Science.gov

Sample records for aerosol vertical profiles

  1. Modeling of Aerosol Vertical Profiles Using GIS and Remote Sensing

    PubMed Central

    Wong, Man Sing; Nichol, Janet E.; Lee, Kwon Ho

    2009-01-01

    The use of Geographic Information Systems (GIS) and Remote Sensing (RS) by climatologists, environmentalists and urban planners for three dimensional modeling and visualization of the landscape is well established. However no previous study has implemented these techniques for 3D modeling of atmospheric aerosols because air quality data is traditionally measured at ground points, or from satellite images, with no vertical dimension. This study presents a prototype for modeling and visualizing aerosol vertical profiles over a 3D urban landscape in Hong Kong. The method uses a newly developed technique for the derivation of aerosol vertical profiles from AERONET sunphotometer measurements and surface visibility data, and links these to a 3D urban model. This permits automated modeling and visualization of aerosol concentrations at different atmospheric levels over the urban landscape in near-real time. Since the GIS platform permits presentation of the aerosol vertical distribution in 3D, it can be related to the built environment of the city. Examples are given of the applications of the model, including diagnosis of the relative contribution of vehicle emissions to pollution levels in the city, based on increased near-surface concentrations around weekday rush-hour times. The ability to model changes in air quality and visibility from ground level to the top of tall buildings is also demonstrated, and this has implications for energy use and environmental policies for the tall mega-cities of the future. PMID:22408531

  2. Comparison of MADE3-simulated and observed aerosol distributions with a focus on aerosol vertical profiles

    NASA Astrophysics Data System (ADS)

    Kaiser, Christopher; Hendricks, Johannes; Righi, Mattia; Jöckel, Patrick

    2016-04-01

    The reliability of aerosol radiative forcing estimates from climate models depends on the accuracy of simulated global aerosol distribution and composition, as well as on the models' representation of the aerosol-cloud and aerosol-radiation interactions. To help improve on previous modeling studies, we recently developed the new aerosol microphysics submodel MADE3 that explicitly tracks particle mixing state in the Aitken, accumulation, and coarse mode size ranges. We implemented MADE3 into the global atmospheric chemistry general circulation model EMAC and evaluated it by comparison of simulated aerosol properties to observations. Compared properties include continental near-surface aerosol component concentrations and size distributions, continental and marine aerosol vertical profiles, and nearly global aerosol optical depth. Recent studies have shown the specific importance of aerosol vertical profiles for determination of the aerosol radiative forcing. Therefore, our focus here is on the evaluation of simulated vertical profiles. The observational data is taken from campaigns between 1990 and 2011 over the Pacific Ocean, over North and South America, and over Europe. The datasets include black carbon and total aerosol mass mixing ratios, as well as aerosol particle number concentrations. Compared to other models, EMAC with MADE3 yields good agreement with the observations - despite a general high bias of the simulated mass mixing ratio profiles. However, BC concentrations are generally overestimated by many models in the upper troposphere. With MADE3 in EMAC, we find better agreement of the simulated BC profiles with HIPPO data than the multi-model average of the models that took part in the AeroCom project. There is an interesting difference between the profiles from individual campaigns and more "climatological" datasets. For instance, compared to spatially and temporally localized campaigns, the model simulates a more continuous decline in both total

  3. Vertical Profile of Aerosol Properties at Pico Mountain, Azores

    NASA Astrophysics Data System (ADS)

    Wright, K.; Mazzoleni, C.; Mazzoleni, L. R.; Dzepina, K.; Hueber, J.; China, S.; Sharma, N.

    2013-12-01

    Pico Mountain (2325m asl) is a dormant volcano in the archipelago of the Azores1500 km west of Lisbon, Portugal in the North Atlantic. It differs from typical mountain ranges such as the Alps or the Rockies, which are large and present a complex orography. Pico Mountain has a simple cone-like structure with only one main peak and is thousands of kilometers away from any other significant mountain range. In summer months, it is typical for air masses to move around the mountain rather than traveling up its face. This implies that often the peak of the mountain lies above the marine boundary layer in the free troposphere, while the lower part of the mountain is affected by marine clouds and marine air-masses. An atmospheric monitoring station, the Pico Mountain Observatory was established in 2001 in the summit caldera of the volcano at 2225m above sea level. The observatory is far from large populations or pollution sources, which makes the station ideal to study atmospheric gases and aerosols transported over long-ranges in the free troposphere. The station is reachable only by foot following a steep and strenuous hiking trail. In the summer of 2013 we began to collect vertical profiles of aerosol by carrying an instrumented backpack up to the summit of the mountain, with the goal of studying the vertical structure of atmospheric aerosols from the marine boundary layer to the free troposphere. The backpack was carried from the base of trail at 1200m asl. The backpack was equipped with the following instruments: 1. Nephelometer to measure light scattering from aerosol 2. 2-size optical particle counter (300-500 nm) 3. Portable micro-aethalometer to measure absorbing aerosols 4. SEM/TEM sampler to collect particles for off-line electron microscopy analysis 5. Battery powered data logger to measure relative humidity, temperature and pressure 6. GPS tracking device We provide a preliminary analysis of data collected in 2013 to gain insight on the vertical distribution

  4. Global profiles of the direct aerosol effect using vertically resolved aerosol data

    NASA Astrophysics Data System (ADS)

    Korras Carraca, Marios Bruno; Pappas, Vasilios; Matsoukas, Christos; Hatzianastassiou, Nikolaos; Vardavas, Ilias

    2014-05-01

    Atmospheric aerosols, both natural and anthropogenic, can cause climate change through their direct, indirect, and semi-direct effects on the radiative energy budget of the Earth-atmosphere system. In general, aerosols cause cooling of the surface and the planet, while they warm the atmosphere due to scattering and absorption of incoming solar radiation. The importance of vertically resolved direct radiative effect (DRE) and heating/cooling effects of aerosols is strong, while large uncertainties still lie with their magnitudes. In order to be able to quantify them throughout the atmosphere, a detailed vertical profile of the aerosol effect is required. Such data were made available recently by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. CALIOP is the first polarization lidar to fly in space and has been acquiring unique data on aerosols and clouds since June 2006. The aim of this study is to investigate both the vertically resolved geographic and seasonal variation of the DRE due to aerosols. The vertical profile of DRE under all-sky and clear-sky conditions is computed using the deterministic spectral radiative transfer model FORTH. From the DRE, the effect on atmospheric heating/cooling rate profiles due to aerosols can also be derived. We use CALIOP Level 2-Version 3 Layer aerosol optical depth data as input to our radiation transfer model, for a period of 3 complete years (2007-2009). These data are provided on a 5 km horizontal resolution and in up to 8 vertical layers and have been regridded on our model horizontal and vertical resolutions. We use cloud data from the International Satellite Cloud Climatology Project (ISCCP), while the aerosol asymmetry factor and single scattering albedo are taken from the Global Aerosol Data Set (GADS). The model computations are performed on a monthly, 2.5°× 2.5° resolution on global scale, at 40

  5. Radiosonde aerosol counter for vertical profiling of atmospheric dust layers

    NASA Astrophysics Data System (ADS)

    Ulanowski, Z.; Hirst, E.; Kaye, P. H.; Harrison, R. G.; Nicoll, K. A.; Rogers, G.

    2010-05-01

    A low-cost, miniature aerosol 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%.

  6. Vertical Profiles of Aerosol Volume from High Spectral Resolution Infrared Transmission Measurements: Results

    NASA Technical Reports Server (NTRS)

    Eldering, Annmarie; Kahn, Brian H.; Mills, Franklin P.; Irion, Fredrick W.; Steele, Helen M.; Gunson, Michael R.

    2004-01-01

    The high-resolution infrared absorption spectra of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment are utilized to derive vertical profiles of sulfate aerosol volume density and extinction coefficient. Following the eruption of Mt. Pinatubo in June 1991, the ATMOS spectra obtained on three Space Shuttle missions (1992, 1993, and 1994) provide a unique opportunity to study the global stratospheric sulfate aerosol layer shortly after a major volcanic eruption and periodically during the decay phase. Synthetic sulfate aerosol spectra are fit to the observed spectra, and a global fitting inversion routine is used to derive vertical profiles of sulfate aerosol volume density. Vertical profiles of sulfate aerosol volume density for the three missions over portions of the globe are presented, with the peak in aerosol volume density occurring from as low as 10 km (polar latitudes) to as high as 20 km (subtropical latitudes). Derived aerosol volume density is as high as 2-3.5 (mu)m(exp 3) per cubic centimeter +/-10% in 1992, decreasing to 0.2-0.5 (mu)m(exp 3) per cubic centimeter +/-20% in 1994, in agreement with other experiments. Vertical extinction profiles derived from ATMOS are compared with profiles from Improved Stratospheric And Mesospheric Sounder (ISAMS) and Cryogenic Limb Array Etalon Spectrometer (CLAES) that coincide in space and time and show good general agreement. The uncertainty of the ATMOS vertical profiles is similar to CLAES and consistently smaller than ISAMS at similar altitudes.

  7. Vertical profiles of cloud condensation nuclei, aerosol hygroscopicity, water uptake, and scattering across the United States

    NASA Astrophysics Data System (ADS)

    Lin, J. J.; Bougiatioti, A.; Nenes, A.; Anderson, B. E.; Beyersdorf, A. J.; Brock, C. A.; Gordon, T. D.; Lack, D.; Law, D. C.; Liao, J.; Middlebrook, A. M.; Richardson, M.; Thornhill, K. L., II; Winstead, E.; Wagner, N. L.; Welti, A.; Ziemba, L. D.

    2014-12-01

    The evolutions of vertical distributions of aerosol chemical, microphysical, hygroscopic, and optical properties present fundamental challenges to the understanding of ground-level air quality and radiative transfer, and few datasets exist to date for evaluation of atmospheric models. Data collected from recent NASA and NOAA field campaigns in the California Central Valley (DISCOVER-AQ), southeast United States (SENEX, SEAC4RS) and Texas (DISCOVER-AQ) allow for a unique opportunity to constrain vertical profiles of climate-relevant aerosol properties. This work presents in-situ aircraft measurements of cloud condensation nuclei (CCN) concentration and derivations of aerosol hygroscopicity, water uptake, and light scattering. Aerosol hygroscopicity is derived from CCN and aerosol measurements. Inorganic water uptake is calculated from aerosol composition using ISORROPIA, a chemical thermodynamic model, while organic water uptake is calculated from organic hygroscopicity. Aerosol scattering closure is performed between scattering from water uptake calculations and in-situ scattering measurements.

  8. Measurements of Aerosol Vertical Profiles and Optical Properties during INDOEX 1999 Using Micro-Pulse Lidars

    NASA Technical Reports Server (NTRS)

    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)

    2001-01-01

    lower troposphere) calculates extinction near the surface in agreement with the ship-level measurements only when the MBL aerosols are well mixed with aerosols above. Finally, a review of the MPL extinction profiles showed that the model of aerosol vertical extinction developed during an earlier INDOEX field campaign (at the Maldives) did not correctly describe the true vertical distribution over the greater Indian Ocean region. Using the average extinction profile and AOD obtained during marine conditions, a new model of aerosol vertical extinction was determined for marine atmospheres over the Indian Ocean. A new model of aerosol vertical extinction for polluted marine atmospheres was also developed using the average extinction profile and AOD obtained during marine conditions influenced by continental aerosols.

  9. The effect of aerosol vertical profiles on satellite-estimated surface particle sulfate concentrations

    SciTech Connect

    Liu, Yang; Wang, Zifeng; Wang, Jun; Ferrare, Richard A.; Newsom, Rob K.; Welton, Ellsworth J.

    2011-02-15

    The aerosol vertical distribution is an important factor in determining the relationship between satellite retrieved aerosol optical depth (AOD) and ground-level fine particle pollution concentrations. We evaluate how aerosol profiles measured by ground-based lidar and simulated by models can help improve the association between AOD retrieved by the Multi-angle Imaging Spectroradiometer (MISR) and fine particle sulfate (SO4) concentrations using matched data at two lidar sites. At the Goddard Space Flight Center (GSFC) site, both lidar and model aerosol profiles marginally improve the association between SO4 concentrations and MISR fractional AODs, as the correlation coefficient between cross-validation (CV) and observed SO4 concentrations changes from 0.87 for the no-scaling model to 0.88 for models scaled with aerosol vertical profiles. At the GSFC site, a large amount of urban aerosols resides in the well-mixed boundary layer so the column fractional AODs are already excellent indicators of ground-level particle pollution. In contrast, at the Atmospheric Radiation Measurement Program (ARM) site with relatively low aerosol loadings, scaling substantially improves model performance. The correlation coefficient between CV and observed SO4 concentrations is increased from 0.58 for the no-scaling model to 0.76 in the GEOS-Chem scaling model, and the model bias is reduced from 17% to 9%. In summary, despite the inaccuracy due to the coarse horizontal resolution and the challenges of simulating turbulent mixing in the boundary layer, GEOS-Chem simulated aerosol profiles can still improve methods for estimating surface aerosol (SO4) mass from satellite-based AODs, particularly in rural areas where aerosols in the free troposphere and any long-range transport of aerosols can significantly contribute to the column AOD.

  10. Long-term aerosol study on continental scale through EARLINET vertical profiles

    NASA Astrophysics Data System (ADS)

    Mona, Lucia; Pappalardo, Gelsomina; Linne, Holger; Wandinger, Ulla

    2015-04-01

    Lidar techniques offer the opportunity for investigating the aerosol vertical profiles, which is an important information for climatological, meteorological and air quality issues. EARLINET (European Aerosol Research Lidar Network) has been providing aerosol optical properties vertical profiles over Europe since May 2000. Long-term aerosol observations performed within EARLINET allows a climatological study of aerosol properties over Europe. All EARLINET stations perform almost simultaneously measurements three times per week following a scheduling established in 2000. Besides these climatological measurements, additional measurements are performed in order to monitor special events (as volcanic eruptions and desert dust intrusion), for satellite data evaluation and integrated studies and during intensive measurements campaigns. Aerosol optical properties vertical profiles are freely available at www.earlinet.org and through ACRIS data center http://www.actris.net/. This data are currently published on the CERA database with an associated doi number. Based mainly on Raman technique, EARLINET stations typically provide direct measurement of extinction profiles, and therefore of the aerosol optical depth (AOD), a key parameter for understanding the aerosol role on radiation budget. The free troposphere contribution to AOD and altitude of lofted layers are provided thanks to the vertical profiling capability of lidar technique. The representativeness of EARLINET regular scheduling for climatological studies is investigating through the comparison with AERONET and MODIS measurements. We find that the regular measurements schedule is typically sufficient for climatological studies. In addition lidar punctual measurements are representative for a larger area (1°x1°) in a climatological sense. Long term analysis of EARLINET profiles shows that the AOD in generally decreasing over Europe in agreement with both passive-sensors and in situ measurements. Mean vertical

  11. Vertical profiles of urban aerosol complex refractive index in the frame of ESQUIF airborne measurements

    NASA Astrophysics Data System (ADS)

    Raut, J.-C.; Chazette, P.

    2007-07-01

    A synergy between lidar, sunphotometer and in situ measurements has been applied to airborne observations performed during the Etude et Simulation de la QUalité de l'air en Ile-de-France (ESQUIF), enabling the retrieval of vertical profiles for the aerosol complex refractive index (ACRI) and single-scattering albedo with a vertical resolution of 200 m over Paris area. The averaged value over the entire planetary boundary layer (PBL) for the ACRI is close to 1.51(±0.02)-i0.017(±0.003) at 532 nm. The single-scattering albedo of the corresponding aerosols is found to be ~0.9 at the same wavelength. A good agreement is found with previous studies for urban aerosols. A comparison of vertical profiles of ACRI with simulations combining in situ measurements and relative humidity (RH) profiles has highlighted a modification in aerosol optical properties linked to their history and the origin of the air mass. The determination of ACRI in the atmospheric column enabled to retrieve vertical profiles of extinction coefficient in accordance with lidar profiles measurements.

  12. Vertical profiles of urban aerosol complex refractive index in the frame of ESQUIF airborne measurements

    NASA Astrophysics Data System (ADS)

    Raut, J.-C.; Chazette, P.

    2008-02-01

    A synergy between lidar, sunphotometer and in situ measurements has been applied to airborne observations performed during the Etude et Simulation de la QUalité de l'air en Ile-de-France (ESQUIF), enabling the retrieval of vertical profiles for the aerosol complex refractive index (ACRI) and single-scattering albedo with a vertical resolution of 200 m over Paris area. The averaged value over the entire planetary boundary layer (PBL) for the ACRI is close to 1.51(±0.02)-i0.017(±0.003) at 532 nm. The single-scattering albedo of the corresponding aerosols is found to be ~0.9 at the same wavelength. A good agreement is found with previous studies for urban aerosols. A comparison of vertical profiles of ACRI with simulations combining in situ measurements and relative humidity (RH) profiles has highlighted a modification in aerosol optical properties linked to their history and the origin of the air mass. The determination of ACRI in the atmospheric column enabled to retrieve vertical profiles of extinction coefficient in accordance with lidar profiles measurements.

  13. Hemispheric aerosol vertical profiles: anthropogenic impacts on optical depth and cloud nuclei.

    PubMed

    Clarke, Antony; Kapustin, Vladimir

    2010-09-17

    Understanding the effect of anthropogenic combustion upon aerosol optical depth (AOD), clouds, and their radiative forcing requires regionally representative aerosol profiles. In this work, we examine more than 1000 vertical profiles from 11 major airborne campaigns in the Pacific hemisphere and confirm that regional enhancements in aerosol light scattering, mass, and number are associated with carbon monoxide from combustion and can exceed values in unperturbed regions by more than one order of magnitude. Related regional increases in a proxy for cloud condensation nuclei (CCN) and AOD imply that direct and indirect aerosol radiative effects are coupled issues linked globally to aged combustion. These profiles constrain the influence of combustion on regional AOD and CCN suitable for challenging climate model performance and informing satellite retrievals.

  14. Aerosols and lightning activity: The effect of vertical profile and aerosol type

    NASA Astrophysics Data System (ADS)

    Proestakis, E.; Kazadzis, S.; Lagouvardos, K.; Kotroni, V.; Amiridis, V.; Marinou, E.; Price, C.; Kazantzidis, A.

    2016-12-01

    The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite has been utilized for the first time in a study regarding lightning activity modulation due to aerosols. Lightning activity observations, obtained by the ZEUS long range Lightning Detection Network, European Centre for Medium range Weather Forecasts (ECMWF) Convective Available Potential Energy (CAPE) data and Cloud Fraction (CF) retrieved by MODIS on board Aqua satellite have been combined with CALIPSO CALIOP data over the Mediterranean basin and for the period March to November, from 2007 to 2014. The results indicate that lightning activity is enhanced during days characterized by higher Aerosol Optical Depth (AOD) values, compared to days with no lightning. This study contributes to existing studies on the link between lightning activity and aerosols, which have been based just on columnar AOD satellite retrievals, by performing a deeper analysis into the effect of aerosol profiles and aerosol types. Correlation coefficients of R = 0.73 between the CALIPSO AOD and the number of lightning strikes detected by ZEUS and of R = 0.93 between ECMWF CAPE and lightning activity are obtained. The analysis of extinction coefficient values at 532 nm indicates that at an altitudinal range exists, between 1.1 km and 2.9 km, where the values for extinction coefficient of lightning-active and non-lightning-active cases are statistically significantly different. Finally, based on the CALIPSO aerosol subtype classification, we have investigated the aerosol conditions of lightning-active and non-lightning-active cases. According to the results polluted dust aerosols are more frequently observed during non-lightning-active days, while dust and smoke aerosols are more abundant in the atmosphere during the lightning-active days.

  15. Vertical Profiles of Aerosol Optical Properties Over Central Illinois and Comparison with Surface and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Sheridan P. J.; Andrews, E.; Ogren, J A.; Tackett, J. L.; Winker, D. M.

    2012-01-01

    Between June 2006 and September 2009, an instrumented light aircraft measured over 400 vertical profiles of aerosol and trace gas properties over eastern and central Illinois. The primary objectives of this program were to (1) measure the in situ aerosol properties and determine their vertical and temporal variability and (2) relate these aircraft measurements to concurrent surface and satellite measurements. Underflights of the CALIPSO satellite show reasonable agreement in a majority of retrieved profiles between aircraft-measured extinction at 532 nm (adjusted to ambient relative humidity) and CALIPSO-retrieved extinction, and suggest that routine aircraft profiling programs can be used to better understand and validate satellite retrieval algorithms. CALIPSO tended to overestimate the aerosol extinction at this location in some boundary layer flight segments when scattered or broken clouds were present, which could be related to problems with CALIPSO cloud screening methods. The in situ aircraft-collected aerosol data suggest extinction thresholds for the likelihood of aerosol layers being detected by the CALIOP lidar. These statistical data offer guidance as to the likelihood of CALIPSO's ability to retrieve aerosol extinction at various locations around the globe.

  16. Vertical profiles of aerosol volume from high-spectral-resolution infrared transmission measurements. I. Methodology.

    PubMed

    Eldering, A; Irion, F W; Chang, A Y; Gunson, M R; Mills, F P; Steele, H M

    2001-06-20

    The wavelength-dependent aerosol extinction in the 800-1250-cm(-1) region has been derived from ATMOS (atmospheric trace molecule spectroscopy) high-spectral-resolution IR transmission measurements. Using models of aerosol and cloud extinction, we have performed weighted nonlinear least-squares fitting to determine the aerosol-volume columns and vertical profiles of stratospheric sulfate aerosol and cirrus cloud volume. Modeled extinction by use of cold-temperature aerosol optical constants for a 70-80% sulfuric-acid-water solution shows good agreement with the measurements, and the derived aerosol volumes for a 1992 occultation are consistent with data from other experiments after the eruption of Mt. Pinatubo. The retrieved sulfuric acid aerosol-volume profiles are insensitive to the aerosol-size distribution and somewhat sensitive to the set of optical constants used. Data from the nonspherical cirrus extinction model agree well with a 1994 mid-latitude measurement indicating the presence of cirrus clouds at the tropopause.

  17. Investigation the optical and radiative properties of aerosol vertical profile of boundary layer by lidar and ground based measurements

    NASA Astrophysics Data System (ADS)

    Chen, W.; Chou, C.; Lin, P.; Wang, S.

    2011-12-01

    The planetary boundary layer is the air layer near the ground directly affected by diurnal heat, moisture, aerosol, and cloud transfer to or from the surface. In the daytime solar radiation heats the surface, initiating thermal instability or convection. Whereas, the scattering and absorption of aerosols or clouds might decrease the surface radiation or heat atmosphere which induce feedbacks such as the enhanced stratification and change in relative humidity in the boundary layer. This study is aimed to understand the possible radiative effect of aerosols basing on ground based aerosol measurements and lidar installed in National Taiwan University in Taipei. The optical and radiative properties of aerosols are dominated by aerosol composition, particle size, hygroscopicity property, and shape. In this study, aerosol instruments including integrating nephelometer, open air nephelometer, aethalometer are applied to investigate the relationship between aerosol hygroscopicity properties and aerosol types. The aerosol hygroscopicity properties are further applied to investigate the effect of relative humidity on aerosol vertical profiles measured by a dual-wavelength and depolarization lidar. The possible radiative effect of aerosols are approached by vertical atmospheric extinction profiles measured by lidar. Calculated atmospheric and aerosol heating effects was compared with vertical meteorological parameters measured by radiosonde. The result shows light-absorbing aerosol has the potential to affect the stability of planetary boundary layer.

  18. Wintertime characteristics of aerosols over middle Indo-Gangetic Plain: Vertical profile, transport and radiative forcing

    NASA Astrophysics Data System (ADS)

    Kumar, M.; Raju, M. P.; Singh, R. K.; Singh, A. K.; Singh, R. S.; Banerjee, T.

    2017-01-01

    Winter-specific characteristics of airborne particulates over middle Indo-Gangetic Plain (IGP) were evaluated in terms of aerosol chemical and micro-physical properties under three-dimensional domain. Emphases were made for the first time to identify intra-seasonal variations of aerosols sources, horizontal and vertical transport, effects of regional meteorology and estimating composite aerosol short-wave radiative forcing over an urban region (25°10‧-25°19‧N; 82°54‧-83°4‧E) at middle-IGP. Space-borne passive (Aqua and Terra MODIS, Aura OMI) and active sensor (CALIPSO-CALIOP) based observations were concurrently used with ground based aerosol mass measurement for entire winter and pre-summer months (December, 1, 2014 to March, 31, 2015). Exceptionally high aerosol mass loading was recorded for both PM10 (267.6 ± 107.0 μg m- 3) and PM2.5 (150.2 ± 89.4 μg m- 3) typically exceeding national standard. Aerosol type was mostly dominated by fine particulates (particulate ratio: 0.61) during pre to mid-winter episodes before being converted to mixed aerosol types (ratio: 0.41-0.53). Time series analysis of aerosols mass typically identified three dissimilar aerosol loading episodes with varying attributes, well resemble to that of previous year's observation representing its persisting nature. Black carbon (9.4 ± 3.7 μg m- 3) was found to constitute significant proportion of fine particulates (2-27%) with a strong diurnal profile. Secondary inorganic ions also accounted a fraction of particulates (PM2.5: 22.5%; PM10: 26.9%) having SO4- 2, NO3- and NH4+ constituting major proportion. Satellite retrieved MODIS-AOD (0.01-2.30) and fine mode fractions (FMF: 0.01-1.00) identified intra-seasonal variation with transport of aerosols from upper to middle-IGP through continental westerly. Varying statistical association of columnar and surface aerosol loading both in terms of fine (r; PM2.5: MODIS-AOD: 0.51) and coarse particulates (PM10: MODIS-AOD: 0.53) was

  19. ACTRIS aerosol vertical profile data and observations: potentiality and first examples of integrated studies with models

    NASA Astrophysics Data System (ADS)

    Mona, Lucia; Benedetti, Angela; D'Amico, Giuseppe; Myhre, Cathrine Lund; Schulz, Michael; Wandinger, Ulla; Laj, Paolo; Pappalardo, Gelsomina

    2016-04-01

    The ACTRIS-2 project, funded by Horizon 2020, addresses the scope of integrating state-of-the-art European ground-based stations for long term observations of aerosols, clouds and short lived gases, capitalizing on the work of FP7-ACTRIS. It aims at achieving the construction of a user-oriented RI, unique in the EU-RI landscape for providing 4-D integrated high-quality data from near-surface to high altitude (vertical profiles and total-column) which are relevant to climate and air-quality research. ACTRIS-2 develops and implements, in a large network of stations in Europe and beyond, observational protocols that permit the harmonization of collected data and their dissemination. ACTRIS secures provision and dissemination of a unique set of data and data-products that would not otherwise be available with the same level of quality and standardization. This results from a 10-year plus effort in constructing a research infrastructure capable of responding to community needs and requirements, and has been engaged since the start of the FP5 EU commission program. ACTRIS ensures compliance with reporting requirements (timing, format, traceability) defined by the major global observing networks. EARLINET (European Aerosol research Lidar NETwork), the aerosol vertical profiling component of ACTRIS, is providing since May 2000 vertical profiles of aerosol extinction and backscatter over Europe. A new structure of the EARLINET database has been designed in a more user oriented approach reporting new data products which are more effective for specific uses of different communities. In particular, a new era is starting with the Copernicus program during which the aerosol vertical profiling capability will be fundamental for assimilation and validation purposes. The new data products have been designed thanks to a strong link with EARLINET data users, first of all modeling and satellite communities, established since the beginning of EARLINET and re-enforced within ACTRIS2

  20. How well can we Measure the Vertical Profile of Tropospheric Aerosol Extinction?

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Ferrare, R.; Flynn, C.; Elleman, R.; Covert, D.; Strawa, A.; Welton, E.; Turner, D.; Jonsson, H.; Redemann, J.

    2005-01-01

    The recent Department of Energy Atmospheric Radiation Measurement (ARM) Aerosol Intensive Operations Period (MOP, May 2003) yielded one of the best measurement sets obtained to-date to assess our ability to measure the vertical profile of ambient aerosol extinction sigma(sub ep)(lambda) in the lower troposphere. During one month, a heavily instrumented aircraft with well characterized aerosol sampling ability carrying well proven and new aerosol instrumentation, devoted most of the 60 available flight hours to flying vertical profiles over the heavily instrumented ARM Southern Great Plains (SGP) Climate Research Facility (CRF). This allowed us to compare vertical extinction profiles obtained from 6 different instuments: airborne Sun photometer (AATS-14), airborne nephelometer/absorption photometer, airborne cavity ring-down system, ground-based Raman lidar and 2 ground-based elastic backscatter lidars. We find the in-situ measured sigma(sub ep)(lambda) to be lower than the AATS-14 derived values. Bias differences are 0.002 - 0.004 K/m equivalent to 12-17% in the visible, or 45% in the near-infrared. On the other hand, we find that with respect to AATS-14, the lidar sigma(sub ep)(lambda) are higher. An unnoticed loss of sensitivity of the Raman lidar had occurred leading up to AIOP and we expect better agreement from the recently restored system looking at the collective results from 6 field campaigns conducted since 1996, airborne in situ measurements of sigma(sub ep)(lambda) tend to be biased slightly low (17% at visible wavelengths) when compared to airborne Sun photometer sigma(sub ep)(lambda). On the other hand, sigma(sub ep)(lambda) values derived from lidars tend to have no or positive biases. From the bias differences we conclude that the typical systematic error associated with measuring the tropospheric vertical profile of the ambient aerosol extinction with current state of-the art instrumentation is 15-20% at visible wavelengths and potentially larger in

  1. Vertical profiles of aerosol optical properties and the solar heating rate estimated by combining sky radiometer and lidar measurements

    NASA Astrophysics Data System (ADS)

    Kudo, Rei; Nishizawa, Tomoaki; Aoyagi, Toshinori

    2016-07-01

    The SKYLIDAR algorithm was developed to estimate vertical profiles of aerosol optical properties from sky radiometer (SKYNET) and lidar (AD-Net) measurements. The solar heating rate was also estimated from the SKYLIDAR retrievals. The algorithm consists of two retrieval steps: (1) columnar properties are retrieved from the sky radiometer measurements and the vertically mean depolarization ratio obtained from the lidar measurements and (2) vertical profiles are retrieved from the lidar measurements and the results of the first step. The derived parameters are the vertical profiles of the size distribution, refractive index (real and imaginary parts), extinction coefficient, single-scattering albedo, and asymmetry factor. Sensitivity tests were conducted by applying the SKYLIDAR algorithm to the simulated sky radiometer and lidar data for vertical profiles of three different aerosols, continental average, transported dust, and pollution aerosols. The vertical profiles of the size distribution, extinction coefficient, and asymmetry factor were well estimated in all cases. The vertical profiles of the refractive index and single-scattering albedo of transported dust, but not those of transported pollution aerosol, were well estimated. To demonstrate the performance and validity of the SKYLIDAR algorithm, we applied the SKYLIDAR algorithm to the actual measurements at Tsukuba, Japan. The detailed vertical structures of the aerosol optical properties and solar heating rate of transported dust and smoke were investigated. Examination of the relationship between the solar heating rate and the aerosol optical properties showed that the vertical profile of the asymmetry factor played an important role in creating vertical variation in the solar heating rate. We then compared the columnar optical properties retrieved with the SKYLIDAR algorithm to those produced with the more established scheme SKYRAD.PACK, and the surface solar irradiance calculated from the SKYLIDAR

  2. Vertical profiling of aerosol hygroscopic properties in the planetary boundary layer during the PEGASOS campaigns

    NASA Astrophysics Data System (ADS)

    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

    2016-06-01

    Vertical profiles of the aerosol particles hygroscopic properties, their mixing state as well as chemical composition were measured above northern Italy and the Netherlands. An aerosol 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 layers within the planetary boundary layer (PBL), providing a unique in situ data set for airborne aerosol 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 aerosol 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-layers with different types of aerosols. Later in the day the vertical structures disappeared due to the mixing of the layers and similar aerosol particle properties were found at all probed altitudes (mean κ ≈ 0.18 ± 0.07). The aerosol 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 aerosol 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

  3. Vertical Profiling of Atmospheric Backscatter with a Raman-Aerosol Lidar

    NASA Astrophysics Data System (ADS)

    Deleva, Atanaska D.; Peshev, Zahary Y.; Slesar, Alexander S.; Denisov, Sergey; Avramov, Lachezar A.; Stoyanov, Dimitar V.

    2010-01-01

    Aerosols have a strong impact on the planet's thermal balance, air quality, and a variety of atmospheric processes and phenomena. In this work we present some results from a long term lidar observation of tropospheric aerosols over the city of Sofia, Bulgaria, within the framework of the European project "EARLINET-ASSOS." Vertical profiles of the aerosol backscattering coefficient and range corrected lidar signals are processed and analyzed. The temporal evolution and the spatial distribution of atmospheric aerosol fields are illustrated by 2D-colormaps in height-time coordinates. We present here several cases of aerosol loading: transport of Saharan dust (at altitudes from 3 km to 5 km), highly situated layers (from 9 km to 15 km), and anthropogenic smog (up to 2 km). All measurements were performed by using the two aerosol spectral channels of a combined Raman-aerosol lidar developed in the Laser Radar Lab, Institute of Electronics, Bulgarian Academy of Sciences. It is based on a Q-switched powerful frequency-doubled Nd:YAG laser (output pulse power: up to 1 J at 1064 nm; up to 100 mJ at 532 nm; pulse duration 15 ns FWHM; repetition rate 2 Hz). A Cassegrain telescope (35 cm diameter, 200 cm focal length) collects the backscattered radiation. The lidar receiving system is based on novel smart high sensitive photo-receiving modules. The acquisition system provides signal registration with spatial resolution of 15 m (100 MHz 14-bit ADC). It allows for detection, storage, and processing of large volume lidar data. Our observations are in good agreement with the forecasts of Barcelona Supercomputing Center, concerning Saharan dust transport.

  4. The CU Airborne MAX-DOAS instrument: vertical profiling of aerosol extinction and trace gases

    NASA Astrophysics Data System (ADS)

    Baidar, S.; Oetjen, H.; Coburn, S.; Dix, B.; Ortega, I.; Sinreich, R.; Volkamer, R.

    2013-03-01

    The University of Colorado Airborne Multi-Axis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument uses solar stray light to detect and quantify multiple trace gases, including nitrogen dioxide (NO2), glyoxal (CHOCHO), formaldehyde (HCHO), water vapor (H2O), nitrous acid (HONO), iodine monoxide (IO), bromine monoxide (BrO), and oxygen dimers (O4) at multiple wavelengths (absorption bands at 360, 477, 577, 632 nm) simultaneously in the open atmosphere. The instrument is unique as it (1) features a motion compensation system that decouples the telescope field of view from aircraft movements in real time (<0.35° accuracy), and (2) includes measurements of solar stray light photons from nadir, zenith, and multiple elevation angles forward and below the plane by the same spectrometer/detector system. Sets of solar stray light spectra collected from nadir to zenith scans provide some vertical profile information within 2 km above and below the aircraft altitude, and the vertical column density (VCD) below the aircraft is measured in nadir view. Maximum information about vertical profiles is derived simultaneously for trace gas concentrations and aerosol extinction coefficients over similar spatial scales and with a vertical resolution of typically 250 m during aircraft ascent/descent. The instrument is described, and data from flights over California during the CalNex (California Research at the Nexus of Air Quality and Climate Change) and CARES (Carbonaceous Aerosols and Radiative Effects Study) air quality field campaigns is presented. Horizontal distributions of NO2 VCD (below the aircraft) maps are sampled with typically 1 km resolution, and show good agreement with two ground-based MAX-DOAS instruments (slope = 0.95 ± 0.09, R2 = 0.86). As a case study vertical profiles of NO2, CHOCHO, HCHO, and H2O concentrations and aerosol extinction coefficients, ɛ, at 477 nm calculated from O4 measurements from a low approach at Brackett airfield inside the

  5. Estimation of surface-level PM concentration from satellite observation taking into account the aerosol vertical profiles and hygroscopicity.

    PubMed

    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

    2016-01-01

    Surface-level PM10 distribution was estimated from the satellite aerosol optical depth (AOD) products, taking the account of vertical profiles and hygroscopicity of aerosols over Jeju, Korea during March 2008 and October 2009. In this study, MODIS AOD data from the Terra and Aqua satellites were corrected with aerosol extinction profiles and relative humidity data. PBLH (Planetary Boundary Layer Height) was determined from MPLNET lidar-derived aerosol 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 Layer Height (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.

  6. Near Real Time Vertical Profiles of Clouds and Aerosols from the Cloud-Aerosol Transport System (CATS) on the International Space Station

    NASA Astrophysics Data System (ADS)

    Yorks, J. E.; McGill, M. J.; Nowottnick, E. P.

    2015-12-01

    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 aerosol transport models are very useful for tracking hazardous plumes and predicting the transport of these plumes. However aerosol vertical distributions and optical properties are a major weakness of global aerosol transport models, yet a key component of tracking and forecasting smoke and ash. The Cloud-Aerosol Transport System (CATS) is an elastic backscatter lidar designed to provide vertical profiles of clouds and aerosols 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 aerosol transport tracks, mid-latitude storm tracks, and tropical convection. Data from CATS is used to derive properties of clouds and aerosols including: layer height, layer thickness, backscatter, optical depth, extinction, and depolarization-based discrimination of particle type. The measurements of atmospheric clouds and aerosols provided by the CATS payload have demonstrated several science benefits. CATS provides near-real-time observations of cloud and aerosol 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

  7. Vertical profiling of aerosol hygroscopic properties in the planetary boundary layer during the PEGASOS campaigns

    NASA Astrophysics Data System (ADS)

    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.

    2015-03-01

    Airborne measurements of the aerosol 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 aerosol properties during the development of the mixing layer 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 aerosol mass spectrometer (AMS) and an aethalometer providing information on the aerosol 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 layer (newly developing mixing layer) contained a high nitrate fraction (20%) which was coupled with enhanced hygroscopic growth. In the layer above (residual layer) small nitrate fractions of ~ 2% were measured as well as low GFs. After full mixing of the layers, 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 layer. These distinct vertical and temporal changes underline the importance of airborne campaigns to study aerosol properties during the development of the mixed layer. The aerosol 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 layer, residual layer and fully mixed layer, respectively. These results agree well with those from chemical analysis which found values of κ = 0.27, 0.21 and 0

  8. A sensitivity study on the retrieval of aerosol vertical profiles using the oxygen A-band

    NASA Astrophysics Data System (ADS)

    Fedele Colosimo, Santo; Natraj, Vijay; Sander, Stanley P.; Stutz, Jochen

    2016-04-01

    Atmospheric absorption in the O2 A-band (12 950-13 200 cm-1) offers a unique opportunity to retrieve aerosol extinction profiles from space-borne measurements due to the large dynamic range of optical thickness in that spectral region. Absorptions in strong O2 lines are saturated; therefore, any radiance measured in these lines originates from scattering in the upper part of the atmosphere. Outside of O2 lines, or in weak lines, the atmospheric column absorption is small, and light penetrates to lower atmospheric layers, allowing for the quantification of aerosols and other scatterers near the surface.

    While the principle of aerosol profile retrieval using O2 A-band absorption from space is well-known, a thorough quantification of the information content, i.e., the amount of vertical profile information that can be obtained, and the dependence of the information content on the spectral resolution of the measurements, has not been thoroughly conducted. Here, we use the linearized vector radiative transfer model VLIDORT to perform spectrally resolved simulations of atmospheric radiation in the O2 A-band for four different aerosol extinction profile scenarios: urban (urban-rural areas), highly polluted (megacity areas with large aerosol extinction), elevated layer (identifying elevated plumes, for example for biomass burning) and low extinction (representative of small aerosol extinction, such as vegetated, marine and arctic areas). The high-resolution radiances emerging from the top of the atmosphere measurements are degraded to different spectral resolutions, simulating spectrometers with different resolving powers. We use optimal estimation theory to quantify the information content in the aerosol profile retrieval with respect to different aerosol parameters and instrument spectral resolutions. The simulations show that better spectral resolution generally leads to an increase in the total amount of information that can be retrieved, with the number of

  9. Influence of the vertical absorption profile of mixed Asian dust plumes on aerosol direct radiative forcing over East Asia

    NASA Astrophysics Data System (ADS)

    Noh, Young Min; Lee, Kwonho; Kim, Kwanchul; Shin, Sung-Kyun; Müller, Detlef; Shin, Dong Ho

    2016-08-01

    We estimate the aerosol 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 aerosol 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 aerosol layer height on our results. The ADRF at the surface and in the atmosphere shows a small dependence on the specific shape of the aerosol 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 aerosols extinction. This effect increases if the light-absorption capacity (decrease of SSA) of the aerosols increases. We find different radiative effects in situations in which two layers of aerosols had different light-absorption properties. The largest difference was observed at the TOA for an absorbing aerosol layer 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 aerosol layer is located above 3 km altitude. The differences between height-resolved SSA, which can be obtained from lidar data, and total layer-mean SSA indicates that the use of a layer-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.

  10. In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC4RS: observations of a modest aerosol enhancement aloft

    NASA Astrophysics Data System (ADS)

    Wagner, N. L.; Brock, C. A.; Angevine, W. M.; Beyersdorf, A.; Campuzano-Jost, P.; Day, D. A.; de Gouw, J. A.; Diskin, G. S.; Gordon, T. D.; Graus, M. G.; Huey, G.; Jimenez, J. L.; Lack, D. A.; Liao, J.; Liu, X.; Markovic, M. Z.; Middlebrook, A. M.; Mikoviny, T.; Peischl, J.; Perring, A. E.; Richardson, M. S.; Ryerson, T. B.; Schwarz, J. P.; Warneke, C.; Welti, A.; Wisthaler, A.; Ziemba, L. D.; Murphy, D. M.

    2015-02-01

    Vertical profiles of submicron aerosol over the southeastern United States (SEUS) during the summertime from in situ aircraft-based measurements were used to construct aggregate profiles of chemical, microphysical, and optical properties. Shallow cumulus convection was observed during many profiles. These conditions enhance vertical transport of trace gases and aerosol and create a cloudy transition layer on top of the sub-cloud mixed layer. The trace gas and aerosol concentrations in the transition layer were modeled as a mixture with contributions from the mixed layer below and the free troposphere above. The amount of vertical mixing, or entrainment of air from the free troposphere, was quantified using the observed mixing ratio of carbon monoxide (CO). Although the median aerosol mass, extinction, and volume decreased with altitude in the transition layer, they were ~10% larger than expected from vertical mixing alone. This enhancement was likely due to secondary aerosol formation in the transition layer. Although the transition layer enhancements of the particulate sulfate and organic aerosol (OA) were both similar in magnitude, only the enhancement of sulfate was statistically significant. The column integrated extinction, or aerosol optical depth (AOD), was calculated for each individual profile, and the transition layer enhancement of extinction typically contributed less than 10% to the total AOD. Our measurements and analysis were motivated by two recent studies that have hypothesized an enhanced layer of secondary organic aerosol (SOA) aloft to explain the summertime enhancement of AOD (2-3 times greater than winter) over the southeastern United States. In contrast to this hypothesis, the modest enhancement we observed in the transition layer was not dominated by OA and was not a large fraction of the summertime AOD.

  11. The potential of LIRIC to validate the vertical profiles of the aerosol mass concentration estimated by an air quality model

    NASA Astrophysics Data System (ADS)

    Siomos, Nikolaos; Filoglou, Maria; Poupkou, Anastasia; Liora, Natalia; Dimopoulos, Spyros; Melas, Dimitris; Chaikovsky, Anatoli; Balis, Dimitris

    2015-04-01

    Vertical profiles of the aerosol mass concentration derived by a retrieval algorithm that uses combined sunphotometer and LIDAR data (LIRIC) were used in order to validate the mass concentration profiles estimated by the air quality model CAMx. LIDAR and CIMEL measurements of the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki were used for this validation.The aerosol mass concentration profiles of the fine and coarse mode derived by CAMx were compared with the respective profiles derived by the retrieval algorithm. For the coarse mode particles, forecasts of the Saharan dust transportation model BSC-DREAM8bV2 were also taken into account. Each of the retrieval algorithm's profiles were matched to the models' profile with the best agreement within a time window of four hours before and after the central measurement. OPAC, a software than can provide optical properties of aerosol mixtures, was also employed in order to calculate the angstrom exponent and the lidar ratio values for 355nm and 532nm for each of the model's profiles aiming in a comparison with the angstrom exponent and the lidar ratio values derived by the retrieval algorithm for each measurement. The comparisons between the fine mode aerosol concentration profiles resulted in a good agreement between CAMx and the retrieval algorithm, with the vertical mean bias error never exceeding 7 μgr/m3. Concerning the aerosol coarse mode concentration profiles both CAMx and BSC-DREAM8bV2 values are severely underestimated, although, in cases of Saharan dust transportation events there is an agreement between the profiles of BSC-DREAM8bV2 model and the retrieval algorithm.

  12. Vertical profiles of atmospheric fluorescent aerosols observed by a mutil-channel lidar spectrometer system

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Huang, J.; Zhou, T.; Sugimoto, N.; Bi, J.

    2015-12-01

    Zhongwei Huang1*, Jianping Huang1, Tian Zhou1, Nobuo Sugimoto2, Jianrong Bi1 and Jinsen Shi11Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, China. 2Atmospheric Environment Division, National Institutes for Environmental Studies, Tsukuba, Japan Email: huangzhongwei@lzu.edu.cn Abstract Atmospheric aerosols have a significant impact on regional and globe climate. The challenge in quantifying aerosol direct radiative forcing and aerosol-cloud interactions arises from large spatial and temporal heterogeneity of aerosol concentrations, compositions, sizes, shape and optical properties (IPCC, 2007). Lidar offers some remarkable advantages for determining the vertical structure of atmospheric aerosols and their related optical properties. To investigate the characterization of atmospheric aerosols (especially bioaerosols) with high spatial and temporal resolution, we developed a Raman/fluorescence/polarization lidar system employed a multi-channel spectrometer, with capabilities of providing measurements of Raman scattering and laser-induced fluorescence excitation at 355 nm from atmospheric aerosols. Meanwhile, the lidar system operated polarization measurements both at 355nm and 532nm wavelengths, aiming to obtain more information of aerosols. It employs a high power pulsed laser and a received telescope with 350mm diameter. The receiver could simultaneously detect a wide fluorescent spectrum about 178 nm with spectral resolution 5.7 nm, mainly including an F/3.7 Crossed Czerny-Turner spectrograph, a grating (1200 gr/mm) and a PMT array with 32 photocathode elements. Vertical structure of fluorescent aerosols in the atmosphere was observed by the developed lidar system at four sites across northwest China, during 2014 spring field observation that conducted by Lanzhou University. It has been proved that the developed lidar could detect the fluorescent aerosols with high temporal and

  13. In situ vertical profiles of aerosol extinction, mass, and composition over the southeast United States during SENEX and SEAC4RS: observations of a modest aerosol enhancement aloft

    NASA Astrophysics Data System (ADS)

    Wagner, N. L.; Brock, C. A.; Angevine, W. M.; Beyersdorf, A.; Campuzano-Jost, P.; Day, D.; de Gouw, J. A.; Diskin, G. S.; Gordon, T. D.; Graus, M. G.; Holloway, J. S.; Huey, G.; Jimenez, J. L.; Lack, D. A.; Liao, J.; Liu, X.; Markovic, M. Z.; Middlebrook, A. M.; Mikoviny, T.; Peischl, J.; Perring, A. E.; Richardson, M. S.; Ryerson, T. B.; Schwarz, J. P.; Warneke, C.; Welti, A.; Wisthaler, A.; Ziemba, L. D.; Murphy, D. M.

    2015-06-01

    Vertical profiles of submicron aerosol from in situ aircraft-based measurements were used to construct aggregate profiles of chemical, microphysical, and optical properties. These vertical profiles were collected over the southeastern United States (SEUS) during the summer of 2013 as part of two separate field studies: the Southeast Nexus (SENEX) study and the Study of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS). Shallow cumulus convection was observed during many profiles. These conditions enhance vertical transport of trace gases and aerosol and create a cloudy transition layer on top of the sub-cloud mixed layer. The trace gas and aerosol concentrations in the transition layer were modeled as a mixture with contributions from the mixed layer below and the free troposphere above. The amount of vertical mixing, or entrainment of air from the free troposphere, was quantified using the observed mixing ratio of carbon monoxide (CO). Although the median aerosol mass, extinction, and volume decreased with altitude in the transition layer, they were ~10 % larger than expected from vertical mixing alone. This enhancement was likely due to secondary aerosol formation in the transition layer. Although the transition layer enhancements of the particulate sulfate and organic aerosol (OA) were both similar in magnitude, only the enhancement of sulfate was statistically significant. The column integrated extinction, or aerosol optical depth (AOD), was calculated for each individual profile, and the transition layer enhancement of extinction typically contributed less than 10 % to the total AOD. Our measurements and analysis were motivated by two recent studies that have hypothesized an enhanced layer of secondary aerosol aloft to explain the summertime enhancement of AOD (2-3 times greater than winter) over the southeastern United States. The first study attributes the layer aloft to secondary organic aerosol (SOA) while

  14. Vertical profiles of aerosol and black carbon in the Arctic: a seasonal phenomenology along 2 years (2011-2012) of field campaigns

    NASA Astrophysics Data System (ADS)

    Ferrero, Luca; Cappelletti, David; Busetto, Maurizio; Mazzola, Mauro; Lupi, Angelo; Lanconelli, Christian; Becagli, Silvia; Traversi, Rita; Caiazzo, Laura; Giardi, Fabio; Moroni, Beatrice; Crocchianti, Stefano; Fierz, Martin; Močnik, Griša; Sangiorgi, Giorgia; Perrone, Maria G.; Maturilli, Marion; Vitale, Vito; Udisti, Roberto; Bolzacchini, Ezio

    2016-10-01

    We present results from a systematic study of vertical profiles of aerosol number size distribution and black carbon (BC) concentrations conducted in the Arctic, over Ny-Ålesund (Svalbard). The campaign lasted 2 years (2011-2012) and resulted in 200 vertical profiles measured by means of a tethered balloon (up to 1200 m a.g.l.) during the spring and summer seasons. In addition, chemical analysis of filter samples, aerosol size distribution and a full set of meteorological parameters were determined at ground. The collected experimental data allowed a classification of the vertical profiles into different typologies, which allowed us to describe the seasonal phenomenology of vertical aerosol properties in the Arctic. During spring, four main types of profiles were found and their behavior was related to the main aerosol and atmospheric dynamics occurring at the measuring site. Background conditions generated homogenous profiles. Transport events caused an increase of aerosol concentration with altitude. High Arctic haze pollution trapped below thermal inversions promoted a decrease of aerosol concentration with altitude. Finally, ground-based plumes of locally formed secondary aerosol determined profiles with decreasing aerosol concentration located at different altitude as a function of size. During the summer season, the impact from shipping caused aerosol and BC pollution plumes to be constrained close to the ground, indicating that increasing shipping emissions in the Arctic could bring anthropogenic aerosol and BC in the Arctic summer, affecting the climate.

  15. Vertical Profiles of Cloud Condensation Nuclei, Condensation Nuclei, Optical Aerosol, Aerosol Optical Properties, and Aerosol Volatility Measured from Balloons

    NASA Technical Reports Server (NTRS)

    Deshler, T.; Snider, J. R.; Vali, G.

    1998-01-01

    Under the support of this grant a balloon-borne gondola containing a variety of aerosol instruments was developed and flown from Laramie, Wyoming, (41 deg N, 105 deg W) and from Lauder, New Zealand (45 deg S, 170 deg E). The gondola includes instruments to measure the concentrations of condensation nuclei (CN), cloud condensation nuclei (CCN), optically detectable aerosol (OA.) (r greater than or equal to 0.15 - 2.0 microns), and optical scattering properties using a nephelometer (lambda = 530 microns). All instruments sampled from a common inlet which was heated to 40 C on ascent and to 160 C on descent. Flights with the CN counter, OA counter, and nephelometer began in July 1994. The CCN counter was added in November 1994, and the engineering problems were solved by June 1995. Since then the flights have included all four instruments, and were completed in January 1998. Altogether there were 20 flights from Laramie, approximately 5 per year, and 2 from Lauder. Of these there were one or more engineering problems on 6 of the flights from Laramie, hence the data are somewhat limited on those 6 flights, while a complete data set was obtained from the other 14 flights. Good CCN data are available from 12 of the Laramie flights. The two flights from Lauder in January 1998 were successful for all measurements. The results from these flights, and the development of the balloon-bome CCN counter have formed the basis for five conference presentations. The heated and unheated CN and OA measurements have been used to estimate the mass fraction of the aerosol volatile, while comparisons of the nephelometer measurements were used to estimate the light scattering, associated with the volatile aerosol. These estimates were calculated for 0.5 km averages of the ascent and descent data between 2.5 km and the tropopause, near 11.5 km.

  16. Seasonal variation of surface and vertical profile of aerosol properties over a tropical urban station Hyderabad, India

    NASA Astrophysics Data System (ADS)

    Sinha, P. R.; Manchanda, R. K.; Kaskaoutis, D. G.; Kumar, Y. B.; Sreenivasan, S.

    2013-01-01

    One year measurement of vertical profiles of volume backscatter and extinction coefficient, aerosol optical depth (AOD), mass concentration of black carbon (BC) and composite aerosol along with thermodynamic structure of the atmosphere has been carried out over an urban tropical location of Hyderabad(17.47°N, 78.58°E), India, during April 2009 to March 2010. The mean mixing layer height (MLH) exhibits large seasonality exceeding 4 km in pre-monsoon period whereas in winter it comes down to ~1.5 km with an annual mean value of 2.35 ± 1.02 km. Surface BC mass fraction (FBC) shows marked seasonal variation from winter (13 ± 1.9%), pre-monsoon (8.19 ± 2.16%), monsoon (7.3 ± 1.8%) to post-monsoon (11.8 ± 0.18%). The profiles of volume backscatter and extinction coefficients reveal presence of elevated aerosol layers from 2 to 4 km and strong oscillations during pre-monsoon (March-May) and monsoon (June-September) seasons, respectively, while in post-monsoon (October-November) and winter (December-February), the aerosols are well within the lower boundary layer and also exhibit a drastic decrease with increasing altitude. These elevated aerosol layers and vertical distribution appear to be closely linked to the thermodynamic structure of the atmosphere. The aerosol optical properties in conjunction with air mass back trajectory analysis indicate that the observed elevated aerosol layers during pre-monsoon and monsoon could contain significant fraction of coarse mode particles with a mix of dust and marine aerosols. Further analysis reveals that the aerosols within atmospheric boundary layer (ABL) dominate the column aerosol loading with ABL-AOD contributing to ~77.7 ± 17.0%, with significant seasonal variation from winter (86.2 ± 13.1%), pre-monsoon (76.6 ± 12.8%), monsoon (54.2 ± 15.6%) to post monsoon (80.8 ± 14.8%). Seasonal variation of ABL-AOD and BC mass fraction follows similar pattern in the ABL indicating that BC may be an important contributor to

  17. Polarimetric remote sensing in oxygen A and B bands: sensitivity study and information content analysis for vertical profile of aerosols

    NASA Astrophysics Data System (ADS)

    Ding, Shouguo; Wang, Jun; Xu, Xiaoguang

    2016-05-01

    Theoretical analysis is conducted to reveal the information content of aerosol vertical profile in space-borne measurements of the backscattered radiance and degree of linear polarization (DOLP) in oxygen (O2) A and B bands. Assuming a quasi-Gaussian shape for aerosol vertical profile characterized by peak height H and half width γ (at half maximum), the Unified Linearized Vector Radiative Transfer Model (UNL-VRTM) is used to simulate the Stokes four-vector elements of upwelling radiation at the top of atmosphere (TOA) and their Jacobians with respect to H and γ. Calculations for different aerosol types and different combinations of H and γ values show that the wide range of gas absorption optical depth in O2 A and B band enables the sensitivity of backscattered DOLP and radiance at TOA to the aerosol layer at different altitudes. Quantitatively, DOLP in O2 A and B bands is found to be more sensitive to H and γ than radiance, especially over the bright surfaces (with large visible reflectance). In many O2 absorption wavelengths, the degree of freedom of signal (DFS) for retrieving H (or γ) generally increases with H (and γ) and can be close to unity in many cases, assuming that the composite uncertainty from surface and aerosol scattering properties as well as measurements is less than 5 %. Further analysis demonstrates that DFS needed for simultaneous retrieval of H and γ can be obtained from a combined use of DOLP measurements at ˜ 10-100 O2 A and B absorption wavelengths (or channels), depending on the specific values of H. The higher the aerosol layer, the fewer number of channels for DOLP measurements in O2 A and B bands are needed for characterizing H and γ. Future hyperspectral measurements of DOLP in O2 A and B bands are needed to continue studying their potential and their combination with radiance and DOLP in atmospheric window channels for retrieving the vertical profiles of aerosols, especially highly scattering aerosols, over land.

  18. Evaluation of the aerosol vertical distribution in global aerosol models through comparison against CALIOP measurements: AeroCom phase II results: AEROSOL PROFILES IN AEROCOM II GCM

    SciTech Connect

    Koffi, Brigitte; Schulz, Michael; Bréon, François-Marie; Dentener, Frank; Steensen, Birthe Marie; Griesfeller, Jan; Winker, David; Bauer, Susanne E.; Bellouin, Nicolas; Berntsen, Terje; Bian, Huisheng; Chin, Mian; Diehl, Thomas; Easter, Richard; Ghan, Steven; Hauglustaine, Didier A.; Iversen, Trond; Kirkevåg, Alf; Liu, Xiaohong; Lohmann, Ulrike; Myhre, Gunnar; Rasch, Phil; Seland, Øyvind; Skeie, Ragnhild B.; Steenrod, Stephen D.; Stier, Philip; Tackett, Jason; Takemura, Toshihiko; Tsigaridis, Kostas; Vuolo, Maria Raffaella; Yoon, Jinho; Zhang, Kai

    2016-06-27

    The ability of eleven models in simulating the aerosol vertical distribution from regional to global scales, as part of the second phase of the AeroCom model inter-comparison initiative (AeroCom II) is assessed and compared to results of the first phase. The evaluation is performed using a global monthly gridded dataset of aerosol extinction profiles built on purpose from the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) Layer Product 3.01. Results over 12 sub-continental regions show that five models improved whereas three degraded in reproducing the Zα 0-6 km mean extinction height diagnostic, which is computed over the 0-6 km altitude range for each studied region and season. While the models’ performance remains highly variable, it has generally improved in terms of inter-regional diversity and seasonality. The biases in Zα 0-6 km have notably decreased in the U.S. and European industrial and downwind maritime regions, whereas the timing of the Zα 0-6 km peak season has improved for all but two models. However, most of the models now show a Zα 0-6 km underestimation over land, notably in the dust and biomass burning regions in Asia and Africa. At global scale, the AeroCom II models better reproduce the Zα 0-6 km latitudinal variability over ocean than over land. Hypotheses for the (changes in the) the performance of the individual models and for the inter-model diversity are discussed. We also provide an analysis of the CALIOP limitations and uncertainties that can contribute to the differences between the simulations and observations.

  19. How Well do State-of-the-Art Techniques Measuring the Vertical Profile of Tropospheric Aerosol Extinction Compare?

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Ferrare, R.; Flynn, C.; Elleman, R.; Covert, D.; Strawa, A.; Welton, E.; Turner, D.; Jonsson, H.; Redemann, J.; Eilers, J.; Ricci, K.; Hallar, A. G.; Clayton, M.; Michalsky, J.; Smirnov, A.; Holben, B.; Barnard, J.

    2006-01-01

    The recent Department of Energy Atmospheric Radiation Measurement (ARM) Aerosol Intensive Operations Period (AIOP, May 2003) yielded one of the best measurement sets obtained to date to assess our ability to measure the vertical profile of ambient aerosol extinction sigma(ep)(lambda) in the lower troposphere. During one month, a heavily instrumented aircraft with well-characterized aerosol sampling ability carrying well-proven and new aerosol instrumentation devoted most of the 60 available flight hours to flying vertical profiles over the heavily instrumented ARM Southern Great Plains (SGP) Climate Research Facility (CRF). This allowed us to compare vertical extinction profiles obtained from six different instruments: airborne Sun photometer (AATS-14), airborne nephelometer/absorption photometer, airborne cavity ring-down system, groundbased Raman lidar, and two ground-based elastic backscatter lidars. We find the in situ measured sigma(ep)(lambda) to be lower than the AATS-14 derived values. Bias differences are 0.002-0.004 Km!1 equivalent to 13-17% in the visible, or 45% in the near-infrared. On the other hand, we find that with respect to AATS-14, the lidar sigma(ep)(lambda) are higher: Bias differences are 0.004 Km(-1) (13%) and 0.007 Km(-1) (24%) for the two elastic backscatter lidars (MPLNET and MPLARM, lambda = 523 nm) and 0.029 Km(-1) (54%) for the Raman lidar (lambda = 355 nm). An unnoticed loss of sensitivity of the Raman lidar had occurred leading up to AIOP, and we expect better agreement from the recently restored system. Looking at the collective results from six field campaigns conducted since 1996, airborne in situ measurements of sigma(ep)(lambda) tend to be biased slightly low (17% at visible wavelengths) when compared to airborne Sun photometer sigma(ep)(lambda). On the other hand, sigma(ep)(lambda) values derived from lidars tend to have no or positive biases. From the bias differences we conclude that the typical systematic error associated

  20. Saharan Desert Dust Sources: New Insights Based on Aerosol Vertical Profiles Retrieved from Thermal Infrared Measurements by IASI

    NASA Astrophysics Data System (ADS)

    Vandenbussche, S.; Kumps, N.; Vandaele, A. C.; De Maziere, M.

    2015-11-01

    Desert dust is a major actor in the climate and one of the least characterized with respect to its radiative forcing, both direct and indirect. Studies of dust atmospheric load and sources are therefore of great scientific interest. In the last years, we have developed and improved a retrieval strategy to obtain desert dust aerosols vertical profiles, from thermal infrared measurements by IASI. This strategy has been used to process significant amount of IASI data above North Africa. This dataset allows a new insight in the study of Saharan desert dust sources: it provides twice a day, at interesting times considering the dust emission diurnal cycle, vertical profiles of desert dust (not only optical depth), making possible to distinguish local emissions from transported dust.

  1. The Potential of The Synergy of Sunphotometer and Lidar Data to Validate Vertical Profiles of The Aerosol Mass Concentration Estimated by An Air Quality Model

    NASA Astrophysics Data System (ADS)

    Siomos, N.; Filioglou, M.; Poupkou, A.; Liora, N.; Dimopoulos, S.; Melas, D.; Chaikovsky, A.; Balis, D. S.

    2016-06-01

    Vertical profiles of the aerosol mass concentration derived by the Lidar/Radiometer Inversion Code (LIRIC), that uses combined sunphotometer and lidar data, were used in order to validate the aerosol mass concentration profiles estimated by the air quality model CAMx. Lidar and CIMEL measurements performed at the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, Greece (40.5N, 22.9E) from the period 2013-2014 were used in this study.

  2. Influence of atmospheric parameters on vertical profiles and horizontal transport of aerosols generated in the surf zone

    NASA Astrophysics Data System (ADS)

    Kusmierczyk-Michulec, J.; Tedeschi, G.; Van Eijk, A. M. J.; Piazzola, J.

    2013-10-01

    The vertical and horizontal transport of aerosols generated over the surf zone is discussed. Experimental data were collected during the second campaign of the Surf Zone Aerosol Experiment that took place in Duck NC (USA) in November 2007. The Empirical Orthogonal Function (EOF) method was used to analyze the vertical concentration gradients, and allowed separating the surf aerosols from aerosols advected from elsewhere. The numerical Marine Aerosol Concentration Model (MACMod) supported the analysis by confirming that the concentration gradients are more pronounced under stable conditions and that aerosol plumes are then more confined to the surface. The model also confirmed the experimental observations made during two boat runs along the offshore wind vector that surf-generated aerosols are efficiently advected out to sea over several tens of kilometers.

  3. The CU Airborne MAX-DOAS instrument: ground based validation, and vertical profiling of aerosol extinction and trace gases

    NASA Astrophysics Data System (ADS)

    Baidar, S.; Oetjen, H.; Coburn, S.; Dix, B.; Ortega, I.; Sinreich, R.; Volkamer, R.

    2012-09-01

    The University of Colorado Airborne Multi Axis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument uses solar stray light remote sensing to detect and quantify multiple trace gases, including nitrogen dioxide (NO2), glyoxal (CHOCHO), formaldehyde (HCHO), water vapor (H2O), nitrous acid (HONO), iodine monoxide (IO), bromine monoxide (BrO), and oxygen dimers (O4) at multiple wavelengths (360 nm, 477 nm, 577 nm and 632 nm) simultaneously, and sensitively in the open atmosphere. The instrument is unique, in that it presents the first systematic implementation of MAX-DOAS on research aircraft, i.e. (1) includes measurements of solar stray light photons from nadir, zenith, and multiple elevation angles forward and below the plane by the same spectrometer/detector system, and (2) features a motion compensation system that decouples the telescope field of view (FOV) from aircraft movements in real-time (< 0.35° accuracy). Sets of solar stray light spectra collected from nadir to zenith scans provide some vertical profile information within 2 km above and below the aircraft altitude, and the vertical column density (VCD) below the aircraft is measured in nadir view. Maximum information about vertical profiles is derived simultaneously for trace gas concentrations and aerosol extinction coefficients over similar spatial scales and with a vertical resolution of typically 250 m during aircraft ascent/descent. The instrument is described, and data from flights over California during the CalNex and CARES air quality field campaigns is presented. Horizontal distributions of NO2 VCDs (below the aircraft) maps are sampled with typically 1 km resolution, and show good agreement with two ground based CU MAX-DOAS instruments (slope 0.95 ± 0.09, R2 = 0.86). As a case study vertical profiles of NO2, CHOCHO, HCHO, and H2O mixing ratios and aerosol extinction coefficients, ɛ, at 477nm calculated from O4 measurements from a low approach at Brackett airfield inside the

  4. Vertical microphysical profiles of convective clouds as a tool for obtaining aerosol cloud-mediated climate forcings

    SciTech Connect

    Rosenfeld, Daniel

    2015-12-23

    Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Developing and validating this methodology was possible thanks to the ASR/ARM measurements of CCN and vertical updraft profiles. Validation against ground-based CCN instruments at the ARM sites in Oklahoma, Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25º restricts the satellite coverage to ~25% of the world area in a single day. This methodology will likely allow overcoming the challenge of quantifying the aerosol indirect effect and facilitate a substantial reduction of the uncertainty in anthropogenic climate forcing.

  5. Seasonal variability of aerosol vertical profiles over east US and west Europe: GEOS-Chem/APM simulation and comparison with CALIPSO observations

    NASA Astrophysics Data System (ADS)

    Ma, Xiaoyan; Yu, Fangqun

    2014-04-01

    In this study, we employed 5 years (2007-2011) of the CALIPSO level-3 monthly aerosol extinction product to compare with the GEOS-Chem/APM simulations for the same time period over two major industrial regions (east US and west Europe). The objective is to understand which aerosol types or species significantly determine the vertical profiles by comparing the seasonal variability between the simulations and observations. Our study shows that the model successfully produces the magnitude of aerosol extinction, profile shape, and their seasonal variability observed by CALIPSO over both east US (EUS) and west Europe (WEU). The extinctions below 1 km make up 44-79% to the total, from either the model simulations or satellite retrievals, with larger percentages in winter seasons (62-79%) and smaller percentages in summer seasons (44-57%) associated with the strength of vertical transport. The shape of the vertical profiles has, therefore, a distinct seasonal variability, with a more like quasi-exponential shape in DJF (December, January, and February) and SON (September, October, and November) than in MAM (March, April, and May) and JJA (June, July, and August), which have been discerned from both measurements and simulations. Analysis of modeled aerosol species indicates that secondary particles (SP), containing sulfate, ammonia, nitrate, and secondary organic aerosols (SOAs), predominantly determine the total aerosol vertical profiles while black carbon (BC), primary organic carbon (OC), and sea salt (SS), only account for a small fraction and are also limited near the surface. Mineral dust (DS) contributes more to the total extinction over WEU than over EUS, particularly in MAM, a result of being adjacent to the North Africa desert. Secondary inorganic aerosol (SIA, i.e. sulfate, ammonia, and nitrate) contributes most of the total SP mass in DJF and SON while SOA is particularly important in MAM and JJA when the emissions from leafed plants are active. Our study also

  6. Vertical profile of elemental concentrations in aerosol particles in the Bermuda area during GCE/CASE/WATOX

    NASA Astrophysics Data System (ADS)

    Ennis, G.; Sievering, H.

    1990-06-01

    During the 1988 Global Change Expedition/Coordinated Air-Sea Experiment/Western Atlantic Ocean Experiment (GCE/CASE/WATOX) joint effort, research was conducted to determine elemental concentrations in atmospheric aerosol particles near Bermuda, to construct a three-level (15, 150, and 2600 m ASL) vertical profile of these concentrations, and to ascertain the source of the particles. Samples were collected by the NOAA King Air aircraft and NOAA ship Mt. Mitchell on July 24-28, 1988. Concentration determinations were made for 16 elements through the use of an X ray fluorescence instrument designed for analysis of small-mass samples. A layering effect was found; concentrations of several elements at 150 m were more than twice their respective concentrations at 15 m and 2600 m. Enrichment factors, V/Mn ratio, and correlations between concentrations suggest a Saharan mineral source, despite air mass back trajectories that show no direct continental input for up to 10 days prior to sample collection. Estimated total mineral aerosol concentrations at 15 m, 150 m, and 2600 m are 1.5, 4.1, and 2.1 μg m-3.

  7. Characteristics of aerosol size distribution and vertical backscattering coefficient profile during 2014 APEC in Beijing

    NASA Astrophysics Data System (ADS)

    Zhang, Jiaoshi; Chen, Zhenyi; Lu, Yihuai; Gui, Huaqiao; Liu, Jianguo; Liu, Wenqing; Wang, Jie; Yu, Tongzhu; Cheng, Yin; Chen, Yong; Ge, Baozhu; Fan, Yu; Luo, Xisheng

    2017-01-01

    During the 2014 Asia-Pacific Economic Cooperation (APEC) conference period, Beijing's air quality was greatly improved as a result of a series of tough emission control measures being implemented in Beijing and its surrounding provinces. However, a moderate haze occurred during the period of 4-5 November. In order to evaluate the emission control measures and study the formation mechanism of the haze, a comprehensive field observation based on a supersite and a lidar network was carried out from 25 October 2014 to 20 January 2015. By investigating the variations in aerosol number concentration and mean backscattering coefficient before, during and after the APEC period, it was found that number concentration of accumulation mode and coarse mode particles experienced the most significant decrease by 47% and 68%, and mean backscattering coefficient below 1 km decreased by 34% during the APEC period. Being characterized as "rapidly accumulating and rapidly dispersing", the moderate haze occurred during the APEC period was probably initiated by a wind direction change to south and an increase of wind speed to 4 m/s. Sulfur dioxide involved plume nucleation without growth in size as well as a burst of particles ranging between 100 and 300 nm were observed simultaneously during the haze episode. The elevation of sulfur dioxide concentration and particle number concentration was highly correlated with the southerly wind, signifying the contribution of regional transport. It was observed by the lidar network that the aerosol backscattering coefficient increased in sequence among three sites along the southwest pathway, suggesting that aerosols might be transported from the southwest to the northeast of Beijing with a speed of approximately 17 km/h, which agreed with the movement of air masses modeled by Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT). The dual-wavelength lidar (355 and 532 nm) observation suggested that transportation of fine particles

  8. Pi-MAX: a new parametrized algorithm to retrieve vertical profiles of trace gases and aerosols from MAX-DOAS measurements

    NASA Astrophysics Data System (ADS)

    Remmers, Julia; Beirle, Steffen; Doerner, Steffen; Wagner, Thomas

    2013-04-01

    Multi-Axis (MAX-) DOAS instruments observe scattered sunlight under various mostly slant elevation angles. From such observations information on tropospheric profiles of trace gases and aerosols can be retrieved. MAX-DOAS observations can be used to quantify emissions and to study chemical processes in the atmosphere. Measuring (horizontally and vertically) averaged concentrations the technique can be used as a link between in-situ and satellite measurements. Thus satellite observations of tropospheric trace gases can be validated. IMAX (Parametrized Inversion for MAX-DOAS measurements) is a parametrized method to retrieve vertical profiles of trace gases (such as H2O, NO2, HCHO, CHOCHO) and aerosols. No online calculations are necessary, since look-up tables (LUT) calculated with a Monte Carlo based radiative Transport Model are used. In this manner it is user-friendly, easy to distribute and applicable to every measurement location. The here shown measurements took place in the Maldives in March, 2012, during the CARDEX campaign. Simultaneous sun photometry-, Lidar- and UAV-measurements provide the possibility to validate the new algorithm. We present time series of profiles of trace gas concentrations and aerosol extinction We discuss the effects of clouds on the retrieved results.

  9. Vertical profiling of Asian dust with multi-wavelength aerosol depolarization Raman lidar in Gwangju, Korea during DRAGON

    NASA Astrophysics Data System (ADS)

    Shin, D.; Mueller, D.; Noh, Y.; Shin, S.; Kim, Y. J.

    2013-12-01

    The Distributed Regional Aerosol Gridded Observation Networks (DRAGON) campaign, which was carried out in Korea from March to May 2013, aimed at validating satellite remote sensing data of aerosol optical and microphysical parameters. Anthropogenic pollution and Asian dust from the East Asian Mainland prevailed over the Korean peninsula during the DRAGON campaign. Validation of the data products requires knowledge on the vertical distribution of aerosol pollution and the knowledge of aerosol types, e.g., urban haze and dust. For this purpose we operated a multi-wavelength aerosol depolarization Raman lidar on the campus of the Gwangju Institute of Science and Technology (GIST) in Gwangju, Korea (35.10° N, 126.53° E). The system provides us with particle backscatter coefficients at 355, 532 and 1064 nm, extinction coefficients at 355 and 532nm, and the linear particle depolarization ratio at 532nm. Two upgraded sun photometers of the Aerosol Robotic Network (AERONET) with improved capabilities for dust measurements were also deployed. In our contribution we will present optical properties of Asian dust on the basis of lidar and sun photometer observations. One sun photometer was equipped with a measurement channel at 1640 nm channel and the second sun photometer carried out polarization measurements. Data could be collected on thirty-eight days We analyzed the geometrical and optical properties of Asian dust on the basis of backward trajectories in order to identify the main source regions of the observed dust layers. The height resolved statistical analysis of the DRAGON dataset reveals that the geometrical depth of the Asian dust layers was between 1 km and 4 km in 72% of all cases. Geometrical depths above 4 km were found in 20% of all cases. We found geometrical depths of 10 km in 3.3% of all cases. The vertical distribution of the dust layers was typically located in two different heights. In 51.5% of the measurements we observed Asian dust between 4 and 11km

  10. Synergic estimation of columnar integrated aerosol properties and their vertical resolved profiles in respect to the scenarios of dust intrusions over Granada

    NASA Astrophysics Data System (ADS)

    Mandija, Florian; Guerrero-Rascado, Juan Luis; Lyamani, Hassan; Granados-Muñoz, María José; Alados-Arboledas, Lucas

    2016-11-01

    In this paper, we present a study of the columnar and vertically resolved aerosol optical properties over Granada (Spain) during dust events detected during July-August in the period 2012-2013. For this purpose, we classified the events according to their origins and pathways. The analyzed aerosol properties include; columnar aerosol optical properties like aerosol optical depth (AOD) and Angstrom exponent (AE), as well as the lidar products, like backscatter-related Angstrom exponent and linear particle depolarization ratio (LDPR). The lidar profiles are used for determination of the geometrical structure of dust layers and the aerosol optical parameters inside dust layers. There are identified 58 dusty days over Granada during the periods July-August, 2012-2013. In 71% of the dust, event analyzed the dust plume over Granada is located between 3000 and 4000 m a.g.l. Mean values of AOD500 according to the Atlantic and Mediterranean pathway were 0.28 ± 0.10 and 0.93 ± 0.17. Meanwhile, the mean values of AE440-870 were 0.57 ± 0.25 and 0.43 ± 0.20. Three region are identified as the main dust sources affecting the dust intrusions over Granada. Two principal pathways of air masses during dust intrusion over Granada were observed: through Atlantic (52.7%) and through Mediterranean (47.3%). Air masses which come through the Mediterranean present larger AOD and lower Angstrom exponent values than those air masses coming through Atlantic. Lidar measurements show different vertical distributions on particle backscatter coefficient, during different scenarios of dust intrusions. The lidar profiles indicate that average base and top heights of all dust during the investigation period were 2.1 ± 0.7 and 4.8 ± 0.9 km, and their center of mass and thickness were 3.3 ± 0.7 and 2.8 ± 1.0 km a.g.l. The AE355/532 profiles for the dust intrusions present some differences depending on the source regions and path followed by the dust. On the other hand, the profiles of LPDRat

  11. Characterizing the Vertical Profile of Aerosol Particle Extinction and Linear Depolarization over Southeast Asia and the Maritime Continent: The 2007-2009 View from CALIOP

    NASA Technical Reports Server (NTRS)

    Campbell, James R.; Reid, Jeffrey S.; Westphal, Douglas L.; Zhang, Jianglong; Tackett, Jason L.; Chew, Boon Ning; Welton, Ellsworth J.; Shimizu, Atsushi; Sugimoto, Nobuo; Aoki, Kazuma; Winker, David M.

    2012-01-01

    Vertical profiles of 0.532 µm aerosol particle extinction coefficient and linear volume depolarization ratio are described for Southeast Asia and the Maritime Continent. Quality-screened and cloud-cleared Version 3.01 Level 2 NASA Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) 5-km Aerosol Profile datasets are analyzed from 2007 to 2009. Numerical simulations from the U.S. Naval Aerosol Analysis and Predictive System (NAAPS), featuring two-dimensional variational assimilation of NASA Moderate Resolution Imaging Spectroradiometer and Multi-angle Imaging Spectro- Radiometer quality-assured datasets, combined with regional ground-based lidar measurements, are considered for assessing CALIOP retrieval performance, identifying bias, and evaluating regional representativeness. CALIOP retrievals of aerosol particle extinction coefficient and aerosol optical depth (AOD) are high over land and low over open waters relative to NAAPS (0.412/0.312 over land for all data points inclusive, 0.310/0.235 when the per bin average is used and each is treated as single data points; 0.102/0.151 and 0.086/0.124, respectively, over ocean). Regional means, however, are very similar (0.180/0.193 for all data points and 0.155/0.159 when averaged per normalized bin), as the two factors offset one another. The land/ocean offset is investigated, and discrepancies attributed to interpretation of particle composition and a-priori assignment of the extinction-to-backscatter ratio ("lidar ratio") necessary for retrieving the extinction coefficient from CALIOP signals. Over land, NAAPS indicates more dust present than CALIOP algorithms are identifying, indicating a likely assignment of a higher lidar ratio representative of more absorptive particles. NAAPS resolvesmore smoke overwater than identified with CALIOP, indicating likely usage of a lidar ratio characteristic of less absorptive particles to be applied that biases low AOD there. Over open waters except within the Bay of Bengal

  12. Characterizing the vertical profile of aerosol particle extinction and linear depolarization over Southeast Asia and the Maritime Continent: The 2007-2009 view from CALIOP

    NASA Astrophysics Data System (ADS)

    Campbell, James R.; Reid, Jeffrey S.; Westphal, Douglas L.; Zhang, Jianglong; Tackett, Jason L.; Chew, Boon Ning; Welton, Ellsworth J.; Shimizu, Atsushi; Sugimoto, Nobuo; Aoki, Kazuma; Winker, David M.

    2013-03-01

    Vertical profiles of 0.532 μm aerosol particle extinction coefficient and linear volume depolarization ratio are described for Southeast Asia and the Maritime Continent. Quality-screened and cloud-cleared Version 3.01 Level 2 NASA Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) 5-km Aerosol Profile datasets are analyzed from 2007 to 2009. Numerical simulations from the U.S. Naval Aerosol Analysis and Predictive System (NAAPS), featuring two-dimensional variational assimilation of NASA Moderate Resolution Imaging Spectroradiometer and Multi-angle Imaging SpectroRadiometer quality-assured datasets, combined with regional ground-based lidar measurements, are considered for assessing CALIOP retrieval performance, identifying bias, and evaluating regional representativeness. CALIOP retrievals of aerosol particle extinction coefficient and aerosol optical depth (AOD) are high over land and low over open waters relative to NAAPS (0.412/0.312 over land for all data points inclusive, 0.310/0.235 when the per bin average is used and each is treated as single data points; 0.102/0.151 and 0.086/0.124, respectively, over ocean). Regional means, however, are very similar (0.180/0.193 for all data points and 0.155/0.159 when averaged per normalized bin), as the two factors offset one another. The land/ocean offset is investigated, and discrepancies attributed to interpretation of particle composition and a-priori assignment of the extinction-to-backscatter ratio (“lidar ratio”) necessary for retrieving the extinction coefficient from CALIOP signals. Over land, NAAPS indicates more dust present than CALIOP algorithms are identifying, indicating a likely assignment of a higher lidar ratio representative of more absorptive particles. NAAPS resolves more smoke over water than identified with CALIOP, indicating likely usage of a lidar ratio characteristic of less absorptive particles to be applied that biases low AOD there. Over open waters except within the Bay of

  13. Continental pollution in the western Mediterranean basin: vertical profiles of aerosol and trace gases measured over the sea during TRAQA 2012 and SAFMED 2013

    NASA Astrophysics Data System (ADS)

    Di Biagio, C.; Doppler, L.; Gaimoz, C.; Grand, N.; Ancellet, G.; Raut, J.-C.; Beekmann, M.; Borbon, A.; Sartelet, K.; Attié, J.-L.; Ravetta, F.; Formenti, P.

    2015-08-01

    In this study we present airborne observations of aerosol and trace gases obtained over the sea in the western Mediterranean basin during the TRAQA (TRansport and Air QuAlity) and SAFMED (Secondary Aerosol Formation in the MEDiterranean) campaigns in summer 2012 and 2013. A total of 23 vertical profiles were measured up to 5000 m above sea level over an extended area (40-45° N and 2° W-12° E) including the Gulf of Genoa, southern France, the Gulf of Lion, and the Spanish coast. During TRAQA and SAFMED the study area experienced a wide range of meteorological conditions which favoured pollution export from different sources located around the basin. Also, several events of dust outflows were measured during the campaigns. Observations from the present study show that continental pollution largely affects the western Mediterranean both close to coastal regions and in the open sea as far as ~ 250 km from the coastline. The measured aerosol scattering coefficient varies between ~ 20 and 120 Mm-1, while carbon monoxide (CO) and ozone (O3) mixing ratios are in the range of 60-165 and 30-85 ppbv, respectively. Pollution reaches 3000-4000 m in altitude and presents a very complex and highly stratified structure characterized by fresh and aged layers both in the boundary layer and in the free troposphere. Within pollution plumes the measured particle concentration in the Aitken (0.004-0.1 μm) and accumulation (0.1-1.0 μm) modes is between ~ 30 and 5000-6000 scm-3 (standard cm-3), which is comparable to the aerosol concentration measured in continental areas under pollution conditions. Additionally, our measurements indicate the presence of highly concentrated Aitken layers (10 000-15 000 scm-3) observed both close to the surface and in the free troposphere, possibly linked to the influence of new particle formation (NPF) episodes over the basin.

  14. Continental pollution in the Western Mediterranean Basin: vertical profiles of aerosol and trace gases measured over the sea during TRAQA 2012 and SAFMED 2013

    NASA Astrophysics Data System (ADS)

    Di Biagio, C.; Doppler, L.; Gaimoz, C.; Grand, N.; Ancellet, G.; Raut, J.-C.; Beekmann, M.; Borbon, A.; Sartelet, K.; Attié, J.-L.; Ravetta, F.; Formenti, P.

    2015-03-01

    In this study we present airborne observations of aerosol and trace gases obtained over the sea in the Western Mediterranean Basin during the TRAQA (TRansport and Air QuAlity) and SAFMED (Secondary Aerosol Formation in the MEDiterranean) campaigns in summers 2012 and 2013. A total of 23 vertical profiles were measured up to 5000 m a.s.l. over an extended area (40-45° N latitude and 2° W-12° E longitude) including the Gulf of Genoa, Southern France, the Gulf of Lion, and the Spanish coast. TRAQA and SAFMED successfully measured a wide range of meteorological conditions which favoured the pollution export from different sources located around the basin. Also, several events of dust outflows were measured during the campaigns. Observations from the present study indicate that continental pollution largely affects the Western Mediterranean both close to coastal regions and in the open sea as far as ~250 km from the coastline. Aerosol layers not specifically linked with Saharan dust outflows are distributed ubiquitously which indicates quite elevated levels of background pollution throughout the Western Basin. The measured aerosol scattering coefficient varies between ~20 and 120 M m-1, while carbon monoxide (CO) and ozone (O3) mixing ratios are in the range of 60-170 and 30-85 ppbv, respectively. Pollution reaches 3000-4000 m in altitude and presents a very complex and highly stratified structure characterized by fresh and aged layers both in the boundary layer and in the free troposphere. Within pollution plumes the measured particle concentration in the Aitken (0.004-0.1 μm) and accumulation (0.1-1.0 μm) modes is between ˜ 100 and 5000-6000 s cm-3 (standard cm-3), which is comparable to the aerosol concentration measured in continental urban areas. Additionally, our measurements indicate the presence of highly concentrated Aitken layers (10 000-15 000 s cm-3) observed both close to the surface and in the free troposphere, possibly linked to the influence of new

  15. Inter-comparison of MAX-DOAS Retrieved Vertical Profiles of Aerosol Extinction, SO2 and NO2 in the Alberta Oil Sands with LIDAR Data and GEM-MACH Air Quality Model.

    NASA Astrophysics Data System (ADS)

    Davis, Zoe; Friess, Udo; Strawbridge, Kevin; Whiteway, James; Aggarwal, Monika; Makar, Paul; Li, Shao-Meng; O'Brien, Jason; Baray, Sabour; Schnitzler, Elijah; Olfert, Jason S.; Osthoff, Hans D.; Lobo, Akshay; McLaren, Robert

    2016-04-01

    Understanding industrial emissions of trace gas pollutants in the Alberta oil sands is essential to maintaining air quality standards and informing public policy. Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of trace gases can improve knowledge of pollutant levels, vertical distribution and chemical transformation. During an intensive air measurement campaign to study emissions, transport, transformation and deposition of oil sands air pollutants from August to September of 2013, a MAX-DOAS instrument was deployed at a site north of Fort McMurray, Alberta to determine the vertical profiles of aerosol extinction, NO2 and SO2 through retrieval from the MAX-DOAS spectral measurements using an optimal estimation method. The large complement of data collected from multiple instruments deployed during this field campaign provides a unique opportunity to validate and characterize the performance of the MAX-DOAS vertical profile retrievals. Aerosol extinction profiles determined from two Light Detection and Ranging (LIDAR) instruments, one collocated and the other on a Twin Otter aircraft that flew over the site during the study, will be compared to the MAX-DOAS aerosol extinction profile retrievals. Vertical profiles of NO2 and SO2 retrieved from the MAX-DOAS measurements will be further compared with the composite vertical profiles measured from the flights of a second aircraft, the NRC-Convair 580, over the field site during the same measurement period. Finally, the MAX-DOAS retrieved tropospheric vertical column densities (VCDs) of SO2 and NO2 will be compared to the predicted VCDs from Environment and Climate Change Canada's Global Environmental Multi-scale - Modelling Air quality and Chemistry (GEM-MACH) air quality model over the grid cell containing the field site. Emission estimates of SO2 from the major oil mining facility Syncrude Mildred Lake using the MAX-DOAS VCD results, validated through the detailed characterization above

  16. Offset vertical radar profiling

    USGS Publications Warehouse

    Witten, A.; Lane, J.

    2003-01-01

    Diffraction tomography imaging was applied to VRP data acquired by vertically moving a receiving antenna in a number of wells. This procedure simulated a vertical downhole receiver array. Similarly, a transmitting antenna was sequentially moved along a series of radial lines extending outward from the receiver wells. This provided a sequence of multistatic data sets and, from each data set, a two-dimensional vertical cross-sectional image of spatial variations in wave speed was reconstructed.

  17. Parameter sensitivity study of Arctic aerosol vertical distribution in CAM5

    NASA Astrophysics Data System (ADS)

    Jiao, C.; Flanner, M.

    2015-12-01

    Arctic surface temperature response to light-absorbing aerosols (black carbon, brown carbon and dust) depends strongly on their vertical distributions. Improving model simulations of three dimensional aerosol fields in the remote Arctic region will therefore lead to improved projections of the climate change caused by aerosol emissions. In this study, we investigate how different physical parameterizations in the Community Atmosphere Model version 5 (CAM5) influence the simulated vertical distribution of Arctic aerosols. We design experiments to test the sensitivity of the simulated aerosol fields to perturbations of selected aerosol process-related parameters in the Modal Aerosol Module with seven lognormal modes (MAM7), such as those govern aerosol aging, in-cloud and below-cloud scavenging, aerosol hygroscopicity and so on. The simulations are compared with observed aerosol vertical distributions and total optical depth to assess model performance and quantify uncertainties associated with these model parameterizations. Observations applied here include Arctic aircraft measurements of black carbon and sulfate vertical profiles, along with Aerosol Robotic Network (AERONET) optical depth measurements. We also assess the utility of using High Spectral Resolution Lidar (HSRL) measurements from the ARM Barrow site to infer vertical profiles of aerosol extinction. The sensitivity study explored here will provide guidance for optimizing global aerosol simulations.

  18. Vertical Profiling of Air Pollution at RAPCD

    NASA Technical Reports Server (NTRS)

    Newchurch, Michael J.; Fuller, Kirk A.; Bowdle, David A.; Johnson, Steven; Knupp, Kevin; Gillani, Noor; Biazar, Arastoo; Mcnider, Richard T.; Burris, John

    2004-01-01

    The interaction between local and regional pollution levels occurs at the interface of the Planetary Boundary Layer and the Free Troposphere. Measuring the vertical distribution of ozone, aerosols, and winds with high temporal and vertical resolution is essential to diagnose the nature of this interchange and ultimately for accurately forecasting ozone and aerosol pollution levels. The Regional Atmospheric Profiling Center for Discovery, RAPCD, was built and instrumented to address this critical issue. The ozone W DIAL lidar, Nd:YAG aerosol lidar, and 2.1 micron Doppler wind lidar, along with balloon- borne ECC ozonesondes form the core of the W C D instrumentation for addressing this problem. Instrumentation in the associated Mobile Integrated Profiling (MIPS) laboratory includes 91 5Mhz profiler, sodar, and ceilometer. The collocated Applied particle Optics and Radiometry (ApOR) laboratory hosts an FTIR along with MOUDI and optical particle counters. With MODELS-3 analysis by colleagues in the National Space Science and Technology Center on the UAH campus and the co- located National Weather Service Forecasting Office in Huntsville, AL we are developing a unique facility for advancing the state of the science of pollution forecasting.

  19. Verification of the naval oceanic vertical aerosol model during FIRE

    NASA Technical Reports Server (NTRS)

    Davidson, K. L.; Deleeuw, G.; Gathman, S. G.; Jensen, D. R.

    1990-01-01

    The value of Naval Oceanic Vertical Aerosol Model (NOVAM) is illustrated for estimating the non-uniform and non-logarithmic extinction profiles, based on a severe test involving conditions close to and beyond the limits of applicability of NOVAM. A more comprehensive evaluation of NOVAM from the FIRE data is presented, which includes a clear-air case. For further evaluation more data are required on the vertical structure of the extinction in the marine atmospheric boundary layer (MABL), preferably for different meteorological conditions and in different geographic areas (e.g., ASTEX).

  20. Comparison of Aerosol Classification from Airborne High Spectral Resolution Lidar and the CALIPSO Vertical Feature Mask

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Ferrare, R. A.; Omar, A. H.; Hostetler, C. A.; Hair, J. W.; Rogers, R.; Obland, M. D.; Butler, C. F.; Cook, A. L.; Harper, D. B.

    2012-12-01

    The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL-1) on the NASA B200 aircraft has acquired large datasets of aerosol extinction (532nm), backscatter (532 and 1064nm), and depolarization (532 and 1064nm) profiles during 349 science flights in 19 field missions across North America since 2006. The extinction-to-backscatter ratio ("lidar ratio"), aerosol depolarization ratios, and backscatter color ratio measurements from HSRL-1 are scale-invariant parameters that depend on aerosol type but not concentration. These four aerosol intensive parameters are combined to qualitatively classify HSRL aerosol measurements into eight separate composition types. The classification methodology uses models formed from "training cases" with known aerosol type. The remaining measurements are then compared with these models using the Mahalanobis distance. Aerosol products from the CALIPSO satellite include aerosol type information as well, which is used as input to the CALIPSO aerosol retrieval. CALIPSO aerosol types are inferred using a mix of aerosol loading-dependent parameters, estimated aerosol depolarization, and location, altitude, and surface type information. The HSRL instrument flies beneath the CALIPSO satellite orbit track, presenting the opportunity for comparisons between the HSRL aerosol typing and the CALIPSO Vertical Feature Mask Aerosol Subtype product, giving insight into the performance of the CALIPSO aerosol type algorithm. We find that the aerosol classification from the two instruments frequently agree for marine aerosols and pure dust, and somewhat less frequently for pollution and smoke. In addition, the comparison suggests that the CALIPSO polluted dust type is overly inclusive, encompassing cases of dust combined with marine aerosol as well as cases without much evidence of dust. Qualitative classification of aerosol type combined with quantitative profile measurements of aerosol backscatter and extinction has many useful

  1. Vertical Profiles of Light Scattering, Light Absorption, and Single Scattering Albedo during the Dry, Biomass Burning Season in Southern Africa and Comparisons of In Situ and Remote Sensing Measurements of Aerosol Optical Depths

    NASA Technical Reports Server (NTRS)

    Magi, Brian I.; Hobbs, Peter V.; Schmid, Beat; Redermann, Jens

    2003-01-01

    Airborne in situ measurements of vertical profiles of aerosol light scattering, light absorption, and single scattering albedo (omega (sub 0)) are presented for a number of locations in southern Africa during the dry, biomass burning season. Features of the profiles include haze layers, clean air slots, and marked decreases in light scattering in passing from the boundary layer into the free troposphere. Frequency distributions of omega (sub 0) reflect the strong influence of smoke from biomass burning. For example, during a period when heavy smoke was advected into the region from the north, the mean value of omega (sub 0) in the boundary layer was 0.81 +/- 0.02 compared to 0.89 +/- 0.03 prior to this intrusion. Comparisons of layer aerosol optical depths derived from the in situ measurements with those measured by a Sun photometer aboard the aircraft show excellent agreement.

  2. Variability of aerosol vertical distribution in the Sahel

    NASA Astrophysics Data System (ADS)

    Cavalieri, O.; Cairo, F.; Fierli, F.; di Donfrancesco, G.; Snels, M.; Viterbini, M.; Cardillo, F.; Chatenet, B.; Formenti, P.; Marticorena, B.; Rajot, J. L.

    2010-12-01

    months, the entire Sahelian region is under the influence of Saharan dust aerosols: the air masses in low levels arrive from West Africa crossing the Sahara desert or from the Southern Hemisphere crossing the Guinea Gulf while in the upper layers air masses still originate from North, North-East. The maximum of the desert dust activity is observed in this period which is characterized by large AOD (above 0.2) and backscattering values. It also corresponds to a maximum in the extension of the aerosol vertical distribution (up to 6 km of altitude). In correspondence, a progressive cleaning up of the lowermost layers of the atmosphere is occurring, especially evident in the Banizoumbou and Cinzana sites. Summer is in fact characterized by extensive and fast convective phenomena. Lidar profiles show at times large dust events loading the atmosphere with aerosol from the ground up to 6 km of altitude. These events are characterized by large total attenuated backscattering values, and alternate with very clear profiles, sometimes separated by only a few hours, indicative of fast removal processes occurring, likely due to intense convective and rain activity. The inter-annual variability in the three year monitoring period is not very significant. An analysis of the aerosol transport pathways, aiming at detecting the main source regions, revealed that air originated from the Saharan desert is present all year long and it is observed in the lower levels of the atmosphere at the beginning and at the end of the year. In the central part of the year it extends upward and the lower levels are less affected by air masses from Saharan desert when the monsoon flow carries air from the Guinea Gulf and the Southern Hemisphere inland.

  3. Profiling Transboundary Aerosols over Taiwan and Assessing Their Radiative Effects

    NASA Technical Reports Server (NTRS)

    Wang, Sheng-Hsiang; Lin, Neng-Huei; Chou, Ming-Dah; Tsay, Si-Chee; Welton, Ellsworth J.; Hsu, N. Christina; Giles, David M.; Liu, Gin-Rong; Holben, Brent N.

    2010-01-01

    A synergistic process was developed to study the vertical distributions of aerosol optical properties and their effects on solar heating using data retrieved from ground-based radiation measurements and radiative transfer simulations. Continuous MPLNET and AERONET observations were made at a rural site in northern Taiwan from 2005 to 2007. The aerosol vertical extinction profiles retrieved from ground-based lidar measurements were categorized into near-surface, mixed, and two-layer transport types, representing 76% of all cases. Fine-mode (Angstrom exponent, alpha, approx.1.4) and moderate-absorbing aerosols (columnar single-scattering albedo approx.0.93, asymmetry factor approx.0.73 at 440 nm wavelength) dominated in this region. The column-integrated aerosol optical thickness at 500 nm (tau(sub 500nm)) ranges from 0.1 to 0.6 for the near-surface transport type, but can be doubled in the presence of upper-layer aerosol transport. We utilize aerosol radiative efficiency (ARE; the impact on solar radiation per unit change of tau(sub 500nm)) to quantify the radiative effects due to different vertical distributions of aerosols. Our results show that the ARE at the top-of-atmosphere (-23 W/ sq m) is weakly sensitive to aerosol vertical distributions confined in the lower troposphere. On the other hand, values of the ARE at the surface are -44.3, -40.6 and -39.7 W/sq m 38 for near-surface, mixed, and two-layer transport types, respectively. Further analyses show that the impact of aerosols on the vertical profile of solar heating is larger for the near-surface transport type than that of two-layer transport type. The impacts of aerosol on the surface radiation and the solar heating profiles have implications for the stability and convection in the lower troposphere.

  4. Measurement of the Vertical Distribution of Aerosol by Globally Distributed MP Lidar Network Sites

    NASA Technical Reports Server (NTRS)

    Spinhirne, James; Welton, Judd; Campbell, James; Starr, David OC. (Technical Monitor)

    2001-01-01

    The global distribution of aerosol has an important influence on climate through the scattering and absorption of shortwave radiation and through modification of cloud optical properties. Current satellite and other data already provide a great amount of information on aerosol distribution. However there are critical parameters that can only be obtained by active optical profiling. For aerosol, no passive technique can adequately resolve the height profile of aerosol. The aerosol height distribution is required for any model for aerosol transport and the height resolved radiative heating/cooling effect of aerosol. The Geoscience Laser Altimeter System (GLAS) is an orbital lidar to be launched by 2002. GLAS will provide global measurements of the height distribution of aerosol. The sampling will be limited by nadir only coverage. There is a need for local sites to address sampling, and accuracy factors. Full time measurements of the vertical distribution of aerosol are now being acquired at a number of globally distributed MP (micro pulse) lidar sites. The MP lidar systems provide profiling of all significant cloud and aerosol to the limit of signal attenuation from compact, eye safe instruments. There are currently six sites in operation and over a dozen planned. At all sites there are a complement of passive aerosol and radiation measurements supporting the lidar data. Four of the installations are at Atmospheric Radiation Measurement program sites. The aerosol measurements, retrievals and data products from the network sites will be discussed. The current and planned application of data to supplement satellite aerosol measurements is covered.

  5. Black Carbon Vertical Profiles Strongly Affect Its Radiative Forcing Uncertainty

    NASA Technical Reports Server (NTRS)

    Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, S.; Berntsen, T. K.; Bian, H.; Bellouin, N.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kinne, S.; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2013-01-01

    The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

  6. Black Carbon Vertical Profiles Strongly Affect its Radiative Forcing Uncertainty

    SciTech Connect

    Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, Susanne E.; Berntsen, T.; Bian, Huisheng; Bellouin, N.; Diehl, T.; Easter, Richard C.; Ghan, Steven J.; Iversen, T.; Kinne, Stefan; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, Xiaohong; Penner, Joyce E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, Kai

    2013-03-01

    The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

  7. Vertical profiles of aerosol black carbon in the atmospheric boundary layer over a tropical coastal station: Perturbations during an annular solar eclipse

    NASA Astrophysics Data System (ADS)

    Babu, S. Suresh; Sreekanth, V.; Moorthy, K. Krishna; Mohan, Mannil; Kirankumar, N. V. P.; Subrahamanyam, D. Bala; Gogoi, Mukunda M.; Kompalli, Sobhan Kumar; Beegum, Naseema; Chaubey, Jai Prakash; Kumar, V. H. Arun; Manchanda, Ravi K.

    2011-03-01

    Altitude profiles of aerosol black carbon (BC) in the atmospheric boundary layer (ABL) over a tropical coastal station, Trivandrum have been examined on two days using an aethalometer attached to a tethered balloon. One of these days (15th January, 2010) coincided with a (annular) solar eclipse, the longest of this century at this location, commenced at 11:05 local time and ended by 15:05, lasting for 7 min and 15 s (from 13:10:42), with its maximum contact occurring at ~ 13:14 IST with ~ 92% annularity, thereby providing an opportunity to understand the eclipse induced perturbations. Concurrent measurements of the ABL parameters such as air temperature, relative humidity and pressure were also made on these days to describe the response of the ABL to the eclipse. BC profiles, in general, depicted similar features up to an altitude of ~ 200 m on the eclipse day and control day, above which it differed conspicuously with profiles on eclipse day showing increasingly lower concentration as we moved to higher altitudes. Examination of the meteorological profiles showed that the altitude of maximum convection rapidly fell down during the eclipse period compared to that on control day indicating a rather shallow convection on eclipse day. Comparison of diurnal variations of BC at the surface level showed that the rate of decrease in BC during daytime on the eclipse day was smaller than that on the control day due to the reduced convection, shallow ABL and consequent reduction in the ventilation coefficient. Moreover the time of the nocturnal increase has advanced by ~ 1:30 h on the eclipse day, occurred at around 19:30 IST in contrast to all the other days of January 2010, where this increase usually occur well after 20:30 IST, with a mean value of 21:00 IST. This is attributed to the weak sea-breeze penetration during the eclipse day, which led to an early onset of the land breeze.

  8. Intercomparison of aerosol extinction profiles retrieved from MAX-DOAS measurements

    NASA Astrophysics Data System (ADS)

    Frieß, U.; Klein Baltink, H.; Beirle, S.; Clémer, K.; Hendrick, F.; Henzing, B.; Irie, H.; de Leeuw, G.; Li, A.; Moerman, M. M.; van Roozendael, M.; Shaiganfar, R.; Wagner, T.; Wang, Y.; Xie, P.; Yilmaz, S.; Zieger, P.

    2016-07-01

    A first direct intercomparison of aerosol vertical profiles from Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations, performed during the Cabauw Intercomparison Campaign of Nitrogen Dioxide measuring Instruments (CINDI) in summer 2009, is presented. Five out of 14 participants of the CINDI campaign reported aerosol extinction profiles and aerosol optical thickness (AOT) as deduced from observations of differential slant column densities of the oxygen collision complex (O4) at different elevation angles. Aerosol extinction vertical profiles and AOT are compared to backscatter profiles from a ceilometer instrument and to sun photometer measurements, respectively. Furthermore, the near-surface aerosol extinction coefficient is compared to in situ measurements of a humidity-controlled nephelometer and dry aerosol absorption measurements. The participants of this intercomparison exercise use different approaches for the retrieval of aerosol information, including the retrieval of the full vertical profile using optimal estimation and a parametrised approach with a prescribed profile shape. Despite these large conceptual differences, and also differences in the wavelength of the observed O4 absorption band, good agreement in terms of the vertical structure of aerosols within the boundary layer is achieved between the aerosol extinction profiles retrieved by the different groups and the backscatter profiles observed by the ceilometer instrument. AOTs from MAX-DOAS and sun photometer show a good correlation (R>0.8), but all participants systematically underestimate the AOT. Substantial differences between the near-surface aerosol extinction from MAX-DOAS and from the humidified nephelometer remain largely unresolved.

  9. SAGE II aerosol correlative observations - Profile measurements

    NASA Technical Reports Server (NTRS)

    Osborn, M. T.; Rosen, J. M.; Mccormick, M. P.; Wang, Pi-Huan; Livinfston, J. M.

    1989-01-01

    Profiles of the aerosol extinction measurements from the Stratospheric Aerosol and Gas Experiment (SAGE) II are compared with profiles from five correlative experiments between November 1984 and July 1986. The correlative profiles were derived from six-channel dustsonde measurements and two-wavelength lidar backscatter data. The correlation between the dustsonde- and lidar-derived measurements and the SAGE II data is good, validating the SAGE II lower stratospheric aerosol extinction measurements.

  10. Dust layer profiling using an aerosol dropsonde

    NASA Astrophysics Data System (ADS)

    Ulanowski, Zbigniew; Kaye, Paul Henry; Hirst, Edwin; Wieser, Andreas; Stanley, Warren

    2015-04-01

    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 aerosol. The Centre for Atmospheric and Instrumentation Research at University of Hertfordshire develops light-scattering instruments for the characterization of aerosols 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 aerosols 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

  11. Characterizing the Vertical Distribution of Aerosols Over the ARM SGP Site

    SciTech Connect

    Richard Ferrare, Connor Flynn, David Turner

    2009-05-05

    This project focused on: 1) evaluating the performance of the DOE ARM SGP Raman lidar system in measuring profiles of water vapor and aerosols, and 2) the use of the Raman lidar measurements of aerosol and water vapor profiles for assessing the vertical distribution of aerosols and water vapor simulated by global transport models and examining diurnal variability of aerosols and water vapor. The highest aerosol extinction was generally observed close to the surface during the nighttime just prior to sunrise. The high values of aerosol extinction are most likely associated with increased scattering by hygroscopic aerosols, since the corresponding average relative humidity values were above 70%. After sunrise, relative humidity and aerosol extinction below 500 m decreased with the growth in the daytime convective boundary layer. The largest aerosol extinction for altitudes above 1 km occurred during the early afternoon most likely as a result of the increase in relative humidity. The water vapor mixing ratio profiles generally showed smaller variations with altitude between day and night. We also compared simultaneous measurements of relative humidity, aerosol extinction, and aerosol optical thickness derived from the ARM SGP Raman lidar and in situ instruments on board a small aircraft flown routinely over the ARM SGP site. In contrast, the differences between the CARL and IAP aerosol extinction measurements are considerably larger. Aerosol extinction derived from the IAP measurements is, on average, about 30-40% less than values derived from the Raman lidar. The reasons for this difference are not clear, but may be related to the corrections for supermicron scattering and relative humidity that were applied to the IAP data. The investigators on this project helped to set up a major field mission (2003 Aerosol IOP) over the DOE ARM SGP site. One of the goals of the mission was to further evaluate the aerosol and water vapor retrievals from this lidar system

  12. Vertical Distribution of Dust and Water Ice Aerosols from CRISM Limb-geometry Observations

    NASA Technical Reports Server (NTRS)

    Smith, Michael Doyle; Wolff, Michael J.; Clancy, Todd; Kleinbohl, Armin; Murchie, Scott L.

    2013-01-01

    [1] Near-infrared spectra taken in a limb-viewing geometry by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on board the Mars Reconnaissance Orbiter provide a useful tool for probing atmospheric structure. Specifically, the observed radiance as a function of wavelength and height above the limb enables the vertical distribution of both dust and water ice aerosols to be retrieved. More than a dozen sets of CRISM limb observations have been taken so far providing pole-to-pole cross sections, spanning more than a full Martian year. Radiative transfer modeling is used to model the observations taking into account multiple scattering from aerosols and the spherical geometry of the limb observations. Both dust and water ice vertical profiles often show a significant vertical structure for nearly all seasons and latitudes that is not consistent with the well-mixed or Conrath-v assumptions that have often been used in the past for describing aerosol vertical profiles for retrieval and modeling purposes. Significant variations are seen in the retrieved vertical profiles of dust and water ice aerosol as a function of season. Dust typically extends to higher altitudes (approx. 40-50km) during the perihelion season than during the aphelion season (<20km), and the Hellas region consistently shows more dust mixed to higher altitudes than other locations. Detached water ice clouds are common, and water ice aerosols are observed to cap the dust layer in all seasons.

  13. Electronic cigarette solutions and resultant aerosol profiles.

    PubMed

    Herrington, Jason S; Myers, Colton

    2015-10-30

    Electronic cigarettes (e-cigarettes) are growing in popularity exponentially. Despite their ever-growing acceptance, their aerosol has not been fully characterized. The current study focused on evaluating e-cigarette solutions and their resultant aerosol for potential differences. A simple sampling device was developed to draw e-cigarette aerosol into a multi-sorbent thermal desorption (TD) tube, which was then thermally extracted and analyzed via a gas chromatography (GC) mass spectrometry (GC-MS) method. This novel application provided detectable levels of over one hundred fifteen volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) from a single 40mL puff. The aerosol profiles from four commercially available e-cigarettes were compared to their respective solution profiles with the same GC-MS method. Solution profiles produced upwards of sixty four unidentified and identified (some only tentatively) constituents and aerosol profiles produced upwards of eighty two compounds. Results demonstrated distinct analyte profiles between liquid and aerosol samples. Most notably, formaldehyde, acetaldehyde, acrolein, and siloxanes were found in the aerosol profiles; however, these compounds were never present in the solutions. These results implicate the aerosolization process in the formation of compounds not found in solutions; have potential implications for human health; and stress the need for an emphasis on electronic cigarette aerosol testing.

  14. Recent Improvements to CALIOP Level 3 Aerosol Profile Product for Global 3-D Aerosol Extinction Characterization

    NASA Astrophysics Data System (ADS)

    Tackett, J. L.; Getzewich, B. J.; Winker, D. M.; Vaughan, M. A.

    2015-12-01

    With nine years of retrievals, the CALIOP level 3 aerosol profile product provides an unprecedented synopsis of aerosol extinction in three dimensions and the potential to quantify changes in aerosol distributions over time. The CALIOP level 3 aerosol profile product, initially released as a beta product in 2011, reports monthly averages of quality-screened aerosol extinction profiles on a uniform latitude/longitude grid for different cloud-cover scenarios, called "sky conditions". This presentation demonstrates improvements to the second version of the product which will be released in September 2015. The largest improvements are the new sky condition definitions which parse the atmosphere into "cloud-free" views accessible to passive remote sensors, "all-sky" views accessible to active remote sensors and "cloudy-sky" views for opaque and transparent clouds which were previously inaccessible to passive remote sensors. Taken together, the new sky conditions comprehensively summarize CALIOP aerosol extinction profiles for a broad range of scientific queries. In addition to dust-only extinction profiles, the new version will include polluted-dust and smoke-only extinction averages. A new method is adopted for averaging dust-only extinction profiles to reduce high biases which exist in the beta version of the level 3 aerosol profile product. This presentation justifies the new averaging methodology and demonstrates vertical profiles of dust and smoke extinction over Africa during the biomass burning season. Another crucial advancement demonstrated in this presentation is a new approach for computing monthly mean aerosol optical depth which removes low biases reported in the beta version - a scenario unique to lidar datasets.

  15. Vertical distribution of aerosol optical properties based on aircraft measurements over the Loess Plateau in China.

    PubMed

    Li, Junxia; Liu, Xingang; Yuan, Liang; Yin, Yan; Li, Zhanqing; Li, Peiren; Ren, Gang; Jin, Lijun; Li, Runjun; Dong, Zipeng; Li, Yiyu; Yang, Junmei

    2015-08-01

    Vertical distributions of aerosol optical properties based on aircraft measurements over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four flights were analyzed. The vertical distributions of aerosol optical properties including aerosol scattering coefficients (σsc), absorption coefficients (σab), Angström exponent (α), single scattering albedo (ω), backscattering ratio (βsc), aerosol mass scattering proficiency (Qsc) and aerosol surface scattering proficiency (Qsc(')) were obtained. The mean statistical values of σsc were 77.45 Mm(-1) (at 450 nm), 50.72 Mm(-1) (at 550n m), and 32.02 Mm(-1) (at 700 nm). The mean value of σab was 7.62 Mm(-1) (at 550 nm). The mean values of α, βsc and ω were 1.93, 0.15, and 0.91, respectively. Aerosol concentration decreased with altitude. Most effective diameters (ED) of aerosols were less than 0.8 μm. The vertical profiles of σsc,, α, βsc, Qsc and Qsc(') showed that the aerosol scattering properties at lower levels contributed the most to the total aerosol radiative forcing. Both α and βsc had relatively large values, suggesting that most aerosols in the observational region were small particles. The mean values of σsc, α, βsc, Qsc, Qsc('), σab and ω at different height ranges showed that most of the parameters decreased with altitude. The forty-eight hour backward trajectories of air masses during the observation days indicated that the majority of aerosols in the lower level contributed the most to the total aerosol loading, and most of these particles originated from local or regional pollution emissions.

  16. Comparison of Aerosol Classification Results from Airborne High Spectral Resolution Lidar (HSRL) Measurements and the Calipso Vertical Feature Mask

    NASA Technical Reports Server (NTRS)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Rogers, R. R.; Obland, M. D.; Butler, C. F.; Cook, A. L.; Harper, D. B.; Froyd, K. D.; Omar, A.

    2012-01-01

    Knowledge of the vertical profile, composition, concentration, and size of aerosols is required for assessing the direct impact of aerosols on radiation, the indirect effects of aerosols on clouds and precipitation, and attributing these effects to natural and anthropogenic aerosols. Because anthropogenic aerosols are predominantly submicrometer, fine mode fraction (FMF) retrievals from satellite have been used as a tool for deriving anthropogenic aerosols. Although column and profile satellite retrievals of FMF have been performed over the ocean, such retrievals have not yet been been done over land. Consequently, uncertainty in satellite estimates of the anthropogenic component of the aerosol direct radiative forcing is greatest over land, due in large part to uncertainties in the FMF. Satellite measurements have been used to detect and evaluate aerosol impacts on clouds; however, such efforts have been hampered by the difficulty in retrieving vertically-resolved cloud condensation nuclei (CCN) concentration, which is the most direct parameter linking aerosol and clouds. Recent studies have shown correlations between average satellite derived column aerosol optical thickness (AOT) and in situ measured CCN. However, these same studies, as well as others that use detailed airborne in situ measurements have noted that vertical variability of the aerosol distribution, impacts of relative humidity, and the presence of coarse mode aerosols such as dust introduce large uncertainties in such relations.

  17. Decoration of vertical graphene with aerosol nanoparticles for gas sensing

    NASA Astrophysics Data System (ADS)

    Cui, Shumao; Guo, Xiaoru; Ren, Ren; Zhou, Guihua; Chen, Junhong

    2015-08-01

    A facile method was demonstrated to decorate aerosol Ag nanoparticles onto vertical graphene surfaces using a mini-arc plasma reactor. The vertical graphene was directly grown on a sensor electrode using a plasma-enhanced chemical vapor deposition (PECVD) method. The aerosol Ag nanoparticles were synthesized by a simple vapor condensation process using a mini-arc plasma source. Then, the nanoparticles were assembled on the surface of vertical graphene through the assistance of an electric field. Based on our observation, nonagglomerated Ag nanoparticles formed in the gas phase and were assembled onto vertical graphene sheets. Nanohybrids of Ag nanoparticle-decorated vertical graphene were characterized for ammonia gas detection at room temperature. The vertical graphene served as the conductance channel, and the conductance change upon exposure to ammonia was used as the sensing signal. The sensing results show that Ag nanoparticles significantly improve the sensitivity, response time, and recovery time of the sensor.

  18. Aerosol profiling by calibrated ceilometer data

    NASA Astrophysics Data System (ADS)

    Geiß, Alexander; Wiegner, Matthias

    2015-04-01

    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 aerosols was investigated, to derive mixing layer heights 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 layer height by applying different techniques of averaging and pattern recognition. In this context, it is assumed that aerosols 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 layer heights (MLH), cloud cover, cloud heights 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 aerosol layers. For the latter applications backscatter coefficients are required. That means, a calibration of the ceilometers is mandatory.

  19. The Navy Oceanic Vertical Aerosol Model

    DTIC Science & Technology

    1993-12-01

    34windows" exist in the molecular absorption of the electromagnetic energy through which trans- missions in IR communication can take place. In these...the aerosol both scatters and absorbs electromagnetic energy . Of particular interest to the Navy is the role natural marine aerosols play within the...34 \\( )/ •dr12 This technique speeds up the calculations since the integrals can be calculated earlier and their values stored as numbers in a lookup table

  20. Aerosol vertical distribution characteristics over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Deng, Z. Q.; Han, Y. X.; Zhao, Q.; Li, J.

    2014-03-01

    The Stratospheric Aerosol and Gas Experiment II (SAGE II) aerosol products are widely used in climatic characteristic studies and stratospheric aerosol pattern research. Some SAGE II products, e.g., temperature, aerosol surface area density, 1020 nm aerosol extinction coefficient and dust storm frequency, from ground-based observations were analysed from 1984 to 2005. This analysis explored the time and spatial variations of tropospheric and stratospheric aerosols on the Tibet Plateau. The stratospheric aerosol extinction coefficient increased more than two orders of magnitude because of a large volcanic eruption. However, the tropospheric aerosol extinction coefficient decreased over the same period. Removing the volcanic eruption effect, the correlation coefficient for stratospheric AOD (Aerosol Optical Depth) and tropospheric AOD was 0.197. Moreover, the correlation coefficient for stratospheric AOD and dust storm frequency was 0.315. The maximum stratospheric AOD was attained in January, the same month as the tropospheric AOD, when the Qaidam Basin was the centre of low tropospheric AOD and the large mountains coincided with high stratospheric AOD. The vertical structure generated by westerly jet adjustment and the high altitude of the underlying surface of the Tibetan Plateau were important factors affecting winter stratospheric aerosols.

  1. Impact of aerosol vertical distribution on aerosol direct radiative effect and heating rate in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Pappas, Vasileios; Hatzianastassiou, Nikolaos; Matsoukas, Christos; Koras Carracca, Mario; Kinne, Stefan; Vardavas, Ilias

    2015-04-01

    It is now well-established that aerosols cause an overall cooling effect at the surface and a warming effect within the atmosphere. At the top of the atmosphere (TOA), both positive and negative forcing can be found, depending on a number of other factors, such as surface albedo and relative position of clouds and aerosols. Whilst aerosol surface cooling is important due to its relation with surface temperature and other bio-environmental reasons, atmospheric heating is of special interest as well having significant impacts on atmospheric dynamics, such as formation of clouds and subsequent precipitation. The actual position of aerosols and their altitude relative to clouds is of major importance as certain types of aerosol, such as black carbon (BC) above clouds can have a significant impact on planetary albedo. The vertical distribution of aerosols and clouds has recently drawn the attention of the aerosol community, because partially can account for the differences between simulated aerosol radiative forcing with various models, and therefore decrease the level of our uncertainty regarding aerosol forcing, which is one of our priorities set by IPCC. The vertical profiles of aerosol optical and physical properties have been studied by various research groups around the world, following different methodologies and using various indices in order to present the impact of aerosols on radiation on different altitudes above the surface. However, there is still variability between the published results as to the actual effect of aerosols on shortwave radiation and on heating rate within the atmosphere. This study uses vertical information on aerosols from the Max Planck Aerosol Climatology (MAC-v1) global dataset, which is a combination of model output with quality ground-based measurements, in order to provide useful insight into the vertical profile of atmospheric heating for the Mediterranean region. MAC-v1 and the science behind this aerosol dataset have already

  2. Retrieving the Vertical Structure of the Effective Aerosol Complex Index of Refraction from a Combination of Aerosol in Situ and Remote Sensing Measurements During TARFOX

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Turco, R. P.; Liou, K. N.; Russell, P. B.; Bergstrom, R. W.; Schmid, B.; Livingston, J. M.; Hobbs, P. V.; Hartley, W. S.; Ismail, S.; Ferrare, R. A.; Browell, E. V.

    2000-01-01

    The largest uncertainty in estimates of the effects of atmospheric aerosols on climate stems from uncertainties in the determination of their microphysical properties, including the aerosol complex index of refraction, which in turn determines their optical properties. A novel technique is used to estimate the aerosol complex index of refraction in distinct vertical layers from a combination of aerosol in situ size distribution and remote sensing measurements during the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX). In particular, aerosol backscatter measurements using the NASA Langley LASE (Lidar Atmospheric Sensing Experiment) instrument and in situ aerosol size distribution data are utilized to derive vertical profiles of the "effective" aerosol complex index of refraction at 815 nm (i.e., the refractive index that would provide the same backscatter signal in a forward calculation on the basis of the measured in situ particle size distributions for homogeneous, spherical aerosols). A sensitivity study shows that this method yields small errors in the retrieved aerosol refractive indices, provided the errors in the lidar-derived aerosol backscatter are less than 30% and random in nature. Absolute errors in the estimated aerosol refractive indices are generally less than 0.04 for the real part and can be as much as 0.042 for the imaginary part in the case of a 30% error in the lidar-derived aerosol backscatter. The measurements of aerosol optical depth from the NASA Ames Airborne Tracking Sunphotometer (AATS-6) are successfully incorporated into the new technique and help constrain the retrieved aerosol refractive indices. An application of the technique to two TARFOX case studies yields the occurrence of vertical layers of distinct aerosol refractive indices. Values of the estimated complex aerosol refractive index range from 1.33 to 1.45 for the real part and 0.001 to 0.008 for the imaginary part. The methodology devised in this study

  3. Vertical profiles of black carbon concentration and particle number size distribution in the North China Plain

    NASA Astrophysics Data System (ADS)

    Ran, L.; Deng, Z.

    2013-12-01

    The vertical distribution of aerosols is of great importance to our understanding in the impacts of aerosols on radiation balance and climate, as well as air quality and public health. To better understand and estimate the effects of atmospheric components including trace gases and aerosols on atmospheric environment and climate, an intensive field campaign, Vertical Observations of trace Gases and Aerosols in the North China Plain (VOGA-NCP), was carried out from late July to early August 2013 over a rural site in the polluted NCP. During the campaign, vertical profiles of black carbon (BC) concentration and particle number size distribution were measured respectively by a micro-Aethalometer and an optical particle counter attached to a tethered balloon within 1000 m height. Meteorological parameters, including temperature, relative humidity, wind speed and wind direction, were measured simultaneously by a radiosonde also attached to the tethered balloon. Preliminary results showed distinct diurnal variations of the vertical distribution of aerosol total number concentration and BC concentration, following the development of the mixing layer. Generally, there was a well mixing of aerosols within the mixing layer and a sharp decrease above the mixing layer. Particularly, a small peak of BC concentrations was observed around 400-500 m height for several profiles. Further analysis would be needed to explain such phenomenon. It was also found that measured vertical profiles of BC using the filter-based method might be affected by the vertical distribution of relative humidity.

  4. Retrieving the Vertical Structure of the Effective Aerosol Complex Index of Refraction from a Combination of Aerosol in Situ and Remote Sensing Measurements During TARFOX

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Turco, R. P.; Liou, K. N.; Russell, P. B.; Bergstrom, R. W.; Schmid, B.; Livingston, J. M.; Hobbs, P. V.; Hartley, W. S.; Ismail, S.

    2000-01-01

    The largest uncertainty in estimates of the effects of atmospheric aerosols on climate stems from uncertainties in the determination of their microphysical properties, including the aerosol complex index of refraction, which in turn determines their optical properties. A novel technique is used to estimate the aerosol complex index of refraction in distinct vertical layers from a combination of aerosol in situ size distribution and remote sensing measurements during the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX). In particular, aerosol backscatter measurements using the NASA Langley LASE (Lidar Atmospheric Sensing Experiment) instrument and in situ aerosol size distribution data are utilized to derive vertical profiles of the 'effective' aerosol complex index of refraction at 815 nm (i.e., the refractive index that would provide the same backscatter signal in a forward calculation on the basis of the measured in situ particle size distributions for homogeneous, spherical aerosols). A sensitivity study shows that this method yields small errors in the retrieved aerosol refractive indices, provided the errors in the lidar derived aerosol backscatter are less than 30% and random in nature. Absolute errors in the estimated aerosol refractive indices are generally less than 0.04 for the real part and can be as much as 0.042 for the imaginary part in the case of a 30% error in the lidar-derived aerosol backscatter. The measurements of aerosol optical depth from the NASA Ames Airborne Tracking Sunphotometer (AATS-6) are successfully incorporated into the new technique and help constrain the retrieved aerosol refractive indices. An application of the technique to two TARFOX case studies yields the occurrence of vertical layers of distinct aerosol refractive indices. Values of the estimated complex aerosol refractive index range from 1.33 to 1.45 for the real part and 0.001 to 0.008 for the imaginary part. The methodology devised in this study

  5. Concepts for generating optimum vertical flight profiles

    NASA Technical Reports Server (NTRS)

    Sorensen, J. A.

    1979-01-01

    Algorithms for generating optimum vertical profiles are derived and examined. These algorithms form the basis for the design of onboard flight management concepts. The variations in the optimum vertical profiles (resulting from these concepts) due to variations in wind, takeoff weight, and range-to-destination are presented. Further considerations for mechanizing two different onboard methods of computing near-optimum flight profiles are then outlined. Finally, the results are summarized, and recommendations are made for further work. Technical details of optimum trajectory design, steering requirements for following these trajectories, and off-line computer programs for testing the concepts are included.

  6. Vertical Aerosol Backscatter Variability from an Airborne Focused Continuous Wave CO2 Lidar

    NASA Technical Reports Server (NTRS)

    Jarzembski, Maurice A.; Srivastava, Vandana; Rothermel, Jeffry

    1998-01-01

    Atmospheric aerosol backscatter measurements using a continuous wave focused Doppler lidar at 9.1 micron wavelength were obtained over western North America and the Pacific Ocean during 13 - 26 September, 1995 as part of National Aeronautics and Space Administration's (NASA) Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) mission on board the NASA DC8 aircraft. Backscatter variability was measured for approximately 52 flight hours, covering equivalent horizontal distance of approximately 25,000 km in the troposphere. Quasi-vertical backscatter profiles were also obtained during various ascents and descents which ranged between approximately 0.1 to 12.0 km altitude. Aerosol haze layers were encountered at different altitudes. Similarities and differences for aerosol loading over land and over ocean were observed. A mid-tropospheric aerosol backscatter background mode was found with modal value approximately 1O(exp -10)/m/sr, consistent with previous airborne and ground-based datasets.

  7. Atmospheric aerosol profiling with a bistatic imaging lidar system.

    PubMed

    Barnes, John E; Sharma, N C Parikh; Kaplan, Trevor B

    2007-05-20

    Atmospheric aerosols have been profiled using a simple, imaging, bistatic lidar system. A vertical laser beam is imaged onto a charge-coupled-device camera from the ground to the zenith with a wide-angle lens (CLidar). The altitudes are derived geometrically from the position of the camera and laser with submeter resolution near the ground. The system requires no overlap correction needed in monostatic lidar systems and needs a much smaller dynamic range. Nighttime measurements of both molecular and aerosol scattering were made at Mauna Loa Observatory. The CLidar aerosol total scatter compares very well with a nephelometer measuring at 10 m above the ground. The results build on earlier work that compared purely molecular scattered light to theory, and detail instrument improvements.

  8. Comparison of the water vapor and aerosol profiles

    NASA Astrophysics Data System (ADS)

    Penner, I. E.; Arshinov, M. Yu.; Balin, Yu. S.; Belan, B. D.; Voronin, B. A.; Kokhanenko, G. P.

    2014-11-01

    Analysis of the contents of water vapor and aerosol in the atmosphere measured by means of different instruments was performed based on the results of the comprehensive aerosol experiment carried out at the Institute of Atmospheric optics in May 2012. The data obtained using remote (lidar) and contact (balloon) methods were used. They are capable of obtaining the vertical profiles of the measured parameters with high spatial resolution. Lidar measurements of the water vapor content in the boundary layer of the atmosphere by Raman method have shown very good agreement with the data of measurements by balloon. Simultaneous lidar measurements of backscattering and mixing ratio of water vapor in the atmosphere give significant positive correlation of the contents of water vapor and aerosol in the layers.

  9. Reconstructing the vertical profile of humidity on the basis of the vertical profile of temperature

    NASA Technical Reports Server (NTRS)

    Bazlova, T. I.

    1974-01-01

    The vertical profile of humidity in the atmosphere is developed on the basis of the vertical profile of temperature using an empirical formula linking changes in humidity with changes in temperature and altitude. The atmosphere is divided into three layers by altitude, since the condition for the formation of humidity varies with altitude.

  10. Vertical structure of aerosols, temperature, and moisture associated with an intense African dust event observed over the eastern Caribbean

    NASA Astrophysics Data System (ADS)

    Jung, Eunsil; Albrecht, Bruce; Prospero, Joseph M.; Jonsson, Haflidi H.; Kreidenweis, Sonia M.

    2013-05-01

    unusually intense African dust event affected a large area of the western Atlantic and eastern Caribbean in early April 2010. Measurements made east of Barbados from the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter research aircraft are used to characterize particle size distributions; vertical distributions of aerosols, temperature, and moisture; and processes leading to the observed stratification in the boundary layer. The vertical profiles of various aerosol characterizations were similar on both days and show three layers with distinct aerosol and thermodynamic characteristics: the Saharan Air Layer (SAL; ~2.2 km ± 500 m), a subcloud layer (SCL; surface to ~500 m), and an intermediate layer extending between them. The SAL and SCL display well-mixed aerosol and thermodynamic characteristics; but the most significant horizontal and vertical variations in aerosols and thermodynamics occur in the intermediate layer. The aerosol variability observed in the intermediate layer is likely associated with modification by shallow cumulus convection occurring sometime in the prior history of the air mass as it is advected across the Atlantic. A comparison of the thermodynamic structure observed in the event from its origin over Africa with that when it reached Barbados indicates that the lower part of the SAL was moistened by surface fluxes as the air mass was advected across the Atlantic. Mixing diagrams using aerosol concentrations and water vapor mixing ratios as conserved parameters provide insight into the vertical transports and mixing processes that may explain the observed aerosol and thermodynamic variability in each layer.

  11. Comparison of Aerosol Classification From Airborne High Spectral Resolution Lidar and the CALIPSO Vertical Feature Mask

    NASA Technical Reports Server (NTRS)

    Burton, Sharon P.; Ferrare, Rich A.; Omar, Ali H.; Vaughan, Mark A.; Rogers, Raymond R.; Hostetler, Chris a.; Hair, Johnathan W.; Obland, Michael D.; Butler, Carolyn F.; Cook, Anthony L.; Harper, David B.

    2012-01-01

    Knowledge of aerosol composition and vertical distribution is crucial for assessing the impact of aerosols on climate. In addition, aerosol classification is a key input to CALIOP aerosol retrievals, since CALIOP requires an inference of the lidar ratio in order to estimate the effects of aerosol extinction and backscattering. In contrast, the NASA airborne HSRL-1 directly measures both aerosol extinction and backscatter, and therefore the lidar ratio (extinction-to-backscatter ratio). Four aerosol intensive properties from HSRL-1 are combined to infer aerosol type. Aerosol classification results from HSRL-1 are used here to validate the CALIOP aerosol type inferences.

  12. Seasonal variation of vertical distribution of aerosol single scattering albedo over Indian sub-continent: RAWEX aircraft observations

    NASA Astrophysics Data System (ADS)

    Suresh Babu, S.; Nair, Vijayakumar S.; Gogoi, Mukunda M.; Krishna Moorthy, K.

    2016-01-01

    To characterize the vertical distribution of aerosols and its seasonality (especially the single scattering albedo, SSA) extensive profiling of aerosol scattering and absorption coefficients have been carried out using an instrumented aircraft from seven base stations spread across the Indian mainland during winter 2012 and spring/pre-monsoon 2013 under the Regional Aerosol Warming Experiment (RAWEX). Spatial variation of the vertical profiles of the asymmetry parameter, the wavelength exponent of the absorption coefficient and the single scattering albedo, derived from the measurements, are used to infer the source characteristics of winter and pre-monsoon aerosols as well as the seasonality of free tropospheric aerosols. The relatively high value of the wavelength exponent of absorption coefficient over most of the regions indicates the contribution from biomass burning and dust aerosols up to lower free tropospheric altitudes. A clear enhancement in aerosol loading and its absorbing nature is seen at lower free troposphere levels (above the planetary boundary layer) over the entire mainland during spring/pre-monsoon season compared to winter, whereas concentration of aerosols within the boundary layer showed a decrease from winter to spring. This could have significant implications on the aerosol heating structure over the Indian region and hence the regional climate.

  13. Aerosol vertical distribution over east China from RIEMS-Chem simulation in comparison with CALIPSO measurements

    NASA Astrophysics Data System (ADS)

    Li, Jiawei; Han, Zhiwei

    2016-10-01

    The horizontal and vertical distributions of aerosol extinction coefficient (AEC) and mass concentration over east China in October 2010 were investigated by using an online-coupled regional climate model and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) data. Model performance was evaluated comprehensively against ground observations of meteorological variables and PM10 concentrations and CALIPSO retrieved AEC profiles, which demonstrated a good ability of the model in simulating spatial distribution and evolution of aerosol concentration and optical properties. Severe pollution episodes were found over wide areas of east China during the study period, with the maximum mean PM10 concentration exceeding 200 μg m-3 in the Chongqing district and a part of the lower reaches of the Yellow River on 8-10 October. Both CALIPSO retrievals and model simulations revealed high AEC values (≥1 km-1) often occurred within 2 km above ground over most areas of east China. AEC vertical profile in or in the vicinity of China major cities along CALIPSO orbit track exhibited two typical features: one was AEC reached its maximum (∼4 km-1) near the surface (<200 m) and decreased rapidly to < 0.1 km-1 at altitudes above 1 km, another one was AEC peaked at higher altitudes of about 0.5-1 km with a maximum up to 3 km-1. AEC vertical profile was strongly dependent on vertical distribution of both aerosol concentration, composition and relative humidity. The vertical cross sections over typical regions of east China exhibited a decreasing AEC in magnitude from the continent to the China seas. Over the continent, AEC was either maximum near the surface or peaked at higher altitudes (0.5-1.0 km) due to increases of relative humidity or aerosol concentration in those regions, whereas over the seas of China, AEC profile was characterized by peak values at an altitude around 1 km, mainly due to an elevated relative humidity there, which favored rapid aerosol

  14. Shortwave and longwave radiative forcings of aerosols depending on the vertical stratification of aerosols and clouds

    NASA Astrophysics Data System (ADS)

    Oikawa, Eiji; Suzuki, Kentaroh; Nakajima, Teruyuki; Nishizawa, Tomoaki

    2017-02-01

    We investigate four scenarios for estimating shortwave (SW) and longwave (LW) direct aerosol radiative forcing (DARF) at the top of atmosphere (TOA) using the global data set of the vertical distributions for aerosols and clouds of CALIPSO and CloudSat Level 2 products. One scenario is clear-sky (cloud-free) condition and three scenarios are cloudy-sky condition: the case that aerosols exists above clouds (AAC case), and the case that aerosols exist below high clouds such as cirrus, but without clouds below the aerosol layers (ABC case), and the case that aerosols are not observed in cloudy-sky condition. In clear-sky and ABC cases, aerosols mainly scatter sunlight and SWDARFs show negative values, except for bright surfaces, such as desert regions and the North and South Poles. In AAC case, aerosols absorb the reflected light from underlying low-level clouds to TOA, so that SWDARF at TOA shows positive value. Mineral dust absorbs the Earth's radiation and LWDARF indicates strong positive over Saharan and Arabian deserts. The global mean values of SW plus LW DARFs are -2.77, -0.77, and -1.40 Wm-2 under clear-sky, cloudy-sky, and all-sky conditions.

  15. Retrieval of Aerosol Profiles using Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS)

    NASA Astrophysics Data System (ADS)

    Yilmaz, Selami; Frieß, Udo; Apituley, Arnoud; Henzing, Bas; Baars, Holger; Heese, Birgit; Althausen, Dietrich; Adam, Mariana; Putaud, Jean-Philippe; Zieger, Paul; Platt, Ulrich

    2010-05-01

    Multi Axis Differential Absorption Spectroscopy (MAX-DOAS) is a well established measurement technique to derive atmospheric trace gas profiles. Using MAX-DOAS measurements of trace gases with a known vertical profile, like the oxygen-dimer O4, it is possible to retrieve information on atmospheric aerosols. Based on the optimal estimation method, we have developed an algorithm which fits simultaneously measured O4 optical densities and relative intensities at several wavelengths and elevation angles to values simulated by a radiative transfer model. Retrieval parameters are aerosol extinction profile and optical properties such as single scattering albedo, phase function and Angström exponent. In 2008 and 2009 several intercomparison campaigns with established aerosol measurement techniques took place in Cabauw/Netherlands, Melpitz/Germany, Ispra/Italy and Leipzig/Germany, where simultaneous DOAS, lidar, Sun photometer and Nephelometer measurements were performed. Here we present results of the intercomparisons for cloud free conditions. The correlation of the aerosol optical thickness retrieved by the DOAS technique and the Sun photometer shows coefficients of determination from 0.96 to 0.98 and slopes from 0.94 to 1.07. The vertical structure of the DOAS retrieved aerosol extinction profiles compare favourably with the structures seen by the backscatter lidar. However, the vertical spatial development of the boundary layer is reproduced with a lower resolution by the DOAS technique. Strategies for the near real-time retrieval of trace gas profiles, aerosol profiles and optical properties will be discussed as well.

  16. Daytime aerosol extinction profiles from the combination of CALIOP profiles and AERONET products

    NASA Astrophysics Data System (ADS)

    Marcos, C.; Pedrós, R.; Gómez-Amo, J. L.; Sicard, M.; Utrillas, M. P.; Muñoz, C.; Comerón, A.; Martinez-Lozano, J. A.

    2013-04-01

    The solar background illumination has a strong effect on CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) measurements, leading to a decrease in the signal-to-noise ratio of the lidar signal. Because of this, CALIOP level 2 data algorithms might be limited in the retrieval of the properties of the aerosols in the atmosphere. In this work, we present a methodology that combines CALIOP level 1 data with AERONET (Aerosol RObotic NETwork) measurements to retrieve aerosol extinction profiles and lidar ratios in daytime conditions. In this way, we fulfill a two-fold objective: first, we obtain more accurate daytime aerosol information; second, we supplement column integrated measurements from AERONET sun photometers with information about the vertical distribution of aerosols. The methodology has been applied to Burjassot (39.30° N, 0.25° W) and Barcelona (41.39° N, 2.11° E) AERONET stations in the Mediterranean coast of Spain in the period from June 2006 to September 2011. We have found good agreement for the extinction profiles in several study cases of ground lidar measurements in Barcelona, coincident with CALIOP overpasses. Finally, the methodology has proved to be useful for the study of special episodes such as Saharan dust outbreaks.

  17. Sensitivity of the atmospheric temperature profile to the aerosol absorption in the presence of dust

    NASA Astrophysics Data System (ADS)

    Gómez-Amo, J. L.; di Sarra, A.; Meloni, D.

    2014-12-01

    Radiative transfer simulations in the shortwave (SW) and longwave (LW) spectral regions have been carried out to investigate the time evolution of the atmospheric heating/cooling rates and their influence on the temperature profiles under different vertical distributions of the aerosol absorption. The case study is based on measurements made at Rome, Italy, on 20 June 2007, when a dust layer was present above the urban boundary layer (BL) and the column aerosol optical depth at 550 nm was about 0.37. Column-integrated aerosol optical depth and single scattering albedo, as well as vertical profiles of aerosol extinction and meteorological variables have been derived from observations and used in the simulations. Different profiles of the aerosol absorption are considered by varying the absorption of the BL aerosols and of the desert dust, without changing the overall columnar properties. Three scenarios have been considered, with absorbing (ABL) or scattering (SBL) particles in the BL, and with a vertically homogeneous case (HL), which is taken as the reference. Calculations show that, for the selected case, about 25% of the SW heating is offset by the LW cooling within the dust layer. Different longwave/all-wave contributions are observed in the BL, depending on the BL aerosol absorption. Changes of atmospheric temperature induced by aerosol-radiation interactions only, have been investigated, while interactions with the surface through changes of the latent and sensible heat flux have been neglected. The evolution of temperature is similar for the three scenarios within the dust layer, with a daytime increase and a smaller nighttime decrease. After 24 h, the increase of the atmospheric temperature due to the aerosol radiative processes is about 1 K. In the BL, the increase of temperature is strongly dependent on the aerosol absorption capability. The oscillatory behaviour of the temperature with time in the dust layer, and the different evolution in the BL are

  18. The Vertical Structure, Sources, and Evolution of Aerosols in the Mediterranean Region

    NASA Astrophysics Data System (ADS)

    Roberts, Greg; Bourrianne, Thierry; Léon, Jean-François; Pont, Véronique; Mallet, Marc; Lambert, Dominique; Augustin, Patrick; Dulac, François; Junkermann, Wolfgang

    2013-04-01

    The VESSAER campaign (VErtical Structure and Sources of AERosols in the Mediterranean Region) was designed to characterize the different sources of aerosol in the Mediterranean Basin and assess the regional impact of aerosol on cloud microphysical and radiative properties. VESSAER was conducted on an ultra-light aircraft in summer 2012. Research activities included ground-based observations in the central and northern regions of Corsica, as well as aerosol lidar and sunphotometer measurements near the eastern coast. The main scientific goals were to investigate local versus long-range sources of aerosol and cloud condensation nuclei (CCN) and their vertical stratification in the lower troposphere, study evolution and ageing due to atmospheric processes, and determine aerosol direct radiative impacts over a larger spatial scale. The background aerosol concentrations (D > 0.01 um) within the boundary layer in Corsica were nearly 2000 cm^-3 and increased to ca. 104 cm^-3 during pollution events when back-trajectories originated from coastal areas in France and Italy and the Po Valley. Nearly all of these particles were CCN-active at 0.38% supersaturation, indicating a relatively hygroscopic aerosol. Vertical profiles of aerosol hygroscopicity revealed that ageing (with respect to CCN-activity) of European emissions occurred exclusively in the boundary layer. Within two days, the European emissions had become hygroscopic, probably a result of cloud processing. In contrast, aerosol hygroscopicity did not change as a function of transport time in elevated aerosol layers, suggesting that photochemical ageing of less hygroscopic material is relatively slow compared to ageing processes in the boundary layer. The vertical profiles clearly showed the long-range transport of dust from the Saharan Desert and pollution from the European continent, which were the two major sources of aerosol during the campaign. Two of the research flights coincided with CALIPSO overpasses, when

  19. Raman Lidar Profiling of Aerosols Over the Central US; Diurnal Variability and Comparisons with the GOCART Model

    NASA Technical Reports Server (NTRS)

    Ferrare, R. A.; Chin, M.; Clayton, M.; Turner, D.

    2002-01-01

    We use profiles of aerosol extinction, water vapor mixing ratio, and relative humidity measured by the ARM SGP Raman lidar in northern Oklahoma to show how the vertical distributions of aerosol extinction and water vapor vary throughout the diurnal cycle. While significant (20-30%) variations in aerosol extinction occurred near the surface as well as aloft, smaller (approximately 10%) variations were observed in the diurnal variability of aerosol optical thickness (AOT). The diurnal variations in aerosol extinction profiles are well correlated with corresponding variations in the average relative humidity profiles. The water vapor mixing ratio profiles and integrated water vapor amounts generally show less diurnal variability. The Raman lidar profiles are also used to evaluate the aerosol optical thickness and aerosol extinction profiles simulated by the GOCART global aerosol model. Initial comparisons show that the AOT simulated by GOCART was in closer agreement with the AOT derived from the Raman lidar and Sun photometer measurements during November 2000 than during September 2000. For both months, the vertical variability in average aerosol extinction profiles simulated by GOCART is less than the variability in the corresponding Raman lidar profiles.

  20. Lidar Measurements of the Vertical Distribution of Aerosol Optical and Physical Properties over Central Asia

    DOE PAGES

    Chen, Boris B.; Sverdlik, Leonid G.; Imashev, Sanjar A.; ...

    2013-01-01

    The vertical structure of aerosol optical and physical properties was measured by Lidar in Eastern Kyrgyzstan, Central Asia, from June 2008 to May 2009. Lidar measurements were supplemented with surface-based measurements of PM 2.5 and PM 10 mass and chemical composition in both size fractions. Dust transported into the region is common, being detected 33% of the time. The maximum frequency occurred in the spring of 2009. Dust transported to Central Asia comes from regional sources, for example, Taklimakan desert and Aral Sea basin, and from long-range transport, for example, deserts of Arabia, Northeast Africa, Iran, and Pakistan. Regionalmore » sources are characterized by pollution transport with maximum values of coarse particles within the planetary boundary layer, aerosol optical thickness, extinction coefficient, integral coefficient of aerosol backscatter, and minimum values of the Ångström exponent. Pollution associated with air masses transported over long distances has different characteristics during autumn, winter, and spring. During winter, dust emissions were low resulting in high values of the Ångström exponent (about 0.51) and the fine particle mass fraction (64%). Dust storms were more frequent during spring with an increase in coarse dust particles in comparison to winter. The aerosol vertical profiles can be used to lower uncertainty in estimating radiative forcing.« less

  1. Seasonal variations of aerosol optical properties, vertical distribution and associated radiative effects in the Yangtze Delta Region of China

    SciTech Connect

    Liu, Jianjun; Zheng, Youfei; Li, Zhanqing; Flynn, Connor J.; Cribb, Maureen

    2012-02-09

    Four years of columnar aerosol particle optical properties (2006 to 2009) and one year database worth of aerosol particle vertical profile of 527 nm extinction coefficient (June 2008 to May 2009) are analyzed at Taihu in the central Yangtze Delta region in eastern China. Seasonal variations of aerosol optical properties, vertical distribution, and influence on shortwave radiation and heating rates were investigated. Multiyear variations of aerosol optical depths (AOD), Angstrom exponents, single scattering albedo (SSA) and asymmetry factor (ASY) are analyzed, together with the vertical profile of aerosol extinction. AOD is largest in summer and smallest in winter. SSAs exhibit weak seasonal variation with the smallest values occurring during winter and the largest during summer. The vast majority of aerosol particles are below 2 km, and about 62%, 67%, 67% and 83% are confined to below 1 km in spring, summer, autumn and winter, respectively. Five-day back trajectory analyses show that the some aerosols aloft are traced back to northern/northwestern China, as far as Mongolia and Siberia, in spring, autumn and winter. The presence of dust aerosols were identified based on the linear depolarization measurements together with other information (i.e., back trajectory, precipitation, aerosol index). Dust strongly impacts the vertical particle distribution in spring and autumn, with much smaller effects in winter. The annual mean aerosol direct shortwave radiative forcing (efficiency) at the bottom, top and within the atmosphere are -34.8 {+-} 9.1 (-54.4 {+-} 5.3), -8.2 {+-} 4.8 (-13.1 {+-} 1.5) and 26.7 {+-} 9.4 (41.3 {+-} 4.6) W/m{sup 2} (Wm{sup -2} T{sup -1}), respectively. The mean reduction in direct and diffuse radiation reaching surface amount to 109.2 {+-} 49.4 and 66.8 {+-} 33.3 W/m{sup 2}, respectively. Aerosols significantly alter the vertical profile of solar heating, with great implications for atmospheric stability and dynamics within the lower troposphere.

  2. Seasonal and diurnal variations of aerosol extinction profile and type distribution from CALIPSO 5-year observations

    NASA Astrophysics Data System (ADS)

    Huang, Lei; Jiang, Jonathan H.; Tackett, Jason L.; Su, Hui; Fu, Rong

    2013-05-01

    The new Level 3 aerosol profile data derived from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) provide a multiyear global aerosol distribution with high vertical resolution. We analyzed seasonal and diurnal variations of the vertical distributions of aerosol properties represented by 5-year CALIPSO data. Results show that dust, smoke, and polluted dust are the most frequently detected aerosol types during all seasons. Dust is the dominant type, especially in the middle to upper troposphere, over most areas during boreal spring and summer, while smoke and polluted dust tend to dominate during biomass burning seasons. The seasonal variations of dust layer top height and dust contribution to all-aerosol extinction are positively correlated with the seasonal variation of the dust occurrence frequency. The seasonal cycle of aerosol properties over west Australia is similar to that over biomass burning regime areas, despite its desert regime. In general, smoke is detected more frequently from the lower to middle troposphere; clean marine and polluted continental aerosols are detected more frequently, while polluted dust is detected less frequently, in the lower troposphere during nighttime than daytime. The all-aerosol extinction is generally larger, and the aerosol layer top is detected at high altitudes more frequently during nighttime than daytime. The diurnal changes of aerosol properties are similar within the same aerosol regime. Dust extinction shows little diurnal variation except when dust is the dominant aerosol type. The results contribute to an initial global 3-D aerosol climatology which will likely be extended and improved in the future.

  3. Vertical distribution of near-ground aerosol backscattering coefficient measured by a CCD side-scattering lidar

    NASA Astrophysics Data System (ADS)

    Tao, Zongming; Liu, Dong; Ma, Xiaomin; Shi, Bo; Shan, Huihui; Zhao, Ming; Xie, Chenbo; Wang, Yingjian

    2015-09-01

    The near-ground aerosols have the most impact on the human beings. Its fine spatial and temporal distribution, with which the environmental and meteorological departments concern themselves most, has not been elaborated very well due to the unavailable measurement tools. We present the continuous observations of the vertical profile of near-ground aerosol backscattering coefficients by employing our self-developed side-scattering lidar system based on charge-coupled device camera. During the experimental period from April 2013 to August 2014, four catalogs of aerosol backscattering coefficient profiles are found in the near ground. The continuous measurement is revealed by the contour plots measured during the whole night. These experimental results indicate that the aerosol backscattering coefficients in near ground are inhomogeneous and vary with altitude and time, which are very useful for the model researchers to study the regional air pollution and its climate impact.

  4. Potential of polarization lidar to provide profiles of CCN- and INP-relevant aerosol parameters

    NASA Astrophysics Data System (ADS)

    Mamouri, R. E.; Ansmann, A.

    2015-12-01

    We investigate the potential of polarization lidar to provide vertical profiles of aerosol parameters from which cloud condensation nucleus (CCN) and ice nucleating particle (INP) number concentrations can be estimated. We show that height profiles of number concentrations of aerosol particles with radius > 50 nm (APC50, reservoir of favorable CCN) and with radius > 250 nm (APC250, reservoir of favorable INP), as well as profiles of the aerosol particle surface area concentration (ASC, used in INP parameterization) can be retrieved from lidar-derived aerosol extinction coefficients (AEC) with relative uncertainties of a factor of around 2 (APC50), and of about 25-50 % (APC250, ASC). Of key importance is the potential of polarization lidar to identify mineral dust particles and to distinguish and separate the aerosol properties of basic aerosol types such as mineral dust and continental pollution (haze, smoke). We investigate the relationship between AEC and APC50, APC250, and ASC for the main lidar wavelengths of 355, 532 and 1064 nm and main aerosol types (dust, pollution, marine). Our study is based on multiyear Aerosol Robotic Network (AERONET) photometer observations of aerosol optical thickness and column-integrated particle size distribution at Leipzig, Germany, and Limassol, Cyprus, which cover all realistic aerosol mixtures of continental pollution, mineral dust, and marine aerosol. We further include AERONET data from field campaigns in Morocco, Cabo Verde, and Barbados, which provide pure dust and pure marine aerosol scenarios. By means of a simple relationship between APC50 and the CCN-reservoir particles (APCCCN) and published INP parameterization schemes (with APC250 and ASC as input) we finally compute APCCCN and INP concentration profiles. We apply the full methodology to a lidar observation of a heavy dust outbreak crossing Cyprus with dust up to 8 km height and to a case during which anthropogenic pollution dominated.

  5. Aerosol detection methods in lidar-based atmospheric profiling

    NASA Astrophysics Data System (ADS)

    Elbakary, Mohamed I.; Iftekharuddin, Khan M.; De Young, Russell; Afrifa, Kwasi

    2016-09-01

    A compact light detection and ranging (LiDAR) system provides aerosols profile measurements by identifying the aerosol scattering ratio as function of the altitude. The aerosol scattering ratios are used to obtain multiple aerosol intensive ratio parameters known as backscatter color ratio, depolarization ratio and lidar ratio. The aerosol ratio parameters are known to vary with aerosol type, size, and shape. Different methods in the literature are employed for detection and classification of aerosol from the measurements. In this paper, a comprehensive review for aerosol detection methods is presented. In addition, results of implemented methods of quantifying aerosols in the atmosphere on real data are compared and presented showing how the backscatter color, depolarization and lidar ratios vary with presence of aerosols in the atmosphere.

  6. Balloonborne measurements of ozone and aerosol profiles at McMurdo Station, Antarctica, during the austral spring of 1992

    SciTech Connect

    Johnson, B.J.; Deshler, T. )

    1993-01-01

    This paper reports some of the findings of an overall study of the ozone hole over Antarctica. Vertical profiles of ozone and aerosols were measured, and the inclusion of aerosols from the June 1991 eruption of Mount Pinatubo was of particular interest. 4 refs., 2 figs.

  7. RADIALLY MAGNETIZED PROTOPLANETARY DISK: VERTICAL PROFILE

    SciTech Connect

    Russo, Matthew; Thompson, Christopher

    2015-11-10

    This paper studies the response of a thin accretion disk to an external radial magnetic field. Our focus is on protoplanetary disks (PPDs), which are exposed during their later evolution to an intense, magnetized wind from the central star. A radial magnetic field is mixed into a thin surface layer, wound up by the disk shear, and pushed downward by a combination of turbulent mixing and ambipolar and ohmic drift. The toroidal field reaches much greater strengths than the seed vertical field that is usually invoked in PPD models, even becoming superthermal. Linear stability analysis indicates that the disk experiences the magnetorotational instability (MRI) at a higher magnetization than a vertically magnetized disk when both the effects of ambipolar and Hall drift are taken into account. Steady vertical profiles of density and magnetic field are obtained at several radii between 0.06 and 1 AU in response to a wind magnetic field B{sub r} ∼ (10{sup −4}–10{sup −2})(r/ AU){sup −2} G. Careful attention is given to the radial and vertical ionization structure resulting from irradiation by stellar X-rays. The disk is more strongly magnetized closer to the star, where it can support a higher rate of mass transfer. As a result, the inner ∼1 AU of a PPD is found to evolve toward lower surface density. Mass transfer rates around 10{sup −8} M{sub ⊙} yr{sup −1} are obtained under conservative assumptions about the MRI-generated stress. The evolution of the disk and the implications for planet migration are investigated in the accompanying paper.

  8. Vertical Structure and Sources of Aerosols in the Mediterranean Region (VESSAER)

    NASA Astrophysics Data System (ADS)

    Roberts, G. C.; Junkermann, W.; Leon, J.; Pont, V.; Mallet, M.; Augustin, P.; Dulac, F.

    2012-12-01

    The Mediterranean region has been identified as one of the most prominent global "Hot-Spots" in future climate change projections [Giorgi and Lionello, 2008] and is particularly characterized by its vulnerability to changes in the water cycle. To this end, the VESSAER campaign (VErtical Structure and Sources of AERosols in the Mediterranean Region) was designed to characterize the different sources of aerosol in the Mediterranean Basin and assess their regional impact on cloud microphysical and radiative properties. VESSAER was conducted on the ENDURO-KIT ultra-light aircraft [W. Junkermann, 2001] in late June-early July 2012. Activities include ground observations as well as aerosol lidar and sunphotometer measurements in conjunction with the airborne measurements. The VESSAER campaign complements existing ChArMEx (http://charmex.lsce.ipsl.fr/ ; PI: F. Dulac) and HyMeX (http://www.hymex.org/ ; PI: V. Ducroc and P. Drobinski) activities, which are the target of many European research institutes in 2012 and 2013. The main scientific goals during VESSAER are to investigate local versus long-range sources of aerosol and cloud condensation nuclei (CCN) and their vertical stratification in the lower troposphere, use aerosol hygroscopicity to study their evolution due to atmospheric processes, and couple in-situ airborne measurements with ground-based remote sensing to determine aerosol direct radiative impacts over a larger spatial scale. The background aerosol concentrations within the boundary layer (BL) in Corsica are nearly 2000 cm-3 (Dp > 10 nm); 50 cm-3 (Dp > 300 nm). We were surprised to find that nearly all of these particles are CCN-active at 0.3% supersaturation and presume that ageing and/or cloud processing play a role in rendering the aerosol in the Mediterranean Basin more hygroscopic. The vertical profiles during VESSAER clearly show the long-range transport of dust from the Saharan Desert and pollution from the European continent -- which were the two

  9. Novel Co:MgF2 lidar for aerosol profiler

    NASA Technical Reports Server (NTRS)

    Acharekar, M. A.

    1993-01-01

    Lidars are of great interest because of their unique capabilities in remote sensing applications in sounding of the atmosphere, meteorology, and climatology. In this small business innovative research (SBIR) phase II program, laser sources including Co:MgF2, CTH:YAG, CTH:YSGG, CT:YAG, and Er:Glass were evaluated. Modulator of fused silica and TeO2 materials with Brewster's angle end faces were used with these lasers as acousto-optical (AO) Q-switches. A higher hold-off energy and hence a higher Q-switched energy was obtained by using a high power RF driver. The report provides performance characteristics of these lasers. The tunable (1.75-2.50 microns) Co:MgF2 laser damaged the TeO2 Q-switch cell. However, the CTH:YAG laser operating at 2.09 microns provided output energy of over 300 mJ/p in 50 ns pulse width using the fused silica Q-switch. This Q-switched CTH:YAG laser was used in a breadboard vertical aerosol profiler. A 40 cm diameter telescope, InSb and InGaAs detectors were used in the receiver. The data obtained using this lidar is provided in the report. The data shows that the eye safe lidar using CTH:YAG laser for the vertical aerosol density and range measurements is the viable approach.

  10. High resolution humidity, temperature and aerosol profiling with MeteoSwiss Raman lidar

    NASA Astrophysics Data System (ADS)

    Dinoev, Todor; Arshinov, Yuri; Bobrovnikov, Sergei; Serikov, Ilya; Calpini, Bertrand; van den Bergh, Hubert; Parlange, Marc B.; Simeonov, Valentin

    2010-05-01

    Meteorological services rely, in part, on numerical weather prediction (NWP). Twice a day radiosonde observations of water vapor provide the required data for assimilation but this time resolution is insufficient to resolve certain meteorological phenomena. High time resolution temperature profiles from microwave radiometers are available as well but have rather low vertical resolution. The Raman LIDARs are able to provide temperature and humidity profiles with high time and range resolution, suitable for NWP model assimilation and validation. They are as well indispensible tools for continuous aerosol profiling for high resolution atmospheric boundary layer studies. To improve the database available for direct meteorological applications the Swiss meteo-service (MeteoSwiss), the Swiss Federal Institute of Technology in Lausanne (EPFL) and the Swiss National Science Foundation (SNSF) initiated a project to design and build an automated Raman lidar for day and night vertical profiling of tropospheric water vapor with the possibility to further upgrade it with an aerosol and temperature channels. The project was initiated in 2004 and RALMO (Raman Lidar for meteorological observations) was inaugurated in August 2008 at MeteoSwiss aerological station at Payerne. RALMO is currently operational and continuously profiles water vapor mixing ratio, aerosol backscatter ratio and aerosol extinction. The instrument is a fully automated, self-contained, eye-safe Raman lidar operated at 355 nm. Narrow field-of-view multi-telescope receiver and narrow band detection allow day and night-time vertical profiling of the atmospheric humidity. The rotational-vibrational Raman lidar responses from water vapor and nitrogen are spectrally separated by a high-throughput fiber coupled diffraction grating polychromator. The elastic backscatter and pure-rotational Raman lidar responses (PRR) from oxygen and nitrogen are spectrally isolated by a double grating polychromator and are used to

  11. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration

    PubMed Central

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H.; Henry, Mike; Baden, Daniel G.

    2009-01-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1 h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken and analyzed for brevetoxin and NaCl concentrations. In addition, the aerosol mass concentration was monitored in real time. The results indicated that during a non-exposure period in October 2004, no brevetoxin was detected in the water, resulting in non-detectable levels of brevetoxin in the aerosol. In March 2005, the time-averaged concentrations of brevetoxins in water samples were moderate, in the range of 5–10 μg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m3. The temporal profiles of red tide aerosol concentration in terms of mass, NaCl, and brevetoxin were in good agreement, indicating that NaCl and brevetoxins are components of the red tide aerosol. By continuously monitoring the marine aerosol and wind direction at Siesta Beach, we observed that the marine aerosol concentration varied as the wind direction changed. The temporal profile of the Florida red tide aerosol during a sampling period could be explained generally with the variation of wind direction. PMID:19879288

  12. Characterization of Florida red tide aerosol and the temporal profile of aerosol concentration.

    PubMed

    Cheng, Yung Sung; Zhou, Yue; Pierce, Richard H; Henry, Mike; Baden, Daniel G

    2010-05-01

    Red tide aerosols containing aerosolized brevetoxins are produced during the red tide bloom and transported by wind to coastal areas of Florida. This study reports the characterization of Florida red tide aerosols in human volunteer studies, in which an asthma cohort spent 1h on Siesta Beach (Sarasota, Florida) during aerosolized red tide events and non-exposure periods. Aerosol concentrations, brevetoxin levels, and particle size distribution were measured. Hourly filter samples were taken and analyzed for brevetoxin and NaCl concentrations. In addition, the aerosol mass concentration was monitored in real time. The results indicated that during a non-exposure period in October 2004, no brevetoxin was detected in the water, resulting in non-detectable levels of brevetoxin in the aerosol. In March 2005, the time-averaged concentrations of brevetoxins in water samples were moderate, in the range of 5-10 microg/L, and the corresponding brevetoxin level of Florida red tide aerosol ranged between 21 and 39 ng/m(3). The temporal profiles of red tide aerosol concentration in terms of mass, NaCl, and brevetoxin were in good agreement, indicating that NaCl and brevetoxins are components of the red tide aerosol. By continuously monitoring the marine aerosol and wind direction at Siesta Beach, we observed that the marine aerosol concentration varied as the wind direction changed. The temporal profile of the Florida red tide aerosol during a sampling period could be explained generally with the variation of wind direction.

  13. Comparison of vertical aerosol extinction coefficients from in-situ and LIDAR measurements

    NASA Astrophysics Data System (ADS)

    Rosati, B.; Herrmann, E.; Bucci, S.; Fierli, F.; Cairo, F.; Gysel, M.; Tillmann, R.; Größ, J.; Gobbi, G. P.; Di Liberto, L.; Di Donfrancesco, G.; Wiedensohler, A.; Weingartner, E.; Virtanen, A.; Mentel, T. F.; Baltensperger, U.

    2015-07-01

    Vertical profiles of aerosol optical properties were explored in a case study near the San Pietro Capofiume (SPC) ground station during the PEGASOS Po Valley campaign in the summer of 2012. A Zeppelin NT airship was employed to investigate the effect of the dynamics of the planetary boundary layer at altitudes between ~ 50-800 m above ground. Determined properties included the aerosol size distribution, the hygroscopic growth factor, the effective index of refraction and the light absorption coefficient. The first three parameters were used to retrieve the light scattering coefficient. Simultaneously, direct measurements of both the scattering and absorption coefficient were carried out at the SPC ground station. Additionally, a LIDAR system provided aerosol extinction coefficients for a vertically resolved comparison between in-situ and remote sensing results. First, the airborne results at low altitudes were validated with the ground measurements. Agreement within approximately ±25 and ±20% was found for the dry scattering and absorption coefficient, respectively. The single scattering albedo, ranged between 0.83 to 0.95, indicating the importance of the absorbing particles in the Po Valley region. A clear layering of the atmosphere was observed during the beginning of the flight (until ~ 10 local time) before the mixed layer (ML) was fully developed. Highest extinction coefficients were found at low altitudes, in the new ML, while values in the residual layer, which could be probed at the beginning of the flight at elevated altitudes, were lower. At the end of the flight (after ~ 12 local time) the ML was fully developed, resulting in constant extinction coefficients at all altitudes measured on the Zeppelin NT. LIDAR results captured these dynamic features well and good agreement was found for the extinction coefficients compared to the in-situ results, using fixed LIDAR ratios (LR) between 30 and 70 sr for the altitudes probed with the Zeppelin. These LR are

  14. MPL-Net Measurements of Aerosol and Cloud Vertical Distributions at Co-Located AERONET Sites

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; Campbell, James R.; Berkoff, Timothy A.; Spinhirne, James D.; Tsay, Si-Chee; Holben, Brent; Starr, David OC. (Technical Monitor)

    2002-01-01

    In the early 1990s, the first small, eye-safe, and autonomous lidar system was developed, the Micropulse Lidar (MPL). The MPL acquires signal profiles of backscattered laser light from aerosols and clouds. The signals are analyzed to yield multiple layer heights, optical depths of each layer, average extinction-to-backscatter ratios for each layer, and profiles of extinction in each layer. In 2000, several MPL sites were organized into a coordinated network, called MPL-Net, by the Cloud and Aerosol Lidar Group at NASA Goddard Space Flight Center (GSFC) using funding provided by the NASA Earth Observing System. tn addition to the funding provided by NASA EOS, the NASA CERES Ground Validation Group supplied four MPL systems to the project, and the NASA TOMS group contributed their MPL for work at GSFC. The Atmospheric Radiation Measurement Program (ARM) also agreed to make their data available to the MPL-Net project for processing. In addition to the initial NASA and ARM operated sites, several other independent research groups have also expressed interest in joining the network using their own instruments. Finally, a limited amount of EOS funding was set aside to participate in various field experiments each year. The NASA Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) project also provides funds to deploy their MPL during ocean research cruises. All together, the MPL-Net project has participated in four major field experiments since 2000. Most MPL-Net sites and field experiment locations are also co-located with sunphotometers in the NASA Aerosol Robotic Network. (AERONET). Therefore, at these locations data is collected on both aerosol and cloud vertical structure as well as column optical depth and sky radiance. Real-time data products are now available from most MPL-Net sites. Our real-time products are generated at times of AERONET aerosol optical depth (AOD) measurements. The AERONET AOD is used as input to our

  15. Interfacing the NRL 1-D High Vertical Resolution Aerosol Model with COAMPS

    DTIC Science & Technology

    2016-06-13

    TERM GOALS Identify, understand and quantify all the physical processes that govern the aerosols in the marine environment and develop a...size and composition distributions are required. Many of the aerosol source, sink and transformation processes are highly dependent on meteorological...parameters such as wind speed, humidity profile, clouds, precipitation scavenging, etc. The NRL 1-D aerosol- processes model includes all these

  16. What controls the vertical distribution of aerosol? Relationships between process sensitivity in HadGEM3-UKCA and inter-model variation from AeroCom Phase II

    NASA Astrophysics Data System (ADS)

    Kipling, Zak; Stier, Philip; Johnson, Colin E.; Mann, Graham W.; Bellouin, Nicolas; Bauer, Susanne E.; Bergman, Tommi; Chin, Mian; Diehl, Thomas; Ghan, Steven J.; Iversen, Trond; Kirkevåg, Alf; Kokkola, Harri; Liu, Xiaohong; Luo, Gan; van Noije, Twan; Pringle, Kirsty J.; von Salzen, Knut; Schulz, Michael; Seland, Øyvind; Skeie, Ragnhild B.; Takemura, Toshihiko; Tsigaridis, Kostas; Zhang, Kai

    2016-02-01

    The vertical profile of aerosol is important for its radiative effects, but weakly constrained by observations on the global scale, and highly variable among different models. To investigate the controlling factors in one particular model, we investigate the effects of individual processes in HadGEM3-UKCA and compare the resulting diversity of aerosol vertical profiles with the inter-model diversity from the AeroCom Phase II control experiment. In this way we show that (in this model at least) the vertical profile is controlled by a relatively small number of processes, although these vary among aerosol components and particle sizes. We also show that sufficiently coarse variations in these processes can produce a similar diversity to that among different models in terms of the global-mean profile and, to a lesser extent, the zonal-mean vertical position. However, there are features of certain models' profiles that cannot be reproduced, suggesting the influence of further structural differences between models. In HadGEM3-UKCA, convective transport is found to be very important in controlling the vertical profile of all aerosol components by mass. In-cloud scavenging is very important for all except mineral dust. Growth by condensation is important for sulfate and carbonaceous aerosol (along with aqueous oxidation for the former and ageing by soluble material for the latter). The vertical extent of biomass-burning emissions into the free troposphere is also important for the profile of carbonaceous aerosol. Boundary-layer mixing plays a dominant role for sea salt and mineral dust, which are emitted only from the surface. Dry deposition and below-cloud scavenging are important for the profile of mineral dust only. In this model, the microphysical processes of nucleation, condensation and coagulation dominate the vertical profile of the smallest particles by number (e.g. total CN > 3 nm), while the profiles of larger particles (e.g. CN > 100 nm) are controlled by the

  17. What Controls the Vertical Distribution of Aerosol? Relationships Between Process Sensitivity in HadGEM3-UKCA and Inter-Model Variation from AeroCom Phase II

    NASA Technical Reports Server (NTRS)

    Kipling, Zak; Stier, Philip; Johnson, Colin E.; Mann, Graham W.; Bellouin, Nicolas; Bauer, Susanne E.; Bergman, Tommi; Chin, Mian; Diehl, Thomas; Ghan, Steven J.; Tsigaridis, Kostas

    2016-01-01

    The vertical profile of aerosol is important for its radiative effects, but weakly constrained by observations on the global scale, and highly variable among different models. To investigate the controlling factors in one particular model, we investigate the effects of individual processes in HadGEM3-UKCA and compare the resulting diversity of aerosol vertical profiles with the inter-model diversity from the AeroCom Phase II control experiment. In this way we show that (in this model at least) the vertical profile is controlled by a relatively small number of processes, although these vary among aerosol components and particle sizes. We also show that sufficiently coarse variations in these processes can produce a similar diversity to that among different models in terms of the global-mean profile and, to a lesser extent, the zonal-mean vertical position. However, there are features of certain models' profiles that cannot be reproduced, suggesting the influence of further structural differences between models. In HadGEM3-UKCA, convective transport is found to be very important in controlling the vertical profile of all aerosol components by mass. In-cloud scavenging is very important for all except mineral dust. Growth by condensation is important for sulfate and carbonaceous aerosol (along with aqueous oxidation for the former and ageing by soluble material for the latter). The vertical extent of biomass-burning emissions into the free troposphere is also important for the profile of carbonaceous aerosol. Boundary-layer mixing plays a dominant role for sea salt and mineral dust, which are emitted only from the surface. Dry deposition and below-cloud scavenging are important for the profile of mineral dust only. In this model, the microphysical processes of nucleation, condensation and coagulation dominate the vertical profile of the smallest particles by number (e.g. total CN >3 nm), while the profiles of larger particles (e.g. CN>100 nm) are controlled by the

  18. What controls the vertical distribution of aerosol? Relationships between process sensitivity in HadGEM3-UKCA and inter-model variation from AeroCom Phase II

    NASA Astrophysics Data System (ADS)

    Kipling, Z.; Stier, P.; Johnson, C. E.; Mann, G. W.; Bellouin, N.; Bauer, S. E.; Bergman, T.; Chin, M.; Diehl, T.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Kokkola, H.; Liu, X.; Luo, G.; van Noije, T.; Pringle, K. J.; von Salzen, K.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2015-09-01

    The vertical profile of aerosol is important for its radiative effects, but weakly constrained by observations on the global scale, and highly variable among different models. To investigate the controlling factors, we investigate the effects of individual processes in one particular model (HadGEM3-UKCA), and compare the resulting diversity of aerosol vertical profiles with the inter-model diversity from the AeroCom Phase II control experiment. In this way we show that (in this model at least) the vertical profile is controlled by a relatively small number of processes, although these vary among aerosol components and particle sizes. We also show that sufficiently coarse variations in these processes can produce a similar diversity to that among different models in terms of the global mean profile and zonal-mean vertical position. However, there are features of certain models' profiles that cannot be reproduced, suggesting the influence of further structural differences between models. Convective transport is found to be very important in controlling the vertical profile of all aerosol components by mass. In-cloud scavenging is very important for all except mineral dust. Growth by condensation is important for sulphate and carbonaceous aerosol (along with aqueous oxidation for the former and ageing by soluble material for the latter). The vertical extent of biomass-burning emissions into the free troposphere is also important for the profile of carbonaceous aerosol. Boundary-layer mixing plays a dominant role for sea-salt and mineral dust, which are emitted only from the surface. Dry deposition and below-cloud scavenging are important for the profile of mineral dust only. In this model, the microphysical processes of nucleation, condensation and coagulation dominate the vertical profile of the smallest particles by number, while the profiles of larger particles are controlled by the same processes as the component mass profiles, plus the size distribution of

  19. A complete climatology of the aerosol vertical distribution on Mars from MEx/SPICAM UV solar occultations

    NASA Astrophysics Data System (ADS)

    Määttänen, Anni; Listowski, Constantino; Montmessin, Franck; Maltagliati, Luca; Reberac, Aurélie; Joly, Lilian; Bertaux, Jean-Loup

    2013-04-01

    We present the first results on solar occultations performed with the UV channel of SPICAM, on board Mars Express. From the dataset of over 900 occultations (performed between April 2004 and October 2011), about 640 atmospheric profiles of the martian atmosphere were derived. This dataset, spanning four martian years, allows characterization of the seasonal evolution and inter-annual comparisons of ozone and suspended particles. The dataset also includes observations of the Mars Year (MY) 28 global dust storm. In this paper the aforementioned data are analyzed with a focus on the aerosol profiles. We have mapped the seasonal behavior of the near-surface haze, revealing the typical behavior of the martian aerosol cycle, where the season most prone to develop dust storms (southern summer) shows aerosols lofted high in the atmosphere, whereas in the polar regions the aerosols are confined near the surface. More generally, aerosols seem to remain in the lower atmosphere at high latitudes and progressively penetrate to higher altitudes towards the tropics. This prevailing trend is probably related to enhanced atmospheric circulation at tropical regions due to high insolation and/or to higher cloud formation level in a warmer atmosphere. The dataset reveals frequent aerosol layers, found above or within the persistent near-surface haze. We have observed single and multiple layers (up to three layers in one profile) and we have mapped their properties. The highest layer altitudes observed during the global dust storm in the southern hemisphere, where thick layers form high above the abundant lower atmosphere dust haze. We present results on the analyzed Ångström coefficient α and its vertical variations. We also discuss the conversion of α into particle effective radius and present some examples of the effective radius vertical behavior.

  20. Autonomous Ozone and Aerosol LIDAR Profiling of the Troposphere: A Synergistic Approach

    NASA Astrophysics Data System (ADS)

    Strawbridge, K. B.

    2015-12-01

    LIDAR technology is an excellent tool to probe the complex vertical structure of the atmosphere at high spatial and temporal resolution. This provides the critical vertical context for the interpretation of ground-based chemistry measurements, airborne measurements and model/satellite verification and validation. In recent years, Environment Canada has designed several autonomous aerosol LIDAR systems for deployment across several regions of Canada. The current system builds on the successes of these autonomous LIDARS but using a synergistic approach by combining tropospheric ozone DIAL (Differential Absorption LIDAR) technology with simultaneous 3+2+1 aerosol LIDAR measurements. It operates 24 hours a day, seven days a week except during precipitation events. The system is operated remotely and the data are updated every hour to a website to allow near real-time capability. A few case studies are shown emphasizing the synergistic approach of coupling ozone and aerosol profiles to better understand air quality impacts on local and regional scales.

  1. Estimating tropical vertical motion profile shapes from satellite observations

    NASA Astrophysics Data System (ADS)

    Back, L. E.; Handlos, Z.

    2013-12-01

    The vertical structure of tropical deep convection strongly influences interactions with larger scale circulations and climate. This research focuses on investigating this vertical structure and its relationship with mesoscale tropical weather states. We test the hypothesis that vertical motion shape varies in association with weather state type. We estimate mean state vertical motion profile shapes for six tropical weather states defined using cloud top pressure and optical depth properties from the International Satellite Cloud Climatology Project. The relationship between vertical motion and the dry static energy budget are utilized to set up a regression analysis that empirically determines two modes of variability in vertical motion from reanalysis data. We use these empirically determined modes, this relationship and surface convergence to estimate vertical motion profile shape from observations of satellite retrievals of rainfall and surface convergence. We find that vertical motion profile shapes vary systematically between different tropical weather states. The "isolated systems" regime exhibits a more ''bottom-heavy'' profile shape compared to the convective/thick cirrus and vigorous deep convective regimes, with maximum upward vertical motion occurring in the lower troposphere rather than the middle to upper troposphere. The variability we observe with our method does not coincide with that expected based on conventional ideas about how stratiform rain fraction and vertical motion are related.

  2. Potential of polarization lidar to provide profiles of CCN- and INP-relevant aerosol parameters

    NASA Astrophysics Data System (ADS)

    Mamouri, Rodanthi-Elisavet; Ansmann, Albert

    2016-05-01

    We investigate the potential of polarization lidar to provide vertical profiles of aerosol parameters from which cloud condensation nucleus (CCN) and ice nucleating particle (INP) number concentrations can be estimated. We show that height profiles of particle number concentrations n50, dry considering dry aerosol particles with radius > 50 nm (reservoir of CCN in the case of marine and continental non-desert aerosols), n100, dry (particles with dry radius > 100 nm, reservoir of desert dust CCN), and of n250, dry (particles with dry radius > 250 nm, reservoir of favorable INP), as well as profiles of the particle surface area concentration sdry (used in INP parameterizations) can be retrieved from lidar-derived aerosol extinction coefficients σ with relative uncertainties of a factor of 1.5-2 in the case of n50, dry and n100, dry and of about 25-50 % in the case of n250, dry and sdry. Of key importance is the potential of polarization lidar to distinguish and separate the optical properties of desert aerosols from non-desert aerosol such as continental and marine particles. We investigate the relationship between σ, measured at ambient atmospheric conditions, and n50, dry for marine and continental aerosols, n100, dry for desert dust particles, and n250, dry and sdry for three aerosol types (desert, non-desert continental, marine) and for the main lidar wavelengths of 355, 532, and 1064 nm. Our study is based on multiyear Aerosol Robotic Network (AERONET) photometer observations of aerosol optical thickness and column-integrated particle size distribution at Leipzig, Germany, and Limassol, Cyprus, which cover all realistic aerosol mixtures. We further include AERONET data from field campaigns in Morocco, Cabo Verde, and Barbados, which provide pure dust and pure marine aerosol scenarios. By means of a simple CCN parameterization (with n50, dry or n100, dry as input) and available INP parameterization schemes (with n250, dry and sdry as input) we finally compute

  3. A method for retrieving vertical distribution of aerosol mass concentration in atmosphere from results of lidar sensing at Nd:YAG laser wavelengths

    NASA Astrophysics Data System (ADS)

    Lisenko, S. A.; Kugeiko, M. M.

    2011-03-01

    A method for retrieving the vertical profiles of atmospheric aerosol concentration from the results of lidar sensing at Ng:YAG laser wavelengths is developed based on the found multiple regressions between the optical location characteristics of aerosol at wavelengths of 0.355, 0.532, and 1.064 nm, as well as between the aerosol backscattering coefficient at these wavelengths and the concentration of aerosol particles. The method does not require solving ill-posed inverse problems and minimizes the use of a priori information. The reliability and generality of regressions obtained are confirmed by their good agreement with the AERO-NET data. The method efficiency is demonstrated by numerical experiments on retrieving profiles of back-scattering coefficients and concentration that corresponds to different optical models of aerosol.

  4. Measurements of Atmospheric Aerosol Vertical Distributions above Svalbard, Norway using Unmanned Aerial Systems (UAS)

    NASA Astrophysics Data System (ADS)

    Bates, T. S.; Johnson, J. E.; Stalin, S.; Telg, H.; Murphy, D. M.; Burkhart, J. F.; Quinn, P.; Storvold, R.

    2015-12-01

    Atmospheric aerosol vertical distributions were measured above Svalbard, Norway in April 2015 to investigate the processes controlling aerosol concentrations and radiative effects. The aerosol payload was flown in a NOAA/PMEL MANTA Unmanned Aerial System (UAS) on 9 flights totaling 19 flight hours. Measurements were made of particle number concentration and aerosol light absorption at three wavelengths, similar to those conducted in April 2011 (Bates et al., Atmos. Meas. Tech., 6, 2115-2120, 2013). A filter sample was collected on each flight for analyses of trace elements. Additional measurements in the aerosol payload in 2015 included aerosol size distributions obtained using a Printed Optical Particle Spectrometer (POPS) and aerosol optical depth obtained using a four wavelength miniature Scanning Aerosol Sun Photometer (miniSASP). The data show most of the column aerosol mass and resulting optical depth in the boundary layer but frequent aerosol layers aloft with high particle number concentration (2000 cm-3) and enhanced aerosol light absorption (1 Mm-1). Transport of these aerosol layers was assessed using FLEXPART particle dispersion models. The data contribute to an assessment of sources of BC to the Arctic and potential climate impacts.

  5. MARLI: MARs LIdar for Global Wind Profiles and Aerosol Profiles from Orbit

    NASA Astrophysics Data System (ADS)

    Abshire, J. B.; Guzewich, S. D.; Smith, M. D.; Riris, H.; Sun, X.; Gentry, B. M.; Yu, A.; Allan, G. R.

    2016-10-01

    Winds are the key variable to understand atmospheric transport and to answer fundamental questions about the three primary cycles of the Mars climate. We are developing a new orbital lidar to directly measure both wind profiles and aerosol profiles.

  6. Vertical distributions of aerosol optical properties during haze and floating dust weather in Shanghai

    NASA Astrophysics Data System (ADS)

    Liu, Qiong; Wang, Yuan; Kuang, Zhongyu; Fang, Sihua; Chen, Yonghang; Kang, Yanming; Zhang, Hua; Wang, Daoyuan; Fu, Yingying

    2016-06-01

    A comparative study on the vertical distributions of aerosol optical properties during haze and floating dust weather in Shanghai was conducted based on the data obtained from a micro pulse lidar. There was a distinct difference in layer thickness and extinction coefficient under the two types of weather conditions. Aerosols were concentrated below 1 km and the aerosol extinction coefficients ranged from 0.25 to 1.50 km-1 on haze days. In contrast, aerosols with smaller extinction coefficients (0.20-0.35 km-1) accumulated mainly from the surface to 2 km on floating dust days. The seasonal variations of extinction and aerosol optical depth (AOD) for both haze and floating dust cases were similar—greatest in winter, smaller in spring, and smallest in autumn. More than 85% of the aerosols appeared in the atmosphere below 1 km during severe haze and floating dust weather. The diurnal variation of the extinction coefficient of haze exhibited a bimodal shape with two peaks in the morning or at noon, and at nightfall, respectively. The aerosol extinction coefficient gradually increased throughout the day during floating dust weather. Case studies showed that haze aerosols were generated from the surface and then lifted up, but floating dust aerosols were transported vertically from higher altitude to the surface. The AOD during floating dust weather was higher than that during haze. The boundary layer was more stable during haze than during floating dust weather.

  7. Vertical Profiles for Turbojet-Powered Aircraft

    NASA Technical Reports Server (NTRS)

    Sorensen, J. A.; Waters, M. H.

    1983-01-01

    OPTIM generates profile of altitude, airspeed, and flightpath angle as function of range between given set or origin and destination points for particular models of transport aircraft. Profile is optimized in sense of minimizing fuel or time or in minimizing direct operating cost expressed as combination of fuel and time.

  8. Studying the vertical aerosol extinction coefficient by comparing in situ airborne data and elastic backscatter lidar

    NASA Astrophysics Data System (ADS)

    Rosati, Bernadette; Herrmann, Erik; Bucci, Silvia; Fierli, Federico; Cairo, Francesco; Gysel, Martin; Tillmann, Ralf; Größ, Johannes; Gobbi, Gian Paolo; Di Liberto, Luca; Di Donfrancesco, Guido; Wiedensohler, Alfred; Weingartner, Ernest; Virtanen, Annele; Mentel, Thomas F.; Baltensperger, Urs

    2016-04-01

    Vertical profiles of aerosol particle optical properties were explored in a case study near the San Pietro Capofiume (SPC) ground station during the PEGASOS Po Valley campaign in the summer of 2012. A Zeppelin NT airship was employed to investigate the effect of the dynamics of the planetary boundary layer at altitudes between ˜ 50 and 800 m above ground. Determined properties included the aerosol particle size distribution, the hygroscopic growth factor, the effective index of refraction and the light absorption coefficient. The first three parameters were used to retrieve the light scattering coefficient. Simultaneously, direct measurements of both the scattering and absorption coefficient were carried out at the SPC ground station. Additionally, a single wavelength polarization diversity elastic lidar system provided estimates of aerosol extinction coefficients using the Klett method to accomplish the inversion of the signal, for a vertically resolved comparison between in situ and remote-sensing results. Note, however, that the comparison was for the most part done in the altitude range where the overlap function is incomplete and accordingly uncertainties are larger. First, the airborne results at low altitudes were validated with the ground measurements. Agreement within approximately ±25 and ±20 % was found for the dry scattering and absorption coefficient, respectively. The single scattering albedo, ranged between 0.83 and 0.95, indicating the importance of the absorbing particles in the Po Valley region. A clear layering of the atmosphere was observed during the beginning of the flight (until ˜ 10:00 LT - local time) before the mixing layer (ML) was fully developed. Highest extinction coefficients were found at low altitudes, in the new ML, while values in the residual layer, which could be probed at the beginning of the flight at elevated altitudes, were lower. At the end of the flight (after ˜ 12:00 LT) the ML was fully developed, resulting in

  9. Effect of particle settling on lidar profiles of long-range transported Saharan aerosols

    NASA Astrophysics Data System (ADS)

    Gasteiger, Josef; Groß, Silke

    2016-04-01

    A large amount of desert aerosol is transported in the Saharan Air Layer (SAL) westwards from Africa over the Atlantic Ocean. Lidar profiles of transported Saharan aerosol may contain some information about the vertically-resolved aerosol microphysics that could be used to characterize processes that affected the measured aerosol during transport. We present modelled lidar profiles of long-range transported Saharan aerosol assuming that initially the SAL is well-mixed and that there is no vertical mixing of air within the SAL as soon as it reaches the Atlantic. We consider Stokes gravitational settling of aerosol particles over the ocean. The lidar profiles are calculated using optical models for irregularly-shaped mineral dust particles assuming settling-induced particle removal as function of distance from the SAL top. Within the SAL we find a decrease of both the backscatter coefficients and the linear depolarization ratios with decreasing distance from the SAL top. For example, the linear depolarization ratio at a wavelength of 532nm decreases from 0.289 at 1000m to 0.256 at 200m and 0.215 at 100m below SAL top. We compare the modelled backscatter coefficients and linear depolarization ratios to ground-based lidar measurements performed during the SALTRACE field campaign in Barbados (Caribbean) and find agreement within the estimated uncertainties. We discuss the uncertainties of our modeling approach in our presentation. Assumed mineral dust particle shapes, assumed particle mixture properties, and assumptions about processes in the SAL over the continent and the ocean are important aspects to be considered. Uncertainties are relevant for the potential of lidar measurements of transported Saharan dust to learn something about processes occuring in the SAL during long-range transport. We also compare our modeling results to modeling results previously published in the literature.

  10. Analysis of DIAL/HSRL aerosol backscatter and extinction profiles during the SEAC4RS campaign with an aerosol assimilation system

    NASA Astrophysics Data System (ADS)

    Weaver, C. J.; da Silva, A. M., Jr.; Colarco, P. R.; Randles, C. A.

    2015-12-01

    We retrieve aerosol concentrations and optical information from vertical profiles of airborne 532 nm extinction and 532 and 1064 nm backscatter measurements made during the SEAC4RS summer 2013 campaign. The observations are from the High Spectral Resolution Lidar (HSRL) Airborne Differential Absorption Lidar (DIAL) on board the NASA DC-8. Instead of retrieving information about aerosol microphysical properties such as indexes of refraction, we seek information more directly applicable to an aerosol transport model - in our case the Goddard Chemistry Aerosol Radiation and Transport (GOCART) module used in the GEOS-5 Earth modeling system. A joint atmosphere/aerosol mini-reanalysis was performed for the SEAC4RS period using GEOS-5. The meteorological reanalysis followed the MERRA-2 atmospheric reanalysis protocol, and aerosol information from MODIS, MISR, and AERONET provided a constraint on the simulated aerosol optical depth (i.e., total column loading of aerosols). We focus on the simulated concentrations of 10 relevant aerosol species simulated by the GOCART module: dust, sulfate, and organic and black carbon. Our first retrieval algorithm starts with the SEAC4RS mini-reanalysis and adjusts the concentration of each GOCART aerosol species so that differences between the observed and simulated backscatter and extinction measurements are minimized. In this case, too often we are unable to simulate the observations by simple adjustment of the aerosol concentrations. A second retrieval approach adjusts both the aerosol concentrations and the optical parameters (i.e., assigned mass extinction efficiency) associated with each GOCART species. We present results from DC-8 flights over smoke from forest fires over the western US using both retrieval approaches. Finally, we compare our retrieved quantities with in-situ observations of aerosol absorption, scattering, and mass concentrations at flight altitude.

  11. Doppler Lidar Measurements of Tropospheric Wind Profiles Using the Aerosol Double Edge Technique

    NASA Technical Reports Server (NTRS)

    Gentry, Bruce M.; Li, Steven X.; Mathur, Savyasachee; Korb, C. Laurence; Chen, Huailin

    2000-01-01

    The development of a ground based direct detection Doppler lidar based on the recently described aerosol double edge technique is reported. A pulsed, injection seeded Nd:YAG laser operating at 1064 nm is used to make range resolved measurements of atmospheric winds in the free troposphere. The wind measurements are determined by measuring the Doppler shift of the laser signal backscattered from atmospheric aerosols. The lidar instrument and double edge method are described and initial tropospheric wind profile measurements are presented. Wind profiles are reported for both day and night operation. The measurements extend to altitudes as high as 14 km and are compared to rawinsonde wind profile data from Dulles airport in Virginia. Vertical resolution of the lidar measurements is 330 m and the rms precision of the measurements is a low as 0.6 m/s.

  12. Long-term impacts of aerosols on vertical development of cloud and precipitation

    SciTech Connect

    Li Z.; Liu Y.; Niu, F.; Fan, J.; Rosenfeld, D.; Ding, Y.

    2011-11-13

    Aerosols alter cloud density and the radiative balance of the atmosphere. This leads to changes in cloud microphysics and atmospheric stability, which can either suppress or foster the development of clouds and precipitation. The net effect is largely unknown, but depends on meteorological conditions and aerosol properties. Here, we examine the long-term impact of aerosols on the vertical development of clouds and rainfall frequencies, using a 10-year dataset of aerosol, cloud and meteorological variables collected in the Southern Great Plains in the United States. We show that cloud-top height and thickness increase with aerosol concentration measured near the ground in mixed-phase clouds-which contain both liquid water and ice-that have a warm, low base. We attribute the effect, which is most significant in summer, to an aerosol-induced invigoration of upward winds. In contrast, we find no change in cloud-top height and precipitation with aerosol concentration in clouds with no ice or cool bases. We further show that precipitation frequency and rain rate are altered by aerosols. Rain increases with aerosol concentration in deep clouds that have a high liquid-water content, but declines in clouds that have a low liquid-water content. Simulations using a cloud-resolving model confirm these observations. Our findings provide unprecedented insights of the long-term net impacts of aerosols on clouds and precipitation.

  13. Vertical profiles of optical and microphysical particle properties above the northern Indian Ocean during CARDEX 2012

    NASA Astrophysics Data System (ADS)

    Höpner, F.; Bender, F. A.-M.; Ekman, A. M. L.; Praveen, P. S.; Bosch, C.; Ogren, J. A.; Andersson, A.; Gustafsson, Ö.; Ramanathan, V.

    2016-01-01

    A detailed analysis of optical and microphysical properties of aerosol particles during the dry winter monsoon season above the northern Indian Ocean is presented. The Cloud Aerosol Radiative Forcing Experiment (CARDEX), conducted from 16 February to 30 March 2012 at the Maldives Climate Observatory on Hanimaadhoo island (MCOH) in the Republic of the Maldives, used autonomous unmanned aerial vehicles (AUAV) to perform vertical in situ measurements of particle number concentration, particle number size distribution as well as particle absorption coefficients. These measurements were used together with surface- based Mini Micro Pulse Lidar (MiniMPL) observations and aerosol in situ and off-line measurements to investigate the vertical distribution of aerosol particles.Air masses were mainly advected over the Indian subcontinent and the Arabian Peninsula. The mean surface aerosol number concentration was 1717 ± 604 cm-3 and the highest values were found in air masses from the Bay of Bengal and Indo-Gangetic Plain (2247 ± 370 cm-3). Investigations of the free tropospheric air showed that elevated aerosol layers with up to 3 times higher aerosol number concentrations than at the surface occurred mainly during periods with air masses originating from the Bay of Bengal and the Indo-Gangetic Plain. This feature is different compared to what was observed during the Indian Ocean Experiment (INDOEX) conducted in winter 1999, where aerosol number concentrations generally decreased with height. In contrast, lower particle absorption at the surface (σabs(520 nm) = 8.5 ± 4.2 Wm-1) was found during CARDEX compared to INDOEX 1999.Layers with source region specific single-scattering albedo (SSA) values were derived by combining vertical in situ particle absorption coefficients and scattering coefficients calculated with Mie theory. These SSA layers were utilized to calculate vertical particle absorption profiles from MiniMPL profiles. SSA surface values for 550 nm for dry

  14. Vertical distribution of aerosols and shortwave radiative forcing over the Indo-Gangetic Basin during three major dust storms of 2010

    NASA Astrophysics Data System (ADS)

    Kumar, Sarvan; Singh, Abhay Kumar

    Abstract: The present study aims to analyze the Aerosol Radiative Forcing (ARF) and vertical distribution of aerosols over Kanpur (located in central Indo-Gangetic Basin; IGB) during the three (20 April, 28 May and 2 June, 2010) intense dust-storm events in the pre-monsoon season, using the synergy of ground and satellite observations and SBDART simulation. The analysis reveals considerable changes in the aerosol vertical profiles and ARF during the dust-storm events highlighting the important role of dust in the aerosol load and ARF properties over the IGB. The CALIOP-derived aerosol properties show vertically elevated aerosol profiles (up to 4 km altitude), majorly consisting of dust particles during the dust event. The maximum daily average top of the atmosphere (TOA), atmosphere (ATM) and surface (SRF) forcing is found to be -40.95, 60.65 W/m2 and -101.59W/m2 during the dust events respectively. A strong correlation is found between AOD at 500 nm and the ARF. The correlation coefficient (R2) between AOD and ARF is found to be 0.74, 0.46 and 0.84 at TOA, ATM and SRF respectively. The slope of the regression line gives the aerosol forcing efficiency at 500nm of about 24.29, -19.85 and -44.15 W/m2 at the ATM, TOA and SRF respectively. The ARF is found to increase with the advance of the dry season. Keywords: Dust Storms, Aerosol properties, AERONET, Satellites, Indo-Gangetic Basin, Aerosol Radiative Forcing (ARF).

  15. Vertically Resolved Aerosol Optical Properties over the ARM SGP Site

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Jonsson, H.; Strawa, A.; Provencal, B.; Covert, D.; Arnott, P.; Bucholtz, A.; Pilewskie, P.; Pommier, J.; Rissman, T.

    2003-01-01

    In order to meet one of its goals - to relate observations of radiative fluxes and radiances to the atmospheric composition - the Department of Energy's Atmospheric Radiation Measurement (ARM) program has pursued measurements and modeling activities that attempt to determine how aerosols impact atmospheric radiative transfer, both directly and indirectly. However, significant discrepancies between aerosol properties measured in situ or remotely remain. To this end, the ARM program will conduct an Aerosol Intensive Operational Period (IOP) in May 2003 at the ARM Southern Great Plains (SGP) site in north central Oklahoma. The IOP involves airborne measurements from two airplanes over the heavily instrumented SGP site. We will give an overview of early airborne results obtained aboard Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. The aircraft will carry instrumentation to perform in-situ measurements of aerosol absorption, scattering, extinction and particle size including such novel techniques as the photoacoustic and cavity ring-down methods. Aerosol optical depth and extinction will be measured with the NASA Ames Airborne Tracking 14-channel sunphotometer. Furthermore up- and downwelling solar (broadband and spectral) and infrared radiation will be measured using three different instruments. The up-looking radiation instruments will be mounted on a newly developed stabilized platform, which will keep the instruments level up to aircraft pitch and roll angles of 10 degrees. Additional effort will be directed toward measurement of cloud condensation nucleus concentration as a function of supersaturation and relating CCN concentration to aerosol composition and size distribution. This relation is central to description of the aerosol indirect effect.

  16. Vertical distribution of dimethylsulfide, sulfur dioxide, aerosol ions, and radon over the northeast Pacific Ocean

    NASA Technical Reports Server (NTRS)

    Andreae, M. O.; Berresheim, H.; Andreae, T. W.; Kritz, M. A.; Bates, T. S.

    1988-01-01

    The vertical distributions, in temperate latitudes, of dimethylsulfide (DMS), SO2, radon, methanesulfonate (MSA), nonsea-salt sulfate (nss-sulfate), and aerosol Na(+), NH4(+), and NO(-) ions were determined in samples collected by an aircraft over the northeast Pacific Ocean during May 3-12, 1985. DMS was also determined in surface seawater. It was found that DMS concentrations, both in seawater and in the atmospheric boundary layer, were significantly lower than the values reported previously for subtropical and tropical regions, reflecting the seasonal variability in the temperate North Pacific. The vertical profiles of DMS, MSA, SO2, and nss-sulfate were found to be strongly dependent on the convective stability of the atmosphere and on air mass origin. Biogenic sulfur emissions could account for most of the sulfur budget in the boundary layer, while the long-range transport of continentally derived air masses was mainly responsible for the elevated levels of both SO2 and nss-sulfate in the free troposphere.

  17. Profile of heating rate due to aerosols using lidar and skyradiometer in SKYNET Hefei site

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Liu, D.; Xie, C.

    2015-12-01

    Atmospheric aerosols have a significant impact on climate due to their important role in modifying atmosphere energy budget. On global scale, the direct radiative forcing is estimated to be in the range of -0.9 to -0.1 Wm-2 for aerosols [1]. Yet, these estimates are subject to very large uncertainties because of uncertainties in spatial and temporal variations of aerosols. At local scales, as aerosol properties can vary spatially and temporally, radiative forcing due to aerosols can be also very different and it can exceed the global value by an order of magnitude. Hence, it is very important to investigate aerosol loading, properties, and radiative forcing due to them in detail on local regions of climate significance. Haze and dust events in Hefei, China are explored by Lidar and Skyradiometer. Aerosol optical properties including the AOD, SSA, AAE and size distribution are analysed by using the SKYRAD.PACK [2] and presented in this paper. Furthermore, the radiative forcing due to aerosols and the heating rate in the ATM are also calculated using SBDART model [3]. The results are shown that the vertical heating rate is tightly related to aerosol profile. References: 1. IPCC. 2007. Climate Change 2007: The Physical Science Basic. Contribution of Working Group I Contribution to the Intergovernmental Panel on Climate Change Fourth Assessment Report. Solomon S, Qing D H, Manning M, et al. eds., Cambridge University Press, Cambridge, United Kingdom and New York, N Y, USA. 2. Nakajima, T., G. Tonna, R. Rao, Y. Kaufman, and B. Holben, 1996: Use of sky brightness measurements from ground for remote sensing of particulate poly dispersions, Appl. Opt., 35, 2672-2686. 3. Ricchiazzi et al 1998. SBDART: a research and teaching software tool for plane-parallel radiative transfer in the Earth's atmosphere,Bulletin of the American Meteorological Society,79,2101-2114.

  18. Measuring Aerosol Optical Depth (AOD) and Aerosol Profiles Simultaneously with a Camera Lidar

    NASA Astrophysics Data System (ADS)

    Barnes, John; Pipes, Robert; Sharma, Nimmi C. P.

    2016-06-01

    CLidar or camera lidar is a simple, inexpensive technique to measure nighttime tropospheric aerosol profiles. Stars in the raw data images used in the CLidar analysis can also be used to calculate aerosol optical depth simultaneously. A single star can be used with the Langley method or multiple star pairs can be used to reduce the error. The estimated error from data taken under clear sky conditions at Mauna Loa Observatory is approximately +/- 0.01.

  19. Temporal variability of aerosol optical thickness vertical distribution observed from CALIOP

    NASA Astrophysics Data System (ADS)

    Toth, Travis D.; Zhang, Jianglong; Campbell, James R.; Reid, Jeffrey S.; Vaughan, Mark A.

    2016-08-01

    Temporal variability in the vertical distribution of aerosol optical thickness (AOT) derived from the 0.532 µm aerosol extinction coefficient is described using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations over 8.5 years (June 2006 to December 2014). Temporal variability of CALIOP column-integrated AOT is largely consistent with total column AOT trends from several passive satellite sensors, such as the Moderate Resolution Imaging Spectroradiometer, Multiangle Imaging Spectroradiometer, and the Sea-viewing Wide Field-of-view Sensor. Globally, a 0.0002 AOT per year positive trend in deseasonalized CALIOP total column AOT for daytime conditions is attributed to corresponding changes in near-surface (i.e., 0.0-0.5 km or 0.5-1.0 km above ground level (agl)) aerosol particle loading, while a -0.0006 AOT per year trend during nighttime is attributed to elevated (i.e., 1.0-2.0 km or >2.0 km agl) aerosols. Regionally, increasing daytime CALIOP AOTs are found over Southern Africa and India, mostly due to changes in aerosol loading at the 1.0-2.0 km and 0.0-0.5 km agl layers, respectively. Decreasing daytime CALIOP AOTs are observed over Northern Africa, Eastern U.S., and South America (due mostly to elevated aerosol loading), while the negative CALIOP AOT trends found over Eastern China, Europe, and Western U.S. are due mostly to aerosol layers nearer the surface. To our knowledge, this study is the first to provide both a globally comprehensive estimation of the temporal variation in aerosol vertical distribution and an insight into passive sensor column AOT trends in the vertical domain.

  20. Local transport of vertically- and horizontally-emitted sodium oxide aerosols

    SciTech Connect

    Fields, D.E.; Miller, C.W.; Cooper, A.C.

    1986-01-01

    Liquid-metal cooled breeder reactors are expected to use large quantities of sodium or sodium-potassium alloy, and evaluation of the possible consequences of a liquid-metal fire, henceforth referred to as a sodium fire, is an important consideration. Of particular interest is the sodium aerosol concentration at the air intake ports that are used for reactor cooling, and which might suffer restricted flow under high aerosol concentrations. We have devised and applied a methodology for estimating the concentration of aerosols released vertically and horizontally from building surfaces and monitored at other building surface points. We have used this methodology to make calculations that indicate the time-development of aerosol build-up, and the maximum aerosol concentrations, at air intake ports. Building wake effects, momentum-driven plume rise, and density-driven plume rise are considered.

  1. The importance of vertical velocity variability for estimates of the indirect aerosol effects

    NASA Astrophysics Data System (ADS)

    West, R. E. L.; Stier, P.; Jones, A.; Johnson, C. E.; Mann, G. W.; Bellouin, N.; Partridge, D. G.; Kipling, Z.

    2014-06-01

    The activation of aerosols to form cloud droplets is dependent upon vertical velocities whose local variability is not typically resolved at the GCM grid scale. Consequently, it is necessary to represent the subgrid-scale variability of vertical velocity in the calculation of cloud droplet number concentration. This study uses the UK Chemistry and Aerosols community model (UKCA) within the Hadley Centre Global Environmental Model (HadGEM3), coupled for the first time to an explicit aerosol activation parameterisation, and hence known as UKCA-Activate. We explore the range of uncertainty in estimates of the indirect aerosol effects attributable to the choice of parameterisation of the subgrid-scale variability of vertical velocity in HadGEM-UKCA. Results of simulations demonstrate that the use of a characteristic vertical velocity cannot replicate results derived with a distribution of vertical velocities, and is to be discouraged in GCMs. This study focuses on the effect of the variance (σw2) of a Gaussian pdf (probability density function) of vertical velocity. Fixed values of σw (spanning the range measured in situ by nine flight campaigns found in the literature) and a configuration in which σw depends on turbulent kinetic energy are tested. Results from the mid-range fixed σw and TKE-based configurations both compare well with observed vertical velocity distributions and cloud droplet number concentrations. The radiative flux perturbation due to the total effects of anthropogenic aerosol is estimated at -1.9 W m-2 with σw = 0.1 m s-1, -2.1 W m-2 with σw derived from TKE, -2.25 W m-2 with σw = 0.4 m s-1, and -2.3 W m-2 with σw = 0.7 m s-1. The breadth of this range is 0.4 W m-2, which is comparable to a substantial fraction of the total diversity of current aerosol forcing estimates. Reducing the uncertainty in the parameterisation of σw would therefore be an important step towards reducing the uncertainty in estimates of the indirect aerosol effects

  2. Variation of the vertical distribution of Nabro volcano aerosol layers in the stratosphere observed by LIDAR

    NASA Astrophysics Data System (ADS)

    Noh, Young Min; Shin, Dong Ho; Müller, Detlef

    2017-04-01

    We present results of the vertical distribution variation of volcanic aerosol layers in the upper troposphere and lower stratosphere. The data were taken with our multiwavelength aerosol Raman lidar at Gwangju (35.10° N, 126.53° E), Korea. The volcanic ash particles and gases were released around 12 June 2011 during the eruption of the Nabro volcano (13.37° N, 41.7° E) in Eritrea, east Africa. Forward trajectory computations show that the volcanic aerosols were advected from North Africa to East Asia. The first measurement of the aerosol layer over Korea was on 19 June 2011. The aerosol layers appeared between 15 km and 17 km height asl (above sea level). The maximum value of the aerosol layer of the particle backscatter coefficient (1.5 ± 0.3 Mm-1 sr-1) and the linear particle depolarization ratio at 532 nm (2.2%) were observed at 16.4 km height asl. We continuously probed the upper troposphere and lower stratosphere for this volcanic aerosol layer during the following 6 months, until December 2011. The volcanic aerosol layer showed a single-peak of the particle backscatter coefficient and a comparably narrow vertical thickness at our observation site at the beginning of our observation period (i.e. comparably soon after the initial eruption period). After that initial period the vertical distribution of the plume changed. Multiple peaks and a comparably broad geometrical thickness developed with progressing observation time. The vertical thickness of the volcanic aerosol layer expanded up to 10 km by 3 August 2011. The linear particle depolarization ratios were larger in the lower part of the aerosol layer than the upper part of the aerosol layer. We observed a strong variation of the AOD (aerosol optical depth) in the first two months of our lidar observations. After these two months the AOD gradually decreased with time from September to December 20111 and the maximum particle backscatter coefficients consistently decreased. The corresponding e

  3. Beam Profile Monitor With Accurate Horizontal And Vertical Beam Profiles

    DOEpatents

    Havener, Charles C [Knoxville, TN; Al-Rejoub, Riad [Oak Ridge, TN

    2005-12-26

    A widely used scanner device that rotates a single helically shaped wire probe in and out of a particle beam at different beamline positions to give a pair of mutually perpendicular beam profiles is modified by the addition of a second wire probe. As a result, a pair of mutually perpendicular beam profiles is obtained at a first beamline position, and a second pair of mutually perpendicular beam profiles is obtained at a second beamline position. The simple modification not only provides more accurate beam profiles, but also provides a measurement of the beam divergence and quality in a single compact device.

  4. Computer simulation of an aircraft-based differential absorption and scattering system for retrieval of SO2 vertical profiles

    NASA Technical Reports Server (NTRS)

    Hoell, J. M., Jr.

    1975-01-01

    The feasibility of using the differential absorption and scattering technique from aircraft altitudes for remotely measuring the vertical distribution of SO2 was studied via a computer simulation. Particular care was taken in this simulation to use system parameters (i.e., laser energy, telescope size, etc.) which can be accommodated on an aircraft and can be realized with commercially available technology. The vertical molecular and aerosol profiles were chosen to simulate the types of profiles which might be experienced over a large city. Results are presented on the retrieval of the assumed SO2 profile which show the effects of systematic errors due to interfering gases and aerosols, as well as random errors due to shot noise in the return signal, detector and background noise, and instrument-generated noise.

  5. Evaluation of vertical profiles to design continuous descent approach procedure

    NASA Astrophysics Data System (ADS)

    Pradeep, Priyank

    The current research focuses on predictability, variability and operational feasibility aspect of Continuous Descent Approach (CDA), which is among the key concepts of the Next Generation Air Transportation System (NextGen). The idle-thrust CDA is a fuel economical, noise and emission abatement procedure, but requires increased separation to accommodate for variability and uncertainties in vertical and speed profiles of arriving aircraft. Although a considerable amount of researches have been devoted to the estimation of potential benefits of the CDA, only few have attempted to explain the predictability, variability and operational feasibility aspect of CDA. The analytical equations derived using flight dynamics and Base of Aircraft and Data (BADA) Total Energy Model (TEM) in this research gives insight into dependency of vertical profile of CDA on various factors like wind speed and gradient, weight, aircraft type and configuration, thrust settings, atmospheric factors (deviation from ISA (DISA), pressure and density of the air) and descent speed profile. Application of the derived equations to idle-thrust CDA gives an insight into sensitivity of its vertical profile to multiple factors. This suggests fixed geometric flight path angle (FPA) CDA has higher degree of predictability and lesser variability at the cost of non-idle and low thrust engine settings. However, with optimized design this impact can be overall minimized. The CDA simulations were performed using Future ATM Concept Evaluation Tool (FACET) based on radar-track and aircraft type data (BADA) of the real air-traffic to some of the busiest airports in the USA (ATL, SFO and New York Metroplex (JFK, EWR and LGA)). The statistical analysis of the vertical profiles of CDA shows 1) mean geometric FPAs derived from various simulated vertical profiles are consistently shallower than 3° glideslope angle and 2) high level of variability in vertical profiles of idle-thrust CDA even in absence of

  6. Measurements of the Vertical Structure of Aerosols and Clouds Over the Ocean Using Micro-Pulse LIDAR Systems

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; Spinhirne, James D.; Campbell, James R.; Berkoff, Timothy A.; Bates, David; Starr, David OC. (Technical Monitor)

    2001-01-01

    The determination of the vertical distribution of aerosols and clouds over the ocean is needed for accurate retrievals of ocean color from satellites observations. The presence of absorbing aerosol layers, especially at altitudes above the boundary layer, has been shown to influence the calculation of ocean color. Also, satellite data must be correctly screened for the presence of clouds, particularly cirrus, in order to measure ocean color. One instrument capable of providing this information is a lidar, which uses pulses of laser light to profile the vertical distribution of aerosol and cloud layers in the atmosphere. However, lidar systems prior to the 1990s were large, expensive, and not eye-safe which made them unsuitable for cruise deployments. During the 1990s the first small, autonomous, and eye-safe lidar system became available: the micro-pulse lidar, or MPL. The MPL is a compact and eye-safe lidar system capable of determining the range of aerosols and clouds by firing a short pulse of laser light (523 nm) and measuring the time-of-flight from pulse transmission to reception of a returned signal. The returned signal is a function of time, converted into range using the speed of light, and is proportional to the amount of light backscattered by atmospheric molecules (Rayleigh scattering), aerosols, and clouds. The MPL achieves ANSI eye-safe standards by sending laser pulses at low energy (micro-J) and expanding the beam to 20.32 cm in diameter. A fast pulse-repetition-frequency (2500 Hz) is used to achieve a good signal-to-noise, despite the low output energy. The MPL has a small field-of-view (< 100 micro-rad) and signals received with the instrument do not contain multiple scattering effects. The MPL has been used successfully at a number of long-term sites and also in several field experiments around the world.

  7. Retrieval of Aerosol Profiles using Multi Axis Differential Absorption Spectroscopy (MAX-DOAS)

    NASA Astrophysics Data System (ADS)

    Yilmaz, S.; Friess, U.; Apituley, A.; de Leeuw, G.; Platt, U.

    2009-04-01

    Multi Axis Differential Absorption Spectroscopy (MAX-DOAS) is a well established measurement technique to derive atmospheric trace gas profiles. Using MAX-DOAS measurements of trace gases with a known vertical profile, like the oxygen-dimer O4, it is possible to retrieve information on atmospheric aerosols. Based on the optimal estimation method, we have developed an algorithm which fits simultaneously measured O4 optical densities at several wavelengths and elevation angles to values simulated by a radiative transfer model. Retrieval parameters are aerosol extinction profile and optical properties like single scattering albedo, phase function and Angström exponent. In the scope of a joint research activity of the EU funded project EUSAAR (European Supersites for Atmospheric Aerosol Research) we have developed a new kind of DOAS instrument, which uses three miniature spectrometers to cover the near-ultraviolet to visible wavelength range (290-790nm), enabling to capture all absorption bands of the oxygen-dimer O4. Additionally, it is possible to point to any direction in the sky with a 2D telescope unit which is connected to the spectrometers via fiber optics. In May 2008, an intercomparison campaign with established aerosol measurement techniques took place in Cabauw/Netherlands, where simultaneous DOAS, LIDAR, Sun photometer and Nephelometer measurements were performed. We present first results of selected days from this period. The optical properties of aerosols retrieved by the DOAS measurement technique show very promising qualitative agreement with the established measurement techniques demonstrating the progress towards our goal of establishing the MAX-DOAS technique for retrieving optical properties of atmospheric aerosols. Quantitative comparison is ongoing.

  8. Seasonal variation of near surface black carbon and satellite derived vertical distribution of aerosols over a semi-arid station in India

    NASA Astrophysics Data System (ADS)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Shaik, Nazeer Hussain; Maraka, Vasudeva Reddy; Rajuru, Ramakrishna Reddy; Surendran Nair, Suresh Babu

    2017-02-01

    Extensive measurements of aerosol black carbon mass concentration (BC) and vertical profiles of atmospheric aerosols have been carried out using Aethalometer and CALIPSO level - 2 satellite data from December 2012 to November 2014 over a semi-arid station, Anantapur. We found a bimodal distribution in the mass concentrations of BC aerosols on a diurnal scale. A sharp peak was observed during morning rush hours (7:00 to 8:00 LT) almost an hour after the local sunrise. After which, a broad nocturnal peak was found during 21:00 to 22:00 LT. The seasonal mean BC concentrations (Mixed layer height (ML)) were found to be 3.45 ± 1.44 μg/m3 (676 ± 117 m), 2.55 ± 0.85 μg/m3 (1215 ± 190 m), 1.22 ± 0.31 μg/m3 (1134 ± 194 m) and 1.75 ± 0.70 μg/m3 (612 ± 135 m), during the winter, summer, monsoon and post-monsoon respectively. The vertical profiles of aerosol extinction coefficient and back scattering ratio profiles were derived from Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) showed a strong seasonal variation with aerosols mostly confined below 2 km during the post-monsoon and winter seasons whereas in the other two seasons, the aerosol layer expands beyond 6 km. Depolarization ratios (> 0.2) are higher during summer and monsoon at higher altitude regions demonstrate the presence of dust particles, which contribute to the large aerosol extinction at higher levels. These results are further supported by the backward trajectory cluster analysis.

  9. Saharan Mineral Dust Experiment SAMUM 2006: Airborne observations of dust particle properties and vertical dust profiles

    NASA Astrophysics Data System (ADS)

    Petzold, A.; Weinzierl, B.; Esselborn, M.; Fiebig, M.; Fix, A.; Kiemle, C.; Wirth, M.; Müller, D.; Wendisch, M.; Schuetz, L.; Kandler, K.; Kahn, R.; Wagner, F.; Pereira, S.; Virkkula, A.

    2006-12-01

    during the long-range transport events. First results will be presented on dust size distributions in several altitudes, dust optical properties and aerosol optical depths determined from HSRL and aerosol size distribution data. Vertical profiles of the dust mass loading will be discussed for the field sites of Zagora at the Saharan border and Evora in Portugal from the combination of ground-based and airborne measurements. This work is supported by the Deutsche Forschungsgemeinschaft DFG, the European Space Agency ESA and the European Fleet for Airborne research EUFAR.

  10. [A floating-dust case study based on the vertical distribution of aerosol optical properties].

    PubMed

    Wang, Yuan; Deng, Jun-Ying; Shi, Lan-Hong; Chen, Yong-Hang; Zhang, Qiang; Wang, Sheng; Xu, Ting-Ting

    2014-03-01

    The vertical distribution of aerosol 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 aerosol mainly existed below 2 km of height. The floating-dust aerosol 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 aerosol extinction coefficient first increased and then decreased during the floating-dust event. At the same time, the aerosol layer was constantly lifting. The CALIPSO data showed that a large number of small particles were suspended in air at a height of below 2 km, while the big particles always stayed near the ground (0-0.5 km). At the height of 2-10 km, there was only few aerosols; 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.

  11. LIDAR Measurements of the Vertical Distribution of Aerosol Optical and Physical Properties over Central Asia

    EPA Science Inventory

    The vertical structure of aerosol optical and physical properties was measured by Lidar in Eastern Kyrgyzstan, Central Asia, from June 2008 to May 2009. Lidar measurements were supplemented with surface-based measurements of PM2.5 and PM10 mass and chemical ...

  12. Evaluation of the aerosol vertical distribution in global aerosol models through comparison against CALIOP measurements: AeroCom phase II results

    NASA Astrophysics Data System (ADS)

    Koffi, Brigitte; Schulz, Michael; Bréon, François-Marie; Dentener, Frank; Steensen, Birthe Marie; Griesfeller, Jan; Winker, David; Balkanski, Yves; Bauer, Susanne E.; Bellouin, Nicolas; Berntsen, Terje; Bian, Huisheng; Chin, Mian; Diehl, Thomas; Easter, Richard; Ghan, Steven; Hauglustaine, Didier A.; Iversen, Trond; Kirkevâg, Alf; Liu, Xiaohong; Lohmann, Ulrike; Myhre, Gunnar; Rasch, Phil; Seland, Åyvind; Skeie, Ragnhild B.; Steenrod, Stephen D.; Stier, Philip; Tackett, Jason; Takemura, Toshihiko; Tsigaridis, Kostas; Vuolo, Maria Raffaella; Yoon, Jinho; Zhang, Kai

    2016-06-01

    The ability of 11 models in simulating the aerosol vertical distribution from regional to global scales, as part of the second phase of the AeroCom model intercomparison initiative (AeroCom II), is assessed and compared to results of the first phase. The evaluation is performed using a global monthly gridded data set of aerosol extinction profiles built for this purpose from the CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) Layer Product 3.01. Results over 12 subcontinental regions show that five models improved, whereas three degraded in reproducing the interregional variability in Zα0-6 km, the mean extinction height diagnostic, as computed from the CALIOP aerosol profiles over the 0-6 km altitude range for each studied region and season. While the models' performance remains highly variable, the simulation of the timing of the Zα0-6 km peak season has also improved for all but two models from AeroCom Phase I to Phase II. The biases in Zα0-6 km are smaller in all regions except Central Atlantic, East Asia, and North and South Africa. Most of the models now underestimate Zα0-6 km over land, notably in the dust and biomass burning regions in Asia and Africa. At global scale, the AeroCom II models better reproduce the Zα0-6 km latitudinal variability over ocean than over land. Hypotheses for the performance and evolution of the individual models and for the intermodel diversity are discussed. We also provide an analysis of the CALIOP limitations and uncertainties contributing to the differences between the simulations and observations.

  13. Vertical distribution of aerosol number concentration in the troposphere over Siberia derived from airborne in-situ measurements

    NASA Astrophysics Data System (ADS)

    Arshinov, Mikhail Yu.; Belan, Boris D.; Paris, Jean-Daniel; Machida, Toshinobu; Kozlov, Alexandr; Malyskin, Sergei; Simonenkov, Denis; Davydov, Denis; Fofonov, Alexandr

    2016-04-01

    Knowledge of the vertical distribution of aerosols particles is very important when estimating aerosol radiative effects. To date there are a lot of research programs aimed to study aerosol vertical distribution, but only a few ones exist in such insufficiently explored region as Siberia. Monthly research flights and several extensive airborne campaigns carried out in recent years in Siberian troposphere allowed the vertical distribution of aerosol number concentration to be summarized. In-situ aerosol measurements were performed in a wide range of particle sizes by means of improved version of the Novosibirsk-type diffusional particle sizer and GRIMM aerosol spectrometer Model 1.109. The data on aerosol vertical distribution enabled input parameters for the empirical equation of Jaenicke (1993) to be derived for Siberian troposphere up to 7 km. Vertical distributions of aerosol number concentration in different size ranges averaged for the main seasons of the year will be presented. This work was supported by Interdisciplinary integration projects of the Siberian Branch of the Russian Academy of Science No. 35, No. 70 and No. 131; the Branch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5); and Russian Foundation for Basic Research (grant No. 14-05-00526). Jaenicke R. Tropospheric aerosols, in Aerosol-Cloud-Climate Interactions, edited by P.V. Hobs. -Academic Press, San Diego, CA, 1993.- P. 1-31.

  14. Aerosols and Precipitation Retrievals over Eureka by Remote Sensing: Validation of Space Based Profiling Retrievals

    NASA Astrophysics Data System (ADS)

    Chaubey, J. P.; O'Neill, N. T.; Hudak, D. R.; Rodriguez, P.; Ivanescu, L.; Eloranta, E.; Duck, T.

    2014-12-01

    Aerosols and precipitation are among the agents responsible for the ongoing changes in the Arctic climate and the hydrological cycle. The seasonal variations of Arctic aerosols (Arctic haze for e.g.) are linked to the transport efficiency as well as precipitation (wet) scavenging. Aside from affecting aerosol concentrations, precipitation is an important hydrological variable that affects the moisture budget of the atmosphere. Aerosols, in turn, influence the vertical distribution of clouds and this induces changes in the precipitation pattern. The spatial and temporal sparsity of precipitation measurements over the Arctic region means that satellite remote sensing techniques take on an importance that considerably exceeds their role south of the Arctic circle. Radar reflectivity and snow profiles from CloudSat (in support of cloud and precipitation analyses) and backscattering measurements from CALIOP (investigations of aerosol and small cloud particle properties) can be used to study Arctic winter clouds and precipitation and the role of aerosols in their formation. In this study we attempt to validate satellite-based profiling retrievals of precipitation parameters using AHSRL (Arctic High Spectral Resolution Lidar), CRL (CANDAC Raman Lidar) and MMCR (Milli-Meter Cloud Radar) profiles acquired at the PEARL high-Arctic site in Eureka (80 °N, 86 °W), Nunavut, Canada. As part of the process of validating the profiling retrievals we aspire to learn more about the mechanisms controlling aerosol, cloud and precipitation inter-dynamics. In addition, ground-based, high-frequency observations of precipitation will be used for characterizing precipitation totals as well as the conditional probability of the type of precipitation (rain or snow) and thus to help understand and validate comparable information extracted from the satellite retrievals. We also aim to characterize different particle types using AHSRL and CRL depolarization profiles, MMCR Doppler velocity

  15. Profiling aerosol optical, microphysical and hygroscopic properties in ambient conditions by combining in situ and remote sensing

    NASA Astrophysics Data System (ADS)

    Tsekeri, Alexandra; Amiridis, Vassilis; Marenco, Franco; Nenes, Athanasios; Marinou, Eleni; Solomos, Stavros; Rosenberg, Phil; Trembath, Jamie; Nott, Graeme J.; Allan, James; Le Breton, Michael; Bacak, Asan; Coe, Hugh; Percival, Carl; Mihalopoulos, Nikolaos

    2017-01-01

    We present the In situ/Remote sensing aerosol Retrieval Algorithm (IRRA) that combines airborne in situ and lidar remote sensing data to retrieve vertical profiles of ambient aerosol optical, microphysical and hygroscopic properties, employing the ISORROPIA II model for acquiring the particle hygroscopic growth. Here we apply the algorithm on data collected from the Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft during the ACEMED campaign in the Eastern Mediterranean. Vertical profiles of aerosol microphysical properties have been derived successfully for an aged smoke plume near the city of Thessaloniki with aerosol optical depth of ˜ 0.4 at 532 nm, single scattering albedos of ˜ 0.9-0.95 at 550 nm and typical lidar ratios for smoke of ˜ 60-80 sr at 532 nm. IRRA retrieves highly hydrated particles above land, with 55 and 80 % water volume content for ambient relative humidity of 80 and 90 %, respectively. The proposed methodology is highly advantageous for aerosol characterization in humid conditions and can find valuable applications in aerosol-cloud interaction schemes. Moreover, it can be used for the validation of active space-borne sensors, as is demonstrated here for the case of CALIPSO.

  16. Profiling structured beams using injected aerosols

    NASA Astrophysics Data System (ADS)

    Loh, N. D.; Starodub, Dmitri; Lomb, Lukas; Hampton, Christina Y.; Martin, Andrew V.; Sierra, Raymond G.; Barty, Anton; Aquila, Andrew; Schulz, Joachim; Steinbrener, Jan; Shoeman, Robert L.; Kassemeyer, Stephan; Bostedt, Christoph; Bozek, John; Epp, Sascha W.; Erk, Benjamin; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Rudek, Benedikt; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Hauser, Günther; Holl, Peter; Pedersoli, Emanuele; Liang, MengNing; Hunter, Mark S.; Gumprecht, Lars; Coppola, Nicola; Wunderer, Cornelia; Graafsman, Heinz; Maia, Filipe R. N. C.; Ekeberg, Tomas; Hantke, Max; Fleckenstein, Holger; Hirsemann, Helmut; Nass, Karol; White, Thomas A.; Tobias, Herbert J.; Farquar, George R.; Benner, W. Henry; Hau-Riege, Stefan; Reich, Christian; Hartmann, Andreas; Soltau, Heike; Marchesini, Stefano; Bajt, Sasa; Barthelmess, Miriam; Strueder, Lothar; Ullrich, Joachim; Bucksbaum, Philip; Hodgson, Keith O.; Frank, Mathias; Schlichting, Ilme; Chapman, Henry N.; Bogan, Michael J.

    2012-10-01

    Profiling structured beams produced by X-ray free-electron lasers (FELs) is crucial to both maximizing signal intensity for weakly scattering targets and interpreting their scattering patterns. Earlier ablative imprint studies describe how to infer the X-ray beam profile from the damage that an attenuated beam inflicts on a substrate. However, the beams in-situ profile is not directly accessible with imprint studies because the damage profile could be different from the actual beam profile. On the other hand, although a Shack-Hartmann sensor is capable of in-situ profiling, its lenses may be quickly damaged at the intense focus of hard X-ray FEL beams. We describe a new approach that probes the in-situ morphology of the intense FEL focus. By studying the translations in diffraction patterns from an ensemble of randomly injected sub-micron latex spheres, we were able to determine the non-Gaussian nature of the intense FEL beam at the Linac Coherent Light Source (SLAC National Laboratory) near the FEL focus. We discuss an experimental application of such a beam-profiling technique, and the limitations we need to overcome before it can be widely applied.

  17. Retrievals of Profiles of Fine And Coarse Aerosols Using Lidar And Radiometric Space Measurements

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram; Tanre, Didier; Leon, Jean-Francois; Pelon, Jacques; Lau, William K. M. (Technical Monitor)

    2002-01-01

    In couple of years we expect the launch of the CALIPSO lidar spaceborne mission designed to observe aerosols and clouds. CALIPSO will collect profiles of the lidar attenuated backscattering coefficients in two spectral wavelengths (0.53 and 1.06 microns). Observations are provided along the track of the satellite around the globe from pole to pole. The attenuated backscattering coefficients are sensitive to the vertical distribution of aerosol particles, their shape and size. However the information is insufficient to be mapped into unique aerosol physical properties and vertical distribution. Infinite number of physical solutions can reconstruct the same two wavelength backscattered profile measured from space. CALIPSO will fly in formation with the Aqua satellite and the MODIS spectro-radiometer on board. Spectral radiances measured by MODIS in six channels between 0.55 and 2.13 microns simultaneously with the CALIPSO observations can constrain the solutions and resolve this ambiguity, albeit under some assumptions. In this paper we describe the inversion method and apply it to aircraft lidar and MODIS data collected over a dust storm off the coast of West Africa during the SHADE experiment. It is shown that the product of the single scattering albedo, omega, and the phase function, P, for backscattering can be retrieved from the synergism between measurements avoiding a priori hypotheses required for inverting lidar measurements alone. The resultant value of (omega)P(180 deg.) = 0.016/sr are significantly different from what is expected using Mie theory, but are in good agreement with recent results obtained from lidar observations of dust episodes. The inversion is robust in the presence of noise of 10% and 20% in the lidar signal in the 0.53 and 1.06 pm channels respectively. Calibration errors of the lidar of 5 to 10% can cause an error in optical thickness of 20 to 40% respectively in the tested cases. The lidar calibration errors cause degradation in the

  18. Measurements of stratospheric volcanic aerosol optical depth from NOAA TIROS Observational Vertical Sounder (TOVS) observations

    NASA Astrophysics Data System (ADS)

    Pierangelo, CléMence; ChéDin, Alain; Chazette, Patrick

    2004-02-01

    We show that the infrared optical depth of stratospheric volcanic aerosols produced by the eruption of Mount Pinatubo in June 1991 may be retrieved from the observations of the High-Resolution Infrared Radiation Sounder (HIRS-2) on board the polar meteorological satellites of the National Oceanic and Atmospheric Administration (NOAA). Evolution of the concentration in time and in space, in particular the migration of the aerosols from the tropics to the Northern and Southern Hemispheres, is found to be consistent with our knowledge of the consequences of this eruption. The method relies on the analysis of the differences between the satellite observations and simulations from an aerosol-free radiative transfer model using collocated radiosonde data as the prime input. Thus aerosol optical depths are retrieved directly without making assumptions about the aerosol size distribution or absorption coefficient. The aerosol optical depths reached a maximum in August 1991 in the tropical zone (0.055 at 8.3 μm, 0.03 at 4.0 μm, and 0.02 at 11.1 μm). The peak occurred in November 1991 in the southern midlatitudes and in March/April 1992 in the northern midlatitudes. A reanalysis of the almost 25 year archive of NOAA TIROS-N Operational Vertical Sounder (TOVS) observations holds considerable promise for improved knowledge of the atmosphere loading in volcanic aerosols.

  19. In Situ Aerosol Profile Measurements and Comparisons with SAGE 3 Aerosol Extinction and Surface Area Profiles at 68 deg North

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Under funding from this proposal three in situ profile measurements of stratospheric sulfate aerosol and ozone were completed from balloon-borne platforms. The measured quantities are aerosol size resolved number concentration and ozone. The one derived product is aerosol size distribution, from which aerosol moments, such as surface area, volume, and extinction can be calculated for comparison with SAGE III measurements and SAGE III derived products, such as surface area. The analysis of these profiles and comparison with SAGE III extinction measurements and SAGE III derived surface areas are provided in Yongxiao (2005), which comprised the research thesis component of Mr. Jian Yongxiao's M.S. degree in Atmospheric Science at the University of Wyoming. In addition analysis continues on using principal component analysis (PCA) to derive aerosol surface area from the 9 wavelength extinction measurements available from SAGE III. Ths paper will present PCA components to calculate surface area from SAGE III measurements and compare these derived surface areas with those available directly from in situ size distribution measurements, as well as surface areas which would be derived from PCA and Thomason's algorithm applied to the four wavelength SAGE II extinction measurements.

  20. Vertically resolved chemical characteristics and sources of submicron aerosols measured on a Tall Tower in a suburban area near Denver, Colorado in winter

    NASA Astrophysics Data System (ADS)

    Öztürk, F.; Bahreini, R.; Wagner, N. L.; Dubé, W. P.; Young, C. J.; Brown, S. S.; Brock, C. A.; Ulbrich, I. M.; Jimenez, J. L.; Cooper, O. R.; Middlebrook, A. M.

    2013-12-01

    Nitrogen, Aerosol Composition, and Halogens on a Tall Tower study was conducted at the Boulder Atmospheric Observatory in Colorado during February-March 2011. A compact time-of-flight aerosol mass spectrometer was installed in a moving carriage on the tower, obtaining vertical profiles of submicron nonrefractory aerosol mass concentrations (PM1nr) from 0-265 m above ground level. The average PM1nr was 4.6 ± 5.7 µg/m3, with average contributions of nitrate, organics, sulfate, ammonium, and chloride of 35%, 26%, 20%, 17%, and 1%, respectively. Positive Matrix Factorization analysis of the organic aerosol (OA) mass spectra indicated that average contributions of oxygenated organic aerosol (OOA)-I, OOA-II, and hydrocarbon-like organic aerosol (surrogates for aged and fresh secondary OA and primary OA, respectively) to OA mass were 52%, 32%, and 16%, respectively. There was considerable variability in the vertical profiles of aerosol mass loading and composition, especially at the lowest heights. Below 40 m, the highest PM1nr concentrations were composed of mostly nitrate (30-46%) and were associated with winds from the northeast where there are large agricultural facilities. When winds were southerly, PM1nr mass distributions near the surface had small, fresh OA, indicating the influence of nearby Denver urban emissions at the site. The largest contribution to OA mass at these heights was OOA-II (~43%). Between 40 and 120 m, trajectory cluster analysis indicated that during high-altitude long-range transport events, daytime aerosol composition was dominated by sulfate, whereas during low-altitude transport events, the contributions of sulfate, nitrate, and OA were comparable. OOA-I contributed the most (53-68%) to OA mass at these tower heights.

  1. Tethered balloon-borne aerosol measurements: seasonal and vertical variations of aerosol constituents over Syowa Station, Antarctica

    NASA Astrophysics Data System (ADS)

    Hara, K.; Osada, K.; Yamanouchi, T.

    2013-09-01

    Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica, during the 46th Japanese Antarctic expedition (2005-2006). Direct aerosol sampling was operated from near the surface to the lower free troposphere (approximately 2500 m) using a balloon-borne aerosol impactor. Individual aerosol particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Seasonal and vertical features of aerosol constituents and their mixing states were investigated. Results show that sulfate particles were predominant in the boundary layer and lower free troposphere in summer, whereas sea-salt particles were predominant during winter through spring. Minerals, MgSO4, and sulfate containing K were identified as minor aerosol constituents in both boundary layer and free troposphere over Syowa Station. Although sea-salt particles were predominant during winter through spring, the relative abundance of sulfate particles increased in the boundary layer when air masses fell from the free troposphere over the Antarctic coast and continent. Sea-salt particles were modified considerably through heterogeneous reactions with SO42- CH3SO3- and their precursors during summer, and were modified slightly through heterogeneous reactions with NO3- and its precursors. During winter through spring, sea-salt modification was insignificant, particularly in the cases of high relative abundance of sea-salt particles and higher number concentrations. In August, NO3- and its precursors contributed greatly to sea-salt modification over Syowa Station. Because of the occurrence of sea-salt fractionation on sea ice, Mg-rich sea-salt particles were identified during the months of April through November. In contrast, Mg-free sea-salt particles and slightly Mg-rich sea-salt particles coexisted in the lower troposphere during summer. Thereby, Mg separation can proceed by sea-salt fractionation during summer in Antarctic regions.

  2. Tethered balloon-borne aerosol measurements: seasonal and vertical variations of aerosol constituents over Syowa Station, Antarctica

    NASA Astrophysics Data System (ADS)

    Hara, K.; Osada, K.; Yamanouchi, T.

    2013-03-01

    Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica during the 46th Japanese Antarctic expedition (2005-2006). Direct aerosol sampling was operated from near the surface to the lower free troposphere (approximately 2500 m) using a balloon-borne aerosol impactor. Individual aerosol particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Seasonal and vertical features of aerosol constituents and their mixing states were investigated. Results show that sulfate particles were dominant in the boundary layer and lower free troposphere in the summer, whereas sea-salt particles were dominant during winter-spring. Minerals, MgSO4, and sulfate containing K were identified as minor aerosol constituents in both boundary layer and free troposphere over Syowa Station. Although sea-salt particles were dominant during winter-spring, the relative abundance of sulfate particles increased in the boundary layer when air masses fell from the free troposphere over the Antarctic coast and continent. Sea-salt particles were modified considerably through heterogeneous reactions with SO42-, CH3SO3-, and their precursors during the summer, and were modified slightly through heterogeneous reactions with NO3- and its precursors. During winter-spring, sea-salt modification was insignificant, particularly in the cases of high relative abundance of sea-salt particles and higher number concentrations. In August, NO3- and its precursors contributed greatly to sea-salt modification over Syowa Station. Because of the occurrence of sea-salt fractionation on sea-ice, Mg-rich sea-salt particles were identified during April-November. In contrast, Mg-free sea-salt particles and slightly Mg-rich sea-salt particles co-existed in the lower troposphere during summer. Thereby, Mg separation can proceed by sea-salt fractionation during summer in Antarctic regions.

  3. Measurement and Modeling of Vertically Resolved Aerosol Optical Properties and Radiative Fluxes Over the ARM SGP Site

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Arnott, P.; Bucholtz, A.; Colarco, P.; Covert, D.; Eilers, J.; Elleman, R.; Ferrare, R.; Flagan, R.; Jonsson, H.

    2003-01-01

    In order to meet one of its goals - to relate observations of radiative fluxes and radiances to the atmospheric composition - the Department of Energy's Atmospheric Radiation Measurement (ARM) program has pursued measurements and modeling activities that attempt to determine how aerosols impact atmospheric radiative transfer, both directly and indirectly. However, significant discrepancies between aerosol properties measured in situ or remotely remain. One of the objectives of the Aerosol Intensive Operational Period (TOP) conducted by ARM in May 2003 at the ARM Southern Great Plains (SGP) site in north central Oklahoma was to examine and hopefully reduce these differences. The IOP involved airborne measurements from two airplanes over the heavily instrumented SGP site. We give an overview of airborne results obtained aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft. The Twin Otter performed 16 research flights over the SGP site. The aircraft carried instrumentation to perform in-situ measurements of aerosol absorption, scattering, extinction and particle size. This included such novel techniques as the photoacoustic and cavity ring-down methods for in-situ absorption (675 nm) and extinction (675 and 1550 nm) and a new multiwavelength, filter-based absorption photometer (467, 530, 660 nm). A newly developed instrument measured cloud condensation nucleus concentration (CCN) concentrations at two supersaturation levels. Aerosol optical depth and extinction (354-2139 nm) were measured with the NASA Ames Airborne Tracking 14-channel sunphotometer. Furthermore, up-and downwelling solar (broadband and spectral) and infrared radiation were measured using seven individual radiometers. Three up-looking radiometers werer mounted on a newly developed stabilized platform, keeping the instruments level up to aircraft pitch and roll angles of approximately 10(exp 0). This resulted in unprecedented continuous vertical profiles

  4. Relating Aerosol Profile and Column Measurements to Surface Concentrations: What Have We Learned from Discover-AQ?

    NASA Astrophysics Data System (ADS)

    Hoff, R. M.

    2014-12-01

    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 Aerosol 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 aerosol optical depth challenging, but upward looking columns of aerosol 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 layer heights and dominance of nitrate and organic aerosols made the AOD fields less predictive of PM2.5. In California and Colorado, hydration of the aerosol varied dramatically with aerosol type (especially smoke and dust) and revealed that without an understanding of the degree of aerosol hydration with aerosol 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.

  5. Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall.

    PubMed

    Wang, Jian; Krejci, Radovan; Giangrande, Scott; Kuang, Chongai; Barbosa, Henrique M J; Brito, Joel; Carbone, Samara; Chi, Xuguang; Comstock, Jennifer; Ditas, Florian; Lavric, Jost; Manninen, Hanna E; Mei, Fan; Moran-Zuloaga, Daniel; Pöhlker, Christopher; Pöhlker, Mira L; Saturno, Jorge; Schmid, Beat; Souza, Rodrigo A F; Springston, Stephen R; Tomlinson, Jason M; Toto, Tami; Walter, David; Wimmer, Daniela; Smith, James N; Kulmala, Markku; Machado, Luiz A T; Artaxo, Paulo; Andreae, Meinrat O; Petäjä, Tuukka; Martin, Scot T

    2016-11-17

    The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin (for example, ref. 2) and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear. Here we present aircraft- and ground-based measurements under clean conditions during the wet season in the central Amazon basin. We find that high concentrations of small aerosol particles (with diameters of less than 50 nanometres) in the lower free troposphere are transported from the free troposphere into the boundary layer during precipitation events by strong convective downdrafts and weaker downward motions in the trailing stratiform region. This rapid vertical transport can help to maintain the population of particles in the pristine Amazon boundary layer, and may therefore influence cloud properties and climate under natural conditions.

  6. Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Krejci, Radovan; Giangrande, Scott; Kuang, Chongai; Barbosa, Henrique M. J.; Brito, Joel; Carbone, Samara; Chi, Xuguang; Comstock, Jennifer; Ditas, Florian; Lavric, Jost; Manninen, Hanna E.; Mei, Fan; Moran-Zuloaga, Daniel; Pöhlker, Christopher; Pöhlker, Mira L.; Saturno, Jorge; Schmid, Beat; Souza, Rodrigo A. F.; Springston, Stephen R.; Tomlinson, Jason M.; Toto, Tami; Walter, David; Wimmer, Daniela; Smith, James N.; Kulmala, Markku; Machado, Luiz A. T.; Artaxo, Paulo; Andreae, Meinrat O.; Petäjä, Tuukka; Martin, Scot T.

    2016-11-01

    The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin (for example, ref. 2) and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear. Here we present aircraft- and ground-based measurements under clean conditions during the wet season in the central Amazon basin. We find that high concentrations of small aerosol particles (with diameters of less than 50 nanometres) in the lower free troposphere are transported from the free troposphere into the boundary layer during precipitation events by strong convective downdrafts and weaker downward motions in the trailing stratiform region. This rapid vertical transport can help to maintain the population of particles in the pristine Amazon boundary layer, and may therefore influence cloud properties and climate under natural conditions.

  7. Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall

    SciTech Connect

    Wang, Jian; Krejci, Radovan; Giangrande, Scott; Kuang, Chongai; Barbosa, Henrique M. J.; Brito, Joel; Carbone, Samara; Chi, Xuguang; Comstock, Jennifer; Ditas, Florian; Lavric, Jost; Manninen, Hanna E.; Mei, Fan; Moran-Zuloaga, Daniel; Pöhlker, Christopher; Pöhlker, Mira L.; Saturno, Jorge; Schmid, Beat; Souza, Rodrigo A. F.; Springston, Stephen R.; Tomlinson, Jason M.; Toto, Tami; Walter, David; Wimmer, Daniela; Smith, James N.; Kulmala, Markku; Machado, Luiz A. T.; Artaxo, Paulo; Andreae, Meinrat O.; Petäjä, Tuukka; Martin, Scot T.

    2016-10-24

    The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear. Here we present aircraft- and ground-based measurements under clean conditions during the wet season in the central Amazon basin. We find that high concentrations of small aerosol particles (with diameters of less than 50 nanometres) in the lower free troposphere are transported from the free troposphere into the boundary layer during precipitation events by strong convective downdrafts and weaker downward motions in the trailing stratiform region. Lastly, this rapid vertical transport can help to maintain the population of particles in the pristine Amazon boundary layer, and may therefore influence cloud properties and climate under natural conditions.

  8. Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall

    DOE PAGES

    Wang, Jian; Krejci, Radovan; Giangrande, Scott; ...

    2016-10-24

    The nucleation of atmospheric vapours is an important source of new aerosol particles that can subsequently grow to form cloud condensation nuclei in the atmosphere. Most field studies of atmospheric aerosols over continents are influenced by atmospheric vapours of anthropogenic origin and, in consequence, aerosol processes in pristine, terrestrial environments remain poorly understood. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions, but the origin of small aerosol particles that grow into cloud condensation nuclei in the Amazon boundary layer remains unclear. Here we present aircraft- andmore » ground-based measurements under clean conditions during the wet season in the central Amazon basin. We find that high concentrations of small aerosol particles (with diameters of less than 50 nanometres) in the lower free troposphere are transported from the free troposphere into the boundary layer during precipitation events by strong convective downdrafts and weaker downward motions in the trailing stratiform region. Lastly, this rapid vertical transport can help to maintain the population of particles in the pristine Amazon boundary layer, and may therefore influence cloud properties and climate under natural conditions.« less

  9. TOMS Validation Based on Profiles of Aerosol Properties in the Lower Troposphere as Obtained with Light Aircraft Systems

    NASA Technical Reports Server (NTRS)

    Prospero, Joseph M.; Maring, Hal; Savoie, Dennis

    2003-01-01

    The goal of the University of Miami Aerosol Group (UMAG) in this project was to make measurements of vertical profiles of aerosol properties and aerosol optical depth using a light aircraft. The UMAG developed a light aircraft aerosol package (LAAP) that was used in light aircraft (Cessna 172) during the Puerto Rico Dust Experiment (PRIDE). This field campaign took place on Puerto Rico during July 2000. Design details and results from the use of the LAAP were presented at TOMS Science team meetings on April 1998, April 1999, and May 2000. Results from the LAAP collected during the PRIDE Experiment were presented at the Fall Meeting of the American Geophysical Union, December 2000. Some of the results from the LAAP collected during the PRIDE Experiment have been accepted for publication in the Journal of Geophysical Research in a "topical section" made up of papers from the PRIDE Program.

  10. Statistics of aerosol extinction coefficient profiles and optical depth using lidar measurement over Lanzhou, China since 2005-2008

    NASA Astrophysics Data System (ADS)

    Cao, X.; Wang, Z.; Tian, P.; Wang, J.; Zhang, L.; Quan, X.

    2013-06-01

    The aerosol extinction coefficient profiles and optical depth over Lanzhou in China were observed under no precipitation and dust free condition using the micropulse lidar CE370-2 from September 2005 to July 2008. The statistics of the variations of monthly average aerosol optical depth (AOD) and daily average AOD, frequency distribution of daily average AOD, and the seasonal variation of aerosol vertical distribution were analyzed based on the observation data. The results showed that the daily average AOD of Main Observatory and City Observatory was 87.8% and 78.2% ranged below 0.4 respectively with similar frequency distribution patterns. The AOD in autumn and winter were larger than that in spring and summer, and AOD in suburb was in certain extent smaller than that in city of Lanzhou. Aerosol existed in the layer below 4km, and its extinction coefficient decreased with increasing of height.

  11. The GAW Aerosol Lidar Observation Network (GALION) as a source of near-real time aerosol profile data for model evaluation and assimilation

    NASA Astrophysics Data System (ADS)

    Hoff, R. M.; Pappalardo, G.

    2010-12-01

    In 2007, the WMO Global Atmospheric Watch’s Science Advisory Group on Aerosols described a global network of lidar networks called GAW Aerosol Lidar Observation Network (GALION). GALION has a purpose of providing expanded coverage of aerosol observations for climate and air quality use. Comprised of networks in Asia (AD-NET), Europe (EARLINET and CIS-LINET), North America (CREST and CORALNET), South America (ALINE) and with contribution from global networks such as MPLNET and NDACC, the collaboration provides a unique capability to define aerosol profiles in the vertical. GALION is designed to supplement existing ground-based and column profiling (AERONET, PHOTONS, SKYNET, GAWPFR) stations. In September 2010, GALION held its second workshop and one component of discussion focussed how the network would integrate into model needs. GALION partners have contributed to the Sand and Dust Storm Warning and Analysis System (SDS-WAS) and to assimilation in models such as DREAM. This paper will present the conclusions of those discussions and how these observations can fit into a global model analysis framework. Questions of availability, latency, and aerosol parameters that might be ingested into models will be discussed. An example of where EARLINET and GALION have contributed in near-real time observations was the suite of measurements during the Eyjafjallajokull eruption in Iceland and its impact on European air travel. Lessons learned from this experience will be discussed.

  12. Vertical soil profiling using a galvanic contact resistivity scanning approach.

    PubMed

    Pan, Luan; Adamchuk, Viacheslav I; Prasher, Shiv; Gebbers, Robin; Taylor, Richard S; Dabas, Michel

    2014-07-23

    Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function. To assess vertical soil profiles, many modern instruments use multiple transmitter-receiver pairs. Alternatively, vertical electrical sounding can be used to measure changes in apparent soil electrical conductivity with depth at a specific location. This paper examines the possibility for the assessment of soil profiles using a dynamic surface galvanic contact resistivity scanning approach, with transmitting and receiving electrodes configured in an equatorial dipole-dipole array. An automated scanner system was developed and tested in agricultural fields with different soil profiles. While operating in the field, the distance between current injecting and measuring pairs of rolling electrodes was varied continuously from 40 to 190 cm. The preliminary evaluation included a comparison of scan results from 20 locations to shallow (less than 1.2 m deep) soil profiles and to a two-layer soil profile model defined using an electromagnetic induction instrument.

  13. Vertical Soil Profiling Using a Galvanic Contact Resistivity Scanning Approach

    PubMed Central

    Pan, Luan; Adamchuk, Viacheslav I.; Prasher, Shiv; Gebbers, Robin; Taylor, Richard S.; Dabas, Michel

    2014-01-01

    Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function. To assess vertical soil profiles, many modern instruments use multiple transmitter-receiver pairs. Alternatively, vertical electrical sounding can be used to measure changes in apparent soil electrical conductivity with depth at a specific location. This paper examines the possibility for the assessment of soil profiles using a dynamic surface galvanic contact resistivity scanning approach, with transmitting and receiving electrodes configured in an equatorial dipole-dipole array. An automated scanner system was developed and tested in agricultural fields with different soil profiles. While operating in the field, the distance between current injecting and measuring pairs of rolling electrodes was varied continuously from 40 to 190 cm. The preliminary evaluation included a comparison of scan results from 20 locations to shallow (less than 1.2 m deep) soil profiles and to a two-layer soil profile model defined using an electromagnetic induction instrument. PMID:25057135

  14. Vertical profile of atmospheric conductivity that matches Schumann resonance observations.

    PubMed

    Nickolaenko, Alexander P; Galuk, Yuri P; Hayakawa, Masashi

    2016-01-01

    We introduce the vertical profile of atmospheric conductivity in the range from 2 to 98 km. The propagation constant of extremely low frequency (ELF) radio waves was computed for this profile by using the full wave solution. A high correspondence is demonstrated of the data thus obtained to the conventional standard heuristic model of ELF propagation constant derived from the Schumann resonance records performed all over the world. We also suggest the conductivity profiles for the ambient day and ambient night conditions. The full wave solution technique was applied for obtaining the corresponding frequency dependence of propagation constant relevant to these profiles. By using these propagation constants, we computed the power spectra of Schumann resonance in the vertical electric field component for the uniform global distribution of thunderstorms and demonstrate their close similarity in all the models. We also demonstrate a strong correspondence between the wave attenuation rate obtained for these conductivity profiles and the measured ones by using the ELF radio transmissions.

  15. What controls the vertical distribution of aerosol? Relationships between process sensitivity in HadGEM3–UKCA and inter-model variation from AeroCom Phase II

    SciTech Connect

    Kipling, Zak; Stier, Philip; Johnson, Colin E.; Mann, Graham W.; Bellouin, Nicolas; Bauer, Susanne E.; Bergman, Tommi; Chin, Mian; Diehl, Thomas; Ghan, Steven J.; Iversen, Trond; Kirkevag, Alf; Kokkola, Harri; Liu, Xiaohong; Luo, Gan; van Noije, Twan; Pringle, Kirsty J.; von Salzen, Knut; Schulz, Michael; Seland, Oyvind; Skeie, Ragnhild B.; Takemura, Toshihiko; Tsigaridis, Kostas; Zhang, Kai

    2016-02-26

    The vertical profile of aerosol is important for its radiative effects, but weakly constrained by observations on the global scale, and highly variable among different models. To investigate the controlling factors in one particular model, we investigate the effects of individual processes in HadGEM3–UKCA and compare the resulting diversity of aerosol vertical profiles with the inter-model diversity from the AeroCom Phase II control experiment.

    In this way we show that (in this model at least) the vertical profile is controlled by a relatively small number of processes, although these vary among aerosol components and particle sizes. We also show that sufficiently coarse variations in these processes can produce a similar diversity to that among different models in terms of the global-mean profile and, to a lesser extent, the zonal-mean vertical position. However, there are features of certain models' profiles that cannot be reproduced, suggesting the influence of further structural differences between models.

    In HadGEM3–UKCA, convective transport is found to be very important in controlling the vertical profile of all aerosol components by mass. In-cloud scavenging is very important for all except mineral dust. Growth by condensation is important for sulfate and carbonaceous aerosol (along with aqueous oxidation for the former and ageing by soluble material for the latter). The vertical extent of biomass-burning emissions into the free troposphere is also important for the profile of carbonaceous aerosol. Boundary-layer mixing plays a dominant role for sea salt and mineral dust, which are emitted only from the surface. Dry deposition and below-cloud scavenging are important for the profile of mineral dust only.

    In this model, the microphysical processes of nucleation, condensation and coagulation dominate the vertical profile of the smallest particles by number (e.g. total CN > 3 nm), while the profiles of larger particles (e.g. CN

  16. What controls the vertical distribution of aerosol? Relationships between process sensitivity in HadGEM3–UKCA and inter-model variation from AeroCom Phase II

    DOE PAGES

    Kipling, Zak; Stier, Philip; Johnson, Colin E.; ...

    2016-02-26

    The vertical profile of aerosol is important for its radiative effects, but weakly constrained by observations on the global scale, and highly variable among different models. To investigate the controlling factors in one particular model, we investigate the effects of individual processes in HadGEM3–UKCA and compare the resulting diversity of aerosol vertical profiles with the inter-model diversity from the AeroCom Phase II control experiment. In this way we show that (in this model at least) the vertical profile is controlled by a relatively small number of processes, although these vary among aerosol components and particle sizes. We also show that sufficientlymore » coarse variations in these processes can produce a similar diversity to that among different models in terms of the global-mean profile and, to a lesser extent, the zonal-mean vertical position. However, there are features of certain models' profiles that cannot be reproduced, suggesting the influence of further structural differences between models. In HadGEM3–UKCA, convective transport is found to be very important in controlling the vertical profile of all aerosol components by mass. In-cloud scavenging is very important for all except mineral dust. Growth by condensation is important for sulfate and carbonaceous aerosol (along with aqueous oxidation for the former and ageing by soluble material for the latter). The vertical extent of biomass-burning emissions into the free troposphere is also important for the profile of carbonaceous aerosol. Boundary-layer mixing plays a dominant role for sea salt and mineral dust, which are emitted only from the surface. Dry deposition and below-cloud scavenging are important for the profile of mineral dust only. In this model, the microphysical processes of nucleation, condensation and coagulation dominate the vertical profile of the smallest particles by number (e.g. total CN > 3 nm), while the profiles of larger particles (e.g. CN > 100 nm) are

  17. Aerosol Profile Retrievals from Integrated Dual Wavelengths Space Lidar ESSP3-CENA and Spectral Radiance MODIS Data

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram; Mattoo, Shana; Tanre, Didier; Kleidman, Richard; Lau, William K. M. (Technical Monitor)

    2001-01-01

    The ESSP3-CENA space mission (formally PICASSO-CENA) will provide continues global observations with a two wavelength lidar. The attenuated backscattering coefficients measured by the lidar, have valuable information about the vertical distribution of aerosol particles and their sizes. However the information cannot be mapped into unique aerosol physical properties. Infinite number of physical solutions with different attenuations through the atmosphere can reconstruct the same two wavelength backscattered profile measured from space. Spectral radiance measured by MODIS simultaneously with the ESSP3 data can constrain the problem and resolve this ambiguity to a large extent. Sensitivity study shows that inversion of the integrated MODIS+ESSP3 data can derive the vertical profiles of the fine and coarse modes mixed in the same atmospheric column in the presence of moderate calibration uncertainties and electronic noise (approx. 10%). We shall present the sensitivity study and results from application of the technique to measurements in the SAFARI-2000 and SHADE experiments.

  18. Quality Screening Algorithms Implemented in the New CALIPSO Level 3 Aerosol Profile Product

    NASA Astrophysics Data System (ADS)

    Tackett, J. L.; Winker, D. M.; Getzewich, B. J.; Vaughan, M.

    2012-12-01

    Global observations of aerosol extinction profiles can improve the ability of climate models to properly account for aerosol radiative forcing in Earth's atmosphere. In response to this need, a new CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) level 3 aerosol profile product has been released which for the first time provides monthly, globally gridded and quality-screened aerosol extinction profiles within the troposphere for the entire 6-year mission. Level 3 aerosol extinction profiles are aggregated from CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) lidar extinction retrievals reported in the CALIPSO level 2 aerosol profile product onto an equal-angle grid after quality screening algorithms are applied to reduce occurrences of failed retrievals, misclassified aerosol, surface contamination, and spurious outliers. Implementation of these quality screening algorithms is a substantial value to aerosol modeling groups who desire high confidence datasets without having to independently develop quality screening metrics. Furthermore, quality screening is paramount to understand the scientific content of the resultant CALIPSO level 3 aerosol profile product since classification and retrieval errors in level 2 aerosol data may lead to misinterpretation of the distribution and optical properties of aerosol in the troposphere. This presentation summarizes the averaging and quality screening algorithms implemented in the CALIPSO level 3 aerosol profile product, provides rationale for their implementation, and discusses averaging and filtering differences unique to CALIPSO data compared to level 3 products aggregated from passive satellite measurements. Examples are given that illustrate the benefits of quality screening and the dangers of improper screening CALIPSO level 2 aerosol extinction data. Sensitivity study results are presented to highlight the impact of quality screening on final level 3 statistics. Since overlying cloud

  19. Measurements of profiles of aerosol/cloud in the lower atmosphere using a lidar system

    NASA Astrophysics Data System (ADS)

    Gasmi, Khaled

    2016-10-01

    Preliminary measurements of profiles of aerosol/cloud in the lower atmosphere using a homemade stationary groundbased lidar system will be presented. In addition, information on basic characteristics and performance of the lidar system will be provided. Aerosol/Cloud lidar system in monostatic coaxial configuration uses the fundamental (1064 nm) and the second harmonic (532 nm) of a pulsed solid state Nd:YAG laser to provide information on the relative concentration and spatial distribution of aerosol particles and cloud water droplets. Beam expander is used to reduce the laser beam divergence before to be transmitted into the atmosphere. In this study, high-resolution vertical profiles from the near ground up to 15 km altitude are obtained. A Newtonian telescope of diameter 400 mm with an adjustable field of view (FOV) is used to collect the elastic backscattered signal. A photomultiplier tube (PMT) is used for the 532 nm wavelength detection channel, while an avalanche photodiode (APD) is used for the 1064 nm wavelength detection channel. The optoelectronic detection channels use two similar very high frequency preamplification circuit. Data are acquired with a nominal spatial resolution of 7.5 m using a 12-bit 20 MHz analog-to-digital converter (ADC) for each channel. Many functions, such as, range determination, background subtraction, digitization, and averaging are performed by the receiver subsystem. In addition, spatial resolution and linear dynamic range were optimized during signal processing.

  20. Measurements of Sea Salt Aerosols in the Marine Boundary Layer and Free Troposphere: Vertical Transport and Chemical Transformation

    NASA Astrophysics Data System (ADS)

    Hudson, P. K.; Murphy, D. M.; Cziczo, D. J.; Thomson, D. S.

    2002-12-01

    During the Intercontinental Transport and Chemical Transformation (ITCT) mission (Monterey, CA, spring 2002) nearly 400,000 positive and negative mass spectra of single atmospheric aerosols were acquired using the PALMS (Particle Analysis by Laser Mass Spectrometry) instrument. The primary focus of the mission was to investigate the composition of air masses along the western coast of the United States. Of particular interest to the mission was to study the influence of anthropogenic emissions from Asia on aerosol composition. To accomplish these goals, the WP-3 aircraft, equipped with a suite of instruments including PALMS, covered a large spatial area flying from 0 - 8000 m altitude covering most of the western coastline from Canada to southern California including flights over the San Francisco and Los Angeles metropolitan areas. The in situ measurements of single particle aerosol mass spectra by PALMS allow for good spatial and vertical resolution of the aerosol composition. By observing the changes in aerosol composition as a function of altitude, the vertical transport of sea salt aerosols over marine and urban environments is examined. Using measurements of other chemical tracers along with the aerosol composition, the chemical processing of these aerosols during transport both vertically and inland can be discerned. These results add insight into the transport and chemical evolution of sea salt aerosol.

  1. Radial-vertical profiles of tropical cyclone derived from dropsondes

    NASA Astrophysics Data System (ADS)

    Ren, Yifang

    The scopes of this thesis research are two folds: the first one is to the construct the intensity-based composite radial-vertical profiles of tropical cyclones (TC) using GPS-based dropsonde observations and the second one is to identify the major deficiencies of Mathur vortices against the dropsonde composites of TCs. The intensity-based dropsonde composites of TCs advances our understanding of the dynamic and thermal structure of TCs of different intensity along the radial direction in and above the boundary layer where lies the devastating high wind that causes property damages and storm surges. The identification of the major deficiencies of Mathur vortices in representing the radial-vertical profiles of TC of different intensity helps to improve numerical predictions of TCs since most operational TC forecast models need to utilize bogus vortices, such as Mathur vortices, to initialize TC forecasts and simulations. We first screen all available GPS dropsonde data within and round 35 named TCs over the tropical Atlantic basin from 1996 to 2010 and pair them with TC parameters derived from the best-track data provided by the National Hurricane Center (NHC) and select 1149 dropsondes that have continuous coverage in the lower troposphere. The composite radial-vertical profiles of tangential wind speed, temperature, mixing ratio and humidity are based for each TC category ranging from "Tropical Storm" (TS) to "Hurricane Category 1" (H1) through "Hurricane Category 5" (H5). The key findings of the dropsonde composites are: (i) all TCs have the maximum tangential wind within 1 km above the ground and a distance of 1-2 times of the radius of maximum wind (RMW) at the surface; (ii) all TCs have a cold ring surrounding the warm core near the boundary layer at a distance of 1-3 times of the RMW and the cold ring structure gradually diminishes at a higher elevation where the warm core structure prevails along the radial direction; (iii) the existence of such shallow cold

  2. Aerosol interactions between the surface and the atmosphere: Urban fluxes, forest canopy vertical exchange, and wintertime urban patterns

    NASA Astrophysics Data System (ADS)

    Grivicke, Rasa

    Atmospheric aerosols play a major role in regional atmospheric chemistry and air quality, while on a global scale, aerosol processes continue to represent the largest source of uncertainty related to climate change. An important aspect of understanding the role of aerosols in these areas is to document the vertical exchange of aerosols with the surface in both urban and rural landscapes since the vertical exchange represents important sources and sinks of aerosols on regional and global scales. In this dissertation, investigation of aerosol dynamics is described for three separate field studies. First, urban eddy covariance flux measurements were made from a building rooftop in Mexico City using a quadrupole aerosol mass spectrometer (Q-AMS) to determine the fluxes of aerosol species to/from the urban landscape. Second, conditional sampling of fine particles in updrafts and downdrafts was performed above a pine forest in Colorado using a thermal desorption chemical ionization mass spectrometer (TD-CIMS) to investigate the relative strengths of sources and sinks for speciated aerosol in a forest environment. Third, the aerosol and gas phase pollutant patterns, measured in Boise, ID during wintertime inversion conditions, were analyzed with respect to the daily evolution of the planetary boundary layer depth and surface meteorological conditions. This dissertation describes the methods used for each of the three studies and summarizes the analysis of the results.

  3. Application of the CALIOP Layer Product to Evaluate the Vertical Distribution of Aerosols Estimated by Global Models: AeroCom Phase I Results

    NASA Technical Reports Server (NTRS)

    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

    2012-01-01

    The CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) layer product is used for a multimodel evaluation of the vertical distribution of aerosols. Annual and seasonal aerosol 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 (Aerosol Comparisons between Observations and Models) 2000 simulations. An extinction mean height 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 layer by its aerosol extinction coefficient. The mean extinction profiles derived from CALIOP layer 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.

  4. Application of the CALIOP Layer Product to Evaluate the Vertical Distribution of Aerosols Estimated by Global Models: AeroCom Phase I Results

    SciTech Connect

    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.

    2012-05-19

    The CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) layer product is used for a multimodel evaluation of the vertical distribution of aerosols. Annual and seasonal aerosol 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 (Aerosol Comparisons between Observations and Models) 2000 simulations. An extinction mean height 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 layer by its aerosol extinction coefficient. The mean extinction profiles derived from CALIOP layer 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.

  5. Vertical and Spatial Profiling of Arctic Black Carbon on the North Slope of Alaska 2015: Comparison of Model and Observation

    NASA Astrophysics Data System (ADS)

    Sedlacek, A. J., III; Feng, Y.; Biraud, S.; Springston, S. R.

    2015-12-01

    One of the major issues confronting aerosol climate simulations of the Arctic and Antarctic Cryospheres is the lack of detailed data on the vertical and spatial distribution of aerosols with which to test these models. This is due, in part, to the inherent difficulty of conducting such measurements in extreme environments. One class of under measured radiative forcing agents in the Polar Region is the absorbing aerosol - black carbon and brown carbon. In particular, vertical profile information of BC is critical in reducing uncertainty in model assessment of aerosol radiative impact at high latitudes. During the summer of 2015, a Single-Particle Soot Photometer (SP2) was deployed aboard the Department of Energy (DOE) Gultstream-1 (G-1) aircraft to measure refractory BC (rBC) concentrations as part of the DOE-sponsored ACME-V (ARM Airborne Carbon Measurements) campaign. This campaign was conducted from June through to mid-September along the North Slope of Alaska and was punctuated by vertical profiling over 5 sites (Atquasuk, Barrow, Ivotuk, Oliktok, and Toolik). In addition, measurement of CO, CO2 and CH4were also taken to provide information on the spatial and seasonal differences in GHG sources and how these sources correlate with BC. Lastly, these aerosol and gas measurements provide an important dataset to assess the representativeness of ground sites at regional scales. Comparisons between observations and a global climate model (CAM5) simulations will be agumented with a discussion on the capability of the model to capture observed monthly mean profiles of BC and stratified aerosol layers. Additionally, the ability of the SP2 to partition rBC-containing particles into nascent or aged species allows an evaluation of how well the CAM5 model captures aging of long distant transported carbonaceous aerosols. Finally model sensitivity studies will be aso be presented that investigated the relative importance of the different emission sectors to the summer Arctic

  6. Normalized vertical ice mass flux profiles from vertically pointing 8-mm-wavelength Doppler radar

    NASA Technical Reports Server (NTRS)

    Orr, Brad W.; Kropfli, Robert A.

    1993-01-01

    During the FIRE 2 (First International Satellite Cloud Climatology Project Regional Experiment) project, NOAA's Wave Propagation Laboratory (WPL) operated its 8-mm wavelength Doppler radar extensively in the vertically pointing mode. This allowed for the calculation of a number of important cirrus cloud parameters, including cloud boundary statistics, cloud particle characteristic sizes and concentrations, and ice mass content (imc). The flux of imc, or, alternatively, ice mass flux (imf), is also an important parameter of a cirrus cloud system. Ice mass flux is important in the vertical redistribution of water substance and thus, in part, determines the cloud evolution. It is important for the development of cloud parameterizations to be able to define the essential physical characteristics of large populations of clouds in the simplest possible way. One method would be to normalize profiles of observed cloud properties, such as those mentioned above, in ways similar to those used in the convective boundary layer. The height then scales from 0.0 at cloud base to 1.0 at cloud top, and the measured cloud parameter scales by its maximum value so that all normalized profiles have 1.0 as their maximum value. The goal is that there will be a 'universal' shape to profiles of the normalized data. This idea was applied to estimates of imf calculated from data obtained by the WPL cloud radar during FIRE II. Other quantities such as median particle diameter, concentration, and ice mass content can also be estimated with this radar, and we expect to also examine normalized profiles of these quantities in time for the 1993 FIRE II meeting.

  7. Aerosol vertical distribution and optical properties over China from long-term satellite and ground-based remote sensing

    NASA Astrophysics Data System (ADS)

    Tian, Pengfei; Cao, Xianjie; Zhang, Lei; Sun, Naixiu; Sun, Lu; Logan, Timothy; Shi, Jinsen; Wang, Yuan; Ji, Yuemeng; Lin, Yun; Huang, Zhongwei; Zhou, Tian; Shi, Yingying; Zhang, Renyi

    2017-02-01

    The seasonal and spatial variations of vertical distribution and optical properties of aerosols over China are studied using long-term satellite observations from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and ground-based lidar observations and Aerosol Robotic Network (AERONET) data. The CALIOP products are validated using the ground-based lidar measurements at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL). The Taklamakan Desert and Tibetan Plateau regions exhibit the highest depolarization and color ratios because of the natural dust origin, whereas the North China Plain, Sichuan Basin and Yangtze River Delta show the lowest depolarization and color ratios because of aerosols from secondary formation of the anthropogenic origin. Certain regions, such as the North China Plain in spring and the Loess Plateau in winter, show intermediate depolarization and color ratios because of mixed dust and anthropogenic aerosols. In the Pearl River Delta region, the depolarization and color ratios are similar to but higher than those of the other polluted regions because of combined anthropogenic and marine aerosols. Long-range transport of dust in the middle and upper troposphere in spring is well captured by the CALIOP observations. The seasonal variations in the aerosol vertical distributions reveal efficient transport of aerosols from the atmospheric boundary layer to the free troposphere because of summertime convective mixing. The aerosol extinction lapse rates in autumn and winter are more positive than those in spring and summer, indicating trapped aerosols within the boundary layer because of stabler meteorological conditions. More than 80 % of the column aerosols are distributed within 1.5 km above the ground in winter, when the aerosol extinction lapse rate exhibits a maximum seasonal average in all study regions except for the Tibetan Plateau. The aerosol extinction lapse rates in the polluted regions are higher

  8. Reconstruction of the vertical electron density profile based on vertical TEC using the simulated annealing algorithm

    NASA Astrophysics Data System (ADS)

    Jiang, Chunhua; Yang, Guobin; Zhu, Peng; Nishioka, Michi; Yokoyama, Tatsuhiro; Zhou, Chen; Song, Huan; Lan, Ting; Zhao, Zhengyu; Zhang, Yuannong

    2016-05-01

    This paper presents a new method to reconstruct the vertical electron density profile based on vertical Total Electron Content (TEC) using the simulated annealing algorithm. The present technique used the Quasi-parabolic segments (QPS) to model the bottomside ionosphere. The initial parameters of the ionosphere model were determined from both International Reference Ionosphere (IRI) (Bilitza et al., 2014) and vertical TEC (vTEC). Then, the simulated annealing algorithm was used to search the best-fit parameters of the ionosphere model by comparing with the GPS-TEC. The performance and robust of this technique were verified by ionosonde data. The critical frequency (foF2) and peak height (hmF2) of the F2 layer obtained from ionograms recorded at different locations and on different days were compared with those calculated by the proposed method. The analysis of results shows that the present method is inspiring for obtaining foF2 from vTEC. However, the accuracy of hmF2 needs to be improved in the future work.

  9. Vertical profile of fog microphysics : a case study

    NASA Astrophysics Data System (ADS)

    Burnet, Frédéric; Brilouet, Pierre-Etienne; Mazoyer, Marie; Bourrianne, Thierry; Etcheberry, Jean-Michel; Gaillard, Brigitte; Legain, Dominique; Tzanos, Diane; Barrié, Joel; Barrau, Sébastien; Defoy, Stephan

    2016-04-01

    The occurrence and development of fogs result from the non-linear interaction of competing radiative, thermodynamic, microphysical and dynamical processes and the forecasting of their life cycle still remains a challenging issue. Several field campaigns have been carried out at the SIRTA observatory in the Paris suburb area (France). These experiments have shown that fog events exhibit large differences of the microphysical properties and various evolutions during their life cycle. To better understand relationships between the different processes and to validate numerical simulations it is necessary however to document the vertical profile of the fog microphysics. A CDP (Cloud Droplet Spectrometer) from DMT (Droplet Measurement Technology, Boulder, CO) has been modified to allow measurements of the droplet size distribution in fog layers with a tethered balloon. This instrumental set-up has been used during a field campaign during the winter 2013-214 in the Landes area in the South West of France. To validate the vertical profiles provided by the modified CDP, a mast was equipped with microphysical instruments at 2 altitude levels with an another CDP at 24 m and a Fog Monitor FM100 at 42 m. The instrumental set-up deployed during this campaign is presented. Data collected during a fog event that occurred during the night of 5-6 March 2014 are analysed. We show that microphysical properties such as droplet number concentration, LWC and mean droplet size, exhibit different time evolution during the fog life cycle depending on the altitude level. Droplet size distribution measurements are also investigated. They reveal sharp variations along the vertical close to the top of the fog layer. In addition it is shown that the shape of the size distributions at the top follows a time evolution typical of a quasi-adiabatic droplet growth.

  10. North-south cross sections of the vertical aerosol distribution over the Atlantic Ocean from multiwavelength Raman/polarization lidar during Polarstern cruises

    PubMed Central

    Kanitz, T; Ansmann, A; Engelmann, R; Althausen, D

    2013-01-01

    Shipborne aerosol lidar observations were performed aboard the research vessel Polarstern in 2009 and 2010 during three north-south cruises from about 50°N to 50°S. The aerosol data set provides an excellent opportunity to characterize and contrast the vertical aerosol distribution over the Atlantic Ocean in the polluted northern and relatively clean southern hemisphere. Three case studies, an observed pure Saharan dust plume, a Patagonian dust plume east of South America, and a case of a mixed dust/smoke plume west of Central Africa are exemplarily shown and discussed by means of their optical properties. The meridional transatlantic cruises were used to determine the latitudinal cross section of the aerosol optical thickness (AOT). Profiles of particle backscatter and extinction coefficients are presented as mean profiles for latitudinal belts to contrast northern- and southern-hemispheric aerosol loads and optical effects. Results of lidar observations at Punta Arenas (53°S), Chile, and Stellenbosch (34°S), South Africa, are shown and confirm the lower frequency of occurrence of free-tropospheric aerosol in the southern hemisphere than in the northern hemisphere. The maximum latitudinal mean AOT of 0.27 was found in the northern tropics (0– 15°N) in the Saharan outflow region. Marine AOT is typically 0.05 ± 0.03. Particle optical properties are presented separately for the marine boundary layer and the free troposphere. Concerning the contrast between the anthropogenically influenced midlatitudinal aerosol conditions in the 30– 60°N belt and the respective belt in the southern hemisphere over the remote Atlantic, it is found that the AOT and extinction coefficients for the vertical column from 0–5km (total aerosol column) and 1–5km height (lofted aerosol above the marine boundary layer) are a factor of 1.6 and 2 higher at northern midlatitudes than at respective southern midlatitudes, and a factor of 2.5 higher than at the clean marine southern

  11. The vertical distribution of BrO and aerosols in the Arctic: Measurements by active and passive differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Frieß, U.; Sihler, H.; Sander, R.; PöHler, D.; Yilmaz, S.; Platt, U.

    2011-07-01

    We present results from multiaxis differential optical absorption spectroscopy (MAX-DOAS) and long-path DOAS (LP-DOAS) measurements performed at the North Slope of Alaska from February to April 2009 as part of the Ocean-Atmosphere-Sea Ice-Snowpack Barrow 2009 campaign. For the first time, vertical profiles of aerosol extinction and BrO in the boundary layer were retrieved simultaneously from MAX-DOAS measurements using the method of optimal estimation. Even at very low visibility, retrieved extinction profiles and aerosol optical thickness are in good agreement with colocated ceilometer and Sun photometer measurements, respectively. BrO surface concentrations measured by MAX-DOAS and LP-DOAS are in very good agreement, and it has been found that useful information on the BrO vertical distribution can be retrieved from MAX-DOAS even in cases when blowing snow strongly reduces visibility. The retrieved BrO and extinction vertical profiles allow for a thorough characterization of the vertical structure of the boundary layer during numerous ozone depletion events observed during Barrow 2009. High BrO concentrations are usually present during the onset of ozone depletion events, and BrO disappears as ozone concentrations approach zero. The finding that elevated BrO concentrations occur mainly in the presence of high extinction near the surface strongly suggests that release of reactive bromine from airborne aerosols and/or ice particles at high wind speed plays an important role. Back trajectory calculations indicate that the particles were transported from the frozen ocean to the measurement site and that the release of reactive bromine from sea ice and/or frost flowers occurs when low temperatures (<250 K) prevail in the regions where reactive bromine is emitted.

  12. LIDAR Observations of the Vertical Ozone and Aerosol Distribution over Mexico City during the MCMA-2003 Field Campaign

    NASA Astrophysics Data System (ADS)

    Simeonov, V.; Ristori, P.; Taslakov, M.; Dinoev, T.; van den Bergh, H.; Frey, S.; Molina, L. T.; Molina, M. J.

    2004-12-01

    An international field measurement campaign was held in April - May 2003 in the Mexico City Metropolitan Area (MCMA) as part of an effort to understand the complex urban air pollution problems in large cities. Gas phase and aerosol constituents were studied intensively during the campaign. LIDAR played an important role for measuring boundary layer dynamics and photochemical processes by monitoring the vertical distribution of aerosols and ozone. Two elastic DIAL and one Raman DIAL for ozone measurements were operated quasi-simultaneously during the campaign at the CENICA super site. The lidar of the Swiss Federal Institute of Technology, Lausanne (EPFL), Switzerland is an elastic three-wavelength UV DIAL combined with an aerosol lidar at 532 nm with an operational range of 200-6000 m for ozone measurements and 200-10000 m for aerosol measurements. The other elastic system is a commercial, stand alone two-wavelength DIAL produced and operated by ELIGHT Laser Systems GmbH. It performed ozone measurements from 400 to 2000 m. A combined Raman DIAL and aerosol Raman system was on loan from Freie Universität Berlin. This instrument was operated by the MIT team and provided ozone concentration from 350 to 2600 m and multicolor aerosol backscatter, Raman and depolarization. The campaign was designed to cover the height of the annual photochemical season. Rain episodes during the afternoons and the evenings at the beginning of the campaign caused discontinuity in the observation. Improved meteorological conditions from April 25 to May 3 made continuous measurements of all participating Lidars possible. A cloud-topped boundary layer (BL) was the frequently observed in the afternoon during this period. The top of the BL estimated from the aerosol measurements showed steady day-to-day increase, reaching altitudes of up to 4 km, comparable to the altitudes of the surrounding mountains. An obvious detachment of the top of the BL was also observed by the EPFL Lidar during the

  13. Retrieval of vertical profiles of multiple trace gases from MAX-DOAS observations during the MADCAT Campaign in Mainz, Germany

    NASA Astrophysics Data System (ADS)

    Wang, Yang; Xie, Pinhua; Wagner, Thomas; Li, Ang; Luo, Yuhan; Remmers, Julia; Horbanski, Martin; Friess, Udo

    2014-05-01

    In order to promote the development of passive DOAS technique and solve some critical problems including e.g. accurate retrievals of trace gas slant column densities (SCD), profile retrievals of trace gases and aerosol, and the effects of cloud, the Multi Axis DOAS-Comparison campaign for Aerosols and Trace gases (MAD-CAT) was held at the Max-Planck institute for Chemistry in Mainz, Germany from June to August 2013. Within this campaign, spectra of scattered sun light were taken by our two-dimensional scanning MAX-DOAS (2D-MAX-DOAS) instrument and a Mini-MAX-DOAS instrument from the Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences. In this presentation, firstly we show the retrieved differential SCDs of O4, NO2, HCHO, HONO and CHOCHO based on the observations of the 2D-MAX-DOAS. Based on these dSCDs we acquired the vertical profiles of these trace gases and aerosol extinction using optimal estimation method. We compare the aerosol optical depth (AOD) from MAX-DOAS with simultaneous observations from an AERONET instrument as well as the near surface volume mixing ratio (VMR) of NO2 from MAX-DOAS with those from a CE-DOAS instrument from the IUP Heidelberg group and found in general good agreement. In addition we apply a cloud classification scheme based on our MAX-DOAS observations to identify different kinds of weather during the MAD-CAT campaign.

  14. Mechanistic simulation of the vertical soil organic matter profile

    NASA Astrophysics Data System (ADS)

    Braakhekke, M.; Beer, C.; Reichstein, M.; Hoosbeek, M.; Kruijt, B.; Kabat, P.

    2013-12-01

    Soil organic matter (SOM) constitutes a large global pool of carbon that may play a considerable role for future climate. The vertical distribution of SOM in the profile may be important due to depth-dependence of physical, chemical, and biological conditions, and links to physical processes such as heat and moisture transport. The aim of this thesis is to develop a dynamic and mechanistic representation of the vertical SOM profile that can be applied for large scale simulations as a part of global ecosystem and earth system models. A model structure called SOMPROF was developed that dynamically simulates the SOM profile based on above and below ground litter input, decomposition, bioturbation, and liquid phase transport. Furthermore, three organic surface horizons are explicitly represented. Since the organic matter transport processes have been poorly quantified in the past and are difficult to observe directly, the model was calibrated with a Bayesian approach for two contrasting temperate forest sites in Europe. Different types of data were included in the parameter estimation, including: organic carbon stocks and concentrations, respiration rates, and excess lead-210 activity. The calibrations yielded good fits to the observations, and showed that the two sites differ considerably with respect to the relevance of the different processes. These differences agree well with expectations based on local conditions. However, the results also demonstrate the difficulties arising from convolution of the processes. Several parameters are poorly constrained and for one of the sites, several distinct regions in parameter space exist that yield acceptable fit. In a subsequent study it was found that radiocarbon observations can offer much additional constraint on several parameters, most importantly on the turnover rate of the slowest SOM fraction. Additionally, for one site, a prognostic simulation until 2100 was performed using the resulting a posteriori parameter

  15. Connection between Mature Stages of Deep Convection and the Vertical Transport of Aerosols in the Upper Troposphere

    NASA Astrophysics Data System (ADS)

    Chakraborty, S.; Fu, R.; Massie, S. T.; Pan, L.

    2011-12-01

    Convective transport of aerosol has implications to aerosol-cloud interactions and is an important problem for climate studies. We use along-track Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (Calipso) vertical feature mask data, CloudSat data, and International Satellite Cloud Climatology Project (ISCCP) deep convection tracking data to study the impact of deep convection on the transport of aerosols to the upper troposphere (UT) over the South Asian region (0-40N, 70-100E). To minimize misclassification among aerosols and the clouds at UT, we have only used data having large magnitude of cloud aerosol discrimination (CAD) scores for the period of June 2006 to June 2008 when CloudSat and Calipso overlap with the ISCCP deep convection tracking data. Preliminary results suggest that active clouds most likely transport aerosols to high altitudes, whereas decaying clouds are least likely to transport aerosols to the UT. Mature clouds act in-between the active and decaying clouds. Active clouds that transport aerosols are different than decaying clouds in terms of higher cloud water path, cloud water content at 10 km altitude, number of convective clusters, and convective fraction. The NASA Goddard Global Modeling and Assimilation Office wind data, projected onto the CloudSat tracks, suggests a strong updraft associated with active clouds in favor of aerosol transportation, and a low level or mid-level subsidence associated with decaying clouds.

  16. Vertical Distribution and Columnar Optical Properties of Springtime Biomass-Burning Aerosols over Northern Indochina during the 7-SEAS/BASELInE field campaign

    NASA Astrophysics Data System (ADS)

    Lin, N. H.; Wang, S. H.; Welton, E. J.; Holben, B. N.; Tsay, S. C.; Giles, D. M.; Stewart, S. A.; Janjai, S.; Anh, N. X.; Hsiao, T. C.; Chen, W. N.; Lin, T. H.; Buntoung, S.; Chantara, S.; Wiriya, W.

    2015-12-01

    In this study, the aerosol optical properties and vertical distributions in major biomass-burning emission area of northern Indochina were investigated using ground-based remote sensing (i.e., four Sun-sky radiometers and one lidar) during the Seven South East Asian Studies/Biomass-burning Aerosols & Stratocumulus Environment: Lifecycles & Interactions Experiment conducted during spring 2014. Despite the high spatial variability of the aerosol optical depth (AOD; which at 500 nm ranged from 0.75 to 1.37 depending on the site), the temporal variation of the daily AOD demonstrated a consistent pattern among the observed sites, suggesting the presence of widespread smoke haze over the region. Smoke particles were characterized as small (Ångström exponent at 440-870 nm of 1.72 and fine mode fraction of 0.96), strongly absorbing (single-scattering albedo at 440 nm of 0.88), mixture of black and brown carbon particles (absorption Ångström exponent at 440-870 nm of 1.5) suspended within the planetary boundary layer (PBL). Smoke plumes driven by the PBL dynamics in the mountainous region reached as high as 5 km above sea level; these plumes subsequently spread out by westerly winds over northern Vietnam, southern China, and the neighboring South China Sea. Moreover, the analysis of diurnal variability of aerosol loading and optical properties as well as vertical profile in relation to PBL development, fire intensity, and aerosol mixing showed that various sites exhibited different variability based on meteorological conditions, fuel type, site elevation, and proximity to biomass-burning sources. These local factors influence the aerosol characteristics in the region and distinguish northern Indochina smoke from other biomass-burning regions in the world.

  17. Remote Sensing the Vertical Profile of Cloud Droplet Effective Radius, Thermodynamic Phase, and Temperature

    NASA Technical Reports Server (NTRS)

    Martins, J. V.; Marshak, A.; Remer, L. A.; Rosenfeld, D.; Kaufman, Y. J.; Fernandez-Borda, R.; Koren, I.; Correia, A. L.; Zubko, V.; Artaxo, P.

    2011-01-01

    Cloud-aerosol interaction is a key issue in the climate system, affecting the water cycle, the weather, and the total energy balance including the spatial and temporal distribution of latent heat release. Information on the vertical distribution of cloud droplet microphysics and thermodynamic phase as a function of temperature or height, can be correlated with details of the aerosol field to provide insight on how these particles are affecting cloud properties and their consequences to cloud lifetime, precipitation, water cycle, and general energy balance. Unfortunately, today's experimental methods still lack the observational tools that can characterize the true evolution of the cloud microphysical, spatial and temporal structure in the cloud droplet scale, and then link these characteristics to environmental factors and properties of the cloud condensation nuclei. Here we propose and demonstrate a new experimental approach (the cloud scanner instrument) that provides the microphysical information missed in current experiments and remote sensing options. Cloud scanner measurements can be performed from aircraft, ground, or satellite by scanning the side of the clouds from the base to the top, providing us with the unique opportunity of obtaining snapshots of the cloud droplet microphysical and thermodynamic states as a function of height and brightness temperature in clouds at several development stages. The brightness temperature profile of the cloud side can be directly associated with the thermodynamic phase of the droplets to provide information on the glaciation temperature as a function of different ambient conditions, aerosol concentration, and type. An aircraft prototype of the cloud scanner was built and flew in a field campaign in Brazil.

  18. Titan's Aerosol and Stratospheric Ice Opacities Between 18 and 500 Micrometers: Vertical and Spectral Characteristics from Cassini CIRS

    NASA Technical Reports Server (NTRS)

    Anderson, Carrie M.; Samuelson, Robert E.

    2011-01-01

    Vertical distributions and spectral characteristics of Titan's photochemical aerosol and stratospheric ices are determined between 20 and 560 per centimeter (500-18 micrometers) from the Cassini Composite Infrared Spectrometer (CIRS). Results are obtained for latitudes of 15 N, 15 S, and 58 S, where accurate temperature profiles can be independently determined. In addition, estimates of aerosol and ice abundances at 62 N relative to those at 15 S are derived. Aerosol abundances are comparable at the two latitudes, but stratospheric ices are approximately 3 times more abundant at 62 N than at 15 S. Generally, nitrile ice clouds (probably HCN and HC3N), as inferred from a composite emission feature at approximately 160 per centimeter, appear to be located over a narrow altitude range in the stratosphere centered at approximately 90 km. Although most abundant at high northern latitudes, these nitrile ice clouds extend down through low latitudes and into mid southern latitudes, at least as far as 58 S. There is some evidence of a second ice cloud layer at approximately 60 km altitude at 58 S associated with an emission feature at approximately 80 per centimeter. We speculate that the identify of this cloud may be due to C2H6 ice, which in the vapor phase is the most abundant hydrocarbon (next to CH4) in the stratosphere of Titan. Unlike the highly restricted range of altitudes (50-100 km) associated with organic condensate clouds, Titan's photochemical aerosol appears to be well-mixed from the surface to the top of the stratosphere near an altitude of 300 km, and the spectral shape does not appear to change between 15 N and 58 S latitude. The ratio of aerosol-to-gas scale heights range from 1.3-2.4 at about 160 km to 1.1-1.4 at 300 km, although there is considerable variability with latitude, The aerosol exhibits a very broad emission feature peaking at approximately 140 per centimeter. Due to its extreme breadth and low wavenumber, we speculate that this feature may

  19. Global View of Aerosol Vertical Distributions from CALIPSO Lidar Measurements and GOCART Simulations: Regional and Seasonal Variations

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin; Chin, Mian; Winker, David M.; Omar, Ali H.; Liu, Zhaoyan; Kittaka, Chieko; Diehl, Thomas

    2010-01-01

    This study examines seasonal variations of the vertical distribution of aerosols through a statistical analysis of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar observations from June 2006 to November 2007. A data-screening scheme is developed to attain good quality data in cloud-free conditions, and the polarization measurement is used to separate dust from non-dust aerosol. The CALIPSO aerosol observations are compared with aerosol simulations from the Goddard Chemistry Aerosol Radiation Transport (GOCART) model and aerosol optical depth (AOD) measurements from the MODerate resolution Imaging Spectroradiometer (MODIS). The CALIPSO observations of geographical patterns and seasonal variations of AOD are generally consistent with GOCART simulations and MODIS retrievals especially near source regions, while the magnitude of AOD shows large discrepancies in most regions. Both the CALIPSO observation and GOCART model show that the aerosol extinction scale heights in major dust and smoke source regions are generally higher than that in industrial pollution source regions. The CALIPSO aerosol lidar ratio also generally agrees with GOCART model within 30% on regional scales. Major differences between satellite observations and GOCART model are identified, including (1) an underestimate of aerosol extinction by GOCART over the Indian sub-continent, (2) much larger aerosol extinction calculated by GOCART than observed by CALIPSO in dust source regions, (3) much weaker in magnitude and more concentrated aerosol in the lower atmosphere in CALIPSO observation than GOCART model over transported areas in midlatitudes, and (4) consistently lower aerosol scale height by CALIPSO observation than GOCART model. Possible factors contributing to these differences are discussed.

  20. Retrieving the aerosol lidar ratio profile by combining ground- and space-based elastic lidars.

    PubMed

    Feiyue, Mao; Wei, Gong; Yingying, Ma

    2012-02-15

    The aerosol lidar ratio is a key parameter for the retrieval of aerosol optical properties from elastic lidar, which changes largely for aerosols with different chemical and physical properties. We proposed a method for retrieving the aerosol lidar ratio profile by combining simultaneous ground- and space-based elastic lidars. The method was tested by a simulated case and a real case at 532 nm wavelength. The results demonstrated that our method is robust and can obtain accurate lidar ratio and extinction coefficient profiles. Our method can be useful for determining the local and global lidar ratio and validating space-based lidar datasets.

  1. Analysis and characterization of the vertical wind profile in UAE

    NASA Astrophysics Data System (ADS)

    Lee, W.; Ghedira, H.; Ouarda, T.; Gherboudj, I.

    2011-12-01

    In this study, temporal and spatial analysis of the vertical wind profiles in the UAE has been performed to estimate wind resource potential. Due to the very limited number of wind masts (only two wind masts in the UAE, operational for less than three years), the wind potential analysis will be mainly derived from numerical-based models. Additional wind data will be derived from the UAE met stations network (at 10 m elevation) managed by the UAE National Center of Meteorology and Seismology. However, since wind turbines are generally installed at elevations higher than 80 m, it is vital to extrapolate wind speed correctly from low heights to wind turbine hub heights to predict potential wind energy properly. To do so, firstly two boundary layer based models, power law and logarithmic law, were tested to find the best fitting model. Power law is expressed as v/v0 =(H/H0)^α and logarithmic law is represented as v/v0 =[ln(H/Z0))/(ln(H0/Z0)], where V is the wind speed [m/s] at height H [m] and V0 is the known wind speed at a reference height H0. The exponent (α) coefficient is an empirically derived value depending on the atmospheric stability and z0 is the roughness coefficient length [m] that depends on topography, land roughness and spacing. After testing the two models, spatial and temporal analysis for wind profile was performed. Many studies about wind in different regions have shown that wind profile parameters have hourly, monthly and seasonal variations. Therefore, it can be examined whether UAE wind characteristics follow general wind characteristics observed in other regions or have specific wind features due to its regional condition. About 3 years data from August 2008 to February 2011 with 10-minutes resolution were used to derive monthly variation. The preliminary results(Fig.1) show that during that period, wind profile parameters like alpha from power law and roughness length from logarithmic law have monthly variation. Both alpha and roughness have

  2. Multi-component vertical profile retrievals for ground-based MAX-DOAS

    NASA Astrophysics Data System (ADS)

    Irie, Hitoshi; Kanaya, Yugo; Takashima, Hisahiro; van Roozendael, Michel; Wittrock, Folkard; Piters, Ankie

    2010-05-01

    We attempt to retrieve lower-tropospheric vertical profile information for 8 components from ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements. The components retrieved include aerosol extinction coefficients (AEC) at two wavelengths 357 and 476 nm, NO2, HCHO, CHOCHO, H2O, SO2, and O3 volume mixing ratios (VMRs). This method was applied to MAX-DOAS observations performed at Cabauw, the Netherlands (52.0°N, 4.9°E) in June-July 2009 during the Cabauw Intercomparison campaign of Nitrogen Dioxide measuring Instruments (CINDI) campaign. For the lowest layer of retrieved profiles at 0-1 km, two channels of AEC values reveal consistent variations. NO2 showed typical diurnal variations with maximum in early morning and minimum in the afternoon. Positive correlations between HCHO and CHOCHO were often seen. H2O VMR agreed well with that derived from NCEP surface data, and was used to judge cloudy cases after conversion to relative humidity. All these results support the capability of MAX-DOAS observations applicable to various air quality studies. Similar multi-component retrievals applied to observations in Japan are also presented in this talk.

  3. Comparison of aerosol extinction profiles from lidar and SAGE II data at a tropical station

    NASA Technical Reports Server (NTRS)

    Parameswaran, K.; Rose, K. O.; Murthy, B. V. K.; Osborn, M. T.; Mcmaster, L. R.

    1991-01-01

    Aerosol extinction profiles obtained from lidar data at Trivandrum (8.6 deg N, 77 deg E) are compared with corresponding Stratospheric Aerosol and Gas Experiment II extinction profiles. The agreement between the two is found to be satisfactory. The extinction profiles obtained by both the experiments showed a prominent peak at 23-24 km altitude in the stratosphere. The study revealed large variability in upper tropospheric extinction with location (latitude).

  4. Vertical Profiles of Ammonia in the Colorado Front Range: Impacts of Source Region and Meteorology

    NASA Astrophysics Data System (ADS)

    Tevlin, A.; Kaushik, A.; Noone, D. C.; Ortega, J. V.; Smith, J. N.; Brophy, P.; Kirkland, J.; Link, M. F.; Farmer, D. K.; Wolfe, D. E.; Dube, W. P.; McDuffie, E. E.; Brown, S. S.; Zaragoza, J.; Fischer, E. V.; Murphy, J. G.

    2014-12-01

    Atmospheric ammonia plays an important role in aerosol particle formation and growth, as well as in nitrogen deposition to sensitive ecosystems. However, significant uncertainties are associated with the distribution and strength of emission sources, and many of the processes that control its atmospheric fate are not fully understood. The high density of agricultural and urban sources located in close proximity to more pristine mountainous areas to the west make the Colorado Front Range a unique area for studying atmospheric ammonia. The meteorology of the region, where heavy monsoon rains can be followed by rapid evaporation, can also impact surface-atmosphere partitioning of ammonia. As part of the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ), vertical profiles of ammonia were measured throughout the boundary layer aboard a moveable platform on the 300 m Boulder Atmospheric Observatory (BAO) tower. Changes in ammonia concentration and its vertical structure were driven not only by changes in wind direction and estimated source region, but also by fluctuations in surface and atmosphere water content. For example, large increases in atmospheric ammonia mixing ratios were observed following rain events. This may be explained by surface-atmosphere exchange of wet-deposited ammonia associated with rapid evaporation following the event, and likely impacts particle formation. This may also play a role in transport from ammonia-rich agricultural areas towards the mountainous regions to the west during periods of upslope flow. The vertical ammonia concentration gradients observed throughout the structured early morning boundary layer also provide insight into the possible causes of early morning spikes in ammonia - a phenomenon that has been well-documented in many other locations. A box model was used to assess the relative importance of surface emissions due to the evaporation of morning dew versus entrainment of ammonia-rich air from above the

  5. Relation of Cloud Occurrence Frequency, Overlap, and Effective Thickness Derived from CALIPSO and CloudSat Merged Cloud Vertical Profiles

    NASA Technical Reports Server (NTRS)

    Kato, Seiji; Sun-Mack, Sunny; Miller, Walter F.; Rose, Fred G.; Chen, Yan; Minnis, Patrick; Wielicki, Bruce A.

    2009-01-01

    A cloud frequency of occurrence matrix is generated using merged cloud vertical profile derived from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Cloud Profiling Radar (CPR). The matrix contains vertical profiles of cloud occurrence frequency as a function of the uppermost cloud top. It is shown that the cloud fraction and uppermost cloud top vertical pro les can be related by a set of equations when the correlation distance of cloud occurrence, which is interpreted as an effective cloud thickness, is introduced. The underlying assumption in establishing the above relation is that cloud overlap approaches the random overlap with increasing distance separating cloud layers and that the probability of deviating from the random overlap decreases exponentially with distance. One month of CALIPSO and CloudSat data support these assumptions. However, the correlation distance sometimes becomes large, which might be an indication of precipitation. The cloud correlation distance is equivalent to the de-correlation distance introduced by Hogan and Illingworth [2000] when cloud fractions of both layers in a two-cloud layer system are the same.

  6. MEASURING VERTICAL PROFILES OF HYDRAULIC CONDUCTIVITY WITH IN SITU DIRECT-PUSH METHODS

    EPA Science Inventory

    U.S. EPA (Environmental Protection Agency) staff developed a field procedure to measure hydraulic conductivity using a direct-push system to obtain vertical profiles of hydraulic conductivity. Vertical profiles were obtained using an in situ field device-composed of a
    Geopr...

  7. Seasonal variations in Titan's stratosphere observed with Cassini/CIRS: temperature, trace molecular gas and aerosol mixing ratio profiles

    NASA Astrophysics Data System (ADS)

    Vinatier, S.; Bézard, B.; Lebonnois, S.; Teanby, N. A.; Rannou, P.; Anderson, C. M.; Achterberg, R. K.

    2013-12-01

    Titan's northern spring equinox occurred in August 2009. General Circulation Models predict strong modifications of the global circulation in this period, with formation of two circulation cells instead of the pole-to-pole cell that occurred during northern winter. This winter single cell, which had its descending branch at the north pole, was at the origin of the enrichment of molecular abundances and high stratopause temperatures observed by Cassini/CIRS at high northern latitudes. The predicted dynamical seasonal variations after the equinox have strong impact on the spatial distributions of trace gas, temperature and aerosol abundances. We will present here an analysis of CIRS limb-geometry datasets acquired between 2009 and 2013 that we used to monitor the seasonal evolution of the vertical profiles of temperature, molecular (C2H2, C2H6, HCN, ...) and aerosol abundances.

  8. LIDAR vertical profiles over the Oil Sands Region: an important tool in understanding atmospheric particulate matter transport, mixing and transformation

    NASA Astrophysics Data System (ADS)

    Strawbridge, K. B.

    2013-12-01

    LIDAR technology is an excellent tool to probe the complex vertical structure of the atmosphere at high spatial and temporal resolution. This provides the critical vertical context for the interpretation of ground-based chemistry measurements, airborne measurements and model verification and validation. In recent years, Environment Canada has designed an autonomous aerosol LIDAR system that can be deployed to remote areas such as the oil sands. Currently two autonomous LIDAR systems are making measurements in the oil sands region, one since December, 2012 and the other since July, 2013. The LIDAR transmitter emits two wavelengths (1064nm and 532nm) and the detector assembly collects four channels (1064nm backscatter, 532nm backscatter and 532nm depolarization, 607 nm nitrogen channel). Aerosol profiles from near ground to 20 km are collected every 10-60 s providing sufficient resolution to probe atmospheric dynamics, mixing and transport. The depolarization channel provides key information in identifying and discriminating the various aerosol layers aloft such as dust, forest fire plumes, industrial plume sources or ice crystals. The vertical resolution of the LIDAR can determine whether industrial plumes remain aloft or mix down to the surface and also provide estimates as to the concentration of the particulate at various altitudes. It operates 24 hours a day, seven days a week except during precipitation events. The system is operated remotely and the data are updated every hour to a website to allow near real-time capability. An intensive measurement campaign will be carried out in August and September of 2013 and will provide coincident airborne and ground-based measurements for the two LIDAR systems. The first results from this field study will be presented as well as some statistics on the frequency and evolution of plume events that were detected by the LIDARs.

  9. Vertical particle concentration profiles around urban office buildings

    NASA Astrophysics Data System (ADS)

    Quang, T. N.; He, C.; Morawska, L.; Knibbs, L. D.; Falk, M.

    2012-06-01

    Despite its role in determining both indoor and outdoor human exposure to anthropogenic particles, there is limited information describing vertical profiles of particle concentrations in urban environments, especially for ultrafine particles. Furthermore, the results of the few studies performed have been inconsistent. As such, this study aimed to assess the influence of vehicle emissions and nucleation formation on particle characteristics (particle number size distribution - PNSD and PM2.5 concentration) at different heights around three urban office buildings located next to busy roads in Brisbane, Australia, and place these results in the broader context of the existing literature. Two sets of instruments were used to simultaneously measure PNSD, particle number (PN) and PM2.5 concentrations, respectively, for up to three weeks at each building. The results showed that both PNSD and PM2.5 concentration around building envelopes were influenced by vehicle emissions and new particle formation, and that they exhibited variability across the three different office buildings. During nucleation events, PN concentration in size range of <30 nm and total PN concentration increased (7-65% and 5-46%, respectively), while PM2.5 concentration decreased (36-52%) with height. This study has shown an under acknowledged role for nucleation in producing particles that can affect large numbers of people, due to the high density and occupancy of urban office buildings and the fact that the vast majority of people's time is spent indoors. These findings highlight important new information related to the previously overlooked role of particle formation in the urban atmosphere and its potential effects on selection of air intake locations and appropriate filter types when designing or upgrading mechanical ventilation systems in urban office buildings. The results also serve to better define particle behaviour and variability around building envelopes, which has implications for

  10. The Cloud-Aerosol Transport System (CATS): a New Lidar for Aerosol and Cloud Profiling from the International Space Station

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; McGill, Matthew J.; Yorks, John E.; Hlavka, Dennis L.; Hart, William D.; Palm, Stephen P.; Colarco, Peter R.

    2011-01-01

    Spaceborne lidar profiling of aerosol and cloud layers has been successfully implemented during a number of prior missions, including LITE, ICESat, and CALIPSO. Each successive mission has added increased capability and further expanded the role of these unique measurements in wide variety of applications ranging from climate, to air quality, to special event monitoring (ie, volcanic plumes). Many researchers have come to rely on the availability of profile data from CALIPSO, especially data coincident with measurements from other A-Train sensors. The CALIOP lidar on CALIPSO continues to operate well as it enters its fifth year of operations. However, active instruments have more limited lifetimes than their passive counterparts, and we are faced with a potential gap in lidar profiling from space if the CALIOP lidar fails before a new mission is operational. The ATLID lidar on EarthCARE is not expected to launch until 2015 or later, and the lidar component of NASA's proposed Aerosols, Clouds, and Ecosystems (ACE) mission would not be until after 2020. Here we present a new aerosol and cloud lidar that was recently selected to provide profiling data from the International Space Station (ISS) starting in 2013. The Cloud-Aerosol Transport System (CATS) is a three wavelength (1064, 532, 355 nm) elastic backscatter lidar with HSRL capability at 532 nm. Depolarization measurements will be made at all wavelengths. The primary objective of CATS is to continue the CALIPSO aerosol and cloud profile data record, ideally with overlap between both missions and EarthCARE. In addition, the near real time data capability of the ISS will enable CATS to support operational applications such as air quality and special event monitoring. The HSRL channel will provide a demonstration of technology and a data testbed for direct extinction retrievals in support of ACE mission development. An overview of the instrument and mission will be provided, along with a summary of the science

  11. Development of a Climatology of Vertically Complete Wind Profiles from Doppler Radar Wind Profiler Systems

    NASA Technical Reports Server (NTRS)

    Barbre, Robert E., Jr.

    2015-01-01

    This paper describes in detail the QC and splicing methodology for KSC's 50- and 915-MHz DRWP measurements that generates an extensive archive of vertically complete profiles from 0.20-18.45 km. The concurrent POR from each archive extends from April 2000 to December 2009. MSFC NE applies separate but similar QC processes to each of the 50- and 915-MHz DRWP archives. DRWP literature and data examination provide the basis for developing and applying the automated and manual QC processes on both archives. Depending on the month, the QC'ed 50- and 915-MHz DRWP archives retain 52-65% and 16-30% of the possible data, respectively. The 50- and 915-MHz DRWP QC archives retain 84-91% and 85-95%, respectively, of all the available data provided that data exist in the non- QC'ed archives. Next, MSFC NE applies an algorithm to splice concurrent measurements from both DRWP sources. Last, MSFC NE generates a composite profile from the (up to) five available spliced profiles to effectively characterize boundary layer winds and to utilize all possible 915-MHz DRWP measurements at each timestamp. During a given month, roughly 23,000-32,000 complete profiles exist from 0.25-18.45 km from the composite profiles' archive, and approximately 5,000- 27,000 complete profiles exist from an archive utilizing an individual 915-MHz DRWP. One can extract a variety of profile combinations (pairs, triplets, etc.) from this sample for a given application. The sample of vertically complete DRWP wind measurements not only gives launch vehicle customers greater confidence in loads and trajectory assessments versus using balloon output, but also provides flexibility to simulate different DOL situations across applicable altitudes. In addition to increasing sample size and providing more flexibility for DOL simulations in the vehicle design phase, the spliced DRWP database provides any upcoming launch vehicle program with the capability to utilize DRWP profiles on DOL to compute vehicle steering

  12. Amazon boundary layer aerosol concentration sustained by vertical transport during rainfall

    SciTech Connect

    Wang, Jian; Krejci, Radovan; Giangrande, Scott; Kuang, Chongai; Barbosa, Henrique M. J.; Brito, Joel; Carbone, Samara; Chi, Xuguang; Comstock, Jennifer; Ditas, Florian; Lavric, Jost; Manninen, Hanna E.; Mei, Fan; Moran-Zuloaga, Daniel; Pöhlker, Christopher; Pöhlker, Mira L.; Saturno, Jorge; Schmid, Beat; Souza, Rodrigo A. F.; Springston, Stephen R.; Tomlinson, Jason M.; Toto, Tami; Walter, David; Wimmer, Daniela; Smith, James N.; Kulmala, Markku; Machado, Luiz A. T.; Artaxo, Paulo; Andreae, Meinrat O.; Petäjä, Tuukka; Martin, Scot T.

    2016-10-24

    A necessary prerequisite of cloud formation, aerosol particles represent one of the largest uncertainties in computer simulations of climate change1,2, in part because of a poor understanding of processes under natural conditions3,4. The Amazon rainforest is one of the few continental regions where aerosol particles and their precursors can be studied under near-natural conditions5-7. Cloud condensation nuclei (CCN) in clean Amazonia are mostly produced by the growth of smaller particles in the boundary layer8-10, whereas these smaller particles themselves 31 appear to be produced elsewhere5,11. Key questions are in what part of the atmosphere they might 32 be produced and what could be the transport processes that deliver them to the boundary layer, where they grow into CCN. Here, using recent aircraft measurements above central Amazonia, we show high concentrations of small particles in the lower free troposphere. The particle size spectrum shifts towards larger sizes with decreasing altitude, implying particle growth as air descends from the free troposphere towards Earth's surface. Complementary measurements at ground sites show that free tropospheric air having high concentrations of small particles (diameters of less than 50 nm) is transported into the boundary layer during precipitation events, both by strong convective downdrafts and by weaker downward motions in the trailing stratiform region. This vertical transport helps maintain the population of small particles and ultimately CCN in the boundary layer, thereby playing an important role in controlling the climate state under natural conditions. In contrast, this mechanism becomes masked under polluted conditions, which sometimes prevail at times in Amazonia as well as over other tropical continental regions5,12.

  13. Reconstruction of Vertical Profile of Permittivity of Layered Media which is Probed Using Vertical Differential Antenna

    NASA Astrophysics Data System (ADS)

    Pochanin, Gennadiy P.; Poyedinchuk, Anatoliy Y.; Varianytsia-Roshchupkina, Liudmyla A.; Pochanina, Iryna Ye.

    2016-04-01

    Results of this research are intended to use at GPR investigations of layered media (for example, at roads' inspection) for the processing of collected data and reconstruction of dependence of permittivity on the depth. Recently, an antenna system with a vertical differential configuration of receiving module (Patent UA81652) for GPR was suggested and developed The main advantage of the differential antennas in comparison with bistatic antennas is a high electromagnetic decoupling between the transmitting and receiving modules. The new vertical differential configuration has an additional advantage because it allows collecting GPR data reflected by layered media without any losses of information about these layers [1] and, potentially, it is a more accurate instrument for the layers thickness measurements [2]. The developed antenna system is tested in practice with the GPR at asphalt thickness measurements [3] and shown an accuracy which is better than 0.5 cm. Since this antenna system is good for sounding from above the surface (air coupled technique), the mobile laboratory was equipped with the developed GPR [3]. In order to process big set of GPR data that collected during probing at long routes of the roads, for the data processing it was tested new algorithm of the inverse problem solution. It uses a fast algorithm for calculation of electromagnetic wave diffraction by non-uniform anisotropic layers [4]. The algorithm is based on constructing a special case solution to the Riccati equation for the Cauchy problem and enables a qualitative description of the wave diffraction by the electromagnetic structure of the type within a unitary framework. At this stage as initial data we used synthetic GPR data that were obtained as results of the FDTD simulation of the problem of UWB electromagnetic impulse diffraction on layered media. Differential and bistatic antenna configurations were tested at several different profiles of permittivity. Meanings of permittivity of

  14. GROUND WATER SAMPLING FOR VERTICAL PROFILING OF CONTAMINANTS

    EPA Science Inventory

    Accurate delineation of plume boundaries and vertical contaminant distribution are necessary in order to adequately characterize waste sites and determine remedial strategies to be employed. However, it is important to consider the sampling objectives, sampling methods, and sampl...

  15. Vertical profiles of black carbon measured by a micro-aethalometer in summer in the North China Plain

    NASA Astrophysics Data System (ADS)

    Ran, Liang; Deng, Zhaoze; Xu, Xiaobin; Yan, Peng; Lin, Weili; Wang, Ying; Tian, Ping; Wang, Pucai; Pan, Weilin; Lu, Daren

    2016-08-01

    Black carbon (BC) is a dominant absorber in the visible spectrum and a potent factor in climatic effects. Vertical profiles of BC were measured using a micro-aethalometer attached to a tethered balloon during the Vertical Observations of trace Gases and Aerosols (VOGA) field campaign, in summer 2014 at a semirural site in the North China Plain (NCP). The diurnal cycle of BC vertical distributions following the evolution of the mixing layer (ML) was investigated for the first time in the NCP region. Statistical parameters including identified mixing height (Hm) and average BC mass concentrations within the ML (Cm) and in the free troposphere (Cf) were obtained for a selected dataset of 67 vertical profiles. Hm was usually lower than 0.2 km in the early morning and rapidly rose thereafter due to strengthened turbulence. The maximum height of the ML was reached in the late afternoon. The top of a full developed ML exceeded 1 km on sunny days in summer, while it stayed much lower on cloudy days. The sunset triggered the collapse of the ML, and a stable nocturnal boundary layer (NBL) gradually formed. Accordingly, the highest level Cm was found in the early morning and the lowest was found in the afternoon. In the daytime, BC was almost uniformly distributed within the ML and significantly decreased above the ML. During the field campaign, Cm averaged about 5.16 ± 2.49 µg m-3, with a range of 1.12 to 14.49 µg m-3, comparable with observational results in many polluted urban areas such as Milan in Italy and Shanghai in China. As evening approached, BC gradually built up near the surface and exponentially declined with height. In contrast to the large variability found both in Hm and Cm, Cf stayed relatively unaffected through the day. Cf was less than 10 % of the ground level under clean conditions, while it amounted to half of the ground level in some polluted cases. In situ measurements of BC vertical profiles would hopefully have an important implication for

  16. Use of In Situ Cloud Condensation Nuclei, Extinction, and Aerosol Size Distribution Measurements to Test a Method for Retrieving Cloud Condensation Nuclei Profiles From Surface Measurements

    NASA Technical Reports Server (NTRS)

    Ghan, Stephen J.; Rissman, Tracey A.; Ellman, Robert; Ferrare, Richard A.; Turner, David; Flynn, Connor; Wang, Jian; Ogren, John; Hudson, James; Jonsson, Haflidi H.; VanReken, Timothy; Flagan, Richard C.; Seinfeld, John H.

    2006-01-01

    If the aerosol composition and size distribution below cloud are uniform, the vertical profile of cloud condensation nuclei (CCN) concentration can be retrieved entirely from surface measurements of CCN concentration and particle humidification function and surface-based retrievals of relative humidity and aerosol extinction or backscatter. This provides the potential for long-term measurements of CCN concentrations near cloud base. We have used a combination of aircraft, surface in situ, and surface remote sensing measurements to test various aspects of the retrieval scheme. Our analysis leads us to the following conclusions. The retrieval works better for supersaturations of 0.1% than for 1% because CCN concentrations at 0.1% are controlled by the same particles that control extinction and backscatter. If in situ measurements of extinction are used, the retrieval explains a majority of the CCN variance at high supersaturation for at least two and perhaps five of the eight flights examined. The retrieval of the vertical profile of the humidification factor is not the major limitation of the CCN retrieval scheme. Vertical structure in the aerosol size distribution and composition is the dominant source of error in the CCN retrieval, but this vertical structure is difficult to measure from remote sensing at visible wavelengths.

  17. The Cloud-Aerosol Transport System (CATS): A New Lidar for Aerosol and Cloud Profiling from the International Space Station

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; McGill, Mathew J.; Yorks. John E.; Hlavka, Dennis L.; Hart, William D.; Palm, Stephen P.; Colarco, Peter R.

    2012-01-01

    Spaceborne lidar profiling of aerosol and cloud layers has been successfully implemented during a number of prior missions, including LITE, ICESat, and CALIPSO. Each successive mission has added increased capability and further expanded the role of these unique measurements in wide variety of applications ranging from climate, to air quality, to special event monitoring (ie, volcanic plumes). Many researchers have come to rely on the availability of profile data from CALIPSO, especially data coincident with measurements from other A-Train sensors. The CALIOP lidar on CALIPSO continues to operate well as it enters its fifth year of operations. However, active instruments have more limited lifetimes than their passive counterparts, and we are faced with a potential gap in lidar profiling from space if the CALIOP lidar fails before a new mission is operational. The ATLID lidar on EarthCARE is not expected to launch until 2015 or later, and the lidar component of NASA's proposed Aerosols, Clouds, and Ecosystems (ACE) mission would not be until after 2020. Here we present a new aerosol and cloud lidar that was recently selected to provide profiling data from the International Space Station (ISS) starting in 2013. The Cloud-Aerosol Transport System (CATS) is a three wavelength (1064,532,355 nm) elastic backscatter lidar with HSRL capability at 532 nm. Depolarization measurements will be made at all wavelengths. The primary objective of CATS is to continue the CALIPSO aerosol and cloud profile data record, ideally with overlap between both missions and EarthCARE. In addition, the near real time (NRT) data capability ofthe ISS will enable CATS to support operational applications such as aerosol and air quality forecasting and special event monitoring. The HSRL channel will provide a demonstration of technology and a data testbed for direct extinction retrievals in support of ACE mission development. An overview of the instrument and mission will be provided, along with a

  18. Measurements of aerosol phase function and vertical backscattering coefficient using a charge-coupled device side-scatter lidar.

    PubMed

    Tao, Zongming; Liu, Dong; Wang, Zhenzhu; Ma, Xiaomin; Zhang, Qingze; Xie, Chenbo; Bo, Guangyu; Hu, Shunxing; Wang, Yingjian

    2014-01-13

    By using a charge-coupled device (CCD) as the detector, side-scatter lidar has great potential applications in the near range atmospheric detection. A new inversion method is proposed for CCD side-scatter lidar (Clidar) to retrieve aerosol phase function and vertical backscattering coefficient. Case studies show the retrieved results from Clidar are in good agreements with those obtained from other instruments. It indicates that the new proposed inversion method is reliable and feasible and that the Clidar is practicable.

  19. Lidar Observations of the Vertical Structure of Ozone and Aerosol during Wintertime High-Ozone Episodes Associated with Oil and Gas Exploration in the Uintah Basin

    NASA Astrophysics Data System (ADS)

    Senff, C. J.; Langford, A. O.; Banta, R. M.; Alvarez, R. J.; Weickmann, A.; Sandberg, S.; Marchbanks, R. D.; Brewer, A.; Hardesty, R. M.

    2013-12-01

    The Uintah Basin in northeast Utah has been experiencing extended periods of poor air quality in the winter months including very high levels of surface ozone. To investigate the causes of these wintertime ozone pollution episodes, two comprehensive studies were undertaken in January/February of 2012 and 2013. As part of these Uintah Basin Ozone Studies (UBOS), NOAA deployed its ground-based, scanning Tunable Optical Profiler for Aerosol and oZone (TOPAZ) lidar to document the vertical structure of ozone and aerosol backscatter from near the surface up to about 3 km above ground level (AGL). TOPAZ, along with a comprehensive set of chemistry and meteorological measurements, was situated in both years at the Horse Pool site at the northern edge of a large concentration of gas producing wells in the eastern part of the Uintah Basin. The 2012 study was characterized by unusually warm and snow-free condition and the TOPAZ lidar observed deep boundary layers (BL) and mostly well-mixed vertical ozone profiles at or slightly above tropospheric background levels. During UBOS 2013, winter weather conditions in the Uintah Basin were more typical with snow-covered ground and a persistent, shallow cold-pool layer. The TOPAZ lidar characterized with great temporal and spatial detail the evolution of multiple high-ozone episodes as well as cleanout events caused by the passage of synoptic-scale storm systems. Despite the snow cover, the TOPAZ observations show well-mixed afternoon ozone and aerosol profiles up to about 100 m AGL. After several days of pollutant buildup, BL ozone values reached 120-150 ppbv. Above the mixed layer, ozone values gradually decreased to tropospheric background values of around 50 ppbv throughout the several-hundred-meter-deep cold-pool layer and then stayed constant above that up to about 3 km AGL. During the ozone episodes, the lidar observations show no indication of either vertical or horizontal transport of high ozone levels to the surface, thus

  20. Investigating vertical distributions of ozone and of the aerosol extinction coefficient in the middle atmosphere with the MKS-M and SFN-4 instruments on board Salyut-7

    NASA Astrophysics Data System (ADS)

    Badaev, V. V.; Grechko, G. M.; Elanskii, N. F.; Kan, V.; Plotkin, M. E.

    1989-04-01

    The technical characteristics of the multichannel spectrometer (MKS-M) system combined with a camera containing a spectrophotography attachment (SFN-4) are discussed together with results obtained by this system on distributions of ozone and aerosol in the middle atmosphere. It is demonstrated that this system is capable of retrieving the fine structure of vertical ozone and aerosol extinction distributions in the lower stratosphere. Results show that, in the ozonosphere, the contents of ozone and of aerosol exhibit a negative correlation.

  1. Evaluating CALIOP Nighttime Level 2 Aerosol Profile Retrievals Using a Global Transport Model Equipped with Two-Dimensional Variational Data Assimilation and Ground-Based Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Campbell, J. R.; Tackett, J. L.; Reid, J. S.; Zhang, J.; Westphal, D. L.; Vaughan, M.; Winker, D. M.; Welton, E. J.; Prospero, J. M.; Shimizu, A.; Sugimoto, N.

    2011-12-01

    Launched in 2006, the Cloud Aerosol Lidar with Orthogonal Polarization instrument (CALIOP) flown aboard the NASA/CNES Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite has collected the first high-resolution global, inter-seasonal and multi-year measurements of aerosol structure. Profiles for aerosol particle extinction coefficient and column-integrated optical depth (AOD) are unique and highly synergistic satellite measurements, given the limitations of passive aerosol remote sensors from resolving information vertically. However, accurate value-added (Level 2.0) CALIOP aerosol products require comprehensive validation of retrieval techniques and calibration stability. Daytime Level 2.0 CALIOP AOD retrievals have been evaluated versus co-located NASA Moderate Resolution Imaging Spectroradiometer (MODIS-AQUA) data. To date, no corresponding investigation of nighttime retrieval performance has been conducted from a lack of requisite global nighttime validation datasets. In this paper, Version 3.01 CALIOP 5-km retrievals of nighttime 0.532 μm AOD from 2007 are evaluated versus corresponding 0.550 μm AOD analyses derived with the global 1° x 1° U. S. Navy Aerosol Analysis and Prediction System (NAAPS). Mean regional profiles of CALIOP nighttime 0.532 μm extinction coefficient are assessed versus NASA Micropulse Lidar Network and NIES Skynet Lidar Network measurements. NAAPS features a two-dimensional variational assimilation procedure for quality-assured MODIS and NASA Multi-angle Imaging Spectroradiometer (MISR) AOD products. Whereas NAAPS nighttime AOD datasets represent a nominal 12-hr forecast field, from lack of MODIS/MISR retrievals for assimilation in the dark sector of the model, evaluation of NAAPS 00-hr analysis and 24-hr forecast skill versus MODIS and NASA Aerosol Robotic Network (AERONET) indicates adequate stability for conducting this study. Corresponding daytime comparisons of CALIOP retrievals with NAAPS

  2. Low profile, high load vertical rolling positioning stage

    DOEpatents

    Shu, Deming; Barraza, Juan

    1996-01-01

    A stage or support platform assembly for use in a synchrotron accurately positions equipment to be used in the beam line of the synchrotron. The support platform assembly includes an outer housing in which is disposed a lifting mechanism having a lifting platform or stage at its upper extremity on which the equipment is mounted. A worm gear assembly is located in the housing and is adapted to raise and lower a lifting shaft that is fixed to the lifting platform by an anti-binding connection. The lifting platform is moved vertically as the lifting shaft is moved vertically. The anti-binding connection prevents the shaft from rotating with respect to the platform, but does permit slight canting of the shaft with respect to the lifting platform so as to eliminate binding and wear due to possible tolerance mismatches. In order to ensure that the lifting mechanism does not move in a horizontal direction as it is moved vertically, at least three linear roller bearing assemblies are arranged around the outer-periphery of the lifting mechanism. One of the linear roller bearing assemblies can be adjusted so that the roller bearings apply a loading force against the lifting mechanism. Alternatively, a cam mechanism can be used to provide such a loading force.

  3. Comparison of stratospheric aerosol and gas experiment I (SAGE I) and Umkehr ozone profiles including a search for Umkehr aerosol effects

    SciTech Connect

    Newchurch, M.J.

    1986-01-01

    After briefly reviewing ozone depletion predictions from atmospheric models and results from trend analysis of Umkehr data, this paper outlines the Umkehr method for deducing the vertical profile of ozone and reviews the theoretical and empirical studies of the aerosol effect on Umkehr measurements. A brief description of the Stratospheric Aerosol and Gas Experiment I (SAGE I) is followed by a method for approximating the best representation of the conditions over the Umkehr ground site as seen by the SAGE I satellite. Using a spatially weighted average of SAGE I events derived from an autocorrelation analysis, the authors find 337 co-located SAGE I and Umkehr events. The approximate total column ozone measured by SAGE I is 5% higher than that measured by Umkehr on average. Most of this difference resides in Umkehr layer two, three, and four, while layers seven, eight, and nine contain small differences in average ozone content. Intercomparison with four other ozone studies indicates agreement between SAGE I and SBUV in most layers and at most Umkehr stations north of 30/sup 0/. However, significant differences in Umkehr layer eight between SAGE I and SBUV remain. Ozone differences between SAGE I and Umkehr are strong functions of both total column ozone and season in the lower layers but not in the upper layers.

  4. Measuring the vertical distributions of the upper tropospheric and stratospheric dust with a LOAC aerosol counter under meteorological balloons

    NASA Astrophysics Data System (ADS)

    Vignelles, Damien; Renard, Jean-Baptiste; Berthet, Gwenael; Dulac, François; Coute, Benoit; Jeannot, Matthieu; Jegou, Fabrice; Olafsson, Haraldur; Dagsson Waldhauserova, Pavla

    2014-05-01

    France) and form Iceland. For this period of observation, the stratosphere is characterized by a 'background' aerosol content, i.e. free of any volcanic influence. In this context, we show that both liquid and solid particles are present, depending on the altitude and on the aerosol sizes. A series of one year of flight will be presented to highlight the trend in the aerosol content. Also, the analysis of individual profiles exhibits a strong variability in terms of concentration and composition both in the upper troposphere and in the stratosphere. Such variations are often linked with the aerosol composition. The reasons of such variability are investigated, in particular in terms of air mass origins and transport.

  5. Vertical Structure of the Wind Speed Profile at the North Sea Offshore Measurement Platform FINO1

    NASA Astrophysics Data System (ADS)

    Kettle, A. J.

    2013-12-01

    The vertical wind speed profile in the lowest 100m of the marine atmospheric boundary layer has been characterized from data collected at the FINO1 offshore research platform in the German North Sea sector for 2005. Located in 30m of water, the platform has a dense vertical array of meteorological instrumentation to measure wind speed, air temperature, relative humidity, and atmospheric turbulence characteristics. Along measurements of the ocean temperature and surface waves, the platform is well-equipped to characterize wind properties in the near-surface boundary layer. Preliminary analysis reveals a high incidence of vertical wind speed profiles that deviate significantly from Monin-Obukhov similarity theory with wind speed inflections that suggest decoupled layers near the surface. The presentation shows how the properties of the vertical wind speed profile change mainly depending on the wind speed, wind direction, and time of year. The results are significant because there are few reports of inflections in the vertical wind speed profile over the ocean and there is an a priori assumption that the vertical wind speed profile varies smoothly according to similarity theory. There are possible consequences for the wind energy development in terms of understanding the forces acting on offshore wind turbines whose rotors sweep across heights 150-200m above the sea surface.

  6. A New Rapid Method for Measuring the Vertical Head Profile.

    PubMed

    Keller, Carl

    2017-03-01

    This study describes a new technique for measuring the head profile in a geologic formation. The technique provides rapid, low cost information on the depth of water-producing zones and aquitards in heterogeneous aquifers, yielding estimates of hydraulic heads in each zone while identifying any potential for cross contamination between zones. The measurements can be performed in a typical borehole in just a few hours. The procedure uses both the continuous transmissivity profile obtained by the installation (eversion) of a flexible borehole liner into an open borehole and the subsequent removal (inversion) of the same liner from the borehole. The method is possible because of the continuous transmissivity profile (T profile described by Keller et al. 2014) obtained by measuring the rate of liner eversion under a constant driving head. The hydraulic heads of producing zones are measured using the reverse head profile (RHP) method (patent no. 9,008,971) based on a stepwise inversion of the borehole liner. As each interval of the borehole is uncovered by inversion of the liner, the head beneath the liner is allowed to equilibrate to a steady-state value. The individual hydraulic heads contributing to each measurement are calculated using the measured transmissivity for each zone. Application of the RHP method to a sedimentary bedrock borehole in New Jersey verified that it reproduced the head distribution obtained the same day in the same borehole instrumented with a multilevel sampling system.

  7. Perception of facial profile attractiveness of different antero-posterior and vertical proportions.

    PubMed

    Abu Arqoub, Sarah H; Al-Khateeb, Susan N

    2011-02-01

    This study investigated the influence of changing the antero-posterior (AP) and vertical proportions of the lower face on the rankings of facial attractiveness. Four hundred and fifty-four (219 males and 235 females) native Jordanians of various ages and professions rated the attractiveness of a sequence of antero-posteriorly and vertically altered male and female profile images. Attractiveness ranking scores were obtained from the visual assessment of these digitally altered male and female profile images that represented a range of AP and vertical lower facial proportions. The mean and standard deviation (SD) for the rank scores were calculated. Statistical analyses were employed for comparison between the different age groups, genders, and professions. A Class I male profile with a normal lower face height and Class I female profile with a reduced lower face height were ranked as the most attractive. Class II male and female profiles with increased lower face heights were ranked as least attractive. As the vertical and AP dimensions diverged from normal, attractiveness decreased. Images with Class II profile features and increased lower face heights were considered less attractive than corresponding images with Class III profile features and reduced lower face heights. Gender had a limited influence on the perception of attractiveness. A significant difference was found between dentists and lay people in the perception of profile attractiveness.

  8. Evaluation of modeled vertical aerosol distributions over east-Asia using in-situ and satellite data during summer 2008

    NASA Astrophysics Data System (ADS)

    Quennehen, Boris; Raut, Jean-Christophe; Law, Kathy S.; Thomas, Jennie L.; Ancellet, Gérard; Bazureau, Ariane; Daskalakis, Nikos; Kim, Sang-Woo; Yoon, Soon-Chang; Zhu, Tong; Pelon, Jacques

    2013-04-01

    As part of the EU ECLIPSE project, which aims to quantify the climate impact of short lived climate forcers (SLCFs), including aerosols, black carbon and ozone, regional models are being used to evaluate global model performance for specific case studies. Here, we present results using regional WRF-Chem simulations over east-Asia. Results are compared to data from field campaigns which took place in summer 2008 and from long-term measurement stations. This study will, in a first step, evaluate the ability of the model to simulate aerosol physical, chemical and optical properties, with a focus on pollution layers. In a second step, the radiative impact of such layers over east-Asia will be investigated as a function of their position relative to clouds. The WRF-Chem regional model was run using MOZART gas phase chemistry and the MOSAIC aerosol scheme and was evaluated against available measurements for the period August to September 2008. The model was run using ECLIPSE anthropogenic and GFEDv3.1 fire emissions for 2008, while initial and boundary conditions were specified from the TM4 global chemical transport model. The radiative impact of pollution aerosol layers has already been investigated but less is known about the influence of vertical layering in the atmosphere. Such layers might have different radiative impacts whether they are below or above clouds and in that sense, a better understanding of their spatial extent is critical. Information about pollution aerosol layers and clouds optical properties and positions over East-Asia are determined using observations from CALIPSO. The radiative impact of these layers is simulated and compared to the observations. In addition to satellite observations, model results are evaluated against trace gas and aerosol data from aircraft campaigns over eastern Asia in summer 2008 (e.g., CAREBEIJING and CAPMEX) and ground-based measurements (e.g., NIES and ABC). In this study, we assess aerosol total concentrations and size

  9. Use of temperature profiles beneath streams to determine rates of vertical ground-water flow and vertical hydraulic conductivity

    USGS Publications Warehouse

    Lapham, Wayne W.

    1989-01-01

    The use of temperature profiles beneath streams to determine rates of vertical ground-water flow and effective vertical hydraulic conductivity of sediments was evaluated at three field sites by use of a model that numerically solves the partial differential equation governing simultaneous vertical flow of fluid and heat in the Earth. The field sites are located in Hardwick and New Braintree, Mass., and in Dover, N.J. In New England, stream temperature varies from about 0 to 25 ?C (degrees Celsius) during the year. This stream-temperature fluctuation causes ground-water temperatures beneath streams to fluctuate by more than 0.1 ?C during a year to a depth of about 35 ft (feet) in fine-grained sediments and to a depth of about 50 ft in coarse-grained sediments, if ground-water velocity is 0 ft/d (foot per day). Upward flow decreases the depth affected by stream-temperature fluctuation, and downward flow increases the depth. At the site in Hardwick, Mass., ground-water flow was upward at a rate of less than 0.01 ft/d. The maximum effective vertical hydraulic conductivity of the sediments underlying this site is 0.1 ft/d. Ground-water velocities determined at three locations at the site in New Braintree, Mass., where ground water discharges naturally from the underlying aquifer to the Ware River, ranged from 0.10 to 0.20 ft/d upward. The effective vertical hydraulic conductivity of the sediments underlying this site ranged from 2.4 to 17.1 ft/d. Ground-water velocities determined at three locations at the Dover, N.J., site, where infiltration from the Rockaway River into the underlying sediments occurs because of pumping, were 1.5 ft/d downward. The effective vertical hydraulic conductivity of the sediments underlying this site ranged from 2.2 to 2.5 ft/d. Independent estimates of velocity at two of the three sites are in general agreement with the velocities determined using temperature profiles. The estimates of velocities and conductivities derived from the

  10. Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations

    NASA Astrophysics Data System (ADS)

    Jähn, Michael; Muñoz-Esparza, Domingo; Chouza, Fernando; Reitebuch, Oliver; Knoth, Oswald; Haarig, Moritz; Ansmann, Albert; Tegen, Ina

    2016-04-01

    Large eddy simulations (LESs) with ASAM (All Scale Atmospheric Model) are performed for the area of the Caribbean island Barbados to investigate island effects on boundary layer modification, cloud generation and vertical mixing of aerosols. In order to generate inflow turbulence consistent with the upstream marine boundary layer forcing, we use the cell perturbation method based on finite amplitude potential temperature perturbations. This method is now also validated for moist boundary layer simulations with open lateral boundary conditions. Observational data obtained from the SALTRACE (Saharan Aerosol Long-range Transport and Aerosol-Cloud-Interaction Experiment) field campaign is used for both model initialization and comparisons. Several sensitivity tests are carried out to demonstrate the problems related to "gray zone modeling" or when the turbulent marine boundary layer flow is replaced by laminar winds. Additional simulation cases deal with modified surface characteristics and their impacts on the simulation results. Saharan dust layers that reach Barbados via long-range transport over the North Atlantic are included as passive tracers in the model. Effects of layer thinning, subsidence and turbulent downward transport near the layer bottom at z ≈ 1800 m become apparent. The exact position of these layers 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 lidar data show similarities in the downwind vertical wind structure and accurately reproduces the development of the daytime convective boundary layer measured by the Raman lidar.

  11. Vertical profile of tritium concentration in air during a chronic atmospheric HT release.

    PubMed

    Noguchi, Hiroshi; Yokoyama, Sumi

    2003-03-01

    The vertical profiles of tritium gas and tritiated water concentrations in air, which would have an influence on the assessment of tritium doses as well as on the environmental monitoring of tritium, were measured in a chronic tritium gas release experiment performed in Canada in 1994. While both of the profiles were rather uniform during the day because of atmospheric mixing, large gradients of the profiles were observed at night. The gradient coefficients of the profiles were derived from the measurements. Correlations were analyzed between the gradient coefficients and meteorological conditions: solar radiation, wind speed, and turbulent diffusivity. It was found that the solar radiation was highly correlated with the gradient coefficients of tritium gas and tritiated water profiles and that the wind speed and turbulent diffusivity showed weaker correlations with those of tritiated water profiles. A one-dimensional tritium transport model was developed to analyze the vertical diffusion of tritiated water re-emitted from the ground into the atmosphere. The model consists of processes of tritium gas deposition to soil including oxidation into tritiated water, reemission of tritiated water, dilution of tritiated water in soil by rain, and vertical diffusion of tritiated water in the atmosphere. The model accurately represents the accumulation of tritiated water in soil water and the time variations and vertical profiles of tritiated water concentrations in air.

  12. Measurements of Stratospheric Pinatubo Aerosol Extinction Profiles by a Raman Lidar

    NASA Technical Reports Server (NTRS)

    Abo, Makoto; Nagasawa, Chikao

    1992-01-01

    The Raman lidar has been used for remote measurements of water vapor, ozone and atmospheric temperature in the lower troposphere because the Raman cross section is three orders smaller than the Rayleigh cross section. We estimated the extinction coefficients of the Pinatubo volcanic aerosol in the stratosphere using a Raman lidar. If the precise aerosol extinction coefficients are derived, the backscatter coefficient of a Mie scattering lidar will be more accurately estimated. The Raman lidar has performed to measure density profiles of some species using Raman scattering. Here we used a frequency-doubled Nd:YAG laser for transmitter and received nitrogen vibrational Q-branch Raman scattering signal. Ansmann et al. (1990) derived tropospherical aerosol extinction profiles with a Raman lidar. We think that this method can apply to dense stratospheric aerosols such as Pinatubo volcanic aerosols. As dense aerosols are now accumulated in the stratosphere by Pinatubo volcanic eruption, the error of Ramen lidar signal regarding the fluctuation of air density can be ignored.

  13. Aerosols

    Atmospheric Science Data Center

    2013-04-17

    ... article title:  Aerosols over Central and Eastern Europe     View Larger Image ... last weeks of March 2003, widespread aerosol pollution over Europe was detected by several satellite-borne instruments. The Multi-angle ...

  14. Profile and Morphology of Fungal Aerosols Characterized by Field Emission Scanning Electron Microscopy (FESEM)

    PubMed Central

    Afanou, Komlavi Anani; Straumfors, Anne; Skogstad, Asbjørn; Skaar, Ida; Hjeljord, Linda; Skare, Øivind; Green, Brett James; Tronsmo, Arne; Eduard, Wijnand

    2016-01-01

    Fungal aerosols consist of spores and fragments with diverse array of morphologies; however, the size, shape, and origin of the constituents require further characterization. In this study, we characterize the profile of aerosols generated from Aspergillus fumigatus, A. versicolor, and Penicillium chrysogenum grown for 8 weeks on gypsum boards. Fungal particles were aerosolized at 12 and 20 L min−1 using the Fungal Spore Source Strength Tester (FSSST) and the Stami particle generator (SPG). Collected particles were analyzed with field emission scanning electron microscopy (FESEM). We observed spore particle fraction consisting of single spores and spore aggregates in four size categories, and a fragment fraction that contained submicronic fragments and three size categories of larger fragments. Single spores dominated the aerosols from A. fumigatus (median: 53%), while the submicronic fragment fraction was the highest in the aerosols collected from A. versicolor (median: 34%) and P. chrysogenum (median: 31%). Morphological characteristics showed near spherical particles that were only single spores, oblong particles that comprise some spore aggregates and fragments (<3.5 μm), and fiber-like particles that regroup chained spore aggregates and fragments (>3.5 μm). Further, the near spherical particles dominated the aerosols from A. fumigatus (median: 53%), while oblong particles were dominant in the aerosols from A. versicolor (68%) and P. chrysogenum (55%). Fiber-like particles represented 21% and 24% of the aerosols from A. versicolor and P. chrysogenum, respectively. This study shows that fungal particles of various size, shape, and origin are aerosolized, and supports the need to include a broader range of particle types in fungal exposure assessment. PMID:26855468

  15. Profile and Morphology of Fungal Aerosols Characterized by Field Emission Scanning Electron Microscopy (FESEM).

    PubMed

    Afanou, Komlavi Anani; Straumfors, Anne; Skogstad, Asbjørn; Skaar, Ida; Hjeljord, Linda; Skare, Øivind; Green, Brett James; Tronsmo, Arne; Eduard, Wijnand

    Fungal aerosols consist of spores and fragments with diverse array of morphologies; however, the size, shape, and origin of the constituents require further characterization. In this study, we characterize the profile of aerosols generated from Aspergillus fumigatus, A. versicolor, and Penicillium chrysogenum grown for 8 weeks on gypsum boards. Fungal particles were aerosolized at 12 and 20 L min(-1) using the Fungal Spore Source Strength Tester (FSSST) and the Stami particle generator (SPG). Collected particles were analyzed with field emission scanning electron microscopy (FESEM). We observed spore particle fraction consisting of single spores and spore aggregates in four size categories, and a fragment fraction that contained submicronic fragments and three size categories of larger fragments. Single spores dominated the aerosols from A. fumigatus (median: 53%), while the submicronic fragment fraction was the highest in the aerosols collected from A. versicolor (median: 34%) and P. chrysogenum (median: 31%). Morphological characteristics showed near spherical particles that were only single spores, oblong particles that comprise some spore aggregates and fragments (<3.5 μm), and fiber-like particles that regroup chained spore aggregates and fragments (>3.5 μm). Further, the near spherical particles dominated the aerosols from A. fumigatus (median: 53%), while oblong particles were dominant in the aerosols from A. versicolor (68%) and P. chrysogenum (55%). Fiber-like particles represented 21% and 24% of the aerosols from A. versicolor and P. chrysogenum, respectively. This study shows that fungal particles of various size, shape, and origin are aerosolized, and supports the need to include a broader range of particle types in fungal exposure assessment.

  16. Profiling the PM2.5 mass concentration vertical distribution in the boundary layer

    NASA Astrophysics Data System (ADS)

    Tao, Z.; Wang, Z.; Yang, S.; Shan, H.; Ma, X.; Zhang, H.; Zhao, S.; Liu, D.; Xie, C.; Wang, Y.

    2015-12-01

    Fine particle (PM2.5) affects human life and activities directly; the detection of PM2.5 mass concentration profile is very essential due to its practical and scientific meanings (such as, quantifying of air quality and its variability, and improving air quality forecast and assessment). But so far, it is difficult to detect PM2.5 mass concentration profile. The proposed methodology to study the relationship between aerosol extinction coefficient and PM2.5 mass concentration is described, which indicates that the PM2.5 mass concentration profile could be retrieved by combining a charge-coupled device (CCD) side-scatter lidar and a PM2.5 sampling detector. When the relative humidity is less than 70 %, PM2.5 mass concentration is proportional to aerosol extinction coefficient, and then the specific coefficient can be calculated. Using this specific coefficient, aerosol extinction profile is converted to PM2.5 mass concentration profile. Three cases of clean night (on 21 September 2014), pollutant night (on 17 March 2014), and heavy pollutant night (on 13 February 2015) are studied. The characteristic of PM2.5 mass concentration profile in near-ground during these three nights' cases in the western suburb of Hefei city was discussed. The PM2.5 air pollutant concentration is comparatively large in close surface varying with time and altitude. The experiment results show that the CCD side-scatter lidar combined with a PM2.5 detector is an effective and new method to explore pollutant mass concentration profile in near-ground.

  17. Profiling the PM2.5 mass concentration vertical distribution in the boundary layer

    NASA Astrophysics Data System (ADS)

    Tao, Zongming; Wang, Zhenzhu; Yang, Shijun; Shan, Huihui; Ma, Xiaomin; Zhang, Hui; Zhao, Sugui; Liu, Dong; Xie, Chenbo; Wang, Yingjian

    2016-04-01

    Fine particles (PM2.5) affect human life and activities directly; the detection of PM2.5 mass concentration profile is very essential due to its practical and scientific significance (such as the quantification of air quality and its variability as well as the assessment of improving air quality forecast). But so far, it has been difficult to detect PM2.5 mass concentration profile. The proposed methodology to study the relationship between aerosol extinction coefficient and PM2.5 mass concentration is described, which indicates that the PM2.5 mass concentration profile could be retrieved by combining a charge-coupled device (CCD) side-scatter lidar with a PM2.5 sampling detector. When the relative humidity is less than 70 %, PM2.5, mass concentration is proportional to the aerosol extinction coefficient, and then the specific coefficient can be calculated. Through this specific coefficient, aerosol extinction profile is converted to PM2.5 mass concentration profile. Three cases of clean night (on 21 September 2014), pollutant night (on 17 March 2014), and heavy pollutant night (on 13 February 2015) are studied. The characteristics of PM2.5 mass concentration profile at the near-ground level during the cases of these 3 nights in the western suburb of Hefei city were discussed. The PM2.5 air pollutant concentration is comparatively large close to the surface and varies with time and altitude. The experiment results show that the CCD side-scatter lidar combined with a PM2.5 detector is an effective and new method to explore pollutant mass concentration profile at the near-ground level.

  18. Vertical Transport of Aerosol Particles across Mountain Topography near the Los Angeles Basin

    NASA Astrophysics Data System (ADS)

    Murray, J. J.; Schill, S.; Freeman, S.; Bertram, T. H.; Lefer, B. L.

    2015-12-01

    Transport of aerosol particles is known to affect air quality and is largely dependent on the characteristic topography of the surrounding region. To characterize this transport, aerosol number distributions were collected with an Ultra-High Sensitivity Aerosol Spectrometer (UHSAS, DMT) during the 2015 NASA Student Airborne Research Program (SARP) in and around the Los Angeles Basin in Southern California. Increases in particle number concentration and size were observed over mountainous terrain north of Los Angeles County. Chemical analysis and meteorological lagrangian trajectories suggest orographic lifting processes, known as the "chimney effect". Implications for spatial transport and distribution will be discussed.

  19. CALIBRATION OF A VERTICAL-SCAN LONG TRACE PROFILER AT MSFC.

    SciTech Connect

    GUBAREV,M.; KESTER,T.; TAKACS,P.Z.

    2001-07-31

    The long trace profiler (LTP) is the instrument of choice for the surface figure measurement of grazing incidence mirrors. The modification of conventional LTP, the vertical-scan LTP, capable of measuring the surface figure of replicated shell mirrors is now in operation at Marshall Space Flight Center. A few sources of systematic error for vertical-scan LTP are discussed. Status of systematic error reduction is reported.

  20. Profiling of aerosol microphysical properties at several EARLINET/AERONET sites during the July 2012 ChArMEx/EMEP campaign

    NASA Astrophysics Data System (ADS)

    José Granados-Muñoz, María; Navas-Guzmán, Francisco; Guerrero-Rascado, Juan Luis; Bravo-Aranda, Juan Antonio; Binietoglou, Ioannis; Nepomuceno Pereira, Sergio; Basart, Sara; María Baldasano, José; Belegante, Livio; Chaikovsky, Anatoli; Comerón, Adolfo; D'Amico, Giuseppe; Dubovik, Oleg; Ilic, Luka; Kokkalis, Panos; Muñoz-Porcar, Constantino; Nickovic, Slobodan; Nicolae, Doina; José Olmo, Francisco; Papayannis, Alexander; Pappalardo, Gelsomina; Rodríguez, Alejandro; Schepanski, Kerstin; Sicard, Michaël; Vukovic, Ana; Wandinger, Ulla; Dulac, François; Alados-Arboledas, Lucas

    2016-06-01

    The simultaneous analysis of aerosol microphysical properties profiles at different European stations is made in the framework of the ChArMEx/EMEP 2012 field campaign (9-11 July 2012). During and in support of this campaign, five lidar ground-based stations (Athens, Barcelona, Bucharest, Évora, and Granada) performed 72 h of continuous lidar measurements and collocated and coincident sun-photometer measurements. Therefore it was possible to retrieve volume concentration profiles with the Lidar Radiometer Inversion Code (LIRIC). Results indicated the presence of a mineral dust plume affecting the western Mediterranean region (mainly the Granada station), whereas a different aerosol plume was observed over the Balkans area. LIRIC profiles showed a predominance of coarse spheroid particles above Granada, as expected for mineral dust, and an aerosol plume composed mainly of fine and coarse spherical particles above Athens and Bucharest. Due to the exceptional characteristics of the ChArMEx database, the analysis of the microphysical properties profiles' temporal evolution was also possible. An in-depth analysis was performed mainly at the Granada station because of the availability of continuous lidar measurements and frequent AERONET inversion retrievals. The analysis at Granada was of special interest since the station was affected by mineral dust during the complete analyzed period. LIRIC was found to be a very useful tool for performing continuous monitoring of mineral dust, allowing for the analysis of the dynamics of the dust event in the vertical and temporal coordinates. Results obtained here illustrate the importance of having collocated and simultaneous advanced lidar and sun-photometer measurements in order to characterize the aerosol microphysical properties in both the vertical and temporal coordinates at a regional scale. In addition, this study revealed that the use of the depolarization information as input in LIRIC in the stations of Bucharest,

  1. Tropospheric mercury vertical profiles between 500 and 10 000 m in central Europe

    NASA Astrophysics Data System (ADS)

    Weigelt, Andreas; Ebinghaus, Ralf; Pirrone, Nicola; Bieser, Johannes; Bödewadt, Jan; Esposito, Giulio; Slemr, Franz; van Velthoven, Peter F. J.; Zahn, Andreas; Ziereis, Helmut

    2016-03-01

    The knowledge of the vertical distribution of atmospheric mercury (Hg) plays an important role in determining the transport and cycling of mercury. However, measurements of the vertical distribution are rare, because airborne measurements are expensive and labour intensive. Consequently, only a few vertical Hg profile measurements have been reported since the 1970s. Besides the Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container (CARIBIC) observations, the latest vertical profile over Europe was measured in 1996. Within the Global Mercury Observation System (GMOS) project, four vertical profiles were taken on board research aircraft (CASA-212) in August 2013 in background air over different locations in Slovenia and Germany. Each vertical profile consists of at least seven 5 min horizontal flight sections from 500 m above ground to 3000 m a.s.l. Gaseous elemental mercury (GEM) and total gaseous mercury (TGM) were measured with Tekran 2537X and Tekran 2537B analysers. In addition to the mercury measurements, SO2, CO, O3, NO, and NO2, basic meteorological parameters (pressure, temperature, relative humidity) have been measured. Additional ground-based mercury measurements at the GMOS master site in Waldhof, Germany and measurements onboard the CARIBIC passenger aircraft were used to extend the profile to the ground and upper troposphere respectively. No vertical gradient was found inside the well-mixed boundary layer (variation of less than 0.1 ng m-3) at different sites, with GEM varying from location to location between 1.4 and 1.6 ng m-3 (standard temperature and pressure, STP: T = 273.15 K, p = 1013.25 hPa). At all locations GEM dropped to 1.3 ng m-3 (STP) when entering the free troposphere and remained constant at higher altitudes. The combination of the vertical profile, measured on 21 August 2013 over Leipzig, Germany, with the CARIBIC measurements during ascent and descent to Frankfurt Airport, Germany, taken at

  2. An analysis of the vertical structure equation for arbitrary thermal profiles

    NASA Technical Reports Server (NTRS)

    Cohn, Stephen E.; Dee, Dick P.

    1987-01-01

    The vertical structure equation is a singular Sturm-Liouville problem whose eigenfunctions describe the vertical dependence of the normal modes of the primitive equations linearized about a given thermal profile. The eigenvalues give the equivalent depths of the modes. The spectrum of the vertical structure equation and the appropriateness of various upper boundary conditions, both for arbitrary thermal profiles were studied. The results depend critically upon whether or not the thermal profile is such that the basic state atmosphere is bounded. In the case of a bounded atmosphere it is shown that the spectrum is always totally discrete, regardless of details of the thermal profile. For the barotropic equivalent depth, which corresponds to the lowest eigen value, upper and lower bounds which depend only on the surface temperature and the atmosphere height were obtained. All eigenfunctions are bounded, but always have unbounded first derivatives. It was proved that the commonly invoked upper boundary condition that vertical velocity must vanish as pressure tends to zero, as well as a number of alternative conditions, is well posed. It was concluded that the vertical structure equation always has a totally discrete spectrum under the assumptions implicit in the primitive equations.

  3. Generation of optimum vertical profiles for an advanced flight management system

    NASA Technical Reports Server (NTRS)

    Sorensen, J. A.; Waters, M. H.

    1981-01-01

    Algorithms for generating minimum fuel or minimum cost vertical profiles are derived and examined. The option for fixing the time of flight is included in the concepts developed. These algorithms form the basis for the design of an advanced on-board flight management system. The variations in the optimum vertical profiles (resulting from these concepts) due to variations in wind, takeoff mass, and range-to-destination are presented. Fuel savings due to optimum climb, free cruise altitude, and absorbing delays enroute are examined.

  4. Tropospheric mercury vertical profiles between 500 and 10 000 m in central Europe

    NASA Astrophysics Data System (ADS)

    Weigelt, A.; Ebinghaus, R.; Pirrone, N.; Bieser, J.; Bödewadt, J.; Esposito, G.; Slemr, F.; van Velthoven, P. F. J.; Zahn, A.; Ziereis, H.

    2015-10-01

    Measurements of the vertical distribution of atmospheric mercury (Hg) are rare, because airborne measurements are expensive and labour intensive. Consequently, only a few vertical Hg profile measurements have been reported since the 1970s. Besides the CARIBIC passenger aircraft observations, the latest vertical profile over Europe was measured in 1996. Within the Global Mercury Observation System (GMOS) project four vertical profiles were taken on board research aircraft (CASA-212) in August 2013 in background air over different locations in Slovenia and Germany. Each vertical profile consists of at least seven 5 min horizontal flight sections from 500 m above ground to 3000 m a.s.l. Gaseous elemental mercury (GEM) was measured with a Tekran 2537X analyser and a Lumex RA-915-AM. Total gaseous mercury (TGM) was measured using a Tekran 2537B analyser and gaseous oxidized mercury (GOM) was sampled onto 8 denuders for post flight analysis (one for each profile, three during the transfer flights, and two blanks). In addition to the mercury measurements, SO2, CO, O3, NO, NO2, as well as basic meteorological parameters (pressure, temperature, relative humidity) have been measured. Additional ground based speciated mercury measurements at the GMOS master site in Waldhof (Germany) were used to extend the profile to the ground. No vertical gradient was found inside the well mixed boundary layer (variation by less than 0.1 ng m-3) at different sites with GEM varying from location to location between 1.4 and 1.6 ng m-3 (STP; standard conditions: p = 1013.25 hPa, T = 273.15 K). At all locations GEM dropped to 1.3 ng m-3 (STP) when entering the free troposphere and remained constant at higher altitudes. The combination of the vertical profile, measured on 21 August 2013, over Leipzig (Germany) with the CARIBIC measurements during ascent and descent to Frankfurt airport (Germany) at approximately the same time provide a unique central European vertical profile from inside the

  5. Measurements of the vertical profile of water vapor abundance in the Martian atmosphere from Mars Observer

    NASA Technical Reports Server (NTRS)

    Schofield, J. T.; Mccleese, Daniel J.

    1988-01-01

    An analysis is presented of the Pressure Modulator Infrared Radiometer (PMIRR) capabilities along with how the vertical profiles of water vapor will be obtained. The PMIRR will employ filter and pressure modulation radiometry using nine spectral channels, in both limb scanning and nadir sounding modes, to obtain daily, global maps of temperature, dust extinction, condensate extinction, and water vapor mixing ratio profiles as a function of pressure to half scale height or 5 km vertical resolution. Surface thermal properties will also be mapped, and the polar radiactive balance will be monitored.

  6. Validation of GOMOS vertical profiles using the stratospheric balloon-borne AMON and SALOMON UV-Visible spectrometers

    NASA Astrophysics Data System (ADS)

    Renard, J. B.; Chartier, M.; Berthet, G.; Robert, C.; Lemaire, T.; Pepe, F.; George, M.; Pirre, M.

    2003-04-01

    The stratospheric balloon-borne UV-visible spectrometers AMON and SALOMON, which uses stars and Moon as light source, respectively, were involved in the validation of the UV-visible spectrometer GOMOS onboard ENVISAT, which uses also stars as light source. A low spectral resolution UV-visible spectrometer, AMON-RA, is also implanted in the AMON gondola, for the validation of the GOMOS algorithm dedicated to the correction of the chromatic scintillation effect. A flight of SALOMON occurred in September 19, 2002, at mid latitude from Aire sur l’Adour, France. The night-time SALOMON and GOMOS measurements were conducted at the same time (around 21h30 TU) and with a spatial coincidence less than 250 km. Comparison of vertical profiles was done for an altitude in the 15-40 km range. While the global shape of the GOMOS and SALOMON ozone profiles are quite in agreement, the GOMOS NO2 and NO3 profiles are unrealistic when compared to SALOMON profiles. A reanalysis of the GOMOS transmission using algorithms already developed for SALOMON shows that accurate NO2 and NO3 profiles can be retrieved if DOAS technique and dedicated spectral windows are used. An AMON (and AMON-RA) flight and a new SALOMON flight should occurred at high latitude from Kiruna (northern Sweden) in January and March 2003, respectively. The same analyses as for the September 2002 flight will be conducted, including this time the OClO and aerosols extinction coefficient retrievals. Taking into account the effect of the chromatic scintillation on the transmission spectra, recommendations will be proposed in order to improve the GOMOS retrievals.

  7. Computer programs for generation and evaluation of near-optimum vertical flight profiles

    NASA Technical Reports Server (NTRS)

    Sorensen, J. A.; Waters, M. H.; Patmore, L. C.

    1983-01-01

    Two extensive computer programs were developed. The first, called OPTIM, generates a reference near-optimum vertical profile, and it contains control options so that the effects of various flight constraints on cost performance can be examined. The second, called TRAGEN, is used to simulate an aircraft flying along an optimum or any other vertical reference profile. TRAGEN is used to verify OPTIM's output, examine the effects of uncertainty in the values of parameters (such as prevailing wind) which govern the optimum profile, or compare the cost performance of profiles generated by different techniques. A general description of these programs, the efforts to add special features to them, and sample results of their usage are presented.

  8. An investigation of vertical winds obtained from vertically pointing and tilted beams of a five-beam 915-MHz wind profiler

    NASA Astrophysics Data System (ADS)

    Coulter, R. L.; Martin, T. J.

    The Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program has operated a 915-MHz radar wind profiler coupled with a Radio Acoustic Sounding System (RASS) since November 1992 at its Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) central facility in north central Oklahoma. The system is designed to provide continuous wind profiles from near the surface (100 m) to 5 km or more and virtual temperature profiles from near the surface to 1.5 km. During normal operation, the system uses four tilted beams (two each in the north-south and east-west vertical planes) and a single vertical beam to determine mean wind and virtual temperature profiles every hour. In this paper we illustrate and compare different methods for calculating w and several statistical variables from profiler data. The results are compared with those derived when the profiler is operated in a vertical-only mode under similar conditions.

  9. FAME-C: Retrieval of cloud top pressure with vertically inhomogeneous cloud profiles

    NASA Astrophysics Data System (ADS)

    Henken, Cintia Carbajal; Lindstrot, Rasmus; Filipitsch, Florian; Walther, Andi; Preusker, Rene; Fischer, Jürgen

    2013-05-01

    A synergistic FAME-C (Freie Universität Berlin AATSR-MERIS Cloud Retrieval) algorithm is developed within the frame of the ESA CCI Cloud project. Within FAME-C the ratio of two MERIS measurements (the Oxygen-A absorption channel and a window channel) is used to retrieve cloud top pressure. In case of high, extended clouds the retrieved cloud top pressure is generally too high. This can be understood as an overestimation of extinction in upper cloud layers due to the assumption of vertical homogeneous clouds in the radiative transfer simulations. To include more realistic cloud vertical profiles, one year of data from the Cloud Profiling Radar (CPR) onboard CloudSat has been used to determine average normalized cloud vertical extinction profiles with a fixed pressure thickness for nine cloud types. The nine cloud types are based on the ISCCP COT-CTP classification table. The retrieved cloud top pressure, now using CloudSat cloud profiles in the forward model, is compared to CPR reflectivities as well as the retrieved cloud top pressure using vertically homogeneous cloud profiles. In the first number of cases under examination the overestimation of cloud top pressure, and therefore the bias, is reduced by a large amount when using CloudSat vertical cloud profiles. Another advantage is that no assumption about the cloud geometrical thickness has to be made in the new retrieval. It should be noted that comparisons between FAME-C products and A-train products can only be made at high latitudes where A-train and ENVISAT have overlapping overflights.

  10. Carbon monoxide (CO) vertical profiles derived from joined TES and MLS measurements

    NASA Astrophysics Data System (ADS)

    Luo, Ming; Read, William; Kulawik, Susan; Worden, John; Livesey, Nathaniel; Bowman, Kevin; Herman, Robert

    2013-09-01

    (Tropospheric Emission Spectrometer) nadir and MLS (Microwave Limb Sounder) limb measurements from the Aura satellite are used to jointly estimate an atmospheric carbon monoxide (CO) profile with extended vertical range compared to profiles retrieved from the individual measurement. We describe the algorithms, the processing procedures, the prototyping results, and the evaluations for this new joint product. TES and MLS "stand-alone" CO profile retrievals are largely complementary, with TES being largely sensitive to lower to middle troposphere while MLS measures CO in the upper troposphere and above. We pair TES nadir and MLS limb tangent locations within 6-8 min and within 220 km. The paired radiance measurements of the two instruments in each location are optimally combined to retrieve a single CO profile along with other trace gases whose signal interferes with that from CO. This combined CO profile has a vertical resolution and vertical range that is an improvement over the two stand-alone products, especially in the upper troposphere/lower stratosphere. For example, the degrees of freedom for signal (DOFS) between surface and 50 hPa for TES alone are < 2, and for the combined CO profiles are 2-4. This new Aura CO product will be made available to the public using TES V005 and MLS V003 processing results and will provide a unique data set for studying tropospheric transport of air pollutants and troposphere-stratospheric exchange processes.

  11. Seasonal Variations in Titan's Stratosphere Observed with Cassini/CIRS: Temperature, Trace Molecular Gas and Aerosol Mixing Ratio Profiles

    NASA Technical Reports Server (NTRS)

    Vinatier, S.; Bezard, B.; Anderson, C. M.; Coustenis, A.; Teanby, N.

    2012-01-01

    Titan's northern spring equinox occurred in August 2009. General Circulation Models (e.g. Lebonnois et al., 2012) predict strong modifications of the global circulation in this period, with formation of two circulation cells instead of the pole-to-pole cell that occurred during northern winter. This winter single cell, which had its descending branch at the north pole, was at the origin of the enrichment of molecular abundances and high stratopause temperatures observed by Cassini/CIRS at high northern latitudes (e.g. Achterberg et al., 2011, Coustenis et al., 2010, Teanby et al., 2008, Vinatier et al., 2010). The predicted dynamical seasonal variations after the equinox have strong impact on the spatial distributions of trace gas, temperature and aerosol abundances. We will present here an analysis of CIRS limb-geometry datasets acquired in 2010 and 2011 that we used to monitor the seasonal evolution of the vertical profiles of temperature, molecular (C2H2, C2H6, HCN, ..) and aerosol abundances.

  12. Spatial and temporal variabilities in vertical structure of the Marine Atmospheric Boundary Layer over Bay of Bengal during Winter Phase of Integrated Campaign for Aerosols, gases and Radiation Budget

    NASA Astrophysics Data System (ADS)

    Subrahamanyam, D. Bala; Anurose, T. J.; Kumar, N. V. P. Kiran; Mohan, Mannil; Kunhikrishnan, P. K.; John, Sherine Rachel; Prijith, S. S.; Dutt, C. B. S.

    2012-04-01

    Spatial and temporal variabilities in the vertical structure of Marine Atmospheric Boundary Layer (MABL) over the Bay of Bengal (BoB) are investigated through a ship-borne field experiment measurements pertaining to three different classes, namely: night, morning and afternoon conditions. High-resolution vertical profiles of meteorological parameters obtained through balloon-borne GPS Sondes during the Winter phase of Integrated Campaign for Aerosols, gases and Radiation Budget (W-ICARB) formed the primary database for the present investigation. The study advocates usage of wind shear profiles in association with virtual potential temperature (θv) and specific humidity (q) profiles for determination of the mixed layer heights (MLH). The mean values of turbulent flow thickness (TFT) obtained from the vertical profiles of Bulk Richardson Number (RiB) and MLH magnitudes for the entire cruise did not show any appreciable variations for three classes. During the entire cruise period, the MLH varied in a range from 450 m to 1500 m with a mean of about 900 m, whereas the TFT variations were confined between 125 m and 1475 m with a mean of about 581 m. The statistical means of TFT and MLH were similar for nighttime profiles, whereas they showed significant differences in the morning and afternoon conditions. Spatio-temporal variability in the MLH showed good correlation with the surface-layer sensible heat flux which is one of the driving mechanisms in mixing processes.

  13. The effect of vertical velocity probability distribution shape on cloud activation of aerosols: off-line calculations

    NASA Astrophysics Data System (ADS)

    Tonttila, J.; Romakkaniemi, S.; Räisänen, P.; Kokkola, H.; Järvinen, H.

    2012-04-01

    Off-line calculations of cloud activation of aerosols using a probability density function (PDF) for vertical velocity (w) are performed. The focus is on the variation of the shape of the PDF using two functional formulations: the Normal distribution PDF and the Pearson type IV PDF. The Normal distribution provides a familiar example, as it has been widely used to approximate vertical velocity distributions in numerous applications, including climate models. Pearson type IV distribution provides an alternative that, to our knowledge, has not been employed before to describe the vertical velocity PDF. The advantage of the Pearson distribution is its versatility in representing skewed and more peaked distribution shapes compared to the Normal distribution, though this is obtained at the expense of increased mathematical complexity. The experiments are performed using a box model, in which the environmental conditions, including the aerosol size distribution (bi-modal) and chemical composition (ammonium-sulphate particles) are prescribed as constants. Measured size distributions comprising clean and polluted cases are used. Cloud activation of aerosols is calculated by integrating over the positive side of the PDF of w, which yields the mean number of activated particles (Nact). The mean, variance, and skewness of the PDFs along with the type of the PDF itself are altered in order to explore the effect of the PDF shape on the activation process. All experiments are repeated for three well-documented activation parameterizations: Lin & Leaitch, Abdul-Razzak & Ghan and Fountoukis & Nenes. The results show that for symmetric distributions of w (skewness = 0) there is a maximum difference of 10-15 % in Nact between the cases with w given by the Normal distribution, and the more peaked Pearson distribution. The largest differences are seen for the most polluted cases. Nact in clean cases will saturate rather quickly with respect to the maximum supersaturation and, hence

  14. Dominance of pollutant aerosols over an urban region and its impact on boundary layer temperature profile

    NASA Astrophysics Data System (ADS)

    Talukdar, Shamitaksha; Jana, Soumyajyoti; Maitra, Animesh

    2017-01-01

    Collocated measurements of aerosol optical depth (AOD) and black carbon at different wavelengths over Kolkata, an urban region in eastern India, have been used to calculate aerosol single-scattering albedo (SSA). The wavelength dependence of SSA and AOD has been presented to discriminate the aerosol types over this highly populated metropolitan area. The spectral pattern shows that SSA decreases with wavelength for most of the time in a year and corresponding Ångström coefficient is greater than unity. These optical properties indicate the dominance of fine-mode pollutant particles over the city. The temperature lapse rate profile within the surface boundary layer has been found to be significantly influenced by the heating effect of fine-mode pollutants, and consequently, the growth of the convective processes in the lower troposphere is notably affected. In addition, a back trajectory analysis has also been presented to indicate that transported air masses can have significant impact on spectral pattern of SSA.

  15. Improved parameterization for the vertical flux of dust aerosols emitted by an eroding soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The representation of the dust cycle in atmospheric circulation models hinges on an accurate parameterization of the vertical dust flux at emission. However, existing parameterizations of the vertical dust flux vary substantially in their scaling with wind friction velocity, require input parameters...

  16. Heterogeneous Vertical Hydraulic Conductivity in an Aquitard as Determined by Head Profiles and Pumping Tests

    NASA Astrophysics Data System (ADS)

    Hart, D. J.; Bradbury, K. R.; Cherry, J. A.; Gotkowitz, M. G.; Parker, B. L.

    2005-12-01

    The vertical hydraulic conductivity (Kv) of aquitards is one of the most important parameters in groundwater flow systems but presents special challenges for estimation. It determines the role of the aquitard in a flow system and is a measure of the protection given by the aquitard to underlying aquifers. The properties of aquitards vary vertically and estimates of Kv should reflect this heterogeneity. Vertical head profiles in aquitards show this heterogeneity, and are probably the most important data to be collected in aquitard studies. The heads rarely vary in a linear fashion with depth as would be expected in a homogeneous medium. Instead, most head loss is either at the top or the bottom of the identified aquitard, suggesting that some portion of the aquitard has a much lower Kv than the rest. While this portion is the most effective part of the aquitard, the rest of the aquitard can still present a barrier to flow. We determined the Kv profile of a six-meter thick shaley aquitard, the Eau Claire Formation, by measuring head profiles in, above, and below the aquitard before and during a pumping test. The head profile before the pumping test was measured using three systems: a FLUTeTM multi-level system with pressure transducers, a short interval straddle packer, and series of buried pressure transducers. All three measurements of heads gave similar profiles. The head decreased 1.5 meters in the upper five meters of the aquitard with most of the head drop, nine meters, occurring over the lower meter of the aquitard. The vertical component of gradient varied by a factor of 30. During the pumping test, the head profiles were measured with the FLUTe system and the buried pressure transducers. In general the two measurement systems agreed but significant differences occurred in the lowest conductivity part of the aquitard. The head profile measured by the FLUTe system showed variation similar to that in the rest of the aquitard while the head measured by the

  17. Vertical profiles and receptor modeling of volatile organic compounds over Southeastern Mexico City

    NASA Astrophysics Data System (ADS)

    Wöhrnschimmel, Henry; Márquez, Claudia; Mugica, Violeta; Stahel, Werner A.; Staehelin, Johannes; Cárdenas, Beatriz; Blanco, Salvador

    Tethered balloon flights were carried out over Southeastern Mexico City in April 2003, providing vertical profiles of ozone (0-1000 m above ground) and volatile organic compounds (VOCs, 0-200 m above ground). The objective of this study was to provide insight into the processes that drive ozone formation in Mexico City. In this paper, we discuss the atmospheric chemistry, emission sources and transport processes that influence the observed profiles. Characteristic ozone profiles were measured in the morning with the highest concentrations recorded in the residual layer. Maximum ozone concentrations, as high as 170 ppb, were measured at ground level in the afternoon. For the shape of VOC vertical profiles, no unique patterns were found. High concentrations were measured for propane, butane and toluene. Diurnal variations in VOC concentrations imply a strong effect of vertical dilution with an increasing mixing layer. Two different receptor models were used to relate observed VOC concentrations to emission sources. Results from a chemical mass balance (CMB) model suggest that the main contributors to total VOCs and the related ozone formation potential are gasoline vehicle exhaust and liquefied petroleum gas (LPG). A linear unmixing analysis reproduced satisfactorily the measured source profiles of the main sources. The relative source activities calculated by the CMB and the linear unmixing models coincide well for the LPG contribution; however, the vehicle exhaust contribution is underestimated and solvent emissions are overestimated by linear unmixing relative to the CMB model.

  18. Long-term impacts of aerosols on the vertical development of clouds and precipitation

    SciTech Connect

    Li, Zhanqing; Niu, F.; Fan, Jiwen; Liu, Yangang; Rosenfeld, Daniel; Ding, Yanni

    2011-12-01

    Aerosol has complex effects on clouds and precipitation that may augment or offset each other contingent upon a variety of variables. As a result, its long-term impact on climate is largely unknown. Using 10 years of the US Atmospheric Radiation Measurement (ARM) measurements, strong aerosol effects of climatologically significance are detected. With increasing total aerosol number concentration (condensation nucleus, CN) measured near the ground, both cloud top height and precipitation change systematically for mix-phase clouds of warm-base (cloud base <1km) and cold-top (above the freezing level), but not for pure liquid and ice clouds. Cloud thickness can increase systematically with the CN concentration by up to a factor of 2. The response of precipitation to CN depends on cloud liquid water path (LWP). As CN increases, rain occurs more frequently for high LWP but less frequently for low LWP. Such strong signals of aerosol long-term impact on cloud and precipitation have not been reported and have significant implications for climate change studies, especially concerning regional and global climate change induced by pollution.

  19. Simulation of Cloud-aerosol Lidar with Orthogonal Polarization (CALIOP) Attenuated Backscatter Profiles Using the Global Model of Aerosol Processes (GLOMAP)

    NASA Astrophysics Data System (ADS)

    Young, Stuart; Cope, Martin; Lee, Sunhee; Emmerson, Kathryn; Woodhouse, Matthew; Bellouin, Nicolas

    2016-06-01

    To permit the calculation of the radiative effects of atmospheric aerosols, we have linked our aerosol-chemical transport model (CTMGLOMAP) to a new radiation module (UKCARADAER). In order to help assess and improve the accuracy of the radiation code, in particular the height dependence of the predicted scattering, we have developed a module that simulates attenuated backscatter (ABS) profiles that would be measured by the satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) if it were to sample an atmosphere with the same aerosol loading as predicted by the CTM. Initial results of our comparisons of the predicted ABS profiles with actual CALIOP data are encouraging but some differences are noted, particularly in marine boundary layers where the scattering is currently under-predicted and in dust layers where it is often over-predicted. The sources of these differences are being investigated.

  20. Coarse-fine vertical scanning based optical profiler for structured surface measurement with large step height

    NASA Astrophysics Data System (ADS)

    Zheng, Yi; Liu, Xiaojun; Lei, Zili; Li, Qian; Yang, Xiao; Chen, Liangzhou; Lu, Wenlong

    2015-02-01

    White light interference (WLI) optical profiler had been used widely for structured surface measurement. To achieve high measuring accuracy, piezoelectric ceramic (PZT) was usually used as the vertical scanning unit, which was normally less than 100um and only for small range structured surface measurement. With the development of advanced manufacturing technology, precision structured surfaces with large step height were appearing. To satisfy the measurement requirements of this kind of precision structured surfaces, WLI optical profiler with large range had to be developed. In this paper, an optical profiler was proposed, in which a coarse-fine vertical scanning system was adopted to expand its measurement range to 10mm while its resolution still at nanometer level.

  1. CO2 vertical profile retrieval from ground-based IR atmospheric spectra

    NASA Astrophysics Data System (ADS)

    Khosravian, Kobra; Loehnert, Ulrich; Turner, David; Ebell, Kerstin

    2016-04-01

    CO2 vertical profile retrieval from ground-based IR atmospheric spectra In this study, we developed an algorithm for retrieving the CO2 vertical profile from atmospheric ground-based zenith spectra in the mid IR. Providing the CO2 profile from continuous (24h/day) ground-based spectra would be a great potential for studying the carbon cycle, the evaluation of satellite measurements or the assessment of numerical models, which forecast the near-surface CO2 flux. In order to retrieve the CO2 profile, we used observations of the Atmospheric Emitted Radiance Interferometer (AERI) that was installed at the JOYCE (Jülich ObservatorY for Cloud Evolution), Germany in 2012. AERI measures downwelling infrared radiances from 520 cm-1 (3.3 μm) to 3020 cm-1 (19 μm) with a spectral resolution of 1 cm-1 and a temporal resolution of 1 minute. In a first step, we performed sensitivity studies for finding the most-suited spectral bands with highest sensitivity to the mean column amount of CO2 volume mixing ratio (VMR). Then an algorithm, known as AERIoe (Turner and Löhnert 2014), was applied to retrieve the mean column amount of CO2 VMR using simulated radiances in clear sky cases. AERIoe is a variational retrieval algorithm to provide information on Temperature, humidity, trace gases and clouds. The simulated AERI radiances were generated by a line by line radiative transfer model (LBLRTM) using model temperature, humidity and CO2 profile. The retrieval results of mean column amount of CO2 VMR are in good agreement with the true ones. In addition to the mean column amount, we modified AERIoe to retrieve the CO2 vertical profile. First results reveal that there is more than 1 degree of freedom for CO2 profile. We will show results how the retrieval method is refined to optimally exploit the information on the CO2 profile contained in the AERI measurements.

  2. Development of a Climatology of Vertically Complete Wind Profiles from Doppler Radar Wind Profiler Systems

    NASA Technical Reports Server (NTRS)

    Barbre, Robert, Jr.

    2015-01-01

    Assessment of space vehicle loads and trajectories during design requires a large sample of wind profiles at the altitudes where winds affect the vehicle. Traditionally, this altitude region extends from near 8-14 km to address maximum dynamic pressure upon ascent into space, but some applications require knowledge of measured wind profiles at lower altitudes. Such applications include crew capsule pad abort and plume damage analyses. Two Doppler Radar Wind Profiler (DRWP) systems exist at the United States Air Force (USAF) Eastern Range and at the National Aeronautics and Space Administration's Kennedy Space Center. The 50-MHz DRWP provides wind profiles every 3-5 minutes from roughly 2.5-18.5 km, and five 915-MHz DRWPs provide wind profiles every 15 minutes from approximately 0.2-3.0 km. Archived wind profiles from all systems underwent rigorous quality control (QC) processes, and concurrent measurements from the QC'ed 50- and 915-MHz DRWP archives were spliced into individual profiles that extend from about 0.2-18.5 km. The archive contains combined profiles from April 2000 to December 2009, and thousands of profiles during each month are available for use by the launch vehicle community. This paper presents the details of the QC and splice methodology, as well as some attributes of the archive.

  3. Experimental study of vertical stress profiles of a confined granular bed under static and dynamic conditions.

    PubMed

    Mandato, S; Cuq, B; Ruiz, T

    2012-07-01

    In a wet agglomeration process inside a low shear mixer, the blade function is to induce i) homogenization of the liquid sprayed on the powder surface and ii) a stress field able to transfer the mechanical energy at the particle scale. In this work we study the mechanical state of a confined powder bed through the analysis of stress distributions (by force measurements) in a rectangular cell in two cases: for a classical model powder (i.e. glass beads) and a complex powder (i.e. wheat semolina). Two types of vertical stress profiles are obtained according to the type of measurements carried out in the powder bed, either locally (at different positions in the cell) or globally (at the entire base). The global vertical stress profile follows Janssen's model and the local vertical stress profile highlights a critical length, identified as the percolation threshold of the force network, and a shielding length near the bottom, which is similar to an influence length of the side walls. In the context of wet agglomeration, the results allow to consider the role of the characteristic lengths in the mixing bowl under vertical mechanical solicitation.

  4. Field evaluation of a direct push deployed sensor probe for vertical soil water content profiling

    NASA Astrophysics Data System (ADS)

    Vienken, Thomas; Reboulet, Ed; Leven, Carsten; Kreck, Manuel; Zschornack, Ludwig; Dietrich, Peter

    2015-04-01

    Reliable high-resolution information about vertical variations in soil water content, i.e. total porosity in the saturated zone, is essential for flow and transport predictions within the subsurface. However, porosity measurements are often associated with high efforts and high uncertainties, e.g. caused by soil disturbance during sampling or sensor installation procedures. In hydrogeological practice, commonly applied tools for the investigation of vertical soil water content distribution include gravimetric laboratory analyses of soil samples and neutron probe measurements. A yet less well established technique is the use of direct push-deployed sensor probes. Each of these methods is associated with inherent advantages and limitations due to their underlying measurement principles and operation modes. The presented study describes results of a joint field evaluation of the individual methods under different depositional and hydrogeological conditions with special focus on the performance on the direct push-deployed water content profiler. Therefore, direct push-profiling results from three different test sites are compared with results obtained from gravimetric analysis of soil cores and neutron probe measurements. In direct comparison, the applied direct push-based sensor probe proved to be a suitable alternative for vertical soil water content profiling to neutron probe technology, and, in addition, proved to be advantageous over gravimetric analysis in terms vertical resolution and time efficiency. Results of this study identify application-specific limitations of the methods and thereby highlight the need for careful data evaluation, even though neutron probe measurements and gravimetric analyses of soil samples are well established techniques (see Vienken et al. 2013). Reference: Vienken, T., Reboulet, E., Leven, C., Kreck, M., Zschornack, L., Dietrich, P., 2013. Field comparison of selected methods for vertical soil water content profiling. Journal of

  5. Convective cloud vertical velocity and mass-flux characteristics from radar wind profiler observations during GoAmazon2014/5: VERTICAL VELOCITY GOAMAZON2014/5

    SciTech Connect

    Giangrande, Scott E.; Toto, Tami; Jensen, Michael P.; Bartholomew, Mary Jane; Feng, Zhe; Protat, Alain; Williams, Christopher R.; Machado, Luiz

    2016-11-15

    A radar wind profiler data set collected during the 2 year Department of Energy Atmospheric Radiation Measurement Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign is used to estimate convective cloud vertical velocity, area fraction, and mass flux profiles. Vertical velocity observations are presented using cumulative frequency histograms and weighted mean profiles to provide insights in a manner suitable for global climate model scale comparisons (spatial domains from 20 km to 60 km). Convective profile sensitivity to changes in environmental conditions and seasonal regime controls is also considered. Aggregate and ensemble average vertical velocity, convective area fraction, and mass flux profiles, as well as magnitudes and relative profile behaviors, are found consistent with previous studies. Updrafts and downdrafts increase in magnitude with height to midlevels (6 to 10 km), with updraft area also increasing with height. Updraft mass flux profiles similarly increase with height, showing a peak in magnitude near 8 km. Downdrafts are observed to be most frequent below the freezing level, with downdraft area monotonically decreasing with height. Updraft and downdraft profile behaviors are further stratified according to environmental controls. These results indicate stronger vertical velocity profile behaviors under higher convective available potential energy and lower low-level moisture conditions. Sharp contrasts in convective area fraction and mass flux profiles are most pronounced when retrievals are segregated according to Amazonian wet and dry season conditions. During this deployment, wet season regimes favored higher domain mass flux profiles, attributed to more frequent convection that offsets weaker average convective cell vertical velocities.

  6. Characteristics of high resolution hydraulic head profiles and vertical gradients in fractured sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Meyer, Jessica R.; Parker, Beth L.; Cherry, John A.

    2014-09-01

    Accurately identifying the position of vertical hydraulic conductivity (Kv) contrasts is critical to the delineation of hydrogeologic units that serve as the basis for conceptual and numerical models of groundwater flow. High resolution head profiles have identified the position and thickness of Kv contrasts in clayey aquitards but this potential has not yet been thoroughly evaluated in sedimentary rocks. This paper describes an experiment in which head profiles with the highest, technically feasible resolution were obtained using Westbay® multilevel systems (MLS) installed in 15 cored holes at three sedimentary rock research sites with contrasting geologic and flow system conditions. MLSs were installed to maximum depths between 90 and 260 m with 2-5 monitoring zones per 10 m. Head profiles were measured over multiyear periods. The vertical component of hydraulic gradient (i.e., vertical gradient) was calculated for each pair of adjacent monitoring intervals in every MLS and then categorized based on its repeatability to facilitate interpretation of Kv contrasts and comparisons within boreholes, between boreholes at the same site, and between sites. The head and vertical gradient profiles from all three sites display systematic (i.e., simple, geometric) shapes defined by repeatable intervals of no to minimal vertical gradient, indicating relatively high Kv units, bounded by shorter depth intervals with large (up to -50 m/m) vertical gradients, indicating relatively low Kv units. The systematic nature of the profiles suggests flow in regular and interconnected fracture networks rather than dominated by a few key fractures with irregular orientations. The low Kv units were typically thin, with their positions and thicknesses not predicted by lithostratigraphy or detailed lithologic, geophysical, and horizontal hydraulic conductivity data. Hence, the position and thickness of units with contrasting Kv would not be evident if MLSs with the conventional number of

  7. Processed and interpreted US Geological Survey seismic reflection profile and vertical seismic profile, Powder River and Custer Counties, Montana

    SciTech Connect

    Balch, A.H.; Miller, J.J.; Lee, M.W.; Ryder, R.T.

    1981-01-01

    A US Geological Survey Vertical Seismic Profile (VSP) at the USGS Madison Limestone Test Well No. 2 was run on August 3-5, 1977. The seismic energy source was a single 60 in./sup 3/ Bolt LSS-3/sup 4/ land air gun, operated at 2000 psi. The recording interval was 25 feet from 7900 ft to 3800 ft; 40 ft from 3800 ft to 1500 ft; and 50 ft from 1500 ft to the surface. VSP data were digitally recorded, edited, composited, wavelet shaped, velocity filtered, time shifted, and vertically summed. A band pass filter was applied to match the surface recording frequency band. The surface reflection data were recorded October 15-19, 1978. The energy source was supplied by four Pelco vibrators spaced at 73 ft, with 16 sweeps over a 440 ft line segment. The geophone pattern was 36 detectors in a line 220 ft. long, 48 channels per source point with a five station gap across the source. Major reflecting events on the surface data, shown as continuous lines on the profile, were tied to the summed vertical seismic profile at the USGS Madison Limestone Test Well No. 2. For positive identification, these events were then tracked vertically on the VSP to their point of origin in the earth, and tied at that point to the lithologic log shown in the lower portion of this chart. Formation names corresponding to the lithologic log are also shown. Heavy lines on the lower figure generally correspond to principal geologic formation boundaries. The lighter lines show the general arrangement of lesser reflectors. This data aids petroleum and natural gas investigatons. (DP)

  8. Measuring vertical oxygen profiles in the hyporheic zone using planar optodes

    NASA Astrophysics Data System (ADS)

    Vieweg, M.; Fleckenstein, J. H.; Schmidt, C.

    2012-04-01

    On of the key parameters, controlling biogeochemical reactions in the hyporheic zone (HZ) is the distribution of oxygen. A reliable measurement of the vertical oxygen distribution is an important tool to understand the dynamic fluctuations of the aerobic zone within the HZ. With repeated measurements of continuous profiles, mixing of surface water and groundwater as well as the consumption of oxygen can be evaluated. We present a novel approach for the in situ measurements of vertical oxygen distribution in the riverbed using a planar optode. The luminescence based optode measurement enables a non invasive measurement without consumption of oxygen, no creation of preferential flow paths and only minimal disturbance of the flow field. Possible atmospheric contamination by pumping pore water into a vessel can be avoided and the readings are independent of flow velocity. A self manufactured planar optode is wrapped around an acrylic tube and installed in the riverbed. The measurement is performed by vertically moving a profiler-piston inside the acrylic tube. The piston holds a robust polymer optical fibre which emits a modulated light signal through the acrylic glass to the optode-foil and transmits the induced luminescence signal back to a commercially available trace oxygen meter. Temperature compensation is accomplished using a depth-oriented temperature probe nearby and processing the raw data within a Matlab script. Robust and unbiased oxygen profiles are obtained by averaging multiple consecutive measurements. To ensure a constant velocity of the profiler for replicating the exact measuring depths, an electric motor device is used. First results at our test site show a variable oxygen profile down to 40 cm depth which is strongly influenced by stream level and upwelling groundwater conditions. The measured oxygen profiles will serve as input parameter for a 3D solute transport and chemical reaction subsurface model of the HZ.

  9. Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

    NASA Astrophysics Data System (ADS)

    Barrera-Verdejo, María; Crewell, Susanne; Löhnert, Ulrich; Orlandi, Emiliano; Di Girolamo, Paolo

    2016-08-01

    Continuous monitoring of atmospheric humidity profiles is important for many applications, e.g., assessment of atmospheric stability and cloud formation. Nowadays there are a wide variety of ground-based sensors for atmospheric humidity profiling. Unfortunately there is no single instrument able to provide a measurement with complete vertical coverage, high vertical and temporal resolution and good performance under all weather conditions, simultaneously. For example, Raman lidar (RL) measurements can provide water vapor with a high vertical resolution, albeit with limited vertical coverage, due to sunlight contamination and the presence of clouds. Microwave radiometers (MWRs) receive water vapor information throughout the troposphere, though their vertical resolution is poor. In this work, we present an MWR and RL system synergy, which aims to overcome the specific sensor limitations. The retrieval algorithm combining these two instruments is an optimal estimation method (OEM), which allows for an uncertainty analysis of the retrieved profiles. The OEM combines measurements and a priori information, taking the uncertainty of both into account. The measurement vector consists of a set of MWR brightness temperatures and RL water vapor profiles. The method is applied to a 2-month field campaign around Jülich (Germany), focusing on clear sky periods. Different experiments are performed to analyze the improvements achieved via the synergy compared to the individual retrievals. When applying the combined retrieval, on average the theoretically determined absolute humidity uncertainty is reduced above the last usable lidar range by a factor of ˜ 2 with respect to the case where only RL measurements are used. The analysis in terms of degrees of freedom per signal reveal that most information is gained above the usable lidar range, especially important during daytime when the lidar vertical coverage is limited. The retrieved profiles are further evaluated using

  10. Continuous wavelet transform for micro-component profile measurement using vertical scanning interferometry

    NASA Astrophysics Data System (ADS)

    Li, M.; Quan, C.; Tay, C. J.

    2008-10-01

    White-light interferometric techniques have been widely used in three-dimensional (3D) profiling. This paper presents a new method based on vertical scanning interferometry (VSI) for the 3D profile measurement of a micro-component that contains sharp steps. The use of a white-light source in the system overcomes the phase ambiguity problem often encountered in monochromatic interferometry and also reduces speckle noises. A new algorithm based on the continuous wavelet transform (CWT) is used to retrieve the phase of an interferogram. The algorithm accurately determines local fringe peak and improves the vertical resolution of the measurement. The proposed method is highly resistant to noise and is able to achieve high accuracy. A micro-component (lamellar grating) fabricated by sacrificial etching technique is used as a test specimen to verify the proposed method. The measurement uncertainty of the experimental results is discussed.

  11. Observed changes in the vertical profile of stratopheric nitrous oxide at Thule, Greenland, February - March 1992

    NASA Technical Reports Server (NTRS)

    Emmons, Louisa K.; Reeves, John M.; Shindell, Drew T.; Dezafra, Robert L.

    1994-01-01

    Using a ground-based mm-wave spectrometer, we have observed stratospheric N2O over Thule, Greenland (76.3 N, 68.4 W) during late February and March, 1992. Vertical profiles of mixing ratio ranging from 16 to 50 km were recovered from molecular emission spectra. The profiles of early March show an abrupt increase in the lower-stratosphere N2O mixing ratio similar to the spring-to-summer change associated with the break up of the Antarctic polar vortex. This increase is correlated with changes in potential vorticity, air temperature, and ozone mixing ratio.

  12. The power of vertical geolocation of atmospheric profiles from GNSS radio occultation

    NASA Astrophysics Data System (ADS)

    Scherllin-Pirscher, Barbara; Steiner, Andrea K.; Kirchengast, Gottfried; Schwärz, Marc; Leroy, Stephen S.

    2017-02-01

    High-resolution measurements from Global Navigation Satellite System (GNSS) radio occultation (RO) provide atmospheric profiles with independent information on altitude and pressure. This unique property is of crucial advantage when analyzing atmospheric characteristics that require joint knowledge of altitude and pressure or other thermodynamic atmospheric variables. Here we introduce and demonstrate the utility of this independent information from RO and discuss the computation, uncertainty, and use of RO atmospheric profiles on isohypsic coordinates - mean sea level altitude and geopotential height - as well as on thermodynamic coordinates (pressure and potential temperature). Using geopotential height as vertical grid, we give information on errors of RO-derived temperature, pressure, and potential temperature profiles and provide an empirical error model which accounts for seasonal and latitudinal variations. The observational uncertainty of individual temperature/pressure/potential temperature profiles is about 0.7 K/0.15%/1.4 K in the tropopause region. It gradually increases into the stratosphere and decreases toward the lower troposphere. This decrease is due to the increasing influence of background information. The total climatological error of mean atmospheric fields is, in general, dominated by the systematic error component. We use sampling error-corrected climatological fields to demonstrate the power of having different and accurate vertical coordinates available. As examples we analyze characteristics of the location of the tropopause for geopotential height, pressure, and potential temperature coordinates as well as seasonal variations of the midlatitude jet stream core. This highlights the broad applicability of RO and the utility of its versatile vertical geolocation for investigating the vertical structure of the troposphere and stratosphere.

  13. Calcite: rates of dissolution in a vertical profile in the central pacific.

    PubMed

    Peterson, M N

    1966-12-23

    Rate of dissoluton of calcium carbonate (calcite) was determined for a vertical profile 5000 mizeters deep in the central Pacific by measuring the loss of weight of optical calcite spheres arrayed on a mooring. Waters of the Pacific are undersaturated in all but the upper several hundred meters. A sharp increase in the rate of dissolution occurs at a depth of about 3700 meters, which corresponds closely to the depth below which calcite hias been dissolved from the sediments.

  14. Using Airborne High Spectral Resolution Lidar Data to Evaluate Combined Active Plus Passive Retrievals of Aerosol Extinction Profiles

    NASA Technical Reports Server (NTRS)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Kittaka, C.; Vaughn, M. A.; Remer, L. A.

    2010-01-01

    We derive aerosol extinction profiles from airborne and space-based lidar backscatter signals by constraining the retrieval with column aerosol optical thickness (AOT), with no need to rely on assumptions about aerosol type or lidar ratio. The backscatter data were acquired by the NASA Langley Research Center airborne High Spectral Resolution Lidar (HSRL) and by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite. The HSRL also simultaneously measures aerosol extinction coefficients independently using the high spectral resolution lidar technique, thereby providing an ideal data set for evaluating the retrieval. We retrieve aerosol extinction profiles from both HSRL and CALIOP attenuated backscatter data constrained with HSRL, Moderate-Resolution Imaging Spectroradiometer (MODIS), and Multiangle Imaging Spectroradiometer column AOT. The resulting profiles are compared with the aerosol extinction measured by HSRL. Retrievals are limited to cases where the column aerosol thickness is greater than 0.2 over land and 0.15 over water. In the case of large AOT, the results using the Aqua MODIS constraint over water are poorer than Aqua MODIS over land or Terra MODIS. The poorer results relate to an apparent bias in Aqua MODIS AOT over water observed in August 2007. This apparent bias is still under investigation. Finally, aerosol extinction coefficients are derived from CALIPSO backscatter data using AOT from Aqua MODIS for 28 profiles over land and 9 over water. They agree with coincident measurements by the airborne HSRL to within +/-0.016/km +/- 20% for at least two-thirds of land points and within +/-0.028/km +/- 20% for at least two-thirds of ocean points.

  15. A general framework for modelling the vertical organic matter profile in mineral and organic soils

    NASA Astrophysics Data System (ADS)

    Braakhekke, Maarten; Ahrens, Bernhard

    2016-04-01

    The vertical distribution of soil organic matter (SOM) within the mineral soil and surface organic layer is an important property of terrestrial ecosystems that affects carbon and nutrient cycling and soil heat and moisture transport. The overwhelming majority of models of SOM dynamics are zero-dimensional, i.e. they do not resolve heterogeneity of SOM concentration along the vertical profile. In recent years, however, a number of new vertically explicit SOM models or vertically explicit versions of existing models have been published. These models describe SOM in units of concentration (mass per unit volume) by means of a reactive-transport model that includes diffusion and/or advection terms for SOM transport, and vertically resolves SOM inputs and factors that influence decomposition. An important assumption behind these models is that the volume of soil elements is constant over time, i.e. not affected by SOM dynamics. This assumption only holds if the SOM content is negligible compared to the mineral content. When this is not the case, SOM input or loss in a soil element may cause a change in volume of the element rather than a change in SOM concentration. Furthermore, these volume changes can cause vertical shifts of material relative to the surface. This generally causes material in an organic layer to gradually move downward, even in absence of mixing processes. Since the classical reactive-transport model of the SOM profile can only be applied to the mineral soil, the surface organic layer is usually either treated separately or not explicitly considered. We present a new and elegant framework that treats the surface organic layer and mineral soil as one continuous whole. It explicitly accounts for volume changes due to SOM dynamics and changes in bulk density. The vertical shifts resulting from these volume changes are included in an Eulerian representation as an additional advective transport flux. Our approach offers a more elegant and realistic

  16. Atmospheric dust charging, vertical profiles and optical properties measured in the Arabian Peninsula during the DREAME campaign

    NASA Astrophysics Data System (ADS)

    Ulanowski, Z.; Sabbah, I.; Harrison, R. G.; Nicoll, K. A.; Hirst, E.; Kaye, P. H.; Al-Abbadi, N.; Rogers, G.

    2010-05-01

    Polarimetric observations of atmospheric Saharan dust over the Canary Islands have provided strong evidence for the presence of vertically aligned particles. The alignment was thought to be due to the electric field present because of dust charging. It was concluded that the charging and consequent partial alignment could be a common feature of atmospheric mineral dust layers, influencing the optical properties of dust layers and possibly also dust transport (Atmos. Chem. Phys. 7, 6161, 2007). We show preliminary results from the DREAME campaign, aimed at investigating these phenomena. DREAME used simultaneous and collocated measurements from specially developed aerosol radiosondes, and ground-based sun photometers and electric field meters. The radiosondes provided vertical profiles of dust size distribution and electric charge density, in addition to standard meteorological parameters (Ulanowski et al. EGU 2010, AS3.16). The electric field was measured in Kuwait between late April and November 2009, and at Solar Village (Riyadh, Saudi Arabia) between May and June 2009. The measurements were supplemented by satellite retrievals of aerosol properties. Similar measurements but without electric field meters were carried out on Cape Verde Islands in August 2009 (Nicoll et al. EGU 2010, AS4.7). The electric field measured on the ground in Kuwait showed strong variability, particularly in the presence of atmospheric dust, when polarity reversals from the normal positive potential gradient (PG) clear-sky pattern were frequently observed. In the absence of clouds the negative PG excursions were often down to -800 V/m and reached -1300 V/m. The PG was strongly correlated with the aerosol optical thickness (AOT) from the sun photometer: the correlation coefficient was about -0.51 at visible and near infra-red wavelengths and a few percent less in the UV. Slightly lower correlation was present for satellite AOT: -0.4 for MODIS AOT at 550 nm, and -0.3 for OMI AOT at 483.5 nm

  17. On deriving the accurate aerosol extinction profiles in the troposphere and lower stratosphere using the range dependent scattering ratio

    NASA Astrophysics Data System (ADS)

    Satyanarayana, M. V.; Radhakrishnan, S. R.; Mahadevanpillai, V. P.; Krishnakumar, V.

    2008-12-01

    Lidar has proven to be an effective instrument for obtaining high resolution profiles of atmospheric aerosols. Deriving the optical properties of aerosols from the experimentally obtained lidar data is one of the most interesting and challenging task for the atmospheric scientists. A few methods had been developed so far, to obtain the quantitative profiles of extinction and backscattering coefficient of aerosols from the pulsed backscattering lidar measurements. Most of the existing inversion methods assume a range independent value for the scattering ratio for inverting the lidar signal even though it is known that the scattering ratio depends on the nature of aerosols and as such range dependent. We used a modified Klett's method for the inversion of lidar signal that uses range dependent scattering ratio (s) for the characterization of atmospheric aerosols. This method provides the constants k and s for all the altitude regions of the atmosphere and leads to derive the aerosol extinction profile for the lidar data. In this paper we made a study on the errors involved in the extinction profiles derived using the range dependent scattering ratio and discuss the approach in this regard to obtain the accurate extinction profiles.

  18. Complex vertical layering and mixing of aerosols over the eastern Mediterranean: active and passive remote sensing at the Cyprus University of Technology

    NASA Astrophysics Data System (ADS)

    Mamouri, R.-E.; Nisantzi, A.; Hadjimitsis, D. G.; Ansmann, A.; Schwarz, A.; Basart, S.; Baldasano, J. M.

    2013-08-01

    Aerosols 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 aerosols originating from European, Asian and African continents. Complex vertical aerosol distributions are frequently detected over Cyprus by means of active remote sensing. Observations of such complex aerosol layering and comparison of the measurements with aerosol products of regional and global atmospheric transport models are required to improve our understanding of life cycles of aerosol 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 layer 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 aerosol characteristics in terms of particle optical and microphysical properties, separately for the spherical particle fraction as well as for the non-spherical aerosol mode.

  19. Studying Vertical Microbiome Transmission from Mothers to Infants by Strain-Level Metagenomic Profiling

    PubMed Central

    Manara, Serena; Truong, Duy Tin; Armanini, Federica; Ferretti, Pamela; Gorfer, Valentina; Pedrotti, Anna

    2017-01-01

    ABSTRACT The gut microbiome becomes shaped in the first days of life and continues to increase its diversity during the first months. Links between the configuration of the infant gut microbiome and infant health are being shown, but a comprehensive strain-level assessment of microbes vertically transmitted from mother to infant is still missing. We collected fecal and breast milk samples from multiple mother-infant pairs during the first year of life and applied shotgun metagenomic sequencing followed by computational strain-level profiling. We observed that several specific strains, including those of Bifidobacterium bifidum, Coprococcus comes, and Ruminococcus bromii, were present in samples from the same mother-infant pair, while being clearly distinct from those carried by other pairs, which is indicative of vertical transmission. We further applied metatranscriptomics to study the in vivo gene expression of vertically transmitted microbes and found that transmitted strains of Bacteroides and Bifidobacterium species were transcriptionally active in the guts of both adult and infant. By combining longitudinal microbiome sampling and newly developed computational tools for strain-level microbiome analysis, we demonstrated that it is possible to track the vertical transmission of microbial strains from mother to infants and to characterize their transcriptional activity. Our work provides the foundation for larger-scale surveys to identify the routes of vertical microbial transmission and its influence on postinfancy microbiome development. IMPORTANCE Early infant exposure is important in the acquisition and ultimate development of a healthy infant microbiome. There is increasing support for the idea that the maternal microbial reservoir is a key route of microbial transmission, and yet much is inferred from the observation of shared species in mother and infant. The presence of common species, per se, does not necessarily equate to vertical transmission, as

  20. Vertical distribution of the different types of aerosols in the stratosphere: Detection of solid particles and analysis of their spatial variability

    NASA Astrophysics Data System (ADS)

    Renard, Jean-Baptiste; Brogniez, Colette; Berthet, GwenaëL.; Bourgeois, Quentin; Gaubicher, Bertrand; Chartier, Michel; Balois, Jean-Yves; Verwaerde, Christian; Auriol, FréDéRique; Francois, Philippe; Daugeron, Daniel; Engrand, CéCile

    2008-11-01

    all latitudes, could be injected into the lower stratosphere by the pyroconvective effect and can then reach the middle stratosphere perhaps owing to the gravitophotophoresis effect as was theoretically proposed. In the lower unperturbed stratosphere, liquid sulfate aerosols dominate, although soot particles are still present. Local horizontal and vertical enhancements of solid aerosols have sometimes been detected, although their origin is not yet determined. The presence of these solid particles can strongly bias the interpretation of in situ and remote sensing measurements when only the presence of liquid aerosols is assumed. Therefore, a new strategy of measurement will be necessary in the future to better characterize the stratospheric aerosol content free of volcanic particles.

  1. Vertically-resolved profiles of mass concentrations and particle backscatter coefficients of Asian dust plumes derived from lidar observations of silicon dioxide.

    PubMed

    Noh, Youngmin; Müller, Detlef; Shin, Sung-Kyun; Shin, Dongho; Kim, Young J

    2016-01-01

    This study presents a method to retrieve vertically-resolved profiles of dust mass concentrations by analyzing Raman lidar signals of silicon dioxide (quartz) at 546nm. The observed particle plumes consisted of mixtures of East Asian dust with anthropogenic pollution. Our method for the first time allows for extracting the contribution of the aerosol component "pure dust" contained in the aerosol type "polluted dust". We also propose a method that uses OPAC (Optical Properties of Aerosols and Clouds) and the mass concentrations profiles of dust in order to derive profiles of backscatter coefficients of pure dust in mixed dust/pollution plumes. The mass concentration of silicon dioxide (quartz) in the atmosphere can be estimated from the backscatter coefficient of quartz. The mass concentration of dust is estimated by the weight percentage (38-77%) of mineral quartz in Asian dust. The retrieved dust mass concentrations are classified into water soluble, nucleation, accumulation, mineral-transported and coarse mode according to OPAC. The mass mixing ratio of 0.018, 0.033, 0.747, 0.130 and 0.072, respectively, is used. Dust extinction coefficients at 550nm were calculated by using OPAC and prescribed number concentrations for each of the 5 components. Dust backscatter coefficients were calculated from the dust extinction coefficients on the basis of a lidar ratio of 45±3sr at 532nm. We present results of quartz-Raman measurements carried out on the campus of the Gwangju Institute of Science and Technology (35.10°N, 126.53°E) on 15, 16, and 21 March 2010.

  2. LASE measurements of aerosols and water vapor during TARFOX

    NASA Technical Reports Server (NTRS)

    Ferrare, Richard A.; Ismail, Syed; Browell, Edward V.; Brackett, Vincent G.; Kooi, Susan A.; Clayton, Marian B.; Melfi, Harvey; Whiteman, David N.; Schwenner, Geary; Evans, Keith D.; Hobbs, Peter V.; Veefkind, J. Pepijn; Russell, Philip B.; Livingston, John M.; Hignett, Philip; Holben, Brent N.; Remer, Lorraine A.

    1998-01-01

    The TARFOX (Tropospheric Aerosol Radiative Forcing Observational Experiment) intensive field campaign was designed to reduce uncertainties in estimates of the effects of anthropogenic aerosols on climate by measuring direct radiative effects and the optical, physical, and chemical properties of aerosols [1]. TARFOX was conducted off the East Coast of the United States between July 10-31, 1996. Ground, aircraft, and satellite-based sensors measured the sensitivity of radiative fields at various atmospheric levels to aerosol optical properties (i.e., optical thickness, phase function, single-scattering albedo) and to the vertical profile of aerosols. The LASE (Lidar Atmospheric Sensing Experiment) instrument, which was flown on the NASA ER-2 aircraft, measured vertical profiles of total scattering ratio and water vapor during a series of 9 flights. These profiles were used in real-time to help direct the other aircraft to the appropriate altitudes for intensive sampling of aerosol layers. We have subsequently used the LASE aerosol data to derive aerosol backscattering and extinction profiles. Using these aerosol extinction profiles, we derived estimates of aerosol optical thickness (AOT) and compared these with measurements of AOT from both ground and airborne sun photometers and derived from the ATSR-2 (Along Track and Scanning Radiometer 2) sensor on ERS-2 (European Remote Sensing Satellite-2). We also used the water vapor mixing ratio profiles measured simultaneously by LASE to derive precipitable water vapor and compare these to ground based measurements.

  3. Vertical distribution of optical parameters of aerosol, evaluation of rain rate and rain drop size by using the pal system, at guwahati

    NASA Astrophysics Data System (ADS)

    Devi, M.; Barbara, A. K.; Baishya, R.; Takeuchi, N.

    The paper gives in brief, the features of a Portable Automated Lidar (PAL) set up, fabricated and operated at Guwahati (260N and 920 E) a subtropical station, for monitoring of aerosol, cloud and precipitation features and then describes the method adopted for profiling of aerosol and determination of rain rate as well as drop sizes with coupled observation from distrometer and radiosonde. The PAL generates 532 nm laser pulses of 10 ns duration of high repetition rate of 1-2 kHz. The backscattered signals from atmospheric constituents collected by a telescope of diameter 20 cm., and amplified with a Photo Multiplier Tube (PMT), are then processed in Lab View environment by a software for, extracting aerosol and cloud features. For checking and correcting the alignment affected by temperature, provisions are also introduced for easy adjustment of horizontal and vertical axes. In this approach we have evaluated system constant C, from the lidar backscattered signal itself, for an assumed lidar ratio as a first approach, and with extinction co-efficient determined experimentally. Here, the lidar is put for probing the atmosphere horizontally, when we may assume the atmosphere to be homogeneous along the FOV of the lidar. However, as horizontal in-homogeneity of the atmosphere cannot be ruled out, the paper illustrates the type of profiles adopted for such analysis and the lidar being situated in a semi rural area, a methodical screening approach adopted for selection of echograms free from shoot and fossil burning by product is described. Once the backscatter power with distance is known from the selected lidar outputs, σ is evaluated from the slope of the profile associating ``ratio of backscatter power to transmitter power'' with distance r. The methods taken up for realization of β value and then determination of C are elaborated in the paper. The lidar ratio S, is assumed from reported results as a first reference value. This parameter S is then checked for its

  4. First characterization and validation of FORLI-HNO3 vertical profiles retrieved from IASI/Metop

    NASA Astrophysics Data System (ADS)

    Ronsmans, Gaétane; Langerock, Bavo; Wespes, Catherine; Hannigan, James W.; Hase, Frank; Kerzenmacher, Tobias; Mahieu, Emmanuel; Schneider, Matthias; Smale, Dan; Hurtmans, Daniel; De Mazière, Martine; Clerbaux, Cathy; Coheur, Pierre-François

    2016-09-01

    Knowing the spatial and seasonal distributions of nitric acid (HNO3) around the globe is of great interest and allows us to comprehend the processes regulating stratospheric ozone, especially in the polar regions. Due to its unprecedented spatial and temporal sampling, the nadir-viewing Infrared Atmospheric Sounding Interferometer (IASI) is capable of sounding the atmosphere twice a day globally, with good spectral resolution and low noise. With the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, we are retrieving, in near real time, columns as well as vertical profiles of several atmospheric species, among which is HNO3. We present in this paper the first characterization of the FORLI-HNO3 profile products, in terms of vertical sensitivity and error budgets. We show that the sensitivity of IASI to HNO3 is highest in the lower stratosphere (10-20 km), where the largest amounts of HNO3 are found, but that the vertical sensitivity of IASI only allows one level of information on the profile (degrees of freedom for signal, DOFS; ˜ 1). The sensitivity near the surface is negligible in most cases, and for this reason, a partial column (5-35 km) is used for the analyses. Both vertical profiles and partial columns are compared to FTIR ground-based measurements from the Network for the Detection of Atmospheric Composition Change (NDACC) to characterize the accuracy and precision of the FORLI-HNO3 product. The profile validation is conducted through the smoothing of the raw FTIR profiles by the IASI averaging kernels and gives good results, with a slight overestimation of IASI measurements in the upper troposphere/lower stratosphere (UTLS) at the six chosen stations (Thule, Kiruna, Jungfraujoch, Izaña, Lauder and Arrival Heights). The validation of the partial columns (5-35 km) is also conclusive with a mean correlation of 0.93 between IASI and the FTIR measurements. An initial survey of the HNO3 spatial and seasonal variabilities obtained from IASI

  5. Characteristics of ozone vertical profile observed in the boundary layer around Beijing in autumn.

    PubMed

    Ma, Zhiqiang; Zhang, Xiaoling; Xu, Jing; Zhao, Xiujuan; Meng, Wei

    2011-01-01

    In the autumn of 2008, the vertical profiles of ozone and meteorological parameters in the low troposphere (0-1000 m) were observed at two sites around Beijing, specifically urban Nanjiao and rural Shangdianzi. At night and early morning, the lower troposphere divided into two stratified layers due to temperature inversion. Ozone in the lower layer showed a large gradient due to the titration of NO. Air flow from the southwest brought ozone-rich air to Beijing, and the ozone profiles were marked by a continuous increase in the residual layer at night. The accumulated ozone in the upper layer played an important role in the next day's surface peak ozone concentration, and caused a rapid increase in surface ozone in the morning. Wind direction shear and wind speed shear exhibited different influences on ozone profiles and resulted in different surface ozone concentrations in Beijing.

  6. Determining long-term effective groundwater recharge by analyzing vertical soil temperature profiles at meteorological stations

    NASA Astrophysics Data System (ADS)

    Cheviron, Bruno; Guérin, Roger; Tabbagh, Alain; Bendjoudi, Hocine

    2005-09-01

    Vertical water seepage in soils results in convective heat transport that modifies the temperature profiles and their variations with time; consequently, there is a relationship between temperature profile variations with time and the vertical Darcy velocity associated with the seepage. Considering the annual sinusoidal time variation of the temperature at the soil surface, it can be shown that convective heat transport has a significant effect on the amplitude damping with depth and a negligible effect on the phase lag with depth of the temperature time signal. Standard meteorological stations constitute a relatively dense network, and we show that their routinely collected data can be used to determine an average value of the vertical Darcy velocity, uz, representing the effective annual recharge over long time periods (several years). A new procedure for determining uz from these temperature records is presented. First, the layering of the medium is determined by an electrical sounding. Then the thermal properties of each layer are inferred from the phase lag with depth. Finally, uz is calculated from the amplitude damping. After having tested this approach with synthetic data, we used the 1984-2001 Abbeville (Somme, France) data to determine the average recharge over six 3-year periods. The results are in good agreement with classical meteorological recharge estimates and show a significant increase in the recharge during the last 3-year period, consistent with the observed phreatic 2001 flood event. Specific temperature measurements at appropriate depths and time steps could drastically improve the sensitivity of the method.

  7. Indoor and outdoor measurements of vertical concentration profiles of airborne particulate matter.

    PubMed

    Micallef, A; Deuchar, C N; Colls, J J

    1998-05-04

    Vertical concentration profiles of various particle size ranges of airborne particulate matter were measured from ground level up to 3 m, in outdoor and indoor environments. Indoor measurements were carried out in an electronics workshop, while two outdoor environments were chosen: a street canyon cutting across a town and an open field situated in a semi-rural environment. The novel measurement technique employed in this experimental work, which can also be used to determine vertical concentration gradients of pollutants other than airborne particles in different environments, is given particular attention. Analyses of the collected data for the environments considered are presented and some conclusions and plausible explanations of the profiles are discussed. The workshop and street canyon environments exhibited larger concentrations and vertical concentration gradients as compared to the sports field. This indicates that people breathing at different heights are subjected to different concentrations of airborne particulate matter, which has implications for sitting air pollution monitors intended for protection of public health and estimation of human exposure.

  8. Vertical distribution of optical and microphysical properties of smog aerosols measured by multi-wavelength polarization lidar in Xi'an, China

    NASA Astrophysics Data System (ADS)

    Di, Huige; Hua, Hangbo; Cui, Yan; Hua, Dengxin; He, Tingyao; Wang, Yufeng; Yan, Qing

    2017-02-01

    In this study, a multi-wavelength polarization lidar was developed at the Lidar Center for Atmosphere Remote Sensing, in Xi'an, China to study the vertical distribution of the optical and microphysical properties of smog aerosols. To better understand smog, two events with different haze conditions observed in January 2015 were analyzed in detail. Using these data, we performed a vertical characterization of smog evolution using the lidar range-squared-corrected signal and the aerosol depolarization ratio. Using inversion with regularization, we retrieved the vertical distribution of aerosol microphysical properties, including volume size distribution, volume concentration, number concentration and effective radius. We also used the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model to analyze aerosol sources during the two episodes. Our results show that the most polluted area in the lower troposphere during smog episodes is located below a height of 1 km above the ground level; under more severe smog conditions, it can be below 0.5 km. In the case of severe smog, we found a large number of spherical and fine particles concentrated in the very low troposphere, even below 0.5 km. Surprisingly, a dust layer with a slight depolarization ratio was observed above the smog layer.

  9. Comparison of glyoxal, BrO, and IO vertical profiles derived from both ground-based and airborne MAX-DOAS measurements

    NASA Astrophysics Data System (ADS)

    Coburn, Sean; Volkamer, Rainer; Baidar, Sunil; Dix, Barbara; Koenig, Theodore; Ortega, Ivan; Sinreich, Roman; van Roozendael, Michel; Hendrick, Francois; Kinnison, Doug

    2015-04-01

    The information content of ground-based MAX-DOAS retrievals is assessed by collocated aircraft measurements for a ship MAX-DOAS setup over the Eastern tropical Pacific Ocean (TORERO RF17), and a mountain-top MAX-DOAS setup at Mauna Loa Observatory, Hawaii (CONTRAST RF17). During both case studies the CU airborne MAX-DOAS (AMAX-DOAS) instrument aboard the NSF/NCAR GV aircraft measured profiles of glyoxal, BrO, and IO with 12-20 degrees of freedom and up to 500 m vertical resolution. The TORERO field campaign took place in 2012, while CONTRAST in 2014; both campaigns covered the months of January and February. Additional measurements aboard the aircraft helped to provide information/validation of the AMAX-DOAS derived profiles, such as in-situ water vapor from the Vertical-Cavity Surface-Emitting Laser hygrometer (VCSEL), in-situ hydrocarbon measurements from the Trace Organic Gas Analyzer (TOGA), and aerosol information constrained by the Ultra High Sensitivity Aerosol Spectrometer (UHSAS). The AMAX-DOAS profiles are compared with ground-based MAX-DOAS inversions. The latter explores the effect of using either the measured differential slant column density (dSCD) or SCD as input to the optimal estimation inversion, where SCD = dSCD + SCD_ref. SCD_ref is the residual column amount of the trace gas contained within the reference spectrum. For the AMAX-DOAS data, the values of SCD_ref were actively minimized, while SCD_ref is usually unknown for ground-based MAX-DOAS retrievals. In absence of independent measurements to constrain SCD_ref, the current state-of-the-art with ground-based MAX-DOAS applications is to use dSCDs as input to the inversion. Here we assess the effect of uncertain SCD_ref for ground-based MAX-DOAS profiles in form of a sensitivity study. Additionally for the ground-based data, different methods are compared for the determination of SCD_ref: 1) the collocated aircraft profiles described above present the opportunity to forward calculate the SCD

  10. Variability of the vertical profile of wind speed: characterization at various time scales and analytical approximation

    NASA Astrophysics Data System (ADS)

    Jourdier, Bénédicte; Plougonven, Riwal; Drobinski, Philippe; Dupont, Jean-Charles

    2014-05-01

    Wind measurements are key for the wind resource assessment. But as wind turbines get higher, wind measurement masts are often lower than the future wind turbine hub height. Therefore one of the first steps in the energy yield assessment is the vertical extrapolation of wind measurements. Such extrapolation is often done by approximating the vertical profile of wind speed with an analytical expression: either a logarithmic law which has a theoretical basis in Monin-Obukhov similarity theory; or a power law which is empirical. The present study analyzes the variability of the wind profile and how this variability affects the results of the vertical extrapolation methods. The study is conducted with data from the SIRTA observatory, 20km south of Paris (France). A large set of instrumentation is available, including sonic anemometers at 10 and 30 meters, a LIDAR measuring wind speeds from 40 to 200 meters and a SODAR measuring wind speeds starting from 100m up to 1km. The comparison between the instruments enables to characterize the measurements uncertainties. The observations show that close to the ground the wind is stronger during daytime and weaker at night while higher, around 150 m, the wind is weaker during daytime and stronger at night. Indeed the wind shear has a pronounced diurnal cycle. The vertical extrapolation methods currently used in the industry do not usually take into account the strong variability of the wind profile. The often fit the parameters of the extrapolation law, not on each time step, but on time-averaged profiles. The averaging period may be the whole measurement period or some part of it: there may be one constant parameter computed on the wind profile that was averaged on the whole year of measures, or the year of measures may be divided into a small number of cases (for example into night or daytime data, or into 4 seasons) and the parameter is adjusted for each case. The study analyzes thoroughly the errors generated by both

  11. Vertical Structure and Optical Properties of Titans Aerosols from Radiance Measurements Made Inside and Outside the Atmosphere

    NASA Technical Reports Server (NTRS)

    Doose, Lyn R.; Karkoschka, Erich; Tomasko, Martin G.; Anderson, Carrie M.

    2017-01-01

    Prompted by the detection of stratospheric cloud layers by Cassini's Composite Infrared Spectrometer (CIRS; see Anderson, C.M., Samuelson, R.E. [2011]. Icarus 212, 762-778), we have re-examined the observations made by the Descent Imager/Spectral Radiometer (DISR) in the atmosphere of Titan together with two constraints from measurements made outside the atmosphere. No evidence of thin layers (<1 km) in the DISR image data sets is seen beyond the three previously reported layers at 21 km, 11 km, and 7 km by Karkoschka and Tomasko (Karkoschka, E., Tomasko, M.G. [2009]. Icarus 199, 442-448). On the other hand, there is evidence of a thicker layer centered at about 55 km. A rise in radiance gradients in the Downward-Looking Visible Spectrometer (DLVS) data below 55 km indicates an increase in the volume extinction coefficient near this altitude. To fit the geometric albedo measured from outside the atmosphere the decrease in the single scattering albedo of Titan's aerosols at high altitudes, noted in earlier studies of DISR data, must continue to much higher altitudes. The altitude of Titan's limb as a function of wavelength requires that the scale height of the aerosols decrease with altitude from the 65 km value seen in the DISR observations below 140 km to the 45 km value at higher altitudes. We compared the variation of radiance with nadir angle observed in the DISR images to improve our aerosol model. Our new aerosol model fits the altitude and wavelength variations of the observations at small and intermediate nadir angles but not for large nadir angles, indicating an effect that is not reproduced by our radiative transfer model. The volume extinction profiles are modeled by continuous functions except near the enhancement level near 55 km altitude. The wavelength dependence of the extinction optical depth is similar to earlier results at wavelengths from 500 to 700 nm, but is smaller at shorter wavelengths and larger toward longer wavelengths. A Hapke

  12. Investigation of blast-induced fracture in rock mass using reversed vertical seismic profiling

    NASA Astrophysics Data System (ADS)

    Zou, D. H.; Wu, Y. K.

    2001-10-01

    The rock mass on quarry and pit wall surfaces is usually fractured during production blasting. Quantitative investigations of the fractured zones are needed for stabilization of the rock walls. In this study, the principle of reversed vertical seismic profiling (RVSP) was applied. A set of seismic geophones were arranged on the horizontal bench surface and seismic signals were generated along the vertical rock wall using a free-swinging hammer. The travel times of seismic rays were recorded and the P-wave velocities of the rock mass were analyzed using the Simultaneous Iterative Reconstruction Technique (SIRT). A series of site tests have been carried out on the rock walls at a granite quarry that are characterized by fractures. The fracture depth at various locations on the wall surface is thereby determined. The results indicate that RVSP provides an easy and reliable method to quantitatively evaluate the blasting-induced fractures in the rock mass.

  13. Long-Term Mean Vertical Motion over the Tropical Pacific: Wind-Profiling Doppler Radar Measurements

    NASA Astrophysics Data System (ADS)

    Gage, K. S.; McAfee, J. R.; Carter, D. A.; Ecklund, W. L.; Riddle, A. C.; Reid, G. C.; Balsley, B. B.

    1991-12-01

    Measurement from Christmas Island (2^circN, 157^circW) of long-term mean vertical motions in the tropical atmosphere using very-high-frequency wind-profiling Doppler radar show that there is a transition from downward motion in the free troposphere to upward motion in the upper troposphere and lower stratosphere. The observations in the free troposphere are consistent with a balance between adiabatic and diabatic heating and cooling rates in a clear atmosphere. Comparison of the results at Christmas Island during El Nino and non-El Nino conditions with earlier results obtained for stratiform rain conditions over Pohnpei, Federated States of Micronesia, show that cirrus clouds in the vicinity of the tropopause likely play an important role in determining the sense and magnitude of vertical motions in this region. These results have implications for the exchange of mass between the troposphere and stratosphere over the tropics.

  14. Vertical distribution of organochlorine pesticides in humus along Alpine altitudinal profiles in relation to ambiental parameters.

    PubMed

    Kirchner, M; Faus-Kessler, T; Jakobi, G; Levy, W; Henkelmann, B; Bernhöft, S; Kotalik, J; Zsolnay, A; Bassan, R; Belis, C; Kräuchi, N; Moche, W; Simoncic, P; Uhl, M; Weiss, P; Schramm, K-W

    2009-12-01

    In forest soils along vertical profiles located in different parts of the Alps, concentrations of persistent organic pollutants (POPs), namely organochlorine pesticides (OCPs) like dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCH), heptachlor, aldrin, dieldrin and mirex, were measured. Though local characteristics of the sites are influenced by numerous factors like orographic and meteorological parameters, forest stand characteristics and humus parameters, we ascertained a marked vertical increase of concentrations of some organochlorine compounds in the soil. On the basis of climatological values of each site, we found that the contamination increase with altitude can be ascribed to a certain 'cold condensation effect'. In addition, the perennial atmospheric deposition of POPs is controlled by precipitation. Other key parameters explaining the accumulation of POPs are the soil organic carbon stocks, the turnover times, the re-volatilisation and degradation processes, which vary with altitude.

  15. Vertical profiles of heating derived from IR-based precipitation estimates during FGGE SOP-1

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin R.; Vincent, Dayton G.

    1988-01-01

    This paper examines a technique for retrieving from geostationary IR data the vertical profiles of heating and cooling due to moist diabatic processes. First, GOES IR imagery is used to estimate precipitation fields which are independent of fields inferred from residuals in heat budget analysis based on the FGGE level III-b data. Vertical distributions of the associated heating are then obtained using thermodynamic data from the level III-b analysis, one-dimensional cloud models, and the satellite-estimated precipitation. The technique was applied to infer heating in the South Pacific convergence zone during a portion of FGEE SOP-1, and the results were compared with heat-budget calculations made using the ECMWF analyses.

  16. A comparison of vertical velocity variance measurements from wind profiling radars and sonic anemometers

    NASA Astrophysics Data System (ADS)

    McCaffrey, Katherine; Bianco, Laura; Johnston, Paul; Wilczak, James M.

    2017-03-01

    Observations of turbulence in the planetary boundary layer are critical for developing and evaluating boundary layer parameterizations in mesoscale numerical weather prediction models. These observations, however, are expensive and rarely profile the entire boundary layer. Using optimized configurations for 449 and 915 MHz wind profiling radars during the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA), improvements have been made to the historical methods of measuring vertical velocity variance through the time series of vertical velocity, as well as the Doppler spectral width. Using six heights of sonic anemometers mounted on a 300 m tower, correlations of up to R2 = 0. 74 are seen in measurements of the large-scale variances from the radar time series and R2 = 0. 79 in measurements of small-scale variance from radar spectral widths. The total variance, measured as the sum of the small and large scales, agrees well with sonic anemometers, with R2 = 0. 79. Correlation is higher in daytime convective boundary layers than nighttime stable conditions when turbulence levels are smaller. With the good agreement with the in situ measurements, highly resolved profiles up to 2 km can be accurately observed from the 449 MHz radar and 1 km from the 915 MHz radar. This optimized configuration will provide unique observations for the verification and improvement to boundary layer parameterizations in mesoscale models.

  17. Turbulence velocity profiling for high sensitivity and vertical-resolution atmospheric characterization with Stereo-SCIDAR

    NASA Astrophysics Data System (ADS)

    Osborn, J.; Butterley, T.; Townson, M. J.; Reeves, A. P.; Morris, T. J.; Wilson, R. W.

    2017-02-01

    As telescopes become larger, into the era of ˜40 m Extremely Large Telescopes, the high-resolution vertical profile of the optical turbulence strength is critical for the validation, optimization and operation of optical systems. The velocity of atmospheric optical turbulence is an important parameter for several applications including astronomical adaptive optics systems. Here, we compare the vertical profile of the velocity of the atmospheric wind above La Palma by means of a comparison of Stereo-SCIntillation Detection And Ranging (Stereo-SCIDAR) with the Global Forecast System models and nearby balloon-borne radiosondes. We use these data to validate the automated optical turbulence velocity identification from the Stereo-SCIDAR instrument mounted on the 2.5 m Isaac Newton Telescope, La Palma. By comparing these data we infer that the turbulence velocity and the wind velocity are consistent and that the automated turbulence velocity identification of the Stereo-SCIDAR is precise. The turbulence velocities can be used to increase the sensitivity of the turbulence strength profiles, as weaker turbulence that may be misinterpreted as noise can be detected with a velocity vector. The turbulence velocities can also be used to increase the altitude resolution of a detected layer, as the altitude of the velocity vectors can be identified to a greater precision than the native resolution of the system. We also show examples of complex velocity structure within a turbulent layer caused by wind shear at the interface of atmospheric zones.

  18. Vertical Tracer Concentration Profiles Measured During the Joint Urban 2003 Dispersion Study

    SciTech Connect

    Flaherty, Julia E.; Lamb, Brian K.; Allwine, K Jerry; Allwine, Eugene J.

    2007-12-01

    An atmospheric tracer dispersion study known as Joint Urban 2003 was conducted in Oklahoma City, Oklahoma during the summer of 2003. As part of this field program, vertical concentration profiles were measured at approximately 1 km from downtown tracer gas release locations. These profiles indicated that the urban landscape was very effective in mixing the plume vertically. The height of the plume centerline (as determined by the maximum concentration over the depth of the measurements) for any specific 30 min period varied over the 65 m measurement range. Most of the variations in tracer concentration observed in the profile time series were related to changes in wind direction as opposed to changes in turbulence. As a simple analysis tool for emergency response, maximum normalized concentration curves were developed with 5-minute averaged measurements. These curves give the maximum concentration (normalized by the release rate) that would be observed as a function of downwind distance in an urban area. The 5-min data resulted in greater concentrations than predicted with a simple Gaussian plume model. However, the curve compared well with results from a computational fluid dynamics simulation. This dispersion dataset is a valuable asset not only for refining air quality models, but also for developing new tools for emergency response personnel in the event of a toxic release.

  19. Vertical and horizontal corneal epithelial thickness profiles determined by ultra-high resolution optical coherence tomography

    PubMed Central

    Du, Chixin; Wang, Jianhua; Cui, Lele; Shen, Meixiao; Yuan, Yimin

    2011-01-01

    Purpose To measure vertical and horizontal thickness profiles of the central and peripheral corneal epithelium and determine if daytime changes occur. Methods Forty eyes of 20 normal subjects were imaged by ultra-high resolution spectral domain optical coherence tomography to profile the corneal epithelial thickness from the edge of Bowman’s layer to the central cornea across the vertical and horizontal meridians. Measurements were made at 10:00 AM and again at 6, 8 hours later. Results The baseline vertical meridional epithelial thickness was thinnest, 42.9±4.1 μm, at the edge of Bowman’s layer in the superior region. It increased in thickness (p<0.01), towards the central cornea. The central epithelium averaged 52.5±2.4 μm, becoming thickest, 55.2±2.5 μm, in the inferior pericentral region. It thinned towards the inferior periphery, reaching 51.3±5.1 μm at the edge of Bowman’s layer (p<0.01). Along the horizontal meridian, the epithelium was thickest at the nasal side, 58.6±5.1 μm, and temporal side, 59.3±6.6 μm, near the edges of Bowman’s layer. It thinned towards the central cornea. There were no significant changes in the epithelial thickness at any location over 8 hours. Conclusion Epithelial thickness varied over the horizontal and vertical meridians and appeared stable during the daytime. PMID:22357393

  20. Demonstration of Aerosol Property Profiling by Multi-wavelength Lidar Under Varying Relative Humidity Conditions

    NASA Technical Reports Server (NTRS)

    Whiteman, D.N.; Veselovskii, I.; Kolgotin, A.; Korenskii, M.; Andrews, E.

    2008-01-01

    The feasibility of using a multi-wavelength Mie-Raman lidar based on a tripled Nd:YAG laser for profiling aerosol physical parameters in the planetary boundary layer (PBL) under varying conditions of relative humidity (RH) is studied. The lidar quantifies three aerosol backscattering and two extinction coefficients and from these optical data the particle parameters such as concentration, size and complex refractive index are retrieved through inversion with regularization. The column-integrated, lidar-derived parameters are compared with results from the AERONET sun photometer. The lidar and sun photometer agree well in the characterization of the fine mode parameters, however the lidar shows less sensitivity to coarse mode. The lidar results reveal a strong dependence of particle properties on RH. The height regions with enhanced RH are characterized by an increase of backscattering and extinction coefficient and a decrease in the Angstrom exponent coinciding with an increase in the particle size. We present data selection techniques useful for selecting cases that can support the calculation of hygroscopic growth parameters using lidar. Hygroscopic growth factors calculated using these techniques agree with expectations despite the lack of co-located radiosonde data. Despite this limitation, the results demonstrate the potential of multi-wavelength Raman lidar technique for study of aerosol humidification process.

  1. Using Airborne High Spectral Resolution Lidar Data to Evaluate Combined Active Plus Passive Retrievals of Aerosol Extinction Profiles

    NASA Technical Reports Server (NTRS)

    Burton, S. P.; Ferrare, R. A.; Kittaka, C.; Hostetler, C. A.; Hair, J. W.; Obland, M. D.; Rogers, R. R.; Cook, A. L.; Haper, D. B.

    2008-01-01

    Aerosol extinction profiles are derived from backscatter data by constraining the retrieval with column aerosol optical thickness (AOT), for example from coincident MODIS observations and without reliance on a priori assumptions about aerosol type or optical properties. The backscatter data were acquired with the NASA Langley High Spectral Resolution Lidar (HSRL). The HSRL also simultaneously measures extinction independently, thereby providing an ideal data set for evaluating the constrained retrieval of extinction from backscatter. We will show constrained extinction retrievals using various sources of column AOT, and examine comparisons with the HSRL extinction measurements and with a similar retrieval using data from the CALIOP lidar on the CALIPSO satellite.

  2. A look inside the San Andreas Fault at Parkfield through vertical seismic profiling.

    PubMed

    Chavarria, J Andres; Malin, Peter; Catchings, Rufus D; Shalev, Eylon

    2003-12-05

    The San Andreas Fault Observatory at Depth pilot hole is located on the southwestern side of the Parkfield San Andreas fault. This observatory includes a vertical seismic profiling (VSP) array. VSP seismograms from nearby microearthquakes contain signals between the P and S waves. These signals may be P and S waves scattered by the local geologic structure. The collected scattering points form planar surfaces that we interpret as the San Andreas fault and four other secondary faults. The scattering process includes conversions between P and S waves, the strengths of which suggest large contrasts in material properties, possibly indicating the presence of cracks or fluids.

  3. A Look Inside the San Andreas fault at Parkfield Through Vertical Seismic Profiling

    USGS Publications Warehouse

    Chavarria, J.A.; Malin, P.; Catchings, R.D.; Shalev, E.

    2003-01-01

    The San Andreas Fault Observatory at Depth pilot hole is located on the southwestern side of the Parkfield San Andreas fault. This observatory includes a vertical seismic profiling (VSP) array. VSP seismograms from nearby micro-earthquakes contain signals between the P and S waves. These signals may be P and S waves scattered by the local geologic structure. The collected scattering points form planar surfaces that we interpret as the San Andreas fault and four other secondary faults. The scattering process includes conversions between P and S waves, the strengths of which suggest large contrasts in material properties, possibly indicating the presence of cracks or fluids.

  4. Vertical profiling of ozone and meteorological parameters in the lower atmosphere using kite and balloon platforms

    NASA Astrophysics Data System (ADS)

    Knapp, Karl Glenn

    Vertical profiles of ozone mixing ratio, water vapor mixing ratio, temperature and pressure collected as part of the North Atlantic Regional Experiment (NARE) are presented. Two field campaigns to the Maritime Provinces of Canada are described. Thirty-nine profiles collected at Cape Sable Island, Nova Scotia, Canada during the period August 8-28, 1993 illustrate the complex vertical stratification and temporal variability of the lower atmosphere during periods of transport of pollutants to the sampling site. Transport phenomena resulted in pollution events in which ozone at ground level remained in the 20-40 ppbv range while mixing ratios of 90-130 ppbv were observed above ~300 meters. Back trajectories indicate that these highly elevated levels of ozone are attributable to source regions in the eastern United States. Vertical stratification of the lower atmosphere was also present during transport of Canadian air to the sampling site, while marine air did not exhibit layering characteristic of air masses originating from continental source regions. Vertical profiles collected at Ferryland Downs, Newfoundland, Canada during August 3-13, 1995 suggest a potentially important upper atmospheric summertime source of ozone to the Maritime Provinces of Canada. Thirty-four profiles collected during an intensive sampling period, from August 4-7, exhibit layers of ozone reaching 100 ppbv associated with water vapor mixing ratios as low as 0.1 g kg-1. These layers were observed between 2 and 5 km in altitude, with no evidence of dry, ozone-rich layers observed at ground level. Data from free launch balloon soundings during the two weeks prior to the kite/tethered-balloon experiment provide evidence that the dry, ozone-rich air originated at the tropopause. A newly discovered chemiluminescence reaction of nitrogen dioxide with an oxalate ester is described. This reaction is found to be highly solvent specific, and selective to nitrogen dioxide. No chemiluminescence reaction

  5. Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations

    NASA Astrophysics Data System (ADS)

    Jähn, M.; Muñoz-Esparza, D.; Chouza, F.; Reitebuch, O.

    2015-08-01

    Large eddy simulations (LES) are performed for the area of the Caribbean island Barbados to investigate island effects on boundary layer modification, cloud generation and vertical mixing of aerosols. 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 layer forcing, we use the cell perturbation method based on finite amplitude perturbations. In this work, this method is for the first time tested and validated for moist boundary layer 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 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 layer 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 layer depth and location. Saharan dust layers that reach Barbados via long-range transport over the North Atlantic are included as passive tracers in the model. Effects of layer thinning, subsidence and turbulent downward transport near the layer bottom at z ~ 1800 m become apparent. The exact position of these layers 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 formation of the daytime convective plume and the mean vertical wind structure.

  6. Aerosol profiles determined with lidar and sun-photometer over the Pearl River Delta, China.

    NASA Astrophysics Data System (ADS)

    Heese, B.; Althausen, D.; Bauditz, M.; Deng, R.; Bao, R.; Li, Z.

    2012-04-01

    The priority program "Megacities-Megachallenge - Informal Dynamics of Global Change" is a large interdisciplinary project funded by the German Research Foundation (DFG). One of the subproject deals with mega-urbanisation in the Pearl River Delta, South-China, with special respect to particulate air pollution and public health. In the frame of this subproject the vertical distribution of aerosol optical properties are investigated by measurements with the multiwavelength-Raman-polarization lidar PollyXT of the IfT. The instrument can measure the particle backscatter coefficient at 355 nm, 532 nm, and 1064 nm, the particle extinction coefficients at 355 nm and 532 nm, and the particle linear depolarization ratio at 532 nm. These measurements are supported by a dual-polar sun photometer that provides height integrated data as the aerosol optical depth and the degree of linear depolarization. These instruments are placed at the East campus of the Sun Yat-sen University in Guangzhou, China. Guangzhou and the Pearl River Delta is a developing area with currently around 11 Million inhabitants. The measurements started in November 2011 and are supposed to continue for at least half a year covering the late autumn and winter season and parts of the spring season. Extensions of the measurements towards a whole seasonal cycle are planned. Thus, different meteorological conditions will lead to particle transport from several source regions. Different aerosol types are expected to be observed during the measurement period: urban particles from local and regional sources as well as dust from the deserts in Central Asia. The observed particles can be distinguished by analyzing their optical properties at several wavelengths. In particular, the depolarization measurements from both instruments promise a better determination of the particle shape.

  7. Aerosol and cloud observations with a CO2 backscatter lidar on the NASA DC-8 GLOBE Pacific Missions

    NASA Technical Reports Server (NTRS)

    Menzies, Robert T.; Tratt, David M.

    1991-01-01

    The paper presents an airborne backscatter lidar developed to fly multiple times on the NASA DC-8 research aircraft and measure vertical profiles of aerosol and cloud backscatter throughout the vertical extent of the troposphere, with emphasis on coverage of the range of latitudes. The lidar instrument characteristics are summarized and the calibration procedures are described. Results of aerosol and cloud observations are presented.

  8. Vertical velocity and turbulence aspects during Mistral events as observed by UHF wind profilers

    NASA Astrophysics Data System (ADS)

    Caccia, J.; Guénard, V.; Benech, B.; Campistron, B.; Drobinski, P.

    2004-11-01

    The general purpose of this paper is to experimentally study mesoscale dynamical aspects of the Mistral in the coastal area located at the exit of the Rhône-valley. The Mistral is a northerly low-level flow blowing in southern France along the Rhône-valley axis, located between the French Alps and the Massif Central, towards the Mediterranean Sea. The experimental data are obtained by UHF wind profilers deployed during two major field campaigns, MAP (Mesoscale Alpine Program) in autumn 1999, and ESCOMPTE (Expérience sur Site pour COntraindre les Modèles de Pollution atmosphériques et de Transports d'Emission) in summer 2001. Thanks to the use of the time evolution of the vertical profile of the horizontal wind vector, recent works have shown that the dynamics of the Mistral is highly dependent on the season because of the occurrence of specific synoptic patterns. In addition, during summer, thermal forcing leads to a combination of sea breeze with Mistral and weaker Mistral due to the enhanced friction while, during autumn, absence of convective turbulence leads to substantial acceleration as low-level jets are generated in the stably stratified planetary boundary layer. At the exit of the Rhône valley, the gap flow dynamics dominates, whereas at the lee of the Alps, the dynamics is driven by the relative contribution of "flow around" and "flow over" mechanisms, upstream of the Alps. This paper analyses vertical velocity and turbulence, i.e. turbulent dissipation rate, with data obtained by the same UHF wind profilers during the same Mistral events. In autumn, the motions are found to be globally and significantly subsident, which is coherent for a dry, cold and stable flow approaching the sea, and the turbulence is found to be of pure dynamical origin (wind shears and mountain/lee wave breaking), which is coherent with non-convective situations. In summer, due to the ground heating and to the interactions with thermal circulation, the vertical motions are

  9. Improving Aerosol and Visibility Forecasting Capabilities Using Current and Future Generations of Satellite Observations

    DTIC Science & Technology

    2015-08-27

    of the study period, a 3-D CALIOP DA scheme, which is coupled with 2D aerosol optical depth ( AOD ) assimilation using MODIS and MISR aerosol data, has...with the support of this project) has been developed by using the variance in radiances within an artificial light source to retrieve AOD (McHardy et... AOD ) data and lidar vertical aerosol extinction profiles from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIOP) has been

  10. Vertical velocity variance in the mixed layer from radar wind profilers

    USGS Publications Warehouse

    Eng, K.; Coulter, R.L.; Brutsaert, W.

    2003-01-01

    Vertical velocity variance data were derived from remotely sensed mixed layer turbulence measurements at the Atmospheric Boundary Layer Experiments (ABLE) facility in Butler County, Kansas. These measurements and associated data were provided by a collection of instruments that included two 915 MHz wind profilers, two radio acoustic sounding systems, and two eddy correlation devices. The data from these devices were available through the Atmospheric Boundary Layer Experiment (ABLE) database operated by Argonne National Laboratory. A signal processing procedure outlined by Angevine et al. was adapted and further built upon to derive vertical velocity variance, w_pm???2, from 915 MHz wind profiler measurements in the mixed layer. The proposed procedure consisted of the application of a height-dependent signal-to-noise ratio (SNR) filter, removal of outliers plus and minus two standard deviations about the mean on the spectral width squared, and removal of the effects of beam broadening and vertical shearing of horizontal winds. The scatter associated with w_pm???2 was mainly affected by the choice of SNR filter cutoff values. Several different sets of cutoff values were considered, and the optimal one was selected which reduced the overall scatter on w_pm???2 and yet retained a sufficient number of data points to average. A similarity relationship of w_pm???2 versus height was established for the mixed layer on the basis of the available data. A strong link between the SNR and growth/decay phases of turbulence was identified. Thus, the mid to late afternoon hours, when strong surface heating occurred, were observed to produce the highest quality signals.

  11. Tropical Forest Biomass Estimation from Vertical Fourier Transforms of Lidar and InSAR Profiles

    NASA Astrophysics Data System (ADS)

    Treuhaft, R. N.; Goncalves, F.; Drake, J.; Hensley, S.; Chapman, B. D.; Michel, T.; Dos Santos, J. R.; Dutra, L.; Graca, P. A.

    2010-12-01

    Structural forest biomass estimation from lidar or interferometric SAR (InSAR) has demonstrated better performance than radar-power-based approaches for the higher biomasses (>150 Mg/ha) found in tropical forests. Structural biomass estimation frequently regresses field biomass to some function of forest height. With airborne, 25-m footprint lidar data and fixed-baseline C-band InSAR data over tropical wet forests of La Selva Biological Station, Costa Rica, we compare the use of Fourier transforms of vertical profiles at a few frequencies to the intrinsically low-frequency “average height”. RMS scatters of Fourier-estimated biomass about field-measured biomass improved by 40% and 20% over estimates base on average height from lidar and fixed-baseline InSAR, respectively. Vertical wavelengths between 14 and 100 m were found to best estimate biomass. The same airborne data acquisition over La Selva was used to generate many 10’s of repeat-track L-band InSAR baselines with time delays of 1-72 hours, and vertical wavelengths of 5-100 m. We will estimate biomass from the Fourier transforms of L-band radar power profiles (InSAR complex coherence). The effects of temporal decorrelation will be modeled in the Fourier domain to try to model and reduce their impact. Using L-band polarimetric interferometry, average heights will be estimated as well and biomass regression performance compared to the Fourier transform approach. The more traditional approach of using L-band radar polarimetry will also be compared to structural biomass estimation.

  12. Vertical Profiles of Carbonyl Sulfide, Halocarbons, and Benzene Over North America

    NASA Astrophysics Data System (ADS)

    Montzka, S. A.; Calvert, P.; Hall, B.; Elkins, J. W.; Miller, L.; Watson, A.; Sweeney, C.; Tans, P.

    2005-12-01

    A NOAA sampling program to measure vertical profiles of CO{_2}, CH{_4}, N{_2}O, and other gases within the lower atmosphere has been expanded to allow measurements of carbonyl sulfide (COS), CFCs, HCFCs, HFCs, chlorocarbons, bromocarbons, methyl iodide, and benzene. Bimonthly to monthly profiles for these gases have been obtained since September 2004 from flasks collected onboard aircraft at altitudes up to 8 km above sea level at 10 continental and 2 coastal sites in North America. The wide range of gases being measured aid in identifying many different influences on sampled air, such as combustion, input from the oceans, urban emissions, non-urban terrestrial emissions, uptake by vegetation and soils, and vertical mixing. Based upon co-elevated mixing ratios of halocarbons and carbon monoxide or halocarbons and C{_2}Cl{_4}, we anticipate that this sampling program has the potential to provide continental-scale emissions estimates for non-CO{_2} gases that are currently regulated, for example by the Clean Air Act and the Montreal Protocol of Substance that Deplete the Ozone Layer, and for gases listed in the Kyoto Protocol that may be regulated in the future. In addition to the observation of urban pollution and burning plumes, strong and persistent vertical gradients have been observed that vary with season for COS, methyl halides, and chloroform. The results for COS are particularly dramatic, as they show substantially reduced mixing ratios in the continental boundary layer during the growing season. The spatial patterns and seasonality are qualitatively consistent with uptake of COS by photosynthetically active vegetation, though the relative importance of COS loss to soils is poorly constrained. These results will be compared to NOAA ground-based measurements that show strong seasonal variations for COS that are closely tied to those observed for CO{_2}, and the implications of these results on the hypothesis that COS could provide a proxy for gross vegetative

  13. One year of vertical wind profiles measurements at a Mediterranean coastal site of South Italy

    NASA Astrophysics Data System (ADS)

    Calidonna, Claudia Roberta; Avolio, Elenio; Federico, Stefano; Gullì, Daniel; Lo Feudo, Teresa; Sempreviva, Anna Maria

    2015-04-01

    In order to develop wind farms projects is challenging to site them on coastal areas both onshore and offshore as suitable sites. Developing projects need high quality databases under a wide range of atmospheric conditions or high resolution models that could resolve the effect of the coastal discontinuity in the surface properties. New parametrizations are important and high quality databases are also needed for formulating them. Ground-based remote sensing devices such as lidars have been shown to be functional for studying the evolution of the vertical wind structure coastal atmospheric boundary layer both on- and offshore. Here, we present results from a year of vertical wind profiles, wind speed and direction, monitoring programme at a site located in the Italian Calabria Region, Central Mediterranean, 600m from the Thyrrenian coastline, where a Lidar Doppler, ZephIr (ZephIr ltd) has been operative since July 2013. The lidar monitors wind speed and direction from 10m up to 300m at 10 vertical levels with an average of 10 minutes and it is supported by a metmast providing: Atmospheric Pressure, Solar Radiation, Precipitation, Relative Humidity, Temperature,Wind Speed and Direction at 10m. We present the characterization of wind profiles during one year period according to the time of the day to transition periods night/day/night classified relating the local scale, breeze scale, to the large scale conditions. The dataset is also functional for techniques for short-term prediction of wind for the renewable energy integration in the distribution grids. The site infrastructure is funded within the Project "Infrastructure of High Technology for Environmental and Climate Monitoring" (I-AMICA) (PONa3_00363) by the Italian National Operative Program (PON 2007-2013) and European Regional Development Fund. Real-time data are show on http://www.i-amica.it/i-amica/?page_id=1122.

  14. Vertical structure of the upper ocean from profiles fitted to physically consistent functional forms

    NASA Astrophysics Data System (ADS)

    González-Pola, César; Fernández-Díaz, Julio M.; Lavín, Alicia

    2007-11-01

    A method for characterizing the upper ocean structure is developed. Each temperature (density) profile is fitted by an ideal function based on the assumption that the permanent and seasonal thermoclines can be approximated respectively by steady state and transients of turbulent-diffusive processes and that the mixed layer can advance sharply under external forcing. The ideal profile is composed of two pieces joined at the mixed layer depth (MLD). The upper part is a constant; the part below the MLD is a product of an exponential decay and a Gaussian, representing the seasonal thermocline and decaying asymptotically to a straight line that describes the permanent thermocline. The composition of an exponential decay and a Gaussian accurately fits a wide family of solutions of the diffusion equation and includes the case of a shift of the boundary. The ideal fit for each profile relies on six adjustable parameters including the MLD. As the function is non-linear and non-differentiable, a Differential Evolution optimization algorithm is proposed to make the fitting. The solution gives a good estimate of the MLD based on the topology of the profile. It also provides a measure of the gradient and the shape of each profile, which are intuitive parameters for characterizing the upper ocean structure with direct applicability in ecosystem models. The algorithm is applied to a time series of monthly conductivity-temperature-depth (CTD) profiles from a hydrographical station in the southern Bay of Biscay. The construction of a local climatology of the vertical structure evolution (mixed layer development) is presented as a practical application. Other potential uses of the method are also discussed.

  15. High-latitude topside ionospheric vertical electron density profile changes in response to large magnetic storms

    NASA Astrophysics Data System (ADS)

    Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir A.; Truhlik, Vladimir; Wang, Yongli; Bilitza, Dieter; Fung, Shing F.

    2016-05-01

    Large magnetic-storm-induced changes were detected in high-latitude topside vertical electron density profiles Ne(h) in a database of profiles and digital topside ionograms, from the International Satellites for Ionospheric Studies (ISIS) program, that enabled Ne(h) profiles to be obtained in nearly the same region of space before, during, and after a major magnetic storm (Dst < -100 nT). Storms where Ne(h) profiles were available in the high-latitude Northern Hemisphere had better coverage of solar wind parameters than storms with available Ne(h) profiles in the high-latitude Southern Hemisphere. Large Ne(h) changes were observed during all storms, with enhancements and depletions sometimes near a factor of 10 and 0.1, respectively, but with substantial differences in the responses in the two hemispheres. Large spatial and/or temporal Ne(h) changes were often observed during Dst minimum and during the storm recovery phase. The storm-induced Ne(h) changes were the most pronounced and consistent in the Northern Hemisphere in that large enhancements were observed during winter nighttime and large depletions during winter and spring daytime. The limited available cases suggested that these Northern Hemisphere enhancements increased with increases of the time-shifted solar wind velocity v, magnetic field B, and with more negative values of the B components except for the highest common altitude (1100 km) of the profiles. There was also some evidence suggesting that the Northern Hemisphere depletions were related to changes in the solar wind parameters. Southern Hemisphere storm-induced enhancements and depletions were typically considerably less with depletions observed during summer nighttime conditions and enhancements during summer daytime and fall nighttime conditions.

  16. Ground based lidar and microwave radiometry synergy for high vertically resolved thermodynamic profiling

    NASA Astrophysics Data System (ADS)

    Barrera-Verdejo, M.; Crewell, S.; Löhnert, U.; Orlandi, E.; Di Girolamo, P.

    2015-05-01

    Continuous monitoring of atmospheric humidity and temperature profiles is important for many applications, e.g. assessment of atmospheric stability and cloud formation. While lidar measurements can provide high vertical resolution albeit with limited coverage, microwave radiometers receive information throughout the troposphere though their vertical resolution is poor. In order to overcome these specific limitations the synergy of a Microwave Radiometer (MWR) and a Raman Lidar (RL) system is presented in this work. The retrieval algorithm that combines these two instruments is an Optimal Estimation Method (OEM) that allows for a uncertainty analysis of the retrieved profiles. The OEM combines measurements and a priori information taking the uncertainty of both into account. The measurement vector consists of a set of MWR brightness temperatures and RL water vapor profiles. The method is applied for a two month field campaign around Jülich, Germany for clear sky periods. Different experiments are performed to analyse the improvements achieved via the synergy compared to the individual retrievals. When applying the combined retrieval, on average the theoretically determined absolute humidity error can be reduced by 59.8% (37.9%) with respect to the retrieval using only-MWR (only-RL) data. The analysis in terms of degrees of freedom for signal reveals that most information is gained above the usable lidar range. The retrieved profiles are further evaluated using radiosounding and GPS water vapor measurements. Within a single case study we also explore the potential of the OEM for deriving the relative humidity profile, which is especially interesting to study cloud formation in the vicinity of cloud edges. To do so temperature information is added both from RL and MWR. For temperature, it is shown that the error is reduced by 47.1% (24.6%) with respect to the only-MWR (only-RL) profile. Due to the use of MWR brightness temperatures at multiple elevation angles, the

  17. First regional vertical profiles of CO2: Can we verify reported emissions?

    NASA Astrophysics Data System (ADS)

    Lindenmaier, R.; Hase, F.; Dubey, M.; Lee, S.; Costigan, K. R.; Henderson, B. G.

    2013-12-01

    CO2 is known as the most important greenhouse gas (GHG), its rising levels in the Earth's atmosphere resulting in global warming. Both atmospheric CO2 and climate change are accelerating, urging scientists to find solutions to stabilize CO2 and other GHGs. Power plants are the largest contributors to the manmade CO2 emissions. Remote observations of CO2 provide a method to verify CO2 emissions for an enforceable climate treaty. Column CO2 measurements are made routinely by the Total Carbon Column Observing Network (TCCON) and satellites. The column CO2 signals of power plants are typically small 1-10 ppm that are much smaller than the signals in the boundary layer (20-100 ppm). We resolve the vertical profile of CO2 in a power plant dominated area for the first time. We directly interrogate the power plant plume and see large signals in the lower troposphere. We demonstrate that in addition to the total columns, CO2 vertical profiles determined from ground-based Fourier transform infrared (FTIR) spectra can be used to detect the enhancement of CO2 in the boundary layer. Measurements were made at the Four Corners site, in the San Juan Basin, an arid region with two large coal-fired power plants that emit approximately 30 Mton CO2/year. We used the PROFFIT profile retrieval software to show that the power plants' signatures are visible in our CO2 profiles. We also compare the results with the World Research and Forecasting-Chemistry (WRF-Chem) model driven with real time emissions monitored in the stack of the power plants. The measured profiles indicate the presence of the power plant plume within the first 7 km, and are in good agreement with the modeled profiles. We show that the model simulations are found to be within 4% of the measurements, demonstrating that we can verify emissions to better than 5%. Results from a preliminary exploration of the compact low-resolution mini FTS will be also presented. This new robust off-the shelf instrument permits the study

  18. ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Vertical Air Motion (williams-vertair)

    SciTech Connect

    Williams, Christopher; Jensen, Mike

    2012-11-06

    This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

  19. Impact of aerosol hygroscopic growth on the direct aerosol radiative effect in summer on North China Plain

    NASA Astrophysics Data System (ADS)

    Kuang, Y.; Zhao, C. S.; Tao, J. C.; Bian, Y. X.; Ma, N.

    2016-12-01

    In this paper, relative humidity (RH) profiles and their impacts on the vertical variations of aerosol optical properties and the direct aerosol radiative effect (DARE) have been investigated based on surface measurements from the Haze in China campaign and sounding data from the North China Plain. Among the profiles obtained from July to September in 2008, about half have RHs greater than 80% within the mixed layer. The vertical variations in the aerosol optical properties at ambient RH, including the extinction coefficient (σext), single scattering albedo (SSA) and asymmetry factor (g), are remarkably different from the variations in the dry aerosols and are highly dependent on the RH profiles. Increases of the aerosol optical depth and column-averaged SSA and g due to aerosol water uptake can reach up to 64%, 0.052 and 0.079, respectively. The fractional contribution to the instantaneous DARE at the top of the atmosphere due to aerosol hygroscopic growth reaches 60% in high RH profiles. DARE estimates can be significantly biased if the RH dependence of SSA or g is not considered. We suggest that if their vertical profiles or column-averaged values are absent, then the ambient values of SSA and g at the surface should be used rather than the values of SSA and g obtained from dry aerosols when estimating DAREs.

  20. Evaluating the impact of assimilating CALIOP-derived aerosol extinction profiles on a global mass transport model

    NASA Astrophysics Data System (ADS)

    Zhang, Jianglong; Campbell, James R.; Reid, Jeffrey S.; Westphal, Douglas L.; Baker, Nancy L.; Campbell, William F.; Hyer, Edward J.

    2011-07-01

    Coupled two/three-dimensional variational (2D/3DVAR) assimilation of aerosol physical properties retrieved from the Moderate Resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging Spectroradiometer (MISR) and Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite-borne instruments is described for the U. S. Navy Aerosol Analysis and Prediction System (NAAPS) global aerosol mass transport model. Coupled 2D/3DVAR assimilation for NAAPS is evaluated for 48-hr forecast cycles, computed four times daily in six-hour intervals, versus stand-alone 2DVAR assimilation of MODIS and MISR aerosol optical depths (AOD). Both systems are validated against AERONET ground-based sun photometer measurements of AOD. Despite a narrow nadir viewing swath and more than 2700 km of equatorial separation between orbits, satellite lidar data assimilation elicits a positive model response. Improvements in analysis and forecast AOD absolute errors are found over both land and maritime AERONET sites. The primary impact to the model from 3DVAR assimilation is the redistribution of aerosol mass into the boundary layer, though the process is sensitive to parameterization of vertical error correlation lengths.

  1. Vertical radar profiles for the calibration of unsaturated flow models under dynamic water table conditions

    NASA Astrophysics Data System (ADS)

    Cassiani, G.; Gallotti, L.; Ventura, V.; Andreotti, G.

    2003-04-01

    The identification of flow and transport characteristics in the vadose zone is a fundamental step towards understanding the dynamics of contaminated sites and the resulting risk of groundwater pollution. Borehole radar has gained popularity for the monitoring of moisture content changes, thanks to its apparent simplicity and its high resolution characteristics. However, cross-hole radar requires closely spaced (a few meters), plastic-cased boreholes, that are rarely available as a standard feature in sites of practical interest. Unlike cross-hole applications, Vertical Radar Profiles (VRP) require only one borehole, with practical and financial benefits. High-resolution, time-lapse VRPs have been acquired at a crude oil contaminated site in Trecate, Northern Italy, on a few existing boreholes originally developed for remediation via bioventing. The dynamic water table conditions, with yearly oscillations of roughly 5 m from 6 to 11 m bgl, offers a good opportunity to observe via VRP a field scale drainage-imbibition process. Arrival time inversion has been carried out using a regularized tomographic algorithm, in order to overcome the noise introduced by first arrival picking. Interpretation of the vertical profiles in terms of moisture content has been based on standard models (Topp et al., 1980; Roth et al., 1990). The sedimentary sequence manifests itself as a cyclic pattern in moisture content over most of the profiles. We performed preliminary Richards' equation simulations with time varying later table boundary conditions, in order to estimate the unsaturated flow parameters, and the results have been compared with laboratory evidence from cores.

  2. Sampling the Vertical Moisture Structure of an Atmospheric River Event Using Airborne GPS Radio Occultation Profiling

    NASA Astrophysics Data System (ADS)

    Haase, J. S.; Malloy, K.; Murphy, B.; Sussman, J.; Zhang, W.

    2015-12-01

    Atmospheric rivers (ARs) are of high concern in California, bringing significant rain to the region over extended time periods of up to 5 days, potentially causing floods, and more importantly, contributing to the Sierra snowpack that provides much of the regional water resources. The CalWater project focuses on predicting the variability of the West Coast water supply, including improving AR forecasting. Unfortunately, data collection over the ocean remains a challenge and impacts forecasting accuracy. One novel technique to address this issue includes airborne GPS radio occultation (ARO), using broadcast GPS signals from space to measure the signal ray path bending angle and refractivity to retrieve vertical water vapor profiles. The Global Navigation Satellite System Instrument System for Multistatic and Occultation Sensing (GISMOS) system was developed for this purpose for recording and processing high-sample rate (10MHz) signals in the lower troposphere. Previous studies (Murphy et al, 2014) have shown promising results in acquiring airborne GPS RO data, comparing it to dropsondes and numerical weather models. CalWater launched a field campaign in the beginning of 2015 which included testing GISMOS ARO on the NOAA GIV aircraft for AR data acquisition, flying into the February 6th AR event that brought up to 35 cm of rain to central California. This case study will compare airborne GPS RO refractivity profiles to the NCEP-NCAR final reanalysis model and dropsonde profiles. We will show the data distribution and explain the sampling characteristics, providing high resolution vertical information to the sides of the aircraft in a manner complementary to dropsondes beneath the flight track. We will show how this method can provide additional reliable data during the development of AR storms.

  3. Vertical Cloud Climatology During TC4 Derived from High-Altitude Aircraft Merged Lidar and Radar Profiles

    NASA Technical Reports Server (NTRS)

    Hlavka, Dennis; Tian, Lin; Hart, William; Li, Lihua; McGill, Matthew; Heymsfield, Gerald

    2009-01-01

    Aircraft lidar works by shooting laser pulses toward the earth and recording the return time and intensity of any of the light returning to the aircraft after scattering off atmospheric particles and/or the Earth s surface. The scattered light signatures can be analyzed to tell the exact location of cloud and aerosol layers and, with the aid of a few optical assumptions, can be analyzed to retrieve estimates of optical properties such as atmospheric transparency. Radar works in a similar fashion except it sends pulses toward earth at a much larger wavelength than lidar. Radar records the return time and intensity of cloud or rain reflection returning to the aircraft. Lidar can measure scatter from optically thin cirrus and aerosol layers whose particles are too small for the radar to detect. Radar can provide reflection profiles through thick cloud layers of larger particles that lidar cannot penetrate. Only after merging the two instrument products can accurate measurements of the locations of all layers in the full atmospheric column be achieved. Accurate knowledge of the vertical distribution of clouds is important information for understanding the Earth/atmosphere radiative balance and for improving weather/climate forecast models. This paper describes one such merged data set developed from the Tropical Composition, Cloud and Climate Coupling (TC4) experiment based in Costa Rica in July-August 2007 using the nadir viewing Cloud Physics Lidar (CPL) and the Cloud Radar System (CRS) on board the NASA ER-2 aircraft. Statistics were developed concerning cloud probability through the atmospheric column and frequency of the number of cloud layers. These statistics were calculated for the full study area, four sub-regions, and over land compared to over ocean across all available flights. The results are valid for the TC4 experiment only, as preferred cloud patterns took priority during mission planning. The TC4 Study Area was a very cloudy region, with cloudy

  4. Wavelength dependent near-range lidar profiling of smog aerosol over Athens

    NASA Astrophysics Data System (ADS)

    Stachlewska, Iwona S.; Marinou, Eleni; Engelmann, Ronny; Costa Surós, Montserrat; Kottas, Mickael; Baars, Holger; Janicka, Lucja; Solomos, Stavros; Heese, Birgit; Kumala, Wojciech; Tsekeri, Alexandra; Binietoglou, Ioannis; Markowicz, Krzysztof M.; Amiridis, Vassilis; Balis, Dimitris; Althausen, Dietrich; Wandinger, Ulla; Ansmann, Albert

    2016-04-01

    Recently, the ACTRIS2 JRA1 field campaign focusing on joint remote and in-situ sensing of absorbing aerosols has been conducted in Athens (http://actris-athens.eu). In the frame of the ACTRIS2 BL-Smog TNA, co-located measurements of the near-range lidar receiver (NARLa) of the University of Warsaw with the multi-wavelength PollyXT lidar of the National Observatory of Athens were performed. The excellent capacities of the PollyXT-NOA lidar, equipped with eight far-range channels (355, 355s, 387, 407, 532, 532s, 607, and 1064nm) and two near-range channels (532 and 607 nm), were enhanced by integrating the NARLa for simultaneous observations. By using the NARLa, equipped with the elastic channels (355 and 532nm) and Raman channels (387 and 607nm), the wavelength dependence of the aerosol particles properties within boundary layer was captured. The dominant conditions observed during the JRA1 period were the fresh winter smog layers occurring in lowermost boundary layer over Athens. NARLa provided profiles as close to surface as 50m, thus the data obtained in the near-range were used for the incomplete overlap region of the far-field channels. With NARLa we assessed the overlap at 355 and 532nm wavelengths and concluded on the possibility of using the single near-range 532 nm channel for the overlap correction in both VIS and UV channels of the PollyXT-NOA. As a result, the obtained lidar profiles are expected to be more consistent with the sunphotometer measurements. In the future, the GARRLiC code can be applied on the synergy of combined near and far range lidar profiles with AERONET data sets in order to study improvement on the inversion results.

  5. Vertical and horizontal profiles of airborne particulate matter near major roads in Macao, China

    NASA Astrophysics Data System (ADS)

    Wu, Ye; Hao, Jiming; Fu, Lixin; Wang, Zhishi; Tang, Uwa

    Vertical profiles, horizontal profiles and size distribution of airborne particulate matter were measured near major roads in Macao using DustTrak and TEOM monitors. A significant decrease in the concentrations of PM 10, PM 2.5 and PM 1, as the height above the ground increases from 2 to 79 m, was found. At the height of 79 m, the concentrations of PM 10, PM 2.5 and PM 1, decrease to about 60%, 62% and 80% of the maximum occurring at 2 m above the ground, respectively. However, the horizontal profiles near another major road revealed there was no significant trend of decrease in concentrations of particulate matter as the distance from the road increases. Over the total measured distance (0-228 m), the maximum decreases of PM 10, PM 2.5 and PM 1 are only 7%, 9% and 10%, of the maximum occurring at 2 m from the road, respectively. The daytime averaged PM 2.5 and PM 1 contribute 66-67% and 51-60%, respectively, of the total PM 10 mass after the particle readings by DustTrak were recalibrated by TEOM. It showed that fine particles and submicrometer particles contributed a major part of PM 10 at the roadside in Macao, which is most likely attributed to the combinations of local sources including exhausted particulate matter from vehicles and resuspended fine dust, and secondary particles (sulfate, nitrate and ammonium) of regional scales.

  6. Vertical distribution and environmental significance of PAHs in soil profiles in Beijing, China.

    PubMed

    Bu, Qing Wei; Zhang, Zhi Huan; Lu, Song; He, Feng Peng

    2009-02-01

    Vertical distribution of both the concentration and composition of polycyclic aromatic hydrocarbons (PAHs) in ten profiles in Beijing has been investigated. The results showed that PAH concentrations and compositions in topsoil from different sampling sites were different. PAH concentrations were much higher in topsoil of the investigated urban area, industrial region, and paddy field with wastewater irrigation than in other areas. Moreover, PAH concentrations in topsoil were much higher than those at greater depth, where the concentrations were relatively consistent in most soil profiles. The fingerprints of PAHs in the samples from topsoil (0-30 cm) in the same profiles were similar and were obviously different from those at greater depth, suggesting that PAH sources were consistent in topsoil samples and were discriminating between topsoil and deeper soils. PAHs in topsoil mainly arose from mixed sources of combustion of liquid fuel, coal, and/or wood, as well as wastewater irrigation, while those at greater depth were derived from soil genesis and the process of soil formation.

  7. Aerosol Classification using Airborne High Spectral Resolution Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Burton, S. P.; Ferrare, R. A.; Hostetler, C. A.; Hair, J. W.; Obland, M. D.; Rogers, R.; Butler, C. F.; Cook, A.; Harper, D.; Froyd, K. D.

    2011-12-01

    The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 aircraft has acquired extensive datasets of aerosol extinction (532 nm), aerosol optical thickness (AOT) (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) profiles during 18 field missions that have been conducted over North America since 2006. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, backscatter color ratio, spectral depolarization ratio) are shown to vary with location and aerosol type. A methodology based on observations of known aerosol types is used to qualitatively classify the extensive set of HSRL aerosol measurements into eight separate types. Several examples are presented showing how the aerosol intensive parameters vary with aerosol type and how these aerosols are classified according to this new methodology. The HSRL-based classification reveals vertical variability of aerosol types during the NASA ARCTAS field experiment conducted over Alaska and northwest Canada during 2008. In two examples derived from flights conducted during ARCTAS, the HSRL classification of biomass burning smoke is shown to be consistent with aerosol types derived from coincident airborne in situ measurements of particle size and composition. The HSRL retrievals of aerosol optical thickness and inferences of aerosol types are used to apportion aerosol optical thickness to aerosol type; results of this analysis are shown for several experiments.

  8. Convection Fingerprints on the Vertical Profiles of Q1 and Q2

    NASA Astrophysics Data System (ADS)

    Chang, C.; Lin, H.; Chou, C.

    2013-12-01

    Different types of tropical convection left their fingerprints on vertical structures of apparent heat source (Q1) and apparent moisture sink (Q2). Profile of deep convection on condensation heating and drying has been well-documented, yet direct assessment of shallow convection remains to be explored. Shallow convection prevails over subtropical ocean, where large-scale subsidence is primarily balanced by radiative cooling and moistening due to surface evaporation instead of moist convection. In this study a united framework is designed to investigate the vertical structures of tropical marine convections in three reanalysis data, including ERA-Interim, MERRA, and CFSR. It starts by sorting and binning data from the lightest to the heaviest rain. Then the differences between two neighboring bins are used to examine the direct effects for precipitation change, in light of the fact that non-convective processes would change slowly from bin to bin. It is shown that all three reanalyses reveal the shallow convective processes in light rain bins, featured by re-evaporating and detraining at the top of boundary layer and lower free troposphere. For heavy rain bins, three reanalyses mainly differ in their numbers and altitudes of heating and drying peaks, implying no universal agreement has been reached on partitioning of cloud populations. Coherent variations in temperature, moisture, and vertical motion are also discussed. This approach permits a systematical survey and comparison of tropical convection in GCM-type models, and preliminary studies of three reanalyses suggest certain degree of inconsistency in simulated convective feedback to large-scale heat and moisture budgets.

  9. Computation of vertical profiles of longwave radiative cooling over the equatorial Pacific

    NASA Technical Reports Server (NTRS)

    Ramsey, Perry G.; Vincent, Dayton G.

    1995-01-01

    An important quantity whose magnitude has not been throughly examined is the vertical distribution of heating in the Tropics. The details of the vertical distribution of heating have a significant impact on a number of phenomena, including the 30-60 day oscillation, sometimes known as the intraseasonal oscillation. Prior attempts to establish the structure of the heating relied on limited field data or assimilated data, coupled with climatological radiative heating parameters. The availability of high quality global-scale datasets has made it possible to make more accurate calculations than were possible a few years ago. An important component of the apparent heat budget is the longwave radiative cooling, which in this paper is found by using the ECMWF/WCRP/TOGA Archive 2 and ISCCP C1 datasets, together with a well-established parameterization scheme. A method is developed that can be used to estimate the vertical structure of cloud amounts based on top-of-atmosphere cloud observations, and the results are used with a wide-band longwave parameterization to produce longwave cooling rates over the tropical Pacific Ocean. Outgoing longwave radiation is calculated and compared the ERBE results. The calculated values are generally higher than those from ERBE, though the spatial distributions are similar. Some significant problems exist with the ECMWF upper-tropospheric water vapor amounts, which could imply uncertainties of 0.5 C/day in the calculated cooling rates. This is comparable to the differences associated with the minimum or random overlap assumptions used to generate cloud profiles.

  10. Characterizing leaf area index (LAI) and vertical foliage profile (VFP) over the United States

    NASA Astrophysics Data System (ADS)

    Tang, H.; Ganguly, S.; Zhang, G.; Hofton, M. A.; Nelson, R. F.; Dubayah, R.

    2016-01-01

    Leaf area index (LAI) and vertical foliage profile (VFP) are among the important canopy structural variables. Recent advances in lidar remote sensing technology have demonstrated the capability of accurately mapping LAI and VFP over large areas. The primary objective of this study was to derive and validate a LAI and VFP product over the contiguous United States (CONUS) using spaceborne waveform lidar data. This product was derived at the footprint level from the Geoscience Laser Altimeter System (GLAS) using a biophysical model. We validated GLAS-derived LAI and VFP across major forest biomes using airborne waveform lidar. The comparison results showed that GLAS retrievals of total LAI were generally accurate with little bias (r2 = 0.67, bias = -0.13, RMSE = 0.75). The derivations of GLAS retrievals of VFP within layers were not as accurate overall (r2 = 0.36, bias = -0.04, RMSE = 0.26), and these varied as a function of height, increasing from understory to overstory - 0 to 5 m layer: r2 = 0.04, bias = 0.09, RMSE = 0.31; 10 to 15 m layer: r2 = 0.53, bias = -0.08, RMSE = 0.22; and 15 to 20 m layer: r2 = 0.66, bias = -0.05, RMSE = 0.20. Significant relationships were also found between GLAS LAI products and different environmental factors, in particular elevation and annual precipitation. In summary, our results provide a unique insight into vertical canopy structure distribution across North American ecosystems. This data set is a first step towards a baseline of canopy structure needed for evaluating climate and land use induced forest changes at the continental scale in the future, and should help deepen our understanding of the role of vertical canopy structure in terrestrial ecosystem processes across varying scales.

  11. An Algorithm to Estimate the Heating Budget from Vertical Hydrometeor Profiles.

    NASA Astrophysics Data System (ADS)

    Tao, Wei-Kuo; Simpson, Joanne; Lang, Stephen; McCumber, Michael; Adler, Robert; Penc, Richard

    1990-12-01

    A simple algorithm to estimate the latent heating of cloud systems from their vertical hydrometer profiles is proposed. The derivation as well as the validation of the algorithm is based on output generated by a non-hydrostatic cloud model with parameterized microphysical processes. Mature and decaying stages of a GATE squall-type convective system have been tested. The algorithm-derived heating budget is in reasonable agreement with the budget predicted by the cloud model. The input to the proposed algorithm can be obtained from either a rain retrieval technique based on information from multichannel passive microwave signals or a kinematic cloud model based on information from Doppler radar wind fields and radar reflectivity patterns. Such an application would have significant implications for spaceborne remote sensing and the large-scale weather prediction data assimilation problem.

  12. Multiple Frequency Contrast Source Inversion Method for Vertical Electromagnetic Profiling: 2D Simulation Results and Analyses

    NASA Astrophysics Data System (ADS)

    Li, Jinghe; Song, Linping; Liu, Qing Huo

    2016-02-01

    A simultaneous multiple frequency contrast source inversion (CSI) method is applied to reconstructing hydrocarbon reservoir targets in a complex multilayered medium in two dimensions. It simulates the effects of a salt dome sedimentary formation in the context of reservoir monitoring. In this method, the stabilized biconjugate-gradient fast Fourier transform (BCGS-FFT) algorithm is applied as a fast solver for the 2D volume integral equation for the forward computation. The inversion technique with CSI combines the efficient FFT algorithm to speed up the matrix-vector multiplication and the stable convergence of the simultaneous multiple frequency CSI in the iteration process. As a result, this method is capable of making quantitative conductivity image reconstruction effectively for large-scale electromagnetic oil exploration problems, including the vertical electromagnetic profiling (VEP) survey investigated here. A number of numerical examples have been demonstrated to validate the effectiveness and capacity of the simultaneous multiple frequency CSI method for a limited array view in VEP.

  13. Shear source multiazimuth near- and far-offset vertical seismic profiles, Asal Rift, Republic of Djibouti

    SciTech Connect

    Hirn, A.; Magnier, S.A. )

    1992-12-10

    A three-component borehole seismic data set obtained in the Asal rift zone shows that azimuthal anisotropy may be present with the fast propagation direction aligned with the present-day rift axis. This is seen on the near- and far-offset vertical seismic profile (VSP) data from the two source points lying parallel to the rift axis. The third orthogonal source point gives propagation times characteristic of near-horizontal paths along the detected slow direction. The reflected VSP wave field contains both P and S energy. The main P and S reflections correlate well and correspond to thin clay and siltstone layers interspersed within the lava flow series. Some evidence exists for a change with depth of the amount or direction of the anisotropy found in the uppermost 400 m.

  14. Algorithmic identification of limnological features in vertical profiles from the Great Lakes

    NASA Astrophysics Data System (ADS)

    Wietsma, T.; Collingsworth, P.; Minsker, B. S.

    2013-12-01

    High volume collection of environmental data in digital format presents a range of challenges for the researcher, from quality control and data management to efficient interpretation of the signal and the development of requisite information technology skills. These challenges have been termed the "data deluge". To aid in efficient data interpretation, we describe several algorithmic approaches for feature identification in signal streams, including gradient estimation, spectral analysis, and the hidden Markov model. These approaches are calibrated and evaluated over vertical temperature profiles from the Great Lakes obtained through the U.S. Environmental Protection Agency. To demonstrate the value of this data science approach, we describe how the algorithms can be integrated with the historical sampling record to yield an expert system that assists field technicians with adaptive sampling.

  15. Does the vertical profile of ethane contain more insight into mixing layer height than carbon monoxide?

    NASA Astrophysics Data System (ADS)

    Herndon, Scott; Yacovitch, Tara; Pusede, Sally; Diskin, Glenn; DiGangi, Joshua; Sachse, Glenn; Crawford, James

    2015-04-01

    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 layer height. 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 layer height 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 layer height.

  16. An algorithm to estimate the heating budget from vertical hydrometeor profiles

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Simpson, Joanne; Mccumber, Michael; Adler, Robert; Lang, Stephen

    1990-01-01

    A simple algorithm to estimate the latent heating of cloud systems from their vertical hydrometeor profiles is proposed. The derivation as well as the validation of the algorithm is based on output generated by a nonhydrostatic cloud model with parameterized microphysical processes. Mature and decaying stages of a GATE squall-type convective system have been tested. The algorithm-derived heating budget is in reasonable agreement with the budget predicted by the cloud model. The input to the proposed algoritm can be obtained from either a rain retrieval technique based on information from multichannel passive microwave signals or a kinematic cloud model based on information from Doppler radar wind fields and radar reflectivity patterns. Such an application would have significant implications for spaceborne remote sensing and the large-scale weather prediction data assimilation problem.

  17. A study on characterization of stratospheric aerosol and gas parameters with the spacecraft solar occultation experiment

    NASA Technical Reports Server (NTRS)

    Chu, W. P.

    1977-01-01

    Spacecraft remote sensing of stratospheric aerosol and ozone vertical profiles using the solar occultation experiment has been analyzed. A computer algorithm has been developed in which a two step inversion of the simulated data can be performed. The radiometric data are first inverted into a vertical extinction profile using a linear inversion algorithm. Then the multiwavelength extinction profiles are solved with a nonlinear least square algorithm to produce aerosol and ozone vertical profiles. Examples of inversion results are shown illustrating the resolution and noise sensitivity of the inversion algorithms.

  18. An evaluation and comparison of vertical profile data from the VISSR Atmospheric Sounder (VAS)

    NASA Technical Reports Server (NTRS)

    Jedlovec, G. J.

    1985-01-01

    A statistical evaluation is used to compared vertical profiles of temperature and moisture derived from VISSR Atmospheric Sounder (VAS) with three different algorithms to that of corresponding rawinsonde measurements for a clear cold environment. To account for time and space discrepancies between the data sets, rawinsonde data were adjusted to be representative of the satellite sounding times. Both rawinsonde and satellite sounding data were objectively analyzed onto a mesoscale grid. These grid point values were compared at 50 mb pressure increments from the surface up to 100 mb. The data were analyed for horizontal and vertical structure, representatives of derived parameters, and significant departure (improvement) from the apriori (first guess) information. Results indicate some rather strong temperature and moisture biases exist in the satellite soundings. Temperature biases of 1 to 4 C and dewpoint biases of 2 to 6 C generally occur in layers where strong inversions are present and vary with time as these atmospheric features evolve. The biases also changes as a function retrieval scheme suggesting limitations and restrictions on the applications of the various techniques. Standard temperature deviations range from 1 to 2 C for each retrieval scheme with maximum values around 800 and 400 mb. Derived parameters (precipitable water and thickness) suffer from similar biases, though to a somewhat lesser extent. Gradients of basic and derived parameters are generally weaker but have good horizontal structure where magnitudes of the parameters are relatively strong. Integrated thermal (temperature) and moisture (precipitable water) parameters show mixed results.

  19. Use of vertical electrical resistivity profiles to characterize the riverbed of losing-disconnected rivers

    NASA Astrophysics Data System (ADS)

    Lamontagne, Sebastien; Davis, Aaron; Crosbie, Russell; Taylor, Andrew; Munday, Tim

    2014-05-01

    There are few field techniques available to estimate infiltration rates from losing-disconnected rivers, where infiltration rates are often constrained by the presence of clay layers with a low hydraulic conductivity. It is hypothesized that, in this environment, the bulk of the infiltration would occur in 'hotspots' where the clay layer is thin or absent. Infiltration was estimated over a 2 km section of Billabong Creek (Murray-Darling Basin, Australia) using vertical electrical sounding (VES) resistivity to characterize the continuity and thickness of the riverbed clay layer. Both a towed in-river survey over the whole study reach and three fixed array measurements at the shoreline at selected areas were used. Using locations with measured high and low resistivity, the resistivity profiles were constrained by coring the riverbed to measure vertical variations in riverbed texture, porewater content and porewater salinity. The VES showed that the clay layer was continuous along the study reach and varied in thickness between 1 m and >4 m. Using a simple steady-state model, infiltration rates along the study reach were estimated to vary between 1700 and 7800 m3 km-1 year-1, with an average of 3400 m3 km-1 year-1. This methodology can provide independent estimates of infiltration rates at a scale suitable for the calibration of regional groundwater models.

  20. Study of aerosol microphysical properties profiles retrieved from ground-based remote sensing and aircraft in-situ measurements during a Saharan dust event

    NASA Astrophysics Data System (ADS)

    Granados-Muñoz, M. J.; Bravo-Aranda, J. A.; Baumgardner, D.; Guerrero-Rascado, J. L.; Pérez-Ramírez, D.; Navas-Guzmán, F.; Veselovskii, I.; Lyamani, H.; Valenzuela, A.; Olmo, F. J.; Titos, G.; Andrey, J.; Chaikovsky, A.; Dubovik, O.; Gil-Ojeda, M.; Alados-Arboledas, L.

    2015-09-01

    In this work we present an analysis of mineral dust optical and microphysical properties obtained from different retrieval techniques applied to active and passive remote sensing measurements, including a comparison with simultaneous in-situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak a Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on the 27 June 2011. Column-integrated properties are provided by sun- and star-photometry which allows a continuous evaluation of the mineral dust optical properties during both day and night-time. Both the Linear Estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically-resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during night-time. LIRIC retrievals reveal several dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 μm3 cm-3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in-situ measurements. This study presents for the first time a comparison of both volume concentration and dust particle polarization ratios measured with in-situ and remote sensing techniques. Results for the depolarization measurements in the dust layer indicate reasonable agreement within the

  1. Vertical Profiles of SO2 and NO2 in the Alberta Oil Sands: MAX-DOAS Measurements and Comparison to in-situ Instrumentation

    NASA Astrophysics Data System (ADS)

    Davis, Zoe; Lobo, Akshay; McLaren, Robert

    2015-04-01

    Understanding the levels of industrially emitted gas pollutants in the Alberta oil sands is essential to making quality environmental management decisions but is currently limited due to scarcity of top-down quantification studies. Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of nitrogen dioxide (NO2) and sulfur dioxide (SO2) , important tropospheric trace gas pollutants, contributes to improved knowledge of these pollutants' levels, vertical distributions and chemical transformations. A mini-MAX-DOAS instrument measured spectra at multiple viewing elevation angles in order to retrieve NO2 and SO2 differential slant column densities (dSCDs) at an Environment Canada research site north of Fort McMurray, Alberta in the fall of 2013. For the first time in the oil sands, tropospheric vertical profiles of NO2 and SO2 were retrieved by applying the optimal estimation technique to the MAX-DOAS measurements. The DOAS fit retrievals of SO2 dSCDs were validated by comparison with retrievals obtained with a quartz calibration cell with known SO2 SCD placed in front of the MAX-DOAS telescope at multiple elevation angles on a clean day. Retrieved SO2 dSCDs varied significantly from the true value depending on the chosen wavelength fitting interval. At the lowest wavelength intervals, interference by stray light and O3 differential structures significantly reduced dSCDs and caused an elevation angle dependence. These results indicate that MAX-DOAS dSCD retrieval settings, particularly for weak absorbers with differential absorption structures in low-intensity spectral regions, must be chosen carefully in order to achieve the most accurate results. Tropospheric vertical column densities (VCDs) and vertical profile retrievals of NO2, SO2 and aerosol extinction during significant pollution events will be illustrated. Trace gas vertical profiles exhibited significant variability between days and at different times of day and were often spatially

  2. Langley mobile ozone lidar: ozone and aerosol atmospheric profiling for air quality research.

    PubMed

    De Young, Russell; Carrion, William; Ganoe, Rene; Pliutau, Denis; Gronoff, Guillaume; Berkoff, Timothy; Kuang, Shi

    2017-01-20

    The Langley mobile ozone lidar (LMOL) is a mobile ground-based ozone lidar system that consists of a pulsed UV laser producing two UV wavelengths of 286 and 291 nm with energy of approximately 0.2  mJ/pulse and repetition rate of 1 kHz. The 527 nm pump laser is also transmitted for aerosol measurements. The receiver consists of a 40 cm parabolic telescope, which is used for both backscattered analog and photon counting. The lidar is very compact and highly mobile. This demonstrates the utility of very small lidar systems eventually leading to space-based ozone lidars. The lidar has been validated by numerous ozonesonde launches and has provided ozone curtain profiles from ground to approximately 4 km in support of air quality field missions.

  3. Aerosol optical properties in the ABL over arctic sea ice from airborne aerosol lidar measurements

    NASA Astrophysics Data System (ADS)

    Schmidt, Lukas; Neuber, Roland; Ritter, Christoph; Maturilli, Marion; Dethloff, Klaus; Herber, Andreas

    2014-05-01

    Between 2009 and 2013 aerosols, sea ice properties and meteorological variables were measured during several airborne campaigns covering a wide range of the western Arctic Ocean. The campaigns were carried out with the aircraft Polar 5 of the German Alfred-Wegener-Institute (AWI) during spring and summer periods. Optical properties of accumulation mode aerosol and clouds were measured with the nadir looking AMALi aerosol lidar covering the atmospheric boundary layer and the free troposphere up to 3000m, while dropsondes provided coincident vertical profiles of meteorological quantities. Based on these data we discuss the vertical distribution of aerosol backscatter in and above the atmospheric boundary layer and its dependence on relative humidity, dynamics and underlying sea ice properties. We analyze vertical profiles of lidar and coincident dropsonde measurements from various locations in the European and Canadian Arctic from spring and summer campaigns. Sea ice cover is derived from modis satellite and aircraft onboard camera images. The aerosol load in the arctic atmospheric boundary layer shows a high variability. Various meteorological parameters and in particular boundary layer properties are discussed with their respective influence on aerosol features. To investigate the effect of the frequency and size of open water patches on aerosol properties, we relate the profiles to the sea ice properties influencing the atmosphere in the upwind region.

  4. The vertical age profile in sea ice: Theory and numerical results

    NASA Astrophysics Data System (ADS)

    Lietaer, Olivier; Deleersnijder, Eric; Fichefet, Thierry; Vancoppenolle, Martin; Comblen, Richard; Bouillon, Sylvain; Legat, Vincent

    The sea ice age is an interesting diagnostic tool because it may provide a proxy for the sea ice thickness and is easier to infer from observations than the sea ice thickness. Remote sensing algorithms and modeling approaches proposed in the literature indicate significant methodological uncertainties, leading to different ice age values and physical interpretations. In this work, we focus on the vertical age distribution in sea ice. Based on the age theory developed for marine modeling, we propose a vertically-variable sea ice age definition which gives a measure of the time elapsed since the accretion of the ice particle under consideration. An analytical solution is derived from Stefan's law for a horizontally homogeneous ice layer with a periodic ice thickness seasonal cycle. Two numerical methods to solve the age equation are proposed. In the first one, the domain is discretized adaptively in space thanks to Lagrangian particles in order to capture the age profile and its discontinuities. The second one focuses on the mean age of the ice using as few degrees of freedom as possible and is based on an Arbitrary Lagrangian-Eulerian (ALE) spatial discretization and the finite element method. We observe an excellent agreement between the Lagrangian particles and the analytical solution. The mean value and the standard deviation of the finite element solution agree with the analytical solution and a linear approximation is found to represent the age profile the better, the older the ice gets. Both methods are finally applied to a stand-alone thermodynamic sea ice model of the Arctic. Computing the vertically-averaged ice age reduces by a factor of about 2 the simulated ice age compared to the oldest particle of the ice columns. A high correlation is found between the ice thickness and the age of the oldest particle. However, whether or not this will remain valid once ice dynamics is included should be investigated. In addition, the present study, based on

  5. Marli: Mars Lidar for Global Wind Profiles and Aerosol Profiles from Orbit

    NASA Technical Reports Server (NTRS)

    Abshire, J. B.; Guzewich, S. D.; Smith, M. D.; Riris, H.; Sun, X.; Gentry, B. M.; Yu, A.; Allan, G. R.

    2016-01-01

    The Mars Exploration Analysis Group's Next Orbiter Science Analysis Group (NEXSAG) has recently identified atmospheric wind measurements as one of 5 top compelling science objectives for a future Mars orbiter. To date, only isolated lander observations of martian winds exist. Winds are the key variable to understand atmospheric transport and answer fundamental questions about the three primary cycles of the martian climate: CO2, H2O, and dust. However, the direct lack of observations and imprecise and indirect inferences from temperature observations leave many basic questions about the atmospheric circulation unanswered. In addition to addressing high priority science questions, direct wind observations from orbit would help validate 3D general circulation models (GCMs) while also providing key input to atmospheric reanalyses. The dust and CO2 cycles on Mars are partially coupled and their influences on the atmospheric circulation modify the global wind field. Dust absorbs solar infrared radiation and its variable spatial distribution forces changes in the atmospheric temperature and wind fields. Thus it is important to simultaneously measure the height-resolved wind and dust profiles. MARLI provides a unique capability to observe these variables continuously, day and night, from orbit.

  6. Analytical solution for the vertical profile of daily production in the ocean

    NASA Astrophysics Data System (ADS)

    Kovač, Žarko; Platt, Trevor; Sathyendranath, Shubha; Morović, Mira

    2016-05-01

    Photosynthesis parameters are routinely estimated from in vitro measurements of primary production under constant light reaching each incubation bottle, by fitting a photosynthesis-irradiance function to the measurements. Here we take one such function and integrate it in time for variable light input, similar to natural conditions, to obtain the analytical solution for the vertical profile of daily phytoplankton production in the field. This solution is then fitted to in situ measurements of primary production profiles in the same manner as a photosynthesis-irradiance function is fitted to in vitro measurements under controlled and constant light conditions to retrieve the photosynthesis-irradiance parameters. The method is tested on the Hawaii Ocean Time-series data set. The solution explained 97.88% of the variance in measured normalized production at individual depths. The recovered parameters were then used to model the normalized daily water-column production. The model explained 99.21% of variance in normalized watercolumn production of the entire data set. The seasonal cycle of the photosynthesis parameters recovered with the analytical solution was further studied for the Hawaii Ocean Time-series. With respect to the photosynthesis parameter determination, the solution bridges the gap between classical photosynthesis-irradiance measurements under controlled light conditions and in situ measurements which are made under natural, variable light conditions. It presents a new tool for the estimation of photosynthesis parameters from in situ measurements of primary production.

  7. Structure and Evolution of Formaldehyde Vertical Profiles in the Po Valley

    NASA Astrophysics Data System (ADS)

    Kaiser, Jennifer; . Wolfe, Glenn M.; Keutsch, Frank N.; Ganzeveld, Laurens N.; Broch, Sebastian; Bohn, Birger; Fuchs, Hendrik; Gomm, Sebastian; Häseler, Rolf; Hofzumahaus, Andreas; Holland, Frank; Jäger, Julia; Lu, Keding; Li, Xin; Lohse, Insa; Rohrer, Franz; Wegener, Robert; Mentel, Thomas F.; Kiendler-Scharr, Astrid; Wahner, Andreas

    2014-05-01

    As both a source of HO2 radicals and an intermediate in the oxidation of most volatile organic compounds (VOCs), formaldehyde (HCHO) is a useful tracer for the oxidative processing of hydrocarbons that leads to the formation of secondary pollutants. During the Pan-European Gas-AeroSOls Climate Interaction Study (PEGASOS), Zeppelin-based observations allowed for high spatial and temporal mapping of HCHO throughout the planetary boundary. Here, we focus on one flight in the Po Valley in Northern Italy, where clear delineations between the nocturnal boundary layer, residual layer, and growing mixed layer are observable. Early morning profiles demonstrate an inversion in HCHO concentrations, which gradually reverses as the mixed layer develops throughout the day. In the later morning, as little as 1.4 ppb HCHO is observed in the residual layer, while 3.8 ppb HCHO is observed in the mixed layer. Preliminary analysis shows oxidized VOCs are the dominant source of HCHO throughout the planetary boundary layer. Using a 1-D box model, we further examine the role of dynamics and chemistry in the structure and evolution of HCHO vertical profiles. Acknowledgement: PEGASOS project funded by the European Commission under the Framework Programme 7 (FP7-ENV-2010-265148). Additional support provided by NSF GRFP DGE-1256259, and NSF AGS-1051338.

  8. Vertical profiles of HDO/H2O in the troposphere

    NASA Astrophysics Data System (ADS)

    Ehhalt, D. H.; Rohrer, F.; Fried, A.

    2005-07-01

    This paper reanalyzes the measurements of the D content in tropospheric water vapor by Ehhalt (1974) correcting for the isotopic contamination by wall water in the sampling tubes. The resulting corrections decrease the original D content. They are small for the data from the flights through 1967, which extended from the surface to 9 km altitude, but are large for the flights beginning 1971, which ranged from 6 to 13 km altitude and collected smaller amounts of water vapor. No correction therefore was attempted for the latter. The corrected data of the earlier flights are presented in the form of seasonally averaged profiles over Scotts Bluff, Nebraska; Death Valley, California; and the Pacific offshore of San Luis Obispo, California. As to be expected, the vertical profiles from the earlier flights show a decrease in the D content with altitude and a seasonal variation at all altitudes. However, when plotted against the water vapor mixing ratio, the D data from all seasons collapse on a line which closely follows that given by Rayleigh condensation with a fractionation factor α = 1.1, constant with altitude. These data can be explained by a simple one-dimensional convection model and the assumption that condensed water is lofted along with the water vapor.

  9. Comparing the Cloud Vertical Structure Derived from Several Methods Based on Radiosonde Profiles and Ground-based Remote Sensing Measurements

    SciTech Connect

    Costa-Suros, M.; Calbo, J.; Gonzalez, J. A.; Long, Charles N.

    2014-08-27

    The cloud vertical distribution and especially the cloud base height, which is linked to cloud type, is an important characteristic in order to describe the impact of clouds in a changing climate. In this work several methods to estimate the cloud vertical structure (CVS) based on atmospheric sounding profiles are compared, considering number and position of cloud layers, with a ground based system which is taken as a reference: the Active Remote Sensing of Clouds (ARSCL). All methods establish some conditions on the relative humidity, and differ on the use of other variables, the thresholds applied, or the vertical resolution of the profile. In this study these methods are applied to 125 radiosonde profiles acquired at the ARM Southern Great Plains site during all seasons of year 2009 and endorsed by GOES images, to confirm that the cloudiness conditions are homogeneous enough across their trajectory. The overall agreement for the methods ranges between 44-88%; four methods produce total agreements around 85%. Further tests and improvements are applied on one of these methods. In addition, we attempt to make this method suitable for low resolution vertical profiles, which could be useful in atmospheric modeling. The total agreement, even when using low resolution profiles, can be improved up to 91% if the thresholds for a moist layer to become a cloud layer are modified to minimize false negatives with the current data set, thus improving overall agreement.

  10. AROTAL Ozone and Temperature Vertical Profile Measurements from the NASA DC-8 during the SOLVE II Campaign

    NASA Technical Reports Server (NTRS)

    McGee, Thomas J.; Twigg, Laurence; Sumnicht, Grant; Hoegy, Walter; Burris, John; Silbert, Donald; Heaps, William; Neuber, R.; Trepte, C. R.

    2004-01-01

    The AROTAL instrument (Airborne Raman Ozone Temperature and Aerosol Lidar) - a collaboration between scientists at NASA Goddard Space Flight Center, and Langley Research Center - was flown on the NASA DC-8 during the SOLVE II Campaign during January and February, 2003. The flights were flown from the Arena Arctica in Kiruna, Sweden. We report measurements of temperature and ozone profiles showing approximately a 600 ppbv loss in ozone near 17.5 km, over the time frame of the aircraft campaign. Comparisons of ozone profiles from AROTAL are made with the SAGE III instrument.

  11. Assimilation of Ground-Penetrating Radar Data to Update Vertical Soil Moisture Profile

    NASA Astrophysics Data System (ADS)

    Tran, Phuong; Vanclooster, Marnik; Lambot, Sébastien

    2013-04-01

    The root zone soil moisture has been long recognized as important information for hydrological, meteorological and agricultural research. In this study, we propose a closed-loop data assimilation procedure to update the vertical soil moisture profile from time-lapse ground-penetrating radar (GPR) data. The hydrodynamic model, Hydrus-1D (Simunek et al., 2009), is used to propagate the system state in time and a radar electromagnetic model (Lambot et al., 2004) to link the state variable (soil moisture profile) with the observation data (GPR data), which enables us to update the soil moisture profile by directly assimilating the GPR data. The assimilation was performed within the maximum likelihood ensemble filter (MLEF) framework developed by Zupanski et al., (2005), for which the problem of nonlinear observation operator is solved much more effectively than the Ensemble Kalman filter (EnKF) techniques. The method estimates the optimal state as the maximum of the probability density function (PDF) instead of the minimum variance like in most of the other ensemble data assimilation methods. Direct assimilation of GPR data is a prominent advantage of our approach. It avoids solving the time-consuming inverse problem as well as the estimation errors of the soil moisture caused by inversion. In addition, instead of using only surface soil moisture, the approach allows to use the information of the whole soil moisture profile, which is reflected via the ultra wideband (UWB) GPR data, for the assimilation. The use of the UWB antenna in this study is also an advantage as it provides more information about soil moisture profile with a better depth resolution compared to other classical remote sensing techniques. Our approach was validated by a synthetic study. We constructed a synthetic soil column with a depth of 80 cm and analyzed the effects of the soil type on the data assimilation by considering 3 soil types, namely, loamy sand, silt and clay. The assimilation of GPR

  12. Vertical profiling of methane and carbon dioxide using high resolution near-infrared heterodyne spectroscopic observations

    NASA Astrophysics Data System (ADS)

    Rodin, Alexander; Klimchuk, Artem; Churbanov, Dmitry; Pereslavtseva, Anastasia; Spiridonov, Maxim; Nadezhdinskyi, Alexander

    2014-05-01

    We present new method of monitoring greenhouse gases using spectroscopic observations of solar radiation passed through the atmosphere with spectral resolution ΛvδΛ up to 108. Such a high resolution is achieved by heterodyne technique and allows to retrieve full information about spectral line shape which, in turn, is used to distinguish contribution of different atmospheric layers to the resulting absorption. Weak absorption line at 6056.5 cm-1 was selected for CO2 measurements and a quartet of lines centered at 6057 cm-1for CH4. The instrument setup includes Sun tracker with a microtelescope and chopper, diode DFB laser used as a local oscillator, a bundle of single mode optical fibers that provides medium for radiation transfer and beam coupling, reference cell with depressurized methane for LO frequency stabilization, and Fabry-Perot etalon for LO frequency calibration. A commercial p-i-n diode with squared detector replaces a mixer and IF spectrometer, providing measurement of heterodyne beating within a bandpass of few MHz, which determines the effective spectral resolution of the instrument. Spectral coverage within narrow range (about 1 cm-1) is provided by ramping the LO frequency based on feedback from the reference channel. Observations of Sun in the Moscow region have resulted for the first time in measurements of the atmospheric transmission near 1.65 μm with sub-Doppler spectral resolution. In order to retrieve vertical profiles of methane and carbon dioxide we developed the inversion algorithm implementing Tikhonov regularization approach. With measured transmission having S/N ratio of 100 or higher, the uncertainty of CH4 profile is about 10 ppb, with the uncertainty of CO2 profile at 1 ppm. This techniques is promising an affordable opportunity or widespread monitoring of greenhouse gases and may be implemented on existing ground-based stations. This work has been supported by the grant of Russian Ministry of education and science #11.G34.31.0074

  13. Vertical profiles of trapped greenhouse gases in Alaskan permafrost active layers before the spring thaw

    NASA Astrophysics Data System (ADS)

    Byun, Eunji; Yang, Ji-woong; Kim, Yongwon; Ahn, Jinho

    2015-04-01

    Seasonally frozen ground over permafrost is important in controlling annual greenhouse gas exchange between permafrost and atmosphere. Soil microbes decompose soil carbon and generate carbon dioxide and methane when they become activated. However, the actual greenhouse gas emission follows various efflux pathways. For example, seasonal freezing of the top soil layers can either restrain or press the gas emission from deeper layers. It has been reported that abrupt release of methane during spring is attributable to the emission of trapped gases that had failed to be released instantly after formation (1, 2). In order to examine the seasonally trapped greenhouse gases, we drilled five Alaskan permafrost cores before spring thaw; one from coastal tundra, two from typical boreal forests, one from area where fire occurred, and one from peat accumulated sites. Vertical profiles of carbon dioxide and methane concentrations were obtained with 5-10 cm depth intervals. We found methane peaks from two cores, indicating inhibition of methane efflux. We also analyzed organic carbon, nitrogen and water contents and compared them with the greenhouse gas profiles. We are continuing analysis for the soil temperature profiles of the sampling boreholes because the detailed temperature information might be related to microbial activity, and can be used as indirect indicators of soil water freezing and latent heat influences at some active layer depth (zero curtain effects). All the high-resolution analyses for subsurface environments may help to improve understanding greenhouse gas emission from permafrost regions. 1. Mastepanov M, et al. (2008) Large tundra methane burst during onset of freezing. Nature 456(7222):628-630. 2. Song C, et al. (2012) Large methane emission upon spring thaw from natural wetlands in the northern permafrost region. Environmental Research Letters 7(3):034009.

  14. Improvement of vertical profiles of raindrop size distribution from micro rain radar using 2D video disdrometer measurements

    NASA Astrophysics Data System (ADS)

    Adirosi, E.; Baldini, L.; Roberto, N.; Gatlin, P.; Tokay, A.

    2016-03-01

    A measurement scheme aimed at investigating precipitation properties based on collocated disdrometer and profiling instruments is used in many experimental campaigns. Raindrop size distribution (RSD) estimated by disdrometer is referred to the ground level; the collocated profiling instrument is supposed to provide complementary estimation at different heights of the precipitation column above the instruments. As part of the Special Observation Period 1 of the HyMeX (Hydrological Cycle in the Mediterranean Experiment) project, conducted between 5 September and 6 November 2012, a K-band vertically pointing micro rain radar (MRR) and a 2D video disdrometer (2DVD) were installed close to each other at a site in the historic center of Rome (Italy). The raindrop size distributions collected by 2D video disdrometer are considered to be fairly accurate within the typical sizes of drops. Vertical profiles of raindrop sizes up to 1085 m are estimated from the Doppler spectra measured by the micro rain radar with a height resolution of 35 m. Several issues related to vertical winds, attenuation correction, Doppler spectra aliasing, and range-Doppler ambiguity limit the performance of MRR in heavy precipitation or in convection, conditions that frequently occur in late summer or in autumn in Mediterranean regions. In this paper, MRR Doppler spectra are reprocessed, exploiting the 2DVD measurements at ground to estimate the effects of vertical winds at 105 m (the most reliable MRR lower height), in order to provide a better estimation of vertical profiles of raindrop size distribution from MRR spectra. Results show that the reprocessing procedure leads to a better agreement between the reflectivity computed at 105 m from the reprocessed MRR spectra and that obtained from the 2DVD data. Finally, vertical profiles of MRR-estimated RSDs and their relevant moments (namely median volume diameter and reflectivity) are presented and discussed in order to investigate the

  15. Aerosol Lidar and MODIS Satellite Comparisons for Future Aerosol Loading Forecast

    NASA Technical Reports Server (NTRS)

    DeYoung, Russell; Szykman, James; Severance, Kurt; Chu, D. Allen; Rosen, Rebecca; Al-Saadi, Jassim

    2006-01-01

    Knowledge of the concentration and distribution of atmospheric aerosols using both airborne lidar and satellite instruments is a field of active research. An aircraft based aerosol lidar has been used to study the distribution of atmospheric aerosols in the California Central Valley and eastern US coast. Concurrently, satellite aerosol retrievals, from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard the Terra and Aqua satellites, were take over the Central Valley. The MODIS Level 2 aerosol data product provides retrieved ambient aerosol optical properties (e.g., optical depth (AOD) and size distribution) globally over ocean and land at a spatial resolution of 10 km. The Central Valley topography was overlaid with MODIS AOD (5x5 sq km resolution) and the aerosol scattering vertical profiles from a lidar flight. Backward air parcel trajectories for the lidar data show that air from the Pacific and northern part of the Central Valley converge confining the aerosols to the lower valley region and below the mixed layer. Below an altitude of 1 km, the lidar aerosol and MODIS AOD exhibit good agreement. Both data sets indicate a high presence of aerosols near Bakersfield and the Tehachapi Mountains. These and other results to be presented indicate that the majority of the aerosols are below the mixed layer such that the MODIS AOD should correspond well with surface measurements. Lidar measurements will help interpret satellite AOD retrievals so that one day they can be used on a routine basis for prediction of boundary layer aerosol pollution events.

  16. Leaf morphology and photosynthetic adjustments among deciduous broad-leaved trees within the vertical canopy profile.

    PubMed

    Koike, T; Kitao, M; Maruyama, Y; Mori, S; Lei, T T

    2001-08-01

    Photosynthetic acclimation of deciduous broad-leaved tree species was studied along a vertical gradient within the canopy of a multi-species deciduous forest in northern Japan. We investigated variations in (1) local light regime and CO2 concentration ([CO2]), and (2) morphological (area, thickness and area per mass), biochemical (nitrogen and chlorophyll concentrations) and physiological (light-saturated photosynthetic rate) attributes of leaves of seven major species on three occasions (June, August and October). We studied early successional species, alder (Alnus hirsuta (Spach) Rupr.) and birch (Betula platyphylla var. japonica (Miq.) Hara); gap phase species, walnut (Juglans ailanthifolia Carrière) and ash (Fraxinus mandshurica var. japonica Rupr.); mid-successional species, basswood (Tilia japonica (Miq.) Simonk.) and elm (Ulmus davidiana var. japonica (Rehd.) Nakai); and the late-successional species, maple (Acer mono Bunge). All but maple initiated leaf unfolding from the lower part of the crown. The [CO2] within the vertical profile ranged from 320-350 ppm in the upper canopy to 405-560 ppm near the ground. The lowest and highest ambient [CO2] occurred during the day and during the night, respectively. This trend was observed consistently during the summer, but not when trees were leafless. Chlorophyll concentration was positively related to maximum photosynthetic rate within, but not among, species. Leaf senescence started from the inner part of the crown in alder and birch, but started either in the outer or top portion of the canopy of ash, basswood and maple. Chlorophyll (Chl) to nitrogen ratio in leaves increased with decreasing photon flux density. However, Chl b concentration in all species remained stable until the beginning of leaf senescence. Maximum photosynthetic rates observed in sun leaves of early successional species, gap phase or mid-successional species, and late successional species were 12.5-14.8 micromol m(-2) s(-1), 4.1-7.8 micromol

  17. Temperatures and aerosol opacities of the Mars atmosphere at aphelion: Validation and inter-comparison of limb sounding profiles from MRO/MCS and MGS/TES

    NASA Astrophysics Data System (ADS)

    Shirley, James H.; McConnochie, Timothy H.; Kass, David M.; Kleinböhl, Armin; Schofield, John T.; Heavens, Nicholas G.; McCleese, Daniel J.; Benson, Jennifer; Hinson, David P.; Bandfield, Joshua L.

    2015-05-01

    are dissimilar; TES profiles exhibit colder temperatures when TES water ice opacities are greater than those observed by MCS. Our comparisons reveal a possible systematic offset of TES and MCS temperatures at the highest altitudes resolved in the TES retrievals; TES temperatures are consistently colder than the corresponding MCS temperatures at pressures ⩽ 1 Pa (altitudes ⩾ 58 km). We otherwise find no evidence of systematic bias between TES limb sounding and MCS retrieved atmospheric quantities between 610 Pa and 1 Pa. Inter-annual variability is noted in comparisons of latitudinal temperature gradients from 55 to 70°N, in the amplitude of inversions linked with thermal tides in the middle atmosphere, and in the abundance and vertical distribution of water ice aerosols from 55 to 70°N during the aphelion season.

  18. Constraining Early Cenozoic exhumation of the British Isles with vertical profile modelling

    NASA Astrophysics Data System (ADS)

    Doepke, Daniel; Cogné, Nathan; Chew, David

    2016-04-01

    Despite decades of research is the Early Cenozoic exhumation history of Ireland and Britain still poorly understood and subject to contentious debate (e.g., Davis et al., 2012 and subsequent comments). One reason for this debate is the difficultly of constraining the evolution of onshore parts of the British Isles in both time and space. The paucity of Mesozoic and Cenozoic onshore outcrops makes direct analysis of this time span difficult. Furthermore, Ireland and Britain are situated at a passive margin, where the amount of post-rift exhumation is generally very low. Classical thermochronological tools are therefore near the edge of their resolution and make precise dating of post-rift cooling events challenging. In this study we used the established apatite fission track and (U-Th-Sm)/He techniques, but took advantage of the vertical profile approach of Gallagher et al. (2005) implemented in the QTQt modelling package (Gallagher, 2012), to better constrain the thermal histories. This method allowed us to define the geographical extent of a Late Cretaceous - Early Tertiary cooling event and to show that it was centered around the Irish Sea. Thus, we argue that this cooling event is linked to the underplating of hot material below the crust centered on the Irish Sea (Jones et al., 2002; Al-Kindi et al., 2003), and demonstrate that such conclusion would have been harder, if not impossible, to draw by modelling the samples individually without the use of the vertical profile approach. References Al-Kindi, S., White, N., Sinha, M., England, R., and Tiley, R., 2003, Crustal trace of a hot convective sheet: Geology, v. 31, no. 3, p. 207-210. Davis, M.W., White, N.J., Priestley, K.F., Baptie, B.J., and Tilmann, F.J., 2012, Crustal structure of the British Isles and its epeirogenic consequences: Geophysical Journal International, v. 190, no. 2, p. 705-725. Jones, S.M., White, N., Clarke, B.J., Rowley, E., and Gallagher, K., 2002, Present and past influence of the Iceland

  19. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    SciTech Connect

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; Zhao, C.; Cadeddu, M.

    2016-01-01

    Aerosol radiative effects and thermodynamic responses over South Asia are examined with the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of aerosol optical depths (AODs) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in northern India. The WRF-Chem model is found to heavily underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model's low bias is due to aerosol extinctions below ~2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD and extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to -0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and cloudiness) are shown to

  20. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    DOE PAGES

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; ...

    2015-06-19

    Aerosol radiative effects and thermodynamic responses over South Asia are examined with a version of the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of Aerosol Optical Depth (AOD) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in the northern India. The WRF-Chem model is found to underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model low-bias is due to aerosol extinctions below ~2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AODmore » and extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to -0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and cloudiness) are shown to respond

  1. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    SciTech Connect

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; Zhao, C.; Cadeddu, M.

    2015-06-19

    Aerosol radiative effects and thermodynamic responses over South Asia are examined with a version of the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of Aerosol Optical Depth (AOD) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in the northern India. The WRF-Chem model is found to underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model low-bias is due to aerosol extinctions below ~2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD and extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to -0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and cloudiness) are shown to respond

  2. Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

    DOE PAGES

    Feng, Y.; Kotamarthi, V. R.; Coulter, R.; ...

    2016-01-18

    Aerosol radiative effects and thermodynamic responses over South Asia are examined with the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of aerosol optical depths (AODs) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in northern India. The WRF-Chem model is found to heavily underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model's low bias is due to aerosol extinctions below  ∼  2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD and extinction profiles averaged over Southmore » Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to −0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and

  3. Aerosol Measurements by the Globally Distributed Micro Pulse Lidar Network

    NASA Technical Reports Server (NTRS)

    Spinhirne, James; Welton, Judd; Campbell, James; Berkoff, Tim; Starr, David (Technical Monitor)

    2001-01-01

    Full time measurements of the vertical distribution of aerosol are now being acquired at a number of globally distributed MP (micro pulse) lidar sites. The MP lidar systems provide full time profiling of all significant cloud and aerosol to the limit of signal attenuation from compact, eye safe instruments. There are currently eight sites in operation and over a dozen planned. At all sited there are also passive aerosol and radiation measurements supporting the lidar data. Four of the installations are at Atmospheric Radiation Measurement program sites. The network operation includes instrument operation and calibration and the processing of aerosol measurements with standard retrievals and data products from the network sites. Data products include optical thickness and extinction cross section profiles. Application of data is to supplement satellite aerosol measurements and to provide a climatology of the height distribution of aerosol. The height distribution of aerosol is important for aerosol transport and the direct scattering and absorption of shortwave radiation in the atmosphere. Current satellite and other data already provide a great amount of information on aerosol distribution, but no passive technique can adequately resolve the height profile of aerosol. The Geoscience Laser Altimeter System (GLAS) is an orbital lidar to be launched in early 2002. GLAS will provide global measurements of the height distribution of aerosol. The MP lidar network will provide ground truth and analysis support for GLAS and other NASA Earth Observing System data. The instruments, sites, calibration procedures and standard data product algorithms for the MPL network will be described.

  4. CH4 concentrations over the Amazon from GOSAT consistent with in situ vertical profile data

    NASA Astrophysics Data System (ADS)

    Webb, Alex J.; Bösch, Hartmut; Parker, Robert J.; Gatti, Luciana V.; Gloor, Emanuel; Palmer, Paul I.; Basso, Luana S.; Chipperfield, Martyn P.; Correia, Caio S. C.; Domingues, Lucas G.; Feng, Liang; Gonzi, Siegfried; Miller, John B.; Warneke, Thorsten; Wilson, Christopher

    2016-09-01

    The Amazon Basin contains large wetland ecosystems which are important sources of methane (CH4). Spaceborne observations of atmospheric CH4 can provide constraints on emissions from these remote ecosystems, but lack of validation precludes robust estimates. We present the first validation of CH4 columns in the Amazon from the Greenhouse gases Observing SATellite (GOSAT) using aircraft measurements of CH4 over five sites across the Amazon Basin. These aircraft profiles, combined with stratospheric results from the TOMCAT chemical transport model, are vertically integrated allowing direct comparison to the GOSAT XCH4 measurements (the column-averaged dry air mole fraction of CH4). The measurements agree within uncertainties or show no significant difference at three of the aircraft sites, with differences ranging from -1.9 ppb to 6.6 ppb, while at two sites GOSAT XCH4 is shown to be slightly higher than aircraft measurements, by 8.1 ppb and 9.7 ppb. The seasonality in XCH4 seen by the aircraft profiles is also well captured (correlation coefficients from 0.61 to 0.90). GOSAT observes elevated concentrations in the northwest corner of South America in the dry season and enhanced concentrations elsewhere in the Amazon Basin in the wet season, with the strongest seasonal differences coinciding with regions in Bolivia known to contain large wetlands. Our results are encouraging evidence that these GOSAT CH4 columns are generally in good agreement with in situ measurements, and understanding the magnitude of any remaining biases between the two will allow more confidence in the application of XCH4 to constrain Amazonian CH4 fluxes.

  5. Moving Toward Continuous Satellite Monitoring of PM2.5 Using the GOES Aerosol/Smoke Product (GASP) and Aircraft Profiles

    NASA Astrophysics Data System (ADS)

    Stehr, J. W.; Kondragunta, S.; Anderson, D. C.; Arkinson, H.; Brent, L. C.; Goldberg, D.; He, H.; Liaskos, C.; Ring, A.; Dickerson, R. R.; Carpenter, S.; Ciren, P.; Xu, C.

    2012-12-01

    The NOAA Geostationary Operational Environmental Satellite (GOES) makes measurements of aerosol optical depth (AOD) every 30 minutes during daylight hours. Those measurements then feed the Automated Smoke Detection and Tracking algorithm that uses fire counts, trajectory modeling and pattern recognition to identify fire plumes, especially in the western U.S. Tying these satellite measurements to surface measurements of fine particles (PM2.5) would be a considerable benefit to the air quality community and to people who live in areas with elevated fine particle concentrations. Currently, these retrievals are useful in identifying areas of elevated PM2.5 concentrations and in forecasting PM2.5 by federal, state and local agencies, but are largely limited to qualitative measures of fine particle loading. Among other issues, layers of fine particles well above ground level, cloud contamination, and particle growth by addition of water in areas of high relative humidity are examples of barriers to a direct relationship between surface PM2.5 and satellite AOD. We have identified a path forward by using aircraft profiles to determine the vertical distribution of aerosol scattering in the atmosphere. In addition, long-term measurements of scattering and rapid measurements of PM2.5 at ground-based field sites have provided a relationship between scattering and mass. Simultaneous measurements of relative humidity and temperature allow one to calculate scattering the particles would have in a dry environment and relate that to fine particle mass measurements. A relationship between rapid scattering measurements and much slower PM2.5 mass measurements is then developed, which is used to tie rapid aircraft measurements of scattering to mass. In turn, aircraft profiles are then used to tie column measurements to those at the ground and to identify cases when satellite retrievals are likely to fail. The resulting algorithm should apply throughout much of the eastern U.S., so long

  6. Vertical profiles of pollutant gases measured with passive DOAS in the Po Valley devoted to satellite and chemical model data comparison

    NASA Astrophysics Data System (ADS)

    Masieri, S.; Petritoli, A.; Kostadinov, I.; Bortoli, D.; Premuda, M.; Ravegnani, F.; Giovanelli, G.

    2009-04-01

    whose profile depends strongly on altitude [7][8]. Due to this it is also possible gain information about the atmospheric aerosol profile to set better the parameters in AMF Calculation, and then retrieve gas concentration's profiles. The NO2 concentrations measured were in the range of 0.5-25 ppb, as we expect for summer periods in rural area. GAMES (Gas Aerosol Modelling Evaluation System) model [9] was used in this work to have a reference about vertical distribution of gases (the model provides concentration profiles along 4km of altitude, with 11 growing thickness levels). Result of comparison with profile caculate by the model and profile calulate by the Multi-axis DOAS technique, is presented and then it is compared with Satellite column retrieved (with our satellite Data processor) from SCIAMACHY sensor (onboard on ENVISAT platform) and (directly NO2 Tropospheric Vertical Column provided by KNMI) from OMI (onboard on AURA platform). Good agreements between used series are shown and improvements for this methodology are discussed. One month of measurement has been taken in consideration starting from 15 May to 15 June of 2007. Vertical structure of most important trace gases calculated with model has strong correlation with the off-axis DOAS one (in some cases with R2=0,8), so better understanding of profiles and chemistry behaviour can be studied. The experience acquired within QUITSAT activity appears valuable contribution for enlargement of the DOAS applications what concern atmospheric chemistry studies, operative monitoring of the air quality over regional scale as well as satellite data validation. Deployed approaches are not restricted to NO2 but could be applied to other gases e.g. ozone, formaldehyde etc.. Key words: Off axis DOAS, NO2, CTM, AMF, gas profiles, satellite data validation, 1 2. BIBLIOGRAPHY [1] F. Evangelisti, A. Baroncelli, P. Bonasoni, G. Giovanelli, And F. Ravegnani, "Differential optical absorption spectrometer for measurement of

  7. An Investigation of Dust Aerosols and Atmospheric Profiles Associated with North Atlantic Hurricanes Using Multi-Sensor Measurements

    NASA Astrophysics Data System (ADS)

    Kamal, Mohammed Mostafa

    MODerate resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Thickness (AOT) and the Atmospheric Infrared Sounder (AIRS) atmospheric profiles (temperature and moisture) Level 2 products are studied to investigate dust aerosol impacts on hurricanes through spatial analysis for four hurricanes Isabel (2003), Frances (2004), Katrina (2005) and Helene (2006). Spatial regions were selected based on two concentric circles (an annulus) and segmented by left and right regions of 180° each around the hurricane's eye. Statistical relationships between MODIS AOT, AIRS temperature and percent relative humidity (RH) among these four hurricanes is presented. The variation of temperature and RH values represented in static-left, static-right, dynamic-left and dynamic-right for the 500 mb, 700 mb and 850 mb pressure levels were analyzed to determine the impacts of dust aerosols on temperature and RH. For the four hurricanes' average, AOT was found highest in Helene as opposed to (0.27) Isabel (0.23), Frances (0.18) and Katrina (0.16). Dust aerosols showed negative impacts on the atmospheric moisture levels and positive on the temperature. Additionally, a systematic multivariate analysis of MODIS aerosol retrievals over the North Atlantic spanning 7 hurricane seasons combined with Statistical Hurricane Intensity Prediction Scheme (SHIPS) parameters is presented. My focus is on investigating the effects of 5 categories that include aerosol, wind, relative humidity, shear, and temperature on hurricane intensities. The primary goal is to be able to explain the same physical phenomena equally well by significantly reducing the number of parameters employed in the statistical analysis. Five categories which include, wind, aerosol, shear, relative humidity, and temperature components were established by reducing 56 variables to 20. Aerosol, wind, humidity, shear, and temperature were all contributing factors in the regression equation with the ranking for the contribution found

  8. Stratospheric aerosols and climatic change

    NASA Technical Reports Server (NTRS)

    Baldwin, B.; Pollack, J. B.; Summers, A.; Toon, O. B.; Sagan, C.; Van Camp, W.

    1976-01-01

    Generated primarily by volcanic explosions, a layer of submicron silicate particles and particles made of concentrated sulfuric acids solution is present in the stratosphere. Flights through the stratosphere may be a future source of stratospheric aerosols, since the effluent from supersonic transports contains sulfurous gases (which will be converted to H2SO4) while the exhaust from Space Shuttles contains tiny aluminum oxide particles. Global heat balance calculations have shown that the stratospheric aerosols have made important contributions to some climatic changes. In the present paper, accurate radiative transfer calculations of the globally-averaged surface temperature (T) are carried out to estimate the sensitivity of the climate to changes in the number of stratospheric aerosols. The results obtained for a specified model atmosphere, including a vertical profile of the aerosols, indicate that the climate is unlikely to be affected by supersonic transports and Space Shuttles, during the next decades.

  9. Sensitivity Analysis on Fu-Liou-Gu Radiative Transfer Model for different lidar aerosol and cloud profiles

    NASA Astrophysics Data System (ADS)

    Lolli, Simone; Madonna, Fabio; Rosoldi, Marco; Pappalardo, Gelsomina; Welton, Ellsworth J.

    2016-04-01

    The aerosol and cloud impact on climate change is evaluated in terms of enhancement or reduction of the radiative energy, or heat, available in the atmosphere and at the Earth's surface, from the surface (SFC) to the Top Of the Atmosphere (TOA) covering a spectral range from the UV (extraterrestrial shortwave solar radiation) to the far-IR (outgoing terrestrial longwave radiation). Systematic Lidar network measurements from permanent observational sites across the globe are available from the beginning of this current millennium. From the retrieved lidar atmospheric extinction profiles, inputted in the Fu-Liou-Gu (FLG) Radiative Transfer code, it is possible to evaluate the net radiative effect and heating rate of the different aerosol species and clouds. Nevertheless, the lidar instruments may use different techniques (elastic lidar, Raman lidar, multi-wavelength lidar, etc) that translate into uncertainty of the lidar extinction retrieval. The goal of this study is to assess, applying a MonteCarlo technique and the FLG Radiative Transfer model, the sensitivity in calculating the net radiative effect and heating rate of aerosols and clouds for the different lidar techniques, using both synthetic and real lidar data. This sensitivity study is the first step to implement an automatic algorithm to retrieve the net radiative forcing effect of aerosols and clouds from the long records of aerosol measurements available in the frame of EARLINET and MPLNET lidar networks.

  10. Power output in vertical jumps: does optimum loading depend on activity profiles?

    PubMed

    Pazin, Nemanja; Berjan, Bobana; Nedeljkovic, Aleksandar; Markovic, Goran; Jaric, Slobodan

    2013-03-01

    The previously proposed maximum dynamic output hypothesis (MDO: i.e. the optimum load for maximizing the power output during jumping is one's own body) was tested on individuals of various activity profiles. Forty males (10 strength-trained athletes, 10 speed-trained athletes, 10 physically active non-athletes, and 10 sedentary individuals) performed different vertical jumps on a force plate while a pulley system was used to either reduce or increase the subject's body weight by 10-30 %. As expected, an increase in external loading resulted in a significant increase (p < 0.001) in force output and a concomitant decrease of peak jumping velocity in all groups of participants. The main finding, however, was that all groups revealed the maximum peak and mean power output at approximately the subjects' own body weight although their weight represented prominently different percentage of their maximum dynamic strength. While a significant (p < 0.05), albeit moderate, 'group × load' interaction in one jump was observed for the peak power output, the individual optimum load for maximizing the power output number did not differ among the groups. Although apparently further research on various types of movements is needed, the present results provide, so far, the strongest support of the MDO hypothesis.

  11. Numerical simulation of advection fog formation on multi-disperse aerosols due to combustion-related pollutants

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Liaw, G. S.

    1980-01-01

    The effects of multi-disperse distribution of the aerosol population are presented. Single component and multi-component aerosol species on the condensation/nucleation processes which affect the reduction in visibility are described. The aerosol population with a high particle concentration provided more favorable conditions for the formation of a denser fog than the aerosol population with a greater particle size distribution when the value of the mass concentration of the aerosols was kept constant. The results were used as numerical predictions of fog formation. Two dimensional observations in horizontal and vertical coordinates, together with time-dependent measurements were needed as initial values for the following physical parameters: (1)wind profiles; (2) temperature profiles; (3) humidity profiles; (4) mass concentration of aerosol particles; (5) particle size distribution of aerosols; and (6) chemical composition of aerosols. Formation and dissipation of advection fog, thus, can be forecasted numerically by introducing initial values obtained from the observations.

  12. Boundary Layer Observations of Water Vapor and Aerosol Profiles with an Eye-Safe Micro-Pulse Differential Absorption Lidar (DIAL)

    NASA Astrophysics Data System (ADS)

    Nehrir, A. R.; Repasky, K. S.; Carlsten, J.; Ismail, S.

    2011-12-01

    Measurements of real-time high spatial and temporal resolution profiles of combined water vapor and aerosols in the boundary layer 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 aerosol 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

  13. Aerosol dynamics above the water area of the Peter the Great Bay during the dust storm in the Gobi desert

    NASA Astrophysics Data System (ADS)

    Bukin, O. A.; Pavlov, A. N.; Kulchin, J. N.; Shmirko, K. A.; Salyuk, P. A.; Stoluarchuk, S. Y.

    2006-11-01

    This article presents aerosol dynamic monitoring over the Peter the Great bay during dust storms in continental areas of the China and Mongolia. Both satellite and lidar data was analyzed. Vertical profiles of aerosol backscattering coefficient and aerosol optical thickness were calculated. Aerosol optical thickness in different layers were retrieved and compared with the satellite ones. Correlation coefficient between satellite and lidar data was calculated. Aerosol layer location was compared to Brent-Vaisal criterion of stability. Aerosol layer stratification during spring - summer (April - June 2006) period was analyzed.

  14. Ground-based Measurements of Vertical Profiles and Columns of Atmospheric Trace Gases Over Toronto Using a New High-Resolution Fourier Transform Infrared Spectrometer

    NASA Astrophysics Data System (ADS)

    Wiacek, A.; Yashcov, D.; Strong, K.; Boudreau, L.; Rochette, L.; Roy, C.

    2002-12-01

    The University of Toronto Atmospheric Observatory (TAO) has recently been established at Toronto, Canada. TAO includes several instruments, with a DA8 Fourier Transform Spectrometer (DA8 FTS, manufactured by ABB Bomem Inc., Québec, Canada) serving as the primary instrument at the facility. The geographic position of TAO (43.66°N, 79.40°W) makes it well suited for long-term measurements of mid-latitude stratospheric ozone and related species, while its urban setting enables measurements of tropospheric pollution. The DA8 FTS is based on a Michelson interferometer with a maximum optical path difference of 250 cm, providing a maximum unapodized resolution of 0.0026 cm-1. It is currently equipped with KBr and CaF2 beamsplitters, and InSb and HgCdTe detectors, for coverage of the spectral range from 700 to 4100 cm-1. A new heliostat (manufactured by Aim Controls Inc., California, USA) provides active solar tracking, collecting the incoming solar radiation and directing it into the FTS. The TAO DA8 FTS incorporates a new optical design recently developed by ABB Bomem Inc., which results in a fixed optical axis through the beamsplitter (and a fixed focal point on the detector) as well as a more stable modulation efficiency. The new instrument optics will be discussed. Next, the performance of the instrument will be examined in the context of standard NDSC (Network for the Detection of Stratospheric Change) trace gas column and vertical profile retrieval techniques, which use least squares fitting algorithms (SFIT, SFIT2). TAO has been operational (weather permitting) since October 2001. We have been retrieving columns and vertical profiles of HCl, HF, CH4, OCS, C2H6, CO, N2O and NO2 since May 2002. A detailed error analysis of retrieved columns and vertical profiles has been undertaken for the above species. Future plans for the TAO FTS include comparing our measurements with satellite measurements made by MOPITT, OSIRIS, and the upcoming ACE and MAESTRO instruments

  15. Ensemble-Based Assimilation of Aerosol Observations in GEOS-5

    NASA Technical Reports Server (NTRS)

    Buchard, V.; Da Silva, A.

    2016-01-01

    MERRA-2 is the latest Aerosol Reanalysis produced at NASA's Global Modeling Assimilation Office (GMAO) from 1979 to present. This reanalysis is based on a version of the GEOS-5 model radiatively coupled to GOCART aerosols and includes assimilation of bias corrected Aerosol Optical Depth (AOD) from AVHRR over ocean, MODIS sensors on both Terra and Aqua satellites, MISR over bright surfaces and AERONET data. In order to assimilate lidar profiles of aerosols, we are updating the aerosol component of our assimilation system to an Ensemble Kalman Filter (EnKF) type of scheme using ensembles generated routinely by the meteorological assimilation. Following the work performed with the first NASA's aerosol reanalysis (MERRAero), we first validate the vertical structure of MERRA-2 aerosol assimilated fields using CALIOP data over regions of particular interest during 2008.

  16. Aerosol Profile Measurements from the NASA Langley Research Center Airborne High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Obland, Michael D.; Hostetler, Chris A.; Ferrare, Richard A.; Hair, John W.; Roers, Raymond R.; Burton, Sharon P.; Cook, Anthony L.; Harper, David B.

    2008-01-01

    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- Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite mission, aerosol property retrievals combining passive and active instrument measurements, aerosol type identification, aerosol-cloud interactions, and cloud top and planetary boundary layer (PBL) height determinations. Measurements and lessons learned from the HSRL are leading towards next-generation HSRL instrument designs that will enable even further studies of aerosol intensive and extensive parameters and the effects of aerosols on the climate system. This paper will highlight several of the areas in which the NASA Airborne HSRL is making contributions to climate science.

  17. Demonstration of Aerosol Property Profiling by Multiwavelength Lidar Under Varying Relative Humidity Conditions

    NASA Technical Reports Server (NTRS)

    Veselovskii, I.; Whiteman, D. N.; Kolgotin, A.; Andrews, E.; Korenskii, M.

    2009-01-01

    During the months of July-August 2007 NASA conducted a research campaign called the Tropical Composition, Clouds and Climate Coupling (TC4) experiment. Vertical profiles of ozone were measured daily using an instrument known as an ozonesonde, which is attached to a weather balloon and launch to altitudes in excess of 30 km. These ozone profiles were measured over coastal Las Tablas, Panama (7.8N, 80W) and several times per week at Alajuela, Costa Rica (ION, 84W). Meteorological systems in the form of waves, detected most prominently in 100-300 in thick ozone layer in the tropical tropopause layer, occurred in 50% (Las Tablas) and 40% (Alajuela) of the soundings. These layers, associated with vertical displacements and classified as gravity waves ("GW," possibly Kelvin waves), occur with similar stricture and frequency over the Paramaribo (5.8N, 55W) and San Cristobal (0.925, 90W) sites of the Southern Hemisphere Additional Ozonesondes (SHADOZ) network. The gravity wave labeled layers in individual soundings correspond to cloud outflow as indicated by the tracers measured from the NASA DC-8 and other aircraft data, confirming convective initiation of equatorial waves. Layers representing quasi-horizontal displacements, referred to as Rossby waves, are robust features in soundings from 23 July to 5 August. The features associated with Rossby waves correspond to extra-tropical influence, possibly stratospheric, and sometimes to pollution transport. Comparison of Las Tablas and Alajuela ozone budgets with 1999-2007 Paramaribo and San Cristobal soundings shows that TC4 is typical of climatology for the equatorial Americas. Overall during TC4, convection and associated meteorological waves appear to dominate ozone transport in the tropical tropopause layer.

  18. SAM II aerosol profile measurements, Poker Flat, Alaska; July 16-19, 1979

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Chu, W. P.; Mcmaster, L. R.; Grams, G. W.; Herman, B. M.; Pepin, T. J.; Russell, P. B.; Swissler, T. J.

    1981-01-01

    SAM II satellite measurements during the July 1979 Poker Flat mission, yielded an aerosol extinction coefficient of 0.0004/km at 1.0 micron wavelength, in the region of the stratospheric aerosol mixing ratio peak (12-16 km). The stratospheric aerosol optical depth for these data, calculated from the tropopause through 30 km, is approximately 0.001. These results are consistent with the average 1979 summertime values found throughout the Arctic.

  19. Cloud and Aerosol Properties, Precipitable Water, and Profiles of Temperature and Water Vapor from MODIS

    NASA Technical Reports Server (NTRS)

    King, Michael D.; Menzel, W. Paul; Kaufman, Yoram J.; Tanre, Didier; Gao, Bo-Cai; Platnick, Steven; Ackerman, Steven A.; Remer, Lorraine A.; Pincus, Robert; Hubanks, Paul A.

    2003-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) is an earth-viewing sensor that flies on the Earth Observing System (EOS) Terra and Aqua satellites, launched in 1999 and 2002, respectively. MODIS scans a swath width of 2330 km that is sufficiently wide to provide nearly complete global coverage every two days from a polar-orbiting, sun-synchronous, platform at an altitude of 705 km. MODIS provides images in 36 spectral bands between 0.415 and 14.235 pm with spatial resolutions of 250 m (2 bands), 500 m (5 bands) and 1000 m (29 bands). These bands have been carefully selected to en- able advanced studies of land, ocean, and atmospheric properties. Twenty-six bands are used to derive atmospheric properties such as cloud mask, atmospheric profiles, aerosol properties, total precipitable water, and cloud properties. In this paper we describe each of these atmospheric data products, including characteristics of each of these products such as file size, spatial resolution used in producing the product, and data availability.

  20. LASE measurements of water vapor and aerosol profiles during the Plains Elevated Convection at Night (PECAN) field experiment

    NASA Astrophysics Data System (ADS)

    Nehrir, A. R.; Ferrare, R. A.; Kooi, S. A.; Butler, C. F.; Notari, A.; Hair, J. W.; Collins, J. E., Jr.; Ismail, S.

    2015-12-01

    The Lidar Atmospheric Sensing Experiment (LASE) system was deployed on the NASA DC-8 aircraft during the Plains Elevated Convection At Night (PECAN) field experiment, which was conducted during June-July 2015 over the central and southern plains. LASE is an active remote sensor that employs the differential absorption lidar (DIAL) technique to measure range resolved profiles of water vapor and aerosols above and below the aircraft. The DC-8 conducted nine local science flights from June 30- July 14 where LASE sampled water vapor and aerosol fields in support of the PECAN primary science objectives relating to better understanding nocturnal Mesoscale Convective Systems (MCSs), Convective Initiation (CI), the Low Level Jet (LLJ), bores, and to compare different airborne and ground based measurements. LASE observed large spatial and temporal variability in water vapor and aerosol distributions in advance of nocturnal MCSs, across bores resulting from MCS outflow boundaries, and across the LLJ associated with the development of MCSs and CI. An overview of the LASE data collected during the PECAN field experiment will be presented where emphasis will be placed on variability of water vapor profiles in the vicinity of severe storms and intense convection in the central and southern plains. Preliminary comparisons show good agreement between coincident LASE and radiosonde water vapor profiles. In addition, an advanced water vapor DIAL system being developed at NASA Langley will be discussed.

  1. Application of a new vertical profiling tool (ESASS) for sampling groundwater quality during hollow-stem auger drilling

    USGS Publications Warehouse

    Harte, P.T.; Flanagan, S.M.

    2011-01-01

    A new tool called ESASS (Enhanced Screen Auger Sampling System) was developed by the U.S. Geological Survey. The use of ESASS, because of its unique U.S. patent design (U.S. patent no. 7,631,705 B1), allows for the collection of representative, depth-specific groundwater samples (vertical profiling) in a quick and efficient manner using a 0.305-m long screen auger during hollow-stem auger drilling. With ESASS, the water column in the flights above the screen auger is separated from the water in the screen auger by a specially designed removable plug and collar. The tool fits inside an auger of standard inner diameter (82.55 mm). The novel design of the system constituted by the plug, collar, and A-rod allows the plug to be retrieved using conventional drilling A-rods. After retrieval, standard-diameter (50.8 mm) observation wells can be installed within the hollow-stem augers. Testing of ESASS was conducted at one waste-disposal site with tetrachloroethylene (PCE) contamination and at two reference sites with no known waste-disposal history. All three sites have similar geology and are underlain by glacial, stratified-drift deposits. For the applications tested, ESASS proved to be a useful tool in vertical profiling of groundwater quality. At the waste site, PCE concentrations measured with ESASS profiling at several depths were comparable (relative percent difference <25%) to PCE concentrations sampled from wells. Vertical profiling with ESASS at the reference sites illustrated the vertical resolution achievable in the profile system; shallow groundwater quality varied by a factor of five in concentration of some constituents (nitrate and nitrite) over short (0.61 m) distances. Ground Water Monitoring & Remediation ?? 2011, National Ground Water Association. No claim to original US government works.

  2. Application of a new vertical profiling tool (ESASS) for sampling groundwater quality during hollow-stem auger drilling

    USGS Publications Warehouse

    Harte, Philip T.; Flanagan, Sarah M.

    2011-01-01

    A new tool called ESASS (Enhanced Screen Auger Sampling System) was developed by the U.S. Geological Survey. The use of ESASS, because of its unique U.S. patent design (U.S. patent no. 7,631,705 B1), allows for the collection of representative, depth-specific groundwater samples (vertical profiling) in a quick and efficient manner using a 0.305-m long screen auger during hollow-stem auger drilling. With ESASS, the water column in the flights above the screen auger is separated from the water in the screen auger by a specially designed removable plug and collar. The tool fits inside an auger of standard inner diameter (82.55 mm). The novel design of the system constituted by the plug, collar, and A-rod allows the plug to be retrieved using conventional drilling A-rods. After retrieval, standard-diameter (50.8 mm) observation wells can be installed within the hollow-stem augers. Testing of ESASS was conducted at one waste-disposal site with tetrachloroethylene (PCE) contamination and at two reference sites with no known waste-disposal history. All three sites have similar geology and are underlain by glacial, stratified-drift deposits. For the applications tested, ESASS proved to be a useful tool in vertical profiling of groundwater quality. At the waste site, PCE concentrations measured with ESASS profiling at several depths were comparable (relative percent difference <25%) to PCE concentrations sampled from wells. Vertical profiling with ESASS at the reference sites illustrated the vertical resolution achievable in the profile system; shallow groundwater quality varied by a factor of five in concentration of some constituents (nitrate and nitrite) over short (0.61 m) distances.

  3. Vertical profile and components of marine planktonic archaea in the Pacific sector of the Arctic Oceean

    NASA Astrophysics Data System (ADS)

    Akiyama, S.; Amano (Sato), C.; Uchida, M.; Utsumi, M.

    2011-12-01

    Ocean was carried out during a cruise, with R/V Mirai from September to October 2008 (MR08-04). We focused on 3 stations located in Mendeleyev Ridge, Northwind Ridge and Canada Basin. CARD-FISH and clone library techniques targeted on archaeal specific 16S rRNA gene were used to investigate vertical profile of marine planktonic archaeal abundance and characterize their community structure. The results showed that their community structure comprised Group I Crenarchaeota, Group II, III and IV Euryarchaeota. Group I Crenarchaeota outnumbered Group II Euryarchaeota through the water column (0.0064-2.5 x 104 and 0.0038-1.3 x 104 cells/mL, respectively). Although their abundance decreased exponentially with depth, Group I Crenarchaeota relative abundance of the toltal bacteria were high in > 200 m depth at all station. Besides, Group III Euryarchaeota sequences were more frequently detected than other oceans (24 of 115 sequences; 20.9%). It could be said that Group III Euryarchaeota is more predominant in this ocean. Moreover, it was observed that vertical profile of their abundance and components were different depending on the stations and depth.

  4. Interpretation of MODIS Cloud Images by CloudSat/CALIPSO Cloud Vertical Profiles

    NASA Astrophysics Data System (ADS)

    Wang, T.; Fetzer, E. J.; Wong, S.; Yue, Q.

    2015-12-01

    Clouds observed by passive remote-sensing imager (Aqua-MODIS) are collocated to cloud vertical profiles observed by active profiling sensors (CloudSat radar and CALIPSO lidar) at the pixel-scale. By comparing different layers of cloud types classified in the 2B-CLDCLASS-LIDAR product from CloudSat+CALIPSO to those cloud properties observed by MODIS, we evaluate the occurrence frequencies of cloud types and cloud-overlap in CloudSat+CALIPSO for each MODIS cloud regime defined by cloud optical depth (τ) and cloud-top pressure (P) histograms. We find that about 70% of MODIS clear sky agrees with the clear category in CloudSat+CALIPSO; whereas the remainder is either single layer (~25%) cirrus (Ci), low-level cumulus (Cu), stratocumulus (Sc), or multi-layer (<5%) clouds in CloudSat+CALIPSO. Under MODIS cloudy conditions, 60%, 28%, and 8% of the occurrences show single-, double-, and triple-layer clouds, respectively in CloudSat+CALIPSO. When MODIS identifies single-layer clouds, 50-60% of the MODIS low-level clouds are categorized as stratus (Sc) in CloudSat+CALIPSO. Over the tropics, ~70% of MODIS high and optically thin clouds (considered as cirrus in the histogram) is also identified as Ci in CloudSat+CALIPSO, and ~40% of MODIS high and optically thick clouds (considered as convective in the histogram) agrees with CloudSat+CALIPSO deep convections (DC). Over mid-latitudes these numbers drop to 45% and 10%, respectively. The best agreement occurs in tropical single-layer cloud regimes, where 90% of MODIS high-thin clouds are identified as Ci by CloudSat+CALIPSO and 60% of MODIS high-thick clouds are identified as DC. Worst agreement is found for multi-layer clouds, where cirrus on top of low- and mid-level clouds in MODIS are frequently categorized as high-thick clouds by passive imaging - among these only 5-12% are DC in CloudSat+CALIPSO. It is encouraging that both MODIS low-level clouds (regardless of optical thickness) and high-level thin clouds are consistently

  5. The effective aerosol attenuation on determination error of ocean and atmosphere temperatures by remote methods

    NASA Technical Reports Server (NTRS)

    1978-01-01

    This article contains a survey of literature on errors in establishing temperature of the underlying surface and the vertical profile of temperature in the 15 microns CO2 band when aerosol attenuation was not taken into account. Experimental data show the large contribution of the aerosol to total radiation attentuation. Evaluations are made of the relationship of the magnitude of establishment error to location and optical thickness of the aerosol layer.

  6. Development of a Ground-Based Differential Absorption Lidar for High Accurate Measurements of Vertical CO2 Concentration Profiles

    NASA Astrophysics Data System (ADS)

    Nagasawa, Chikao; Abo, Makoto; Shibata, Yasukuni; Nagai, Tomohiro; Nakazato, Masahisa; Sakai, Tetsu; Tsukamoto, Makoto; Sakaizawa, Daisuku

    2010-05-01

    High-accurate vertical carbon dioxide (CO2) profiles are highly desirable in the inverse method to improve quantification and understanding of the global sink and source of CO2, and also global climate change. We have developed a ground based 1.6μm differential absorption lidar (DIAL) to achieve high accurate measurements of vertical CO2 profiles in the atmosphere. The DIAL system is constructed from the optical parametric oscillation(OPO) transmitter and the direct detection receiving system that included a near-infrared photomultiplier tube operating at photon counting mode. The primitive DIAL measurement was achieved successfully the vertical CO2 profile up to 7 km altitude with an error less than 1.0 % by integration time of 50 minutes and vertical resolution of 150m. We are developing the next generation 1.6 μm DIAL that can measure simultaneously the vertical CO2 concentration, temperature and pressure profiles in the atmosphere. The output laser of the OPO is 20mJ at a 500 Hz repetition rate and a 600mm diameter telescope is employed for this measurement. A very narrow interference filter (0.5nm FWHM) is used for daytime measurement. As the spectra of absorption lines of any molecules are influenced basically by the temperature and pressure in the atmosphere, it is important to measure them simultaneously so that the better accuracy of the DIAL measurement may be realized. Moreover, the value of the retrieved CO2 concentration will be improved remarkably by processing the iteration assignment of CO2 concentration, temperature and pressure, which measured by DIAL techniques. This work was financially supported by the Japan EOS Promotion Program by the MEXT Japan and System Development Program for Advanced Measurement and Analysis by the JST. Reference D. Sakaizawa, C. Nagasawa, T. Nagai, M. Abo, Y. Shibata, H. Nagai, M. Nakazato, and T. Sakai, Development of a 1.6μm differential absorption lidar with a quasi-phase-matching optical parametric oscillator and

  7. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    DOE PAGES

    Debnath, Mithu; Iungo, G. Valerio; Ashton, Ryan; ...

    2017-02-06

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with goodmore » accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.« less

  8. EFFECTS OF NITROGEN PHOTOABSORPTION CROSS SECTION RESOLUTION ON MINOR SPECIES VERTICAL PROFILES IN TITAN’S UPPER ATMOSPHERE

    SciTech Connect

    Luspay-Kuti, A.; Mandt, K. E.; Greathouse, T. K.; Plessis, S.

    2015-03-01

    The significant variations in both measured and modeled densities of minor species in Titan’s atmosphere call for the evaluation of possible influencing factors in photochemical modeling. The effect of nitrogen photoabsorption cross section selection on the modeled vertical profiles of minor species is analyzed here, with particular focus on C{sub 2}H{sub 6} and HCN. Our results show a clear impact of cross sections used on all neutral and ion species studied. Affected species include neutrals and ions that are not primary photochemical products, including species that do not even contain nitrogen. The results indicate that photochemical models that employ low-resolution cross sections may significantly miscalculate the vertical profiles of minor species. Such differences are expected to have important implications for Titan’s overall atmospheric structure and chemistry.

  9. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    SciTech Connect

    Debnath, Mithu; Iungo, G. Valerio; Ashton, Ryan; Brewer, W. Alan; Choukulkar, Aditya; Delgado, Ruben; Lundquist, Julie K.; Shaw, William J.; Wilczak, James M.; Wolfe, Daniel

    2017-01-01

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with good accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.

  10. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    NASA Astrophysics Data System (ADS)

    Debnath, Mithu; Valerio Iungo, G.; Ashton, Ryan; Brewer, W. Alan; Choukulkar, Aditya; Delgado, Ruben; Lundquist, Julie K.; Shaw, William J.; Wilczak, James M.; Wolfe, Daniel

    2017-02-01

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with good accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.

  11. Aerosol Best Estimate Value-Added Product

    SciTech Connect

    Flynn, C; Turner, D; Koontz, A; Chand, D; Sivaraman, C

    2012-07-19

    The objective of the Aerosol Best Estimate (AEROSOLBE) value-added product (VAP) is to provide vertical profiles of aerosol extinction, single scatter albedo, asymmetry parameter, and Angstroem exponents for the atmospheric column above the Central Facility at the ARM Southern Great Plains (SGP) site. We expect that AEROSOLBE will provide nearly continuous estimates of aerosol optical properties under a range of conditions (clear, broken clouds, overcast clouds, etc.). The primary requirement of this VAP was to provide an aerosol data set as continuous as possible in both time and height for the Broadband Heating Rate Profile (BBHRP) VAP in order to provide a structure for the comprehensive assessment of our ability to model atmospheric radiative transfer for all conditions. Even though BBHRP has been completed, AEROSOLBE results are very valuable for environmental, atmospheric, and climate research.

  12. Local fluctuations of ozone from 16 km to 45 km deduced from in situ vertical ozone profile

    NASA Technical Reports Server (NTRS)

    Moreau, G.; Robert, C.

    1994-01-01

    A vertical ozone profile obtained by an in situ ozone sonde from 16 km to 45 km, has allowed to observe local ozone concentration variations. These variations can be observed, thanks to a fast measurement system based on a UV absorption KrF excimer laser beam in a multipass cell. Ozone standard deviation versus altitude calculated from the mean is derived. Ozone variations or fluctuations are correlated with the different dynamic zones of the stratosphere.

  13. Vertical profiles of ozone, VOCs and meteorological parameters in within and outside of Mexico City during the MILAGRO field Campaign

    NASA Astrophysics Data System (ADS)

    Marquez, C.; Greenberg, J.; Bueno, E.; Bernabe, R.; Aguilar, J.; Blanco, S.; Wöhrnschimmel, H.; Guenther, A.; Cardenas, B.; Turnipseed, A.

    2007-05-01

    High ozone levels with maxima over 250 ppb have been an air quality problem in Mexico City for more than a decade. This ozone is produced in the daytime by photochemical reactions, initiated by its precursors, nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of solar ultraviolet radiation. The objective of this work is to contribute to the understanding of the evolution of these air pollutants at different heights of the boundary layer by means of vertical profile measurements. Ozone, VOCs and meteorological vertical profiles were determined in Northern Mexico City (T0 site) using a tethered balloon for 10 days during the MILAGRO field Campaign 2006, between 4 AM and 4 PM. Measurements were done up to 1000 meter above ground (ozone and meteorological parameters) and up to 200 m above ground for VOCs. VOCs samples were collected during 4 minutes in canisters and analyzed with GC-FID to identify 13 species (ethane, propane, propylene, butane, acetylene, pentane, hexane, heptane, benzene, octane, toluene, nonane and o-xylene). For 4 of the days, VOC integrated samples were also taken using personal pumps and absorbent cartridges at height between 200 and 1000 m. Sample cartridges were analyzed by GC-MS for volatile organic compounds (n-butane, i-pentane, n- pentane, benzene, toluene, ethyl-benzene, o-xylene, m&p-xylene, 1,2,4-tri-methyl-benzene and C3-benzenes). Ozone vertical profiles, frequently presented high concentrations above 400 m in the early morning. During the daytime, more homogeneous profiles indicate an increased vertical mixing. VOCs profiles show similar concentrations for all heights at dawn. In the morning, highest concentrations were determined at a height of about 100 meter, whereas at noon and in the afternoon concentrations decreased with height. Comparing VOC concentrations during the course of a day, highest values are measured in the morning. The highest VOC concentrations were propane, butane, and toluene. For some

  14. Vertical profiles of ozone, water vapor and meteorological parameters and boundary-layer conditions at Summit, Greenland during June 2000

    NASA Astrophysics Data System (ADS)

    Helmig, D.; Alfieri, J. G.; Alfieri, J. G.; Boulter, J.; Boulter, J.; David, D.; Birks, J.; Cullen, N.; Cullen, N.; Steffen, K.; Steffen, K.; Johnson, B.; Oltmans, S.

    2001-12-01

    The temporal and spatial distribution of boundary-layer ozone was studied during June 2000 at Summit, Greenland by surface-level measurements and vertical profiling from a tethered balloon. Three weeks of continuous ozone surface data and 133 meteorological and 82 ozone vertical profile data sets were collected from the surface to a maximum altitude of 1400 m above ground. The lower atmosphere at Summit was characterized by the prevalence of high stability conditions with strong surface temperature inversions. These inversions succumbed to neutral to slightly unstable conditions between appr. 9.00 and 18.00 hrs local time with the formation of shallow mixing heights of typically 70-250 m above the surface. Surface ozone ranged from 39 to 68 ppbv and occasionally had rapid changes of up to 20 ppb in 12 hours. The diurnal mean ozone mixing ratio showed distinct cycles indicating meteorological and photochemical controls of surface ozone. Vertical profiles were within the range of 37 to 76 ppb and showed strong stratification in the lower troposphere. A high correlation of high ozone/low water vapor indicated the transport of high tropospheric/low stratospheric air into the lower boundary layer. An appr. 1 to 4 ppb decline of ozone towards the surface was frequently observed within the neutrally stable mixed layer during midday hours. These observations suggest that the boundary-layer ozone and ozone depletion/deposition to the snowpack are influenced by photochemical processes that follow diurnal dependencies.

  15. Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds

    SciTech Connect

    Turner, David, D.; Ferrare, Richard, A.

    2011-07-06

    The 'Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds' project focused extensively on the analysis and utilization of water vapor and aerosol profiles derived from the ARM Raman lidar at the Southern Great Plains ARM site. A wide range of different tasks were performed during this project, all of which improved quality of the data products derived from the lidar or advanced the understanding of atmospheric processes over the site. These activities included: upgrading the Raman lidar to improve its sensitivity; participating in field experiments to validate the lidar aerosol and water vapor retrievals; using the lidar aerosol profiles to evaluate the accuracy of the vertical distribution of aerosols in global aerosol model simulations; examining the correlation between relative humidity and aerosol extinction, and how these change, due to horizontal distance away from cumulus clouds; inferring boundary layer turbulence structure in convective boundary layers from the high-time-resolution lidar water vapor measurements; retrieving cumulus entrainment rates in boundary layer cumulus clouds; and participating in a field experiment that provided data to help validate both the entrainment rate retrievals and the turbulent profiles derived from lidar observations.

  16. Aerosol Optical Properties Measured Onboard the Ronald H. Brown During ACE Asia as a Function of Aerosol Chemical Composition and Source Region

    NASA Technical Reports Server (NTRS)

    Quinn, P. K.; Coffman, D. J.; Bates, T. S.; Welton, E. J.; Covert, D. S.; Miller, T. L.; Johnson, J. E.; Maria, S.; Russell, L.; Arimoto, R.

    2004-01-01

    During the ACE Asia intensive field campaign conducted in the spring of 2001 aerosol properties were measured onboard the R/V Ronald H. Brown to study the effects of the Asian aerosol on atmospheric chemistry and climate in downwind regions. Aerosol properties measured in the marine boundary layer included chemical composition; number size distribution; and light scattering, hemispheric backscattering, and absorption coefficients. In addition, optical depth and vertical profiles of aerosol 180 deg backscatter were measured. Aerosol within the ACE Asia study region was found to be a complex mixture resulting from marine, pollution, volcanic, and dust sources. Presented here as a function of air mass source region are the mass fractions of the dominant aerosol chemical components, the fraction of the scattering measured at the surface due to each component, mass scattering efficiencies of the individual components, aerosol scattering and absorption coefficients, single scattering albedo, Angstrom exponents, optical depth, and vertical profiles of aerosol extinction. All results except aerosol optical depth and the vertical profiles of aerosol extinction are reported at a relative humidity of 55 +/- 5%. An over-determined data set was collected so that measured and calculated aerosol properties could be compared, internal consistency in the data set could be assessed, and sources of uncertainty could be identified. By taking into account non-sphericity of the dust aerosol, calculated and measured aerosol mass and scattering coefficients agreed within overall experimental uncertainties. Differences between measured and calculated aerosol absorption coefficients were not within reasonable uncertainty limits, however, and may indicate the inability of Mie theory and the assumption of internally mixed homogeneous spheres to predict absorption by the ACE Asia aerosol. Mass scattering efficiencies of non-sea salt sulfate aerosol, sea salt, submicron particulate organic

  17. Development and application of lightweight instruments for vertical profiling of ozone and carbon monoxide

    NASA Astrophysics Data System (ADS)

    Bognar, John Andrew

    1998-09-01

    This thesis covers the development of low cost, lightweight instrumentation for vertical profiling measurements of ozone and carbon monoxide in the troposphere. These instruments are designed to fly on small, low-payload airborne platforms such as tethered kites and blimps. Thus, they can be used for making measurements from light aircraft as well. Due to their small size and low cost, they are also suitable for use as disposable sondes on released balloons or in dropsondes. The design and test results of a simple single-beam ultraviolet photometer for ozone measurements are presented. A novel airflow system and advanced electronics are among the most important changes from earlier reported systems. The current version of the instrument fits into a package 8 x 8 x 40 cm, weighs under 0.5 kg, and consumes approximately 8 watts of power. Independent measurements of ozone are made every six seconds, with a sensitivity of 0.3 ppbv ozone and a precision of 2%. The design and test results of a simple carbon monoxide detector based on the reducing gas detector principle are also presented. It operates by reacting carbon monoxide with mercuric oxide to produce mercury vapor, which may then be measured via ultraviolet absorption to compute the concentration of carbon monoxide. This instrument has several features which distinguish it from similar carbon monoxide analyzers, all of which contribute to its usefulness on small airborne platforms. It fits a package 10 x 20 x 25 cm, has a mass of 2.0 kg, and consumes an average of 20 watts of power. An independent measurement of carbon monoxide is made every eight seconds, with a sensitivity of 3 ppbv carbon monoxide and a precision of 4%. The packages these instruments are flown in are described, and other associated instruments in the packages are briefly covered. Two major packages are described: one for kites and blimps, and the other for light aircraft. These packages, while having a similar design architecture, have some

  18. How does the Vertical Profile of Baroclinicity Affect the Wave Instability?

    NASA Astrophysics Data System (ADS)

    Iwasaki, T.; Kodama, C.

    2011-12-01

    The global warming is expected to decrease the baroclinicity in the lower troposphere but increase it in the upper troposphere. It is unknown how the vertical profile of baroclinicity affects the wave instability. In order to study this problem, the growth rate of instability waves is generalized to consider the realistic atmosphere on the basis of wave-mean flow interactions in the mass-weighted isentropic zonal mean (MIM). Energy conversion diagram in MIM becomes a cascade type, which is different from the four box scheme in the conventional Eurelian mean framework. The wave energy W is converted from the zonal mean kinetic energy Kz and the integrated conversion rate is proportional to the mean zonal flow difference between the Eliassen-Palm (E-P) flux convergence and divergence areas. The space-mean growth rate is defined as the half of energy conversion rate divided by the wave energy 0.5/. In the Eady waves, the generalized growth rate becomes identical to the conventional one. Sensitivity of growth rate to the UT-LS baroclinicity was studied using an aqua-planet simulation. The UT-LS baroclinicity is enhanced (reduced) in winter (summer) hemisphere, when the solar condition is modified with the SST unchanged. Wave energy and energy conversions integrated over hemispheres are increased (decreased) in the winter (summer) hemisphere from the spring/fall hemisphere. Peak positions of wave energy and its generation rate shift poleward (equatorward) in winter (summer). Generalized growth rate is increased (decreased) in the winter (summer) hemisphere. The UT-LS baroclinicity is considered to enhance growth rates of existing waves and accordingly increases wave energy as well as the low-level baroclinicity does.The growth rate is diagnosed of aqua-planet simulation under equinox/solstice solar conditions with equinox SST. The result suggests that the growth rate may be sensitive to baroclinicity in the upper troposphere as well as that in the

  19. Vertical profiling of SO 2 and SO above Venus' clouds by SPICAV/SOIR solar occultations

    NASA Astrophysics Data System (ADS)

    Belyaev, Denis A.; Montmessin, Franck; Bertaux, Jean-Loup; Mahieux, Arnaud; Fedorova, Anna A.; Korablev, Oleg I.; Marcq, Emmanuel; Yung, Yuk L.; Zhang, Xi

    2012-02-01

    New measurements of sulfur dioxide (SO 2) and monoxide (SO) in the atmosphere of Venus by SPICAV/SOIR instrument onboard Venus Express orbiter provide ample statistics to study the behavior of these gases above Venus' clouds. The instrument (a set of three spectrometers) is capable to sound atmospheric structure above the clouds in several observation modes (nadir, solar and stellar occultations) either in the UV or in the near IR spectral ranges. We present the results from solar occultations in the absorption ranges of SO 2 (190-230 nm, and at 4 μm) and SO (190-230 nm). The dioxide was detected by the SOIR spectrometer at the altitudes of 65-80 km in the IR and by the SPICAV spectrometer at 85-105 km in the UV. The monoxide's absorption was measured only by SPICAV at 85-105 km. We analyzed 39 sessions of solar occultation, where boresights of both spectrometers are oriented identically, to provide complete vertical profiling of SO 2 of the Venus' mesosphere (65-105 km). Here we report the first firm detection and measurements of two SO 2 layers. In the lower layer SO 2 mixing ratio is within 0.02-0.5 ppmv. The upper layer, also conceivable from microwave measurements by Sandor et al. (Sandor, B.J., Todd Clancy, R., Moriarty-Schieven, G., Mills, F.P. [2010]. Icarus 208, 49-60) is characterized by SO 2 increasing with the altitude from 0.05 to 2 ppmv, and the [SO 2]/[SO] ratio varying from 1 to 5. The presence of the high-altitude SO x species could be explained by H 2SO 4 photodissociation under somewhat warmer temperature conditions in Venus mesosphere. At 90-100 km the content of the sulfur dioxide correlates with temperature increasing from 0.1 ppmv at 165-170 K to 0.5-1 ppmv at 190-192 K. It supports the hypothesis of SO 2 production by the evaporation of H 2SO 4 from droplets and its subsequent photolysis at around 100 km.

  20. A Method for Evaluation of Model-Generated Vertical Profiles of Meteorological Variables

    DTIC Science & Technology

    2016-03-01

    profilers and lidar for wind, microwave radiometers for temperature and moisture parameters, and radio acoustic sounding systems (RASSs) for virtual...3 2.1 RAOB Soundings and WRF Output for Profile Generation 3 2.2 Height-Based Profiles 5 2.3 Pressure-Based Profiles 5 3. Comparisons 8 4...values (MD, MAD, SD, and RMSD) for vector wind magnitude and temperature for the user-defined height levels along with the number of samples for each

  1. Aircraft measurements of black carbon vertical profiles show upper tropospheric variability and stability

    NASA Astrophysics Data System (ADS)

    Schwarz, Joshua P.; Weinzierl, Bernadett; Samset, Bjørn H.; Dollner, Maximilian; Heimerl, Katharina; Markovic, Milos Z.; Perring, Anne E.; Ziemba, Luke

    2017-01-01

    We present new data sets of black carbon (BC) aerosol mass mixing ratio (MMR) obtained from aircraft missions over North America, Europe, the Arctic, and the outflow region of Saharan Africa before and after trans-Atlantic transport. The data, collected from 2011 to 2013 with single-particle soot photometers, provide new insight into the variability and distribution of BC over global scales and refine understanding of AeroCom global model ensemble performance. The results indicate extensive global-scale longitudinal mixing of BC above altitude pressures as low as 400 hPa. They also constrain the absolute and temporal variability of upper tropospheric BC MMR and point to opportunities for new tests of global aerosol models in the upper troposphere. A comparison to the AeroCom Phase II results generally reinforces previous estimates of the ensemble performance, except that it also strengthens confidence that the ensemble actually is biased high in the Arctic in all seasons.

  2. Retrieval of Vertical LAI Profiles Over Tropical Rain Forests using Waveform Lidar at La Selva, Costa Rica