen, Veli-Matti; Kupiainen, Kaarle; Aarnio, Päivi; Koskentalo, Tarja; Tuck, Adrian F.; Vaida, Veronica</p> <p>2002-04-01</p> <p>An extraordinary episode of fine particles (diameter mainly <2.5 μm) occurred in Helsinki, southern Finland, at the end of February 1998. The air masses came from the North Atlantic Ocean and passed over France, Germany, and southern Scandinavia. Particles were collected during the episode as well as before and after it. Uncoated particle samples were adhered to an indium substrate and were studied by a scanning electron microscope (SEM) coupled with an energy dispersive X-ray microanalyzer (EDX). A great proportion of the particles behaved differently than <span class="hlt">aerosols</span> previously studied by microscopic techniques. The particles (size mainly 0.5-1 μm) did not exhibit solid shape. They were ``bubbling'' or ``pulsating'' continually, enlarging in one part and shrinking in another. Some particles were broken down, especially when the beam of the electron microscope was focused on them. EDX analyses showed that the particles contained much carbon together with oxygen, sulfur, and sodium. Ion analyses by ion chromatography revealed high concentrations of sodium, sulfate, nitrate, and ammonium. The particles were identified as marine sea-salt <span class="hlt">aerosols</span>, which had accumulated anthropogenic emissions and lost chloride during their flow through continental polluted air. The shape fluctuations and the high carbon content observed by SEM/EDX led to the conclusion that the <span class="hlt">aerosols</span> were enclosed by an organic membrane. Direct insertion probe/mass spectrometry investigations showed remarkable amounts of fragmented aliphatic hydrocarbons, which were considered as an evidence of a lipid membrane on the surface of the particles. The impact of the posited organic film on the properties of sea-salt particles, as well as on Earth's climate, is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22047369','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22047369"><span id="translatedtitle">DUAL ORIGIN OF <span class="hlt">AEROSOLS</span> IN TITAN'S DETACHED HAZE <span class="hlt">LAYER</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cours, T.; Burgalat, J.; Rannou, P.; Rodriguez, S.; Brahic, A.</p> <p>2011-11-10</p> <p>We have analyzed scattered light profiles from the Cassini Imaging Science Subsystem, taken at the limb and at several large phase angles. We also used results from an occultation observed by Ultraviolet Imaging Spectrograph in the ultraviolet. We found that particles responsible for the scattering in the detached haze have an effective radius around 0.15 {mu}m and the <span class="hlt">aerosol</span> size distribution follows a power law (exponent about -4.5). We discuss these results along with microphysical constraints and thermal equilibrium of the detached haze, and we conclude that only a strong interaction with atmospheric dynamics can explain such a structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1256713','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1256713"><span id="translatedtitle">Lidar Investigations of <span class="hlt">Aerosol</span>, Cloud, and Boundary <span class="hlt">Layer</span> Properties Over the ARM ACRF Sites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Turner, David D.; Ferrare, Richard</p> <p>2015-01-13</p> <p>The systematic and routine measurements of <span class="hlt">aerosol</span>, water vapor, and clouds in the vertical column above the Atmospheric Radiation Measurement (ARM) sites from surface-based remote sensing systems provides a unique and comprehensive data source that can be used to characterize the boundary <span class="hlt">layer</span> (i.e., the lowest 3 km of the atmosphere) and its evolution. New algorithms have been developed to provide critical datasets from ARM instruments, and these datasets have been used in long-term analyses to better understand the climatology of water vapor and <span class="hlt">aerosol</span> over Darwin, the turbulent structure of the boundary <span class="hlt">layer</span> and its statistical properties over Oklahoma, and to better determine the distribution of ice and <span class="hlt">aerosol</span> particles over northern Alaska.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AIPC.1100..392K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AIPC.1100..392K"><span id="translatedtitle">Initial assessment of space-based lidar CALIOP <span class="hlt">aerosol</span> and cloud <span class="hlt">layer</span> structures through inter-comparison with a ground-based back-scattering lidar and CloudSat</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, S.-W.; Yoon, S.-C.; Chung, E.-S.; Sohn, B.-J.; Berthier, S.; Raut, J.-C.; Chazette, P.; Dulac, F.</p> <p>2009-03-01</p> <p>This study presents results of the intercomparison of <span class="hlt">aerosol</span>/cloud top and bottom <span class="hlt">heights</span> obtained from a space-borne active sensor Cloud-<span class="hlt">Aerosol</span> Lidar with Orthogonal Polarization (CALIOP) onboard CALIPSO, and the Cloud Profiling Radar (CPR) onboard CloudSat, and the space-borne passive sensor Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Aqua, and ground-based 2-wavelenght polarization lidar system (532 and 1064 nm) at Seoul National University (SNU), Seoul, South Korea. This result confirms that the CALIPSO science team algorithms for the discrimination of cloud and <span class="hlt">aerosol</span> as well as for the detection of <span class="hlt">layer</span> top and base altitude provide reliable information both under cloud-free conditions and in cases of multiple <span class="hlt">aerosol</span> <span class="hlt">layers</span> underlying semi-transparent cirrus clouds. Simultaneous space-borne CALIOP, CPR and ground-based SNU lidar (SNU-L) measurements complement each other and can be combined to provide full information on the vertical distribution of <span class="hlt">aerosols</span> and clouds, especially for thick opaque clouds. The <span class="hlt">aerosol</span> extinction profiles from both lidars show good agreement for <span class="hlt">aerosols</span> within the planetary boundary <span class="hlt">layer</span> under cloud-free conditions and for the night-time CALIOP flight.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.7928K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.7928K"><span id="translatedtitle">Convective boundary <span class="hlt">layer</span> evolution from lidar backscatter and its relationship with surface <span class="hlt">aerosol</span> concentration at a location of a central China megacity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kong, Wei; Yi, Fan</p> <p>2015-08-01</p> <p>Based on the 1 min backscatter ratio R profiles from the all-day lidar measurements in Wuhan, China (30.5°N, 114.4°E), hourly convective boundary <span class="hlt">layer</span> (CBL) <span class="hlt">height</span> was calculated with the variance method. The calculated CBL <span class="hlt">height</span> sequence displays the regular diurnal cycle of the CBL top. The prevalent mixing process within the CBL is also revealed. During the CBL growth period, the backscatter ratio R falls visibly with increasing altitude and has large variance within the CBL, suggesting that more abundant <span class="hlt">aerosol</span> particles from lower altitudes are being transported upward and being mixed with the local background or advected <span class="hlt">aerosol</span> <span class="hlt">layers</span>. During the CBL quasistationary period, R tends to be vertically uniform, and its variance reaches a daytime minimum within the CBL, indicating that the vertical homogenization of <span class="hlt">aerosol</span> particles produced by the convectively driven mixing reaches its maximum. During the afternoon and early evening transition period, the vertical uniformity of R weakens and the variance enlarges again, implying that the reduced convectively driven mixing fails to maintain a high vertical homogeneity. When the 1 min R profiles were plotted together in terms of each 1 h interval, the fluctuating R curves at <span class="hlt">heights</span> around the CBL top looked like a "node", representing the structure of the entrainment zone between the CBL and the free troposphere. The moving node depicts the evolution of the entrainment zone. The diurnal variation of the CBL <span class="hlt">height</span> shows an obvious seasonal dependence which coincides with the annual variation of the local surface temperature. The surface fine particle concentration generally has a more complex diurnal cycle than that expected from the CBL-dilution/CBL-accumulation effect. But, it shows a strong annual variation which is out of phase with respect to that of the monthly mean maximum CBL <span class="hlt">height</span>. This tends to suggest that the seasonal behavior of the surface fine particle concentration mainly depends on the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8380E..0TF','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8380E..0TF"><span id="translatedtitle">Potential impacts of elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> on high energy laser aerial defense engagements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fiorino, Steven T.; Shirey, Stephen M.; Via, Michelle F.; Grahn, Daniel J.; Krizo, Matthew J.</p> <p>2012-06-01</p> <p>This study quantifies the impacts on high energy laser (HEL) air defense performance due to atmospheric effects in the marine boundary <span class="hlt">layer</span> driven by varying elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span>. The simulations are run using several different engagement geometries to more completely show the effects of <span class="hlt">aerosols</span>. High adaptive optics are applied to reduce the turbulence effects. The atmospheric effects are defined using the worldwide probabilistic climatic database available in the High Energy Laser End-to-End Operational Simulation (HELEEOS) model. The anticipated effects on HEL propagation performance is assessed at 1.0642 μm across the world's oceans, mapped on a 1° × 1° grid, and at 573 land sites. The scenarios evaluated are primarily near-surface and horizontal over ranges up to 10000 meters. Seasonal and boundary <span class="hlt">layer</span> variations (summer and winter) for a range of relative humidity percentile conditions are considered. In addition to realistic vertical profiles of molecular and <span class="hlt">aerosol</span> absorption and scattering, correlated optical turbulence profiles in probabilistic (percentile) format are used. Results indicate profound effects of elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> on HEL engagements as compared to standard scenarios without elevated <span class="hlt">layers</span>. Also, results suggest changing optical properties to have additional significant effects. HELEEOS includes a fast-calculating, first principles, worldwide surface to 100 km, atmospheric propagation and characterization package. This package enables the creation of profiles of temperature, pressure, water vapor content, optical turbulence, atmospheric particulates and hydrometeors as they relate to line-by-line <span class="hlt">layer</span> transmission, path and background radiance at wavelengths from the ultraviolet to radio frequencies. Physics-based cloud and precipitation characterizations are coupled with a probability of cloud free line of sight (CFLOS) algorithm for air-to-air, air-tosurface, and surface-to-air (or space) look angles. HELEEOS</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ACPD...15.9445R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ACPD...15.9445R&link_type=ABSTRACT"><span id="translatedtitle">Vertical profiling of <span class="hlt">aerosol</span> hygroscopic properties in the planetary boundary <span class="hlt">layer</span> during the PEGASOS campaigns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosati, B.; Gysel, M.; Rubach, F.; Mentel, T. F.; Goger, B.; Poulain, L.; Schlag, P.; Miettinen, P.; Pajunoja, A.; Virtanen, A.; Bialek, J.; Klein Baltink, H.; Henzing, J. S.; Größ, J.; Gobbi, G. P.; Wiedensohler, A.; Kiendler-Scharr, A.; O'Dowd, C.; Decesari, S.; Facchini, M. C.; Weingartner, E.; Baltensperger, U.</p> <p>2015-03-01</p> <p>Airborne measurements of the <span class="hlt">aerosol</span> hygroscopic and optical properties as well as chemical composition were performed in the Netherlands and northern Italy on board of a Zeppelin NT airship during the PEGASOS field campaigns in 2012. The vertical changes in <span class="hlt">aerosol</span> properties during the development of the mixing <span class="hlt">layer</span> were studied. Hygroscopic growth factors (GF) at 95% relative humidity were determined using the white-light humidified optical particles spectrometer (WHOPS) for dry diameters of 300 and 500 nm particles. These measurements were supplemented by an <span class="hlt">aerosol</span> mass spectrometer (AMS) and an aethalometer providing information on the <span class="hlt">aerosol</span> chemical composition. Several vertical profiles between 100 and 700 m a.g. were flown just after sunrise close to the San Pietro Capofiume ground station in the Po Valley, Italy. During the early morning hours the lowest <span class="hlt">layer</span> (newly developing mixing <span class="hlt">layer</span>) contained a high nitrate fraction (20%) which was coupled with enhanced hygroscopic growth. In the <span class="hlt">layer</span> above (residual <span class="hlt">layer</span>) small nitrate fractions of ~ 2% were measured as well as low GFs. After full mixing of the <span class="hlt">layers</span>, typically around noon and with increased temperature, the nitrate fraction decreased to 2% at all altitudes and led to similar hygroscopicity values as found in the residual <span class="hlt">layer</span>. These distinct vertical and temporal changes underline the importance of airborne campaigns to study <span class="hlt">aerosol</span> properties during the development of the mixed <span class="hlt">layer</span>. The <span class="hlt">aerosol</span> was externally mixed with 22 and 67% of the 500 nm particles in the range GF < 1.1 and GF > 1.5, respectively. Contributors to the non-hygroscopic mode in the observed size range are most likely mineral dust and biological material. Mean hygroscopicity parameters (κ) were 0.34, 0.19 and 0.18 for particles in the newly forming mixing <span class="hlt">layer</span>, residual <span class="hlt">layer</span> and fully mixed <span class="hlt">layer</span>, respectively. These results agree well with those from chemical analysis which found values of κ = 0.27, 0.21 and 0</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJWC.11923032Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJWC.11923032Z"><span id="translatedtitle"><span class="hlt">Aerosol</span> <span class="hlt">Layering</span> Characterization Near the Gobi Desert by a Double Polarization Lidar System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Y.; Boselli, A.; Sannino, A.; Song, C.; Spinelli, N.; Wang, X.</p> <p>2016-06-01</p> <p>In order to carry out 4-D (space and time) analysis of the atmospheric <span class="hlt">aerosol</span> distribution and to make a characterization of their properties and time evolution, a transportable multi-wavelength, Elastic/Raman scanning lidar system with angular scanning capability has been realized. The system uses a diode pumped Nd:YAG laser source, specifically designed for this device, and a receiving systems able to detect elastic signals at 355, 532 and 1064 nm and Raman signals at 386, 407 and 607 nm. It also allows to perform <span class="hlt">aerosol</span> depolarization measurements at both 355nm and 532nm. A first measurement campaign has been carried out in Dunhuang, North-West of China, in the region of the Gobi desert with the aims to study and characterize desert dust at source. Optical properties of <span class="hlt">aerosol</span> <span class="hlt">layers</span> developing in the atmosphere have been analyzed and lidar data are discussed in terms of profiles of <span class="hlt">aerosol</span> backscatter coefficient at 355nm, 532nm, <span class="hlt">aerosol</span> extinction coefficient at 355nm, <span class="hlt">aerosol</span> depolarization ratio at 355nm and 532nm and water vapor mixing ratio. Depolarization ratio measured simultaneously at two wavelengths allowed also to study its dependence on the wavelength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1255441','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1255441"><span id="translatedtitle">Clouds, <span class="hlt">Aerosols</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span>: An Arm Mobile Facility Deployment</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wood, Robert; Wyant, Matthew; Bretherton, Christopher S.; Rémillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; de Szoeke, Simone; Yuter, Sandra; Miller, Matthew; Mechem, David; Tselioudis, George; Chiu, J. Christine; Mann, Julian A. L.; O’Connor, Ewan J.; Hogan, Robin J.; Dong, Xiquan; Miller, Mark; Ghate, Virendra; Jefferson, Anne; Min, Qilong; Minnis, Patrick; Palikonda, Rabindra; Albrecht, Bruce; Luke, Ed; Hannay, Cecile; Lin, Yanluan</p> <p>2015-03-01</p> <p>The Clouds, <span class="hlt">Aerosol</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span> (CAP-MBL) 38 deployment at Graciosa Island in the Azores generated a 21 month (April 2009-December 2010) 39 comprehensive dataset documenting clouds, <span class="hlt">aerosols</span> and precipitation using the Atmospheric 40 Radiation Measurement (ARM) Mobile Facility (AMF). The scientific aim of the deployment is 41 to gain improved understanding of the interactions of clouds, <span class="hlt">aerosols</span> and precipitation in the 42 marine boundary <span class="hlt">layer</span>. 43 Graciosa Island straddles the boundary between the subtropics and midlatitudes in the 44 Northeast Atlantic Ocean, and consequently experiences a great diversity of meteorological and 45 cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulus and cumulus 46 occurring regularly. Approximately half of all clouds contained precipitation detectable as radar 47 echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-48 11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide 49 range of <span class="hlt">aerosol</span> conditions was sampled during the deployment consistent with the diversity of 50 sources as indicated by back trajectory analysis. Preliminary findings suggest important two-way 51 interactions between <span class="hlt">aerosols</span> and clouds at Graciosa, with <span class="hlt">aerosols</span> affecting light precipitation 52 and cloud radiative properties while being controlled in part by precipitation scavenging. 53 The data from at Graciosa are being compared with short-range forecasts made a variety 54 of models. A pilot analysis with two climate and two weather forecast models shows that they 55 reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well, 56 but the cloud-nucleating <span class="hlt">aerosol</span> concentrations less well. The Graciosa site has been chosen to 57 be a long-term ARM site that became operational in October 2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1201336-clouds-aerosol-precipitation-marine-boundary-layer-arm-mobile-facility-deployment','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1201336-clouds-aerosol-precipitation-marine-boundary-layer-arm-mobile-facility-deployment"><span id="translatedtitle">Clouds, <span class="hlt">aerosol</span>, and precipitation in the Marine Boundary <span class="hlt">Layer</span>: An ARM mobile facility deployment</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Wood, Robert; Luke, Ed; Wyant, Matthew; Bretherton, Christopher S.; Remillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; deSzoeke, S.; Yuter, Sandra; et al</p> <p>2014-04-27</p> <p>The Clouds, <span class="hlt">Aerosol</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span> (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21-month (April 2009-December 2010) comprehensive dataset documenting clouds, <span class="hlt">aerosols</span>, and precipitation using the Atmospheric Radiation Measurement Program (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, <span class="hlt">aerosols</span>, and precipitation in the marine boundary <span class="hlt">layer</span>. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulusmore » and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of <span class="hlt">aerosol</span> conditions was sampled during the deployment consistent with the diversity of sources as indicated by back-trajectory analysis. Preliminary findings suggest important two-way interactions between <span class="hlt">aerosols</span> and clouds at Graciosa, with <span class="hlt">aerosols</span> affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging.The data from Graciosa are being compared with short-range forecasts made with a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well but the cloud-nucleating <span class="hlt">aerosol</span> concentrations less well. The Graciosa site has been chosen to be a permanent fixed ARM site that became operational in October 2013.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1201336','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1201336"><span id="translatedtitle">Clouds, <span class="hlt">aerosol</span>, and precipitation in the Marine Boundary <span class="hlt">Layer</span>: An ARM mobile facility deployment</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wood, Robert; Luke, Ed; Wyant, Matthew; Bretherton, Christopher S.; Remillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; deSzoeke, S.; Yuter, Sandra; Miller, Matthew; Mechem, David; Tselioudis, George; Chiu, Christine; Mann, Julia; O Connor, Ewan; Hogan, Robin; Dong, Xiquan; Miller, Mark; Ghate, Virendra; Jefferson, Anne; Min, Qilong; Minnis, Patrick; Palinkonda, Rabindra; Albrecht, Bruce; Hannay, Cecile; Lin, Yanluan</p> <p>2014-04-27</p> <p>The Clouds, <span class="hlt">Aerosol</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span> (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21-month (April 2009-December 2010) comprehensive dataset documenting clouds, <span class="hlt">aerosols</span>, and precipitation using the Atmospheric Radiation Measurement Program (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, <span class="hlt">aerosols</span>, and precipitation in the marine boundary <span class="hlt">layer</span>. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulus and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of <span class="hlt">aerosol</span> conditions was sampled during the deployment consistent with the diversity of sources as indicated by back-trajectory analysis. Preliminary findings suggest important two-way interactions between <span class="hlt">aerosols</span> and clouds at Graciosa, with <span class="hlt">aerosols</span> affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging.The data from Graciosa are being compared with short-range forecasts made with a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well but the cloud-nucleating <span class="hlt">aerosol</span> concentrations less well. The Graciosa site has been chosen to be a permanent fixed ARM site that became operational in October 2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100021131','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100021131"><span id="translatedtitle">LASE Measurements of Water Vapor, <span class="hlt">Aerosol</span>, and Cloud Distributions in Saharan Air <span class="hlt">Layers</span> and Tropical Disturbances</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ismail, Syed; Ferrare, Richard A.; Browell, Edward V.; Kooi, Susan A.; Dunion, Jason P.; Heymsfield, Gerry; Notari, Anthony; Butler, Carolyn F.; Burton, Sharon; Fenn, Marta; Krishnamurti, T. N.; Chen, Gao; Anderson, Bruce</p> <p>2010-01-01</p> <p>LASE (Lidar Atmospheric Sensing Experiment) on-board the NASA DC-8 measured high resolution profiles of water vapor and <span class="hlt">aerosols</span>, and cloud distributions in 14 flights over the eastern North Atlantic during the NAMMA (NASA African Monsoon Multidisciplinary Analyses) field experiment. These measurements were used to study African easterly waves (AEWs), tropical cyclones (TCs), and the Saharan Air <span class="hlt">Layer(s</span>) (SAL). Interactions between the SAL and tropical air were observed during the early stages of the TC development. These LASE measurements represent the first simultaneous water vapor and <span class="hlt">aerosol</span> lidar measurements to study the SAL and its impact on AEWs and TCs. Examples of profile measurements of <span class="hlt">aerosol</span> scattering ratios, <span class="hlt">aerosol</span> extinction coefficients, <span class="hlt">aerosol</span> optical thickness, water vapor mixing ratios, RH, and temperature are presented to illustrate their characteristics in SAL, convection, and clear air regions. LASE data suggest that the SAL suppresses low-altitude convection at the convection-SAL interface region. Mid-level convection associated with the AEW and transport are likely responsible for high water vapor content observed in the southern regions of the SAL on August 20, 2008. This interaction is responsible for the transfer of about 7 x 10(exp 15) J latent heat energy within a day to the SAL. Measurements of lidar extinction-to-backscatter ratios in the range 36+/-5 to 45+/-5 are within the range of measurements from other lidar measurements of dust. LASE <span class="hlt">aerosol</span> extinction and water vapor profiles are validated by comparison with onboard in situ <span class="hlt">aerosol</span> measurements and GPS dropsonde water vapor soundings, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121...49D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121...49D&link_type=ABSTRACT"><span id="translatedtitle">Mixed-<span class="hlt">layer</span> ocean responses to anthropogenic <span class="hlt">aerosol</span> dimming from 1870 to 2000</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dallafior, T. N.; Folini, D.; Knutti, R.; Wild, M.</p> <p>2016-01-01</p> <p>It is debated to what extent surface solar radiation (SSR) changes through varying anthropogenic <span class="hlt">aerosol</span> emissions since industrialization affected surface temperatures (tsurf). We use mixed-<span class="hlt">layer</span> ocean experiments with the general circulation model ECHAM6.1 and explicit <span class="hlt">aerosols</span> (HAM2.2) to identify regions where this effect is discernible. For each decade from 1870 to 2000 we derive three equilibria: anthropogenic <span class="hlt">aerosol</span> emissions and greenhouse gas concentrations at the respective decade's levels (ALL), either <span class="hlt">aerosols</span> or greenhouse gases fixed at year 1850 levels (GHG and AERO). We duplicated parts of the experiments with different prescribed divergence of ocean heat transport (Q_ALL, Q_AERO, and Q_GHG). Comparing year 2000 with year 1870 equilibria, we find global average cooling of -1.4 K for AERO and warming of 1.4 K for GHG. ALL and Q_ALL warm by 0.6 K and 0.4 K, respectively. The way divergence of ocean heat transport is prescribed thus matters. Pattern correlations of year 2000 tsurf responses in ALL with the sum of AERO and GHG are higher (0.88) than with Q_ALL (0.71) confirming additivity of global patterns, but not of global means. The imprint of anthropogenic <span class="hlt">aerosols</span> on tsurf response patterns in ALL is distinct, thus potentially detectable. Over the decades, ocean fractions affected by either changing <span class="hlt">aerosol</span> optical depth or all-sky SSR vary in concert, supporting linkage between anthropogenic <span class="hlt">aerosols</span> and all-sky SSR. SSR changes and tsurf responses are marginally collocated. Oceanic regions with strongest tsurf response to <span class="hlt">aerosol</span>-induced SSR changes are the northern midlatitudes and North Pacific with tsurf sensitivities up to -0.7 K W m-2 SSR change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1815617D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1815617D&link_type=ABSTRACT"><span id="translatedtitle">Mixed-<span class="hlt">layer</span> ocean responses to anthropogenic <span class="hlt">aerosol</span> dimming from 1870 to 2000</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dallafior, Tanja; Folini, Doris; Knutti, Reto; Wild, Martin</p> <p>2016-04-01</p> <p>It is still debated, to what extent anthropogenic <span class="hlt">aerosol</span>-induced changes in surface solar radiation (SSR) since industrialization affected surface temperatures (tsurf). We use mixed-<span class="hlt">layer</span> ocean (MLO) experiments with the general circulation model ECHAM6.1 and explicit <span class="hlt">aerosols</span> (HAM2.2) to identify regions where this effect is discernible. For each decade from 1870 to 2000 we derive three equilibria: anthropogenic <span class="hlt">aerosol</span> emissions and greenhouse gas concentrations at the respective decade's levels (ALL), either <span class="hlt">aerosols</span> or greenhouse gases fixed at year 1850 levels (GHG and AERO). We duplicated parts of the experiments with different prescribed divergence of ocean heat transport (Q_ALL, Q_AERO, Q_GHG). Comparing year 2000 with year 1870 equilibria, we find global average cooling of -1.4K for AERO, and warming of 1.4K for GHG. ALL and Q_ALL warm by 0.6K and 0.4K, respectively. The way divergence of ocean heat transport is prescribed thus matters. Pattern correlations of year 2000 tsurf responses in ALL with the sum of AERO and GHG are higher (0.88) than with Q_ALL (0.71) confirming additivity of global patterns, but not of global means. The imprint of anthropogenic <span class="hlt">aerosols</span> on tsurf response patterns in ALL is distinct, thus potentially detectable. Over the decades, ocean fractions affected by either changing <span class="hlt">aerosol</span> optical depth or all-sky SSR vary in concert, supporting linkage between anthropogenic <span class="hlt">aerosols</span> and all-sky SSR. SSR changes and tsurf responses are marginally collocated. Oceanic regions with strongest tsurf response to <span class="hlt">aerosol</span>-induced SSR changes are the northern mid-latitudes and North Pacific with tsurf sensitivities up to -0.7K per Wm-2 SSR change. Results presented have been published under the same title in the Journal of Geophysical Research, Volume 121, DOI 10.1002/2015JD024070.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5974A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5974A&link_type=ABSTRACT"><span id="translatedtitle">Surface ozone-<span class="hlt">aerosol</span> behaviour and atmospheric boundary <span class="hlt">layer</span> structure in Saharan dusty scenario</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adame, Jose; Córdoba-Jabonero, Carmen; Sorrribas, Mar; Gil-Ojeda, Manuel; Toledo, Daniel; Yela, Margarita</p> <p>2016-04-01</p> <p>A research campaign was performed for the AMISOC (Atmospheric Minor Species relevant to the Ozone Chemistry) project at El Arenosillo observatory (southwest Spain) in May-June 2012. The campaign focused on the impact of Saharan dust intrusions at the Atmospheric Boundary <span class="hlt">Layer</span> (ABL) and ozone-<span class="hlt">aerosol</span> interactions. In-situ and remote-sensing techniques for gases and <span class="hlt">aerosols</span> were used moreover to modelling analyses. Meteorology features, ABL structures and evolution, <span class="hlt">aerosol</span> profiling distributions and <span class="hlt">aerosol</span>-ozone interactions on the surface were analysed. Two four-day periods were selected according to non-dusty (clean conditions) and dusty (Saharan dust) situations. In both scenarios, sea-land breezes developed in the lower atmosphere, but differences were found in the upper levels. Results show that surface temperatures were greater than 3°C and humidity values were lower during dusty conditions than non-dusty conditions. Thermal structures on the surface <span class="hlt">layer</span> (estimated using an instrument on a 100 m tower) show differences, mainly during nocturnal periods with less intense inversions under dusty conditions. The mixing <span class="hlt">layer</span> during dusty days was 400-800 m thick, less than observed on non-dusty days. Dust also disturbed the typical daily ABL evolution. Stable conditions were observed during the early evening during intrusions. <span class="hlt">Aerosol</span> extinction on dusty days was 2-3 times higher, and the dust was confined between 1500 and 5500 m. Back trajectory analyses confirmed that the dust had an African origin. On the surface, the particle concentration was approximately 3.5 times higher during dusty events, but the local ozone did not exhibit any change. The arrival of Saharan dust in the upper levels impacted the meteorological surface, inhibited the daily evolution of the ABL and caused an increase in <span class="hlt">aerosol</span> loading on the surface and at higher altitudes; however, no dust influence was observed on surface ozone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SpWea..13..211J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SpWea..13..211J"><span id="translatedtitle">Investigation on F <span class="hlt">layer</span> <span class="hlt">height</span> rise and equatorial spread F onset time: Signature of standing large-scale wave</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Joshi, Lalit Mohan; Balwada, S.; Pant, T. K.; Sumod, S. G.</p> <p>2015-04-01</p> <p>Equatorial spread F observations have been categorized into three categories based on ionograms recorded over Sriharikota. First category comprised cases where the onset of equatorial spread F (ESF) was concurrent with the peak h'F time. Second and third categories comprised cases where the onset of ESF happened with a delay of 30 min and more than 30 min, respectively, with reference to the peak h'F time. Average peak h'F in the first category was more than 35 km higher than that in the second and third categories. Also, the peak vertical (upward) plasma drift was higher in the first category. Assuming the genesis of F region irregularity to have happened at or before the time of F <span class="hlt">layer</span> attaining the peak <span class="hlt">height</span>, late onset of ESF indicates the genesis of irregularities to have happened westward of Sriharikota. The fact that the peak h'F values were remarkably different in the three categories indicates a zonal variation of eastward electric field and postsunset <span class="hlt">height</span> rise of F <span class="hlt">layer</span>. The relative magnitude of the F <span class="hlt">layer</span> <span class="hlt">height</span> rise in the three different categories over Sriharikota has also been found to be significantly different than that over Thumba, an equatorial (magnetic) station located ~360 km westward of Sriharikota longitude. This scenario points toward the existence of a large-scale zonal standing wave in the F <span class="hlt">layer</span> and its important role in F region instability process. Results presented in the manuscript have been discussed in the light of current understanding on the large-scale wave structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.7295R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.7295R&link_type=ABSTRACT"><span id="translatedtitle">Vertical profiling of <span class="hlt">aerosol</span> hygroscopic properties in the planetary boundary <span class="hlt">layer</span> during the PEGASOS campaigns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosati, Bernadette; Gysel, Martin; Rubach, Florian; Mentel, Thomas F.; Goger, Brigitta; Poulain, Laurent; Schlag, Patrick; Miettinen, Pasi; Pajunoja, Aki; Virtanen, Annele; Klein Baltink, Henk; Bas Henzing, J. S.; Größ, Johannes; Gobbi, Gian Paolo; Wiedensohler, Alfred; Kiendler-Scharr, Astrid; Decesari, Stefano; Facchini, Maria Cristina; Weingartner, Ernest; Baltensperger, Urs</p> <p>2016-06-01</p> <p>Vertical profiles of the <span class="hlt">aerosol</span> particles hygroscopic properties, their mixing state as well as chemical composition were measured above northern Italy and the Netherlands. An <span class="hlt">aerosol</span> mass spectrometer (AMS; for chemical composition) and a white-light humidified optical particle spectrometer (WHOPS; for hygroscopic growth) were deployed on a Zeppelin NT airship within the PEGASOS project. This allowed one to investigate the development of the different <span class="hlt">layers</span> within the planetary boundary <span class="hlt">layer</span> (PBL), providing a unique in situ data set for airborne <span class="hlt">aerosol</span> particles properties in the first kilometre of the atmosphere. Profiles measured during the morning hours on 20 June 2012 in the Po Valley, Italy, showed an increased nitrate fraction at ˜ 100 m above ground level (a.g.l.) coupled with enhanced hygroscopic growth compared to ˜ 700 m a. g. l. This result was derived from both measurements of the <span class="hlt">aerosol</span> composition and direct measurements of the hygroscopicity, yielding hygroscopicity parameters (κ) of 0.34 ± 0.12 and 0.19 ± 0.07 for 500 nm particles, at ˜ 100 and ˜ 700 m a. g. l., respectively. The difference is attributed to the structure of the PBL at this time of day which featured several independent sub-<span class="hlt">layers</span> with different types of <span class="hlt">aerosols</span>. Later in the day the vertical structures disappeared due to the mixing of the <span class="hlt">layers</span> and similar <span class="hlt">aerosol</span> particle properties were found at all probed altitudes (mean κ ≈ 0.18 ± 0.07). The <span class="hlt">aerosol</span> properties observed at the lowest flight level (100 m a. g. l.) were consistent with parallel measurements at a ground site, both in the morning and afternoon. Overall, the <span class="hlt">aerosol</span> particles were found to be externally mixed, with a prevailing hygroscopic fraction. The flights near Cabauw in the Netherlands in the fully mixed PBL did not feature altitude-dependent characteristics. Particles were also externally mixed and had an even larger hygroscopic fraction compared to the results in Italy. The mean κ from</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090020627','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090020627"><span id="translatedtitle">Estimating Mixing <span class="hlt">Heights</span> Using Microwave Temperature Profiler</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nielson-Gammon, John; Powell, Christina; Mahoney, Michael; Angevine, Wayne</p> <p>2008-01-01</p> <p>A paper describes the Microwave Temperature Profiler (MTP) for making measurements of the planetary boundary <span class="hlt">layer</span> thermal structure data necessary for air quality forecasting as the Mixing <span class="hlt">Layer</span> (ML) <span class="hlt">height</span> determines the volume in which daytime pollution is primarily concentrated. This is the first time that an airborne temperature profiler has been used to measure the mixing <span class="hlt">layer</span> <span class="hlt">height</span>. Normally, this is done using a radar wind profiler, which is both noisy and large. The MTP was deployed during the Texas 2000 Air Quality Study (TexAQS-2000). An objective technique was developed and tested for estimating the ML <span class="hlt">height</span> from the MTP vertical temperature profiles. In order to calibrate the technique and evaluate the usefulness of this approach, estimates from a variety of measurements during the TexAQS-2000 were compared. Estimates of ML <span class="hlt">height</span> were used from radiosondes, radar wind profilers, an <span class="hlt">aerosol</span> backscatter lidar, and in-situ aircraft measurements in addition to those from the MTP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006SPIE.6522E..1BK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006SPIE.6522E..1BK"><span id="translatedtitle">Development of the code MaexPro for calculation atmospheric <span class="hlt">aerosol</span> extinction in the marine and coastal surface <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaloshin, Gennady A.; Shishkin, Sergey A.; Serov, Sergey A.</p> <p>2006-11-01</p> <p>In the paper the description of the last version of the code MaexPro (Marine <span class="hlt">aerosol</span> extinction Profile) for calculation spectral and vertical profiles of <span class="hlt">aerosol</span> extinction coefficient α( λ), <span class="hlt">aerosol</span> sizes distribution, area distribution, volumes distribution, modes <span class="hlt">aerosol</span> extinction spectra using standard meteorological parameters, <span class="hlt">aerosol</span> microphysical structure, a spectral band and a <span class="hlt">height</span> of the sensor location place is submitted. The code MaexPro is the computer program under constantly development to estimate of EO systems signal power at a location place in which a fetch is key entrance parameter. Spectral behavior α( λ) can be submitted as graphically, and as tables. Commands overplot for superposition or change of figures; profiles extrapolation; a lens; all kinds of possible copying; the data presentation, convenient for an input in code MODTRAN, and etc. are stipulated. The code MaexPro is a completely mouse-driven PC Windows program with a user-friendly interface. Calculation time of spectral and vertical profiles of α( λ) depends on the necessary wave length resolution, radius of <span class="hlt">aerosol</span> particles and the location place <span class="hlt">height</span>, and does not exceed tens seconds for each new meteorological condition. Other calculations characteristics, such as <span class="hlt">aerosol</span> sizes distribution, area distribution, volumes distribution, modes <span class="hlt">aerosol</span> extinction spectra, are performed in a few seconds.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFM.A21B0066L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFM.A21B0066L&link_type=ABSTRACT"><span id="translatedtitle">Comparison of Atmospheric Column Optical Depth Measurements for Urban Reno, NV with Three Different Sun Photometers and In Situ Measurements Combined with Boundary <span class="hlt">Layer</span> <span class="hlt">Height</span> Estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Loria Salazar, S. M.; Arnott, W. P.; Moosmuller, H.; Sumlin, B.; Karr, D.</p> <p>2011-12-01</p> <p>Reno, Nevada, USA is located in a mountain valley often characterized by very dry conditions, clear sky and red sunsets during the summer season, with rare incursions of monsoonal moisture. This city is subject to moderately strong nocturnal inversions nearly every day in summer. Urban <span class="hlt">aerosols</span>, wind blown dust, as well as occasional biomass burning smoke from natural and non-natural fires all contribute to the optical depth. Because of its geographical position, drastic changes in weather conditions and variations in <span class="hlt">aerosol</span> optical properties make Reno an excellent location for evaluating measurements of <span class="hlt">aerosol</span> optical depth in order to determine particulate air pollution concentration as well as to provide input for models of atmospheric radiation transfer and evaluation of satellite-based <span class="hlt">aerosol</span> optical sensing measurements. <span class="hlt">Aerosol</span> optical depth can be calculated by in situ photoacoustic measurements of <span class="hlt">aerosol</span> light absorption and reciprocal nephelometer scattering coefficients and estimation of <span class="hlt">aerosol</span> mixing <span class="hlt">height</span>. LED-based hand-held sun photometers are commonly used as inexpensive instruments for informal networks. However, the LED emission wavelength maximum and bandwidth are higher and narrower than the LED reception wavelength spectrum, necessitating empirical determination of an equivalent wavelength. The manually operated spectrometer and Cimel sun photometer measurements provide the most accurate and precise column <span class="hlt">aerosol</span> optical depth. This paper makes a comparison between these four instruments for measurements obtained during the summer and fall seasons in order to study how the total and <span class="hlt">aerosol</span> optical depth change during dry and moist conditions. Ångström exponents of extinction and absorption are also analyzed to provide insight on <span class="hlt">aerosol</span> size distribution and composition, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ESSD....7..311L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ESSD....7..311L"><span id="translatedtitle">CO2-flux measurements above the Baltic Sea at two <span class="hlt">heights</span>: flux gradients in the surface <span class="hlt">layer</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lammert, A.; Ament, F.</p> <p>2015-11-01</p> <p>The estimation of CO2 exchange between the ocean and the atmosphere is essential to understand the global carbon cycle. The eddy-covariance technique offers a very direct approach to observe these fluxes. The turbulent CO2 flux is measured, as well as the sensible and latent heat flux and the momentum flux, a few meters above the ocean in the atmosphere. Assuming a constant-flux <span class="hlt">layer</span> in the near-surface part of the atmospheric boundary <span class="hlt">layer</span>, this flux equals the exchange flux between ocean and atmosphere. The purpose of this paper is the comparison of long-term flux measurements at two different <span class="hlt">heights</span> above the Baltic Sea to investigate this assumption. The results are based on a 1.5-year record of quality-controlled eddy-covariance measurements. Concerning the flux of momentum and of sensible and latent heat, the constant-flux <span class="hlt">layer</span> theory can be confirmed because flux differences between the two <span class="hlt">heights</span> are insignificantly small more than 95 % of the time. In contrast, significant differences, which are larger than the measurement error, occur in the CO2 flux about 35 % of the time. Data used for this paper are published at <a href="http://doi.pangaea.de/10.1594/PANGAEA.808714" target="_blank">http://doi.pangaea.de/10.1594/PANGAEA.808714</a>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20010092168&hterms=marine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmarine','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20010092168&hterms=marine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmarine"><span id="translatedtitle">Airborne Sunphotometry of African Dust and Marine Boundary <span class="hlt">Layer</span> <span class="hlt">Aerosols</span> in PRIDE</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Livingston, John M.; Redemann, Jens; Russell, Philip; Schmid, Beat; Reid, Jeff; Pilewskie, Peter; Hipskind, R. Stephen (Technical Monitor)</p> <p>2000-01-01</p> <p>The Puerto Rico Dust Experiment (PRIDE) was conducted during summer 2000 to study the radiative, microphysical and transport properties of Saharan dust in the Caribbean region. During PRIDE, NASA Ames Research Center's six-channel airborne autotracking sunphotometer (AATS-6) was operated aboard a Piper Navajo airplane based at Roosevelt Roads Naval Station on the northeast coast of Puerto Rico. AATS-6 measurements were taken during 21 science flights off the coast of Puerto Rico in the western Caribbean. Data were acquired within and above the Marine Boundary <span class="hlt">Layer</span> (MBL) and the Saharan <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> (SAL) up to 5.5 km altitude tinder a wide range of dust loadings. <span class="hlt">Aerosol</span> optical depth (AOD) spectra and columnar water vapor (CWV) values have been calculated from the AATS-6 measurements by using sunphotometer calibration data obtained at Mauna Loa Observatory (3A kin ASL) before (May) and after (October) PRIDE. Mid-visible AOD values measured near the surface during PRIDE ranged from 0.07 on the cleanest day to 0.55 on the most turbid day. Values measured above the MBL were as high as 0.35; values above the SAL were as low as 0.01. The fraction of total column AOD due to Saharan dust cannot be determined precisely from AATS-6 AOD data alone due to the uncertainty in the extent of vertical mixing of the dust down through the MBL. However, analyses of ground-based and airborne in-situ <span class="hlt">aerosol</span> sampling measurements and ground-based <span class="hlt">aerosol</span> lidar backscatter data should yield accurate characterization of the vertical mixing that will enable calculation of the Saharan dust AOD component from the sunphotometer data. Examples will be presented showing measured AATS-6 AOD spectra, calculated <span class="hlt">aerosol</span> extinction and water vapor density vertical profiles, and <span class="hlt">aerosol</span> size distributions retrieved by inversion of the AOD spectra. Near sea-surface AOD spectra acquired by AATS-6 during horizontal flight legs at 30 m ASL are available for validation of AOD derived from coincident</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6877495','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6877495"><span id="translatedtitle">Measurement of the <span class="hlt">height</span> of the solar CO <span class="hlt">layer</span> during the 11 July 1991 eclipse</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Clark, T.A.; Naylor, D.A.; Tompkins, G.J.; Lindsey, C.A.; Jefferies, J.T.; Becklin, E.E. ); Roellig, T.L.; Harrison, R.A.; Carter, M.; Braun, D.C.; Watt, G.</p> <p>1992-01-01</p> <p>Normal' chromospheric indicators such as CaII H K, MgII h k, HI Ly[alpha] and the UV and far IR continua all show the presence in the solar atmosphere of a distinct temperature inversion with a minimum temperature of about 4300 K at 550 km above the photosphere and a temperature rise in the lower chromosphere. In distinct contrast, the characteristics of lines in the V-R bands of CO show the presence of cool plasma extending over this <span class="hlt">height</span> range, with T < 3800 K. Present models suggest that the CO exists only in clouds of limited vertical extent above supergranular cells, surrounded by a hotter chromospheric network containing embedded magnetic flux tubes. One remaining uncertainty is the <span class="hlt">height</span> and vertical extent of these CO clouds. Near IR total eclipse observations from Mauna Kea on 11 July 1991 have provided a measure of the limb extension of CO emission in the fundamental V-R band between 4.4 5.4 [mu]m compared to both the IR continuum and visible limbs. The CO limb' is found to be 125 +/- -15 km above this visible limb, or 465 km above [tau][sub 0.5] = 1, which places the main CO concentration just below the temperature minimum but above the [tau][sub CO] = 1 level of 430 km in the semi-empirical hot chromosphere' model of Avrett but below the equivalent level of 560 km in the cool' radiative equilibrium model of Anderson.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRD..11213205N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRD..11213205N"><span id="translatedtitle">Wintertime <span class="hlt">aerosol</span> characteristics over the Indo-Gangetic Plain (IGP): Impacts of local boundary <span class="hlt">layer</span> processes and long-range transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nair, Vijayakumar S.; Moorthy, K. Krishna; Alappattu, Denny P.; Kunhikrishnan, P. K.; George, Susan; Nair, Prabha R.; Babu, S. Suresh; Abish, B.; Satheesh, S. K.; Tripathi, Sachchida Nand; Niranjan, K.; Madhavan, B. L.; Srikant, V.; Dutt, C. B. S.; Badarinath, K. V. S.; Reddy, R. Ramakrishna</p> <p>2007-07-01</p> <p>The Indo-Gangetic Plain (IGP) encompasses a vast area, (accounting for ˜21% of the land area of India), which is densely populated (accommodating ˜40% of the Indian population). Highly growing economy and population over this region results in a wide range of anthropogenic activities. A large number of thermal power plants (most of them coal fed) are clustered along this region. Despite its importance, detailed investigation of <span class="hlt">aerosols</span> over this region is sparse. During an intense field campaign of winter 2004, extensive <span class="hlt">aerosol</span> and atmospheric boundary <span class="hlt">layer</span> measurements were made from three locations: Kharagpur (KGP), Allahabad (ALB), and Kanpur (KNP), within the IGP. These data are used (1) to understand the regional features of <span class="hlt">aerosols</span> and BC over the IGP and their interdependencies, (2) to compare it with features at locations lying at far away from the IGP where the conditions are totally different, (3) to delineate the effects of mesoscale processes associated with changes in the local atmospheric boundary <span class="hlt">layer</span> (ABL), (4) to investigate the effects of long-range transport or moving weather phenomena in modulating the <span class="hlt">aerosol</span> properties as well as the ABL characteristics, and (5) to examine the changes as the season changes over to spring and summer. Our investigations have revealed very high concentrations of <span class="hlt">aerosols</span> along the IGP, the average mass concentrations (MT) of total <span class="hlt">aerosols</span> being in the range 260 to 300 μg m-3 and BC mass concentrations (MB) in the range 20 to 30 μg m-3 (both ˜5 to 8 times higher than the values observed at off-IGP stations) during December 2004. Despite, BC constituted about 10% to the total <span class="hlt">aerosol</span> mass concentration, a value quite comparable to those observed elsewhere over India for this season. The dynamics of the local atmospheric boundary <span class="hlt">layer</span> (ABL) as well as changes in local emissions strongly influence the diurnal variations of MT and MB, both being inversely correlated with the mixed <span class="hlt">layer</span> <span class="hlt">height</span> (Zi) and the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1213512U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1213512U"><span id="translatedtitle">Radiosonde <span class="hlt">aerosol</span> counter for vertical profiling of atmospheric dust <span class="hlt">layers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ulanowski, Z.; Hirst, E.; Kaye, P. H.; Harrison, R. G.; Nicoll, K. A.; Rogers, G.</p> <p>2010-05-01</p> <p>A low-cost, miniature <span class="hlt">aerosol</span> particle counter has been developed, intended for use with balloon-borne meteorological radiosondes. It is particularly suitable for airborne mineral dust measurements. Ambient air is drawn into the counter using a diaphragm pump at a rate of 0.5 litre per minute. The counter detects particles in the airstream using a diode laser and a photodiode. Output from the photodiode is digitised into 5 size bins, with minimum particle diameters equivalent to 0.6, 1.4, 2.6, 5.4 and 10.6 micrometers. The counter is interfaced to a Vaisala RS92 radiosonde, which transmits data from the counter together with meteorological parameters and GPS-derived position to a ground based receiver at 1 Hz rate. Statistically significant particle size distributions can be obtained once a second for number concentrations down to about 100,000 particle per litre (within the measured size range), or correspondingly less at lower temporal resolutions. At the same time, the counter is capable of measuring dust number concentrations exceeding a million per litre without incurring significant errors. Soundings during the DREAME campaign in Kuwait (Ulanowski et al. EGU 2010, AS4.7) and on Cape Verde Islands (Nicoll et al. EGU 2010, AS4.7) provided dust concentration profiles with a typical vertical resolution of 4 m. Comparisons with integrated dust column size distribution measurements from AERONET sun photometers showed good agreement in two out of three cases where near-simultaneous retrievals were available. Optical thickness calculations based on the size distributions measured in Kuwait, with the assumption that the dust particles were prolate spheroids, agreed with the AERONET optical thickness at 675 nm to within 15%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160005914','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160005914"><span id="translatedtitle">Nature, Origin, Potential Composition, and Climate Impact of the Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> (ATAL)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fairlie, T. D.; Vernier, J.-P.; Thomason, L. W.; Natarajan, M.; Bedka, K.; Wienhold, F.; Bian J.; Martinsson, B.</p> <p>2015-01-01</p> <p>Satellite observations from SAGE II and CALIPSO indicate that summertime <span class="hlt">aerosol</span> extinction has more than doubled in the Asian Tropopause <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> (ATAL) since the late 1990s. Here we show remote and in-situ observations, together with results from a chemical transport model (CTM), to explore the likely composition, origin, and radiative forcing of the ATAL. We show in-situ balloon measurements of <span class="hlt">aerosol</span> backscatter, which support the high levels observed by CALIPSO since 2006. We also show in situ measurements from aircraft, which indicate a predominant carbonaceous contribution to the ATAL (Carbon/Sulfur ratios of 2- 10), which is supported by the CTM results. We show that the peak in ATAL <span class="hlt">aerosol</span> lags by 1 month the peak in CO from MLS, associated with deep convection over Asia during the summer monsoon. This suggests that secondary formation and growth of <span class="hlt">aerosols</span> in the upper troposphere on monthly timescales make a significant contribution to ATAL. Back trajectory calculations initialized from CALIPSO observations provide evidence that deep convection over India is a significant source for ATAL through the vertical transport of pollution to the upper troposphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016BoLMe.tmp...64Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016BoLMe.tmp...64Y&link_type=ABSTRACT"><span id="translatedtitle">Sensitivity of Turbine-<span class="hlt">Height</span> Wind Speeds to Parameters in Planetary Boundary-<span class="hlt">Layer</span> and Surface-<span class="hlt">Layer</span> Schemes in the Weather Research and Forecasting Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Ben; Qian, Yun; Berg, Larry K.; Ma, Po-Lun; Wharton, Sonia; Bulaevskaya, Vera; Yan, Huiping; Hou, Zhangshuan; Shaw, William J.</p> <p>2016-07-01</p> <p>We evaluate the sensitivity of simulated turbine-<span class="hlt">height</span> wind speeds to 26 parameters within the Mellor-Yamada-Nakanishi-Niino (MYNN) planetary boundary-<span class="hlt">layer</span> scheme and MM5 surface-<span class="hlt">layer</span> scheme of the Weather Research and Forecasting model over an area of complex terrain. An efficient sampling algorithm and generalized linear model are used to explore the multiple-dimensional parameter space and quantify the parametric sensitivity of simulated turbine-<span class="hlt">height</span> wind speeds. The results indicate that most of the variability in the ensemble simulations is due to parameters related to the dissipation of turbulent kinetic energy (TKE), Prandtl number, turbulent length scales, surface roughness, and the von Kármán constant. The parameter associated with the TKE dissipation rate is found to be most important, and a larger dissipation rate produces larger hub-<span class="hlt">height</span> wind speeds. A larger Prandtl number results in smaller nighttime wind speeds. Increasing surface roughness reduces the frequencies of both extremely weak and strong airflows, implying a reduction in the variability of wind speed. All of the above parameters significantly affect the vertical profiles of wind speed and the magnitude of wind shear. The relative contributions of individual parameters are found to be dependent on both the terrain slope and atmospheric stability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A21H0250B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A21H0250B"><span id="translatedtitle">Assessment of planetary boundary <span class="hlt">layer</span> and residual <span class="hlt">layer</span> <span class="hlt">heights</span> in the Northeastern U.S. using Lidar, a network of surface observations, and the WRF-STILT model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barrera, Y.; Nehrkorn, T.; Hegarty, J. D.; Wofsy, S. C.; Gottlieb, E.; Sargent, M. R.; Decola, P.; Jones, T.</p> <p>2015-12-01</p> <p>Simulation of the planetary boundary <span class="hlt">layer</span> (PBL) and residual <span class="hlt">layer</span> (RL) are key requirements for forecasting air quality in cities and detecting transboundary air pollution events. This study combines information from a network of Mini Micropulse Lidar (MPL) instruments, the CALIOP satellite, meteorological and air pollution measuring sensors, and a particle-transport model to critically test mesoscale transport models at the regional level. <span class="hlt">Aerosol</span> backscattering measurements were continuously taken with MPL units in various locations within the Northeastern U.S., between September 2012 to August 2015. Data is analyzed using wavelet covariance transforms and image processing techniques. Initial results for the city of Boston show a PBL growth rate between approx. 150 and 300 meters per hour, in the morning to early afternoon (~12-19 UTC). The RL was present throughout the night and day at approx. 1.3 to 2.0 km. Transboundary air pollution events were detected and quantified, and variations in concentrations of greenhouse gases and <span class="hlt">aerosols</span> were also evaluated. Results were compared to information retrieved from Weather and Research Forecasting (WRF) model and the Stochastic Time-Inverted Lagrangian Transport (STILT) model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.9403K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.9403K&link_type=ABSTRACT"><span id="translatedtitle">Secondary <span class="hlt">aerosol</span> formation in the planetary boundary <span class="hlt">layer</span>: observations on board on a Zeppelin and analysis by back plume approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kazanas, Konstantinos; Rubach, Florian; Tillmann, Ralf; Mentel, Thomas; Elbern, Hendrik; Wahner, Andreas; Zeppelin Pegasos-Team 2012</p> <p>2014-05-01</p> <p>The airship Zeppelin NT is an airborne platform capable of flying at low speed throughout the entire planetary boundary <span class="hlt">layer</span> (PBL), thus the Zeppelin is an ideal platform to study regional processes in the lowest <span class="hlt">layers</span> of the atmosphere with high spatial resolution. Atmospheric <span class="hlt">aerosol</span> as a medium long lived tracer substance is of particular interest due to its influence on the global radiation budget. Due to its lifetime of up to several days secondary <span class="hlt">aerosol</span> at a certain location can result from local production or from transport processes. Flight patterns during the PEGASOS campaign 2012 in the Po Valley included vertical profiles and transects through regions of interest We analysed one flight with North-South transects between the Apennin and San Pietro Capofiume and one flight with vertical profiles near the supersite San Pietro Capofiume to shed light on local production and transport processes. Model analyses were performed by using 12 hour back plumes for selected points of measurements to determine the regions which contributed to the air mass under observation. This analysis was done using the EURopean Air pollution Dispersion and Inverse Modelling (EURAD-IM) system. As a novel method, adjoint (backward) plumes are applied to identify the spread of originating air masses in terms of horizontal and vertical extension, and the influence of precursor species. Flight patterns include 5 points of measurement along the transect on 21.06.2012 and the lowest (ca. 80m), highest (ca. 708m), and medium <span class="hlt">height</span> (299 to 464m) of 7 vertical profiles on the 20.06.2012.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.A33C0259L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.A33C0259L"><span id="translatedtitle">Effective Lidar Ratios of Dense Dust <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> over North Africa Observed by the CALIPSO Lidar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Z.; Winker, D. M.; Omar, A. H.; Vaughan, M.; Trepte, C. R.; Hu, Y.; Hostetler, C. A.; Sun, W.; Lin, B.</p> <p>2009-12-01</p> <p>The Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, a joint US and French mission, was launched three years ago to provide new insight into the role that clouds and <span class="hlt">aerosols</span> play in regulating Earth's weather, climate, and air quality. A key instrument on board the CALIPSO payload is a two-wavelength, polarization-sensitive backscatter lidar. With its capabilities of depolarization ratio measurement and high resolution profiling, the CALIPSO lidar provides a unique opportunity to study the dust <span class="hlt">aerosol</span> globally. Currently, a cloud and <span class="hlt">aerosol</span> discrimination (CAD) algorithm that incorporates five-dimensional probability distribution function (5D-PDF) is being developed for implementation in future data releases. This new 5D-PDF approach allows nearly unambiguous identification of dense dust <span class="hlt">layers</span> over/near their source regions and therefore enables the study of these <span class="hlt">layers</span> using a large amount of the CALIPSO data. Lidar ratio (i.e., extinction-to-backscatter ratio) is an intrinsic optical property of <span class="hlt">aerosols</span> and a key parameter necessary in the lidar signal inversion to retrieve profiles of <span class="hlt">aerosol</span> extinction and backscatter coefficients, which are two primary products of the CALIPSO level 2 data. This parameter is usually selected in the CALIPSO lidar level 2 data processing based on the <span class="hlt">aerosol</span> type identified. (Six types of <span class="hlt">aerosols</span> have been modeled: dust, polluted dust, marine, continental, polluted continental, and smoke.) As more data is being collected by the CALIPSO lidar, validation studies with the CALIPSO measurements are being performed and are now becoming available. For opaque dust <span class="hlt">layers</span>, the effective lidar ratio (the product of lidar ratio and multiple scattering factor) can be determined easily from integrated attenuated backscatter over the <span class="hlt">layer</span> top and apparent base. We have performed an extensive analysis based on the first two and a half years (June 2006 - December 2008) of the CALIPSO lidar nighttime</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013Ge%26Ae..53..104L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Ge%26Ae..53..104L"><span id="translatedtitle">Empirical model of variations in the IR Atmospheric system of molecular oxygen: 2. Emitting <span class="hlt">layer</span> <span class="hlt">height</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lipatov, K. V.</p> <p>2013-01-01</p> <p>The empirical regularities in the variations in the emitting <span class="hlt">layer</span> parameters depending on the solar zenith angle have been obtained by analyzing and systematizing the data published on the vertical distribution of the volume emission rate of the 1.27 μm molecular oxygen Infrared Atmospheric system measured on rockets and satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013PhDT........90Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013PhDT........90Y&link_type=ABSTRACT"><span id="translatedtitle">Investigation of wintertime cold-air pools and <span class="hlt">aerosol</span> <span class="hlt">layers</span> in the Salt Lake Valley using a lidar ceilometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Young, Joseph Swyler</p> <p></p> <p>This thesis investigates the utility of lidar ceilometers, a type of <span class="hlt">aerosol</span> lidar, in improving the understanding of meteorology and air quality in persistent wintertime stable boundary <span class="hlt">layers</span>, or cold-air pools, that form in urbanized valley and basin topography. This thesis reviews the scientific literature to survey the present knowledge of persistent cold-air pools, the operating principles of lidar ceilometers, and their demonstrated utility in meteorological investigations. Lidar ceilometer data from the Persistent Cold-Air Pool Study (PCAPS) are then used with meteorological and air quality data from other in situ and remote sensing equipment to investigate cold-air pools that formed in Utah's Salt Lake Valley during the winter of 2010-2011. The lidar ceilometer is shown to accurately measure <span class="hlt">aerosol</span> <span class="hlt">layer</span> depth and <span class="hlt">aerosol</span> loading, when compared to visual observations. A linear relationship is found between low-level lidar backscatter and surface particulate measurements. Convective boundary <span class="hlt">layer</span> lidar analysis techniques applied to cold-air pool ceilometer profiles can detect useful <span class="hlt">layer</span> characteristics. Fine-scale waves are observed and analyzed within the <span class="hlt">aerosol</span> <span class="hlt">layer</span>, with emphasis on Kelvin-Helmholz waves. Ceilometer <span class="hlt">aerosol</span> backscatter profiles are analyzed to quantify and describe mixing processes in persistent cold-air pools. Overlays of other remote and in-situ observations are combined with ceilometer particle backscatter to describe specific events during PCAPS. This analysis describes the relationship between the <span class="hlt">aerosol</span> <span class="hlt">layer</span> and the valley inversion as well as interactions with large-scale meteorology. The ceilometer observations of hydrometers are used to quantify cloudiness and precipitation during the project, observing that 50% of hours when a PCAP was present had clouds or precipitation below 5 km above ground level (AGL). Then, combining an objective technique for determining hourly <span class="hlt">aerosol</span> <span class="hlt">layer</span> depths and correcting this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ISPAn.II8...13M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ISPAn.II8...13M"><span id="translatedtitle">To examine the association between oscillations of the stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span> peaks and different types of clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mane, P. B.</p> <p>2014-11-01</p> <p><span class="hlt">Aerosol</span> measurements have been carried out at Kolhapur (16°42'N, 74°14'E) by using newly designed Semiautomatic Twilight Photometer. The system is a ground based simple and inexpensive but very sensitive passive remote sensing technique. The altitudes of the Junge <span class="hlt">layer</span> peaks on measurement days were derived from the <span class="hlt">aerosol</span> vertical profiles. One attempt is made to examine the association between oscillations of the stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span> peaks and different types of clouds. The values of AND for the Junge <span class="hlt">layer</span> peaks for each observational day were also calculated. The graph between AND at peak point of Junge <span class="hlt">layer</span> and day numbers was also studied in comparison with High, Medium and Low level clouds. There is an annual variation in the altitude of the peak of Junge <span class="hlt">layer</span> also. Its maximum is observed during January. The annual variation of the altitude of the peak of Junge <span class="hlt">layer</span> and the AND of Junge <span class="hlt">layer</span> peak showed opposite phase relation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JGRD..11314211H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JGRD..11314211H"><span id="translatedtitle">Analysis of <span class="hlt">aerosol</span> vertical distribution and variability in Hong Kong</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Qianshan; Li, Chengcai; Mao, Jietai; Lau, Alexis Kai-Hon; Chu, D. A.</p> <p>2008-07-01</p> <p><span class="hlt">Aerosol</span> vertical distribution is an important piece of information to improve <span class="hlt">aerosol</span> retrieval from satellite remote sensing. <span class="hlt">Aerosol</span> extinction coefficient profile and its integral form, <span class="hlt">aerosol</span> optical depth (AOD), as well as atmospheric boundary <span class="hlt">layer</span> (ABL) <span class="hlt">height</span> and haze <span class="hlt">layer</span> <span class="hlt">height</span> can be derived using lidar measurements. In this paper, we used micropulse lidar measurements acquired from May 2003 to June 2004 to illustrate seasonal variations of AOD and ABL <span class="hlt">height</span> in Hong Kong. On average, about 64% of monthly mean <span class="hlt">aerosol</span> optical depths were contributed by <span class="hlt">aerosols</span> within the mixing <span class="hlt">layer</span> (with a maximum (˜76%) in November and a minimum (˜55%) in September) revealing the existence of large abundance of <span class="hlt">aerosols</span> above ABL due to regional transport. The characteristics of seasonal averaged <span class="hlt">aerosol</span> profiles over Hong Kong in the study period are presented to illustrate seasonal phenomena of <span class="hlt">aerosol</span> transport and associated meteorological conditions. The correlation between AOD and surface extinction coefficient, as found, is generally poor (r2 ˜0.42) since elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> increase columnar <span class="hlt">aerosol</span> abundance but not extinction at surface. The typical <span class="hlt">aerosol</span> extinction profile in the ABL can be characterized by a low value near the surface and values increased with altitude reaching the top of ABL. When <span class="hlt">aerosol</span> vertical profile is assumed, surface extinction coefficient can be derived from AOD using two algorithms, which are discussed in detail in this paper. Preliminary analysis showed that better estimates of the extinction coefficient at the ground level could be obtained using two-<span class="hlt">layer</span> <span class="hlt">aerosol</span> extinction profiles (r2 ˜0.78, slope ˜0.82, and intercept ˜0.15) than uniform profiles of extinction with <span class="hlt">height</span> within the ABL (r2 ˜0.65, slope ˜0.27, and intercept ˜0.03). The improvement in correlation is promising on mapping satellite retrieved AOD to surface <span class="hlt">aerosol</span> extinction coefficient for urban and regional environmental studies on air</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRD..119.4859L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRD..119.4859L"><span id="translatedtitle"><span class="hlt">Aerosol</span> properties and their influences on marine boundary <span class="hlt">layer</span> cloud condensation nuclei at the ARM mobile facility over the Azores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Logan, Timothy; Xi, Baike; Dong, Xiquan</p> <p>2014-04-01</p> <p>A multiplatform data set from the Clouds, <span class="hlt">Aerosol</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span> (MBL) Graciosa, Azores, 2009-2010 field campaign was used to investigate how continental <span class="hlt">aerosols</span> can influence MBL cloud condensation nuclei (CCN) number concentration (NCCN). The seasonal variations of <span class="hlt">aerosol</span> properties have shown that the winter and early spring months had the highest mean surface wind speed (> 5 m s-1) and greatest contribution of sea salt to <span class="hlt">aerosol</span> optical depth (AOD), while continental fine mode <span class="hlt">aerosols</span> were the main contributors to AOD during the warm season months (May-September). Five <span class="hlt">aerosol</span> events consisting of mineral dust, pollution, biomass smoke, and volcanic ash particles were selected as case studies using Atmospheric Radiation Measurement (ARM) mobile facility measurements. The <span class="hlt">aerosols</span> in Case I were found to primarily consist of coarse mode, Saharan mineral dust. For Case II, the <span class="hlt">aerosols</span> were also coarse mode but consisted of volcanic ash. Case III had fine mode biomass smoke and pollution <span class="hlt">aerosol</span> influences while Cases IV and V consisted of mixtures of North American pollution and Saharan dust that was advected by an extratropical cyclone to the Azores. Cases I, IV, and V exhibited weak correlations between <span class="hlt">aerosol</span> loading and NCCN due to mineral dust influences, while Cases II and III had a strong relationship with NCCN likely due to the sulfate content in the volcanic ash and pollution particles. The permanent Eastern North Atlantic ARM facility over the Azores will aid in a future long-term study of <span class="hlt">aerosol</span> effects on NCCN.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A43G0366F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A43G0366F&link_type=ABSTRACT"><span id="translatedtitle">The Impact of Monthly Variation of the Pacific-North America (PNA) Teleconnection Pattern on Wintertime Surface-<span class="hlt">layer</span> <span class="hlt">Aerosol</span> Concentrations in the United States</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feng, J.; Liao, H.; Li, J.</p> <p>2015-12-01</p> <p>The Pacific-North America teleconnection (PNA) is the leading general circulation pattern in the troposphere over the region of North Pacific to North America during wintertime. The PNA exhibits positive (negative) phases with positive (negative) anomalies in geopotential <span class="hlt">height</span> in the vicinity of Hawaii and over the intermountain region of North America, and negative (positive) anomalies in geopotential <span class="hlt">height</span> over south of the Aleutian Islands and the Gulf Coast region of the United States. This study examined the impacts of monthly variation of the PNA phase on wintertime surface-<span class="hlt">layer</span> <span class="hlt">aerosol</span> concentrations in the United States by analyzing observations during 1999-2013 from the Air Quality System of Environmental Protection Agency (EPA-AQS) and the model results for 1986-2006 from the global three-dimensional Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). The composite analyses on the EPA-AQS observations over 1999-2003 showed that the average PM2.5 concentrations were higher in the PNA positive phases than in the PNA negative phases by 1.0 μg m-3 (8.6%), 2.1μg m-3 (24.1%), and 1.1 μg m-3 (10.6%) in the eastern, western, and whole of United States, respectively. Relative to the PNA negative phases, the number of exceedance days (days with the PM2.5 concentrations exceeding 35 μg m-3) in the PNA positive phases increased by 5-8 days month-1 in California and the contiguous Great Salt Lake and by 2-3 days month-1 in Iowa. The simulated geographical patterns of the differences in concentrations of PM2.5, nitrate, sulfate, ammonium, OC, and BC between the PNA positive and negative phases were similar to observations. The PNA influences surface-<span class="hlt">layer</span> <span class="hlt">aerosol</span> concentrations in the United States by changing meteorological variables such as temperature, precipitation, planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span>, relative humidity, and wind speed. We found that that the PNA-induced variation in planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> was the most dominant</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016BoLMe.tmp...22L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016BoLMe.tmp...22L"><span id="translatedtitle">A Numerical Study of Sea-Spray <span class="hlt">Aerosol</span> Motion in a Coastal Thermal Internal Boundary <span class="hlt">Layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Tinghao; Yu, Xiping</p> <p>2016-03-01</p> <p>A three-dimensional large-eddy simulation model is applied to the study of sea-spray <span class="hlt">aerosol</span> transport, dispersion and settling in the coastal thermal internal boundary <span class="hlt">layer</span> (IBL) formed by cool airflow from the open sea to the warm land. An idealized situation with constant inflow from the ocean and constant heat flux over the coastal land is considered. The numerical results confirm that the thickness of the coastal thermal IBL increases with the distance from the coastline until the outer edge of the IBL penetrates into the capping inversion <span class="hlt">layer</span>. The thickness increases also with time until a fully-developed thermal boundary <span class="hlt">layer</span> is formed. In addition, the thickness of the coastal thermal IBL increases more rapidly when the heat flux over the land is greater. Existence of large-scale eddies within the thermal IBL is identified and the turbulence intensity within the thermal IBL is also found to be significantly higher than that above. It is also indicated that the vertical position of the maximum concentration does not occur at the surface but increases as sea-spray <span class="hlt">aerosols</span> are transported inland. The vertical position of the maximum flux of sea-spray <span class="hlt">aerosols</span> within the coastal thermal IBL is shown to coincide with that of the maximum vertical velocity fluctuations when the coastal thermal IBL is fully developed with increased distance in the airflow direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016BoLMe.160..347L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016BoLMe.160..347L"><span id="translatedtitle">A Numerical Study of Sea-Spray <span class="hlt">Aerosol</span> Motion in a Coastal Thermal Internal Boundary <span class="hlt">Layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Tinghao; Yu, Xiping</p> <p>2016-08-01</p> <p>A three-dimensional large-eddy simulation model is applied to the study of sea-spray <span class="hlt">aerosol</span> transport, dispersion and settling in the coastal thermal internal boundary <span class="hlt">layer</span> (IBL) formed by cool airflow from the open sea to the warm land. An idealized situation with constant inflow from the ocean and constant heat flux over the coastal land is considered. The numerical results confirm that the thickness of the coastal thermal IBL increases with the distance from the coastline until the outer edge of the IBL penetrates into the capping inversion <span class="hlt">layer</span>. The thickness increases also with time until a fully-developed thermal boundary <span class="hlt">layer</span> is formed. In addition, the thickness of the coastal thermal IBL increases more rapidly when the heat flux over the land is greater. Existence of large-scale eddies within the thermal IBL is identified and the turbulence intensity within the thermal IBL is also found to be significantly higher than that above. It is also indicated that the vertical position of the maximum concentration does not occur at the surface but increases as sea-spray <span class="hlt">aerosols</span> are transported inland. The vertical position of the maximum flux of sea-spray <span class="hlt">aerosols</span> within the coastal thermal IBL is shown to coincide with that of the maximum vertical velocity fluctuations when the coastal thermal IBL is fully developed with increased distance in the airflow direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012ACP....12.9057W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012ACP....12.9057W&link_type=ABSTRACT"><span id="translatedtitle">Interpretation of FRESCO cloud retrievals in case of absorbing <span class="hlt">aerosol</span> events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, P.; Tuinder, O. N. E.; Tilstra, L. G.; de Graaf, M.; Stammes, P.</p> <p>2012-10-01</p> <p>Cloud and <span class="hlt">aerosol</span> information is needed in trace gas retrievals from satellite measurements. The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO) cloud algorithm employs reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud fraction. In general, clouds contribute more to the O2 A band reflectance than <span class="hlt">aerosols</span>. Therefore, the FRESCO algorithm does not correct for <span class="hlt">aerosol</span> effects in the retrievals and attributes the retrieved cloud information entirely to the presence of clouds, and not to <span class="hlt">aerosols</span>. For events with high <span class="hlt">aerosol</span> loading, <span class="hlt">aerosols</span> may have a dominant effect, especially for almost cloud free scenes. We have analysed FRESCO cloud data and Absorbing <span class="hlt">Aerosol</span> Index (AAI) data from the Global Ozone Monitoring Experiment (GOME-2) instrument on the Metop-A satellite for events with typical absorbing <span class="hlt">aerosol</span> types, such as volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated with the AAI data for these absorbing <span class="hlt">aerosol</span> events and that the FRESCO cloud pressure contains information on <span class="hlt">aerosol</span> <span class="hlt">layer</span> pressure. For cloud free scenes, the derived FRESCO cloud pressure is close to the <span class="hlt">aerosol</span> <span class="hlt">layer</span> pressure, especially for optically thick <span class="hlt">aerosol</span> <span class="hlt">layers</span>. For cloudy scenes, if the strongly absorbing <span class="hlt">aerosols</span> are located above the clouds, then the retrieved FRESCO cloud pressure may represent the <span class="hlt">height</span> of the <span class="hlt">aerosol</span> <span class="hlt">layer</span> rather than the <span class="hlt">height</span> of the clouds. Combining FRESCO and AAI data, an estimate for the <span class="hlt">aerosol</span> <span class="hlt">layer</span> pressure can be given.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26071961','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26071961"><span id="translatedtitle">Impacts of elevated-<span class="hlt">aerosol-layer</span> and <span class="hlt">aerosol</span> type on the correlation of AOD and particulate matter with ground-based and satellite measurements in Nanjing, southeast China.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Han, Yong; Wu, Yonghua; Wang, Tijian; Zhuang, Bingliang; Li, Shu; Zhao, Kun</p> <p>2015-11-01</p> <p>Assessment of the correlation between <span class="hlt">aerosol</span> optical depth (AOD) and particulate matter (PM) is critical to satellite remote sensing of air quality, e.g. ground PM10 and ground PM2.5. This study evaluates the impacts of aloft-<span class="hlt">aerosol</span>-plume and <span class="hlt">aerosol</span>-type on the correlation of AOD-PM by using synergistic measurement of a polarization-sensitive Raman-Mie lidar, CIMEL sunphotometer (SP) and TEOM PM samplers, as well as the satellite MODIS and CALIPSO, during April to July 2011 in Nanjing city (32.05(○)N/118.77(○)E), southeast China. Aloft-<span class="hlt">aerosol-layer</span> and <span class="hlt">aerosol</span> types (e.g. dust and non-dust or urban <span class="hlt">aerosol</span>) are identified with the range-resolved polarization lidar and SP measurements. The results indicate that the correlations for AOD-PM10 and AOD-PM2.5 can be much improved when screening out the aloft-<span class="hlt">aerosol-layer</span>. The linear regression slopes show significant differences for the dust and non-dust dominant <span class="hlt">aerosols</span> in the planetary boundary <span class="hlt">layer</span> (PBL). In addition, we evaluate the recent released MODIS-AOD product (Collection 6) from the "dark-target" (DT) and "deep-blue" (DB) algorithms and their correlation with the PM in Nanjing urban area. The results verify that the MODIS-DT AODs show a good correlation (R = 0.89) with the SP-AOD but with a systematic overestimate. In contrast, the MODIS-DB AOD shows a moderate correlation (R = 0.66) with the SP-AOD but with a smaller regression intercept (0.07). Furthermore, the moderately high correlations between the MODIS-AOD and PM10 (PM2.5) are indicated, which suggests the feasibility of PM estimate using the MODIS-AOD in Nanjing city. PMID:26071961</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20050176525&hterms=seasons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dseasons','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20050176525&hterms=seasons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dseasons"><span id="translatedtitle">Coordinated Airborne, Spaceborne and Ground-based Measurements of Massive Thick <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> during the Dry Season in Southern Africa</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmid, B.; Redemann, J.; Russell, P. B.; Hobbs, P. V.; Hlavka, D. L.; McGill, M. J.; Holben, B. N.; Welton, E. J.; Campbell, J. R.; Torres, O.</p> <p>2003-01-01</p> <p>During the dry season airborne campaign of the Southern African Regional Science Initiative (SAFARI 2000), coordinated observations were made of massive thick <span class="hlt">aerosol</span> <span class="hlt">layers</span>. These <span class="hlt">layers</span> were often dominated by <span class="hlt">aerosols</span> from biomass burning. We report on airborne Sun photometer measurements of <span class="hlt">aerosol</span> optical depth (lambda = 0.354- 1.557 microns), columnar water vapor, and vertical profiles of <span class="hlt">aerosol</span> extinction and water vapor density that were obtained aboard the University of Washington's Convair-580 research aircraft. We compare these with ground-based AERONET Sun/sky radiometer results, with ground based lidar data (MPL-Net), and with measurements from a downward pointing lidar aboard the high-flying NASA ER-2 aircraft. Finally, we show comparisons between <span class="hlt">aerosol</span> optical depths fiom the Sun photometer and those retrieved over land and over water using four spaceborne sensors (TOMS, MODIS, MISR, and ATSR-2).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020064477&hterms=seasons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dseasons','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020064477&hterms=seasons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dseasons"><span id="translatedtitle">Coordinated Airborne, Spaceborne, and Ground-Based Measurements of Massive, Thick <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> During the Dry Season in Southern Africa</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmid, B.; Redemann, J.; Russell, P. B.; Hobbs, P. V.; Hlavka, D. L.; McGill, M. J.; Holben, B. N.; Welton, E. J.; Campbell, J.; Torres, O.; Hipskind, R. Stephen (Technical Monitor)</p> <p>2002-01-01</p> <p>During the dry-season airborne campaign of the Southern African Regional Science Initiative (SAFARI 2000), unique coordinated observations were made of massive, thick <span class="hlt">aerosol</span> <span class="hlt">layers</span>. These <span class="hlt">layers</span> were often dominated by <span class="hlt">aerosols</span> from biomass burning. We report on airborne Sunphotometer measurements of <span class="hlt">aerosol</span> optical depth (lambda=354-1558 nm), columnar water vapor, and vertical profiles of <span class="hlt">aerosol</span> extinction and water vapor density that were obtained aboard the University of Washington's Convair-580 research aircraft. We compare these with ground-based AERONET Sun/sky radiometer results, with ground based lidar data MPL-Net), and with measurements from a downward-pointing lidar aboard the high-flying NASA ER-2 aircraft. Finally, we show comparisons between <span class="hlt">aerosol</span> optical depths from the Sunphotometer and those retrieved over land and over water using four spaceborne sensors (TOMS (Total Ozone Mapping Spectrometer), MODIS (Moderate Resolution Imaging Spectrometer), MISR (Multiangle Imaging Spectroradiometer) and ATSR-2 (Along Track Scanning Radiometer)).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016BoLMe.158..165P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016BoLMe.158..165P"><span id="translatedtitle">Seeing the Fields and Forests: Application of Surface-<span class="hlt">Layer</span> Theory and Flux-Tower Data to Calculating Vegetation Canopy <span class="hlt">Height</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pennypacker, Sam; Baldocchi, Dennis</p> <p>2016-02-01</p> <p>Canopy <span class="hlt">height</span> is an important and dynamic site variable that affects the mass and energy exchanges between vegetation and the atmosphere. We develop a method to estimate canopy <span class="hlt">height</span> routinely, using surface-<span class="hlt">layer</span> theory and turbulence measurements made from a collection of flux towers. This tool is based on connecting the logarithmic wind profile generally expected in a neutral surface <span class="hlt">layer</span> with direct measurements of friction velocity and assumptions about canopy <span class="hlt">height</span>'s relationships with zero-plane displacement and aerodynamic roughness length. Tests over a broad range of canopy types and <span class="hlt">heights</span> find that calculated values are in good agreement with direct measurements of canopy <span class="hlt">height</span>, including in a heterogeneous landscape. Based on the various uncertainties associated with our starting assumptions about canopy micrometeorology, we present a blueprint for future work that is necessary for expanding and improving these initial calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.A21D0072K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.A21D0072K&link_type=ABSTRACT"><span id="translatedtitle">Characteristics of <span class="hlt">aerosol</span> at a lower atmospheric <span class="hlt">layer</span> in DRAGON field campaign</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>KUJI, M.; Azuma, Y.; Kitakoga, S.; Sano, I.; Holben, B. N.</p> <p>2013-12-01</p> <p>Air pollution arises severely over East Asia with the rapid economic development nowadays. Monitoring the atmospheric environment, as one of the purposes, an intensive field campaign, Distributed Regional <span class="hlt">Aerosol</span> Gridded Observation Networks (DRAGON), was carried out in the spring of year 2012, led by National Aeronautics and Space Administration (NASA). At that time, atmospheric phenomena such as Yellow sand and haze events were observed at Nara in the western part of Japan, as one of the DRAGON observation sites. The atmospheric events were characterized with the <span class="hlt">AErosol</span> RObotic NETwork (AERONET) data. As a result of the data analysis, it was found that more light-absorbing and smaller particles dominated at the lower than upper atmospheric <span class="hlt">layer</span> for the Kosa event in particular. A backward trajectory analysis suggested that the Yellow sand event traveled over the East Asian industrial cities, which could lead to a mixture of sand and air pollutants with moderate particle size and light-absorptivity. In addition, visibility observation was evaluated quantitatively with AERONET data in the DRAGON campaign since eye observation was inherently semi-quantitative. The extinction coefficient estimated from visibility was compared to that from AERONET. As a result, it was found that the extinction coefficients were generally consistent to each other. But there were some discrepancies, which could be caused with the atmospheric phenomena or <span class="hlt">aerosol</span> types. It is confirmed that visibility is strongly influenced with <span class="hlt">aerosols</span> in the case of severe atmospheric phenomena in particular.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1236497','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1236497"><span id="translatedtitle">Clouds, <span class="hlt">Aerosol</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span> (CAP-MBL) Final Campaign Report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wood, R.</p> <p>2016-01-01</p> <p>The extensive coverage of low clouds over the subtropical eastern oceans greatly impacts the current climate. In addition, the response of low clouds to changes in atmospheric greenhouse gases and <span class="hlt">aerosols</span> is a major source of uncertainty, which thwarts accurate prediction of future climate change. Low clouds are poorly simulated in climate models, partly due to inadequate long-term simultaneous observations of their macrophysical and microphysical structure, radiative effects, and associated <span class="hlt">aerosol</span> distribution in regions where their impact is greatest. The thickness and extent of subtropical low clouds is dependent on tight couplings between surface fluxes of heat and moisture, radiative cooling, boundary <span class="hlt">layer</span> turbulence, and precipitation (much of which evaporates before reaching the ocean surface and is closely connected to the abundance of cloud condensation nuclei). These couplings have been documented as a result of past field programs and model studies. However, extensive research is still required to achieve a quantitative understanding sufficient for developing parameterizations, which adequately predict <span class="hlt">aerosol</span> indirect effects and low cloud response to climate perturbations. This is especially true of the interactions between clouds, <span class="hlt">aerosol</span>, and precipitation. These processes take place in an ever-changing synoptic environment that can confound interpretation of short time period observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.4894P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.4894P&link_type=ABSTRACT"><span id="translatedtitle">Assessment of <span class="hlt">aerosol</span> optical property and radiative effect for the <span class="hlt">layer</span> decoupling cases over the northern South China Sea during the 7-SEAS/Dongsha Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pani, Shantanu Kumar; Wang, Sheng-Hsiang; Lin, Neng-Huei; Tsay, Si-Chee; Lolli, Simone; Chuang, Ming-Tung; Lee, Chung-Te; Chantara, Somporn; Yu, Jin-Yi</p> <p>2016-05-01</p> <p>The <span class="hlt">aerosol</span> radiative effect can be modulated by the vertical distribution and optical properties of <span class="hlt">aerosols</span>, particularly when <span class="hlt">aerosol</span> <span class="hlt">layers</span> are decoupled. Direct <span class="hlt">aerosol</span> radiative effects over the northern South China Sea (SCS) were assessed by incorporating an observed data set of <span class="hlt">aerosol</span> optical properties obtained from the Seven South East Asian Studies (7-SEAS)/Dongsha Experiment into a radiative transfer model. <span class="hlt">Aerosol</span> optical properties for a two-<span class="hlt">layer</span> structure of <span class="hlt">aerosol</span> transport were estimated. In the radiative transfer calculations, <span class="hlt">aerosol</span> variability (i.e., diversity of source region, <span class="hlt">aerosol</span> type, and vertical distribution) for the complex <span class="hlt">aerosol</span> environment was also carefully quantified. The column-integrated <span class="hlt">aerosol</span> optical depth (AOD) at 500 nm was 0.1-0.3 for near-surface <span class="hlt">aerosols</span> and increased 1-5 times in presence of upper <span class="hlt">layer</span> biomass-burning <span class="hlt">aerosols</span>. A case study showed the strong <span class="hlt">aerosol</span> absorption (single-scattering albedo (ω) ≈ 0.92 at 440 nm wavelength) exhibited by the upper <span class="hlt">layer</span> when associated with predominantly biomass-burning <span class="hlt">aerosols</span>, and the ω (≈0.95) of near-surface <span class="hlt">aerosols</span> was greater than that of the upper <span class="hlt">layer</span> <span class="hlt">aerosols</span> because of the presence of mixed type <span class="hlt">aerosols</span>. The presence of upper level <span class="hlt">aerosol</span> transport could enhance the radiative efficiency at the surface (i.e., cooling) and lower atmosphere (i.e., heating) by up to -13.7 and +9.6 W m-2 per AOD, respectively. Such enhancement could potentially modify atmospheric stability, can influence atmospheric circulation, as well as the hydrological cycle over the tropical and low-latitude marginal northern SCS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ACPD....715565Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ACPD....715565Z"><span id="translatedtitle">Dust <span class="hlt">aerosol</span> radiative effect and influence on urban atmospheric boundary <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, L.; Chen, M.; Li, L.</p> <p>2007-11-01</p> <p>An 1.5-level-closure and 3-D non-stationary atmospheric boundary <span class="hlt">layer</span> (ABL) model and a radiation transfer model with the output of Weather Research and Forecast (WRF) Model and lidar AML-1 are employed to simulate the dust <span class="hlt">aerosol</span> radiative effect and its influence on ABL in Beijing for the period of 23-26 January 2002 when a dust storm occurred. The simulation shows that daytime dust <span class="hlt">aerosol</span> radiative effect heats up the ABL at the mean rate of about 0.68 K/h. The horizontal wind speed from ground to 900 m <span class="hlt">layer</span> is also overall increased, and the value changes about 0.01 m/s at 14:00 LT near the ground. At night, the dust <span class="hlt">aerosol</span> radiative effect cools the ABL at the mean rate of -0.21 K/h and the wind speed lowers down at about -0.19 m/s at 02:00 LT near the ground.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080023467','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080023467"><span id="translatedtitle">LASE Measurements of Water Vapor, <span class="hlt">Aerosol</span>, and Cloud Distributions in Saharan Air <span class="hlt">Layers</span> and Tropical Disturbances</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ismail, Syed; Ferrare, Richard; Browell, Edward; Kooi, Susan; Notari, Anthony; Butler, Carolyn; Burton, Sharon; Fenn, Marta; Krishnamurti, T. N.; Dunion, Jason; Heymsfield, Gerry; Anderson, Bruce</p> <p>2008-01-01</p> <p>LASE (Lidar Atmospheric Sensing Experiment) onboard the NASA DC-8 was used to measure high resolution profiles of water vapor and <span class="hlt">aerosols</span>, and cloud distributions in 14 flights over the eastern Atlantic region during the NAMMA (NASA African Monsoon Multidisciplinary Analyses) field experiment, which was conducted from August 15 to September 12, 2006. These measurements were made in conjunction with flights designed to study African Easterly Waves (AEW), Tropical Disturbances (TD), and Saharan <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> (SALs) as well as flights performed in clear air and convective regions. As a consequence of their unique radiative properties and dynamics, SAL <span class="hlt">layers</span> have a significant influence in the development of organized convection associated with TD. Interactions of the SAL with tropical air during early stages of the development of TD were observed. These LASE measurements represent the first simultaneous water vapor and <span class="hlt">aerosol</span> lidar measurements to study the SAL and its impact on TDs and hurricanes. Seven AEWs were studied and four of these evolved into tropical storms and three did not. Three out of the four tropical storms evolved into hurricanes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A33B0155S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A33B0155S"><span id="translatedtitle">Interaction between <span class="hlt">aerosol</span> and the planetary boundary <span class="hlt">layer</span> depth at sites in the US and China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sawyer, V. R.</p> <p>2015-12-01</p> <p>The depth of the planetary boundary <span class="hlt">layer</span> (PBL) defines a changing volume into which pollutants from the surface can disperse, which affects weather, surface air quality and radiative forcing in the lower troposphere. Model simulations have also shown that <span class="hlt">aerosol</span> within the PBL heats the <span class="hlt">layer</span> at the expense of the surface, changing the stability profile and therefore also the development of the PBL itself: <span class="hlt">aerosol</span> radiative forcing within the PBL suppresses surface convection and causes shallower PBLs. However, the effect has been difficult to detect in observations. The most intensive radiosonde measurements have a temporal resolution too coarse to detect the full diurnal variability of the PBL, but remote sensing such as lidar can fill in the gaps. Using a method that combines two common PBL detection algorithms (wavelet covariance and iterative curve-fitting) PBL depth retrievals from micropulse lidar (MPL) at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site are compared to MPL-derived PBL depths from a multiyear lidar deployment at the Hefei Radiation Observatory (HeRO). With <span class="hlt">aerosol</span> optical depth (AOD) measurements from both sites, it can be shown that a weak inverse relationship exists between AOD and daytime PBL depth. This relationship is stronger at the more polluted HeRO site than at SGP. Figure: Mean daily AOD vs. mean daily PBL depth, with the Nadaraya-Watson estimator overlaid on the kernel density estimate. Left, SGP; right, HeRO.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.3263M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRD..121.3263M&link_type=ABSTRACT"><span id="translatedtitle">The impact of a boundary <span class="hlt">layer</span> <span class="hlt">height</span> formulation on the GEOS-5 model climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McGrath-Spangler, E. L.</p> <p>2016-04-01</p> <p>Planetary boundary <span class="hlt">layer</span> (PBL) processes are important for the estimation of surface-atmosphere exchanges that impact global climate. One way of characterizing the strength of these processes is the PBL depth. In the Goddard Earth Observing System (GEOS-5) atmospheric general circulation model, the PBL depth is also used in calculating the turbulent length scale, which, in turn, is used in estimating the turbulence and vertical mixing within the model. Therefore, changing the PBL depth definition directly affects the model climate. This study evaluates the climatological model response of two long-term simulations using different PBL depth definitions. The first definition is based on a bulk Richardson number; the second uses a combination of the same bulk Richardson number definition over land plus a definition based on the turbulent eddy diffusion coefficient over water. The two simulations produce different spatiotemporal patterns of temperature, specific humidity, and wind speed related to the differences in turbulence. The largest differences, as expected, are present over water. Due to differences in atmospheric stability, the relationship between the two PBL depth estimates differ among the majority of the oceans and off the west coasts of continents, affecting the climatic response. Due to its optimization of the climatic response while maintaining a realistic diurnal cycle of PBL depth, the mixed PBL depth configuration is preferred.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SPIE.4882..100Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SPIE.4882..100Q"><span id="translatedtitle">Global pollution <span class="hlt">aerosol</span> monitoring (GPAM) in the atmospheric boundary <span class="hlt">layer</span> using future earth observing satellite remote sensing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qu, Jianhe; Kafatos, Menas; Yang, Ruixin; Chiu, Long S.; Riebau, Allen R.</p> <p>2003-04-01</p> <p>Global pollution <span class="hlt">aerosol</span> monitoring is a very important climatic and environmental problem. It affects not only human health but also ecological systems. Because most pollution <span class="hlt">aerosols</span> are concentrated in the atmospheric boundary <span class="hlt">layer</span> where human, animal and vegetation live, global pollution <span class="hlt">aerosol</span> stuides have been an important topic since about a decade ago. Recently, many new chemistry remote sensing satellite systems, such as NASA's Aura (EOS-CHEM), have been established. However, pollution <span class="hlt">aerosols</span> in the atmospheric boundary <span class="hlt">layer</span> cannot be detected using current remote sensing technologies. George Mason University (GMU) proposes to design scientific algorithms and technologies to monitor the atmospheric boundary <span class="hlt">layer</span> pollution <span class="hlt">aerosols</span>, using both satellite remote sensing measurements and ground measurements, collaborating with NASA and the United States Department of Agriculture (USDA)/Forest Services (FS). Boundary <span class="hlt">layer</span> pollution <span class="hlt">aerosols</span> result from industrial pollution, desert dust storms, smoke from wildfires and biomass burning, volcanic eruptions, and from other trace gases. The current and next generation satellite instruments, such as The Ozone Mapping and Profiler Suite (OMPS), Ozone Monitoring Instrument (OMI), Thermal Emission Spectrometer (TES), and High Resolution Dynamics Limb Sounder (HIRDLS) can be used for this study. Some surface measurements from USDA/FS and other agencies may also be used in this study. We will discuss critical issues for GPAM in the boundary <span class="hlt">layer</span> using Earth observing satellite remote sensing in detail in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.3695G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.3695G&link_type=ABSTRACT"><span id="translatedtitle">Modeling the feedback between <span class="hlt">aerosol</span> and meteorological variables in the atmospheric boundary <span class="hlt">layer</span> during a severe fog-haze event over the North China Plain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Yi; Zhang, Meigen; Liu, Zirui; Wang, Lili; Wang, Pucai; Xia, Xiangao; Tao, Minghui; Zhu, Lingyun</p> <p>2016-04-01</p> <p>The feedback between <span class="hlt">aerosol</span> and meteorological variables in the atmospheric boundary <span class="hlt">layer</span> over the North China Plain (NCP) is analyzed by conducting numerical experiments with and without the <span class="hlt">aerosol</span> direct and indirect effects via a coupled meteorology and <span class="hlt">aerosol</span>/chemistry model(WRF-Chem). The numerical experiments are performed for the period of 2-26 January 2013, during which a severe fog-haze event (10-15 January 2013) occurred, with the simulated maximum hourly surface PM2.5 concentration of ~600 μg m-3, minimum atmospheric visibility of ~0.3 km, and 10-100 hours of simulated hourly surface PM2.5 concentration above 300 μg m-3 over NCP. A comparison of model results with <span class="hlt">aerosol</span> feedback against observations indicates that the model can reproduce the spatial and temporal characteristics of temperature, relative humidity (RH), wind, surface PM2.5 concentration, atmospheric visibility, and <span class="hlt">aerosol</span> optical depth reasonably well. Analysis of model results with and without <span class="hlt">aerosol</span> feedback shows that during the fog-haze event <span class="hlt">aerosols</span> lead to a significant negative radiative forcing of ~20 to ~140 W m-2 at the surface and a large positive radiative forcing of 20-120 W m-2 in the atmosphere and induce significant changes in meteorological variables with maximum changes during 09:00-18:00 local time (LT) over urban Beijing and Tianjin and south Hebei: the temperature decreases by 0.8-2.8 °C at the surface and increases by 0.1-0.5 °C at around 925 hPa, while RH increases by about 4-12% at the surface and decreases by 1-6% at around 925 hPa. As a result, the <span class="hlt">aerosol</span>-induced equivalent potential temperature profile change shows that the atmosphere is much more stable and thus the surface wind speed decreases by up to 0.3 m s-1 (10 %) and the atmosphere boundary <span class="hlt">layer</span> <span class="hlt">height</span> decreases by 40-200 m (5-30 %) during the daytime of this severe fog-haze event. Owing to this more stable atmosphere during 09:00-18:00, 10-15 January, compared to the surface PM2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ACP....15.4279G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ACP....15.4279G&link_type=ABSTRACT"><span id="translatedtitle">Modeling the feedback between <span class="hlt">aerosol</span> and meteorological variables in the atmospheric boundary <span class="hlt">layer</span> during a severe fog-haze event over the North China Plain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Y.; Zhang, M.; Liu, Z.; Wang, L.; Wang, P.; Xia, X.; Tao, M.; Zhu, L.</p> <p>2015-04-01</p> <p>The feedback between <span class="hlt">aerosol</span> and meteorological variables in the atmospheric boundary <span class="hlt">layer</span> over the North China Plain (NCP) is analyzed by conducting numerical experiments with and without the <span class="hlt">aerosol</span> direct and indirect effects via a coupled meteorology and <span class="hlt">aerosol</span>/chemistry model (WRF-Chem). The numerical experiments are performed for the period of 2-26 January 2013, during which a severe fog-haze event (10-15 January 2013) occurred, with the simulated maximum hourly surface PM2.5 concentration of ~600 ug m-3, minimum atmospheric visibility of ~0.3 km, and 10-100 hours of simulated hourly surface PM2.5 concentration above 300 ug m-3 over NCP. A comparison of model results with <span class="hlt">aerosol</span> feedback against observations indicates that the model can reproduce the spatial and temporal characteristics of temperature, relative humidity (RH), wind, surface PM2.5 concentration, atmospheric visibility, and <span class="hlt">aerosol</span> optical depth reasonably well. Analysis of model results with and without <span class="hlt">aerosol</span> feedback shows that during the fog-haze event <span class="hlt">aerosols</span> lead to a significant negative radiative forcing of -20 to -140 W m-2 at the surface and a large positive radiative forcing of 20-120 W m-2 in the atmosphere and induce significant changes in meteorological variables with maximum changes during 09:00-18:00 local time (LT) over urban Beijing and Tianjin and south Hebei: the temperature decreases by 0.8-2.8 °C at the surface and increases by 0.1-0.5 °C at around 925 hPa, while RH increases by about 4-12% at the surface and decreases by 1-6% at around 925 hPa. As a result, the <span class="hlt">aerosol</span>-induced equivalent potential temperature profile change shows that the atmosphere is much more stable and thus the surface wind speed decreases by up to 0.3 m s-1 (10%) and the atmosphere boundary <span class="hlt">layer</span> <span class="hlt">height</span> decreases by 40-200 m (5-30%) during the daytime of this severe fog-haze event. Owing to this more stable atmosphere during 09:00-18:00, 10-15~January, compared to the surface PM2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ACPD...15.1093G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ACPD...15.1093G&link_type=ABSTRACT"><span id="translatedtitle">Modeling the feedback between <span class="hlt">aerosol</span> and meteorological variables in the atmospheric boundary <span class="hlt">layer</span> during a severe fog-haze event over the North China Plain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Y.; Zhang, M.; Liu, Z.; Wang, L.; Wang, P.; Xia, X.; Tao, M.</p> <p>2015-01-01</p> <p>The feedback between <span class="hlt">aerosol</span> and meteorological variables in the atmospheric boundary <span class="hlt">layer</span> over the North China Plain is analyzed by conducting numerical experiments with and without the <span class="hlt">aerosol</span> direct and indirect effects via a coupled meteorology and <span class="hlt">aerosol</span>/chemistry model (WRF-Chem). The numerical experiments are performed for the period 2-26 January 2013, during which a severe fog-haze event (10-15 January 2013) occurred. Comparison of the model results with <span class="hlt">aerosol</span> feedback against observations indicates that the model can reproduce the spatial and temporal characteristics of temperature, relative humidity (RH), wind, surface PM2.5 concentration, atmospheric visibility, and <span class="hlt">aerosol</span> optical depth. Comparison of modeling results in the presence and absence of <span class="hlt">aerosol</span> feedback during the fog-haze event shows that <span class="hlt">aerosols</span> lead to a significant negative radiative forcing of -20 to -140 W m-2 at the surface and a large positive radiative forcing of 20-120 W m-2 in the atmosphere and induce significant changes in meteorological variables of which the maximum changes occur during 09:00-18:00 LT over urban Beijing and Tianjin, and south Hebei Province: the temperature decreases by 0.8-2.8 °C at the surface and increases by 0.1-0.5 °C at around 925 hPa while the RH increases by about 4-12% at the surface and decreases by 1-6% at around 925 hPa. As a result, the <span class="hlt">aerosol</span>-induced equivalent potential temperature profile change shows that the atmosphere is much more stable and thus the surface wind speed decreases by up to 0.3 m s-1 (10%) and the atmosphere boundary <span class="hlt">layer</span> <span class="hlt">height</span> decreases by 40-200 m (5-30%) during the daytime of this severe fog-haze event. Owing to this more stable atmosphere, during 09:00-18:00, 10-15 January, compared to the surface PM2.5 concentration from the model results without <span class="hlt">aerosol</span> feedback, the average surface PM2.5 concentration increases by 10-50 μg m-3 (2-30%) over Beijing, Tianjin, and south Hebei province and the maximum increase of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25105753','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25105753"><span id="translatedtitle">Impact of atmospheric boundary <span class="hlt">layer</span> depth variability and wind reversal on the diurnal variability of <span class="hlt">aerosol</span> concentration at a valley site.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pal, S; Lee, T R; Phelps, S; De Wekker, S F J</p> <p>2014-10-15</p> <p>The development of the atmospheric boundary <span class="hlt">layer</span> (ABL) plays a key role in affecting the variability of atmospheric constituents such as <span class="hlt">aerosols</span>, greenhouse gases, water vapor, and ozone. In general, the concentration of any tracers within the ABL varies due to the changes in the mixing volume (i.e. ABL depth). In this study, we investigate the impact on the near-surface <span class="hlt">aerosol</span> concentration in a valley site of 1) the boundary <span class="hlt">layer</span> dilution due to vertical mixing and 2) changes in the wind patterns. We use a data set obtained during a 10-day field campaign in which a number of remote sensing and in-situ instruments were deployed, including a ground-based <span class="hlt">aerosol</span> lidar system for monitoring of the ABL top <span class="hlt">height</span> (zi), a particle counter to determine the number concentration of <span class="hlt">aerosol</span> particles at eight different size ranges, and tower-based standard meteorological instruments. Results show a clearly visible decreasing trend of the mean daytime zi from 2900 m AGL (above ground level) to 2200 m AGL during a three-day period which resulted in increased near-surface pollutant concentrations. An inverse relationship exists between the zi and the fine fraction (0.3-0.7 μm) accumulation mode particles (AMP) on some days due to the dilution effect in a well-mixed ABL. These days are characterized by the absence of daytime upvalley winds and the presence of northwesterly synoptic-driven winds. In contrast, on the days with an onset of an upvalley wind circulation after the morning transition, the wind-driven local transport mechanism outweighs the ABL-dilution effect in determining the variability of AMP concentration. The interplay between the ABL depth evolution and the onset of the upvalley wind during the morning transition period significantly governs the air quality in a valley and could be an important component in the studies of mountain meteorology and air quality. PMID:25105753</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACPD...1533209F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACPD...1533209F"><span id="translatedtitle">The impact of monthly variation of the Pacific-North America (PNA) teleconnection pattern on wintertime surface-<span class="hlt">layer</span> <span class="hlt">aerosol</span> concentrations in the United States</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feng, J.; Liao, H.; Li, J.</p> <p>2015-11-01</p> <p>The Pacific-North America teleconnection (PNA) is the leading general circulation pattern in the troposphere over the region of North Pacific to North America during wintertime. This study examined the impacts of monthly variation of the PNA phase (positive or negative phase) on wintertime surface-<span class="hlt">layer</span> <span class="hlt">aerosol</span> concentrations in the US by analyzing observations during 1999-2013 from the Air Quality System of Environmental Protection Agency (EPA-AQS) and the model results for 1986-2006 from the global three-dimensional Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). The composite analyses on the EPA-AQS observations over 1999-2003 showed that the average concentrations of PM2.5, sulfate, nitrate, ammonium, organic carbon, and black carbon <span class="hlt">aerosols</span> over the US were higher in the PNA positive phases than in the PNA negative phases by 1.4 μg m-3 (12.7 %), 0.1 μg m-3 (6.4 %), 0.3 μg m-3 (39.1 %), 0.2 μg m-3 (22.8 %), 0.8 μg m-3 (21.3 %), and 0.2 μg m-3 (34.1 %), respectively. The simulated geographical patterns of the differences in concentrations of all <span class="hlt">aerosol</span> species between the PNA positive and negative phases were similar to observations. Based on the GEOS-Chem simulation driven by the assimilated meteorological fields, the PNA-induced variation in planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> was found to be the most dominant meteorological factor that influenced the concentrations of PM2.5, sulfate, ammonium, organic carbon, and black carbon, and the PNA-induced variation in temperature was the most important parameter that influenced nitrate <span class="hlt">aerosol</span>. Results from this work have important implications for understanding and prediction of air quality in the United States.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5928R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5928R"><span id="translatedtitle">Airborne measurements of hygroscopicity and mixing state of <span class="hlt">aerosols</span> in the planetary boundary <span class="hlt">layer</span> during the PEGASOS campaigns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosati, Bernadette; Weingartner, Ernest; Gysel, Martin; Rubach, Florian; Mentel, Thomas; Baltensperger, Urs</p> <p>2014-05-01</p> <p><span class="hlt">Aerosols</span> interact directly with the incident solar radiation by scattering or absorbing the light. The optical properties of an <span class="hlt">aerosol</span> particle can strongly be altered at enhanced relative humidity (RH). Depending on the particle's chemical composition, it can experience hygroscopic growth, leading to a change in size and index of refraction compared to the dry particle (Zieger et al., 2011). Besides, <span class="hlt">aerosols</span> can exist in different mixing states which are usually divided into internal and external mixtures. If all particles of a certain size have the same chemical composition, they are described as internally mixed, whereas if particles of equal size have different chemical composition, they are defined as externally mixed. Depending on the mixture the hygroscopic behavior will change: internally mixed <span class="hlt">aerosols</span> will grow uniformly with increasing RH, while the different substances in external mixtures will experience different growing behaviors leading to a mode-splitting or broadened size distribution. Laboratory studies are commonly performed at dry conditions but it is known that temperature and RH as well as chemical composition are changing with altitude (Morgan et al., 2010). This further leads to the conclusion that the in-situ measurements of optical properties at different <span class="hlt">heights</span> are crucial for climate forcing calculations. Within the Pan-European Gas-<span class="hlt">Aerosols</span>-climate interaction Study (PEGASOS) the white- light humidified optical particle spectrometer (WHOPS) was developed and installed on the Zeppelin to investigate changes of light scattering with regard to water uptake and altitude. This instrument firstly selects a dry monodisperse <span class="hlt">aerosol</span> by its electrical mobility and then exposes it to a well-defined RH (typically 95%). Alternately, the dry and humidified particles are measured in a white-light optical particle spectrometer (WELAS). In this way it is possible to infer the effective index of refraction of the dry particles, their hygroscopic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992Natur.360..571S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992Natur.360..571S"><span id="translatedtitle">Removal of sulphur from the marine boundary <span class="hlt">layer</span> by ozone oxidation in sea-salt <span class="hlt">aerosols</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sievering, H.; Boatman, J.; Gorman, E.; Kim, Y.; Anderson, L.; Ennis, G.; Luria, M.; Pandis, S.</p> <p>1992-12-01</p> <p>The contribution of ozone oxidation in sea-salt <span class="hlt">aerosols</span> to the cycling of sulfur in the marine boundary <span class="hlt">layer</span> (MBL) is assessed. It is shown that, due to the effects of mass transfer, the non-sea-salt SO4(2-) so generated will be predominantly associated with particles 2-9 microns in diameter and will accordingly dry-deposit at a rapid rate. Because part of the dimethyl sulfide emitted by marine organisms is converted to SO2 in the MBL, this additional removal pathway for sulfur may markedly reduce the proposed feedback between greenhouse warming, oceanic DMS emissions, and sulfate haze albedos.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27441222','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27441222"><span id="translatedtitle">Effect of <span class="hlt">aerosol</span> vertical distribution on <span class="hlt">aerosol</span>-radiation interaction: A theoretical prospect.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mishra, Amit Kumar; Koren, Ilan; Rudich, Yinon</p> <p>2015-10-01</p> <p>This study presents a theoretical investigation of the effect of the <span class="hlt">aerosol</span> vertical distribution on the <span class="hlt">aerosol</span> radiative effect (ARE). Four <span class="hlt">aerosol</span> composition models (dust, polluted dust, pollution and pure scattering <span class="hlt">aerosols</span>) with varying <span class="hlt">aerosol</span> vertical profiles are incorporated into a radiative transfer model. The simulations show interesting spectral dependence of the ARE on the <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span>. ARE increases with the <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span> in the ultraviolet (UV: 0.25-0.42 μm) and thermal-infrared (TH-IR: 4.0-20.0 μm) regions, whereas it decreases in the visible-near infrared (VIS-NIR: 0.42-4.0 μm) region. Changes in the ARE with <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span> are associated with different dominant processes for each spectral region. The combination of molecular (Rayleigh) scattering and <span class="hlt">aerosol</span> absorption is the key process in the UV region, whereas <span class="hlt">aerosol</span> (Mie) scattering and atmospheric gaseous absorption are key players in the VIS-NIR region. The longwave emission fluxes are controlled by the environmental temperature at the <span class="hlt">aerosol</span> <span class="hlt">layer</span> level. ARE shows maximum sensitivity to the <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span> in the TH-IR region, followed by the UV and VIS-NIR regions. These changes are significant even in relatively low <span class="hlt">aerosol</span> loading cases (<span class="hlt">aerosol</span> optical depth ∼0.2-0.3). Dust <span class="hlt">aerosols</span> are the most sensitive to altitude followed by polluted dust and pollution in all three different wavelength regions. Differences in the sensitivity of the <span class="hlt">aerosol</span> type are explained by the relative strength of their spectral absorption/scattering properties. The role of surface reflectivity on the overall altitude dependency is shown to be important in the VIS-NIR and UV regions, whereas it is insensitive in the TH-IR region. Our results indicate that the vertical distribution of water vapor with respect to the <span class="hlt">aerosol</span> <span class="hlt">layer</span> is an important factor in the ARE estimations. Therefore, improved estimations of the water vapor profiles are needed for the further reduction in</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920019991&hterms=eruptions+volcanic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Deruptions%2Bvolcanic','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920019991&hterms=eruptions+volcanic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Deruptions%2Bvolcanic"><span id="translatedtitle">Lidar Observations of Stratospheric <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> After the Mt. Pinatubo Volcanic Eruption</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nagai, Tomohiro; Uchino, Osamu; Fujimoto, Toshifumi</p> <p>1992-01-01</p> <p>The volcano Mt. Pinatubo located on the Luzon Island, Philippines, had explosively erupted on June 15, 1991. The volcanic eruptions such as volcanic ash, SO2 and H2O reached into the stratosphere over 30 km altitude by the NOAA-11 satellite observation and this is considered one of the biggest volcanic eruptions in this century. A grandiose volcanic eruption influences the atmosphere seriously and causes many climatic effects globally. There had been many impacts on radiation, atmospheric temperature and stratospheric ozone after some past volcanic eruptions. The main cause of volcanic influence depends on stratospheric <span class="hlt">aerosol</span>, that stay long enough to change climate and other meteorological conditions. Therefore it is very important to watch stratospheric <span class="hlt">aerosol</span> <span class="hlt">layers</span> carefully and continuously. Standing on this respect, we do not only continue stratospheric <span class="hlt">aerosol</span> observation at Tsukuba but also have urgently developed another lidar observational point at Naha in Okinawa Island. This observational station could be thought valuable since there is no lidar observational station in this latitudinal zone and it is much nearer to Mt. Pinatubo. Especially, there is advantage to link up these two stations on studying the transportation mechanism in the stratosphere. In this paper, we present the results of lidar observations at Tsukuba and Naha by lidar systems with Nd:YAG laser.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1203..585G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1203..585G"><span id="translatedtitle">Remote Monitoring of <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> over Sofia in the Frame of EARLINET-ASOS Project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grigorov, Ivan; Kolarov, Georgi; Stoyanov, Dimitar</p> <p>2010-01-01</p> <p>In this work we present some results of lidar remote sensing of <span class="hlt">aerosol</span> <span class="hlt">layers</span> in the atmosphere in Sofia region. The investigations were made using a lidar system equipped with a CuBr-vapor laser with high pulse repetition of 13 kHz and receiver in photon counting mode. These measurements were performed in frame of the project European <span class="hlt">Aerosol</span> Research Lidar Network—Advanced Sustainable Observation System (EARLINET—ASOS). For some of presented results a conclusion about atmospheric <span class="hlt">aerosol</span>'s origins was made upon analyses of the information about the weather condition during the lidar measurements. Such information was obtained by the weather-forecast maps provided by the Atmospheric Modeling and Weather Forecasting Group of NTUA and the Forecast system of Barcelona Supercomputing Centre and accessible via Internet. Additional information is provided by calculations of the backward air mass trajectories, using online software of NOAA about HYSPLIT model (HYbrid Single-Particle Lagrangian Integrated Trajectory). A common database that automatically collects the data products provided by the individual lidar stations is build and makes data of measurements available to the scientific community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT........98C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT........98C"><span id="translatedtitle">Determination of Planetary Boundary <span class="hlt">Layer</span> <span class="hlt">Height</span> from Ground Based Wind Profiler and Lidar Measurements using the Covariance Wavelet Transform (CWT)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Compton, Jaime Cole</p> <p></p> <p>This thesis documents the application of the Covariance Wavelet Transform (CWT) to lidar and, for the first time to our knowledge, wind profiler data to examine the possibility of accurate and continuous planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> (PBLH) measurements on short temporal resolution (one and fifteen minute averages respectively). Comparisons between PBLHs derived from the Elastic Lidar Facility (ELF) through application of the CWT and daytime radiosonde launches from Beltsville and RFK Stadium as part of the September 2009 NOAA/ARL and NCEP field study show an R2 = 0.84 correlation. PBLHs from ELF aided in diagnosing issues with the automatic PBLH calculation from Aircraft Communications Addressing and Reporting System (ACARS) profiles in the Real-Time Mesoscale Analysis used by plume dispersion modelers. Determining the mixing in the PBL was one goal of a study of the spatial and diurnal variations of the PBL <span class="hlt">height</span> over Maryland for July 2011, during NASA's Earth Venture mission DISCOVER-AQ. A semi-automated PBLH detection algorithm utilizing the CWT for wind profiler data was developed. This algorithm was tested on data from the 915 MHz wind profiler at Beltsville, Maryland, and compared against PBLHs derived from ground based radiosondes measured at Beltsville. Comparisons were also done between PBLHs derived from ground based lidars at UMBC and Beltsville. Results from the comparison show an R 2 = 0.89, 0.92, and 0.94 correlation between the radiosonde PBLHs and the lidars and wind profiler PBLHs, respectively. Accurate determination of the PBLH by applying the CWT to lidar and wind profilers will allow for improved air quality forecasting and understanding of regional pollution dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007AGUFM.A33A0809K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007AGUFM.A33A0809K&link_type=ABSTRACT"><span id="translatedtitle">Resolving Organized <span class="hlt">Aerosol</span> Structures (Rolls and <span class="hlt">Layers</span>) with Airborne Fast Mobility Particle Sizer (FMPS) During MILAGRO/INTEX Campaign</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kapustin, V.; Clarke, A.; Zhou, J.; Howell, S.; Shinozuka, Y.; Brekhovskikh, V.; McNaughton, C.</p> <p>2007-12-01</p> <p>The Hawaii Group for Environmental <span class="hlt">Aerosol</span> Research [http://www.soest.hawaii.edu/HIGEAR] deployed a wide range of <span class="hlt">aerosol</span> instrumentation aboard the C-130 and the NASA DC-8 as part of MILAGRO/INTEX. These were designed to provide rapid information on <span class="hlt">aerosol</span> composition, state of mixing (internal or external), spectral optical properties (scattering and absorption), the humidity dependence of light scattering-f(RH), and the role of condensed species in changing the absorption properties of black carbon (BC) and inferred properties of organic carbon (OC). These measurements included size distributions from about 7 nm up to about 10,000 nm and their volatility at 150, 300 and 400 C; size selected response to heating (volatility) to resolve the state of mixing of the <span class="hlt">aerosol</span>; continuous measurements of the light scattering and absorption at 3 wavelengths; measurements of the f(RH). We also flew the first airborne deployment of the new Fast Mobility Particle Sizer (FMPS, TSI Inc.) that provided information on rapid (1Hz) size variations in the Aitken mode. This revealed small scale structure of the <span class="hlt">aerosol</span> and allowed us to examine size distributions varying over space and time associated with mixing processes previously unresolved etc. Rapid measurements during profiles also revealed variations in size over shallow <span class="hlt">layers</span>. Other dynamic processes included rapid size distribution measurements within orographically induced <span class="hlt">aerosol</span> <span class="hlt">layers</span> and size distribution evolution of the nanoparticles formed by nucleation (C-130 flights 5, 6 and 9). Evidence for fluctuations induced by underlying changes in topography was also detected. These measurements also frequently revealed the <span class="hlt">aerosol</span> variability in the presence of boundary <span class="hlt">layer</span> rolls aligned along the wind in the Marine Boundary <span class="hlt">Layer</span> (Gulf region) both with and without visible cloud streets (DC-8 flight 4 and C-130 flight 7). This organized convection over 1-2 km scales influences the mixing processes (entrainment, RH</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/841474','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/841474"><span id="translatedtitle">The Influence of High <span class="hlt">Aerosol</span> Concentration on Atmospheric Boundary <span class="hlt">Layer</span> Temperature Stratification</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Khaykin, M.N.; Kadygrove, E.N.; Golitsyn, G.S.</p> <p>2005-03-18</p> <p>Investigations of the changing in the atmospheric boundary <span class="hlt">layer</span> (ABL) radiation balance as cased by natural and anthropogenic reasons is an important topic of the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) program. The influence of <span class="hlt">aerosol</span> on temperature stratification of ABL while its concentration was extremely high within a long period of time was studied experimentally. The case was observed in Moscow region (Russia) with the transport of combustion products from peat-bog and forest fires in July-September, 2002. At this time the visibility was some times at about 100-300 m. <span class="hlt">Aerosol</span> concentration measured by Moscow University Observatory and A.M. Obukhov Institute of Atmospheric Physics field station in Zvenigorod (55.7 N; 36.6 E) for several days was in 50-100 times more than background one (Gorchakov at al 2003). The high <span class="hlt">aerosol</span> concentration can change the radiation balance at ABL, and so to change thermal stratification in ABL above the mega lopolis. For the analysis the data were used of synchronous measurements by MTP-5 (Microwave Temperature Profiler operating at wavelength 5 mm) in two locations, namely: downtown Moscow and country-side which is 50 km apart to the West (Zvenigorod station). (Kadygrov and Pick 1998; Westwater at al 1999; Kadygrov at al 2002). Zvenigorod station is located in strongly continental climate zone which is in between of the climates of ARM sites (NSANorth Slope of Alaska and SGP-Southern Great Plains). The town of Zvenigorod has little industry, small traffic volume and topography conductive to a good air ventilation of the town. For these reasons Zvenigorod can be considered as an undisturbed rural site. For the analysis some days were chosen with close meteorological parameters (average temperature, humidity, wind, pressure and cloud form) but strongly differing in <span class="hlt">aerosol</span> concentration level.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860052936&hterms=layers+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlayers%2Bearth','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860052936&hterms=layers+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlayers%2Bearth"><span id="translatedtitle">Observed perturbations of the Earth's Radiation Budget - A response to the El Chichon stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span>?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ardanuy, P. E.; Kyle, H. L.</p> <p>1986-01-01</p> <p>The Earth Radiation Budget experiment, launched aboard the Nimbus-7 polar-orbiting spacecraft in late 1978, has now taken over seven years of measurements. The dataset, which is global in coverage, consists of the individual components of the earth's radiation budget, including longwave emission, net radiation, and both total and near-infrared albedos. Starting some six months after the 1982 eruption of the El Chichon volcano, substantial long-lived positive shortwave irradiance anomalies were observed by the experiment in both the northern and southern polar regions. Analysis of the morphology of this phenomena indicates that the cause is the global stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span> which formed from the cloud of volcanic effluents. There was little change in the emitted longwave in the polar regions. At the north pole the largest anomaly was in the near-infrared, but at the south pole the near UV-visible anomaly was larger. Assuming an exponential decay, the time constant for the north polar, near-infrared anomaly was 1.2 years. At mid- and low latitudes the effect of the El Chichon <span class="hlt">aerosol</span> <span class="hlt">layer</span> could not be separated from the strong reflected-shortwave and emitted-longwave perturbations issuing from the El Nino/Southern Oscillation event of 1982-83.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A23C0238S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A23C0238S"><span id="translatedtitle">Experiments on <span class="hlt">aerosol</span>-induced cooling in the nocturnal boundary <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sreenivas, K.; Singh, D. K.; Vk, P.; Mukund, V.; Subramanian, G.</p> <p>2012-12-01</p> <p>In the nocturnal boundary <span class="hlt">layer</span> (NBL), under calm & clear-sky conditions, radiation is the principal mode of heat transfer & it determines the temperature distribution close to the ground. Radiative processes thus influence the surface energy budget, & play a decisive role in many micro-meteorological processes including the formation of radiation-fog & inversion <span class="hlt">layer</span>. Here, we report hyper-cooling of air <span class="hlt">layers</span> close to the ground that has a radiative origin. Resulting vertical temperature distribution has an anomalous profile with an elevated minimum few decimetres above the ground (known as Lifted Temperature Minimum; LTM). Even though the first observation of this type of profile dates back to 1930s, its origin has not been explained till recently. We report field experiments to elucidate effects of emissivity and other physical properties of the ground on the LTM profile. Field observations clearly indicate that LTM-profiles are observed as a rule in the lowest meter of the NBL. We also demonstrate that the air-<span class="hlt">layer</span> near the ground, rather than the ground itself, leads the post sunset cooling. This fact changes the very nature of the sensible heat-flux boundary condition. A laboratory experimental setup has been developed that can reproduce LTM. Lab-experiments demonstrate that the high cooling rates observed in the field experiments arise from the presence of <span class="hlt">aerosols</span> & the intensity of cooling is proportional to <span class="hlt">aerosol</span> concentration (Fig-1). We have also captured penetrative convection cells in the field experiments (Fig-2). Results presented here thus help in parameterizing transport processes in the NBL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JASTP.104..106S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JASTP.104..106S"><span id="translatedtitle">Global model of the F2 <span class="hlt">layer</span> peak <span class="hlt">height</span> for low solar activity based on GPS radio-occultation data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shubin, V. N.; Karpachev, A. T.; Tsybulya, K. G.</p> <p>2013-11-01</p> <p>We propose a global median model SMF2 (Satellite Model of the F2 <span class="hlt">layer</span>) of the ionospheric F2-<span class="hlt">layer</span> <span class="hlt">height</span> maximum (hmF2), based on GPS radio-occultation data for low solar activity periods (F10.7A<80). The model utilizes data provided by GPS receivers onboard satellites CHAMP (~100,000 hmF2 values), GRACE (~70,000) and COSMIC (~2,000,000). The data were preprocessed to remove cases where the absolute maximum of the electron density lies outside the F2 region. Ground-based ionospheric sounding data were used for comparison and validation. Spatial dependence of hmF2 is modeled by a Legendre-function expansion. Temporal dependence, as a function of Universal Time (UT), is described by a Fourier expansion. Inputs of the model are: geographical coordinates, month and F10.7A solar activity index. The model is designed for quiet geomagnetic conditions (Kр=1-2), typical for low solar activity. SMF2 agrees well with the International Reference Ionosphere model (IRI) in those regions, where the ground-based ionosonde network is dense. Maximal difference between the models is found in the equatorial belt, over the oceans and the polar caps. Standard deviations of the radio-occultation and Digisonde data from the predicted SMF2 median are 10-16 km for all seasons, against 13-29 km for IRI-2012. Average relative deviations are 3-4 times less than for IRI, 3-4% against 9-12%. Therefore, the proposed hmF2 model is more accurate than IRI-2012.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRD..116.2205N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRD..116.2205N"><span id="translatedtitle">Sensitivity of nocturnal boundary <span class="hlt">layer</span> temperature to tropospheric <span class="hlt">aerosol</span> surface radiative forcing under clear-sky conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nair, Udaysankar S.; McNider, Richard; Patadia, Falguni; Christopher, Sundar A.; Fuller, Kirk</p> <p>2011-01-01</p> <p>Since the middle of the last century, global surface air temperature exhibits an increasing trend, with nocturnal temperatures increasing at a much higher rate. Proposed causative mechanisms include the radiative impact of atmospheric <span class="hlt">aerosols</span> on the nocturnal boundary <span class="hlt">layer</span> (NBL) where the temperature response is amplified due to shallow depth and its sensitivity to potential destabilization. A 1-D version of the Regional Atmospheric Modeling System is used to examine the sensitivity of the nocturnal boundary <span class="hlt">layer</span> temperature to the surface longwave radiative forcing (SLWRF) from urban <span class="hlt">aerosol</span> loading and doubled atmospheric carbon dioxide concentrations. The analysis is conducted for typical midlatitude nocturnal boundary <span class="hlt">layer</span> case days from the CASES-99 field experiment and is further extended to urban sites in Pune and New Delhi, India. For the cases studied, locally, the nocturnal SLWRF from urban atmospheric <span class="hlt">aerosols</span> (2.7-47 W m-2) is comparable or exceeds that caused by doubled atmospheric carbon dioxide (3 W m-2), with the surface temperature response ranging from a compensation for daytime cooling to an increase in the nocturnal minimum temperature. The sensitivity of the NBL to radiative forcing is approximately 4 times higher compared to the daytime boundary <span class="hlt">layer</span>. Nighttime warming or cooling may occur depending on the nature of diurnal variations in <span class="hlt">aerosol</span> optical depth. Soil moisture also modulates the magnitude of SLWRF, decreasing from 3 to 1 W m-2 when soil saturation increases from 37% to 70%. These results show the importance of <span class="hlt">aerosols</span> on the radiative balance of the climate system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JGRD..11110309X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JGRD..11110309X"><span id="translatedtitle">Summertime <span class="hlt">aerosol</span> chemical components in the marine boundary <span class="hlt">layer</span> of the Arctic Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Zhouqing; Sun, Liguang; Blum, Joel D.; Huang, Yuying; He, Wei</p> <p>2006-05-01</p> <p>Samples of <span class="hlt">aerosols</span> from the marine boundary <span class="hlt">layer</span> of the Arctic Ocean were collected aboard the R/V Xuelong during summer on the Second Chinese Arctic Research Expedition (July-September 2003). Synchrotron radiation X-ray fluorescence (SR-XRF) was used to determine chemical compositions of <span class="hlt">aerosol</span> particles. Multivariate analysis of the SR-XRF data resolved a number of components (factors), which, on the basis of their chemical compositions and from their affiliation with specific meteorological flow patterns, were assigned physical meanings. Five factors explaining 94.7% of the total variance were identified. Ship emissions accounted for 35.3% of the variance (factor 1 (F1)) and are loaded significantly with S, Fe, V, and Ni. The total Fe emitted from ships globally was estimated at 8.60 × 106 kg yr-1. Heavy-metal-rich factors included 34.0% of the variance (F2 and F3) and were interpreted to be pollution carried into the Arctic Ocean by long-range transport. Anthropogenic contributions from industrial regions to the Arctic Ocean during the summer vary and depend on the source locations. Air mass backward trajectories indicate that the metals including Hg, Pb, Cu, and Zn come mainly from northern Russia. The third source controlling the chemical compositions of <span class="hlt">aerosols</span> was sea salt (F4, 12.8%). The role of sea salt decreased from the open sea to areas near pack ice. On the basis of the factor scores of <span class="hlt">aerosol</span> samples, we infer that chlorine volatilization from sea salt may occur, enhanced by nitrogen and sulfur contamination emitted from ships. Because the global inventories of nitrogen and sulfur for ship exhausts are large, and halogens could have important consequences in possible tropospheric ozone destruction, the role of ships in influencing halogen depression in sea salt should be further investigated. Finally, we also identified a crustal factor (F5, 12.6%) and suggest that crustal elements (e.g., Ca) contaminating sea ice may become reinjected into</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090026581','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090026581"><span id="translatedtitle">Extinction-to-Backscatter Ratios of Lofted <span class="hlt">Aerosol</span> <span class="hlt">Layers</span> Observed During the First Three Months of CALIPSO Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Omar, Ali H.; Vaughan, Mark A.; Liu, Zhaoyan; Hu, Yongxiang; Reagan, John A.; Winker, David M.</p> <p>2007-01-01</p> <p>Case studies from the first three months of the Cloud and <span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Spaceborne Observations (CALIPSO) measurements of lofted <span class="hlt">aerosol</span> <span class="hlt">layers</span> are analyzed using transmittance [Young, 1995] and two-wavelength algorithms [Vaughan et al., 2004] to determine the <span class="hlt">aerosol</span> extinction-to-backscatter ratios at 532 and 1064 nm. The transmittance method requires clear air below the <span class="hlt">layer</span> so that the transmittance through the <span class="hlt">layer</span> can be determined. Suitable scenes are selected from the browse images and clear air below features is identified by low 532 nm backscatter signal and confirmed by low depolarization and color ratios. The transmittance and two-wavelength techniques are applied to a number of lofted <span class="hlt">layers</span> and the extinction-to-backscatter ratios are compared with values obtained from the CALIPSO <span class="hlt">aerosol</span> models [Omar et al., 2004]. The results obtained from these studies are used to adjust the <span class="hlt">aerosol</span> models and develop observations based extinction-to-backscatter ratio look-up tables and phase functions. Values obtained by these techniques are compared to Sa determinations using other independent methods with a goal of developing probability distribution functions of <span class="hlt">aerosol</span> type-specific extinction to backscatter ratios. In particular, the results are compared to values determined directly by the High Spectral Resolution Lidar (HSRL) during the CALIPSO CloudSat Validation Experiments (CCVEX) and Sa determined by the application of the two-wavelength lidar Constrained Ratio <span class="hlt">Aerosol</span> Model-fit (CRAM) retrieval approach [Cattrall et al., 2005; Reagan et al., 2004] to the HSRL data. The results are also compared to values derived using the empirical relationship between the multiple-scattering fraction and the linear depolarization ratio by using Monte Carlo simulations of water clouds [Hu et al., 2006].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993PhDT.......144H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993PhDT.......144H"><span id="translatedtitle">Electromagnetic Wave Scattering by AN Infinitely Long Conducting Circular Cylinder Covered with <span class="hlt">Layers</span> of Lossy Material of Finite <span class="hlt">Height</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heidary Bigvand, Kaveh</p> <p></p> <p>Three-dimensional electromagnetic (EM) wave scattering by an infinitely long perfectly conducting circular cylinder clad partially with <span class="hlt">layers</span> of lossy material of finite <span class="hlt">height</span> is studied. The scattering problem is solved via two distinct mathematical formulations. Modal and hybrid formulations are founded, respectively, on the modal theory of electromagnetics and geometrical optics (GO) in conjunction with the moment method. Both formulations lead to solutions for EM fields inside the material <span class="hlt">layers</span> which are subsequently used to compute other parameters of interest. The modal technique is based on formulating EM fields inside each material coating in terms of a transverse magnetic (to cylinder axis) and a transverse electric potential function. Each potential function is expressed in terms of a superposition of elementary wave functions with unknown coefficients (mode amplitudes). The equivalence principle is applied to replace each material coating with induced polarization (electric) and/or magnetization (magnetic) current densities. Material-scattered fields, which denote EM fields radiated by induced current sources in the presence of the conducting core, are formulated in terms of unknown mode amplitudes. Three dimensional problems, encountered in formulation of the material-scattered fields, are solved by utilizing Fourier transformations with respect to the cylinder axis. At the outer surface of the outermost <span class="hlt">layer</span> the sum of generator (EM fields in the absence of the coating) and material-scattered fields are set equal to total EM fields. Employing an appropriate inner product and relevant testing functions one reduces these equations to a set of systems of linear algebraic equations, which are solved for mode amplitudes. The hybrid technique applies the equivalence principle in combination with a dyadic Green's function to cast the electromagnetic problem into that of an integral equation for interior EM fields. Green's function derivation is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22261872','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22261872"><span id="translatedtitle">Surface barrier <span class="hlt">height</span> for different Al compositions and barrier <span class="hlt">layer</span> thicknesses in AlGaN/GaN heterostructure field effect transistors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Goyal, Nitin Fjeldly, Tor A.; Iniguez, Benjamin</p> <p>2013-12-04</p> <p>In this paper, we present a physics based analytical model for the calculation of surface barrier <span class="hlt">height</span> for given values of barrier <span class="hlt">layer</span> thicknesses and Al mole fractions. An explicit expression for the two dimensional electron gas density is also developed incorporating the change in polarization charges for different Al mole fractions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7207256','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7207256"><span id="translatedtitle">Airship measurements of <span class="hlt">aerosol</span> size distributions, cloud droplet spectra, and trace gas concentrations in the marine boundary <span class="hlt">layers</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Frick, G.M.; Hoppel, W.A. )</p> <p>1993-11-01</p> <p>The use of an airship as a platform to conduct atmospheric chemistry, <span class="hlt">aerosol</span>, and cloud microphysical research is described, and results from demonstration flights made off the Oregon coast are presented. The slow speed of the airship makes it an ideal platform to do high-spatial resolution profiling both vertically and horizontally, and to measure large <span class="hlt">aerosol</span> and cloud droplet distributions without the difficulties caused by high-speed aircraft sampling. A unique set of data obtained during the demonstration flights show the effect that processing marine boundary <span class="hlt">layer</span> <span class="hlt">aerosol</span> through stratus clouds has on the <span class="hlt">aerosol</span> size distribution. Evidence of new particle formation (nucleation of particles) was also observed on about half the days on which flights were made. 11 refs., 9 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PApGe.171.2425P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PApGe.171.2425P"><span id="translatedtitle"><span class="hlt">Aerosol</span> Measurements in the Atmospheric Surface <span class="hlt">Layer</span> at L'Aquila, Italy: Focus on Biogenic Primary Particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pitari, Giovanni; Coppari, Eleonora; De Luca, Natalia; Di Carlo, Piero; Pace, Loretta</p> <p>2014-09-01</p> <p>Two year measurements of <span class="hlt">aerosol</span> concentration and size distribution (0.25 μm < d < 30 μm) in the atmospheric surface <span class="hlt">layer</span>, collected in L'Aquila (Italy) with an optical particle counter, are reported and analysed for the different modes of the particle size distribution. A different seasonal behaviour is shown for fine mode <span class="hlt">aerosols</span> (largely produced by anthropogenic combustion), coarse mode and large-sized <span class="hlt">aerosols</span>, whose abundance is regulated not only by anthropogenic local production, but also by remote natural sources (via large scale atmospheric transport) and by local sources of primary biogenic <span class="hlt">aerosols</span>. The observed total abundance of large particles with diameter larger than 10 μm is compared with a statistical counting of primary biogenic particles, made with an independent technique. Results of these two observational approaches are analysed and compared to each other, with the help of a box model driven by observed meteorological parameters and validated with measurements of fine and coarse mode <span class="hlt">aerosols</span> and of an atmospheric primary pollutant of anthropogenic origin (NOx). Except in winter months, primary biogenic particles in the L'Aquila measurement site are shown to dominate the atmospheric boundary <span class="hlt">layer</span> population of large <span class="hlt">aerosol</span> particles with diameter larger than 10 μm (about 80 % of the total during summer months), with a pronounced seasonal cycle, contrary to fine mode <span class="hlt">aerosols</span> of anthropogenic origin. In order to explain these findings, the main mechanisms controlling the abundance and variability of particulate matter tracers in the atmospheric surface <span class="hlt">layer</span> are analysed with the numerical box-model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JQSRT.176...34O&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JQSRT.176...34O&link_type=ABSTRACT"><span id="translatedtitle">Elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> modify the O2-O2 absorption measured by ground-based MAX-DOAS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ortega, Ivan; Berg, Larry K.; Ferrare, Richard A.; Hair, Johnathan W.; Hostetler, Chris A.; Volkamer, Rainer</p> <p>2016-06-01</p> <p>The oxygen collisional complex (O2-O2, or O4) is a greenhouse gas, and a calibration trace gas used to infer <span class="hlt">aerosol</span> and cloud properties by Differential Optical Absorption Spectroscopy (DOAS). Recent reports suggest the need for an O4 correction factor (CFO4) when comparing simulated and measured O4 differential slant column densities (dSCD) by passive DOAS. We investigate the sensitivity of O4 dSCD simulations at ultraviolet (360 nm) and visible (477 nm) wavelengths towards separately measured <span class="hlt">aerosol</span> extinction profiles. Measurements were conducted by the University of Colorado 2D-MAX-DOAS instrument and NASA's multispectral High Spectral Resolution Lidar (HSRL-2) during the Two Column <span class="hlt">Aerosol</span> Project (TCAP) at Cape Cod, MA in July 2012. During two case study days with (1) high <span class="hlt">aerosol</span> load (17 July, AOD~0.35 at 477 nm), and (2) near molecular scattering conditions (22 July, AOD<0.10 at 477 nm) the measured and calculated O4 dSCDs agreed within 6.4±0.4% (360 nm) and 4.7±0.6% (477 nm) if the HSRL-2 profiles were used as input to the calculations. However, if in the calculations the <span class="hlt">aerosol</span> is confined to the surface <span class="hlt">layer</span> (while keeping AOD constant) we find 0.53<CFO4<0.75, similar to previously reported CFO4. Our results suggest that elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span>, unless accounted for, can cause negative bias in the simulated O4 dSCDs that can explain CFO4. The air density and <span class="hlt">aerosol</span> profile aloft needs to be taken into account when interpreting the O4 from ground-based MAX-DOAS. Opportunities to identify and better characterize these elevated <span class="hlt">layers</span> are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JASTP.104..116A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JASTP.104..116A"><span id="translatedtitle">Black carbon <span class="hlt">aerosols</span> in a tropical semi-urban coastal environment: Effects of boundary <span class="hlt">layer</span> dynamics and long range transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aruna, K.; Kumar, T. V. Lakshmi; Rao, D. Narayana; Murthy, B. V. Krishna; Babu, S. Suresh; Moorthy, K. Krishna</p> <p>2013-11-01</p> <p>Regular measurements of Black Carbon (BC) <span class="hlt">aerosol</span> mass concentration have been carried out since March 2011 at a tropical location (12.81°N, 80.03°E) adjoining the mega city, Chennai, on the east coast of India for the first time. As this region is influenced by both the South West and North East monsoons, the BC observations at this site assume importance in understanding the overall BC distribution over India. The data collected until August 2012 has been examined for the general and regionally distinctive features. Spectral absorption characteristics reveal that the BC is mainly from fossil fuel based emissions. The BC concentration shows significant diurnal variation only in the North East monsoon and winter seasons with night time concentration considerably higher than the day time concentration. In the other seasons the day-night contrast in BC is not significant. Seasonal variation is rather subdued with a broad maximum during the Northeast monsoon and winter months and a minimum during the southwest monsoon months. The observed diurnal and seasonal variations are examined in the light of local Atmospheric Boundary <span class="hlt">Layer</span> dynamics and long range transport. For the first time, an inverse relationship has been established between BC and ABL <span class="hlt">height</span> on a quantitative basis. A distinctive feature of the region is that in all the seasons transport pathways have long continental overpasses which could lead to the suppressed seasonal variation. It is found that the BC over this region shows distinct diurnal and seasonal features compared to those reported for other coastal and inland regions in India.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A53B0375R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A53B0375R"><span id="translatedtitle">Radiative Impact of <span class="hlt">Aerosols</span> on the Regional Boundary <span class="hlt">Layer</span> Features in Strong and Weak Wind Conditions using WRF Modeling System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rajagopalan, R. A.; Sharan, M.</p> <p>2015-12-01</p> <p>Atmospheric <span class="hlt">aerosol</span> particles play a vital role in the Earth's radiative energy budget. They exert a net cooling influence on climate by directly reflecting the solar radiation to space and by modifying the shortwave reflective properties of clouds. Radiation is the main source that regulates the surface energy budget. Surface temperature and planetary boundary <span class="hlt">layer</span> (PBL) <span class="hlt">height</span> depends on accurate calculation of both shortwave and longwave radiation. The weakening of the ambient winds is known to influence the structure of PBL. This study examines the sensitivity of the performance of Weather Research Forecasting (WRF) ARW Model to the use of different radiation schemes [For Long wave Radiation: Rapid Radiative Transfer Model (RRTM), Eta Geophysical Fluid Dynamics Laboratory (GFDL), Goddard, New Goddard, NCAR Community Atmosphere Model (CAM 3.0), New Goddard scheme, Fu-Liou-Gu scheme and for Short wave Radiation: Dudhia scheme, Eta Geophysical Fluid Dynamics Laboratory (GFDL), NCAR Community Atmosphere Model (CAM 3.0), New Goddard scheme]. Two different simulations are conducted one for the summer (14-15 May 2009) and winter (14-15 Dec 2008) season characterized by strong and weak wind conditions over India. Comparison of surface temperatures from different schemes for different cities (New Delhi, Ahmedabad, Lucknow, Kanpur, Jaipur and Jodhpur) on 14-15 May 2009 and 14-15 Dec 2008 with those observed shows the simulation with RRTM , New Goddard, and Fu-Liou-Gu schemes are closer to the observations as compared to other schemes. The temperature simulated from all the radiation schemes have more than 0.9 correlation coefficient but the root mean square error is relatively less in summer compared to winter season. It is surmised that Fu-Liou-Gu scheme performs better in almost all the cases. The reason behind can be the greater absorption of solar and IR radiative fluxes in the atmosphere and the surface provided in Fu-Liou-Gu radiation scheme than those computed in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A54B..05Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A54B..05Z"><span id="translatedtitle">The relationship of boundary <span class="hlt">layer</span> clouds in the tropical southeast Atlantic to absorbing <span class="hlt">aerosols</span>, meteorology and climate change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zuidema, P.; Adebiyi, A. A.; Ramajiguru, L.</p> <p>2015-12-01</p> <p>Ascension Island, a remote island located in the middle of the Atlantic Ocean within the trade-wind region oat 8S, 14.5W, experiences the outflow of biomass-burning <span class="hlt">aerosols</span> from continental Africa, over 2000 km away, from July through November, peaking in August and September. The shortwave-absorbing free-tropospheric <span class="hlt">aerosols</span>, located in a region of high solar irradiance, provide a climate warming that is poorly represented in global <span class="hlt">aerosol</span> climate models. The low clouds can respond to the smoke <span class="hlt">layer</span> in myriad possible ways that are not yet well-documented. The shortwave-warming can stabilize the free-troposphere, enhancing the low cloud fraction. The deepening boundary <span class="hlt">layer</span> and subsiding smoke <span class="hlt">layer</span> also increase the likelihood of <span class="hlt">aerosol</span>-cloud microphysical interactions. Interest in this climate regime is supporting an observational strategy of a year-long DOE ARM Mobile Facility deployment to Ascension (<span class="hlt">Layered</span> Atlantic Smoke Interactions with Clouds, or LASIC), and an NSF aircraft campaign (ObservatioNs of Fireʼs Impact on the southeast atlantic REgion, or ONFIRE) based on Sao Tome Island. These campaigns will be integrated with NASA, UK and African activities sharing similar goals based further south in Namibia. Initial analysis is distinguishing meteorology from <span class="hlt">aerosol</span> impacts on the boundary <span class="hlt">layer</span> cloud fields. The forward trajectories of emissions from over 24,000 fire sources on continental Africa show that a free-tropospheric jet can advect <span class="hlt">aerosols</span> to above Ascension island in just one-two days. The fast transport time encourages retention of signatures of the fire sources, in particular the radiatively-crucial single-scattering albedo value. Thereafter, a deep land-based anticyclonic high recirculates over one-third of these trajectories back to the African continent, explaining the widespread extent of the <span class="hlt">aerosol</span> <span class="hlt">layer</span>. The free-tropospheric jet also reduces the mean atmospheric subsidence independently of shortwave absorption by the <span class="hlt">aerosols</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20531786','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20531786"><span id="translatedtitle">Lidar determination of winds by <span class="hlt">aerosol</span> inhomogeneities: motion velocity in the planetary boundary <span class="hlt">layer</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kolev, I; Parvanov, O; Kaprielov, B</p> <p>1988-06-15</p> <p>The paper presents results from lidar measurements of wind velocity in the planetary boundary <span class="hlt">layer</span> using correlation data processing. Two lidars are used in our experiments: a ruby lidar operating along slant paths and a YAG:Nd lidar operating for near vertical sounding used by us for the first time. On the basis of our experience the optimal sizes of <span class="hlt">aerosol</span> inhomogeneities (30-300 m), the duration of the experiments (2-10 min), and the repetition rate of laser shots (fractions of hertz to several hertz) are determined. The results are compared to independent data obtained from anemometer measurements, theodolite- and radar-tracked pilot balloons. The range of differences is ~1-2 m/s in speed and 10-15 degrees in direction. Preliminary results from the use of lidar data to remotely sound the wind speed for various atmospheric stratifications and synoptic situations are described as well. PMID:20531786</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008PhDT........54C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008PhDT........54C&link_type=ABSTRACT"><span id="translatedtitle">Secondary organic <span class="hlt">aerosol</span> formation of relevance to the marine boundary <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cai, Xuyi</p> <p></p> <p>The chlorine atom (Cl) is a potential oxidant of volatile organic compounds (VOCs) in the atmosphere and is hypothesized to lead to secondary organic <span class="hlt">aerosol</span> (SOA) formation in coastal areas. The purpose of this dissertation is to test this hypothesis and quantify the SOA formation potentials of some representative biogenic and anthropogenic hydrocarbons when oxidized by Cl in laboratory chamber experiments. The chosen model compounds for biogenic and anthropogenic hydrocarbons in this study are three monoterpenes (alpha-pinene, beta-pinene, and d-limonene) and two aromatics (m-xylene and toluene), respectively. Results indicate that the oxidation of these monoterpenes and aromatics generates significant amounts of <span class="hlt">aerosol</span>. The SOA yields of alpha-pinene, beta-pinene, and d-limonene obtained in this study are comparable to those when they are oxidized by ozone, by nitrate radical, and in photooxidation scenarios. For <span class="hlt">aerosol</span> mass up to 30.0 mug m-3, their yields reach approximately 0.20, 0.20, and 0.30, respectively. The SOA yields for m-xylene and toluene are found to be in the range of 0.035 to 0.12 for <span class="hlt">aerosol</span> concentrations up to 19 mug m-3. For d-limonene and toluene, data indicate two yield curves that depend on the initial concentration ratios of Cl precursor to hydrocarbon hydrocarbon. Zero-dimensional calculations based on these yields show that SOA formation from the five model compounds when oxidized by Cl in the marine boundary <span class="hlt">layer</span> could be a significant source of SOA in the early morning. In addition, the mechanistic reaction pathways for Cl oxidation of alpha-pinene, beta-pinene, d-limonene, and toluene with Cl have been developed within the framework of the Caltech Atmospheric Chemistry Mechanisms (CACM). Output from the developed mechanisms is combined with an absorptive partitioning model to predict precursor decay curves and time-dependent SOA concentrations in experiments. Model calculations are able to match (in general within general +/- 50</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140013033','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140013033"><span id="translatedtitle">Improvements to the OMI Near-uv <span class="hlt">Aerosol</span> Algorithm Using A-train CALIOP and AIRS Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Torres, O.; Ahn, C.; Zhong, C.</p> <p>2014-01-01</p> <p>The <span class="hlt">height</span> of desert dust and carbonaceous <span class="hlt">aerosols</span> <span class="hlt">layers</span> and, to a lesser extent, the difficulty in assessing the predominant size mode of these absorbing <span class="hlt">aerosol</span> types, are sources of uncertainty in the retrieval of <span class="hlt">aerosol</span> properties from near UV satellite observations. The availability of independent, near-simultaneous measurements of <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span>, and <span class="hlt">aerosol</span>-type related parameters derived from observations by other A-train sensors, makes possible the direct use of these parameters as input to the OMI (Ozone Monitoring Instrument) near UV retrieval algorithm. A monthly climatology of <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span> derived from observations by the CALIOP (Cloud-<span class="hlt">Aerosol</span> Lidar with Orthogonal Polarization) sensor, and real-time AIRS (Atmospheric Infrared Sounder) CO observations are used in an upgraded version of the OMI near UV <span class="hlt">aerosol</span> algorithm. AIRS CO measurements are used as a reliable tracer of carbonaceous <span class="hlt">aerosols</span>, which allows the identification of smoke <span class="hlt">layers</span> in areas and times of the year where the dust-smoke differentiation is difficult in the near-UV. The use of CO measurements also enables the identification of elevated levels of boundary <span class="hlt">layer</span> pollution undetectable by near UV observations alone. In this paper we discuss the combined use of OMI, CALIOP and AIRS observations for the characterization of <span class="hlt">aerosol</span> properties, and show a significant improvement in OMI <span class="hlt">aerosol</span> retrieval capabilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A51O..03H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A51O..03H"><span id="translatedtitle">One Year of Doppler Lidar Observations Characterizing Boundary <span class="hlt">Layer</span> Wind, Turbulence, and <span class="hlt">Aerosol</span> Structure During the Indianapolis Flux Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hardesty, R. M.; Brewer, A.; Shepson, P. B.; Cambaliza, M. O. L.; Salmon, O. E.; Heimburger, A. M. F.; Davis, K. J.; Lauvaux, T.; McGowan, L. E.; Miles, N. L.; Richardson, S.; Sarmiento, D. P.; Karion, A.; Sweeney, C.; Iraci, L. T.; Hillyard, P. W.; Podolske, J. R.; Gurney, K. R.; Razlivanov, I. N.; Song, Y.; Turnbull, J. C.; Whetstone, J. R.; Possolo, A.; Prasad, K.</p> <p>2014-12-01</p> <p>The Indianapolis Flux Experiment (INFLUX) is aimed at improving methods for estimation of greenhouse gas emissions at urban scales. INFLUX observational components include several-times-per-month aircraft measurements of gas concentrations and meteorological parameters, as well as a number of towers observing CO2, CH4, and CO and a single continuously operating Doppler lidar to estimate wind, turbulence and <span class="hlt">aerosol</span> structure in the boundary <span class="hlt">layer</span>. The observations are used to develop top-down emissions estimates from the aircraft measurements and as input to inversion models. The Doppler lidar provides information on boundary <span class="hlt">layer</span> structure for both the aircraft and inversion studies. A commercial Doppler lidar characterized by low pulse energy and high pulse repetition rate has operated for well over a year at a site NE of downtown Indianapolis. The lidar produces profiles of horizontal wind speed, vertical velocity variance, and <span class="hlt">aerosol</span> structure two to three times per hour. These data are then used to investigate boundary <span class="hlt">layer</span> mixing and thickness and horizontal transport as inputs for the flux calculations. During its one year deployment the lidar generally operated reliably with few outages. Comparisons with aircraft spirals over the site and with the NOAA High Resolution research Doppler lidar deployed to Indianapolis for one month during May, 2014, were used to assess the performance of the INFLUX lidar. Measurements agreed quite well when <span class="hlt">aerosol</span> loading was sufficient for lidar observations throughout the boundary <span class="hlt">layer</span>. However, low <span class="hlt">aerosol</span> loading during some periods limited the range of the lidar and precluded characterization of the full boundary <span class="hlt">layer</span>. We present an overall assessment of the commercial Doppler lidar for providing the needed information on boundary <span class="hlt">layer</span> structure for emission estimations, and show variability of the boundary <span class="hlt">layer</span> observations over diurnal, seasonal, and annual cycles. Recommendations on system design changes to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830034721&hterms=layers+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlayers%2Bearth','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830034721&hterms=layers+earth&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlayers%2Bearth"><span id="translatedtitle">A simple method to compute the change in earth-atmosphere radiative balance due to a stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lenoble, J.; Tanre, D.; Deschamps, P. Y.; Herman, M.</p> <p>1982-01-01</p> <p>A computer code was developed in terms of a three-<span class="hlt">layer</span> model for the earth-atmosphere system, using a two-stream approximation for the troposphere and stratosphere. The analysis was limited to variable atmosphere loading by solar radiation over an unperturbed section of the atmosphere. The scattering atmosphere above a Lambertian ground <span class="hlt">layer</span> was considered in order to derive the planar albedo and the spherical albedo. Attention was given to the influence of the <span class="hlt">aerosol</span> optical thickness in the stratosphere, the single scattering albedo and asymmetry factor, and the sublayer albedo. Calculations were performed of the zonal albedo and the planetary radiation balance, taking into account a stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span> containing H2SO4 droplets and volcanic ash. The resulting ground temperature disturbance was computed using a Budyko (1969) climate model. Local decreases in the albedo in the summer were observed in high latitudes, implying a heating effect of the <span class="hlt">aerosol</span>. An accompanying energy loss of 23-27 W/sq m was projected, which translates to surface temperature decreases of either 1.1 and 0.45 C, respectively, for background and volcanic <span class="hlt">aerosols</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...618998P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...618998P"><span id="translatedtitle">Enhanced air pollution via <span class="hlt">aerosol</span>-boundary <span class="hlt">layer</span> feedback in China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petäjä, T.; Järvi, L.; Kerminen, V.-M.; Ding, A. J.; Sun, J. N.; Nie, W.; Kujansuu, J.; Virkkula, A.; Yang, X.; Fu, C. B.; Zilitinkevich, S.; Kulmala, M.</p> <p>2016-01-01</p> <p>Severe air pollution episodes have been frequent in China during the recent years. While high emissions are the primary reason for increasing pollutant concentrations, the ultimate cause for the most severe pollution episodes has remained unclear. Here we show that a high concentration of particulate matter (PM) will enhance the stability of an urban boundary <span class="hlt">layer</span>, which in turn decreases the boundary <span class="hlt">layer</span> <span class="hlt">height</span> and consequently cause further increases in PM concentrations. We estimate the strength of this positive feedback mechanism by combining a new theoretical framework with ambient observations. We show that the feedback remains moderate at fine PM concentrations lower than about 200 μg m-3, but that it becomes increasingly effective at higher PM loadings resulting from the combined effect of high surface PM emissions and massive secondary PM production within the boundary <span class="hlt">layer</span>. Our analysis explains why air pollution episodes are particularly serious and severe in megacities and during the days when synoptic weather conditions stay constant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4709519','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4709519"><span id="translatedtitle">Enhanced air pollution via <span class="hlt">aerosol</span>-boundary <span class="hlt">layer</span> feedback in China</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Petäjä, T.; Järvi, L.; Kerminen, V.-M.; Ding, A.J.; Sun, J.N.; Nie, W.; Kujansuu, J.; Virkkula, A.; Yang, X.; Fu, C.B.; Zilitinkevich, S.; Kulmala, M.</p> <p>2016-01-01</p> <p>Severe air pollution episodes have been frequent in China during the recent years. While high emissions are the primary reason for increasing pollutant concentrations, the ultimate cause for the most severe pollution episodes has remained unclear. Here we show that a high concentration of particulate matter (PM) will enhance the stability of an urban boundary <span class="hlt">layer</span>, which in turn decreases the boundary <span class="hlt">layer</span> <span class="hlt">height</span> and consequently cause further increases in PM concentrations. We estimate the strength of this positive feedback mechanism by combining a new theoretical framework with ambient observations. We show that the feedback remains moderate at fine PM concentrations lower than about 200 μg m−3, but that it becomes increasingly effective at higher PM loadings resulting from the combined effect of high surface PM emissions and massive secondary PM production within the boundary <span class="hlt">layer</span>. Our analysis explains why air pollution episodes are particularly serious and severe in megacities and during the days when synoptic weather conditions stay constant. PMID:26753788</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.4927F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.4927F&link_type=ABSTRACT"><span id="translatedtitle">The impact of monthly variation of the Pacific-North America (PNA) teleconnection pattern on wintertime surface-<span class="hlt">layer</span> <span class="hlt">aerosol</span> concentrations in the United States</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feng, Jin; Liao, Hong; Li, Jianping</p> <p>2016-04-01</p> <p>The Pacific-North America teleconnection (PNA) is the leading general circulation pattern in the troposphere over the region of North Pacific to North America during wintertime. This study examined the impacts of monthly variations of the PNA phase (positive or negative phase) on wintertime surface-<span class="hlt">layer</span> <span class="hlt">aerosol</span> concentrations in the United States (US) by analyzing observations during 1999-2013 from the Air Quality System of the Environmental Protection Agency (EPA-AQS) and the model results for 1986-2006 from the global three-dimensional Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). The composite analyses on the EPA-AQS observations over 1999-2013 showed that the average concentrations of PM2.5, sulfate, nitrate, ammonium, organic carbon, and black carbon <span class="hlt">aerosols</span> over the US were higher in the PNA positive phases (25 % of the winter months examined, and this fraction of months had the highest positive PNA index values) than in the PNA negative phases (25 % of the winter months examined, and this fraction of months had the highest negative PNA index values) by 1.0 µg m-3 (8.7 %), 0.01 µg m-3 (0.5 %), 0.3 µg m-3 (29.1 %), 0.1 µg m-3 (11.9 %), 0.6 µg m-3 (13.5 %), and 0.2 µg m-3 (27.8 %), respectively. The simulated geographical patterns of the differences in concentrations of all <span class="hlt">aerosol</span> species between the PNA positive and negative phases were similar to observations. Based on the GEOS-Chem simulation, the pattern correlation coefficients were calculated to show the impacts of PNA-induced variations in meteorological fields on <span class="hlt">aerosol</span> concentrations. The PNA phase was found (i) to influence sulfate concentrations mainly through changes in planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> (PBLH), precipitation (PR), and temperature; (ii) to influence nitrate concentrations mainly through changes in temperature; and (iii) to influence concentrations of ammonium, organic carbon, and black carbon mainly through changes in PR and PBLH. Results from</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1707S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1707S"><span id="translatedtitle">Variability of Atmospheric Boundary <span class="hlt">Layer</span> <span class="hlt">height</span> over the tropical oceans - A study using atmospheric refractivity profiles from multi campaign in-situ and satellite radio occultation data.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Santosh, M.</p> <p>2016-07-01</p> <p>Atmospheric Boundary <span class="hlt">Layer</span> (ABL) over the tropical oceans controls and regulates the influx of water vapour into the free atmosphere due to evaporation. The availability of in situ data for determining the ABL characteristics over tropical oceans are limited to different ship based campaigns and hence restricted in spatial and temporal coverage. For ABL studies the Radio Occultation (RO) based satellite data over tropical oceans have good temporal and spatial coverage but limited in temporal and spatial resolution. Atmospheric refractivity profiles are extensively used in many studies to determine the ABL <span class="hlt">height</span> from both platforms. The present study attempts to use the advantages in both in-situ and satellite (RO) based data to quantify the variability in the ABL <span class="hlt">height</span> over the tropical oceans. All studies done so far to identify the ABL <span class="hlt">height</span> from RO derived refractivity profiles rely extensively on the detection of the minimum refractivity gradient (MRG) below ~6 km along with additional threshold criteria. This leads to an over estimation of ABL <span class="hlt">heights</span> especially in presence of strong subsidence inversion caused by local/ mesoscale/ synoptic scale processes where the MRG lies significantly above the ABL. The present study attempts to quantify this over estimation using atmospheric refractivity profiles derived from thermo-dynamical parameters from radiosonde ascents over the tropical ocean, suggests an improved method of ABL detection and quantifies the variability so deduced. Over 1000 radiosonde ascents from four ship cruises conducted during DYNAMO 2011 field campaign over the tropical Indian Ocean are used for the purpose. ABL <span class="hlt">heights</span> determined from radiosonde data using traditional methods (using virtual potential temperature and specific humidity) are compared with those identified from simulated atmospheric refractivity profiles from same data (using prevalent methods for RO) to quantify the over estimation. A new method of ABL detection from</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhD...49y5302S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhD...49y5302S"><span id="translatedtitle">Precise control of Schottky barrier <span class="hlt">height</span> in SrTiO3/SrRuO3 heterojunctions using ultrathin interface polar <span class="hlt">layers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sampath Kumar, V.; Niranjan, Manish K.</p> <p>2016-06-01</p> <p>Control of Schottky barrier <span class="hlt">height</span> using a polar interface <span class="hlt">layer</span> at oxide heterointerfaces offers interesting and promising applications in oxide-based electronics. Using ab initio density functional theory, the Schottky barrier <span class="hlt">heights</span> are determined in SrRuO3 /SrTiO3(0 0 1) heterojunctions with interfacial polar <span class="hlt">layers</span> such as (LaO)+, (AlO2)‑, etc. The Schottky barriers at these heterointerfaces are found to modulate significantly depending on the charge of the interface <span class="hlt">layer</span>. Large shifts in Schottky barrier <span class="hlt">height</span> due to polar <span class="hlt">layer</span> insertions are explained using a micro-capacitor model. Further, the ionic and electronic contributions to the Schottky barrier <span class="hlt">height</span> at the SrRuO3/SrTiO3 interface are determined and analyzed vis-à-vis basic assumptions of empirical models based on metal-induced gap states (MIGS) and bond polarization theory. In addition, the interface electronic structure and distribution of interface MIGS in SrRuO3/SrTiO3 heterostructures are determined. Furthermore, the electronic structures for SrO- and RuO2-terminated SrRuO3(0 0 1) and SrO- and TiO2-terminated SrTiO3(0 0 1) surfaces are explored and compared to those for SrRuO3/SrTiO3 heterostructures. The modulations in workfunctions of SrO- and RuO2-terminated SrRuO3(0 0 1) surfaces due to polar (LaO)+ and (AlO2)‑ surface monolayers are also examined and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AtmRe.168...49S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AtmRe.168...49S"><span id="translatedtitle">Volcanic <span class="hlt">aerosol</span> <span class="hlt">layer</span> formed in the tropical upper troposphere by the eruption of Mt. Merapi, Java, in November 2010 observed by the spaceborne lidar CALIOP</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shibata, Takashi; Kinoshita, Taro</p> <p>2016-02-01</p> <p>Mt. Merapi in Java, Indonesia, erupted in November 2010. The eruption was proved to be the source of the <span class="hlt">aerosol</span> <span class="hlt">layer</span> observed by a ground-based lidar at Biak, Indonesia, in January 2011 using data on the global distribution of <span class="hlt">aerosols</span> observed by the spaceborne cloud-<span class="hlt">aerosol</span> lidar with orthogonal polarization (CALIOP). These data were used to describe how the volcanic <span class="hlt">aerosols</span> produced by the volcanic eruption diffused throughout the tropical tropopause <span class="hlt">layer</span> (TTL). The equivalent maximum total amount of volcanic SO2 estimated from the spatially integrated total amount of <span class="hlt">aerosols</span> was 0.09 Tg, which is one-third to half that of gaseous SO2 after the eruption was observed by the ozone monitoring instrument satellite. The obtained cirrus-cloud-appearance frequency data exhibit a seasonal cycle having its maximum in winter and no detectable variations that are synchronized with the increase in TTL volcanic <span class="hlt">aerosols</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JGR...10632167B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JGR...10632167B"><span id="translatedtitle">Sudden changes in <span class="hlt">aerosol</span> and gas concentrations in the central Arctic marine boundary <span class="hlt">layer</span>: Causes and consequences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bigg, E. Keith; Leck, Caroline; Nilsson, E. Douglas</p> <p>2001-12-01</p> <p>Measurements of <span class="hlt">aerosol</span> number size distributions and concentrations of the precursor gases dimethyl sulfide, sulfur dioxide and ammonia were made within the pack ice region of the central Arctic Ocean during July and August 1996 from the icebreaker Oden. Changes in concentration, sometimes exceeding the entire seasonal variation, often occurred within an hour and attempts to find the reasons for them are described. Vertical profiles of <span class="hlt">aerosol</span> concentration in Aitken and accumulation mode particles obtained on helicopter flights revealed intense concentration gradients in the lowest 1000 m. Those below 100 m were common. Concentrations of accumulation mode particles were usually greater near the surface than at 100 m. Four representative case studies for which vertical <span class="hlt">aerosol</span> profiles were obtained are presented. Observations of rapid large changes in near-surface concentration of <span class="hlt">aerosols</span> in different size ranges are compared with the vertical profiles, meteorological information, and acoustic or optical remote sensing to infer processes causing the changes. Comparison of simultaneous variations in <span class="hlt">aerosols</span> and precursor gas concentrations are used to define the vertical profiles of the gases. It was found that dimethyl sulfide and ammonia concentrations usually must have been strongly depleted near the surface relative to concentrations at about 100 m. Sulfur dioxide profiles appeared to be more complex. Turbulence or vertical air motions initiated by atmospheric wave motions trapped within the stable boundary <span class="hlt">layer</span> appeared to be directly responsible for many of the sudden concentration changes, through interaction with concentration gradients close to the surface. The presence of low-level jets also had direct or indirect influences on mixing in the lowest few hundred meters. The extent to which <span class="hlt">aerosols</span> measured near the surface can determine the microphysics of central Arctic marine boundary <span class="hlt">layer</span> clouds is examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008ACPD....812461R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008ACPD....812461R"><span id="translatedtitle">Radiative budget in the presence of multi-<span class="hlt">layered</span> <span class="hlt">aerosol</span> structures in the framework of AMMA SOP-0</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raut, J.-C.; Chazette, P.</p> <p>2008-07-01</p> <p>This paper presents radiative transfer calculations performed over Niamey in the UV-Visible range over the period 26th January 1st February during the African Multidisciplinary Monsoon Analysis (AMMA) international program. Climatic effects of <span class="hlt">aerosols</span> along the vertical column have required an accurate determination of their optical properties, which are presented in for a variety of instrumented platforms: Ultralight aircraft, Facility for Airborne Atmospheric Measurements (FAAM) research aircraft, AERONET station. Measurements highlighted the presence of a multi-<span class="hlt">layered</span> structure of mineral dust located below and biomass-burning particles in the more elevated <span class="hlt">layers</span>. Radiative forcing was affected by both the scattering and absorption effects governed by the <span class="hlt">aerosol</span> complex refractive index (ACRI). The best agreement between our results and AERONET optical thicknesses, ground-based extinction measurements and NO2 photolysis rate coefficient was found using the synergy between all the instrumented platforms. The corresponding averaged ACRI were 1.53 (±0.04) 0.047i (±0.006) and 1.52 (±0.04) 0.008i (±0.001) for biomass-burning and mineral dust <span class="hlt">aerosols</span>, respectively. Biomass-burning <span class="hlt">aerosols</span> were characterized by single-scattering albedo ranging from 0.78 to 0.82 and asymmetry parameter ranging from 0.71 to 0.73. For dust <span class="hlt">aerosols</span>, single-scattering albedo (asymmetry parameter) ranged from 0.9 to 0.92 (0.73 to 0.75). The solar energy depletion at the surface is shown to be ~ -21.2 (±1.7) W/m2 as a daily average. At the TOA, the radiative forcing appeared slightly negative but very close to zero (~ -1.4 W/m2). The corresponding atmospheric radiative forcing was found to be ~19.8 (±2.3) W/m2. Mineral dust located below a more absorbing <span class="hlt">layer</span> act as an increase in surface reflectivity of ~3 4%. The radiative forcing is also shown to be highly sensitivity the optical features of the different <span class="hlt">aerosol</span> <span class="hlt">layers</span> (ACRI, optical thickness and <span class="hlt">aerosol</span> vertical</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008ACP.....8.6839R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008ACP.....8.6839R"><span id="translatedtitle">Radiative budget in the presence of multi-<span class="hlt">layered</span> <span class="hlt">aerosol</span> structures in the framework of AMMA SOP-0</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raut, J.-C.; Chazette, P.</p> <p>2008-11-01</p> <p>This paper presents radiative transfer calculations performed over Niamey in the UV-Visible range over the period 26th January 1st February 2006 during the African Multidisciplinary Monsoon Analysis (AMMA) international program. Climatic effects of <span class="hlt">aerosols</span> along the vertical column have required an accurate determination of their optical properties, which are presented here for a variety of instrumented platforms: Ultralight aircraft, Facility for Airborne Atmospheric Measurements (FAAM) research aircraft, AERONET station. Measurements highlighted the presence of a multi-<span class="hlt">layered</span> structure of mineral dust located below and biomass-burning particles in the more elevated <span class="hlt">layers</span>. Radiative forcing was affected by both the scattering and absorption effects governed by the <span class="hlt">aerosol</span> complex refractive index (ACRI). The best agreement between our results and AERONET optical thicknesses, ground-based extinction measurements and NO2 photolysis rate coefficient was found using the synergy between all the instrumented platforms. The corresponding averaged ACRI at 355 nm were 1.53 (±0.04) -0.047i (±0.006) and 1.52 (±0.04) -0.008i (±0.001) for biomass-burning and mineral dust <span class="hlt">aerosols</span>, respectively. Biomass-burning <span class="hlt">aerosols</span> were characterized by single-scattering albedo ranging from 0.78 to 0.82 and asymmetry parameter ranging from 0.71 to 0.73. For dust <span class="hlt">aerosols</span>, single-scattering albedo (asymmetry parameter) ranged from 0.9 to 0.92 (0.73 to 0.75). The solar energy depletion at the surface is shown to be ~-21.2 (±1.7) W/m2 as a daily average. At the TOA, the radiative forcing appeared slightly negative but very close to zero (~-1.4 W/m2). The corresponding atmospheric radiative forcing was found to be ~19.8 (±2.3) W/m2. Mineral dust located below a more absorbing <span class="hlt">layer</span> act as an increase in surface reflectivity of ~3 4%. The radiative forcing is also shown to be highly sensitive to the optical features of the different <span class="hlt">aerosol</span> <span class="hlt">layers</span> (ACRI, optical thickness and <span class="hlt">aerosol</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18758531','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18758531"><span id="translatedtitle">Synergetic technique combining elastic backscatter lidar data and sunphotometer AERONET inversion for retrieval by <span class="hlt">layer</span> of <span class="hlt">aerosol</span> optical and microphysical properties.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cuesta, Juan; Flamant, Pierre H; Flamant, Cyrille</p> <p>2008-09-01</p> <p>We present a so-called lidar and almucantar (LidAlm) algorithm that combines information provided by standard elastic backscatter lidar (i.e., calibrated attenuated backscatter coefficient profile at one or two wavelengths) and sunphotometer AERONET inversion of almucantar like measurements (i.e., column-integrated <span class="hlt">aerosol</span> size distribution and refractive index). The purpose of the LidAlm technique is to characterize the atmospheric column by its different <span class="hlt">aerosol</span> <span class="hlt">layers</span>. These <span class="hlt">layers</span> may be distinct or partially mixed, and they may contain different <span class="hlt">aerosol</span> species (e.g., urban, desert, or biomass burning <span class="hlt">aerosols</span>). The LidAlm synergetic technique provides the extinction and backscatter coefficient profiles, particle size distributions, and backscatter-to-extinction ratios for each <span class="hlt">aerosol</span> <span class="hlt">layer</span>. We present the LidAlm procedure and sensitivity studies. The applications are illustrated with examples of actual atmospheric conditions encountered in the Paris area. PMID:18758531</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920049528&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528Ozone%2Blayer%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920049528&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528Ozone%2Blayer%2529"><span id="translatedtitle">Ozone and <span class="hlt">aerosol</span> distributions measured by airborne lidar during the 1988 Arctic Boundary <span class="hlt">Layer</span> Experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.</p> <p>1991-01-01</p> <p>Consideration is given to O3 and <span class="hlt">aerosol</span> distributions measured from an aircraft using a DIAL system in order to study the sources and sinks of gases and <span class="hlt">aerosols</span> over the tundra regions of Alaska during summer 1988. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low <span class="hlt">aerosol</span> scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HMT....49.1637Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HMT....49.1637Y"><span id="translatedtitle">Transitional boundary <span class="hlt">layer</span> flow and heat transfer over blocked surfaces with influence of free stream velocity and block <span class="hlt">height</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yemenici, O.; Firatoglu, Z. A.</p> <p>2013-11-01</p> <p>Velocity, turbulent intensity, static pressure and temperature measurements over the flat plate and blocked surfaces were investigated in a low speed wind tunnel in the presence of free stream velocity and block <span class="hlt">height</span>. The experiments were carried out for free stream velocities of 5, 7 and 10 m/s encompassing the transitional region and for block <span class="hlt">heights</span> of 10, 15 and 20 mm forming the different flow samples. A constant-temperature anemometer, a micro-manometer and copper-constant thermocouples were used for measurements of velocity and turbulent intensity, static pressure and temperature, respectively. The results showed that the flow separations and reattachments occurred on the blocked surfaces which enhanced the average heat transfer up to 1.54, 1.71 and 1.84 fold of the flat plate value at 5 m/s for the rising block <span class="hlt">height</span>, 1.49, 1.68 and 1.80 at 7 m/s, and 1.44, 1.63 and 1.78 at 10 m/s, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACP....1311317B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACP....1311317B"><span id="translatedtitle">Biogenic VOC oxidation and organic <span class="hlt">aerosol</span> formation in an urban nocturnal boundary <span class="hlt">layer</span>: aircraft vertical profiles in Houston, TX</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, S. S.; Dubé, W. P.; Bahreini, R.; Middlebrook, A. M.; Brock, C. A.; Warneke, C.; de Gouw, J. A.; Washenfelder, R. A.; Atlas, E.; Peischl, J.; Ryerson, T. B.; Holloway, J. S.; Schwarz, J. P.; Spackman, R.; Trainer, M.; Parrish, D. D.; Fehshenfeld, F. C.; Ravishankara, A. R.</p> <p>2013-11-01</p> <p>Organic compounds are a large component of <span class="hlt">aerosol</span> mass, but organic <span class="hlt">aerosol</span> (OA) sources remain poorly characterized. Recent model studies have suggested nighttime oxidation of biogenic hydrocarbons as a potentially large OA source, but analysis of field measurements to test these predictions is sparse. We present nighttime vertical profiles of nitrogen oxides, ozone, VOCs and <span class="hlt">aerosol</span> composition measured during low approaches of the NOAA P-3 aircraft to airfields in Houston, TX. This region has large emissions of both biogenic hydrocarbons and nitrogen oxides. The latter category serves as a source of the nitrate radical, NO3, a key nighttime oxidant. Biogenic VOCs (BVOC) and urban pollutants were concentrated within the nocturnal boundary <span class="hlt">layer</span> (NBL), which varied in depth from 100-400 m. Despite concentrated NOx at low altitude, ozone was never titrated to zero, resulting in rapid NO3 radical production rates of 0.2-2.7 ppbv h-1 within the NBL. Monoterpenes and isoprene were frequently present within the NBL and underwent rapid oxidation (up to 1 ppbv h-1), mainly by NO3 and to a lesser extent O3. Concurrent enhancement in organic and nitrate <span class="hlt">aerosol</span> on several profiles was consistent with primary emissions and with secondary production from nighttime BVOC oxidation, with the latter equivalent to or slightly larger than the former. Some profiles may have been influenced by biomass burning sources as well, making quantitative attribution of organic <span class="hlt">aerosol</span> sources difficult. Ratios of organic <span class="hlt">aerosol</span> to CO within the NBL ranged from 14 to 38 μg m-3 OA/ppmv CO. A box model simulation incorporating monoterpene emissions, oxidant formation rates and monoterpene SOA yields suggested overnight OA production of 0.5 to 9 μg m-3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A23F0392J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A23F0392J&link_type=ABSTRACT"><span id="translatedtitle">Massive-scale aircraft observations of giant sea-salt <span class="hlt">aerosol</span> particle size distributions in atmospheric marine boundary <span class="hlt">layers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jensen, J. B.</p> <p>2015-12-01</p> <p>iant sea-salt <span class="hlt">aerosol</span> particles (dry radius, rd > 0.5 μm) occur nearly everywhere in the marine boundary <span class="hlt">layer</span> and frequently above. This study presents observations of atmospheric sea-salt size distributions in the range 0.7 < rd < 14 μm based on external impaction of sea-spray <span class="hlt">aerosol</span> particles onto microscope polycarbonate microscope slides. The slides have very large sample volumes, typically about 250 L over a 10-second sampling period. This provides unprecedented sampling of giant sea-salt particles for flights in marine boundary <span class="hlt">layer</span> air. The slides were subsequently analyzed in a humidified chamber using dual optical digital microscopy. At a relative humidity of 90% the sea-salt <span class="hlt">aerosol</span> particles form spherical cap drops. Based on measurement the volume of the spherical cap drop and assuming NaCl composition, the Kohler equation is used to derive the dry salt mass of tens of thousands of individual <span class="hlt">aerosol</span> particles on each slide. Size distributions are given with a 0.2 μm resolution. The slides were exposed from the NSF/NCAR C-130 research aircraft during the 2008 VOCALS project off the coast of northern Chile and the 2011 ICE-T in the Caribbean. In each deployment, size distributions using hundreds of slides are used to relate fitted log-normal size distributions parameters to wind speed, altitude and other atmospheric conditions. The size distributions provide a unique observational set for initializing cloud models with coarse-mode <span class="hlt">aerosol</span> particle observations for marine atmospheres.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19750003482&hterms=cloud+bases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcloud%2Bbases','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19750003482&hterms=cloud+bases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcloud%2Bbases"><span id="translatedtitle">Multiple scattering in cloud <span class="hlt">layers</span>; some results. [emphasizing <span class="hlt">aerosol</span> parameters on global basis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vandehulst, H. C.</p> <p>1974-01-01</p> <p>Theoretical methods are discussed for calculating radiative effects of <span class="hlt">aerosols</span>. Experimental determination is emphasized for relevant <span class="hlt">aerosol</span> parameters on a global basis to arrive at realistic estimates of heating and cooling. Internal radiation fields in very thin and very thick slabs are reviewed. Phase functions, polarization, emission by internal sources, and path length distribution are also considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/822178','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/822178"><span id="translatedtitle">Implementation and evaluation of the Heffter method to calculate the <span class="hlt">height</span> of the planetary boundary <span class="hlt">layer</span> above the ARM Southern Great Plains site</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pesenson, Igor</p> <p>2003-11-30</p> <p>This paper explores the Heffter Method--an algorithm for finding the <span class="hlt">height</span> of the Planetary Boundary <span class="hlt">Layer</span> (PBL). The algorithm is applied to the Balloon Borne Sounding System (BBSS) data collected over the Southern Great Plains (SGP) Site of the Atmospheric Radiation Measurement (ARM) Program. After discussing the successes and shortcomings of the algorithm, the resulting PBL <span class="hlt">height</span> estimates for dates in May of 2002 are related to CO{sub 2} concentration and wind data. The CO{sub 2} data used is from the Precision Gas System (PGS) while the wind data is a combination of data from the Portable CO{sub 2} Flux System on the SGP site and BBSS.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007SPIE.6745E..21N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007SPIE.6745E..21N"><span id="translatedtitle">Influence of urban <span class="hlt">aerosol</span> pollution to radiative forcing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nemuc, Anca; Stefan, Sabina; Talianu, Camelia L.</p> <p>2007-10-01</p> <p>Daily PM10 concentrations of samples collected at two sites, urban and rural from Romania have been used to estimate the <span class="hlt">aerosol</span> direct radiative forcing. Using OPAC (Optical Properties of <span class="hlt">Aerosols</span> and Cloud) model we determined the single scattering albedo, the <span class="hlt">aerosol</span> optical depth and <span class="hlt">aerosol</span> up-scatter fraction, <span class="hlt">aerosol</span>'s properties needed to estimate the magnitude and sign of direct <span class="hlt">aerosol</span> radiative forcing. The surface albedo was assumed 0.2 for the urban site and 0.06 for the rural site for all wavelengths. For <span class="hlt">aerosol</span> scale <span class="hlt">height</span> we used 1km in winter and 2 km in the summer to calculate the optical depth of the boundary <span class="hlt">layer</span>. Statistical analysis of the PM10 concentration for both sites show clear seasonal cycle with maxima in the winter. As a consequence of urban atmospheric pollution the radiative forcing for urban site appears strongly modified in comparison with rural site.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRA..117.2302G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRA..117.2302G"><span id="translatedtitle">Empirical model of ionospheric storm effects on the F2 <span class="hlt">layer</span> peak <span class="hlt">height</span> associated with changes of peak electron density</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gulyaeva, T. L.</p> <p>2012-02-01</p> <p>An empirical model of storm-time behavior of the ionospheric peak <span class="hlt">height</span> hmF2 associated with changes of peak electron density NmF2 is inferred from the topside true-<span class="hlt">height</span> profiles provided by ISIS 1, ISIS 2, IK-19, and Cosmos-1809 satellites for the period of 1969-1987. The topside-derived quiet-time models of the ionospheric peak <span class="hlt">height</span> hqF2 and peak electron density NqF2 are used as a frame of reference. To harmonize the model with storm and substorm effects induced by large-scale traveling ionospheric disturbances (LSTIDs), constraints are applied to the topside data, excluding their changes deviating above LSTID extreme limits. The degree of disturbance is estimated by the ionospheric weather W index; then, the least squares fitting is applied to the median of log(hm/hq) versus log(Nm/Nq). Anticorrelation between instant changes of hmF2 and NmF2 has a particular seasonal-magnetic latitude structure varying with solar activity that is used for the buildup of the analytical model. The model allows the deduction of the instantaneous hmF2 associated with the assessment or forecast of the respective NmF2. The model is validated with the data of five ground-based ionosondes during severe space weather storms at times of high solar activity (2000) and low solar activity (2006), and results agree reasonably well with the peak parameters derived from an ionogram. The model is incorporated into the coupled International Reference Ionosphere-Plasmasphere (IRI-Plas) code, used in the assimilative mode as the three-dimensional (3-D) interpolator of the GPS-derived total electron content, TECgps.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26353480','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26353480"><span id="translatedtitle">The Impacts of Contact Etch Stop <span class="hlt">Layer</span> Thickness and Gate <span class="hlt">Height</span> on Channel Stress in Strained N-Metal Oxide Semiconductor Field Effect Transistors.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lin, K C; Twu, M J; Deng, R H; Liu, C H</p> <p>2015-04-01</p> <p>The stress induced by strain in the channel of metal oxide semiconductor field effect transistors (MOSFET) is an effective method to boost the device performance. The geometric dimensions of spacer, gate <span class="hlt">height</span>, and the contact etch stop <span class="hlt">layer</span> (CESL) are important factors among the feasible booster. This study utilized the mismatch of the thermal expansion coefficients of stressors to simulate the process-induced stress in the N-MOSFET. Different temperatures are applied to different region of the device to generate the required strain. The analysis was performed by well-developed finite element package. The composite spacers with variant width of inserted silicon nitride (SiO2/SiN/SiO2, ONO) were proposed and their impacts on channel stress were compared. Two aspects of the impacts of those factors on the channel stress in the longitudinal direction for N-MOSFET with variant channel length were investigated. Firstly, the channel stresses of device without CESL for different gate <span class="hlt">heights</span> were studied. Secondly, with stress applied to CESL and ONO spacers, the induced stresses in the channel were analyzed for long/short gate length. Two conclusions were drawn from the results of simulation. The N-MOSFET device without CESL shows that the stressed spacer alone generates compressive stress and the magnitude increases along with higher gate <span class="hlt">height</span>. The channel stress becomes tensile for device with CESL and increases when the thickness of CESL and the <span class="hlt">height</span> of gate increase, especially for device with shorter gate length. The gate <span class="hlt">height</span> plays more significant role in inducing channel stress compared with the thickness of CESL. The channel stress can be used to quantify the mobility of electron/hole for strained MOSFET device. Therefore, with the guideline disclosed in this study, better device performance can be expected for N-MOSFET. PMID:26353480</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A33I3308B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A33I3308B"><span id="translatedtitle">Using the OMI <span class="hlt">Aerosol</span> Index and Absorption <span class="hlt">Aerosol</span> Optical Depth to Evaluate the NASA MERRA <span class="hlt">Aerosol</span> Reanalysis.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buchard, V.; da Silva, A. M., Jr.; Colarco, P. R.; Darmenov, A.; Govindaraju, R.</p> <p>2014-12-01</p> <p>A radiative transfer interface has been developed to simulate the UV <span class="hlt">Aerosol</span> Index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) <span class="hlt">aerosol</span> assimilated fields. The purpose of this work is to use the AI derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications <span class="hlt">Aerosol</span> Reanalysis (MERRAero). In this presentation we show comparisons of model produced AI with the corresponding OMI measurements during several months of 2007 characterized by a good sampling of dust and biomass burning events. In parallel, model produced Absorption <span class="hlt">Aerosol</span> Optical Depth (AAOD) were compared to OMI AAOD for the same period, identifying regions where the model representation of absorbing <span class="hlt">aerosols</span> were deficient. Since AI is dependent on <span class="hlt">aerosol</span> concentration, optical properties and altitude of the <span class="hlt">aerosol</span> <span class="hlt">layer</span>, we make use of complementary observations to fully diagnose the model, including AOD from the Multi-angle Imaging SpectroRadiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors, <span class="hlt">aerosol</span> retrievals from the <span class="hlt">Aerosol</span> Robotic Network (AERONET) and attenuated backscatter coefficients from the Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission to ascertain misplacement of plume <span class="hlt">height</span> by the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EP%26S...61.1339M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EP%26S...61.1339M"><span id="translatedtitle">The seasonal and solar cycle variations of electron density gradient scale length, vertical drift and <span class="hlt">layer</span> <span class="hlt">height</span> during magnetically quiet days: Implications for Spread F over Trivandrum, India</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manju, G.; Devasia, C. V.; Ravindran, S.</p> <p>2009-12-01</p> <p>A study has been carried out on the behaviour of electron density gradient scale length, L, vertical drift and <span class="hlt">layer</span> <span class="hlt">height</span>, around post sunset hours, during the magnetically quiet days of summer, winter and equinox seasons of solar maximum (2002) and minimum years (1995), using ionosonde data of Trivandrum (8.5°N, 76.5°E, dip = 0.5°N) in the Indian longitude sector. The results indicate a clear seasonal and solar cycle variation in all the three parameters. Further, the seasonal variation of equatorial Spread F (ESF) during the above period is examined in terms of the relative roles of L, the vertical drift and <span class="hlt">layer</span> <span class="hlt">height</span> (of the F <span class="hlt">layer</span>) in the triggering of the collisional Rayleigh-Taylor instability. The results, show for the first time, that L also plays an important role, in controlling the quiet time seasonal and solar cycle variability of ESF; whereas in earlier studies this parameter had been taken to be constant. The detailed results are presented and discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997AtmEn..31.2179T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997AtmEn..31.2179T&link_type=ABSTRACT"><span id="translatedtitle">Chemical relations between atmospheric <span class="hlt">aerosols</span>, deposition and stone decay <span class="hlt">layers</span> on historic buildings at the mediterranean coast</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Torfs, K.; Van Grieken, R.</p> <p></p> <p>To evaluate the effects of the environment on weathering of historical buildings in the Mediterranean Basin, an elaborate study has been carried out at four monuments, with specific interest directed on the action of air pollution and marine salts. The composition of the atmosphere around the monuments has been investigated by monitoring the <span class="hlt">aerosols</span> and the total deposition. These results are combined with the stone decay phenomena to interpret the deterioration at the respective monuments. In Eleusis, Greece, a highly industrialized area, high concentrations of heavy metals and sulphate are found in the <span class="hlt">aerosols</span> and deposition and in the decay <span class="hlt">layers</span> of the stone, while the marine influence is obscured, in spite of its location close to the sea. In Malta and in Cadiz (Spain), the influence of the sea dominates in the stone weathering process. In Bari (Italy), next to the effects of marine <span class="hlt">aerosols</span> on the stone decay inside and outside the building, high concentrations of sulphate are observed on the outside stones. The <span class="hlt">aerosols</span> and depositions reflect a relatively small influence of anthropogenic derived elements; this points out the action of gaseous SO 2 on the stones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27295588','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27295588"><span id="translatedtitle">Study on <span class="hlt">aerosol</span> optical properties and radiative effect in cloudy weather in the Guangzhou region.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Deng, Tao; Deng, XueJiao; Li, Fei; Wang, ShiQiang; Wang, Gang</p> <p>2016-10-15</p> <p>Currently, Guangzhou region was facing the problem of severe air pollution. Large amount of <span class="hlt">aerosols</span> in the polluted air dramatically attenuated solar radiation. This study investigated the vertical optical properties of <span class="hlt">aerosols</span> and inverted the <span class="hlt">height</span> of boundary <span class="hlt">layer</span> in the Guangzhou region using the lidar. Simultaneously, evaluated the impact of different types of clouds on <span class="hlt">aerosol</span> radiation effects using the SBDART. The results showed that the <span class="hlt">height</span> of the boundary <span class="hlt">layer</span> and the surface visibility changed consistently, the average <span class="hlt">height</span> of the boundary <span class="hlt">layer</span> on the hazy days was only 61% of that on clear days. At the <span class="hlt">height</span> of 2km or lower, the <span class="hlt">aerosol</span> extinction coefficient profile distribution decreased linearly along with <span class="hlt">height</span> on clear days, but the haze days saw an exponential decrease. When there was haze, the changing of heating rate of atmosphere caused by the <span class="hlt">aerosol</span> decreased from 3.72K/d to 0.9K/d below the <span class="hlt">height</span> of 2km, and the attenuation of net radiation flux at the ground surface was 97.7W/m(2), and the attenuation amplitude was 11.4%; when there were high clouds, the attenuation was 125.2W/m(2) and the attenuation amplitude was 14.6%; where there were medium cloud, the attenuation was 286.4W/m(2) and the attenuation amplitude was 33.4%. <span class="hlt">Aerosol</span> affected mainly shortwave radiation, and affected long wave radiation very slightly. PMID:27295588</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.9605C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.9605C"><span id="translatedtitle"><span class="hlt">Aerosol</span> chemistry and vertical mixing in the planetary boundary <span class="hlt">layer</span>: insights on the relevant role of nitrate from case studies in Milan (Italy)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Curci, Gabriele</p> <p>2015-04-01</p> <p>Observations of the <span class="hlt">aerosol</span> vertical profile reveal the formation of elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> within and above the planetary boundary <span class="hlt">layer</span> (PBL). Those <span class="hlt">layers</span> may have chemical composition significantly different from that observed near the ground, and the knowledge about the role they play in the budget of the ground-level particulate matter is still incomplete. Here we investigate this aspect combining chemical and physical <span class="hlt">aerosol</span> measurements with WRF/Chem model simulations. The observations were collected in the Milan urban area (Northern Italy) during summer of 2007 and winter of 2008. We find that an important player in shaping the upper <span class="hlt">aerosol</span> <span class="hlt">layers</span> is particulate nitrate, which may reach higher values in the upper PBL (up to 30% of the <span class="hlt">aerosol</span> mass) than the lower. The nitrate formation process is predicted to be largely driven by the relative humidity vertical profile, that may trigger efficient aqueous nitrate formation when exceeding the ammonium nitrate deliquescence point. Secondary PM2.5 produced in the upper half of the PBL may contribute up to 7-8 μg m-3 (or 25%) to ground level concentrations on hourly basis. A large potential role is also found to be played by the residual <span class="hlt">aerosol</span> <span class="hlt">layer</span> above the PBL, which may occasionally contribute up to 10-12 μg m-3(or 40%) to hourly ground level PM2.5 concentrations during the morning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5778571','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5778571"><span id="translatedtitle">Sea-breeze front effects on boundary-<span class="hlt">layer</span> <span class="hlt">aerosols</span> at a tropical coastal station</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Moorthy, K.K.; Murthy, B.V.K.; Nair, P.R. )</p> <p>1993-07-01</p> <p>The effects of sea breeze on optical depth, size distribution, and columnar loading of <span class="hlt">aerosols</span> at the tropical coastal station of Trivandrum are studied. It has been observed that sea-breeze front activity results in a significant and short-lived enhancement in <span class="hlt">aerosol</span> optical depth and columnar loading in contrast to the effects seen on normal sea-breeze days. Examination of the changes in columnar <span class="hlt">aerosol</span> size distribution associated with sea-breeze activity revealed an enhancement of small-particle (size less than 0.28 [mu]m) concentration. The <span class="hlt">aerosol</span> size distribution deduced from optical depth measurements generally show a pronounced bimodal structure associated with the frontal activity. 22 refs., 12 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9680E..2LN&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9680E..2LN&link_type=ABSTRACT"><span id="translatedtitle">Measuring the characteristics of stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span> and total ozone concentration at Siberian Lidar Station in Tomsk</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nevzorov, Aleksey; Bazhenov, Oleg; Burlakov, Vladimir; Dolgii, Sergey</p> <p>2015-11-01</p> <p>We consider the results of long-term remote optical monitoring, obtained at the Siberian Lidar Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences in Tomsk (56.5 °N, 85.0 °E). The scattering characteristics of stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span>, obtained according to data of lidar measurements since 1986, are presented. We analyze the trends of changes in the total ozone (TO) content over Tomsk for the period 1996-2013 according to data of spectrophotometric measurements with employment of TOMS satellite data for the period 1979- 1994. We determined the periods of elevated content of stratospheric <span class="hlt">aerosol</span> over Tomsk after a series of explosive eruptions of volcanoes of Pacific Ring of Fire and Iceland in 2006-2011. Since the second half of 1990s, researchers record an increasing TO trend, equaling 0.65 DU/yr for the period 1996-2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EPJWC.11923007N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EPJWC.11923007N&link_type=ABSTRACT"><span id="translatedtitle">Certain Results of Measurements of Characteristics of Stratospheric <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> and Total Ozone Content at Siberian Lidar Station in Tomsk</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nevzorov, Aleksey; Bazhenov, Oleg; Burlakov, Vladimir; Dolgii, Sergey</p> <p>2016-06-01</p> <p>We consider the results of long-term remote optical monitoring, obtained at the Siberian Lidar Station of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences in Tomsk (56.5°N, 85.0°E). The scattering characteristics of stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span>, obtained according to data of lidar measurements since 1986, are presented. We analyze the trends of changes in the total ozone (TO) content over Tomsk for the period 1996-2013 according to data of spectrophotometric measurements with employment of Total Ozone Mapping Spectrometer (TOMS) data for the period 1979-1994. We determined the periods of elevated content of stratospheric <span class="hlt">aerosol</span> over Tomsk aftera series of explosive eruptions of volcanoes of Pacific Ring of Fire and Iceland in 2006-2011. Since the second half of 1990s, we record an increasing TO trend, equaling 0.65 DU/yr for the period 1996-2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ACPD...1311863B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ACPD...1311863B"><span id="translatedtitle">Biogenic VOC oxidation and organic <span class="hlt">aerosol</span> formation in an urban nocturnal boundary <span class="hlt">layer</span>: aircraft vertical profiles in Houston, TX</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, S. S.; Dubé, W. P.; Bahreini, R.; Middlebrook, A. M.; Brock, C. A.; Warneke, C.; de Gouw, J. A.; Washenfelder, R. A.; Atlas, E.; Peischl, J.; Ryerson, T. B.; Holloway, J. S.; Schwarz, J. P.; Spackman, R.; Trainer, M.; Parrish, D. D.; Fehshenfeld, F. C.; Ravishankara, A. R.</p> <p>2013-05-01</p> <p>Organic compounds are a large component of <span class="hlt">aerosol</span> mass, but organic <span class="hlt">aerosol</span> (OA) sources remain poorly characterized. Recent model studies have suggested nighttime oxidation of biogenic hydrocarbons as a potentially large OA source, but analysis of field measurements to test these predictions is sparse. We present nighttime vertical profiles of nitrogen oxides, ozone, VOCs and <span class="hlt">aerosol</span> composition measured during low approaches of the NOAA P-3 aircraft to airfields in Houston, TX. This region has large emissions of both biogenic hydrocarbons and nitrogen oxides. The latter serves as a source of the nitrate radical, NO3, a key nighttime oxidant. Biogenic VOCs (BVOC) and urban pollutants were concentrated within the nocturnal boundary <span class="hlt">layer</span> (NBL), which varied in depth from 100-400 m. Despite concentrated NOx at low altitude, ozone was never titrated to zero, resulting in rapid NO3 radical production rates of 0.2-2.7ppbv h-1 within the NBL. Monoterpenes and isoprene were frequently present within the NBL and underwent rapid oxidation (up to 1ppbv h-1), mainly by NO3 and to a lesser extent O3. Concurrent enhancement in organic and nitrate <span class="hlt">aerosol</span> on several profiles was consistent with primary emissions and with secondary production from nighttime BVOC oxidation, with the latter equivalent to or slightly larger than the former. Ratios of organic <span class="hlt">aerosol</span> to CO within the NBL ranged from 14 to 38 μg m-3 OA/ppmv CO. A box model simulation incorporating monoterpene emissions, oxidant formation rates and monoterpene SOA yields suggested overnight OA production of 0.5 to 9 μg m-3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011ACPD...1132685W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011ACPD...1132685W&link_type=ABSTRACT"><span id="translatedtitle">Interpretation of FRESCO cloud retrievals in case of absorbing <span class="hlt">aerosol</span> events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, P.; Tuinder, O. N. E.; Tilstra, L. G.; Stammes, P.</p> <p>2011-12-01</p> <p>Cloud and <span class="hlt">aerosol</span> information is needed in trace gas retrievals from satellite measurements. The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO) cloud algorithm employs reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud fraction. In general, clouds contribute more to the O2 A band reflectance than <span class="hlt">aerosols</span>. Therefore, the FRESCO algorithm does not correct for <span class="hlt">aerosol</span> effects in the retrievals and attributes the retrieved cloud information entirely to the presence of clouds, and not to <span class="hlt">aerosols</span>. For events with high <span class="hlt">aerosol</span> loading, <span class="hlt">aerosols</span> may have a dominant effect, especially for almost cloud-free scenes. We have analysed FRESCO cloud data and Absorbing <span class="hlt">Aerosol</span> Index (AAI) data from the Global Ozone Monitoring Experiment (GOME-2) instrument on the Metop-A satellite for events with typical absorbing <span class="hlt">aerosol</span> types, such as volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated with the AAI data for these absorbing <span class="hlt">aerosol</span> events and that the FRESCO cloud pressures contain information on <span class="hlt">aerosol</span> <span class="hlt">layer</span> pressure. For cloud-free scenes, the derived FRESCO cloud pressures are close to those of the <span class="hlt">aerosol</span> <span class="hlt">layer</span> for optically thick <span class="hlt">aerosols</span>. For cloudy scenes, if the strongly absorbing <span class="hlt">aerosols</span> are located above the clouds, then the retrieved FRESCO cloud pressures may represent the <span class="hlt">height</span> of the <span class="hlt">aerosol</span> <span class="hlt">layer</span> rather than the <span class="hlt">height</span> of the clouds. Combining FRESCO cloud data and AAI, an estimate for the <span class="hlt">aerosol</span> <span class="hlt">layer</span> pressure can be given, which can be beneficial for aviation safety and operations in case of e.g. volcanic ash plumes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JGRD..107.4578H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JGRD..107.4578H"><span id="translatedtitle">Retrieving <span class="hlt">aerosol</span> optical depth and type in the boundary <span class="hlt">layer</span> over land and ocean from simultaneous GOME spectrometer and ATSR-2 radiometer measurements, 1, Method description</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holzer-Popp, T.; Schroedter, M.; Gesell, G.</p> <p>2002-11-01</p> <p>A new <span class="hlt">aerosol</span> retrieval method called Synergetic <span class="hlt">Aerosol</span> Retrieval (SYNAER), using simultaneous measurements of the radiometer Along Track Scanning Radiometer (ATSR-2) and the spectrometer Global Ozone Monitoring Experiment (GOME) in the visible and near-infrared spectra, was developed. Both instruments are flown onboard the European Remote Sensing (ERS-2) satellite. SYNAER delivers boundary <span class="hlt">layer</span> <span class="hlt">aerosol</span> optical thickness (BLAOT) and <span class="hlt">aerosol</span> type both over land and over ocean, the latter as BLAOT percentage of six representative components from the Optical Parameters of <span class="hlt">Aerosols</span> and Clouds (OPAC) data set. The high spatial resolution of ATSR-2 permits accurate cloud detection. It allows BLAOT calculation over automatically selected dark pixels and surface albedo correction for a set of boundary <span class="hlt">layer</span> <span class="hlt">aerosol</span> mixtures. After spatial integration and colocation to GOME pixels, these parameters are used to simulate GOME spectra for the same set of <span class="hlt">aerosol</span> mixtures. A least squares fit of these spectra to the measured and cloud-corrected GOME spectrum chooses the <span class="hlt">aerosol</span> mixture. First validation studies are presented in part 2 of this paper [, 2002]. The method will be used for the future sensor pairs Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY)/Advanced ATSR (AATSR) on Envisat and GOME-2/Advanced Very High Resolution Radiometer (AVHRR) on METOP. Thus, SYNAER holds the potential to extract a long-term climatological data set.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1184970-global-regional-modeling-clouds-aerosols-marine-boundary-layer-during-vocals-voca-intercomparison','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1184970-global-regional-modeling-clouds-aerosols-marine-boundary-layer-during-vocals-voca-intercomparison"><span id="translatedtitle">Global and regional modeling of clouds and <span class="hlt">aerosols</span> in the marine boundary <span class="hlt">layer</span> during VOCALS: the VOCA intercomparison</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Wyant, M. C.; Bretherton, Christopher S.; Wood, Robert; Carmichael, Gregory; Clarke, A. D.; Fast, Jerome D.; George, R.; Gustafson, William I.; Hannay, Cecile; Lauer, Axel; et al</p> <p>2015-01-09</p> <p>A diverse collection of models are used to simulate the marine boundary <span class="hlt">layer</span> in the southeast Pacific region during the period of the October–November 2008 VOCALS REx (VAMOS Ocean Cloud Atmosphere Land Study Regional Experiment) field campaign. Regional models simulate the period continuously in boundary-forced free-running mode, while global forecast models and GCMs (general circulation models) are run in forecast mode. The models are compared to extensive observations along a line at 20° S extending westward from the South American coast. Most of the models simulate cloud and <span class="hlt">aerosol</span> characteristics and gradients across the region that are recognizably similar tomore » observations, despite the complex interaction of processes involved in the problem, many of which are parameterized or poorly resolved. Some models simulate the regional low cloud cover well, though many models underestimate MBL (marine boundary <span class="hlt">layer</span>) depth near the coast. Most models qualitatively simulate the observed offshore gradients of SO2, sulfate <span class="hlt">aerosol</span>, CCN (cloud condensation nuclei) concentration in the MBL as well as differences in concentration between the MBL and the free troposphere. Most models also qualitatively capture the decrease in cloud droplet number away from the coast. However, there are large quantitative intermodel differences in both means and gradients of these quantities. Many models are able to represent episodic offshore increases in cloud droplet number and <span class="hlt">aerosol</span> concentrations associated with periods of offshore flow. Most models underestimate CCN (at 0.1% supersaturation) in the MBL and free troposphere. The GCMs also have difficulty simulating coastal gradients in CCN and cloud droplet number concentration near the coast. The overall performance of the models demonstrates their potential utility in simulating aerosol–cloud interactions in the MBL, though quantitative estimation of aerosol–cloud interactions and <span class="hlt">aerosol</span> indirect effects of MBL clouds</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1184970','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1184970"><span id="translatedtitle">Global and regional modeling of clouds and <span class="hlt">aerosols</span> in the marine boundary <span class="hlt">layer</span> during VOCALS: the VOCA intercomparison</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wyant, M. C.; Bretherton, Christopher S.; Wood, Robert; Carmichael, Gregory; Clarke, A. D.; Fast, Jerome D.; George, R.; Gustafson, William I.; Hannay, Cecile; Lauer, Axel; Lin, Yanluan; Morcrette, J. -J.; Mulcahay, Jane; Saide, Pablo; Spak, S. N.; Yang, Qing</p> <p>2015-01-09</p> <p>A diverse collection of models are used to simulate the marine boundary <span class="hlt">layer</span> in the southeast Pacific region during the period of the October–November 2008 VOCALS REx (VAMOS Ocean Cloud Atmosphere Land Study Regional Experiment) field campaign. Regional models simulate the period continuously in boundary-forced free-running mode, while global forecast models and GCMs (general circulation models) are run in forecast mode. The models are compared to extensive observations along a line at 20° S extending westward from the South American coast. Most of the models simulate cloud and <span class="hlt">aerosol</span> characteristics and gradients across the region that are recognizably similar to observations, despite the complex interaction of processes involved in the problem, many of which are parameterized or poorly resolved. Some models simulate the regional low cloud cover well, though many models underestimate MBL (marine boundary <span class="hlt">layer</span>) depth near the coast. Most models qualitatively simulate the observed offshore gradients of SO<sub>2</sub>, sulfate <span class="hlt">aerosol</span>, CCN (cloud condensation nuclei) concentration in the MBL as well as differences in concentration between the MBL and the free troposphere. Most models also qualitatively capture the decrease in cloud droplet number away from the coast. However, there are large quantitative intermodel differences in both means and gradients of these quantities. Many models are able to represent episodic offshore increases in cloud droplet number and <span class="hlt">aerosol</span> concentrations associated with periods of offshore flow. Most models underestimate CCN (at 0.1% supersaturation) in the MBL and free troposphere. The GCMs also have difficulty simulating coastal gradients in CCN and cloud droplet number concentration near the coast. The overall performance of the models demonstrates their potential utility in simulating aerosol–cloud interactions in the MBL, though quantitative estimation of aerosol–cloud interactions and <span class="hlt">aerosol</span> indirect effects of MBL</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AtmEn..41.4638S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AtmEn..41.4638S"><span id="translatedtitle">Optical and chemical properties of marine boundary-<span class="hlt">layer</span> <span class="hlt">aerosol</span> around Japan determined from shipboard measurements in 2002</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shiobara, Masataka; Hara, Keiichiro; Yabuki, Masanori; Kobayashi, Hiroshi</p> <p></p> <p>Shipboard measurements of the optical and chemical properties of marine boundary-<span class="hlt">layer</span> <span class="hlt">aerosol</span> were made around Japan over the period from 28 August to 25 September 2002. Measurements were conducted aboard the Research Vessel (R/V) Shirase along cruise tracks beginning from Yokosuka, and proceeding on to Hakodate, Sakata, Sasebo, Naha, Kure, and Yokkaichi. This paper describes the results of optical measurements using an Optical Particle Counter (OPC), an Integrating Nephelometer (IN), and a Particle Soot/Absorption Photometer (PSAP), as well as chemical analyses of water-soluble <span class="hlt">aerosol</span> particles collected by impactor and filter systems. Coulter Multisizer measurements were used for water-insoluble <span class="hlt">aerosol</span> particles. The complex refractive index (CRI), scattering and absorption coefficients, and size distribution of <span class="hlt">aerosols</span> were estimated from combined measurements made using OPC, IN, and PSAP. Contrasting <span class="hlt">aerosol</span> characteristics were observed during different stages of the cruise. Discussion on these differences focuses mainly on two legs: Leg-1 from Yokosuka to Hakodate and Leg-4 from Sasebo to Naha. Backward trajectory analyses indicate that the air sampled during Leg-1 originated from the Pacific Ocean, whereas the air sampled during Leg-4 originated from the Chinese Continent via the Korean Peninsula. For the first half of Leg-1, the number concentration was low and larger particles were relatively predominant. The real and imaginary parts of the CRI were estimated to be 1.38-1.40 and close to zero, respectively. This estimation is consistent with the results of chemical analyses, which show that the sea salt is rich in <span class="hlt">aerosols</span> sourced from remote ocean areas. In contrast, small particles were predominant during Leg-4, and the real and imaginary parts of the CRI were estimated to be 1.52-1.59 and approximately -0.002, respectively. These findings are also consistent with chemical analyses that reveal a mixture of mineral dust and sulfate <span class="hlt">aerosol</span> likely</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.3094S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.3094S"><span id="translatedtitle">Signature of 3-4 day planetary waves in the equatorial ionospheric F <span class="hlt">layer</span> <span class="hlt">height</span> and medium frequency radar winds over Tirunelveli (8.7oN)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sundararaman, Sathishkumar</p> <p></p> <p>Signature of 3-4 day planetary waves in the equatorial ionospheric F <span class="hlt">layer</span> <span class="hlt">height</span> and medium frequency radar winds over Tirunelveli (8.7oN) S. Sathishkumar1, R. Dhanya1, K. Emperumal1, D. Tiwari2, S. Gurubaran1 and A. Bhattacharyya2 1. Equatorial Geophysical Research Laboratory, Indian Institute of Geomagnetism, Tirunelveli, India 2. Indian Institute of Geomagnetism, Navi Mumbai, India Email: sathishmaths@gmail.com Abstract The equatorial atmosphere-ionosphere system has been studied theoretically and observationally in the past. In the equatorial atmosphere, oscillations with periods of 3-4 days are often observed in the medium frequency (MF) radar over Tirunelveli (8.7oN, 77.8oE, 1.34oN geomag. lat.). Earlier observations show the clear evidence that these waves can propagate from the stratosphere to ionosphere. A digital ionosonde has been providing useful information on several ionospheric parameters from the same site. Simultaneous observations of mesospheric winds using medium frequency radar and F-<span class="hlt">layer</span> <span class="hlt">height</span> (h'F) from ionosonde reveal that the 3-4 day wave was evident in both the component during the 01 June 2007 and 31 July 2007. The 3-4 day wave could have an important role in the day to day variability of the equatorial ionosphere evening uplift. Results from an extensive analysis that is being carried out in the direction of 3-4 day wave present in the ionosphere will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OcScD..12...83Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OcScD..12...83Q"><span id="translatedtitle">Sea surface <span class="hlt">height</span> and mixed <span class="hlt">layer</span> depth responses to sea surface temperature in northwestern Pacific subtropical front zone from spring to summer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qiu, C.; Kawamura, H.; Mao, H.; Wu, J.</p> <p>2015-01-01</p> <p>Qiu et al. (2014) quantitatively examined the mechanisms of sea surface temperature front disappearance, finding that the formation of shallow mixed <span class="hlt">layer</span> depth (MLD) is very important. In the present study, we further investigated variations of the sea level anomaly (SLA) and mixed <span class="hlt">layer</span> depth (MLD) during the SST front weakening period, based on weekly satellite derived products. For the SLA, we examined the steric <span class="hlt">height</span> component of SLA, using empirical orthogonal function (EOF) method and physical method. The seasonal variations of steric <span class="hlt">height</span> from above two methods have the same pattern: peak value (~ 20 cm) occurs in July-August, and minimum value (~ -5 cm) occurs in February to March. Correlation between SLA and SST achieves 0.76 in cold zone and frontal zone, and it is 0.86 between steric component and SST. When SST becomes large, MLD decreases gradually. The linear relationship (y = -4.46 x +156.47) between MLD and SST could be used to estimate the MLD in the subtropical front zone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ACP....16..651J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ACP....16..651J"><span id="translatedtitle">Investigations of boundary <span class="hlt">layer</span> structure, cloud characteristics and vertical mixing of <span class="hlt">aerosols</span> at Barbados with large eddy simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jähn, M.; Muñoz-Esparza, D.; Chouza, F.; Reitebuch, O.; Knoth, O.; Haarig, M.; Ansmann, A.</p> <p>2016-01-01</p> <p>Large eddy simulations (LESs) are performed for the area of the Caribbean island Barbados to investigate island effects on boundary <span class="hlt">layer</span> modification, cloud generation and vertical mixing of <span class="hlt">aerosols</span>. Due to the presence of a topographically structured island surface in the domain center, the model setup has to be designed with open lateral boundaries. In order to generate inflow turbulence consistent with the upstream marine boundary <span class="hlt">layer</span> forcing, we use the cell perturbation method based on finite amplitude potential temperature perturbations. In this work, this method is for the first time tested and validated for moist boundary <span class="hlt">layer</span> simulations with open lateral boundary conditions. Observational data obtained from the SALTRACE field campaign is used for both model initialization and a comparison with Doppler wind and Raman lidar data. Several numerical sensitivity tests are carried out to demonstrate the problems related to "gray zone modeling" when using coarser spatial grid spacings beyond the inertial subrange of three-dimensional turbulence or when the turbulent marine boundary <span class="hlt">layer</span> flow is replaced by laminar winds. Especially cloud properties in the downwind area west of Barbados are markedly affected in these kinds of simulations. Results of an additional simulation with a strong trade-wind inversion reveal its effect on cloud <span class="hlt">layer</span> depth and location. Saharan dust <span class="hlt">layers</span> that reach Barbados via long-range transport over the North Atlantic are included as passive tracers in the model. Effects of <span class="hlt">layer</span> thinning, subsidence and turbulent downward transport near the <span class="hlt">layer</span> bottom at z ≈ 1800 m become apparent. The exact position of these <span class="hlt">layers</span> and strength of downward mixing is found to be mainly controlled atmospheric stability (especially inversion strength) and wind shear. Comparisons of LES model output with wind lidar data show similarities in the downwind vertical wind structure. Additionally, the model results accurately reproduce the</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988GeoRL..15...24P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988GeoRL..15...24P"><span id="translatedtitle">Decay of the El Chichon perturbation to the stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span> - Multispectral ground-based radiometric observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pearson, E. W.; Lebaron, B. A.; Michalsky, J. J.</p> <p>1988-01-01</p> <p>A 9-yr time series of multispectral radiometric observations taken at Rattlesnake Mountain Observatory is analyzed to determine the long-term behavior of the El Chichon-induced perturbation to the stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span>. A technique for determining the volcanic enhancement is described. Time series data for the volcanic enhancement in stratospheric optical depth at wavelengths of 1010, 785, 535, 486, and 428 nm are presented. The main features of the results, slight wavelength dependence and a seasonal oscillation superimposed on the expected exponential decay at all wavelengths, are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010937','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010937"><span id="translatedtitle">Modifications of the Quasi-biennial Oscillation by a Geoengineering Perturbation of the Stratospheric <span class="hlt">Aerosol</span> <span class="hlt">Layer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aquila, V.; Garfinkel, C. I.; Newman, P. A.; Oman, L. D.; Waugh, D. W.</p> <p>2014-01-01</p> <p>This paper examines the impact of geoengineering via stratospheric sulfate <span class="hlt">aerosol</span> on the quasi-biennial oscillation (QBO) using the NASA Goddard Earth Observing System (GEOS-5) Chemistry Climate Model. We performed four 30-year simulations with a continuous injection of sulfur dioxide on the equator at 0 degree longitude. The four simulations differ by the amount of sulfur dioxide injected (5Tg per year and 2.5 Tg per year) and the altitude of the injection (16km-25km and 22km-25km). We find that such an injection dramatically alters the quasi-biennial oscillation, prolonging the phase of easterly shear with respect to the control simulation. In the case of maximum perturbation, i.e. highest stratospheric <span class="hlt">aerosol</span> burden, the lower tropical stratosphere is locked into a permanent westerly QBO phase. This locked QBO westerly phase is caused by the increased <span class="hlt">aerosol</span> heating and associated warming in the tropical lower stratosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020023968&hterms=human+impact+global+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhuman%2Bimpact%252C%2Bglobal%2Bclimate','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020023968&hterms=human+impact+global+climate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhuman%2Bimpact%252C%2Bglobal%2Bclimate"><span id="translatedtitle">Global Lidar Observations of <span class="hlt">Aerosol</span> Distribution and Radiative Influence</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spinhirne, James; Starr, David OC. (Technical Monitor)</p> <p>2001-01-01</p> <p>A very visible impact of human activities is the brownish <span class="hlt">aerosol</span> haze that pervades many industrialized regions as well as areas in the subtropics and tropics where biomass burning occurs. Well known examples are the Asian Brown Cloud, Arctic Haze and East Coast Haze. Atmospheric transport transforms this haze into regional and hemispheric <span class="hlt">aerosol</span> <span class="hlt">layers</span> of significant concentrations. The overall impact on the radiation balance of the atmosphere, surface solar irradiance and other meteorology factors is recognized as a major uncertainty for climate change. In order to understand the impact, the global distribution of <span class="hlt">aerosol</span> and their properties must be known. . A missing element of observations, but critical for understanding transport has been the <span class="hlt">height</span> distribution of <span class="hlt">aerosol</span>. Lidar measurements of <span class="hlt">aerosol</span> <span class="hlt">height</span> distribution have been important in GLOBE, ACE, INDOEX and other field studies A network of continuously operating eye safe lidar ground sites has now been established for baseline <span class="hlt">aerosol</span> profiling. In 2002 NASA will launch the Geoscience Laser Altimeter System (GLAS) mission which will provide for the first time global observations of the <span class="hlt">height</span> distribution of <span class="hlt">aerosol</span>. The combination of these and other modem satellite observations, field experiments and models of global <span class="hlt">aerosol</span> composition and transport should begin to unravel the impacts of particles in the atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACP....15.7173V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACP....15.7173V"><span id="translatedtitle">Fire emission <span class="hlt">heights</span> in the climate system - Part 2: Impact on transport, black carbon concentrations and radiation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Veira, A.; Kloster, S.; Schutgens, N. A. J.; Kaiser, J. W.</p> <p>2015-07-01</p> <p> into the free troposphere (FT) and 75 % into the planetary boundary <span class="hlt">layer</span> (PBL), leads to a TOA RF of -0.24±0.06 W m-2. Overall, we conclude that simple plume <span class="hlt">height</span> parametrizations provide sufficient representations of emission <span class="hlt">heights</span> for global climate modeling. Significant improvements in <span class="hlt">aerosol</span> wildfire modeling likely depend on better emission inventories and <span class="hlt">aerosol</span> process modeling rather than on improved emission <span class="hlt">height</span> parametrizations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999GeoRL..26..595T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999GeoRL..26..595T"><span id="translatedtitle">Aircraft measurements of ozone, NOx, CO, and <span class="hlt">aerosol</span> concentrations in biomass burning smoke over Indonesia and Australia in October 1997: Depleted ozone <span class="hlt">layer</span> at low altitude over Indonesia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsutsumi, Yukitomo; Sawa, Yousuke; Makino, Yukio; Jensen, Jørgen B.; Gras, John L.; Ryan, Brian F.; Diharto, Sri; Harjanto, Hery</p> <p></p> <p>The 1997 El Niño unfolded as one of the most sever El Niño Southern Oscillation (ENSO) events in this century and it coincided with massive biomass burning in the equatorial western Pacific region. To assess the influence on the atmosphere, aircraft observations of trace gases and <span class="hlt">aerosol</span> were conducted over Kalimantan in Indonesia and Australia. Over Kalimantan in Indonesia, high concentrations of O3, NOx, CO, and <span class="hlt">aerosols</span> were observed during the flight. Although the <span class="hlt">aerosol</span> and NOx decreased with altitude, the O3 had the maximum concentration (80.5 ppbv) in the middle <span class="hlt">layer</span> of the smoke haze and recorded very low concentrations (˜20 ppbv) in the lower smoke <span class="hlt">layer</span>. This feature was not observed in the Australian smoke. We proposed several hypotheses for the low O3 concentration at low levels over Kalimantan. The most likely are lack of solar radiation and losses at the surface of <span class="hlt">aerosol</span> particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJWC.11924003M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJWC.11924003M"><span id="translatedtitle">Complex <span class="hlt">Aerosol</span> Experiment in Western Siberia (April - October 2013)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matvienko, G. G.; Belan, B. D.; Panchenko, M. V.; Romanovskii, O. A.; Sakerin, S. M.; Kabanov, D. M.; Turchinovich, S. A.; Turchinovich, Yu. S.; Eremina, T. A.; Kozlov, V. S.; Terpugova, S. A.; Pol'kin, V. V.; Yausheva, E. P.; Chernov, D. G.; Zuravleva, T. B.; Bedareva, T. V.; Odintsov, S. L.; Burlakov, V. D.; Arshinov, M. Yu.; Ivlev, G. A.; Savkin, D. E.; Fofonov, A. V.; Gladkikh, V. A.; Kamardin, A. P.; Balin, Yu. S.; Kokhanenko, G. P.; Penner, I. E.; Samoilova, S. V.; Antokhin, P. N.; Arshinova, V. G.; Davydov, D. K.; Kozlov, A. V.; Pestunov, D. A.; Rasskazchikova, T. M.; Simonenkov, D. V.; Sklyadneva, T. K.; Tolmachev, G. N.; Belan, S. B.; Shmargunov, V. P.</p> <p>2016-06-01</p> <p>The primary project objective was to accomplish the Complex <span class="hlt">Aerosol</span> Experiment, during which the <span class="hlt">aerosol</span> properties should be measured in the near-ground <span class="hlt">layer</span> and free atmosphere. Three measurement cycles were performed during the project implementation: in spring period (April), when the maximum of <span class="hlt">aerosol</span> generation is observed; in summer (July), when atmospheric boundary <span class="hlt">layer</span> <span class="hlt">height</span> and mixing <span class="hlt">layer</span> <span class="hlt">height</span> are maximal; and in late summer - early autumn (October), when the secondary particle nucleation period is recorded. Numerical calculations were compared with measurements of fluxes of downward solar radiation. It was shown that the relative differences between model and experimental values of fluxes of direct and total radiation, on the average, do not exceed 1% and 3% respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JaJAP..55dEB12S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JaJAP..55dEB12S"><span id="translatedtitle">Growth of ultrahigh-Sn-content Ge1- x Sn x epitaxial <span class="hlt">layer</span> and its impact on controlling Schottky barrier <span class="hlt">height</span> of metal/Ge contact</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suzuki, Akihiro; Nakatsuka, Osamu; Shibayama, Shigehisa; Sakashita, Mitsuo; Takeuchi, Wakana; Kurosawa, Masashi; Zaima, Shigeaki</p> <p>2016-04-01</p> <p>We examined the epitaxial growth of an ultrahigh-Sn-content Ge1- x Sn x <span class="hlt">layer</span> on a Ge substrate and investigated the impact of a Ge1- x Sn x interlayer on the Schottky barrier <span class="hlt">height</span> (SBH) of the metal/Ge contact. In this study, we considered guidelines of the strain energy and growth temperature to realize a high-Sn-content Ge1- x Sn x <span class="hlt">layer</span> while keeping the epitaxial growth and suppressing the Sn precipitation. By reducing the film thickness and keeping a low growth temperature, we formed an atomically flat and uniform Ge1- x Sn x epitaxial <span class="hlt">layer</span> with a Sn content up to 46% on a Ge(001) substrate. We also performed the current density-voltage measurement for Al/Ge1- x Sn x /n-Ge Schottky diodes to estimate the SBH. We found that the SBH of Al/Ge1- x Sn x /n-Ge contact decreases with increasing Sn content in the Ge1- x Sn x interlayer. The shift of the pinning position towards the conduction band edge of Ge is one of the reasons for the SBH reduction of Al/Ge1- x Sn x /n-Ge contact because the valence band edge of Ge1- x Sn x would rise as the Sn content increases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A51I0194A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A51I0194A"><span id="translatedtitle">Spatial and Temporal Variation of Boundary <span class="hlt">Layer</span> Lapse Rate and Cloud-top-<span class="hlt">height</span> Observed from MODIS, CALIPSO and AMSR-E over Eastern Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adhikari, L.; Xie, F.; Winning, T.</p> <p>2015-12-01</p> <p>The strong free tropospheric subsidence and the cool sea surface temperatures over the subtropical eastern Pacific Ocean often lead to a shallow and cloudy planetary boundary <span class="hlt">layer</span> (PBL) capped by a strong inversion. These low PBL clouds are crucial for understanding the ocean-atmosphere interaction and the cloud-radiation feedback processes. However, accurate identification/representation of these clouds remains a key challenge in both satellite observations and global climate model simulations. Specifically, the cloud transition from the near-shore stratocumulus to trade-cumulus remains a huge challenge in climate models and warrants high-quality PBL observations from space. The MODIS collection 6 cloud top <span class="hlt">height</span> vastly improves the global PBL cloud top <span class="hlt">heights</span> (CTH) compared to collection 5. However, the MODIS collection 6 CTH still shows systematic higher CTH than CALIPSO in the subtropical subsidence region, which is likely due to the underestimation of lapse rate. This study presents the seasonal climatology of PBL lapse rate derived from multi-year CALIPSO with co-incident MODIS CTT and AMSR-E SST measurements. The lapse rate climatology is validated by the high-resolution radiosonde observations and then used to derive the CTH from MODIS measurements. Comparison of the new lapse rate based MODIS CTH with CALIPSO CTH will be presented. The PBL <span class="hlt">height</span> derived from the COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) GPS radio occultation (RO) will be used to evaluate the MODIS CTH as an independent dataset. The discrepancies over the transition from stratus to trade-cumuli regions (broken clouds) will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJWC.11924007S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJWC.11924007S"><span id="translatedtitle">Local - Air Project: Tropospheric <span class="hlt">Aerosol</span> Monitoring by CALIPSO Lidar Satellite and Ground-Based Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sarli, V.; Trippetta, S.; Bitonto, P.; Papagiannopoulos, N.; Caggiano, R.; Donvito, A.; Mona, L.</p> <p>2016-06-01</p> <p>A new method for the detection of the Planetary Boundary <span class="hlt">Layer</span> (PBL) <span class="hlt">height</span> from CALIPSO space-borne lidar data was developed and the possibility to infer the sub-micrometric <span class="hlt">aerosol</span> particle (i.e., PM1) concentrations at ground level from CALIPSO observations was also explored. The comparison with ground-based lidar measurements from an EARLINET (European <span class="hlt">Aerosol</span> Research LIdar Network) station showed the reliability of the developed method for the PBL. Moreover, empirical relationships between integrated backscatter values from CALIPSO and PM1 concentrations were found thanks to the combined use of the retrieved PBL <span class="hlt">heights</span>, CALIPSO <span class="hlt">aerosol</span> profiles and typing and PM1 insitu measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACPD...1535237G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACPD...1535237G"><span id="translatedtitle">Optical and microphysical characterization of <span class="hlt">aerosol</span> <span class="hlt">layers</span> over South Africa by means of multi-wavelength depolarization and Raman lidar measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Giannakaki, E.; van Zyl, P. G.; Müller, D.; Balis, D.; Komppula, M.</p> <p>2015-12-01</p> <p>Optical and microphysical properties of different <span class="hlt">aerosol</span> types over South Africa measured with a multi-wavelength polarization Raman lidar are presented. This study could assist in bridging existing gaps relating to <span class="hlt">aerosol</span> properties over South Africa, since limited long-term data of this type is available for this region. The observations were performed under the framework of the EUCAARI campaign in Elandsfontein. The multi-wavelength PollyXT Raman lidar system was used to determine vertical profiles of the <span class="hlt">aerosol</span> optical properties, i.e. extinction and backscatter coefficients, Ångström exponents, lidar ratio and depolarization ratio. The mean microphysical <span class="hlt">aerosol</span> proper ties, i.e. effective radius and single scattering, albedo were retrieved with an advanced inversion algorithm. Clear differences were observed for the intensive optical properties of atmospheric <span class="hlt">layers</span> of biomass burning and urban/industrial <span class="hlt">aerosols</span>. Our results reveal a wide range of optical and microphysical parameters for biomass burning <span class="hlt">aerosols</span>. This indicates probable mixing of biomass burning <span class="hlt">aerosols</span> with desert dust particles, as well as the possible continuous influence of urban/industrial <span class="hlt">aerosol</span> load in the region. The lidar ratio at 355 nm, the linear particle depolarization ratio at 355 nm and the extinction-related Ångström exponent from 355 to 532 nm were 52 ± 7 sr; 0.9 ± 0.4 % and 2.3 ± 0.5, respectively for urban/industrial <span class="hlt">aerosols</span>, while these values were 92 ± 10 sr; 3.2 ± 1.3 %; 2.0 ± 0.4 respectively for biomass burning <span class="hlt">aerosols</span> <span class="hlt">layers</span>. Biomass burning particles are larger and slightly less absorbing compared to urban/industrial <span class="hlt">aerosols</span>. The particle effective radius were found to be 0.10 ± 0.03, 0.17 ± 0.04 and 0.13 ± 0.03 μm for urban/industrial, biomass burning, and mixed biomass burning and desert dust <span class="hlt">aerosols</span>, respectively, while the single scattering albedo at 532 nm were 0.87 ± 0.06, 0.90 ± 0.06, and 0.88 ± 0.07 (at 532 nm), respectively for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.8109G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.8109G&link_type=ABSTRACT"><span id="translatedtitle">Optical and microphysical characterization of <span class="hlt">aerosol</span> <span class="hlt">layers</span> over South Africa by means of multi-wavelength depolarization and Raman lidar measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Giannakaki, Elina; van Zyl, Pieter G.; Müller, Detlef; Balis, Dimitris; Komppula, Mika</p> <p>2016-07-01</p> <p>Optical and microphysical properties of different <span class="hlt">aerosol</span> types over South Africa measured with a multi-wavelength polarization Raman lidar are presented. This study could assist in bridging existing gaps relating to <span class="hlt">aerosol</span> properties over South Africa, since limited long-term data of this type are available for this region. The observations were performed under the framework of the EUCAARI campaign in Elandsfontein. The multi-wavelength PollyXT Raman lidar system was used to determine vertical profiles of the <span class="hlt">aerosol</span> optical properties, i.e. extinction and backscatter coefficients, Ångström exponents, lidar ratio and depolarization ratio. The mean microphysical <span class="hlt">aerosol</span> properties, i.e. effective radius and single-scattering albedo, were retrieved with an advanced inversion algorithm. Clear differences were observed for the intensive optical properties of atmospheric <span class="hlt">layers</span> of biomass burning and urban/industrial <span class="hlt">aerosols</span>. Our results reveal a wide range of optical and microphysical parameters for biomass burning <span class="hlt">aerosols</span>. This indicates probable mixing of biomass burning <span class="hlt">aerosols</span> with desert dust particles, as well as the possible continuous influence of urban/industrial <span class="hlt">aerosol</span> load in the region. The lidar ratio at 355 nm, the lidar ratio at 532 nm, the linear particle depolarization ratio at 355 nm and the extinction-related Ångström exponent from 355 to 532 nm were 52 ± 7 sr, 41 ± 13 sr, 0.9 ± 0.4 % and 2.3 ± 0.5, respectively, for urban/industrial <span class="hlt">aerosols</span>, while these values were 92 ± 10 sr, 75 ± 14 sr, 3.2 ± 1.3 % and 1.7 ± 0.3, respectively, for biomass burning <span class="hlt">aerosol</span> <span class="hlt">layers</span>. Biomass burning particles are larger and slightly less absorbing compared to urban/industrial <span class="hlt">aerosols</span>. The particle effective radius were found to be 0.10 ± 0.03, 0.17 ± 0.04 and 0.13 ± 0.03 µm for urban/industrial, biomass burning, and mixed <span class="hlt">aerosols</span>, respectively, while the single-scattering albedo at 532 nm was 0.87 ± 0.06, 0.90 ± 0.06, and 0.88 ± 0.07 (at 532</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1111120P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1111120P"><span id="translatedtitle">ACCURATE: Influence of Cloud <span class="hlt">Layers</span> and <span class="hlt">Aerosol</span> on Infrared Laser Occultation Signals for Sensing of Greenhouse Gases</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Proschek, V.; Schweitzer, S.; Emde, C.; Ladstädter, F.; Fritzer, J.; Kirchengast, G.</p> <p>2009-04-01</p> <p>ACCURATE (Atmospheric Climate and Chemistry in the UTLS Region And climate Trends Explorer), a new climate satellite concept, enables simultaneous measurement of profiles of greenhouse gases, isotopes, wind and thermodynamic variables from Low Earth Orbit (LEO) satellites. The measurement principle applied is a combination of the novel LEO-LEO infrared laser occultation (LIO) technique and the well-studied but not yet flown LEO-LEO microwave occultation (LMO) technique. As intrinsic to the space-borne occultation technique, the measurements are evenly distributed around the world, have high vertical resolution and high accuracy and are stable over long time periods. The LIO uses near-monochromatic signals in the short-wave infrared range (~2-2.5 m in the case of ACCURATE) which are absorbed by various trace species in the Earth's atmosphere. From signal transmission measurements, profiles of the concentration of the absorbing species can be derived given that temperature and pressure are accurately known from LMO. The current ACCURATE mission design is arranged for the measurement of six greenhouse gases (H2O, CO2, CH4, N2O, O3, CO) and four isotopes (13CO2, C18OO, HDO, H218O) with focus on the upper troposphere/lower stratosphere region (UTLS, 5-35 km). Wind speed in line-of-sight can be derived from a line-symmetric transmission difference which is caused by wind-induced Doppler shift. By-products are information on cloud <span class="hlt">layering</span>, <span class="hlt">aerosol</span> extinction and scintillation strength. This contribution presents an overview on the ACCURATE mission design and the expected accuracy of retrieved atmospheric variables and further focuses on the influence of clouds and <span class="hlt">aerosols</span> on propagating LIO signals. Special emphasis will be given to sub-visible cirrus clouds which are semi-transparent to infrared signals. A simple frequency dependent cloud extinction parametrization was included into the occultation propagation software EGOPS and evaluated against results of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ACP....10.1155R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ACP....10.1155R"><span id="translatedtitle">Absorption Angstrom Exponent in AERONET and related data as an indicator of <span class="hlt">aerosol</span> composition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Russell, P. B.; Bergstrom, R. W.; Shinozuka, Y.; Clarke, A. D.; Decarlo, P. F.; Jimenez, J. L.; Livingston, J. M.; Redemann, J.; Dubovik, O.; Strawa, A.</p> <p>2010-02-01</p> <p> ultraviolet and CALIPSO <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">heights</span> to reduce <span class="hlt">height</span>-absorption ambiguity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JGRD..11911355L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JGRD..11911355L&link_type=ABSTRACT"><span id="translatedtitle">Accuracy of near-surface <span class="hlt">aerosol</span> extinction determined from columnar <span class="hlt">aerosol</span> optical depth measurements in Reno, NV, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Loría-Salazar, S. Marcela; Arnott, W. Patrick; Moosmüller, Hans</p> <p>2014-10-01</p> <p>The aim of the present work is a detailed analysis of <span class="hlt">aerosol</span> columnar optical depth as a tool to determine near-surface <span class="hlt">aerosol</span> extinction in Reno, Nevada, USA, during the summer of 2012. Ground and columnar <span class="hlt">aerosol</span> optical properties were obtained by use of in situ Photoacoustic and Integrated Nephelometer and Cimel CE-318 Sun photometer instruments, respectively. Both techniques showed that seasonal weather changes and fire plumes had enormous influence on local <span class="hlt">aerosol</span> optics. The apparent optical <span class="hlt">height</span> followed the shape but not magnitude of the development of the convective boundary <span class="hlt">layer</span> when fire conditions were not present. Back trajectory analysis demonstrated that a local flow known as the Washoe Zephyr circulation often induced <span class="hlt">aerosol</span> transport from Northern California over the Sierra Nevada Mountains that increased the <span class="hlt">aerosol</span> optical depth at 500 nm during afternoons when compared with mornings. <span class="hlt">Aerosol</span> fine mode fraction indicated that afternoon <span class="hlt">aerosols</span> in June and July and fire plumes in August were dominated by submicron particles, suggesting upwind urban plume biogenically enhanced evolution toward substantial secondary <span class="hlt">aerosol</span> formation. This fine particle optical depth was inferred to be beyond the surface, thereby complicating use of remote sensing measurements for near-ground <span class="hlt">aerosol</span> extinction measurements. It is likely that coarse mode depletes fine mode <span class="hlt">aerosol</span> near the surface by coagulation and condensation of precursor gases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.A14C..01E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.A14C..01E"><span id="translatedtitle">Trace Gases and <span class="hlt">Aerosol</span> in the Boundary <span class="hlt">Layer</span> of the Northern Asia: TROICA Experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elanksy, N. F.; Aloyan, A. E.; Berezina, E. V.; Elokhov, A. S.; Brenninkmeijer, C. A.; Kopeikin, V. M.; Moeseenko, K. B.; Lavrova, O. V.; Pankratova, N. V.; Safronov, A. N.; Shumsky, R. A.; Skorokhod, A. I.; Tarasova, O. A.; Vivchar, A. V.; Grisenko, A. M.</p> <p>2007-12-01</p> <p>The TROICA experiment (Transcontinental Observations Into the Chemistry of the Atmosphere) started in 1995. A mobile railroad laboratory is being used for measurements of atmospheric gases, <span class="hlt">aerosol</span>, solar radiation and meteorological parameters. The laboratory wagon is directly coupled to the locomotive of a passenger train traveling along electrified railroads of Russia. Eleven expeditions have been conducted to the moment of which nine were performed along the Trans-Siberian railroad from Moscow to Vladivostok (around 9300 km). One expedition was North-South between Murmansk and Kislovodsk, and one was around the mega-city of Moscow. The huge coverage of the continental regions and the repetition of the expeditions provide unique information on processes controlling variability of the key trace gases (O3, NOx, CO, CO2, CH4, some VOCs) and <span class="hlt">aerosols</span> with high temporal and spatial resolution over different scales from continental to local (hundreds meters). Multiple crossings of settlements allowed determining typical variations of surface gases and <span class="hlt">aerosol</span> concentrations within cities and their plumes. 222Rn concentration data were used for estimates of CO, CH4 and CO2 nocturnal fluxes from the soil and vegetation. Impacts of different factors, like Western Siberian gas and oil industry, forest fires, transboundary air pollution transport and some other can be evaluated based on the measurement data by comparing them with results of model output and hence can be used for model validation. Emissions of the atmospheric CO and CH4 were studied in several expeditions using isotopes analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110013675&hterms=Vargas&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D30%26Ntt%3DVargas','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110013675&hterms=Vargas&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D30%26Ntt%3DVargas"><span id="translatedtitle">Major Influence of Tropical Volcanic Eruptions on the Stratospheric <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> During the Last Decade</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vernier, Jean-Paul; Thomason, Larry W.; Pommereau, J.-P.; Bourassa, Adam; Pelon, Jacques; Garnier, Anne; Hauchecorne, A.; Blanot, L.; Trepte, Charles R.; Degenstein, Doug; Vargas, F.</p> <p>2011-01-01</p> <p>The variability of stratospheric <span class="hlt">aerosol</span> loading between 1985 and 2010 is explored with measurements from SAGE II, CALIPSO, GOMOS/ENVISAT, and OSIRIS/Odin space-based instruments. We find that, following the 1991 eruption of Mount Pinatubo, stratospheric <span class="hlt">aerosol</span> levels increased by as much as two orders of magnitude and only reached background levels between 1998 and 2002. From 2002 onwards, a systematic increase has been reported by a number of investigators. Recently, the trend, based on ground-based lidar measurements, has been tentatively attributed to an increase of SO2 entering the stratosphere associated with coal burning in Southeast Asia. However, we demonstrate with these satellite measurements that the observed trend is mainly driven by a series of moderate but increasingly intense volcanic eruptions primarily at tropical latitudes. These events injected sulfur directly to altitudes between 18 and 20 km. The resulting <span class="hlt">aerosol</span> particles are slowly lofted into the middle stratosphere by the Brewer-Dobson circulation and are eventually transported to higher latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.5705B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.5705B&link_type=ABSTRACT"><span id="translatedtitle">Validation of ash optical depth and <span class="hlt">layer</span> <span class="hlt">height</span> retrieved from passive satellite sensors using EARLINET and airborne lidar data: the case of the Eyjafjallajökull eruption</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balis, Dimitris; Koukouli, Maria-Elissavet; Siomos, Nikolaos; Dimopoulos, Spyridon; Mona, Lucia; Pappalardo, Gelsomina; Marenco, Franco; Clarisse, Lieven; Ventress, Lucy J.; Carboni, Elisa; Grainger, Roy G.; Wang, Ping; Tilstra, Gijsbert; van der A, Ronald; Theys, Nicolas; Zehner, Claus</p> <p>2016-05-01</p> <p>The vulnerability of the European airspace to volcanic eruptions was brought to the attention of the public and the scientific community by the 2010 eruptions of the Icelandic volcano Eyjafjallajökull. As a consequence of this event, ash concentration thresholds replaced the "zero tolerance to ash" rule, drastically changing the requirements on satellite ash retrievals. In response to that, the ESA funded several projects aiming at creating an optimal end-to-end system for volcanic ash plume monitoring and prediction. Two of them, namely the SACS-2 and SMASH projects, developed and improved dedicated satellite-derived ash plume and sulfur dioxide level assessments. The validation of volcanic ash levels and <span class="hlt">height</span> extracted from the GOME-2 and IASI instruments on board the MetOp-A satellite is presented in this work. EARLINET lidar measurements are compared to different satellite retrievals for two eruptive episodes in April and May 2010. Comparisons were also made between satellite retrievals and aircraft lidar data obtained with the UK's BAe-146-301 Atmospheric Research Aircraft (managed by the Facility for Airborne Atmospheric Measurements, FAAM) over the United Kingdom and the surrounding regions. The validation results are promising for most satellite products and are within the estimated uncertainties of each of the comparative data sets, but more collocation scenes would be desirable to perform a comprehensive statistical analysis. The satellite estimates and the validation data sets are better correlated for high ash optical depth values, with correlation coefficients greater than 0.8. The IASI retrievals show a better agreement concerning the ash optical depth and ash <span class="hlt">layer</span> <span class="hlt">height</span> when compared with the ground-based and airborne lidar data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8795E..17M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8795E..17M"><span id="translatedtitle">Complex vertical <span class="hlt">layering</span> and mixing of <span class="hlt">aerosols</span> over the eastern Mediterranean: active and passive remote sensing at the Cyprus University of Technology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mamouri, R.-E.; Nisantzi, A.; Hadjimitsis, D. G.; Ansmann, A.; Schwarz, A.; Basart, S.; Baldasano, J. M.</p> <p>2013-08-01</p> <p><span class="hlt">Aerosols</span> can have a complicated influence on climate conditions, directly as well as indirectly via cloud formation. The southeastern Mediterranean region can be characterized as a cross road of <span class="hlt">aerosols</span> originating from European, Asian and African continents. Complex vertical <span class="hlt">aerosol</span> distributions are frequently detected over Cyprus by means of active remote sensing. Observations of such complex <span class="hlt">aerosol</span> <span class="hlt">layering</span> and comparison of the measurements with <span class="hlt">aerosol</span> products of regional and global atmospheric transport models are required to improve our understanding of life cycles of <span class="hlt">aerosol</span> mixtures and their impact on climate as well as on satellite remote sensing products. In this study, a case of an intense desert dust outbreak from Syria and Saudi Arabia towards the eastern Mediterranean in September 2011 is presented. The observations used in this study were performed with a 532-nm polarization Lidar and a sun/sky AERONET photometer operated at 8 channels from 340 to 1640 nm wavelength. Both instruments belong to remote sensing station of the Cyprus Technical University at Limassol, Cyprus (34°N, 33°E). The lofted dust plume was doped with air masses that crossed sources of biomass burning smoke and anthropogenic pollution. In addition, the shallow marine boundary <span class="hlt">layer</span> over the Mediterranean Sea and over Limassol became mixed with the anthropogenic haze by sea breeze circulations. The case study demonstrates the potential of combined lidar/photometer observations to deliver detailed vertically resolved information of the <span class="hlt">aerosol</span> characteristics in terms of particle optical and microphysical properties, separately for the spherical particle fraction as well as for the non-spherical <span class="hlt">aerosol</span> mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.2981M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.2981M"><span id="translatedtitle">Observational evidence for <span class="hlt">aerosol</span> invigoration in shallow cumulus downstream of Mount Kilauea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mace, G. G.; Abernathy, A. C.</p> <p>2016-03-01</p> <p>Knowledge of how marine boundary <span class="hlt">layer</span> (MBL) shallow cumulus clouds respond to changes in <span class="hlt">aerosol</span> is central to understanding how MBL clouds modulate the climate system. Mount Kilauea on the island of Hawaii began erupting in 2008 injecting substantial SO2 into the marine boundary <span class="hlt">layer</span> creating a unique natural laboratory. Examining data from approximately 600 passes of the A-Train downstream of Mount Kilauea over a 3 year period and separating data into <span class="hlt">aerosol</span> optical depth quartiles, we find an unambiguous increase in marine boundary cloud top <span class="hlt">height</span> and an increase in surface wind speed as <span class="hlt">aerosol</span> increases while the radar reflectivity does not change substantially. We conclude that increased <span class="hlt">aerosols</span> may have caused invigoration of the MBL clouds. Additionally, we find that increases in sub 1 km cloud fraction combined with increasing <span class="hlt">aerosol</span> explain the increased visible reflectance suggesting that evidence for the so-called first <span class="hlt">aerosol</span> indirect effect should be reexamined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=great+AND+height&pg=3&id=ED001006','ERIC'); return false;" href="http://eric.ed.gov/?q=great+AND+height&pg=3&id=ED001006"><span id="translatedtitle"><span class="hlt">HEIGHTS</span> PROGRAM.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>POTTER, LOUIS A.</p> <p></p> <p>THE "<span class="hlt">HEIGHTS</span>" PROGRAM, AS PART OF THE GREAT CITIES SCHOOL IMPROVEMENT PROGRAM, IS BASED ON THE BELIEF THAT MUCH CAN BE DONE TO CHANGE THE PATTERNS OF ASPIRATION, ACHIEVEMENT, AND ADJUSTMENT WHICH CULTURALLY DEPRIVED YOUTH TEND TO FOLLOW. TRADITIONAL GOALS OF EDUCATION WILL BE FOLLOWED, BUT THE TEACHERS AND STAFF WILL HAVE AT THEIR DISPOSAL A GROUP…</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACP....15.5743B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACP....15.5743B"><span id="translatedtitle">Using the OMI <span class="hlt">aerosol</span> index and absorption <span class="hlt">aerosol</span> optical depth to evaluate the NASA MERRA <span class="hlt">Aerosol</span> Reanalysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buchard, V.; da Silva, A. M.; Colarco, P. R.; Darmenov, A.; Randles, C. A.; Govindaraju, R.; Torres, O.; Campbell, J.; Spurr, R.</p> <p>2015-05-01</p> <p>A radiative transfer interface has been developed to simulate the UV <span class="hlt">aerosol</span> index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) <span class="hlt">aerosol</span> assimilated fields. The purpose of this work is to use the AI and <span class="hlt">aerosol</span> absorption optical depth (AAOD) derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications <span class="hlt">Aerosol</span> Reanalysis (MERRAero). MERRAero is based on a version of the GEOS-5 model that is radiatively coupled to the Goddard Chemistry, <span class="hlt">Aerosol</span>, Radiation, and Transport (GOCART) <span class="hlt">aerosol</span> module and includes assimilation of <span class="hlt">aerosol</span> optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Since AI is dependent on <span class="hlt">aerosol</span> concentration, optical properties and altitude of the <span class="hlt">aerosol</span> <span class="hlt">layer</span>, we make use of complementary observations to fully diagnose the model, including AOD from the Multi-angle Imaging SpectroRadiometer (MISR), <span class="hlt">aerosol</span> retrievals from the <span class="hlt">AErosol</span> RObotic NETwork (AERONET) and attenuated backscatter coefficients from the Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission to ascertain potential misplacement of plume <span class="hlt">height</span> by the model. By sampling dust, biomass burning and pollution events in 2007 we have compared model-produced AI and AAOD with the corresponding OMI products, identifying regions where the model representation of absorbing <span class="hlt">aerosols</span> was deficient. As a result of this study over the Saharan dust region, we have obtained a new set of dust <span class="hlt">aerosol</span> optical properties that retains consistency with the MODIS AOD data that were assimilated, while resulting in better agreement with <span class="hlt">aerosol</span> absorption measurements from OMI. The analysis conducted over the southern African and South American biomass burning regions indicates that revising the spectrally dependent <span class="hlt">aerosol</span> absorption properties in the near-UV region improves the modeled-observed AI comparisons</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3891005','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3891005"><span id="translatedtitle">Double blanket effect caused by two <span class="hlt">layers</span> of black carbon <span class="hlt">aerosols</span> escalates warming in the Brahmaputra River Valley</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rahul, P. R. C.; Bhawar, R. L.; Ayantika, D. C.; Panicker, A. S.; Safai, P. D.; Tharaprabhakaran, V.; Padmakumari, B.; Raju, M. P.</p> <p>2014-01-01</p> <p>First ever 3-day aircraft observations of vertical profiles of Black Carbon (BC) were obtained during the Cloud <span class="hlt">Aerosol</span> Interaction and Precipitation Enhancement Experiment (CAIPEEX) conducted on 30th August, 4th and 6th September 2009 over Guwahati (26°11′N, 91°44′E), the largest metropolitan city in the Brahmaputra River Valley (BRV) region. The results revealed that apart from the surface/near surface loading of BC due to anthropogenic processes causing a heating of 2 K/day, the large-scale Walker and Hadley atmospheric circulations associated with the Indian summer monsoon help in the formation of a second <span class="hlt">layer</span> of black carbon in the upper atmosphere, which generates an upper atmospheric heating of ~2 K/day. Lofting of BC <span class="hlt">aerosols</span> by these large-scale circulating atmospheric cells to the upper atmosphere (4–6 Km) could also be the reason for extreme climate change scenarios that are being witnessed in the BRV region. PMID:24419075</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990004378','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990004378"><span id="translatedtitle">Impact of Tropospheric <span class="hlt">Aerosol</span> Absorption on Ozone Retrieval from buv Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Torres, O.; Bhartia, P. K.</p> <p>1998-01-01</p> <p>The impact of tropospheric <span class="hlt">aerosols</span> on the retrieval of column ozone amounts using spaceborne measurements of backscattered ultraviolet radiation is examined. Using radiative transfer calculations, we show that uv-absorbing desert dust may introduce errors as large as 10% in ozone column amount, depending on the <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span> and optical depth. Smaller errors are produced by carbonaceous <span class="hlt">aerosols</span> that result from biomass burning. Though the error is produced by complex interactions between ozone absorption (both stratospheric and tropospheric), <span class="hlt">aerosol</span> scattering, and <span class="hlt">aerosol</span> absorption, a surprisingly simple correction procedure reduces the error to about 1%, for a variety of <span class="hlt">aerosols</span> and for a wide range of <span class="hlt">aerosol</span> loading. Comparison of the corrected TOMS data with operational data indicates that though the zonal mean total ozone derived from TOMS are not significantly affected by these errors, localized affects in the tropics can be large enough to seriously affect the studies of tropospheric ozone that are currently undergoing using the TOMS data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ACPD....921785R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ACPD....921785R"><span id="translatedtitle">Absorption Angstrom Exponent in AERONET and related data as an indicator of <span class="hlt">aerosol</span> composition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Russell, P. B.; Bergstrom, R. W.; Shinozuka, Y.; Clarke, A. D.; Decarlo, P. F.; Jimenez, J. L.; Livingston, J. M.; Redemann, J.; Holben, B.; Dubovik, O.; Strawa, A.</p> <p>2009-10-01</p> <p>Recent results from diverse air, ground, and laboratory studies using both radiometric and in situ techniques show that the fractions of black carbon, organic matter, and mineral dust in atmospheric <span class="hlt">aerosols</span> determine the wavelength dependence of absorption (expressed as Absorption Angstrom Exponent, or AAE). Taken together, these results hold promise of improving information on <span class="hlt">aerosol</span> composition from remote measurements. The purpose of this paper is to show that AAE values for <span class="hlt">Aerosol</span> Robotic Network (AERONET) retrievals from Sun-sky measurements describing the full <span class="hlt">aerosol</span> vertical column are also strongly correlated with <span class="hlt">aerosol</span> composition or type. In particular, we find AAE values near 1 (the theoretical value for black carbon) for AERONET-measured <span class="hlt">aerosol</span> columns dominated by urban-industrial <span class="hlt">aerosol</span>, larger AAE values for biomass burning <span class="hlt">aerosols</span>, and the largest AAE values for Sahara dust <span class="hlt">aerosols</span>. Ambiguities in <span class="hlt">aerosol</span> composition or mixtures thereof, resulting from intermediate AAE values, can be reduced via cluster analyses that supplement AAE with other variables, for example Extinction Angstrom Exponent (EAE), which is an indicator of particle size. Together with previous results, these results strengthen prospects for determining <span class="hlt">aerosol</span> composition from space, for example using the Glory <span class="hlt">Aerosol</span> Polarimetry Sensor (APS), which promises retrievals of multiwavelength single-scattering albedo (SSA) and <span class="hlt">aerosol</span> optical depth (and therefore <span class="hlt">aerosol</span> absorption optical depth (AAOD) and AAE), as well as shape and other <span class="hlt">aerosol</span> properties. Cluster analyses promise additional information content, for example by using the Ozone Monitoring Instrument (OMI) to add AAOD in the near ultraviolet and CALIPSO <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">heights</span> to reduce <span class="hlt">height</span>-absorption ambiguity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/990743','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/990743"><span id="translatedtitle">A Simple Apparatus for the Injection of Lithium <span class="hlt">Aerosol</span> into the Scrape-Off <span class="hlt">Layer</span> of Fusion Research Devices</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>D. K. Mansfield, A.L Roquemore, H. Schneider, J. Timberlake, H. Kugel, M.G. Bell and the NSTX Research Team</p> <p>2010-10-11</p> <p>A simple device has been developed to deposit elemental lithium onto plasma facing components in the National Spherical Torus Experiment. Deposition is accomplished by dropping lithium powder into the plasma column. Once introduced, lithium particles quickly become entrained in scrape-off <span class="hlt">layer</span> flow as an evaporating <span class="hlt">aerosol</span>. Particles are delivered through a small central aperture in a computer-controlled resonating piezoelectric disk on which the powder is supported. The device has been used to deposit lithium both during discharges as well as prior to plasma breakdown. Clear improvements to plasma performance have been demonstrated. The use of this apparatus provides flexibility in the amount and timing of lithium deposition and, therefore, may benefit future fusion research devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A11B0051W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A11B0051W"><span id="translatedtitle">The VOCALS Regional Experiment: <span class="hlt">Aerosol</span>-Cloud-Precipitation Interactions in Marine Boundary <span class="hlt">Layer</span> Cloud</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wood, R.</p> <p>2012-12-01</p> <p>Robert Wood, C.S. Bretherton, C. R. Mechoso, R. A. Weller, B. J. Huebert, H. Coe, B. A. Albrecht, P. H. Daum, D. Leon, A. Clarke, P. Zuidema, C. W. Fairall, G. Allen, S. deSzoeke, G. Feingold, J. Kazil, S. Yuter, R. George, A. Berner, C. Terai, G. Painter, H. Wang, M. Wyant, D. Mechem The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) is an international field program designed to make observations of poorly understood but critical components of the coupled climate system of the southeast Pacific (SEP), a region dominated by strong coastal upwelling, extensive cold SSTs, and home to the largest subtropical stratocumulus deck on Earth. VOCALS-REx took place during October and November 2008 and involved five research aircraft, two ships and two surface sites in northen Chile. A central theme of VOCALS-REx is the improved understanding of links between <span class="hlt">aerosols</span>, clouds and precipitation and their impacts on marine stratocumulus radiative properties. In this presentation, we will present a synthesis of results from VOCALS-REx focusing on the following questions: (a) how are <span class="hlt">aerosols</span>, clouds and precipitation inter-related in the SEP region? (b) what microphysical-macrophysical interactions are necessary for the formation and maintenance of open cells? (c) how do cloud and MBL properties change across the strong microphysical gradients from the South American coast to the remote ocean?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1159525','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1159525"><span id="translatedtitle">Clouds, <span class="hlt">Aerosol</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span>: Analysis of Results from the ARM Mobile Facility Deployment to the Azores (2009/2010)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wood, Robert</p> <p>2013-05-31</p> <p>The project focuses upon dataset analysis and synthesis of datasets from the AMF deployment entitled “Clouds, <span class="hlt">Aerosols</span>, and Precipitation in the Marine Boundary <span class="hlt">Layer</span> (CAP-MBL)” at Graciosa Island in the Azores. Wood is serving a PI for this AMF deployment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1171944','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1171944"><span id="translatedtitle">Planetary Boundary <span class="hlt">Layer</span> from AERI and MPL</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sawyer, Virginia</p> <p>2014-02-13</p> <p>The distribution and transport of <span class="hlt">aerosol</span> emitted to the lower troposphere is governed by the <span class="hlt">height</span> of the planetary boundary <span class="hlt">layer</span> (PBL), which limits the dilution of pollutants and influences boundary-<span class="hlt">layer</span> convection. Because radiative heating and cooling of the surface strongly affect the PBL top <span class="hlt">height</span>, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level <span class="hlt">aerosol</span> transport makes <span class="hlt">aerosol</span> concentration an effective proxy for PBL <span class="hlt">height</span>: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-<span class="hlt">layer</span> air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL <span class="hlt">heights</span> from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL <span class="hlt">heights</span> can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-<span class="hlt">layer</span> processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19780063529&hterms=volcan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dvolcan','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780063529&hterms=volcan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dvolcan"><span id="translatedtitle">Post-volcanic stratospheric <span class="hlt">aerosol</span> decay as measured by lidar</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mccormick, M. P.; Chu, W. P.; Fuller, W. H., Jr.; Swissler, T. J.</p> <p>1978-01-01</p> <p>The paper summarizes and discusses results of lidar observations, at Hampton (Virginia), of the stratospheric <span class="hlt">aerosol</span> vertical distribution for a period of 22 months (October 1974 to July 1976) after the volcanic eruption of the Volcan de Fuego in Guatemala. Data are presented in terms of lidar scattering ratio, vertically integrated <span class="hlt">aerosol</span> backscattering, <span class="hlt">layer</span> structure and location, and rawinsonde temperature profiles as a function of time. The results reveal a sudden increase in the stratospheric <span class="hlt">aerosol</span> content after the volcanic eruption as well as its subsequent decline. There exists a high degree of correlation between the integrated <span class="hlt">aerosol</span> backscattering and the tropopause <span class="hlt">height</span> such that as one decreases the other increases and vice versa. Rapid decay of the stratospheric <span class="hlt">aerosol</span> is found to occur over the late winter to early spring period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AMT.....7.3399K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AMT.....7.3399K"><span id="translatedtitle">Verification and application of the extended spectral deconvolution algorithm (SDA+) methodology to estimate <span class="hlt">aerosol</span> fine and coarse mode extinction coefficients in the marine boundary <span class="hlt">layer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaku, K. C.; Reid, J. S.; O'Neill, N. T.; Quinn, P. K.; Coffman, D. J.; Eck, T. F.</p> <p>2014-10-01</p> <p>The spectral deconvolution algorithm (SDA) and SDA+ (extended SDA) methodologies can be employed to separate the fine and coarse mode extinction coefficients from measured total <span class="hlt">aerosol</span> extinction coefficients, but their common use is currently limited to AERONET (<span class="hlt">AErosol</span> RObotic NETwork) <span class="hlt">aerosol</span> optical depth (AOD). Here we provide the verification of the SDA+ methodology on a non-AERONET <span class="hlt">aerosol</span> product, by applying it to fine and coarse mode nephelometer and particle soot absorption photometer (PSAP) data sets collected in the marine boundary <span class="hlt">layer</span>. Using data sets collected on research vessels by NOAA-PMEL(National Oceanic and Atmospheric Administration - Pacific Marine Environmental Laboratory), we demonstrate that with accurate input, SDA+ is able to predict the fine and coarse mode scattering and extinction coefficient partition in global data sets representing a range of <span class="hlt">aerosol</span> regimes. However, in low-extinction regimes commonly found in the clean marine boundary <span class="hlt">layer</span>, SDA+ output accuracy is sensitive to instrumental calibration errors. This work was extended to the calculation of coarse and fine mode scattering coefficients with similar success. This effort not only verifies the application of the SDA+ method to in situ data, but by inference verifies the method as a whole for a host of applications, including AERONET. Study results open the door to much more extensive use of nephelometers and PSAPs, with the ability to calculate fine and coarse mode scattering and extinction coefficients in field campaigns that do not have the resources to explicitly measure these values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A41G0135B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A41G0135B"><span id="translatedtitle">Separating Dust Mixtures and Other External <span class="hlt">Aerosol</span> Mixtures Using Airborne High Spectral Resolution Lidar Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burton, S. P.; Ferrare, R. A.; Vaughan, M.; Hostetler, C. A.; Rogers, R. R.; Hair, J. W.; Cook, A. L.; Harper, D. B.</p> <p>2013-12-01</p> <p>Knowledge of <span class="hlt">aerosol</span> type is important for source attribution and for determining the magnitude and assessing the consequences of <span class="hlt">aerosol</span> radiative forcing. The NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL-1) has acquired considerable datasets of both <span class="hlt">aerosol</span> extensive parameters (e.g. <span class="hlt">aerosol</span> optical depth) and intensive parameters (e.g. <span class="hlt">aerosol</span> depolarization ratio, lidar ratio) that can be used to infer <span class="hlt">aerosol</span> type. An <span class="hlt">aerosol</span> classification methodology has been used extensively to classify HSRL-1 <span class="hlt">aerosol</span> measurements of different <span class="hlt">aerosol</span> types including dust, smoke, urban pollution, and marine <span class="hlt">aerosol</span>. However, atmospheric <span class="hlt">aerosol</span> is frequently not a single pure type, but instead occurs as a mixture of types, and this mixing affects the optical and radiative properties of the <span class="hlt">aerosol</span>. Here we present a comprehensive and unified set of rules for characterizing external mixtures using several key <span class="hlt">aerosol</span> intensive parameters: extinction-to-backscatter ratio (i.e. lidar ratio), backscatter color ratio, and depolarization ratio. Our mixing rules apply not just to the scalar values of <span class="hlt">aerosol</span> intensive parameters, but to multi-dimensional normal distributions with variance in each measurement dimension. We illustrate the applicability of the mixing rules using examples of HSRL-1 data where mixing occurred between different <span class="hlt">aerosol</span> types, including advected Saharan dust mixed with the marine boundary <span class="hlt">layer</span> in the Caribbean Sea and locally generated dust mixed with urban pollution in the Mexico City surroundings. For each of these cases we infer a time-<span class="hlt">height</span> cross section of mixing ratio along the flight track and we partition <span class="hlt">aerosol</span> extinction into portions attributed to the two pure types. Since multiple <span class="hlt">aerosol</span> intensive parameters are measured and included in these calculations, the techniques can also be used for cases without significant depolarization (unlike similar work by earlier researchers), and so a third example of a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20090001329&hterms=stratosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dstratosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20090001329&hterms=stratosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dstratosphere"><span id="translatedtitle">Single-Particle Measurements of Midlatitude Black Carbon and Light-Scattering <span class="hlt">Aerosols</span> from the Boundary <span class="hlt">Layer</span> to the Lower Stratosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schwartz, J. P.; Gao, R. S.; Fahey, D. W.; Thomson, D. S.; Watts, L. A.; Wilson, J. C.; Reeves, J. M.; Darbeheshti, M.; Baumgardner, D. G.; Kok, G. L.; Chung, S. H.; Schulz, M.; Hendricks, J.; Lauer, A.; Kaercher, B.; Slowik, J. G.; Rosenlof, K. H.; Thompson, T. L.; Langford, A. O.; Loewenstein, M.; Aikin, K. C.</p> <p>2006-01-01</p> <p>A single-particle soot photometer (SP2) was flown on a NASA WB-57F high-altitude research aircraft in November 2004 from Houston, Texas. The SP2 uses laser-induced incandescence to detect individual black carbon (BC) particles in an air sample in the mass range of approx.3-300 fg (approx.0.15-0.7 microns volume equivalent diameter). Scattered light is used to size the remaining non-BC <span class="hlt">aerosols</span> in the range of approx.0.17-0.7 microns diameter. We present profiles of both <span class="hlt">aerosol</span> types from the boundary <span class="hlt">layer</span> to the lower stratosphere from two midlatitude flights. Results for total <span class="hlt">aerosol</span> amounts in the size range detected by the SP2 are in good agreement with typical particle spectrometer measurements in the same region. All ambient incandescing particles were identified as BC because their incandescence properties matched those of laboratory-generated BC <span class="hlt">aerosol</span>. Approximately 40% of these BC particles showed evidence of internal mixing (e.g., coating). Throughout profiles between 5 and 18.7 km, BC particles were less than a few percent of total <span class="hlt">aerosol</span> number, and black carbon <span class="hlt">aerosol</span> (BCA) mass mixing ratio showed a constant gradient with altitude above 5 km. SP2 data was compared to results from the ECHAM4/MADE and LmDzT-INCA global <span class="hlt">aerosol</span> models. The comparison will help resolve the important systematic differences in model <span class="hlt">aerosol</span> processes that determine BCA loadings. Further intercomparisons of models and measurements as presented here will improve the accuracy of the radiative forcing contribution from BCA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT........27Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT........27Z"><span id="translatedtitle">Observational and numerical studies of the boundary <span class="hlt">layer</span>, cloud, and <span class="hlt">aerosol</span> variability in the southeast Pacific coastal marine stratocumulus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Xue</p> <p></p> <p>This dissertation investigates the impacts of meteorological factors and <span class="hlt">aerosol</span> indirect effects on the costal marine stratocumulus (Sc) variations in the southeast Pacific, a region that has been largely unexplored and is a major challenge of the modeling community, through both observational and numerical studies. This study provides a unique dataset for documenting the characteristics of the marine Sc-topped BL off the coast of Northern Chile. The observational study shows that the boundary <span class="hlt">layer</span> (BL) over this region was well mixed and topped by a thin and non-drizzling Sc <span class="hlt">layer</span> on days synoptically-quiescent with little variability between this region and the coast. The surface wind, the surface fluxes and the BL turbulence appeared to be weaker than those over other ocean regions where stratocumulus clouds exist. The weaker turbulence in the BL may contribute to a relatively low entrainment rate calculated from the near cloud top fluxes. This in-situ data set can help us better understand cloud processes within this coastal regime, and also be valuable for the calibration of the satellite retrievals and the evaluation of numerical models operating at a variety of scales. A strong positive correlation between the liquid water path (LWP) and the cloud condensation nuclei (CCN) was observed under similar boundary <span class="hlt">layer</span> conditions. This correlation cannot be explained by some of the hypotheses based on previous modeling studies. The satellite retrievals obtained upstream one day prior to the flight observations reveal some sign that the clouds under the high CCN concentrations have minimal LWP loss due to precipitation suppression effects. The results from large eddy simulations with a two-momentum bulk microphysics scheme under different idealized environment scenarios based on aircraft observations indicate that (1) the simulated Sc responds more quickly to changes in large-scale subsidence than to those changes in surface fluxes, free-tropospheric humidity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRD..117.6304A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRD..117.6304A"><span id="translatedtitle">Isotopic constraints on the formation pathways of sulfate <span class="hlt">aerosol</span> in the marine boundary <span class="hlt">layer</span> of the subtropical northeast Atlantic Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alexander, B.; Allman, D. J.; Amos, H. M.; Fairlie, T. D.; Dachs, J.; Hegg, Dean A.; Sletten, Ronald S.</p> <p>2012-03-01</p> <p>We use observations of the oxygen-17 excess of non-sea salt sulfate <span class="hlt">aerosol</span> (Δ17O(nssSO42-)) collected from two ship cruises in the subtropical northeast Atlantic Ocean in August 2006 and February 2007 to quantify the formation pathways of sulfate in the marine boundary <span class="hlt">layer</span> (MBL). The large observed Δ17O(nssSO42-) values up to 7.3‰ suggest a large role for sulfate formation via S(IV) oxidation by O3 in the MBL. Model simulations with the GEOS-Chem global chemical transport model suggest that in-cloud oxidation of S(IV) by O3 represents over one-third (36-37%) of total in-cloud sulfate production on average. A model parameterization accounting for the impacts of sea salt <span class="hlt">aerosol</span> on cloud droplet chemical heterogeneity and resulting impacts on in-cloud sulfate production rates improves the model's agreement with the Δ17O(nssSO42-) observations in the MBL. Including this parameterization in the model had little impact on the global sulfur budget due to the dominant role of continental anthropogenic emissions for global sulfur emissions in the present-day. The large observed Δ17O(nssSO42-) argue against a significant role of hypobromous (HOBr) or hypochlorous (HOCl) acid for sulfate formation in the remote MBL of the wintertime subtropical northeast Atlantic, but S(IV) oxidation by HOBr/HOCl on the order of 20% of total sulfate abundance is consistent with the summertime Δ17O(nssSO42-) observations in the more polluted coastal region of the Iberian Peninsula. Additional measurements of Δ17O(nssSO42-) are needed to quantify sulfate production mechanisms in the MBL over larger spatial and temporal scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.A21I..08C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.A21I..08C"><span id="translatedtitle">Aged Organic <span class="hlt">Aerosol</span> in the Upper Troposphere: Aging of boundary <span class="hlt">layer</span> <span class="hlt">aerosol</span> during and after convective transport and in-situ SOA formation during DC3. (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campuzano Jost, P.; Palm, B. B.; Day, D. A.; Ortega, A. M.; Hayes, P. L.; Jimenez, J. L.; Hodzic, A.; Bela, M. M.; Barth, M. C.; Olson, J. R.; Crawford, J. H.; Brune, W. H.; Pollack, I. B.; Ryerson, T. B.; Blake, D. R.; Wisthaler, A.; Mikoviny, T.</p> <p>2013-12-01</p> <p>While <span class="hlt">aerosol</span> scavenging in deep convection is efficient (comparable to soluble species like formaldehyde), significant transport of submicron <span class="hlt">aerosol</span> was observed repeatedly during storms targeted in the course of the DC3 (Deep Convective Clouds and Chemistry ) campaign. The lofted <span class="hlt">aerosol</span> was mostly organic, and even in fresh outflow was significantly more oxidized than the <span class="hlt">aerosol</span> sampled in the source region of the convection. Organic <span class="hlt">aerosol</span> (OA) sampled in both day-old outflow as well as in the background continental UT was in general significantly more oxidized than OA observed both in the fresh outflow, and in most lower tropospheric <span class="hlt">aerosol</span>. This suggests either fast oxidative chemistry, and/or long residence times in the UT. Some of the potential factors contributing to this fast oxidation will be explored in this talk. A second source of UT OA was observed during several flights where gas-phase organics in the presence of NOx lead to the formation of secondary OA (SOA), including particulate organic nitrate. Most observations of this UT SOA during DC3 were made in fresh outflow. However, a unique opportunity to study the chemistry of this SOA formation in more detail with a box model presented itself in the flight on July 21st, 2012; here an initially near-particle-free UT airmass originating in the wake of a dissolving nighttime mesoscale convective system (MCS) was observed over several hours until new particle growth dominated by OA and particulate nitrate was measured.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BoLMe.157..265B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BoLMe.157..265B"><span id="translatedtitle">Performance Evaluation of the Boundary-<span class="hlt">Layer</span> <span class="hlt">Height</span> from Lidar and the Weather Research and Forecasting Model at an Urban Coastal Site in the North-East Iberian Peninsula</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Banks, Robert F.; Tiana-Alsina, Jordi; Rocadenbosch, Francesc; Baldasano, José M.</p> <p>2015-11-01</p> <p>We evaluate planetary boundary-<span class="hlt">layer</span> (PBL) parametrizations in the Weather Research and Forecasting (WRF) numerical model, with three connected objectives: first, for a 16-year period, we use a cluster analysis algorithm of three-day back-trajectories to determine general synoptic flow patterns over Barcelona, Spain arriving at <span class="hlt">heights</span> of 0.5, 1.5, and 3 km; to represent the lower PBL, upper PBL, and lower free troposphere, respectively. Seven clusters are determined at each arriving altitude. Regional recirculations account for 54 % of the annual total at 0.5 km, especially in summertime. In the second objective, we assess a time-adaptive approach using an extended Kalman filter to estimate PBL <span class="hlt">height</span> from backscatter lidar returns at 1200 UTC ± 30 min for 45 individual days during a seven-year period. PBL <span class="hlt">heights</span> retrieved with this technique are compared with three classic methods used in the literature to estimate PBL <span class="hlt">height</span> from lidar. The methods are validated against PBL <span class="hlt">heights</span> calculated from daytime radiosoundings. Lidar and radiosonde estimated PBL <span class="hlt">heights</span> are classified under objectively-determined synoptic clusters. With the final objective, WRF model-simulated PBL <span class="hlt">heights</span> are validated against lidar estimates using eight unique PBL schemes as inputs. Evaluation of WRF model-simulated PBL <span class="hlt">heights</span> are performed under different synoptic situations. Determination coefficients with lidar estimates indicate the non-local assymetric convective model scheme is the most reliable, with the widely-tested local Mellor-Yamada-Janjic scheme showing the weakest correlations with lidar retrievals. Overall, there is a systematic underestimation of PBL <span class="hlt">height</span> simulated in the WRF model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040031852&hterms=geoscience&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgeoscience','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040031852&hterms=geoscience&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgeoscience"><span id="translatedtitle">Space Borne Cloud and <span class="hlt">Aerosol</span> Measurements by the Geoscience Laser Altimeter System: Initial Results</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spinhirne, James D.; Palm, Steven P.; Hlavka, Dennis L.; Hart, William D.; Mahesh, Ashwin; Welton, Ellsworth J.</p> <p>2003-01-01</p> <p>In January 2003 the Geoscience Laser Altimeter System (GLAS) was successfully launched into orbit. Beginning in March 2003 GLAS will provide global coverage lidar measurement of the <span class="hlt">height</span> distribution of clouds and <span class="hlt">aerosol</span> in the atmosphere for up to five years. The characteristic and value of the unique data will be presented. The instrument is a basic backscatter lidar that operates at two wavelengths, 532 and 1064 nm. The mission data products for atmospheric observations include the calibrated, observed, attenuated backscatter cross section for cloud and <span class="hlt">aerosol</span>; <span class="hlt">height</span> detection for multiple cloud <span class="hlt">layers</span>; planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span>; cirrus and <span class="hlt">aerosol</span> optical depth and the <span class="hlt">height</span> distribution of <span class="hlt">aerosol</span> and cloud scattering cross section profiles. The data is expected to significantly enhance knowledge in several areas of atmospheric science, in particular the distribution, transport and influence of atmospheric <span class="hlt">aerosol</span> and thin clouds. Measurements of the coverage and <span class="hlt">height</span> of polar and cirrus cloud should be significantly more accurate than previous global observations. In March and April 2003, airborne and ground based data verification experiments will be carried out. Initial results from the verification experiments and the first several months of operation will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920059288&hterms=denitrification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddenitrification','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920059288&hterms=denitrification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddenitrification"><span id="translatedtitle">Stratospheric sulfate <span class="hlt">aerosol</span> in and near the Northern Hemisphere polar vortex - The morphology of the sulfate <span class="hlt">layer</span>, multimodal size distributions, and the effect of denitrification</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, J. G.; Stolzenburg, M. R.; Clark, W. E.; Loewenstein, M.; Ferry, G. V.; Chan, K. R.; Kelly, K. K.</p> <p>1992-01-01</p> <p>Measurements were made of stratospheric sulfate <span class="hlt">aerosols</span> using a passive cavity <span class="hlt">aerosol</span> spectrometer and a condensation nucleus counter on a NASA ER-2 aircraft in the Airborne Arctic Stratospheric Experiment of 1989. The problems of representative and accurate sampling and particle evaporation were explicitly addressed in the design of the inlets and reduction of the data. The measurements suggest that the sulfate <span class="hlt">aerosol</span> is bimodal in the polar vortex above the mass mixing ratio maximum in the sulfate <span class="hlt">layer</span>. It appears that a nuclei mode of small, newly formed particles exists in this region. A stronger case is made for a nuclei mode in the upper few kilometers of the troposphere and in the lower few kilometers of the stratosphere. This mode is probably a global phenomenon occurring in all seasons. Comparison of denitrified and nondenitrified air suggests that denitrification removes some of the larger sulfate particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACPD...1531471B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACPD...1531471B"><span id="translatedtitle"><span class="hlt">Aerosol</span> optical properties in the southeastern United States in summer - Part 2: Sensitivity of <span class="hlt">aerosol</span> optical depth to relative humidity and <span class="hlt">aerosol</span> parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brock, C. A.; Wagner, N. L.; Anderson, B. E.; Beyersdorf, A.; Campuzano-Jost, P.; Day, D. A.; Diskin, G. S.; Gordon, T. D.; Jimenez, J. L.; Lack, D. A.; Liao, J.; Markovic, M.; Middlebrook, A. M.; Perring, A. E.; Richardson, M. S.; Schwarz, J. P.; Welti, A.; Ziemba, L. D.; Murphy, D. M.</p> <p>2015-11-01</p> <p>Aircraft observations of meteorological, trace gas, and <span class="hlt">aerosol</span> properties were made between May and September 2013. Regionally representative aggregate vertical profiles of median and interdecile ranges of the measured parameters were constructed from 37 individual aircraft profiles made in the afternoon when a well-mixed boundary <span class="hlt">layer</span> with typical fair-weather cumulus was present (Wagner et al., 2015). We use these 0-4 km aggregate profiles and a simple model to calculate the sensitivity of <span class="hlt">aerosol</span> optical depth (AOD) to changes in dry <span class="hlt">aerosol</span> mass, relative humidity, mixed <span class="hlt">layer</span> <span class="hlt">height</span>, the central diameter and width of the particle size distribution, hygroscopicity, and dry and wet refractive index, while holding the other parameters constant. The calculated sensitivity is a result of both the intrinsic sensitivity and the observed range of variation of these parameters. These observationally based sensitivity studies indicate that the relationship between AOD and dry <span class="hlt">aerosol</span> mass in these conditions in the southeastern US can be highly variable and is especially sensitive to relative humidity (RH). For example, calculated AOD ranged from 0.137 to 0.305 as the RH was varied between the 10th and 90th percentile profiles with dry <span class="hlt">aerosol</span> mass held constant. Calculated AOD was somewhat less sensitive to <span class="hlt">aerosol</span> hygroscopicity, mean size, and geometric standard deviation, σg. However, some chemistry-climate models prescribe values of σg substantially larger than we or others observe, leading to potential high biases in model-calculated AOD of ~ 25 %. Finally, AOD was least sensitive to observed variations in dry and wet <span class="hlt">aerosol</span> refractive index and to changes in the <span class="hlt">height</span> of the well-mixed surface <span class="hlt">layer</span>. We expect these findings to be applicable to other moderately polluted and background continental airmasses in which an accumulation mode between 0.1-0.5 μm diameter dominates <span class="hlt">aerosol</span> extinction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.5009B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.5009B&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Aerosol</span> optical properties in the southeastern United States in summer - Part 2: Sensitivity of <span class="hlt">aerosol</span> optical depth to relative humidity and <span class="hlt">aerosol</span> parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brock, Charles A.; Wagner, Nicholas L.; Anderson, Bruce E.; Beyersdorf, Andreas; Campuzano-Jost, Pedro; Day, Douglas A.; Diskin, Glenn S.; Gordon, Timothy D.; Jimenez, Jose L.; Lack, Daniel A.; Liao, Jin; Markovic, Milos Z.; Middlebrook, Ann M.; Perring, Anne E.; Richardson, Matthews S.; Schwarz, Joshua P.; Welti, Andre; Ziemba, Luke D.; Murphy, Daniel M.</p> <p>2016-04-01</p> <p>Aircraft observations of meteorological, trace gas, and <span class="hlt">aerosol</span> properties were made between May and September 2013 in the southeastern United States (US). Regionally representative aggregate vertical profiles of median and interdecile ranges of the measured parameters were constructed from 37 individual aircraft profiles made in the afternoon when a well-mixed boundary <span class="hlt">layer</span> with typical fair-weather cumulus was present (Wagner et al., 2015). We use these 0-4 km aggregate profiles and a simple model to calculate the sensitivity of <span class="hlt">aerosol</span> optical depth (AOD) to changes in dry <span class="hlt">aerosol</span> mass, relative humidity, mixed-<span class="hlt">layer</span> <span class="hlt">height</span>, the central diameter and width of the particle size distribution, hygroscopicity, and dry and wet refractive index, while holding the other parameters constant. The calculated sensitivity is a result of both the intrinsic sensitivity and the observed range of variation in these parameters. These observationally based sensitivity studies indicate that the relationship between AOD and dry <span class="hlt">aerosol</span> mass in these conditions in the southeastern US can be highly variable and is especially sensitive to relative humidity (RH). For example, calculated AOD ranged from 0.137 to 0.305 as the RH was varied between the 10th and 90th percentile profiles with dry <span class="hlt">aerosol</span> mass held constant. Calculated AOD was somewhat less sensitive to <span class="hlt">aerosol</span> hygroscopicity, mean size, and geometric standard deviation, σg. However, some chemistry-climate models prescribe values of σg substantially larger than we or others observe, leading to potential high biases in model-calculated AOD of ˜ 25 %. Finally, AOD was least sensitive to observed variations in dry and wet <span class="hlt">aerosol</span> refractive index and to changes in the <span class="hlt">height</span> of the well-mixed surface <span class="hlt">layer</span>. We expect these findings to be applicable to other moderately polluted and background continental air masses in which an accumulation mode between 0.1-0.5 µm diameter dominates <span class="hlt">aerosol</span> extinction.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006AtmEn..40.6245E&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006AtmEn..40.6245E&link_type=ABSTRACT"><span id="translatedtitle">Size distribution, composition and origin of the submicron <span class="hlt">aerosol</span> in the marine boundary <span class="hlt">layer</span> during the eastern Mediterranean "SUB-AERO" experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eleftheriadis, K.; Colbeck, I.; Housiadas, C.; Lazaridis, M.; Mihalopoulos, N.; Mitsakou, C.; Smolík, J.; Ždímal, V.</p> <p></p> <p>A period of intensive physical and chemical <span class="hlt">aerosol</span> characterisation measurements was held over 5 days during July 2000 as part of the European SUB-AERO experiment.. Concurrent measurements were performed at the Finokalia remote coastal site on the island of Crete (Greece) and onboard the R/V " Aegaeon" which cruised in south part of the Aegean Sea northwards of Crete. The objective of the study was to investigate the spatial and temporal variability of microphysical parameters of the submicron <span class="hlt">aerosol</span> and their dependence on airmass origin and chemical composition. The results reflect the submicron <span class="hlt">aerosol</span> properties during airmass transport from the north including Europe and the Balkans and are in line with other studies on the <span class="hlt">aerosol</span> properties of polluted continental air entering the marine boundary <span class="hlt">layer</span> (MBL). Concentrations of submicron particulate matter (PM) mass were relatively higher at sea (20 μg m -3) compared to the coastal site (16 μg m -3). Concentrations of both organic carbon and sulphate, being the major water soluble component, were also higher at sea than at land. The high concentrations of ammonium and those of the water soluble organics, such as oxalate, can be attributed to emissions from mainland forest fires. The submicron <span class="hlt">aerosol</span> number size distribution was unimodal with mobility mean diameters ( dg) ranging from 98 to 144 μm and standard deviations ( σg) from 1.56 to 1.9. <span class="hlt">Aerosol</span> number concentrations at Finokalia were at least 50% lower especially when R/V Aegaeon sampled polluted air, but the modal parameters of the size distribution were very similar ( dg: 111-120, σg: 1.55-1.91). The surface MBL, under these conditions, was an <span class="hlt">aerosol</span> rich environment where <span class="hlt">aerosol</span> particles were transported both by the surface wind, advected from higher <span class="hlt">layers</span>, chemically processed by interactions with gaseous precursors and physically altered by water vapour. The number to volume ratio for the submicrometer <span class="hlt">aerosol</span> fraction reflected the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15381321','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15381321"><span id="translatedtitle">Seasonal variations of <span class="hlt">aerosol</span> residence time in the lower atmospheric boundary <span class="hlt">layer</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ahmed, A A; Mohamed, A; Ali, A E; Barakat, A; Abd El-Hady, M; El-Hussein, A</p> <p>2004-01-01</p> <p>During a one year period, from Jan. 2002 up to Dec. 2002, approximately 130 air samples were analyzed to determine the atmospheric air activity concentrations of short- and long-lived (222Rn) decay products 214Pb and 210Pb. The samples were taken by using a single-filter technique and gamma-spectrometry was applied to determine the activity concentrations. A seasonal fluctuation in the concentration of 214Pb and 210Pb in surface air was observed. The activity concentrations of both radionuclides were observed to be relatively higher during the winter/autumn season than in spring/summer season. The mean activity concentration of 214Pb and 210Pb within the whole year was found to be 1.4+/-0.27 Bq m(-3) and 1.2+/-0.15 mBq m(-3), respectively. Different 210Pb:214Pb activity ratios during the year varied between 1.78 x 10(-4) and 1.6 x 10(-3) with a mean value of 8.9 x 10(-4) +/- 7.6 x 10(-5). From the ratio between the activity concentrations of the radon decay products 214Pb and 210Pb a mean residence time (MRT) of <span class="hlt">aerosol</span> particles in the atmosphere of about 10.5+/-0.91 d could be estimated. The seasonal variation pattern shows relatively higher values of MRT in spring/summer season than in winter/autumn season. The MRT data together with relative humidity (RH), air temperature (T) and wind speed (WS), were used for a comprehensive regression analysis of its seasonal variation in the atmospheric air. PMID:15381321</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AtmEn.140..605W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AtmEn.140..605W&link_type=ABSTRACT"><span id="translatedtitle">Research on <span class="hlt">aerosol</span> profiles and parameterization scheme in Southeast China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Gang; Deng, Tao; Tan, Haobo; Liu, Xiantong; Yang, Honglong</p> <p>2016-09-01</p> <p>The vertical distribution of the <span class="hlt">aerosol</span> extinction coefficient serves as a basis for evaluating <span class="hlt">aerosol</span> radiative forcing and air quality modeling. In this study, MODIS AOD data and ground-based lidar extinction coefficients were employed to verify 6 years (2009-2014) <span class="hlt">aerosol</span> extinction data obtained via CALIOP for Southeast China. The objective was mainly to provide the parameterization scheme of annual and seasonal <span class="hlt">aerosol</span> extinction profiles. The results showed that the horizontal and vertical distributions of CALIOP extinction data were highly accurate in Southeast China. The annual average AOD below 2 km accounted for 64% of the total <span class="hlt">layer</span>, with larger proportions observed in winter (80%) and autumn (80%) and lower proportions observed in summer (70%) and spring (59%). The AOD was maximum in the spring (0.58), followed by the autumn and winter (0.44), and reached a minimum in the summer (0.40). The near-surface extinction coefficient increased from summer, spring, autumn and winter, in that order. The Elterman profile is obviously lower than the profiles observed by CALIOP in Southeast China. The annual average and seasonal <span class="hlt">aerosol</span> profiles showed an exponential distribution, and could be divided into two sections. Two sections exponential fitting was used in the parameterization scheme. In the first section, the <span class="hlt">aerosol</span> scale <span class="hlt">height</span> reached 2200 m with a maximum (3,500 m) in summer and a minimum (1,230 m) in winter, which meant that the <span class="hlt">aerosol</span> extinction decrease with <span class="hlt">height</span> slower in summer, but more rapidly in winter. In second section, the <span class="hlt">aerosol</span> scale <span class="hlt">height</span> was maximum in spring, which meant that the higher <span class="hlt">aerosol</span> diffused in spring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1229987','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1229987"><span id="translatedtitle">Wave like signatures in <span class="hlt">aerosol</span> optical depth and associated radiative impacts over the central Himalayan region</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shukla, K. K.; Phanikumar, D. V.; Kumar, K.  Niranjan; Reddy, Kishore; Kotamarthi, V. R.; Newsom, Rob K.; Ouarda, Taha B. M. J.</p> <p>2015-10-01</p> <p>In this study, we present a case study on 16 October 2011 to show the first observational evidence of the influence of short period gravity waves in <span class="hlt">aerosol</span> transport during daytime over the central Himalayan region. The Doppler lidar data has been utilized to address the daytime boundary <span class="hlt">layer</span> evolution and related <span class="hlt">aerosol</span> dynamics over the site. Mixing <span class="hlt">layer</span> <span class="hlt">height</span> is estimated by wavelet covariance transform method and found to be ~ 0.7 km, AGL. <span class="hlt">Aerosol</span> optical depth observations during daytime revealed an asymmetry showing clear enhancement during afternoon hours as compared to forenoon. Interestingly, Fourier and wavelet analysis of vertical velocity and attenuated backscatter showed similar 50-90 min short period gravity wave signatures during afternoon hours. Moreover, our observations showed that gravity waves are dominant within the boundary <span class="hlt">layer</span> implying that the daytime boundary <span class="hlt">layer</span> dynamics is playing a vital role in transporting the <span class="hlt">aerosols</span> from surface to the top of the boundary <span class="hlt">layer</span>. Similar modulations are also evident in surface parameters like temperature, relative humidity and wind speed indicating these waves are associated with the dynamical aspects over Himalayan region. Finally, time evolution of range-23 <span class="hlt">height</span> indicator snapshots during daytime showed strong upward velocities especially during afternoon hours implying that convective processes through short period gravity waves plays a significant role in transporting <span class="hlt">aerosols</span> from the nearby valley region to boundary <span class="hlt">layer</span> top over the site. These observations also establish the importance of wave induced daytime convective boundary <span class="hlt">layer</span> dynamics in the lower Himalayan region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730004894','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730004894"><span id="translatedtitle">Mixing-<span class="hlt">height</span> measurement by lidar, particle counter, and rawinsonde in the Williamette Valley, Oregon</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mccormick, M. P.; Melfi, S. H.; Olsson, L. E.; Tuft, W. L.; Elliott, W. P.; Egami, R.</p> <p>1972-01-01</p> <p>The feasibility of using laser radar (lidar) to measure the spatial distribution of <span class="hlt">aerosols</span> and water vapor in the earth's mixing or boundary <span class="hlt">layer</span> is shown. From these data the important parameter of actual mixing <span class="hlt">height</span> was determined, that is, the maximum <span class="hlt">height</span> to which particulate pollutants actually mix. Data are shown for simultaneous lidar, rawinsonde, and aircraft-mounted condensation nuclei counter and temperature measurements. The synoptic meteorology is also presented. The Williamette Valley, Oregon, was chosen for the measurements because of its unique combination of meteorology, terrain, and pollutant source, along with an ongoing Oregon State University study of the natural ventilation of this valley.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080024015','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080024015"><span id="translatedtitle"><span class="hlt">Aerosol</span> Profile Measurements from the NASA Langley Research Center Airborne High Spectral Resolution Lidar</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Obland, Michael D.; Hostetler, Chris A.; Ferrare, Richard A.; Hair, John W.; Roers, Raymond R.; Burton, Sharon P.; Cook, Anthony L.; Harper, David B.</p> <p>2008-01-01</p> <p>Since achieving first light in December of 2005, the NASA Langley Research Center (LaRC) Airborne High Spectral Resolution Lidar (HSRL) has been involved in seven field campaigns, accumulating over 450 hours of science data across more than 120 flights. Data from the instrument have been used in a variety of studies including validation and comparison with the Cloud- <span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite mission, <span class="hlt">aerosol</span> property retrievals combining passive and active instrument measurements, <span class="hlt">aerosol</span> type identification, <span class="hlt">aerosol</span>-cloud interactions, and cloud top and planetary boundary <span class="hlt">layer</span> (PBL) <span class="hlt">height</span> determinations. Measurements and lessons learned from the HSRL are leading towards next-generation HSRL instrument designs that will enable even further studies of <span class="hlt">aerosol</span> intensive and extensive parameters and the effects of <span class="hlt">aerosols</span> on the climate system. This paper will highlight several of the areas in which the NASA Airborne HSRL is making contributions to climate science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1711403G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1711403G"><span id="translatedtitle"><span class="hlt">Aerosol</span> profiling by calibrated ceilometer data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geiß, Alexander; Wiegner, Matthias</p> <p>2015-04-01</p> <p>Recently, networks of automated single-wavelength backscatter lidars ("ceilometers") were implemented, primarily by weather services. As a consequence, the potential of ceilometers to quantitatively determine the spatiotemporal distribution of atmospheric <span class="hlt">aerosols</span> was investigated, to derive mixing <span class="hlt">layer</span> <span class="hlt">heights</span> for air quality studies and to assess optical properties. The main issues are the limited signal-to-noise ratio and the inherent problems of the calibration. We have studied several approaches for calibrating ceilometers, based on different numerical solutions and on auxiliary data of different remote sensing techniques. As a result, the backscatter coefficient can be determined with a relative accuracy of typically 10% and a time resolution in the order of 5 minutes. This parameter is used to estimate the mixing <span class="hlt">layer</span> <span class="hlt">height</span> by applying different techniques of averaging and pattern recognition. In this context, it is assumed that <span class="hlt">aerosols</span> are a good tracer for the thermodynamic stratification of the troposphere. Our algorithm is fully automated and was tested for several commercially available ceilometers. For this purpose, a simplified version for non-calibrated ceilometers, based on the so called range corrected signal, was additionally developed. We used data of the CHM15k-x ceilometer (manufactured by Jenoptik) from more than 5 years of continuous operation by the LMU-MIM in Munich (Germany) to establish climatologies of mixing <span class="hlt">layer</span> <span class="hlt">heights</span> (MLH), cloud cover, cloud <span class="hlt">heights</span> and vertical profiles of the backscatter coefficient. Among others, the mean diurnal cycle and the interannual variability of the MLH for different months were determined. Ceilometer derived MLH were also used to validate different parameterization of chemistry transport models and to validate forecasts of the dispersion of <span class="hlt">aerosol</span> <span class="hlt">layers</span>. For the latter applications backscatter coefficients are required. That means, a calibration of the ceilometers is mandatory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960027548','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960027548"><span id="translatedtitle">Lidar measurements of boundary <span class="hlt">layers</span>, <span class="hlt">aerosol</span> scattering and clouds during project FIFE</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Eloranta, Edwin W. (Principal Investigator)</p> <p>1995-01-01</p> <p>A detailed account of progress achieved under this grant funding is contained in five journal papers. The titles of these papers are: The calculation of area-averaged vertical profiles of the horizontal wind velocity using volume imaging lidar data; Volume imaging lidar observation of the convective structure surrounding the flight path of an instrumented aircraft; Convective boundary <span class="hlt">layer</span> mean depths, cloud base altitudes, cloud top altitudes, cloud coverages, and cloud shadows obtained from Volume Imaging Lidar data; An accuracy analysis of the wind profiles calculated from Volume Imaging Lidar data; and Calculation of divergence and vertical motion from volume-imaging lidar data. Copies of these papers form the body of this report.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9876E..3GC','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9876E..3GC"><span id="translatedtitle">Analysis of <span class="hlt">aerosol</span> properties derived from sun photometer and lidar over Dunhuang radiometric calibration site</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Lin; Jing, Yingying; Zhang, Peng; Hu, Xiuqing</p> <p>2016-05-01</p> <p>Duhuang site has been selected as China Radiation Calibration Site (CRCS) for Remote Sensing Satellite Sensors since 1996. With the economic development of Dunhuang city, the ambient of the radiation calibration field has changed in recent years. Taking into account the key role of <span class="hlt">aerosol</span> in radiometric calibration, it is essential to investigate the <span class="hlt">aerosol</span> optical properties over Dunhuang radiometric calibration site. In this paper, the CIMEL sun photometer (CE-318) and Mie-scattering Lidar are simultaneously used to measure <span class="hlt">aerosol</span> optical properties in Dunhuang site. Data from <span class="hlt">aerosol</span>-bands of sun photometer are used in a Langley method to determine spectral optical depths of <span class="hlt">aerosol</span>. And Lidar is utilized to obtain information of vertical profile and integrated <span class="hlt">aerosol</span> optical depths at different <span class="hlt">heights</span>. The results showed that the <span class="hlt">aerosol</span> optical depth at 500 nm wavelength during the in-situ measurement campaigns varied from 0.1 to 0.3 in Dunhuang site. And the observation results also indicated that high <span class="hlt">aerosol</span> concentration <span class="hlt">layer</span> mostly located at the <span class="hlt">height</span> of about 2~4 km. These results implies that the <span class="hlt">aerosol</span> concentration of atmosphere in Dunhuang was relatively small and suitable for in-flight calibration for remote sensing satellite sensors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AtmEn..45.6382B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AtmEn..45.6382B"><span id="translatedtitle">Mapping <span class="hlt">aerosol</span> intrusion in Himalayan valleys using the Moderate Resolution Imaging Spectroradiometer (MODIS) and Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brun, Julien; Shrestha, Prabhakar; Barros, Ana P.</p> <p>2011-11-01</p> <p>Mapping the spatial and temporal distribution of <span class="hlt">aerosols</span> along mountain ranges is an important step toward elucidating orographic <span class="hlt">aerosol</span>-cloud-rainfall interactions. This requires high spatial resolution <span class="hlt">aerosol</span> observations over complex topography, which are not currently available either from ground-based observing systems or from remote-sensing products. Here, a novel approach is presented that relies on visible channels from MODIS Rapid Response data at 250 m spatial resolution to extract the daytime <span class="hlt">aerosol</span> run-up (intrusion length and <span class="hlt">height</span>) from the Indo-Gangetic Plains to the High Himalaya. Intrusion length and <span class="hlt">height</span> are determined from the intersection of topography with the MODIS-derived <span class="hlt">aerosol</span> plume using an adaptive object-classification algorithm. The methodology is demonstrated for a case study of the Arun River in eastern Nepal. Results of run-up extraction are examined along with the Total Attenuated Backscatter (Level 1B at 532 nm) from CALIPSO to investigate the regional variability of <span class="hlt">aerosol</span>. During the pre-monsoon season, CALIPSO nighttime profiles show the presence of a slanted dust <span class="hlt">layer</span> following the envelope topography. This is consistent with upper level transport of <span class="hlt">aerosol</span> by north-westerly winds associated with high-frequency dust storms. In the winter, the signal is weaker, and the nighttime elevated <span class="hlt">aerosol</span> <span class="hlt">layer</span> is flat and remains below the envelope orography consistent with blocking conditions. For both seasons, the daytime <span class="hlt">aerosol</span> <span class="hlt">layer</span> detected from MODIS observations is always below the ridges. This suggests that in addition to seasonal variability governed by synoptic conditions, there is a distinct diurnal cycle in the North-South transport of <span class="hlt">aerosol</span> between the Himalayas and the IGP.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AtmEn.125..222S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AtmEn.125..222S"><span id="translatedtitle"><span class="hlt">Aerosol</span> characteristics in the UTLS region: A satellite-based study over north India</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Srivastava, A. K.; Misra, A.; Kanawade, Vijay P.; Devara, P. C. S.</p> <p>2016-01-01</p> <p>Vertical profiles of <span class="hlt">aerosol</span> backscatter coefficient and depolarization ratio, obtained from the Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite, were studied in the upper troposphere and lower stratosphere (UTLS) region over North India (21-30° N and 72-90° E), covering the highly polluted Indo-Gangetic Plain (IGP) for one-year period from December 2011 to November 2012. An enhanced <span class="hlt">aerosol</span> <span class="hlt">layer</span> was observed between 15 and 18 km altitude, in the vicinity of tropopause, with a broad <span class="hlt">layer</span> depth of about 2 km. The <span class="hlt">aerosol</span> <span class="hlt">layer</span> showed strong seasonal, monthly as well as day and night time variability, with a peak value of backscatter coefficient during monsoon season (˜5.54 × 10-3 sr-1 in September). The corresponding depolarization ratio indicates anisotropic (non-spherical) nature of particles. The <span class="hlt">aerosol</span> <span class="hlt">layer</span> was found to be highly linked with the variability in tropopause <span class="hlt">height</span>, showing a positive correlation between tropopause <span class="hlt">height</span> and the <span class="hlt">height</span> of maximum backscatter coefficient (correlation coefficient of 0.8). However, it was found to be negatively correlated with the integrated backscatter coefficient (IBC), with a correlation coefficient of 0.3. We further analyzed outgoing long-wave radiation (OLR) data during the study period to investigate the link between the observed enhanced <span class="hlt">aerosol</span> <span class="hlt">layer</span> in the UTLS region and prevailing deep convective activities over the study region. Low values of OLR during monsoon (about 214 W m-2) indicate the occurrence of deep convection over this region, which may cause a large-scale circulation-driven vertical transport of boundary-<span class="hlt">layer</span> pollution into the atmosphere of UTLS region. Results may have potential implications for better understanding and assessing the chemical and radiative impacts of these <span class="hlt">aerosols</span> in the tropical UTLS region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMGC22A..01W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMGC22A..01W"><span id="translatedtitle">A Process-Modeling Study of <span class="hlt">Aerosol</span>-Cloud-Precipitation Interactions in Response to Controlled Seawater Spray in Marine Boundary <span class="hlt">Layer</span> (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, H.; Rasch, P. J.; Feingold, G.</p> <p>2010-12-01</p> <p>Vast areas of the oceanic surface are covered by stratocumulus (Sc) clouds. They significantly enhance the reflection of incoming solar radiation back to space, leading to a considerable cooling of the Earth-atmosphere system. It has been argued that a 4% increase in the areal coverage or a 0.06 increase in cloud albedo of Sc clouds can offset the warming by atmospheric CO2 doubling (Randall et al. 1984; Latham et al. 2008). Acting as cloud condensation nuclei (CCN), <span class="hlt">aerosol</span> particles can modify cloud albedo, cloud longevity and precipitation efficiency. Recent observational and modeling studies have suggested that <span class="hlt">aerosol</span>, through its effect on precipitation, can alter cloud cellular structures in marine Sc region, representing a powerful modification of clouds by <span class="hlt">aerosol</span>. The possibility of mitigating global warming by spraying sea-salt particles into marine boundary <span class="hlt">layer</span> to brighten Sc clouds was raised by Latham (1990). The idea has been evaluated by several global climate model studies but their inability to represent cloud-scale dynamics and microphysics raises questions about the validity of the results. Using a high-resolution version of the Weather Research and Forecasting (WRF) model, we investigate the impact of seawater spray on the formation and evolution of marine Sc through <span class="hlt">aerosol</span>-cloud-precipitation interactions and dynamical feedback. We will demonstrate how injected <span class="hlt">aerosol</span> particles are transported from the ocean surface into clouds and affect cloud microphysics and macrophysics under various meteorological conditions. We will also use simulation results to explore whether the influx of sea-salt <span class="hlt">aerosols</span> always enhances cloud albedo and how the performance depends on the distribution of sprayers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011287','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011287"><span id="translatedtitle">Estimating the Direct Radiative Effect of Absorbing <span class="hlt">Aerosols</span> Overlying Marine Boundary <span class="hlt">Layer</span> Clouds in the Southeast Atlantic Using MODIS and CALIOP</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Meyer, Kerry; Platnick, Steven; Oreopoulos, Lazaros; Lee, Dongmin</p> <p>2013-01-01</p> <p>Absorbing <span class="hlt">aerosols</span> such as smoke strongly absorb solar radiation, particularly at ultraviolet and visible/near-infrared (VIS/NIR) wavelengths, and their presence above clouds can have considerable implications. It has been previously shown that they have a positive (i.e., warming) direct <span class="hlt">aerosol</span> radiative effect (DARE) when overlying bright clouds. Additionally, they can cause biased passive instrument satellite retrievals in techniques that rely on VIS/NIR wavelengths for inferring the cloud optical thickness (COT) and effective radius (re) of underlying clouds, which can in turn yield biased above-cloud DARE estimates. Here we investigate Moderate Resolution Imaging Spectroradiometer (MODIS) cloud optical property retrieval biases due to overlying absorbing <span class="hlt">aerosols</span> observed by Cloud-<span class="hlt">Aerosol</span> Lidar with Orthogonal Polarization (CALIOP) and examine the impact of these biases on above-cloud DARE estimates. The investigation focuses on a region in the southeast Atlantic Ocean during August and September (2006-2011), where smoke from biomass burning in southern Africa overlies persistent marine boundary <span class="hlt">layer</span> stratocumulus clouds. Adjusting for above-cloud <span class="hlt">aerosol</span> attenuation yields increases in the regional mean liquid COT (averaged over all ocean-only liquid clouds) by roughly 6%; mean re increases by roughly 2.6%, almost exclusively due to the COT adjustment in the non-orthogonal retrieval space. It is found that these two biases lead to an underestimate of DARE. For liquid cloud Aqua MODIS pixels with CALIOP-observed above-cloud smoke, the regional mean above-cloud radiative forcing efficiency (DARE per unit <span class="hlt">aerosol</span> optical depth (AOD)) at time of observation (near local noon for Aqua overpass) increases from 50.9Wm(sup-2)AOD(sup-1) to 65.1Wm(sup-2)AOD(sup -1) when using bias-adjusted instead of nonadjusted MODIS cloud retrievals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A33J3325A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A33J3325A&link_type=ABSTRACT"><span id="translatedtitle">Assessment of 10-Year Global Record of <span class="hlt">Aerosol</span> Products from the OMI Near-UV Algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahn, C.; Torres, O.; Jethva, H. T.</p> <p>2014-12-01</p> <p>Global observations of <span class="hlt">aerosol</span> properties from space are critical for understanding climate change and air quality applications. The Ozone Monitoring Instrument (OMI) onboard the EOS-Aura satellite provides information on <span class="hlt">aerosol</span> optical properties by making use of the large sensitivity to <span class="hlt">aerosol</span> absorption and dark surface albedo in the UV spectral region. These unique features enable us to retrieve both <span class="hlt">aerosol</span> extinction optical depth (AOD) and single scattering albedo (SSA) successfully from radiance measurements at 354 and 388 nm by the OMI near UV <span class="hlt">aerosol</span> algorithm (OMAERUV). Recent improvements to algorithms in conjunction with the Cloud-<span class="hlt">Aerosol</span> Lidar with Orthogonal Polarization (CALIOP) and Atmospheric Infrared Sounder (AIRS) carbon monoxide data also reduce uncertainties due to <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">heights</span> and types significantly in retrieved products. We present validation results of OMI AOD against space and time collocated <span class="hlt">Aerosol</span> Robotic Network (AERONET) measured AOD values over multiple stations representing major <span class="hlt">aerosol</span> episodes and regimes. We also compare the OMI SSA against the inversion made by AERONET as well as an independent network of ground-based radiometer called SKYNET in Japan, China, South-East Asia, India, and Europe. The outcome of the evaluation analysis indicates that in spite of the "row anomaly" problem, affecting the sensor since mid-2007, the long-term <span class="hlt">aerosol</span> record shows remarkable sensor stability. The OMAERUV 10-year global <span class="hlt">aerosol</span> record is publicly available at the NASA data service center web site (http://disc.sci.gsfc.nasa.gov/Aura/data-holdings/OMI/omaeruv_v003.shtml).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080044769&hterms=aerosols+desert&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Daerosols%2Bdesert','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080044769&hterms=aerosols+desert&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Daerosols%2Bdesert"><span id="translatedtitle"><span class="hlt">Aerosol</span> Source Plume Physical Characteristics from Space-based Multiangle Imaging</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kahn, Ralph A.; Li, W.-H.; Moroney, Catherine; Diner, David J.; Martonchik, John V.; Fishbein, Evan</p> <p>2007-01-01</p> <p>Models that assess <span class="hlt">aerosol</span> effects on regional air quality and global climate parameterize <span class="hlt">aerosol</span> sources in terms of amount, type, and injection <span class="hlt">height</span>. The multiangle imaging spectroradiometer (MISR) aboard NASA's Terra satellite retrieves total column <span class="hlt">aerosol</span> optical thickness (AOT), and <span class="hlt">aerosol</span> type over cloud-free land and water. A stereo-matching algorithm automatically retrieves reflecting-<span class="hlt">layer</span> altitude wherever clouds or <span class="hlt">aerosol</span> plumes have discernable spatial contrast, with about 500-m accuracy, at 1.1-km horizontal resolution. Near-source biomass burning smoke, volcanic effluent, and desert dust plumes are observed routinely, providing information about <span class="hlt">aerosol</span> amount, particle type, and injection <span class="hlt">height</span> useful for modeling applications. Compared to background <span class="hlt">aerosols</span>, the plumes sampled have higher AOT, contain particles having expected differences in Angstrom exponent, size, single-scattering albedo, and for volcanic plume and dust cloud cases, particle shape. As basic thermodynamics predicts, thin <span class="hlt">aerosol</span> plumes lifted only by regional winds or less intense heat sources are confined to the boundary <span class="hlt">layer</span>. However, when sources have sufficient buoyancy, the representative plumes studied tend to concentrate within discrete, high-elevation <span class="hlt">layers</span> of local stability; the <span class="hlt">aerosol</span> is not uniformly distributed up to a peak altitude, as is sometimes assumed in modeling. MISR-derived plume <span class="hlt">heights</span>, along with meteorological profile data from other sources, make it possible to relate radiant energy flux observed by the moderate resolution imaging spectroradiometer (MODIS), also aboard the Terra spacecraft, to convective heat flux that plays a major role in buoyant plume dynamics. A MISR climatology of plume behavior based on these results is being developed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26421659','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26421659"><span id="translatedtitle">Estimation of surface-level PM concentration from satellite observation taking into account the <span class="hlt">aerosol</span> vertical profiles and hygroscopicity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Kwanchul; Lee, Kwon H; Kim, Ji I; Noh, Youngmin; Shin, Dong H; Shin, Sung K; Lee, Dasom; Kim, Jhoon; Kim, Young J; Song, Chul H</p> <p>2016-01-01</p> <p>Surface-level PM10 distribution was estimated from the satellite <span class="hlt">aerosol</span> optical depth (AOD) products, taking the account of vertical profiles and hygroscopicity of <span class="hlt">aerosols</span> over Jeju, Korea during March 2008 and October 2009. In this study, MODIS AOD data from the Terra and Aqua satellites were corrected with <span class="hlt">aerosol</span> extinction profiles and relative humidity data. PBLH (Planetary Boundary <span class="hlt">Layer</span> <span class="hlt">Height</span>) was determined from MPLNET lidar-derived <span class="hlt">aerosol</span> extinction coefficient profiles. Through statistical analysis, better agreement in correlation (R = 0.82) between the hourly PM10 concentration and hourly average Sunphotometer AOD was the obtained when vertical fraction method (VFM) considering Haze <span class="hlt">Layer</span> <span class="hlt">Height</span> (HLH) and hygroscopic growth factor f(RH) was used. The validity of the derived relationship between satellite AOD and surface PM10 concentration clearly demonstrates that satellite AOD data can be utilized for remote sensing of spatial distribution of regional PM10 concentration. PMID:26421659</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012cosp...39...80B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39...80B"><span id="translatedtitle">High altitude balloon measurements of free tropospheric black carbon: Do BC <span class="hlt">aerosol</span> <span class="hlt">layers</span> build "their own homes" up in the atmosphere?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Babu, S. Suresh; Manchanda, R. K.; Shankarnarayan, Sreenivasan; Sinha, P. R.; Krishna Moorthy, K.; Prasad Vajja, Dinakar; Arunkumar, V. H.; Satheesh, S. K.</p> <p>2012-07-01</p> <p>First ever high altitude balloon measurements of the vertical profiles of the mass concentration of <span class="hlt">aerosol</span> black carbon (BC) concurrently with the atmospheric thermodynamical parameters were made in the troposphere ( up to 9 km) from the National Balloon Facility at Hyderabad as a part of the Regional <span class="hlt">Aerosol</span> warming Experiment (RAWEX) of ARFI Project (ISRO-GBP) during March 2010. The altitude distribution of BC showed multiple peaks, at ˜ 4.5 km and above 8 km. Associated with these, rapid decrease in the environmental lapse rate and a sharp increase in the atmospheric stability were observed, probably caused by the atmospheric warming by the BC <span class="hlt">layers</span>. Estimation of the heating rate profile using the altitude distribution of BC and the vertical profile of extinction coefficient from the CALIPSO, which had an over pass over the region on the day of BC profiling, revealed very large heating (˜ 2.8 K day-1) at ˜ 4.5 km. This experiment provided the first experimental evidence and quantification of the effects of BC absorption on the stability of the atmosphere. The elevated BC <span class="hlt">layers</span> in the free troposphere absorb solar radiation leading to warming of the local ambient, which increases the atmospheric stability. The stable <span class="hlt">layer</span>, thus created, is conducive for maintaining the BC <span class="hlt">layer</span> longer, without dissipation (by inhibiting turbulent mixing) and thus increases its lifetime leading to further enhanced absorption. Thus raises an interesting question: Do BC <span class="hlt">layers</span> build `their own homes' up in the atmosphere?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/263556','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/263556"><span id="translatedtitle">Cirrus and <span class="hlt">aerosol</span> lidar profilometer - analysis and results</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Spinhirne, J.D.; Scott, V.S.; Reagan, J.A.; Galbraith, A.</p> <p>1996-04-01</p> <p>A cloud and <span class="hlt">aerosol</span> lidar set from over a year of near continuous operation of a micro pulse lidar (MPL) instrument at the Cloud and Radiation Testbed (CART) site has been established. MPL instruments are to be included in the Ames Research Center (ARC) instrument compliments for the SW Pacific and Arctic ARM sites. Operational processing algorithms are in development for the data sets. The derived products are to be cloud presence and classification, base <span class="hlt">height</span>, cirrus thickness, cirrus optical thickness, cirrus extinction profile, <span class="hlt">aerosol</span> optical thickness and profile, and planetary boundary <span class="hlt">layer</span> (PBL) <span class="hlt">height</span>. A cloud presence and base <span class="hlt">height</span> algorithm is in use, and a data set from the CART site is available. The scientific basis for the algorithm development of the higher level data products and plans for implementation are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AIPC.1734o0004E&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AIPC.1734o0004E&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Aerosols</span> attenuating the solar radiation collected by solar tower plants: The horizontal pathway at surface level</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elias, Thierry; Ramon, Didier; Dubus, Laurent; Bourdil, Charles; Cuevas-Agulló, Emilio; Zaidouni, Taoufik; Formenti, Paola</p> <p>2016-05-01</p> <p><span class="hlt">Aerosols</span> attenuate the solar radiation collected by solar tower plants (STP), along two pathways: 1) the atmospheric column pathway, between the top of the atmosphere and the heliostats, resulting in Direct Normal Irradiance (DNI) changes; 2) the grazing pathway close to surface level, between the heliostats and the optical receiver. The attenuation along the surface-level grazing pathway has been less studied than the <span class="hlt">aerosol</span> impact on changes of DNI, while it becomes significant in STP of 100 MW or more. Indeed <span class="hlt">aerosols</span> mostly lay within the surface atmospheric <span class="hlt">layer</span>, called the boundary <span class="hlt">layer</span>, and the attenuation increases with the distance covered by the solar radiation in the boundary <span class="hlt">layer</span>. In STP of 100 MW or more, the distance between the heliostats and the optical receiver becomes large enough to produce a significant attenuation by <span class="hlt">aerosols</span>. We used measured <span class="hlt">aerosol</span> optical thickness and computed boundary <span class="hlt">layer</span> <span class="hlt">height</span> to estimate the attenuation of the solar radiation at surface level at Ouarzazate (Morocco). High variabilities in <span class="hlt">aerosol</span> amount and in vertical <span class="hlt">layering</span> generated a significant magnitude in the annual cycle and significant inter-annual changes. Indeed the annual mean of the attenuation caused by <span class="hlt">aerosols</span> over a 1-km heliostat-receiver distance was 3.7% in 2013, and 5.4% in 2014 because of a longest desert dust season. The monthly minimum attenuation of less than 3% was observed in winter and the maximum of more than 7% was observed in summer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JAtS...62.2037G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JAtS...62.2037G"><span id="translatedtitle">Freezing Drizzle Formation in Stably Stratified <span class="hlt">Layer</span> Clouds. Part II: The Role of Giant Nuclei and <span class="hlt">Aerosol</span> Particle Size Distribution and Solubility.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geresdi, István; Rasmussen, Roy</p> <p>2005-07-01</p> <p>This paper investigates how the characteristics of <span class="hlt">aerosol</span> particles (size distribution and solubility) as well as the presence of giant nuclei affect drizzle formation in stably stratified <span class="hlt">layer</span> clouds. A new technique was developed to simulate the evolution of water drops from wet <span class="hlt">aerosol</span> particles and implemented into a detailed microphysical model. The detailed microphysical model was incorporated into a one-dimensional parcel model and a two-dimensional version of the fifth-generation Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) Mesoscale Model (MM5). Sensitivity experiments were performed with the parcel model using a constant updraft speed and with the two-dimensional model by simulating flow over a bell-shaped mountain. The results showed that 1) stably stratified clouds with weak updrafts (<10 cms-1) can form drizzle relatively rapidly for maritime size distributions with any <span class="hlt">aerosol</span> particle solubility, and for continental size distributions with highly insoluble particles due to the low number of activated cloud condensation nuclei (CCN) (<100 cm-3), 2) drizzle is suppressed in stably stratified clouds with weak updrafts (<10 cms-1) for highly soluble urban and extreme urban size distributions, and 3) the presence of giant nuclei only has an effect on drizzle formation for the highly soluble continental <span class="hlt">aerosol</span> size distributions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/924666','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/924666"><span id="translatedtitle">Multi-Sensor Estimation of Mixing <span class="hlt">Heights</span> Over a Coastal City</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nielsen-Gammon, John W.; Powell, Christina L.; Mahoney, Michael J.; Angevine, Wayne M.; Senff, Christoph; White, Allen B.; Berkowitz, Carl M.; Doran, J. C.; Knupp, Kevin</p> <p>2008-01-01</p> <p>An airborne Microwave Temperature Profiler (MTP) was deployed during the An airborne Microwave Temperature Profiler (MTP) was deployed during the Texas 2000 Air Quality Study (TexAQS-2000) to make measurements of boundary <span class="hlt">layer</span> thermal structure. An objective technique is developed and tested for estimating the mixed <span class="hlt">layer</span> (ML) <span class="hlt">height</span> from the MTP vertical temperature profiles. The technique identifies the ML <span class="hlt">height</span> as a threshold increase of potential temperature from its minimum value within the boundary <span class="hlt">layer</span>. In order to calibrate the technique and evaluate the usefulness of this approach, coincident estimates from radiosondes, radar wind profilers, an <span class="hlt">aerosol</span> backscatter lidar, and in situ aircraft measurements were compared with each other and with the MTP. Relative biases among all instruments were generally less than 50 m, and the agreement between MTP ML <span class="hlt">height</span> estimates and other estimates was at least as good as the agreement among the other estimates. The ML <span class="hlt">height</span> estimates from the MTP and other instruments are utilized to determine the spatial and temporal evolution of ML <span class="hlt">height</span> in the Houston area on 1 Sept. 2000. An elevated temperature inversion was present, so ML growth was inhibited until early afternoon. In the afternoon, large spatial variations in ML <span class="hlt">height</span> developed across the Houston area. The highest ML <span class="hlt">heights</span>, well over 2 km, were observed to the north of Houston, while downwind of Galveston Bay and within the late afternoon sea breeze ML <span class="hlt">heights</span> were much lower. The spatial variations that were found away from the immediate influence of coastal circulations were unexpected, and multiple independent ML <span class="hlt">height</span> estimates were essential for documenting this feature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://eosweb.larc.nasa.gov/project/cats/cats-iss_l2o_d-m7-2-v1-03_05kmpro','SCIGOV-ASDC'); return false;" href="https://eosweb.larc.nasa.gov/project/cats/cats-iss_l2o_d-m7-2-v1-03_05kmpro"><span id="translatedtitle">CATS-ISS_L2O_D-M7.2-V1-03_05kmPro</span></a></p> <p><a target="_blank" href="http://eosweb.larc.nasa.gov/">Atmospheric Science Data Center </a></p> <p></p> <p>2016-04-27</p> <p>... Cloud Backscatter Cloud <span class="hlt">Layer</span> Thickness Cloud <span class="hlt">Layer</span> <span class="hlt">Height</span> Cloud Ice Water Content Cloud Depolarization Cloud Phase <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> <span class="hlt">Height</span> <span class="hlt">Aerosol</span> <span class="hlt">Layer</span> Thickness <span class="hlt">Aerosol</span> Backscatter <span class="hlt">Aerosol</span> Optical ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002PhDT........55D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002PhDT........55D"><span id="translatedtitle">Characterization of marine boundary <span class="hlt">layer</span> <span class="hlt">aerosol</span> from North Atlantic and European sources: Physical and chemical properties and climate forcing parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dusek, Ulrike</p> <p></p> <p>This thesis focuses on <span class="hlt">aerosol</span> properties measured in Southwestern Portugal during the second <span class="hlt">Aerosol</span> Characterization Experiment. Fundamental <span class="hlt">aerosol</span> physical properties such as particle size distribution and hygroscopic properties are related to possible sources and <span class="hlt">aerosol</span> transformation processes. From these fundamental properties we derive <span class="hlt">aerosol</span> properties that are important for <span class="hlt">aerosol</span> forcing of climate. First, a new method for calculating CCN spectra is proposed in this work and tested using sensitivity studies and comparisons to direct measurements. The measured and calculated CCN spectra differ on average by 30%, which at small supersaturations is similar to the measurement uncertainties. Second, <span class="hlt">aerosol</span> number to volume ratios (R) are calculated and the fact that values of R are relatively constrained is explained based on observed correlations between size distribution parameters. Third, a simple parameterization of the humidity dependence of the submicron <span class="hlt">aerosol</span> scattering coefficient has been derived, depending only on a volume weighted average diameter growth factor and the volume mean diameter of the dry size distribution. One set of empirical parameters can be used to parameterize all <span class="hlt">aerosol</span> types characterized during the ACE-2 measurement period. <span class="hlt">Aerosol</span> physical properties and climate forcing parameters in the North-East Atlantic Ocean were clearly affected by pollution outbreaks from Europe. The submicron particle volume increased by a factor of 5 in polluted conditions, the light scattering coefficient of dry particles increased on average by a factor of up to 10, CCN concentrations at supersaturations of 0.2% increased by a factor of 3--5. The <span class="hlt">aerosol</span> fundamental properties vary often strongly with air mass history, but also show short-term variability that often has a characteristic diurnal scale. The number concentration of fine particles below 50nm and the particle hygroscopic growth factors are mostly dominated by diurnal processes</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010069577','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010069577"><span id="translatedtitle">Measurements of <span class="hlt">Aerosol</span> Vertical Profiles and Optical Properties during INDOEX 1999 Using Micro-Pulse Lidars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Welton, Ellsworth J.; Voss, Kenneth J.; Quinn, Patricia K.; Flatau, Piotr J.; Markowicz, Krzysztof; Campbell, James R.; Spinhirne, James D.; Gordon, Howard R.; Johnson, James E.; Starr, David OC. (Technical Monitor)</p> <p>2001-01-01</p> <p>Micro-pulse lidar systems (MPL) were used to measure <span class="hlt">aerosol</span> properties during the Indian Ocean Experiment (INDOEX) 1999 field phase. Measurements were made from two platforms: the NOAA ship RN Ronald H. Brown, and the Kaashidhoo Climate Observatory (KCO) in the Maldives. Sunphotometers were used to provide <span class="hlt">aerosol</span> optical depths (AOD) needed to calibrate the MPL. This study focuses on the <span class="hlt">height</span> distribution and optical properties (at 523 nm) of <span class="hlt">aerosols</span> observed during the campaign. The <span class="hlt">height</span> of the highest <span class="hlt">aerosols</span> (top <span class="hlt">height</span>) was calculated and found to be below 4 km for most of the cruise. The marine boundary <span class="hlt">layer</span> (MBL) top was calculated and found to be less than 1 km. MPL results were combined with air mass trajectories, radiosonde profiles of temperature and humidity, and <span class="hlt">aerosol</span> concentration and optical measurements. Humidity varied from approximately 80% near the surface to 50% near the top <span class="hlt">height</span> during the entire cruise. The average value and standard deviation of <span class="hlt">aerosol</span> optical parameters were determined for characteristic air mass regimes. Marine <span class="hlt">aerosols</span> in the absence of any continental influence were found to have an AOD of 0.05 +/- 0.03, an extinction-to-backscatter ratio (S-ratio) of 33 +/- 6 sr, and peak extinction values around 0.05/km (near the MBL top). The marine results are shown to be in agreement with previously measured and expected values. Polluted marine areas over the Indian Ocean, influenced by continental <span class="hlt">aerosols</span>, had AOD values in excess of 0.2, S-ratios well above 40 sr, and peak extinction values approximately 0.20/km (near the MBL top). The polluted marine results are shown to be similar to previously published values for continental <span class="hlt">aerosols</span>. Comparisons between MPL derived extinction near the ship (75 m) and extinction calculated at ship-level using scattering measured by a nephelometer and absorption using a PSAP were conducted. The comparisons indicated that the MPL algorithm (using a constant S-ratio throughout the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A43A0262J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.A43A0262J&link_type=ABSTRACT"><span id="translatedtitle">Characterization of smoke <span class="hlt">aerosols</span> over the Indochina Peninsula from multi-platform satellite observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jeong, M. J.; Hsu, N. Y. C.; Lee, J.; Sayer, A. M.; Bettenhausen, C.; Huang, J.</p> <p>2015-12-01</p> <p>Multi-faceted near-simultaneous observations from the sensors aboard multiple satellite platforms, so called the A-Train, are utilized to characterize the spatial distributions and the optical properties of smoke <span class="hlt">aerosols</span> over the Indochina Peninsula. Observations from the A-Train sensors, especially, MODerate resolution Imaging Spectroradiometer (MODIS), Ozone Monitoring Instrument (OMI), and Cloud-<span class="hlt">Aerosol</span> Lidar with Orthogonal Polarization (CALIOP), are synthesized to retrieve single-scattering albedo (SSA) and effective <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span> (ALH) of BBS <span class="hlt">aerosols</span> in the region. The retrieval algorithm extracts the absorption and <span class="hlt">height</span> information about smoke <span class="hlt">aerosols</span>, which is lumped into ultraviolet spectra at the top of the atmosphere, by taking the most reliable information contents that each satellite measurement can deliver. The results of retrieved SSA and ALH showed reasonable agreements with in-situ measurements, <span class="hlt">AEROsol</span> Robotic NETwork (AERONET) data, and lidar-based observations. The uncertainty and sensitivity of the retrieval algorithm are also presented. The retrieved quantities are then used together with other satellite datasets to characterize the three-dimensional distributions of smoke <span class="hlt">aerosols</span> over the Indochina Peninsular during the boreal spring time. Given the frequent horizontal collocations of smoke and clouds in the region, implication of smoke vertical distributions for long-range transports is also discussed. The results of this study are anticipated to advance our understanding on the climatic impacts of the smoke <span class="hlt">aerosols</span> in the region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19151820','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19151820"><span id="translatedtitle">Scanning tropospheric ozone and <span class="hlt">aerosol</span> lidar with double-gated photomultipliers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Machol, Janet L; Marchbanks, Richard D; Senff, Christoph J; McCarty, Brandi J; Eberhard, Wynn L; Brewer, William A; Richter, Ronald A; Alvarez, Raul J; Law, Daniel C; Weickmann, Ann M; Sandberg, Scott P</p> <p>2009-01-20</p> <p>The Ozone Profiling Atmospheric Lidar is a scanning four-wavelength ultraviolet differential absorption lidar that measures tropospheric ozone and <span class="hlt">aerosols</span>. Derived profiles from the lidar data include ozone concentration, <span class="hlt">aerosol</span> extinction, and calibrated <span class="hlt">aerosol</span> backscatter. <span class="hlt">Aerosol</span> calibrations assume a clear air region aloft. Other products include cloud base <span class="hlt">heights</span>, <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">heights</span>, and scans of particulate plumes from aircraft. The <span class="hlt">aerosol</span> data range from 280 m to 12 km with 5 m range resolution, while the ozone data ranges from 280 m to about 1.2 km with 100 m resolution. In horizontally homogeneous atmospheres, data from multiple-elevation angles is combined to reduce the minimum altitude of the <span class="hlt">aerosol</span> and ozone profiles to about 20 m. The lidar design, the characterization of the photomultiplier tubes, ozone and <span class="hlt">aerosol</span> analysis techniques, and sample data are described. Also discussed is a double-gating technique to shorten the gated turn-on time of the photomultiplier tubes, and thereby reduce the detection of background light and the outgoing laser pulse. PMID:19151820</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990028511&hterms=Structure+Properties&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DStructure%2BProperties','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990028511&hterms=Structure+Properties&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DStructure%2BProperties"><span id="translatedtitle">A Multi-Instrument Approach for Characterizing the Vertical Structure of <span class="hlt">Aerosol</span> Properties: Case Studies in the Pacific Basin Troposphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Redemann, J.; Turco, R. P.; Pueschel, R. F.; Fenn, M. A.; Browell, E. V.; Grant, W. B.</p> <p>1998-01-01</p> <p>During February/March 1994, a series of aircraft-based <span class="hlt">aerosol</span> measurements were carried out in the Pacific Basin troposphere using a differential absorption lidar system deployed by NASA Langley, and optical spectrometer probes and a wire-impactor system operated by NASA Ames. A modified Klett inversion algorithm was applied to extract altitude profiles of <span class="hlt">aerosol</span> backscattering from the IR lidar signal. The algorithm that we have designed for this purpose utilizes the in situ <span class="hlt">aerosol</span> measurements to normalize the lidar profile at the aircraft altitude and to supply the lidar ratio as a function of <span class="hlt">height</span>. The lidar-derived <span class="hlt">aerosol</span> backscattering coefficients were then compared to the backscattering coefficients calculated from the in situ measurements. During several local aircraft descents, we found good agreement between the remote lidar and in situ results for the absolute value of the <span class="hlt">aerosol</span> backscattering coefficient and its altitude variation only when we allowed for several <span class="hlt">layers</span> with different <span class="hlt">aerosol</span> refractive indices. The agreement validates our lidar calibration method and provides an indication of the variation in <span class="hlt">aerosol</span> refractive index as a function of altitude. Two of the three case studies performed in this paper reveal <span class="hlt">layers</span> of anthropogenic <span class="hlt">aerosols</span> transported long distances into the Pacific Basin troposphere. A third case implies the existence of a <span class="hlt">layer</span> of dustlike <span class="hlt">aerosol</span> particles in the lower troposphere, most likely of Asian origin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..1510267B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..1510267B&link_type=ABSTRACT"><span id="translatedtitle">Intercomparison of <span class="hlt">aerosol</span> optical parameters from WALI and R-MAN510 <span class="hlt">aerosol</span> Raman lidars in the framework of HyMeX campaign</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boytard, Mai-Lan; Royer, Philippe; Chazette, Patrick; Shang, Xiaoxia; Marnas, Fabien; Totems, Julien; Bizard, Anthony; Bennai, Baya; Sauvage, Laurent</p> <p>2013-04-01</p> <p>The HyMeX program (Hydrological cycle in Mediterranean eXperiment) aims at improving our understanding of hydrological cycle in the Mediterranen and at a better quantification and forecast of high-impact weather events in numerical weather prediction models. The first Special Observation Period (SOP1) took place in September/October 2012. During this period two <span class="hlt">aerosol</span> Raman lidars have been deployed at Menorca Island (Spain) : one Water-vapor and <span class="hlt">Aerosol</span> Raman LIdar (WALI) operated by LSCE/CEA (Laboratoire des Sciences du Climat et de l'Environnement/Commissariat à l'Energie Atomique) and one <span class="hlt">aerosol</span> Raman and dual-polarization lidar (R-Man510) developed and commercialized by LEOSPHERE company. Both lidars have been continuously running during the campaign and have provided information on <span class="hlt">aerosol</span> and cloud optical properties under various atmospheric conditions (maritime background <span class="hlt">aerosols</span>, dust events, cirrus clouds...). We will present here the results of intercomparisons between R-Man510, and WALI <span class="hlt">aerosol</span> lidar systems and collocated sunphotometer measurements. Limitations and uncertainties on the retrieval of extinction coefficients, depolarization ratio, <span class="hlt">aerosol</span> optical depths and detection of atmospheric structures (planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span>, <span class="hlt">aerosol</span>/cloud <span class="hlt">layers</span>) will be discussed according atmospheric conditions. The results will also be compared with theoretical uncertainty assessed with direct/inverse model of lidar profiles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JQSRT.153..102L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JQSRT.153..102L"><span id="translatedtitle">Comparisons of PBL <span class="hlt">heights</span> derived from CALIPSO and ECMWF reanalysis data over China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Jingjing; Huang, Jianping; Chen, Bin; Zhou, Tian; Yan, Hongru; Jin, Hongchun; Huang, Zhongwei; Zhang, Beidou</p> <p>2015-03-01</p> <p>Planetary boundary <span class="hlt">layer</span> (PBL) <span class="hlt">height</span> was estimated using the maximum standard deviation method for Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) attenuated backscatter observations. It was only retrieved under conditions where the clouds accounted for less than 5% in a profile, where it could be compared with ground lidar results at SACOL. The correlation between CALIPSO and the ground lidar was 0.73. We present the seasonal mean patterns of 4-year mid-day PBL <span class="hlt">heights</span> over China and use them to evaluate the European Centre for Medium-Range Weather Forecasts (ECMWF) PBL depth retrievals, inform boundary <span class="hlt">layer</span> studies, and improve our understanding of how PBL <span class="hlt">height</span> mediates exchanges of energy and pollutants between the surface and the atmosphere. We found that the largest PBL <span class="hlt">heights</span> occurred over the Tibetan Plateau and coastal areas. The smallest PBL <span class="hlt">heights</span> appeared in the Tarim Basin and northeast of China during local winter. A comparison of CALIPSO and ECMWF PBL under different land-cover conditions showed that the PBL depth estimated by the CALIPSO backscatter climatology is larger over ocean and forest surface than that estimated from ECMWF data. However, the PBL <span class="hlt">heights</span> of ECMWF that were larger than those of CALIPSO were mainly concentrated over grassland and bare land surface in spring and summer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950004641','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950004641"><span id="translatedtitle">Stratospheric <span class="hlt">aerosol</span> increase after eruption of Pinatubo observed with lidar and aureolemeter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hayashida, Sachiko; Sasano, Yasuhiro; Nakane, Hideaki; Matsui, Ichiro; Hayasaka, Tadahiro</p> <p>1994-01-01</p> <p>An increase in the amount of stratospheric <span class="hlt">aerosol</span> due to the Pinatubo eruption (June 12-15, 1991, 15.14 deg N, 120.35 deg E) was observed from the end of June, 1991 by a lidar in NIES (National Institute for Environmental Studies), Tsukuba (36.0 deg N, 140.1 deg E). After large fluctuations in summer of 1991, the amount of the <span class="hlt">aerosols</span> increased in mid-September as a result of enhanced transportation from the subtropical region. In autumn and winter of 1991, dense <span class="hlt">aerosol</span> <span class="hlt">layers</span> were continuously observed. Aureolemeter (scanning spectral radiometer) measurements were also carried out with lidar measurements and columnar size distribution of stratospheric <span class="hlt">aerosols</span> was estimated for some cases. Collaborative measurements with the lidar and aureolemeter provided some information on <span class="hlt">height</span> distribution of the surface area of <span class="hlt">aerosols</span> in late 1991.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980201315','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980201315"><span id="translatedtitle">Radiative Effects of <span class="hlt">Aerosols</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Valero, Francisco P. J.</p> <p>1997-01-01</p> <p>During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in <span class="hlt">aerosol</span> optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size resolved <span class="hlt">aerosol</span> microphysics and chemistry. Both profiles included pollution haze <span class="hlt">layer</span> from Europe but the second also included the effect of a Saharan dust <span class="hlt">layer</span> above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) <span class="hlt">aerosol</span> were determined and thermal analysis of the pollution haze indicated that the fine <span class="hlt">aerosol</span> was composed primarily of a sulfate/water mixture with a refractory soot-like core.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.4254P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.4254P&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Aerosol</span> Climate Time Series in ESA <span class="hlt">Aerosol</span>_cci</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Popp, Thomas; de Leeuw, Gerrit; Pinnock, Simon</p> <p>2016-04-01</p> <p>Within the ESA Climate Change Initiative (CCI) <span class="hlt">Aerosol</span>_cci (2010 - 2017) conducts intensive work to improve algorithms for the retrieval of <span class="hlt">aerosol</span> information from European sensors. Meanwhile, full mission time series of 2 GCOS-required <span class="hlt">aerosol</span> parameters are completely validated and released: <span class="hlt">Aerosol</span> Optical Depth (AOD) from dual view ATSR-2 / AATSR radiometers (3 algorithms, 1995 - 2012), and stratospheric extinction profiles from star occultation GOMOS spectrometer (2002 - 2012). Additionally, a 35-year multi-sensor time series of the qualitative Absorbing <span class="hlt">Aerosol</span> Index (AAI) together with sensitivity information and an AAI model simulator is available. Complementary <span class="hlt">aerosol</span> properties requested by GCOS are in a "round robin" phase, where various algorithms are inter-compared: fine mode AOD, mineral dust AOD (from the thermal IASI spectrometer, but also from ATSR instruments and the POLDER sensor), absorption information and <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span>. As a quasi-reference for validation in few selected regions with sparse ground-based observations the multi-pixel GRASP algorithm for the POLDER instrument is used. Validation of first dataset versions (vs. AERONET, MAN) and inter-comparison to other satellite datasets (MODIS, MISR, SeaWIFS) proved the high quality of the available datasets comparable to other satellite retrievals and revealed needs for algorithm improvement (for example for higher AOD values) which were taken into account for a reprocessing. The datasets contain pixel level uncertainty estimates which were also validated and improved in the reprocessing. For the three ATSR algorithms the use of an ensemble method was tested. The paper will summarize and discuss the status of dataset reprocessing and validation. The focus will be on the ATSR, GOMOS and IASI datasets. Pixel level uncertainties validation will be summarized and discussed including unknown components and their potential usefulness and limitations. Opportunities for time series extension</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006SPIE.6411E..1PK','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006SPIE.6411E..1PK"><span id="translatedtitle">For assessing yields under extreme climatic events using crop simulation models: <span class="hlt">aerosol</span> <span class="hlt">layer</span> effects on growth and yield of wheat, rice, and sugarcane</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalra, Naveen; Chakraborty, D.; Sahoo, R. N.; Sehgal, V. K.; Singh, Manish</p> <p>2006-12-01</p> <p><span class="hlt">Aerosol</span> presence reduces sunshine hours and the amount of radiation received. The extent of reduction in radiation during this extreme event (January-March 1999) was relatively lower, as the extent of the diffused radiation increases. During this time, the reduction ranged from 5-12%. The differential response of the crops (wheat, rice and sugarcane) under changed proportion of direct and diffused radiation due to haze was seen through using crop simulation models (WTGROWS for wheat, DSSAT for rice and sugarcane). The growing conditions were optimal. Regions chosen for simulation were north-west India for wheat, coastal and southern regions for rice and north-eastern, western and southern regions for sugarcane. Simulation results were obtained in terms of phenology, biomass and economic yield at harvest. There was slight reduction in the yield of these three crops due to reduction in the radiation, but coupled weather changes (lowering of temperature, etc.) due to cloudy condition could benefit the crops through phenology modifications and other crop process activities, which can some times give higher yields of crops under the <span class="hlt">aerosol</span> <span class="hlt">layer</span> when compared to no haze <span class="hlt">layer</span> situation. Diffused radiation is more photo-synthetically active, and this feature has still to be included in most of the existing crop growth models, as the existing crop models do not differentiate between direct and diffused radiation. The scope of using remote sensing for assessing the haze <span class="hlt">layer</span> (spatial and temporal extent) could be employed in the crop simulation models for regional impact analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A52A..05R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A52A..05R&link_type=ABSTRACT"><span id="translatedtitle">Use of the NASA GEOS-5 SEAC4RS Meteorological and <span class="hlt">Aerosol</span> Reanalysis for assessing simulated <span class="hlt">aerosol</span> optical properties as a function of smoke age</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Randles, C. A.; da Silva, A. M., Jr.; Colarco, P. R.; Darmenov, A.; Buchard, V.; Govindaraju, R.; Chen, G.; Hair, J. W.; Russell, P. B.; Shinozuka, Y.; Wagner, N.; Lack, D.</p> <p>2014-12-01</p> <p>The NASA Goddard Earth Observing System version 5 (GEOS-5) Earth system model, which includes an online <span class="hlt">aerosol</span> module, provided chemical and weather forecasts during the SEAC4RS field campaign. For post-mission analysis, we have produced a high resolution (25 km) meteorological and <span class="hlt">aerosol</span> reanalysis for the entire campaign period. In addition to the full meteorological observing system used for routine NWP, we assimilate 550 nm <span class="hlt">aerosol</span> optical depth (AOD) derived from MODIS (both Aqua and Terra satellites), ground-based AERONET sun photometers, and the MISR instrument (over bright surfaces only). Daily biomass burning emissions of CO, CO2, SO2, and <span class="hlt">aerosols</span> are derived from MODIS fire radiative power retrievals. We have also introduced novel smoke "age" tracers, which provide, for a given time, a snapshot histogram of the age of simulated smoke <span class="hlt">aerosol</span>. Because GEOS-5 assimilates remotely sensed AOD data, it generally reproduces observed (column) AOD compared to, for example, the airborne 4-STAR instrument. Constraining AOD, however, does not imply a good representation of either the vertical profile or the <span class="hlt">aerosol</span> microphysical properties (e.g., composition, absorption). We do find a reasonable vertical structure for <span class="hlt">aerosols</span> is attained in the model, provided actual smoke injection <span class="hlt">heights</span> are not much above the planetary boundary <span class="hlt">layer</span>, as verified with observations from DIAL/HRSL aboard the DC8. The translation of the simulated <span class="hlt">aerosol</span> microphysical properties to total column AOD, needed in the <span class="hlt">aerosol</span> assimilation step, is based on prescribed mass extinction efficiencies that depend on wavelength, composition, and relative humidity. Here we also evaluate the performance of the simulated <span class="hlt">aerosol</span> speciation by examining in situ retrievals of <span class="hlt">aerosol</span> absorption/single scattering albedo and scattering growth factor (f(RH)) from the LARGE and AOP suite of instruments. Putting these comparisons in the context of smoke age as diagnosed by the model helps us to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ACPD...15.9507L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ACPD...15.9507L&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Aerosol</span> vertical distribution, optical properties and transport over Corsica (western Mediterranean)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Léon, J.-F.; Augustin, P.; Mallet, M.; Bourrianne, T.; Pont, V.; Dulac, F.; Fourmentin, M.; Lambert, D.; Sauvage, B.</p> <p>2015-03-01</p> <p>This paper presents the <span class="hlt">aerosol</span> vertical distribution observed in the western Mediterranean between February and April 2011 and between February 2012 and August 2013. An elastic backscattering lidar was continuously operated at a coastal site in the northern part of Corsica Island (Cap Corse) for a total of more than 14 000 h of observations. The <span class="hlt">aerosol</span> extinction coefficient retrieved from cloud-free lidar profiles are analyzed along with the SEVIRI satellite <span class="hlt">aerosol</span> optical depth (AOD). The SEVIRI AOD was used to constrain the retrieval of the <span class="hlt">aerosol</span> extinction profiles from the lidar range-corrected signal and to detect the presence of dust or pollution <span class="hlt">aerosols</span>. The daily average AOD at 550 nm is 0.16 (±0.09) and ranges between 0.05 and 0.80. A seasonal cycle is observed with minima in winter and maxima in spring-summer. High AOD days (above 0.3 at 550 nm) represent less than 10% of the totality of daily observations and correspond to the large scale advection of desert dust from Northern Africa or pollution <span class="hlt">aerosols</span> from Europe. The respective origin of the air masses is confirmed using FLEXPART simulations in the backward mode. Dust events are characterized by a large turbid <span class="hlt">layer</span> between 2 and 5 km <span class="hlt">height</span> while pollution events show a lower vertical development with a thick <span class="hlt">layer</span> below 3 km in altitude. However low level dust transport is also reported during spring while <span class="hlt">aerosol</span> pollution <span class="hlt">layer</span> between 2 and 4 km <span class="hlt">height</span> has been also observed. We report an effective lidar ratio at 355 nm for pollution <span class="hlt">aerosols</span> 68 (±13) Sr while it is 63 (±18) Sr for dust. The daily mean AOD at 355 nm for dust events is 0.61 (±0.14) and 0.71 (±0.16) for pollution <span class="hlt">aerosols</span> events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AtmRe.178..580G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AtmRe.178..580G&link_type=ABSTRACT"><span id="translatedtitle">Three-dimensional structure of <span class="hlt">aerosol</span> in China: A perspective from multi-satellite observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Jianping; Liu, Huan; Wang, Fu; Huang, Jingfeng; Xia, Feng; Lou, Mengyun; Wu, Yerong; Jiang, Jonathan H.; Xie, Tao; Zhaxi, Yangzong; Yung, Yuk L.</p> <p>2016-09-01</p> <p>Using eight years (2006-2014) of passive (MODIS/Aqua and OMI/Aura) and active (CALIOP/CALIPSO) satellite measurements of <span class="hlt">aerosols</span>, we yield a three-dimensional (3D) distribution of the frequency of occurrence (FoO) of <span class="hlt">aerosols</span> over China. As an indicator of the vertical heterogeneity of <span class="hlt">aerosol</span> <span class="hlt">layers</span> detected by CALIOP, two types of Most Probable <span class="hlt">Height</span> (MPH), including MPH_FoO and MPH_AOD, are deduced. The FoO of "Total <span class="hlt">Aerosol</span>" reveals significant geographical dependence. Eastern China showed much stronger <span class="hlt">aerosol</span> FoD than northwestern China. The FoO vertical structures of <span class="hlt">aerosol</span> <span class="hlt">layer</span> are strongly dependent on altitudes. Among the eight typical ROIs analyzed, <span class="hlt">aerosol</span> <span class="hlt">layers</span> over the Gobi Desert have the largest occurrence probability located at an altitude as high as 2.83 km, as compared to 1.26 km over Beijing-Tianjin-Hebei. The diurnal variation (nighttime-daytime) in MPH_AOD varies from an altitude as low as 0.07 km over the Sichuan basin to 0.27 km over the Gobi Desert, whereas the magnitude of the diurnal variation in terms of MPH_AOD is six times as large as the MPH_FoO, mostly attributable to the day/night lidar SNR difference. Also, the 3D distribution of dust and smoke <span class="hlt">aerosols</span> was presented. The multi-sensor synergized 3D observations of dust <span class="hlt">aerosols</span>, frequently observed in the zonal belt of 38°N-45°N, is markedly different from that of smoke <span class="hlt">aerosols</span> that are predominantly located in the eastern and southern parts. The 3D FoO distribution of dust indicates a west-to-east passageway of dust originating from the westernmost Taklimakan Desert all the way to North China Plain (NCP). The findings from the multi-sensor synergetic observations greatly improved our understanding on the long-range <span class="hlt">aerosol</span> dispersion, transport and passageway over China.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24881367','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24881367"><span id="translatedtitle">[A floating-dust case study based on the vertical distribution of <span class="hlt">aerosol</span> optical properties].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Yuan; Deng, Jun-Ying; Shi, Lan-Hong; Chen, Yong-Hang; Zhang, Qiang; Wang, Sheng; Xu, Ting-Ting</p> <p>2014-03-01</p> <p>The vertical distribution of <span class="hlt">aerosol</span> optical properties of a typical floating-dust event on October 19, 2009 in Shanghai was analyzed by using Micro-pulse Lidar (MPL) and the CALIPSO satellite. The results showed that the floating-dust <span class="hlt">aerosol</span> mainly existed below 2 km of <span class="hlt">height</span>. The floating-dust <span class="hlt">aerosol</span> backscatter coefficient ranged from 0 to 0.015 km(-1) x sr(-1), and the MPL extinction coefficient ranged from 0 to 0.32 km(-1). The MPL data showed that the <span class="hlt">aerosol</span> extinction coefficient first increased and then decreased during the floating-dust event. At the same time, the <span class="hlt">aerosol</span> <span class="hlt">layer</span> was constantly lifting. The CALIPSO data showed that a large number of small particles were suspended in air at a <span class="hlt">height</span> of below 2 km, while the big particles always stayed near the ground (0-0.5 km). At the <span class="hlt">height</span> of 2-10 km, there was only few <span class="hlt">aerosols</span>; in the range of 4-6 km, there was a mixture of particles with regular and irregular shapes. The vertical distribution of CALIPSO 532 nm total attenuated backscatter coefficient and MPL normalized relative backscatter signal was basically the same, but the extinction coefficient values gained by them were different. Observations by CALIPSO and MPL together could be more comprehensive and objective for monitoring floating-dust in Shanghai. PMID:24881367</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970001690','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970001690"><span id="translatedtitle">Radiative Effects of <span class="hlt">Aerosols</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Valero, Francisco P. J.</p> <p>1996-01-01</p> <p>During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in <span class="hlt">aerosol</span> optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size-resolved <span class="hlt">aerosol</span> microphysics and chemistry. Both profiles included a pollution haze from Europe but the second also included the effect of a Saharan dust <span class="hlt">layer</span> above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) <span class="hlt">aerosol</span> were determined and thermal analysis of the pollution haze indicated that the fine <span class="hlt">aerosol</span> was composed primarily of a sulfate/water mixture with a refractory soot-like core. The soot core increased the calculated extinction by about 10% in the most polluted drier <span class="hlt">layer</span> relative to a pure sulfate <span class="hlt">aerosol</span> but had significantly less effect at higher humidities. A 3 km descent through a boundary <span class="hlt">layer</span> air mass dominated by pollutant <span class="hlt">aerosol</span> with relative humidities (RH) 10-77% yielded a close agreement between the measured and calculated <span class="hlt">aerosol</span> optical depths (550 nm) of 0.160 (+/- 0.07) and 0. 157 (+/- 0.034) respectively. During descent the <span class="hlt">aerosol</span> mass scattering coefficient per unit sulfate mass varied from about 5 to 16 m(exp 2)/g and primarily dependent upon ambient RH. However, the total scattering coefficient per total fine mass was far less variable at about 4+/- 0.7 m(exp 2)/g. A subsequent descent through a Saharan dust <span class="hlt">layer</span> located above the pollution <span class="hlt">aerosol</span> <span class="hlt">layer</span> revealed that both <span class="hlt">layers</span> contributed similarly to <span class="hlt">aerosol</span> optical depth. The scattering per unit mass of the coarse aged dust was estimated at 1.1 +/- 0.2 m(exp 2)/g. The large difference (50%) in measured and calculated optical depth for the dust <span class="hlt">layer</span> exceeded measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22253205','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22253205"><span id="translatedtitle">Schottky barrier <span class="hlt">height</span> reduction for metal/n-InP by inserting ultra-thin atomic <span class="hlt">layer</span> deposited high-k dielectrics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zheng, Shan; Yang, Wen; Sun, Qing-Qing E-mail: linchen@fudan.edu.cn; Zhou, Peng; Wang, Peng-Fei; Wei Zhang, David; Chen, Lin; Xiao, Fei</p> <p>2013-12-23</p> <p>Fermi level pinning at metal/n-InP interface and effective Schottky barrier <span class="hlt">height</span> (Φ{sub B,eff}) were optimized by inserting ultrathin dielectrics in this work. Comparing the inserted monolayer and bilayer high-k dielectrics, we demonstrated that the introduction of bilayer dielectrics can further reduce Φ{sub B,eff} (from 0.49 eV to 0.22 eV) than the monolayer dielectric (from 0.49 eV to 0.32 eV) even though the overall dielectric thickness was thicker. The additional dipole formed at high-k/high-k interfaces could be used to expound the mechanism. This work proposed an effective solution to reduce resistance contacts for InP based transistors and Schottky barrier transistors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ACP....12.5963R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ACP....12.5963R"><span id="translatedtitle">The lofting of Western Pacific regional <span class="hlt">aerosol</span> by island thermodynamics as observed around Borneo</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robinson, N. H.; Allan, J. D.; Trembath, J. A.; Rosenberg, P. D.; Allen, G.; Coe, H.</p> <p>2012-07-01</p> <p>Vertical profiles of <span class="hlt">aerosol</span> chemical composition, number concentration and size were measured throughout the lower troposphere of Borneo, a large tropical island in the western Pacific Ocean. <span class="hlt">Aerosol</span> composition, size and number concentration measurements (using an Aerodyne <span class="hlt">Aerosol</span> Mass Spectrometer, Passive Cavity <span class="hlt">Aerosol</span> Spectrometer Probe and Condensation Particle Counter, respectively) were made both upwind and downwind of Borneo, as well as over the island itself, on board the UK BAe-146 research aircraft as part of the OP3 project. Two meteorological regimes were identified - one dominated by isolated terrestrial convection (ITC) which peaked in the afternoon, and the other characterised by more regionally active mesoscale convective systems (MCS). Upwind profiles show <span class="hlt">aerosol</span> to be confined to a shallow marine boundary <span class="hlt">layer</span> below 930 ± 10 hPa (~760 m above sea level, a.s.l.). As this air mass advects over the island with the mean free troposphere synoptic flow during the ITC-dominated regime, it is convectively lofted above the terrestrial surface mixed <span class="hlt">layer</span> to <span class="hlt">heights</span> of between 945 ± 22 (~630 m a.s.l.) and 740 ± 44 hPa (~2740 m a.s.l.), consistent with a coupling between the synoptic steering level flow and island sea breeze circulations. Terrestrial <span class="hlt">aerosol</span> was observed to be lofted into this higher <span class="hlt">layer</span> through both moist convective uplift and transport through turbulent diurnal sea-breeze cells. At the peak of convective activity in the mid-afternoons, organic <span class="hlt">aerosol</span> loadings in the lofted <span class="hlt">layer</span> were observed to be substantially higher than in the morning (by a mean factor of three). This organic matter is dominated by secondary <span class="hlt">aerosol</span> from processing of biogenic gas phase precursors. <span class="hlt">Aerosol</span> number concentration profiles suggest formation of new particles aloft in the atmosphere. By the time the air mass reaches the west coast of the island, terrestrial <span class="hlt">aerosol</span> is enhanced in the lofted <span class="hlt">layer</span>. Such uplift of <span class="hlt">aerosol</span> in Borneo is expected to</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMIN32A..02Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMIN32A..02Y"><span id="translatedtitle">Near Real Time Vertical Profiles of Clouds and <span class="hlt">Aerosols</span> from the Cloud-<span class="hlt">Aerosol</span> Transport System (CATS) on the International Space Station</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yorks, J. E.; McGill, M. J.; Nowottnick, E. P.</p> <p>2015-12-01</p> <p>Plumes from hazardous events, such as ash from volcanic eruptions and smoke from wildfires, can have a profound impact on the climate system, human health and the economy. Global <span class="hlt">aerosol</span> transport models are very useful for tracking hazardous plumes and predicting the transport of these plumes. However <span class="hlt">aerosol</span> vertical distributions and optical properties are a major weakness of global <span class="hlt">aerosol</span> transport models, yet a key component of tracking and forecasting smoke and ash. The Cloud-<span class="hlt">Aerosol</span> Transport System (CATS) is an elastic backscatter lidar designed to provide vertical profiles of clouds and <span class="hlt">aerosols</span> while also demonstrating new in-space technologies for future Earth Science missions. CATS has been operating on the Japanese Experiment Module - Exposed Facility (JEM-EF) of the International Space Station (ISS) since early February 2015. The ISS orbit provides more comprehensive coverage of the tropics and mid-latitudes than sun-synchronous orbiting sensors, with nearly a three-day repeat cycle. The ISS orbit also provides CATS with excellent coverage over the primary <span class="hlt">aerosol</span> transport tracks, mid-latitude storm tracks, and tropical convection. Data from CATS is used to derive properties of clouds and <span class="hlt">aerosols</span> including: <span class="hlt">layer</span> <span class="hlt">height</span>, <span class="hlt">layer</span> thickness, backscatter, optical depth, extinction, and depolarization-based discrimination of particle type. The measurements of atmospheric clouds and <span class="hlt">aerosols</span> provided by the CATS payload have demonstrated several science benefits. CATS provides near-real-time observations of cloud and <span class="hlt">aerosol</span> vertical distributions that can be used as inputs to global models. The infrastructure of the ISS allows CATS data to be captured, transmitted, and received at the CATS ground station within several minutes of data collection. The CATS backscatter and vertical feature mask are part of a customized near real time (NRT) product that the CATS processing team produces within 6 hours of collection. The continuous near real time CATS data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.4276E&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.4276E&link_type=ABSTRACT"><span id="translatedtitle">Observations of the Interaction and/or Transport of <span class="hlt">Aerosols</span> with Cloud or Fog during DRAGON Campaigns from AERONET Ground-Based Remote Sensing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eck, Thomas; Holben, Brent; Schafer, Joel; Giles, David; Kim, Jhoon; Kim, Young; Sano, Itaru; Reid, Jeffrey; Pickering, Kenneth; Crawford, James; Sinyuk, Alexander; Trevino, Nathan</p> <p>2014-05-01</p> <p>Ground-based remote sensing observations from <span class="hlt">Aerosol</span> Robotic Network (AERONET) sun-sky radiometers have recently shown several instances where cloud-<span class="hlt">aerosol</span> interaction had resulted in modification of <span class="hlt">aerosol</span> properties and/or in difficulty identifying some major pollution transport events due to <span class="hlt">aerosols</span> being imbedded in cloud systems. AERONET has established Distributed Regional <span class="hlt">Aerosol</span> Gridded Observation Networks (DRAGON) during field campaigns that are short-term (~2-3 months) relatively dense spatial networks of ~15 to 45 sun and sky scanning photometers. Recent major DRAGON field campaigns in Japan and South Korea (Spring 2012) and California (Winter 2013) have yielded observations of <span class="hlt">aerosol</span> transport associated with clouds and/or <span class="hlt">aerosol</span> properties modification as a result of fog interaction. Analysis of data from the Korean and Japan DRAGON campaigns shows that major fine-mode <span class="hlt">aerosol</span> transport events are sometimes associated with extensive cloud cover and that cloud-screening of observations often filter out significant pollution <span class="hlt">aerosol</span> transport events. The Spectral De-convolution Algorithm (SDA) algorithm was utilized to isolate and analyze the fine-mode <span class="hlt">aerosol</span> optical depth signal for these cases of persistent and extensive cloud cover. Additionally, extensive fog that was coincident with <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span> on some days in both Korea and California resulted in large increases in fine mode <span class="hlt">aerosol</span> radius, with a mode of cloud-processed or residual <span class="hlt">aerosol</span> of radius ~0.4-0.5 micron sometimes observed. Cloud processed <span class="hlt">aerosol</span> may occur much more frequently than AERONET data suggest due to inherent difficulty in observing <span class="hlt">aerosol</span> properties near clouds from remote sensing observations. These biases of <span class="hlt">aerosols</span> associated with clouds would likely be even greater for satellite remote sensing retrievals of <span class="hlt">aerosol</span> properties near clouds due to 3-D effects and sub-pixel cloud contamination issues.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AIPC.1100..315P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AIPC.1100..315P"><span id="translatedtitle">Monitoring <span class="hlt">Aerosol</span> Optical Properties in the ABL, Using Lidar System and Sunphotometer in Buenos Aires, Argentina</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pallotta, J.; Pawelko, E.; Otero, L.; Ristori, P.; D'Elia, R.; Gonzalez, F.; Dworniczak, J.; Vilar, O.; Quel, E.</p> <p>2009-03-01</p> <p>At the Lasers and Applications Research Center (CEILAP, CITEFA-CONICET, (34°33' S, 58°30' W), located in an industrial suburb of the metropolitan area (Villa Martelli, Buenos Aires, Argentina), operates a multiwavelength lidar, based on a Nd:Yag laser (Continuum Surelite III P-IV). This system emits in 1064, 532 and 355 nm simultaneously (10 Hz, 600 mJ @ 1064 nm) and allows the monitoring of the optical <span class="hlt">aerosols</span> properties in the atmospheric boundary <span class="hlt">layer</span> (ABL). On the same experimental site, an AERONET sunphotometer provides the AOT value. An analysis of boundary <span class="hlt">layer</span> behaviour in some relevant days of March, from the years 2004 to 2006 is presented. On the days analyzed, no <span class="hlt">aerosols</span> events and clouds were registered over the ABL. Evolutions of some characteristics of the ABL are presented, such as the <span class="hlt">height</span> of the boundary <span class="hlt">layer</span>, <span class="hlt">height</span> of entrainment zone (EZ) and the entrainment flux ratio.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22043663','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22043663"><span id="translatedtitle">LOSA-M2 <span class="hlt">aerosol</span> Raman lidar</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Balin, Yu S; Bairashin, G S; Kokhanenko, G P; Penner, I E; Samoilova, S V</p> <p>2011-10-31</p> <p>The scanning LOSA-M2 <span class="hlt">aerosol</span> Raman lidar, which is aimed at probing atmosphere at wavelengths of 532 and 1064 nm, is described. The backscattered light is received simultaneously in two regimes: analogue and photon-counting. Along with the signals of elastic light scattering at the initial wavelengths, a 607-nm Raman signal from molecular nitrogen is also recorded. It is shown that the <span class="hlt">height</span> range of atmosphere probing can be expanded from the near-Earth <span class="hlt">layer</span> to stratosphere using two (near- and far-field) receiving telescopes, and analogue and photon-counting lidar signals can be combined into one signal. Examples of natural measurements of <span class="hlt">aerosol</span> stratification in atmosphere along vertical and horizontal paths during the expeditions to the Gobi Desert (Mongolia) and Lake Baikal areas are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.7695M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ACP....16.7695M&link_type=ABSTRACT"><span id="translatedtitle">Contribution of dissolved organic matter to submicron water-soluble organic <span class="hlt">aerosols</span> in the marine boundary <span class="hlt">layer</span> over the eastern equatorial Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miyazaki, Yuzo; Coburn, Sean; Ono, Kaori; Ho, David T.; Pierce, R. Bradley; Kawamura, Kimitaka; Volkamer, Rainer</p> <p>2016-06-01</p> <p>Stable carbon isotopic compositions of water-soluble organic carbon (WSOC) and organic molecular markers were measured to investigate the relative contributions of the sea surface sources to the water-soluble fraction of submicron organic <span class="hlt">aerosols</span> collected over the eastern equatorial Pacific during the Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated VOCs (TORERO)/KA-12-01 cruise. On average, the water-soluble organic fraction of the total carbon (TC) mass in submicron <span class="hlt">aerosols</span> was ˜ 30-35 % in the oceans with the low chlorophyll a (Chl a) concentrations, whereas it was ˜ 60 % in the high-Chl a regions. The average stable carbon isotope ratio of WSOC (δ13CWSOC) was -19.8 ± 2.0 ‰, which was systematically higher than that of TC (δ13CTC) (-21.8 ± 1.4 ‰). We found that in the oceans with both high and low Chl a concentrations the δ13CWSOC was close to the typical values of δ13C for dissolved organic carbon (DOC), ranging from -22 to -20 ‰ in surface seawater of the tropical Pacific Ocean. This suggests an enrichment of marine biological products in WSOC <span class="hlt">aerosols</span> in the study region regardless of the oceanic area. In particular, enhanced levels of WSOC and biogenic organic marker compounds together with high values of WSOC / TC ( ˜ 60 %) and δ13CWSOC were observed over upwelling areas and phytoplankton blooms, which was attributed to planktonic tissues being more enriched in δ13C. The δ13C analysis estimated that, on average, marine sources contribute ˜ 90 ± 25 % of the <span class="hlt">aerosol</span> carbon, indicating the predominance of marine-derived carbon in the submicron WSOC. This conclusion is supported by Lagrangian trajectory analysis, which suggests that the majority of the sampling points on the ship had been exposed to marine boundary <span class="hlt">layer</span> (MBL) air for more than 80 % of the time during the previous 7 days. The combined analysis of the δ13C and monosaccharides, such as glucose and fructose, demonstrated that DOC concentration was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.4043H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.4043H"><span id="translatedtitle">Variability of CCN Activation Behaviour of <span class="hlt">Aerosol</span> Particles in the Marine Boundary <span class="hlt">Layer</span> of the Northern and Southern Atlantic Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Henning, Silvia; Dieckmann, Katrin; Hartmann, Susan; Schäfer, Michael; Wu, Zhijun; Merkel, Maik; Wiedensohler, Alfred; Stratmann, Frank</p> <p>2013-04-01</p> <p>The variability of cloud condensation nucleus (CCN) activation behaviour and total CCN number concentrations was investigated during three ship cruises. Measurements were performed in a mobile laboratory on the German research vessel FS Polarstern cruising between Cape Town and Bremerhaven (April / May and October / November 2011) as well as between Punta Arenas and Bremerhaven (April / May 2012). CCN size distributions were measured for supersaturations between 0.1% and 0.4% using a Cloud Condensation Nucleus Counter (DMT, USA). <span class="hlt">Aerosol</span> particle and CCN total number concentrations as well as the hygroscopicity parameter κ (Petters and Kreidenweis, 2007) were determined. Furthermore, size distribution data were collected. The hygroscopicity parameter κ featured a high variability during the cruises, with a median κ-value of 0.52 ± 0.26. The κ-values are depended on air mass origin; and are as expected mainly dominated by marine influences, but also long range transport of <span class="hlt">aerosol</span> particles was detected. In the Celtic Sea, κ was found to be lower than that of clean marine <span class="hlt">aerosol</span> particles (0.72 ± 0.24; Pringle et al., 2010) with κ-values ~0.2, possibly influenced by anthropogenic emissions from Europe. Close to the West African coast particle hygroscopicity was found to be influenced by the Saharan dust plume, resulting in low κ-values ~0.25. Petters, M.D. and S.M. Kreidenweis (2007), A single parameter representation of hygroscopic growth and cloud condensation nucleus activity, Atmos. Chem. and Phys., 7, 1961-1971. Pringle, K.J., H. Tost, A. Pozzer, U. Pöschl, and J. Lelieveld (2010), Global distribution of the effective <span class="hlt">aerosol</span> hygroscopicity parameter for CCN activation, Atmos. Chem. Phys., 10, 5241-5255.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACP....1512547M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACP....1512547M"><span id="translatedtitle">Ice nucleating particles at a coastal marine boundary <span class="hlt">layer</span> site: correlations with <span class="hlt">aerosol</span> type and meteorological conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mason, R. H.; Si, M.; Li, J.; Chou, C.; Dickie, R.; Toom-Sauntry, D.; Pöhlker, C.; Yakobi-Hancock, J. D.; Ladino, L. A.; Jones, K.; Leaitch, W. R.; Schiller, C. L.; Abbatt, J. P. D.; Huffman, J. A.; Bertram, A. K.</p> <p>2015-11-01</p> <p>Information on what <span class="hlt">aerosol</span> particle types are the major sources of ice nucleating particles (INPs) in the atmosphere is needed for climate predictions. To determine which <span class="hlt">aerosol</span> particles are the major sources of immersion-mode INPs at a coastal site in Western Canada, we investigated correlations between INP number concentrations and both concentrations of different atmospheric particles and meteorological conditions. We show that INP number concentrations are strongly correlated with the number concentrations of fluorescent bioparticles between -15 and -25 °C, and that the size distribution of INPs is most consistent with the size distribution of fluorescent bioparticles. We conclude that biological particles were likely the major source of ice nuclei at freezing temperatures between -15 and -25 °C at this site for the time period studied. At -30 °C, INP number concentrations are also well correlated with number concentrations of the total <span class="hlt">aerosol</span> particles ≥ 0.5 μm, suggesting that non-biological particles may have an important contribution to the population of INPs active at this temperature. As we found that black carbon particles were unlikely to be a major source of ice nuclei during this study, these non-biological INPs may include mineral dust. Furthermore, correlations involving chemical tracers of marine <span class="hlt">aerosols</span> and marine biological activity, sodium and methanesulfonic acid, indicate that the majority of INPs measured at the coastal site likely originated from terrestrial rather than marine sources. Finally, six existing empirical parameterizations of ice nucleation were tested to determine if they accurately predict the measured INP number concentrations. We found that none of the parameterizations selected are capable of predicting INP number concentrations with high accuracy over the entire temperature range investigated. This finding illustrates that additional measurements are needed to improve parameterizations of INPs and their</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACPD...1516273M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACPD...1516273M"><span id="translatedtitle">Ice nucleating particles at a coastal marine boundary <span class="hlt">layer</span> site: correlations with <span class="hlt">aerosol</span> type and meteorological conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mason, R. H.; Si, M.; Li, J.; Chou, C.; Dickie, R.; Toom-Sauntry, D.; Pöhlker, C.; Yakobi-Hancock, J. D.; Ladino, L. A.; Jones, K.; Leaitch, W. R.; Schiller, C. L.; Abbatt, J. P. D.; Huffman, J. A.; Bertram, A. K.</p> <p>2015-06-01</p> <p>Information on what <span class="hlt">aerosol</span> particle types are the major sources of ice nucleating particles (INPs) in the atmosphere is needed for climate predictions. To determine which <span class="hlt">aerosol</span> particles are the major sources of immersion-mode INPs at a coastal site in Western Canada, we investigated correlations between INP number concentrations and both concentrations of different atmospheric particles and meteorological conditions. We show that INP number concentrations are strongly correlated with the number concentrations of fluorescent bioparticles between -15 and -25 °C, and that the size distribution of INPs is most consistent with the size distribution of fluorescent bioparticles. We conclude that biological particles were likely the major source of ice nuclei at freezing temperatures between -15 and -25 °C at this site for the time period studied. At -30 °C, INP number concentrations are also well correlated with number concentrations of the total <span class="hlt">aerosol</span> particles ≥ 0.5 μm, suggesting that non-biological particles may have an important contribution to the population of INPs active at this temperature. As we found that black carbon particles were unlikely to be a major source of ice nuclei during this study, these non-biological INPs may include mineral dust. Furthermore, correlations involving tracers of marine <span class="hlt">aerosols</span> and marine biological activity indicate that the majority of INPs measured at the coastal site likely originated from terrestrial rather than marine sources. Finally, six existing empirical parameterizations of ice nucleation were tested to determine if they accurately predict the measured INP number concentrations. We found that none of the parameterizations selected are capable of predicting INP number concentrations with high accuracy over the entire temperature range investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150000271','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150000271"><span id="translatedtitle">Stereoscopic Retrieval of Smoke Plume <span class="hlt">Heights</span> and Motion from Space-Based Multi-Angle Imaging, Using the MISR INteractive eXplorer(MINX)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nelson, David L.; Kahn, Ralph A.</p> <p>2014-01-01</p> <p>Airborne particles desert dust, wildfire smoke, volcanic effluent, urban pollution affect Earth's climate as well as air quality and health. They are found in the atmosphere all over the planet, but vary immensely in amount and properties with season and location. Most <span class="hlt">aerosol</span> particles are injected into the near-surface boundary <span class="hlt">layer</span>, but some, especially wildfire smoke, desert dust and volcanic ash, can be injected higher into the atmosphere, where they can stay aloft longer, travel farther, produce larger climate effects, and possibly affect human and ecosystem health far downwind. So monitoring <span class="hlt">aerosol</span> injection <span class="hlt">height</span> globally can make important contributions to climate science and air quality studies. The Multi-angle Imaging Spectro-Radiometer (MISR) is a space borne instrument designed to study Earths clouds, <span class="hlt">aerosols</span>, and surface. Since late February 2000 it has been retrieving <span class="hlt">aerosol</span> particle amount and properties, as well as cloud <span class="hlt">height</span> and wind data, globally, about once per week. The MINX visualization and analysis tool complements the operational MISR data products, enabling users to retrieve <span class="hlt">heights</span> and winds locally for detailed studies of smoke plumes, at higher spatial resolution and with greater precision than the operational product and other space-based, passive remote sensing techniques. MINX software is being used to provide plume <span class="hlt">height</span> statistics for climatological studies as well as to investigate the dynamics of individual plumes, and to provide parameterizations for climate modeling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A21D3057C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFM.A21D3057C&link_type=ABSTRACT"><span id="translatedtitle">Estimation of global anthropogenic dust <span class="hlt">aerosol</span> using CALIOP satellite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, B.; Huang, J.; Liu, J.</p> <p>2014-12-01</p> <p>Anthropogenic dust <span class="hlt">aerosols</span> are those produced by human activity, which mainly come from cropland, pasture, and urban in this paper. Because understanding of the emissions of anthropogenic dust is still very limited, a new technique for separating anthropogenic dust from natural dustusing CALIPSO dust and planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> retrievalsalong with a land use dataset is introduced. Using this technique, the global distribution of dust is analyzed and the relative contribution of anthropogenic and natural dust sources to regional and global emissions are estimated. Local anthropogenic dust <span class="hlt">aerosol</span> due to human activity, such as agriculture, industrial activity, transportation, and overgrazing, accounts for about 22.3% of the global continentaldust load. Of these anthropogenic dust <span class="hlt">aerosols</span>, more than 52.5% come from semi-arid and semi-wet regions. On the whole, anthropogenic dust emissions from East China and India are higher than other regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040171157&hterms=coverage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcoverage','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040171157&hterms=coverage&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcoverage"><span id="translatedtitle">Cloud Coverage and <span class="hlt">Height</span> Distribution from the GLAS Polar Orbiting Lidar: Comparison to Passive Cloud Retrievals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spinhime, J. D.; Palm, S. P.; Hlavka, D. L.; Hart, W. D.; Mahesh, A.</p> <p>2004-01-01</p> <p>The Geoscience Laser Altimeter System (GLAS) began full on orbit operations in September 2003. A main application of the two-wavelength GLAS lidar is highly accurate detection and profiling of global cloud cover. Initial analysis indicates that cloud and <span class="hlt">aerosol</span> <span class="hlt">layers</span> are consistently detected on a global basis to cross-sections down to 10(exp -6) per meter. Images of the lidar data dramatically and accurately show the vertical structure of cloud and <span class="hlt">aerosol</span> to the limit of signal attenuation. The GLAS lidar has made the most accurate measurement of global cloud coverage and <span class="hlt">height</span> to date. In addition to the calibrated lidar signal, GLAS data products include multi level boundaries and optical depth of all transmissive <span class="hlt">layers</span>. Processing includes a multi-variable separation of cloud and <span class="hlt">aerosol</span> <span class="hlt">layers</span>. An initial application of the data results is to compare monthly cloud means from several months of GLAS observations in 2003 to existing cloud climatologies from other satellite measurement. In some cases direct comparison to passive cloud retrievals is possible. A limitation of the lidar measurements is nadir only sampling. However monthly means exhibit reasonably good global statistics and coverage results, at other than polar regions, compare well with other measurements but show significant differences in <span class="hlt">height</span> distribution. For polar regions where passive cloud retrievals are problematic and where orbit track density is greatest, the GLAS results are particularly an advance in cloud cover information. Direct comparison to MODIS retrievals show a better than 90% agreement in cloud detection for daytime, but less than 60% at night. <span class="hlt">Height</span> retrievals are in much less agreement. GLAS is a part of the NASA EOS project and data products are thus openly available to the science community (see http://glo.gsfc.nasa.gov).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009AGUFM.A42D..05V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009AGUFM.A42D..05V&link_type=ABSTRACT"><span id="translatedtitle">A Parameterization of Wildfire Emission Injection <span class="hlt">Heights</span> in North America: Analysis from Satellite Observations and Models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Val Martin, M.; Logan, J. A.; Kahn, R. A.; Ichoku, C. M.; Freitas, S. R.; Cantin, A.</p> <p>2009-12-01</p> <p>Fire emissions can be injected above the boundary <span class="hlt">layer</span> due to strong buoyancy generated from the fires, with important implications for long-range transport of these emissions and their effects on atmospheric composition. A multi-year record of <span class="hlt">aerosol</span> smoke plume <span class="hlt">heights</span> derived from observations made by the NASA Terra Multi-angle Imaging SpectroRadiometer (MISR) shows that fire smoke injection <span class="hlt">heights</span> in the North American biomes are highly variable, ranging from a few hundred meters to 5000 m above the terrain, at the Terra overpass time. The analysis of plume <span class="hlt">heights</span> with assimilated meteorological observations from the NASA Goddard Earth Observing System and measurements of the MODerate resolution Imaging Spectroradiometer (MODIS) fire radiative power (FRP) indicates the important effect of both buoyancy generated by the fires and local atmospheric structure on the ultimate rise of these fire emissions. Here, we evaluate a 1-D plume-rise model, driven by MODIS-based fire properties and local meteorology, using the MISR smoke plume <span class="hlt">height</span> dataset as a constraint. We also use the 1-D plume-rise model to investigate the effect of the diurnal variation of these physical processes on the injection <span class="hlt">heights</span>. A non-computationally expensive parametrization of fire emission injection <span class="hlt">heights</span> over North America for chemical transport models is discussed, and preliminary results using the 3-D global chemistry transport model GEOS-Chem during the ARCTAS campaign are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJWC.11916016H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJWC.11916016H"><span id="translatedtitle">Use of Lidar Derived Optical Extinction and Backscattering Coefficients Near Cloud Base to Explore <span class="hlt">Aerosol</span>-Cloud Interactions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Han, Zaw; Wu, Yonhgua; Gross, Barry; Moshary, Fred</p> <p>2016-06-01</p> <p>Combination of microwave radiometer (MWR) and mutlifilter rotating shadowband radiometer (MFRSR) measurement data together with SBDART radiative transfer model to compute cloud optical depth (COD) and cloud droplet effective radius (Reff). Quantify the first <span class="hlt">aerosol</span> indirect effect using calculated Reff and <span class="hlt">aerosol</span> extinction from Raman lidar measurement in urban coastal region. Illustrate comparison between ground-based and satellite retrievals. Demonstrate relationship between surface <span class="hlt">aerosol</span> (PM2.5) loading and Reff. We also explain the sensitivity of <span class="hlt">aerosol</span>-cloud-index (ACI) depend on the <span class="hlt">aerosol</span> <span class="hlt">layer</span> from cloud base <span class="hlt">height</span>. Potential used of less noisy elastic backscattering to calculate the ACI instead of using Raman extinction. We also present comparison of elastic backscattering and Raman extinction correlation to Reff.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.A41E..07K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.A41E..07K"><span id="translatedtitle">Natural and Anthropogenic <span class="hlt">Aerosols</span> in the World's Megacities and Climate Impacts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kafatos, M.; Singh, R.; El-Askary, H.; Qu, J.</p> <p>2005-12-01</p> <p> <span class="hlt">aerosols</span>. The highest boundary <span class="hlt">layer</span> <span class="hlt">heights</span> are associated with regions where the sensible heat flux is greatest, and latent heat flux is smallest due to lack of vegetation. Boundary <span class="hlt">layer</span> <span class="hlt">heights</span> in the deserts may be systematically higher than the slightly wetter regions at the edges of deserts. Latent heat flux model runs and MODIS observations of dust storms affecting the Nile Delta and Cairo indicate strong influence on the local weather and climate forcings. In the Indo-Gangetic, during the pre-monsoon period, dust storms form. We have examined SDS transport using RS data acquired from NASA's MODIS MISR instruments and from sun photometer measurements. The <span class="hlt">aerosol</span> optical depth and size of the dust particles are found to be significantly higher during such dust storm events. Moreover, our results clearly show that power plants in this region are the key point source of air pollutants. The detailed analysis of <span class="hlt">aerosol</span> parameters show the existence of absorbing and non-absorbing <span class="hlt">aerosols</span> emitted from these plants. The combined effects of urban <span class="hlt">aerosols</span> with dust <span class="hlt">aerosols</span> in India and Cairo not only affect megacities, they also have long-term climate impacts. We will also discuss how the assimilation of RS data into mesoscale models can improve these models and predictability of hazards and effects on megacities, such as SDS events, and forest fires, all sources of <span class="hlt">aerosols</span>. Therefore RS data can improve the prediction of climate forcings by <span class="hlt">aerosols</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26969552','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26969552"><span id="translatedtitle">Analysis of the origin of peak <span class="hlt">aerosol</span> optical depth in springtime over the Gulf of Tonkin.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shan, Xiaoli; Xu, Jun; Li, Yixue; Han, Feng; Du, Xiaohui; Mao, Jingying; Chen, Yunbo; He, Youjiang; Meng, Fan; Dai, Xuezhi</p> <p>2016-02-01</p> <p>By aggregating MODIS (moderate-resolution imaging spectroradiometer) AOD (<span class="hlt">aerosol</span> optical depth) and OMI (ozone monitoring instrument) UVAI (ultra violet <span class="hlt">aerosol</span> index) datasets over 2010-2014, it was found that peak <span class="hlt">aerosol</span> loading in seasonal variation occurred annually in spring over the Gulf of Tonkin (17-23 °N, 105-110 °E). The vertical structure of the <span class="hlt">aerosol</span> extinction coefficient retrieved from the spaceborne lidar CALIOP (cloud-<span class="hlt">aerosol</span> lidar with orthogonal polarization) showed that the springtime peak AOD could be attributed to an abrupt increase in <span class="hlt">aerosol</span> loading between altitudes of 2 and 5 km. In contrast, <span class="hlt">aerosol</span> loading in the low atmosphere (below 1 km) was only half of that in winter. Wind fields in the low and high atmosphere exhibited opposite transportation patterns in spring over the Gulf of Tonkin, implying different sources for each level. By comparing the emission inventory of anthropogenic sources with biomass burning, and analyzing the seasonal variation of the vertical structure of <span class="hlt">aerosols</span> over the Northern Indo-China Peninsula (NIC), it was concluded that biomass burning emissions contributed to high <span class="hlt">aerosol</span> loading in spring. The relatively high topography and the high surface temperature in spring made planetary boundary <span class="hlt">layer</span> <span class="hlt">height</span> greater than 3 km over NIC. In addition, small-scale cumulus convection frequently occurred, facilitating pollutant rising to over 3 km, which was a <span class="hlt">height</span> favoring long-range transport. Thus, pollutants emitted from biomass burning over NIC in spring were raised to the high atmosphere, then experienced long-range transport, leading to the increase in <span class="hlt">aerosol</span> loading at high altitudes over the Gulf of Tonkin during spring. PMID:26969552</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRD..119.4836G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRD..119.4836G"><span id="translatedtitle">Retrieving <span class="hlt">aerosol</span> microphysical properties by Lidar-Radiometer Inversion Code (LIRIC) for different <span class="hlt">aerosol</span> types</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Granados-Muñoz, M. J.; Guerrero-Rascado, J. L.; Bravo-Aranda, J. A.; Navas-Guzmán, F.; Valenzuela, A.; Lyamani, H.; Chaikovsky, A.; Wandinger, U.; Ansmann, A.; Dubovik, O.; Grudo, J. O.; Alados-Arboledas, L.</p> <p>2014-04-01</p> <p>LIRIC (Lidar-Radiometer Inversion Code) is applied to combined lidar and Sun photometer data from Granada station corresponding to different case studies. The main aim of this analysis is to evaluate the stability of LIRIC output volume concentration profiles for different <span class="hlt">aerosol</span> types, loadings, and vertical distributions of the atmospheric <span class="hlt">aerosols</span>. For this purpose, in a first part, three case studies corresponding to different atmospheric situations are analyzed to study the influence of the user-defined input parameters in LIRIC when varied in a reasonable range. Results evidence the capabilities of LIRIC to retrieve vertical profiles of microphysical properties during daytime by the combination of the lidar and the Sun photometer systems in an automatic and self-consistent way. However, spurious values may be obtained in the lidar incomplete overlap region depending on the structure of the <span class="hlt">aerosol</span> <span class="hlt">layers</span>. In a second part, the use of a second Sun photometer located in Cerro Poyos, in the same atmospheric column as Granada but at higher altitude, allowed us to obtain LIRIC retrievals from two different altitudes with independent Sun photometer measurements in order to check the self-consistency and robustness of the method. Retrievals at both levels are compared, providing a very good agreement (differences below 5 µm3/cm3) in those cases with the same <span class="hlt">aerosol</span> type in the whole atmospheric column. However, some assumptions such as the <span class="hlt">height</span> independency of parameters (sphericity, size distribution, or refractive index, among others) need to be carefully reviewed for those cases with the presence of <span class="hlt">aerosol</span> <span class="hlt">layers</span> corresponding to different types of atmospheric <span class="hlt">aerosols</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMSA21A0252R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMSA21A0252R"><span id="translatedtitle">Mass-analysis of Charged <span class="hlt">Aerosol</span> Particles in a PMSE/NLC <span class="hlt">Layer</span> by a Rocket-borne Spectrometer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robertson, S.; Horanyi, M.; Knappmiller, S.; Kohnert, R.; Sternovsky, Z.; Holzworth, R.; Shimogawa, M.; Friedrich, M.; Gumbel, J.; Khaplanov, M.; Megner, L.; Baumgarten, G.; Latteck, R.; Rapp, M.; Hoppe, U.</p> <p>2007-12-01</p> <p>The first of two "MASS" (Mesospheric <span class="hlt">Aerosol</span> Sampling Spectrometer) rockets was launched from the Andoya Rocket Range at 22:51 UTC on 3 August 2007 into PMSE and NLC approximately 26 minutes after an AIM satellite overpass. The sun was 4 degrees below the horizon and the local riometer indicated that the ionospheric conditions were rather quiet, i.e., day time conditions as far as negative cluster ions are concerned. NLC were seen in the previous hour at 83 km by the ALOMAR RMR lidar pointed along the rocket trajectory and were detected at the same altitude by rocket-borne photometer measurements. The rocket carried an electrostatic mass analyzer for the charged fraction of the <span class="hlt">aerosol</span> particles and both forward and aft deployable electric field booms. The mass analyzer was mounted on the tip of the payload and pointed in the ram direction. It has a forward inlet slit with area of 25 square centimeters and side vents for air exit. <span class="hlt">Aerosol</span> particles with different ranges of charge-to-mass ratio are collected within the instrument housing on two sets of four biased collector plates, with one set for positive particles and one set for negative particles. A preliminary analysis of the data shows the density of negative particles with radius greater than 3 nm rising sharply at 83 and continuing to 89 km, collocated with PMSE detected by the ALWIN radar. Particles with 1-2 nm radii with both signs of charge and positive particles with less than1 nm radius were detected at 86-88 km. Initial charge-density estimates are several thousands per cubic centimeter for each of these size ranges. The E field booms detected significant potential variations in the PMSE/NLC region. Further analysis will examine in more detail the effects of aerodynamics, payload charging, and spurious charge generation by particle impacts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1612487K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1612487K"><span id="translatedtitle">Global profiles of the direct <span class="hlt">aerosol</span> effect using vertically resolved <span class="hlt">aerosol</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Korras Carraca, Marios Bruno; Pappas, Vasilios; Matsoukas, Christos; Hatzianastassiou, Nikolaos; Vardavas, Ilias</p> <p>2014-05-01</p> <p> vertical <span class="hlt">layers</span> from the ground level up to 50 mb. This is the first study to our knowledge that provides vertically resolved all-sky DRE globally. We find that the columnar global average value of the CALIOP optical depth at 500 nm is 0.0815. The DRE at the surface is -3.14 Wm-2 (net) and -3.82 Wm-2 (downwelling), at the top of the atmosphere it is -1.21 Wm-2, and in the atmosphere 1.94 Wm-2. As expected however, very large local and seasonal differences from these values are found if one focuses on specific locations and months. Preliminary results show that that there are notable differences in the DRE produced by our radiation transfer model with vertically resolved <span class="hlt">aerosol</span> profiles compared with columnar values over some cloudy areas, depending on the <span class="hlt">aerosol</span> <span class="hlt">height</span> relatively to the clouds. We examine more closely the interplay of radiation fluxes between <span class="hlt">aerosol</span> and clouds for a few interesting cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.6066B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.6066B"><span id="translatedtitle"><span class="hlt">Aerosols</span> in GEOS-5: simulations of the UV <span class="hlt">Aerosol</span> Index and the <span class="hlt">Aerosol</span> Absorption Optical Depth and comparisons with OMI retrievals.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buchard-Marchant, Virginie; da Silva, Arlindo; Colarco, Peter; Darmenov, Anton; Govindaraju, Ravi</p> <p>2013-04-01</p> <p>GEOS-5 is the latest version of the NASA Global Modeling and Assimilation Office (GMAO) earth system model. GEOS-5 contains components for atmospheric circulation and composition (including data assimilation), ocean circulation and biogeochemistry, and land surface processes. In addition to traditional meteorological parameters, GEOS-5 includes modules representing the atmospheric composition, most notably <span class="hlt">aerosols</span> and tropospheric/stratospheric chemical constituents, taking explicit account of the impact of these constituents on the radiative processes of the atmosphere. The assimilation of <span class="hlt">Aerosol</span> Optical Depth (AOD) in GEOS-5 involves very careful cloud screening and homogenization of the observing system by means of a Neural Net scheme that translates MODIS radiances into AERONET calibrated AOD. These measurements are further quality controlled using an adaptive buddy check scheme, and assimilated using the Local Displacement Ensemble (LDE) methodology. For this analysis, GEOS-5 runs at a nominal 50km horizontal resolution with 72 vertical <span class="hlt">layers</span> (top at ~85km). GEOS-5 is driven by daily biomass burning emissions derived from MODIS fire radiative power retrievals. We present a summary of our efforts to simulate the UV <span class="hlt">Aerosol</span> Index (AI) at 354 nm from <span class="hlt">aerosol</span> simulations by performing a radiative transfer calculation. We have compared model produced AI with the corresponding OMI measurements, identifying regions where the model representation of absorbing <span class="hlt">aerosols</span> were deficient. Separately, model derived Absorption <span class="hlt">Aerosol</span> Optical Depth (AAOD) is compared with OMI retrievals. Making use of CALIPSO measurements we have also investigated the impact of the altitude of the <span class="hlt">aerosol</span> <span class="hlt">layer</span> on OMI derived AI trying to ascertain misplacement of plume <span class="hlt">height</span> by the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20150005512&hterms=organic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dorganic','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20150005512&hterms=organic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dorganic"><span id="translatedtitle">The Organic <span class="hlt">Aerosols</span> of Titan's Atmosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sotin, Christophe; Lawrence, Kenneth; Beauchamp, Patricia M.; Zimmerman, Wayne</p> <p>2012-01-01</p> <p>One of Titan's many characteristics is the presence of a haze that veils its surface. This haze is composed of heavy organic particles and determining the chemical composition of these particles is a primary objective for future probes that would conduct in situ analysis. Meanwhile, solar occultations provide constraints on the optical characteristics of the haze <span class="hlt">layer</span>. This paper describes solar occultation observations obtained by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft. These observations strongly constrain the optical characteristics of the haze <span class="hlt">layer</span>. We detail the different steps involved in the processing of these data and apply them to two occultations that were observed at the South Pole and at the equator in order to investigate the latitudinal dependence of optical properties. The light curves obtained in seven atmospheric windows between 0.933-microns to 5-microns allow us to characterize atmospheric <span class="hlt">layers</span> from 300 km to the surface. Very good fits of the light curves are obtained using a simple profile of number density of <span class="hlt">aerosols</span> that is characterized by a scale <span class="hlt">height</span>. The main difference between the South Pole and the equator is that the value of the scale <span class="hlt">height</span> increases with altitude at the South Pole whereas it decreases at the equator. The vertically integrated amount of <span class="hlt">aerosols</span> is similar at the two locations. The curve describing the cross-section versus wavelength is identical at the two locations suggesting that the <span class="hlt">aerosols</span> have similar characteristics. Finally, we find that the two-way vertical transmission at 5-microns is as large as 80% at both locations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JASTP.132..101M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JASTP.132..101M"><span id="translatedtitle">Comparison of peak <span class="hlt">height</span> of the F2-<span class="hlt">layer</span> (hmF2) measurements with IRI-2012, IRI-2007 and IRI-2001 models predictions above Roquetes station (Spain) during the ascending phase of the solar cycle 24</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mohammed, Fahmi A.</p> <p>2015-09-01</p> <p>This research aims to validate IRI-2012 program and examine its accuracy in predicting peak <span class="hlt">height</span> of the F2- <span class="hlt">layer</span> (hmF2) above Roquetes. The seasonal hourly means of the ionosphere F2 peak <span class="hlt">height</span> parameter (hmF2) above Roquetes station, Spain, (located at latitude close to the latitude of Iraq, 41°N) were analyzed and the results were compared with IRI-2012, IRI-2007 and IRI-2001, using CCIR (Comite´ Consultatif International des Radio Communications) option. The analysis covered quiet and disturbed days during various seasons of 2013 (the ascending phase of the solar cycle 24). In general, it is found that the predicted values of hmF2 overestimate the observed ones during all seasons, except Summer, whereas it underestimate at day hours. Also, it is found that the maximum percentage relative deviation of hmF2 occurred during Winter at 8 LT, while the minimum occurred during Autumnat 22 LT.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/15001986','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/15001986"><span id="translatedtitle">Comparison of <span class="hlt">Aerosol</span> Properties Within and Above the ABL at the ARM Program's SGP Site</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Delle Monache, L</p> <p>2002-05-01</p> <p>The goal of this thesis is to determine under what conditions, if any, measurements of <span class="hlt">aerosol</span> properties made at the Earth's surface are representative of <span class="hlt">aerosol</span> properties within the column of air above the surface. This thesis will use data from the Atmospheric Radiation Measurement (ARM) site at the Southern Great Plains (SGP) which is the only location in the world where ground-based and in situ airborne measurements are made on a routine basis. All flight legs in the one-year period from March 2000-March 2001 were categorized as either within or above the atmospheric boundary <span class="hlt">layer</span> using an objective mixing <span class="hlt">height</span> determination technique. The correlations between the <span class="hlt">aerosol</span> properties measured at the surface and the measured within and above the ABL were then computed. The conclusion of this comparison is that the <span class="hlt">aerosol</span> extensive and intensive properties measured at the surface are representative of values within the ABL, but not within the free atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1527..555K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1527..555K"><span id="translatedtitle">Modeling of microphysics and optics of <span class="hlt">aerosol</span> particles in the marine environments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaloshin, Gennady</p> <p>2013-05-01</p> <p>We present a microphysical model for the surface <span class="hlt">layer</span> marine and coastal atmospheric <span class="hlt">aerosols</span> that is based on long-term observations of size distributions for 0.01-100 μm particles. The fundamental feature of the model is a parameterization of amplitudes and widths for <span class="hlt">aerosol</span> modes of the <span class="hlt">aerosol</span> size distribution function (ASDF) as functions of fetch and wind speed. The shape of ASDF and its dependence on meteorological parameters, <span class="hlt">height</span> above sea level (H), fetch (X), wind speed (U) and relative humidity (RH), are investigated. At present, the model covers the ranges H = 0 - 25 m, U = 3 - 18 km s-1, X ≤ 120 km and RH = 40 - 98%. The latest version of the Marine <span class="hlt">Aerosol</span> Extinction Profiles model (MaexPro) is described and applied for the computation and analysis of the spectral profiles of <span class="hlt">aerosol</span> extinction coefficients α(λ) in the wavelength band λ = 0.2-12 μm. MaexPro is based on the aforementioned <span class="hlt">aerosol</span> model assuming spherically shaped <span class="hlt">aerosol</span> particles and the well-known Mie theory. The spectral profiles of α(λ) calculated by MaexPro are in good agreement with observational data and the numerical results. Moreover, MaexPro was found to be an accurate and reliable tool for investigating the optical properties of atmospheric <span class="hlt">aerosols</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.A43A0135N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.A43A0135N"><span id="translatedtitle">Boundary <span class="hlt">Layer</span> Observations of Water Vapor and <span class="hlt">Aerosol</span> Profiles with an Eye-Safe Micro-Pulse Differential Absorption Lidar (DIAL)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nehrir, A. R.; Repasky, K. S.; Carlsten, J.; Ismail, S.</p> <p>2011-12-01</p> <p>Measurements of real-time high spatial and temporal resolution profiles of combined water vapor and <span class="hlt">aerosols</span> in the boundary <span class="hlt">layer</span> have been a long standing observational challenge to the meteorological, weather forecasting, and climate science communities. To overcome the high reoccurring costs associated with radiosondes as well as the lack of sufficient water vapor measurements over the continental united states, a compact and low cost eye-safe all semiconductor-based micro-pulse differential absorption lidar (DIAL) has been developed for water vapor and <span class="hlt">aerosol</span> profiling in the lower troposphere. The laser transmitter utilizes two continuous wave external cavity diode lasers operating in the 830 nm absorption band as the online and offline seed laser sources. An optical switch is used to sequentially injection seed a tapered semiconductor optical amplifier (TSOA) with the two seed laser sources in a master oscillator power amplifier (MOPA) configuration. The TSOA is actively current pulsed to produce up to 7 μJ of output energy over a 1 μs pulse duration (150 m vertical resolution) at a 10 kHz pulse repetition frequency. The measured laser transmitter spectral linewidth is less than 500 kHz while the long term frequency stability of the stabilized on-line wavelength is ± 55 MHz. The laser transmitter spectral purity was measured to be greater than 0.9996, allowing for simultaneous measurements of water vapor in the lower and upper troposphere. The DIAL receiver utilizes a commercially available full sky-scanning capable 35 cm Schmidt-Cassegrain telescope to collect the scattered light from the laser transmitter. Light collected by the telescope is spectrally filtered to suppress background noise and is coupled into a fiber optic cable which acts as the system field stop and limits the full angle field of view to 140 μrad. The light is sampled by a fiber coupled APD operated in a Geiger mode. The DIAL instrument is operated autonomously where water vapor and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACP....15.2387Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACP....15.2387Z"><span id="translatedtitle">Simulating <span class="hlt">aerosol</span>-radiation-cloud feedbacks on meteorology and air quality over eastern China under severe haze conditionsin winter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, B.; Wang, Y.; Hao, J.</p> <p>2015-03-01</p> <p>The <span class="hlt">aerosol</span>-radiation-cloud feedbacks on meteorology and air quality over eastern China under severe winter haze conditions in January 2013 are simulated using the fully coupled online Weather Research and Forecasting/Chemistry (WRF-Chem) model. Three simulation scenarios including different <span class="hlt">aerosol</span> configurations are undertaken to distinguish the <span class="hlt">aerosol</span>'s radiative (direct and semi-direct) and indirect effects. Simulated spatial and temporal variations of PM2.5 are generally consistent with surface observations, with a mean bias of -18.9 μg m-3 (-15.0%) averaged over 71 big cities in China. Comparisons between different scenarios reveal that <span class="hlt">aerosol</span> radiative effects (direct effect and semi-direct effects) result in reductions of downward shortwave flux at the surface, 2 m temperature, 10 m wind speed and planetary boundary <span class="hlt">layer</span> (PBL) <span class="hlt">height</span> by up to 84.0 W m-2, 3.2°C, 0.8 m s-1, and 268 m, respectively. The simulated impact of the <span class="hlt">aerosol</span> indirect effects is comparatively smaller. Through reducing the PBL <span class="hlt">height</span> and stabilizing lower atmosphere, the <span class="hlt">aerosol</span> effects lead to increases in surface concentrations of primary pollutants (CO and SO2). Surface O3 mixing ratio is reduced by up to 6.9 ppb (parts per billion) due to reduced incoming solar radiation and lower temperature, while the <span class="hlt">aerosol</span> feedbacks on PM2.5 mass concentrations show some spatial variations. Comparisons of model results with observations show that inclusion of <span class="hlt">aerosol</span> feedbacks in the model significantly improves model performance in simulating meteorological variables and improves simulations of PM2.5 temporal distributions over the North China Plain, the Yangtze River delta, the Pearl River delta, and central China. Although the <span class="hlt">aerosol</span>-radiation-cloud feedbacks on <span class="hlt">aerosol</span> mass concentrations are subject to uncertainties, this work demonstrates the significance of <span class="hlt">aerosol</span>-radiation-cloud feedbacks for real-time air quality forecasting under haze conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830003273&hterms=Mount+St+Helens&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2528%2528Mount%2BSt%2529%2BHelens%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830003273&hterms=Mount+St+Helens&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2528%2528Mount%2BSt%2529%2BHelens%2529"><span id="translatedtitle">SAGE measurements of Mount St. Helens volcanic <span class="hlt">aerosols</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kent, G. S.</p> <p>1982-01-01</p> <p>The SAGE satellite system was used to make measurements on the optical extinction produced by stratospheric <span class="hlt">aerosols</span> from the Mount St. Helens eruption. Two periods of observation were analyzed. In the first period (May 21 to 31, 1980), SAGE moved southward from latitude 60 N, and crossed the United States approximately one week after the May 18th eruption. Enhancements in stratospheric extinction were confined to latitudes between about 55 N and 25 N and longitudes between 10 W and 140 W. Individual <span class="hlt">layers</span> were observed up to altitudes of 23 km. The geographical location of these <span class="hlt">layers</span> corresponded closely to that expected on the basis of high-altitude meteorological data. During June and much of July, SAGE was, by reason of its geographical position and other orbital characteristics, unable to make further measurements on the northern hemisphere. Between July 19th and August 12th a second southward pass over the northern hemisphere occurred and further observations were made. The volcanic <span class="hlt">aerosol</span> in the stratosphere was now found to be widely distributed over the hemisphere, the maximum concentrations being north of 50 N. The <span class="hlt">aerosol</span> showed considerable inhomogeneity and had reached as far south as 15 N but little, if any, had crossed the equator into the southern hemisphere. Individual <span class="hlt">layers</span> at different <span class="hlt">heights</span> were still distinguishable. The total stratospheric <span class="hlt">aerosol</span> loading on this occasion appeared to be greater than in May and corresponded to an increase in global stratospheric mass of between 50 and 100 percent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900042548&hterms=ssh&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dssh','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900042548&hterms=ssh&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dssh"><span id="translatedtitle">Effects of <span class="hlt">height</span> acceleration on Geosat <span class="hlt">heights</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hancock, David W., III; Brooks, Ronald L.; Lockwood, Dennis W.</p> <p>1990-01-01</p> <p>A radar altimeter tracking loop, such as that utilized by Geosat, produces <span class="hlt">height</span> errors in the presence of persistent <span class="hlt">height</span> acceleration h(a). The correction factor for the <span class="hlt">height</span> error is a function of both the loop feedback parameters and the <span class="hlt">height</span> acceleration. The correction, in meters, to the sea-surface <span class="hlt">height</span> (SSH) derived from Geosat is -0.16 h(a), where h(a) is in m/sec per sec. The errors induced by accelerations are produced primarily by changes in along-track geoid slopes. The nearly circular Geosat orbit and dynamic ocean topography produce small h(a) values. One area studied in detail encompasses the Marianas Trench and the Challenger Deep in the west central Pacific Ocean. Histograms of SSH corrections due to range accelerations have also been determined from 24-hour segments of Geosat global data. The findings are that 20 percent of the Geosat measurements have acceleration-induced errors of 2 cm or more, while 8 percent have errors of 3 cm or more.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22476111','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22476111"><span id="translatedtitle">Single and multi-<span class="hlt">layered</span> core-shell structures based on ZnO nanorods obtained by <span class="hlt">aerosol</span> assisted chemical vapor deposition</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C.; Miki-Yoshida, M.</p> <p>2015-07-15</p> <p>Core–shell nanorod structures were prepared by a sequential synthesis using an <span class="hlt">aerosol</span> assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO{sub 2} film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform <span class="hlt">layer</span> consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MO{sub x}/ZnO nanorod core–shell structures, where MO{sub x} was the metal oxide shell. Additionally, a three-<span class="hlt">layer</span> core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO{sub 2} as anatase. For the multi-<span class="hlt">layered</span> shell sample, the existence of Fe{sub 2}O{sub 3} as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide <span class="hlt">layers</span> are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-<span class="hlt">layered</span> sample, the development of a shell consisting of three different oxide <span class="hlt">layers</span> onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110004374','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110004374"><span id="translatedtitle">Comparison of Summer and Winter California Central Valley <span class="hlt">Aerosol</span> Distributions from Lidar and MODIS Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lewis, Jasper R., Jr.; DeYoung, Russell J.; Chu, D. Allen</p> <p>2010-01-01</p> <p><span class="hlt">Aerosol</span> distributions from two aircraft lidar campaigns conducted in the California Central Valley are compared in order to identify seasonal variations. Aircraft lidar flights were conducted in June 2003 and February 2008. While the PM2.5 concentration is highest in the winter, the <span class="hlt">aerosol</span> optical depth measured from MODIS is highest in the summer. A seasonal comparison shows that PM2.5 in the winter can exceed summer PM2.5 by 55%, while summer AOD exceeds winter AOD by 43%. Higher temperatures wildfires in the summer produce elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span> that are detected by satellite measurements, but not surface particulate matter monitors. Measurements of the boundary <span class="hlt">layer</span> <span class="hlt">height</span> from lidar instruments are necessary to incorporate satellite measurements with air quality measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.7368G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.7368G"><span id="translatedtitle">Absolute calibration of the Jenoptik CHM15k-x ceilometer and its applicability for quantitative <span class="hlt">aerosol</span> monitoring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geiß, Alexander; Wiegner, Matthias</p> <p>2014-05-01</p> <p>The knowledge of the spatiotemporal distribution of atmospheric <span class="hlt">aerosols</span> and its optical characterization is essential for the understanding of the radiation budget, air quality, and climate. For this purpose, lidar is an excellent system as it is an active remote sensing technique. As multi-wavelength research lidars with depolarization channels are quite complex and cost-expensive, increasing attention is paid to so-called ceilometers. They are simple one-wavelength backscatter lidars with low pulse energy for eye-safe operation. As maintenance costs are low and continuous and unattended measurements can be performed, they are suitable for long-term <span class="hlt">aerosol</span> monitoring in a network. However, the signal-to-noise ratio is low, and the signals are not calibrated. The only optical property that can be derived from a ceilometer is the particle backscatter coefficient, but even this quantity requires a calibration of the signals. With four years of measurements from a Jenoptik ceilometer CHM15k-x, we developed two methods for an absolute calibration on this system. This advantage of our approach is that only a few days with favorable meteorological conditions are required where Rayleigh-calibration and comparison with our research lidar is possible to estimate the lidar constant. This method enables us to derive the particle backscatter coefficient at 1064 nm, and we retrieved for the first time profiles in near real-time within an accuracy of 10 %. If an appropriate lidar ratio is assumed the <span class="hlt">aerosol</span> optical depth of e.g. the mixing <span class="hlt">layer</span> can be determined with an accuracy depending on the accuracy of the lidar ratio estimate. Even for 'simple' applications, e.g. assessment of the mixing <span class="hlt">layer</span> <span class="hlt">height</span>, cloud detection, detection of elevated <span class="hlt">aerosol</span> <span class="hlt">layers</span>, the particle backscatter coefficient has significant advantages over the measured (uncalibrated) attenuated backscatter. The possibility of continuous operation under nearly any meteorological condition with temporal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A51E0110G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A51E0110G"><span id="translatedtitle">Impact of Anthropogenic <span class="hlt">Aerosol</span> on the Properties of Shallow Maritime Cumulus Clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, L.; Wilcox, E. M.; Shan, Y.</p> <p>2015-12-01</p> <p>The northern Indian Ocean region is frequently covered by cumulus clouds that are responsible for moistening the boundary <span class="hlt">layer</span> and contribute to tropical deep convection. Because this region is uniquely located close to the highly polluted Indian plateau, air mass with high <span class="hlt">aerosol</span> concentration can be easily transported to this area. These small cumulus clouds, coupled with the effects of <span class="hlt">aerosol</span>, have a large potential to affect the regional and global albedo. The <span class="hlt">aerosol</span> effects on cloud properties and atmospheric structures are examined in this work, using the UAV (Unmanned Aerial Vehicle) data that are observed from CARDEX (Cloud, <span class="hlt">Aerosol</span>, Radiative forcing, Dynamics EXperiment) and MAC (Maldives Autonomous unmanned aerial vehicle Campaign). On average, the high polluted cases show warmer temperature through the entire atmospheric column and higher relative humidity in boundary <span class="hlt">layer</span>. The maximum temperature difference between high and low polluted cases can be found around the cloud <span class="hlt">layer</span> altitude. In addition, the <span class="hlt">height</span> of sub-cloud mixed <span class="hlt">layer</span> is higher in low polluted cases. Clouds in high polluted cases are generally becoming narrower and taller than those in low polluted cases, and are associated with greater cloud water content and higher cloud droplet number concentrations, especially in small droplet range (diameters less than 10 micrometers). Meanwhile, the effective radius of cloud droplets decreases as the <span class="hlt">aerosol</span> concentration increases. These facts indicate that the high polluted clouds are on average brighter with higher albedo.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1814245H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1814245H&link_type=ABSTRACT"><span id="translatedtitle">Numerical studies of microphysical modulations of stratospheric <span class="hlt">aerosol</span> within ROMIC-ROSA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hommel, René; von Savigny, Christian; Rozanov, Alexei; Burrows, John; Zalach, Jakob</p> <p>2016-04-01</p> <p>The stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span> (so-called Junge <span class="hlt">layer</span>) is an inherent part of the Brewer-Dobson circulation (BDC). Stratospheric <span class="hlt">aerosols</span> play a large role in the Earth's climate system because they interact with catalytic cycles depleting ozone, directly alter the atmosphere's radiative balance and modulate the strength of polar vortices, in particular when this system is perturbed. In terms of mass the <span class="hlt">layer</span> is predominantly composed of liquid sulphate-water droplets and is fed from the oxidation of gaseous precursors reaching the stratosphere either by direct volcanic injections (mainly supplying SO2) or troposphere-stratosphere exchange processes. In volcanically quiescent periods, latter processes predominantly maintain the so-called background state of <span class="hlt">aerosol</span> <span class="hlt">layer</span> through oxidation of OCS above 22 km, and SO2 below. The Junge <span class="hlt">layer</span> begins to develop 2-3 km above the tropopause and reaches a <span class="hlt">height</span> of about 35 km, with a largest vertical extent in the tropics and spring-time polar regions. Above the TTL, the <span class="hlt">layer</span>'s vertical extent varies between 2 km and 8 km (about 35% of its mean vertical expansion), depending on the phase of the QBO. The QBO-induced meridional circulation, overlying the BDC, and accompanied signatures in the stratospheric temperature directly affect the life cycle of stratospheric <span class="hlt">aerosol</span>. Mainly by modulating the equilibrium between microphysical processes which maintain the <span class="hlt">layer</span>. Effects caused by QBO modulations of the advective transport in the upwelling region of the BDC are smaller and difficult to quantify, because the overlying sedimentation of <span class="hlt">aerosol</span> is also being modulated and counteract the <span class="hlt">aerosol</span> lofting. Here we show results from numerical studies performed within the project ROMIC-ROSA (Role of Stratospheric <span class="hlt">Aerosol</span> in Climate and Atmospheric Science). We further explored relationships between QBO forcing and <span class="hlt">aerosol</span> processes in the lower stratosphere. We examined whether similar process interferences can be caused by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16955903','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16955903"><span id="translatedtitle">Single-particle detection efficiencies of <span class="hlt">aerosol</span> time-of-flight mass spectrometry during the North Atlantic marine boundary <span class="hlt">layer</span> experiment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dall'Osto, Manuel; Harrison, Roy M; Beddows, David C S; Freney, Evelyn J; Heal, Mathew R; Donovan, Robert J</p> <p>2006-08-15</p> <p>During the North Atlantic marine boundary <span class="hlt">layer</span> experiment (NAMBLEX) sampling campaign at Mace Head, Ireland, both continental and maritime air masses were sampled. <span class="hlt">Aerosol</span> was characterized both with a TSI 3800 time-of-flight mass spectrometer (ATOFMS) and a MOUDI microorifice impactor, and particle number counts were measured independently with an aerodynamic particle sizer. The data have been analyzed in order to elucidate factors determining the particle detection efficiencies of the ATOFMS. These are broken down according to the efficiency of the inlet system, the hit efficiency on particles which enter the sensing zone of the instrument and the sensitivity of the measured ion signal to the chemical species. A substantial matrix effect depending on the chemical composition of the <span class="hlt">aerosol</span> sampled at the time was found, which is reflected in variations in the hit efficiency of particles entering the sensing zone of the instrument with the main desorption-ionization laser. This is in addition to the strong inverse power-law dependence of inlet transmission efficiency on particle diameter. The variation in hit efficiency with particle type is likely attributable to differences in the energetics of laser energy absorption, ablation, and ion formation. However, once variations in both inlet transmission and hit efficiencies are taken into account, no additional matrix dependence of ATOFMS response is required to obtain a linear relationship between the ion signal and the concentration of a particular chemical species. The observations show that a constant mass of material is ionized from each particle, irrespective of size. Consequently the integrated ion signal for a given chemical component and particle size class needs to be increased by a factor related to the cube of particle diameter in order to correlate with the airborne mass of that component. PMID:16955903</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860063890&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528Ozone%2Blayer%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860063890&hterms=Ozone+layer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528Ozone%2Blayer%2529"><span id="translatedtitle">Cumulus cloud venting of mixed <span class="hlt">layer</span> ozone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ching, J. K. S.; Shipley, S. T.; Browell, E. V.; Brewer, D. A.</p> <p>1985-01-01</p> <p>Observations are presented which substantiate the hypothesis that significant vertical exchange of ozone and <span class="hlt">aerosols</span> occurs between the mixed <span class="hlt">layer</span> and the free troposphere during cumulus cloud convective activity. The experiments utilized the airborne Ultra-Violet Differential Absorption Lidar (UV-DIAL) system. This system provides simultaneous range resolved ozone concentration and <span class="hlt">aerosol</span> backscatter profiles with high spatial resolution. Evening transects were obtained in the downwind area where the air mass had been advected. Space-<span class="hlt">height</span> analyses for the evening flight show the cloud debris as patterns of ozone typically in excess of the ambient free tropospheric background. This ozone excess was approximately the value of the concentration difference between the mixed <span class="hlt">layer</span> and free troposphere determined from independent vertical soundings made by another aircraft in the afternoon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21886230','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21886230"><span id="translatedtitle"><span class="hlt">Aerosol</span> lenses propagation model.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tremblay, Grégoire; Roy, Gilles</p> <p>2011-09-01</p> <p>We propose a model based on the properties of cascading lenses modulation transfer function (MTF) to reproduce the irradiance of a screen illuminated through a dense <span class="hlt">aerosol</span> cloud. In this model, the <span class="hlt">aerosol</span> cloud is broken into multiple thin <span class="hlt">layers</span> considered as individual lenses. The screen irradiance generated by these individual <span class="hlt">layers</span> is equivalent to the point-spread function (PSF) of each <span class="hlt">aerosol</span> lens. Taking the Fourier transform of the PSF as a MTF, we cascade the lenses MTF to find the cloud MTF. The screen irradiance is found with the Fourier transform of this MTF. We show the derivation of the model and we compare the results with the Undique Monte Carlo simulator for four <span class="hlt">aerosols</span> at three optical depths. The model is in agreement with the Monte Carlo for all the cases tested. PMID:21886230</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/802874','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/802874"><span id="translatedtitle">Comparison of <span class="hlt">Aerosol</span> Properties within and above the ABL at the ARM Program's SGP Site</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Monache, L.D.; Perry, K.D.; Cederwall, R.T.</p> <p>2002-02-26</p> <p>The goal of this study was to determine under what conditions, if any, measurements of <span class="hlt">aerosol</span> properties made at the Earth's surface are representative of the <span class="hlt">aerosol</span> properties within the column of air above the surface. This project used data from the Atmospheric Radiation Measurement (ARM) site at the Southern Great Plains (SGP) site (Stokes and Schwartz 1994), which is one of the only locations in the world where ground-based and in situ airborne measurements of atmospheric <span class="hlt">aerosol</span> are made on a routine basis. All flight legs in the one-year period from March 2000 to March 2001 were categorized as either within or above the atmospheric boundary <span class="hlt">layer</span> (ABL) using an objective mixing <span class="hlt">height</span> determination technique. The correlations between the <span class="hlt">aerosol</span> properties measured at the surface and those measured within and above the ABL were then computed. The conclusion of this comparison is that the <span class="hlt">aerosol</span> extensive properties (those that depend upon the amount of <span class="hlt">aerosol</span> that is present in the atmosphere, i.e., either the number or mass concentrations), and intensive properties (those that do not depend upon the amount of <span class="hlt">aerosol</span> present) measured at the surface are representative of values within the ABL, but not within the free atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000PhDT........19Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000PhDT........19Y"><span id="translatedtitle">Radiative effects of <span class="hlt">aerosols</span> on the environment in China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Hongbin</p> <p></p> <p>Anthropogenic emissions and concentrations of <span class="hlt">aerosol</span> precursors and <span class="hlt">aerosols</span> over China are among the highest in major countries of the world. Due to large emissions of soot and dust, <span class="hlt">aerosol</span> absorption is high. Based on the observed direct and diffuse irradiance, a single scattering albedo of about 0.8 is derived for two large agri/eco/industrial areas. <span class="hlt">Aerosol</span> direct effect can exert various environmental impacts in China. Photochemical activities in the atmospheric boundary <span class="hlt">layer</span> (ABL) are significantly reduced because of reductions in photolysis rates and in emissions of biogenic hydrocarbons. Crop yields under optimal conditions can be reduced due to the reduction in surface solar irradiance. The most significant <span class="hlt">aerosol</span> radiative perturbation is in changing the air-surface interaction and diurnal evolution of ABL. Reductions in various surface heat fluxes due to <span class="hlt">aerosols</span> depend on soil moisture. Over a relatively dry surface, the evaporation has a small change, leading to the largest decrease of surface skin temperature at noon. Over a relatively wet surface, a substantial reduction in evaporation results in the largest surface cooling in the early morning. The diurnal temperature range (DTR) can be reduced by an amount comparable to the observed decrease of DTR. The longwave absorption of <span class="hlt">aerosols</span> can lead to an increase of the daily minimum temperature and contributes to about 20% of the decrease in the DTR. The near-surface air temperature has the largest cooling in the early morning because the ABL is shallow and the temperature is sensitive to the radiative perturbation. As a result of the reduced sensible heat flux, the surface <span class="hlt">layer</span> becomes more stable. Moreover, the <span class="hlt">aerosol</span> heating enhances the stabilization of surface <span class="hlt">layer</span> and in turn further reduces the sensible heat flux. As a result the ABL <span class="hlt">height</span> can be reduced substantially. This will have many important ramifications, including trapping/accumulation of air pollutants, and perturbing the water</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995JApMe..34.1802M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995JApMe..34.1802M"><span id="translatedtitle">Comparison of Methods for Estimating Mixing <span class="hlt">Height</span> Used during the 1992 Atlanta Field Intensive.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marsik, Frank J.; Fischer, Kenneth W.; McDonald, Tracey D.; Samson, Perry J.</p> <p>1995-08-01</p> <p>During the summer of 1992, measurements of the boundary <span class="hlt">layer</span> mixing <span class="hlt">height</span> were conducted at five locations around the city of Atlanta, Georgia, as part of the 1992 Atlanta Field Intensive of the Southern Oxidants Research Program on Ozone Non-Attainment. These measurements were made during a series of `high-ozone-event days' for the purpose of acquiring information about the temporal evolution of the convective mixed <span class="hlt">layer</span>. The information acquired from these systems was included in a database of meteorological variables for use in the photochemical modeling efforts associated with the study. The following measurement systems were selected for use in this study by organizers of the 1992 Atlanta Field Intensive: one rawinsonde system, four radar wind profiler RASS (radar acoustic sounding system) systems, and two lidar systems.A comparison of the mixing-<span class="hlt">height</span> estimates from each of the measurement systems used during the 1992 Atlanta Field Intensive was performed in an effort to evaluate the consistency of the estimates between the different systems and, further, to evaluate the relative performance of each system during the study period. Statistical analyses were performed on the dataset, with in-depth statistical analyses presented for two specific days: 30 July and 4 August 1992. Results indicate that there is often disagreement in the mixing-<span class="hlt">height</span> estimates between the various systems, particularly during the early morning and late afternoon. It is believed that the differences between estimates are the result of 1) the physical limitations of the different instrument system 2) the assumptions used with each system as to which tracer most accurately defines the structure of the convective boundary <span class="hlt">layer</span>, and 3) the spatial inhomogeneity of convective boundary <span class="hlt">layer</span> structure across the region studied.In general, the rawinsonde system appeared to give the most accurate mixing-<span class="hlt">height</span> estimates under the meteorological conditions studied. The lidar estimates</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A24B..01H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A24B..01H"><span id="translatedtitle">Relating <span class="hlt">Aerosol</span> Profile and Column Measurements to Surface Concentrations: What Have We Learned from Discover-AQ?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoff, R. M.</p> <p>2014-12-01</p> <p>One research goal of the Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) mission was to determine sufficient column profile measurements to relate column integrated quantities such as <span class="hlt">Aerosol</span> Optical Depth to surface concentrations. I will review the relationship between AOD and PM2.5 at the surface. DISCOVER-AQ in Baltimore, the San Joaquin Valley, Houston and Denver revealed quite different conditions for determining this relationship. In each case, the surface reflectivity made determination of <span class="hlt">aerosol</span> optical depth challenging, but upward looking columns of <span class="hlt">aerosol</span> optical depth from sunphotometers provided confirmation of the AOD results from space. In Baltimore, AOD fields reflected PM2.5 concentrations well. In California, however, the low boundary <span class="hlt">layer</span> <span class="hlt">heights</span> and dominance of nitrate and organic <span class="hlt">aerosols</span> made the AOD fields less predictive of PM2.5. In California and Colorado, hydration of the <span class="hlt">aerosol</span> varied dramatically with <span class="hlt">aerosol</span> type (especially smoke and dust) and revealed that without an understanding of the degree of <span class="hlt">aerosol</span> hydration with <span class="hlt">aerosol</span> composition, the relationship between AOD and PM2.5 will continue to be a challenge. Model predictions in the Baltimore-Washington study are relatively disappointing in helping define the needed physics between the optical and microphysical properties. An overview of the measurements from DISCOVER-AQ which will help define the needed information in a more general case in the future will be given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015BoLMe.155..329P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015BoLMe.155..329P&link_type=ABSTRACT"><span id="translatedtitle">A Model for the Transport of Sea-Spray <span class="hlt">Aerosols</span> in the Coastal Zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piazzola, J.; Tedeschi, G.; Demoisson, A.</p> <p>2015-05-01</p> <p>We study the dynamics of sea-spray particles in the coastal region of La Reunion Island on the basis of numerical simulations using the transport <span class="hlt">aerosol</span> model MACMod (Marine <span class="hlt">Aerosol</span> Concentration Model) and a survey of the <span class="hlt">aerosol</span> size distributions measured at four locations at two different <span class="hlt">heights</span> in the north-west part of the island. This allows evaluation of the performance of our model in case of pure marine air masses with implementation of accurate boundary conditions. First of all, an estimate of the <span class="hlt">aerosol</span> concentration at 10-m <span class="hlt">height</span> at the upwind boundary of the calculation domain is obtained using a revisited version of the MEDEX (Mediterranean Extinction) model. Estimates of the vertical profile of <span class="hlt">aerosol</span> concentrations are then provided using <span class="hlt">aerosol</span> data obtained at two different <span class="hlt">heights</span> at the upwind boundary of the calculation domain. A parametrization of the vertical profiles of <span class="hlt">aerosol</span> concentrations for maritime environment is proposed. The results are then compared to the vertical profiles of 0.532 m <span class="hlt">aerosol</span> particle extinction coefficient obtained from lidar data provided by the Cloud-<span class="hlt">Aerosol</span> LIdar with Orthogonal Polarization (CALIOP) and also to the data provided by the <span class="hlt">Aerosol</span> Robotic Network (AERONET). This allows validation of the complete vertical profiles in the mixed <span class="hlt">layer</span> and shows the validity of satellite data for determination of the vertical profiles. Two kinds of simulation were made: one without a particle advection flux at the upwind boundary of the numerical domain, whereas the second simulation was made with a particle advection flux. In the first case, the influence of the distance to the shoreline on the local sea-spray dynamics is investigated. In the second set of simulation, the particles issued from the local production in the surf zone near the shoreline are mixed with <span class="hlt">aerosols</span> advected from the remote ocean. A good agreement between the model calculations using our boundary conditions and the data was found. The</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..1613302T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..1613302T&link_type=ABSTRACT"><span id="translatedtitle">Particle concentrations and number size distributions in the planetary boundary <span class="hlt">layer</span> derived from airship based measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tillmann, Ralf; Zhao, Defeng; Ehn, Mikael; Hofzumahaus, Andreas; Holland, Frank; Rohrer, Franz; Kiendler-Scharr, Astrid; Wahner, Andreas</p> <p>2014-05-01</p> <p>Atmospheric particles play a key role for regional and global climate due to their direct and indirect radiative forcing effects. The concentration and size of the particles are important variables to these effects. Within the continental planetary boundary <span class="hlt">layer</span> (PBL) the particle number size distribution is influenced by meteorological parameters, local sinks and sources resulting in variable spatial distributions. However, measurements of particle number size distributions over a broad vertical range of the PBL are rare. The airship ZEPPELIN NT is an ideal platform to measure atmospheric <span class="hlt">aerosols</span> on a regional scale within an altitude range up to 1000 m. For campaigns in the Netherlands, Northern Italy and South Finland in 2012 and 2013 the airship was deployed with a wide range of instruments, including measurements of different trace gases, short lived radicals, solar radiation, <span class="hlt">aerosols</span> and meteorological parameters. Flights were carried out at different times of the day to investigate the influence of the diurnal evolution of the PBL on atmospheric trace gases and <span class="hlt">aerosols</span>. During night and early morning hours the concentration and size distribution of atmospheric particles were found to be strongly influenced by the <span class="hlt">layered</span> structure of the PBL, i.e. the nocturnal boundary <span class="hlt">layer</span> and the residual <span class="hlt">layer</span>. Within the residual <span class="hlt">layer</span> particle concentrations stay relatively constant as this <span class="hlt">layer</span> is decoupled from ground sources. The particles persist in the accumulation mode as expected for an aged <span class="hlt">aerosol</span>. In the nocturnal boundary <span class="hlt">layer</span> particle concentrations and size are more dynamic with higher concentrations than in the residual <span class="hlt">layer</span>. A few hours after sunrise, the <span class="hlt">layered</span> structure of the PBL intermixes. During daytime the PBL is well mixed and a negative concentration gradient with increasing <span class="hlt">height</span> is observed. Several <span class="hlt">height</span> profiles at different times of the day and at different locations in Europe were measured. The <span class="hlt">aerosol</span> measurements will be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ACP....16.9201W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ACP....16.9201W"><span id="translatedtitle">The importance of plume rise on the concentrations and atmospheric impacts of biomass burning <span class="hlt">aerosol</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Walter, Carolin; Freitas, Saulo R.; Kottmeier, Christoph; Kraut, Isabel; Rieger, Daniel; Vogel, Heike; Vogel, Bernhard</p> <p>2016-07-01</p> <p>We quantified the effects of the plume rise of biomass burning <span class="hlt">aerosol</span> and gases for the forest fires that occurred in Saskatchewan, Canada, in July 2010. For this purpose, simulations with different assumptions regarding the plume rise and the vertical distribution of the emissions were conducted. Based on comparisons with observations, applying a one-dimensional plume rise model to predict the injection <span class="hlt">layer</span> in combination with a parametrization of the vertical distribution of the emissions outperforms approaches in which the plume <span class="hlt">heights</span> are initially predefined. Approximately 30 % of the fires exceed the <span class="hlt">height</span> of 2 km with a maximum <span class="hlt">height</span> of 8.6 km. Using this plume rise model, comparisons with satellite images in the visible spectral range show a very good agreement between the simulated and observed spatial distributions of the biomass burning plume. The simulated <span class="hlt">aerosol</span> optical depth (AOD) with data of an AERONET station is in good agreement with respect to the absolute values and the timing of the maximum. Comparison of the vertical distribution of the biomass burning <span class="hlt">aerosol</span> with CALIPSO (Cloud-<span class="hlt">Aerosol</span> Lidar and Infrared Pathfinder Satellite Observation) retrievals also showed the best agreement when the plume rise model was applied. We found that downwelling surface short-wave radiation below the forest fire plume is reduced by up to 50 % and that the 2 m temperature is decreased by up to 6 K. In addition, we simulated a strong change in atmospheric stability within the biomass burning plume.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020064465&hterms=air+pollution+hawaii&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dair%2Bpollution%2Bhawaii','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020064465&hterms=air+pollution+hawaii&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dair%2Bpollution%2Bhawaii"><span id="translatedtitle">Overview of ACE-Asia Spring 2001 Investigations On <span class="hlt">Aerosol</span>-Radiation Interactions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Russell, P. B.; Flatau, P. J.; Valero, F. P. J.; Nakajima, T.; Holben, B.; Pilewskie, P.; Bergin, M.; Schmid, B.; Bergstrom, R. W.; Vogelmann, A.; Hipskind, R. Stephen (Technical Monitor)</p> <p>2002-01-01</p> <p>ACE-Asia's extensive measurements from land, ocean, air and space quantified <span class="hlt">aerosol</span>-radiation interactions. Results from each platform type, plus satellite-suborbital combinations, include: 1. Time series of multiwavelength <span class="hlt">aerosol</span> optical depth (ADD), Angstrom exponent (alpha), single-scattering albedo (SSA), and size distribution from AERONET radiometry at 13 stations. In China and Korea AOD and alpha were strongly anticorrelated (reflecting transient dust events); dust volume-size modes peaked near 8 microns diameter; and SSA(dust) greater than SSA(pollution). 2. Calculations and measurements of photosynthetically active radiation and <span class="hlt">aerosols</span> in China yield 24-h average downward surface radiative forcing per AOD(500 nm) of -27 W/sq m (400-700 nm). 3. The Hawaii-Japan cruise sampled a gradient with AOD(500 nm) extremes of 0.1 and 1.1. Shipboard measurements showed that adding dust to pollution increased SSA(550 nm, 55% RH), typically from -0.91 to approx. 0.97. Downwelling 8-12 micron radiances showed <span class="hlt">aerosol</span> effects, especially in the major April dust event, with longwave forcing estimated at -5 to 15 W/sq m. 4. Extinction profiles from airborne sunphotometry and total-direct-diffuse radiometry show wavelength dependence often varying strongly with <span class="hlt">height</span>, reflecting <span class="hlt">layering</span> of dust-dominated over pollution-dominated <span class="hlt">aerosols</span>. Comparing sunphotometric extinction profiles to those from in situ measurements (number and composition vs size, or scattering and absorption) shows <span class="hlt">layer</span> <span class="hlt">heights</span> agree, but extinction sometimes differs. 5. Airborne solar spectral flux radiometry yields absorption spectra for <span class="hlt">layers</span>. Combining with AOD spectra yields best-fit <span class="hlt">aerosol</span> single scattering albedo spectra. 6. Visible, NIR and total solar fluxes combined with AOD give radiative forcing efficiencies at surface and aloft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1203..346I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1203..346I"><span id="translatedtitle">Radioactive <span class="hlt">Aerosols</span> as an Index of Air Pollution in the City of Thessaloniki, Greece</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ioannidou, A.; Papastefanou, C.</p> <p>2010-01-01</p> <p>This study summarizes results of an investigation done in order to find out how the radioactive <span class="hlt">aerosols</span> of 7Be could serve as indicators of air pollution conditions. Beryllium-7 is a cosmic-ray produced radionuclide with an important fraction of its production to take place in the upper troposphere. Once it is formed is rapidly associated with submicron <span class="hlt">aerosol</span> particles and participates in the formation and growth of the accumulation mode <span class="hlt">aerosols</span>, which is a major reservoir of pollutants in the atmosphere. In order to define any influence of AMAD of 7Be <span class="hlt">aerosols</span> by air pollution conditions, the aerodynamic size distribution of 7Be <span class="hlt">aerosols</span> was determined by collecting samples at different locations in the suburban area of the city of Thessaloniki, including rural areas, industrial areas, high elevations, marine environment and the airport area. The aerodynamic size distribution of 7Be <span class="hlt">aerosols</span> in different locations was obtained by using Andersen 1-ACFM cascade impactors and the Activity Median Aerodynamic Diameter (AMAD) was determined. Some dependency of the AMADs on <span class="hlt">height</span> has been observed, while in near marine environment the 7Be activity size distribution was dominant in the upper size range of <span class="hlt">aerosol</span> particles. Low AMADs as low as 0.62 to 0.74 μm of 7Be <span class="hlt">aerosols</span> have been observed at locations characterized with relative low pollution, while it is concluded that in the activity size distribution of ambient <span class="hlt">aerosols</span>, 7Be changes to larger particle sizes in the presence of pollutants, since low AMADs of 7Be <span class="hlt">aerosols</span> have been observed at low polluted locations. Preliminary data of simultaneous measurements of 214Pb and 212Pb with gaseous air pollutants CO, NO, NOX, SO2 and total suspended particulate matter (TSP) show that radon decay products near the ground could be a useful index of air pollution potential conditions and transport processes in the boundary <span class="hlt">layer</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1948943','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1948943"><span id="translatedtitle"><span class="hlt">Height</span>, health, and development</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Deaton, Angus</p> <p>2007-01-01</p> <p>Adult <span class="hlt">height</span> is determined by genetic potential and by net nutrition, the balance between food intake and the demands on it, including the demands of disease, most importantly during early childhood. Historians have made effective use of recorded <span class="hlt">heights</span> to indicate living standards, in both health and income, for periods where there are few other data. Understanding the determinants of <span class="hlt">height</span> is also important for understanding health; taller people earn more on average, do better on cognitive tests, and live longer. This paper investigates the environmental determinants of <span class="hlt">height</span> across 43 developing countries. Unlike in rich countries, where adult <span class="hlt">height</span> is well predicted by mortality in infancy, there is no consistent relationship across and within countries between adult <span class="hlt">height</span> on the one hand and childhood mortality or living conditions on the other. In particular, adult African women are taller than is warranted by their low incomes and high childhood mortality, not to mention their mothers' educational level and reported nutrition. High childhood mortality in Africa is associated with taller adults, which suggests that mortality selection dominates scarring, the opposite of what is found in the rest of the world. The relationship between population <span class="hlt">heights</span> and income is inconsistent and unreliable, as is the relationship between income and health more generally. PMID:17686991</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22395578','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22395578"><span id="translatedtitle">Atomic <span class="hlt">layer</span> epitaxy of Ruddlesden-Popper SrO(SrTiO{sub 3}){sub n} films by means of metalorganic <span class="hlt">aerosol</span> deposition</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jungbauer, M.; Hühn, S.; Moshnyaga, V.; Egoavil, R.; Tan, H.; Verbeeck, J.; Van Tendeloo, G.</p> <p>2014-12-22</p> <p>We report an atomic <span class="hlt">layer</span> epitaxial growth of Ruddlesden-Popper (RP) thin films of SrO(SrTiO{sub 3}){sub n} (n = ∞, 2, 3, 4) by means of metalorganic <span class="hlt">aerosol</span> deposition (MAD). The films are grown on SrTiO{sub 3}(001) substrates by means of a sequential deposition of Sr-O/Ti-O{sub 2} atomic monolayers, monitored in-situ by optical ellipsometry. X-ray diffraction and transmission electron microscopy (TEM) reveal the RP structure with n = 2–4 in accordance with the growth recipe. RP defects, observed by TEM in a good correlation with the in-situ ellipsometry, mainly result from the excess of SrO. Being maximal at the film/substrate interface, the SrO excess rapidly decreases and saturates after 5–6 repetitions of the SrO(SrTiO{sub 3}){sub 4} block at the level of 2.4%. This identifies the SrTiO{sub 3} substrate surface as a source of RP defects under oxidizing conditions within MAD. Advantages and limitations of MAD as a solution-based and vacuum-free chemical deposition route were discussed in comparison with molecular beam epitaxy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1169501','SCIGOV-DOEDE'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1169501"><span id="translatedtitle">Raman lidar/AERI PBL <span class="hlt">Height</span> Product</span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Ferrare, Richard</p> <p>2012-12-14</p> <p>Planetary Boundary <span class="hlt">Layer</span> (PBL) <span class="hlt">heights</span> have been computed using potential temperature profiles derived from Raman lidar and AERI measurements. Raman lidar measurements of the rotational Raman scattering from nitrogen and oxygen are used to derive vertical profiles of potential temperature. AERI measurements of downwelling radiance are used in a physical retrieval approach (Smith et al. 1999, Feltz et al. 1998) to derive profiles of temperature and water vapor. The Raman lidar and AERI potential temperature profiles are merged to create a single potential temperature profile for computing PBL <span class="hlt">heights</span>. PBL <span class="hlt">heights</span> were derived from these merged potential temperature profiles using a modified Heffter (1980) technique that was tailored to the SGP site (Della Monache et al., 2004). PBL <span class="hlt">heights</span> were computed on an hourly basis for the period January 1, 2009 through December 31, 2011. These <span class="hlt">heights</span> are provided as meters above ground level.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013Ocgy...53..727L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Ocgy...53..727L"><span id="translatedtitle">Chemical composition of <span class="hlt">aerosols</span> in the near-water surface atmospheric <span class="hlt">layer</span> of the central Caspian Sea in the winter and autumn of 2005</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lukashin, V. N.; Novigatsky, A. N.</p> <p>2013-11-01</p> <p>The chemical composition (43 elements) of <span class="hlt">aerosols</span> is reviewed for the Caspian Sea based on nine samples taken in the winter and autumn of 2005. The <span class="hlt">aerosols</span> are considered as geological material incoming to the sea from the atmosphere. The major <span class="hlt">aerosol</span> components are distinguished and the degree of the concentration is calculated for a series of trace elements relative to their contents in the lithosphere. Se, Cd, Sb, Au, and Pb are concentrated by one-two orders of magnitude, which is related to the pollution. A correlation matrix is given for the studied elements, and their relations with the major components of the <span class="hlt">aerosols</span> are revealed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A13I3292M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A13I3292M"><span id="translatedtitle">Measurements of the HO2 uptake coefficient onto aqueous salt and organic <span class="hlt">aerosols</span> and interpretation using the kinetic multi-<span class="hlt">layer</span> model of <span class="hlt">aerosol</span> surface and bulk chemistry (KM-SUB)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matthews, P. S. J.; Berkemeier, T.; George, I. J.; Whalley, L. K.; Moon, D. R.; Ammann, M.; Baeza-Romero, M. T.; Poeschl, U.; Shiraiwa, M.; Heard, D. E.</p> <p>2014-12-01</p> <p>HO2 is closely coupled with OH which is responsible for the majority of the oxidation in the troposphere. Therefore, it is important to be able to accurately predict OH and HO2 concentrations. However, many studies have reported a large discrepancy between HO2 radical concentrations measured during field campaigns and predicted by constrained box models using detailed chemical mechanisms (1,2). However, there have been very few laboratory studies (3,4) on HO2 uptake by <span class="hlt">aerosols</span> and the rates and mechanism is still uncertain. The HO2 uptake coefficients were measured for deliquesced ammonium nitrate and sodium chloride <span class="hlt">aerosols</span> and copper doped sucrose <span class="hlt">aerosols</span>. The measurements were performed using an <span class="hlt">aerosol</span> flow tube coupled to a Fluorescence Assay by Gas Expansion (FAGE) detector. By either placing the HO2 injector in set positions and varying the <span class="hlt">aerosol</span> concentration or by moving it along the flow tube at given <span class="hlt">aerosol</span> concentrations, uptake coefficients could be measured. The <span class="hlt">aerosols</span> were generated using an atomiser and the total <span class="hlt">aerosol</span> surface area was measured using a SMPS. Larger uptake coefficients were measured at shorter times and lower HO2 concentrations for aqueous salt <span class="hlt">aerosols</span>. The time dependence was able to be modelled by the KM-SUB model (5) as the HO2 concentration decreases along the flow tube and the HO2 uptake mechanism is known to be a second order reaction. Measurements have shown that at higher HO2 concentrations there was also more H2O2 exiting the injector which could convert back to HO2 if trace amounts of metals are present within the <span class="hlt">aerosol</span> via Fenton reactions. Preliminary results have shown that the inclusion of a Fenton-like reaction within the KM-SUB model has the potential to explain the apparent HO2 concentration dependence. Finally, the KM-SUB model has been used to demonstrate that the increase in uptake coefficient observed when increasing the relative humidity for copper doped sucrose <span class="hlt">aerosols</span> could be explained by an</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006ACPD....6..401H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006ACPD....6..401H"><span id="translatedtitle"><span class="hlt">Aerosol</span> chemical and optical properties over the Paris area within ESQUIF project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hodzic, A.; Vautard, R.; Chazette, P.; Menut, L.; Bessagnet, B.</p> <p>2006-01-01</p> <p><span class="hlt">Aerosol</span> chemical and optical properties are extensively investigated for the first time over the Paris Basin in July 2000 within the ESQUIF project. The measurement campaign offers an exceptional framework to evaluate the performances of the chemistry-transport model CHIMERE in simulating concentrations of gaseous and <span class="hlt">aerosol</span> pollutants, as well as the <span class="hlt">aerosol</span>-size distribution and composition in polluted urban environment against ground-based and airborne measurements. A detailed comparison of measured and simulated variables during the second half of July with particular focus on 19 and 31 pollution episodes reveals an overall good agreement for gas-species and <span class="hlt">aerosol</span> components both at the ground level and along flight trajectories, and the absence of systematic biases in simulated meteorological variables such as wind speed, relative humidity and boundary <span class="hlt">layer</span> <span class="hlt">height</span> as computed by the MM5 model. A good consistency in ozone and NO concentrations demonstrates the ability of the model to reproduce fairly well the plume structure and location both on 19 and 31 July, despite an underestimation of the amplitude of ozone concentrations on 31 July. The spatial and vertical <span class="hlt">aerosol</span> distributions are also examined by comparing simulated and observed lidar vertical profiles along flight trajectories on 31 July and confirmed the model capacity to simulate the plume characteristics. The comparison of observed and modeled <span class="hlt">aerosol</span> components in the southwest suburb of Paris during the second half of July indicated that the <span class="hlt">aerosol</span> composition is rather correctly reproduced, although the total <span class="hlt">aerosol</span> mass is underestimated of about 20%. The simulated Parisian <span class="hlt">aerosol</span> is dominated by primary particulate matter that accounts for anthropogenic and biogenic primary particles (40%) and inorganic <span class="hlt">aerosol</span> fraction (40%) including nitrate (8%), sulfate (22%) and ammonium (10%). The secondary organic <span class="hlt">aerosols</span> (SOA) represent 12% of the total <span class="hlt">aerosol</span> mass, while the mineral dust</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006ACP.....6.3257H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006ACP.....6.3257H"><span id="translatedtitle"><span class="hlt">Aerosol</span> chemical and optical properties over the Paris area within ESQUIF project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hodzic, A.; Vautard, R.; Chazette, P.; Menut, L.; Bessagnet, B.</p> <p>2006-08-01</p> <p><span class="hlt">Aerosol</span> chemical and optical properties are extensively investigated for the first time over the Paris Basin in July 2000 within the ESQUIF project. The measurement campaign offers an exceptional framework to evaluate the performances of the chemistry-transport model CHIMERE in simulating concentrations of gaseous and <span class="hlt">aerosol</span> pollutants, as well as the <span class="hlt">aerosol</span>-size distribution and composition in polluted urban environments against ground-based and airborne measurements. A detailed comparison of measured and simulated variables during the second half of July with particular focus on 19 and 31 pollution episodes reveals an overall good agreement for gas-species and <span class="hlt">aerosol</span> components both at the ground level and along flight trajectories, and the absence of systematic biases in simulated meteorological variables such as wind speed, relative humidity and boundary <span class="hlt">layer</span> <span class="hlt">height</span> as computed by the MM5 model. A good consistency in ozone and NO concentrations demonstrates the ability of the model to reproduce the plume structure and location fairly well both on 19 and 31 July, despite an underestimation of the amplitude of ozone concentrations on 31 July. The spatial and vertical <span class="hlt">aerosol</span> distributions are also examined by comparing simulated and observed lidar vertical profiles along flight trajectories on 31 July and confirm the model capacity to simulate the plume characteristics. The comparison of observed and modeled <span class="hlt">aerosol</span> components in the southwest suburb of Paris during the second half of July indicates that the <span class="hlt">aerosol</span> composition is rather correctly reproduced, although the total <span class="hlt">aerosol</span> mass is underestimated by about 20%. The simulated Parisian <span class="hlt">aerosol</span> is dominated by primary particulate matter that accounts for anthropogenic and biogenic primary particles (40%), and inorganic <span class="hlt">aerosol</span> fraction (40%) including nitrate (8%), sulfate (22%) and ammonium (10%). The secondary organic <span class="hlt">aerosols</span> (SOA) represent 12% of the total <span class="hlt">aerosol</span> mass, while the mineral dust</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AMT.....9.1181C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AMT.....9.1181C"><span id="translatedtitle">Lidar-Radiometer Inversion Code (LIRIC) for the retrieval of vertical <span class="hlt">aerosol</span> properties from combined lidar/radiometer data: development and distribution in EARLINET</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chaikovsky, Anatoli; Dubovik, Oleg; Holben, Brent; Bril, Andrey; Goloub, Philippe; Tanré, Didier; Pappalardo, Gelsomina; Wandinger, Ulla; Chaikovskaya, Ludmila; Denisov, Sergey; Grudo, Jan; Lopatin, Anton; Karol, Yana; Lapyonok, Tatsiana; Amiridis, Vassilis; Ansmann, Albert; Apituley, Arnoud; Allados-Arboledas, Lucas; Binietoglou, Ioannis; Boselli, Antonella; D'Amico, Giuseppe; Freudenthaler, Volker; Giles, David; José Granados-Muñoz, María; Kokkalis, Panayotis; Nicolae, Doina; Oshchepkov, Sergey; Papayannis, Alex; Perrone, Maria Rita; Pietruczuk, Alexander; Rocadenbosch, Francesc; Sicard, Michaël; Slutsker, Ilya; Talianu, Camelia; De Tomasi, Ferdinando; Tsekeri, Alexandra; Wagner, Janet; Wang, Xuan</p> <p>2016-03-01</p> <p>This paper presents a detailed description of LIRIC (LIdar-Radiometer Inversion Code) algorithm for simultaneous processing of coincident lidar and radiometric (sun photometric) observations for the retrieval of the <span class="hlt">aerosol</span> concentration vertical profiles. As the lidar/radiometric input data we use measurements from European <span class="hlt">Aerosol</span> Research Lidar Network (EARLINET) lidars and collocated sun-photometers of <span class="hlt">Aerosol</span> Robotic Network (AERONET). The LIRIC data processing provides sequential inversion of the combined lidar and radiometric data. The algorithm starts with the estimations of column-integrated <span class="hlt">aerosol</span> parameters from radiometric measurements followed by the retrieval of <span class="hlt">height</span> dependent concentrations of fine and coarse <span class="hlt">aerosols</span> from lidar signals using integrated column characteristics of <span class="hlt">aerosol</span> <span class="hlt">layer</span> as a priori constraints. The use of polarized lidar observations allows us to discriminate between spherical and non-spherical particles of the coarse <span class="hlt">aerosol</span> mode.The LIRIC software package was implemented and tested at a number of EARLINET stations. Intercomparison of the LIRIC-based <span class="hlt">aerosol</span> retrievals was performed for the observations by seven EARLINET lidars in Leipzig, Germany on 25 May 2009. We found close agreement between the <span class="hlt">aerosol</span> parameters derived from different lidars that supports high robustness of the LIRIC algorithm. The sensitivity of the retrieval results to the possible reduction of the available observation data is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACP....1512413S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACP....1512413S"><span id="translatedtitle">On measurements of <span class="hlt">aerosol</span>-gas composition of the atmosphere during two expeditions in 2013 along the Northern Sea Route</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sakerin, S. M.; Bobrikov, A. A.; Bukin, O. A.; Golobokova, L. P.; Pol'kin, Vas. V.; Pol'kin, Vik. V.; Shmirko, K. A.; Kabanov, D. M.; Khodzher, T. V.; Onischuk, N. A.; Pavlov, A. N.; Potemkin, V. L.; Radionov, V. F.</p> <p>2015-11-01</p> <p>We presented the results of expedition measurements of the set of physical-chemical characteristics of atmospheric <span class="hlt">aerosol</span> in areas of the Arctic and Far East seas, performed onboard RV Akademik Fedorov (17 August-22 September 2013) and RV Professor Khljustin (24 July-7 September 2013). The specific features of spatial distribution and time variations of <span class="hlt">aerosol</span> optical depth (AOD) of the atmosphere in the wavelength range of 0.34-2.14 μm and boundary <span class="hlt">layer</span> <span class="hlt">height</span>, <span class="hlt">aerosol</span> and black carbon mass concentrations, and disperse and chemical composition of <span class="hlt">aerosol</span> are discussed. Over the Arctic Ocean (on the route of RV Akademik Fedorov) there is a decrease in <span class="hlt">aerosol</span> and black carbon concentrations in a northeastern direction: higher values were observed in the region of Spitsbergen and near the Kola Peninsula; and minimum values were observed at northern margins of the Laptev Sea. Average AOD (0.5 μm) values in this remote region were 0.03; the <span class="hlt">aerosol</span> and black carbon mass concentrations were 875 and 22 ng m-3, respectively. The spatial distributions of most <span class="hlt">aerosol</span> characteristics over Far East seas show their latitudinal decrease in the northern direction. On transit of RV Professor Khljustin from the Japan Sea to the Chukchi Sea, the <span class="hlt">aerosol</span> number concentration decreased on average from 23.7 to 2.5 cm-3, the black carbon mass concentration decreased from 150 to 50 ng m-3, and AOD decreased from 0.19 to 0.03. We analyzed the variations in the boundary <span class="hlt">layer</span> <span class="hlt">height</span>, measured by ship-based lidar: the average value was 520 m, and the maximal value was 1200 m. In latitudinal distribution of the boundary <span class="hlt">layer</span> <span class="hlt">height</span>, there is a characteristic minimum at a latitude of ~ 55° N. For water basins of eight seas, we present the chemical compositions of the water-soluble <span class="hlt">aerosol</span> fraction (ions, elements) and small gas-phase species, as well as estimates of their vertical fluxes. It is shown that substances are mainly (75-89 %) supplied from the atmosphere to the sea</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ACPD...1516775S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ACPD...1516775S"><span id="translatedtitle">On measurements of <span class="hlt">aerosol</span>-gas composition of the atmosphere during two expeditions in 2013 along Northern Sea Route</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sakerin, S. M.; Bobrikov, A. A.; Bukin, O. A.; Golobokova, L. P.; Pol'kin, Vas. V.; Pol'kin, Vik. V.; Shmirko, K. A.; Kabanov, D. M.; Khodzher, T. V.; Pavlov, A. N.; Potemkin, V. L.; Radionov, V. F.</p> <p>2015-06-01</p> <p>We presented the results of expedition measurements of the set of physical-chemical characteristics of atmospheric <span class="hlt">aerosol</span> in water basins of Arctic and Far East seas, performed onboard RV Akademik Fedorov (17 August-22 September 2013) and RV Professor Khljustin (24 July-7 September 2013). The specific features of spatial distribution and time variations of <span class="hlt">aerosol</span> optical depth (AOD) of the atmosphere in the wavelength range of 0.34-2.14 μm and boundary <span class="hlt">layer</span> <span class="hlt">height</span>, <span class="hlt">aerosol</span> and black carbon mass concentrations, and disperse and chemical composition of <span class="hlt">aerosol</span> are discussed. Over the Arctic Ocean (on the route of RV Akademik Fedorov) there is a decrease in <span class="hlt">aerosol</span> and black carbon concentrations in northeastern direction: higher values were observed in the region of Spitsbergen and near the Kola Peninsula; and minimum values were observed at northern margins of the Laptev Sea. Average AOD (0.5 μm) values in this remote region were 0.03; the <span class="hlt">aerosol</span> and black carbon mass concentrations were 875 and 22 ng m-3, respectively. The spatial distributions of most <span class="hlt">aerosol</span> characteristics over Far East seas show their latitudinal decrease in the northern direction. On transit of RV Professor Khljustin from Japan to Chukchi Sea, the <span class="hlt">aerosol</span> number concentration decreased, on the average, from 23.7 to 2.5 cm-3, the black carbon mass concentration decreased from 150 to 50 ng m-3, and AOD decreased from 0.19 to 0.03. We analyzed the variations in the boundary <span class="hlt">layer</span> <span class="hlt">height</span>, measured by ship-based lidar: the average value was 520 m, and the maximal value was 1200 m. In latitudinal distribution of the boundary <span class="hlt">layer</span> <span class="hlt">height</span>, there is a characteristic minimum at latitude of ∼ 55° N. For water basins of eight seas, we present the chemical compositions of water-soluble <span class="hlt">aerosol</span> fraction (ions, elements) and small gaseous impurities, as well as estimates of their vertical fluxes. It is shown that substances are mainly (75-89 %) supplied from the atmosphere to the sea surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JAP...120e3302P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JAP...120e3302P&link_type=ABSTRACT"><span id="translatedtitle">Influence of the voltage waveform during nanocomposite <span class="hlt">layer</span> deposition by <span class="hlt">aerosol</span>-assisted atmospheric pressure Townsend discharge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Profili, J.; Levasseur, O.; Naudé, N.; Chaneac, C.; Stafford, L.; Gherardi, N.</p> <p>2016-08-01</p> <p>This work examines the growth dynamics of TiO2-SiO2 nanocomposite coatings in plane-to-plane Dielectric Barrier Discharges (DBDs) at atmospheric pressure operated in a Townsend regime using nebulized TiO2 colloidal suspension in hexamethyldisiloxane as the growth precursors. For low-frequency (LF) sinusoidal voltages applied to the DBD cell, with voltage amplitudes lower than the one required for discharge breakdown, Scanning Electron Microscopy of silicon substrates placed on the bottom DBD electrode reveals significant deposition of TiO2 nanoparticles (NPs) close to the discharge entrance. On the other hand, at higher frequencies (HF), the number of TiO2 NPs deposited strongly decreases due to their "trapping" in the oscillating voltage and their transport along the gas flow lines. Based on these findings, a combined LF-HF voltage waveform is proposed and used to achieve significant and spatially uniform deposition of TiO2 NPs across the whole substrate surface. For higher voltage amplitudes, in the presence of hexamethyldisiloxane and nitrous oxide for plasma-enhanced chemical vapor deposition of inorganic <span class="hlt">layers</span>, it is found that TiO2 NPs become fully embedded into a silica-like matrix. Similar Raman spectra are obtained for as-prepared TiO2 NPs and for nanocomposite TiO2-SiO2 coating, suggesting that plasma exposure does not significantly alter the crystalline structure of the TiO2 NPs injected into the discharge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.A11A0034W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.A11A0034W"><span id="translatedtitle">Modeling <span class="hlt">Aerosol</span> Effects on Shallow Cumuli and Turbulent Activities Under Various Meteorological Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, H.; McFarquhar, G. M.</p> <p>2007-12-01</p> <p>To determine conditions over the Indian Ocean for which cloud fields are most susceptible to modification from <span class="hlt">aerosols</span> and to study how turbulent activities and shallow cumuli vary for different meteorological scenarios, the National Center for Atmospheric Research Eulerian-semi-Lagrangian (EULAG) three-dimensional large-eddy simulation model was initialized using data collected during the Indian Ocean Experiment (INDOEX). Radiosonde data were used to construct 6 soundings encompassing the range of temperature and humidity observed in the trade-wind boundary <span class="hlt">layer</span>. By then adding the characteristics (<span class="hlt">height</span>, depth and strength) of either a typical transition <span class="hlt">layer</span> (TL), a strong inversion <span class="hlt">layer</span> (IL) or no stable <span class="hlt">layer</span> a total of 18 meteorological scenarios were produced. Separate simulations were conducted using EULAG assuming pristine and polluted conditions (i.e., cloud droplet number concentrations, <span class="hlt">aerosol</span> extinction profiles and single-scattering albedos) using INDOEX observations. For the range of meteorological conditions observed during INDOEX, sensitivity studies showed that the semi- direct effect always dominated indirect effects, producing a positive daytime mean net indirect forcing varying between 0.2 and 4.5 W m-2. The simulations showed that changes in the environmental relative humidity (RH) and the presence of the TL had critical impacts on the cloud properties, turbulence and lateral detrainment rates, and on how <span class="hlt">aerosols</span> affect these quantities. The net indirect forcing was larger when the RH was higher and in the absence of any dry and stable <span class="hlt">layers</span>. It was reduced to less than 1.2 W m-2 when the TL was present. The impact of the IL was dependent on convective strength which increases with increasing RH. In fact, changes in meteorological factors had larger impacts on the simulated cloud properties than did the presence of anthropogenic <span class="hlt">aerosols</span>, indicating large uncertainties can be introduced when solely using observations of <span class="hlt">aerosols</span> and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AMT.....9..793E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AMT.....9..793E"><span id="translatedtitle">Global cloud top <span class="hlt">height</span> retrieval using SCIAMACHY limb spectra: model studies and first results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eichmann, Kai-Uwe; Lelli, Luca; von Savigny, Christian; Sembhi, Harjinder; Burrows, John P.</p> <p>2016-03-01</p> <p> observed in limb geometry. Co-located cloud top <span class="hlt">height</span> measurements of the limb-viewing Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on ENVISAT are compared for the period from January 2008 to March 2012. The global CTH agreement of about 1 km is observed, which is smaller than the vertical field of view of both instruments. Lower stratospheric <span class="hlt">aerosols</span> from volcanic eruptions occasionally interfere with the cloud retrieval and inhibit the detection of tropospheric clouds. The <span class="hlt">aerosol</span> impact on cloud retrievals was studied for the volcanoes Kasatochi (August 2008), Sarychev Peak (June 2009), and Nabro (June 2011). Long-lasting <span class="hlt">aerosol</span> scattering is detected after these events in the Northern Hemisphere for <span class="hlt">heights</span> above 12.5 km in tropical and polar latitudes. <span class="hlt">Aerosol</span> top <span class="hlt">heights</span> up to about 22 km are found in 2009 and the enhanced lower stratospheric <span class="hlt">aerosol</span> <span class="hlt">layer</span> persisted for about 7 months. In August 2009 about 82 % of the lower stratosphere between 30 and 70° N was filled with scattering particles and nearly 50 % in October 2008.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AMT.....4.2685W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AMT.....4.2685W"><span id="translatedtitle">Inversion of tropospheric profiles of <span class="hlt">aerosol</span> extinction and HCHO and NO2 mixing ratios from MAX-DOAS observations in Milano during the summer of 2003 and comparison with independent data sets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wagner, T.; Beirle, S.; Brauers, T.; Deutschmann, T.; Frieß, U.; Hak, C.; Halla, J. D.; Heue, K. P.; Junkermann, W.; Li, X.; Platt, U.; Pundt-Gruber, I.</p> <p>2011-12-01</p> <p>We present <span class="hlt">aerosol</span> and trace gas profiles derived from MAX-DOAS observations. Our inversion scheme is based on simple profile parameterisations used as input for an atmospheric radiative transfer model (forward model). From a least squares fit of the forward model to the MAX-DOAS measurements, two profile parameters are retrieved including integrated quantities (<span class="hlt">aerosol</span> optical depth or trace gas vertical column density), and parameters describing the <span class="hlt">height</span> and shape of the respective profiles. From these results, the <span class="hlt">aerosol</span> extinction and trace gas mixing ratios can also be calculated. We apply the profile inversion to MAX-DOAS observations during a measurement campaign in Milano, Italy, September 2003, which allowed simultaneous observations from three telescopes (directed to north, west, south). Profile inversions for <span class="hlt">aerosols</span> and trace gases were possible on 23 days. Especially in the middle of the campaign (17-20 September 2003), enhanced values of <span class="hlt">aerosol</span> optical depth and NO2 and HCHO mixing ratios were found. The retrieved <span class="hlt">layer</span> <span class="hlt">heights</span> were typically similar for HCHO and <span class="hlt">aerosols</span>. For NO2, lower <span class="hlt">layer</span> <span class="hlt">heights</span> were found, which increased during the day. The MAX-DOAS inversion results are compared to independent measurements: (1) <span class="hlt">aerosol</span> optical depth measured at an AERONET station at Ispra; (2) near-surface NO2 and HCHO (formaldehyde) mixing ratios measured by long path DOAS and Hantzsch instruments at Bresso; (3) vertical profiles of HCHO and <span class="hlt">aerosols</span> measured by an ultra light aircraft. Depending on the viewing direction, the <span class="hlt">aerosol</span> optical depths from MAX-DOAS are either smaller or larger than those from AERONET observations. Similar comparison results are found for the MAX-DOAS NO2 mixing ratios versus long path DOAS measurements. In contrast, the MAX-DOAS HCHO mixing ratios are generally higher than those from long path DOAS or Hantzsch instruments. The comparison of the HCHO and <span class="hlt">aerosol</span> profiles from the aircraft showed reasonable agreement with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AMTD....4.3891W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AMTD....4.3891W"><span id="translatedtitle">Inversion of tropospheric profiles of <span class="hlt">aerosol</span> extinction and HCHO and NO2 mixing ratios from MAX-DOAS observations in Milano during the summer of 2003 and comparison with independent data sets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wagner, T.; Beirle, S.; Brauers, T.; Deutschmann, T.; Frieß, U.; Hak, C.; Halla, J. D.; Heue, K. P.; Junkermann, W.; Li, X.; Platt, U.; Pundt-Gruber, I.</p> <p>2011-06-01</p> <p>We present <span class="hlt">aerosol</span> and trace gas profiles derived from MAX-DOAS observations. Our inversion scheme is based on simple profile parameterisations used as input for an atmospheric radiative transfer model (forward model). From a least squares fit of the forward model to the MAX-DOAS measurements, two profile parameters are retrieved including integrated quantities (<span class="hlt">aerosol</span> optical depth or trace gas vertical column density), and parameters describing the <span class="hlt">height</span> and shape of the respective profiles. From these results, the <span class="hlt">aerosol</span> extinction and trace gas mixing ratios can also be calculated. We apply the profile inversion to MAX-DOAS observations during a measurement campaign in Milano, Italy, September 2003, which allowed simultaneous observations from three telescopes (directed to north, west, south). Profile inversions for <span class="hlt">aerosols</span> and trace gases were possible on 23 days. Especially in the middle of the campaign (17-20 September 2003), enhanced values of <span class="hlt">aerosol</span> optical depth and NO2 and HCHO mixing ratios were found. The retrieved <span class="hlt">layer</span> <span class="hlt">heights</span> were typically similar for HCHO and <span class="hlt">aerosols</span>. For NO2, lower <span class="hlt">layer</span> <span class="hlt">heights</span> were found, which increased during the day. The MAX-DOAS inversion results are compared to independent measurements: (1) <span class="hlt">aerosol</span> optical depth measured at an AERONET station at Ispra; (2) near-surface NO2 and HCHO (formaldehyde) mixing ratios measured by long path DOAS and Hantzsch instruments at Bresso; (3) vertical profiles of HCHO and <span class="hlt">aerosols</span> measured by an ultra light aircraft. Depending on the viewing direction, the <span class="hlt">aerosol</span> optical depths from MAX-DOAS are either smaller or larger than those from AERONET observations. Similar comparison results are found for the MAX-DOAS NO2 mixing ratios versus long path DOAS measurements. In contrast, the MAX-DOAS HCHO mixing ratios are generally higher than those from long path DOAS or Hantzsch instruments. The comparison of the HCHO and <span class="hlt">aerosol</span> profiles from the aircraft showed reasonable agreement with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AtmEn.138..191N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AtmEn.138..191N&link_type=ABSTRACT"><span id="translatedtitle">Influence of the vertical absorption profile of mixed Asian dust plumes on <span class="hlt">aerosol</span> direct radiative forcing over East Asia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noh, Young Min; Lee, Kwonho; Kim, Kwanchul; Shin, Sung-Kyun; Müller, Detlef; Shin, Dong Ho</p> <p>2016-08-01</p> <p>We estimate the <span class="hlt">aerosol</span> direct radiative forcing (ADRF) and heating rate profiles of mixed East Asian dust plumes in the solar wavelength region ranging from 0.25 to 4.0 μm using the Santa Barbara Discrete Ordinate Atmospheric Radiative Transfer (SBDART) code. Vertical profiles of <span class="hlt">aerosol</span> extinction coefficients and single-scattering albedos (SSA) were derived from measurements with a multi-wavelength Raman lidar system. The data are used as input parameters for our radiative transfer calculations. We considered four cases of radiative forcing in SBDART: 1. dust, 2. pollution, 3. mixed dust plume and the use of vertical profiles of SSA, and 4. mixed dust plumes and the use of column-averaged values of SSA. In our sensitivity study we examined the influence of SSA and <span class="hlt">aerosol</span> <span class="hlt">layer</span> <span class="hlt">height</span> on our results. The ADRF at the surface and in the atmosphere shows a small dependence on the specific shape of the <span class="hlt">aerosol</span> extinction vertical profile and its light-absorption property for all four cases. In contrast, at the top of the atmosphere (TOA), the ADRF is largely affected by the vertical distribution of the <span class="hlt">aerosols</span> extinction. This effect increases if the light-absorption capacity (decrease of SSA) of the <span class="hlt">aerosols</span> increases. We find different radiative effects in situations in which two <span class="hlt">layers</span> of <span class="hlt">aerosols</span> had different light-absorption properties. The largest difference was observed at the TOA for an absorbing <span class="hlt">aerosol</span> <span class="hlt">layer</span> at high altitude in which we considered in one case the vertical profile of SSA and in another case the column-averaged SSA only. The ADRF at the TOA increases when the light-absorbing <span class="hlt">aerosol</span> <span class="hlt">layer</span> is located above 3 km altitude. The differences between <span class="hlt">height</span>-resolved SSA, which can be obtained from lidar data, and total <span class="hlt">layer</span>-mean SSA indicates that the use of a <span class="hlt">layer</span>-mean SSA can be rather misleading as it can induce a large error in the calculation of the ADRF at the TOA, which in turn may cause errors in the vertical profiles of heating rates.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>