Science.gov

Sample records for airborne in-situ observations

  1. Airborne and surface-level in situ observations of wintertime clouds in the Southern Rockies

    NASA Astrophysics Data System (ADS)

    Dorsi, Samuel Winchester

    The phase of cloud water has important impacts on cloud radiative properties, cloud lifetime, and the formation of precipitation. Mixed-phase clouds, or those in which liquid droplets, ice particle and water vapor co-exist, are of particular importance in the Southern Rockies of the United States, where these clouds enhance wintertime mountain precipitation mass and annual water storage in the snowpack. The interaction between multiple water phases within a cloud presents challenges for in situ observation. I describe the existing in situ cloud microphysical instrumentation, and introduce a new instrument for the in situ measurement of total water concentration: the second-generation University of Colorado closed-path tunable-diode laser hygrometer (CLH-2). This compact instrument can be flown within a scientific aircraft under-wing canister and is designed for operation in diverse environmental conditions. During the winter 2010-2011, the CLH-2 was installed on a wind vane at Storm Peak Laboratory (SPL) in the Park Range of Colorado as a part of the Storm Peak Laboratory Cloud Property Validation Experiment (StormVEx) campaign. I apply a new method for determining the bulk mass-dimensional relationship of ice particles from ground-based observations. Despite important difference between airborne and ground-based particle measurements, my parameterization yields particle masses close to those from recent airborne studies that take into account the effect of ice particle shattering on observed number concentrations. Variations in particle density over the course of a storm are suggested by time variations between the observed and parameterized ice water concentrations. Using observations from the Wyoming King Air research aircraft collected during the Colorado Airborne Multi-Phase Cloud Study (CAMPS) in winter 2010-2011, cloud water phase is identified using in situ microphysical measurements. While mixed-phase clouds are identified throughout the study area, the

  2. A comparison of in situ and airborne radar observations of ocean wave directionality

    NASA Technical Reports Server (NTRS)

    Jackson, F. C.; Walton, W. T.; Peng, C. Y.

    1985-01-01

    The directional spectrum of a fully arisen, about 3 m sea as measured by an experimental airborne radar, the NASA K(u)-band radar ocean wave spectrometer (ROWS), is compared to reference pitch-roll buoy data and to the classical SWOP (stereo wave observations project) spectrum for fully developed conditions. The ROWS spectrum, inferred indirectly from backscattered power measurements at 5-km altitude, is shown to be in excellent agreement with the buoy spectrum. Specifically, excellent agreement is found between the two nondirectional height spectra, and mean wave directions and directional spreads as functions of frequency. A comparison of the ROWS and SWOP spectra shows the two spectra to be very similar, in detailed shape as well as in terms of the gross spreading characteristics. Both spectra are seen to exhibit bimodal structures which accord with the Phillips' (1958) resonance mechanism. This observation is thus seen to support Phillips' contention that the SWOP modes were indeed resonance modes, not statistical artifacts.

  3. A case study of observations of volcanic ash from the Eyjafjallajökull eruption: 1. In situ airborne observations

    NASA Astrophysics Data System (ADS)

    Turnbull, Kate; Johnson, Ben; Marenco, Franco; Haywood, Jim; Minikin, Andreas; Weinzierl, Bernadett; Schlager, Hans; Schumann, Ulrich; Leadbetter, Susan; Woolley, Alan

    2012-10-01

    On 17 May 2010, the FAAM BAe-146 aircraft made remote and in situ measurements of the volcanic ash cloud from Eyjafjallajökull over the southern North Sea. The Falcon 20E aircraft operated by Deutsches Zentrum für Luft- und Raumfahrt (DLR) also sampled the ash cloud on the same day. While no "wingtip-to-wingtip" co-ordination was performed, the proximity of the two aircraft allows worthwhile comparisons. Despite the high degree of inhomogeneity (e.g., column ash loadings varied by a factor of three over ˜100 km) the range of ash mass concentrations and the ratios between volcanic ash mass and concentrations of SO2, O3 and CO were consistent between the two aircraft and within expected instrumental uncertainties. The data show strong correlations between ash mass, SO2concentration and aerosol scattering with the FAAM BAe-146 data providing a specific extinction coefficient of 0.6-0.8 m2 g-1. There were significant differences in the observed ash size distribution with FAAM BAe-146 data showing a peak in the mass at ˜3.5μm (volume-equivalent diameter) and DLR data peaking at ˜10μm. Differences could not be accounted for by refractive index and shape assumptions alone. The aircraft in situ and lidar data suggest peak ash concentrations of 500-800 μg m-3with a factor of two uncertainty. Comparing the location of ash observations with the ash dispersion model output highlights differences that demonstrate the difficulties in forecasting such events and the essential nature of validating models using high quality observational data from platforms such as the FAAM BAe-146 and the DLR Falcon.

  4. Investigation of Arctic mixed-phase clouds during VERDI and RACEPAC: Combining airborne remote sensing and in situ observations

    NASA Astrophysics Data System (ADS)

    Ehrlich, André; Wendisch, Manfred

    2015-04-01

    To improve our understanding of Arctic mixed-phase clouds in sea-ice covered areas the airborne research campaign Vertical distribution of ice in Arctic mixed-phase clouds (VERDI, April/May 2012) and the Radiation-Aerosol-Cloud Experiment in the Arctic Circle (RACEPAC, April/May 2014) were initiated by a collaboration of German and French research institutes. The aircraft operated by the Alfred Wegener Institute for Polar and Marine Research, Germany were based in Inuvik, Canada from where the research flights of in total 149 flight hours (62 h during VERDI, 87 h during RACEPAC) were able to cover a wide area above the Canadian Beaufort. The aim of both campaigns was to combine remote sensing and in-situ cloud, aerosol and trace gas measurements to investigate interactions between radiation, cloud and aerosol particles. Remote sensing instrumentation contained a backscatter lidar and spectral solar radiation measurements including a hyperspectral camera. In-situ sampling was highlighted by a suit of comprehensive cloud particle probes, aerosol particle counters and mass spectroscopy as well as trace gas detectors. While during VERDI remote sensing and in-situ measurements were performed by one aircraft (Polar 5) subsequently, for RACEPAC two identical aircraft (Polar 5 & 6, Basler BT-67) were coordinated at different altitudes to horizontally collocate both remote sensing and in-situ measurements. In this way not only the combined analysis of radiative and microphysical processes in the clouds can by studied more reliably, also remote sensing methods can be validated efficiently. Here we will illustrate the scientific strategy of both projects including instrumentation and flight patterns of the research flights. Beside flight missions dedicated to sample low level clouds by remote sensing and in situ probing, flights were also coordinated with satellite overpasses and ground based stations. Exemplary results will be highlighted.

  5. Analysis of field-sampled, in-situ network, and PALS airborne soil moisture observations over SMAPVEX12

    NASA Astrophysics Data System (ADS)

    Adams, J. R.; Berg, A. A.; McNairn, H.; Cosh, M. H.

    2014-12-01

    The Soil Moisture Active Passive Validation Experiment in 2012 (SMAPVEX12) was conducted over an agricultural domain in southern Manitoba, Canada. The purpose of the campaign was to develop ground and airborne datasets for pre-launch validation of SMAP satellite soil moisture retrieval algorithms. Three key soil moisture datasets were collected in support of the campaign objectives: 1) intensive field sampling over (up to) 55 agricultural fields on 17 sampling days; 2) a continuously operated temporary in-situ network (> 30 stations) distributed over the domain; and 3) L-band microwave data from NASA's Passive Active L-band Sensor (PALS) onboard a Twin-Otter aircraft. This presentation addresses whether dense temporary in-situ networks can supplant intensive field-sampling during pre-/post-launch validation campaigns. SMAPVEX12 datasets are examined at the field and aircraft pixel (~800 m) scale, and at the domain scale. Preliminary results demonstrate that, at the field-scale, there is generally limited agreement between a single station and sampled data over its field. Over the duration of the campaign, the majority of temporary soil moisture stations have > 0.04 m3m-3 RMSE with sampled field data, suggesting that a single station has limited representativeness of an agricultural field. Furthermore, the in-situ stations and field-sampled data are compared with PALS generated soil moisture to assess differences in daily RMSE. For wet-periods, both ground datasets provide a comparable RMSE for the PALS estimate. Although for dry-periods, the difference in RMSE between the ground datasets becomes more significant (> 0.04 m3m-3). This is because the field-sampled data exhibit a sharper dry-down than the in-situ station measurements. However, at the domain scale there is strong agreement between the soil moisture datasets. Additional results describe the sources of variability affecting these soil moisture datasets and the statistical number of stations needed to

  6. In situ observations

    NASA Astrophysics Data System (ADS)

    Ehhalt, D. H.

    1980-03-01

    To illustrate capabilities and problems of in situ observations, examples of recent measurements are presented which have a bearing on the chlorofluoromethane-ozone problem. These include: (1) resonance fluorescence for the measurement of Cl and ClO, (2) grab and cryogenic collection of whole air samples for the measurement of CFCl3 and CF2Cl2, (3) impregnated filters for acid chloride, and (4) matrix isolation for HO2 and NO2.

  7. Fault and anthropogenic processes in central California constrained by satellite and airborne InSAR and in-situ observations

    NASA Astrophysics Data System (ADS)

    Liu, Zhen; Lundgren, Paul

    2016-07-01

    , but are subject to severe decorrelation. The L-band ALOS and UAVSAR SAR sensors provide improved coherence compared to the shorter wavelength radar data. Joint analysis of UAVSAR and ALOS interferometry measurements show clear variability in deformation along the fault strike, suggesting variable fault creep and locking at depth and along strike. Modeling selected fault transects reveals a distinct change in surface creep and shallow slip deficit from the central creeping section towards the Parkfield transition. In addition to fault creep, the L-band ALOS, and especially ALOS-2 ScanSAR interferometry, show large-scale ground subsidence in the SJV due to over-exploitation of groundwater. Groundwater related deformation is spatially and temporally variable and is composed of both recoverable elastic and non-recoverable inelastic components. InSAR time series are compared to GPS and well-water hydraulic head in-situ time series to understand water storage processes and mass loading changes. We are currently developing poroelastic finite element method models to assess the influence of anthropogenic processes on surface deformation and fault mechanics. Ongoing work is to better constrain both tectonic and non-tectonic processes and understand their interaction and implication for regional earthquake hazard.

  8. Combined MIPAS (airborne/satellite), CALIPSO and in situ study on large potential NAT particles observed in early Arctic winter stratosphere in December 2011

    NASA Astrophysics Data System (ADS)

    Woiwode, Wolfgang; Höpfner, Michael; Pitts, Michael; Poole, Lamont; Oelhaf, Hermann; Molleker, Sergej; Borrmann, Stephan; Ebersoldt, Andreas; Frey, Wiebke; Gulde, Thomas; Maucher, Guido; Piesch, Christof; Sartorius, Christian; Orphal, Johannes

    2015-04-01

    The understanding of the characteristics of large HNO3-containing particles (potential 'NAT-rocks') involved in vertical redistribution of HNO3 in the polar winter stratosphere is limited due to the difficult accessibility of these particles by observations. While robust polar stratospheric cloud (PSC) classification schemes exist for observations by the space-borne lidar aboard CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) as well as for the passive mid-infrared limb observations by MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), these observations are hardly exploited for the detection of large (diameter >10 μm) NAT particles. This is due to the facts that these particles have low overall number densities, resulting in weak detectable signatures, and that the physical characteristics of these particles (i.e. shape, morphology, HNO3-content and optical characteristics) are uncertain. We investigate collocated and complementary observations of a low-density potential large NAT particle field by the space-borne instruments CALIPSO and MIPAS-ENVISAT as well as the airborne observations by the limb-sounder MIPAS-STR and the in situ particle probe FSSP-100 (Forward Scattering Spectrometer Probe 100) aboard the high-altitude aircraft Geophysica. The observations aboard the Geophysica on 11 December 2011 associated to ESSenCe (ESa Sounder Campaign 2011) provided us the unique opportunity to study in detail the lower boundary region of a PSC where large potential NAT particles (>20 μm in diameter) were detected in situ. We analyse the ambient temperatures and gas-phase composition (HNO3 and H2O), the signatures of the observed particles in the CALIPSO and MIPAS observations, the HNO3-content of these particles suggested by the FSSP-100 and MIPAS-STR observations, and focus on the spectral fingerprint of these particles in the MIPAS-STR observations. While the spectral characterisation of the observed particles is subject

  9. Investigation of Arctic mixed-phase clouds by combining airborne remote sensing and in situ observations during VERDI, RACEPAC and ACLOUD

    NASA Astrophysics Data System (ADS)

    Ehrlich, André; Bierwirth, Eike; Borrmann, Stephan; Crewell, Susanne; Herber, Andreas; Hoor, Peter; Jourdan, Olivier; Krämer, Martina; Lüpkes, Christof; Mertes, Stephan; Neuber, Roland; Petzold, Andreas; Schnaiter, Martin; Schneider, Johannes; Weigel, Ralf; Weinzierl, Bernadett; Wendisch, Manfred

    2016-04-01

    To improve our understanding of Arctic mixed-phase clouds a series of airborne research campaigns has been initiated by a collaboration of German research institutes. Clouds in areas dominated by a close sea-ice cover were observed during the research campaign Vertical distribution of ice in Arctic mixed-phase clouds (VERDI, April/May 2012) and the Radiation-Aerosol-Cloud Experiment in the Arctic Circle (RACEPAC, April/May 2014) which both were based in Inuvik, Canada. The aircraft (Polar 5 & 6, Basler BT-67) operated by the Alfred Wegener Institute for Polar and Marine Research, Germany did cover a wide area above the Canadian Beaufort with in total 149 flight hours (62h during VERDI, 87h during RACEPAC). For May/June 2017 a third campaign ACLOUD (Arctic Clouds - Characterization of Ice, aerosol Particles and Energy fluxes) with base in Svalbard is planned within the Transregional Collaborative Research Centre TR 172 ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3 to investigate Arctic clouds in the transition zone between open ocean and sea ice. The aim of all campaigns is to combine remote sensing and in-situ cloud, aerosol and trace gas measurements to investigate interactions between radiation, cloud and aerosol particles. While during VERDI remote sensing and in-situ measurements were performed by one aircraft subsequently, for RACEPAC and ACLOUD two identical aircraft are coordinated at different altitudes to horizontally collocate both remote sensing and in-situ measurements. The campaign showed that in this way radiative and microphysical processes in the clouds can by studied more reliably and remote sensing methods can be validated efficiently. Here we will illustrate the scientific strategy of the projects including the progress in instrumentation. Differences in the general synoptic and sea ice situation and related changes in cloud properties at the different locations and seasons will be

  10. Decadal changes in ozone and precursor emissions in the Los Angeles California region using in-situ airborne and ground-based field observations, roadside monitoring data, and surface network measurements

    NASA Astrophysics Data System (ADS)

    Pollack, I. B.; Ryerson, T. B.; Trainer, M.; Atlas, E. L.; Blake, D. R.; Flynn, J. H.; Frost, G. J.; Grossberg, N.; Harley, R. A.; Holloway, J. S.; Lefer, B. L.; Lueb, R.; Parrish, D. D.; Peischl, J.

    2011-12-01

    In-situ observations from the Photochemical Assessment Monitoring Stations (PAMS) and the California Air Resources Board (CARB) surface network show decreases in ozone (O3), nitrogen oxide (NOx=NO+NO2), carbon monoxide (CO), and select volatile organic compounds (VOCs) in California's South Coast Air Basin (SoCAB). Decreases in CO, NOx, and VOCs reflect changes, such as improved catalytic converters and reformulated fuels etc., that have been implemented in response to increasingly strict emissions standards placed upon on-road vehicles in the state of California. Here, we compare changes in emissions ratios of NOx and VOCs to CO determined from surface network data collected since 1994 to changes in emissions ratios from biennial roadside studies conducted in west Los Angeles since 1999 and airborne and ground-based measurements from three independent field campaigns conducted in California in 2002, 2008, and 2010. Using the more extensive in-situ surface network data set, we show that decreasing ozone is positively correlated with decreasing abundances of NOx and VOCs and with decreasing VOC/NOx ratio over time. The changes observed from 1994 to present suggest that reductions in both NOx and VOCs and the VOC/NOx ratio over the years have been effective in reducing ozone in the SoCAB.

  11. Microphysical properties of cirrus clouds between 75°N and 25°S derived from extensive airborne in-situ observations

    NASA Astrophysics Data System (ADS)

    Krämer, Martina

    2016-04-01

    Numerous airborne field campaigns were performed in the last decades to record cirrus clouds microphysical properties. Beside the understanding of the processes of cirrus formation and evolution, an additional motivation for those studies is to provide a database to evaluate the representation of cirrus clouds in global climate models. This is of importance for an improved certainty of climate predictions, which are affected by the poor understanding of the microphysical processes of ice clouds (IPCC, 2013). To this end, the observations should ideally cover the complete respective parameter range and not be influenced by instrumental artifacts. However, due to the difficulties in measuring cirrus properties on fast-flying, high-altitude aircraft, some issues with respect to the measurements %evolved have arisen. In particular, concerns about the relative humidity in and around cirrus clouds and the ice crystal number concentrations were under discussion. Too high ice supersaturations as well as ice number concentrations were often reported. These issues have made more challenging the goal of compiling a large database using data from a suite of different instruments that were used on different campaigns. In this study, we have have addressed these challenges and compiled a large data set of cirrus clouds, sampled during eighteen field campaigns between 75°N and 25°S, representing measurements fulfilling the above mentioned requirements. The most recent campaigns were performed in 2014; namely, the ATTREX campaign with the research aircraft Global Hawk and the ML-CIRRUS and ACRIDICON campaigns with HALO. % The observations include ice water content (IWC: 130 hours of observations), ice crystal numbers (N_ice: 83 hours), ice crystal mean mass size (Rice: 83 hours) and relative humidity (RH_ice) in- and outside of cirrus clouds (78 and 140 hours). % We will present the parameters as PDFs versus temperature and derive medians and core ranges (including the most

  12. Using in situ airborne measurements to evaluate three cloud phase products derived from CALIPSO

    NASA Astrophysics Data System (ADS)

    Cesana, G.; Chepfer, H.; Winker, D.; Getzewich, B.; Cai, X.; Jourdan, O.; Mioche, G.; Okamoto, H.; Hagihara, Y.; Noel, V.; Reverdy, M.

    2016-05-01

    We compare the cloud detection and cloud phase determination of three independent climatologies based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) to airborne in situ measurements. Our analysis of the cloud detection shows that the differences between the satellite and in situ measurements mainly arise from three factors. First, averaging CALIPSO Level l data along track before cloud detection increases the estimate of high- and low-level cloud fractions. Second, the vertical averaging of Level 1 data before cloud detection tends to artificially increase the cloud vertical extent. Third, the differences in classification of fully attenuated pixels among the CALIPSO climatologies lead to differences in the low-level Arctic cloud fractions. In another section, we compare the cloudy pixels detected by colocated in situ and satellite observations to study the cloud phase determination. At midlatitudes, retrievals of homogeneous high ice clouds by CALIPSO data sets are very robust (more than 94.6% of agreement with in situ). In the Arctic, where the cloud phase vertical variability is larger within a 480 m pixel, all climatologies show disagreements with the in situ measurements and CALIPSO-General Circulation Models-Oriented Cloud Product (GOCCP) report significant undefined-phase clouds, which likely correspond to mixed-phase clouds. In all CALIPSO products, the phase determination is dominated by the cloud top phase. Finally, we use global statistics to demonstrate that main differences between the CALIPSO cloud phase products stem from the cloud detection (horizontal averaging, fully attenuated pixels) rather than the cloud phase determination procedures.

  13. Utilizing The Synergy of Airborne Backscatter Lidar and In-Situ Measurements for Evaluating CALIPSO

    NASA Astrophysics Data System (ADS)

    Tsekeri, Alexandra; Amiridis, Vassilis; Marenco, Franco; Marinou, Eleni; Rosenberg, Phil; Solomos, Stavros; Trembath, Jamie; Allan, James; Bacak, Asan; Nenes, Athanasios

    2016-06-01

    Airborne campaigns dedicated to satellite validation are crucial for the effective global aerosol monitoring. CALIPSO is currently the only active remote sensing satellite mission, acquiring the vertical profiles of the aerosol backscatter and extinction coefficients. Here we present a method for CALIPSO evaluation from combining lidar and in-situ airborne measurements. The limitations of the method have to do mainly with the in-situ instrumentation capabilities and the hydration modelling. We also discuss the future implementation of our method in the ICE-D campaign (Cape Verde, August 2015).

  14. Detection of airborne Legionella while showering using liquid impingement and fluorescent in situ hybridization (FISH).

    PubMed

    Deloge-Abarkan, Magali; Ha, Thi-Lan; Robine, Enric; Zmirou-Navier, Denis; Mathieu, Laurence

    2007-01-01

    Aerosols of water contaminated with Legionella bacteria constitute the only mode of exposure for humans. However, the prevention strategy against this pathogenic bacteria risk is managed through the survey of water contamination. No relationship linked the Legionella bacteria water concentration and their airborne abundance. Therefore, new approaches in the field of the metrological aspects of Legionella bioaerosols are required. This study was aimed at testing the main principles for bioaerosol collection (solid impaction, liquid impingement and filtration) and the in situ hybridization (FISH) method, both in laboratory and field assays, with the intention of applying such methodologies for airborne Legionella bacteria detection while showering. An aerosolization chamber was developed to generate controlled and reproducible L. pneumophila aerosols. This tool allowed the identification of the liquid impingement method as the most appropriate one for collecting airborne Legionella bacteria. The culturable fraction of airborne L. pneumophila recovered with the liquid impingement principle was 4 and 700 times higher compared to the impaction and filtration techniques, respectively. Moreover, the concentrations of airborne L. pneumophila in the impinger fluid were on average 7.0 x 10(5) FISH-cells m(-3) air with the fluorescent in situ hybridization (FISH) method versus 9.0 x 10(4) CFU m(-3) air with the culture method. These results, recorded under well-controlled conditions, were confirmed during the field experiments performed on aerosols generated by hot water showers in health institutions. This new approach may provide a more accurate characterization of aerobiocontamination by Legionella bacteria.

  15. In situ observations of the atmospheres of terrestrial planetary bodies

    NASA Astrophysics Data System (ADS)

    Harri, Ari-Matti

    2005-11-01

    well as Summary, address the highly successful determination of the Titan atmospheric pressure profile. Publication 8 combines in situ observations and simulations by analyzing Mars Pathfinder measurements with the help of a Martian mesoscale atmospheric model. Finally, in Publication 9 the effect of airborne dust and CO 2 on the radiative transfer in the Martian atmosphere is assessed and a new radiative transfer paramerization scheme for the mesoscale model is introduced.

  16. Integrated Airborne and In-Situ Measurements over Land-Fast Ice near Barrow, AK.

    NASA Astrophysics Data System (ADS)

    Brozena, J. M.; Gardner, J. M.; Liang, R.; Ball, D.; Richter-Menge, J.; Claffey, K. J.; Abelev, A.; Hebert, D. A.; Jones, K.

    2014-12-01

    During March of 2014, the Naval Research Laboratory and the Cold Regions Research and Engineering Laboratory collected an integrated set of airborne and in-situ measurements over two areas of floating, but land-fast ice near the coast of Barrow, AK. The near-shore site was just north of Point Barrow, and the "offshore" site was ~ 20 km east of Point Barrow. The in-situ data provided ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439) and a snow radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The objective of the survey was to aid our understanding of the use of the airborne data to calibrate/validate Cryosat-2 data. Sampling size or "footprint" plays a critical role in the attempt to compare in-situ measurements with airborne (or satellite) measurements. Thus the in-situ data were arranged to minimize aliasing. Ground measurements were collected along transects at both sites consisting of a 2 km long profile of snow depth and ice thickness measurements with periodic boreholes. A 60 m x 400 m swath of snow depth measurements was centered on this profile. Airborne data were collected on five overflights of the two transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The radar measured snow thickness. The freeboard and snow thickness measurements are used to estimate ice thickness via isostasy and density estimates. The central swath of in situ snow depth data allows examination of the effects of cross-track variations considering the relatively large footprint of the snow radar. Assuming a smooth, flat surface the radar range resolution in air is < 4 cm, but the along-track sampling distance is ~ 3 m after unfocussed SAR processing. The width of the footprint varies from ~ 9 m up to about 40 m (beam-limited) for uneven surfaces. However, the radar could not resolve snow thickness

  17. Airborne, In Situ and Laboratory Measurements of the Optical and Photochemical Properties of Surface Marine Waters

    DTIC Science & Technology

    2016-06-07

    Airborne, In Situ And Laboratory Measurements Of The Optical And Photochemical Properties Of Surface Marine Waters Neil V. Blough Department of...matter (CDOM) in marine and estuarine waters , 2) to determine the impact of CDOM on the aquatic light field and remotely-sensed optical signals, 3) to...October 1999 was performed to examine the optical and photochemical properties of waters in the Middle Atlantic Bight and in the Delaware and Chesapeake

  18. Integrated Airborne and In-Situ Measurements Over Land-Fast Ice Near Barrow, AK.

    NASA Astrophysics Data System (ADS)

    Gardner, J. M.; Brozena, J. M.; Richter-Menge, J.; Abelev, A.; Liang, R.; Ball, D.; Claffey, K. J.; Hebert, D. A.; Jones, K.

    2015-12-01

    The Naval Research Laboratory has collected two field seasons of integrated airborne and in-situ measurements over multiple sites of floating, but land-fast ice north of Barrow, AK. During the first season in March of 2014 the Cold Regions Research and Engineering Laboratory led the on-ice group including NRL personnel and Naval Academy midshipmen. The second season (March 2015) included only NRL scientists and midshipmen. The in-situ data provided ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439), a low-frequency SAR (P-band in 2014 and P and L bands in 2015) and a snow/Ku radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The CReSIS radar was updated in 2015 to integrate the snow and Ku radars into a single continuous chirp, thus improving resolution. The objective of the survey was to aid our understanding of the use of the airborne data to calibrate/validate Cryosat-2 data. Sampling size or "footprint" plays a critical role in the attempt to compare in-situ measurements with airborne (or satellite) measurements. Thus the in-situ data were arranged to minimize aliasing. Ground measurements were collected along transects a sites generally consisting of a 2 km long profile of Magnaprobe and EM31 measurements with periodic boreholes. A 60 m x 400 m swath of Magnaprobe measurements was centered on this profile. Airborne data were collected on multiple overflights of the transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The SAR imaged the ice beneath the snow and the snow/Ku radar measured snow thickness. The freeboard measurements and snow thickness are used to estimate ice thickness via isostasy and density estimates. Comparisons and processing methodology will be shown. The results of this ground-truth experiment will inform our analysis of grids of airborne data collected

  19. Airborne Sunphotometer, Airborne in-situ, Space-borne, and Ground-Based Measurements of Troposoheric Aerosol in Ace-2

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Collins, D.; Gasso, S.; Ostrom, E.; Powell, D.; Welton, E.; Durkee, P.; Livingstron, J.; Russell, P.; Flagan, R.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    We report on clear-sky column closure experiments performed in the Canary Islands during the second Aerosol Characterization Experiment (ACE-2) in June/July 1997. We present results obtained by combining airborne sunphotometer and in-situ aerosol measurements taken aboard the Pelican aircraft, space-borne NOAA/AVHRR data and ground-based lidars A wide range of aerosol types was encountered throughout the ACE-2 area, including background Atlantic marine, European pollution-derived, and African mineral dust. During !he two days discussed here, vertical profiles flown in cloud free air masses revealed three distinctly different layers: a marine boundary layer (MBL) with varying pollution levels, an elevated dust layer, and a very clean layer between the MBL and the dust layer. We found that the presence of the elevated dust layer removes the good agreement between satellite and sunphotometer AOD usually found in the absence of the dust layer. Using size-resolved composition information we have computed optical properties of the ambient aerosol from the in-situ measurements and subsequently compared those to the sunphotometer results. In the dust, the agreement in layer aerosol optical depth (380-1060 nm) is 3-8%. In the MBL there is tendency for the in-situ results to be slightly lower than the sunphotometer measurements (10-17% at 525 nm), but these differences are within the combined error bars of the measurements and computations.

  20. In Situ Airborne Measurement of Formaldehyde with a New Laser Induced Fluorescence Instrument

    NASA Astrophysics Data System (ADS)

    Arkinson, H.; Hanisco, T. F.; Cazorla, M.; Fried, A.; Walega, J.

    2012-12-01

    Formaldehyde (HCHO) is a highly reactive and ubiquitous compound in the atmosphere that originates from primary emissions and secondary formation by photochemical oxidation of volatile organic compounds. HCHO is an important precursor to the formation of ozone and an ideal tracer for the transport of boundary layer pollutants to higher altitudes. In situ measurements of HCHO are needed to improve understanding of convective transport mechanisms and the effects of lofted pollutants on ozone production and cloud microphysics in the upper troposphere. The Deep Convective Clouds and Chemistry Project (DC3) field campaign addressed the effects of deep, midlatitude continental convective clouds on the upper troposphere by examining vertical transport of fresh emissions and water aloft and by characterizing subsequent changes in composition and chemistry. Observations targeting convective storms were conducted over Colorado, Alabama, and Texas and Oklahoma. We present measurements of the In Situ Airborne Formaldehyde instrument (ISAF), which uses laser induced fluorescence to achieve the high sensitivity and fast time response required to detect low concentrations in the upper troposphere and capture the fine structure characteristic of convective storm outflow. Preliminary results from DC3 indicate that the ISAF is able to resolve concentrations ranging from under 35 ppt to over 35 ppb, spanning three orders of magnitude, in less than a few minutes. Frequent, abrupt changes in HCHO captured by the ISAF are corroborated by similar patterns observed by simultaneous trace gas and aerosol measurements. Primary HCHO emissions are apparent in cases when the DC-8 flew over combustion sources or biomass burning, and secondary HCHO formation is suggested by observations of enhanced HCHO concurrent with other elevated hydrocarbons. Vertical transport of HCHO is indicated by measurements of over 6 ppb from outflow in the upper troposphere. The DC-8 payload also included the

  1. Estimating Turbulence in Mountainous Regions from Airborne In Situ and Remotely-Sensed Data

    NASA Astrophysics Data System (ADS)

    Strauss, Lukas; Serafin, Stefano; Grubišić, Vanda

    2013-04-01

    Turbulence in atmospheric flow over and around orographic obstacles has been at the focus of numerous studies in the past. Reasons for this range from primary interest in the turbulence-generating processes (gravity-wave breaking, downslope windstorms etc.) to, more recently, issues regarding flight safety. Our work focuses on the observational analysis of turbulence during events of boundary-layer separation and rotor formation. The study is based on observations from two recent field campaigns over the Medicine Bow Mountains in SE Wyoming (NASA06) and the Sierra Nevada in Southern California (T-REX). During these campaigns, the University of Wyoming King Air (UWKA) research aircraft flew straight-and-level legs aligned with the mean wind direction to document the variation of flow and turbulence over the mountain ridges. Aircraft in situ data of wind, pressure and temperature were recorded at a frequency of 25 Hz. The Wyoming Cloud Radar (WCR), carried aboard UWKA, measured Doppler vertical wind velocities at multiple levels at a frequency of 30 Hz. The objective of this work is to quantify turbulence intensity during the observed boundary-layer separation and rotor formation events. To this end, estimates of the variance of vertical wind speed and the eddy-dissipation rate are computed from airborne in situ as well as remotely-sensed data. The comparison of two wave events during the NASA06 campaign reveals similar turbulence intensities with maximum eddy-dissipation rates in the range 0.25-0.30 m2 s-3. The dynamic origin of turbulence, however, appears to be different. For 26 January 2006, results are indicative of a breaking gravity wave aloft leading to wave-induced boundary-layer separation and rotor formation, with maximum turbulence levels located in the rotor interior. In contrast, on 5 February 2006, the lee wave pattern aloft remained laminar while the boundary-layer flow was heavily perturbed. The spatial distribution of turbulence in the flow suggests

  2. Column Closure Studies of Lower Tropospheric Aerosol and Water Vapor During ACE-Asia Using Airborne Sunphotometer, Airborne In-Situ and Ship-Based Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Hegg, A.; Wang, J.; Bates, D.; Redemann, J.; Russells, P. B.; Livingston, J. M.; Jonsson, H. H.; Welton, E. J.; Seinfield, J. H.

    2003-01-01

    We assess the consistency (closure) between solar beam attenuation by aerosols and water vapor measured by airborne sunphotometry and derived from airborne in-situ, and ship-based lidar measurements during the April 2001 Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The airborne data presented here were obtained aboard the Twin Otter aircraft. Comparing aerosol extinction o(550 nm) from four different techniques shows good agreement for the vertical distribution of aerosol layers. However, the level of agreement in absolute magnitude of the derived aerosol extinction varied among the aerosol layers sampled. The sigma(550 nm) computed from airborne in-situ size distribution and composition measurements shows good agreement with airborne sunphotometry in the marine boundary layer but is considerably lower in layers dominated by dust if the particles are assumed to be spherical. The sigma(550 nm) from airborne in-situ scattering and absorption measurements are about approx. 13% lower than those obtained from airborne sunphotometry during 14 vertical profiles. Combining lidar and the airborne sunphotometer measurements reveals the prevalence of dust layers at altitudes up to 10 km with layer aerosol optical depth (from 3.5 to 10 km altitude) of approx. 0.1 to 0.2 (500 nm) and extinction-to-backscatter ratios of 59-71 sr (523 nm). The airborne sunphotometer aboard the Twin Otter reveals a relatively dry atmosphere during ACE- Asia with all water vapor columns less than 1.5 cm and water vapor densities w less than 12 g/cu m. Comparing layer water vapor amounts and w from the airborne sunphotometer to the same quantities measured with aircraft in-situ sensors leads to a high correlation (r(sup 3)=0.96) but the sunphotometer tends to underestimate w by 7%.

  3. Airborne lidar observations in the wintertime Arctic stratosphere - Ozone

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Ismail, S.; Carter, A. F.; Butler, C. F.; Fenn, M. A.; Kooi, S. A.; Tuck, A. F.; Toon, O. B.; Loewenstein, M.; Schoeberl, M. R.

    1990-01-01

    Large-scale distributions of ozone (O3) were measured with an airborne lidar system as part of the 1989 Airborne Arctic Stratospheric Expedition. Measurements of O3 distributions were obtained between January 6 and February 15, 1989, on 15 long-range flights into the polar vortex from the Solar Air Station, Norway. The observed O3 distribution was found to clearly indicate the edge of the polar vortex and to be an effective tracer of dynamical processes in the lower stratosphere. On the last two flights of the expedition, large regions with reduced O3 levels were observed by the lidar inside the polar vortex. Ozone had decreased by as much as 17 percent in the center of these areas, and using the in situ measurements made on the ER-2 aircraft, it was concluded that this decline was due to chemical O3 destruction.

  4. Evaluation of airborne radar-lidar retrieval of ice water content using in-situ probes

    NASA Astrophysics Data System (ADS)

    Khanal, Sujan

    Cloud water content and how that water is distributed across hydrometeors are fundamental cloud microphysical properties that influence cloud dynamical and radiative properties. This study utilizes in-situ and remote sensing data collected by the University of Wyoming King Air research aircraft during the Colorado Airborne Multi-phase Cloud Study, 2010-2011 (CAMPS) field campaign to study the reliability of different cloud water content measuring instruments. It has been shown in several previous studies and again demonstrated here from the CAMPS dataset that Forward Scattering Spectrometer Probe (FSSP) measurements are subject to contamination by shattering artifacts in ice and mixed phase clouds. Contaminated measurements from CAMPS show a significant overestimation of large (D > 28 microm) particles and derived liquid water content (LWC). A new approach is developed to characterize, quantify and correct the shattering contribution in FSSP measurements using ice particle information measured by an OAP cloud probe (2D-C). Comparisons with cloud droplet probe (CDP) measurements show that this new approach adequately corrects for ice shattering effects. This new approach can also be applied to standard FSSP historical datasets. These studies may have erroneous conclusions that can be re-evaluated based on this new correction. University of Colorado closed-path tunable diode laser hygrometer (CLH) total water measurements are used to develop a mass-length relationship for CAMPS dataset to calculate ice water content (IWC) from 2D-C size distribution. Then, these well characterized in-situ instruments are used to evaluate IWC retrievals from combined radar and lidar measurements. Comparison of near flight level remote sensing IWC retrievals with in-situ measurements indicates statistically reasonable agreements (difference in mean values about 33%) providing confidence on the retrieved vertical IWC profile. The collocated airborne radar-lidar measurements combined

  5. Aspects regarding vertical distribution of greenhouse gases resulted from in situ airborne measurements

    NASA Astrophysics Data System (ADS)

    Boscornea, Andreea; Sorin Vajaiac, Nicolae; Ardelean, Magdalena; Benciu, Silviu Stefan

    2016-04-01

    In the last decades the air quality, as well as other components of the environment, has been severely affected by uncontrolled emissions of gases - most known as greenhouse gases (GHG). The main role of GHG is given by the direct influence on the Earth's radiative budget, through Sun light scattering and indirectly by participating in cloud formation. Aldo, many efforts were made for reducing the high levels of these pollutants, e.g., International Panel on Climate Change (IPCC) initiatives, Montreal Protocol, etc., this issue is still open. In this context, this study aims to present several aspects regarding the vertical distribution in the lower atmosphere of some greenhouse gases: water vapours, CO, CO2 and methane. Bucharest and its metropolitan area is one of the most polluted regions of Romania due to high traffic. For assessing the air quality of this area, in situ measurements of water vapours, CO, CO2 and CH4 were performed using a Britten Norman Islander BN2 aircraft equipped with a Picarro gas analyser, model G2401-mc, able to provide precised, continuous and accurate data in real time. This configuration consisting in aircraft and airborne instruments was tested for the first time in Romania. For accomplishing the objectives of the measurement campaign, there were proposed several flight strategies which included vertical and horizontal soundings from 105 m to 3300 m and vice-versa around Clinceni area (20 km West of Bucharest). During 5 days (25.08.2015 - 31.08.2015) were performed 7 flights comprising 10h 18min research flight hours. The measured concentrations of GHS ranged between 0.18 - 2.2 ppm for water vapours with an average maximum value of 1.7 ppm, 0.04 - 0.53 ppm for CO with an average maximum value of 0.21 ppm, 377 - 437.5 ppm for CO2 with an average maximum value of 397 ppm and 1.7 - 6.1 ppm for CH4 with an average maximum value of 2.195 ppm. It was noticed that measured concentrations of GHG are decreasing for high values of sounding

  6. 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

  7. Airborne In Situ and Ground-based Polarimetric Radar Measurements of Tropical Convection in Support of CRYSTAL-FACE

    NASA Technical Reports Server (NTRS)

    Poellot, Michael R.; Kucera, Paul A.

    2004-01-01

    This report describes the work performed by the University of North Dakota (UND) under NASA Grant NAG5-11509, titled Airborne In Situ and Ground-based Polarimetric Radar Measurements of Tropical Convection in Support of CRYSTAL-FACE. This work focused on the collection of data by two key platforms: the UND Citation II research aircraft and the NASA NPOL radar system. The CRYSTAL-FACE (C-F) mission addresses several key issues from the NASA Earth System Enterprise, including the variability of water in the atmosphere, the forcing provided by tropical cirrus and the response of the Earth system to this forcing. In situ measurements and radar observations of tropical convection, cirrus clouds and their environment are core elements of C-F. One of the primary issues that C-F is addressing is the relationship of tropical cirrus anvils to precipitating deep convection. The in situ measurements from C-F are being used to validate remote sensing of Earth-Atmosphere properties, increase our knowledge of upper tropospheric water vapor and its distribution, and increase our knowledge of tropical cirrus cloud morphology and composition. Radar measurements, especially polarimetric diversity observations available fiom the NASA NPOL radar, are providing essential information about the initiation, modulation, and dissipation of convective cores and the generation of associated anvils in tropical convection. Specifically, NPOL radar measurements contain information about convective intensity and its vertical structure for comparison with thermodynamic and kinematic environmental measurements observed from soundings. Because of the polarimetric diversity of MOL, statistics on bulk microphysical properties can be retrieved and compared to the other characteristics of convection and associated cirrus anvils. In summary, the central objectives of this proposal were to deploy the UND Citation research aircraft as an in situ sensing platform for this mission and to provide collaborative

  8. Reconciling In Situ Foliar Nitrogen and Vegetation Structure Measurements with Airborne Imagery Across Ecosystems

    NASA Astrophysics Data System (ADS)

    Flagg, C.

    2015-12-01

    Over the next 30 years the National Ecological Observatory Network (NEON) will monitor environmental and ecological change throughout North America. NEON will provide a suite of standardized data from several ecological topics of interest, including net primary productivity and nutrient cycling, from 60+ sites across 20 eco-climatic domains when fully operational in 2017. The breadth of sampling includes ground-based measurements of foliar nitrogen and vegetation structure, ground-based spectroscopy, airborne LIDAR, and airborne hyperspectral surveys occurring within narrow overlapping time intervals once every five years. While many advancements have been made in linking and scaling in situ data with airborne imagery, establishing these relationships across dozens of highly variable sites poses significant challenges to understanding continental-wide processes. Here we study the relationship between foliar nitrogen content and airborne hyperspectral imagery at different study sites. NEON collected foliar samples from three sites in 2014 as part of a prototype study: Ordway Swisher Biological Station (pine-oak savannah, with active fire management), Jones Ecological Research Center (pine-oak savannah), and San Joaquin Experimental Range (grass-pine oak woodland). Leaf samples and canopy heights of dominant and co-dominant species were collected from trees located within 40 x 40 meter sampling plots within two weeks of aerial LIDAR and hyperspectral surveys. Foliar canopy samples were analyzed for leaf mass per area (LMA), stable isotopes of C and N, C/N content. We also examine agreement and uncertainty between ground based canopy height and airborne LIDAR derived digital surface models (DSM) for each site. Site-scale maps of canopy nitrogen and canopy height will also be presented.

  9. In situ airborne measurements of aerosol optical properties during photochemical pollution events

    NASA Astrophysics Data System (ADS)

    Mallet, M.; van Dingenen, R.; Roger, J. C.; Despiau, S.; Cachier, H.

    2005-02-01

    Dry aerosol optical properties (scattering, absorbing coefficients, and single scattering albedo) were derived from in situ airborne measurements during two photochemical pollution events (25 and 26 June) observed during the Experience sur Site pour Contraindre les Modeles de Pollution atmospherique et de Transport d'Emissions (ESCOMPTE) experiment. Two flights were carried out during daytime (one during the morning and one at noon) over a domain, allowing the investigation of how an air pollution event affects the particle optical properties. Both horizontal distribution and vertical profiles are presented. Results from the horizontal mapping show that plumes of enhanced scattering and absorption are formed in the planetary boundary layer (PBL) during the day in the sea breeze-driven outflow of the coastal urban-industrial area of Marseille-Fos de Berre. The domain-averaged scattering coefficient (at 550 nm) over land σs changes from 35 (28) Mm-1 during land breeze to 63 (43) Mm-1 during sea breeze on 25 June (26 June), with local maxima reaching > 100 Mm-1. The increase in the scattering coefficient is associated with new particle formation, indicative of secondary aerosol formation. Simultaneously, the domain-averaged absorption coefficient increases from 5.6 (3.4) Mm-1 to 9.3 (8.0) Mm-1. The pollution plume leads to strong gradients in the single scattering albedo ωo over the domain studied, with local values as low as 0.73 observed inside the pollution plume. The role of photochemistry and secondary aerosol formation during the 25 June case is shown to increase ωo and to make the aerosol more `reflecting' while the plume moves away from the sources. The lower photochemical activity, observed in the 26 June case, induces a relatively higher contribution of black carbon, making the aerosol more absorbing. Results from vertical profiles at a single near-urban location in the domain indicate that the changes in optical properties happen almost entirely within

  10. Identifying a Sea Breeze Circulation Pattern Over the Los Angeles Basin Using Airborne In Situ Carbon Dioxide Measurements

    NASA Astrophysics Data System (ADS)

    Brannan, A. L.; Schill, S.; Trousdell, J.; Heath, N.; Lefer, B. L.; Yang, M. M.; Bertram, T. H.

    2014-12-01

    The Los Angeles Basin in Southern California is an optimal location for a circulation study, due to its location between the Pacific Ocean to the west and the Santa Monica and San Gabriel mountain ranges to the east, as well as its booming metropolitan population. Sea breeze circulation carries air at low altitudes from coastal to inland regions, where the air rises and expands before returning back towards the coast at higher altitudes. As a result, relatively clean air is expected at low altitudes over coastal regions, but following the path of sea breeze circulation should increase the amount of anthropogenic influence. During the 2014 NASA Student Airborne Research Program, a highly modified DC-8 aircraft completed flights from June 23 to 25 in and around the LA Basin, including missed approaches at four local airports—Los Alamitos and Long Beach (coastal), Ontario and Riverside (inland). Because carbon dioxide (CO2) is chemically inert and well-suited as a conserved atmospheric tracer, the NASA Langley Atmospheric Vertical Observations of CO2 in the Earth's Troposphere (AVOCET) instrument was used to make airborne in situ carbon dioxide measurements. Combining measured wind speed and direction data from the aircraft with CO2 data shows that carbon dioxide can be used to trace the sea breeze circulation pattern of the Los Angeles basin.

  11. Monitoring and Modeling Crop Health and Water Use via in-situ, Airborne and Space-based Platforms

    NASA Astrophysics Data System (ADS)

    McCabe, M. F.

    2014-12-01

    The accurate retrieval of plant water use, health and function together with soil state and condition, represent key objectives in the management and monitoring of large-scale agricultural production. In regions of water shortage or stress, understanding the sustainable use of available water supplies is critical. Unfortunately, this need is all too often limited by a lack of reliable observations. Techniques that balance the demand for reliable ground-based data with the rapid retrieval of spatially distributed crop characteristics represent a needed line of research. Data from in-situ monitoring coupled with advances in satellite retrievals of key land surface variables, provide the information necessary to characterize many crop health and water use features, including evaporation, leaf-chlorophyll and other common vegetation indices. With developments in UAV and quadcopter solutions, the opportunity to bridge the spatio-temporal gap between satellite and ground based sensing now exists, along with the capacity for customized retrievals of crop information. While there remain challenges in the routine application of autonomous airborne systems, the state of current technology and sensor developments provide the capacity to explore the operational potential. While this presentation will focus on the multi-scale estimation of crop-water use and crop-health characteristics from satellite-based sensors, the retrieval of high resolution spatially distributed information from near-surface airborne and ground-based systems will also be examined.

  12. Airborne Sunphotometer Studies of Aerosol Properties and Effects, Including Closure Among Satellite, Suborbital Remote, and In situ Measurements

    NASA Technical Reports Server (NTRS)

    Russlee, Philip B.; Schmid, B.; Redemann, J.; Livingston, J. M.; Bergstrom, R. W.; Ramirez, S. A.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    Airborne sunphotometry has been used to measure aerosols from North America, Europe, and Africa in coordination with satellite and in situ measurements in TARFOX (1996), ACE-2 (1997), PRIDE (2000), and SAFARI 2000. Similar coordinated measurements of Asian aerosols are being conducted this spring in ACE-Asia and are planned for North American aerosols this summer in CLAMS. This paper summarizes the approaches used, key results, and implications for aerosol properties and effects, such as single scattering albedo and regional radiative forcing. The approaches exploit the three-dimensional mobility of airborne sunphotometry to access satellite scenes over diverse surfaces (including open ocean with and without sunglint) and to match exactly the atmospheric layers sampled by airborne in situ measurements and other radiometers. These measurements permit tests of the consistency, or closure, among such diverse measurements as aerosol size-resolved chemical composition; number or mass concentration; light extinction, absorption, and scattering (total, hemispheric back and 180 deg.); and radiative fluxes. In this way the airborne sunphotometer measurements provide a key link between satellite and in situ measurements that helps to understand any discrepancies that are found. These comparisons have led to several characteristic results. Typically these include: (1) Better agreement among different types of remote measurements than between remote and in situ measurements. (2) More extinction derived from transmission measurements than from in situ measurements. (3) Larger aerosol absorption inferred from flux radiometry than from in situ measurements. Aerosol intensive properties derived from these closure studies have been combined with satellite-retrieved fields of optical depth to produce fields of regional radiative forcing. We show results for the North Atlantic derived from AVHRR optical depths and aerosol intensive properties from TARFOX and ACE-2. Companion papers

  13. Airborne Infrared Spectrograph for Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Golub, L.; Cheimets, P.; DeLuca, E. E.; Samra, J.; Judge, P. G.

    2015-12-01

    Direct measurements of the coronal magnetic field have significant potential to enhance our understanding of coronal dynamics, and improve forecasting models. Of particular interest are observations of coronal field lines in the Transition Corona, the transitional region between closed and open flux systems, providing important information on eruptive instabilities and on the origin of the slow solar wind. While current instruments routinely observe the photospheric and chromospheric magnetic fields, the proposed airborne spectrometer will take a step toward the direct observation of coronal fields by measuring plasma emission in the infrared at high spatial and spectral resolution. The targeted lines are five forbidden magnetic dipole transitions between 1.4 and 4 um. The airborne system will consist of a telescope, grating spectrometer and pointing/stabilization system to be flown on the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) during the 21 August 2017 total solar eclipse. We will discuss the scientific objectives of the 2017 flight, describe details of the instrument design, and present the observing program for the eclipse.

  14. Regular, Fast and Accurate Airborne In-Situ Methane Measurements Around the Tropopause

    NASA Astrophysics Data System (ADS)

    Dyroff, Christoph; Rauthe-Schöch, Armin; Schuck, Tanja J.; Zahn, Andreas

    2013-04-01

    We present a laser spectrometer for automated monthly measurements of methane (CH4) mixing ratios aboard the CARIBIC passenger aircraft. The instrument is based on a commercial fast methane analyzer (FMA, Los Gatos Res.), which was modified for fully unattended employment. A laboratory characterization was performed and the results with emphasis on the precision, cross sensitivity to H2O, and accuracy are presented. An in-flight calibration strategy is described, that utilizes CH4 measurements obtained from flask samples taken during the same flights. By statistical comparison of the in-situ measurements with the flask samples we derive a total uncetrainty estimate of ~ 3.85 ppbv (1?) around the tropopause, and ~ 12.4 ppbv (1?) during aircraft ascent and descent. Data from the first two years of airborne operation are presented that span a large part of the northern hemispheric upper troposphere and lowermost stratosphere, with occasional crossings of the tropics on flights to southern Africa. With its high spatial resolution and high accuracy this data set is unprecedented in the highly important atmospheric layer of the tropopause.

  15. Airborne in-situ spectral characterization and concentration estimates of fluorescent organics as a function of depth

    NASA Technical Reports Server (NTRS)

    Tittle, R. A.

    1988-01-01

    The primary purpose of many in-situ airborne light scattering experiments in natural waters is to spectrally characterize the subsurface fluorescent organics and estimate their relative concentrations. This is often done by shining a laser beam into the water and monitoring its subsurface return signal. To do this with the proper interpretation, depth must be taken into account. If one disregards depth dependence when taking such estimates, both their spectral characteristics and their concentrations estimates can be rather ambiguous. A simple airborne lidar configuration is used to detect the subsurface return signal from a particular depth and wavelength. Underwater scatterometer were employed to show that in-situ subsurface organics are very sensitive to depth, but they also require the use of slow moving boats to cover large sample areas. Also, their very entry into the water disturbs the sample it is measuring. The method described is superior and simplest to any employed thus far.

  16. SOFIA'S Challenge: Scheduling Airborne Astronomy Observations

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy

    2005-01-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) is NASA's next generation airborne astronomical observatory, and will commence operations in 2005. The facility consists of a 747-SP modified to accommodate a 2.5 meter telescope. SOFIA is expected to fly an average of 140 science flights per year over its 20 year lifetime. Depending on the nature of the instrument used during flight, 5-15 observations per flight are expected. The SOFIA telescope is mounted aft of the wings on the port side of the aircraft and is articulated through a range of 20deg to 60deg of elevation. The telescope has minimal lateral flexibility; thus, the aircraft must turn constantly to maintain the telescope's focus on an object during observations. A significant problem in future SOFIA operations is that of scheduling flights in support of observations. Investigators are expected to propose small numbers of observations, and many observations must be grouped together to make up single flights. Flight planning for the previous generation airborne observatory, the Kuiper Airborne Observatory (KAO), was done by hand; planners had to choose takeoff time, observations to perform, and decide on setup-actions (called "dead-legs") to position the aircraft prior to observing. This task frequently required between 6-8 hours to plan one flight The scope of the flight planning problem for supporting GI observations with the anticipated flight rate for SOFIA makes the manual approach for flight planning daunting. In response, we have designed an Automated Flight Planner (AFP) that accepts as input a set of requested observations, designated flight days, weather predictions and fuel limitations, and searches automatically for high-quality flight plans that satisfy all relevant aircraft and astronomer specified constraints. The AFP can generate one candidate flight plan in 5-10 minutes, of computation time, a feat beyond the capabilities of human flight planners. The rate at which the AFP can

  17. Fast in situ airborne measurement of ammonia using a mid-infrared off-axis ICOS spectrometer.

    PubMed

    Leen, J Brian; Yu, Xiao-Ying; Gupta, Manish; Baer, Douglas S; Hubbe, John M; Kluzek, Celine D; Tomlinson, Jason M; Hubbell, Mike R

    2013-09-17

    A new ammonia (NH3) analyzer was developed based on off-axis integrated cavity output spectroscopy. Its feasibility was demonstrated by making tropospheric measurements in flights aboard the Department of Energy Gulfstream-1 aircraft. The ammonia analyzer consists of an optical cell, quantum-cascade laser, gas sampling system, control and data acquisition electronics, and analysis software. The NH3 mixing ratio is determined from high-resolution absorption spectra obtained by tuning the laser wavelength over the NH3 fundamental vibration band near 9.67 μm. Excellent linearity is obtained over a wide dynamic range (0-101 ppbv) with a response rate (1/e) of 2 Hz and a precision of ±90 pptv (1σ in 1 s). Two research flights were conducted over the Yakima Valley in Washington State. In the first flight, the ammonia analyzer was used to identify signatures of livestock from local dairy farms with high vertical and spatial resolution under low wind and calm atmospheric conditions. In the second flight, the analyzer captured livestock emission signals under windy conditions. Our results demonstrate that this new ammonia spectrometer is capable of providing fast, precise, and accurate in situ observations of ammonia aboard airborne platforms to advance our understanding of atmospheric compositions and aerosol formation.

  18. Fast In Situ Airborne Measurement of Ammonia Using a Mid-Infrared Off-Axis ICOS Spectrometer

    SciTech Connect

    Leen, J. Brian; Yu, Xiao-Ying; Gupta, Manish; Baer, Douglas S.; Hubbe, John M.; Kluzek, Celine D.; Tomlinson, Jason M.; Hubbell, Mike R.

    2013-08-23

    A new ammonia (NH3) analyzer was developed based on off-axis integrated cavity output spectroscopy. Its feasibility was demonstrated by making tropospheric measurements in flights aboard the Department of Energy Gulfstream-1 aircraft. The ammonia analyzer consists of an optical cell, quantum-cascade laser, gas sampling system, control and data acquisition electronics, and analysis software. The NH3 mixing ratio is determined from high-resolution absorption spectra obtained by tuning the laser wavelength over the NH3 fundamental vibration band near 9.67 μm. Excellent linearity is obtained over a wide dynamic range (0–101 ppbv) with a response rate (1/e) of 2 Hz and a precision of ±90 pptv (1σ in 1 s). Two research flights were conducted over the Yakima Valley in Washington State. In the first flight, the ammonia analyzer was used to identify signatures of livestock from local dairy farms with high vertical and spatial resolution under low wind and calm atmospheric conditions. In the second flight, the analyzer captured livestock emission signals under windy conditions. Finally, our results demonstrate that this new ammonia spectrometer is capable of providing fast, precise, and accurate in situ observations of ammonia aboard airborne platforms to advance our understanding of atmospheric compositions and aerosol formation.

  19. Vertical wind retrieved by airborne lidar and analysis of island induced gravity waves in combination with numerical models and in situ particle measurements

    NASA Astrophysics Data System (ADS)

    Chouza, Fernando; Reitebuch, Oliver; Jähn, Michael; Rahm, Stephan; Weinzierl, Bernadett

    2016-04-01

    This study presents the analysis of island induced gravity waves observed by an airborne Doppler wind lidar (DWL) during SALTRACE. First, the instrumental corrections required for the retrieval of high spatial resolution vertical wind measurements from an airborne DWL are presented and the measurement accuracy estimated by means of two different methods. The estimated systematic error is below -0.05 m s-1 for the selected case of study, while the random error lies between 0.1 and 0.16 m s-1 depending on the estimation method. Then, the presented method is applied to two measurement flights during which the presence of island induced gravity waves was detected. The first case corresponds to a research flight conducted on 17 June 2013 in the Cabo Verde islands region, while the second case corresponds to a measurement flight on 26 June 2013 in the Barbados region. The presence of trapped lee waves predicted by the calculated Scorer parameter profiles was confirmed by the lidar and in situ observations. The DWL measurements are used in combination with in situ wind and particle number density measurements, large-eddy simulations (LES), and wavelet analysis to determine the main characteristics of the observed island induced trapped waves.

  20. In-situ TEM observation on STM tunneling gap

    NASA Astrophysics Data System (ADS)

    Kim, Suhyun; Tanishiro, Yasumasa; Takayanagi, Kunio

    2009-03-01

    Transmission Electron Microscope and Scanning Tunneling Microscope in an ultra high vacuum environment (UHV-TEM-STM) have been combined to simultaneously perform both high resolution TEM and atomically resolved STM experiments. This system was constructed for in-situ investigation of physical property of impurity atoms embedded below semiconductor surface. To image TEM and STM at the same time, crucial requirement is that, the STM image must be acquired under the electron beam irradiation. As a preliminary test, we used HOPG (Highly Oriented Pyrolytic Graphite) sample and tungsten tip as schematically shown in Fig 1(a). Fig 1(b) shows an atomic resolution STM image of HOPG obtained with 300mV sample bias and 3nA tunneling current even in the condition of the electron beam irradiation on the tip. TEM image can be simultaneously acquired by performing In-situ TEM observation on STM tunneling gap formed between the tip and a thin sample. Fig 1(a) Geometry of STM observation on STM tunneling gap Fig 1(b) STM image of HOPG obtained with 300mV sample bias and 3nA tunneling current

  1. Passive remote sensing of large-scale methane emissions from Oil Fields in California's San Joaquin Valley and validation by airborne in-situ measurements - Results from COMEX

    NASA Astrophysics Data System (ADS)

    Gerilowski, Konstantin; Krautwurst, Sven; Thompson, David R.; Thorpe, Andrew K.; Kolyer, Richard W.; Jonsson, Haflidi; Krings, Thomas; Frankenberg, Christian; Horstjann, Markus; Leifer, Ira; Eastwood, Michael; Green, Robert O.; Vigil, Sam; Fladeland, Matthew; Schüttemeyer, Dirk; Burrows, John P.; Bovensmann, Heinrich

    2016-04-01

    The CO2 and MEthane EXperiment (COMEX) was a NASA and ESA funded campaign in support of the HyspIRI and CarbonSat mission definition activities. As a part of this effort, seven flights were performed between June 3 and September 4, 2014 with the Methane Airborne MAPper (MAMAP) remote sensing instrument (operated by the University of Bremen in cooperation with the German Research Centre for Geosciences - GFZ) over the Kern River, Kern Front, and Poso Creek Oil Fields located in California's San Joaquin Valley. MAMAP was installed for the flights aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft, together with: a Picarro fast in-situ greenhouse gas (GHG) analyzer operated by the NASA Ames Research Center, ARC; a 5-hole turbulence probe; and an atmospheric measurement package operated by CIRPAS measuring aerosols, temperature, dew-point, and other atmospheric parameters. Three of the flights were accompanied by the Next Generation Airborne Visual InfraRed Imaging Spectrometer (AVIRIS-NG), operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology, installed aboard a second Twin Otter aircraft. Large-scale, high-concentration CH4 plumes were detected by the MAMAP instrument over the fields and tracked over several kilometers. The spatial distribution of the MAMAP observed plumes was compared to high spatial resolution CH4 anomaly maps derived by AVIRIS-NG imaging spectroscopy data. Remote sensing data collected by MAMAP was used to infer CH4 emission rates and their distributions over the three fields. Aggregated emission estimates for the three fields were compared to aggregated emissions inferred by subsequent airborne in-situ validation measurements collected by the Picarro instrument. Comparison of remote sensing and in-situ flux estimates will be presented, demonstrating the ability of airborne remote sensing data to provide accurate emission estimates for concentrations above the

  2. AVIATR - Aerial Vehicle for In-situ and Airborne Titan Reconnaissance A Titan Airplane Mission Concept

    NASA Technical Reports Server (NTRS)

    Barnes, Jason W.; Lemke, Lawrence; Foch, Rick; McKay, Christopher P.; Beyer, Ross A.; Radebaugh, Jani; Atkinson, David H.; Lorenz, Ralph D.; LeMouelic, Stephane; Rodriguez, Sebastien; Gundlach, Jay; Giannini, Francesco; Bain, Sean; Flasar, F. Michael; Hurford, Terry; Anderson, Carrie M.; Merrison, Jon; Adamkovics, Mate; Kattenhorn, Simon A.; Mitchell, Jonathan; Burr, Devon M.; Colaprete, Anthony; Schaller, Emily; Friedson, A. James; Edgett, Kenneth S.; Coradini, Angioletta; Adriani, Alberto; Sayanagi, Kunio M.; Malaska, Michael J.; Morabito, David; Reh, Kim

    2011-01-01

    We describe a mission concept for a stand-alone Titan airplane mission: Aerial Vehicle for In-situ and Airborne Titan Reconnaissance (AVIATR). With independent delivery and direct-to-Earth communications, AVIATR could contribute to Titan science either alone or as part of a sustained Titan Exploration Program. As a focused mission, AVIATR as we have envisioned it would concentrate on the science that an airplane can do best: exploration of Titan's global diversity. We focus on surface geology/hydrology and lower-atmospheric structure and dynamics. With a carefully chosen set of seven instruments-2 near-IR cameras, 1 near-IR spectrometer, a RADAR altimeter, an atmospheric structure suite, a haze sensor, and a raindrop detector-AVIATR could accomplish a significant subset of the scientific objectives of the aerial element of flagship studies. The AVIATR spacecraft stack is composed of a Space Vehicle (SV) for cruise, an Entry Vehicle (EV) for entry and descent, and the Air Vehicle (AV) to fly in Titan's atmosphere. Using an Earth-Jupiter gravity assist trajectory delivers the spacecraft to Titan in 7.5 years, after which the AVIATR AV would operate for a 1-Earth-year nominal mission. We propose a novel 'gravity battery' climb-then-glide strategy to store energy for optimal use during telecommunications sessions. We would optimize our science by using the flexibility of the airplane platform, generating context data and stereo pairs by flying and banking the AV instead of using gimbaled cameras. AVIATR would climb up to 14 km altitude and descend down to 3.5 km altitude once per Earth day, allowing for repeated atmospheric structure and wind measurements all over the globe. An initial Team-X run at JPL priced the AVIATR mission at FY10 $715M based on the rules stipulated in the recent Discovery announcement of opportunity. Hence we find that a standalone Titan airplane mission can achieve important science building on Cassini's discoveries and can likely do so within

  3. A study to identify and compare airborne systems for in-situ measurements of launch vehicle effluents

    NASA Technical Reports Server (NTRS)

    Thomas, T. J.; Chace, A. S.

    1974-01-01

    An in-situ system for monitoring the concentration of HCl, CO, CO2, and Al2O3 in the cloud of reaction products that form as a result of a launch of solid propellant launch vehicle is studied. A wide array of instrumentation and platforms are reviewed to yield the recommended system. An airborne system suited to monitoring pollution concentrations over urban areas for the purpose of calibrating remote sensors is then selected using a similar methodology to yield the optimal configuration.

  4. Fusing enhanced radar precipitation, in-situ hydrometeorological measurements and airborne LIDAR snowpack estimates in a hyper-resolution hydrologic model to improve seasonal water supply forecasts

    NASA Astrophysics Data System (ADS)

    Gochis, D. J.; Busto, J.; Howard, K.; Mickey, J.; Deems, J. S.; Painter, T. H.; Richardson, M.; Dugger, A. L.; Karsten, L. R.; Tang, L.

    2015-12-01

    Scarcity of spatially- and temporally-continuous observations of precipitation and snowpack conditions in remote mountain watersheds results in fundamental limitations in water supply forecasting. These limitationsin observational capabilities can result in strong biases in total snowmelt-driven runoff amount, the elevational distribution of runoff, river basin tributary contributions to total basin runoff and, equally important for water management, the timing of runoff. The Upper Rio Grande River basin in Colorado and New Mexico is one basin where observational deficiencies are hypothesized to have significant adverse impacts on estimates of snowpack melt-out rates and on water supply forecasts. We present findings from a coordinated observational-modeling study within Upper Rio Grande River basin whose aim was to quanitfy the impact enhanced precipitation, meteorological and snowpack measurements on the simulation and prediction of snowmelt driven streamflow. The Rio Grande SNOwpack and streamFLOW (RIO-SNO-FLOW) Prediction Project conducted enhanced observing activities during the 2014-2015 water year. Measurements from a gap-filling, polarimetric radar (NOXP) and in-situ meteorological and snowpack measurement stations were assimilated into the WRF-Hydro modeling framework to provide continuous analyses of snowpack and streamflow conditions. Airborne lidar estimates of snowpack conditions from the NASA Airborne Snow Observatory during mid-April and mid-May were used as additional independent validations against the various model simulations and forecasts of snowpack conditions during the melt-out season. Uncalibrated WRF-Hydro model performance from simulations and forecasts driven by enhanced observational analyses were compared against results driven by currently operational data inputs. Precipitation estimates from the NOXP research radar validate significantly better against independent in situ observations of precipitation and snow-pack increases

  5. In-situ Observations of Space Debris at ESA

    NASA Astrophysics Data System (ADS)

    Drolshagen, G.

    Information on the small size (millimetre or smaller) space debris and meteoroid population in space can only be obtained by in-situ detectors or the analysis of retrieved hardware. Past, ongoing and planned ESA activities in this field are presented. In 1996 the GORID impact detector was launched into a geostationary orbit on-board the Russian Express-2 telecommunication satellite. This impact ionisation detector had a sensor surface of 0.1 m2. Until July 2002 when the spacecraft was shut down it recorded more than 3000 impacts in the micrometre size range. Inter alia, GORID measured numerous clusters of events, believed to result from debris clouds, and indicated that debris fluxes in GEO are larger than predicted by present models. Another in-situ detector, DEBIE-1, was launched in October 2001 and is operating on-board the small technology satellite PROBA in a low polar orbit. It has two sensors, each of 0.01m2 size, pointing in different directions. A second detector of this type, DEBIE-2 with 3 sensors, is ready for flight on the EuTEF carrier (external payload to ISS). The data from GORID and DEBIE-1 are stored on-line in EDID (European Detector Impact Database). Post-flight impact analyses of retrieved hardware provide detailed information on the encountered meteoroid and debris fluxes over a large range of sizes. ESA initiated several analyses in the past ((EURECA, Hubble Space Telescope (HST) solar arrays). The most recent impact analysis was performed for the HST solar arrays retrieved in March 2002. Measured crater sizes in solar cells ranged from about 1 micron to 7 mm. A total of 175 complete penetrations of the 0.7 mm thick arrays were observed. A chemical analysis of impact residues allowed the distinction between space debris and natural meteoroids. Space debris was found to dominate for sizes smaller than 10 microns and larger than about 1 mm. For intermediate sizes impacts are mainly from meteoroids. Results of the analysis and comparisons with

  6. The Relationship Between Fossil and Dairy Greenhouse Gas Emissions and Complex Urban Land-Use Patterns by In Situ and Remote Sensing Data from Surface Mobile, Airborne, and Satellite Instruments

    NASA Astrophysics Data System (ADS)

    Leifer, I.; Melton, C.; Tratt, D. M.; Kuze, A.; Buckland, K. N.; Butz, A.; Deguchi, A.; Eastwood, M. L.; Fischer, M. L.; Frash, J.; Fladeland, M. M.; Gore, W.; Iraci, L. T.; Johnson, P. D.; Kataoka, F.; Kolyer, R.; Leen, J. B.; Quattrochi, D. A.; Shiomi, K.; Suto, H.; Tanaka, T.; Thompson, D. R.; Yates, E. L.; Van Damme, M.; Yokota, T.

    2015-12-01

    The GOSAT-COMEX-IASI Experiment (Greenhouse gases Observing SATellite-CO2and Methane EXperiment) demonstrated a novel approach to airborne-surface mobile in situ data fusion for interpretation and validation of satellite and airborne remote sensing data of greenhouse gases and direct calculation of flux. Key data were collected for the Chino Dairy in the Los Angeles Basin, California and for the Kern River Oil Fields adjacent to Bakersfield, California. In situ surface and remote sensing greenhouse gas and ammonia observations were compared with IASI and GOSAT retreivals, while hyperspectral imaging data from the AVIRIS, AVIRIS NG, and Mako airborne sensors were analyzed to relate emissions and land use. Figure - platforms participating in the experiment. TANSO-FTS aboard the Ibuki satellite (GOSAT) provided targeted pixels to measure column greenhouse gases. AMOG is the AutoMObile Gas Surveyor which supports a suite of meteorology and in situ trace gas sensors for mobile high speed measurement. AVIRIS, the Airborne Visual InfraRed Imaging Spectrometer aboard the NASA ER-2 airplane collected hyperspectral imaging data at 20 m resolution from 60,000 ft. Mako is a thermal infrared imaging spectrometer that was flown on the Twin Otter International. AJAX is a fighter jet outfitted for science sporting meteorology and greenhouse gas sensors. RAMVan is an upward looking FTIR for measuring column methane and ammonia and other trace gases.

  7. Upper Arctic Ocean velocity structure from in-situ observations

    NASA Astrophysics Data System (ADS)

    Recinos, Beatriz; Rabe, Benjamin; Schauer, Ursula

    2016-04-01

    The gross circulation of the upper and intermediate layers of the Arctic Ocean has been inferred from water mass properties: the mixed layer, containing fresh water from the shelf seas, travels from Siberia towards the Atlantic sector, and the saline and warm layer of Atlantic origin below, follows cyclonic pathways along topographic features. Direct observations of the flow below the sea ice are, however, sparse and difficult to obtain. This research presents the analysis of a unique time series/section of in situ velocity measurements obtained by a drifting ice-tethered platform in the Transpolar Drift near the North Pole. Two instruments were used to obtain in situ measurements of velocity, temperature, salinity and pressure: an Ice-tethered Acoustic Current profiler (ITAC) and an Ice-tethered Profiler (ITP). Both systems were deployed in the Amundsen basin, during the Arctic Ocean expedition ARK XXII/2 of the German Research Vessel Polarstern in September 2007. The systems transmitted profile data from the 14th of September to the 29th of November 2007 and covered a maximum depth range of 23 to 400 m. The results are compared to observations by a shipboard Acoustic Doppler Current Profiler (ADCP) from the 2011 Polarstern expedition ARK-XXVI/3, and wind and ice concentration from satellite reanalysis products. The data set allows an overview of the upper and intermediate circulation along the Lomonosov Ridge. Near-surface velocity and ice drift obtained by the ITAC unit are consistent with the Transpolar Drift Current. Ekman transports calculated from the observed ice drift and assumed ice-ocean drag behaviour suggest that Ekman dynamics influenced velocities at depths greater than the Ekman layer. Direct velocity observations in combination with water mass analyses from the temperature and salinity data, suggest the existence of a current along the Eurasian side of the Lomonosov Ridge within the warm Atlantic layer below the cold halocline. At those depths

  8. In situ observations of medium frequency auroral radio emissions

    NASA Astrophysics Data System (ADS)

    Broughton, M.; Labelle, J. W.; Pfaff, R. F.; Parrot, M.; Yan, X.; Burchill, J. K.

    2013-12-01

    The auroral ionosphere is a region rich with plasma waves that can be studied both in space and on the ground. These waves may mediate energy exchange between particle populations and provide information about the local plasma properties and boundaries. Auroral medium frequency (MF) burst is an impulsive radio emission observed at ground-level from 1.3-4.5 MHz that is associated with local substorm onset. There have been two recent reports of impulsive, broadband, MF waves at high latitudes. Burchill and Pfaff [2005] reported observations from the FAST satellite of impulsive, broadband, MF and low frequency (LF) radio waves. Using data from the DEMETER satellite, Parrot et al. [2009] surveyed MF waves caused by lightning. This study did show a high-latitude population of MF waves. We investigate whether the waves observed by these two satellites are related to auroral MF burst. Using FAST satellite burst mode electric field data from high-latitude (> 60 degrees magnetic), low-altitude (< 1000 km) intervals of moderate to large geomagnetic activity (Kp > 3) from 1996-2002, we have found forty-four examples of impulsive MF waves, all of which are associated with impulsive LF waves. Although MF burst and the waves observed by FAST have similar spectral signatures, they have different magnetic local time dependencies, which suggests that they may be unrelated. A study of MF waves observed at high latitude by DEMETER is ongoing. In situ observations of MF burst could provide crucial information about this heretofore unexplained natural radio emission.

  9. First Results from the COFFEE Instrument: Airborne In-Situ Measurements of Formaldehyde over California

    NASA Astrophysics Data System (ADS)

    Iraci, L. T.; St Clair, J.; Marrero, J. E.; Gore, W.; Swanson, A. K.; Hanisco, T. F.

    2015-12-01

    The Compact Formaldehyde Fluorescence Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of formaldehyde as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. COFFEE, developed at NASA-GSFC, has a sensitivity of 100 pptv (1 sec) and can operate over a wide range of altitudes from the boundary layer to the lower stratosphere. It is mounted in an external wing pod on the Alpha Jet aircraft based at NASA-ARC, which can access altitudes from the surface up to 40,000 ft. We will present results from test flights performed in Fall 2015 over the Central Valley of California. Targets include an oil field, agricultural areas, and highways. Formaldehyde is one of the few urban pollutants that can be measured from space, and we will present plans to compare COFFEE in-situ data with space-based formaldehyde observations such as those from OMI (Aura) and OMPS (SuomiNPP).

  10. In-situ observation of graphene growth on Ni(111)

    NASA Astrophysics Data System (ADS)

    Odahara, Genki; Otani, Shigeki; Oshima, Chuhei; Suzuki, Masahiko; Yasue, Tsuneo; Koshikawa, Takanori

    2011-06-01

    Graphene growth of mono-, bi- and tri-layers on Ni(111) through surface segregation was observed in situ by low energy electron microscopy. The carbon segregation was controlled by adjusting substrate temperature from 1200 K to 1050 K. After the completion of the first layer at 1125 K, the second layer grew at the interface between the first-layer and the substrate at 1050 K. The third layer also started to grow at the same temperature, 1050 K. All the layers exhibited a 1 × 1 atomic structure. The edges of the first-layer islands were straight lines, reflecting the hexagonal atomic structure. On the other hand, the shapes of the second-layer islands were dendritic. The edges of the third-layer islands were again straight lines similar to those of the first-layer islands. The phenomena presumably originate from the changes of interfacial-bond strength of the graphene to Ni substrate depending on the graphene thickness. No nucleation site of graphene layers was directly observed. All the layers expanded out of the field of view and covered the surface. The number of nucleation sites is extremely small on Ni(111) surface. This finding might open the way to grow the high quality, single-domain graphene crystals.

  11. In Situ TEM Observation of Dislocation Evolutionin Polycrystalline UO2

    SciTech Connect

    L. F. HE; 1 M. A. KIRK; Argonne National Laboratory; J. Gan; T. R. ALLEN

    2014-10-01

    In situ transmission electron microscopy observation of polycrystalline UO2 (with average grain size of about 5 lm) irradiated with Kr ions at 600C and 800C was conducted to understand the radiation-induced dislocation evolution under the influence of grain boundaries. The dislocation evolution in the grain interior of polycrystalline UO2 was similar under Kr irradiation at different ion energies and temperatures. As expected, it was characterized by the nucleation and growth of dislocation loops at low irradiation doses, followed by transformation to extended dislocation lines and tangles at high doses. For the first time, a dislocation-denuded zone was observed near a grain boundary in the 1-MeV Kr-irradiated UO2 sample at 800C. The denuded zone in the vicinity of grain boundary was not found when the irradiation temperature was at 600C. The suppression of dislocation loop formation near the boundary is likely due to the enhanced interstitial diffusion toward grain boundary at the high temperature.

  12. In situ observations of diurnal warming at the ocean surface

    NASA Astrophysics Data System (ADS)

    Gentemann, C. L.; Minnett, P. J.

    2007-05-01

    Observations of diurnal temperature variability at the ocean surface have been primarily available only from satellite SST retrievals themselves. Since most satellite observations revisit the same location only infrequently, determining how the ocean surface diurnal heating responds to variability in forcing (mainly insolation and wind speed) has been primarily addressed through theoretical modeling or extrapolation of results from in situ (buoy) observations measured 0.5 m to 1.5 m below the skin layer. Diurnal heating in the skin layer may be quite different than heating at 0.5 m as this layer responds very rapidly to changes in heat and momentum. The Explorer of the Seas, a cruise ship, makes weekly cruises on two alternating tracks through the Caribbean Sea. Measurements from the Marine Atmospheric Emitted Radiance Interferometer (M-AERI) carried on the Explorer of the Seas provide one of the few skin SST data sets, along with ancillary measurements necessary for diurnal investigations. Initial analyses show that the surface signature of diurnal warming in the skin layer is chiefly controlled by the wind speed. The daily peak in diurnal warming is directly related to the minimum wind speed during the day, causing the time of the peak to shift depending on when the minimum winds occur. Fluctuations in wind speed can result in multiple peaks in diurnal heating during a single afternoon. Wind speed is negatively lag-correlated with diurnal warming while insolation is positively lag-correlated. The maximum lag-correlation of wind speed (insolation) with diurnal warming is at a time lag of 30 (50) minutes. Several models of diurnal variability exist. A comparison of several models with each other reveals considerable differences in estimates of diurnal warming. Further validation of the models using M-AERI observed diurnal warming again reveals considerable differences in estimates of warming related to model forcing parameterizations.

  13. Airborne In-Situ Measurements of Formaldehyde over California: First Results from the COFFEE Instrument

    NASA Astrophysics Data System (ADS)

    Marrero, Josette; St. Clair, Jason; Yates, Emma; Swanson, Andrew; Gore, Warren; Iraci, Laura; Hanisco, Thomas

    2016-04-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. We will present results from flights performed over the Central Valley of California, including boundary layer measurements and vertical profiles in the tropospheric column. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. These results will be presented in conjunction with formaldehyde. Targets in the Central Valley consist of an oil field, agricultural areas, and highways, each of which can emit HCHO primarily and generate HCHO through secondary production. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  14. The Saturn Ring Observer: In situ studies of planetary rings

    NASA Astrophysics Data System (ADS)

    Nicholson, P. D.; Tiscareno, M. S.; Spilker, L. J.

    2010-12-01

    As part of the Planetary Science Decadal Survey recently undertaken by the NRC's Space Studies Board for the National Academy of Sciences, studies were commissioned for a number of potential missions to outer planet targets. One of these studies examined the technological feasibility of a mission to carry out in situ studies of Saturn's rings, from a spacecraft placed in a circular orbit above the ring plane: the Saturn Ring Observer. The technical findings and background are discussed in a companion poster by T. R. Spilker et al. Here we outline the science goals of such a mission. Most of the fundamental interactions in planetary rings occur on spatial scales that are unresolved by flyby or orbiter spacecraft. Typical particle sizes in the rings of Saturn are in the 1 cm - 10 m range, and average interparticle spacings are a few meters. Indirect evidence indicates that the vertical thickness of the rings is as little as 5 - 10 m, which implies a velocity dispersion of only a few mm/sec. Theories of ring structure and evolution depend on the unknown characteristics of interparticle collisions and on the size distribution of the ring particles. The SRO could provide direct measurements of both the coefficient of restitution -- by monitoring individual collisions -- and the particles’ velocity dispersion. High-resolution observations of individual ring particles should also permit estimates of their spin states. Numerical simulations of Saturn’s rings incorporating both collisions and self-gravity predict that the ring particles are not uniformly distributed, but are instead clustered into elongated structures referred to as “self-gravity wakes”, which are continually created and destroyed on an orbital timescale. Theory indicates that the average separation between wakes in the A ring is of order 30-100 m. Direct imaging of self-gravity wakes, including their formation and subsequent dissolution, would provide critical validation of these models. Other

  15. An airborne infrared laser spectrometer for in-situ trace gas measurements: application to tropical convection case studies

    NASA Astrophysics Data System (ADS)

    Catoire, V.; Krysztofiak, G.; Robert, C.; Chartier, M.; Jacquet, P.; Guimbaud, C.; Hamer, P. D.; Marécal, V.

    2015-09-01

    A three-channel laser absorption spectrometer called SPIRIT (SPectromètre InfraRouge In situ Toute altitude) has been developed for airborne measurements of trace gases in the troposphere and lower stratosphere. More than three different species can be measured simultaneously with high time resolution (each 1.6 s) using three individual CW-DFB-QCLs (Continuous Wave Distributed FeedBack Quantum Cascade Lasers) coupled to a single Robert multipass optical cell. The lasers are operated in a time-multiplexed mode. Absorption of the mid-infrared radiations occur in the cell (2.8 L with effective path lengths of 134 to 151 m) at reduced pressure, with detection achieved using a HgCdTe detector cooled by Stirling cycle. The performances of the instrument are described, in particular precisions of 1, 1 and 3 %, and volume mixing ratio (vmr) sensitivities of 0.4, 6 and 2.4 ppbv are determined at 1.6 s for CO, CH4 and N2O, respectively (at 1σ confidence level). Estimated accuracies without calibration are about 6 %. Dynamic measuring ranges of about four decades are established. The first deployment of SPIRIT was realized aboard the Falcon-20 research aircraft operated by DLR (Deutsches Zentrum für Luft- und Raumfahrt) within the frame of the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) European project in November-December 2011 over Malaysia. The convective outflows from two large convective systems near Borneo Island (6.0° N-115.5° E and 5.5° N-118.5° E) were sampled above 11 km in altitude on 19 November and 9 December, respectively. Correlated enhancements in CO and CH4 vmr were detected when the aircraft crossed the outflow anvil of both systems. These enhancements were interpreted as the fingerprint of transport from the boundary layer up through the convective system and then horizontal advection in the outflow. Using these observations, the fraction of boundary layer air contained in fresh convective outflow was calculated to range

  16. In situ nonlinear elastic behavior of soil observed by DAET

    SciTech Connect

    Larmat, Carene; Renaud, Guillaume; Rutledge, James T.; Lee, Richard C.; Guyer, Robert A.; Johnson, Paul A.

    2012-07-05

    The key to safe design of critical facilities (strong ground motion in low velocity materials such as soils). Current approaches are predictions from measurements of the elastic non-linear properties of boreholes samples. Need for in-situ, local and complete determination of non-linear properties of soil, rock in response to high-strain motion.

  17. In Situ Observations of Water Vapor and Cirrus IWC in the Pacific TTL During ATTREX

    NASA Astrophysics Data System (ADS)

    Thornberry, T. D.; Rollins, A. W.; Gao, R. S.; Fahey, D. W.; Bui, T. V.; Woods, S.

    2014-12-01

    Despite its very low mixing ratios relative to the troposphere, water vapor in the lower stratosphere (LS) plays a significant role in Earth's radiative balance and climate system and is an important constituent in stratospheric chemistry. The low H2O content of air entering the LS is established to first order by dehydration processes controlled by the cold temperatures of the tropical tropopause layer (TTL). Cirrus clouds occur with high frequency and large spatial extent in the TTL, and those occurring near the thermal tropopause facilitate the final dehydration of stratosphere-bound air parcels. Uncertainties in aspects of the nucleation and growth of cirrus cloud particles and the sparseness of in situ water vapor and cirrus cloud observations with sufficient spatial resolution limit our ability to fully describe the final stages of the dehydration process before air enters the LS in the tropics. The NASA Airborne Tropical Tropopause Experiment (ATTREX) measurement campaign has yielded more than 140 hours of sampling from the Global Hawk UAS in the Pacific TTL during deployments in 2013 and 2014, including more than 30 hours sampling TTL cirrus. The high spatial and temporal resolution in situ measurements of water vapor and cirrus cloud properties made during ATTREX provide an outstanding dataset by which to characterize the Pacific TTL environment and evaluate our current understanding of the dynamical and microphysical processes that result in the dehydration of stratosphere-bound air in this region. Here we present a statistical analysis of the ATTREX water vapor, relative humidity and cirrus cloud crystal number and ice water content (IWC) data in order to investigate cirrus cloud formation and resulting potential for dehydration.

  18. The analysis of in situ and retrieved aerosol properties measured during three airborne field campaigns

    NASA Astrophysics Data System (ADS)

    Corr, Chelsea A.

    Aerosols can directly influence climate, visibility, and photochemistry by scattering and absorbing solar radiation. Aerosol chemical and physical properties determine how efficiently a particle scatters and/or absorbs incoming short-wave solar radiation. Because many types of aerosol can act as nuclei for cloud droplets (CCN) and a smaller population of airborne particles facilitate ice crystal formation (IN), aerosols can also alter cloud-radiation interactions which have subsequent impacts on climate. Thus aerosol properties determine the magnitude and sign of both the direct and indirect impacts of aerosols on radiation-dependent Earth System processes. This dissertation will fill some gaps in our understanding of the role of aerosol properties on aerosol absorption and cloud formation. Specifically, the impact of aerosol oxidation on aerosol spectral (350nm < lambda< 500nm) absorption was examined for two biomass burning plumes intercepted by the NASA DC-S aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission in Spring and Summer 2008. Spectral aerosol single scattering albedo (SSA) retrieved using actinic flux measured aboard the NASA DC-8 was used to calculate the aerosol absorption Angstrom exponents (AAE) for a 6-day-old plume on April 17 th and a 3-hour old plume on June 29th. Higher AAE values for the April 17th plume (6.78+/-0.38) indicate absorption by aerosol was enhanced in the ultraviolet relative to the visible portion of the short-wave spectrum in the older plume compared to the fresher plume (AAE= 3.34 0.11). These differences were largely attributed to the greater oxidation of the organic aerosol in the April 17th plume which can arise either from the aging of primary organic aerosol or the formation of spectrally-absorbing secondary organic aerosol. The validity of the actinic flux retrievals used above were also evaluated in this work by the comparison of SSA retrieved using

  19. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

    SciTech Connect

    Baumgardner, Darrel; Kok, Greg; Avallone, L.; Bansemer, A.; Borrmann, S.; Brown, P.; Bundke, U.; Chuang, P. Y.; Cziczo, D.; Field, P.; Gallagher, M.; Gayet, J. -F.; Korolev, A.; Kraemer, M.; McFarquhar, G.; Mertes, S.; Moehler, O.; Lance, S.; Lawson, P.; Petters, M. D.; Pratt, K.; Roberts, G.; Rogers, D.; Stetzer, O.; Stith, J.; Strapp, W.; Twohy, C.; Wendisch, M.

    2012-02-01

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently under review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.

  20. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

    DOE PAGES

    Baumgardner, Darrel; Kok, Greg; Avallone, L.; ...

    2012-02-01

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently undermore » review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.« less

  1. In situ observation of crystallinity disruption patterns during starch gelatinization.

    PubMed

    Cai, Canhui; Wei, Cunxu

    2013-01-30

    Twelve starches were isolated from the tuberous root of sweet potato, the rhizomes of lotus and yam, the tuber of potato, the corm of water chestnut, and the seeds of pea, bean, barley, wheat, lotus, water caltrop, and ginkgo. Their gelatinization processes were in situ viewed using a polarizing microscope in combination with a hot stage. Four patterns of crystallinity disruption during heating were proposed. The crystallinity disruption initially occurred on the proximal surface of the eccentric hilum, on the distal surface of the eccentric hilum, from the central hilum, or on the surface of the central hilum starch granule. The patterns of initial disruption on the distal surface of the eccentric hilum and on the surface of the central hilum starch were reported for the first time. The heterogeneous distribution of amylose in starch granule might partly explain the different patterns of crystallinity disruption and swelling during gelatinization.

  2. Airborne in situ characterization of dry urban aerosol optical properties around complex topography

    NASA Astrophysics Data System (ADS)

    Targino, Admir Créso; Noone, Kevin J.

    2006-02-01

    In situ data from the 1997 Southern California Ozone Study—NARSTO were used to describe the aerosol optical properties in an urban area whose aerosol distribution is modified as the aerosols are advected over the surrounding topography. The data consist of measurements made with a nephelometer and absorption photometer onboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Pelican aircraft. The cases investigated in this study include vertical profiles flown over coastal sites as well as sites located along some important mountain ranges in southern California. The vertical distribution of the aerosol in the Los Angeles Basin showed a complex configuration, directly related with the local meteorological circulations and the surrounding topography. High spatial and temporal variability in air pollutant concentrations within a relatively small area was found, as indicated by the aerosol scattering and absorption coefficient data. The results suggest that in areas with such complex terrain, a high spatial resolution is required in order to adequately describe the aerosol optical quantities. Principal components analysis (PCA) has been applied to aerosol chemical samples in order to identify the major aerosol types in the Los Angeles Basin. The technique yielded four components that accounted for 78% of the variance in the data set. These were indicative of marine aerosols, urban aerosols, trace elements and secondary aerosol components of traffic emissions and agricultural activities. A Monte Carlo radiation transfer model has been employed to simulate the effects that different aerosol vertical profiles have on the attenuation of solar energy. The cases examined were selected using the results of the PCA and in situ data were used to describe the atmospheric optical properties in the model. These investigations comprise a number of sensitivity tests to evaluate the effects on the results of the location of the aerosol layers as well as

  3. Airborne vacuum ultraviolet resonance fluorescence instrument for in situ measurement of CO

    NASA Astrophysics Data System (ADS)

    Takegawa, N.; Kita, K.; Kondo, Y.; Matsumi, Y.; Parrish, D. D.; Holloway, J. S.; Koike, M.; Miyazaki, Y.; Toriyama, N.; Kawakami, S.; Ogawa, T.

    2001-10-01

    An airborne instrument for fast-response, high-precision measurement of tropospheric carbon monoxide (CO) was developed using a vacuum ultraviolet (VUV) resonance fluorescence technique. The excitation radiation is obtained by a DC discharge CO resonance lamp combined with an optical filter for the CO fourth positive band emission around 150 nm. The optical filter consists of a VUV monochromator and a crystalline quartz window (<147-nm cutoff). The crystalline quartz window ensures a sharp discrimination against wavelengths below 135.7 nm that yield a positive interference from water vapor. Laboratory tests showed that the optical system achieved a precision of 1.1 parts per billion by volume (ppbv) at a CO concentration of 100 ppbv for a 1-s integration period, and the flow system provided a response time (1/e time constant) of ˜2 s. The aircraft measurement campaign Biomass Burning and Lightning Experiment-phase B (BIBLE-B) was conducted between August and September 1999 over the western Pacific and Australia. The flight data obtained during this campaign were used to demonstrate the high precision and fast response of the instrument. An intercomparison of the VUV CO measurement and a gas chromatographic CO measurement was conducted during BIBLE-B. Overall, these two independent measurements showed good agreement, within the experimental uncertainties.

  4. Comparisons of Arctic In-Situ Snow and Ice Data with Airborne Passive Microwave Measurements

    NASA Technical Reports Server (NTRS)

    Markus, T.; Cavalien, D. J.; Gasiewski, A.; Sturm, M.; Klein, M.; Maslanik, J.; Stroeve, J.; Heinrichs, J.; Holmgren, J.; Irisov, V.

    2004-01-01

    As part of the AMSR-E sea ice validation campaign in March 2003, aircraft flights over the Arctic sea ice were coordinated with ground measurements of snow and sea ice properties. The surface-based measurements were in the vicinity of Barrow, AK, and at a Navy ice camp located in the Beaufort Sea. The NASA P-3 aircraft was equipped with the NOAA ETL PSR microwave radiometer that has the same frequencies as the AMSR-E sensor. The goal was to validate the standard AMSR-E products ice temperature and snow depth on sea ice. Ground measurements are the only way to validate these parameters. The higher spatial resolution of the PSR instrument (between 30 and 500 m, depending on altitude) enables a better comparison between ground measurements and microwave data because of the expected smaller spatial variability. Maps of PSR data can then be used for further down-scaling to AMSR-E pixel areas. Initial results show a good qualitative agreement between the in-situ snow depths and the PSR data. Detailed studies are underway and latest results will be presented.

  5. Airborne In-Situ Trace Gas Measurements of Multiple Wildfires in California (2013-2014)

    NASA Astrophysics Data System (ADS)

    Iraci, L. T.; Yates, E. L.; Tanaka, T.; Roby, M.; Gore, W.; Clements, C. B.; Lareau, N.; Ambrosia, V. G.; Quayle, B.; Schroeder, W.

    2014-12-01

    Biomass burning emissions are an important source of a wide range of trace gases and particles that can impact local, regional and global air quality, climate forcing, biogeochemical cycles and human health. In the western US, wildfires dominate over prescribed fires, contributing to atmospheric trace gas budgets and regional and local air pollution. Limited sampling of emissions from wildfires means western US emission estimates rely largely on data from prescribed fires, which may not be a suitable proxy for wildfire emissions. We report here in-situ measurements of carbon dioxide, methane, ozone and water vapor from the plumes of a variety of wildfires sampled in California in the fire seasons of 2013 and 2014. Included in the analysis are the Rim Fire (August - October 2013, near Yosemite National Park), the Morgan Fire (September 2013, near Clayton, CA), and the El Portal Fire (July - August 2014, in Yosemite National Park), among others. When possible, fires were sampled on multiple days. Emission ratios and estimated emission factors will be presented and discussed in the context of fuel composition, plume structure, and fire phase. Correlations of plume chemical composition to MODIS/VIIRS Fire Radiative Power (FRP) and other remote sensing information will be explored. Furthermore, the role of plumes in delivery of enhanced ozone concentrations to downwind municipalities will be discussed.

  6. Airborne observations of vegetation and implications for biogenic emission characterization.

    PubMed

    Hawes, Amy K; Solomon, Susan; Portmann, Robert W; Daniel, John S; Langford, Andrew O; Miller, H LeRoy; Eubank, Charles S; Goldan, Paul; Wiedinmyer, Christine; Atlas, Elliot; Hansel, Armin; Wisthaler, Armin

    2003-12-01

    Measuring hydrocarbons from aircraft represents one way to infer biogenic emissions at the surface. The focus of this paper is to show that complementary remote sensing information can be provided by optical measurements of a vegetation index, which is readily measured with high temporal coverage using reflectance data. We examine the similarities between the vegetation index and in situ measurements of the chemicals isoprene, methacrolein, and alpha-pinene to estimate whether the temporal behavior of the in situ measurements of these chemicals could be better understood by the addition of the vegetation index. Data were compared for flights conducted around Houston in August and September 2000. The three independent sets of chemical measurements examined correspond reasonably well with the vegetation index curves for the majority of flight days. While low values of the vegetation index always correspond to low values of the in situ chemical measurements, high values of the index correspond to both high and low values of the chemical measurements. In this sense it represents an upper limit when compared with in situ data (assuming the calibration constant is adequately chosen). This result suggests that while the vegetation index cannot represent a purely predictive quantity for the in situ measurements, it represents a complementary measurement that can be useful in understanding comparisons of various in situ observations, particularly when these observations occur with relatively low temporal frequency. In situ isoprene measurements and the vegetation index were also compared to an isoprene emission inventory to provide additional insight on broad issues relating to the use of vegetation indices in emission database development.

  7. 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.

  8. Remote sensing of large scale methane emission sources with the Methane Airborne MAPper (MAMAP) instrument over the Kern River and Kern Front Oil fields and validation through airborne in-situ measurements - Initial results from COMEX

    NASA Astrophysics Data System (ADS)

    Gerilowski, K.; Krautwurst, S.; Kolyer, R.; Jonsson, H.; Krings, T.; Horstjann, M.; Leifer, I.; Schuettemeyer, D.; Fladeland, M. M.; Burrows, J. P.; Bovensmann, H.

    2014-12-01

    During three flights performed with the MAMAP (Methane Airborne MAPper) airborne remote sensing instrument in the framework of the CO2 and MEthane Experiment (COMEX) - a NASA and ESA funded campaign in support of HyspIRI and CarbonSat mission definition activities - large scale methane plumes were detected over the Kern River and Kern Front Oil fields in the period between June 3 and 13, 2014. MAMAP was installed for these flights aboard of the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft, together with a Picarro fast in-situ greenhouse gas (GHG) analyzer (operate by the Ames Research Center, ARC), a 5 hole turbulence probe as well as a atmospheric measurement package (operated by CIRPAS), measuring aerosols, temperature, dew-point and other atmospheric parameters. Data collected with the in-situ GHG analyzer will be used for validation of MAMAP remotely sensed data by acquiring vertical cross sections of the discovered plumes at a fixed downwind distance. Precise airborne wind information from the turbulence probe together with ground based wind data from the nearby airport will be used to estimate emission rates from the remote sensed and in-situ measured data. Remote sensed and in-situ data as well as initial flux estimates for the three flights will be presented.

  9. AASE-2 in-situ tracer correlations of methane, nitrous oxide, and ozone as observed aboard the DC-8

    NASA Technical Reports Server (NTRS)

    Collins, J. E., Jr.; Sachse, G. W.; Anderson, B. E.; Weinheimer, A. J.; Walega, J. G.; Ridley, B. A.

    1993-01-01

    We report in situ stratospheric measurements of CH4, N2O, and O3 obtained aboard the NASA DC-8 during the January-March 1992 Airborne Arctic Stratospheric Expedition 2 field campaign. These data demonstrate a strong linear correlation between N2O and CH4 in the lower stratosphere thus indicating that both species are effective tracers of stratospheric air motion. Measurements of both species on constant geometric height surfaces indicate that significant subsidence of the arctic stratospheric air mass occurred at DC-8 altitudes over the course of the AASE-2 expedition. In addition, a widespread reduction in O3 mixing ratios (up to 20%) relative to these conserved tracers was also observed in the lower stratosphere in March as compared to January and February results.

  10. AASE-2 In-Situ Tracer Correlations of Methane Nitrous Oxide and Ozone as Observed Aboard the DC-8

    NASA Technical Reports Server (NTRS)

    Collins, J. E., Jr.; Sachse, G. W.; Anderson, B. E.; Weinheimer, A. J.; Walgea, J. G.; Ridley, B. A.

    1993-01-01

    We report in situ stratospheric measurements of CH4, N2O, and O3 obtained aboard the NASA DC-8 during the January-March 1992 Airborne Arctic Stratospheric Expedition II field campaign. These data demonstrate a strong linear correlation between N2O and CH4 in the lower stratosphere thus indicating that both species are effective tracers of stratospheric air motion. Measurements of both species on constant geometric height surfaces indicate that significant subsidence of the arctic stratospheric air mass occurred at DC-8 altitudes over the course of the AASE-II expedition. In addition, a widespread reduction in O3 mixing ratios (up to 20%) relative to these conserved tracers was also observed in the lower stratosphere in March a compared to January and February results.

  11. SOFIA's Choice: Scheduling Observations for an Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy; Kurklu, Elif; Koga, Dennis (Technical Monitor)

    2002-01-01

    We describe the problem of scheduling observations for an airborne observatory. The problem is more complex than traditional scheduling problems in that it incorporates complex constraints relating the feasibility of an astronomical observation to the position and time of a mobile observatory, as well as traditional temporal constraints and optimization criteria. We describe the problem, its proposed solution and the empirical validation of that solution.

  12. CBSIT 2009: Airborne Validation of Envisat Radar Altimetry and In Situ Ice Camp Measurements Over Arctic Sea Ice

    NASA Technical Reports Server (NTRS)

    Connor, Laurence; Farrell, Sinead; McAdoo, David; Krabill, William; Laxon, Seymour; Richter-Menge, Jacqueline; Markus, Thorsten

    2010-01-01

    with (1) Envisat RA-2 returns retracked optimally for sea ice and (2) in situ measurements of sea ice thickness and snow depth gathered from ice camp surveys. Particular attention is given to lead identification and classification using the continuous photo-imaging system along the Envisat underflight as well as the performance of the snow radar over the ice camp survey lines.

  13. Interpretation of TOMS Observations of Tropical Tropospheric Ozone with a Global Model and In Situ Observations

    NASA Technical Reports Server (NTRS)

    Martin, Randall V.; Jacob, Daniel J.; Logan, Jennifer A.; Bey, Isabelle; Yantosca, Robert M.; Staudt, Amanda C.; Fiore, Arlene M.; Duncan, Bryan N.; Liu, Hongyu; Ginoux, Paul

    2004-01-01

    We interpret the distribution of tropical tropospheric ozone columns (TTOCs) from the Total Ozone Mapping Spectrometer (TOMS) by using a global three-dimensional model of tropospheric chemistry (GEOS-CHEM) and additional information from in situ observations. The GEOS-CHEM TTOCs capture 44% of the variance of monthly mean TOMS TTOCs from the convective cloud differential method (CCD) with no global bias. Major discrepancies are found over northern Africa and south Asia where the TOMS TTOCs do not capture the seasonal enhancements from biomass burning found in the model and in aircraft observations. A characteristic feature of these northern topical enhancements, in contrast to southern tropical enhancements, is that they are driven by the lower troposphere where the sensitivity of TOMS is poor due to Rayleigh scattering. We develop an efficiency correction to the TOMS retrieval algorithm that accounts for the variability of ozone in the lower troposphere. This efficiency correction increases TTOC's over biomass burning regions by 3-5 Dobson units (DU) and decreases them by 2-5 DU over oceanic regions, improving the agreement between CCD TTOCs and in situ observations. Applying the correction to CCD TTOCs reduces by approximately DU the magnitude of the "tropical Atlantic paradox" [Thompson et al, 2000], i.e. the presence of a TTOC enhancement over the southern tropical Atlantic during the northern African biomass burning season in December-February. We reproduce the remainder of the paradox in the model and explain it by the combination of upper tropospheric ozone production from lightning NOx, peristent subsidence over the southern tropical Atlantic as part of the Walker circulation, and cross-equatorial transport of upper tropospheric ozone from northern midlatitudes in the African "westerly duct." These processes in the model can also account for the observed 13-17 DU persistent wave-1 pattern in TTOCs with a maximum above the tropical Atlantic and a minimum

  14. A Rosetta Stone for in situ Observations of Magnetic Reconnection

    NASA Astrophysics Data System (ADS)

    Scudder, J. D.; Daughton, W. S.; Karimabadi, H.; Roytershteyn, V.

    2015-12-01

    Local conditions that constrain the physics of magnetic reconnection in space in 3D will be discussed, including those observable conditions presently used and new ones that enhance experimental closure. Three classes of tests will be discussed: i) proxies for unmeasurable theoretical properties II) observable properties satisfied by all layers that pass mass flux, including those of the reconnection layer, and (iii) observable kinetic tests that are increasingly peculiar to collisionless magnetic reconnection. A Rosetta Stone of state of the art observables will be proposed, including proxies for unmeasurable theoretical local rate of frozen flux violation and measures of the significance of frozen flux encountered. A suite of kinetic observables involving properties peculiar to electrons will also be demonstrated as promising litmus tests for certifying sites of collisionless magnetic reconnection.

  15. Husbandry Trace Gas Emissions from a Dairy Complex By Mobile in Situ and Airborne and Spaceborne Remote Sensing: A Comex Campaign Focus

    NASA Astrophysics Data System (ADS)

    Leifer, I.; Tratt, D. M.; Bovensmann, H.; Buckland, K. N.; Burrows, J. P.; Frash, J.; Gerilowski, K.; Iraci, L. T.; Johnson, P. D.; Kolyer, R.; Krautwurst, S.; Krings, T.; Leen, J. B.; Hu, C.; Melton, C.; Vigil, S. A.; Yates, E. L.; Zhang, M.

    2014-12-01

    Recent field study reviews on the greenhouse gas methane (CH4) found significant underestimation from fossil fuel industry and husbandry. The 2014 COMEX campaign seeks to develop methods to derive CH4 and carbon dioxide (CO2) from remote sensing data by combining hyperspectral imaging (HSI) and non-imaging spectroscopy (NIS) with in situ airborne and surface data. COMEX leverages synergies between high spatial resolution HSI column abundance maps and moderate spectral/spatial resolution NIS. Airborne husbandry data were collected for the Chino dairy complex (East Los Angeles Basin) by NIS-MAMAP, HSI-Mako thermal-infrared (TIR); AVIRIS NG shortwave IR (SWIR), with in situ surface mobile-AMOG Surveyor (AutoMObile greenhouse Gas)-and airborne in situ from a Twin Otter and the AlphaJet. AMOG Surveyor uses in situ Integrated Cavity Off Axis Spectroscopy (OA-ICOS) to measure CH4, CO2, H2O, H2S and NH3 at 5-10 Hz, 2D winds, and thermal anomaly in an adapted commuter car. OA-ICOS provides high precision and accuracy with excellent stability. NH3 and CH4 emissions were correlated at dairy size-scales but not sub-dairy scales in surface and Mako data, showing fine-scale structure and large variations between the numerous dairies in the complex (herd ~200,000-250,000) embedded in an urban setting. Emissions hotspots were consistent between surface and airborne surveys. In June, surface and MAMAP data showed a weak overall plume, while surface and Mako data showed a stronger plume in late (hotter) July. Multiple surface plume transects using NH3 fingerprinting showed East and then NE advection out of the LA Basin consistent with airborne data. Long-term trends were investigated in satellite data. This study shows the value of synergistically combined NH3 and CH4 remote sensing data to the task of CH4 source attribution using airborne and space-based remote sensing (IASI for NH3) and top of atmosphere sensitivity calculations for Sentinel V and Carbon Sat (CH4).

  16. Forecasting ultrafine particle concentrations from satellite and in situ observations

    NASA Astrophysics Data System (ADS)

    Crippa, P.; Castruccio, S.; Pryor, S. C.

    2017-02-01

    Recent innovations in remote sensing technologies and retrievals offer the potential for predicting ultrafine particle (UFP) concentrations from space. However, the use of satellite observations to provide predictions of near-surface UFP concentrations is limited by the high frequency of incomplete predictor values (due to missing observations), the lack of models that account for the temporal dependence of UFP concentrations, and the large uncertainty in satellite retrievals. Herein we present a novel statistical approach designed to address the first two limitations. We estimate UFP concentrations by using lagged estimates of UFP and concurrent satellite-based observations of aerosol optical properties, ultraviolet solar radiation flux, and trace gas concentrations, wherein an expectation maximization algorithm is used to impute missing values in the satellite observations. The resulting model of UFP (derived by using an autoregressive moving average model with exogenous inputs) explains 51 and 28% of the day-to-day variability in concentrations at two sites in eastern North America.

  17. Turbulence in breaking mountain waves and atmospheric rotors estimated from airborne in situ and Doppler radar measurements.

    PubMed

    Strauss, Lukas; Serafin, Stefano; Haimov, Samuel; Grubišić, Vanda

    2015-10-01

    Atmospheric turbulence generated in flow over mountainous terrain is studied using airborne in situ and cloud radar measurements over the Medicine Bow Mountains in southeast Wyoming, USA. During the NASA Orographic Clouds Experiment (NASA06) in 2006, two complex mountain flow cases were documented by the University of Wyoming King Air research aircraft carrying the Wyoming Cloud Radar. The structure of turbulence and its intensity across the mountain range are described using the variance of vertical velocity σw2 and the cube root of the energy dissipation rate ɛ(1/3) (EDR). For a quantitative analysis of turbulence from the cloud radar, the uncertainties in the Doppler wind retrieval have to be taken into account, such as the variance of hydrometeor fall speed and the contamination of vertical Doppler velocity by the horizontal wind. A thorough analysis of the uncertainties shows that 25% accuracy or better can be achieved in regions of moderate to severe turbulence in the lee of the mountains, while only qualitative estimates of turbulence intensity can be obtained outside the most turbulent regions. Two NASA06 events exhibiting large-amplitude mountain waves, mid-tropospheric wave breaking, and rotor circulations are examined. Moderate turbulence is found in a wave-breaking region with σw2 and EDR reaching 4.8 m(2) s(-2) and 0.25 m(2/3) s(-1), respectively. Severe turbulence is measured within the rotor circulations with σw2 and EDR respectively in the ranges of 7.8-16.4 m(2) s(-2) and 0.50-0.77 m(2/3) s(-1). A unique result of this study is the quantitative estimation of the intensity of turbulence and its spatial distribution in the interior of atmospheric rotors, provided by the radar-derived turbulence fields.

  18. Utilization of Airborne and in Situ Data Obtained in SGP99, SMEX02, CLASIC and SMAPVEX08 Field Campaigns for SMAP Soil Moisture Algorithm Development and Validation

    NASA Technical Reports Server (NTRS)

    Colliander, Andreas; Chan, Steven; Yueh, Simon; Cosh, Michael; Bindlish, Rajat; Jackson, Tom; Njoku, Eni

    2010-01-01

    Field experiment data sets that include coincident remote sensing measurements and in situ sampling will be valuable in the development and validation of the soil moisture algorithms of the NASA's future SMAP (Soil Moisture Active and Passive) mission. This paper presents an overview of the field experiment data collected from SGP99, SMEX02, CLASIC and SMAPVEX08 campaigns. Common in these campaigns were observations of the airborne PALS (Passive and Active L- and S-band) instrument, which was developed to acquire radar and radiometer measurements at low frequencies. The combined set of the PALS measurements and ground truth obtained from all these campaigns was under study. The investigation shows that the data set contains a range of soil moisture values collected under a limited number of conditions. The quality of both PALS and ground truth data meets the needs of the SMAP algorithm development and validation. The data set has already made significant impact on the science behind SMAP mission. The areas where complementing of the data would be most beneficial are also discussed.

  19. Airborne aerosol in situ measurements during TCAP: A closure study of total scattering

    SciTech Connect

    Kassianov, Evgueni; Sedlacek, Arthur; Berg, Larry K.; Pekour, Mikhail; Barnard, James; Chand, Duli; Flynn, Connor; Ovchinnikov, Mikhail; Schmid, Beat; Shilling, John; Tomlinson, Jason; Fast, Jerome

    2015-07-31

    We present a framework for calculating the total scattering of both non-absorbing and absorbing aerosol at ambient conditions from aircraft data. Our framework is developed emphasizing the explicit use of chemical composition data for estimating the complex refractive index (RI) of particles, and thus obtaining improved ambient size spectra derived from Optical Particle Counter (OPC) measurements. The feasibility of our framework for improved calculations of total scattering is demonstrated using three types of data collected by the U.S. Department of Energy’s (DOE) aircraft during the Two-Column Aerosol Project (TCAP). Namely, these data types are: (1) size distributions measured by a suite of OPC’s; (2) chemical composition data measured by an Aerosol Mass Spectrometer and a Single Particle Soot Photometer; and (3) the dry total scattering coefficient measured by a integrating nephelometer and scattering enhancement factor measured with a humidification system. We demonstrate that good agreement (~10%) between the observed and calculated scattering can be obtained under ambient conditions (RH < 80%) by applying chemical composition data for the RI-based correction of the OPC-derived size spectra. We also demonstrate that ignoring the RI-based correction or using non-representative RI values can cause a substantial underestimation (~40%) or overestimation (~35%) of the calculated scattering, respectively.

  20. Airborne aerosol in situ measurements during TCAP: A closure study of total scattering

    DOE PAGES

    Kassianov, Evgueni; Sedlacek, Arthur; Berg, Larry K.; ...

    2015-07-31

    We present a framework for calculating the total scattering of both non-absorbing and absorbing aerosol at ambient conditions from aircraft data. Our framework is developed emphasizing the explicit use of chemical composition data for estimating the complex refractive index (RI) of particles, and thus obtaining improved ambient size spectra derived from Optical Particle Counter (OPC) measurements. The feasibility of our framework for improved calculations of total scattering is demonstrated using three types of data collected by the U.S. Department of Energy’s (DOE) aircraft during the Two-Column Aerosol Project (TCAP). Namely, these data types are: (1) size distributions measured by amore » suite of OPC’s; (2) chemical composition data measured by an Aerosol Mass Spectrometer and a Single Particle Soot Photometer; and (3) the dry total scattering coefficient measured by a integrating nephelometer and scattering enhancement factor measured with a humidification system. We demonstrate that good agreement (~10%) between the observed and calculated scattering can be obtained under ambient conditions (RH < 80%) by applying chemical composition data for the RI-based correction of the OPC-derived size spectra. We also demonstrate that ignoring the RI-based correction or using non-representative RI values can cause a substantial underestimation (~40%) or overestimation (~35%) of the calculated scattering, respectively.« less

  1. Airborne Aerosol In situ Measurements during TCAP: A Closure Study of Total Scattering

    SciTech Connect

    Kassianov, Evgueni I.; Berg, Larry K.; Pekour, Mikhail S.; Flynn, Connor J.; Tomlinson, Jason M.; Chand, Duli; Shilling, John E.; Ovchinnikov, Mikhail; Barnard, James C.; Sedlacek, Art; Schmid, Beat

    2015-07-31

    We present here a framework for calculating the total scattering of both non-absorbing and absorbing aerosol at ambient conditions from aircraft data. The synergistically employed aircraft data involve aerosol microphysical, chemical, and optical components and ambient relative humidity measurements. Our framework is developed emphasizing the explicit use of the complementary chemical composition data for estimating the complex refractive index (RI) of particles, and thus obtaining improved ambient size spectra derived from Optical Particle Counter (OPC) measurements. The feasibility of our framework for improved calculations of total aerosol scattering is demonstrated for different ambient conditions with a wide range of relative humidities (from 5 to 80%) using three types of data collected by the U.S. Department of Energy (DOE) G-1 aircraft during the recent Two-Column Aerosol Project (TCAP). Namely, these three types of data employed are: (1) size distributions measured by an Ultra High Sensitivity Aerosol Spectrometer (UHSAS; 0.06-1 µm), a Passive Cavity Aerosol Spectrometer (PCASP; 0.1-3 µm) and a Cloud and Aerosol Spectrometer (CAS; 0.6- >10 µm), (2) chemical composition data measured by an Aerosol Mass Spectrometer (AMS; 0.06-0.6 µm) and a Single Particle Soot Photometer (SP2; 0.06-0.6 µm), and (3) the dry total scattering coefficient measured by a TSI integrating nephelometer at three wavelengths (0.45, 0.55, 0.7 µm) and scattering enhancement factor measured with a humidification system at three RHs (near 45%, 65% and 90%) at a single wavelength (0.525 µm). We demonstrate that good agreement (~10% on average) between the observed and calculated scattering at these three wavelengths can be obtained using the best available chemical composition data for the RI-based correction of the OPC-derived size spectra. We also demonstrate that ignoring the RI-based correction and using non-representative RI values can cause a substantial underestimation (~40

  2. In-Situ Observations in Tropical Cyclones from Ocean Drifters

    NASA Astrophysics Data System (ADS)

    Morzel, J.; Centurioni, L. R.

    2013-05-01

    Ocean Drifters are cost effective, robust and high-quality instruments currently used to observe important variables in the ocean and atmosphere boundary layers during tropical cyclones. They have been configured to measure sea level atmospheric air pressure, wind velocity, solar insolation, sea surface and sub-surface temperature, ocean mixed-layer currents and three-dimensional ocean velocity (typically in depths of 0-150m). Ocean drifters have been successfully deployed in seven hurricanes (Atlantic Ocean) and in four typhoons (Pacific Ocean). Drifters are air-deployed about 18-24 hours ahead of an approaching tropical cyclone from a C-130J aircraft by the 53rd WRS "Hurricane Hunters" at a spacing of 30-50km in a line perpendicular to the expected storm track. On average, the tropical cyclone center has passed within 20km of the nearest drifter, and as close as 3km. Measurements are taken every 15 minutes and are transmitted via Argos or Iridium satellites in real-time and posted to the Global Telecommunication System of the World Weather Watch. The instrument success rate has been 92% in all previous deployments during tropical cyclone conditions from Cat-1 to Cat-5. The high quality of drifter observations has been validated with co-located measurements from dropwindsondes, nearby ocean profiling floats and satellites. Distinct features of the coupled tropical cyclone atmosphere-ocean system observed by the drifters include: the exponential decrease of sea level pressure towards the minimum at the storm center, the radius of maximum winds and their strength, the cold ocean wake on the right hand side of the storm, the inertial currents in the upper ocean, the downward propagation of inertial waves in the ocean, the relatively fast recovery of the sea surface temperature in the cold wake and the longer endurance of the sub-surface wake. In addition, the drifters have detected the response of the atmospheric boundary layer to the ocean's cold wake by measuring

  3. In situ observations of mesoscale undercurrents off eastern Madagascar

    NASA Astrophysics Data System (ADS)

    Ponsoni, Leandro; Aguiar-Gonzalez, Borja; Maas, Leo; van Aken, Hendrik; Nauw, Janine; Ridderinkhof, Herman

    2015-04-01

    The South-West Indian Ocean (SWIO) presents one of the most intriguing western boundary regions of all subtropical gyres. Unlike other gyres, in the SWIO the Madagascar island imposes a physical barrier to the westward flowing South Equatorial Current (SEC), which reaches the Madagascar coast between 17°S and 20°S. At this location, the SEC bifurcates into two branches: the poleward branch feeds into the East Madagascar Current (EMC), which further south will feed the Agulhas Current (AC); on the other hand, the poleward branch feeds into the North Madagascar Current (NMC), which turns around Cape Amber, at the northern tip of Madagascar, and continues westward towards the east coast of Africa. Besides the patterns of the boundary currents described above, undercurrents flowing opposite and beneath the mentioned surface currents are also reported to occur: the equatorward East Madagascar Undercurrent (EMUC) and the poleward North Madagascar Undercurrent (NMUC). This work is based on field studies of both undercurrents. We deployed a cross-slope array of five moorings at 23°S off eastern Madagascar, which was maintained from late 2010 till early 2013 (~2.5 years). A total of 6 Acoustic Doppler Current Profiles and 10 Recording Current Meters were coupled to the moorings. Direct measurements were made from near surface (~50 m) to deep in the water column (~4000 m). The observations reveal a recurring equatorward EMUC with its core hugging the continental slope, at a depth of 1260 m and at an approximate distance of 29 km from the coast. The core velocity has a mean value of 4.1 (±6.3) cm s-1, while maximum speeds reach up to 20 cm -1. The volume transport is estimated to be 1.33 (±1.14) Sv with maxima up to 6 Sv. At the northern tip of Madagascar, off Cape Ambar, we present the first observational evidence of a poleward NMUC. These results are based on a hydrographic cruise (March 2001), where vertical profiles of velocity were sampled across the continental

  4. Snow Cover Changes over Northern Eurasia from in Situ Observations

    NASA Astrophysics Data System (ADS)

    Bulygina, O. N.; Razuvaev, V. N.; Groisman, P. Ya; Korshunova, N. N.

    2012-04-01

    Data. In addition to a standard suite of synoptic snow observations (snow depth, snow type, state of the ground at the meteorological site and its surroundings), we used in our study the national snow survey data set archived at the Russian Institute for Hydrometeorological Information. This dataset has routine snow surveys run throughout the cold season each decade (during the intense snowmelt, each 5 days) at all meteorological stations of the former USSR, thereafter in Russia, since 1966. Prior to 1966 snow surveys are also available but the methodology of observations has substantially changed at that year and our analysis includes data of 958 Russian stations from 1966 to 2011 with a minimal number of missing observations. Surveys run separately along all types of environment typical for the site for 1 to 2 km, describing the current snow cover properties such as snow density, depth, water equivalent, and characteristics of snow and ice crust. Background. During the period of widespread instrumental observations in Northern Eurasia (since 1881), the annual surface air temperature has increased by 1.5°C (in the winter season by 3°C. Close to the north in the Arctic Ocean, the late summer sea ice extent has decreased by 40% providing a near-infinite source of water vapor for the dry Arctic atmosphere in the early cold season months. There is also evidence of more frequent thaw days over northern latitudes of western Eurasia. All these factors affect the state of snow cover. Methods. Regional analysis of snow cover data was carried out using quasi-homogeneous climatic regions. Maps (climatology, trends) are presented mostly for visualization purposes. The area-averaging technique using station values converted to anomalies with respect to a common reference period (in this study, 1966-2011). Anomalies were arithmetically averaged first within 1°N x 2°E grid cells and thereafter by a weighted average value derived over the quasi-homogeneous climatic regions

  5. In-situ Ground-Based and Airborne Formaldehyde Measurements in the Houston Area During TexAQS-II

    NASA Astrophysics Data System (ADS)

    Rappenglueck, B.; Byun, D.; Alvarez, S.; Buhr, M.; Coarfa, V.; Czader, B.; Dasgupta, P.; Estes, M.; Kim, S.; Leuchner, M.; Luke, W.; Shauck, M.; Zanin, G.

    2007-12-01

    Formaldehyde is considered to play a significant role in summertime photochemistry in the Houston area, in particular it is considered an important source for radicals. Secondary formation seems to be the most important fraction of ambient HCHO. Enhanced nighttime values may indicate primary sources. Potential sources may include mobile sources such as traffic exhaust, in particular not well maintained Diesel engines. Other possible sources may include point sources such as coffee roasting and flares from refineries. In this study we focused on the TexAQS-II continuous in-situ formaldehyde data set based on Hantzsch reaction which was obtained in the Ship Channel area (HRM3 and Lynchburg Ferry site) and at the Moody Tower for several weeks. We also include in-situ HCHO measurements obtained with the same technique aboard the Baylor aircraft during TexAQS-II flight missions. Formaldehyde data was compared to several trace gases that are supposed to be coemitted including CO (traffic), ethylene (flares), and SO2 (industry). In order to keep photochemical processes at a minimum special focus was on nighttime data. Case studies will be discussed where meteorological conditions including recirculation and boundary layer developments seem to play a major role in the redistribution of HCHO. Observations will be compared to CMAQ model studies.

  6. The 2011 Draconids: The First European Airborne Meteor Observation Campaign

    NASA Astrophysics Data System (ADS)

    Vaubaillon, Jeremie; Koten, Pavel; Margonis, Anastasios; Toth, Juraj; Rudawska, Regina; Gritsevich, Maria; Zender, Joe; McAuliffe, Jonathan; Pautet, Pierre-Dominique; Jenniskens, Peter; Koschny, Detlef; Colas, Francois; Bouley, Sylvain; Maquet, Lucie; Leroy, Arnaud; Lecacheux, Jean; Borovicka, Jiri; Watanabe, Junichi; Oberst, Jürgen

    2015-02-01

    On 8 October 2011, the Draconid meteor shower (IAU, DRA) was predicted to cause two brief outbursts of meteors, visible from locations in Europe. For the first time, a European airborne meteor observation campaign was organized, supported by ground-based observations. Two aircraft were deployed from Kiruna, Sweden, carrying six scientists, 19 cameras and eight crew members. The flight geometry was chosen such that it was possible to obtain double-station observations of many meteors. The instrument setup on the aircraft as well as on the ground is described in full detail. The main peak from 1900-dust ejecta happened at the predicted time and at the predicted rate. The second peak was observed from the earlier flight and from the ground, and was caused most likely by trails ejected in the nineteenth century. A total of 250 meteors were observed, for which light curve data were derived. The trajectory, velocity, deceleration and orbit of 35 double station meteors were measured. The magnitude distribution index was high, as a result of which there was no excess of meteors near the horizon. The light curve proved to be extremely flat on average, which was unexpected. Observations of spectra allowed us to derive the compositional information of the Draconids meteoroids and showed an early release of sodium, usually interpreted as resulting from fragile meteoroids. Lessons learned from this experience are derived for future airborne meteor shower observation campaigns.

  7. AVIATR—Aerial Vehicle for In-situ and Airborne Titan Reconnaissance. A Titan airplane mission concept

    NASA Astrophysics Data System (ADS)

    Barnes, Jason W.; Lemke, Lawrence; Foch, Rick; McKay, Christopher P.; Beyer, Ross A.; Radebaugh, Jani; Atkinson, David H.; Lorenz, Ralph D.; Le Mouélic, Stéphane; Rodriguez, Sebastien; Gundlach, Jay; Giannini, Francesco; Bain, Sean; Flasar, F. Michael; Hurford, Terry; Anderson, Carrie M.; Merrison, Jon; Ádámkovics, Máté; Kattenhorn, Simon A.; Mitchell, Jonathan; Burr, Devon M.; Colaprete, Anthony; Schaller, Emily; Friedson, A. James; Edgett, Kenneth S.; Coradini, Angioletta; Adriani, Alberto; Sayanagi, Kunio M.; Malaska, Michael J.; Morabito, David; Reh, Kim

    2012-03-01

    We describe a mission concept for a stand-alone Titan airplane mission: Aerial Vehicle for In-situ and Airborne Titan Reconnaissance (AVIATR). With independent delivery and direct-to-Earth communications, AVIATR could contribute to Titan science either alone or as part of a sustained Titan Exploration Program. As a focused mission, AVIATR as we have envisioned it would concentrate on the science that an airplane can do best: exploration of Titan's global diversity. We focus on surface geology/hydrology and lower-atmospheric structure and dynamics. With a carefully chosen set of seven instruments—2 near-IR cameras, 1 near-IR spectrometer, a RADAR altimeter, an atmospheric structure suite, a haze sensor, and a raindrop detector—AVIATR could accomplish a significant subset of the scientific objectives of the aerial element of flagship studies. The AVIATR spacecraft stack is composed of a Space Vehicle (SV) for cruise, an Entry Vehicle (EV) for entry and descent, and the Air Vehicle (AV) to fly in Titan's atmosphere. Using an Earth-Jupiter gravity assist trajectory delivers the spacecraft to Titan in 7.5 years, after which the AVIATR AV would operate for a 1-Earth-year nominal mission. We propose a novel `gravity battery' climb-then-glide strategy to store energy for optimal use during telecommunications sessions. We would optimize our science by using the flexibility of the airplane platform, generating context data and stereo pairs by flying and banking the AV instead of using gimbaled cameras. AVIATR would climb up to 14 km altitude and descend down to 3.5 km altitude once per Earth day, allowing for repeated atmospheric structure and wind measurements all over the globe. An initial Team-X run at JPL priced the AVIATR mission at FY10 715M based on the rules stipulated in the recent Discovery announcement of opportunity. Hence we find that a standalone Titan airplane mission can achieve important science building on Cassini's discoveries and can likely do so

  8. Vertical distribution of trace gas species in the troposphere over the south of West Siberia: comparison of airborne in situ measurements and satellite data

    NASA Astrophysics Data System (ADS)

    Belan, Boris D.; Arshinov, Mikhail Yu.; Belov, Vladimir V.; Gridnev, Yurii V.; Davydov, Denis K.; Machida, Toshinobu; Paris, Jean-Daniel; Nédélec, Philippe; Fofonov, Alexander V.

    2014-05-01

    A comparison of the vertical distributions of O3, CO, CO2 and CH4 derived from the airborne in situ measurements and satellite observations over the southern part of West Siberia is presented. In this study we used data of monthly research flights of 'Optik' TU-134 aircraft laboratory carried out from 2012 to 2013 and data retrieved from measurements of the Infrared Atmospheric Sounding Interferometer (IASI) instrument on-board the MetOp satellite. It was found that differences in ozone mixing ratios between the airborne and satellite data can vary from +3 to +18 ppb at 0.5 km AGL and form -8 to -37 ppb at 7 km AGL, and relative ones ranged from +8 to +30 % and from -12 to -88 %, respectively. Differences in CO concentrations varied from +32 to +103 ppb at 0.5 km height and from -18 to +23 ppb at 3 km. Relative differences were in the range from -4 to +48 % at 0.5 km and from -8 to +20 % at 7 km. The maximal difference in all CH4 profiles reached 150 ppb in the atmospheric boundary layer, and the minimal one was -10 ppb. The average relative difference varied between +2.8 and -0.5 %. The average difference in CO2 concentration lies within ±1.5 ppm, while individual profiles are incommensurable. Maximal and minimal differences during the all flights were observed in the atmospheric boundary layer (+10 and -12 ppm or +2.3 and -3.3%, respectively). In the free troposphere, relative difference decreased down to ±1.0%. This work was funded by Research funds for Global Environmental Monitoring in NIES (Japan), CNRS (France), the French Ministry of Foreign Affairs, CEA (France), Presidium of RAS (Program No. 4), Brunch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5), Interdisciplinary integration projects of Siberian Branch of RAS (No. 35, No. 70, No. 131), Russian Foundation for Basic Research (grants No 14-05-00526, 14-05-00590).

  9. Vertical mass impact and features of Saharan dust intrusions derived from ground-based remote sensing in synergy with airborne in-situ measurements

    NASA Astrophysics Data System (ADS)

    Córdoba-Jabonero, Carmen; Andrey-Andrés, Javier; Gómez, Laura; Adame, José Antonio; Sorribas, Mar; Navarro-Comas, Mónica; Puentedura, Olga; Cuevas, Emilio; Gil-Ojeda, Manuel

    2016-10-01

    A study of the vertical mass impact of Saharan dust intrusions is presented in this work. Simultaneous ground-based remote-sensing and airborne in-situ measurements performed during the AMISOC-TNF campaign over the Tenerife area (Canary Islands) in summertime from 01 July to 11 August 2013 were used for that purpose. A particular dusty (DD) case, associated to a progressively arriving dust intrusion lasting for two days on 31 July (weak incidence) and 01 August (strong incidence), is especially investigated. AERONET AOD and AEx values were ranging, respectively, from 0.2 to 1.4 and 0.35 to 0.05 along these two days. Vertical particle size distributions within fine and coarse modes (0.16-2.8 μm range) were obtained from aircraft aerosol spectrometer measurements. Extinction profiles and Lidar Ratio (LR) values were derived from MPLNET/Micro Pulse Lidar observations. MAXDOAS measurements were also used to retrieve the height-resolved aerosol extinction for evaluation purposes in comparison to Lidar-derived profiles. The synergy between Lidar observations and airborne measurements is established in terms of the Mass Extinction Efficiency (MEE) to calculate the vertical mass concentration of Saharan dust particles. Both the optical and microphysical profilings show dust particles mostly confined in a layer of 4.3 km thickness from 1.7 to 6 km height. LR ranged between 50 and 55 sr, typical values for Saharan dust particles. In addition, this 2-day dust event mostly affected the Free Troposphere (FT), being less intense in the Boundary Layer (BL). In particular, rather high Total Mass Concentrations (TMC) were found on the stronger DD day (01 August 2013): 124, 70 and 21 μg m-3 were estimated, respectively, at FT and BL altitudes and on the near-surface level. This dust impact was enhanced due to the increase of large particles affecting the FT, but also the BL, likely due to their gravitational settling. However, the use of an assumed averaged MEE value can be

  10. Applying Squeaky-Wheel Optimization Schedule Airborne Astronomy Observations

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy; Kuerklue, Elif

    2004-01-01

    We apply the Squeaky Wheel Optimization (SWO) algorithm to the problem of scheduling astronomy observations for the Stratospheric Observatory for Infrared Astronomy, an airborne observatory. The problem contains complex constraints relating the feasibility of an astronomical observation to the position and time at which the observation begins, telescope elevation limits, special use airspace, and available fuel. Solving the problem requires making discrete choices (e.g. selection and sequencing of observations) and continuous ones (e.g. takeoff time and setting up observations by repositioning the aircraft). The problem also includes optimization criteria such as maximizing observing time while simultaneously minimizing total flight time. Previous approaches to the problem fail to scale when accounting for all constraints. We describe how to customize SWO to solve this problem, and show that it finds better flight plans, often with less computation time, than previous approaches.

  11. Constraining climate model simulations of aerosol size distributions over the North Pacific and North America using in-situ airborne measurements

    NASA Astrophysics Data System (ADS)

    McNaughton, Cameron Stuart

    The effect of aerosols on climate is poorly understood compared to green house gases. Aerosols can scatter and/or absorb solar radiation (the "direct effect") and modify cloud properties (the "indirect effect"), affecting Earth's radiation balance and hydrological cycle. Aerosol lifetimes vary from minutes to weeks in the Earth's atmosphere, so they are heterogeneously distributed in both time and space. Over longer time scales, aerosols can influence climate through sulfur (e.g. CLAW Hypothesis) and iron (e.g. Iron Hypothesis) biogeochemical cycling. Determination of natural and anthropogenic aerosol effects on past and future climate can only be achieved using global climate models (GCM's). Satellites allow global measurements of the present-day atmosphere, but require calibration/validation by observations in-situ. Ground- and ship-based observations are confined to the surface boundary layer which can be decoupled from overlying layers and the free troposphere. Here I use in-situ aircraft measurements from five NASA and NSF airborne field campaigns conducted over the North Pacific and North America between 2001 and 2006 to establish a reduced set of airmass types that are stratified vertically, by source region and according to processes governing their characteristics. For each airmass type the aerosol size distribution, mixing state, optical properties and chemical composition are summarized and discussed. In this study I found, (i) parameterizations of background free troposphere aerosol overestimate extinction by ˜50%, minimizing the differences between pre-industrial versus contemporary radiative forcing, (i) meteorological model errors in water vapour mixing ratio can overwhelm the influence of composition-dependent aerosol hygroscopicity on radiating forcing, (iii) aerosol number in convective cloud outflow over North America in summer were reduced by 1/e after ˜2 days with no detectable increase in aerosol mass or decrease in SO2, illustrating the

  12. Airborne passive remote sensing of large-scale methane emissions from oil fields in California's San Joaquin Valley and validation by airborne in-situ measurements - Initial results from COMEX

    NASA Astrophysics Data System (ADS)

    Gerilowski, Konstantin; Krautwurst, Sven; Kolyer, Richard W.; Thompson, David R.; Jonsson, Haflidi; Krings, Thomas; Horstjann, Markus; Leifer, Ira; Eastwood, Michael; Green, Robert O.; Vigil, Sam; Schüttemeyer, Dirk; Fladeland, Matthew; Burrows, John P.; Bovensmann, Heinrich

    2015-04-01

    On several flights performed over the Kern River, Kern Front, and Poso Creek Oil Fields in California between June 3 and September 4, 2014, in the framework of the CO2 and MEthane Experiment (COMEX) - a NASA and ESA funded campaign in support of the HyspIRI and CarbonSat mission definition activities - the Methane Airborne MAPper (MAMAP) remote sensing instrument (operated by the University of Bremen in cooperation with the German Research Centre for Geosciences - GFZ) detected large-scale, high-concentration, methane plumes. MAMAP was installed for the flights aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft, together with a Picarro fast in-situ greenhouse gas (GHG) analyzer (operated by the NASA Ames Research Center, ARC), a 5-hole turbulence probe and an atmospheric measurement package (operated by CIRPAS), measuring aerosols, temperature, dew-point, and other atmospheric parameters. Some of the flights were accompanied by the next generation of the Airborne Visible InfraRed Imaging Spectrometer (AVIRIS-NG), operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology, installed aboard a second Twin Otter aircraft (operated by Twin Otter International). Data collected with the in-situ GHG analyzer were used for validation of the MAMAP and AVIRIS-NG remotely sensed data. The in-situ measurements were acquired in vertical cross sections of the discovered plumes at fixed distances downwind of the sources. Emission rates are estimated from both the remote and in-situ data using wind information from the turbulence probe together with ground-based wind data from the nearby airport. Remote sensing and in-situ data as well as initial flux estimates for selected flights will be presented.

  13. Clear-Sky Closure Studies of Lower Tropospheric Aerosol and Water Vapor During ACE-2 Using Airborne Sunphotometer, Airborne In-Situ, Space-Borne, and Ground-Based Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Livingston, John M.; Russell, Philip B.; Durkee, Philip A.; Jonsson, Haflidi H.; Collins, Donald R.; Flagan, Richard C.; Seinfield, John H.; Gasso, Santiago; Hegg, Dean A.

    2000-01-01

    We report on clear-sky column closure experiments (CLEARCOLUMN) performed in the Canary Islands during the second Aerosol Characterization Experiment (ACE-2) in June/July 1997. We present CLEARCOLUMN results obtained by combining airborne sunphotometer and in-situ (optical particle counter, nephelometer, and absorption photometer) measurements taken aboard the Pelican aircraft, space-borne NOAA/AVHRR data and ground-based lidar and sunphotometer measurements. During both days discussed here, vertical profiles flown in cloud-free air masses revealed 3 distinctly different layers: a marine boundary layer (MBL) with varying pollution levels, an elevated dust layer, and a very clean layer between the MBL and the dust layer. A key result of this study is the achievement of closure between extinction or layer aerosol optical depth (AOD) computed from continuous in-situ aerosol size-distributions and composition and those measured with the airborne sunphotometer. In the dust, the agreement in layer AOD (lambda = 380-1060 nm) is 3-8%. In the MBL there is a tendency for the in-situ results to be slightly lower than the sunphotometer measurements (10-17% at lambda = 525 nm), but these differences are within the combined error bars of the measurements and computations.

  14. The cloud radiation impact from optics simulation and airborne observation

    NASA Astrophysics Data System (ADS)

    Melnikova, Irina; Kuznetsov, Anatoly; Gatebe, Charles

    2017-02-01

    The analytical approach of inverse asymptotic formulas of the radiative transfer theory is used for solving inverse problems of cloud optics. The method has advantages because it does not impose strict constraints, but it is tied to the desired solution. Observations are accomplished in extended stratus cloudiness, above a homogeneous ocean surface. Data from NASA`s Cloud Absorption Radiometer (CAR) during two airborne experiments (SAFARI-2000 and ARCTAS-2008) were analyzed. The analytical method of inverse asymptotic formulas was used to retrieve cloud optical parameters (optical thickness, single scattering albedo and asymmetry parameter of the phase function) and ground albedo in all 8 spectral channels independently. The method is free from a priori restrictions and there is no links to parameters, and it has been applied to data set of different origin and geometry of observations. Results obtained from different airborne, satellite and ground radiative experiments appeared consistence and showed common features of values of cloud parameters and its spectral dependence (Vasiluev, Melnikova, 2004; Gatebe et al., 2014). Optical parameters, retrieved here, are used for calculation of radiative divergence, reflected and transmitted irradiance and heating rates in cloudy atmosphere, that agree with previous observational data.

  15. Under-canopy snow accumulation and ablation measured with airborne scanning LiDAR altimetry and in-situ instrumental measurements, southern Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Kirchner, P. B.; Bales, R. C.; Musselman, K. N.; Molotch, N. P.

    2012-12-01

    We investigated the influence of canopy on snow accumulation and melt in a mountain forest using paired snow on and snow off scanning LiDAR altimetry, synoptic measurement campaigns and in-situ time series data of snow depth, SWE, and radiation collected from the Kaweah River watershed, Sierra Nevada, California. Our analysis of forest cover classified by dominant species and 1 m2 grided mean under canopy snow accumulation calculated from airborne scanning LiDAR, demonstrate distinct relationships between forest class and under-canopy snow depth. The five forest types were selected from carefully prepared 1 m vegetation classifications and named for their dominant tree species, Giant Sequoia, Jeffrey Pine, White Fir, Red Fir, Sierra Lodgepole, Western White Pine, and Foxtail Pine. Sufficient LiDAR returns for calculating mean snow depth per m2 were available for 31 - 44% of the canopy covered area and demonstrate a reduction in snow depth of 12 - 24% from adjacent open areas. The coefficient of variation in snow depth under canopies ranged from 0.2 - 0.42 and generally decreased as elevation increased. Our analysis of snow density snows no statistical significance between snow under canopies and in the open at higher elevations with a weak significance for snow under canopies at lower elevations. Incident radiation measurements made at 15 minute intervals under forest canopies show an input of up to 150 w/m2 of thermal radiation from vegetation to the snow surface on forest plots. Snow accumulated on the mid to high elevation forested slopes of the Sierra Nevada represents the majority of winter snow storage. However snow estimates in forested environments demonstrate a high level of uncertainty due to the limited number of in-situ observations and the inability of most remote sensing platforms to retrieve reflectance under dense vegetation. Snow under forest canopies is strongly mediated by forest cover and decoupled from the processes that dictate accumulation

  16. Arctic polar stratospheric cloud observations by airborne lidar

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Poole, L. R.; Kent, G. S.; Hunt, W. H.; Osborn, M. T.

    1990-01-01

    Lidar observations obtained from January 24 to February 2, 1989, during the Airborne Arctic Stratospheric expedition (AASE) mission further support the existence of two distinct classes (Types 1 and 2) of polar stratospheric clouds (PSCs). Most of the Type 1 PSCs observed were formed by rapid adiabatic cooling and exhibited very low depolarization ratios and low-to-intermediate scattering ratios. Type 2 PSCs were observed in regions of lowest temperature and showed much larger depolarization and scattering ratios, as would be expected from larger ice crystals. PSCs with low scattering ratios but moderate depolarization ratios were observed near the center of the vortex on one flight. These may have been either sparse Type 2 PSCs or Type 1 PSCs formed by less rapid cooling.

  17. Quantifying Spatial and Seasonal Variability in Atmospheric Ammonia with In Situ and Space-Based Observations

    EPA Science Inventory

    Ammonia plays an important role in many biogeochemical processes, yet atmospheric mixing ratios arc not well known. Recently, methods have been developed for retrieving NH3 from space-based observations, but they have not been compared to in situ measurements. We have ...

  18. Interactions between Coronal Mass Ejections Viewed in Coordinated Imaging and In Situ Observations

    NASA Technical Reports Server (NTRS)

    Liu, Ying D.; Luhmann, Janet G.; Moestl, Christian; Martinez-Oliveros, Juan C.; Bale, Stewart D.; Lin, Robert P.; Harrison, Richard A.; Temmer, Manuela; Webb, David F.; Odstrcil, Dusan

    2013-01-01

    The successive coronal mass ejections (CMEs) from 2010 July 30 - August 1 present us the first opportunity to study CME-CME interactions with unprecedented heliospheric imaging and in situ observations from multiple vantage points. We describe two cases of CME interactions: merging of two CMEs launched close in time and overtaking of a preceding CME by a shock wave. The first two CMEs on August 1 interact close to the Sun and form a merged front, which then overtakes the July 30 CME near 1 AU, as revealed by wide-angle imaging observations. Connections between imaging observations and in situ signatures at 1 AU suggest that the merged front is a shock wave, followed by two ejecta observed at Wind which seem to have already merged. In situ measurements show that the CME from July 30 is being overtaken by the shock at 1 AU and is significantly compressed, accelerated and heated. The interaction between the preceding ejecta and shock also results in variations in the shock strength and structure on a global scale, as shown by widely separated in situ measurements from Wind and STEREO B. These results indicate important implications of CME-CME interactions for shock propagation, particle acceleration and space weather forecasting.

  19. In-situ transmission electron microscopy observation of electromigration in Au thin wires.

    PubMed

    Murakami, Yosuke; Arita, Masashi; Hamada, Kouichi; Takahashi, Yasuo

    2012-11-01

    Electromigration of thin Au wire is studied by the use of in-situ transmission electron microscopy (TEM) techniques from the viewpoint of nanogap formation. We use a relatively wide Au wire as a starting material because the position-dependent structure change in the wire provides information of the thermal effect caused by the current flow. In-situ TEM observation, in which current measurements of the Au wire are simultaneously performed, reveals the process of the growth of voids and grains. Finally the formation of a nanogap by electromigration is observed doing with current measurements. All the results observed by in-situ TEM indicate the fact that the thermal effects or temperature increase in the wire region take an important role for the structure change caused by electromigration of Au in the wire. It is suggested that the position of the nanogap can roughly be arranged by setting the wire structure and current direction even though a relatively wide wire was used. The detailed observation by in-situ TEM also suggests that the control of heat generation in the wire makes the nanogap sharp because of the well-controlled recrystallization of Au nanowires.

  20. Monitoring Western Siberian Wetlands from satellite observations and in situ observations

    NASA Astrophysics Data System (ADS)

    Zakharova, E. A.; Kouraev, A. V.; Kolmakova, M. V.; Bazanov, V. A.; Skugarev, A. A.; Berezin, A. E.; Kirpotin, S. N.; Zemtsov, V. A.; Mognard, N. M.

    2009-04-01

    Western Siberia is a large region with mostly flat relief. Most of its territory comprises the watershed of the Ob' river, and much smaller part in the north - watersheds of Nadym, Pur and Taz rivers. Flat relief significantly affects the hydrographical network, creating a multitude of interconnected natural objects - large and small rivers streams, large floodplains, lakes, bogs etc. The region is also abundant with lakes, mainly small ones with surface area less than 1 km2 and depths of 2-5 m. Flooded areas and bogs also act as a buffer zone, providing a dampening "sponge" effect on the water redistribution within the river system. Large area covered by rivers and wetlands results in high rate of evaporation compared to any other large boreal watershed. Contrasting processes are occurring in the Southern and Northern parts of the Western Siberian Plain. In the south, bogs are expanding in the taiga zone and there is progressive swamping which leads to forest death. These bogs act as a carbon sink due to carbon sequestration in their peat layers. Among the bogs of this part of Western Siberia there is the Great Vasiugan Bog - world's largest peatland with a total area of 6.78 million hectares. Bogs of Vasyugan have appeared about 10 000 years ago and since then are constantly growing. 75% of the actual surface of the Great Vasyugan Bog have appeared during the last 500 years. The situation in the northern part (affected by permafrost) is different. The bogs there are reducing their surface and the forest-tundra regions are being subjected to thermokarst activity and colonisation of bogs by trees. Two contrast processes are observed here - a) increase of lake surface due to melting of lakes' coasts, and b) decrease of surface area or disappearance of lakes due to water drain downstream the hydrological network. We combine in situ observations with satellite remote sensing to monitor hydrological regime of the Western Siberian wetlands. Radar altimetry (TOPEX

  1. Airborne observations of far-infrared upwelling radiance in the Arctic

    NASA Astrophysics Data System (ADS)

    Libois, Quentin; Ivanescu, Liviu; Blanchet, Jean-Pierre; Schulz, Hannes; Bozem, Heiko; Leaitch, W. Richard; Burkart, Julia; Abbatt, Jonathan P. D.; Herber, Andreas B.; Aliabadi, Amir A.; Girard, Éric

    2016-12-01

    The first airborne measurements of the Far-InfraRed Radiometer (FIRR) were performed in April 2015 during the panarctic NETCARE campaign. Vertical profiles of spectral upwelling radiance in the range 8-50 µm were measured in clear and cloudy conditions from the surface up to 6 km. The clear sky profiles highlight the strong dependence of radiative fluxes to the temperature inversion typical of the Arctic. Measurements acquired for total column water vapour from 1.5 to 10.5 mm also underline the sensitivity of the far-infrared greenhouse effect to specific humidity. The cloudy cases show that optically thin ice clouds increase the cooling rate of the atmosphere, making them important pieces of the Arctic energy balance. One such cloud exhibited a very complex spatial structure, characterized by large horizontal heterogeneities at the kilometre scale. This emphasizes the difficulty of obtaining representative cloud observations with airborne measurements but also points out how challenging it is to model polar clouds radiative effects. These radiance measurements were successfully compared to simulations, suggesting that state-of-the-art radiative transfer models are suited to study the cold and dry Arctic atmosphere. Although FIRR in situ performances compare well to its laboratory performances, complementary simulations show that upgrading the FIRR radiometric resolution would greatly increase its sensitivity to atmospheric and cloud properties. Improved instrument temperature stability in flight and expected technological progress should help meet this objective. The campaign overall highlights the potential for airborne far-infrared radiometry and constitutes a relevant reference for future similar studies dedicated to the Arctic and for the development of spaceborne instruments.

  2. Airborne In-Situ Measurements of Aerosol and Cloud Microphysical Properties in Mixed-Phase Clouds Under Varying Conditions

    NASA Astrophysics Data System (ADS)

    Comstock, J. M.; Fan, J.; Tomlinson, J. M.; Mei, F.; Hubbe, J. M.; Schmid, B.

    2014-12-01

    Cloud microphysical properties impact the interaction of clouds and radiation in the atmosphere, and can influence atmospheric circulations through changes in cloud phase. Characterizing the conditions that control phase changes and the microphysical properties of mixed-phase clouds is important for improving understanding of physical processes that influence cloud phase. We characterize the aerosol and cloud microphysical properties in relation to the atmospheric dynamic and thermodynamic conditions observed in mixed-phase clouds during several aircraft-based field experiments. The Department of Energy Atmospheric Radiation Measurement program's Gulfstream-1 aircraft was used to sample aerosol and cloud properties in warm and cold clouds during several recent field experiments. We analyze in-situ observations from the CalWater and TCAP field campaigns to examine the variability of cloud properties (phase, hydrometeor size, ice and liquid water content, particle habit) with changes in aerosol, vertical velocity, and temperature. These measurements indicate that in addition to aerosol concentration, vertical velocity strength has important influence on cloud phase in mixed-phase cloud regimes.

  3. Regional Scaling of Airborne Eddy Covariance Flux Observation

    NASA Astrophysics Data System (ADS)

    Sachs, T.; Serafimovich, A.; Metzger, S.; Kohnert, K.; Hartmann, J.

    2014-12-01

    The earth's surface is tightly coupled to the global climate system by the vertical exchange of energy and matter. Thus, to better understand and potentially predict changes to our climate system, it is critical to quantify the surface-atmosphere exchange of heat, water vapor, and greenhouse gases on climate-relevant spatial and temporal scales. Currently, most flux observations consist of ground-based, continuous but local measurements. These provide a good basis for temporal integration, but may not be representative of the larger regional context. This is particularly true for the Arctic, where site selection is additionally bound by logistical constraints, among others. Airborne measurements can overcome this limitation by covering distances of hundreds of kilometers over time periods of a few hours. The Airborne Measurements of Methane Fluxes (AIRMETH) campaigns are designed to quantitatively and spatially explicitly address this issue: The research aircraft POLAR 5 is used to acquire thousands of kilometers of eddy-covariance flux data. During the AIRMETH-2012 and AIRMETH-2013 campaigns we measured the turbulent exchange of energy, methane, and (in 2013) carbon dioxide over the North Slope of Alaska, USA, and the Mackenzie Delta, Canada. Here, we present the potential of environmental response functions (ERFs) for quantitatively linking flux observations to meteorological and biophysical drivers in the flux footprints. We use wavelet transforms of the original high-frequency data to improve spatial discretization of the flux observations. This also enables the quantification of continuous and biophysically relevant land cover properties in the flux footprint of each observation. A machine learning technique is then employed to extract and quantify the functional relationships between flux observations and the meteorological and biophysical drivers. The resulting ERFs are used to extrapolate fluxes over spatio-temporally explicit grids of the study area. The

  4. Analysis of ocean in situ observations and web-based visualization

    NASA Astrophysics Data System (ADS)

    Barth, Alexander; Watelet, Sylvain; Troupin, Charles; Alvera Azcarate, Aida; Santinelli, Giorgio; Hendriksen, Gerrit; Giorgetti, Alessandra; Beckers, Jean-Marie

    2016-04-01

    The sparsity of observations poses a challenge common to various ocean science disciplines. Even for physical parameters where the spatial and temporal coverage is higher, current observational networks undersample a broad spectrum of scales. The situation is generally more severe for chemical and biological parameters because related sensors are less widely deployed. The analysis tool DIVA (Data-Interpolating Variational Analysis) is designed to generate gridded fields from in situ observations. DIVA has been applied to various physical (temperature and salinity), chemical (concentration of nitrate, nitrite and phosphate) and biological parameters (abundance of a species) in the context of different European projects (SeaDataNet, EMODnet Chemistry and EMODnet Biology). We show the technologies used to visualize the gridded fields based on the Web Map Services standard. Visualization of analyses from in situ observations provides a unique set of challenges since the accuracy of the analysed field is not spatially uniform as it strongly depends on the observations location. In addition, an adequate handling of depth and time dimensions is essential. Beside visualizing the gridded fields, access is also given to the underlying observations. It is thus also possible to view more detailed information about the variability of the observations. The in situ observation visualization service allows one to display vertical profiles and time series and it is built upon OGC standards (the Web Feature Service and Web Processing Services) and following recommendation from the INSPIRE directive.

  5. Ultrasensitive Analyzer for Realtime, In-Situ Airborne and Terrestrial Measurements of OCS, CO2, CO, and H2O

    NASA Astrophysics Data System (ADS)

    Provencal, R. A.; Gupta, M.; Baer, D. S.; Genty, B.

    2012-12-01

    Extensive research has suggested that OCS plays a critical role in Earth's environment. Due to its long atmospheric lifetime of ~ 35 years, OCS is the most abundant sulfur gas in the atmosphere and has been implicated in controlling the sulfur budget and aerosol loading of the stratosphere with tropical stratospheric levels exceeding 400 pptv as determined by remote satellite sensing. During volcanically-quiet periods, OCS is primarily responsible for the stratospheric aerosol layer, and flight data suggests that OCS may be used as an inverse tracer for biogenic volatile organic carbon compounds, including those thought to be responsible for the formation of secondary organic aerosols. Additionally, since the primary source and sink of non-anthropogenic OCS are considered to be the ocean emission and terrestrial vegetation uptake respectively, preliminary experimental and modeling studies have suggested that OCS/CO2 ratios may provide a tool to measure photosynthesis and help distinguish it from respiration. These results, and other similar data, have led researchers to propose that simultaneous measurements of OCS and CO2 can constrain the parameterizations of respiration and photosynthesis in carbon cycle models, and OCS gradients in the continental growing season may have broad use as a measurement-based tracer of photosynthesis. Despite the importance of carbonyl sulfide in atmospheric processes, the OCS atmospheric budget is poorly determined. Its primary sources are ocean outgassing, industrial processes (many of which produce CS2 that then oxidized into OCS), and biomass burning. Its primary sinks are vegetation and soils. However, the budget is poorly balanced with very high uncertainty. Improved, in-situ terrestrial flux and airborne measurements of OCS are required to improve this budget and further elucidate its role in stratospheric aerosol formation and as a tracer for biogenic volatile organics and photosynthesis. In this work, we have fabricated a

  6. Use of In Situ and Airborne Multiangle Data to Assess MODIS- and Landsat-based Estimates of Surface Albedo

    NASA Technical Reports Server (NTRS)

    Roman, Miguel O.; Gatebe, Charles K.; Shuai, Yanmin; Wang, Zhuosen; Gao, Feng; Masek, Jeff; Schaaf, Crystal B.

    2012-01-01

    The quantification of uncertainty of global surface albedo data and products is a critical part of producing complete, physically consistent, and decadal land property data records for studying ecosystem change. A current challenge in validating satellite retrievals of surface albedo is the ability to overcome the spatial scaling errors that can contribute on the order of 20% disagreement between satellite and field-measured values. Here, we present the results from an uncertain ty analysis of MODerate Resolution Imaging Spectroradiometer (MODIS) and Landsat albedo retrievals, based on collocated comparisons with tower and airborne multi-angular measurements collected at the Atmospheric Radiation Measurement Program s (ARM) Cloud and Radiation Testbed (CART) site during the 2007 Cloud and Land Surface Interaction Campaign (CLAS33 IC 07). Using standard error propagation techniques, airborne measurements obtained by NASA s Cloud Absorption Radiometer (CAR) were used to quantify the uncertainties associated with MODIS and Landsat albedos across a broad range of mixed vegetation and structural types. Initial focus was on evaluating inter-sensor consistency through assessments of temporal stability, as well as examining the overall performance of satellite-derived albedos obtained at all diurnal solar zenith angles. In general, the accuracy of the MODIS and Landsat albedos remained under a 10% margin of error in the SW(0.3 - 5.0 m) domain. However, results reveal a high degree of variability in the RMSE (root mean square error) and bias of albedos in both the visible (0.3 - 0.7 m) and near-infrared (0.3 - 5.0 m) broadband channels; where, in some cases, retrieval uncertainties were found to be in excess of 20%. For the period of CLASIC 07, the primary factors that contributed to uncertainties in the satellite-derived albedo values include: (1) the assumption of temporal stability in the retrieval of 500 m MODIS BRDF values over extended periods of cloud

  7. An Airborne Infrared Spectrometer for Solar Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Samra, Jenna; DeLuca, Edward E.; Golub, Leon; Cheimets, Peter; Philip, Judge

    2016-05-01

    The airborne infrared spectrometer (AIR-Spec) is an innovative solar spectrometer that will observe the 2017 solar eclipse from the NSF/NCAR High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER). AIR-Spec will image five infrared coronal emission lines to determine whether they may be useful probes of coronal magnetism.The solar magnetic field provides the free energy that controls coronal heating, structure, and dynamics. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections and ultimately drives space weather. Therefore, direct coronal field measurements have significant potential to enhance understanding of coronal dynamics and improve solar forecasting models. Of particular interest are observations of field lines in the transitional region between closed and open flux systems, providing important information on the origin of the slow solar wind.While current instruments routinely observe only the photospheric and chromospheric magnetic fields, AIR-Spec will take a step toward the direct observation of coronal fields by measuring plasma emission in the infrared at high spatial and spectral resolution. During the total solar eclipse of 2017, AIR-Spec will observe five magnetically sensitive coronal emission lines between 1.4 and 4 µm from the HIAPER Gulfstream V at an altitude above 14.9 km. The instrument will measure emission line intensity, width, and Doppler shift, map the spatial distribution of infrared emitting plasma, and search for waves in the emission line velocities.AIR-Spec consists of an optical system (feed telescope, grating spectrometer, and infrared detector) and an image stabilization system, which uses a fast steering mirror to correct the line-of-sight for platform perturbations. To ensure that the instrument meets its research goals, both systems are undergoing extensive performance modeling and testing. These results are shown with reference to the science requirements.

  8. Airborne stratospheric observations of major volcanic eruptions: past and future

    NASA Astrophysics Data System (ADS)

    Newman, P. A.; Aquila, V.; Colarco, P. R.

    2015-12-01

    Major volcanic eruptions (e.g. the 1991 eruption of Mt. Pinatubo) lead to a surface cooling and disruptions of the chemistry of the stratosphere. In this presentation, we will show model simulations of Mt. Pinatubo that can be used to devise a strategy for answering specific science questions. In particular, what is the initial mass injection, how is the cloud spreading, how are the stratospheric aerosols evolving, what is the impact on stratospheric chemistry, and how will climate be affected? We will also review previous stratospheric airborne observations of volcanic clouds using NASA sub-orbital assets, and discuss our present capabilities to observe the evolution of a stratospheric volcanic plume. These capabilities include aircraft such as the NASA ER-2, WB-57f, and Global Hawk. In addition, the NASA DC-8 and P-3 can be used to perform remote sensing. Balloon assets have also been employed, and new instrumentation is now available for volcanic work.

  9. Airborne in situ vertical profiling of HDO/H216O in the subtropical troposphere during the MUSICA remote sensing validation campaign

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Sanati, S.; Christner, E.; Zahn, A.; Balzer, M.; Bouquet, H.; McManus, J. B.; González-Ramos, Y.; Schneider, M.

    2015-01-01

    Vertical profiles of water vapor (H2O) and its isotope ratio D / H expressed as δ D(H2O were measured in situ by the ISOWAT II diode-laser spectrometer during the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA) airborne campaign. We present recent modifications of the instrument design. The instrument calibration on the ground as well as in flight is described. Based on the calibration measurements, the humidity-dependent uncertainty of our airborne data is determined. For the majority of the airborne data we achieved an accuracy (uncertainty of the mean) of Δ(δ D) ≈ 10‰. Vertical profiles between 150 and ~7000 m were obtained during 7 days in July and August 2013 over the subtropical North Atlantic Ocean near Tenerife. The flights were coordinated with ground-based (Network for the Detection of Atmospheric Composition Change, NDACC) and space-based (Infrared Atmospheric Sounding Interferometer, IASI) FTIR remote-sensing measurements of δ D(H2O) as a means to validate the remote sensing humidity and δ D(H2O) data products. The results of the validation are presented in detail in a separate paper (Schneider et al., 2014). The profiles were obtained with a high vertical resolution of around 3 m. By analyzing humidity and δ D(H2O) correlations we were able to identify different layers of airmasses with specific isotopic signatures. The results are discussed.

  10. Airborne in situ vertical profiling of HDO / H216O in the subtropical troposphere during the MUSICA remote sensing validation campaign

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Sanati, S.; Christner, E.; Zahn, A.; Balzer, M.; Bouquet, H.; McManus, J. B.; Gonzalez-Ramos, Y.; Schneider, M.

    2015-05-01

    Vertical profiles of water vapor (H2O) and its isotope ratio D / H expressed as δD(H2O) were measured in situ by the ISOWAT II diode-laser spectrometer during the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA) airborne campaign. We present recent modifications of the instrument design. The instrument calibration on the ground as well as in flight is described. Based on the calibration measurements, the humidity-dependent uncertainty of our airborne data is determined. For the majority of the airborne data we achieved an accuracy (uncertainty of the mean) of Δ(δD) ≈10‰. Vertical profiles between 150 and ~7000 m were obtained during 7 days in July and August 2013 over the subtropical North Atlantic Ocean near Tenerife. The flights were coordinated with ground-based (Network for the Detection of Atmospheric Composition Change, NDACC) and space-based (Infrared Atmospheric Sounding Interferometer, IASI) FTIR remote sensing measurements of δD(H2O) as a means to validate the remote sensing humidity and δD(H2O) data products. The results of the validation are presented in detail in a separate paper (Schneider et al., 2014). The profiles were obtained with a high vertical resolution of around 3 m. By analyzing humidity and δD(H2O) correlations we were able to identify different layers of air masses with specific isotopic signatures. The results are discussed.

  11. In-situ Observation and Differential Thermal Analysis of MnBi in High Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Miyazaki, Daiki; Mitsui, Yoshifuru; Abematsu, Ken-ichi; Takahashi, Kohki; Watanabe, Kazuo; Uda, Satoshi; Koyama, Keiichi

    For investigating in-field process of melting and solidification visually and quantitatively, in-situ observation system with differential thermal analysis (DTA) utilized in high temperature and in high magnetic field was developed. Decomposition processes of the bulk sample of ferromagnetic MnBi were directly observed with collecting DTA data under high magnetic field of 10 T for the 290-770 K temperature range. When the temperature was over decomposition point (ferromagnetic MnBi → paramagnetic Mn1.08Bi + liquid), liquid phase appeared on the sample surface. Furthermore, when the temperature was over peritectic temperature (∼ 700 K: paramagnetic Mn1.08Bi → Mn + liquid), the sample surface was broken and a large quantity of the liquid phase appeared from the sample. The in-situ observation also suggested that the decomposition temperature increased from 620 K for a zero field to 638 K for a magnetic field of 10 T.

  12. A Comparison of Aerosol Properties Derived by Remote Sensing and in-situ Observations

    NASA Astrophysics Data System (ADS)

    Ricchiazzi, P.; Gautier, C.

    2002-12-01

    In-situ measurements of aerosol scattering properties obtained by the Aerosol Observing System (AOS) at the ARM CART site are compared to remote sensing estimates, based on irradiance observations from a Multi Filter Rotating Shadowband Radiometer (MFRSR) and radiance measurements from the Whole Sky Imager (WSI). The statistical relationship between the in-situ and remote-sensing parameters are determined at set of selected times with similar surface weather conditions (wind velocity, relative humidity, temperature etc.) One of the main goals of this project is to determine if variations in measured clear-sky radiation correlate with the variability seen by the ground-based AOS. Since the AOS is part of the very wide spread AERONET observational network, such a connection, if it exists, will help explain how global trends in aerosol production and transport will affect the global radiative energy budget.

  13. Influence of solar-probe inherent atmosphere on in-situ observations

    SciTech Connect

    Hassanein, A.; Konkashbaev, A.I.; Konkashbaev, I.K.; Nikandrov, L.B.

    1998-08-01

    The solar corona is the source of the solar wind, which is responsible for the heliosphere and plays a crucial role in solar/terrestrial phenomena. A comprehensive understanding of these phenomena can be established only by directly measuring ion and electron velocity distributions, plasma waves, and fluxes of energetic particles near the sun. The problem resulting from the inherent atmosphere of a spacecraft moving in the vicinity of the sun and the influence of this atmosphere on in-situ measurements of the solar corona plasma is key to the realization and success of any solar probe mission. To evaluate the influence of the probe-inherent atmosphere on in-situ observations, the authors have developed comprehensive radiation hydrodynamic models. The physics of plasma/probe/vapor interaction are also being developed in a self-consistent model to predict the effect of probe inherent atmosphere on in-situ measurements of corona parameters during solar flares. Interaction of the ionized atmosphere with the ambient natural plasma will create a turbulent shock wave that can affect in-situ measurements and must be taken into account in designing the spacecraft and its scientific components.

  14. Cumulus convection as observed from an airborne infrared radiometer

    NASA Technical Reports Server (NTRS)

    Szejwach, G.; Simpson, J.

    1982-01-01

    The implementation of high resolution passive radiative remote sensing of the cloudiness volume in the atmospheric window between 10.5-12.5 microns is described. Airborne radiometers, the NASA/Cloud Top Scanner, were used to obtain radiances during several passages over two merging cumulus clouds, with the data being converted into equivalent blackbody temperatures. Data were also gathered in the 0.55-0.70 micron visible bands as part of the SESAME-79 experiment. The number of points observed in the IR channel were adjusted to account for the viewing angle and areal extents were calculated. A relationship was assumed to exist between the brightness temperatures of the cloud surface and the level of cloudiness at a given atmospheric altitude. Further measurements with lidar scans are indicated in order to reduce the error levels associated with the method.

  15. Ice surface temperatures: seasonal cycle and daily variability from in-situ and satellite observations

    NASA Astrophysics Data System (ADS)

    Madsen, Kristine S.; Dybkjær, Gorm; Høyer, Jacob L.; Nielsen-Englyst, Pia; Rasmussen, Till A. S.; Tonboe, Rasmus T.

    2016-04-01

    Surface temperature is an important parameter for understanding the climate system, including the Polar Regions. Yet, in-situ temperature measurements over ice- and snow covered regions are sparse and unevenly distributed, and atmospheric circulation models estimating surface temperature may have large biases. To change this picture, we will analyse the seasonal cycle and daily variability of in-situ and satellite observations, and give an example of how to utilize the data in a sea ice model. We have compiled a data set of in-situ surface and 2 m air temperature observations over land ice, snow, sea ice, and from the marginal ice zone. 2523 time series of varying length from 14 data providers, with a total of more than 13 million observations, have been quality controlled and gathered in a uniform format. An overview of this data set will be presented. In addition, IST satellite observations have been processed from the Metop/AVHRR sensor and a merged analysis product has been constructed based upon the Metop/AVHRR, IASI and Modis IST observations. The satellite and in-situ observations of IST are analysed in parallel, to characterize the IST variability on diurnal and seasonal scales and its spatial patterns. The in-situ data are used to estimate sampling effects within the satellite observations and the good coverage of the satellite observations are used to complete the geographical variability. As an example of the application of satellite IST data, results will be shown from a coupled HYCOM-CICE ocean and sea ice model run, where the IST products have been ingested. The impact of using IST in models will be assessed. This work is a part of the EUSTACE project under Horizon 2020, where the ice surface temperatures form an important piece of the puzzle of creating an observationally based record of surface temperatures for all corners of the Earth, and of the ESA GlobTemperature project which aims at applying surface temperatures in models in order to

  16. Challenges in the Management and Stewardship of Airborne Observational Data at the National Center for Atmospheric Research (NCAR) Earth Observing Laboratory (EOL)

    NASA Astrophysics Data System (ADS)

    Aquino, J.; Daniels, M. D.

    2015-12-01

    The National Science Foundation (NSF) provides the National Center for Atmospheric Research (NCAR) Earth Observing Laboratory (EOL) funding for the operation, maintenance and upgrade of two research aircraft: the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) Gulfstream V and the NSF/NCAR Hercules C-130. A suite of in-situ and remote sensing airborne instruments housed at the EOL Research Aviation Facility (RAF) provide a basic set of measurements that are typically deployed on most airborne field campaigns. In addition, instruments to address more specific research requirements are provided by collaborating participants from universities, industry, NASA, NOAA or other agencies (referred to as Principal Investigator, or PI, instruments). At the 2014 AGU Fall Meeting, a poster (IN13B-3639) was presented outlining the components of Airborne Data Management included field phase data collection, formats, data archival and documentation, version control, storage practices, stewardship and obsolete data formats, and public data access. This talk will cover lessons learned, challenges associated with the above components, and current developments to address these challenges, including: tracking data workflows for aircraft instrumentation to facilitate identification, and correction, of gaps in these workflows; implementation of dataset versioning guidelines; and assignment of Digital Object Identifiers (DOIs) to data and instrumentation to facilitate tracking data and facility use in publications.

  17. Direct in situ observations of single Fe atom catalytic processes and anomalous diffusion at graphene edges.

    PubMed

    Zhao, Jiong; Deng, Qingming; Avdoshenko, Stanislav M; Fu, Lei; Eckert, Jürgen; Rümmeli, Mark H

    2014-11-04

    Single-atom catalysts are of great interest because of their high efficiency. In the case of chemically deposited sp(2) carbon, the implementation of a single transition metal atom for growth can provide crucial insight into the formation mechanisms of graphene and carbon nanotubes. This knowledge is particularly important if we are to overcome fabrication difficulties in these materials and fully take advantage of their distinct band structures and physical properties. In this work, we present atomically resolved transmission EM in situ investigations of single Fe atoms at graphene edges. Our in situ observations show individual iron atoms diffusing along an edge either removing or adding carbon atoms (viz., catalytic action). The experimental observations of the catalytic behavior of a single Fe atom are in excellent agreement with supporting theoretical studies. In addition, the kinetics of Fe atoms at graphene edges are shown to exhibit anomalous diffusion, which again, is in agreement with our theoretical investigations.

  18. In situ observation of mechanical damage within a SiC-SiC ceramic matrix composite

    NASA Astrophysics Data System (ADS)

    Saucedo-Mora, L.; Lowe, T.; Zhao, S.; Lee, P. D.; Mummery, P. M.; Marrow, T. J.

    2016-12-01

    SiC-SiC ceramic matrix composites are candidate materials for fuel cladding in Generation IV nuclear fission reactors and as accident tolerant fuel clad in current generation plant. Experimental methods are needed that can detect and quantify the development of mechanical damage, to support modelling and qualification tests for these critical components. In situ observations of damage development have been obtained of tensile and C-ring mechanical test specimens of a braided nuclear grade SiC-SiC ceramic composite tube, using a combination of ex situ and in situ computed X-ray tomography observation and digital volume correlation analysis. The gradual development of damage by matrix cracking and also the influence of non-uniform loading are examined.

  19. High resolution transmission electron microscopic in-situ observations of plastic deformation of compressed nanocrystalline gold

    SciTech Connect

    Wang, Guoyong; Lian, Jianshe; Jiang, Qing; Sun, Sheng; Zhang, Tong-Yi

    2014-09-14

    Nanocrystalline (nc) metals possess extremely high strength, while their capability to deform plastically has been debated for decades. Low ductility has hitherto been considered an intrinsic behavior for most nc metals, due to the lack of five independent slip systems actively operating during deformation in each nanograin. Here we report in situ high resolution transmission electron microscopic (HRTEM) observations of deformation process of nc gold under compression, showing the excellent ductility of individual and aggregate nanograins. Compression causes permanent change in the profile of individual nanograins, which is mediated by dislocation slip and grain rotation. The high rate of grain boundary sliding and large extent of widely exited grain rotation may meet the boundary compatibility requirements during plastic deformation. The in situ HRTEM observations suggest that nc gold is not intrinsically brittle under compressive loading.

  20. In situ observation of optomechanical Bloch oscillations in an optical cavity

    NASA Astrophysics Data System (ADS)

    Keßler, H.; Klinder, J.; Prasanna Venkatesh, B.; Georges, Ch; Hemmerich, A.

    2016-10-01

    It is shown experimentally that a Bose-Einstein condensate inside an optical cavity, operating in the regime of strong cooperative coupling, responds to an external force by an optomechanical Bloch oscillation, which can be directly observed in the light leaking out of the cavity. Previous theoretical work predicts that the frequency of this oscillation matches with that of conventional Bloch oscillations such that its in situ monitoring may help to increase the data acquisition speed in precision force measurements.

  1. Fusion of mobile in situ and satellite remote sensing observations of chemical release emissions to improve disaster response

    DOE PAGES

    Leifer, Ira; Melton, Christopher; Frash, Jason; ...

    2016-09-22

    Chemical release disasters have serious consequences, disrupting ecosystems, society, and causing significant loss of life. Mitigating the destructive impacts relies on identification and mapping, monitoring, and trajectory forecasting. Improvements in sensor capabilities are enabling airborne and space-based remote sensing to support response activities. Key applications are improving transport models in complex terrain and improved disaster response. Understanding urban atmospheric transport in the Los Angeles Basin, where topographic influences on transport patterns are significant, was improved by leveraging the Aliso Canyon leak as an atmospheric tracer. Plume characterization data was collected by the AutoMObile trace Gas (AMOG) Surveyor, a commuter carmore » modified for science. Mobile surface in situ CH4 and winds were measured by AMOG Surveyor under Santa Ana conditions to estimate an emission rate of 365±30% Gg yr-1. Vertical profiles were collected by AMOG Surveyor by leveraging local topography for vertical profiling to identify the planetary boundary layer at ~700 m. Topography significantly constrained plume dispersion by up to a factor of two. The observed plume trajectory was used to validate satellite aerosol optical depth-inferred atmospheric transport, which suggested the plume first was driven offshore, but then veered back towards land. Numerical long-range transport model predictions confirm this interpretation. Lastly, this study demonstrated a novel application of satellite aerosol remote sensing for disaster response.« less

  2. Deriving an atmospheric budget of total organic bromine using airborne in-situ measurements from the Western Pacific during SHIVA

    NASA Astrophysics Data System (ADS)

    Sala, S.; Bönisch, H.; Keber, T.; Oram, D. E.; Mills, G.; Engel, A.

    2014-02-01

    During the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project an extensive dataset of all halogen species relevant for the atmospheric budget of total organic bromine has been collected in the West Pacific region using the FALCON aircraft operated by the German Aerospace agency DLR (Deutsches Zentrum für Luft- und Raumfahrt) covering a vertical range from the planetary boundary layer up to the ceiling altitude of the aircraft of 13 km. In total, more than 700 measurements were performed with the newly developed fully-automated in-situ instrument GHOST-MS (Gas cHromatograph for the Observation of Tracers - coupled with a Mass Spectrometer) by the Goethe University of Frankfurt (GUF) and with the onboard whole-air sampler WASP with subsequent ground based state-of-the-art GC/MS analysis by the University of East Anglia (UEA). Both instruments yield good agreement for all major (CHBr3 and CH2Br2) and minor (CHBrCl, CHBrCl2 and CHBr2Cl) VSLS (very short-lived substances), at least at the level of their 2 σ measurement uncertainties. In contrast to the suggestion that the Western Pacific could be a major source region for VSLS (Pyle et al., 2011), we found only slightly enhanced mixing ratios of brominated halogen source gases relative to the levels reported in Montzka et al. (2011) for other tropical regions. A budget for total organic bromine, including all four halons,CH3Br and the VSLS, is derived for the upper troposphere, the input region for the TTL and thus also for the stratosphere, compiled from the SHIVA dataset. With exception of the two minor VSLS CHBrCl2 and CHBr2Cl, excellent agreement with the values reported in Montzka et al. (2011) is found, while being slightly higher than previous studies from our group based on balloon-borne measurements.

  3. Vortex dynamics behind cruising aircraft studied by a ground-based scanning lidar and airborne in-situ measurements

    NASA Astrophysics Data System (ADS)

    Sussmann, Ralf; Jaeger, Horst

    1997-05-01

    By LIDAR and CCD camera analysis the geometrical evolution of a vortex phase contrail (descent rate Vd equals 2.7 m/s, vortex separation D equals 47 m, vertical extension (sigma) z equals 140 m after 77 s) is analyzed. The contrail of a four-engine aircraft is showing a diffuse central wake phenomenon. From coincident in situ measurements all relevant meteorological parameters are characterized. Ambient humidity had been close to ice saturation. From this a non-exhaust formation of ice can be excluded. Also the mechanism of non- entrainment of exhaust into the vortices is excluded of being responsible for the observed early onset of the central wake (870 m behind aircraft). The central wake onset originates from early detrainment starting after a 3/4 roll-up period of the vortex. Baroclinic and shear forces do not contribute to the detrainment (imaginary Brunt-Vaisala-frequency N2 equals negative 3 multiplied by 10-5 s-2, shear dS/dz equals negative 0.01 s-1, bulk Richardson number Ri, equals N2/(dS/dz)2 equals negative 0.3). Ambient turbulence had been fully developed with an inertial range and locally isotropic turbulence for wavenumbers k-equals 0.004 - 0.1 radian/m. The eddy dissipation rate (epsilon) equals 7.4 plus or minus 0.5 multiplied by 10-5 m2s-3 exceeds the values found over the North Atlantic flight corridor at cruising altitude by a factor of 1000. Turbulence was identified as the dominating detrainment mechanism.

  4. Fast-response airborne in situ measurements of HNO3 during the Texas 2000 Air Quality Study

    NASA Astrophysics Data System (ADS)

    Neuman, J. A.; Huey, L. G.; Dissly, R. W.; Fehsenfeld, F. C.; Flocke, F.; Holecek, J. C.; Holloway, J. S.; Hübler, G.; Jakoubek, R.; Nicks, D. K.; Parrish, D. D.; Ryerson, T. B.; Sueper, D. T.; Weinheimer, A. J.

    2002-10-01

    Nitric acid (HNO3) was measured from an aircraft in the planetary boundary layer and free troposphere up to 7 km on 14 flights during the Texas Air Quality Study in August and September 2000. HNO3 mixing ratios were measured at 1 Hz using a fast-response chemical ionization mass spectrometer with SiF5- reagent ions. HNO3 measurement using this highly selective ion chemistry is insensitive to water vapor and is not degraded by interferences from other species. Rapid time response (1 s) was achieved using a heated Teflon inlet. In-flight standard addition calibrations from a HNO3 permeation source were used to determine the instrument sensitivity of 1.1 ± 0.1 ion counts pptv-1 s-1 over the duration of the study. Contributions to the HNO3 signal from instrument artifacts were accounted for by regularly performing in-flight instrument background checks, where HNO3 was removed from the ambient air sample by diverting the sampled air though a nylon wool scrubber. Measurement inaccuracy, which is determined from uncertainties in the standard addition calibrations, was ±10%. Measurement precision at low HNO3 levels was ±25 pptv (1σ) for the 1 Hz data and ±9 pptv for 10 s averages of the 1 s measurements. Coincident in situ measurements of other reactive nitrogen species are used to examine NOy partitioning and HNO3 formation during this month long measurement campaign. The sum of the individually measured reactive nitrogen species is shown to be in agreement with the measured NOy. HNO3 formation in plumes from electric utility power plants, urban areas, and petrochemical facilities was studied. The observed differences in the fractional contribution of HNO3 to NOy in plumes from different anthropogenic source types are discussed.

  5. Airborne In-Situ Measurements of Formaldehyde over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    NASA Technical Reports Server (NTRS)

    Marrero, Josette; St. Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  6. Airborne In-Situ Measurements of Formaldehyde Over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    NASA Technical Reports Server (NTRS)

    Marrero, Josette Elizabeth; Saint Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  7. Comparisons of Anvil Cirrus Spatial Characteristics between Airborne Observations in DC3 Campaign and WRF Simulations

    NASA Astrophysics Data System (ADS)

    D'Alessandro, J.; Diao, M.; Chen, M.

    2015-12-01

    John D'Alessandro1, Minghui Diao1, Ming Chen2, George Bryan2, Hugh Morrison21. Department of Meteorology and Climate Science, San Jose State University2. Mesoscale & Microscale Meteorology Division, National Center for Atmospheric Research, Boulder, CO, 80301 Ice crystal formation requires the prerequisite condition of ice supersaturation, i.e., relative humidity with respect to ice (RHi) greater than 100%. The formation and evolution of ice supersaturated regions (ISSRs) has large impact on the subsequent formation of ice clouds. To examine the characteristics of simulated ice supersaturated regions at various model spatial resolutions, case studies between airborne in-situ measurements in the NSF Deep Convective, Clouds and Chemistry (DC3) campaign (May - June 2012) and WRF simulations are conducted in this work. Recent studies using ~200 m in-situ observations showed that ice supersaturated regions are mostly around 1 km in horizontal scale (Diao et al. 2014). Yet it is still unclear if such observed characteristics can be represented by WRF simulations at various spatial resolutions. In this work, we compare the WRF simulated anvil cirrus spatial characteristics with those observed in the DC3 campaign over the southern great plains in US. The WRF model is run at 1 km and 3 km horizontal grid spacing with a recent update of Thompson microphysics scheme. Our comparisons focus on the spatial characteristics of ISSRs and cirrus clouds, including the distributions of their horizontal scales, the maximum relative humidity with respect to ice (RHi) and the relationship between RHi and temperature. Our previous work on the NCAR CM1 cloud-resolving model shows that the higher resolution runs (i.e., 250m and 1km) generally have better agreement with observations than the coarser resolution (4km) runs. We will examine if similar trend exists for WRF simulations in deep convection cases. In addition, we will compare the simulation results between WRF and CM1, particularly

  8. Airborne lidar observations of cirrus clouds in the Tropics, Mid-latitudes, and the Arctic

    NASA Astrophysics Data System (ADS)

    Ismail, S.; Browell, E.; Ferrare, R.; Grant, W.; Kooi, S.; Brackett, V.; Mahoney, M.

    2003-04-01

    Airborne lidar systems have demonstrated an unsurpassed capability to detect and profile optically thin cirrus. The airborne Lidar Atmospheric Sensing Experiment (LASE) has demonstrated a capability to detect thin cirrus at aerosol scattering levels of <2.0× 10-9 m-1 sr-1 at 815 nm, and this makes it well suited for deriving many cirrus cloud properties. LASE has been operated from high- and medium-altitude aircraft and has participated in 9 major field experiments over the past 8 years. During these missions, data were collected related to optically thin cirrus and moisture in the upper troposphere in the tropics, mid- and high-latitudes. LASE data from these field experiments have been used to characterize the cirrus as thin laminae, thick cirrus, deep convective cirrus, and cirrus anvils. In addition, characteristics including the cloud top height, optical depth, aerosol scattering ratio, lidar extinction-to-backscatter ratio have been derived for optically thin cirrus. During these field experiments, many data sets were available to interpret the cirrus cloud properties including data from satellites, in situ temperature and moisture instruments on aircraft, radiosondes, and during some field experiments, the Microwave Temperature Profiler (MTP). LASE data from long-range flights have been used to derive a relationship between the latitudinal variation of cloud top heights and tropopause locations. These measurements were also used to examine the relationship between relative humidity and the presence of cirrus. LASE observations of cirrus clouds and water vapor fields have also been used to identify dynamical processes like stratosphere-troposphere exchange and to study their characteristics. Examples of these observations and analyses are presented to demonstrate the advantage of using LASE measurements for conducting atmospheric science investigations.

  9. Evaluation of NOx emission inventories in California using multi-satellite data sets, AMAX-DOAS and in-situ airborne measurements, and regional model simulations during the CalNex field campaign

    NASA Astrophysics Data System (ADS)

    Kim, S.; Baidar, S.; Boersma, F.; Brioude, J.; Bucsela, E. J.; Burrows, J. P.; Celarier, E. A.; Cohen, R. C.; Frost, G. J.; Krotkov, N. A.; Lamsal, L. N.; Martin, R. V.; McKeen, S. A.; Oetjen, H.; Pollack, I. B.; Richter, A.; Russell, A. R.; Ryerson, T. B.; Trainer, M.; Valin, L. C.; Volkamer, R. M.

    2012-12-01

    Satellite NO2 column measurements indicate large NOx emissions from urban and agricultural sources in California. In this presentation, we highlight the NOx sources identified in California using the satellite measurements. Comparison of regional model-simulated NO2 columns with satellite retrievals has proven useful in evaluating emission inventories for various sectors. We compare the NO2 columns from the WRF-Chem model with the multi-satellite data sets from different instruments and retrieval groups for a variety of California sources. Use of multiple satellite data sets help to define the uncertainties in the satellite retrievals. In addition, the CalNex 2010 intensive field campaign provides a unique opportunity to independently assess California's emission inventories. CU-AMAX-DOAS and in-situ airborne observations from CalNex 2010 and fine-resolution model simulations are used to estimate the accuracy of the satellite NO2 column retrievals.

  10. Size Dependent Pore Formation in Germanium Nanowires Undergoing Reversible Delithiation Observed by In Situ TEM

    SciTech Connect

    Lu, Xiaotang; He, Yang; Mao, Scott X.; Wang, Chong-min; Korgel, Brian A.

    2016-12-22

    Germanium (Ge) nanowires coated with an amorphous silicon (Si) shell undergoing lithiation and delithiation were studied using in situ transmission electron microscopy (TEM). Delithiation creates pores in nanowires with diameters larger than ~25 nm, but not in smaller diameter nanowires. The formation of pores in Ge nanowires undergoing delithiation has been observed before in in situ TEM experiments, but there has been no indication that a critical diameter exists below which pores do not form. Pore formation occurs as a result of fast lithium diffusion compared to vacancy migration. We propose that a short diffusion path for vacancies to the nanowire surface plays a role in limiting pore formation even when lithium diffusion is fast.

  11. In-Situ atomic force microscopic observation of ion beam bombarded plant cell envelopes

    NASA Astrophysics Data System (ADS)

    Sangyuenyongpipat, S.; Yu, L. D.; Brown, I. G.; Seprom, C.; Vilaithong, T.

    2007-04-01

    A program in ion beam bioengineering has been established at Chiang Mai University (CMU), Thailand, and ion beam induced transfer of plasmid DNA molecules into bacterial cells (Escherichia coli) has been demonstrated. However, a good understanding of the fundamental physical processes involved is lacking. In parallel work, onion skin cells have been bombarded with Ar+ ions at energy 25 keV and fluence1-2 × 1015 ions/cm2, revealing the formation of microcrater-like structures on the cell wall that could serve as channels for the transfer of large macromolecules into the cell interior. An in-situ atomic force microscope (AFM) system has been designed and installed in the CMU bio-implantation facility as a tool for the observation of these microcraters during ion beam bombardment. Here we describe some of the features of the in-situ AFM and outline some of the related work.

  12. Calculated in situ rock density from gravity observations, UA-1 (Cannikin) emplacement hole, Amchitka Island, Alaska

    USGS Publications Warehouse

    Healey, D.L.

    1971-01-01

    Gravity observations were made on the ground surface and at a depth of 5,854 feet in drill hole UA-1. Two attempts to measure the free-air gradient utilizing the headframe over the drill hole were unsuccessful owing to mechanical vibrations in the structure. Because of the uncertainty in the measured free-air gradients these values were discarded and the average value (0.09406 mgal/ft) was used in the calculations. The calculated in situ bulk density is 2.36 g/cc. The weighted average bulk density determined from 47 core samples taken in the adjacent UAE-1 drill hole is also 2.36 g/cc. An analysis of selected portions of density logs provides an in situ bulk density of 2.37 g/cc.

  13. Corrosion of nickel metal by hydrothermal sodium tungstate solution observed by in-situ infrared spectroscopy

    SciTech Connect

    Hoffmann, M.M.; Fulton, J.L.

    2000-05-01

    Corrosion of nickel metal in a high-temperature aqueous tungstate solution was described. The corrosion altered the solution's pH, which affected the equilibrium of the solution chemistry. These secondary effects of the corrosion process were observed with in-situ infrared (IR) spectroscopy, demonstrating that important information on corrosion phenomena at the solid-fluid interface may be obtained from in-situ spectroscopic studies of the fluid phase. Subsequent scanning electron microscopy (SEM) analysis of the corroded nickel metal and solid corrosion products support conclusions drawn from solution chemistry measurements. The presented findings are of interest to researchers and engineers that use pure nickel or nickel-bearing alloys as a material for high-temperature, high-pressure applications in aqueous solutions.

  14. In situ observation of electrolyte-concentration-dependent solid electrolyte interphase on graphite in dimethyl sulfoxide.

    PubMed

    Liu, Xing-Rui; Wang, Lin; Wan, Li-Jun; Wang, Dong

    2015-05-13

    High lithium salt concentration strategy has been recently reported to be an effective method to enable various organic solvents as electrolyte of Li-ion batteries. Here, we utilize in situ atomic force microscopy (AFM) to investigate the interfacial morphology on the graphite electrode in dimethyl sulfoxide (DMSO)-based electrolyte of various concentrations. The significant differences in interfacial features of the graphite in electrolytes of different concentrations are revealed. In the concentrated electrolyte, stable films form primarily at the step edges and defects on the graphite surface after initial electrochemical cycling. On the other hand, in the dilute electrolyte, DMSO-solvated lithium ions constantly intercalate into graphite layers, and serious decomposition of solvent accompanied by structural deterioration of the graphite surface is observed. The in situ AFM results provide direct evidence for the concentration-dependent interface reactions between graphite electrode and DMSO-based electrolyte.

  15. Deriving an atmospheric budget of total organic bromine using airborne in situ measurements from the western Pacific area during SHIVA

    NASA Astrophysics Data System (ADS)

    Sala, S.; Bönisch, H.; Keber, T.; Oram, D. E.; Mills, G.; Engel, A.

    2014-07-01

    During the recent SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project an extensive data set of all halogen species relevant for the atmospheric budget of total organic bromine was collected in the western Pacific region using the Falcon aircraft operated by the German Aerospace agency DLR (Deutsches Zentrum für Luft- und Raumfahrt) covering a vertical range from the planetary boundary layer up to the ceiling altitude of the aircraft of 13 km. In total, more than 700 measurements were performed with the newly developed fully automated in situ instrument GHOST-MS (Gas chromatograph for the Observation of Tracers - coupled with a Mass Spectrometer) by the Goethe University of Frankfurt (GUF) and with the onboard whole-air sampler WASP with subsequent ground-based state-of-the-art GC / MS analysis by the University of East Anglia (UEA). Both instruments yield good agreement for all major (CHBr3 and CH2Br2) and minor (CH2BrCl, CHBrCl2 and CHBr2Cl) VSLS (very short-lived substances), at least at the level of their 2σ measurement uncertainties. In contrast to the suggestion that the western Pacific could be a region of strongly increased atmospheric VSLS abundance (Pyle et al., 2011), we found only in the upper troposphere a slightly enhanced amount of total organic bromine from VSLS relative to the levels reported in Montzka and Reimann et al. (2011) for other tropical regions. From the SHIVA observations in the upper troposphere, a budget for total organic bromine, including four halons (H-1301, H-1211, H-1202, H-2402), CH3Br and the VSLS, is derived for the level of zero radiative heating (LZRH), the input region for the tropical tropopause layer (TTL) and thus also for the stratosphere. With the exception of the two minor VSLS CHBrCl2 and CHBr2Cl, excellent agreement with the values reported in Montzka and Reimann et al. (2011) is found, while being slightly higher than previous studies from our group based on balloon-borne measurements.

  16. Long-term groundwater storage change in Victoria, Australia from satellite gravity and in situ observations

    NASA Astrophysics Data System (ADS)

    Chen, J.

    2015-12-01

    Analyses based on satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) and land surface model data indicate that groundwater storage in Victoria, Australia had been declining steadily, until a trend reversal around early 2010, attributed to two wetter seasons in 2010 and 2011. In situ groundwater level measurements (from a network of 1395 bores in Victoria) also indicate a steady groundwater depletion since early 90's, and show remarkable agreement with GRACE estimates for the 10-year period (2003-2012) in common with the GRACE mission. Groundwater depletion rates for 2005 to 2009 are relatively large as indicated by both GRACE estimates (8.0 ± 1.7 km3/yr) and in situ measurements (8.3 ± 3.4 km3/yr). Over the same period (2005-2009), GRACE measurements capture significant groundwater depletion in a wider region covering much of the southern Murray-Darling Basin, and the total groundwater depletion rate in this region is about 17.2 ± 4.7 km3/yr. Annual groundwater storage changes are strongly correlated with precipitation anomalies, but magnitudes of anomalous precipitation and groundwater storage suggest that only about one-fifth of anomalous precipitation contributes to groundwater recharge. The strong correlation suggests that this significant groundwater depletion is primarily related to drought (plus groundwater pumping for agricultural and domestic consumption). This study shows the importance of reducing leakage bias in GRACE observations through post data processings. The remarkable agreement between GRACE estimates and in situ measurements demonstrates the great potentials of using satellite gravity observations in combination with land surface model estimates to quantify changes in regional groundwater resources, especially when in situ measurements are limited or unavailable.

  17. In Situ Observations of Phase Transitions in Metastable Nickel (Carbide)/Carbon Nanocomposites.

    PubMed

    Bayer, Bernhard C; Bosworth, David A; Michaelis, F Benjamin; Blume, Raoul; Habler, Gerlinde; Abart, Rainer; Weatherup, Robert S; Kidambi, Piran R; Baumberg, Jeremy J; Knop-Gericke, Axel; Schloegl, Robert; Baehtz, Carsten; Barber, Zoe H; Meyer, Jannik C; Hofmann, Stephan

    2016-10-06

    Nanocomposite thin films comprised of metastable metal carbides in a carbon matrix have a wide variety of applications ranging from hard coatings to magnetics and energy storage and conversion. While their deposition using nonequilibrium techniques is established, the understanding of the dynamic evolution of such metastable nanocomposites under thermal equilibrium conditions at elevated temperatures during processing and during device operation remains limited. Here, we investigate sputter-deposited nanocomposites of metastable nickel carbide (Ni3C) nanocrystals in an amorphous carbon (a-C) matrix during thermal postdeposition processing via complementary in situ X-ray diffractometry, in situ Raman spectroscopy, and in situ X-ray photoelectron spectroscopy. At low annealing temperatures (300 °C) we observe isothermal Ni3C decomposition into face-centered-cubic Ni and amorphous carbon, however, without changes to the initial finely structured nanocomposite morphology. Only for higher temperatures (400-800 °C) Ni-catalyzed isothermal graphitization of the amorphous carbon matrix sets in, which we link to bulk-diffusion-mediated phase separation of the nanocomposite into coarser Ni and graphite grains. Upon natural cooling, only minimal precipitation of additional carbon from the Ni is observed, showing that even for highly carbon saturated systems precipitation upon cooling can be kinetically quenched. Our findings demonstrate that phase transformations of the filler and morphology modifications of the nanocomposite can be decoupled, which is advantageous from a manufacturing perspective. Our in situ study also identifies the high carbon content of the Ni filler crystallites at all stages of processing as the key hallmark feature of such metal-carbon nanocomposites that governs their entire thermal evolution. In a wider context, we also discuss our findings with regard to the much debated potential role of metastable Ni3C as a catalyst phase in graphene and carbon

  18. In Situ Observations of Phase Transitions in Metastable Nickel (Carbide)/Carbon Nanocomposites

    PubMed Central

    2016-01-01

    Nanocomposite thin films comprised of metastable metal carbides in a carbon matrix have a wide variety of applications ranging from hard coatings to magnetics and energy storage and conversion. While their deposition using nonequilibrium techniques is established, the understanding of the dynamic evolution of such metastable nanocomposites under thermal equilibrium conditions at elevated temperatures during processing and during device operation remains limited. Here, we investigate sputter-deposited nanocomposites of metastable nickel carbide (Ni3C) nanocrystals in an amorphous carbon (a-C) matrix during thermal postdeposition processing via complementary in situ X-ray diffractometry, in situ Raman spectroscopy, and in situ X-ray photoelectron spectroscopy. At low annealing temperatures (300 °C) we observe isothermal Ni3C decomposition into face-centered-cubic Ni and amorphous carbon, however, without changes to the initial finely structured nanocomposite morphology. Only for higher temperatures (400–800 °C) Ni-catalyzed isothermal graphitization of the amorphous carbon matrix sets in, which we link to bulk-diffusion-mediated phase separation of the nanocomposite into coarser Ni and graphite grains. Upon natural cooling, only minimal precipitation of additional carbon from the Ni is observed, showing that even for highly carbon saturated systems precipitation upon cooling can be kinetically quenched. Our findings demonstrate that phase transformations of the filler and morphology modifications of the nanocomposite can be decoupled, which is advantageous from a manufacturing perspective. Our in situ study also identifies the high carbon content of the Ni filler crystallites at all stages of processing as the key hallmark feature of such metal–carbon nanocomposites that governs their entire thermal evolution. In a wider context, we also discuss our findings with regard to the much debated potential role of metastable Ni3C as a catalyst phase in graphene and

  19. Long-term groundwater storage change in Victoria, Australia from satellite gravity and in situ observations

    NASA Astrophysics Data System (ADS)

    Chen, J. L.; Wilson, C. R.; Tapley, B. D.; Scanlon, Bridget; Güntner, Andreas

    2016-04-01

    Analysis based on satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) and land surface models indicates that groundwater storage in Victoria, Australia had been declining steadily, until a trend reversal around early 2010, attributed to two wetter seasons in 2010 and 2011. In situ groundwater level measurements (from a network of 1395 bores in Victoria) also indicate a steady groundwater depletion since the early 1990's, and show remarkable agreement with GRACE estimates for the 10-year period (2003-2012) in common with the GRACE mission. Groundwater depletion rates for 2005 to 2009 are relatively large as indicated by both GRACE estimates (8.0 ± 1.7 km3/yr) and in situ measurements (8.3 ± 3.4 km3/yr). Over the same period (2005-2009), GRACE measurements capture significant groundwater depletion in a wider region covering much of the southern Murray-Darling Basin, and the total groundwater depletion rate in this region is about 17.2 ± 4.7 km3/yr. Annual groundwater storage changes are strongly correlated with precipitation anomalies, but only about one-fifth of anomalous precipitation contributes to groundwater recharge. The strong correlation suggests that this groundwater depletion is primarily related to drought with related groundwater pumping for agricultural and domestic consumption. The remarkable agreement between GRACE estimates and in situ measurements demonstrates the great potential of satellite gravity observations in combination with land surface model estimates to quantify changes in regional groundwater resources, especially when in situ measurements are limited or unavailable. This study shows the importance of reducing leakage bias in GRACE observations and the effectiveness of the forward modeling iterative method used.

  20. Comparing Temperature and Precipitation Extremes Across Multiple Reanalyses and Gridded in Situ Observational Datasets

    NASA Astrophysics Data System (ADS)

    Donat, M.; Alexander, L. V.; Sillmann, J.; Wild, S.; Zwiers, F. W.; Lippmann, T.

    2014-12-01

    Changes in climate extremes are often monitored using global gridded datasets of climate extremes based on in situ observations or reanalysis data. This study assesses the consistency of temperature and precipitation extremes between these datasets. We compare temporal evolution and spatial patterns of annual climate extremes indices across multiple global gridded datasets of in situ observations and reanalyses to make inferences on the robustness of the obtained results. While there are distinct differences in the actual values of extremes, normalized time series generally compare well and temporal correlations are high for temperature extremes, in particular for the most recent three decades when satellite data are available for assimilation. Extreme precipitation is characterized by higher temporal and spatial variability than extreme temperatures, and there is less agreement between different datasets than for temperature. However, reasonable agreement between gridded precipitation extremes from the different datasets remains. While there is general agreement between the different reanalyses and gridded observational data in regions with dense observational coverage, different reanalyses show trends of partly opposing signs in areas where in situ observations are sparse, e.g. over parts of Africa and tropical South America. However, in the absence of reliable observations it is difficult to assess which reanalyses are more realistic here than others. Using data from the 20th Century reanalysis and a novel century-long gridded dataset of extremes we also investigate consistency of extremes from these two datasets back to the beginning of the 20th Century. Global average time series of different extremes indices compare generally well over the past 70 years but show larger differences before around 1940. However, in areas with good observational coverage, including North America, Europe and Australia, agreement remains strong also throughout the earlier decades

  1. Experimental Analysis and Characterization on Thermal Imprint Process via In-situ Observation

    NASA Astrophysics Data System (ADS)

    Saito, Takushi; Kawaguchi, Tatsuya; Satoh, Isao

    In this study, an experimental system for in-situ observation of the thermal imprint process was constructed, and the material behavior from the initiation of transcription to product removal was precisely studied. Based on the results obtained, effect of the temperature and pressure on the transcription behavior and the shape accuracy was investigated, and the principles to obtain good replication were discussed. In addition, the exfoliation behavior of the material from substrate in the cooling stage after the transcription was observed and its characteristics were discussed.

  2. Stratified drought analysis using a stochastic ensemble of simulated and in-situ soil moisture observations

    NASA Astrophysics Data System (ADS)

    Sehgal, Vinit; Sridhar, Venkataramana; Tyagi, Aditya

    2017-02-01

    This study proposes a multi-wavelet Bayesian ensemble of two Land Surface Models (LSMs) using in-situ observations for accurate estimation of soil moisture for Contiguous United States (CONUS). In the absence of a continuous, accurate in-situ soil moisture dataset at high spatial resolution, an ensemble of Noah and Mosaic LSMs is derived by performing a Bayesian Model Averaging (BMA) of several wavelet-based multi-resolution regression models (WR) of the simulated soil moisture from the LSMs and in-situ volumetric soil moisture dataset obtained from the U.S. Climate Reference Network (USCRN) field stations. This provides a proxy to the in-situ soil moisture dataset at 1/8th degree spatial resolution called Hybrid Soil Moisture (HSM) for three soil layers (1-10 cm, 10-40 cm and 40-100 cm) for the CONUS. The derived HSM is used further to study the layer-wise response of soil moisture to drought, highlighting the necessity of the ensemble approach and soil profile perspective for drought analysis. A correlation analysis between HSM, the long-term (PDSI, PHDI, SPI-9, SPI-12 and SPI-24) and the short-term (Palmer Z index, SPI-1 and SPI-6) drought indices is carried out for the nine climate regions of the U.S. indicating a higher sensitivity of soil moisture to drought conditions for the Southern U.S. Furthermore, a layer-wise soil moisture percentile approach is proposed and applied for drought reconstruction in CONUS with a focus on the Southern U.S. for the year 2011.

  3. In Situ Optical Observation of High-Temperature Geological Processes With the Moissanite Cell

    NASA Astrophysics Data System (ADS)

    Walte, N.; Keppler, H.

    2005-12-01

    A major drawback of existing techniques in experimental earth and material sciences is the inability to observe ongoing high-temperature processes in situ during an experiment. Examples for important time-dependent processes include the textural development of rocks and oxide systems during melting and crystallization, solid-state and melt-present recrystallization and Ostwald ripening, and bubble nucleation and growth during degassing of glasses and melts. The investigation of these processes by post-mortem analysis of a quenched microstructure is time consuming and often unsatisfactory. Here, we introduce the moissanite cell that allows optical in situ observation of long-term experiments at high temperatures. Moissanite is a transparent gem-quality type of SiC that is characterized by its hardness and superior chemical and thermal resistance. Two moissanite windows with a thickness and diameter of several millimeters are placed into sockets of fired pyrophyllite and fixed onto two opposite metal plates. The sockets are wrapped with heating wire and each window is connected to a thermocouple for temperature control. The sample is placed directly between the moissanite windows and the cell is assembled similarly to a large diamond anvil cell. In situ observation of the sample is done with a microscope through observation windows and movies are recorded with an attached digital camera. Our experiments with the new cell show that temperatures above 1200°C can be maintained and observed in a sample for several days without damaging the cell nor the windows. Time-lapse movies of melting and crystallizing natural and synthetic rocks and of degassing glasses and melts will be presented to show the potential of the new technique for experimental earth and material science.

  4. SOFIA's Choice: Automating the Scheduling of Airborne Observations

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy; Norvig, Peter (Technical Monitor)

    1999-01-01

    This paper describes the problem of scheduling observations for an airborne telescope. Given a set of prioritized observations to choose from, and a wide range of complex constraints governing legitimate choices and orderings, how can we efficiently and effectively create a valid flight plan which supports high priority observations? This problem is quite different from scheduling problems which are routinely solved automatically in industry. For instance, the problem requires making choices which lead to other choices later, and contains many interacting complex constraints over both discrete and continuous variables. Furthermore, new types of constraints may be added as the fundamental problem changes. As a result of these features, this problem cannot be solved by traditional scheduling techniques. The problem resembles other problems in NASA and industry, from observation scheduling for rovers and other science instruments to vehicle routing. The remainder of the paper is organized as follows. In 2 we describe the observatory in order to provide some background. In 3 we describe the problem of scheduling a single flight. In 4 we compare flight planning and other scheduling problems and argue that traditional techniques are not sufficient to solve this problem. We also mention similar complex scheduling problems which may benefit from efforts to solve this problem. In 5 we describe an approach for solving this problem based on research into a similar problem, that of scheduling observations for a space-borne probe. In 6 we discuss extensions of the flight planning problem as well as other problems which are similar to flight planning. In 7 we conclude and discuss future work.

  5. A case study of observations of volcanic ash from the Eyjafjallajökull eruption: 2. Airborne and satellite radiative measurements

    NASA Astrophysics Data System (ADS)

    Newman, Stuart M.; Clarisse, Lieven; Hurtmans, Daniel; Marenco, Franco; Johnson, Ben; Turnbull, Kate; Havemann, Stephan; Baran, Anthony J.; O'Sullivan, Debbie; Haywood, Jim

    2012-10-01

    An extensive set of airborne and satellite observations of volcanic ash from the Eyjafjallajökull Icelandic eruption are analyzed for a case study on 17 May 2010. Data collected from particle scattering probes and backscatter lidar on the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 aircraft allow estimates of ash concentration to be derived. Using radiative transfer simulations we show that airborne and satellite infrared radiances can be accurately modeled based on the in situ measured size distribution and a mineral dust refractive index. Furthermore, airborne irradiance measurements in the 0.3-1.7 μm range are well modeled with these properties. Retrievals of ash mass column loading using Infrared Atmospheric Sounding Interferometer (IASI) observations are shown to be in accord with lidar-derived mass estimates, giving for the first time an independent verification of a hyperspectral ash variational retrieval method. The agreement of the observed and modeled solar and terrestrial irradiances suggests a reasonable degree of radiative closure implying that the physical and optical properties of volcanic ash can be relatively well constrained using data from state-of-the-science airborne platforms such as the FAAM BAe 146 aircraft. Comparisons with IASI measurements during recent Grímsvötn and Puyehue volcanic eruptions demonstrate the importance of accurately specifying the refractive index when modeling the observed spectra.

  6. Evaluation of Terms in the Water Vapor Budget Using Airborne Dial and In Situ Measurements from the Southern Great Plans 1997 Experiment

    NASA Technical Reports Server (NTRS)

    Senff, Christoph J.; Davis, Kenneth J.; Lenschow, Donald H.; Browell, Edward V.; Ismail, Syed

    1998-01-01

    The Southern Great Plains (SGP97) field experiment was conducted in Oklahoma during June and July 1997 primarily to validate soil moisture retrieval algorithms using microwave radiometer measurements from aircraft as well as in situ surface measurements. One important objective of the SGP97 experiment plan was to examine the effect of soil moisture on the evolution of the atmospheric boundary layer (ABL) and clouds over the Southern Great Plains during the warm season. To support boundary layer studies during SGP97. the NASA Langley Research Center's Lidar Atmospheric Sensing Experiment (LASE) was flown on a NASA-P3 aircraft in conjunction with the Electronically Scanned Thinned Array Radiometer (ESTAR). The LASE instrument is an airborne, downward-looking differential absorption lidar (DIAL) system capable of measuring water vapor concentration as well as aerosol backscatter with high horizontal and vertical resolution in the ABL. Here, we will demonstrate how the LASE data can be used to determine water vapor statistics and most of the water vapor budget terms in the ABL. This information can then be related to spatial variations in soil moisture and the surface energy budget. The extensive surface and aircraft in situ measurements conducted during SGP97 provide information on the ABL that cannot be retrieved from the LASE data alone and also offer an excellent opportunity to validate the remote water vapor budget measurements with LASE.

  7. Quantifying Spatial and Seasonal Variability in Atmospheric Ammonia with In Situ and Space-Based Observations

    NASA Technical Reports Server (NTRS)

    Pinder, Robert W.; Walker, John T.; Bash, Jesse O.; Cady-Pereira, Karen E.; Henze, Daven K.; Luo, Mingzhao; Osterman, Gregory B.; Shepard, Mark W.

    2011-01-01

    Ammonia plays an important role in many biogeochemical processes, yet atmospheric mixing ratios are not well known. Recently, methods have been developed for retrieving NH3 from space-based observations, but they have not been compared to in situ measurements. We have conducted a field campaign combining co-located surface measurements and satellite special observations from the Tropospheric Emission Spectrometer (TES). Our study includes 25 surface monitoring sites spanning 350 km across eastern North Carolina, a region with large seasonal and spatial variability in NH3. From the TES spectra, we retrieve a NH3 representative volume mixing ratio (RVMR), and we restrict our analysis to times when the region of the atmosphere observed by TES is representative of the surface measurement. We find that the TES NH3 RVMR qualitatively captures the seasonal and spatial variability found in eastern North Carolina. Both surface measurements and TES NH3 show a strong correspondence with the number of livestock facilities within 10 km of the observation. Furthermore, we find that TES H3 RVMR captures the month-to-month variability present in the surface observations. The high correspondence with in situ measurements and vast spatial coverage make TES NH3 RVMR a valuable tool for understanding regional and global NH3 fluxes.

  8. Validation of routine continuous airborne CO2 observations near the Bialystok Tall Tower

    NASA Astrophysics Data System (ADS)

    Chen, H.; Winderlich, J.; Gerbig, C.; Katrynski, K.; Jordan, A.; Heimann, M.

    2011-11-01

    Since 2002 in situ airborne measurements of atmospheric CO2 mixing ratios have been performed regularly aboard a rental aircraft near Bialystok (53°08' N, 23°09' E), a city in northeastern Poland. Since August 2008, the in situ CO2 measurements have been made by a modified commercially available and fully automated non-dispersive infrared (NDIR) analyzer system. The response of the analyzer has been characterized and the CO2 mixing ratio stability of the associated calibration system has been fully tested, which results in an optimal calibration strategy and allows for an accuracy of the CO2 measurements within 0.2 ppm. Besides the in situ measurements, air samples have been collected in glass flasks and analyzed in the laboratory for mixing ratios of CO2, CO, CH4, N2O, H2, SF6 and for isotopic ratios of δ13C and δ18O in CO2. To validate the in situ CO2 measurements against reliable discrete flask measurements, we developed weighting functions that mimic the temporal averaging of the flask sampling process. Comparisons between in situ and flask CO2 measurements demonstrate that these weighting functions can compensate for atmospheric variability, and provide an effective method for validating airborne in situ CO2 measurements. In addition, we show the nine-year records of flask CO2 measurements, from which the CO2 increase rates are computed for the 300 m level (1.59 ± 0.21 ppm yr-1) and for the 2500 m level (1.77 ± 0.08 ppm yr-1). The new system, automated since August 2008, has eliminated the need for manual in-flight calibrations, and thus enables an additional vertical profile, 20 km away, to be sampled at no additional cost in terms of flight hours. This sampling strategy provides an opportunity to investigate both temporal and spatial variability on a regular basis.

  9. Validation of routine continuous airborne CO2 observations near the Bialystok Tall Tower

    NASA Astrophysics Data System (ADS)

    Chen, H.; Winderlich, J.; Gerbig, C.; Katrynski, K.; Jordan, A.; Heimann, M.

    2012-04-01

    Since 2002 in situ airborne measurements of atmospheric CO2 mixing ratios have been performed regularly aboard a rental aircraft near Bialystok (53°08´ N, 23°09´ E), a city in northeastern Poland. Since August 2008, the in situ CO2 measurements have been made by a modified commercially available and fully automated non-dispersive infrared (NDIR) analyzer system. The response of the analyzer has been characterized and the CO2 mixing ratio stability of the associated calibration system has been fully tested, which results in an optimal calibration strategy and allows for an accuracy of the CO2 measurements within 0.2 ppm. Besides the in situ measurements, air samples have been collected in glass flasks and analyzed in the laboratory for CO2 and other trace gases. To validate the in situ CO2 measurements against reliable discrete flask measurements, we developed weighting functions that mimic the temporal averaging of the flask sampling process. Comparisons between in situ and flask CO2 measurements demonstrate that these weighting functions can compensate for atmospheric variability, and provide an effective method for validating airborne in situ CO2 measurements. In addition, we show the nine-year records of flask CO2 measurements. The new system, automated since August 2008, has eliminated the need for manual in-flight calibrations, and thus enables an additional vertical profile, 20 km away, to be sampled at no additional cost in terms of flight hours. This sampling strategy provides an opportunity to investigate both temporal and spatial variability on a regular basis.

  10. Pulsating aurora observed on the ground and in-situ by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Lessard, M.; Cohen, I. J.; Denton, R. E.; Engebretson, M. J.; Kletzing, C.; Wygant, J. R.; Bounds, S. R.; Smith, C. W.; MacDowall, R. J.; Kurth, W. S.

    2013-12-01

    Early observations and theory related to pulsating aurora suggested that the electrons that drive this aurora originate from the equatorial region of the magnetosphere and that a likely process that can scatter these electrons would involve chorus waves. Recent satellite observations during pulsating auroral events have provided important "firsts", including evidence of strong correlations between pulsating auroral patches and in-situ lower-band chorus (THEMIS), as well as correlations with energetic electron precipitation in the vicinity of geosynchronous orbit (GOES). These results provide important information regarding particle dynamics, leading to a question about how the chorus might be driven. We present observations of the Van Allen Probes in conjunction with a pulsating aurora event, as confirmed by observations on the ground. The in-situ data again show the presence of lower-band chorus. However, magnetic and electric field data also show that the wave bursts coincide with an apparent poloidal field-line resonance, begging the question of whether the resonance might be responsible for driving the VLF waves.

  11. Ion cyclotron instability at Io: Hybrid simulation results compared to in situ observations

    NASA Astrophysics Data System (ADS)

    Šebek, Ondřej; Trávníček, Pavel M.; Walker, Raymond J.; Hellinger, Petr

    2016-08-01

    We present analysis of global three-dimensional hybrid simulations of Io's interaction with Jovian magnetospheric plasma. We apply a single-species model with simplified neutral-plasma chemistry and downscale Io in order to resolve the ion kinetic scales. We consider charge exchange, electron impact ionization, and photoionization by using variable rates of these processes to investigate their impact. Our results are in a good qualitative agreement with the in situ magnetic field measurements for five Galileo flybys around Io. The hybrid model describes ion kinetics self-consistently. This allows us to assess the distribution of temperature anisotropies around Io and thereby determine the possible triggering mechanism for waves observed near Io. We compare simulated dynamic spectra of magnetic fluctuations with in situ observations made by Galileo. Our results are consistent with both the spatial distribution and local amplitude of magnetic fluctuations found in the observations. Cyclotron waves, triggered probably by the growth of ion cyclotron instability, are observed mainly downstream of Io and on the flanks in regions farther from Io where the ion pickup rate is relatively low. Growth of the ion cyclotron instability is governed mainly by the charge exchange rate.

  12. Developing a Scalable Remote Sampling Design for the NEON Airborne Observation Platform (AOP)

    NASA Astrophysics Data System (ADS)

    Musinsky, J.; Wasser, L. A.; Kampe, T. U.; Leisso, N.; Krause, K.; Petroy, S. B.; Cawse-Nicholson, K.; van Aardt, J. A.; Serbin, S.

    2013-12-01

    The National Ecological Observatory Network (NEON) airborne observation platform (AOP) will collect co-registered high-resolution hyperspectral imagery, discrete and waveform LiDAR, and high-resolution digital photography for more than 60 terrestrial and 23 aquatic sites spread across the continental United States, Puerto Rico, Alaska and Hawaii on an annual basis over the next 30 years. These data, to be made freely available to the public, will facilitate the scaling of field-based biological, physical and chemical measurements to regional and continental scales, enabling a better understanding of the relationships between climate variability and change, land use change and invasive species, and their ecological consequences in areas not directly sampled by the NEON facilities. However, successful up-scaling of in situ measurements requires a flight sampling design that captures environmental heterogeneity and diversity (i.e., ecological and topographic gradients), is sensitive to temporal system variation (e.g., phenology), and can respond to major disturbance events. Alignment of airborne campaigns - composed of two payloads for nominal science acquisitions and one payload for PI-driven rapid-response campaigns -- with other ground, airborne (e.g., AVIRIS) and satellite (e.g., Landsat, MODIS) collections will further facilitate scaling between sensors and data sources of varying spatial and spectral resolution and extent. This presentation will discuss the approach, challenges and future goals associated with the development of NEON AOP's sampling design, using examples from the 2013 nominal flight campaigns in the Central Plains (NEON Domain 10) and the Pacific Southwest (Domain 17), and the rapid response flight campaign of the High Park Fire site outside of Fort Collins, CO. Determination of the specific flight coverage areas for each campaign involved analysis of the landscape scale ecological, geophysical and bioclimatic attributes and trends most closely

  13. In situ Microscopic Observation of Sodium Deposition/Dissolution on Sodium Electrode

    PubMed Central

    Yui, Yuhki; Hayashi, Masahiko; Nakamura, Jiro

    2016-01-01

    Electrochemical sodium deposition/dissolution behaviors in propylene carbonate-based electrolyte solution were observed by means of in situ light microscopy. First, granular sodium was deposited at pits in a sodium electrode in the cathodic process. Then, the sodium particles grew linearly from the electrode surface, becoming needle-like in shape. In the subsequent anodic process, the sodium dissolved near the base of the needles on the sodium electrode and the so-called “dead sodium” broke away from the electrode. The mechanisms of electrochemical sodium deposition and dissolution on a copper electrode were similar to those on the sodium electrode. PMID:26925554

  14. In situ SEM observation of column-like and foam-like CNT array nanoindentation.

    PubMed

    Maschmann, Matthew R; Zhang, Qiuhong; Wheeler, Robert; Du, Feng; Dai, Liming; Baur, Jeffery

    2011-03-01

    Quantitative nanoindentation of nominally 7.5 and 600 μm tall vertically aligned carbon nanotube (VACNT) arrays is observed in situ within an SEM chamber. The 7.5 μm array consists of highly aligned and weakly interacting CNTs and deflects similarly to classically defined cylindrical columns, with deformation geometry and critical buckling force well estimated using the Euler-Bernoulli theory. The 600 μm array has a highly entangled foam-like morphology and exhibits sequential buckle formation upon loading, with a buckle first forming near the array bottom at approximately 2% strain, followed by accumulating coordinated buckling at the top surface at strains exceeding 5%.

  15. Airborne observations of cloud properties on HALO during NARVAL

    NASA Astrophysics Data System (ADS)

    Konow, Heike; Hansen, Akio; Ament, Felix

    2016-04-01

    The representation of cloud and precipitation processes is one of the largest sources of uncertainty in climate and weather predictions. To validate model predictions of convective processes over the Atlantic ocean, usually satellite data are used. However, satellite products provide just a coarse view with poor temporal resolution of convective maritime clouds. Aircraft-based observations offer a more detailed insight due to lower altitude and high sampling rates. The research aircraft HALO (High Altitude Long Range Research Aircraft) is operated by the German Aerospace Center (DLR). With a ceiling of 15 km, and a range of 10,000 km and more than 10 hours it is able to reach remote regions and operate from higher altitudes than most other research aircraft. Thus, it provides the unique opportunity to exploit regions of the atmosphere that cannot be easily accessed otherwise. Measurements conducted on HALO provide more detailed insights than achievable from satellite data. Therefore, this measurement platform bridges the gap between previous airborne measurements and satellites. The payload used for this study consists of, amongst others, a suite of passive microwave radiometers, a cloud radar, and a water vapor DIAL. To investigate cloud and precipitation properties of convective maritime clouds, the NARVAL (Next-generation Aircraft Remote-Sensing for Validation Studies) campaign was conducted in winter 2013/2014 out of Barbados and Keflavik (Iceland). This campaign was one of the first that took place on the HALO aircraft. During the experiment's two parts 15 research flights were conducted (8 flights during NARVAL-South out of Barbados to investigate trade-wind cumuli and 7 flights out of Keflavik with focus on mid-latitude cyclonic systems). Flight durations were between five and nine hours, amounting to roughly 118 flight hours overall. 121 dropsondes were deployed. In fall 2016 two additional aircraft campaigns with the same payload will take place: The

  16. Design and instrumentation of an airborne far infrared radiometer for in-situ measurements of ice clouds

    NASA Astrophysics Data System (ADS)

    Proulx, Christian; Ngo Phong, Linh; Lamontagne, Frédéric; Wang, Min; Fisette, Bruno; Martin, Louis; Châteauneuf, François

    2016-09-01

    We report on the design and instrumentation of an aircraft-certified far infrared radiometer (FIRR) and the resulting instrument characteristics. FIRR was designed to perform unattended airborne measurements of ice clouds in the arctic in support of a microsatellite payload study. It provides radiometrically calibrated data in nine spectral channels in the range of 8-50 μm with the use of a rotating wheel of bandpass filters and reference blackbodies. Measurements in this spectral range are enabled with the use of a far infrared detector based on microbolometers of 104-μm pitch. The microbolometers have a new design because of the large structure and are coated with gold black to maintain uniform responsivity over the working spectral range. The vacuum sealed detector package is placed at the focal plane of a reflective telescope based on a Schwarschild configuration with two on-axis spherical mirrors. The telescope field-of-view is of 6° and illuminates an area of 2.1-mm diameter at the focal plane. In operation, FIRR was used as a nonimaging radiometer and exhibited a noise equivalent radiance in the range of 10-20 mW/m2-sr. The dynamic range and the detector vacuum integrity of FIRR were found to be suited for the conditions of the airborne experiments.

  17. High-resolution NO2 observations from the Airborne Compact Atmospheric Mapper: Retrieval and validation

    NASA Astrophysics Data System (ADS)

    Lamsal, L. N.; Janz, S. J.; Krotkov, N. A.; Pickering, K. E.; Spurr, R. J. D.; Kowalewski, M. G.; Loughner, C. P.; Crawford, J. H.; Swartz, W. H.; Herman, J. R.

    2017-02-01

    Nitrogen dioxide (NO2) is a short-lived atmospheric pollutant that serves as an air quality indicator and is itself a health concern. The Airborne Compact Atmospheric Mapper (ACAM) was flown on board the NASA UC-12 aircraft during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality Maryland field campaign in July 2011. The instrument collected hyperspectral remote sensing measurements in the 304-910 nm range, allowing daytime observations of several tropospheric pollutants, including nitrogen dioxide (NO2), at an unprecedented spatial resolution of 1.5 × 1.1 km2. Retrievals of slant column abundance are based on the differential optical absorption spectroscopy method. For the air mass factor computations needed to convert these retrievals to vertical column abundance, we include high-resolution information for the surface reflectivity by using bidirectional reflectance distribution function data from the Moderate Resolution Imaging Spectroradiometer. We use high-resolution simulated vertical distributions of NO2 from the Community Multiscale Air Quality and Global Modeling Initiative models to account for the temporal variation in atmospheric NO2 to retrieve middle and lower tropospheric NO2 columns (NO2 below the aircraft). We compare NO2 derived from ACAM measurements with in situ observations from NASA's P-3B research aircraft, total column observations from the ground-based Pandora spectrometers, and tropospheric column observations from the space-based Ozone Monitoring Instrument. The high-resolution ACAM measurements not only give new insights into our understanding of atmospheric composition and chemistry through observation of subsampling variability in typical satellite and model resolutions, but they also provide opportunities for testing algorithm improvements for forthcoming geostationary air quality missions.

  18. A Reevaluation of Airborne HO(x) Observations from NASA Field Campaigns

    NASA Technical Reports Server (NTRS)

    Olson, Jennifer; Crawford, James H.; Chen, Gao; Brune, William H.; Faloona, Ian C.; Tan, David; Harder, Hartwig; Martinez, Monica

    2006-01-01

    In-situ observations of tropospheric HO(x) (OH and HO2) obtained during four NASA airborne campaigns (SUCCESS, SONEX, PEM-Tropics B and TRACE-P) are reevaluated using the NASA Langley time-dependent photochemical box model. Special attention is given to previously diagnosed discrepancies between observed and predicted HO2 which increase with higher NO(x) levels and at high solar zenith angles. This analysis shows that much of the model discrepancy at high NO(x) during SUCCESS can be attributed to modeling observations at time-scales too long to capture the nonlinearity of HO(x) chemistry under highly variable conditions for NO(x). Discrepancies at high NO(x) during SONEX can be moderated to a large extent by complete use of all available precursor observations. Differences in kinetic rate coefficients and photolysis frequencies available for previous studies versus current recommendations also explain some of the disparity. Each of these causes is shown to exert greater influence with increasing NO(x) due to both the chemical nonlinearity between HO(x) and NO(x) and the increased sensitivity of HO(x) to changes in sources at high NO(x). In contrast, discrepancies at high solar zenith angles will persist until an adequate nighttime source of HO(x) can be identified. It is important to note that this analysis falls short of fully eliminating the issue of discrepancies between observed and predicted HO(x) for high NO(x) environments. These discrepancies are not resolved with the above causes in other data sets from ground-based field studies. Nevertheless, these results highlight important considerations in the application of box models to observationally based predictions of HO(x) radicals.

  19. In Situ Observation for Abnormal Grain Coarsening in Vacuum-Carburizing Process

    NASA Astrophysics Data System (ADS)

    Yogo, Yasuhiro; Tanaka, Kouji

    2014-06-01

    An in situ observation method was developed to investigate abnormal grain coarsening which occurs around the surface of steel during the vacuum-carburizing process. In this method, diffusion of carbon atoms in the vacuum carburizing was simulated by a cementite and steel diffusion couple. Abnormal grain coarsening, which appeared around the cementite and steel interface, was observed by a confocal scanning laser microscope. With this method, it was observed that when holding time was 60 seconds, the temperature at which the abnormal grain coarsening appeared in a specimen was higher when carburized than the temperature when not carburized. On the contrary, when holding time was 120 seconds, the temperature at which the abnormal grain coarsening appeared in a specimen was 10 K to 20 K lower than that in a non-carburized specimen. The validity of the observed results was confirmed by the calculated NbC fraction using Nb solubility and measured carbon content.

  20. In situ observations of suprathermal ion acceleration in the near-Earth jet braking region

    NASA Astrophysics Data System (ADS)

    Retinò, Alessandro; Khotyaintsev, Yuri; Vaivads, Andris; Le Contel, Olivier; Fu, Huishan; Zieger, Bertalan; Elena, Kronberg

    2014-05-01

    Plasma jet fronts and braking regions are sites of substantial particle acceleration in planetary magnetospheres and are considered to play a major role in other distant environments such as the solar corona and astrophysical jets. Jet fronts are the boundaries separating ambient from jetting plasma (e.g. due to reconnection) while jet braking regions is where jets are eventually stopped/diverted. A number of recent in situ observations in the Earth's magnetotail have allowed studying in detail electron acceleration mechanisms at jet fronts/braking region therein. Yet, observations of suprathermal ion acceleration are scarce. Here we show Cluster spacecraft observations of suprathermal ions up to ~ 1 MeV (about 10 times the thermal energy) in the near-Earth jet braking region. Observations indicate that ions are trapped between large-scale oppositely-directed jets and accelerated therein by strong electric fields.

  1. In situ observation of elementary growth processes of protein crystals by advanced optical microscopy.

    PubMed

    Sazaki, Gen; Van Driessche, Alexander E S; Dai, Guoliang; Okada, Masashi; Matsui, Takuro; Otálora, Fermin; Tsukamoto, Katsuo; Nakajima, Kazuo

    2012-07-01

    To start systematically investigating the quality improvement of protein crystals, the elementary growth processes of protein crystals must be first clarified comprehensively. Atomic force microscopy (AFM) has made a tremendous contribution toward elucidating the elementary growth processes of protein crystals and has confirmed that protein crystals grow layer by layer utilizing kinks on steps, as in the case of inorganic and low-molecular-weight compound crystals. However, the scanning of the AFM cantilever greatly disturbs the concentration distribution and solution flow in the vicinity of growing protein crystals. AFM also cannot visualize the dynamic behavior of mobile solute and impurity molecules on protein crystal surfaces. To compensate for these disadvantages of AFM, in situ observation by two types of advanced optical microscopy has been recently performed. To observe the elementary steps of protein crystals noninvasively, laser confocal microscopy combined with differential interference contrast microscopy (LCM-DIM) was developed. To visualize individual mobile protein molecules, total internal reflection fluorescent (TIRF) microscopy, which is widely used in the field of biological physics, was applied to the visualization of protein crystal surfaces. In this review, recent progress in the noninvasive in situ observation of elementary steps and individual mobile protein molecules on protein crystal surfaces is outlined.

  2. A century of ocean warming on Florida Keys coral reefs: historic in situ observations

    USGS Publications Warehouse

    Kuffner, Ilsa B.; Lidz, Barbara H.; Hudson, J. Harold; Anderson, Jeffery S.

    2015-01-01

    There is strong evidence that global climate change over the last several decades has caused shifts in species distributions, species extinctions, and alterations in the functioning of ecosystems. However, because of high variability on short (i.e., diurnal, seasonal, and annual) timescales as well as the recency of a comprehensive instrumental record, it is difficult to detect or provide evidence for long-term, site-specific trends in ocean temperature. Here we analyze five in situ datasets from Florida Keys coral reef habitats, including historic measurements taken by lighthouse keepers, to provide three independent lines of evidence supporting approximately 0.8 °C of warming in sea surface temperature (SST) over the last century. Results indicate that the warming observed in the records between 1878 and 2012 can be fully accounted for by the warming observed in recent decades (from 1975 to 2007), documented using in situ thermographs on a mid-shore patch reef. The magnitude of warming revealed here is similar to that found in other SST datasets from the region and to that observed in global mean surface temperature. The geologic context and significance of recent ocean warming to coral growth and population dynamics are discussed, as is the future prognosis for the Florida reef tract.

  3. Validation of EGSIEM gravity field products with globally distributed in situ ocean bottom pressure observations

    NASA Astrophysics Data System (ADS)

    Poropat, Lea; Bergmann-Wolf, Inga; Flechtner, Frank; Dobslaw, Henryk

    2016-04-01

    Time variable global gravity field models that are processed by different research institutions all across Europe are currently compared and subsequently combined within the "European Gravity Field Service for Improved Emergency Management (EGSIEM)" project funded by the European Union. To objectively assess differences between the results from different groups, and also to evaluate the impact of changes in the data processing at an individual institution in preparation of a new data release, a validation of the final GRACE gravity fields against independent observations is required. 
For such a validation, we apply data from a set of globally distributed ocean bottom pressure sensors. The in situ observations have been thoroughly revised for outliers, instrumental drift and jumps, and were additionally reduced for tides. GRACE monthly mean solutions are then validated with the monthly resampled in situ observations. The validation typically concentrates on seasonal to interannual signals, but in case of GRACE-based series with daily sampling available from, e.g., Kalman Smoother Solutions, also sub-monthly signal variability can be assessed.

  4. In Situ fracture observation and fracture toughness analysis of pearlitic graphite cast irons with different nodularity

    NASA Astrophysics Data System (ADS)

    Han, Seung Youb; Sohn, Seok Su; Shin, Sang Yong; Lee, Sunghak; Suh, Yong Chan

    2013-07-01

    Effects of microstructural modification and microfracture mechanisms on fracture toughness of pearlitic graphite cast irons with different nodularity were investigated by in situ observation of microfracture process. Six pearlitic graphite cast irons were fabricated by adding a small amount of Mg as a nodularizing element for graphite, and their microstructures including pearlite, ferrite, graphite, and eutectic carbide were analyzed. Most of ferrites were observed in a layer shape around graphites because of carbon-depleted zones formed near graphites. As the nodularity and nodule count increased, fracture toughness linearly increased in the cast irons except the iron containing many fine graphites. According to in situ observation of microfracture process, cracks initiated at nodular graphites and carbides even at a small load, and then propagated readily through the adjacent graphites or carbides, thereby resulting in the lowest fracture toughness. The cast iron having widely spaced graphites and ferrite layers thickly formed around graphites showed the highest fracture toughness because of the blocking of crack propagation by ductile ferrite layers and the crack blunting and deflection by graphites, which was also confirmed by the R-curve analysis.

  5. High-temperature in situ crystallographic observation of reversible gas sorption in impermeable organic cages.

    PubMed

    Baek, Seung Bin; Moon, Dohyun; Graf, Robert; Cho, Woo Jong; Park, Sung Woo; Yoon, Tae-Ung; Cho, Seung Joo; Hwang, In-Chul; Bae, Youn-Sang; Spiess, Hans W; Lee, Hee Cheon; Kim, Kwang S

    2015-11-17

    Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2 sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl)benzene (H3BTB) and N,N-dimethylformamide (DMF) and by π-π stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready use.

  6. High-temperature in situ crystallographic observation of reversible gas sorption in impermeable organic cages

    PubMed Central

    Baek, Seung Bin; Moon, Dohyun; Graf, Robert; Cho, Woo Jong; Park, Sung Woo; Yoon, Tae-Ung; Cho, Seung Joo; Hwang, In-Chul; Bae, Youn-Sang; Spiess, Hans W.; Lee, Hee Cheon; Kim, Kwang S.

    2015-01-01

    Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2 sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl)benzene (H3BTB) and N,N-dimethylformamide (DMF) and by π–π stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready use. PMID:26578758

  7. Sensor Web Standards for Interoperability between in-situ Earth Observation Networks

    NASA Astrophysics Data System (ADS)

    Rieke, Matthes; Casas, Raquel; Garcia, Oscar; Jirka, Simon; Menard, Lionel; Ranchin, Thierry; Stasch, Christoph; Wald, Lucien

    2016-04-01

    Existing earth observation networks deliver a multitude of in-situ data capturing the state of the earth. The data sets delivered by these networks are of high value for scientists and other stakeholders from different domains and backgrounds. However, the access and integration of the data sets made available by these earth observation networks are often complex as different data delivery methods and formats are used. To strengthen and broaden the use of the available data sets, it is important to offer efficient methods for accessing the data from different types of applications (e.g. for data analysis or data visualisation). The Sensor Web Enablement (SWE) standards of the Open Geospatial Consortium (OGC) are adopted by more and more stakeholders and may serve as a good baseline for increasing the interoperability of data flows. This harmonisation of standards is also one of the core objectives of the ENEON (European Network of Earth Observation Networks) initiative promoted by the European Horizon 2020 project ConnectinGEO (Coordinating an Observation Network of Networks EnCompassing saTellite and IN-situ to fill the Gaps in European Observations). In this contribution, we illustrate how domain-specific profiles of the OGC SWE standards may help to increase interoperability within specific domains. This includes for example the specification of SWE profiles for hydrology (e.g. resulting from the European GEOWOW project) or the e-Reporting SWE profiles for ambient air quality in Europe. Another example are SWE profiles for oceanology which are currently developed by several projects such as BRIDGES, Eurofleets 2, FixO3, IOOS, Jerico-Next, NeXOS, ODIP II, and SeaDataNet (e.g. using RelaxNG and Schematron for defining a structure of SWE encoded messages to be applied in tools, vessels and fixed stations). Finally, a Sensor Web-based scenario from the ConnectinGEO project covering energy and solar radiation will be introduced that connects data providers and users

  8. In-situ TEM observation of nano-void formation in UO2 under irradiation

    NASA Astrophysics Data System (ADS)

    Sabathier, C.; Martin, G.; Michel, A.; Carlot, G.; Maillard, S.; Bachelet, C.; Fortuna, F.; Kaitasov, O.; Oliviero, E.; Garcia, P.

    2014-05-01

    Transmission electron microscopy (TEM) observations of UO2 polycrystals irradiated in situ with 4 MeV Au ions were performed at room temperature (RT) to better understand the mechanisms of cavity and ultimately fission products nucleation in UO2. Experiments were carried out at the JANNuS Orsay facility that enables in situ ion irradiations inside the microscope to be carried out. The majority of 4 MeV gold ions were transmitted through the thin foil, and the induced radiation defects were investigated by TEM. Observations showed that nano-void formation occurs at ambient temperature in UO2 thin foils irradiated with energetic heavy ions under an essentially nuclear energy loss regime. The diameter and density of nano-objects were measured as a function of the gold irradiation dose at RT. A previous paper has also revealed a similar nano-object population after a Xe implantation performed at 390 keV at 870 K. The nano-object density was modelled using simple concepts derived from Classical Molecular Dynamics simulations. The results are in good agreement, which suggests a mechanism of heterogeneous nucleation induced by energetic cascade overlaps. This indicates that nano-void formation mechanism is controlled by radiation damage. Such nanovoids are likely to act as sinks for mobile fission products during reactor operation.

  9. In situ observation of quasimelting of diamond and reversible graphite-diamond phase transformations.

    PubMed

    Huang, J Y

    2007-08-01

    Because of technique difficulties in achieving the extreme high-pressure and high-temperature (HPHT) simultaneously, direct observation of the structures of carbon at extreme HPHT conditions has not been possible. Banhart and Ajayan discovered remarkably that carbon onions can act as nanoscopic pressure cells to generate high pressures. By heating carbon onions to approximately 700 degrees C and under electron beam irradiation, the graphite-to-diamond transformation was observed in situ by transmission electron microscopy (TEM). However, the highest achievable temperature in a TEM heating holder is less than 1000 degrees C. Here we report that, by using carbon nanotubes as heaters and carbon onions as high-pressure cells, temperatures higher than 2000 degrees C and pressures higher than 40 GPa were achieved simultaneously in carbon onions. At such HPHT conditions and facilitated by electron beam irradiation, the diamond formed in the carbon onion cores frequently changed its shape, size, orientation, and internal structure and moved like a fluid, implying that it was in a quasimelting state. The fluctuation between the solid phase of diamond and the fluid/amorphous phase of diamond-like carbon, and the changes of the shape, size, and orientation of the solid diamond, were attributed to the dynamic crystallization of diamond crystal from the quasimolten state and the dynamic graphite-diamond phase transformations. Our discovery offers unprecedented opportunities to studying the nanostructures of carbon at extreme conditions in situ and at an atomic scale.

  10. In-situ observations of Eyjafjallajökull ash particles by hot-air balloon

    NASA Astrophysics Data System (ADS)

    Petäjä, T.; Laakso, L.; Grönholm, T.; Launiainen, S.; Evele-Peltoniemi, I.; Virkkula, A.; Leskinen, A.; Backman, J.; Manninen, H. E.; Sipilä, M.; Haapanala, S.; Hämeri, K.; Vanhala, E.; Tuomi, T.; Paatero, J.; Aurela, M.; Hakola, H.; Makkonen, U.; Hellén, H.; Hillamo, R.; Vira, J.; Prank, M.; Sofiev, M.; Siitari-Kauppi, M.; Laaksonen, A.; lehtinen, K. E. J.; Kulmala, M.; Viisanen, Y.; Kerminen, V.-M.

    2012-03-01

    The volcanic ash cloud from Eyjafjallajökull volcanic eruption seriously distracted aviation in Europe. Due to the flight ban, there were only few in-situ measurements of the properties and dispersion of the ash cloud. In this study we show in-situ observations onboard a hot air balloon conducted in Central Finland together with regional dispersion modelling with SILAM-model during the eruption. The modeled and measured mass concentrations were in a qualitative agreement but the exact elevation of the layer was slightly distorted. Some of this discrepancy can be attributed to the uncertainty in the initial emission height and strength. The observed maximum mass concentration varied between 12 and 18 μg m -3 assuming a density of 2 g m -3, whereas the gravimetric analysis of the integrated column showed a maximum of 45 μg m -3 during the first two descents through the ash plume. Ion chromatography data indicated that a large fraction of the mass was insoluble to water, which is in qualitative agreement with single particle X-ray analysis. A majority of the super-micron particles contained Si, Al, Fe, K, Na, Ca, Ti, S, Zn and Cr, which are indicative for basalt-type rock material. The number concentration profiles indicated that there was secondary production of particles possibly from volcano-emitted sulfur dioxide oxidized to sulfuric acid during the transport.

  11. Earth's ion upflow associated with polar cap patches: Global and in situ observations

    NASA Astrophysics Data System (ADS)

    Zhang, Qing-He; Zong, Qiu-Gang; Lockwood, Michael; Heelis, Roderick A.; Hairston, Marc; Liang, Jun; McCrea, Ian; Zhang, Bei-Chen; Moen, Jøran; Zhang, Shun-Rong; Zhang, Yong-Liang; Ruohoniemi, J. Michael; Lester, Mark; Thomas, Evan G.; Liu, Rui-Yuan; Dunlop, Malcolm W.; Liu, Yong C.-M.; Ma, Yu-Zhang

    2016-03-01

    We report simultaneous global monitoring of a patch of ionization and in situ observation of ion upflow at the center of the polar cap region during a geomagnetic storm. Our observations indicate strong fluxes of upwelling O+ ions originating from frictional heating produced by rapid antisunward flow of the plasma patch. The statistical results from the crossings of the central polar cap region by Defense Meteorological Satellite Program F16-F18 from 2010 to 2013 confirm that the field-aligned flow can turn upward when rapid antisunward flows appear, with consequent significant frictional heating of the ions, which overcomes the gravity effect. We suggest that such rapidly moving patches can provide an important source of upwelling ions in a region where downward flows are usually expected. These observations give new insight into the processes of ionosphere-magnetosphere coupling.

  12. In-Situ Observation of Horizontal Centrifugal Casting using a High-Speed Camera

    NASA Astrophysics Data System (ADS)

    Esaka, Hisao; Kawai, Kohsuke; Kaneko, Hiroshi; Shinozuka, Kei

    2012-07-01

    In order to understand the solidification process of horizontal centrifugal casting, experimental equipment for in-situ observation using transparent organic substance has been constructed. Succinonitrile-1 mass% water alloy was filled in the round glass cell and the glass cell was completely sealed. To observe the movement of equiaxed grains more clearly and to understand the effect of movement of free surface, a high-speed camera has been installed on the equipment. The most advantageous point of this equipment is that the camera rotates with mold, so that one can observe the same location of the glass cell. Because the recording rate could be increased up to 250 frames per second, the quality of movie was dramatically modified and this made easier and more precise to pursue the certain equiaxed grain. The amplitude of oscillation of equiaxed grain ( = At) decreased as the solidification proceeded.

  13. Airborne lidar and radiometric observations of PBL- and low clouds

    NASA Technical Reports Server (NTRS)

    Flamant, P. H.; Valentin, R.; Pelon, J.

    1992-01-01

    Boundary layer- and low altitude clouds over open ocean and continent areas have been studied during several field campaigns since mid-1990 using the French airborne backscatter lidar LEANDRE in conjunction with on-board IR and visible radiometers. LEANDRE is an automatic system, and a modification of the instrumental parameters, when airborne, is computer controlled through an operator keyboard. The vertical range squared lidar signals and instrument status are displayed in real time on two dedicated monitors. The lidar is used either down- or up-looking while the aircraft is flying above or below clouds. A switching of the viewing configuration takes about a minute. The lidar measurements provide a high resolution description of cloud morphology and holes in cloud layers. The flights were conducted during various meteorological conditions on single or multilayer stratocumulus and cumulus decks. Analysis on a single shot basis of cloud top (or bottom) altitude and a plot of the corresponding histogram allows one to determine a probability density function (PDF). The preliminary results show the PDFs for cloud top are not Gaussian and symmetric about the mean value. The skewness varies with atmospheric conditions. An example of results recorded over the Atlantic ocean near Biarritz is displayed, showing: (1) the range squared lidar signals as a function of time (here 100 s corresponds to about 8 km, 60 shots are averaged on horizontal); the Planetary Boundary Layer (PBL) - up to 600 m - is observed at the beginning of the leg as well as on surface returns, giving an indication of the porosity; (2) the cloud top altitude variation between 2.4 to 2.8 km during the 150 to 320 s section; and (3) the corresponding PDF. Similar results are obtained on stratocumulus over land. Single shot measurements can be used also to determine an optical porosity at a small scale as well as a fractional cloudiness at a larger scale. A comparison of cloud top altitude retrieved from

  14. Ionospheric Cubeswarm Concept Study: using low-resource instrumentation for truly multipoint in situ ionospheric observations

    NASA Astrophysics Data System (ADS)

    Hampton, D.; Lynch, K. A.; Earle, G. D.; Mannucci, A. J.; Clayton, R.; Fisher, L. E.; Fernandes, P. A.; Roberts, M.; Zettergren, M. D.

    2015-12-01

    Magnetosphere-ionosphere coupling currents close in the nightside lower ionosphere. These spatially inhomogeneous and time varying volume currents are difficult to capture with in situ observations. Our understanding of M-I coupling systems is limited by our understanding of the actual structure of ionospheric current closure. A path forward includes assimilation of a variety of data sets into increasingly capable ionospheric models. While each data set provides only a piece of the picture, the assimilation process allows optimal use of each piece.An important development for the necessary in situ observations involves making them truly multi-point, and therefore, low-resource. For thermal particle observations, the high densities of the lower ionosphere allow the use of low-gain (current-sensing rather than particle-counting) particle sensors. One observational goal is the definition of the actual structure of ionospheric closure currents. This can be approached with a number of different measurement techniques, in tandem with an ionospheric model, since the closure currents need to follow the rules of electrodynamics and current continuity. Low resource thermal plasma sensors such as retarding potential analyzers and drift meters can provide valuable measurements of plasma parameters, including density and plasma flow, without the need for high voltages or deployable boom systems. These low-resource measurements, which can be reproduced on arrays of in situ observation platforms, used in tandem with proper plasma physics interpretation of their signatures in the disturbed observing environment, and as part of an assimilated data set into an ionospheric model, can allow us to progress in our understanding of ionospheric structuring and its effects on auroral coupling. Now, with increasingly capable multipoint arrays of spacecraft, and quantitative 2D-with-time context from cameras and imagery, we are moving toward truly multipoint studies of the system

  15. Airborne observations of the microphysical structure of two contrasting cirrus clouds

    NASA Astrophysics Data System (ADS)

    O'Shea, S. J.; Choularton, T. W.; Lloyd, G.; Crosier, J.; Bower, K. N.; Gallagher, M.; Abel, S. J.; Cotton, R. J.; Brown, P. R. A.; Fugal, J. P.; Schlenczek, O.; Borrmann, S.; Pickering, J. C.

    2016-11-01

    We present detailed airborne in situ measurements of cloud microphysics in two midlatitude cirrus clouds, collected as part of the Cirrus Coupled Cloud-Radiation Experiment. A new habit recognition algorithm for sorting cloud particle images using a neural network is introduced. Both flights observed clouds that were related to frontal systems, but one was actively developing while the other dissipated as it was sampled. The two clouds showed distinct differences in particle number, habit, and size. However, a number of common features were observed in the 2-D stereo data set, including a distinct bimodal size distribution within the higher-temperature regions of the clouds. This may result from a combination of local heterogeneous nucleation and large particles sedimenting from aloft. Both clouds had small ice crystals (<100 µm) present at all levels However, this small ice mode is not present in observations from a holographic probe. This raises the possibility that the small ice observed by optical array probes may at least be in part an instrument artifact due to the counting of out-of-focus large particles as small ice. The concentrations of ice crystals were a factor 10 higher in the actively growing cloud with the stronger updrafts, with a mean concentration of 261 L-1 compared to 29 L-1 in the decaying case. Particles larger than 700 µm were largely absent from the decaying cirrus case. A comparison with ice-nucleating particle parameterizations suggests that for the developing case the ice concentrations at the lowest temperatures are best explained by homogenous nucleation.

  16. In-situ observation of impurity diffusion boundary layer in silicon Czochralski growth

    NASA Astrophysics Data System (ADS)

    Kakimoto, Koichi; Eguchi, Minoru; Watanabe, Hisao; Hibiya, Taketoshi

    1990-01-01

    In-situ observation of the impurity diffusion boundary layer during single crystal growth of indium-doped silicon was carried out by X-ray radiography. The difference in the transmitted X-ray image compared with molten silicon just beneath the crystal-melt interface was attributed to the concentration of indium impurities having a larger absorption coefficient. The intensity profile of the transmitted X-ray can be reproduced by a transmittance calculation that considers the meniscus shape and impurity distribution. The impurity distribution profile near the crystal-melt interface was estimated using the Burton-Prim-Slichter (BPS) equation. The observed impurity diffusion boundary layer thickness was about 0.5 mm. It was found that the boundary layer thickness was not constant in the radial direction, which cannot be explained by the BPS theory, since it is based on a one-dimensional calculation.

  17. Groundwater quality and depletion in the Indo-Gangetic Basin mapped from in situ observations

    NASA Astrophysics Data System (ADS)

    MacDonald, A. M.; Bonsor, H. C.; Ahmed, K. M.; Burgess, W. G.; Basharat, M.; Calow, R. C.; Dixit, A.; Foster, S. S. D.; Gopal, K.; Lapworth, D. J.; Lark, R. M.; Moench, M.; Mukherjee, A.; Rao, M. S.; Shamsudduha, M.; Smith, L.; Taylor, R. G.; Tucker, J.; van Steenbergen, F.; Yadav, S. K.

    2016-10-01

    Groundwater abstraction from the transboundary Indo-Gangetic Basin comprises 25% of global groundwater withdrawals, sustaining agricultural productivity in Pakistan, India, Nepal and Bangladesh. Recent interpretations of satellite gravity data indicate that current abstraction is unsustainable, yet these large-scale interpretations lack the spatio-temporal resolution required to govern groundwater effectively. Here we report new evidence from high-resolution in situ records of groundwater levels, abstraction and groundwater quality, which reveal that sustainable groundwater supplies are constrained more by extensive contamination than depletion. We estimate the volume of groundwater to 200 m depth to be >20 times the combined annual flow of the Indus, Brahmaputra and Ganges, and show the water table has been stable or rising across 70% of the aquifer between 2000 and 2012. Groundwater levels are falling in the remaining 30%, amounting to a net annual depletion of 8.0 +/- 3.0 km3. Within 60% of the aquifer, access to potable groundwater is restricted by excessive salinity or arsenic. Recent groundwater depletion in northern India and Pakistan has occurred within a longer history of groundwater accumulation from extensive canal leakage. This basin-wide synthesis of in situ groundwater observations provides the spatial detail essential for policy development, and the historical context to help evaluate recent satellite gravity data.

  18. In situ observations of waves in Venus’s polar lower thermosphere with Venus Express aerobraking

    NASA Astrophysics Data System (ADS)

    Müller-Wodarg, Ingo C. F.; Bruinsma, Sean; Marty, Jean-Charles; Svedhem, Håkan

    2016-08-01

    Waves are ubiquitous phenomena found in oceans and atmospheres alike. From the earliest formal studies of waves in the Earth’s atmosphere to more recent studies on other planets, waves have been shown to play a key role in shaping atmospheric bulk structure, dynamics and variability. Yet, waves are difficult to characterize as they ideally require in situ measurements of atmospheric properties that are difficult to obtain away from Earth. Thus, we have incomplete knowledge of atmospheric waves on planets other than our own, and we are thereby limited in our ability to understand and predict planetary atmospheres. Here we report the first ever in situ observations of atmospheric waves in Venus’s thermosphere (130-140 km) at high latitudes (71.5°-79.0°). These measurements were made by the Venus Express Atmospheric Drag Experiment (VExADE) during aerobraking from 24 June to 11 July 2014. As the spacecraft flew through Venus’s atmosphere, deceleration by atmospheric drag was sufficient to obtain from accelerometer readings a total of 18 vertical density profiles. We infer an average temperature of T = 114 +/- 23 K and find horizontal wave-like density perturbations and mean temperatures being modulated at a quasi-5-day period.

  19. Reconciling Spectroscopic Electron Temperature Measurements in the Solar Corona with In Situ Charge State Observations.

    PubMed

    Esser; Edgar

    2000-03-20

    It has been a puzzle for quite some time that spectroscopic measurements in the inner corona indicate electron temperatures far too low to produce the ion fractions observed in situ in the solar wind. In the present Letter, we show that in order to reconcile the two sets of measurements, a number of conditions have to exist in the inner corona: (1) The electron distribution function has to be Maxwellian or close to Maxwellian at the coronal base, (2) the non-Maxwellian character of the distribution has to develop rapidly as a function of height and has to reach close to interplanetary properties inside of a few solar radii, and (3) ions of different elements have to flow with significantly different speeds to separate their "freezing-in" distances sufficiently so that they can encounter different distribution functions. We choose two examples to demonstrate that these conditions are general requirements if both coronal electron temperatures and in situ ion fractions are correct. However, these two examples also show that the details of the required distribution functions are very sensitive to the exact electron temperature, density, and ion flow speed profiles in the region of the corona where the ions predominantly form.

  20. Are Global In-Situ Ocean Observations Fit-for-purpose? Applying the Framework for Ocean Observing in the Atlantic.

    NASA Astrophysics Data System (ADS)

    Visbeck, M.; Fischer, A. S.; Le Traon, P. Y.; Mowlem, M. C.; Speich, S.; Larkin, K.

    2015-12-01

    There are an increasing number of global, regional and local processes that are in need of integrated ocean information. In the sciences ocean information is needed to support physical ocean and climate studies for example within the World Climate Research Programme and its CLIVAR project, biogeochemical issues as articulated by the GCP, IMBER and SOLAS projects of ICSU-SCOR and Future Earth. This knowledge gets assessed in the area of climate by the IPCC and biodiversity by the IPBES processes. The recently released first World Ocean Assessment focuses more on ecosystem services and there is an expectation that the Sustainable Development Goals and in particular Goal 14 on the Ocean and Seas will generate new demands for integrated ocean observing from Climate to Fish and from Ocean Resources to Safe Navigation and on a healthy, productive and enjoyable ocean in more general terms. In recognition of those increasing needs for integrated ocean information we have recently launched the Horizon 2020 AtlantOS project to promote the transition from a loosely-coordinated set of existing ocean observing activities to a more integrated, more efficient, more sustainable and fit-for-purpose Atlantic Ocean Observing System. AtlantOS takes advantage of the Framework for Ocean observing that provided strategic guidance for the design of the project and its outcome. AtlantOS will advance the requirements and systems design, improving the readiness of observing networks and data systems, and engaging stakeholders around the Atlantic. AtlantOS will bring Atlantic nations together to strengthen their complementary contributions to and benefits from the internationally coordinated Global Ocean Observing System (GOOS) and the Blue Planet Initiative of the Global Earth Observation System of Systems (GEOSS). AtlantOS will fill gaps of the in-situ observing system networks and will ensure that their data are readily accessible and useable. AtlantOS will demonstrate the utility of

  1. The Sodankylä in-situ soil moisture observation network: an example application to Earth Observation data product evaluation

    NASA Astrophysics Data System (ADS)

    Ikonen, J.; Vehviläinen, J.; Rautiainen, K.; Smolander, T.; Lemmetyinen, J.; Bircher, S.; Pulliainen, J.

    2015-12-01

    Soil moisture is one of the main drivers in water, energy, and carbon cycles. Both latent and sensible heat fluxes, governing the air temperature and humidity boundary layer over land, are affected by variations in soil moisture. During the last decade there has been considerable development in remote sensing techniques relating to soil moisture retrievals over large areas. Within the framework of the European Space Agency's (ESA) Climate Change Initiative (CCI) a new soil moisture product has been generated, merging different satellite-based surface soil moisture based products. Such remotely sensed data needs to be validated by means of in-situ observations in different climatic regions. In that context, a comprehensive, distributed network of in-situ measurement stations gathering information on soil moisture, as well as soil temperature, has been set up in recent years at the Finnish Meteorological Institute's (FMI) Sodankylä Arctic research station. The network forms a (CAL-VAL) reference site and is used as a tool to evaluate the validity of satellite retrievals of soil properties. In this paper we present the Sodankylä CAL-VAL reference site soil moisture observation network. The procedures for choosing the representative sites for individual soil moisture network stations are discussed, as well as the development of a weighted average of top layer (5-10 cm) soil moisture over the study area. Comparisons of top layer soil moisture around the Sodankylä CAL-VAL site between the years 2012 and 2014 using ESA CCI soil moisture data against in-situ network observations were conducted. The comparisons were made against a single CCI data product pixel encapsulating the Sodankylä observation sites. Comparisons have been made against both daily CCI soil moisture estimates and against weekly running average values. Soil moisture comparisons are only conducted during snow free and thawed periods, as the presence of snow and soil frost interfere with Earth

  2. Comparison of optical and microphysical properties of pure Saharan mineral dust observed with AERONET Sun photometer, Raman lidar, and in situ instruments during SAMUM 2006

    NASA Astrophysics Data System (ADS)

    Müller, D.; Lee, K.-H.; Gasteiger, J.; Tesche, M.; Weinzierl, B.; Kandler, K.; Müller, T.; Toledano, C.; Otto, S.; Althausen, D.; Ansmann, A.

    2012-04-01

    The Saharan Mineral Dust Experiment (SAMUM) 2006, Morocco, aimed at the characterization of optical, physical, and radiative properties of Saharan dust. AERONET Sun photometer, several lidars (Raman and high-spectral-resolution instruments), and airborne and ground-based in situ instruments provided us with a comprehensive set of data on particle-shape dependent and particle-shape independent dust properties. We compare 4 measurement days in detail, and we carry out a statistical analysis for some of the inferred data products for the complete measurement period. Particle size distributions and complex refractive indices inferred from the Sun photometer observations and measured in situ aboard a research aircraft show systematic differences. We find differences in the wavelength-dependence of single-scattering albedo, compared to light-scattering computations that use data from SOAP (spectral optical absorption photometer). AERONET data products of particle size distribution, complex refractive index, and axis ratios were used to compute particle extinction-to-backscatter (lidar) ratios and linear particle depolarization ratios. We find differences for these parameters to lidar measurements of lidar ratio and particle depolarization ratio. Differences particularly exist at 355 nm, which may be the result of differences of the wavelength-dependent complex refractive index that is inferred by the methods employed in this field campaign. We discuss various error sources that may lead to the observed differences.

  3. Comparative study of aerosols observed by YAG lidar and airborne detectors

    NASA Technical Reports Server (NTRS)

    Hirono, M.; Fujiwara, M.; Shibata, T.

    1985-01-01

    The causal relationships of very large (tropical) volcanic eruptions and El Nino Southern Oscillations (ENSO) based on the unequal atmospheric heating by aerosols observed by lidar and airborne detectors are discussed.

  4. In Situ Observations of Dissolved Manganese in Hydrothermal Vent Plumes at Mariana Trough.

    NASA Astrophysics Data System (ADS)

    Okamura, K.; Yanai, K.; Sohrin, Y.; Ishibashi, J.; Watanabe, M.; Ura, T.

    2004-12-01

    We studied for hydrothermal plumes in Mariana Trough by using in situ Mn-Fe analyzers (GAMOS-II). GAMOS-II (Geochemical Anomalies MOnitoring system) is an in-situ chemical analyzer used to detect manganese and/or iron anomalies in neutrally buoyant plumes and to map distributions in bottom seawater over vent fields. During TN167 (ROV ROPOS / R/V Thomas G Thompson) cruise, GAMOS-II measurements were conducted for plume observation at the Yamanaka and Fryer sites. GAMOS-II was attached on the sampling stage of the ROPOS at dive #'777. ROPOS arrived at the bottom at 0:50, and left the bottom at 10:55. Active manganese and temperature anomalies were detected around 2:00 - 5:00 and 7:00 - 11:00, when the ROPOS passed through hydrothermally active areas. The anomaly of temperature and manganese concentration was observed coincidentally, but the relation ship is not consistently proportional. Wide variation in Mn vs. temperature ratio implies diversity between geochemical flux and heat flux depending on the type of venting in the hydrothermal sites. During KH-04-02 Leg2 (AUV r2D4 / R/V Hakuho-Maru) cruise, GAMOS-II measurements were also conducted for plume observation at NW ROTA #1 seamount. GAMOS-II was attached in the AUV r2D4 with CTD. During four successive dives, the fine structure of hydrothermal plumes changed drastically, probably reflecting temporal variation of hydrothermal activity. Continuous sampling by using GAMOS-II was also done successfully. We will also discuss about the data of this continuous sampling.

  5. Prediction of Geomagnetic Storm Strength from Inner Heliospheric In Situ Observations

    NASA Astrophysics Data System (ADS)

    Kubicka, M.; Möstl, C.; Amerstorfer, T.; Boakes, P. D.; Feng, L.; Eastwood, J. P.; Törmänen, O.

    2016-12-01

    Prediction of the effects of coronal mass ejections (CMEs) on Earth strongly depends on knowledge of the interplanetary magnetic field southward component, B z . Predicting the strength and duration of B z inside a CME with sufficient accuracy is currently impossible, forming the so-called B z problem. Here, we provide a proof-of-concept of a new method for predicting the CME arrival time, speed, B z , and resulting disturbance storm time (Dst) index on Earth based only on magnetic field data, measured in situ in the inner heliosphere (<1 au). On 2012 June 12-16, three approximately Earthward-directed and interacting CMEs were observed by the Solar Terrestrial Relations Observatory imagers and Venus Express (VEX) in situ at 0.72 au, 6° away from the Sun-Earth line. The CME kinematics are calculated using the drag-based and WSA-Enlil models, constrained by the arrival time at VEX, resulting in the CME arrival time and speed on Earth. The CME magnetic field strength is scaled with a power law from VEX to Wind. Our investigation shows promising results for the Dst forecast (predicted: -96 and -114 nT (from 2 Dst models); observed: -71 nT), for the arrival speed (predicted: 531 ± 23 km s-1 observed: 488 ± 30 km s-1), and for the timing (6 ± 1 hr after the actual arrival time). The prediction lead time is 21 hr. The method may be applied to vector magnetic field data from a spacecraft at an artificial Lagrange point between the Sun and Earth or to data taken by any spacecraft temporarily crossing the Sun-Earth line.

  6. Microstructural Changes in MBE Growth of Low-Temperature Gallium Arsenide Observed by in Situ Ellipsometry

    NASA Astrophysics Data System (ADS)

    Eyink, Kurt Gerard

    1995-01-01

    An ellipsometer system has been developed for in-situ monitoring of III-V semiconductor growth using molecular beam epitaxy. Included as part of this work, a software package was developed for the calibration, acquisition, display and modeling of ellipsometry data. This calibration software addresses the arbitrary orientations of the analyzer and polarizer components that are present in the mounting of the ellipsometer on the MBE system. In addition, this package calculated the trajectory followed during the growth of a homogeneous film. The materials used in the modeling are restricted to either an isotropic material or a uniaxial material with the optic axis oriented normal to the surface. External to the real-time software package, a general scheme for the analysis of ellipsometric data was developed using MATLAB. The ellipsometer described above was utilized to reproducibly grow and monitor the growth of low temperature (LT) GaAs films in-situ. In particular the capping of GaAs(001) with As was monitored and a method was developed which could be used to characterize the growth temperature of GaAs in the vicinity of 190^circ C. This method utilizes the temperature for the formation of a thin film of As on GaAs(001). Using this technique to set the growth conditions, LT-GaAs films were grown and monitored in real-time with the ellipsometer and characterized ex-situ with X-ray diffraction (XRD) and transmission electron microscopy (TEM.) The ellipsometry data allowed for the observation of the formation of the epitaxial LT-GaAs film and a subsequent region of changing dielectric properties. These results are correlated with observation in double crystal X-ray diffraction (DXRD) and TEM analysis, showing that the refractive index can be used to indicate the composition of the LT-GaAs films and that the ellipsometer can observe the breakdown in the crystallinity of the LT-GaAs layers.

  7. IBEX: The Evolving Global View and Synergies with In Situ Voyager Observations

    NASA Astrophysics Data System (ADS)

    McComas, D. J.

    2015-12-01

    The Interstellar Boundary Explorer (IBEX) has now returned nearly seven years of observations, which comprise 14 full sets of energy resolved all-sky maps and provide the global view of our Sun's interaction with very local part of the galaxy. With such a long baseline of observations, we are able to examine time variations in the outer heliosphere as it responds to both 11-year solar cycle variations and longer term secular evolution of the three dimensional solar wind. Now that we have collected over half a solar cycle of observations, IBEX is beginning to show us how the heliosphere - our home in the galaxy - varies in time as well as space. In this talk we present the most recent observations and review some other recent discoveries from IBEX. We also examine the synergy between the global view provided by IBEX and the in situ observations form the Voyager 1 and 2 spacecraft. Finally, we discuss the incredible improvement in interstellar observations - and our understanding of the local interstellar medium - that the Interstellar Mapping and Acceleration Probe (IMAP) will provide.

  8. Solid-state synthesis of LiBD(4) observed by in situ neutron diffraction.

    PubMed

    Remhof, A; Friedrichs, O; Buchter, F; Mauron, Ph; Züttel, A; Wallacher, D

    2008-10-14

    The synthesis of Li[(11)BD(4)] from LiB and D(2) (p = 180 bar) is investigated by in situ neutron diffraction. The onset of the Li[(11)BD(4)] formation is observed far below the temperatures reported so far for the reaction from the pure elements, indicative of a lower activation barrier. We attribute the improved formation behavior to the breaking of the rigid boron lattice and intermixing of the elements on an atomic level when forming the binary compound LiB. The reaction starts with the decomposition of the initial LiB compound and the formation of LiD. At 623 K LiBD(4) starts to form. However, under the given experimental conditions (maximal temperature = 773 K) a complete reaction was not achieved; there is still residual LiD present.

  9. Direct observation of catalytic oxidation of particulate matter using in situ TEM

    PubMed Central

    Kamatani, Kohei; Higuchi, Kimitaka; Yamamoto, Yuta; Arai, Shigeo; Tanaka, Nobuo; Ogura, Masaru

    2015-01-01

    The ability to observe chemical reactions at the molecular level convincingly demonstrates the physical and chemical phenomena occurring throughout a reaction mechanism. Videos obtained through in situ transmission electron microscopy (TEM) revealed the oxidation of catalytic soot under practical reaction conditions. Carbon oxidation reactions using Ag/SiO2 or Cs2CO3/nepheline catalysts were performed at 330 °C under an O2 flow of 0.5 Pa in the TEM measurement chamber. Ag/SiO2 catalyzed the reaction at the interface of the mobile Ag species and carbon, while the Cs species was fixed on the nepheline surface during the reaction. In the latter case, carbon particles moved, remained attached to the Cs2CO3/nepheline surface, and were consumed at the interface by the oxidation reaction. Using this technique, we were able to visualize such mobile and immobile catalysis according to different mechanisms. PMID:26154580

  10. In-Situ Observation of Membrane Protein Folding during Cell-Free Expression

    PubMed Central

    Fitter, Jörg; Büldt, Georg; Heberle, Joachim; Schlesinger, Ramona; Ataka, Kenichi

    2016-01-01

    Proper insertion, folding and assembly of functional proteins in biological membranes are key processes to warrant activity of a living cell. Here, we present a novel approach to trace folding and insertion of a nascent membrane protein leaving the ribosome and penetrating the bilayer. Surface Enhanced IR Absorption Spectroscopy selectively monitored insertion and folding of membrane proteins during cell-free expression in a label-free and non-invasive manner. Protein synthesis was performed in an optical cell containing a prism covered with a thin gold film with nanodiscs on top, providing an artificial lipid bilayer for folding. In a pilot experiment, the folding pathway of bacteriorhodopsin via various secondary and tertiary structures was visualized. Thus, a methodology is established with which the folding reaction of other more complex membrane proteins can be observed during protein biosynthesis (in situ and in operando) at molecular resolution. PMID:26978519

  11. In situ observation of the ultrafast lattice dynamics of graphite under ion irradiation

    NASA Astrophysics Data System (ADS)

    Ishioka, Kunie; Hase, Muneaki; Kitajima, Masahiro

    2004-05-01

    We develop a pump-probe experiment system, in which vibrational dynamics of a solid sample under ion irradiation can be measured in real time. In situ observation enables us to monitor small changes induced by ion irradiation, without being influenced by the irreproducibility of the sample quality or the experimental configuration. We apply the experimental system to investigate the femtosecond dynamics of the coherent E2 g1 phonon of graphite under 5 keV He + irradiation. A slight decrease in the dephasing rate of the phonon at the initial stage, as well as a downshift followed by an upshift of the phonon frequency, are clearly demonstrated, all of which were ambiguous in the ex situ experiment due to the poor reproducibility of the surface quality. This technique could also be applied to study femtosecond vibrational dynamics in real time during thermal annealing, film deposition with e.g. ablation and sputter, and molecular adsorption on substrates.

  12. An airborne infrared spectrometer for solar eclipse observations

    NASA Astrophysics Data System (ADS)

    Samra, Jenna; Cheimets, Peter; DeLuca, Edward; Galeros, John; Gauron, Thomas; Golub, Leon; Guth, Giora; Hertz, Edward; Judge, Philip; Koutchmy, Serge; Marquez, Vanessa

    2016-08-01

    This paper presents the design of an innovative solar spectrometer that will y on the NSF/NCAR Gulfstream V High-Performance Instrumented Airborne Platform for Environmental Research (GV HIAPER) during the 2017 solar eclipse. The airborne infrared spectrometer (AIR-Spec) is groundbreaking in two aspects: it will image infrared coronal emission lines that have never been measured, and it will bring high resolution imaging to GV HIAPER. The instrument development faces the challenges of achieving adequate resolution and signal-to-noise ratio in a compact package mounted to a noisy moving platform. To ensure that AIR-Spec meets its research goals, the instrument is undergoing pre-flight modeling and testing. The results are presented with reference to the instrument requirements.

  13. Deep-sea macrourid fishes scavenge on plant material: Evidence from in situ observations

    NASA Astrophysics Data System (ADS)

    Jeffreys, Rachel M.; Lavaleye, Marc S. S.; Bergman, Magda J. N.; Duineveld, Gerard C. A.; Witbaard, Rob; Linley, Thom

    2010-04-01

    Deep-sea benthic communities primarily rely on an allochthonous food source. This may be in the form of phytodetritus or as food falls e.g. sinking carcasses of nekton or debris of marine macrophyte algae. Deep-sea macrourids are the most abundant demersal fish in the deep ocean. Macrourids are generally considered to be the apex predators/scavengers in deep-sea communities. Baited camera experiments and stable isotope analyses have demonstrated that animal carrion derived from the surface waters is an important component in the diets of macrourids; some macrourid stomachs also contained vegetable/plant material e.g. onion peels, oranges, algae. The latter observations led us to the question: is plant material an attractive food source for deep-sea scavenging fish? We simulated a plant food fall using in situ benthic lander systems equipped with a baited time-lapse camera. Abyssal macrourids and cusk-eels were attracted to the bait, both feeding vigorously on the bait, and the majority of the bait was consumed in <30 h. These observations indicate (1) plant material can produce an odour plume similar to that of animal carrion and attracts deep-sea fish, and (2) deep-sea fish readily eat plant material. This represents to our knowledge the first in situ documentation of deep-sea fish ingesting plant material and highlights the variability in the scavenging nature of deep-sea fishes. This may have implications for food webs in areas where macrophyte/seagrass detritus is abundant at the seafloor e.g. canyon systems and continental shelves close to seagrass meadows (Bahamas and Mediterranean).

  14. Airborne in-situ investigations of the Eyjafjallajökull volcanic ash plume on Iceland and over north-western Germany with light aircrafts and optical particle counters

    NASA Astrophysics Data System (ADS)

    Weber, K.; Eliasson, J.; Vogel, A.; Fischer, C.; Pohl, T.; van Haren, G.; Meier, M.; Grobéty, B.; Dahmann, D.

    2012-03-01

    During the time period of the eruption of the Icelandic volcano Eyjafjallajökull in April/May 2010 the Duesseldorf University of Applied Sciences has performed 14 research flights in situations with and without the volcanic ash plume over Germany. In parallel to the research flights in Germany three measurement flights have been performed by the University of Iceland in May 2010 over the western part of Iceland. During two of these flights the outskirts of the eruption plume were entered directly, delivering most direct measurements within the eruption plume during this eruptive event. For all the measurement flights reported here, light durable piston-motor driven aircrafts were used, which were equipped with optical particle counters for in-situ measurements. Real-time monitoring of the particle concentrations was possible during the flights. As different types of optical particle counters have been used in Iceland and Germany, the optical particle counters have been re-calibrated after the flights to the same standard using gravimetric reference methods and original Eyjafjallajökull volcanic ash samples. In-situ measurement results with high spatial resolution, directly from the eruption plume in Iceland as well as from the dispersed and several days old plume over Germany, are therefore presented here for the first time. They are normalized to the same ash concentration calibration standard. Moreover, airborne particles could be sampled directly out of the eruption plume in Iceland as well as during the flights over Germany. During the research flights over Iceland from 9 May 2011 to 11 May 2011 the ash emitted from the vent of the volcano turned out to be concentrated in a narrow well-defined plume of about 10 km width at a distance of 45-60 km away from the vent. Outside this plume the airborne ash concentrations could be proved to be below 50 μg m -3 over western Iceland. However, by entering the outskirts of the plume directly the research aircraft could

  15. Global runoff estimates derived from GRACE dataset and in situ observations

    NASA Astrophysics Data System (ADS)

    Chandanpurkar, H. A.; Famiglietti, J. S.; Reager, J. T.; David, C. H.; Syed, T. H.

    2012-12-01

    Global in situ measurements of river discharge from streamflow gauge-stations are available with some consistency for the past several decades. However, the gauge-stations suffer from three major limitations: 1. Lack of regular maintenance and consequent data gaps; 2. Inadequate density of the gauge-stations in the delta regions at the continental margins; and 3. No representation of the sub-surface runoff. Since 2002, Gravity Recovery and Climate Experiment (GRACE) mission has been providing monthly datasets of terrestrial water storage anomaly that can be used to derive runoff values when combined with an atmospheric water balance reanalysis dataset during the last decade. In this research, we compare the GRACE dataset with the corresponding streamflow observations for the world's major river basins. Based on this comparison, we calculate a correction factor to the streamflow observations and estimate adjustment from various limitations on accuracy, from both the GRACE derived runoff estimates as well as those associated with the gauge-station observations, using Bayesian Model Averaging technique. The correction factor is assigned separately for major river basins. Then we apply these correction factors to the streamflow observations outside of the GRACE dataset to produce a gapless, extended time series of global river runoff providing the longevity of the streamflow observations and the improved accuracy due to the GRACE dataset.

  16. Comparisons of cirrus cloud properties between polluted and pristine air based on in-situ observations from the NSF HIPPO, EU INCA and NASA ATTREX campaigns

    NASA Astrophysics Data System (ADS)

    Diao, M.; Schumann, U.; Jensen, J. B.; Minikin, A.

    2015-12-01

    The radiative forcing of cirrus clouds is influenced by microphysical (e.g., ice crystal number concentration and size distribution) and macroscopic properties. Currently it is still unclear how the formation of cirrus clouds and their microphysical properties are influenced by anthropogenic emissions. In this work, we use airborne in-situ observations to compare cirrus cloud properties between polluted and pristine regions. Our dataset includes: the NSF HIAPER Pole-to-Pole Observations (HIPPO) Global campaign (2009-2011), the EU Interhemispheric Differences In Cirrus Properties from Anthropogenic Emissions (INCA) campaign (2000) and the NASA Airborne Tropical Tropopause Experiment (ATTREX) campaign (2014). The combined dataset include observations of both extratropical (HIPPO and INCA) and tropical (ATTREX) cirrus, over the Northern and Southern Hemispheres. We use the in-situ measured carbon monoxide (CO) mixing ratio as a pollution indicator, and compare ice microphysical properties (i.e., ice crystal number concentration (Nc) and number-weighted mean diameter (Dc)) between air masses with higher and lower CO. All analyses are restricted to T ≤ -40°C. By analyzing ice crystals (Fast-2DC, 87.5-1600 µm) in HIPPO, we found that Dc decreases with increasing CO concentration at multiple constant pressure levels. In addition, analysis of INCA data shows that Nc and extinction of small ice particles (FSSP 3-20 µm) increases with increasing CO. Particles < 87.5 µm in Fast-2DC data are not considered due to uncertainty in sample volume, and the FSSP measurements are subject to possible shattering. We further analyze the ice crystals (SPEC FCDP, 1-50 µm) in the tropical tropopause layer in ATTREX. At -70°C to -90°C, we found that the average Nc (Dc) increases (decreases) at higher CO. Overall, our results suggest that extratropical and tropical cirrus are likely to have more numerous small ice particles, when sampled in the more polluted background. Back

  17. Conjugate In-situ and Incoherent Scatter Radar Observations of Radiation Belt Loss Mechanisms.

    NASA Astrophysics Data System (ADS)

    Kaeppler, S. R.; Jaynes, A. N.; Sanchez, E. R.; Nicolls, M. J.; Varney, R. H.; Marshall, R. A.

    2015-12-01

    We present results from conjugate observations between the Radiation Belt Storms Probe (RBSP) and the Poker Flat Incoherent Scatter Radar (PFISR) of energetic radiation belt precipitation. A key objective of the RBSP mission is to understand loss mechanisms of energetic particles from the radiation belt. The relative contribution from plasma waves (e.g., EMIC, hiss, chorus, and etc.) that pitch angle scatter particles into the loss cone remains an open scientific question. Rigorous experimental validation of these mechanisms is difficult to achieve because nearly simultaneous conjugate observations of in-situ pitch angle scattering and precipitation into the atmosphere are required. One ground-based signature of energetic precipitation is enhanced ionization and electron density at D-region altitudes. Incoherent scatter radar is a powerful remote sensing technique that is sensitive to electron density enhancements. By measuring the altitude profiles of ionization we infer the flux of particles precipitating into the atmosphere. PFISR observations show frequent occurrence of D-region ionization during both quiet-time and storm-time conditions. We present results from two events when the foot-points of the RBSP satellite were within 500 km of PFISR: a quiet-time event on January 13, 2015, and a storm-time event on April 16, 2015. PFISR observations of the D-region ionization signatures are presented, along with simultaneous conjugate RBSP observations of the magnetic field, electric field, and electron flux. Plasma waves are identified using the electric and magnetic field data, and evaluated as possible pitch angle scattering mechanisms. A direct comparison between the measured fluxes and loss cone fluxes predicted by theoretical wave-particle diffusion rates into the loss cone is used to test the validity of particle loss mechanisms predicted by the different theories. Preliminary results are presented of PFISR inversions of the D-region ionization to quantify the

  18. High-resolution in situ observations of electron precipitation-causing EMIC waves

    DOE PAGES

    Rodger, Craig J.; Hendry, Aaron T.; Clilverd, Mark A.; ...

    2015-11-21

    Electromagnetic ion cyclotron (EMIC) waves are thought to be important drivers of energetic electron losses from the outer radiation belt through precipitation into the atmosphere. While the theoretical possibility of pitch angle scattering-driven losses from these waves has been recognized for more than four decades, there have been limited experimental precipitation observations to support this concept. We have combined satellite-based observations of the characteristics of EMIC waves, with satellite and ground-based observations of the EMIC-induced electron precipitation. In a detailed case study, supplemented by an additional four examples, we are able to constrain for the first time the location, size,more » and energy range of EMIC-induced electron precipitation inferred from coincident precipitation data and relate them to the EMIC wave frequency, wave power, and ion band of the wave as measured in situ by the Van Allen Probes. As a result, these observations will better constrain modeling into the importance of EMIC wave-particle interactions.« less

  19. High-resolution in situ observations of electron precipitation-causing EMIC waves

    SciTech Connect

    Rodger, Craig J.; Hendry, Aaron T.; Clilverd, Mark A.; Kletzing, Craig A.; Brundell, James B.; Reeves, Geoffrey D.

    2015-11-21

    Electromagnetic ion cyclotron (EMIC) waves are thought to be important drivers of energetic electron losses from the outer radiation belt through precipitation into the atmosphere. While the theoretical possibility of pitch angle scattering-driven losses from these waves has been recognized for more than four decades, there have been limited experimental precipitation observations to support this concept. We have combined satellite-based observations of the characteristics of EMIC waves, with satellite and ground-based observations of the EMIC-induced electron precipitation. In a detailed case study, supplemented by an additional four examples, we are able to constrain for the first time the location, size, and energy range of EMIC-induced electron precipitation inferred from coincident precipitation data and relate them to the EMIC wave frequency, wave power, and ion band of the wave as measured in situ by the Van Allen Probes. As a result, these observations will better constrain modeling into the importance of EMIC wave-particle interactions.

  20. In situ observation of stomatal movements and gas exchange of Aegopodium podagraria L. in the understorey.

    PubMed

    Kaiser, H; Kappen, L

    2000-10-01

    Observations of stomata in situ while simultaneously measuring CO(2) gas exchange and transpiration were made in field experiments with Aegopodium podagraria in a highly variable light climate in the understorey of trees. The low background photosynthetic photon flux density (PPFD) caused a slight opening of the stomata and no visible response to sporadic lightflecks. However, if lightflecks were frequent and brighter, slow opening movements were observed. Small apertures were sufficient to allow maximal photosynthetic rates. Therefore, the small apertures observed in low light usually only caused minor stomatal limitations of lightfleck photosynthesis. The response of stomata to step-wise changes in PPFD under different levels of leaf to air vapour pressure difference (Delta(W)) was observed under controlled conditions. High Delta(W) influenced the stomatal response only slightly by reducing stomatal aperture in low light and causing a slight reduction in the initial capacity to utilize high PPFD levels. Under continuous high PPFD, however, stomata opened to the same degree irrespective of Delta(W). Under high Delta(W), opening and closing responses to PPFD-changes were faster, which enabled a rapid removal of the small stomatal limitations of photosynthesis initially present in high Delta(W) after longer periods in low light. It is concluded that A. podagraria maintains a superoptimal aperture in low light which leads to a low instantaneous water use efficiency, but allows an efficient utilization of randomly occurring lightflecks.

  1. Parameterization of marine stratus microphysics based on in situ observations: Implications for GCMs

    SciTech Connect

    Gultepe, I.; Isaac, G.A.; Leaitch, W.R.; Banic, C.M.

    1996-02-01

    Airborne observations conducted in marine stratus over the east coast of Canada during the North Atlantic Regional Experiment in the summer of 1993 are used to develop cloud microphysical parameterization schemes for general circulation models. Observations of cloud droplet number concentration (N{sub d}), interstitial aerosol number concentration, temperature, verticle air velocity (w), and liquid water content (LWC) are considered, as well as determination of the effective radius (r{sub eff}) and total particle concentration (interstitial aerosol + cloud droplet). Statistical techniques are used to obtain regression equations among the above parameters. For individual clouds, an inverse relationship between the interstitial aerosol concentration and droplet concentration is always observed. In general, variations in r{sub eff} are determined by N{sub d} as much as by LWC. The regression equations are compared with current parameterizations for GCMs. Results showed that multiple relationships are present among N{sub d}, N{sub t}, and w; and r{sub eff}, LWC, and N{sub d}. 37 refs., 12 figs., 3 tabs.

  2. Intermittency of magnetic field turbulence: Astrophysical applications of in-situ observations

    NASA Astrophysics Data System (ADS)

    Zelenyi, Lev M.; Bykov, Andrei M.; Uvarov, Yury A.; Artemyev, Anton V.

    2015-08-01

    We briefly review some aspects of magnetic turbulence intermittency observed in space plasmas. Deviation of statistical characteristics of a system (e.g. its high statistical momenta) from the Gaussian can manifest itself as domination of rare large intensity peaks often associated with the intermittency in the system's dynamics. Thirty years ago, Zeldovich stressed the importance of the non-Gaussian appearance of the sharp values of vector and scalar physical parameters in random media as a factor of magnetic field amplification in cosmic structures. Magnetic turbulence is governing the behavior of collisionless plasmas in space and especially the physics of shocks and magnetic reconnections. Clear evidence of intermittent magnetic turbulence was found in recent in-situ spacecraft measurements of magnetic fields in the near-Earth and interplanetary plasma environments. We discuss the potentially promising approaches of incorporating the knowledge gained from spacecraft in-situ measurements into modern models describing plasma dynamics and radiation in various astrophysical systems. As an example, we discuss supernova remnants (SNRs) which are known to be the sources of energy, momentum, chemical elements, and high-energy cosmic rays (CRs) in galaxies. Supernova shocks accelerate charged particles to very high energies and may strongly amplify turbulent magnetic fields via instabilities driven by CRs. Relativistic electrons accelerated in SNRs radiate polarized synchrotron emission in a broad range of frequencies spanning from the radio to gamma-rays. We discuss the effects of intermittency of magnetic turbulence on the images of polarized synchrotron X-ray emission of young SNRs and emission spectra of pulsar wind nebula.

  3. Validation of two gridded soil moisture products over India with in-situ observations

    NASA Astrophysics Data System (ADS)

    Unnikrishnan, C. K.; George, John P.; Lodh, Abhishek; Maurya, Devesh Kumar; Mallick, Swapan; Rajagopal, E. N.; Mohandas, Saji

    2016-07-01

    Surface level soil moisture from two gridded datasets over India are evaluated in this study. The first one is the UK Met Office (UKMO) soil moisture analysis produced by a land data assimilation system based on Extended Kalman Filter method (EKF), which make use of satellite observation of Advanced Scatterometer (ASCAT) soil wetness index as well as the screen level meteorological observations. Second dataset is a satellite soil moisture product, produced by National Remote Sensing Centre (NRSC) using passive microwave Advanced Microwave Scanning Radiometer 2 measurements. In-situ observations of soil moisture from India Meteorological Department (IMD) are used for the validation of the gridded soil moisture products. The difference between these datasets over India is minimum in the non-monsoon months and over agricultural regions. It is seen that the NRSC data is slightly drier (0.05%) and UKMO soil moisture analysis is relatively wet during southwest monsoon season. Standard AMSR-2 satellite soil moisture product is used to compare the NRSC and UKMO products. The standard AMSR-2 and UKMO values are closer in monsoon season and AMSR-2 soil moisture is higher than UKMO in all seasons. NRSC and AMSR-2 showed a correlation of 0.83 (significant at 0.01 level). The probability distribution of IMD soil moisture observation peaks at 0.25 m3/m3, NRSC at 0.15 m3/m3, AMSR-2 at 0.25 m3/m3 and UKMO at 0.35 m3/m3 during June-September period. Validation results show UKMO analysis has better correlation with in-situ observations compared to the NRSC and AMSR-2 datasets. The seasonal variation in soil moisture is better represented in UKMO analysis. Underestimation of soil moisture during monsoon season over India in NRSC data suggests the necessity of incorporating the actual vegetation for a better soil moisture retrieval using passive microwave sensors. Both products have good agreement over bare soil, shrubs and grassland compared to needle leaf tree, broad leaf tree and

  4. Airborne Science Program: Observing Platforms for Earth Science Investigations

    NASA Technical Reports Server (NTRS)

    Mace, Thomas H.

    2009-01-01

    This slide presentation reviews the Airborne Science Program and the platforms used for conducting investigations for the Earth System Science. Included is a chart that shows some of the aircraft and the operational altitude and the endurance of the aircraft, views of the Dryden Aircraft Operation Facility, and some of the current aircraft that the facility operates, and the varieties of missions that are flown and the type of instrumentation. Also included is a chart showing the attributes of the various aircraft (i.e., duration, weight for a payload, maximum altitude, airspeed and range) for comparison

  5. In situ alkali-silica reaction observed by x-ray microscopy

    SciTech Connect

    Kurtis, K.E.; Monteiro, P.J.M.; Brown, J.T.; Meyer-Ilse, W.

    1997-04-01

    In concrete, alkali metal ions and hydroxyl ions contributed by the cement and reactive silicates present in aggregate can participate in a destructive alkali-silica reaction (ASR). This reaction of the alkalis with the silicates produces a gel that tends to imbibe water found in the concrete pores, leading to swelling of the gel and eventual cracking of the affected concrete member. Over 104 cases of alkali-aggregate reaction in dams and spillways have been reported around the world. At present, no method exists to arrest the expansive chemical reaction which generates significant distress in the affected structures. Most existing techniques available for the examination of concrete microstructure, including ASR products, demand that samples be dried and exposed to high pressure during the observation period. These sample preparation requirements present a major disadvantage for the study of alkali-silica reaction. Given the nature of the reaction and the affect of water on its products, it is likely that the removal of water will affect the morphology, creating artifacts in the sample. The purpose of this research is to observe and characterize the alkali-silica reaction, including each of the specific reactions identified previously, in situ without introducing sample artifacts. For observation of unconditioned samples, x-ray microscopy offers an opportunity for such an examination of the alkali-silica reaction. Currently, this investigation is focusing on the effect of calcium ions on the alkali-silica reaction.

  6. First in-situ observations of neutral and plasma density fluctuations within a PMSE layer

    NASA Technical Reports Server (NTRS)

    Lubken, Franz-Josef; Lehmacher, Gerald; Blix, Tom; Hoppe, Ulf-Peter; Thrane, Eivind; Cho, John; Swartz, Wesley

    1993-01-01

    The NLC-91 rocket and radar campaign provided the first opportunity for high resolution neutral and plasma turbulence measurements with simultaneous observations of PMSE (Polar Mesospheric Summer Echoes). During the flight of the TURBO payload on August 1, 1991, Cornell University Portable Radar Interferometer (CUPRI) and European Incoherent Scattter facility (EISCAT) observed double PMSE layers located at 86 and 88 km altitude, respectively. Strong neutral density fluctuations were observed in the upper layer but not in the lower layer. The fluctuation spectra of the ions and neutrals within the upper layer are consistent with standard turbulence theories. However, we show that there is no neutral turbulence present in the lower layer and that something else must have been operating here to create the plasma fluctuations and hence the radar echoes. Although the in situ measurements of the electron density fluctuations are much stronger in the lower layer, the higher absolute electron density of the upper layer more than compensated for the weaker fluctuations yielding comparable radar echo powers.

  7. First in-situ observations of neutral and plasma density fluctuations within a PMSE layer

    NASA Astrophysics Data System (ADS)

    Lubken, Franz-Josef; Lehmacher, Gerald; Blix, Tom; Hoppe, Ulf-Peter; Thrane, Eivind; Cho, John; Swartz, Wesley

    1993-10-01

    The NLC-91 rocket and radar campaign provided the first opportunity for high resolution neutral and plasma turbulence measurements with simultaneous observations of PMSE (Polar Mesospheric Summer Echoes). During the flight of the TURBO payload on August 1, 1991, Cornell University Portable Radar Interferometer (CUPRI) and European Incoherent Scattter facility (EISCAT) observed double PMSE layers located at 86 and 88 km altitude, respectively. Strong neutral density fluctuations were observed in the upper layer but not in the lower layer. The fluctuation spectra of the ions and neutrals within the upper layer are consistent with standard turbulence theories. However, we show that there is no neutral turbulence present in the lower layer and that something else must have been operating here to create the plasma fluctuations and hence the radar echoes. Although the in situ measurements of the electron density fluctuations are much stronger in the lower layer, the higher absolute electron density of the upper layer more than compensated for the weaker fluctuations yielding comparable radar echo powers.

  8. Diagnostics of the Tropical Tropopause Layer from in-situ observations and CCM data

    NASA Astrophysics Data System (ADS)

    Palazzi, E.; Fierli, F.; Cairo, F.; Cagnazzo, C.; di Donfrancesco, G.; Manzini, E.; Ravegnani, F.; Schiller, C.; D'Amato, F.; Volk, C. M.

    2009-05-01

    A suite of diagnostics is applied to in-situ aircraft measurements and one Chemistry-Climate Model (CCM) data to characterize the vertical structure of the Tropical Tropopause Layer (TTL). The diagnostics are based on the vertical tracers profiles, relative vertical tracers gradients, and tracer-tracer relationships in the tropical Upper Troposphere/Lower Stratosphere (UT/LS), using tropopause coordinates. Observations come from the four tropical campaigns performed from 1998 to 2006 with the research aircraft Geophysica and have been directly compared to the output of the ECHAM5/MESSy CCM. The model vertical resolution in the TTL allows for appropriate comparison with high-resolution aircraft observations and the diagnostics used highlight common TTL features between the model and the observational data. The analysis of the vertical profiles of water vapour, ozone, and nitrous oxide, in both the observations and the model, shows that concentration mixing ratios exhibit a strong gradient change across the tropical tropopause, due to the role of this latter as a transport barrier and that transition between the tropospheric and stratospheric regimes occurs within a finite layer. The use of relative vertical ozone gradients, in addition to the vertical profiles, helps to highlight the region where this transition occurs and allows to give an estimate of its thickness. The analysis of the CO-O3 and H2O-O3 scatter plots and of the Probability Distribution Function (PDF) of the H2O-O3 pair completes this picture as it allows to better distinguish tropospheric and stratospheric regimes that can be identified, first, by their differing chemical composition. The joint analysis and comparison of observed and modelled data allows us to evaluate the capability of the model in reproducing the observed vertical structure of the TTL and its variability, and also to assess whether observations from particular regions on a monthly timescale can be representative of the fine scale

  9. Clear-Sky Closure Studies of Tropospheric Aerosol and Water Vapor During ACE-2 Using Airborne Sunphotometer, Airborne In-Situ, Space-Borne, and Ground-Based Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Collins, Donald R.; Gasso, Santiago; Oestroem, Elisabeth; Powell, Donna M.; Welton, Ellsworth J.; Durkee, Philip A.; Livingston, John M.; Russell, Philip B.; Flagan, Richard C.; Seinfeld, John H.; Hegg, Dean A.; Noone, Kevin J.; Voss, Kenneth J.; Gordon, Howard R.; Reagan, John A.; Spinhirne, James D.

    2000-01-01

    We report on clear-sky column closure experiments (CLEARCOLUMN) performed in the Canary Islands during the second Aerosol Characterization Experiment (ACE-2) in June/July 1997. We present CLEARCOLUMN results obtained by combining airborne sunphotometer and in-situ (a differential mobility analyzer, three optical particle counters, three nephelometers, and one absorption photometer) measurements taken aboard the Pelican aircraft, space-borne NOAA/AVHRR data and ground-based lidars. A wide range of aerosol types was encountered throughout the ACE-2 area, including background Atlantic marine, European pollution-derived, and (although less frequently than expected) African mineral dust. During the two days discussed here, vertical profiles flown in cloud free air masses revealed three distinctly different layers: a marine boundary layer (MBL) with varying pollution levels, an elevated dust layer, and a very clean layer between the MBL and the dust layer. Based on size-resolved composition information we have established an aerosol model that allows us to compute optical properties of the ambient aerosol using the optical particle counter results. In the dust, the agreement in layer AOD (lambda=380-1060 nm) is 3-8%. In the MBL there is a tendency for the in-situ results to be slightly lower than the sunphotometer measurements (10-17% at lambda=525 nm), but these differences are within the combined error bars of the measurements and computations. Aerosol size-distribudon closure based on in-situ size distributions and inverted sunphotometer extinction spectra has been achieved in the MBL (total surface area and volume agree within 0.2, and 7%, respectively) but not in the dust layer. The fact that the three nephelometers operated at three different relative humidities (RH) allowed to parameterize hygroscopic growth and to therefore estimate optical properties at ambient RH. The parameters derived for different aerosol types are themselves useful for the aerosol modeling

  10. Paddy field mapping and yield estimation by satellite imagery and in situ observations

    NASA Astrophysics Data System (ADS)

    Oyoshi, K.; Sobue, S.

    2011-12-01

    Since Asian countries are responsible for approximately 90% of the world rice production and consumptions, rice is the most significant cereal crop in Asia. In order to ensure food security and take mitigation strategies or policies to manage food shortages, timely and accurate statistics of rice production are essential. It is time and cost consuming work to create accurate statistics of rice production by ground-based measurements. Hence, satellite remote sensing is expected to contribute food security through the systematic collection of food security related information such as crop growth or yield estimation. In 2011, Japan Aerospace Exploration Agency (JAXA) is collaborating with GISTDA (Geo-Informatics and Space Technology Development Agency, Thailand) in research projects of rice yield estimation by integrating satellite imagery and in situ data. Thailand is one of the largest rice production countries and the largest rice exporting country, therefore rice related statistics are imperative for food security and economy in the country. However, satellite observation by optical sensor in tropics including Thailand is highly limited, because the area is frequently covered by cloud. In contrast, Japanese microwave sensor, namely Phased-Array L-Band Synthetic Aperture Radar (PALSAR) on board Advanced Land Observing Satellite (ALOS) is suitable for monitoring cloudy area such as Southeast Asia, because PALSAR can penetrate clouds and collect land-surface information even if the area is covered by cloud. In this study, rice crop yield over Khon Kaen, northeast part of Thailand was estimated by combining satellite imagery and in-situ observation. This study consists of mainly two parts, paddy field mapping and yield estimation by numerical crop model. First, paddy field areas were detected by integrating PALSAR and AVNIR-2 data. PALSAR imagery has much speckle noise and the border of each landcover is ambiguous compared to that of optical sensor. To overcome this

  11. An initial assessment of SMAP soil moisture retrievals using high-resolution model simulations and in situ observations

    NASA Astrophysics Data System (ADS)

    Pan, Ming; Cai, Xitian; Chaney, Nathaniel W.; Entekhabi, Dara; Wood, Eric F.

    2016-09-01

    At the end of its first year of operation, we compare soil moisture retrievals from the Soil Moisture Active Passive (SMAP) mission to simulations from a land surface model with meteorological forcing downscaled from observations/reanalysis and in situ observations from sparse monitoring networks within continental United States (CONUS). The radar failure limits the duration of comparisons for the active and combined products (~3 months). Nevertheless, the passive product compares very well against in situ observations over CONUS. On average, SMAP compares to the in situ data even better than the land surface model and provides significant added value on top of the model and thus good potential for data assimilation. At large scale, SMAP is in good agreement with the model in most of CONUS with less-than-expected degradation over mountainous areas. Lower correlation between SMAP and the model is seen in the forested east CONUS and significantly lower over the Canadian boreal forests.

  12. Optical properties of urban aerosol from airborne and ground-based in situ measurements performed during the Etude et Simulation de la Qualité de l'air en Ile de France (ESQUIF) program

    NASA Astrophysics Data System (ADS)

    Chazette, Patrick; Randriamiarisoa, Hariliva; Sanak, Joseph; Couvert, Pierre; Flamant, Cyrille

    2005-01-01

    Urban aerosol microphysical and optical properties were investigated over the Paris area coupling, for the first time, with dedicated airborne in situ instruments (nephelometer and particle sizers) and active remote sensor (lidar) as well as ground-based in situ instrumentation. The experiment, covering two representative pollution events, was conducted in the framework of the Etude et Simulation de la Qualité de l'air en Ile de France (ESQUIF) program. Pollution plumes were observed under local northerly and southerly synoptic wind conditions on 19 and 31 July 2000, respectively. The 19 July (31 July) event was characterized by north-northwesterly (westerly) advection of polluted (clean) air masses originating from Great Britain (the Atlantic Ocean). The aerosol number size distribution appeared to be composed mainly of two modes in the planetary boundary layer (accumulation and nucleation) and three modes in the surface layer (accumulation, nucleation, and coarse). The characteristics of the size distribution (modal radii and geometric dispersion) were remarkably similar on both days and very coherent with the aerosol optical parameters retrieved from lidar and nephelometer measurements. The city of Paris mainly produces aerosols in the nucleation mode (modal radius of ˜0.03 μm) that have little influence on the aerosol optical properties in the visible spectral range. The latter are largely dominated by the scattering properties of aerosols in the accumulation mode (modal radius of ˜0.12 μm). When the incoming air mass is already polluted (clear), the aerosol in the accumulation mode is shown to be essentially hydrophobic (hydrophilic) in the outgoing air mass.

  13. Seasonal in situ observations of glyoxal and methylglyoxal over the temperate oceans of the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Lawson, S. J.; Selleck, P. W.; Galbally, I. E.; Keywood, M. D.; Harvey, M. J.; Lerot, C.; Helmig, D.; Ristovski, Z.

    2015-01-01

    The dicarbonyls glyoxal and methylglyoxal have been measured with 2,4-dinitrophenylhydrazine (2,4-DNPH) cartridges and high-performance liquid chromatography (HPLC), optimised for dicarbonyl detection, in clean marine air over the temperate Southern Hemisphere (SH) oceans. Measurements of a range of dicarbonyl precursors (volatile organic compounds, VOCs) were made in parallel. These are the first in situ measurements of glyoxal and methylglyoxal over the remote temperate oceans. Six 24 h samples were collected in summer (February-March) over the Chatham Rise in the south-west Pacific Ocean during the Surface Ocean Aerosol Production (SOAP) voyage in 2012, while 34 24 h samples were collected at Cape Grim Baseline Air Pollution Station in the late winter (August-September) of 2011. Average glyoxal mixing ratios in clean marine air were 7 ppt at Cape Grim and 23 ppt over Chatham Rise. Average methylglyoxal mixing ratios in clean marine air were 28 ppt at Cape Grim and 10 ppt over Chatham Rise. The mixing ratios of glyoxal at Cape Grim are the lowest observed over the remote oceans, while mixing ratios over Chatham Rise are in good agreement with other temperate and tropical observations, including concurrent Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations. Methylglyoxal mixing ratios at both sites are comparable to the only other marine methylglyoxal observations available over the tropical Northern Hemisphere (NH) ocean. Ratios of glyoxal : methylglyoxal > 1 over Chatham Rise but < 1 at Cape Grim suggest that a different formation and/or loss processes or rates dominate at each site. Dicarbonyl precursor VOCs, including isoprene and monoterpenes, are used to calculate an upper-estimate yield of glyoxal and methylglyoxal in the remote marine boundary layer and explain at most 1-3 ppt of dicarbonyls observed, corresponding to 10% and 17% of the observed glyoxal and 29 and 10% of the methylglyoxal at Chatham Rise and Cape Grim

  14. Seasonal in situ observations of glyoxal and methylglyoxal over the temperate oceans of the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Lawson, S. J.; Selleck, P. W.; Galbally, I. E.; Keywood, M. D.; Harvey, M. J.; Lerot, C.; Helmig, D.; Ristovski, Z.

    2014-08-01

    Dicarbonyls glyoxal and methylglyoxal have been measured with 2,4-dinitrophenylhydrazine (2,4-DNPH) cartridges and high performance liquid chromatography (HPLC), optimised for dicarbonyl detection, in clean marine air over the temperate Southern Hemisphere (SH) oceans. Measurements of a range of dicarbonyl precursors (volatile organic compounds, VOCs) were made in parallel. These are the first in situ measurements of glyoxal and methylglyoxal over the remote temperate oceans. Six 24 h samples were collected in late summer (February-March) over the Chatham Rise in the South West Pacific Ocean during the Surface Ocean Aerosol Production (SOAP) voyage in 2012, while 34 24 h samples were collected at Cape Grim Baseline Air Pollution Station in late winter (August-September) 2011. Average glyoxal mixing ratios in clean marine air were 7 ppt at Cape Grim, and 24 ppt over Chatham Rise. Average methylglyoxal mixing ratios in clean marine air were 28 ppt at Cape Grim and 12 ppt over Chatham Rise. The mixing ratios of glyoxal at Cape Grim are the lowest observed over the remote oceans, while mixing ratios over Chatham Rise are in good agreement with other temperate and tropical observations, including concurrent MAX-DOAS observations. Methylglyoxal mixing ratios at both sites are comparable to the only other marine methylglyoxal observations available over the tropical Northern Hemisphere (NH) ocean. Ratios of glyoxal : methylglyoxal > 1 over Chatham Rise but < 1 at Cape Grim, suggesting different formation and/or loss processes or rates dominate at each site. Dicarbonyl precursor VOCs, including isoprene and monoterpenes, are used to calculate an upper estimate yield of glyoxal and methylglyoxal in the remote marine boundary layer and explain at most 1-3 ppt of dicarbonyls observed, corresponding to 11 and 17% of the observed glyoxal and 28 and 10% of the methylglyoxal at Chatham Rise and Cape Grim, respectively, highlighting a significant but as yet unknown production

  15. Investigating Baseline, Alternative and Copula-based Algorithm for combining Airborne Active and Passive Microwave Observations in the SMAP Context

    NASA Astrophysics Data System (ADS)

    Montzka, C.; Lorenz, C.; Jagdhuber, T.; Laux, P.; Hajnsek, I.; Kunstmann, H.; Entekhabi, D.; Vereecken, H.

    2015-12-01

    The objective of the NASA Soil Moisture Active & Passive (SMAP) mission is to provide global measurements of soil moisture and freeze/thaw states. SMAP integrates L-band radar and radiometer instruments as a single observation system combining the respective strengths of active and passive remote sensing for enhanced soil moisture mapping. Airborne instruments will be a key part of the SMAP validation program. Here, we present an airborne campaign in the Rur catchment, Germany, in which the passive L-band system Polarimetric L-band Multi-beam Radiometer (PLMR2) and the active L-band system F-SAR of DLR were flown simultaneously on the same platform on six dates in 2013. The flights covered the full heterogeneity of the area under investigation, i.e. all types of land cover and experimental monitoring sites with in situ sensors. Here, we used the obtained data sets as a test-bed for the analysis of three active-passive fusion techniques: A) The SMAP baseline algorithm: Disaggregation of passive microwave brightness temperature by active microwave backscatter and subsequent inversion to soil moisture, B), the SMAP alternative algorithm: Estimation of soil moisture by passive sensor data and subsequent disaggregation by active sensor backscatter and C) Copula-based combination of active and passive microwave data. For method C empirical Copulas were generated and theoretical Copulas fitted both on the level of the raw products brightness temperature and backscatter as well as two soil moisture products. Results indicate that the regression parameters for method A and B are dependent on the radar vegetation index (RVI). Similarly, for method C the best performance was gained by generating separate Copulas for individual land use classes. For more in-depth analyses longer time series are necessary as can obtained by airborne campaigns, therefore, the methods will be applied to SMAP data.

  16. Assessing GOCE Gravity Models using Altimetry and In-situ Ocean Current Observation

    NASA Astrophysics Data System (ADS)

    Knudsen, Per; Andersen, Ole; Honecker, Johanna; Maximenko, Nikolai

    2015-04-01

    The Gravity and steady state Ocean Circulation Explorer (GOCE) satellite mission measures Earth's gravity field with an unprecedented accuracy at short spatial scales. Previous results have demonstrated a significant advance in our ability to determine the ocean's general circulation. The improved gravity models provided by the GOCE mission have enhanced the resolution and sharpened the boundaries of those features and the associated geostrophic surface currents reveal improvements for all of the ocean's current systems. In this study, a series of 23 newer gravity models including observations from GOCE are combined with the DTU13MSS mean sea surface to derive models for the Mean Dynamic Topography (MDT). The series of GOCE based MDT models are compared in regional analyses to identify differences and to quantify quality measures associated with the models. By using Fourier techniques the spectral characteristics are obtained as well as their anisotropic patterns. Then, regional analyses are carried out using in-situ observations of the geostrophic surface currents. This is done to analyse correlations and to derive resolution capacities of the MDT models. Also this information is used as quantified quality measures associated with the 23 GOCE gravity models.

  17. In-situ observation of nucleated polymer crystallization in polyoxymethylene sandwich composites

    NASA Astrophysics Data System (ADS)

    Slouf, Miroslav; Krejcikova, Sabina; Vackova, Tatana; Kratochvil, Jaroslav; Novak, Libor

    2015-03-01

    We introduce a dynamic sandwich method, which can be used for in-situ observation and quantification of polymer crystallization nucleated by micro/nanoparticles. The method was applied on polyoxymethylene (POM) composites with three nucleating agents: talc micropowder (POM/mTalc), chalk nanopowder (POM/nChalk) and titanate nanotubes (POM/TiNT). The nucleating agents were deposited between polymer films, the resulting sandwich samples were consolidated by thermal treatment, and their microtomed cross-sections were observed during isothermal crystallization by polarized light microscopy. As the intensity of polarized light was shown to be proportional to the relative crystallinity, the PLM results could be fitted to Avrami equation and the nucleating activity of all investigated particles could be quantified by means of Avrami parameters (n, k). The crystallization half-times increased reproducibly in the following order: POM/nChalk < POM/mTalc < POM/TiNT ~ POM. For strong nucleating agents (mTalc, nChalk), the crystallization kinetics corresponded to spontaneous crystallization starting from central nucleating layer, which was verified by computer simulations. The results were also confirmed by DSC. We concluded that the sandwich method is an efficient microscopic technique for detailed evaluation of nucleating activity of arbitrary micro/nanoparticles in polymer systems.

  18. The MyOcean Thematic Assembly Centres: Satellite and In-situ Observation Services in Review

    NASA Astrophysics Data System (ADS)

    Hackett, Bruce; Breivik, Lars-Anders; Larnicol, Gilles; Pouliquen, Sylvie; Santoleri, Rosalia; Roquet, Hervé; Stoffelen, Ad

    2015-04-01

    The MyOcean (2009-2012), MyOcean2 (2012-2014) and MyOcean Follow-On (October 2014 - March 2015) projects, respectively funded by the EU's 7th Framework Programme for Research (FP7 2007-2013) and HORIZON 2020 (EU Research and Innovation programme 2014-2020), have been designed to prepare and to lead the demonstration phases of the nascent European Copernicus Marine Environment Monitoring Service (CMS). The observational component of the MyOcean services is embodied in four Thematic Assembly Centres (TACs): Three provide satellite-based products for sea level (SL-TAC), for ocean colour (OC-TAC) and for surface temperature, winds and sea ice (OSI-TAC), while the fourth provides in-situ observations (INS-TAC). All the TAC production is developed from existing capabilities and there is close collaboration with related national and European data providers. Data products include near-real-time data and multi-year reprocessed datasets. Data formatting, dissemination methods and documentation follow uniform MyOcean standards for ease of use. The presentation will track the evolution of the TAC services through the MyOcean projects up to the opening of the CMS.

  19. In situ observation of shear-driven amorphization in silicon crystals

    SciTech Connect

    He, Yang; Zhong, Li; Fan, Feifei; Wang, Chongmin; Zhu, Ting; Mao, Scott X.

    2016-09-19

    Amorphous materials have attracted great interest in the scientific and technological fields. An amorphous solid usually forms under the externally driven conditions of melt-quenching, irradiation and severe mechanical deformation. However, its dynamic formation process remains elusive. Here we report the in situ atomic-scale observation of dynamic amorphization processes during mechanical straining of nanoscale silicon crystals by high resolution transmission electron microscopy (HRTEM). We observe the shear-driven amorphization (SDA) occurring in a dominant shear band. The SDA involves a sequence of processes starting with the shear-induced diamond-cubic to diamond-hexagonal phase transition that is followed by dislocation nucleation and accumulation in the newly formed phase, leading to the formation of amorphous silicon. The SDA formation through diamond-hexagonal phase is rationalized by its structural conformity with the order in the paracrystalline amorphous silicon, which maybe widely applied to diamond-cubic materials. Besides, the activation of SDA is orientation-dependent through the competition between full dislocation nucleation and partial gliding.

  20. In Situ Observation of the Electrochemical Lithiation of a Single SnO2 Nanowire Electrode

    SciTech Connect

    Huang, J Y; Zhong, L; Wang, C M; Sullivan, J P; Xu, W; Zhang, L Q; Mao, S X; Hudak, N S; Liu, X H; Subramanian, A; Fan, H Y; Qi, L A; Kushima, A; Li, J

    2010-12-09

    We report the creation of a nanoscale electrochemical device inside a transmission electron microscope—consisting of a single tin dioxide (SnO{sub 2}) nanowire anode, an ionic liquid electrolyte, and a bulk lithium cobalt dioxide (LiCoO{sub 2}) cathode—and the in situ observation of the lithiation of the SnO{sub 2} nanowire during electrochemical charging. Upon charging, a reaction front propagated progressively along the nanowire, causing the nanowire to swell, elongate, and spiral. The reaction front is a “Medusa zone” containing a high density of mobile dislocations, which are continuously nucleated and absorbed at the moving front. This dislocation cloud indicates large in-plane misfit stresses and is a structural precursor to electrochemically driven solid-state amorphization. Because lithiation-induced volume expansion, plasticity, and pulverization of electrode materials are the major mechanical effects that plague the performance and lifetime of high-capacity anodes in lithium-ion batteries, our observations provide important mechanistic insight for the design of advanced batteries.

  1. Enhanced sulfate formation by nitrogen dioxide: Implications from in situ observations at the SORPES station

    NASA Astrophysics Data System (ADS)

    Xie, Yuning; Ding, Aijun; Nie, Wei; Mao, Huiting; Qi, Ximeng; Huang, Xin; Xu, Zheng; Kerminen, Veli-Matti; Petäjä, Tuukka; Chi, Xuguang; Virkkula, Aki; Boy, Michael; Xue, Likun; Guo, Jia; Sun, Jianning; Yang, Xiuqun; Kulmala, Markku; Fu, Congbin

    2015-12-01

    Investigating sulfate formation processes is important not only for air pollution control but also for understanding the climate system. Although the mechanisms of secondary sulfate production have been widely studied, in situ observational evidence implicating an important role of NO2 in SO2 oxidation in the real atmosphere has been rare. In this study, we report two unique cases, from an intensive campaign conducted at the Station for Observing Regional Processes of the Earth System (SORPES) in East China, showing distinctly different mechanisms of sulfate formation by NO2 and related nitrogen chemistry. The first case occurred in an episode of mineral dust mixed with anthropogenic pollutants and especially high concentrations of NOx. It reveals that NO2 played an important role, not only in surface catalytic reactions of SO2 but also in dust-induced photochemical heterogeneous reactions of NO2, which produced additional sources of OH radicals to promote new particle formation and growth. The second case was caused by aqueous oxidation of S(IV) by NO2 under foggy/cloudy conditions with high NH3 concentration. As a by-product, the formed nitrite enhanced HONO formation and further promoted the gas-phase formation of sulfate in the downwind area. This study highlights the effect of NOx in enhancing the atmospheric oxidizing capacity and indicates a potentially very important impact of increasing NOx on particulate pollution formation and regional climate change in East Asia.

  2. In situ Observation of Calcium Oxide Treatment of Inclusions in Molten Steel by Confocal Microscopy

    NASA Astrophysics Data System (ADS)

    Khurana, Bharat; Spooner, Stephen; Rao, M. B. V.; Roy, Gour Gopal; Srirangam, Prakash

    2017-03-01

    Calcium treatment of aluminum killed steel was observed in situ using high-temperature confocal scanning laser microscope (HT-CSLM). This technique along with a novel experimental design enables continuous observation of clustering behavior of inclusions before and after the calcium treatment. Results show that the increase in average inclusion size in non-calcium-treated condition was much faster compared to calcium-treated condition. Results also show that the magnitude of attractive capillary force between inclusion particles in non-treated condition was about 10-15 N for larger particles (10 µm) and 10-16 N for smaller particles (5 µm) and acting length of force was about 30 µm. In the case of calcium-treated condition, the magnitude and acting length of force was reduced to 10-16 N and 10 µm, respectively, for particles of all sizes. This change in attractive capillary attractive force is due to change in inclusion morphology from solid alumina disks to liquid lens particles during calcium treatment.

  3. In-Situ Observations of a Subglacial Outflow Plume in a Greenland Fjord

    NASA Astrophysics Data System (ADS)

    Mankoff, K. D.; Straneo, F.; Singh, H.; Das, S. B.

    2014-12-01

    We present oceanographic observations collected in and immediately outside of a buoyant, fresh, sediment-laden subglacial outflow plume rising up the marine-terminating front of Sarqardleq Glacier, Greenland (68.9 N, 50.4 W). Subglacial outflow plumes, associated with the discharge at depth of upstream glacial surface melt, entrain the relatively warm fjord waters and are correlated with enhanced submarine melt and increased calving. Few in-situ observations exist due to the challenges of making measurements at the calving front of glaciers. Our data were collected using a small boat, a helicopter, and a JetYak (a remote-controlled jet-ski-powered kayak). Temperature and salinity profiles in, around, and far from the plume are used to described its oceanographic properties, spatial extent, and temporal variability. This plume rises vertically up the ice front expanding laterally and away from the ice, over-shoots its stable isopycnal and reaches the surface. Its surface expression is identified by colder, saltier, sediment-laden water flowing at ~5 m/s away from the ice face. Within ~300 m from the ice it submerges as it seeks buoyant stability.

  4. In-situ TEM observation of dislocation evolution in Kr-irradiated UO2 single crystal

    SciTech Connect

    Lingfeng He; Mahima Gupta; Clarissa A. Yablinsky; Jian Gan; Marquis A. Kirk; Xian-Ming Bai; Janne Pakarinen; Todd R. Allen

    2013-11-01

    In-situ transmission electron microscopy (TEM) observation of UO2 single crystal irradiated with Kr ions at high temperatures was conducted to understand the dislocation evolution due to high-energy radiation. The dislocation evolution in UO2 single crystal is shown to occur as nucleation and growth of dislocation loops at low-irradiation doses, followed by transformation to extended dislocation segments and networks at high doses, as well as shrinkage and annihilation of some loops and dislocations due to high temperature annealing. Generally the trends of dislocation evolution in UO2 are similar under Kr irradiation at different ion energies and temperatures (150 keV at 600 degrees C and 1 MeV at 800 degrees C) used in this work, although the specific dislocation loop size and density are quite different. Interstitial-type dislocation loops with Burgers vector along <110> were observed in the Kr-irradiated UO2.The irradiated specimens were denuded of dislocation loops near the surface.

  5. In situ observation of the electrochemical lithiation of a single SnO₂ nanowire electrode.

    PubMed

    Huang, Jian Yu; Zhong, Li; Wang, Chong Min; Sullivan, John P; Xu, Wu; Zhang, Li Qiang; Mao, Scott X; Hudak, Nicholas S; Liu, Xiao Hua; Subramanian, Arunkumar; Fan, Hongyou; Qi, Liang; Kushima, Akihiro; Li, Ju

    2010-12-10

    We report the creation of a nanoscale electrochemical device inside a transmission electron microscope--consisting of a single tin dioxide (SnO(2)) nanowire anode, an ionic liquid electrolyte, and a bulk lithium cobalt dioxide (LiCoO(2)) cathode--and the in situ observation of the lithiation of the SnO(2) nanowire during electrochemical charging. Upon charging, a reaction front propagated progressively along the nanowire, causing the nanowire to swell, elongate, and spiral. The reaction front is a "Medusa zone" containing a high density of mobile dislocations, which are continuously nucleated and absorbed at the moving front. This dislocation cloud indicates large in-plane misfit stresses and is a structural precursor to electrochemically driven solid-state amorphization. Because lithiation-induced volume expansion, plasticity, and pulverization of electrode materials are the major mechanical effects that plague the performance and lifetime of high-capacity anodes in lithium-ion batteries, our observations provide important mechanistic insight for the design of advanced batteries.

  6. On the Rates of Coronal Mass Ejections: Remote Solar and In Situ Observations

    NASA Technical Reports Server (NTRS)

    Riley, Pete; Schatzman, C.; Cane, H. V.; Richardson, I. G.; Gopalswamy, N.

    2006-01-01

    We compare the rates of coronal mass ejections (CMEs) as inferred from remote solar observations and interplanetary CMEs (ICMEs) as inferred from in situ observations at both 1 AU and Ulyssses from 1996 through 2004. We also distinguish between those ICMEs that contain a magnetic cloud (MC) and those that do not. While the rates of CMEs and ICMEs track each other well at solar minimum, they diverge significantly in early 1998, during the ascending phase of the solar cycle, with the remote solar observations yielding approximately 20 times more events than are seen at 1 AU. This divergence persists through 2004. A similar divergence occurs between MCs and non-MC ICMEs. We argue that these divergences are due to the birth of midlatitude active regions, which are the sites of a distinct population of CMEs, only partially intercepted by Earth, and we present a simple geometric argument showing that the CME and ICME rates are consistent with one another. We also acknowledge contributions from (1) an increased rate of high-latitude CMEs and (2) focusing effects from the global solar field. While our analysis, coupled with numerical modeling results, generally supports the interpretation that whether one observes a MC within an ICME is sensitive to the trajectory of the spacecraft through the ICME (i.e., an observational selection effect), one result directly contradicts it. Specifically, we find no systematic offset between the latitudinal origin of ICMEs that contain MCs at 1 AU in the ecliptic plane and that of those that do not.

  7. Development of a pattern to measure multiscale deformation and strain distribution via in situ FE-SEM observations.

    PubMed

    Tanaka, Y; Naito, K; Kishimoto, S; Kagawa, Y

    2011-03-18

    We investigated a method for measuring deformation and strain distribution in a multiscale range from nanometers to millimeters via in situ FE-SEM observations. A multiscale pattern composed of a grid as well as random and nanocluster patterns was developed to measure the localized deformation at the specimen surface. Our in situ observations of a carbon fiber-reinforced polymer matrix composite with a hierarchical microstructure subjected to loading were conducted to identify local deformation behaviors at various boundaries. We measured and analyzed the multiscale deformation and strain localizations during various stages of loading.

  8. Towards soil property retrieval from space: Proof of concept using in situ observations

    NASA Astrophysics Data System (ADS)

    Bandara, Ranmalee; Walker, Jeffrey P.; Rüdiger, Christoph

    2014-05-01

    Soil moisture is a key variable that controls the exchange of water and energy fluxes between the land surface and the atmosphere. However, the temporal evolution of soil moisture is neither easy to measure nor monitor at large scales because of its high spatial variability. This is mainly a result of the local variation in soil properties and vegetation cover. Thus, land surface models are normally used to predict the evolution of soil moisture and yet, despite their importance, these models are based on low-resolution soil property information or typical values. Therefore, the availability of more accurate and detailed soil parameter data than are currently available is vital, if regional or global soil moisture predictions are to be made with the accuracy required for environmental applications. The proposed solution is to estimate the soil hydraulic properties via model calibration to remotely sensed soil moisture observation, with in situ observations used as a proxy in this proof of concept study. Consequently, the feasibility is assessed, and the level of accuracy that can be expected determined, for soil hydraulic property estimation of duplex soil profiles in a semi-arid environment using near-surface soil moisture observations under naturally occurring conditions. The retrieved soil hydraulic parameters were then assessed by their reliability to predict the root zone soil moisture using the Joint UK Land Environment Simulator model. When using parameters that were retrieved using soil moisture observations, the root zone soil moisture was predicted to within an accuracy of 0.04 m3/m3, which is an improvement of ∼0.025 m3/m3 on predictions that used published values or pedo-transfer functions.

  9. Simultaneous observations of atmospheric tides from combined in situ and remote observations at Mars from the MAVEN spacecraft

    NASA Astrophysics Data System (ADS)

    England, Scott L.; Liu, Guiping; Withers, Paul; Yiǧit, Erdal; Lo, Daniel; Jain, Sonal; Schneider, Nicholas M.; Deighan, Justin; McClintock, William E.; Mahaffy, Paul R.; Elrod, Meredith; Benna, Mehdi; Jakosky, Bruce M.

    2016-04-01

    We report the observations of longitudinal variations in the Martian thermosphere associated with nonmigrating tides. Using the Neutral Gas Ion Mass Spectrometer (NGIMS) and the Imaging Ultraviolet Spectrograph (IUVS) on NASA's Mars Atmosphere and Volatile EvolutioN Mission (MAVEN) spacecraft, this study presents the first combined analysis of in situ and remote observations of atmospheric tides at Mars for overlapping volumes, local times, and overlapping date ranges. From the IUVS observations, we determine the altitude and latitudinal variation of the amplitude of the nonmigrating tidal signatures, which is combined with the NGIMS, providing information on the compositional impact of these waves. Both the observations of airglow from IUVS and the CO2 density observations from NGIMS reveal a strong wave number 2 signature in a fixed local time frame. The IUVS observations reveal a strong latitudinal dependence in the amplitude of the wave number 2 signature. Combining this with the accurate CO2 density observations from NGIMS, this would suggest that the CO2 density variation is as high as 27% at 0-10° latitude. The IUVS observations reveal little altitudinal dependence in the amplitude of the wave number 2 signature, varying by only 20% from 160 to 200 km. Observations of five different species with NGIMS show that the amplitude of the wave number 2 signature varies in proportion to the inverse of the species scale height, giving rise to variation in composition as a function of longitude. The analysis and discussion here provide a roadmap for further analysis as additional coincident data from these two instruments become available.

  10. CAROLS: A New Airborne L-Band Radiometer for Ocean Surface and Land Observations

    PubMed Central

    Zribi, Mehrez; Pardé, Mickael; Boutin, Jacquline; Fanise, Pascal; Hauser, Daniele; Dechambre, Monique; Kerr, Yann; Leduc-Leballeur, Marion; Reverdin, Gilles; Skou, Niels; Søbjærg, Sten; Albergel, Clement; Calvet, Jean Christophe; Wigneron, Jean Pierre; Lopez-Baeza, Ernesto; Rius, Antonio; Tenerelli, Joseph

    2011-01-01

    The “Cooperative Airborne Radiometer for Ocean and Land Studies” (CAROLS) L-Band radiometer was designed and built as a copy of the EMIRAD II radiometer constructed by the Technical University of Denmark team. It is a fully polarimetric and direct sampling correlation radiometer. It is installed on board a dedicated French ATR42 research aircraft, in conjunction with other airborne instruments (C-Band scatterometer—STORM, the GOLD-RTR GPS system, the infrared CIMEL radiometer and a visible wavelength camera). Following initial laboratory qualifications, three airborne campaigns involving 21 flights were carried out over South West France, the Valencia site and the Bay of Biscay (Atlantic Ocean) in 2007, 2008 and 2009, in coordination with in situ field campaigns. In order to validate the CAROLS data, various aircraft flight patterns and maneuvers were implemented, including straight horizontal flights, circular flights, wing and nose wags over the ocean. Analysis of the first two campaigns in 2007 and 2008 leads us to improve the CAROLS radiometer regarding isolation between channels and filter bandwidth. After implementation of these improvements, results show that the instrument is conforming to specification and is a useful tool for Soil Moisture and Ocean Salinity (SMOS) satellite validation as well as for specific studies on surface soil moisture or ocean salinity. PMID:22346599

  11. In situ nanoscale observations of metatorbernite surfaces interacted with aqueous solutions.

    PubMed

    Astilleros, José Manuel; Pinto, André Jorge; Gonçalves, Mário A; Sánchez-Pastor, Nuria; Fernández-Díaz, Lurdes

    2013-03-19

    Metatorbernite (Cu(UO(2))(2)(PO(4))(2)·8H(2)O) has been identified in contaminated sediments as a phase controlling the fate of U. Here, we applied atomic force microscopy (AFM) to observe in situ the interaction between metatorbernite cleavage surfaces and flowing aqueous solutions (residence time = 1 min) with different pHs. In contact with deionized water the features of (001) surfaces barely modify. However, changes are remarkable both under acidic and basic conditions. In acidic solutions (pH = 2.5) metatorbernite surface develops a rough altered layer and large pits nucleate on it. The altered layer shows a low adhesion and is removed by the AFM tip during the scanning. The large pits spread rapidly, at few tens of nm/s, indicating a collapse of the structure. The combination of dissolution and the presence of defects in the metatorbernite structure can explain both the collapse process and the alteration of the surfaces under acidic conditions. Other mechanisms such as ion exchange reactions remain speculative. In NaOH solutions (pH = 11.5) metatorbernite dissolves by formation of etch pits bounded by steps parallel to [100], the direction of the most straight periodic bond chains (PBCs) in metatorbernite structure. These steps retreat at ∼0.15 nm/s. Under these conditions dissolution is promoted by the formation of stable uranyl carbonate complexes in solution.

  12. Integration of space and in situ observations to study global climate change

    NASA Technical Reports Server (NTRS)

    Bengtsson, L.; Shukla, J.

    1988-01-01

    The use of model-based global data sets of atmospheric circulation for studying fundamental dynamical and physical processes is discussed, focusing on limitations of the available model-based data sets. Data from the Global Weather Experiment in 1979 were analyzed by two authorized level IIIb data centers in 1980 and in 1981. The analyses led to difference in data-sparse regions such as the tropics. Study areas which can be addressed by an internally-consistent long-term multivariate data set for the atmospheric circulation are considered, including mean climate, forcing for the ocean models, global hydrological cycle, atmospheric energetics, intraseasonal variability, land surface processes, and structure and variability of vertical velocity, divergence, and diabatic heating. It is concluded that the most comprehensive technique for integrating space and in situ observations to produce this type of data set would be a four-dimensional data assimilation system with a realistic physical model of the type employed in operational numerical weather prediction.

  13. In situ observation of containerless protein crystallization by magnetically levitating crystal growth

    NASA Astrophysics Data System (ADS)

    Maki, Syou; Tanimoto, Yoshifumi; Udagawa, Chikako; Morimoto, Shotaro; Hagiwara, Masayuki

    2016-03-01

    We report on the results of the crystal growth of hen-egg lysozyme by magnetically levitating crystals in a small amount of buffer solution. The concentrations of lysozyme and the precipitating agent (gadolinium chloride) were 6.53 wt % and 0.362 mol/kg, respectively. Gadolinium chloride, which induces the magneto-Archimedes effect, was utilized to levitate the crystals with Bz · (dBz/dz) = 22.46 T2/m, where Bz is the vertical (z) component of the magnetic flux density vector. Although the collected crystals were small, we succeeded in maintaining the levitation of the crystals into a specific place in the liquid phase from the beginning of nucleation. In situ observation revealed that a state of pseudo-weightlessness was generated in the vicinity of the magnet bore edge, and small crystals were concentrated inside the domain moving along an hourglass-shaped surface. We found by numerical computations that the formation of the hourglass-shaped domain is attributable to the radial component of the magnetic force.

  14. Dynamic in situ observation of voltage-driven repeatable magnetization reversal at room temperature.

    PubMed

    Gao, Ya; Hu, Jia-Mian; Nelson, C T; Yang, T N; Shen, Y; Chen, L Q; Ramesh, R; Nan, C W

    2016-03-31

    Purely voltage-driven, repeatable magnetization reversal provides a tantalizing potential for the development of spintronic devices with a minimum amount of power consumption. Substantial progress has been made in this subject especially on magnetic/ferroelectric heterostructures. Here, we report the in situ observation of such phenomenon in a NiFe thin film grown directly on a rhombohedral Pb(Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT) ferroelectric crystal. Under a cyclic voltage applied perpendicular to the PMN-PT without a magnetic field, the local magnetization of NiFe can be repetitively reversed through an out-of-plane excursion and then back into the plane. Using phase field simulations we interpret magnetization reversal as a synergistic effect of the metastable ferroelastic switching in the PMN-PT and an electrically rotatable local exchange bias field arising from the heterogeneously distributed NiO clusters at the interface.

  15. Dynamic in situ observation of voltage-driven repeatable magnetization reversal at room temperature

    NASA Astrophysics Data System (ADS)

    Gao, Ya; Hu, Jia-Mian; Nelson, C. T.; Yang, T. N.; Shen, Y.; Chen, L. Q.; Ramesh, R.; Nan, C. W.

    2016-03-01

    Purely voltage-driven, repeatable magnetization reversal provides a tantalizing potential for the development of spintronic devices with a minimum amount of power consumption. Substantial progress has been made in this subject especially on magnetic/ferroelectric heterostructures. Here, we report the in situ observation of such phenomenon in a NiFe thin film grown directly on a rhombohedral Pb(Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT) ferroelectric crystal. Under a cyclic voltage applied perpendicular to the PMN-PT without a magnetic field, the local magnetization of NiFe can be repetitively reversed through an out-of-plane excursion and then back into the plane. Using phase field simulations we interpret magnetization reversal as a synergistic effect of the metastable ferroelastic switching in the PMN-PT and an electrically rotatable local exchange bias field arising from the heterogeneously distributed NiO clusters at the interface.

  16. [In situ Raman spectroscopic observation of micro-processes of methane hydrate formation and dissociation].

    PubMed

    Liu, Chang-Ling; Ye, Yu-Guang; Meng, Qing-Guo; Lü, Wan-Jun; Wang, Fei-Fei

    2011-06-01

    Micro laser Raman spectroscopic technique was used for in situ observation of the micro-processes of methane hydrate formed and decomposed in a high pressure transparent capillary. The changes in clathrate structure of methane hydrate were investigated during these processes. The results show that, during hydrate formation, the Raman peak (2 917 cm(-1)) of methane gas gradually splits into two peaks (2 905 and 2 915 cm(-1)) representing large and small cages, respectively, suggesting that the dissolved methane molecules go into two different chemical environments. In the meantime, the hydrogen bonds interaction is strengthened because water is changing from liquid to solid state gradually. As a result, the O-H stretching vibrations of water shift to lower wavenumber. During the decomposition process of methane hydrates, the Raman peaks of the methane molecules both in the large and small cages gradually clear up, and finally turn into a single peak of methane gas. The experimental results show that laser Raman spectroscopy can accurately demonstrate some relevant information of hydrate crystal structure changes during the formation and dissociation processes of methane hydrate.

  17. A comparison of ISCCP land surface temperature with other satellite and in situ observations

    NASA Astrophysics Data System (ADS)

    JiméNez, Carlos; Prigent, Catherine; Catherinot, Julie; Rossow, William; Liang, Pan; Moncet, Jean-Luc

    2012-04-01

    Land surface skin temperature (LST) estimates from the International Satellite Cloud Climatology Project (ISCCP) are compared with estimates from the satellite instruments AIRS and MODIS, and in situ observations from CEOP. ISCCP has generally slightly warmer nighttime LSTs compared with AIRS and MODIS (global) and CEOP (at specific sites). Differences are smaller than 2K, similar to other reported biases between satellite estimates. Larger differences are found in the day-time LSTs, especially for those regions where large LST values occur. Inspection of the AIRS and ISCCP brightness temperatures at the top of the atmosphere (TOA-BT) reveals that where the LSTs differ so too do the TOA-BT values. Area-averaged day-time TOA-BT values can differ as much as 5K in very dry regions. This could be related to differences in sensor calibration, but also to the large LST gradients at the AIRS mid-day overpass that likely amplify the impact of sensor mismatches. Part of the studied LST differences are also explained by discrepancies in the AIRS and ISCCP characterization of the surface (emissivity) and the atmosphere (water vapor). ISCCP calibration procedures are currently being revised to account better for sensor spectral response differences, and alternative atmospheric and surface data sets are being tested as part of a complete ISCCP reprocessing. This is expected to result in an improved ISCCP LST record.

  18. In situ atomic force microscopy observation of hydrogen absorption/desorption by Palladium thin film

    NASA Astrophysics Data System (ADS)

    Matsumoto, Itoko; Sakaki, Kouji; Nakamura, Yumiko; Akiba, Etsuo

    2011-12-01

    Grain structure changes in Pd thin film during hydrogen absorption and desorption were observed by in situ atomic force microscopy. The as-sputtered film had a smooth flat surface with 20-30 nm grains. Film that absorbed hydrogen showed buckling, caused by the compressive stress due to lattice expansion as Pd metal reacted with hydrogen to form the hydride. Grains on the buckles were agglomerated and deformed unlike those on flat areas beside the buckles. Film that absorbed and then desorbed hydrogen still showed some buckling; however, many buckles shrank and flattened when the compressive stress of lattice expansion was released during desorption. On both the remaining and the shrunken buckles, grain agglomeration was retained; whereas, the deformed grains reverted back to their original form. X-ray diffraction indicated compressive residual stress in the as-sputtered film and tensile residual stress in the film after hydrogen absorption/desorption. These results indicate that irreversible grain agglomeration is related to residual tensile stress in the film although agglomeration occurs only on the buckled areas.

  19. Constraints on CME Evolution from in situ Observations of Ionic Charge States

    NASA Technical Reports Server (NTRS)

    Gruesbeck, Jacob R.; Lepri, Susan T.; Zurbuchen, Thomas H.; Antiochos, Spiro K.

    2010-01-01

    We present a novel procedure for deriving the physical properties of Coronal Mass Ejections (CMES) in the corona. Our methodology uses in-situ measurements of ionic charge states of C, O, Si and Fe in the heliosphere and interprets them in the context of a model for the early evolution of ICME plasma, between 2 - 5 R-solar. We find that the data can be fit only by an evolution that consists of an initial heating of the plasma, followed by an expansion that ultimately results in cooling. The heating profile is consistent with a compression of coronal plasma due to flare reconnect ion jets and an expansion cooling due to the ejection, as expected from the standard CME/flare model. The observed frozen-in ionic charge states reflect this time-history and, therefore, provide important constraints for the heating and expansion time-scales, as well as the maximum temperature the CME plasma is heated to during its eruption. Furthermore, our analysis places severe limits on the possible density of CME plasma in the corona. We discuss the implications of our results for CME models and for future analysis of ICME plasma composition.

  20. In-situ observation of bubble formation at silicon melt-silica glass interface

    NASA Astrophysics Data System (ADS)

    Minami, Toshiro; Maeda, Susumu; Higasa, Mitsuo; Kashima, Kazuhiko

    2011-03-01

    The generation mechanism of pinhole defects in the Czochralski (CZ)-grown silicon (Si) single crystals was clarified by in-situ observations of bubble formation at the interface between Si melt and a silica glass crucible in a small experimental apparatus. The nucleation and growth of bubbles were facilitated by creating small cavities on the inner wall of the crucible. Si melting was conducted in an argon (Ar) atmosphere, and the pressure was maintained at either 100 Torr or close to a vacuum (no Ar-gas flow). It was found that in the presence of Ar, bubbles formed in the cavities immediately after the cavities came in contact with the melt. However, no bubbles formed in a vacuum in the experimental apparatus. These results indicate that the bubbles formed in the cavities are largely filled with Ar, and the initial bubble volumes are nearly comparable with those of the cavities. In an initial stage of expansion of a bubble, estimated volumes changed nearly in accordance with the Boyle-Charles law. Further, participation of SiO gas in bubble growth may explain the deviation of the bubble volume from the theoretical value anticipated if only Ar gas was involved in the bubble growth.

  1. In situ observation of water in a fuel cell catalyst using scanning electron microscopy.

    PubMed

    Ueda, Satoru; Kobayashi, Yoshio; Koizumi, Satoshi; Tsutsumi, Yasuyuki

    2015-04-01

    To visualize water in the catalyst of polymer electrolyte fuel cells (PEFCs), backscattered electron (BSE) imaging by means of scanning electron microscopy was employed. To confine a wet specimen of catalyst, an environmental wet cell was manufactured with a silicon nitride thin film (∼100 nm) as the beam window. By supplying humidified gas into the cell, a change in BSE brightness was detected in the catalyst attached to the silicon nitride window. As humidification proceeded, the BSE image became darker and returned brighter by switching to a dry gas. Monte Carlo simulations were performed to evaluate the energy and number of BSE obtained after passing through water with thickness d. Combining the results of the Monte Carlo simulation successfully converted the change in brightness to the change in thickness from d = 100 nm to d = 3 μm. This established method of evaluating water with a thickness resolution of the order of Δd = 100 nm can be applied to in situ observations of the catalyst in a PEFC during operation.

  2. In situ observation of fracture behavior of canine cortical bone under bending.

    PubMed

    Lin, Zilan X; Xu, Zhi-Hui; An, Yuehuei H; Li, Xiaodong

    2016-05-01

    Cortical bone provides many important body functions and maintains the rigidness and elasticity of bone. A common failure mode for bone structure is fracture under a bending force. In the current study, the fracture behavior of canine cortical bone under three-point bending was observed in situ using an atomic force microscope (AFM), a scanning electron microscope (SEM), and an optical microscope to examine the fracture process in detail. Nanoindentation was carried out to determine the elastic modulus and hardness of different building blocks of the canine cortical bone. The results have shown that the special structure of Haversian systems has significant effects on directing crack propagation. Although Haversian systems contain previously believed weak points, and micro-cracks initiate within Haversian systems, our findings have demonstrated that macro-cracks typically form around the boundaries of Haversian systems, i.e. the cement lines. Micro-cracks that developed inside Haversian systems have the functions of absorbing and dissipating energy and slow down on expanding when interstitial tissue cannot hold any more pressure, then plastic deformation and fracture occur.

  3. In situ observation of macroscopic phase separation in cobalt hexacyanoferrate film

    PubMed Central

    Takachi, Masamitsu; Moritomo, Yutaka

    2017-01-01

    Lithium-ion secondary batteries (LIBs) store electric energy via Li+ deintercalation from cathode materials. The Li+ deintercalation frequently drives a first-order phase transition of the cathode material as a result of the Li-ordering or Li-concentration effect and causes a phase separation (PS) into the Li-rich and Li-poor phases. Here, we performed an in situ microscopic investigation of the PS dynamics in thin films of cobalt hexacyanoferrate, LixCo[Fe(CN)6]0.9, against Li+ deintercalation. The thick film (d = 1.5 μm) shows a characteristic macroscopic PS of several tens of μm into the green (Li1.6Co[Fe(CN)6]0.9) and black (Li.6Co[Fe(CN)6]0.9) phases in the x range of 1.0 < x < 1.6. Reflecting the substrate strain, the thin film (d = 0.5 μm) shows no trace of the PS in the entire x region. Our observation suggests that the macroscopic PS plays a significant role in the charge/discharge dynamics of the cathode. PMID:28205619

  4. In Situ Observation of the Dislocation Structure Evolution During a Strain Path Change in Copper

    NASA Astrophysics Data System (ADS)

    Wejdemann, Christian; Poulsen, Henning Friis; Lienert, Ulrich; Pantleon, Wolfgang

    2013-01-01

    The evolution of deformation structures in individual grains embedded in polycrystalline copper specimens during strain path changes is observed in situ by high-resolution reciprocal space mapping with high-energy synchrotron radiation. A large number of individual subgrains is resolved; their behavior during the strain path change is revealed and complemented by the analysis of radial x-ray peak profiles for the entire grain. This allows distinction between two different regimes during the mechanically transient behavior following the strain path change: Below 0.3% strain, the number and orientation of the resolved subgrains change only slightly, while their elastic stresses are significantly altered. This indicates the existence of a microplastic regime during which only the subgrains deform plastically and no yielding of the dislocation walls occurs. After reloading above 0.3% strain, the elastic stresses of individual subgrains are about the same as in unidirectionally deformed reference specimens. They increase only slightly during further straining—accompanied by occasional emergence of new subgrains, abundant orientation changes, and disappearance of existing subgrains.

  5. In situ observation of shear-driven amorphization in silicon crystals

    NASA Astrophysics Data System (ADS)

    He, Yang; Zhong, Li; Fan, Feifei; Wang, Chongmin; Zhu, Ting; Mao, Scott X.

    2016-10-01

    Amorphous materials are used for both structural and functional applications. An amorphous solid usually forms under driven conditions such as melt quenching, irradiation, shock loading or severe mechanical deformation. Such extreme conditions impose significant challenges on the direct observation of the amorphization process. Various experimental techniques have been used to detect how the amorphous phases form, including synchrotron X-ray diffraction, transmission electron microscopy (TEM) and Raman spectroscopy, but a dynamic, atomistic characterization has remained elusive. Here, by using in situ high-resolution TEM (HRTEM), we show the dynamic amorphization process in silicon nanocrystals during mechanical straining on the atomic scale. We find that shear-driven amorphization occurs in a dominant shear band starting with the diamond-cubic (dc) to diamond-hexagonal (dh) phase transition and then proceeds by dislocation nucleation and accumulation in the newly formed dh-Si phase. This process leads to the formation of an amorphous Si (a-Si) band, embedded with dh-Si nanodomains. The amorphization of dc-Si via an intermediate dh-Si phase is a previously unknown pathway of solid-state amorphization.

  6. In-situ Observations of the Ionospheric F2-Region from the International Space Station

    NASA Technical Reports Server (NTRS)

    Coffey, Victoria N.; Wright, Kenneth H.; Minow, Joseph I.; Chandler, Michael O.; Parker, Linda N.

    2008-01-01

    The International Space Station orbit provides an ideal platform for in-situ studies of space weather effects on the mid and low latitude F-2 region ionosphere. The Floating Potential Measurement Unit (FPMU) operating on the ISS since Aug 2006, is a suite of plasma instruments: a Floating Potential Probe (FPP), a Plasma Impedance Probe (PIP), a Wide-sweep Langmuir Probe (WLP), and a Narrow-sweep Langmuir Probe (NLP). This instrument package provides a new opportunity for collaborative multi-instrument studies of the F-region ionosphere during both quiet and disturbed periods. This presentation first describes the operational parameters for each of the FPMU probes and shows examples of an intra-instrument validation. We then show comparisons with the plasma density and temperature measurements derived from the TIMED GUVI ultraviolet imager, the Millstone Hill ground based incoherent scatter radar, and DIAS digisondes, Finally we show one of several observations of night-time equatorial density holes demonstrating the capabilities of the probes for monitoring mid and low latitude plasma processes.

  7. In situ observation of macroscopic phase separation in cobalt hexacyanoferrate film

    NASA Astrophysics Data System (ADS)

    Takachi, Masamitsu; Moritomo, Yutaka

    2017-02-01

    Lithium-ion secondary batteries (LIBs) store electric energy via Li+ deintercalation from cathode materials. The Li+ deintercalation frequently drives a first-order phase transition of the cathode material as a result of the Li-ordering or Li-concentration effect and causes a phase separation (PS) into the Li-rich and Li-poor phases. Here, we performed an in situ microscopic investigation of the PS dynamics in thin films of cobalt hexacyanoferrate, LixCo[Fe(CN)6]0.9, against Li+ deintercalation. The thick film (d = 1.5 μm) shows a characteristic macroscopic PS of several tens of μm into the green (Li1.6Co[Fe(CN)6]0.9) and black (Li.6Co[Fe(CN)6]0.9) phases in the x range of 1.0 < x < 1.6. Reflecting the substrate strain, the thin film (d = 0.5 μm) shows no trace of the PS in the entire x region. Our observation suggests that the macroscopic PS plays a significant role in the charge/discharge dynamics of the cathode.

  8. Dynamic in situ observation of voltage-driven repeatable magnetization reversal at room temperature

    PubMed Central

    Gao, Ya; Hu, Jia-Mian; Nelson, C. T.; Yang, T. N.; Shen, Y.; Chen, L. Q.; Ramesh, R.; Nan, C. W.

    2016-01-01

    Purely voltage-driven, repeatable magnetization reversal provides a tantalizing potential for the development of spintronic devices with a minimum amount of power consumption. Substantial progress has been made in this subject especially on magnetic/ferroelectric heterostructures. Here, we report the in situ observation of such phenomenon in a NiFe thin film grown directly on a rhombohedral Pb(Mg1/3Nb2/3)0.7Ti0.3O3(PMN-PT) ferroelectric crystal. Under a cyclic voltage applied perpendicular to the PMN-PT without a magnetic field, the local magnetization of NiFe can be repetitively reversed through an out-of-plane excursion and then back into the plane. Using phase field simulations we interpret magnetization reversal as a synergistic effect of the metastable ferroelastic switching in the PMN-PT and an electrically rotatable local exchange bias field arising from the heterogeneously distributed NiO clusters at the interface. PMID:27029464

  9. Elasticity of MoS2 Sheets by Mechanical Deformation Observed by in Situ Electron Microscopy

    PubMed Central

    2015-01-01

    MoS2 has been the focus of extensive research due to its potential applications. More recently, the mechanical properties of MoS2 layers have raised interest due to applications in flexible electronics. In this article, we show in situ transmission electron microcsopy (TEM) observation of the mechanical response of a few layers of MoS2 to an external load. We used a scanning tunneling microscope (STM) tip mounted on a TEM stage to induce deformation on nanosheets of MoS2 containing few layers. The results confirm the outstanding mechanical properties on the MoS2. The layers can be bent close to 180°. However, when the tip is retrieved the initial structure is recovered. Evidence indicates that there is a significant bond reconstruction during the bending with an outstanding capability to recover the initial bond structure. The results show that flexibility of three layers of MoS2 remains the same as a single layer while increasing the bending modulus by 3 orders of magnitude. Our findings are consistent with theoretical calculations and confirm the great potential of MoS2 for applications. PMID:25598860

  10. NASA DC-8 Airborne Scanning Lidar Cloud and Contrail Observations

    NASA Technical Reports Server (NTRS)

    Uthe, Edward E.; Oseberg, Terje E.; Nielsen, Norman B.

    1997-01-01

    An angular scanning backscatter lidar has been developed and operated from the NASA DC-8 aircraft; the lidar viewing direction could be scanned from vertically upward to forward in the direction of aircraft travel to vertically downward. The scanning lidar was used to generate real-time video displays of clouds and contrails above, below, and ahead of the aircraft to aid in positioning the aircraft for achieving optimum cloud/contrail sampling by onboard in situ samplers. Data examples show that the lidar provides unique information for the interpretation of the other data records and that combined data analyses provides enhanced evaluations of contrail/cloud structure, dynamics, composition, and optical/radiative properties.

  11. Using red light for in situ observations of deep-sea fishes

    NASA Astrophysics Data System (ADS)

    Widder, E. A.; Robison, B. H.; Reisenbichler, K. R.; Haddock, S. H. D.

    2005-11-01

    Observations of animals in the deep ocean typically require the use of bright lights that can damage eyes and disrupt normal behaviors. Although the use of infrared light is an effective means of unobtrusive observation on land, it is far less effective in the ocean where long wavelength light is rapidly attenuated by seawater. Here we describe in situ observations of the behavior of the sablefish, Anoplopoma fimbria, around a baited site under different lighting conditions. Fish were observed with low-light-level imaging that had adequate sensitivity to compensate for the attenuation losses associated with the use of long wavelength light in water. ROV-based experiments compared the number of sablefish seen around bait, illuminated alternately with red vs. white light. Significantly more fish were seen under red light than white light with the average number of sablefish observed per 10 min viewing interval under red light being 38.9 (±18.5 SD) compared to 7.5 (±7.1 SD) under white light. Under both red and white light sablefish spent only brief periods in the illumination field (10.5 s [±8.7 SD] under red light and 6.6 s [±8.7 SD] under white light). It appeared that sablefish were responding to competing drives of attraction to the bait and avoidance of the lights and that the avoidance was greater for white light than for red light. Observations were also made with the newly developed deep-sea observatory, Eye-in-the-Sea, using long wavelength LED illumination. The onset of LED illumination did not generally produce a startle response from fish around the bait, and in some cases invoked no response at all. However, in the majority of cases the fish moved out of the circle of red-light illumination during the 7.5 s recording period, indicating that the light was detectable and aversive to these fish. This was true with both 660 and 680 nm LED illuminators. We conclude that while a sharper short-wavelength cutoff of the illumination source is required to

  12. New Platforms for Suborbital Astronomical Observations and In Situ Atmospheric Measurements: Spacecraft, Instruments, and Facilities

    NASA Astrophysics Data System (ADS)

    Rodway, K.; DeForest, C. E.; Diller, J.; Vilas, F.; Sollitt, L. S.; Reyes, M. F.; Filo, A. S.; Anderson, E.

    2014-12-01

    Suborbital astronomical observations have over 50 years' history using NASA's sounding rockets and experimental space planes. The new commercial space industry is developing suborbital reusable launch vehicles (sRLV's) to provide low-cost, flexible, and frequent access to space at ~100 km altitude. In the case of XCOR Aerospace's Lynx spacecraft, the vehicle design and capabilities work well for hosting specially designed experiments that can be flown with a human-tended researcher or alone with the pilot on a customized mission. Some of the first-generation instruments and facilities that will conduct solar observations on dedicated Lynx science missions include the SwRI Solar Instrument Pointing Platform (SSIPP) and Atsa Suborbital Observatory, as well as KickSat sprites, which are picosatellites for in situ atmospheric and solar phenomena measurements. The SSIPP is a demonstration two-stage pointed solar observatory that operates inside the Lynx cockpit. The coarse pointing stage includes the pilot in the feedback loop, and the fine stage stabilizes the solar image to achieve arcsecond class pointing. SSIPP is a stepping-stone to future external instruments that can operate with larger apertures and shorter wavelengths in the solar atmosphere. The Planetary Science Institute's Atsa Suborbital Observatory combines the strengths of ground-based observatories and space-based observing to create a facility where a telescope is maintained and used interchangeably with either in-house facility instruments or user-provided instruments. The Atsa prototype is a proof of concept, hand-guided camera that mounts on the interior of the Lynx cockpit to test target acquisition and tracking for human-operated suborbital astronomy. KickSat sprites are mass-producible, one inch printed circuit boards (PCBs) populated by programmable off the shelf microprocessors and radios for real time data transmission. The sprite PCBs can integrate chip-based radiometers, magnetometers

  13. Transmission Electron Microscope In Situ Straining Technique to Directly Observe Defects and Interfaces During Deformation in Magnesium

    SciTech Connect

    Morrow, Benjamin M.; Cerreta, E. K.; McCabe, R. J.; Tomé, C. N.

    2015-05-14

    In-situ straining was used to study deformation behavior of hexagonal close-packed (hcp) metals.Twinning and dislocation motion, both essential to plasticity in hcp materials, were observed.Typically, these processes are characterized post-mortem by examining remnant microstructural features after straining has occurred. By imposing deformation during imaging, direct observation of active deformation mechanisms is possible. This work focuses on straining of structural metals in a transmission electron microscope (TEM), and a recently developed technique that utilizes familiar procedures and equipment to increase ease of experiments. In-situ straining in a TEM presents several advantages over conventional post-mortem characterization, most notably time-resolution of deformation and streamlined identification of active deformation mechanisms. Drawbacks to the technique and applicability to other studies are also addressed. In-situ straining is used to study twin boundary motion in hcp magnesium. A {101¯2} twin was observed during tensile and compressive loading. Twin-dislocation interactions are directly observed. Notably, dislocations are observed to remain mobile, even after multiple interactions with twin boundaries, a result which suggests that Basinki’s dislocation transformation mechanism by twinning is not present in hcp metals. The coupling of in-situ straining with traditional post-mortem characterization yields more detailed information about material behavior during deformation than either technique alone.

  14. Comparison of Multiple Satellite Soil Moisture Products Using In-Situ Soil Moisture Observations Over the Continental United States

    NASA Astrophysics Data System (ADS)

    Chavez, N.; Galvan, J., III; McRoberts, D. B.; Quiring, S. M.; Ford, T.

    2015-12-01

    We evaluate the skill of multiple satellite-derived soil moisture products using in-situ soil moisture observations from over 50 long-record stations in the continental United States. The satellite products compared include AMSR-E, ASCAT, SMOS, TMI, ESA CCI, and SMAP. Daily volumetric water content and percentiles of volumetric water content from each satellite product is compared with the observations from the corresponding station. We evaluate the similarity between the satellite and in-situ products with regard to the climate and biome conditions of the area as well as the representativeness of the in-situ station for the satellite footprint. We find moderate-to-strong correspondence between all satellite products and in-situ soil moisture observations. Differences between the satellite and observation datasets are attributed to varying land cover conditions, snow cover, and the spatial mismatch of the point observation with the satellite product grid cell. In general, our results suggest that the satellite products evaluated can accurately capture temporal variability of soil moisture near the surface, but do show systematic offsets at several stations across the study region.

  15. Transmission Electron Microscope In Situ Straining Technique to Directly Observe Defects and Interfaces During Deformation in Magnesium

    DOE PAGES

    Morrow, Benjamin M.; Cerreta, E. K.; McCabe, R. J.; ...

    2015-05-14

    In-situ straining was used to study deformation behavior of hexagonal close-packed (hcp) metals.Twinning and dislocation motion, both essential to plasticity in hcp materials, were observed.Typically, these processes are characterized post-mortem by examining remnant microstructural features after straining has occurred. By imposing deformation during imaging, direct observation of active deformation mechanisms is possible. This work focuses on straining of structural metals in a transmission electron microscope (TEM), and a recently developed technique that utilizes familiar procedures and equipment to increase ease of experiments. In-situ straining in a TEM presents several advantages over conventional post-mortem characterization, most notably time-resolution of deformation andmore » streamlined identification of active deformation mechanisms. Drawbacks to the technique and applicability to other studies are also addressed. In-situ straining is used to study twin boundary motion in hcp magnesium. A {101¯2} twin was observed during tensile and compressive loading. Twin-dislocation interactions are directly observed. Notably, dislocations are observed to remain mobile, even after multiple interactions with twin boundaries, a result which suggests that Basinki’s dislocation transformation mechanism by twinning is not present in hcp metals. The coupling of in-situ straining with traditional post-mortem characterization yields more detailed information about material behavior during deformation than either technique alone.« less

  16. Hydrographic properties of separate residual basins of the Aral Sea: in situ observations and intercomparison

    NASA Astrophysics Data System (ADS)

    Izhitskiy, Alexander; Zavialov, Peter; Kurbaniyazov, Abilgazi

    2015-04-01

    Desiccation of the Aral Sea continued intensively throughout the last decade. As reported by NASA and widely commented in mass media, the eastern lobe of the Southern Sea (i.e., the Large Aral Sea) dried up completely in the summer of 2014. Only the western basin of the Large Sea remains there, and the separation of its northernmost portion called Chernyshev Bay is imminent. The northern part of the former Aral Sea known as the Small Aral Sea has separated decades ago and eventually stabilized thanks to a man-made dam trapping all of the Syr Daria discharges in the Small Sea. In addition, the Tschebas Bay, formerly a large bay of the Aral Sea, has evolved into a separate lake with relatively stable boundaries. In this way, the present-day Aral Sea should be considered as a system of separated water bodies with a common origin but different fates and very different physical, chemical, and biological features. In the presented study, we focus on hydrophysical state of the newly individual parts of the former Aral Sea. The comparative investigation is based on field data collected during two surveys of Shirshov Institute of Oceanology to the Aral Sea which took place in the fall season of 2014. In situ measurements including CTD profiling and water sampling were carried in the central western basin of the Large Aral (Aktumsuk area), in the northern extremity of the western Large Aral (Chernyshev bay), in Tschebas Lake, and the western part of the Small Sea (Shevchenko Bay). The analysis of direct observations together with the satellite data allows clarifying main processes and factors determining the physical state of the residual water bodies. According to the results of the in situ observations, three different types of hydrographic structure were documented in the lakes of the former Aral Sea. Salinity of Tschebas Lake water was around 92 g/kg, with the water column fully mixed from surface to bottom. The CTD measurements conducted in the Shevchenko bay of the

  17. Diagnostics of the Tropical Tropopause Layer from in-situ observations and CCM data

    NASA Astrophysics Data System (ADS)

    Palazzi, E.; Fierli, F.; Cairo, F.; Cagnazzo, C.; di Donfrancesco, G.; Manzini, E.; Ravegnani, F.; Schiller, C.; D'Amato, F.; Volk, C. M.

    2009-12-01

    A suite of diagnostics is applied to in-situ aircraft measurements and one Chemistry-Climate Model (CCM) data to characterize the vertical structure of the Tropical Tropopause Layer (TTL). The diagnostics are based on vertical tracer profiles and relative vertical tracer gradients, using tropopause-referenced coordinates, and tracer-tracer relationships in the tropical Upper Troposphere/Lower Stratosphere (UT/LS). Observations were obtained during four tropical campaigns performed from 1999 to 2006 with the research aircraft Geophysica and have been compared to the output of the ECHAM5/MESSy CCM. The model vertical resolution in the TTL (~500 m) allows for appropriate comparison with high-resolution aircraft observations and the diagnostics used highlight common TTL features between the model and the observational data. The analysis of the vertical profiles of water vapour, ozone, and nitrous oxide, in both the observations and the model, shows that concentration mixing ratios exhibit a strong gradient change across the tropical tropopause, due to the role of this latter as a transport barrier and that transition between the tropospheric and stratospheric regimes occurs within a finite layer. The use of relative vertical ozone and carbon monoxide gradients, in addition to the vertical profiles, helps to highlight the region where this transition occurs and allows to give an estimate of its thickness. The analysis of the CO-O3 and H2O-O3 scatter plots and of the Probability Distribution Function (PDF) of the H2O-O3 pair completes this picture as it allows to better distinguish tropospheric and stratospheric regimes that can be identified by their different chemical composition. The joint analysis and comparison of observed and modelled data allows to state that the model can represent the background TTL structure and its seasonal variability rather accurately. The model estimate of the thickness of the interface region between tropospheric and stratospheric regimes

  18. Estimating global groundwater withdrawal and depletion using an integrated hydrological model, GRACE, and in situ observations

    NASA Astrophysics Data System (ADS)

    Pokhrel, Y. N.; Koirala, S.; Hanasaki, N.; Yeh, P. J.; Kanae, S.; Oki, T.

    2012-12-01

    In the past several decades extensive use of groundwater, particularly for irrigation, has led to rapid groundwater depletion in many regions. This has not only affected the terrestrial water cycle but also resulted in global sea level rise because a large portion of unsustainably pumped groundwater eventually ends up in the ocean. Therefore, monitoring groundwater resources and their use has become increasingly important. While in situ observations are invaluable for assessing and monitoring groundwater availability, global models and satellite-based observations provide further insights into groundwater dynamics in regions where observations are scarce. In this study, we highlight the major hotspots of global groundwater depletion and the consequent sea level change by using an integrated modeling framework. The model was developed by incorporating a dynamic groundwater scheme and a pumping scheme into a global land surface model (MATSIRO: Minimal Advanced Treatments of Surface Interaction and Runoff) which also accounts for the effects of major human activities (e.g., reservoir operation, irrigation, and water withdrawal) on the terrestrial water cycle. All components of the model are fully coupled and the model tracks the flow of water taking into account the withdrawals of water for agricultural, domestic, and industrial uses from various sources such as river networks, medium-sized reservoirs, and groundwater reservoir. Using model results, GRACE measurement, and ground-based observations by the United States Geological Survey, we demonstrate that groundwater has been declining in many regions with a particular focus on the major aquifers in the United States. In the region overlying the High Plains aquifer, which is extensively irrigated mainly by using groundwater, the simulated groundwater withdrawal of ~23 km3/yr agrees well with the observational record of ~24 km3/yr for circa 2000. Moreover, corresponding closely with the USGS water level observations

  19. Curiosity in Situ Observations at Kylie, a Preview of the Kimberley Drill Site Geology

    NASA Astrophysics Data System (ADS)

    Edgar, L. A.; Williams, R. M. E.; Rice, M. S.; Stack, K.; Grotzinger, J. P.; Gupta, S.; Rubin, D. M.; Sumner, D. Y.; Lewis, K. W.; Le Deit, L.; Wiens, R. C.

    2014-12-01

    After passing through Dingo Gap, Curiosity turned south and explored the Kylie outcrop on sols 550 to 555. Kylie is topographically higher (by ~10 meters) than the Kimberley located ~300 m to the south, and shares the same succession of geomorphic units identified in satellite images. Thus, in situ observations at Kylie provided context for the subsequent drilling campaign at the Kimberley. Additionally, comparisons of the stratigraphy exposed at Kylie with stratigraphic sections observed at other locations along the traverse (including Darwin, Cooperstown, and Dingo Gap) enable regional correlations and the development of working hypotheses for the former depositional environments. The sedimentary facies exposed at Kylie include pebble-rich conglomerates and sandstones that vary in bedding orientation and stratification. Exposed on the basin walls is a fining upward stratigraphic succession with a basal pebble conglomerate, flat-bedded sandstone, and a resistant, dark-grey massive to crudely stratified sandstone capping facies. The conglomerate facies forms a prominent bench that rims the western side of the basin. ChemCam data indicate that the pebble-rich conglomerates have mafic and felsic elements and appear similar in composition to the conglomerates previously encountered during the mission. Within the basin, the sedimentary deposits appear to drape pre-existing topography. The most voluminous facies has decimeter-thick south-dipping beds of cross-bedded sandstone that correspond to distinct NE-SW trending linear bands in orbital images. In the southern portion of the basin, these south-dipping cross-bedded sandstones are overlain by thin-bedded, sub-meter cross-bedded sandstone and a poorly exposed, scree-covered butte forming facies. The Kylie deposits are consistent with a complex scenario of dominantly fluvial activity, although the nature and magnitude of flows is still being investigated.

  20. Internal waves in the Black Sea: satellite observations and in-situ measurements

    NASA Astrophysics Data System (ADS)

    Lavrova, Olga Yu.; Mityagina, Marina I.; Serebryany, Andrey N.; Sabinin, Konstantin D.; Kalashnikova, Nina A.; Krayushkin, Evgeny V.; Khymchenko, Ielizaveta

    2014-10-01

    Satellite radar (SAR) and visible band data from Envisat ASAR, ERS-2 SAR, Lansat-5,7,8 sensors were used to investigate internal waves (IWs) in the Black Sea. The three main areas of the Black Sea where surface manifestations of internal waves (SMIWs) were mostly observed are: the Danube Delta, Crimea Peninsula and the northeastern region near Novorossiysk. The main goal of our investigation was to define the mechanisms of IW generation in the non-tidal sea. In the first area, IWs are observed rather often due to surface intrusions of fresh waters of the Danube River. In contrast to usual soliton-like IW trains caused by river plumes, soliton trains near the Danuba Delta propagate in different directions and often subject to nonlinear interactions. The interrelation between location and orientation of IW trains and fresh water fronts is discussed. In the area off Crimea, in our opinion, IWs are generated mainly by upwelling relaxation and interaction between internal inertial waves and bottom topography features. SMIW in the northeastern part of the Black Sea are scarce, though IWs are regularly revealed by in-situ measurements. Field measurements were conducted in the northeastern part of the Black Sea from a small boat and from scientific sea platform near Crimea employing CTD probes, thermistor chain and Acoustic Doppler Current Profilers (ADCP). ADCP measurements allowed us to detect a number of IW trains. Their amplitudes were estimated to reach 5-8 m. Joint analysis of satellite SAR and subsatellite data gave an assessment of their typical wavelength at 90-100 m.

  1. In situ observation and analysis of ultrasonic capillary effect in molten aluminium.

    PubMed

    Tzanakis, I; Xu, W W; Eskin, D G; Lee, P D; Kotsovinos, N

    2015-11-01

    An in situ synchrotron radiographic study of a molten Al-10 wt% Cu alloy under the influence of an external ultrasonic field was carried out using the Diamond-Manchester Branchline pink X-ray imaging at the Diamond Light Source in UK. A bespoke test rig was used, consisting of an acoustic transducer with a titanium sonotrode coupled with a PID-controlled resistance furnace. An ultrasonic frequency of 30 kHz, with a peak to peak amplitude at 140 microns, was used, producing a pressure output of 16.9 MPa at the radiation surface of the 1-mm diameter sonotrode. This allowed quantification of not only the cavitation bubble formation and collapse, but there was also evidence of the previously hypothesised ultrasonic capillary effect (UCE), providing the first direct observations of this phenomenon in a molten metallic alloy. This was achieved by quantifying the re-filling of a pre-existing groove in the shape of a tube (which acted as a micro-capillary channel) formed by the oxide envelope of the liquid sample. Analytical solutions of the flow suggest that the filling process, which took place in very small timescales, was related to micro-jetting from the collapsing cavitation bubbles. In addition, a secondary mechanism of liquid penetration through the groove, which is related with the density distribution of the oxides inside the groove, and practically to the filtration of aluminium melt from oxides, was revealed. The observation of the almost instantaneous re-filling of a micro-capillary channel with the metallic melt supports the hypothesised sono-capillary effect in technologically important liquids other than water, like metallic alloys with substantially higher surface tension and density.

  2. In Situ Observations during Chemical Vapor Deposition of Hexagonal Boron Nitride on Polycrystalline Copper

    PubMed Central

    2014-01-01

    Using a combination of complementary in situ X-ray photoelectron spectroscopy and X-ray diffraction, we study the fundamental mechanisms underlying the chemical vapor deposition (CVD) of hexagonal boron nitride (h-BN) on polycrystalline Cu. The nucleation and growth of h-BN layers is found to occur isothermally, i.e., at constant elevated temperature, on the Cu surface during exposure to borazine. A Cu lattice expansion during borazine exposure and B precipitation from Cu upon cooling highlight that B is incorporated into the Cu bulk, i.e., that growth is not just surface-mediated. On this basis we suggest that B is taken up in the Cu catalyst while N is not (by relative amounts), indicating element-specific feeding mechanisms including the bulk of the catalyst. We further show that oxygen intercalation readily occurs under as-grown h-BN during ambient air exposure, as is common in further processing, and that this negatively affects the stability of h-BN on the catalyst. For extended air exposure Cu oxidation is observed, and upon re-heating in vacuum an oxygen-mediated disintegration of the h-BN film via volatile boron oxides occurs. Importantly, this disintegration is catalyst mediated, i.e., occurs at the catalyst/h-BN interface and depends on the level of oxygen fed to this interface. In turn, however, deliberate feeding of oxygen during h-BN deposition can positively affect control over film morphology. We discuss the implications of these observations in the context of corrosion protection and relate them to challenges in process integration and heterostructure CVD. PMID:25673919

  3. Quantifying spatial and temporal variability in atmospheric ammonia with in situ and space-based observations--article

    EPA Science Inventory

    Ammonia plays an important role in many biogeochemical processes, yet atmospheric mixing ratios are not well known. Recently, methods have been developed for retrieving NH3 from space-based observations, but they have not been compared to in situ measurements. We have conducted a...

  4. The development and evaluation of airborne in situ N2O and CH4 sampling using a Quantum Cascade Laser Absorption Spectrometer (QCLAS)

    NASA Astrophysics Data System (ADS)

    Pitt, J. R.; Le Breton, M.; Allen, G.; Percival, C. J.; Gallagher, M. W.; Bauguitte, S. J.-B.; O'Shea, S. J.; Muller, J. B. A.; Zahniser, M. S.; Pyle, J.; Palmer, P. I.

    2015-08-01

    Spectroscopic measurements of atmospheric N2O and CH4 mole fractions were made on board the FAAM (Facility for Airborne Atmospheric Measurements) large Atmospheric Research Aircraft. We present details of the mid-IR Aerodyne Research Inc. Quantum Cascade Laser Absorption Spectrometer (QCLAS) employed, including its configuration for airborne sampling, and evaluate its performance over 17 flights conducted during summer 2014. Two different methods of correcting for the influence of water vapour on the spectroscopic retrievals are compared and evaluated. A new in-flight calibration procedure to account for the observed sensitivity of the instrument to ambient pressure changes is described, and its impact on instrument performance is assessed. Test flight data linking this sensitivity to changes in cabin pressure is presented. Total 1σ uncertainties of 1.81 ppb for CH4 and 0.35 ppb for N2O are derived. We report a mean difference in 1 Hz CH4 mole fraction of 2.05 ppb (1σ = 5.85 ppb) between in-flight measurements made using the QCLAS and simultaneous measurements using a previously characterised Los Gatos Research Fast Greenhouse Gas Analyser (FGGA). Finally, a potential case study for the estimation of a regional N2O flux using a mass balance technique is identified, and the method for calculating such an estimate is outlined.

  5. The development and evaluation of airborne in situ N2O and CH4 sampling using a quantum cascade laser absorption spectrometer (QCLAS)

    NASA Astrophysics Data System (ADS)

    Pitt, J. R.; Le Breton, M.; Allen, G.; Percival, C. J.; Gallagher, M. W.; Bauguitte, S. J.-B.; O'Shea, S. J.; Muller, J. B. A.; Zahniser, M. S.; Pyle, J.; Palmer, P. I.

    2016-01-01

    Spectroscopic measurements of atmospheric N2O and CH4 mole fractions were made on board the FAAM (Facility for Airborne Atmospheric Measurements) large atmospheric research aircraft. We present details of the mid-infrared quantum cascade laser absorption spectrometer (QCLAS, Aerodyne Research Inc., USA) employed, including its configuration for airborne sampling, and evaluate its performance over 17 flights conducted during summer 2014. Two different methods of correcting for the influence of water vapour on the spectroscopic retrievals are compared and evaluated. A new in-flight calibration procedure to account for the observed sensitivity of the instrument to ambient pressure changes is described, and its impact on instrument performance is assessed. Test flight data linking this sensitivity to changes in cabin pressure are presented. Total 1σ uncertainties of 2.47 ppb for CH4 and 0.54 ppb for N2O are derived. We report a mean difference in 1 Hz CH4 mole fraction of 2.05 ppb (1σ = 5.85 ppb) between in-flight measurements made using the QCLAS and simultaneous measurements using a previously characterised Fast Greenhouse Gas Analyser (FGGA, Los Gatos Research, USA). Finally, a potential case study for the estimation of a regional N2O flux using a mass balance technique is identified, and the method for calculating such an estimate is outlined.

  6. Observing lake ice phenology across Alaska using in situ sensors, aircraft, and satellites

    NASA Astrophysics Data System (ADS)

    Arp, C. D.; Jones, B. M.; Grosse, G.; Bodony, K.; Sturdivant, E.; Frey, K. E.

    2013-12-01

    The timing of ice-out in high latitudes is a fundamental threshold for lake ecosystems and an indicator of climate change. Thus, there is a need to understand lake ice phenology at multiple scales from small to large lakes and across lake-rich landscapes. In this study, we observed ice-out timing for large lakes using MODIS imagery in eleven lake districts across Alaska from 2007 - 2012 and validated these and expanded to smaller lakes using in situ sensors and shore-based cameras. Over this six year period, the mean lake ice-out for all lakes was 27 May and ranged from 07 May in Kenai to 06 July in Arctic Coastal Plain lake districts with relatively low interannual variability. Approximately 80% of the variation in ice out timing was explained by the 0°C air temperature isotherm date (ATID) and lake area. Shoreline irregularity, watershed area, and river connectivity explained additional variation in some districts. Inter-district analysis of coherence showed synchronous ice-out patterns with the exception of the two arctic coastal districts where ice-out occurs later (June - July) and regional climatology is strongly sea-ice influenced. Following this baseline analysis to document spatial and temporal variability, Alaska experienced record cold spring conditions in 2013. This apparent anomaly from long-term trends of earlier springs in northern latitudes provided an opportunity to validate empirical models and look at lake responses under conditions more representative of times before modern warming. In 2013 mean ice-out for all study lakes was 13 days later than mean for the previous six year observation period. The lower latitude and interior lake districts Denali, Kenai, and Minto Flats had ice-free conditions >18 days later in 2013 than the baseline period compared to higher latitude and coastal districts Beringia, Yukon-Kuskokwim Delta, and Arctic Coastal Plain became ice-free well within the range of recent interannual variability. Observations from this

  7. Airborne DIAL Ozone and Aerosol Trends Observed at High Latitudes Over North America from February to May 2000

    NASA Technical Reports Server (NTRS)

    Hair, Jonathan W.; Browell, Edward V.; Butler, Carolyn F.; Grant, William B.; DeYoung, Russell J.; Fenn, Marta A.; Brackett, Vince G.; Clayton, Marian B.; Brasseur, Lorraine

    2002-01-01

    Ozone (O3) and aerosol scattering ratio profiles were obtained from airborne lidar measurements on thirty-eight aircraft flights over seven aircraft deployments covering the latitudes of 40 deg.-85 deg.N between 4 February and 23 May 2000 as part of the TOPSE (Tropospheric Ozone Production about the Spring Equinox) field experiment. The remote and in situ O3 measurements were used together to produce a vertically-continuous O3 profile from near the surface to above the tropopause. Ozone, aerosol, and potential vorticity (PV) distributions were used together to identify the presence of pollution plumes and stratospheric intrusions. The number of observed pollution plumes was found to increase into the spring along with a significant increase in aerosol loading. Ozone was found to increase in the middle free troposphere (4-6 km) at high latitudes (60 deg.-85 deg. N) by an average of 4.3 ppbv/mo from about 55 ppbv in early February to over 72 ppbv in mid-May. The average aerosol scattering ratios in the same region increased at an average rate of 0.37/mo from about 0.35 to over 1.7. Ozone and aerosol scattering were highly correlated over entire field experiment. Based on the above results and the observed aircraft in-situ measurements, it was estimated that stratospherically-derived O3 accounted for less than 20% of the observed increase in mid tropospheric O3 at high latitudes. The primary cause of the observed O3 increase was found to be the photochemical production of O3 in pollution plumes.

  8. Methane emissions from Alaska in 2012 from CARVE airborne observations.

    PubMed

    Chang, Rachel Y-W; Miller, Charles E; Dinardo, Steven J; Karion, Anna; Sweeney, Colm; Daube, Bruce C; Henderson, John M; Mountain, Marikate E; Eluszkiewicz, Janusz; Miller, John B; Bruhwiler, Lori M P; Wofsy, Steven C

    2014-11-25

    We determined methane (CH4) emissions from Alaska using airborne measurements from the Carbon Arctic Reservoirs Vulnerability Experiment (CARVE). Atmospheric sampling was conducted between May and September 2012 and analyzed using a customized version of the polar weather research and forecast model linked to a Lagrangian particle dispersion model (stochastic time-inverted Lagrangian transport model). We estimated growing season CH4 fluxes of 8 ± 2 mg CH4⋅m(-2)⋅d(-1) averaged over all of Alaska, corresponding to fluxes from wetlands of 56(-13)(+22) mg CH4⋅m(-2)⋅d(-1) if we assumed that wetlands are the only source from the land surface (all uncertainties are 95% confidence intervals from a bootstrapping analysis). Fluxes roughly doubled from May to July, then decreased gradually in August and September. Integrated emissions totaled 2.1 ± 0.5 Tg CH4 for Alaska from May to September 2012, close to the average (2.3; a range of 0.7 to 6 Tg CH4) predicted by various land surface models and inversion analyses for the growing season. Methane emissions from boreal Alaska were larger than from the North Slope; the monthly regional flux estimates showed no evidence of enhanced emissions during early spring or late fall, although these bursts may be more localized in time and space than can be detected by our analysis. These results provide an important baseline to which future studies can be compared.

  9. Methane emissions from Alaska in 2012 from CARVE airborne observations

    PubMed Central

    Chang, Rachel Y.-W.; Miller, Charles E.; Dinardo, Steven J.; Karion, Anna; Sweeney, Colm; Daube, Bruce C.; Henderson, John M.; Mountain, Marikate E.; Eluszkiewicz, Janusz; Miller, John B.; Bruhwiler, Lori M. P.; Wofsy, Steven C.

    2014-01-01

    We determined methane (CH4) emissions from Alaska using airborne measurements from the Carbon Arctic Reservoirs Vulnerability Experiment (CARVE). Atmospheric sampling was conducted between May and September 2012 and analyzed using a customized version of the polar weather research and forecast model linked to a Lagrangian particle dispersion model (stochastic time-inverted Lagrangian transport model). We estimated growing season CH4 fluxes of 8 ± 2 mg CH4⋅m−2⋅d−1 averaged over all of Alaska, corresponding to fluxes from wetlands of 56−13+22 mg CH4⋅m−2⋅d−1 if we assumed that wetlands are the only source from the land surface (all uncertainties are 95% confidence intervals from a bootstrapping analysis). Fluxes roughly doubled from May to July, then decreased gradually in August and September. Integrated emissions totaled 2.1 ± 0.5 Tg CH4 for Alaska from May to September 2012, close to the average (2.3; a range of 0.7 to 6 Tg CH4) predicted by various land surface models and inversion analyses for the growing season. Methane emissions from boreal Alaska were larger than from the North Slope; the monthly regional flux estimates showed no evidence of enhanced emissions during early spring or late fall, although these bursts may be more localized in time and space than can be detected by our analysis. These results provide an important baseline to which future studies can be compared. PMID:25385648

  10. Retrieval of Atmospheric Temperature from Airborne Microwave Radiometer Observations

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Schreier, Franz; Kenntner, Mareike; Fix, Andreas; Trautmann, Thomas

    2015-11-01

    Atmospheric temperature is a key geophysical parameter associated with fields such as meteorology, climatology, or photochemistry. There exist several techniques to measure temperature profiles. In the case of microwave remote sensing, the vertical temperature profile can be estimated from thermal emission lines of molecular oxygen. The MTP (Microwave Temperature Profiler) instrument is an airborne radiometer developed at the Jet Propulsion Laboratory (JPL), United States. The instrument passively measures natural thermal emission from oxygen lines at 3 frequencies and at a selection of 10 viewing angles (from near zenith to near nadir). MTP has participated in hundreds of flights, including on DLR's Falcon and HALO aircrafts. These flights have provided data of the vertical temperature distribution from the troposphere to the lower stratosphere with a good temporal and spatial resolution. In this work, we present temperature retrievals based on the Tikhonov-type regularized nonlinear least squares fitting method. In particular, Jacobians (i.e. temperature derivatives) are evaluated by means of automatic differentiation. The retrieval performance from the MTP measurements is analyzed by using synthetic data. Besides, the vertical sensitivity of the temperature retrieval is studied by weighting functions characterizing the sensitivity of the transmission at different frequencies with respect to changes of altitude levels.

  11. First joint in situ and global observations of the medium-energy oxygen and hydrogen in the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Valek, P. W.; Goldstein, J.; Jahn, J.-M.; McComas, D. J.; Spence, H. E.

    2015-09-01

    We present the first simultaneous observations of the in situ ions and global Energetic Neutral Atom (ENA) images of the composition-separated, medium-energy (~1-50 keV) particle populations of the inner magnetosphere. The ENA emissions are mapped into L shell/magnetic local time space based on the exospheric density along the line of sight (LOS). The ENA measurement can then be scaled to determine an average ion flux along a given LOS. The in situ ion flux tends to be larger than the scaled ENAs at the same local time. This indicates that the ion population is more concentrated in the Van Allen Probes orbital plane than distributed along the Two Wide-angle Imaging Neutral-atom Spectrometers LOS. For the large storm of 14 November 2012, we observe that the concentration of O (in situ ions and ENAs) increases during the storm's main phase with a relatively larger increase than H. The ratio of the O+/H+ can be measured both from the in situ observations and from the ENA images. During the main phase, this O+/H+ increase is initially seen near midnight, but when the storm reaches its peak value the O+/H+ ratio increases across all local times, with the largest at dusk and dawn.

  12. VISIONS: Combined remote sensing and in situ observations of auroral zone ion outflow during a substorm

    NASA Astrophysics Data System (ADS)

    Rowland, D. E.; Clemmons, J. H.; Hecht, J. H.; Lemon, C. L.; Collier, M. R.; Keller, J. W.; Pfaff, R. F.; Klenzing, J.; McLain, J.

    2013-12-01

    The 'first step' in the chain of events that energizes thermal ions from a few tenths of an eV to 10 keV and transports them from the topside ionosphere to high altitudes occurs in the 300-1000 km altitude regime. In this region, various drivers work together to heat and accelerate the ions and push them up the field line. These include Joule heating, soft electron precipitation (driving ambipolar fields), and BBELF and VLF waves. Since the ions need to gain at least several eV to reach the higher altitudes where wave-particle interactions have been observed to form ion conics and beams, the low-altitude region serves as a 'rate limiting step' for the overall process of ion energization and outflow. Major outstanding questions still remain as to the extent and duration of outflow, and the details of the mechanisms that drive it - questions that can only be resolved by studying this critical altitude region. VISIONS (VISualizing Ion Outflow via Neutral atom imaging during a Substorm) was a sounding rocket mission launched Feb 7, 2013, at 0821 UTC from Poker Flat, AK into the expansion phase of an auroral substorm. VISIONS was expressly designed to take advantage of the sounding rocket trajectory (slow motion through the auroral features and vertical profile) and a unique combination of in situ and remote sensing to shed new light on the drivers of low-altitude ion outflow. VISIONS carried five instruments, which together with ground-based instrumentation, measure the relevant parameters for studying ion outflow: 1) a low-energy energetic neutral atom (ENA) imager, MILENA, to remotely sense ion outflow from 50 eV to 3 keV 2) an electrostatic analyzer for electrons from 3 eV - 30 keV 3) an electrostatic analyzer for ions from 1.5 eV - 15 eV 4) a four-channel visible imager (6300, 3914, H-Beta, and 8446) with 90 degree field of view for understanding electron precipitation over a wide area and for comparison with the ENA images 5) a fields and thermal plasma suite that

  13. Atmospheric OH reactivity in central London: observations, model predictions and estimates of in situ ozone production

    NASA Astrophysics Data System (ADS)

    Whalley, L. K.; Stone, D.; Bandy, B.; Dunmore, R.; Hamilton, J. F.; Hopkins, J.; Lee, J. D.; Lewis, A. C.; Heard, D. E.

    2015-11-01

    -generated intermediates worsened the agreement between modelled and observed OH concentrations (by 41 %) and the magnitude of in situ ozone production calculated from the production of RO2 was significantly lower (60 %). This work highlights that any future ozone abatement strategies should consider the role that biogenic emissions play alongside anthropogenic emissions in influencing London's air quality.

  14. Stratospheric Age Spectra and Mean Ages from In Situ Observations of Carbon Dioxide

    NASA Technical Reports Server (NTRS)

    Andrews, Arlyn E.; Boering, Kristie A.; Daube, Bruce C., Jr.; Wofsy, Steven C.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    In situ observations of CO2 obtained from 1992 through 2000 using the NASA ER-2 aircraft and high-altitude balloons show that seasonal and interannual variations in CO2 mixing ratios propagate from the troposphere into the lower stratosphere via the tropical tropopause, along with the long-term trend due to fossil fuel combustion. These signals spread laterally and vertically, providing detailed quantitative information about the transport history of sampled air. We have used these data to derive age spectra and mean ages that can be compared with results from models of the stratospheric circulation. For an air parcel at a point in the stratosphere, the age spectrum is defined as the probability distribution function for transit times from the tropical tropopause for each fluid element comprising the parcel. The mean age is the average transit time, corresponding to the first moment of the age spectrum. Age spectra have been derived for altitudes below approximately 20 km for the tropics and for northern midlatitudes where there is sufficient data and where the amplitudes of the seasonal and interannual oscillations in CO2 mixing ratios are large enough to be detected. Tropical age spectra are narrow, with seasonal variation indicating faster ascent during northern winter, consistent with a circulation driven by breaking of extratropical waves. The midlatitude CO2 data are consistent with bimodal age spectra, which could result from a subtropical "barrier" to horizontal exchange over a substantial altitude region. Seasonally resolved mean ages are available with nearly pole-to-pole coverage below 20 km and in the tropics and at middle and high northern latitudes up to the maximum altitude reached by the balloons (approximately 30 km). At ER-2 altitudes, steep meridional gradients in mean age are observed in the subtropics. Between 20 and 30 km, midlatitude air is approximately 2 years older than tropical air at the same altitude. The oldest air sampled was in the

  15. Constraining Annual Water Balance Estimates with Basin-Scale Observations from the Airborne Snow Observatory during the Current Californian Drought

    NASA Astrophysics Data System (ADS)

    Bormann, K.; Painter, T. H.; Marks, D. G.; Hedrick, A. R.; Deems, J. S.; Patterson, V.; McGurk, B. J.

    2015-12-01

    One of the great unknowns in mountain hydrology is how much water is stored within a seasonal snowpack at the basin scale. Quantifying mountain water resources is critical for assisting with water resource management, but has proven elusive due to high spatial and temporal variability of mountain snow cover, complex terrain, accessibility constraints and limited in-situ networks. The Airborne Snow Observatory (ASO, aso.jpl.nasa.gov) uses coupled airborne LiDAR and spectrometer instruments for high resolution snow depth retrievals which are used to derive unprecedented basin-wide estimates of snow water mass (snow water equivalent, SWE). ASO has been operational over key basins in the Sierra Nevada Mountains in California since 2013. Each operational year has been very dry, with precipitation in 2013 at 75% of average, 2014 at 50% of average and 2015 - the lowest snow year on record for the region. With vastly improved estimates of the snowpack water content from ASO, we can now for the first time conduct observation-based mass balance accounting of surface water in snow-dominated basins, and reconcile these estimates with observed reservoir inflows. In this study we use ASO SWE data to constrain mass balance accounting of basin annual water storages to quantify the water contained within the snowpack above the Hetch Hetchy water supply reservoir (Tuolumne River basin, California). The analysis compares and contrasts annual snow water volumes from observed reservoir inflows, snow water volume estimates from ASO, a physically based model that simulates the snowpack from meteorological inputs and a semi-distributed hydrological model. The study provides invaluable insight to the overall volume of water contained within a seasonal snowpack during a severe drought and how these quantities are simulated in our modelling systems. We envisage that this research will be of great interest to snowpack modellers, hydrologists, dam operators and water managers worldwide.

  16. Observation and Analysis of In Situ Carbonaceous Matter in Naklha. Part 2

    NASA Technical Reports Server (NTRS)

    Gibson, E. K., Jr.; Clemett, S. J.; Thomas-Kerpta, K. L.; McKay, D. S.; Wentworth, S. J.; Robert, F.; Verchovsky, A. B.; Wright, I. P.; Pillinger, C. T.; Rice, T.; VanLeer, B.

    2006-01-01

    The search for indigenous carbon components on Mars has been a challenge. The first attempt was the Viking GC-MS in situ experiment which gave inconclusive results at two sites on Mars [1]. After the discovery that the SNC meteorites were from Mars [2], [3-5] reported C isotopic compositional information which suggested a reduced C component present in the martian meteorites. [6 & 7] reported the presence of reduced C components (i.e., polycyclic aromatic hydrocarbons) associated with the carbonate globules in ALH84001. Jull et al. [8] noted in Nakhla there was an acid insoluble C component present with more than 75% of its C lacking any C-14, which is modern-day carbon. This C fraction was believed to be either indigenous martian or ancient meteoritic carbon. Fisk et al. [9, 10] have shown textural evidence along with C-enriched areas within fractures in Nakhla and ALH84001. To further understand the nature of possible indigenous reduced C components, we have carried out a variety of measurements on martian meteorites. For this presentation we will discuss only the Nakhla results. Interior samples from the Nakhla SNC meteorite, recently made available by the British Museum of Natural History, were analyzed. Petrographic examination [11, McKay et al., this volume] of Nakhla showed evidence of fractures (approx.0.5 micron wide) filled with dark brown to black dendritic material [Fig. 1] with characteristics similar to those observed by [10]. Iddingsite is also present along fractures in olivine. Fracture filling and dendritic material was examined by SEM-EDX, TEM-EDX, Focused Electron Beam microscopy, Laser Raman Spectroscopy, Nano-SIMS Ion Micro-probe, and Stepped-Combustion Static Mass Spectrometry.

  17. Hydration effects on gypsum dissolution revealed by in situ nanoscale atomic force microscopy observations

    NASA Astrophysics Data System (ADS)

    Burgos-Cara, A.; Putnis, C. V.; Rodriguez-Navarro, C.; Ruiz-Agudo, E.

    2016-04-01

    Recent work has suggested that the rates of mineral dissolution in aqueous solutions are dependent on the kinetics of dehydration of the ions building the crystal. Dehydration kinetics will be ultimately determined by the competition between ion-water and water-water interactions, which can be significantly modified by the presence of background ions in solution. At low ionic strength, the effect of electrolytes on ion-water (electrostatic) interactions will dominate (Kowacz et al., 2007). By performing macroscopic and in situ, microscopic (atomic force microscopy) dissolution experiments, the effect of background electrolytes on the dissolution kinetics of gypsum (CaSO4·2H2O) {0 1 0} cleavage surfaces is tested at constant, low ionic strength (IS = 0.05) and undersaturation (saturation index, SI = -0.045). Dissolution rates are systematically lower in the presence of 1:1 background electrolytes than in an electrolyte-free solution, regardless of the nature of the electrolyte tested. We hypothesize that stabilization of the hydration shell of calcium by the presence of background ions can explain this result, based on the observed correlations in dissolution rates with the ionic surface tension increment of the background ion in solution. Stabilization of the cation hydration shell should favor dissolution. However, in the case of strongly hydrated ions such as Ca2+, this has a direct entropic effect that reduces the overall ΔG of the system, so that dissolution is energetically less favorable. Overall, these results provide new evidence that supports cation dehydration being the rate-controlling step for gypsum dissolution, as proposed for other minerals such as barite, dolomite and calcite.

  18. Comparison of CME/Shock Propagation Models with Heliospheric Imaging and In Situ Observations

    NASA Astrophysics Data System (ADS)

    Zhao, Xinhua; Liu, Ying D.; Inhester, Bernd; Feng, Xueshang; Wiegelmann, Thomas; Lu, Lei

    2016-10-01

    The prediction of the arrival time for fast coronal mass ejections (CMEs) and their associated shocks is highly desirable in space weather studies. In this paper, we use two shock propagation models, i.e., Data Guided Shock Time Of Arrival (DGSTOA) and Data Guided Shock Propagation Model (DGSPM), to predict the kinematical evolution of interplanetary shocks associated with fast CMEs. DGSTOA is based on the similarity theory of shock waves in the solar wind reference frame, and DGSPM is based on the non-similarity theory in the stationary reference frame. The inputs are the kinematics of the CME front at the maximum speed moment obtained from the geometric triangulation method applied to STEREO imaging observations together with the Harmonic Mean approximation. The outputs provide the subsequent propagation of the associated shock. We apply these models to the CMEs on 2012 January 19, January 23, and March 7. We find that the shock models predict reasonably well the shock’s propagation after the impulsive acceleration. The shock’s arrival time and local propagation speed at Earth predicted by these models are consistent with in situ measurements of WIND. We also employ the Drag-Based Model (DBM) as a comparison, and find that it predicts a steeper deceleration than the shock models after the rapid deceleration phase. The predictions of DBM at 1 au agree with the following ICME or sheath structure, not the preceding shock. These results demonstrate the applicability of the shock models used here for future arrival time prediction of interplanetary shocks associated with fast CMEs.

  19. Spatio-Temporal Variability of Atmospheric CO2 as Observed from In-Situ Measurements over North America during NASA Field Campaigns (2004-2008)

    NASA Technical Reports Server (NTRS)

    Choi, Yonghoon; Vay, Stephanie A.; Woo, Jung-Hun; Choi, Kichul; Diskin, Glenn S.; Sachse, G. W.; Vadrevu, Krishna P.; Czech, E.

    2009-01-01

    Regional-scale measurements were made over the eastern United States (Intercontinental Chemical Transport Experiment - North America (INTEX-NA), summer 2004); Mexico (Megacity Initiative: Local and Global Research Observations (MILAGRO), March 2006); the eastern North Pacific and Alaska (INTEX-B May 2006); and the Canadian Arctic (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS), spring and summer 2008). For these field campaigns, instrumentation for the in situ measurement of CO2 was integrated on the NASA DC-8 research aircraft providing high-resolution (1 second) data traceable to the WMO CO2 mole fraction scale. These observations provide unique and definitive data sets via their intermediate-scale coverage and frequent vertical profiles (0.1 - 12 km) for examining the variability CO2 exhibits above the Earth s surface. A bottom-up anthropogenic CO2 emissions inventory (1deg 1deg) and processing methodology has also been developed for North America in support of these airborne science missions. In this presentation, the spatio-temporal distributions of CO2 and CO column values derived from the campaign measurements will be examined in conjunction with the emissions inventory and transport histories to aid in the interpretation of the CO2 observations.

  20. A High-Precision, Fast-Response Airborne CO2 Analyzer for In Situ Sampling From the Surface to the Middle Stratosphere

    NASA Technical Reports Server (NTRS)

    Daube, B. C., Jr.; Boering, K. A.; Andrews, Arlyn E.; Wofsy, S. C.

    2001-01-01

    Two in situ CO2 analyzers have been developed for deployment on the NASA ER-2 aircraft and on stratospheric balloons. The ER-2 instrument has had more than 150 flights during 21 deployments from 1992 to 2000, resulting in a dataset with nearly pole-to-pole coverage that includes data from all seasons in both hemispheres except austral summer. In-flight calibrations show that the typical long-term (i.e. flight-to-flight) precision of the instruments is better than plus or minus 0.1 ppmv. The flight standards are traceable to standards held by the Scripps Institute of Oceanography and the National Oceanic and Atmospheric Administration's Climate Monitoring and Diagnostics Laboratory. The balloon instrument has had 8 balloon flights since September 1996, providing the first in situ observations of CO2 above approx. 21 km. In addition, the balloon instrument has been flown onboard a Cessna Citation II aircraft for sampling between the surface and 10 km. In this paper, the instrumentation and calibration procedures for both instruments are described in detail. An intercomparison of the two instruments during the Photochemistry of Ozone Loss in the Arctic Region In Summer (POLARIS) project showed that, on average, the instruments agreed to within 0.05 ppmv.

  1. Remote and In Situ Observations of an Unusual Earth-Directed Coronal Mass Ejection from Multiple Viewpoints

    NASA Technical Reports Server (NTRS)

    Nieves-Chinchilla, T.; Colaninno, R.; Vourlidas, A.; Szabo, A.; Lepping, R. P.; Boardsen, S. A.; Anderson, B. J.; Korth, H.

    2012-01-01

    During June 16-21, 2010, an Earth-directed Coronal Mass Ejection (CME) event was observed by instruments onboard STEREO, SOHO, MESSENGER and Wind. This event was the first direct detection of a rotating CME in the middle and outer corona. Here, we carry out a comprehensive analysis of the evolution of the CME in the interplanetary medium comparing in-situ and remote observations, with analytical models and three-dimensional reconstructions. In particular, we investigate the parallel and perpendicular cross section expansion of the CME from the corona through the heliosphere up to 1 AU. We use height-time measurements and the Gradual Cylindrical Shell (GCS) technique to model the imaging observations, remove the projection effects, and derive the 3-dimensional extent of the event. Then, we compare the results with in-situ analytical Magnetic Cloud (MC) models, and with geometrical predictions from past works. We nd that the parallel (along the propagation plane) cross section expansion agrees well with the in-situ model and with the Bothmer & Schwenn [1998] empirical relationship based on in-situ observations between 0.3 and 1 AU. Our results effectively extend this empirical relationship to about 5 solar radii. The expansion of the perpendicular diameter agrees very well with the in-situ results at MESSENGER ( 0:5 AU) but not at 1 AU. We also find a slightly different, from Bothmer & Schwenn [1998], empirical relationship for the perpendicular expansion. More importantly, we find no evidence that the CME undergoes a significant latitudinal over-expansion as it is commonly assumed

  2. Atmospheric OH reactivity in central London: observations, model predictions and estimates of in situ ozone production

    NASA Astrophysics Data System (ADS)

    Whalley, Lisa K.; Stone, Daniel; Bandy, Brian; Dunmore, Rachel; Hamilton, Jacqueline F.; Hopkins, James; Lee, James D.; Lewis, Alastair C.; Heard, Dwayne E.

    2016-02-01

    9) (particularly α-pinene and limonene) and model-generated intermediates increases the modelled OH concentrations by 41 %, and the magnitude of in situ ozone production calculated from the production of RO2 was significantly lower (60 %). This work highlights that any future ozone abatement strategies should consider the role that biogenic emissions play alongside anthropogenic emissions in influencing London's air quality.

  3. The effect of electrolytes on dolomite dissolution: nanoscale observations using in situ Atomic Force Microscopy

    NASA Astrophysics Data System (ADS)

    Urosevic, Maja; Ruiz-Agudo, Encarnacion; Putnis, Christine V.; Cardell, Carolina; Rodriguez-Navarro, Carlos; Putnis, Andrew

    2010-05-01

    carbonate rocks, both in the natural environment, as well as in stone buildings and statuary, where the amount of solutes in pore waters is significant and can vary depending on evaporation and condensation phenomena. References Higgins, S.R.; Hu, X. Self-limiting growth on dolomite: Experimental observations with in situ atomic force microscopy. Geochimica et Cosmochimica Acta, 2005, 69 (8), 2085-2094. Morse, J.W.; Arvidson, R.S. The dissolution kinetics of major sedimentary carbonate minerals. Earth-Science Reviews, 2002, 58, 51-84. Ruiz-Agudo, E.; Kowacz, M.; Putnis, C.V.; Putnis, A. The role of background electrolytes on the kinetics and mechanism of calcite dissolution. Geochimica et Cosmochimica Acta, 2010, 74, 1256-1267.

  4. RECONSTRUCTING CORONAL MASS EJECTIONS WITH COORDINATED IMAGING AND IN SITU OBSERVATIONS: GLOBAL STRUCTURE, KINEMATICS, AND IMPLICATIONS FOR SPACE WEATHER FORECASTING

    SciTech Connect

    Liu Ying; Luhmann, Janet G.; Lin, Robert P.; Bale, Stuart D.; Thernisien, Arnaud; Vourlidas, Angelos; Davies, Jackie A.

    2010-10-20

    We reconstruct the global structure and kinematics of coronal mass ejections (CMEs) using coordinated imaging and in situ observations from multiple vantage points. A forward modeling technique, which assumes a rope-like morphology for CMEs, is used to determine the global structure (including orientation and propagation direction) from coronagraph observations. We reconstruct the corresponding structure from in situ measurements at 1 AU with the Grad-Shafranov method, which gives the flux-rope orientation, cross section, and a rough knowledge of the propagation direction. CME kinematics (propagation direction and radial distance) during the transit from the Sun to 1 AU are studied with a geometric triangulation technique, which provides an unambiguous association between solar observations and in situ signatures; a track fitting approach is invoked when data are available from only one spacecraft. We show how the results obtained from imaging and in situ data can be compared by applying these methods to the 2007 November 14-16 and 2008 December 12 CMEs. This merged imaging and in situ study shows important consequences and implications for CME research as well as space weather forecasting: (1) CME propagation directions can be determined to a relatively good precision as shown by the consistency between different methods; (2) the geometric triangulation technique shows a promising capability to link solar observations with corresponding in situ signatures at 1 AU and to predict CME arrival at the Earth; (3) the flux rope within CMEs, which has the most hazardous southward magnetic field, cannot be imaged at large distances due to expansion; (4) the flux-rope orientation derived from in situ measurements at 1 AU may have a large deviation from that determined by coronagraph image modeling; and (5) we find, for the first time, that CMEs undergo a westward migration with respect to the Sun-Earth line at their acceleration phase, which we suggest is a universal

  5. Airborne DOAS observations of tropospheric NO2 using an UltraLight Trike and flux calculation

    NASA Astrophysics Data System (ADS)

    Constantin, Daniel-Eduard; Voiculescu, Mirela; Merlaud, Alexis; Dragomir, Carmelia; Georgescu, Lucian; Hendrick, Francois; Van Roozendael, Michel

    2016-04-01

    In this paper we present airborne DOAS observations of tropospheric NO2 using an Ultralight Trike (ULT) and associated flux calculation. The instrument onboard the ULT was developed for measuring the tropospheric NO2 Vertical Column Density (VCD). Measurements were performed for several days during 2011-2014, in a region SE of Romania, over the cities of Galati (45.43°N, 28.03°E) and Braila (45.26°N, 27.95°E). Measurements of the NO2 column in the same area were performed using car-DOAS observations. The correlation between the tropospheric NO2 VCD from airborne and mobile ground-based DOAS observations was used to validate the airborne observations. A specific AMF for each case was calculated using the radiative transfer model (RTM) UVspec/DISORT. We present also a comparison between SCDstrato derived from DOMINO (Dutch OMI NO2) and the SCDstrato obtained from ground and airborne measurements. Due to the mobility and flexibility of the ULT flights, this aerial platform provides a promising tool for satellite validation, especially for space observations by high resolution sensors such as the future TROPOMI instrument. A key added value of the ULT-DOAS, illustrated in this work, is the capacity to investigate the spatial variability of NO2 inside the horizontal extent of satellite pixels, e.g. above plant exhaust plumes.

  6. In Situ Observations and Sampling of Volcanic Emissions with Unmanned Aircraft: A NASA/UCR Case Study at Turrialba Volcano, Costa Rica

    NASA Technical Reports Server (NTRS)

    Pieri, David; Diaz, Jorge Andres; Bland, Geoffrey; Fladeland, Matthew; Madrigal, Yetty; Corrales, Ernesto; Alan, Alfredo; Alegria, Oscar; Realmuto, Vincent; Miles, Ted

    2011-01-01

    Burgeoning new technology in the design and development of robotic aircraft-unmanned aerial vehicles (UAVs)-presents unprecedented opportunities for the volcanology community to observe, measure, and sample eruption plumes and drifting volcanic clouds in situ. While manned aircraft can sample dilute parts of such emissions, demonstrated hazards to air breathing, and most particularly turbine, engines preclude penetration of the zones of highest ash concentrations. Such areas within plumes are often of highest interest with respect to boundary conditions of applicable mass-loading retrieval models, as well as Lagrangian, Eulerian, and hybrid transport models used by hazard responders to predict plume trajectories, particularly in the context of airborne hazards. Before the 2010 Ejyafyallajokull eruption in Iceland, ICAO zero-ash-tolerance rules were typically followed, particularly for relatively uncrowded Pacific Rim airspace, and over North and South America, where often diversion of aircraft around ash plumes and clouds was practical. The 2010 eruption in Iceland radically changed the paradigm, in that critical airspace over continental Europe and the United Kingdom were summarily shut by local civil aviation authorities and EURO CONTROL. A strong desire emerged for better real-time knowledge of ash cloud characteristics, particularly ash concentrations, and especially for validation of orbital multispectral imaging. UAV platforms appear to provide a viable adjunct, if not a primary source, of such in situ data for volcanic plumes and drifting volcanic clouds from explosive eruptions, with prompt and comprehensive application to aviation safety and to the basic science of volcanology. Current work is underway in Costa Rica at Turrialba volcano by the authors, with the goal of developing and testing new small, economical UAV platforms, with miniaturized instrument payloads, within a volcanic plume. We are underway with bi-monthly deployments of tethered SO2-sondes

  7. Evaluation of Mixed-Phase Microphysics Within Winter Storms Using Field Data and In Situ Observations

    NASA Technical Reports Server (NTRS)

    Colle, Brian A.; Molthan, Andrew; Yu, Ruyi; Nesbitt, Steven

    2014-01-01

    Snow prediction within models is sensitive to the snow densities, habits, and degree of riming within the BMPs. Improving these BMPs is a crucial step toward improving both weather forecasting and climate predictions. Several microphysical schemes in the Weather Research and Forecasting (WRF) model down to 1.33-km grid spacing are evaluated using aircraft, radar, and ground in situ data from the Global Precipitation Mission Cold-season Precipitation Experiment (GCPEx) experiment over southern Ontario, as well as a few years (12 winter storms) of surface measurements of riming, crystal habit, snow density, and radar measurements at Stony Brook, NY (SBNY on north shore of Long Island) during the 2009-2012 winter seasons. Surface microphysical measurements at SBNY were taken every 15 to 30 minutes using a stereo microscope and camera, and snow depth and snow density were also recorded. During these storms, a vertically-pointing Ku band radar was used to observe the vertical evolution of reflectivity and Doppler vertical velocities. The GCPex presentation will focus on verification using aircraft spirals through warm frontal snow band event on 18 February 2012. All the BMPs realistically simulated the structure of the band and the vertical distribution of snow/ice aloft, except the SBU-YLIN overpredicted slightly and Thompson (THOM) underpredicted somewhat. The Morrison (MORR) scheme produced the best slope size distribution for snow, while the Stony Brook (SBU) underpredicted and the THOM slightly overpredicted. Those schemes that have the slope intercept a function of temperature (SBU and WSM6) tended to perform better for that parameter than others, especially the fixed intercept in Goddard. Overall, the spread among BMPs was smaller than in other studies, likely because there was limited riming with the band. For the 15 cases at SBNY, which include moderate and heavy riming events, the non-spherical snow assumption (THOM and SBU-YLIN) simulated a more realistic

  8. Characterizing supraglacial meltwater channel hydraulics on the Greenland Ice Sheet from in situ observations

    USGS Publications Warehouse

    Gleason, Colin J.; Smith, Laurence C.; Chu, Vena W.; Legleiter, Carl; Pitcher, Lincoln H.; Overstreet, Brandon T.; Rennermalm, Asa K.; Forster, Richard R.; Yang, Kang

    2016-01-01

    Supraglacial rivers on the Greenland ice sheet (GrIS) transport large volumes of surface meltwater toward the ocean, yet have received relatively little direct research. This study presents field observations of channel width, depth, velocity, and water surface slope for nine supraglacial channels on the southwestern GrIS collected between 23 July and 20 August, 2012. Field sites are located up to 74 km inland and span 494-1485 m elevation, and contain measured discharges larger than any previous in situ study: from 0.006 to 23.12 m3/s in channels 0.20 to 20.62 m wide. All channels were deeply incised with near vertical banks, and hydraulic geometry results indicate that supraglacial channels primarily accommodate greater discharges by increasing velocity. Smaller streams had steeper water surface slopes (0.74-8.83%) than typical in terrestrial settings, yielding correspondingly high velocities (0.40-2.60 m/s) and Froude numbers (0.45-3.11) with supercritical flow observed in 54% of measurements. Derived Manning's n values were larger and more variable than anticipated from channels of uniform substrate, ranging from 0.009 to 0.154 with a mean value of 0.035 +/- 0.027 despite the absence of sediment, debris, or other roughness elements. Ubiquitous micro-depressions in shallow sections of the channel bed may explain some of these roughness values. However, we find that other, unobserved sources of flow resistance likely contributed to these elevated n values: future work should explicitly consider additional sources of flow resistance beyond bed roughness in supraglacial channels. We conclude that hydraulic modelling for these channels must allow for both sub- and supercritical flow, and most importantly must refrain from assuming that all ice-substrate channels exhibit similar hydraulic behavior, especially for Froude numbers and Manning's n. Finally, this study highlights that further theoretical and empirical work on supraglacial channel hydraulics is

  9. Airborne Ethane Observations over the Barnett and Bakken Shale Formations: Quantification of Ethane Fluxes and Attribution of Methane Emissions

    NASA Astrophysics Data System (ADS)

    Smith, M. L.; Kort, E. A.; Karion, A.; Sweeney, C.; Peischl, J.; Ryerson, T. B.

    2014-12-01

    The largest emissions sources of methane, a potent greenhouse gas and the primary component of natural gas, are the fossil fuel sector and microbial processes that occur in agricultural settings, landfills, and wetlands. Attribution of methane to these different source sectors has proven difficult, as evidenced by persistent disagreement between the annual emissions estimated from atmospheric observations (top-down) and from inventories (bottom-up). Given the rapidly changing natural gas infrastructure in North America, and the implications of associated rapid changes in emissions of methane for climate, it is crucial we improve our ability to quantify and understand current and future methane emissions. Here, we present evidence that continuous in-situ airborne observations of ethane, which is a tracer for fossil fuel emissions, are a new and useful tool for attribution of methane emissions to specific source sectors. Additionally, with these new airborne observations we present the first tightly constrained ethane emissions estimates of oil and gas production fields using the well-known mass balance method. The ratios of ethane-to-methane (C2H6:CH4) of specific methane emissions sources were studied over regions of high oil and gas production from the Barnett, TX and Bakken, ND shale plays, using continuous (1Hz frequency) airborne ethane measurements paired with simultaneous methane measurements. Despite the complex mixture of sources in the Barnett region, the methane emissions were well-characterized by distinct C2H6:CH4 relationships indicative of a high-ethane fossil fuel source (e.g., "wet" gas), a low-ethane fossil fuel source (e.g., "dry" gas), and an ethane-free, or microbial source. The defined set of C2H6:CH4 that characterized the emissions input to the atmosphere was used in conjunction with the total ethane and methane fluxes to place bounds on the fraction of methane emissions attributable to each source. Additionally, substantial ethane fluxes

  10. Bimodal distribution of free tropospheric ozone over the tropical western Pacific revealed by airborne observations

    NASA Astrophysics Data System (ADS)

    Pan, L. L.; Honomichl, S. B.; Randel, W. J.; Apel, E. C.; Atlas, E. L.; Beaton, S. P.; Bresch, J. F.; Hornbrook, R.; Kinnison, D. E.; Lamarque, J.-F.; Saiz-Lopez, A.; Salawitch, R. J.; Weinheimer, A. J.

    2015-09-01

    A recent airborne field campaign over the remote western Pacific obtained the first intensive in situ ozone sampling over the warm pool region from oceanic surface to 15 km altitude (near 360 K potential temperature level). The new data set quantifies ozone in the tropical tropopause layer under significant influence of convective outflow. The analysis further reveals a bimodal distribution of free tropospheric ozone mixing ratio. A primary mode, narrowly distributed around 20 ppbv, dominates the troposphere from the surface to 15 km. A secondary mode, broadly distributed with a 60 ppbv modal value, is prominent between 3 and 8 km (320 K to 340 K potential temperature levels). The latter mode occurs as persistent layers of ozone-rich drier air and is characterized by relative humidity under 45%. Possible controlling mechanisms are discussed. These findings provide new insight into the physical interpretation of the "S"-shaped mean ozone profiles in the tropics.

  11. Extinction coefficients from lidar observations in ice clouds compared to in-situ measurements from the Cloud Integrating Nephelometer during CRYSTAL-FACE

    NASA Technical Reports Server (NTRS)

    Noel, Vincent; Winker, D. M.; Garrett, T. J.; McGill, M.

    2005-01-01

    This paper presents a comparison of volume extinction coefficients in tropical ice clouds retrieved from two instruments : the 532-nm Cloud Physics Lidar (CPL), and the in-situ probe Cloud Integrating Nephelometer (CIN). Both instruments were mounted on airborne platforms during the CRYSTAL-FACE campaign and took measurements in ice clouds up to 17km. Coincident observations from three cloud cases are compared : one synoptically-generated cirrus cloud of low optical depth, and two ice clouds located on top of convective systems. Emphasis is put on the vertical variability of the extinction coefficient. Results show small differences on small spatial scales (approx. 100m) in retrievals from both instruments. Lidar retrievals also show higher extinction coefficients in the synoptic cirrus case, while the opposite tendency is observed in convective cloud systems. These differences are generally variations around the average profile given by the CPL though, and general trends on larger spatial scales are usually well reproduced. A good agreement exists between the two instruments, with an average difference of less than 16% on optical depth retrievals.

  12. In situ observation of crystallographic preferred orientation of deforming olivine at high pressure and high temperature

    NASA Astrophysics Data System (ADS)

    Ohuchi, T.; Nishihara, Y.; Seto, Y.; Kawazoe, T.; Nishi, M.; Maruyama, G.; Hashimoto, M.; Higo, Y.; Funakoshi, K. I.; Suzuki, A.; Kikegawa, T.; Irifune, T.

    2015-12-01

    Olivine is the main constituent mineral in Earth's upper mantle, and its crystallographic preferred orientation (CPO) controls the seismic anisotropy in the upper mantle. Because the relationship between fabric strength and seismic anisotropy shows an exponential form (Ismail and Mainprice, 1998), seismic anisotropy in the upper mantle is expected to have an upperlimit value. Hansen et al., (2014) demonstrated that a steady-state fabric of olivine is not reached until a very large shear strain (γ> 10) and fabric strength of olivine increases up to the J-index of 10-30 at 0.3 GPa. However, the strain dependency on the fabric strength of olivine needs to be evaluated at asthenospheric upper mantle pressures (2-13 GPa) because the relative activity of each slip system in olivine changes depending on pressure (e.g., Raterron et al., 2007). We experimentally evaluated the strain dependency of fabric strength of olivine in simple-shear geometry under upper mantle conditions (pressures of 1.3-3.8 GPa and temperatures of 1223-1573 K). The CPO of olivine was calculated from in-situ two-dimensional X-ray diffraction patterns. In the calculation, we simulated the optimized CPO which reproduces the two-dimensional X-ray diffraction pattern adopted from the experiments. The steady-state fabric strength of the A-type fabric was achieved within total shear strain of γ = 2. At strains higher than γ = 1, an increase in concentration of the [010] axes mainly contributes to an increase in fabric strength. At strains higher than γ = 2, the magnitude of VSH/VSV (i.e., ratio of horizontally and vertically polarized shear wave velocities) scarcely increased in most of the runs. The VSH/VSV of peridotite having the steady-state A-type olivine fabric coincides with that of recent global one-dimensional models under the assumption of horizontal flow, suggesting that the seismic anisotropy observed in the shallow upper mantle is mostly explained by the development of A-type olivine

  13. In-situ observation of the transformation of amorphous calcium phosphate to crystalline hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Stammeier, Jessica; Hippler, Dorothee; Mavromatis, Vasileios; Sacher, Stephan; Dietzel, Martin

    2016-04-01

    Amorphous calcium phosphate (Ca3(PO4)2*nH2O; ACP) is often a precursor phase of the mineral (hydroxy-) apatite (Ca5(PO4)3(OH)) that can be formed in natural settings during both authigenic and biogenic mineral formation. Particularly, in the biomineralization process of fish tissue, ACP has shown to be an important transient phase. In solution ACP rapidly transforms into the crystalline phase. The transformation rate highly depends on the physico-chemical conditions of the solution: Ca & P availability, pH and temperature. In natural settings Ca can be provided by different sources: from (1) seawater, (2) porewater, or (3) diagenetically-altered carbonates, whereas local supersaturation of P can be induced by microbial activity. In this study, we performed phosphate precipitation experiments in order to monitor the transformation process of the ACP to crystalline hydroxyapatite (HAP) using in-situ Raman spectroscopy. During the experiments the temperature was kept constant at 20.0 ± 0.01 ° C and pH at 9 ± 0.1. 50 ml of 0.3 CaCl 2H2O was titrated at a rate of 5 ml/min to an equal volume of 0.2 M Na2HPO4. The pH was kept constant by titration of 1 M NaOH. During the experiment samples were taken from the solution and instantly filtered. The obtained solid samples were lyophilized and analyzed with XRD, ATR and SEM. The respective solution samples were analyzed using ion chromatography and ICP OES, coupling the spectroscopic data with detailed solution chemistry data. We observed transformation of ACP to HAP to occur within 14 hours, illustrated in a clear peak shift in Raman spectra from 950 cm-1 to 960 cm-1. The obtained results are discussed in the aspects of distribution of major elements during the formation of phosphates and/or the diagenetic alteration of carbonates to phosphates in geologic settings. Financial support by DFG-FG 736 and NAWI Graz is kindly acknowledged.

  14. Aerosol cloud interactions in southeast Pacific stratocumulus: satellite observations, in situ data and regional modeling

    NASA Astrophysics Data System (ADS)

    George, Rhea

    The influence of anthropogenic aerosols on cloud radiative properties in the persistent southeast Pacific stratocumulus deck is investigated using MODIS satellite observations, in situ data from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx), and WRF-Chem, a regional model with interactive chemistry and aerosols. An albedo proxy is derived based on the fractional coverage of low cloud (a macrophysical field) and the cloud albedo, with the latter broken down into contributions from microphysics (cloud droplet concentration, Nd and macrophysics (liquid water path). Albedo variability is dominated by low cloud fraction variability, except within 10-15° of the South American coast, where cloud albedo variability contributes significantly. Covariance between cloud fraction and cloud albedo also contributes significantly to the variance in albedo, which highlights how complex and inseparable the factors controlling albedo are. N d variability contributes only weakly, which emphasizes that attributing albedo variability to the indirect effects of aerosols against the backdrop of natural meteorological variability is extremely challenging. Specific cases of aerosol changes can have strong impacts on albedo. We identify a pathway for periodic anthropogenic aerosol transport to the unpolluted marine stratocumulus >1000 km offshore, which strongly enhances Nd and albedo in zonally-elongated 'hook'-shaped arc. Hook development occurs with Nd increasing to polluted levels over the remote ocean primarily due to entrainment of a large number of small aerosols from the free troposphere that contribute a relatively small amount of aerosol mass to the marine boundary layer. Strong, deep offshore flow needed to transport continental aerosols to the remote ocean is favored by a trough approaching the South American coast and a southeastward shift of the climatological subtropical high pressure system. DMS significantly influences the aerosol number and

  15. Variability and budget of CO2 in Europe: analysis of the CAATER airborne campaigns - Part 1: Observed variability

    NASA Astrophysics Data System (ADS)

    Xueref-Remy, I.; Messager, C.; Filippi, D.; Pastel, M.; Nedelec, P.; Ramonet, M.; Paris, J. D.; Ciais, P.

    2011-06-01

    Atmospheric airborne measurements of CO2 are very well suited for estimating the time-varying distribution of carbon sources and sinks at the regional scale due to the large geographical area covered over a short time. We present here an analysis of two cross-European airborne campaigns carried out on 23-26 May 2001 (CAATER-1) and 2-3 October 2002 (CAATER-2) over Western Europe. The area covered during CAATER-1 and CAATER-2 was 4° W to 14° E long; 44° N to 52° N lat and 1° E to 17° E long; 46° N to 52° N lat respectively. High precision in situ CO2, CO and Radon 222 measurements were recorded. Flask samples were collected during both campaigns to cross-validate the in situ data. During CAATER-1 and CAATER-2, the mean CO2 concentration was 370.1 ± 4.0 (1-σ standard deviation) ppm and 371.7 ± 5.0 (1-σ) ppm respectively. A HYSPLIT back-trajectories analysis shows that during CAATER 1, northwesterly winds prevailed. In the planetary boundary layer (PBL) air masses became contaminated over Benelux and Western Germany by emissions from these highly urbanized areas, reaching about 380 ppm. Air masses passing over rural areas were depleted in CO2 because of the photosynthesis activity of the vegetation, with observations as low as 355 ppm. During CAATER-2, the back-trajectory analysis showed that air masses were distributed among the 4 sectors. Air masses were enriched in CO2 and CO over anthropogenic emission spots in Germany but also in Poland, as these countries have part of the most CO2-emitting coal-based plants in Europe. Simultaneous measurements of in situ CO2 and CO combined with back-trajectories helped us to distinguish between fossil fuel emissions and other CO2 sources. The ΔCO/ΔCO2 ratios (R2 = 0.33 to 0.88, slopes = 2.42 to 10.37), calculated for anthropogenic-influenced air masses over different countries/regions matched national inventories quite well, showing that airborne measurements can help to identify the origin of fossil fuel emissions

  16. WaterML, an Information Standard for the Exchange of in-situ hydrological observations

    NASA Astrophysics Data System (ADS)

    Valentine, D.; Taylor, P.; Zaslavsky, I.

    2012-04-01

    The WaterML 2.0 Standards Working Group (SWG), working within the Open Geospatial Consortium (OGC) and in cooperation with the joint OGC-World Meteorological Organization (WMO) Hydrology Domain Working Group (HDWG), has developed an open standard for the exchange of water observation data; WaterML 2.0. The focus of the standard is time-series data, commonly generated from in-situ style monitoring. This is high value data for hydrological applications such as flood forecasting, environmental reporting and supporting hydrological infrastructure (e.g. dams, supply systems), which is commonly exchanged, but a lack of standards inhibits efficient reuse and automation. The process of developing WaterML required doing a harmonization analysis of existing standards to identify overlapping concepts and come to agreement on a harmonized definition. Generally the formats captured similar requirements, all with subtle differences, such as how time-series point metadata was handled. The in-progress standard WaterML 2.0 incorporates the semantics of the hydrologic information: location, procedure, and observations, and is implemented as an application schema of the Geography Markup Language version 3.2.1, making use of the OGC Observations & Measurements standards. WaterML2.0 is designed as an extensible schema to allow encoding of data to be used in a variety of exchange scenarios. Example areas of usage are: exchange of data for operational hydrological monitoring programs; supporting operation of infrastructure (e.g. dams, supply systems); cross-border exchange of observational data; release of data for public dissemination; enhancing disaster management through data exchange; and exchange in support of national reporting The first phase of WaterML2.0 focused on structural definitions allowing for the transfer of time-series, with less work on harmonization of vocabulary items such as quality codes. Vocabularies from various organizations tend to be specific and take time to

  17. Validation of Satellite Observed Soil Moisture Using In-Situ Measurements

    NASA Astrophysics Data System (ADS)

    van der Velde, Rogier; Yu, Xiaolong; Zheng, Donghai; Benninga, Harm-Jan F.; Shahmohamadi, Mohamad Ali; Hendriks, Dimmie; Hunnink, Joachim; Coliander, Andreas; Jackson, Thomas J.; Bindlish, Rajat; Chan, Steven K.; Su, Bob

    2016-08-01

    Although with in-situ techniques soil moisture can be measured reliably at point-scale, it remains a challengeto translate a collection of point measurements tothe scale of satellite footprints (> 10 km). Spatially distributed soil moisture simulations by the Dutch Landelijk Hydro-logisch Model (LHM, De Lange et al. 2014) are here employed for this task. The upscaled in- situ measurements are subsequently utilized to assess the CATDS (Centre Aval de Traitement des Données SMOS, Soil Moisture and Ocean Salinity, Jacquette et al. 2010) L3 and the NASA SMAP (Soil Moisture Active Passive)L2 radiometer-only soil moisture products (O'Neill et al. 2015).

  18. In situ stress observation in oxide films and how tensile stress influences oxygen ion conduction

    PubMed Central

    Fluri, Aline; Pergolesi, Daniele; Roddatis, Vladimir; Wokaun, Alexander; Lippert, Thomas

    2016-01-01

    Many properties of materials can be changed by varying the interatomic distances in the crystal lattice by applying stress. Ideal model systems for investigations are heteroepitaxial thin films where lattice distortions can be induced by the crystallographic mismatch with the substrate. Here we describe an in situ simultaneous diagnostic of growth mode and stress during pulsed laser deposition of oxide thin films. The stress state and evolution up to the relaxation onset are monitored during the growth of oxygen ion conducting Ce0.85Sm0.15O2-δ thin films via optical wafer curvature measurements. Increasing tensile stress lowers the activation energy for charge transport and a thorough characterization of stress and morphology allows quantifying this effect using samples with the conductive properties of single crystals. The combined in situ application of optical deflectometry and electron diffraction provides an invaluable tool for strain engineering in Materials Science to fabricate novel devices with intriguing functionalities. PMID:26912416

  19. Synoptic Estimates of Waves and Currents via Real-Time Assimilation of In-Situ Observations

    DTIC Science & Technology

    2003-09-30

    model physics that are necessary for the success of the data assimilation procedure ; 2. Perform a full-scale test of the data assimilation algorithm... assimilation procedure . APPROACH The approach for the assimilation algorithm will be to assimilate time-series data obtained from in-situ...the assimilation procedure . IMPACT/APPLICATIONS The results of the proposed program will provide the capability of monitoring near-shore waves

  20. Synoptic Estimates of Waves and Currents via Real-Time Assimilation of In-Situ Observations

    DTIC Science & Technology

    2003-09-30

    the assimilation procedure , improvements in the numerical implementation of the extended Boussinesq model and its adjoint, and addition of improved... procedure . The assimilation procedure makes use of the adjoint to the Boussinesq equations, which are implemented in a numerically similar manner to the...develop the in-situ data assimilation procedure . 2 Figure 1 Surface elevation field for a 6 x 7 km region around the NCEX site in La Jolla, CA

  1. In-situ observation of dynamic recrystallization in the bulk of zirconium alloy.

    SciTech Connect

    Liss, K.-D.; Garbe, U.; Li, H. J.; Schambron, T.; Almer, J. D.; Yan, K.; Australian Nuclear Science and Tech. Organisation; Univ. of Wollongong

    2009-08-01

    Dynamic recrystallization and related effects have been followed in situ and in real time while a metal undergoes rapid thermo-mechanical processing. Statistics and orientation correlations of embedded/bulk material grains were deduced from two-dimensional X-ray diffraction patterns and give deep insight into the formation of the microstructure. Applications are relevant in materials design, simulation, and in geological systems.

  2. In-Situ Observation of Directional Solidifications of Al-Cu Alloys During Parabolic Flight Campaigns

    NASA Astrophysics Data System (ADS)

    Abou-Khalil, L.; Salloum-Abou-Jaoude, G.; Reinhart, G.; Pickmann, C.; Zimmermann, G.; Houltz, Y.; Li, J.; Janson, O.; Nguyen-Thi, H.

    2015-09-01

    It is well known that the final properties of materials are strongly related to the microstructures formed during growth and to the accompanying segregation, both being very sensitive to the natural hydrodynamic movements in the melt induced by gravity. Therefore, a deeper understanding of gravity effects on the solidification microstructure is of great importance for industrial applications. In the framework of the ESA-MAP project entitled XRMON (in-situ X-Ray MONitoring of advanced metallurgical processes under microgravity and terrestrial conditions), directional solidification experiments with in situ X-ray radiography were carried out during the 60th and 61st ESA — PF campaigns onboard the Airbus A300 operated by Novespace. Parabolic flights offer several successions of periods with normal gravity between two parabolas, and hyper gravity and microgravity during each parabola, which allows the impact of gravity level variations on the solidification microstructures to be investigated. For this purpose, a dedicated apparatus was designed and developed in collaboration with SSC (Swedish Space Corporation). XRMON-PFF (Parabolic Flight Facility) includes a Bridgman furnace dedicated to the solidification of Al-based alloys with an X-ray device that enables in situ characterization. Columnar and/or equiaxed growth of refined and non-refined Al2Owt.%Cu alloys were investigated and X-ray radiography was successfully used to assess the effect of periodic variations of the gravity level on the solidification microstructure formation. Preliminary results confirmed the strong influence of gravity on the solidification microstructure development.

  3. In Situ STEM-EELS observation of nanoscale interfacial phenomena in all-solid-state batteries

    DOE PAGES

    Wang, Ziying; Xin, Huolin L.; Santhanagopalan, Dhamodaran; ...

    2016-05-03

    Behaviors of functional interfaces are crucial factors in the performance and safety of energy storage and conversion devices. Indeed, solid electrode–solid electrolyte interfacial impedance is now considered the main limiting factor in all-solid-state batteries rather than low ionic conductivity of the solid electrolyte. Here, we present a new approach to conducting in situ scanning transmission electron microscopy (STEM) coupled with electron energy loss spectroscopy (EELS) in order to uncover the unique interfacial phenomena related to lithium ion transport and its corresponding charge transfer. Our approach allowed quantitative spectroscopic characterization of a galvanostatically biased electrochemical system under in situ conditions. Usingmore » a LiCoO2/LiPON/Si thin film battery, an unexpected structurally disordered interfacial layer between LiCoO2 cathode and LiPON electrolyte was discovered to be inherent to this interface without cycling. During in situ charging, spectroscopic characterization revealed that this interfacial layer evolved to form highly oxidized Co ions species along with lithium oxide and lithium peroxide species. Here, these findings suggest that the mechanism of interfacial impedance at the LiCoO2/LiPON interface is caused by chemical changes rather than space charge effects. Insights gained from this technique will shed light on important challenges of interfaces in all-solid-state energy storage and conversion systems and facilitate improved engineering of devices operated far from equilibrium.« less

  4. In Situ STEM-EELS Observation of Nanoscale Interfacial Phenomena in All-Solid-State Batteries.

    PubMed

    Wang, Ziying; Santhanagopalan, Dhamodaran; Zhang, Wei; Wang, Feng; Xin, Huolin L; He, Kai; Li, Juchuan; Dudney, Nancy; Meng, Ying Shirley

    2016-06-08

    Behaviors of functional interfaces are crucial factors in the performance and safety of energy storage and conversion devices. Indeed, solid electrode-solid electrolyte interfacial impedance is now considered the main limiting factor in all-solid-state batteries rather than low ionic conductivity of the solid electrolyte. Here, we present a new approach to conducting in situ scanning transmission electron microscopy (STEM) coupled with electron energy loss spectroscopy (EELS) in order to uncover the unique interfacial phenomena related to lithium ion transport and its corresponding charge transfer. Our approach allowed quantitative spectroscopic characterization of a galvanostatically biased electrochemical system under in situ conditions. Using a LiCoO2/LiPON/Si thin film battery, an unexpected structurally disordered interfacial layer between LiCoO2 cathode and LiPON electrolyte was discovered to be inherent to this interface without cycling. During in situ charging, spectroscopic characterization revealed that this interfacial layer evolved to form highly oxidized Co ions species along with lithium oxide and lithium peroxide species. These findings suggest that the mechanism of interfacial impedance at the LiCoO2/LiPON interface is caused by chemical changes rather than space charge effects. Insights gained from this technique will shed light on important challenges of interfaces in all-solid-state energy storage and conversion systems and facilitate improved engineering of devices operated far from equilibrium.

  5. In Situ STEM-EELS observation of nanoscale interfacial phenomena in all-solid-state batteries

    SciTech Connect

    Wang, Ziying; Xin, Huolin L.; Santhanagopalan, Dhamodaran; Zhang, Wei; Wang, Feng; He, Kai; Li, Juchuan; Dudney, Nancy; Meng, Ying Shirley

    2016-05-03

    Behaviors of functional interfaces are crucial factors in the performance and safety of energy storage and conversion devices. Indeed, solid electrode–solid electrolyte interfacial impedance is now considered the main limiting factor in all-solid-state batteries rather than low ionic conductivity of the solid electrolyte. Here, we present a new approach to conducting in situ scanning transmission electron microscopy (STEM) coupled with electron energy loss spectroscopy (EELS) in order to uncover the unique interfacial phenomena related to lithium ion transport and its corresponding charge transfer. Our approach allowed quantitative spectroscopic characterization of a galvanostatically biased electrochemical system under in situ conditions. Using a LiCoO2/LiPON/Si thin film battery, an unexpected structurally disordered interfacial layer between LiCoO2 cathode and LiPON electrolyte was discovered to be inherent to this interface without cycling. During in situ charging, spectroscopic characterization revealed that this interfacial layer evolved to form highly oxidized Co ions species along with lithium oxide and lithium peroxide species. Here, these findings suggest that the mechanism of interfacial impedance at the LiCoO2/LiPON interface is caused by chemical changes rather than space charge effects. Insights gained from this technique will shed light on important challenges of interfaces in all-solid-state energy storage and conversion systems and facilitate improved engineering of devices operated far from equilibrium.

  6. Macro- and microscopic in-situ observation of gas bubbles and sludge particles in a biogas tower reactor.

    PubMed

    Pietsch, Torsten; Mehrwald, Ralf; Grajetzki, Ralf; Sens, Jan; Pakendorf, Tim; Ulrich, Reinhard; Kumpart, Jörn; Matz, Gerhard; Märkl, Herbert

    2002-06-01

    Macroscopic and microscopic in-situ observation of particles and gas bubbles are used to get precise impressions of the hydrodynamical characteristics of a biologically active suspension. Moreover, values of in-situ velocities and particle densities can be gained by using these methods. The suspended anaerobic sludge revealed an extensive fibrous structure ('fur') on its surface. The observed microfibers have a profound influence on the settling/flotation behavior of the particles because they increase the effective particle volume, they may trap gas bubbles and they favor agglomeration. The biomass particles do not appear as single spherical objects but due to its fibrous structure on the outside as strongly interacting mass. The compressibility of the bubbles which are entrapped in the sludge agglomerates results in a pressure-dependent density of the sludge particles.

  7. Fusion of mobile in situ and satellite remote sensing observations of chemical release emissions to improve disaster response

    SciTech Connect

    Leifer, Ira; Melton, Christopher; Frash, Jason; Fischer, Marc L.; Cui, Xinguang; Murray, John J.; Green, David S.

    2016-09-22

    Chemical release disasters have serious consequences, disrupting ecosystems, society, and causing significant loss of life. Mitigating the destructive impacts relies on identification and mapping, monitoring, and trajectory forecasting. Improvements in sensor capabilities are enabling airborne and space-based remote sensing to support response activities. Key applications are improving transport models in complex terrain and improved disaster response. Understanding urban atmospheric transport in the Los Angeles Basin, where topographic influences on transport patterns are significant, was improved by leveraging the Aliso Canyon leak as an atmospheric tracer. Plume characterization data was collected by the AutoMObile trace Gas (AMOG) Surveyor, a commuter car modified for science. Mobile surface in situ CH4 and winds were measured by AMOG Surveyor under Santa Ana conditions to estimate an emission rate of 365±30% Gg yr-1. Vertical profiles were collected by AMOG Surveyor by leveraging local topography for vertical profiling to identify the planetary boundary layer at ~700 m. Topography significantly constrained plume dispersion by up to a factor of two. The observed plume trajectory was used to validate satellite aerosol optical depth-inferred atmospheric transport, which suggested the plume first was driven offshore, but then veered back towards land. Numerical long-range transport model predictions confirm this interpretation. Lastly, this study demonstrated a novel application of satellite aerosol remote sensing for disaster response.

  8. LOCAL AIR: Local Aerosol monitoring combining in-situ and Remote Sensing observations

    NASA Astrophysics Data System (ADS)

    Mona, Lucia; Caggiano, Rosa; Donvito, Angelo; Giannini, Vincenzo; Papagiannopoulos, Nikolaos; Sarli, Valentina; Trippetta, Serena

    2015-04-01

    The atmospheric aerosols have effects on climate, environment and health. Although the importance of the study of aerosols is well recognized, the current knowledge of the characteristics and their distribution is still insufficient, and there are large uncertainties in the current understanding of the role of aerosols on climate and the environment, both on a regional and local level. Overcoming these uncertainties requires a search strategy that integrates data from multiple platforms (eg, terrestrial, satellite, ships and planes) and the different acquisition techniques (for example, in situ measurements, remote sensing, modeling numerical and data assimilation) (Yu et al., 2006). To this end, in recent years, there have been many efforts such as the creation of networks dedicated to systematic observation of aerosols (eg, European Monitoring and Evaluation Programme-EMEP, European Aerosol Research Lidar NETwork-EARLINET, MicroPulse Lidar Network- MPLNET, and Aerosol Robotic NETwork-AERONET), the development and implementation of new satellite sensors and improvement of numerical models. The recent availability of numerous data to the ground, columnar and profiles of aerosols allows to investigate these aspects. An integrated approach between these different techniques could be able to provide additional information, providing greater insight into the properties of aerosols and their distribution and overcoming the limits of each single technique. In fact, the ground measurements allow direct determination of the physico-chemical properties of aerosols, but cannot be considered representative for large spatial and temporal scales and do not provide any information about the vertical profile of aerosols. On the other hand, the remote sensing techniques from the ground and satellite provide information on the vertical distribution of atmospheric aerosols both in the Planetary Boundary Layer (PBL), mainly characterized by the presence of aerosols originating from

  9. Continental hydrology from satellite multi-sensor data and in situ observations

    NASA Astrophysics Data System (ADS)

    Kouraev, A. V.

    2009-04-01

    freshwater input into the Arabian Gulf, affecting fishery, marine biology and biogeochemistry. ET basin is shared by several countries and is extensively used for irrigation and other types for water consumption. Cascades of large reservoirs are constructed in each of the four countries. Information on hydrological regime of the ET basin (water level in the reservoirs, amount of diverted water, river level and discharge) has paramount importance for studies of natural and anthropogenic influence on ET river system, and freshwater input into the Arabian Gulf. We present the results of studies for these two regions basing on our existing experience of using in situ data together with remote sensing techniques such as radar altimetry (TOPEX/Poseidon, Jason-1, GFO, ENVISAT), radiometry (SMMR, SSM/I), optical data (MODIS, Landsat) and space gravimetry data (GRACE). We analyse several parameters: a) water level in reservoirs and wetlands, b) river level and river discharge, c) water abundance and flooded area extent, and d) snow and ice cover (for Western Siberia). Research has been done in the framework of the Russian-French cooperation GDRI CAR-WET-SIB, French ANR IMPACT-Boreal project, and SMOS AO No. 4648.

  10. In situ observation of fractal growth during a-Si crystallization in a Cu3Si matrix

    NASA Astrophysics Data System (ADS)

    Russell, S. W.; Li, Jian; Mayer, J. W.

    1991-11-01

    We observe that the crystallization of amorphous Si thin films in contact with a copper silicide layer occurs at a temperature of around 485 °C in the form of dendrites with a fractal dimension of 1.7. The in situ observation of both the silicidation reaction, forming Cu3Si, and the subsequent crystallization of the remaining amorphous silicon in the silicide matrix, were observed during annealing in a transmission electron microscope. We estimate the radial growth rate of these crystallites at 5 nm/s at this temperature. The fractal dimension of the dendrites indicates a growth process similar to one known as diffusion-limited aggregation.

  11. Prediction of Geomagnetic Storm Strength from Inner Heliospheric In Situ Observations

    NASA Astrophysics Data System (ADS)

    Kubicka, M.; Moestl, C.; Rollett, T.; Feng, L.; Eastwood, J. P.; Boakes, P. D.

    2015-12-01

    In order to predict the effects of interplanetary coronal mass ejections (ICMEs) on Earth, it is important to know the properties of the interplanetary magnetic field (IMF). Of special interest is the southward component (Bz) of the IMF, acting as a main driver for geomagnetic storms. We are working on a proof-of-concept for predicting the strength of geomagnetic storms caused by ICMEs by using in situ data from spacecraft in the inner heliosphere. Our prediction includes the arrival time and speed of the ICME at Earth, the IMF's Bz component and the resulting disturbance storm time index (Dst), which is a prime indicator of geomagnetic activity. For Dst forecasting, the two well established models Burton et al. (1975) and O'Brien & McPherron (2000) are used. Necessary parameters for those models are the ICME speed and the Bz component of the IMF at 1 AU. We obtain the ICME speed using a drag-based model, and the IMF's Bz component is predicted based on a power law from the in situ data. Additionally, the ENLIL/WSA model provides the solar wind background speed for the drag-based model.An advantage of our method is the use of the in situ spacecraft as a reference point for the drag based-model, leading to a more precise arrival speed of the ICME at Earth, and an improved arrival time. Investigation of an ICME in June 2012 shows already very promising results for the Dst index, as well as for the ICME arrival speed. The main advantage of this method is the prediction lead time of ~21 hours compared to only ~40-60 minutes, using an L1 located spacecraft. Furthermore, the feasibility of this method can be studied with any in situ spacecraft temporarily located between the Sun and Earth, like Helios, Solar Orbiter or Solar Probe Plus, and also works for radial spacecraft alignments. The techniques we develop could be routinely applied to a mission that forms an artificial Lagrange point along the Sun-Earth line, e.g. for a Sunjammer or Heliostorm mission.

  12. In situ microscopic observation of chitin and fungal cells with chitinous cell walls in hydrothermal conditions

    PubMed Central

    Deguchi, Shigeru; Tsujii, Kaoru; Horikoshi, Koki

    2015-01-01

    Recent findings of intact chitin in fossil records suggest surprisingly high recalcitrance of this biopolymer during hydrothermal treatments. We also know in the experience of everyday life that mushroom, cells of which have chitinous cell walls, do not fall apart however long they are simmered. We used in situ optical microscopy to examine chitin and fungal cells with chitinous cell walls during hydrothermal treatments, and obtained direct evidence that they remained undegraded at temperatures well over 200 °C. The results show very hot and compressed water is needed to make mushrooms mushy. PMID:26148792

  13. In situ observation of ErD2 formation during D-2 loading via neutron diffraction

    SciTech Connect

    Browning, Jim; Snow, Clark; Wixom, Ryan R; Llobet, Anna; Rodriguez, Mark

    2011-01-01

    In an effort to better understand the structural changes occurring during hydrogen loading of erbium target materials, we have performed in situ D{sub 2} loading of erbium metal (powder) at temperature (450 C) with simultaneous neutron diffraction analysis. This experiment tracked the conversion of Er metal to the {alpha} erbium deuteride (solid-solution) phase and then into the {beta} (fluorite) phase. Complete conversion to ErD{sub 2.0} was accomplished at 10 Torr D{sub 2} pressure with deuterium fully occupying the tetrahedral sites in the fluorite lattice.

  14. Direct observation of Lomer-Cottrell locks during strain hardening in nanocrystalline nickel by in situ TEM.

    PubMed

    Lee, Joon Hwan; Holland, Troy B; Mukherjee, Amiya K; Zhang, Xinghang; Wang, Haiyan

    2013-01-01

    Strain hardening capability is critical for metallic materials to achieve high ductility during plastic deformation. A majority of nanocrystalline metals, however, have inherently low work hardening capability with few exceptions. Interpretations on work hardening mechanisms in nanocrystalline metals are still controversial due to the lack of in situ experimental evidence. Here we report, by using an in situ transmission electron microscope nanoindentation tool, the direct observation of dynamic work hardening event in nanocrystalline nickel. During strain hardening stage, abundant Lomer-Cottrell (L-C) locks formed both within nanograins and against twin boundaries. Two major mechanisms were identified during interactions between L-C locks and twin boundaries. Quantitative nanoindentation experiments recorded show an increase of yield strength from 1.64 to 2.29 GPa during multiple loading-unloading cycles. This study provides both the evidence to explain the roots of work hardening at small length scales and the insight for future design of ductile nanocrystalline metals.

  15. Variability and budget of CO2 in Europe: analysis of the CAATER airborne campaigns - Part 1: Observed variability

    NASA Astrophysics Data System (ADS)

    Xueref-Remy, I.; Messager, C.; Filippi, D.; Nedelec, P.; Ramonet, M.; Paris, J. D.; Ciais, P.

    2010-02-01

    Atmospheric airborne measurements of CO2 are very well-suited to estimate the time varying distribution of carbon sources and sinks at the regional scale. We present here an analysis of two cross-European airborne campaigns that have been carried out on 23-26 May 2001 (CAATER 1) and 2-3 October 2002 (CAATER 2) over Western Europe. The area covered during CAATER 1 (respectively CAATER 2) was comprised between longitude 4° W to 14° E and latitude 44° N to 52° N (respectively longitude 1° E to 17° E and latitude 46° N to 52° N). High precision in-situ CO2, CO and Radon 222 measurements have been recorded. Flasks samples have been collected during both campaigns to cross-validate the in-situ data. During CAATER 1 (respectively CAATER 2), the mean CO2 concentration was 370.1±4 ppm (respectively 371.7±5 ppm). A HYSPLIT backtrajectories analysis shows that during CAATER 1, dominant winds were blowing from the north-west. In the planetary boundary layer (PBL) airmasses got contaminated over Benelux and Western Germany by pollution from these high urbanized areas, reaching about 380 ppm. Air masses passing over rural areas are depleted in CO2 because of the photosynthesis activity of the land cover vegetation, as low as 355 ppm. During CAATER 2, the backtrajectory analysis shows that airmasses were distributed among the 4 sectors. Airmasses got enriched in CO2 and CO when passing above polluted spots in Germany but also in Poland, as these countries are known to hold part of the most polluting plants based on coal consumption, the so-called "dirty thirty" from WWF. Simultaneous measurements of in-situ CO2 and CO combined to backtrajectories helped us to discriminate the role of fossil fuel emissions from over CO2 sources. The ΔCO/ΔCO2 ratios (R2=0.33 to 0.88, slopes=2.42 to 10.37), calculated for polluted airmasses originating from different countries/regions, matched quite well national inventories, showing that the airborne measurements can help to identify

  16. Airborne lidar observations in the wintertime Arctic stratosphere - Polar stratospheric clouds

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Ismail, S.; Carter, A. F.; Higdon, N. S.; Butler, C. F.; Robinette, P. A.; Toon, O. B.; Schoeberl, M. R.

    1990-01-01

    Polar stratospheric cloud (PSC) distributions in the wintertime Arctic stratosphere and their optical characteristics were measured with a multiwavelength airborne lidar system as part of the 1989 Airborne Arctic Stratospheric Expedition. PSCs were observed on 10 flights between January 6 and February 2, 1989, into the polar vortex. The PSCs were found in the 14-27 km altitude range in regions where the temperatures were less than 195 K. Two types of aerosols with different optical characteristics (Types 1a and 1b) were observed in PSCs thought to be composed of nitric acid trihydrate. Water ice PSCs (Type 2) were observed to have high scattering ratios (greater than 10) and high aerosol depolarizations (greater than 10 percent) at temperatures less than 190 K.

  17. High-latitude E Region Ionosphere-thermosphere Coupling: A Comparative Study Using in Situ and Incoherent Scatter Radar Observations

    NASA Technical Reports Server (NTRS)

    Burchill, J. K.; Clemmons, J. H.; Knudsen, D. J.; Larsen, M.; Nicolls, M. J.; Pfaff, R. F.; Rowland, D.; Sangalli, L.

    2012-01-01

    We present in situ and ground-based measurements of the ratio k of ion cyclotronangular frequency to ion-neutral momentum transfer collision frequency to investigateionosphere-thermosphere (IT) coupling in the auroral E region. In situ observations were obtained by NASA sounding rocket 36.234, which was launched into the nightsideE region ionosphere at 1229 UT on 19 January 2007 from Poker Flat, AK. The payload carried instrumentation to determine ion drift angle and electric field vectors. Neutral winds were measured by triangulating a chemical tracer released from rocket 41.064 launched two minutes later. k is calculated from the rotation of the ion drift angle relative to the E-cross-B drift direction in a frame co-rotating with the payload. Between the altitudes of 118 km and 130 km k increases exponentially with a scale height of 9.3 +/- 0.7 km, deviating from an exponential above 130 km. k = 1 at an altitude z(sub0) of 119.9 +/- 0.5 km. The ratio was also estimated from Poker Flat Incoherent Scatter Radar (PFISR) measurements using the rotation of ion velocity with altitude. Exponential fits to the PFISR measurements made during the flight of 41.064 yield z(sub0) 115.9 +/- 1.2 km and a scale height of 9.1 +/- 1.0 km. Differences between in situ and ground-based measurements show that the E region atmospheric densities were structured vertically and/or horizontally on scales of 1 km to 10 km. There were no signs of ionospheric structure in ion density or ion temperature below scales of 1 km. The observations demonstrate the accuracy with which the in situ and PFISR data may be used as probes of IT coupling.

  18. Design and development of an environmental cell for dynamic in situ observation of gas-solid reactions at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Deshmukh, Pushkarraj Vasant

    In situ monitoring of events in transmission electron microscopy provides information on how materials behave in their true state while varying environmental conditions (i.e. temperature and pressure) and exposure to reactant gas mixtures. In-situ results are usually different from static, post-reaction observations because they provide valuable real time---rather than post mortem---information. To facilitate applications that demand in situ observations, a transmission electron microscope specimen holder assembly has been developed in this dissertation. This assembly incorporates a gas flow and heating mechanism along with a novel window-type environmental cell. A controlled mixture of up to four different gases can be circulated through the cell during an experiment. In addition, the specimen can be heated up to a temperature of 1500°C using a specially designed carbon dioxide laser mechanism. This heating technique provides major advantages over conventional methods in terms of product life, specimen heating time and design size. The cell design incorporates a gas reaction chamber less than 1 mm in height, enclosed between a pair of 20 nm thick silicon nitride windows. The chamber can accommodate a specimen or a grid having a diameter of 3 mm and thicknesses in the range of 50 to 100 microns. The volume for the gas environment within the chamber is approximately 3 mm 3 and the gas path length is less than 1 mm. This holder has been designed by incorporating cutting edge heating and Si3N4 window fabrication technology to achieve excellent resolution along with a low thermal drift. Successful application of the holder has been shown to provide scientists with an economical alternative to dedicated transmission electron microscopes for a vast array of in situ applications. These applications include understanding the basic material properties, catalysis reactions, semiconductor device development, and nano structure fabrication.

  19. Airborne Millimeter-Wave Radiometric Observations of Cirrus Clouds

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Racette, P.

    1997-01-01

    This paper reports the first radiometric measurements of cirrus clouds in the frequency range of 89-325 GHz from a high-altitude aircraft flight. The measurements are conducted with a Millimeter-wave Imaging Radiometer (MIR) on board the NASA ER-2 aircraft over a region in northern Oklahoma. Aboard the same aircraft are a cloud lidar system and a multichannel radiometer operating at the visible and infrared wavelengths. The instrument ensemble is well suited for identifying cirrus clouds. It is shown that the depressions in brightness temperatures associated with a few intense cirrus clouds occur at all frequency channels of the MIR. Estimates of total ice water path of the cirrus clouds are derived from comparisons of radiative transfer calculations and observed brightness depressions.

  20. Magnesium degradation observed in situ under flow by synchrotron radiation based microtomography

    NASA Astrophysics Data System (ADS)

    Feyerabend, Frank; Dose, Thomas; Xu, Yuling; Beckmann, Felix; Stekker, Michael; Willumeit-Römer, Regine; Schreyer, Andreas; Wilde, Fabian; Hammel, Jörg U.

    2016-10-01

    The use of degradable magnesium based implants is becoming clinically relevant, e.g. for the use as bone screws. Still there is a lack of analyzing techniques to characterize the in vitro degradation behavior of implant prototypes. The aim of this study was to design an in situ environment to continuously monitor the degradation processes under physiological conditions by time-lapse SRμCT. The use of physiological conditions was chosen to get a better approach to the in vivo situation, as it could be shown by many studies, that these conditions change on the one hand the degradation rate and on the other hand also the formed degradation products. The resulting in situ environment contains a closed bioreactor system to control and monitor the relevant parameters (37°C, 5 % O2, 20 % CO2) and to grant sterility of the setup. A flow cell was designed and manufactured from polyether etherketone (PEEK), which was chosen because of the good mechanical properties, high thermal and chemical resistance and radiographic translucency. Sterilization of the system including the sample was reached by a transient flush with 70 % ethanol and subsequent replacement by physiological medium (Modified Eagle Medium alpha). As proof of principle it could be shown that the system remained sterile during a beamtime of several days and that the continuous SRμCT imaging was feasible.

  1. Maintaining Situation Awareness with Autonomous Airborne Observation Platforms

    NASA Technical Reports Server (NTRS)

    Freed, Michael; Fitzgerald, Will

    2005-01-01

    Unmanned Aerial Vehicles (UAVs) offer tremendous potential as intelligence, surveillance and reconnaissance (ISR) platforms for early detection of security threats and for acquisition and maintenance of situation awareness in crisis conditions. However, using their capabilities effectively requires addressing a range of practical and theoretical problems. The paper will describe progress by the "Autonomous Rotorcraft Project," a collaborative effort between NASA and the U.S. Army to develop a practical, flexible capability for UAV-based ISR. Important facets of the project include optimization methods for allocating scarce aircraft resources to observe numerous, distinct sites of interest; intelligent flight automation software than integrates high-level plan generation capabilities with executive control, failure response and flight control functions; a system architecture supporting reconfiguration of onboard sensors to address different kinds of threats; and an advanced prototype vehicle designed to allow large-scale production at low cost. The paper will also address human interaction issues including an empirical method for determining how to allocate roles and responsibilities between flight automation and human operations.

  2. An Airborne Infrared Telescope and Spectrograph for Solar Eclipse Observations

    NASA Astrophysics Data System (ADS)

    DeLuca, Edward E.; Cheimets, Peter; Golub, Leon

    2014-06-01

    The solar infrared spectrum offers great possibilities for direct spatially resolved measurements of the solar coronal magnetic fields, via imaging of the plasma that is constrained to follow the magnetic field direction and via spectro-polarimetry that permits measurement of the field strength in the corona. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections (CME) and provides the ultimate source of energy for space weather. The large scale structure of the coronal field, and the opening up of the field in a transition zone between the closed and open corona determines the speed and structure of the solar wind, providing the background environment through which CMEs propagate. At present our only direct measurements of the solar magnetic fields are in the photosphere and chromosphere. The ability to determine where and why the corona transitions from closed to open, combined with measurements of the field strength via infrared coronal spectro-polarimetry will give us a powerful new tool in our quest to develop the next generation of forecasting models.We describe a first step in achieving this goal: a proposal for a new IR telescope, image stabilization system, and spectrometer, for the NCAR HIPER GV aircraft. The telescope/spectrograph will operate in the 2-6micron wavelength region, during solar eclipses, starting with the trans-north American eclipse in August 2017. The HIAPER aircraft flying at ~35,000 ft will provide an excellent platform for IR observations. Our imaging and spectroscopy experiment will show the distribution and intensity of IR forbidden lines in the solar corona.

  3. Observation of the controlled assembly of preclick components in the in situ click chemistry generation of a chitinase inhibitor.

    PubMed

    Hirose, Tomoyasu; Maita, Nobuo; Gouda, Hiroaki; Koseki, Jun; Yamamoto, Tsuyoshi; Sugawara, Akihiro; Nakano, Hirofumi; Hirono, Shuichi; Shiomi, Kazuro; Watanabe, Takeshi; Taniguchi, Hisaaki; Sharpless, K Barry; Omura, Satoshi; Sunazuka, Toshiaki

    2013-10-01

    The Huisgen cycloaddition of azides and alkynes, accelerated by target biomolecules, termed "in situ click chemistry," has been successfully exploited to discover highly potent enzyme inhibitors. We have previously reported a specific Serratia marcescens chitinase B (SmChiB)-templated syn-triazole inhibitor generated in situ from an azide-bearing inhibitor and an alkyne fragment. Several in situ click chemistry studies have been reported. Although some mechanistic evidence has been obtained, such as X-ray analysis of [protein]-["click ligand"] complexes, indicating that proteins act as both mold and template between unique pairs of azide and alkyne fragments, to date, observations have been based solely on "postclick" structural information. Here, we describe crystal structures of SmChiB complexed with an azide ligand and an O-allyl oxime fragment as a mimic of a click partner, revealing a mechanism for accelerating syn-triazole formation, which allows generation of its own distinct inhibitor. We have also performed density functional theory calculations based on the X-ray structure to explore the acceleration of the Huisgen cycloaddition by SmChiB. The density functional theory calculations reasonably support that SmChiB plays a role by the cage effect during the pretranslation and posttranslation states of selective syn-triazole click formation.

  4. In situ TEM observation of electrochemical lithiation of sulfur confined within inner cylindrical pores of carbon nanotubes

    DOE PAGES

    Kim, Hyea; Lee, Jung Tae; Magasinski, Alexandre; ...

    2015-10-26

    Lithium insertion into sulfur confined within 200 nm cylindrical inner pores of individual carbon nanotubes (CNTs) was monitored in-situ in a transmission electron microscope (TEM). This electrochemical reaction was initiated at one end of the S-filled CNTs. The material expansion during lithiation was accommodated by the expansion into the remaining empty pore volume and no fracture of the CNT walls was detected. A sharp interface between the initial and lithiated S was observed. The reaction front was flat, oriented perpendicular to the confined S cylinder and propagated along the cylinder length. Lithiation of S in the proximity of conductive carbonmore » proceeded at the same rate as the one in the center of the pore, suggesting the presence of electron pathways at the Li2S/S interface. Density of states (DOS) calculations further confirmed this hypothesis. In-situ electron diffraction showed a direct phase transformation of S into nanocrystalline Li2S without detectable formation of any intermediates, such as polysulfides and LiS. These important insights may elucidate some of the reaction mechanisms and guide the improvements in the design of C-S nanocomposites for high specific energy Li-S batteries. As a result, the proposed use of conductive CNTs with tunable pore diameter as cylindrical reaction vessels for in-situ TEM studies of electrochemical reactions proved to be highly advantageous and may help to resolve the on-going problems in battery technology.« less

  5. Analysis of motor vehicle emissions over eastern Los Angeles, California from in-situ airborne measurements of trace gases and particulates during CalNex

    NASA Astrophysics Data System (ADS)

    Pollack, I. B.; Ryerson, T. B.; Trainer, M.; Frost, G. J.; Holloway, J. S.; McKeen, S. A.; Peischl, J.; Fahey, D. W.; Perring, A.; Schwarz, J. P.; Spackman, J. R.

    2010-12-01

    In-situ measurements of trace gases and particulates were acquired on the instrumented NOAA WP-3D aircraft during the CalNex (California Research at the Nexus of Air Quality and Climate Change) field study in May and June 2010. Multiple daytime research flights under similar meteorological conditions provide a sufficient data set for characterizing automobile emissions over the eastern Los Angeles (eLA) area of the South Coast air basin. Ratios of nitrogen oxides (NOx) and black carbon (BC) to carbon monoxide (CO) are used to isolate emissions of light duty vehicles from those of medium/heavy duty diesel trucks. Observations in the mixed boundary layer for the eLA area are separated according to latitude, longitude, and altitude. Industrial influences are eliminated by filtering the data according to SO2 mixing ratio and wind direction. The resulting correlations show weekday-to-weekend differences in enhancement ratios of NOx to CO and BC to CO, indicating a general tendency for higher emissions from heavy duty vehicles during the week. The CalNex data over eLA in 2010 will be compared to eLA data from a research flight in May 2002 by the WP-3D aircraft during the Intercontinental Transport and Chemical Transformation (ITCT) field study.

  6. In situ observation of heat-induced degradation of perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Divitini, G.; Cacovich, S.; Matteocci, F.; Cinà, L.; di Carlo, A.; Ducati, C.

    2016-02-01

    The lack of thermal stability of perovskite solar cells is hindering the progress of this technology towards adoption in the consumer market. Different pathways of thermal degradation are activated at different temperatures in these complex nanostructured hybrid composites. Thus, it is essential to explore the thermal response of the mesosuperstructured composite device to engineer materials and operating protocols. Here we produce devices according to four well-established recipes, and characterize their photovoltaic performance as they are heated within the operational range. The devices are analysed using transmission electron microscopy as they are further heated in situ, to monitor changes in morphology and chemical composition. We identify mechanisms for structural and chemical changes, such as iodine and lead migration, which appear to be correlated to the synthesis conditions. In particular, we identify a correlation between exposure of the perovskite layer to air during processing and elemental diffusion during thermal treatment.

  7. Strength, Hardening, and Failure Observed by In Situ TEM Tensile Testing.

    PubMed

    Kiener, Daniel; Kaufmann, Petra; Minor, Andrew M

    2012-11-01

    We present in situ transmission electron microscope tensile tests on focused ion beam fabricated single and multiple slip oriented Cu tensile samples with thicknesses in the range of 100-200 nm. Both crystal orientations fail by localized shear. While failure occurs after a few percent plastic strain and limited hardening in the single slip case, the multiple slip samples exhibit extended homogenous deformation and necking due to the activation of multiple dislocation sources in conjunction with significant hardening. The hardening behavior at 1% plastic strain is even more pronounced compared to compression samples of the same orientation due to the absence of sample taper and the interface to the compression platen. Moreover, we show for the first time that the strain rate sensitivity of such FIB prepared samples is an order of magnitude higher than that of bulk Cu.

  8. In situ observation of deformation processes in nanocrystalline face-centered cubic metals

    PubMed Central

    Kobler, Aaron; Brandl, Christian; Hahn, Horst

    2016-01-01

    Summary The atomistic mechanisms active during plastic deformation of nanocrystalline metals are still a subject of controversy. The recently developed approach of combining automated crystal orientation mapping (ACOM) and in situ straining inside a transmission electron microscope was applied to study the deformation of nanocrystalline PdxAu1− x thin films. This combination enables direct imaging of simultaneously occurring plastic deformation processes in one experiment, such as grain boundary motion, twin activity and grain rotation. Large-angle grain rotations with ≈39° and ≈60° occur and can be related to twin formation, twin migration and twin–twin interaction as a result of partial dislocation activity. Furthermore, plastic deformation in nanocrystalline thin films was found to be partially reversible upon rupture of the film. In conclusion, conventional deformation mechanisms are still active in nanocrystalline metals but with different weighting as compared with conventional materials with coarser grains. PMID:27335747

  9. In situ atomic-scale observation of continuous and reversible lattice deformation beyond the elastic limit

    PubMed Central

    Wang, Lihua; Liu, Pan; Guan, Pengfei; Yang, Mingjie; Sun, Jialin; Cheng, Yongqiang; Hirata, Akihiko; Zhang, Ze; Ma, Evan; Chen, Mingwei; Han, Xiaodong

    2013-01-01

    The elastic strain sustainable in crystal lattices is usually limited by the onset of inelastic yielding mediated by discrete dislocation activity, displacive deformation twinning and stress-induced phase transformations, or fracture associated with flaws. Here we report a continuous and gradual lattice deformation in bending nickel nanowires to a reversible shear strain as high as 34.6%, which is approximately four times that of the theoretical elastic strain limit for unconstrained loading. The functioning deformation mechanism was revealed on the atomic scale by an in situ nanowire bending experiments inside a transmission electron microscope. The complete continuous lattice straining process of crystals has been witnessed in its entirety for the straining path, which starts from the face-centred cubic lattice, transitions through the orthogonal path to reach a body-centred tetragonal structure and finally to a re-oriented face-centred cubic structure. PMID:24022231

  10. In situ observation and measurement of composites subjected to extremely high temperature

    NASA Astrophysics Data System (ADS)

    Fang, Xufei; Yu, Helong; Zhang, Guobing; Su, Hengqiang; Tang, Hongxiang; Feng, Xue

    2014-03-01

    In this work, we develop an instrument to study the ablation and oxidation process of materials such as C/SiC (carbon fiber reinforced silicon carbide composites) and ultra-high temperature ceramic in extremely high temperature environment. The instrument is integrated with high speed cameras with filtering lens, infrared thermometers and water vapor generator for image capture, temperature measurement, and humid atmosphere, respectively. The ablation process and thermal shock as well as the temperature on both sides of the specimen can be in situ monitored. The results show clearly the dynamic ablation and liquid oxide flowing. In addition, we develop an algorithm for the post-processing of the captured images to obtain the deformation of the specimens, in order to better understand the behavior of the specimen subjected to high temperature.

  11. In situ observation of deformation processes in nanocrystalline face-centered cubic metals.

    PubMed

    Kobler, Aaron; Brandl, Christian; Hahn, Horst; Kübel, Christian

    2016-01-01

    The atomistic mechanisms active during plastic deformation of nanocrystalline metals are still a subject of controversy. The recently developed approach of combining automated crystal orientation mapping (ACOM) and in situ straining inside a transmission electron microscope was applied to study the deformation of nanocrystalline Pd x Au1- x thin films. This combination enables direct imaging of simultaneously occurring plastic deformation processes in one experiment, such as grain boundary motion, twin activity and grain rotation. Large-angle grain rotations with ≈39° and ≈60° occur and can be related to twin formation, twin migration and twin-twin interaction as a result of partial dislocation activity. Furthermore, plastic deformation in nanocrystalline thin films was found to be partially reversible upon rupture of the film. In conclusion, conventional deformation mechanisms are still active in nanocrystalline metals but with different weighting as compared with conventional materials with coarser grains.

  12. In situ observations of the isotopic composition of methane at the Cabauw tall tower site

    NASA Astrophysics Data System (ADS)

    Röckmann, Thomas; Eyer, Simon; van der Veen, Carina; Popa, Maria E.; Tuzson, Béla; Monteil, Guillaume; Houweling, Sander; Harris, Eliza; Brunner, Dominik; Fischer, Hubertus; Zazzeri, Giulia; Lowry, David; Nisbet, Euan G.; Brand, Willi A.; Necki, Jaroslav M.; Emmenegger, Lukas; Mohn, Joachim

    2016-08-01

    High-precision analyses of the isotopic composition of methane in ambient air can potentially be used to discriminate between different source categories. Due to the complexity of isotope ratio measurements, such analyses have generally been performed in the laboratory on air samples collected in the field. This poses a limitation on the temporal resolution at which the isotopic composition can be monitored with reasonable logistical effort. Here we present the performance of a dual isotope ratio mass spectrometric system (IRMS) and a quantum cascade laser absorption spectroscopy (QCLAS)-based technique for in situ analysis of the isotopic composition of methane under field conditions. Both systems were deployed at the Cabauw Experimental Site for Atmospheric Research (CESAR) in the Netherlands and performed in situ, high-frequency (approx. hourly) measurements for a period of more than 5 months. The IRMS and QCLAS instruments were in excellent agreement with a slight systematic offset of (+0.25 ± 0.04) ‰ for δ13C and (-4.3 ± 0.4) ‰ for δD. This was corrected for, yielding a combined dataset with more than 2500 measurements of both δ13C and δD. The high-precision and high-temporal-resolution dataset not only reveals the overwhelming contribution of isotopically depleted agricultural CH4 emissions from ruminants at the Cabauw site but also allows the identification of specific events with elevated contributions from more enriched sources such as natural gas and landfills. The final dataset was compared to model calculations using the global model TM5 and the mesoscale model FLEXPART-COSMO. The results of both models agree better with the measurements when the TNO-MACC emission inventory is used in the models than when the EDGAR inventory is used. This suggests that high-resolution isotope measurements have the potential to further constrain the methane budget when they are performed at multiple sites that are representative for the entire European domain.

  13. Height-resolved Scaling Properties of Water Vapor in the Mesoscale using Airborne Lidar Observations

    NASA Astrophysics Data System (ADS)

    Fischer, L.; Craig, G. C.; Kiemle, C.

    2012-12-01

    Free tropospheric water vapor variability, measured by long-range airborne differential-absorption lidar, has been analyzed by using structure functions of different orders at altitudes from 2 to 10 km. It is shown that the water vapor field exhibits scale invariance at spatial scales ranging from 5km to 100km, where scaling behavior is defined as a power law dependence of structure functions on length scale. In contrast to one-dimensional in situ measurements, two-dimensional water vapor lidar observations allow height-resolved analysis of scaling exponents with a vertical resolution of 200m. Using this data a clear distinction was found between scaling properties above and below an air-mass boundary. Data has been analysed from three campaigns, COPS/ETReC (2007) collected during summertime in middle and south Europe, T-PARC (2008) collected during late summer around Japan mostly over sea and T-IPY (2008) collected during winter around Spitsbergen mostly over sea. After discarding flights with low lidar signals or large data gaps, and after horizontal averaging to a resolution of 1-5km to obtain a high signal to noise ratio, structure functions were computed for 20 flights at various heights with a total length of more than 300,000 km. Scaling exponents were obtained for structure functions up to fifth order, and results will be presented for first and second order structure functions and for intermittency (variation of the scaling exponent with increasing order). The scaling exponents show no significant latitudinal, seasonal and land/sea dependence, but show significantly different behavior depending on whether the time series occured in an air mass influenced by cumulus convection or not. A classification of the time series into two groups according to whether the series occurred above or below the level of nearby convective cloud tops was performed by detecting the cloud height from the lidar backscatter signal of the corresponding flight. It was found that

  14. Height-resolved Scaling Properties of Tropospheric Water Vapour based on Airborne Lidar Observations

    NASA Astrophysics Data System (ADS)

    Kiemle, Christoph; Fischer, Lucas; Craig, George C.

    2013-04-01

    Two-dimensional vertical water vapour cross sections of the free troposphere between altitudes of 2 and 10 km, measured by nadir-viewing airborne differential-absorption lidar with high spatial resolution, were analyzed using structure functions up to the fifth order. We found scale invariance, i.e. a power-law dependency of structure function on length scale, for scales between 5 and 100 km, for the horizontal time series of water vapour mixing ratio. In contrast to one-dimensional in situ measurements, the two-dimensional water vapor lidar observations allow height-resolved analyses of power-law scaling exponents at a vertical resolution of 200 m. The data reveal significantly different scaling properties above and below an air-mass boundary. They stem from three very dissimilar aircraft campaigns: COPS/ETReC over middle and southern Europe in summer 2007, T-PARC around Japan mostly over sea in late summer 2008, and T-IPY around Spitsbergen over sea in winter 2008. After discarding flight segments with low lidar signals or large data gaps, and after averaging horizontally to a resolution of between 1 and 5 km to obtain a high signal to noise ratio, structure functions were computed for 20 flights at various heights, adding up to a length of more than 300,000 km. The power-law scaling exponents of the structure functions do not show significant latitudinal, seasonal or land/sea dependency, but they do differ between air masses influenced by moist convection and air masses aloft, not influenced. A classification of the horizontal water vapour time series into two groups according to whether the series occurred above or below the level of nearby convective cloud tops could be performed by detecting the cloud top height from the lidar backscatter signal in the corresponding flight segment. We found that the scaling exponents can be divided into two groups depending on the respective air mass: The smoothness of the time series, expressed by the first-order scaling

  15. The Sodankylä in situ soil moisture observation network: an example application of ESA CCI soil moisture product evaluation

    NASA Astrophysics Data System (ADS)

    Ikonen, Jaakko; Vehviläinen, Juho; Rautiainen, Kimmo; Smolander, Tuomo; Lemmetyinen, Juha; Bircher, Simone; Pulliainen, Jouni

    2016-04-01

    During the last decade there has been considerable development in remote sensing techniques relating to soil moisture retrievals over large areas. Within the framework of the European Space Agency's (ESA) Climate Change Initiative (CCI) a new soil moisture product has been generated, merging different satellite-based surface soil moisture based products. Such remotely sensed data need to be validated by means of in situ observations in different climatic regions. In that context, a comprehensive, distributed network of in situ measurement stations gathering information on soil moisture, as well as soil temperature, has been set up in recent years at the Finnish Meteorological Institute's (FMI) Sodankylä Arctic research station. The network forms a calibration and validation (CAL-VAL) reference site and is used as a tool to evaluate the validity of satellite retrievals of soil properties. In this paper we present the Sodankylä CAL-VAL reference site soil moisture observation network, its instrumentation as well as its areal representativeness over the study area and the region in general as a whole. As an example of data utilization, comparisons of spatially weighted average top-layer soil moisture observations between the years 2012 and 2014 against ESA CCI soil moisture data product estimates are presented and discussed. The comparisons were made against a single ESA CCI data product pixel encapsulating most of the Sodankylä CAL-VAL network sites. Comparisons are made with daily averaged and running weekly averaged soil moisture data as well as through application of an exponential soil moisture filter. The overall achieved correlation between the ESA CCI data product and in situ observations varies considerably (from 0.479 to 0.637) depending on the applied comparison perspective. Similarly, depending on the comparison perspective used, inter-annual correlation comparison results exhibit even more pronounced variation, ranging from 0.166 to 0.840.

  16. Case Studies for UV, O2-A Band and Polarimetric Airborne Remote Sensing Observations of Coastal Waters: Implications for Atmospheric Correction.

    NASA Astrophysics Data System (ADS)

    Chowdhary, J.; van Diedenhoven, B.; Knobelspiesse, K. D.; Cairns, B.; Wasilewski, A. P.; Mccubbin, I. B.

    2014-12-01

    A major challenge for spaceborne observations of ocean color is to correct for atmospheric scattering, which typically contributes ≥85% to the top-of-atmosphere (TOA) radiance and varies substantially with aerosols. Ocean color missions traditionally analyze TOA radiance in the near-infrared (NIR), where the ocean is black, to constrain the TOA atmospheric scattering in the visible (VIS). However, this procedure is limited by insufficient sensitivity of NIR radiance to absorption and vertical distribution of aerosols, and by uncertainties in the extrapolation of aerosol properties from the NIR to the VIS. To improve atmospheric correction for ocean color observations, one needs to change the traditional procedure for this correction and/or increase the aerosol information. The instruments proposed for the Pre-Aerosol, Clouds, and ocean Ecosystem (PACE) mission include ultraviolet and Oxygen A-band observations, as well as multispectral and multiangle polarimetry, to increase the aerosol information content. However no studies have been performed on whether such observations contain sufficient aerosol information, and on how to use this information, to substantially improve atmospheric correction. To study the atmospheric correction capabilities of PACE-like instruments, we are conducting field experiments off the Coast of California to obtain high-altitude airborne and in-situ observations of water-leaving radiance. The airborne data sets consist of hyperspectral radiance between 380-2500 nm by the Airborne Visible/Infrared Imaging Spectrometer, and narrow-band multiangle polarimetric data between 410-2250 nm by the Research Scanning Polarimeter. We discuss the quality of and comparisons between these data sets, and their differential sensitivities to variations in aerosol properties and ocean color.

  17. Biooptical variability in the Greenland Sea observed with the Multispectral Airborne Radiometer System (MARS)

    NASA Technical Reports Server (NTRS)

    Mueller, James L.; Trees, Charles C.

    1989-01-01

    A site-specific ocean color remote sensing algorithm was developed and used to convert Multispectral Airborne Radiometer System (MARS) spectral radiance measurements to chlorophyll-a concentration profiles along aircraft tracklines in the Greenland Sea. The analysis is described and the results given in graphical or tabular form. Section 2 describes the salient characteristics and history of development of the MARS instrument. Section 3 describes the analyses of MARS flight segments over consolidated sea ice, resulting in a set of altitude dependent ratios used (over water) to estimate radiance reflected by the surface and atmosphere from total radiance measured. Section 4 presents optically weighted pigment concentrations calculated from profile data, and spectral reflectances measured in situ from the top meter of the water column; this data was analyzed to develop an algorithm relating chlorophyll-a concentrations to the ratio of radiance reflectances at 441 and 550 nm (with a selection of coefficients dependent upon whether significant gelvin presence is implied by a low ratio of reflectances at 410 and 550 nm). Section 5 describes the scaling adjustments which were derived to reconcile the MARS upwelled radiance ratios at 410:550 nm and 441:550 nm to in situ reflectance ratios measured simultaneously on the surface. Section 6 graphically presents the locations of MARS data tracklines and positions of the surface monitoring R/V. Section 7 presents stick-plots of MARS tracklines selected to illustrate two-dimensional spatial variability within the box covered by each day's flight. Section 8 presents curves of chlorophyll-a concentration profiles derived from MARS data along survey tracklines. Significant results are summarized in Section 1.

  18. Impact of Deep Convection on UTLS Composition -New Observations from Recent Airborne Field Studies

    NASA Astrophysics Data System (ADS)

    Pan, L.

    2014-12-01

    Deep convection redistributes chemical trace gas species throughout the troposphere. Tropopause-penetrating deep convection injects water vapor and pollutants into the lower stratosphere. To obtain the necessary information for characterizing its role in chemistry-climate coupling, the impact of deep convection on UTLS ozone, water vapor, and short-lived organic species has been a key component of several recent airborne field campaigns. We present selected findings and observational highlights from two airborne field campaigns. They are the CONvective TRansport of Active Species in the Tropics (CONTRAST) experiment, conducted January-February 2014 over the western Pacific using the NCAR GV research aircraft, in collaboration with the UK FAAM BAe146 and the NASA Global Hawk, and the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) experiment, conducted August-September 2013 over the north America using the NASA DC-8 and ER-2 research aircraft.

  19. Integration of airborne altimetry and in situ radar measurements to estimate marine ice thickness beneath the Larsen C ice shelf, Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    McGrath, D.; Steffen, K.; Rodriguez Lagos, J.

    2010-12-01

    Observed atmospheric and oceanic warming is driving significant retreat and / or collapse of ice shelves along the Antarctic Peninsula totaling over 25,000 km2 in the past five decades. Basal melting of meteoric ice can occur near the grounding line of deep glacier inflows if the ocean water is above the pressure melting point. Buoyant meltwater will develop thermohaline circulation, rising beneath the ice shelf, where it may become supercooled and subsequently refreeze in ice draft minima. Marine ice, due to its warm and thus relatively viscous nature, is hypothesized to suture parallel flow bands, increasing ice shelf stability by arresting fracture propagation and controlling iceberg calving dimensions. Thus efforts to model ice shelf stability require accurate estimates of marine ice location and thickness. Ice thickness of a floating ice shelf can be determined in two manners: (1) from measurements of ice elevation above sea level and the calculation of ice thickness from assumptions of hydrostatic equilibrium, and (2) from radar echo measurements of the ice-water interface. Marine ice can confound the latter because its high dielectric constant and strong absorptive properties attenuate the radar energy, often preventing a return signal from the bottom of the ice shelf. These two methods are complementary for determining the marine ice component though because positive anomalies in (1) relative to (2) suggest regions of marine ice accretion. Nearly 350 km of ice penetrating radar (25 MHz) surveys were collected on the Larsen C ice shelf, in conjunction with kinematic GPS measurements and collocated with surface elevation data from the NASA Airborne Topographic Mapper (ATM) as part of the ICE Bridge mission in 2009. Basal ice topography and total ice thickness is accurately mapped along the survey lines and compared with calculated ice thickness from both the kinematic GPS and ATM elevation data. Positive anomalies are discussed in light of visible imagery and

  20. A three-dimensional characterization of Arctic aerosols from airborne Sun photometer observations: PAM-ARCMIP, April 2009

    NASA Astrophysics Data System (ADS)

    Stone, R. S.; Herber, A.; Vitale, V.; Mazzola, M.; Lupi, A.; Schnell, R. C.; Dutton, E. G.; Liu, P. S. K.; Li, S.-M.; Dethloff, K.; Lampert, A.; Ritter, C.; Stock, M.; Neuber, R.; Maturilli, M.

    2010-07-01

    The Arctic climate is modulated, in part, by atmospheric aerosols that affect the distribution of radiant energy passing through the atmosphere. Aerosols affect the surface-atmosphere radiation balance directly through interactions with solar and terrestrial radiation and indirectly through interactions with cloud particles. Better quantification of the radiative forcing by different types of aerosol is needed to improve predictions of future climate. During April 2009, the airborne campaign Pan-Arctic Measurements and Arctic Regional Climate Model Inter-comparison Project (PAM-ARCMIP) was conducted. The mission was organized by Alfred Wegener Institute for Polar and Marine Research of Germany and utilized their research aircraft, Polar-5. The goal was to obtain a snapshot of surface and atmospheric conditions over the central Arctic prior to the onset of the melt season. Characterizing aerosols was one objective of the campaign. Standard Sun photometric procedures were adopted to quantify aerosol optical depth AOD, providing a three-dimensional view of the aerosol, which was primarily haze from anthropogenic sources. Independent, in situ measurements of particle size distribution and light extinction, derived from airborne lidar, are used to corroborate inferences made using the AOD results. During April 2009, from the European to the Alaskan Arctic, from sub-Arctic latitudes to near the pole, the atmosphere was variably hazy with total column AOD at 500 nm ranging from ˜0.12 to >0.35, values that are anomalously high compared with previous years. The haze, transported primarily from Eurasian industrial regions, was concentrated within and just above the surface-based temperature inversion layer. Extinction, as measured using an onboard lidar system, was also greatest at low levels, where particles tended to be slightly larger than at upper levels. Black carbon (BC) (soot) was observed at all levels sampled, but at moderate to low concentrations compared with

  1. In situ transmission electron microscopy observations of lithiation of spherical silicon nanopowder produced by induced plasma atomization

    NASA Astrophysics Data System (ADS)

    Leblanc, Dominic; Wang, Chongmin; He, Yang; Bélanger, Daniel; Zaghib, Karim

    2015-04-01

    Composite Li-ion anode can be fabricated using silicon nanopowders synthesized by induced plasma atomization. Properties of such nanopowder were characterized by physical and electrochemical methods. Primary particles were crystalline with spherical shape and the typical diameter ranging from 50 to 200 nm. The Si nanopowder showed a high gravimetric capacity (4900 mAh/g) at first discharge and around 12% irreversible loss of lithium. In addition, observations of a single silicon particle made by in situ TEM permitted to compare the volume change during lithiation with other silicon anode nanomaterials.

  2. In-situ TEM observation of dynamic interaction between dislocation and cavity in BCC metals in tensile deformation

    NASA Astrophysics Data System (ADS)

    Tougou, Kouichi; Shikata, Akihito; Kawase, Uchu; Onitsuka, Takashi; Fukumoto, Ken-ichi

    2015-10-01

    To investigate the effect of irradiation hardening of structural materials due to cavity formation in BCC metals for nuclear applications, an in-situ transmission electron microscopy (TEM) observation in tensile test was performed for the helium ion-irradiated specimens of pure molybdenum and pure iron. The obstacle barrier strength, α was calculated from the bow-out dislocation based on line tension model, and the obstacle barrier strengths of cavity in pure molybdenum and pure iron were about 0.5-0.7. The fractions of cross-slip generation of dislocation of screw type due to interaction with the cavities were about 16-18 % for pure molybdenum.

  3. Comparison of Arctic sea ice thickness and snow depth estimates from CFSR with in situ observations

    NASA Astrophysics Data System (ADS)

    Sato, Kazutoshi; Inoue, Jun

    2017-03-01

    Sea ice growth is modulated by snow cover, and understanding this relationship requires an accurate determination of snow depth. However, a lack of in situ measurements complicates understanding of the interaction of snow depth with sea ice growth. We evaluated the accuracy of Climate Forecast System Reanalysis (CFSR) data for snow depth and sea ice thickness to study the change of snow depth on Arctic sea ice. We compared CFSR and snow depth data from 35 drifting buoys in 2002-2013. The mean annual cycle of CFSR snow depth corresponded well with the buoy data. However, the CFSR data had a positive bias during winter (10-20 cm) and spring (5-25 cm), and a negative bias during summer (-25-0 cm) and autumn (-5-10 cm). The CFSR data showed increases in snow depth from 1979 to 2013 over the Beaufort and northern Chukchi Seas during November. Significant positive trends in precipitation contributed to increased snow depth in this region when sea ice began to form. The results of model experiments using a 1-D thermodynamic sea ice model in the CFSR demonstrated a recommended value of snow thermal conductivity (0.16 W m-1 K-1), and suggested that the sea ice growth was effectively restricted by the recent increase in snow depth on thin ice during winter.

  4. In situ observation of peptide bond formation at the water-air interface.

    PubMed

    Griffith, Elizabeth C; Vaida, Veronica

    2012-09-25

    We report unambiguous spectroscopic evidence of peptide bond formation at the air-water interface, yielding a possible mechanism providing insight into the formation of modern ribosomal peptide bonds, and a means for the emergence of peptides on early Earth. Protein synthesis in aqueous environments, facilitated by sequential amino acid condensation forming peptides, is a ubiquitous process in modern biology, and a fundamental reaction necessary in prebiotic chemistry. Such reactions, however, are condensation reactions, requiring the elimination of a water molecule for every peptide bond formed, and are thus unfavorable in aqueous environments both from a thermodynamic and kinetic point of view. We use the hydrophobic environment of the air-water interface as a favorable venue for peptide bond synthesis, and demonstrate the occurrence of this chemistry with in situ techniques using Langmuir-trough methods and infrared reflection absorption spectroscopy. Leucine ethyl ester (a small amino acid ester) first partitions to the water surface, then coordinates with Cu(2+) ions at the interface, and subsequently undergoes a condensation reaction selectively forming peptide bonds at the air-water interface.

  5. In situ X-ray observation and simulation of ratcheting-fatigue interactions in solder joints

    NASA Astrophysics Data System (ADS)

    Shi, Liting; Mei, Yunhui; Chen, Gang; Chen, Xu

    2017-01-01

    Reflow voids created by solder oxidation reduce the reliability of lap joints. In situ visualization of reflow voids in Sn-3Ag-0.5Cu (SAC305) lap-shear solder joints under cyclic stressing was realized by X-ray computed tomography (CT), while the ratcheting deformation of the solder joints was monitored by a non-contact displacement detecting system (NDDS). The results revealed that the shape evolution of reflow voids in solder joints, as characterized by the sphericity of the voids, can be divided into three stages: i.e., the initial stage with a sharp drop, a stable stage, and a rapidly declining stage. A new evolution law for describing the progress of sphericity was proposed, and was further introduced into a viscoplastic constitutive model based on the OW-AF nonlinear kinematic hardening rule. The damage-coupled OW-AF model yielded an accurate estimation of the whole-life ratcheting behavior of Sn-3Ag-0.5Cu (SAC305) lap-shear solder joints. [Figure not available: see fulltext.

  6. Giant radiolytic dissolution rates of aqueous ceria observed in-situ by liquid-cell TEM.

    PubMed

    Asghar, Muhammad Sajid Ali; Inkson, Beverley J; Moebus, Guenter

    2017-03-09

    Dynamics of cerium oxide nanoparticle aqueous corrosion are revealed in-situ. We use innovative liquid-cell transmission electron microscopy (TEM) combined with deliberate high-intensity electron-beam irradiation of nanoparticle suspensions. This enables life video-recording of materials reactions in liquid, with nm-resolution. We introduce image-quantification to measure detailed rates of dissolution as a function of time and particle size to be compared with literature data. Giant dissolution rates, exceeding any previous reports for chemical dissolution rates at room temperature by many orders of magnitude, are discovered. Reasons for accelerated dissolution are outlined, including the importance of radiolysis of water preceding ceria-attack. Electron-water interaction generates radicals, ions and hydrated electrons, which assist in hydration and reductive dissolution of oxide minerals. The presented methodology has the potential to become a novel accelerated testing procedure to compare multiple nanoscale materials for relative aqueous durability. The ceria-water system is of crucial importance for the fields of catalysis, abrasive polishing, environmental remediation, and as simulant for actinide-oxide behaviour in contact with liquid for nuclear engineering.

  7. Fast Printing and In-Situ Morphology Observation of Organic Photovoltaics using Slot-Die Coating

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Ferdous, Sunzida; Wang, Cheng; Hexamer, Alexander; Russell, Thomas; Cheng Wang Collaboration; Thomas Russell Team

    2014-03-01

    The solvent-processibility of polymer semiconductors is a key advantage for the fabrication of large area, organic bulk-heterojunction (BHJ) photovoltaic devices. Most reported power conversion efficiencies (PCE) are based on small active areas, fabricated by spin-coating technique. In general, this does not reflect device fabrication in an industrial setting. To realize commercial viability, devices need to be fabricated in a roll-to-roll fashion. The evolution of the morphology associated with different processing parameters, like solvent choice, concentration and temperature, needs to be understood and controlled. We developed a mini slot-die coater, to fabricate BHJ devices using various low band gap polymers mixed with phenyl-C71-butyric acid methyl ester (PCBM). Solvent choice, processing additives, coating rate and coating temperatures were used to control the final morphology. Efficiencies comparable to lab-setting spin-coated devices are obtained. The evolution of the morphology was monitored by in situ scattering measurements, detecting the onset of the polymer chain packing in solution that led to the formation of a fibrillar network in the film.

  8. In situ simulation training for paediatric cardiorespiratory arrest: initial observations and identification of latent errors.

    PubMed

    Garden, A L; Mills, S A; Wilson, R; Watts, P; Griffin, J M; Gannon, S; Kapoor, I

    2010-11-01

    In response to a successful, although difficult resuscitation in one of our paediatric wards, we developed and implemented an educational program to improve the resuscitation skills, teamwork and safety climate in our multidisciplinary acute-care paediatric service. The program is ongoing and consists of didactic presentations, high-fidelity in situ simulation and facilitated debriefing to encourage reflective learning. The underlying goal, to provide this training to all staff over a two-year period, should be achieved by late 2011. In this preliminary report we describe teamwork difficulties that are commonly found during such training. These included inconsistent leadership behaviours, inadequate delegation of areas of responsibility, failure to communicate problems during the execution of technical tasks (such as difficulty opening the resuscitation trolley) and failure to challenge inadequate or inappropriate therapy (such as poor chest expansion during bag-mask ventilation). In addition, we unexpectedly discovered seven latent errors in our clinical environment during the first nine months of course delivery. The most disturbing of these was that participants repeatedly struggled to identify and overcome the locking-mechanism and tamper-proof device on a newly introduced resuscitation trolley.

  9. Lithium electrodeposition dynamics in aprotic electrolyte observed in situ via transmission electron microscopy

    DOE PAGES

    Leenheer, Andrew Jay; Jungjohann, Katherine Leigh; Zavadil, Kevin Robert; ...

    2015-03-18

    Electrodeposited metallic lithium is an ideal negative battery electrode, but nonuniform microstructure evolution during cycling leads to degradation and safety issues. A better understanding of the Li plating and stripping processes is needed to enable practical Li-metal batteries. Here we use a custom microfabricated, sealed liquid cell for in situ scanning transmission electron microscopy (STEM) to image the first few cycles of lithium electrodeposition/dissolution in liquid aprotic electrolyte at submicron resolution. Cycling at current densities from 1 to 25 mA/cm2 leads to variations in grain structure, with higher current densities giving a more needle-like, higher surface area deposit. The effectmore » of the electron beam was explored, and it was found that, even with minimal beam exposure, beam-induced surface film formation could alter the Li microstructure. The electrochemical dissolution was seen to initiate from isolated points on grains rather than uniformly across the Li surface, due to the stabilizing solid electrolyte interphase surface film. As a result, we discuss the implications for operando STEM liquid-cell imaging and Li-battery applications.« less

  10. Developing of an environmental cell TEM holder for dynamic in situ observation

    NASA Astrophysics Data System (ADS)

    Bataineh, Khaled M.

    2016-02-01

    This paper deals with the subject of "in situ" development of environmental-transmission electron microscope (E-TEM) holder assemblies. In E-TEM, the sample is continuously subjected to gases as opposed to conventional TEM where the sample is under high vacuum. E-TEM offers the possibility of achieving a new level of material analysis. E-TEM allows obtaining information about chemical information during the reaction at atomic level. Rarefied gas dynamics analysis is used to assess the proposed design. The analysis is focused on determining the molecular distribution inside the vacuum chamber and calculating the impingement rate on the target surface of the specimen. Simulations are performed to predict the molecular interaction with the specimen at given pressures to determine the proper position of a specimen within a vacuum chamber to optimize and predict reaction characteristics. Results of direct simulation Monte Carlo show that the two sides of the sample operate at different temperatures due to the gas flow and experience different molecular distributions.

  11. In situ SEM observation of microscale strain fields around a crack tip in polycrystalline molybdenum

    NASA Astrophysics Data System (ADS)

    Li, J. J.; Li, W. C.; Jin, Y. J.; Wang, L. F.; Zhao, C. W.; Xing, Y. M.; Lang, F. C.; Yan, L.; Yang, S. T.

    2016-06-01

    In situ scanning electron microscopy was employed to investigate the crack initiation and propagation in polycrystalline molybdenum under uniaxial tensile load at room temperature. The microscale grid pattern was fabricated using the sputtering deposition technology on the specimen surface covered with a fine square mesh copper grid. The microscale strain fields around the crack tip were measured by geometric phase analysis technique and compared with the theoretical solutions based on the linear elastic fracture mechanics theory. The results showed that as the displacement increases, the crack propagated mainly perpendicular to the tensile direction during the fracture process of molybdenum. The normal strain ɛ xx and shear strain ɛ xy are relatively small, and the normal strain ɛ yy holds a dominant position in the deformation fields and plays a key role in the whole fracture process of molybdenum. With the increase in displacement, the ɛ yy increases rapidly and the two lobes grow significantly but maintain the same shape and orientation. The experimental ɛ yy is in agreement with the theoretical solution. Along the x-axis in front of the crack tip, there is minor discrepancy between the experimental ɛ yy and theoretical ɛ yy within 25 μm from the crack tip, but the agreement between them is very good far from the crack tip (>25 μm).

  12. In Situ Observation of Gypsum-Anhydrite Transition at High Pressure and High Temperature

    NASA Astrophysics Data System (ADS)

    Liu, Chuan-Jiang; Zheng, Hai-Fei

    2012-04-01

    An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC). The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa. With increasing temperature, the anhydrite (CaSO4) phase precipitates at 250-320°C in the pressure range of 1.0-1.5GPa, indicating that under a saturated water condition, both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite. A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) = 0.0068T-0.7126 (250°C<=T<=320°C). Anhydrite remained stable during rapid cooling of the sample chamber, showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature.

  13. Observation of Nanoscale Morphological and Structural Degradation in Perovskite Solar Cells by In-Situ TEM

    DOE PAGES

    Yang, Bin; Dyck, Ondrej K.; Univ. of Tennessee, Knoxville, TN; ...

    2016-11-04

    The chemical stability of organometallic halide perovskites is a major barrier facing their application in the fast rising field of next generation photovoltaics. These materials were shown to undergo degradation due to the influence of heat or moisture, significantly limiting the lifetime of associated devices. To overcome this stability issue, a fundamental understanding of degradation mechanisms is of foremost importance. Here, high resolution in situ transmission electron microscopy and electron energy loss spectroscopy elemental mapping were applied to probe morphological and structural changes in perovskite films during controlled environmental exposure treatments. Both moisture and oxygen in ambient air are revealedmore » to facilitate degradation in CH3NH3PbI3 perovskites through decomposition and oxidation pathways, respectively. In addition, even in moisture- and oxygen-free environment evident degradation could be induced by heating at the solar cell s real-field operating temperature and the degradation was found to originate from defect sites. These findings provide fundamental insight to prevent degradation of perovskite materials and associated devices for realistic applications.« less

  14. Observation of Nanoscale Morphological and Structural Degradation in Perovskite Solar Cells by In-Situ TEM

    SciTech Connect

    Yang, Bin; Dyck, Ondrej K.; Ming, Wenmei; Du, Mao-Hua; Das, Sanjib; Rouleau, Christopher M.; Duscher, Gerd; Geohegan, David B.; Xiao, Kai

    2016-11-04

    The chemical stability of organometallic halide perovskites is a major barrier facing their application in the fast rising field of next generation photovoltaics. These materials were shown to undergo degradation due to the influence of heat or moisture, significantly limiting the lifetime of associated devices. To overcome this stability issue, a fundamental understanding of degradation mechanisms is of foremost importance. Here, high resolution in situ transmission electron microscopy and electron energy loss spectroscopy elemental mapping were applied to probe morphological and structural changes in perovskite films during controlled environmental exposure treatments. Both moisture and oxygen in ambient air are revealed to facilitate degradation in CH3NH3PbI3 perovskites through decomposition and oxidation pathways, respectively. In addition, even in moisture- and oxygen-free environment evident degradation could be induced by heating at the solar cell s real-field operating temperature and the degradation was found to originate from defect sites. These findings provide fundamental insight to prevent degradation of perovskite materials and associated devices for realistic applications.

  15. Copper silicide/silicon nanowire heterostructures: in situ TEM observation of growth behaviors and electron transport properties

    NASA Astrophysics Data System (ADS)

    Chiu, Chung-Hua; Huang, Chun-Wei; Chen, Jui-Yuan; Huang, Yu-Ting; Hu, Jung-Chih; Chen, Lien-Tai; Hsin, Cheng-Lun; Wu, Wen-Wei

    2013-05-01

    Copper silicide has been studied in the applications of electronic devices and catalysts. In this study, Cu3Si/Si nanowire heterostructures were fabricated through solid state reaction in an in situ transmission electron microscope (TEM). The dynamic diffusion of the copper atoms in the growth process and the formation mechanism are characterized. We found that two dimensional stacking faults (SF) may retard the growth of Cu3Si. Due to the evidence of the block of edge-nucleation (heterogeneous) by the surface oxide, center-nucleation (homogeneous) is suggested to dominate the silicidation. Furthermore, the electrical transport properties of various silicon channel length with Cu3Si/Si heterostructure interfaces and metallic Cu3Si NWs have been investigated. The observations not only provided an alternative pathway to explore the formation mechanisms and interface properties of Cu3Si/Si, but also suggested the potential application of Cu3Si at nanoscale for future processing in nanotechnology.Copper silicide has been studied in the applications of electronic devices and catalysts. In this study, Cu3Si/Si nanowire heterostructures were fabricated through solid state reaction in an in situ transmission electron microscope (TEM). The dynamic diffusion of the copper atoms in the growth process and the formation mechanism are characterized. We found that two dimensional stacking faults (SF) may retard the growth of Cu3Si. Due to the evidence of the block of edge-nucleation (heterogeneous) by the surface oxide, center-nucleation (homogeneous) is suggested to dominate the silicidation. Furthermore, the electrical transport properties of various silicon channel length with Cu3Si/Si heterostructure interfaces and metallic Cu3Si NWs have been investigated. The observations not only provided an alternative pathway to explore the formation mechanisms and interface properties of Cu3Si/Si, but also suggested the potential application of Cu3Si at nanoscale for future processing

  16. Tundra snow cover properties from in-situ observation and multi-scale passive microwave remote sensing

    NASA Astrophysics Data System (ADS)

    Rees, Andrew

    does not change that much. The variability (CV) in among terrain categories was quite similar. The overall weighted mean CV for the study area was 0.40, which is a useful regional generalization. The terrain and landscape based classification scheme was used to generalize and extrapolate tundra SWE. Deriving a weighted mean SWE based on the spatial proportion of landscape and terrain features was shown as a method for generalizing the regional distribution of tundra SWE. The SWE data from each year were compared to AMSR-E satellite Tb. Within each season and among each of the seasons, there was little difference in 19 GHz Tb. However, there was always a large decrease in 37 GHz Tb from early November through April. The change in DeltaTb37-19 throughout each season showed that the Tb at 37 GHz is sensitive to parameters which evolve over a winter season. A principal component analysis (PCA) showed that there are differences in DeltaTb37-19 among different EASE grids and that land cover may have an influence on regional Tb. However, the PCA showed little relationship between end of season DeltaTb37-19 and lake fraction. A good relationship was found between DeltaTb 37-19 and in-situ SWE. A quadratic function was fitted to explain 89 percent of the variance in SWE from the DeltaTb37-19. The quadratic relationship provides a good fit between the data; however, the nature of the relationship is opposite to the expected linear relationship between DeltaTb37-19 and SWE. Airborne Tb data were used to examine how different snow, land cover and terrain properties influence microwave emission. In flat tundra, there was a significant relationship between SWE and high resolution DeltaTb 37-19. On lakes and slopes, no strong relationships were found between SWE and high resolution DeltaTb37-19. Due to the complexity of snow and terrain in high resolution footprints, it was a challenge to isolate a relationship between SWE and Tb. However, as the airborne footprint size increased the

  17. Initial results of detected methane emissions from landfills in the Los Angeles Basin during the COMEX campaign by the Methane Airborne MAPper (MAMAP) instrument and a greenhouse gas in-situ analyser

    NASA Astrophysics Data System (ADS)

    Krautwurst, Sven; Gerilowski, Konstantin; Kolyer, Richard; Jonsson, Haflidi; Krings, Thomas; Horstjann, Markus; Leifer, Ira; Vigil, Sam; Buchwitz, Michael; Schüttemeyer, Dirk; Fladeland, Matthew M.; Burrows, John P.; Bovensmann, Heinrich

    2015-04-01

    Methane (CH4) is the second most important anthropogenic greenhouse gas beside carbon dioxide (CO2). Significant contributors to the global methane budget are fugitive emissions from landfills. Due to the growing world population, it is expected that the amount of waste and, therefore, waste disposal sites will increase in number and size in parts of the world, often adjacent growing megacities. Besides bottom-up modelling, a variety of ground based methods (e.g., flux chambers, trace gases, radial plume mapping, etc.) have been used to estimate (top-down) these fugitive emissions. Because landfills usually are large, sometimes with significant topographic relief, vary temporally, and leak/emit heterogeneously across their surface area, assessing total emission strength by ground-based techniques is often difficult. In this work, we show how airborne based remote sensing measurements of the column-averaged dry air mole fraction of CH4 can be utilized to estimate fugitive emissions from landfills in an urban environment by a mass balance approach. Subsequently, these emission rates are compared to airborne in-situ horizontal cross section measurements of CH4 taken within the planetary boundary layer (PBL) upwind and downwind of the landfill at different altitudes immediately after the remote sensing measurements were finished. Additional necessary parameters (e.g., wind direction, wind speed, aerosols, dew point temperature, etc.) for the data inversion are provided by a standard instrumentation suite for atmospheric measurements aboard the aircraft, and nearby ground-based weather stations. These measurements were part of the CO2 and Methane EXperiment (COMEX), which was executed during the summer 2014 in California and was co-funded by the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). The remote sensing measurements were taken by the Methane Airborne MAPper (MAMAP) developed and operated by the University of Bremen and

  18. Turbulence and mountain wave conditions observed with an airborne 2-micron lidar

    NASA Technical Reports Server (NTRS)

    Teets, Edward H., Jr.; Ashburn, Chris; Ehernberger, Jack; Bogue, Rodney

    2006-01-01

    Joint efforts by the National Aeronautics and Space Administration (NASA), the Department of Defense, and industry partners are enhancing the capability of airborne wind and turbulence detection. The Airborne Coherent Lidar for Advanced In-Flight Measurements (ACLAIM) was flown on three series of flights to assess its capability over a range of altitudes, air mass conditions, and gust phenomena. This paper describes the observation of mountain waves and turbulence induced by mountain waves over the Tehachapi and Sierra Nevada mountain ranges (California, USA) by lidar onboard the NASA Airborne Science DC-8 airplane. The examples in this paper compare lidar-predicted mountain waves and wave-induced turbulence to subsequent aircraft-measured true airspeed. Airplane acceleration data is presented describing the effects of the wave-induced turbulence on the DC-8 airplane. Highlights of the lidar-predicted airspeed from the two flights show increases of 12 meters per second (m/s) at the mountain wave interface and peak-to-peak airspeed changes of 10 m/s and 15 m/s in a span of 12 seconds in moderate turbulence.

  19. Turbulence and Mountain Wave Conditions Observed with an Airborne 2-Micron Lidar

    NASA Technical Reports Server (NTRS)

    Teets, Edward H., Jr.; Ashburn, Chris; Ehernberger, L. J.; Bogue, Rodney K.

    2006-01-01

    Joint efforts by the National Aeronautics and Space Administration, the Department of Defense, and industry partners are enhancing the capability of airborne wind and turbulence detection. The Airborne Coherent Lidar (light detection and ranging) for Advanced In-Flight Measurements was flown on three series of flights to assess its capability over a range of altitudes, air mass conditions, and gust phenomena. This report describes the observation of mountain waves and turbulence induced by mountain waves over the Tehachapi and Sierra Nevada mountain ranges by lidar on board the NASA Airborne Science DC-8 (McDonnell Douglas Corporation, Long Beach, California) airplane during two flights. The examples in this report compare lidar-predicted mountain waves and wave-induced turbulence to subsequent airplane-measured true airspeed. Airplane acceleration data is presented describing the effects of the wave-induced turbulence on the DC-8 airplane. Highlights of the lidar-predicted airspeed from the two flights show increases of 12 m/s at the mountain wave interface and peak-to-peak airspeed changes of 10 m/s and 15 m/s in a span of 12 s in moderate turbulence.

  20. Turbulence and Mountain Wave Conditions Observed with an Airborne 2-Micron Lidar

    NASA Technical Reports Server (NTRS)

    Teets, Edward H., Jr.; Ehernberger, Jack; Bogue, Rodney; Ashburn, Chris

    2007-01-01

    Joint efforts by the National Aeronautics and Space Administration (NASA), the Department of Defense, and industry partners are enhancing the capability of airborne wind and turbulence detection. The Airborne Coherent Lidar for Advanced In-Flight Measurements (ACLAIM) was flown on three series of flights to assess its capability over a range of altitudes, air mass conditions, and gust phenomena. This paper describes the observation of mountain waves and turbulence induced by mountain waves over the Tehachapi and Sierra Nevada mountain ranges in southern California by lidar onboard the NASA Airborne Science DC-8 airplane. The examples in this paper compare lidar-predicted mountain waves and wave-induced turbulence to subsequent aircraft-measured true airspeed. Airplane acceleration data is presented describing the effects of the wave-induced turbulence on the DC-8 airplane. Highlights of the lidar-predicted airspeed from the two flights show increases of 12 m/s at the mountain wave interface and peak-to-peak airspeed changes of 10 m/s and 15 m/s in a span of 12 s in moderate turbulence.

  1. In situ observations of suspended particulate matter plumes at an offshore wind farm, southern North Sea

    NASA Astrophysics Data System (ADS)

    Baeye, Matthias; Fettweis, Michael

    2015-08-01

    Suspended particulate matter (SPM) plumes associated with the monopile foundations of the Belgian offshore wind farm (OWF) Belwind I were acoustically profiled by means of a Doppler current profiler (ADCP). Together with the analysis of a bottom lander dataset of optical and acoustic backscatter sensors (OBSs and ADPs respectively), the spatiotemporal SPM plume dynamics were inferred. The fieldwork comprised (1) near-bed measurements of hydrodynamics and SPM concentrations in the direct vicinity of the wind turbines, by means of a bottom lander over a spring-neap cycle in May 2010; this dataset represents a typically tide-driven situation because there was no significant meteorological forcing during the measurement period; (2) additional vessel-based measurements conducted in May 2013 to capture the SPM plumes inside and outside the OWF over part of a tidal cycle. Both in situ datasets revealed that the SPM plumes were generated at the turbine piles, consistent with aerial and space-borne imagery. The SPM plumes are well aligned with the tidal current direction in the wake of the monopiles, concentrations being estimated to reach up to 5 times that of the background concentration of about 3 mg/l. It is suggested that the epifaunal communities colonizing the monopile surface and the protective rock collar at the base play a key role as source of the suspended matter recorded in the plumes. The organisms filter and trap fine SPM from the water column, resulting in predominant accumulation of SPM, including detritus and (pseudo-) faeces, at the base of the piles. When tidal currents exceed a certain velocity, fine particles in the near-bed fluff layer are re-suspended and transported downstream in the wake of the piles.

  2. In situ observation of radiation induced amorphization of crystals with apatite structure

    SciTech Connect

    Wang, L.M.; Ewing, R.C.; Cameron, M.; Weber, W.J.; Crowley, K.D.

    1993-06-01

    Temperature dependence of amorphization doses for 1.5 MeV Kr ion-irradiated Ca{sub 10}(PO{sub 4}){sub 6}F{sub 2} and Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} were studied with in situ transmission electron microscopy. At low temperatures, Ca{sub 10}(PO{sub 4}){sub 6}F{sub 2} became amorphized at lower dose than Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2}. However, the critical amorphization dose increased much more rapidly for the former above 350 K than the latter. At 475 K, Ca{sub 10}(PO{sub 4}){sub 6}F{sub 2} required nearly five times of higher dose to become amorphous than Ca{sub 10}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2}. Based on the dose-temperature curves, activation energies for the crystal structure recovery process were determined to be 0.07 eV for Ca{sub 10}(PO{sub 4}){sub 6}F{sub 2} and 0.13 eV for Ca{sub 2}La{sub 8}(SiO{sub 4}){sub 6}O{sub 2} respectively. The lower critical amorphization dose and lower activation energy for recovery of Ca{sub 10}(PO{sub 4}){sub 6}F{sub 2} are attributed to the weaker P-O bond and the higher fluorine mobility in the structure.

  3. In-situ observation of sputtered particles for carbon implanted tungsten during energetic isotope ion implantation

    SciTech Connect

    Oya, Y.; Sato, M.; Uchimura, H.; Okuno, K.; Ashikawa, N.; Sagara, A.; Yoshida, N.; Hatano, Y.

    2015-03-15

    Tungsten is a candidate for plasma facing materials in future fusion reactors. During DT plasma operations, carbon as an impurity will bombard tungsten, leading to the formation of tungsten-carbon (WC) layer and affecting tritium recycling behavior. The effect of carbon implantation for the dynamic recycling of deuterium, which demonstrates tritium recycling, including retention and sputtering, has been investigated using in-situ sputtered particle measurements. The C{sup +} implanted W, WC and HOPG were prepared and dynamic sputtered particles were measured during H{sub 2}{sup +} irradiation. It has been found that the major hydrocarbon species for C{sup +} implanted tungsten is CH{sub 3}, while for WC and HOPG (Highly Oriented Pyrolytic Graphite) it is CH{sub 4}. The chemical state of hydrocarbon is controlled by the H concentration in a W-C mixed layer. The amount of C-H bond and the retention of H trapped by carbon atom should control the chemical form of hydrocarbon sputtered by H{sub 2}{sup +} irradiation and the desorption of CH{sub 3} and CH{sub 2} are due to chemical sputtering, although that for CH is physical sputtering. The activation energy for CH{sub 3} desorption has been estimated to be 0.4 eV, corresponding to the trapping process of hydrogen by carbon through the diffusion in W. It is concluded that the chemical states of hydrocarbon sputtered by H{sub 2}{sup +} irradiation for W is determined by the amount of C-H bond on the W surface. (authors)

  4. Airborne Active and Passive L-Band Observations in Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12)

    NASA Astrophysics Data System (ADS)

    Colliander, A.; Yueh, S. H.; Chazanoff, S.; Jackson, T. J.; McNairn, H.; Bullock, P.; Wiseman, G.; Berg, A. A.; Magagi, R.; Njoku, E. G.

    2012-12-01

    extensive ground truth collection. In situ soil moisture and vegetation biomass and structure of the mixed cropland, pasture and forest landscape of the experiment domain was gathered synchronously with the airborne acquisitions. The conditions included wide range in both soil moisture and vegetation density. This paper presents an overview of the SMAPVEX12 campaign and an evaluation of the quality of the PALS measurements. The calibration methodology based on the internal calibration, lake over-flights and specific calibration maneuvers were utilized before and after each day's science flights to guarantee accuracy and consistency of the measurements over the campaign duration. As a consequence the correspondence of the airborne acquisitions with the spatial and temporal evolution of the geophysical variables over the experiment domain meets the requirement set by the objectives of the campaign. Acknowledgement: This work was carried out in Jet Propulsion Laboratory, California Institute of Technology under contract with National Aeronautics and Space Administration. USDA is an equal opportunity provider and employer.

  5. Constraints on the Dust Size Distribution of 46P/Wirtanen from In-Situ and Ground-Based Observations

    NASA Astrophysics Data System (ADS)

    Fulle, M.

    1999-01-01

    The ESA Rosetta mission is planned to orbit around the nucleus of comet 46P/Wirtanen for years during the comet approach to its perihelion. All the probe operations will heavily depend on the dust environment of the comet, which will determine the possibility of close approaches to the nucleus, the pollution to the experiments, the good sampling of collecting dust experiments, the orbit perturbations due to the dust flux on the solar panels, and so on. A sufficiently realistic model of the dust environment requires detailed information on the nucleus surface and topography, which determines the 3D gas flux dragging the dust towards the spacecraft. Therefore, complex models of the nucleus surface and of the gas expansion are required to properly predict the environment characteristics inside which the probe will operate. These models depend on many parameters, whose most probable ranges can be determined by past in-situ measurements and available and/or future ground-based observations. We review present information about crucial parameters describing cometary dust environments, and in particular the available constraints on poorly known dust parameters, such as the dust size distribution, bulk density and loss rates provided by in-situ and ground-based observations. In particular, the most probable power index of the dust size distribution ranges bewteen -4 and -3

  6. Constraints on the dust size distribution of 46P/wirtanen from in-situ and ground-based observations

    NASA Astrophysics Data System (ADS)

    Fulle, M.

    1999-01-01

    The ESA Rosetta mission is planned to orbit around the nucleus of comet 46P/Wirtanen for years during the comet approach to its perihelion. All the probe operations will heavily depend on the dust environment of the comet, which will determine the possibility of close approaches to the nucleus, the pollution to the experiments, the good sampling of collecting dust experiments, the orbit perturbations due to the dust flux on the solar panels, and so on. A sufficiently realistic model of the dust environment requires detailed information on the nucleus surface and topography, which determines the 3D gas flux dragging the dust towards the spacecraft. Therefore, complex models of the nucleus surface and of the gas expansion are required to properly predict the environment characteristics inside which the probe will operate. These models depend on many parameters, whose most probable ranges can be determined by past in-situ measurements and available and/or future ground-based observations. We review present information about crucial parameters describing cometary dust environments, and in particular the available constraints on poorly known dust parameters, such as the dust size distribution, bulk density and loss rates provided by in-situ and ground-based observations. In particular, the most probable power index of the dust size distribution ranges between -4 and -3.

  7. In-Situ Fracture Observation and Fracture Toughness Analysis of Ni-Mn-Ga-Fe Ferromagnetic Shape Memory Alloys

    NASA Astrophysics Data System (ADS)

    Euh, Kwangjun; Lee, Jung-Moo; Nam, Duk-Hyun; Lee, Sunghak

    2011-12-01

    The fracture property improvement of Ni-Mn-Ga-Fe ferromagnetic shape memory alloys containing ductile γ particles was explained by direct observation of microfracture processes using an in-situ loading stage installed inside a scanning electron microscope (SEM) chamber. The Ni-Mn-Ga-Fe alloys contained a considerable amount of γ particles in β grains after the homogenization treatment at 1073 K to 1373 K (800 °C to 1100 °C). With increasing homogenization temperature, γ particles were coarsened and distributed homogeneously along β grain boundaries as well as inside β grains. According to the in-situ microfracture observation, γ particles effectively acted as blocking sites of crack propagation and provided the stable crack growth, which could be confirmed by the R-curve analysis. The increase in fracture resistance with increasing crack length improved overall fracture properties of the Ni-Mn-Ga-Fe alloys. This improvement could be explained by mechanisms of blocking of crack propagation and crack blunting and bridging.

  8. Room temperature deformation mechanisms of alumina particles observed from in situ micro-compression and atomistic simulations.

    DOE PAGES

    Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay D.; ...

    2015-09-22

    Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, deform, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle deformation and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental mechanisms responsible for plastic deformation/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containingmore » numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic deformation and fracture without fragmentation. Dislocation nucleation/motion, significant plastic deformation, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. As a result, the identified deformation mechanisms provide insight into feedstock design for AD.« less

  9. Room temperature deformation mechanisms of alumina particles observed from in situ micro-compression and atomistic simulations.

    SciTech Connect

    Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay D.; Mook, William M.; Bufford, Daniel Charles; Boyce, Brad L.; Hattar, Khalid Mikhiel; Kotula, Paul G.; Hall, Aaron Christopher

    2015-09-22

    Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, deform, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle deformation and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental mechanisms responsible for plastic deformation/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containing numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic deformation and fracture without fragmentation. Dislocation nucleation/motion, significant plastic deformation, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. As a result, the identified deformation mechanisms provide insight into feedstock design for AD.

  10. Oceanotron server for marine in-situ observations : a thematic data model implementation as a basis for the extensibility

    NASA Astrophysics Data System (ADS)

    Loubrieu, T.; Donnart, J. C.; Bregent, S.; Blower, J.; Griffith, G.

    2012-04-01

    Oceanotron (https://forge.ifremer.fr/plugins/mediawiki/wiki/oceanotron/index.php/Accueil) is an open-source data server dedicated to marine in-situ observation dissemination. For its extensibility it relies of an ocean business data model. IFREMER hosts the CORIOLIS marine in-situ data centre (http://www.coriolis.eu.org) and, as French NODC (National Oceanographic Data Centre, http://www.ifremer.fr/sismer/index_UK.htm), some other in-situ observation databases. As such IFREMER participates to numerous ocean data management projects. IFREMER wished to capitalize its thematic data management expertise in a dedicated data dissemination server called Oceanotron. The development of the server coordinated by IFREMER has started in 2010. Knowing the diversity of data repository formats (RDBMS, netCDF, ODV, MEDATLAS, ...) and the temperamental nature of the standard interoperability interface profiles (OGC/WMS, OGC/WFS, OGC/SOS, OpenDAP, …), the architecture of the software relies on an ocean business data model dedicated to marine in-situ observation features. The ocean business data model relies on the CSML conceptual modelling (http://csml.badc.rl.ac.uk/) and UNIDATA Common Data Model (http://www.unidata.ucar.edu/software/netcdf-java/CDM/) works and focuses on the most common marine observation features which are : vertical profiles, point series, trajectories and point. The ocean business data model has been implemented in java and can be used as an API. The oceanotron server orchestrates different types of modules handling the ocean business data model objects : - StorageUnits : which read specific data repository formats (netCDF/OceanSites, netCDF/ARGO, ...). - TransformationUnits : which apply useful ocean business related transformation to the features (for example conversion of vertical coordinates from pressure in dB to meters under sea surface). - FrontDesks : which get external requests and send results for interoperable protocols (OpenDAP, WMS, ...). These

  11. Evolution and Consequences of Interacting CMEs of 9 - 10 November 2012 Using STEREO/SECCHI and In Situ Observations

    NASA Astrophysics Data System (ADS)

    Mishra, Wageesh; Srivastava, Nandita; Chakrabarty, D.

    2015-02-01

    Understanding the kinematic evolution of coronal mass ejections (CMEs) in the heliosphere is important to estimate their arrival time at Earth. The kinematics of CMEs can change when they interact or collide with each other as they propagate in the heliosphere. In this article, we analyze the collision and post-interaction characteristics of two Earth-directed CMEs that were launched successively on 9 and 10 November 2012. To do this, we used white-light imaging observations from STEREO/SECCHI and in situ observations taken from the Wind spacecraft. We tracked two density-enhancement features associated with the leading and trailing edge of the 9 November CME and one density enhanced feature associated with the leading edges of the 10 November CME by constructing J-maps. We found that the leading edge of the 10 November CME interacted with the trailing edge of the 9 November CME. We also estimated the kinematics of these features of the CMEs and found a significant change in their dynamics after interaction. In in situ observations, we identified distinct structures associated with interacting CMEs and also observed heating and compression as signatures of their interaction. Our analysis shows an improvement in the arrival-time prediction of CMEs when their post-collision dynamics are used instead of the pre-collision dynamics. By estimating the true masses and speeds of these colliding CMEs, we investigated the nature of the observed collision, which is found to be almost perfectly inelastic. The investigation also places in perspective the geomagnetic consequences of the two CMEs and their interaction in terms of occurrence of geomagnetic storms and triggering of magnetospheric substorms.

  12. A regression approach to the mapping of bio-physical characteristics of surface sediment using in situ and airborne hyperspectral acquisitions

    NASA Astrophysics Data System (ADS)

    Ibrahim, Elsy; Kim, Wonkook; Crawford, Melba; Monbaliu, Jaak

    2017-02-01

    Remote sensing has been successfully utilized to distinguish and quantify sediment properties in the intertidal environment. Classification approaches of imagery are popular and powerful yet can lead to site- and case-specific results. Such specificity creates challenges for temporal studies. Thus, this paper investigates the use of regression models to quantify sediment properties instead of classifying them. Two regression approaches, namely multiple regression (MR) and support vector regression (SVR), are used in this study for the retrieval of bio-physical variables of intertidal surface sediment of the IJzermonding, a Belgian nature reserve. In the regression analysis, mud content, chlorophyll a concentration, organic matter content, and soil moisture are estimated using radiometric variables of two airborne sensors, namely airborne hyperspectral sensor (AHS) and airborne prism experiment (APEX) and and using field hyperspectral acquisitions by analytical spectral device (ASD). The performance of the two regression approaches is best for the estimation of moisture content. SVR attains the highest accuracy without feature reduction while MR achieves good results when feature reduction is carried out. Sediment property maps are successfully obtained using the models and hyperspectral imagery where SVR used with all bands achieves the best performance. The study also involves the extraction of weights identifying the contribution of each band of the images in the quantification of each sediment property when MR and principal component analysis are used.

  13. A regression approach to the mapping of bio-physical characteristics of surface sediment using in situ and airborne hyperspectral acquisitions

    NASA Astrophysics Data System (ADS)

    Ibrahim, Elsy; Kim, Wonkook; Crawford, Melba; Monbaliu, Jaak

    2017-01-01

    Remote sensing has been successfully utilized to distinguish and quantify sediment properties in the intertidal environment. Classification approaches of imagery are popular and powerful yet can lead to site- and case-specific results. Such specificity creates challenges for temporal studies. Thus, this paper investigates the use of regression models to quantify sediment properties instead of classifying them. Two regression approaches, namely multiple regression (MR) and support vector regression (SVR), are used in this study for the retrieval of bio-physical variables of intertidal surface sediment of the IJzermonding, a Belgian nature reserve. In the regression analysis, mud content, chlorophyll a concentration, organic matter content, and soil moisture are estimated using radiometric variables of two airborne sensors, namely airborne hyperspectral sensor (AHS) and airborne prism experiment (APEX) and and using field hyperspectral acquisitions by analytical spectral device (ASD). The performance of the two regression approaches is best for the estimation of moisture content. SVR attains the highest accuracy without feature reduction while MR achieves good results when feature reduction is carried out. Sediment property maps are successfully obtained using the models and hyperspectral imagery where SVR used with all bands achieves the best performance. The study also involves the extraction of weights identifying the contribution of each band of the images in the quantification of each sediment property when MR and principal component analysis are used.

  14. Sol-to-Gel Transition in Fast Evaporating Systems Observed by in Situ Time-Resolved Infrared Spectroscopy.

    PubMed

    Innocenzi, Plinio; Malfatti, Luca; Carboni, Davide; Takahashi, Masahide

    2015-06-22

    The in situ observation of a sol-to-gel transition in fast evaporating systems is a challenging task and the lack of a suitable experimental design, which includes the chemistry and the analytical method, has limited the observations. We synthesise an acidic sol, employing only tetraethylorthosilicate, SiCl4 as catalyst and deuterated water; the absence of water added to the sol allows us to follow the absorption from the external environment and the evaporation of deuterated water. The time-resolved data, obtained by attenuated total reflection infrared spectroscopy on an evaporating droplet, enables us to identify four different stages during evaporation. They are linked to specific hydrolysis and condensation rates that affect the uptake of water from external environment. The second stage is characterized by a decrease in hydroxyl content, a fast rise of condensation rate and an almost stationary absorption of water. This stage has been associated with the sol-to-gel transition.

  15. In situ Transmission Electron Microscopy observation of Ag nanocrystal evolution by surfactant free electron-driven synthesis

    PubMed Central

    Longo, Elson; Avansi, Waldir; Bettini, Jefferson; Andrés, Juan; Gracia, Lourdes

    2016-01-01

    The study of the interaction of electron irradiation with matter and the response of the material to the passage of electrons is a very challenging problem. However, the growth mechanism observed during nanostructural evolution appears to be a broad and promising scientific field in nanotechnology. We report the in situ TEM study of nanostructural evolution of electron-driven silver (Ag) nanocrystals through an additive-free synthetic procedure. Observations revealed the direct effect of the electron beam on the morphological evolution of Ag nanocrystals through different mechanisms, such as mass transport, site-selective coalescence, and an appropriate structural configuration after coalescence leading to a more stable configuration. A fundamental understanding of the growth and formation mechanisms of Ag nanocrystals, which interact with the electron beam, is essential to improve the nanocrystal shape-control mechanisms as well as the future design and study of nanomaterials. PMID:26979671

  16. Observation of localized heating phenomena during microwave heating of mixed powders using in situ x-ray diffraction technique

    SciTech Connect

    Sabelström, N. Hayashi, M.; Watanabe, T.; Nagata, K.

    2014-10-28

    In materials processing research using microwave heating, there have been several observations of various phenomena occurring known as microwave effects. One significant example of such a phenomenon is increased reaction kinetics. It is believed that there is a possibility that this might be caused by localized heating, were some reactants would attain a higher than apparent temperature. To examine whether such thermal gradients are indeed possible, mixed powders of two microwave non-absorbers, alumina and magnesia, were mixed with graphite, a known absorber, and heated in a microwave furnace. During microwave irradiation, the local temperatures of the respective sample constituents were measured using an in situ x-ray diffraction technique. In the case of the alumina and graphite sample, a temperature difference of around 100 °C could be observed.

  17. In-situ visual observation for the formation and dissociation of methane hydrates in porous media by magnetic resonance imaging.

    PubMed

    Zhao, Jiafei; Lv, Qin; Li, Yanghui; Yang, Mingjun; Liu, Weiguo; Yao, Lei; Wang, Shenglong; Zhang, Yi; Song, Yongchen

    2015-05-01

    In this work, magnetic resonance imaging (MRI) was employed to observe the in-situ formation and dissociation of methane hydrates in porous media. Methane hydrate was formed in a high-pressure cell with controlled temperature, and then the hydrate was dissociated by thermal injection. The process was photographed by the MRI, and the pressure was recorded. The images confirmed that the direct visual observation was achieved; these were then employed to provide detailed information of the nucleation, growth, and decomposition of the hydrate. Moreover, the saturation of methane hydrate during the dissociation was obtained from the MRI intensity data. Our results showed that the hydrate saturation initially decreased rapidly, and then slowed down; this finding is in line with predictions based only on pressure. The study clearly showed that MRI is a useful technique to investigate the process of methane hydrate formation and dissociation in porous media.

  18. Observing Metal-Catalyzed Chemical Reactions in Situ Using Surface-Enhanced Raman Spectroscopy on Pd–Au Nanoshells

    PubMed Central

    Heck, Kimberly N.; Janesko, Benjamin G.; Scuseria, Gustavo E.

    2016-01-01

    Insight into the nature of transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions is obtainable from a number of surface spectroscopic techniques. Carrying out these investigations under actual reaction conditions is preferred but remains challenging, especially for catalytic reactions that occur in water. Here, we report the direct spectroscopic study of the catalytic hydrodechlorination of 1,1-dichloroethene in H2O using surface-enhanced Raman spectroscopy (SERS). With Pd islands grown on Au nanoshell films, this reaction can be followed in situ using SERS, exploiting the high enhancements and large active area of Au nanoshell SERS substrates, the transparency of Raman spectroscopy to aqueous solvents, and the catalytic activity enhancement of Pd by the underlying Au metal. The formation and subsequent transformation of several adsorbate species was observed. These results provide the first direct evidence of the room-temperature catalytic hydrodechlorination of a chlorinated solvent, a potentially important pathway for groundwater cleanup, as a sequence of dechlorination and hydrogenation steps. More broadly, the results highlight the exciting prospects of studying catalytic processes in water in situ, like those involved in biomass conversion and proton-exchange membrane fuel cells. PMID:19554693

  19. Liquid-solid phase transition of Ge-Sb-Te alloy observed by in-situ transmission electron microscopy.

    PubMed

    Berlin, Katja; Trampert, Achim

    2016-11-05

    Melting and crystallization dynamics of the multi-component Ge-Sb-Te alloy have been investigated by in-situ transmission electron microscopy (TEM). Starting point of the phase transition study is an ordered hexagonal Ge1Sb2Te4 thin film on Si(111) where the crystal structure and the chemical composition are verified by scanning TEM and electron energy-loss spectroscopy, respectively. The in-situ observation of the liquid phase at 600°C including the liquid-solid and liquid-vacuum interfaces and their movements was made possible due to an encapsulation of the TEM sample. The solid-liquid interface during melting displays a broad and diffuse transition zone characterized by a vacancy induced disordered state. Although the velocities of interface movements are measured to be in the nanometer per second scale, both, for crystallization and solidification, the underlying dynamic processes are considerably different. Melting reveals linear dependence on time, whereas crystallization exhibits a non-linear time-dependency featuring a superimposed start-stop motion. Our results may provide valuable insight into the atomic mechanisms at interfaces during the liquid-solid phase transition of Ge-Sb-Te alloys.

  20. In situ observation of dynamic electrodeposition processes by soft x-ray fluorescence microspectroscopy and keyhole coherent diffractive imaging

    NASA Astrophysics Data System (ADS)

    Bozzini, Benedetto; Kourousias, George; Gianoncelli, Alessandra

    2017-03-01

    This paper describes two novel in situ microspectroscopic approaches to the dynamic study of electrodeposition processes: x-ray fluorescence (XRF) mapping with submicrometric space resolution and keyhole coherent diffractive imaging (kCDI) with nanometric lateral resolution. As a case study, we consider the pulse-plating of nanocomposites with polypyrrole matrix and Mn x Co y O z dispersoids, a prospective cathode material for zinc-air batteries. This study is centred on the detailed measurement of the elemental distributions developing in two representative subsequent growth steps, based on the combination of in situ identical-location XRF microspectroscopy—accompanied by soft-x ray absorption microscopy—and kCDI. XRF discloses space and time distributions of the two electrodeposited metals and kCDI on the one hand allows nanometric resolution and on the other hand provides complementary absorption as well as phase contrast modes. The joint information derived from these two microspectroscopies allows measurement of otherwise inaccessible observables that are a prerequisite for electrodeposition modelling and control accounting for dynamic localization processes.

  1. Observations of TTL water vapor and cirrus properties from the NASA Global Hawk during the Airborne Tropical TRopopause EXperiment

    NASA Astrophysics Data System (ADS)

    Thornberry, Troy; Rollins, Andrew; Gao, Ru-Shan; Woods, Sarah; Lawson, Paul; Bui, Thaopaul; Pfister, Leonhard; Fahey, David

    2015-04-01

    Despite its very low mixing ratios relative to the troposphere, water vapor in the lower stratosphere (LS) plays a significant role in Earth's radiative balance and climate system and is an important constituent in stratospheric chemistry. The low H2O content of air entering the LS is established to first order by dehydration processes controlled by the cold temperatures of the tropical tropopause layer (TTL), especially over the western Pacific. Cirrus clouds occur with high frequency and large spatial extent in the TTL, and those occurring near the thermal tropopause facilitate the final dehydration of stratosphere-bound air parcels. Uncertainties in aspects of the nucleation and growth of cirrus cloud particles and the sparseness of in situ water vapor and cirrus cloud observations with sufficient spatial resolution limit our ability to fully describe the final stages of the dehydration process before air enters the LS in the tropics. The NASA Airborne Tropical TRopopause EXperiment (ATTREX) measurement campaign has yielded more than 140 hours of sampling from the Global Hawk UAS in the Pacific TTL during deployments in winter 2013 and 2014, including more than 30 hours sampling TTL cirrus. Cirrus clouds were encountered throughout the TTL, up to the tropopause (17-18 km), with ice water contents (IWC) down to the detection limit of 3 μg m-3 and water vapor mixing ratios as low as 1.5 ppm. Most TTL cirrus sampled had particle number concentrations of less than 100 L-1, but some had concentrations ranging up to more than 1000 L-1. The mean value for relative humidity with respect to ice within cirrus was near 100%, but encompassed a range from < 50% to higher than 150%. The high spatial and temporal resolution in situ measurements of water vapor and cirrus cloud properties made during ATTREX provide an outstanding dataset by which to characterize the Pacific TTL environment and evaluate our current understanding of the dynamical and microphysical processes that

  2. Toward the Direct Measurement of Coronal Magnetic Fields: An Airborne Infrared Spectrometer for Eclipse Observations

    NASA Astrophysics Data System (ADS)

    Samra, J.; DeLuca, E. E.; Golub, L.; Cheimets, P.

    2014-12-01

    The solar magnetic field enables the heating of the corona and provides its underlying structure. Energy stored in coronal magnetic fields is released in flares and coronal mass ejections (CME) and provides the ultimate source of energy for space weather. Therefore, direct measurements of the coronal magnetic field have significant potential to enhance understanding of coronal dynamics and improve solar forecasting models. Of particular interest are observations of coronal field lines in the transitional region between closed and open flux systems, providing important information on the origin of the slow solar wind. While current instruments routinely observe only the photospheric and chromospheric magnetic fields, a proposed airborne spectrometer will take a step toward the direct observation of coronal fields by measuring plasma emission in the infrared at high spatial and spectral resolution. The targeted lines are four forbidden magnetic dipole transitions between 2 and 4 μm. The airborne system will consist of a telescope, grating spectrometer, and pointing/stabilization system to be flown on the NSF/NCAR High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) during the August 2017 total solar eclipse. The project incorporates several optical engineering challenges, centered around maintaining adequate spectral and spatial resolution in a compact and inexpensive package and on a moving platform. Design studies are currently underway to examine the tradeoffs between various optical geometries and control strategies for the pointing/stabilization system. The results will be presented and interpreted in terms of the consequences for the scientific questions. In addition, results from a laboratory prototype and simulations of the final system will be presented.

  3. Airborne Ethane Observations in the Barnett Shale: Quantification of Ethane Flux and Attribution of Methane Emissions.

    PubMed

    Smith, Mackenzie L; Kort, Eric A; Karion, Anna; Sweeney, Colm; Herndon, Scott C; Yacovitch, Tara I

    2015-07-07

    We present high time resolution airborne ethane (C2H6) and methane (CH4) measurements made in March and October 2013 as part of the Barnett Coordinated Campaign over the Barnett Shale formation in Texas. Ethane fluxes are quantified using a downwind flight strategy, a first demonstration of this approach for C2H6. Additionally, ethane-to-methane emissions ratios (C2H6:CH4) of point sources were observationally determined from simultaneous airborne C2H6 and CH4 measurements during a survey flight over the source region. Distinct C2H6:CH4 × 100% molar ratios of 0.0%, 1.8%, and 9.6%, indicative of microbial, low-C2H6 fossil, and high-C2H6 fossil sources, respectively, emerged in observations over the emissions source region of the Barnett Shale. Ethane-to-methane correlations were used in conjunction with C2H6 and CH4 fluxes to quantify the fraction of CH4 emissions derived from fossil and microbial sources. On the basis of two analyses, we find 71-85% of the observed methane emissions quantified in the Barnett Shale are derived from fossil sources. The average ethane flux observed from the studied region of the Barnett Shale was 6.6 ± 0.2 × 10(3) kg hr(-1) and consistent across six days in spring and fall of 2013.

  4. Fresh Insights into the Sources and Distribution of Peroxyacetyl Nitrate (PAN) from New In Situ and Satellite Observations

    NASA Astrophysics Data System (ADS)

    Fischer, E. V.; Payne, V.; Zaragoza, J.; Zhu, L.; Jiang, Z.; Worden, J.; Sive, B. C.; Zhou, Y.; Alvarado, M. J.; Abeleira, A.; Callahan, S. L.; Farmer, D. K.

    2014-12-01

    PAN (peroxyacetyl nitrate, CH3C(O)OONO2) is only one of the organic nitrogen compounds produced when hydrocarbons are oxidized in the presence of nitrogen oxide radicals (NOx = NO + NO2), but it is the most important atmospheric NOx reservoir and a critical pathway by which NOx reaches the remote troposphere to impact oxidant distributions and remote nitrogen deposition. We present the analysis of new in situ and satellite observations to highlight previously unobserved features of regional-to-global PAN distributions. Our latest in situ data were collected as part of the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ), which took place in the Colorado Front Range during July and August 2014. This data set serves as a case study of PAN formation where significant oil and gas production intersects a major urban-suburban region. Preliminary data, analyzed in conjunction with concurrent observations of other trace species, show extremely elevated PAN and other organic nitrogen compounds in plumes with strong oil and gas source signatures. These plumes have been observed at both suburban and remote (Rocky Mountain National Park) measurement sites. In addition, new PAN retrievals from the Tropospheric Emission Spectrometer (TES), flying on the NASA Aura satellite, can provide a more global picture of PAN. We present TES retrievals of PAN from the Northern Hemisphere over the ten-year lifetime of the Aura mission. The TES PAN dataset offers unprecedented observations of the inter-annual variability of PAN, the transpacific transport of reactive nitrogen species, and the role of biomass burning in the generation of extreme PAN abundances.

  5. First in situ observations of equatorial ionospheric bubbles by Indian satellite SROSS-C2 and simultaneous multisatellite scintillations

    NASA Astrophysics Data System (ADS)

    Paul, A.; Ray, S.; Dasgupta, A.; Garg, S. C.

    2002-10-01

    The first observation of equatorial ionospheric irregularities by RPA probe of the Indian low Earth orbiting satellite SROSS-C2 is presented in this paper. Amplitude scintillations of medium Earth orbiting Global Positioning System (GPS) satellites and geostationary FLEETSATCOM (244 MHz, 73°E) and INMARSAT (1.5 GHz, 65°E) signals recorded simultaneously at Calcutta (lat: 22.97° N, long: 88.50°E geographic; dip: 32°N) are used for a coordinated study of equatorial F region irregularities in the Indian zone. Cases of ionospheric irregularities identified from the SROSS-C2 records obtained during the initial one-and-a-half years since its launch in May 1994 have been analyzed. Some events of in situ ion density irregularities are compared with scintillations simultaneously observed on the transionospheric satellite links. Intense bite-outs of ion density (maximum relative irregularity amplitude ΔN/N ˜ 65%) were detected on one occasion (October 29, 1994) coupled with deep fadings (S4 ˜ 1 at VHF, ˜0.52 at L-band, and ˜0.69 at GPS L1 frequency) on ground-based satellite links. An estimate of scintillation indices from the observed in situ density deviations compares well with the ground-based measurements. The development of intense equatorial bubbles even on a day like October 29, 1994, under low solar activity conditions, may be attributed to a prompt penetration of magnetospheric electric field equatorwards during the main phase of a magnetic storm in progress [maximum negative excursion of Dst ˜ -127 nT at 1600UT (2100MLT) with a dDst/dt rate -37 nT/hr at 1300-1400UT (1800-1900MLT)]. The drift velocity and spatial extent of these irregularities have been estimated from ground-based observations.

  6. Distribution and habitat association of benthic fish on the Condor seamount (NE Atlantic, Azores) from in situ observations

    NASA Astrophysics Data System (ADS)

    Porteiro, Filipe M.; Gomes-Pereira, José N.; Pham, Christopher K.; Tempera, Fernando; Santos, Ricardo S.

    2013-12-01

    Distribution of fish assemblages and habitat associations of demersal fishes on the Condor seamount were investigated by analyzing in situ video imagery acquired by the Remotely-Operated Vehicles ROV SP300 and Luso 6000. A total of 51 fish taxa from 32 families were inventoried. Zooplanktivores (10 species) were the most abundant group followed by carnivores (23 species) and benthivores (18 species). Non-metric multidimensional scaling (MDS) analyses were performed on dive segments to visualize the spatial relationships between species and habitat type, substrate type or depth, with depth being the most significant parameter influencing fish distribution. Four major fish groups were identified from their vertical distribution alone: summit species (generally to <300 m depth); broad ranging species (ca. from 200 to 800 m); intermediate ranging slope species (ca. from 400 m to 800-850 m); and deeper species (800-850-1100 m). The fish fauna observed at the summit is more abundant (15.2 fish/100 m2) and habitat-specialized than the fish observed along the seamount slope. Down the seamount slope, the summit fish assemblage is gradually replaced as depth increases, with an overall reduction in abundance. On the summit, three species (Callanthias ruber, Anthias anthias and Lappanella fasciata) had higher affinity to coral habitats compared to non-coral habitats. A coherent specialized fish assemblage associated to coral habitats could not be identified, because most species were observed also in non-coral areas. On the seamount's slope (300-1100 m), no relationship between fish and coral habitats could be identified, although these might occur at larger scales. This study shows that in situ video imagery complements traditional fishing surveys, by providing information on unknown or rarely seen species, being fundamental for the development of more comprehensive ecosystem-based management towards a sustainable use of the marine environment.

  7. B33C-0612: Evaluation of Simulated Biospheric Carbon Dioxide Fluxes and Atmospheric Concentrations Using Global in Situ Observations

    NASA Technical Reports Server (NTRS)

    Philip, Sajeev; Johnson, Matthew S.; Potter, Christopher S.; Genovese, Vanessa

    2016-01-01

    Atmospheric mixing ratios of carbon dioxide (CO2) are largely controlled by anthropogenic emission sources and biospheric sources/sinks. Global biospheric fluxes of CO2 are controlled by complex processes facilitating the exchange of carbon between terrestrial ecosystems and the atmosphere. These processes which play a key role in these terrestrial ecosystem-atmosphere carbon exchanges are currently not fully understood, resulting in large uncertainties in the quantification of biospheric CO2 fluxes. Current models with these inherent deficiencies have difficulties simulating the global carbon cycle with high accuracy. We are developing a new modeling platform, GEOS-Chem-CASA by integrating the year-specific NASA-CASA (National Aeronautics and Space Administration - Carnegie Ames Stanford Approach) biosphere model with the GEOS-Chem (Goddard Earth Observation System-Chemistry) chemical transport model to improve the simulation of atmosphere-terrestrial ecosystem carbon exchange. We use NASA-CASA to explicitly represent the exchange of CO2 between terrestrial ecosystem and atmosphere by replacing the baseline GEOS-Chem land net CO2 flux and forest biomass burning CO2 emissions. We will present the estimation and evaluation of these "bottom-up" land CO2 fluxes, simulated atmospheric mixing ratios, and forest disturbance changes over the last decade. In addition, we will present our initial comparison of atmospheric column-mean dry air mole fraction of CO2 predicted by the model and those retrieved from NASA's OCO-2 (Orbiting Carbon Observatory-2) satellite instrument and model-predicted surface CO2 mixing ratios with global in situ observations. This evaluation is the first step necessary for our future work planned to constrain the estimates of biospheric carbon fluxes through "top-down" inverse modeling, which will improve our understanding of the processes controlling atmosphere-terrestrial ecosystem greenhouse gas exchanges, especially over regions which lack in

  8. A Global Synthesis Inversion Analysis of Recent Variability in Natural CO2 Fluxes Using Gosat and in Situ Observations

    NASA Astrophysics Data System (ADS)

    Wang, J. S.; Kawa, S. R.; Collatz, G. J.

    2014-12-01

    About one-half of the CO2 emissions from fossil fuel combustion and deforestation accumulates in the atmosphere, where it contributes to global warming. The rest is taken up by vegetation and the ocean. The precise contribution of the two, and the location and year-to-year variability of the CO2 sinks are, however, not well understood. We use a batch Bayesian inversion approach to deduce the global spatiotemporal distributions of CO2 fluxes during 2009-2010. For prior constraints, we utilize fluxes from the CASA-GFED model of the terrestrial biosphere and biomass burning driven by satellite observations and interannually varying meteorology. We also use measurement-based ocean flux estimates, and fixed fossil CO2 emissions. Here, we present results from our inversions that incorporate column CO2 measurements from the GOSAT satellite (ACOS retrieval, filtered and bias-corrected) and in situ observations (individual flask and afternoon-average continuous observations) to estimate fluxes in 108 regions over 8-day intervals. Relationships between fluxes and atmospheric concentrations are derived using the PCTM atmospheric transport model run at 2° x 2.5° (latitude/longitude) resolution driven by meteorology from the MERRA reanalysis. We evaluate the posterior CO2 concentrations using independent aircraft and other data sets. The optimized fluxes generally resemble those from other inversion systems using different techniques, for example indicating a net terrestrial biospheric CO2 sink, and a shift in the sink from tropics to northern high latitudes when going from an in-situ-only inversion to a GOSAT inversion. We show that in this inversion framework, GOSAT provides better flux estimates in most regions with its greater spatial coverage, but we also discuss impacts of possible remaining biases in the data.

  9. Release History of Solar Energetic Electrons Inferred from In-situ Observations in the Inner Heliosphere

    NASA Astrophysics Data System (ADS)

    Agueda, Neus; Lario, David

    2016-07-01

    We present a detailed study of four 300-800 keV electron events observed on 1980 May 28-29 by Helios-1, when the spacecraft was located at 0.31 AU from the Sun. We use two different techniques to extract the release time history of the electrons at the Sun: 1) an inversion method that makes use of particle transport simulation results, and 2) a data-driven method based on the assumption that the interplanetary propagation between the Sun and the spacecraft is essentially scatter free. Both methods make use of the particle angular distributions measured relative to the local direction of the magnetic field (i.e., pitch-angle distributions). The general characteristics of the release time profile obtained for the four events is remarkably similar, specially when the inferred value of the electron mean free path is large. We use these results to compute the expected intensities at 1 AU. For an observer at 1 AU magnetically connected with Helios-1, our simulations predict the observation of four separate events, which does not agree with the interpretation of the IMP-8 observations suggesting that the discrete events observed at 0.31 AU merged into a single event at 1 AU. We discuss the processes that could contribute to the observation of one single time-extended event at 1 AU and how these techniques could be used to analyze upcoming measurements by Solar Orbiter and Solar Probe Plus close to the Sun.

  10. Utilizing Free and Open Source Software to access, view and compare in situ observations, EO products and model output data

    NASA Astrophysics Data System (ADS)

    Vines, Aleksander; Hamre, Torill; Lygre, Kjetil

    2014-05-01

    The GreenSeas project (Development of global plankton data base and model system for eco-climate early warning) aims to advance the knowledge and predictive capacities of how marine ecosystems will respond to global change. A main task has been to set up a data delivery and monitoring core service following the open and free data access policy implemented in the Global Monitoring for the Environment and Security (GMES) programme. The aim is to ensure open and free access to historical plankton data, new data (EO products and in situ measurements), model data (including estimates of simulation error) and biological, environmental and climatic indicators to a range of stakeholders, such as scientists, policy makers and environmental managers. To this end, we have developed a geo-spatial database of both historical and new in situ physical, biological and chemical parameters for the Southern Ocean, Atlantic, Nordic Seas and the Arctic, and organized related satellite-derived quantities and model forecasts in a joint geo-spatial repository. For easy access to these data, we have implemented a web-based GIS (Geographical Information Systems) where observed, derived and forcasted parameters can be searched, displayed, compared and exported. Model forecasts can also be uploaded dynamically to the system, to allow modelers to quickly compare their results with available in situ and satellite observations. We have implemented the web-based GIS(Geographical Information Systems) system based on free and open source technologies: Thredds Data Server, ncWMS, GeoServer, OpenLayers, PostGIS, Liferay, Apache Tomcat, PRTree, NetCDF-Java, json-simple, Geotoolkit, Highcharts, GeoExt, MapFish, FileSaver, jQuery, jstree and qUnit. We also wanted to used open standards to communicate between the different services and we use WMS, WFS, netCDF, GML, OPeNDAP, JSON, and SLD. The main advantage we got from using FOSS was that we did not have to invent the wheel all over again, but could use

  11. Review: advances in in situ and satellite phenological observations in Japan

    NASA Astrophysics Data System (ADS)

    Nagai, Shin; Nasahara, Kenlo Nishida; Inoue, Tomoharu; Saitoh, Taku M.; Suzuki, Rikie

    2016-04-01

    To accurately evaluate the responses of spatial and temporal variation of ecosystem functioning (evapotranspiration and photosynthesis) and services (regulating and cultural services) to the rapid changes caused by global warming, we depend on long-term, continuous, near-surface, and satellite remote sensing of phenology over wide areas. Here, we review such phenological studies in Japan and discuss our current knowledge, problems, and future developments. In contrast with North America and Europe, Japan has been able to evaluate plant phenology along vertical and horizontal gradients within a narrow area because of the country's high topographic relief. Phenological observation networks that support scientific studies and outreach activities have used near-surface tools such as digital cameras and spectral radiometers. Differences in phenology among ecosystems and tree species have been detected by analyzing the seasonal variation of red, green, and blue digital numbers (RGB values) extracted from phenological images, as well as spectral reflectance and vegetation indices. The relationships between seasonal variations in RGB-derived indices or spectral characteristics and the ecological and CO2 flux measurement data have been well validated. In contrast, insufficient satellite remote-sensing observations have been conducted because of the coarse spatial resolution of previous datasets, which could not detect the heterogeneous plant phenology that results from Japan's complex topography and vegetation. To improve Japanese phenological observations, multidisciplinary analysis and evaluation will be needed to link traditional phenological observations with "index trees," near-surface and satellite remote-sensing observations, "citizen science" (observations by citizens), and results published on the Internet.

  12. Review: advances in in situ and satellite phenological observations in Japan.

    PubMed

    Nagai, Shin; Nasahara, Kenlo Nishida; Inoue, Tomoharu; Saitoh, Taku M; Suzuki, Rikie

    2016-04-01

    To accurately evaluate the responses of spatial and temporal variation of ecosystem functioning (evapotranspiration and photosynthesis) and services (regulating and cultural services) to the rapid changes caused by global warming, we depend on long-term, continuous, near-surface, and satellite remote sensing of phenology over wide areas. Here, we review such phenological studies in Japan and discuss our current knowledge, problems, and future developments. In contrast with North America and Europe, Japan has been able to evaluate plant phenology along vertical and horizontal gradients within a narrow area because of the country's high topographic relief. Phenological observation networks that support scientific studies and outreach activities have used near-surface tools such as digital cameras and spectral radiometers. Differences in phenology among ecosystems and tree species have been detected by analyzing the seasonal variation of red, green, and blue digital numbers (RGB values) extracted from phenological images, as well as spectral reflectance and vegetation indices. The relationships between seasonal variations in RGB-derived indices or spectral characteristics and the ecological and CO2 flux measurement data have been well validated. In contrast, insufficient satellite remote-sensing observations have been conducted because of the coarse spatial resolution of previous datasets, which could not detect the heterogeneous plant phenology that results from Japan's complex topography and vegetation. To improve Japanese phenological observations, multidisciplinary analysis and evaluation will be needed to link traditional phenological observations with "index trees," near-surface and satellite remote-sensing observations, "citizen science" (observations by citizens), and results published on the Internet.

  13. In-situ observations of high-latitude thermosphere-mesosphere turbulence

    NASA Astrophysics Data System (ADS)

    Wanliss, James; Larsen, Miguel

    2011-01-01

    Sounding rocket measurements have provided some of the most detailed observations of the small-scale response of the neutral lower thermosphere to magnetospheric energy input in the auroral zone. In January and February 2007, a series of such launches were carried out at Poker Flat, Alaska. We were able to detect the development of atmospheric turbulence near 100 km through analysis of the trimethyl aluminum (TMA) re-entry bag. The atmospheric turbulence develops soon after the cloud forms, and proceeds from Navier-Stokes through Kraichnan turbulence in the most diffuse observations.

  14. Copper silicide/silicon nanowire heterostructures: in situ TEM observation of growth behaviors and electron transport properties.

    PubMed

    Chiu, Chung-Hua; Huang, Chun-Wei; Chen, Jui-Yuan; Huang, Yu-Ting; Hu, Jung-Chih; Chen, Lien-Tai; Hsin, Cheng-Lun; Wu, Wen-Wei

    2013-06-07

    Copper silicide has been studied in the applications of electronic devices and catalysts. In this study, Cu3Si/Si nanowire heterostructures were fabricated through solid state reaction in an in situ transmission electron microscope (TEM). The dynamic diffusion of the copper atoms in the growth process and the formation mechanism are characterized. We found that two dimensional stacking faults (SF) may retard the growth of Cu3Si. Due to the evidence of the block of edge-nucleation (heterogeneous) by the surface oxide, center-nucleation (homogeneous) is suggested to dominate the silicidation. Furthermore, the electrical transport properties of various silicon channel length with Cu3Si/Si heterostructure interfaces and metallic Cu3Si NWs have been investigated. The observations not only provided an alternative pathway to explore the formation mechanisms and interface properties of Cu3Si/Si, but also suggested the potential application of Cu3Si at nanoscale for future processing in nanotechnology.

  15. In-Situ Observation of Crystallization and Growth in High-Temperature Melts Using the Confocal Laser Microscope

    NASA Astrophysics Data System (ADS)

    Sohn, Il; Dippenaar, Rian

    2016-08-01

    This review discusses the innovative efforts initiated by Emi and co-workers for in-situ observation of phase transformations at high temperatures for materials. By using the high-temperature confocal laser-scanning microscope (CLSM), a robust database of the phase transformation behavior during heating and cooling of slags, fluxes, and steel can be developed. The rate of solidification and the progression of solid-state phase transformations can be readily investigated under a variety of atmospheric conditions and be correlated with theoretical predictions. The various research efforts following the work of Emi and co-workers have allowed a deeper fundamental understanding of the elusive solidification and phase transformation mechanisms in materials beyond the ambit of steels. This technique continues to evolve in terms of its methodology, application to other materials, and its contribution to technology.

  16. Firsthand in situ observation of active fine laser tuning by combining a temperature gradient and a CLC wedge cell structure.

    PubMed

    Jeong, Mi-Yun; Cha, Jihun

    2015-08-10

    In situ direct observation of the lasing process in a cholesteric liquid crystal (CLC) laser array using a CMOS camera was used to investigate discontinuous laser tuning in a parallel CLC cell. In accordance with the discontinuous pitch change by thermal energy transfer, at the same time the laser wavelength undergoes an immediate and discontinuous shift. And we found out the reason why the CLC phase has domain textures. And this work develops a simple active tunable laser array by forming a spatial temperature gradient along a wedge CLC cell. With this new strategy, only just about 7 nm laser tuning range at room temperature is extremely widened over the 105 nm wavelength range with about 0.2 nm tuning resolution. Furthermore, there is no aging effect because the employed CLC array has only one chiral molecular concentration. This strategy could be used in a practical CLC laser device application.

  17. In-situ observation of self-regulated switching behavior in WO{sub 3-x} based resistive switching devices

    SciTech Connect

    Hong, D. S.; Wang, W. X.; Chen, Y. S. Sun, J. R.; Shen, B. G.

    2014-09-15

    The transmittance of tungsten oxides can be adjusted by oxygen vacancy (V{sub o}) concentration due to its electrochromic property. Here, we report an in-situ observation of resistive switching phenomenon in the oxygen-deficient WO{sub 3-x} planar devices. Besides directly identifying the formation/rupture of dark-colored conductive filaments in oxide layer, the stripe-like WO{sub 3-x} device demonstrated self-regulated switching behavior during the endurance testing, resulting in highly consistent switching parameters after a stabilizing process. For very high V{sub o}s mobility was demonstrated in the WO{sub 3-x} film by the pulse experiment, we suggested that the electric-field-induced homogeneous migration of V{sub o}s was the physical origin for such unique switching characteristics.

  18. GPS and in situ Swarm observations of the equatorial plasma density irregularities in the topside ionosphere

    NASA Astrophysics Data System (ADS)

    Zakharenkova, Irina; Astafyeva, Elvira; Cherniak, Iurii

    2016-07-01

    Here we study the global distribution of the plasma density irregularities in the topside ionosphere by using the concurrent GPS and Langmuir probe measurements onboard the Swarm satellites. We analyze 18 months (from August 2014 till January 2016) of data from Swarm A and B satellites that flew at 460 and 510 km altitude, respectively. To identify the occurrence of the ionospheric irregularities, we have analyzed behavior of two indices ROTI and RODI based on the change rate of total electron content and electron density, respectively. The obtained results demonstrate a high degree of similarities in the occurrence pattern of the seasonal and longitudinal distribution of the topside ionospheric irregularities derived from both types of the satellite observations. Among the seasons with good data coverage, the maximal occurrence rates for the post-sunset equatorial irregularities reached 35-50 % for the September 2014 and March 2015 equinoxes and only 10-15 % for the June 2015 solstice. For the equinox seasons the intense plasma density irregularities were more frequently observed in the Atlantic sector, for the December solstice in the South American-Atlantic sector. The highest occurrence rates for the post-midnight irregularities were observed in African longitudinal sector during the September 2014 equinox and June 2015 solstice. The observed differences in SWA and SWB results could be explained by the longitude/LT separation between satellites, as SWB crossed the same post-sunset sector increasingly later than the SWA did.

  19. Liparid and macrourid fishes of the hadal zone: in situ observations of activity and feeding behaviour

    PubMed Central

    Jamieson, A.J.; Fujii, T.; Solan, M.; Matsumoto, A.K.; Bagley, P.M.; Priede, I.G.

    2008-01-01

    Using baited camera landers, the first images of living fishes were recorded in the hadal zone (6000–11 000 m) in the Pacific Ocean. The widespread abyssal macrourid Coryphaenoides yaquinae was observed at a new depth record of approximately 7000 m in the Japan Trench. Two endemic species of liparid were observed at similar depths: Pseudoliparis amblystomopsis in the Japan Trench and Notoliparis kermadecensis in the Kermadec Trench. From these observations, we have documented swimming and feeding behaviour of these species and derived the first estimates of hadal fish abundance. The liparids intercepted bait within 100–200 min but were observed to preferentially feed on scavenging amphipods. Notoliparis kermadecensis act as top predators in the hadal food web, exhibiting up to nine suction-feeding events per minute. Both species showed distinctive swimming gaits: P. amblystomopsis (mean length 22.5 cm) displayed a mean tail-beat frequency of 0.47 Hz and mean caudal : pectoral frequency ratio of 0.76, whereas N. kermadecensis (mean length 31.5 cm) displayed respective values of 1.04 and 2.08 Hz. Despite living at extreme depths, these endemic liparids exhibit similar activity levels compared with shallow-water liparids. PMID:19129104

  20. Liparid and macrourid fishes of the hadal zone: in situ observations of activity and feeding behaviour.

    PubMed

    Jamieson, A J; Fujii, T; Solan, M; Matsumoto, A K; Bagley, P M; Priede, I G

    2009-03-22

    Using baited camera landers, the first images of living fishes were recorded in the hadal zone (6000-11000 m) in the Pacific Ocean. The widespread abyssal macrourid Coryphaenoides yaquinae was observed at a new depth record of approximately 7000 m in the Japan Trench. Two endemic species of liparid were observed at similar depths: Pseudoliparis amblystomopsis in the Japan Trench and Notoliparis kermadecensis in the Kermadec Trench. From these observations, we have documented swimming and feeding behaviour of these species and derived the first estimates of hadal fish abundance. The liparids intercepted bait within 100-200 min but were observed to preferentially feed on scavenging amphipods. Notoliparis kermadecensis act as top predators in the hadal food web, exhibiting up to nine suction-feeding events per minute. Both species showed distinctive swimming gaits: P. amblystomopsis (mean length 22.5 cm) displayed a mean tail-beat frequency of 0.47 Hz and mean caudal:pectoral frequency ratio of 0.76, whereas N. kermadecensis (mean length 31.5 cm) displayed respective values of 1.04 and 2.08 Hz. Despite living at extreme depths, these endemic liparids exhibit similar activity levels compared with shallow-water liparids.

  1. Structural changes of polyacetylenes in American ginseng root can be observed in situ by using Raman spectroscopy.

    PubMed

    Baranska, Malgorzata; Schulz, Hartwig; Christensen, Lars P

    2006-05-17

    The presented results show the special advantage of Raman spectroscopy in the investigation of polyacetylenes in American ginseng (Panax quinquefolium L.) roots. The compounds are measured directly in the plant tissue without any preliminary sample preparation. The polyacetylene signal is strong and well-separated from other bands so the spectral impact of the surrounding biological matrix can be clearly distinguished. The Raman spectrum taken in situ from the fresh ginseng root revealed a characteristic polyacetylene key band at 2237 cm(-1) whereas in the spectrum obtained from dried root this band was shifted to about 2258 cm(-1). The latter is in good agreement with signals obtained from isolated standards, falcarinol (2258 cm(-1)) and panaxydol (2260 cm(-1)), occurring as predominant polyacetylenes in this species. The shift of the polyacetylene band observed in root extracts or at a certain stage of root drying indicates the molecular modification of polyacetylenes resulting from the loss of water. Furthermore, it was found that the process upon root hydration is reversible as the shift of polyacetylene band from 2258 to 2237 cm(-1) is observed. An explanation of this phenomenon can be an interaction of polyacetylene molecules with plant components in the presence of water molecules forming a stable entity in situ that is broken after dehydration (loss of water) of the fresh ginseng root. Application of the Raman mapping technique to ginseng roots of different size showed that the content of both main polyacetylenes decreases with increasing root size in accordance with quantitative high-performance liquid chromatography data.

  2. In situ observation of water behavior at the surface and buried interface of a low-k dielectric film.

    PubMed

    Zhang, Xiaoxian; Myers, John N; Bielefeld, Jeffery D; Lin, Qinghuang; Chen, Zhan

    2014-11-12

    Water adsorption in porous low-k dielectrics has become a significant challenge for both back-end-of-line integration and reliability. A simple method is proposed here to achieve in situ observation of water structure and water-induced structure changes at the poly(methyl silsesquioxane) (PMSQ) surface and the PMSQ/solid buried interface at the molecular level by combining sum frequency generation (SFG) vibrational spectroscopic and Fourier transform infrared (FTIR) spectroscopic studies. First, in situ SFG investigations of water uptake were performed to provide direct evidence that water diffuses predominantly along the PMSQ/solid interface rather than through the bulk. Furthermore, SFG experiments were conducted at the PMSQ/water interface to simulate water behavior at the pore inner surfaces for porous low-k materials. Water molecules were found to form strong hydrogen bonds at the PMSQ surface, while weak hydrogen bonding was observed in the bulk. However, both strongly and weakly hydrogen bonded water components were detected at the PMSQ/SiO2 buried interface. This suggests that the water structures at PMSQ/solid buried interfaces are also affected by the nature of solid substrate. Moreover, the orientation of the Si-CH3 groups at the buried interface was permanently changed by water adsorption, which might due to low flexibility of Si-CH3 groups at the buried interface. In brief, this study provides direct evidence that water molecules tend to strongly bond (chemisorbed) with low-k dielectric at pore inner surfaces and at the low-k/solid interface of porous low-k dielectrics. Therefore, water components at the surfaces, rather than the bulk, are likely more responsible for chemisorbed water related degradation of the interconnection layer. Although the method developed here was based on a model system study, we believe it should be applicable to a wide variety of low-k materials.

  3. Seismic anisotropy in ice: numerical modelling, ice core measurements and in-situ observations

    NASA Astrophysics Data System (ADS)

    Kendall, J. M.; Baird, A. F.; Walker, A.; Wookey, J. M.; Lloyd, G. E.; Stuart, G. W.; Harland, S.; Obbard, R. W.; Smith, A.; Brisbourne, A.

    2013-12-01

    The stress distribution and style of flow in ice produces elastic and rheological anisotropy, which informs ice flow modelling as to how ice masses respond to external changes such as global warming. Here observations of shear wave splitting from three-component icequake seismograms are used to characterise ice anisotropy in the Rutford ice stream, West Antarctica. Over 110 high quality measurements are made on 41 events recorded at five stations temporarily deployed near the ice stream grounding line. The magnitude of the splitting ranges from 2ms to 80ms and suggest a maximum of 6% shear wave splitting. The fast shear wave polarisation direction is roughly perpendicular to the ice flow direction. Motivated by these observations, we consider mechanisms for seismic anisotropy in ice using numerical modelling of the development of crystal preferred orientation of ice and measurement of crystal alignment in an ice core using electron back-scattered diffraction (EBSD). These results suggest transitions in the style of anisotropy both with depth and laterally within an ice stream. Seismic anisotropy is developed with increasing hydrostatic pressure producing a VTI fabric with a vertical alignment of c-axes (so-called cluster fabric). However, convergence in the ice flow and along-flow extension leads to girdles of c-axes (and an HTI fabric). Based on the Rutford shear-wave splitting observations we can rule out a cluster fabric as the sole cause of anisotropy - an HTI component is needed, which may be due extension in the direction of flow forming a girdle fabric or the alignment of cracks or ice-films in the plane perpendicular to the flow direction. Cumulatively, our observations suggest a combination of anisotropy mechanisms are at play in deforming ice sheets. We discuss seismic measurements that can be made to better discriminate between plausible mechanisms for our shear-wave splitting observations and how these different mechanisms may in turn alter ice flow and

  4. A Quantitative Approach for Collocating NEON's Sensor-Based Ecological Measurements and in-situ Field Sampling and Observations

    NASA Astrophysics Data System (ADS)

    Zulueta, R. C.; Metzger, S.; Ayres, E.; Luo, H.; Meier, C. L.; Barnett, D.; Sanclements, M.; Elmendorf, S.

    2013-12-01

    The National Ecological Observatory Network (NEON) is a continental-scale research platform currently in development to assess the causes of ecological change and biological responses to change across a projected 30-year timeframe. A suite of standardized sensor-based measurements (i.e., Terrestrial Instrument System (TIS) measurements) and in-situ field sampling and observations (i.e., Terrestrial Observation System (TOS) activities) will be conducted across 20 ecoclimatic domains in the U.S. where NEON is establishing 60 terrestrial research sites. NEON's TIS measurements and TOS activities are designed to observe the temporal and spatial dynamics of key drivers and ecological processes and responses to change within each of the 60 terrestrial research sites. The TIS measurements are non-destructive and designed to provide in-situ, continuous, and areally integrated observations of the surrounding ecosystem and environment, while TOS sampling and observation activities are designed to encompass a hierarchy of measurable biological states and processes including diversity, abundance, phenology, demography, infectious disease prevalence, ecohydrology, and biogeochemistry. To establish valid relationships between these drivers and site-specific responses, two contradicting requirements must be fulfilled: (i) both types of observations shall be representative of the same ecosystem, and (ii) they shall not significantly influence one another. Here we outline the theoretical background and algorithmic process for determining areas of mutual representativeness and exclusion around NEON's TIS measurements and develop a procedure which quantitatively optimizes this trade-off through: (i) quantifying the source area distributions of TIS measurements, (ii) determining the ratio of user-defined impact threshold to effective impact area for different TOS activities, and (iii) determining the range of feasible distances between TIS locations and TOS activities. This approach

  5. Estimation of country-scale methane emissions by airborne and ground-based in situ observations and inverse modeling

    NASA Astrophysics Data System (ADS)

    Brunner, D.; Henne, S.; Oney, B. J.; Leuenberger, M.; Hiller, R.; Bamberger, I.; Eugster, W.; Neininger, B.

    2014-12-01

    The Arctic region is warming at a rate nearly double the global average, and this trend is predicted to continue for the coming decades, as simulated in the Coupled Model Intercomparison Project 5 (CMIP5) climate projections. Despite the consistency in the projected surface warming rate relative to the globe, significant inter-model spread is found in the overall magnitude of Arctic surface temperature change, which leads to large inter-model spread in the simulation of surface radiative properties. The goal of this presentation is to determine the biases in the representation of the Arctic surface radiation budget seasonal cycle and discover the physical processes that explain the significant spread in projected Arctic warming. First, biases in the simulated Arctic surface radiation budget seasonal cycle within several CMIP5 climate models participating in the Historical forcing scenario are evaluated with respect to the CERES-SFC-EBAF and C3M data products. Next, the equations for longwave and shortwave cloud radiative forcing are decomposed using an independent column approximation (ICA) to identify which factors are driving changes to the annual cycle of cloud radiative forcing as well as what terms are contributing to the inter-model spread in the simulation of the surface energy budget. A multiple linear regression methodology is applied to the results of the ICA analysis using four atmospheric state variables as predictors: surface pressure, lower tropospheric stability, sea-ice concentration, and surface temperature. The impact of thermodynamics, atmospheric dynamics, and cloud-sea ice interactions on the annual cycle of cloud radiative effect will be determined.

  6. In situ observations of a high-pressure phase of H2O ice

    USGS Publications Warehouse

    Chou, I.-Ming; Blank, J.G.; Goncharov, A.F.; Mao, Ho-kwang; Hemley, R.J.

    1998-01-01

    A previously unknown solid phase of H2O has been identified by its peculiar growth patterns, distinct pressure-temperature melting relations, and vibrational Raman spectra. Morphologies of ice crystals and their pressure-temperature melting relations were directly observed in a hydrothermal diamond-anvil cell for H2O bulk densities between 1203 and 1257 kilograms per cubic meter at temperatures between -10??and 50??C. Under these conditions, four different ice forms were observed to melt: two stable phases, ice V and ice VI, and two metastable phases, ice IV and the new ice phase. The Raman spectra and crystal morphology are consistent with a disordered anisotropic structure with some similarities to ice VI.

  7. Cluster observations of the plasma sheet at very high latitudes: The in situ signature of a transpolar arc

    NASA Astrophysics Data System (ADS)

    Fear, R. C.; Milan, S. E.; Maggiolo, R.

    2013-12-01

    Transpolar arcs are auroral features which extend into the polar cap, which is the dim region poleward of the main auroral oval. Several case and statistical studies have shown that they are formed by the closure of lobe magnetic flux by magnetotail reconnection, and that the transpolar arc forms at the footprints of the newly-closed field lines which are embedded within the open flux of the polar cap. Therefore, when transpolar arcs occur, the magnetotail should contain closed magnetic field lines even at high latitudes (but in a localised sector), embedded within the open lobe flux. We present in situ observations of this phenomenon, taken by the Cluster spacecraft on 15th September 2005. Cluster was located at high latitudes in the southern hemisphere lobe (far from the typical location of the plasma sheet), and a transpolar arc was observed by the FUV cameras on the IMAGE satellite. An initial analysis reveals that Cluster periodically observed plasma similar to a typical plasma sheet distribution, but at much higher latitudes - indicative of closed flux embedded within the high latitude lobe. Each time that this plasma distribution was observed, the footprint of the spacecraft mapped to the transpolar arc (significantly poleward of the main auroral oval). These observations are consistent with closed flux being trapped in the magnetotail and embedded within the lobe, and provide further evidence for transpolar arcs being formed by magnetotail reconnection.

  8. Fast printing and in situ morphology observation of organic photovoltaics using slot-die coating.

    PubMed

    Liu, Feng; Ferdous, Sunzida; Schaible, Eric; Hexemer, Alexander; Church, Matthew; Ding, Xiaodong; Wang, Cheng; Russell, Thomas P

    2015-02-04

    The mini-slot-die coater offers a simple, convenient, materials-efficient route to print bulk-heterojunction (BHJ) organic photovoltaics (OPVs) that show efficiencies similar to spin-coating. Grazing-incidence X-ray diffraction (GIXD) and GI small-angle X-ray scattering (GISAXS) methods are used in real time to characterize the active-layer formation during printing. A polymer-aggregation-phase-separation-crystallization mechanism for the evolution of the morphology describes the observations.

  9. Integration of space and in-situ observations to study atmosphere, ocean and land processes

    NASA Technical Reports Server (NTRS)

    Shukla, J.; Kinter, J. L., III

    1992-01-01

    A research investigation was conducted into the possibility of using atmospheric observations made in the past from both terrestrial and space-based platforms to create a global, coherent four dimensional analysis for the purpose of studying atmospheric, oceanic, and land surface processes relevant to climate simulation, monitoring, and change. This investigation consisted of the following tasks: (1) a mature global data assimilation system was obtained from the National Meteorological Center and modified for use on a Cray X-MP computer system; (2) atmospheric observations for the period 20 Nov. 1982 through 1 Mar. 1983, including rawinsonde soundings, aircraft-based measurements, pilot balloons, and temperature soundings from polar orbiting satellites were obtained from several sources; and (3) the global data assimilation system was used to reassimilate the atmospheric observations to produce a new atmospheric analysis which was then compared with the contemporaneous analysis. The global hydrologic cycle, including fluxes between the atmosphere and both the land and ocean surfaces, was estimated. The flux of water from the ocean surface into the atmosphere, its transport in the form of latent heat to remote regions, and its return to the surface in the form of precipitation were estimated globally. In addition, several regional budgets for selected tropical oceanic and extratropical continental areas were also done.

  10. Fishes of the hadal zone including new species, in situ observations and depth records of Liparidae

    NASA Astrophysics Data System (ADS)

    Linley, Thomas D.; Gerringer, Mackenzie E.; Yancey, Paul H.; Drazen, Jeffrey C.; Weinstock, Chloe L.; Jamieson, Alan J.

    2016-08-01

    Observations and records for fish exceeding 6000 m deep are few and often spurious. Recent developments in accessing and sampling the hadal zone 6000-11,000 m) have led to an acceleration in new findings in the deep subduction trenches, particularly in the Pacific Ocean. This study describes the discovery of two new species of snailfish (Liparidae) from the Mariana Trench; the 'Mariana snailfish' (6198-8076 m) and the 'Ethereal snailfish' (7939-8145 m). These new findings represent respectively the deepest known specimen caught with corroborating depth data, and the deepest fish seen alive. Further specimens and observations of the Kermadec Trench snailfish, Notoliparis kermadecensis, are also presented, as well as the first hadal records of Synaphobranchidae and Zoarcidae (6068 and 6145 m respectively) and a depth extension for the Macrouridae (maximum depth now 7012 m). Details of these new snailfish specimens caught by baited trap and behaviour observations filmed by baited cameras are presented. An updated assessment of fishes from hadal depths is also reported.

  11. In-situ Observations of Gamma-ray Production in Thunderstorms

    NASA Astrophysics Data System (ADS)

    Eack, Kenneth; Aulich, Graydon; Winn, William; Edens, Harald

    2016-04-01

    The majority of the reported observations of energetic radiation from thunderstorms have come from either ground-based or satellite-based measurements. In order to better understand the physical conditions necessary for the production of fast electrons and gamma-rays, measurements are needed near the production regions inside or above the thunderstorm. Three different measurements are of particular interest. First, gamma-rays produced by the quasi-static electric-field may provide details about the physics of runaway electrons that would be difficult to determine from measurements of transient phenomena, such as lightning and terrestrial gamma-ray flashes (TGFs). Second, what process inside the thunderstorm is responsible for TGFs? Recent ground-bsed studies have pointed to the upward negative leader in inter-cloud lightning as a possible source. Finally, the initiation of lightning appears to be a problem in light of the relatively weak (about 10% of the classical breakdown threshold) electric fields observed inside thunderstorms. Since these field strengths are adequate for runaway electrons, they have been proposed as a possible source for the initial breakdown in lightning. In this paper, we will present observations from balloon-borne gamma-ray detectors and electric-field sensors, as well as ground based instruments like the lightning mapping array (LMA) in effort to examine these areas of interest.

  12. In Situ Observation of the Electrochemical Lithiation of a Single SnO2 Nanowire Electrode

    SciTech Connect

    Huang, J. Y.; Zhong, Li; Wang, Chong M.; Sullivan, John P.; Xu, Wu; Zhang, Li Q.; Mao, Scott; Hudak, N.; Liu, Xiao H.; Subramanian, Arun Kumar; Fan, Hongyou; Qi, Liang; Kushima, Akihiro; Li, Ju

    2010-11-18

    We report the first real-time transmission electron microscopy (TEM) observations of the structural evolution and phase transformation of lithium-ion battery anode during the battery charging process. A nanobattery consisting of a single SnO2 nanowire anode and an ionic liquid electrolyte was successfully constructed in a TEM. We observed that during the charging process, the SnO2 crystal was converted to Li2O glass with LixSn nanocrystalline precipitates as the reaction front propagated progressively along the nanowire. After the reaction front passed, the nanowire showed swelling, elongation, and large off-axis distortion (spiraling). Upon completion of the electrochemical charging, the nanowire showed up to 120% elongation and a 30% increase in diameter with a volume expansion of about 272%. The charging front, which separates the reacted and unreacted sections of the nanowire, contains a high density of mobile dislocations, which are continuously nucleated and annihilated at the moving reaction front. This dislocation cloud indicates large in-plane misfit stresses, and serves as structural precursor to the eventual complete solid-state amorphization. The rate of charging in our nanobatteries is found to be proportional to the inverse square root of nanowire length, indicating that a standalone nanobattery or integrated arrays of nanobatteries should have kinetic advantage over conventional battery design. The present observations also provide important mechanistic insights for the design of advanced batteries with improved performance and lifetime for broad electrical energy storage applications.

  13. Kinetics of colloidal gold nanoparticle chain assembly via in situ liquid cell electron microscopy observations

    NASA Astrophysics Data System (ADS)

    Woehl, Taylor; Prozorov, Tanya; Emergent Atomic; Magnetic Structures Team

    2014-11-01

    Various types of colloidal nanoparticles are known to self-assemble into hierarchical mesostructures via anisotropic interparticle interactions. Previous modeling and experiments have suggested that dipolar interactions may be responsible for assembly of one dimensional nanoparticle chain structures; however, due to a lack of in situobservations little is known about the kinetics of the self-assembly. Here we use real-time nanoscale observations to measure the self-assembly kinetics of colloidal gold nanoparticles into one dimensional chains. Gold nanoparticles suspended in acetate buffer were observed viain situ liquid electron microscopy to self-assemble into chains of 5--10 nanoparticles over a time of minutes. Self-assembly is initiated upon irradiation of the nanoparticles with the imaging electron beam. Measurements of the self-assembly kinetics revealed that the chains formed via second order aggregation kinetics during the first tens of seconds. We investigate the effects of the electron beam current and ionic strength of the buffer solution on the effective aggregation rate and chain formation mechanism. Our observations suggest that the aggregation rate increases with the effective diffusivity of the nanoparticles. T.P. acknowledges support from the Department of Energy Office of Science Early Career Research Award, Biomolecular Materials Program. This work was supported by the U.S. Department of Energy, Office of Basic Energy Science, Division of Materials Sciences.

  14. Using Lidar, in-situ measurements and Trajectory Analysis to observe air pollution in Beijing, 2014

    NASA Astrophysics Data System (ADS)

    Chen, Zhenyi; Liu, Wenqing; Liu, Jianguo; Zhang, Tianshu; Dong, Yunsheng

    2016-06-01

    We present combined Mie lidar, ozone lidar and wide-range particle spectrometer observations that were carried out in Beijing, north China during two periods—one haze period before the Asia-Pacific Economic Cooperation (APEC) meeting and one moderate pollution period during the meeting in 2014. High extinction coefficient, moderate ozone concentration and variable particle number concentration were obtained throughout the first haze observation period. The mean extinction coefficients in the two pollution periods were 0.52 km-1 and 0.23 km-1, respectively, at 532 nm. The ozone concentration during the first haze phase was more various with higher average value of 49 ppb compared to that in the second pollution observations (32 ppb). The comparison of aerosols and ozone in different heights indicate different pollution sources and complicated ozone process of generation and disappearance. The four-day back trajectories from a HYSPLIT model indicate that the air masses in the lower boundary layer were advected from the densely populated south regions of China and the long pollution transportation passing through northern China.

  15. MAPIR: An Airborne Polarmetric Imaging Radiometer in Support of Hydrologic Satellite Observations

    NASA Technical Reports Server (NTRS)

    Laymon, C.; Al-Hamdan, M.; Crosson, W.; Limaye, A.; McCracken, J.; Meyer, P.; Richeson, J.; Sims, W.; Srinivasan, K.; Varnevas, K.

    2010-01-01

    In this age of dwindling water resources and increasing demands, accurate estimation of water balance components at every scale is more critical to end users than ever before. Several near-term Earth science satellite missions are aimed at global hydrologic observations. The Marshall Airborne Polarimetric Imaging Radiometer (MAPIR) is a dual beam, dual angle polarimetric, scanning L band passive microwave radiometer system developed by the Observing Microwave Emissions for Geophysical Applications (OMEGA) team at MSFC to support algorithm development and validation efforts in support of these missions. MAPIR observes naturally-emitted radiation from the ground primarily for remote sensing of land surface brightness temperature from which we can retrieve soil moisture and possibly surface or water temperature and ocean salinity. MAPIR has achieved Technical Readiness Level 6 with flight heritage on two very different aircraft, the NASA P-3B, and a Piper Navajo.

  16. Evaluation of Nimbus 7 SMMR sensor with airborne radiometers and surface observations in the Norwegian Sea

    NASA Technical Reports Server (NTRS)

    Gloersen, P.; Cavalieri, D.; Crawford, J.; Campbell, W. J.; Farrelly, B.; Johannessen, J.; Johannessen, O. M.; Svendsen, E.; Kloster, K.

    1981-01-01

    Measurements made by the Nimbus 7 SMMR are compared with near simultaneous observations using the airborne SMMR simulator and with surface observations. The area of the test is in the Norwegian Sea between Bear Island and Northern Norway. It is noted that during the observation period two low-pressure systems were located in the test area, giving a spatial wind variation from 3-20 m/s. It is shown that the use of the currently available brightness temperatures and algorithms for SMMR does not give universally satisfactory results for SST and wind speed under extreme weather conditions. In addition, the SMMR simulator results are seen as indicating the need for more work on calibration.

  17. Multispectral Airborne Mapping LiDAR Observations of the McMurdo Dry Valleys

    NASA Astrophysics Data System (ADS)

    Fernandez Diaz, J. C.; Fountain, A. G.; Morin, P. J.; Singhania, A.; Hauser, D.; Obryk, M.; Shrestha, R. L.; Carter, W. E.; Sartori, M. P.

    2015-12-01

    Field observations have documented dramatic changes over the past decade in the McMurdo Dry Valleys of Antarctica: extreme river incisions, significant glacier loss, and the appearance of numerous thermokarst slumps. To date these observations have been sporadic and localized, and have not been able to capture change on a valley-wide scale. During the 2014-2015 Antarctic summer season, specifically between December 4th, 2014 and January 19th, 2015, we undertook a widescale airborne laser mapping campaign to collect a baseline digital elevation model for 3500 km2 area of the Dry Valleys and other areas of interest. The airborne LiDAR observations were acquired with a novel multi-spectral LiDAR sensor with active laser observations at three light wavelengths (532 nm, 1064 nm, and 1550 nm) simultaneously; which not only allowed the generation of a high resolution elevation model of the area, but also provides multispectral signatures for observed terrain features. In addition to the LiDAR data, high resolution (5-15 cm pixels) digital color images were collected. During the six week survey campaign of the Dry Valleys a total of 30 flights were performed, in which about 20 billion LiDAR returns and 21,000 60-Mpixels images were collected. The primary objective of this project is to perform a topographic change detection analysis by comparing the recently acquired dataset to a lower resolution dataset collected by NASA in the 2001-2002 season. This presentation will describe the processing and analysis of this significant mapping dataset and will provide some initial observations from the high resolution topography acquired.

  18. Intraannual variability of tides in the thermosphere from model simulations and in situ satellite observations

    NASA Astrophysics Data System (ADS)

    Häusler, K.; Hagan, M. E.; Forbes, J. M.; Zhang, X.; Doornbos, E.; Bruinsma, S.; Lu, G.

    2015-01-01

    In this paper, we provide insights into limitations imposed by current satellite-based strategies to delineate tidal variability in the thermosphere, as well as the ability of a state-of-the-art model to replicate thermospheric tidal determinations. Toward this end, we conducted a year-long thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) simulation for 2009, which is characterized by low solar and geomagnetic activity. In order to account for tropospheric waves and tides propagating upward into the ˜30-400 km model domain, we used 3-hourly MERRA (Modern-Era Retrospective Analysis for Research and Application) reanalysis data. We focus on exospheric tidal temperatures, which are also compared with 72 day mean determinations from combined Challenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) satellite observations to assess the model's capability to capture the observed tidal signatures and to quantify the uncertainties associated with the satellite exospheric temperature determination technique. We found strong day-to-day tidal variability in TIME-GCM that is smoothed out when averaged over as few as ten days. TIME-GCM notably overestimates the 72 day mean eastward propagating tides observed by CHAMP/GRACE, while capturing many of the salient features of other tidal components. However, the CHAMP/GRACE tidal determination technique only provides a gross climatological representation, underestimates the majority of the tidal components in the climatological spectrum, and moreover fails to characterize the extreme variability that drives the dynamics and electrodynamics of the ionosphere-thermosphere system. A multisatellite mission that samples at least six local times simultaneously is needed to provide this quantification.

  19. In-Situ TEM-STM Observations of SWCNT Ropes/Tubular Transformations

    NASA Technical Reports Server (NTRS)

    Sola, F.; Lebron-Colon, M.; Ferreira, P. J.; Fonseca, L. F.; Meador, M. A.; Marin, C.

    2010-01-01

    Single-walled carbon nanotubes (SWCNTs) prepared by the HiPco process were purified using a modified gas phase purification technique. A TEM-STM holder was used to study the morphological changes of SWCNT ropes as a function of applied voltage. Kink formation, buckling behavior, tubular transformation and eventual breakdown of the system were observed. The tubular formation was attributed to a transformation from SWCNT ropes to multi-walled carbon nanotube (MWCNT) structures. It is likely mediated by the patching and tearing mechanism which is promoted primarily by the mobile vacancies generated due to current-induced heating and, to some extent, by electron irradiation.

  20. Nanocrystal Diffusion in a Liquid Thin Film Observed by in situ Transmission Electron Microscopy

    SciTech Connect

    Zheng, Haimei; Claridge, Shelley A.; Minor, Andrew M.; Alivisatos, A. Paul; Dahmen, Ulrich

    2009-04-17

    We have directly observed motion of inorganic nanoparticles during fluid evaporation using a Transmission Electron Microscope. Tracking real-time diffusion of both spherical (5-15 nm) and rod-shaped (5x10 nm) gold nanocrystals in a thin-film of water-15percentglycerol reveals complex movements, such as rolling motions coupled to large-step movements and macroscopic violations of the Stokes-Einstein relation for diffusion. As drying patches form during the final stages of evaporation, particle motion is dominated by the nearby retracting liquid front.

  1. Envisaged in-situ plasma observations on comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Hilchenbach, Martin; Remizov, Anatoli; Auster, Hans-Ulrich

    2013-04-01

    In autumn2014, ESA's corner stone mission Rosetta will orbit comet 67P/Churyumov-Gerasimenko and deliver the cometary lander Philae onto the comet surface. The instrument ROMAP (Rosetta Lander Magnetometer and Plasma Monitor) onboard Philae consists of a fluxgate magnetometer, a plasma ion and an electron sensor. ROMAP will measure for the first time the magnetic field and the bulk plasma density, velocity and temperature on a cometary surface. We will discuss the determination of Philae surface attitude as derived from the solar wind velocity vector as well as the dawn to dusk plasma observations and their relevance for the nucleus regolith and dust grain charging.

  2. In-situ Observations of Mid-latitude Forest Fire Plumes Deep in the Stratosphere

    NASA Technical Reports Server (NTRS)

    Jost, Hans-Juerg; Drdla, Katja; Stohl, Andreas; Pfister, Leonhard; Loewenstein, Max; Lopez, Jimena P.; Hudson, Paula K.; Murphy, Daniel M.; Cziczo, Daniel J.; Fromm, Michael

    2004-01-01

    We observed a plume of air highly enriched in carbon monoxide and particles in the stratosphere at altitudes up to 15.8 km. It can be unambiguously attributed to North American forest fires. This plume demonstrates an extratropical direct transport path from the planetary boundary layer several kilometers deep into the stratosphere, which is not fully captured by large-scale atmospheric transport models. This process indicates that the stratospheric ozone layer could be sensitive to changes in forest burning associated with climatic warming.

  3. Sea level rise during past 40 years determined from satellite and in situ observations.

    PubMed

    Cabanes, C; Cazenave, A; Le Provost, C

    2001-10-26

    The 3.2 +/- 0.2 millimeter per year global mean sea level rise observed by the Topex/Poseidon satellite over 1993-98 is fully explained by thermal expansion of the oceans. For the period 1955-96, sea level rise derived from tide gauge data agrees well with thermal expansion computed at the same locations. However, we find that subsampling the thermosteric sea level at usual tide gauge positions leads to a thermosteric sea level rise twice as large as the "true" global mean. As a possible consequence, the 20th century sea level rise estimated from tide gauge records may have been overestimated.

  4. In Situ Spectroscopic Observation of Activation and Transformation of Tantalum Suboxides

    SciTech Connect

    Wang, Ke; Liu, Zhi; Cruz, Tirma Herranz; Salmeron, Miquel; Liang, Hong

    2009-12-16

    Using ambient pressure X-ray Photoelectron Spectroscopy (AP-XPS), we were able to observe the process of oxidation of tantalum with different morphological parameters. Being able to trace surface evolution during oxidation, we evaluated activation energy of oxidation under the influence of strain and grain boundaries. It was found that the metal oxidized through three different stages and there was a transition stage where the phase transformation from suboxides to the equilibrium state of pentoxide. The applied stress and surface defects reduced the activation energy oxidation.

  5. Remote sensing and in situ observations of marine slicks associated with inhomogeneous coastal currents

    NASA Astrophysics Data System (ADS)

    Ermakov, S.; Kapustin, I.; Sergievskaya, I.

    2011-11-01

    Field observations co-located and simultaneous with satellite radar imagery of biogenic slick bands on the sea surface aimed to study relation between slicks and marine stream currents were carried out in the coastal zone of the Black Sea. Measurements of the current velocities at different depths were performed using an acoustic Doppler current profiler (ADCP) and surface floats. Samples of surfactant films inside/outside slick bands were collected from the water surface with nets. The sampled films were reconstructed in laboratory conditions and measurements of the damping coefficient of gravity-capillary waves and the surface tension were carried out using an original parametric wave method. It is obtained that the banded slicks are characterized by enhanced concentration of surfactants due to their compression by convergent current components. The slicks are revealed to be oriented along the stream currents and are located in the zones of current shears. Small convergent transverse velocity components are observed near slick boundaries and are responsible for slick formation in stream shear currents. Different examples of slicks formed by stream shear current are described. Results of a case study of two streams of different directions merging and forming a banded slick in a shear zone with convergent transverse current components are presented. Another case study is when a flow below a thermocline coming to the shore meets a bottom slope and a vertical current occurs resulting in horizontal divergence and convergence on the surface.

  6. In situ observations of fish associated with coral reefs off Ireland

    NASA Astrophysics Data System (ADS)

    Söffker, M.; Sloman, K. A.; Hall-Spencer, J. M.

    2011-08-01

    The abundance and behaviour of fish on and around coral reefs at Twin Mounds and Giant Mounds, carbonate mounds located on the continental shelf off Ireland (600-1100 m), were studied using two Remotely Operated Vehicle (ROV) dives. We recorded 30 fish taxa on the dives, together with three species of Scleractinia ( Lophelia pertusa, Madrepora oculata and Desmophyllum cristagalli) and a diverse range of other corals (Antipatharia, Alcyonacea, and Stylasteridae). Stands of live coral provided the only habitat in which Guttigadus latifrons was observed whereas Neocyttus helgae was found predominantly on structural habitats provided by dead coral. Significantly more fish were found on structurally complex coral rubble habitats than on flatter areas where coral rubble was clogged with sand. The most common species recorded was Lepidion eques (2136 individuals), which always occurred a few cm above bottom and was significantly more active on the reefs than on sedimentary habitats. Synaphobranchus kaupii (1157 indiv.) , N. helgae (198 indiv.) and Micromesistius poutassou (116 indiv.) were also common; S. kaupii did not exhibit habitat-related differences in behaviour, whilst N. helgae was more active over the reefs and other structured habitats whereas M. poutassou was more active with decreasing habitat complexity. Trawl damage and abandoned fishing gear was observed at both sites. We conclude that Irish coral reefs provide complex habitats that are home to a diverse assemblage of fish utilising the range of niches occurring both above and within the reef structure.

  7. In-Situ Observations of Phase Transformations in the HAZ of 2205 Duplex Stainless Steel Weldments

    SciTech Connect

    Palmer, T A; Elmer, J W; Wong, J

    2001-08-15

    Ferrite ({delta})/austenite ({gamma}) transformations in the heat affected zone (HAZ) of a gas tungsten arc (GTA) weld in 2205 duplex stainless steel are observed in real-time using spatially resolved X-ray diffraction (SRXRD) with high intensity synchrotron radiation. A map showing the locations of the {delta} and {gamma} phases with respect to the calculated weld pool dimensions has been constructed from a series of SRXRD scans. Regions of liquid, completely transformed {gamma}, a combination of partially transformed {gamma} with untransformed {delta}, and untransformed {delta}+{gamma} are identified. Analysis of each SRXRD pattern provides a semi-quantitative definition of both the {delta}/{gamma} phase balance and the extent of annealing which are mapped for the first time with respect to the calculated weld pool size and shape. A combination of these analyses provides a unique real-time description of the progression of phase transformations in the HAZ. Using these real-time observations, important kinetic information about the transformations occurring in duplex stainless steels during heating and cooling cycles typical of welding can be determined.

  8. Escape of Pluto's Atmosphere: In Situ Measurements from New Horizons and Remote Observations from Chandra

    NASA Astrophysics Data System (ADS)

    McNutt, R. L., Jr.; Hill, M. E.; Kollmann, P.; Krimigis, S. M.; Brown, L. E.; Kusterer, M. B.; Lisse, C. M.; Mitchell, D. G.; Vandegriff, J. D.; McComas, D. J.; Bagenal, F.; Elliott, H. A.; Ennico Smith, K.; Horanyi, M.; Olkin, C.; Piquette, M. R.; Stern, A.; Strobel, D. F.; Szalay, J.; Valek, P. W.; Weaver, H. A., Jr.; Weidner, S.; Young, L. A.; Zirnstein, E.; Wolk, S. J.

    2015-12-01

    The escape rate of Pluto's atmosphere is of significant scientific interest. It is a Group 1 science goal of the New Horizons mission. In addition, a Group 3 science goal of the mission has been to characterize the energetic particle environment of the Pluto system. The Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) is a compact, energy by time-of-flight (TOF) instrument developed to address both of these science goals. Pluto is known to have an atmosphere, and current models postulate a majority N2 composition with free escape of up to ~1028 molecules/sec. This is very similar to the physical situation of a variety comets observed in the inner heliosphere. However, the gravitational field of Pluto exerts a significant effect on the escaping neutrals, unlike at a comet. The ionization of neutrals emitted from comets results in heavy ions, which are accelerated by the convective solar-wind electric field. The expected major ionization product near Pluto is singly ionized N2 molecules with pickup energies sufficient to be measured with PEPSSI. In the process of measuring the local energetic particle environment, such measurements will also provide constraints on the local density of Pluto's extended atmosphere, which, along with plasma measurements from the Solar Wind Around Pluto (SWAP) instrument also on New Horizons should allow the inference of the strengh and extent of mass-loading of the solar wind due to Pluto's atmosphere. Pluto's neutral atmosphere also provides a source population for charge exchange of highly ionized, minor ions in the solar wind, such as O, C, and N. This process allows these ions to capture one electron and be left in an excited state. That state, in turn decays with the emission of a low-energy (100 eV to 1 keV) X-ray, which can be detected at Earth. Such observations have been made of comets since the X-ray emission discovery in 1996 and used to infer cometary outgassing rates. Similar observatins have been made

  9. In situ observation of harmful dinoflagellate bloom in the eastern coast of Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hisashi; Murakami, Hirishi; Miyamura, Kazuyoshi; Siawanto, Eko; Kobayashi, Hiroshi; Ishizaka, Joji

    2014-05-01

    Oita coast, where is in the eastern coast of Kyushu, Japan, is a richly fish aquaculture area. However, sometimes harmful algal blooms occur in this region, especially harmful dinoflagellates blooms, and cultured fish mortality occurs. Ocean color remote sensing is expected as a useful tool to reduce the financial damage of harmful algal blooms. However, ocean color data is low accuracy in the coastal region because colored dissolved organic matter and suspended solid are dominant. More optical data of harmful algal blooms are required because there are few data in harmful algal blooms. The field observation was conducted to understand the inherent optical property of harmful dinoflagellate bloom in the eastern coast of Oita prefecture on April and August 2013. Chlorophyll-a maximum (>24 mg m^-3) was observed in the subsurface layer on April 2013. The dominant phytoplankton species in this chlorophyll-a maximum layer was dinoflagellate Cochlodinium polykrikoides (>300 cells ml^-1) and early stage of the bloom was formed. Peak of the remote sensing reflectance was near 565nm due to strong phytoplankton absorption within 400 ~ 500 nm domain from the subsurface bloom layer. Moreover, high phytoplankton absorption coefficient was observed at the shorter wavelength (< 400nm). This strong absorption might be due to mycosporine-like amino acids, which absorb the UV (Kahru and Mitchell, 1998). And this subsurface C. polykrikoides bloom was detected by using dinoflagellate bloom detection algorithm, which is a simpler new satellite remote sensing-based harmful algal blooms detection method for JAXA's GCOM-C/SGLI (Siswanto et al., 2013). However, detection of the dinoflagellate Karenia mikimotoi bloom by using the algorithm on August 2013 was difficult as colored dissolved organic matter and detritus absorptions were high. Although the algorithm could detect the early stage of C. polycrikoides bloom, the algorithm improvement to detect the harmful algal blooms in the case II

  10. In-situ observation of dynamic processes during organic semiconductor thin film deposition and strain-stabilization of metastable states

    NASA Astrophysics Data System (ADS)

    Li, Yang; Wan, Jing; Smilgies, Detlef-M.; Bouffard, Nicole; Sun, Richard; Headrick, Randall

    In-situ optical spectromicroscopy in reflection mode is used to study the growth mechanisms and thermal stability of 6,13- bis(trisopropylsilylethynyl)-pentacene (TIPS-pentacene) thin films. The results show that the films form in a supersaturated state before transforming to a solid film. Molecular aggregates are observed by optical spectroscopy in this supersaturated region corresponding to subcritical nuclei in the crystallization process. During deposition on a heated substrate, a progressive blue shift of optical absorption peaks of the solid film is observed at higher deposition temperatures due to a continuous thermally driven change of the crystalline packing. As crystalline films are cooled to ambient temperature they becomes strained although cracking of thicker films is observed, which allows the strain to partially relax. Below a critical thickness of 30 nm, cracking is not observed and the films are constrained to the lattice constants corresponding to the temperature at which they were deposited. An high averaged hole mobility about 2 cm2v-1s-1 is obtained for strained TIPS-pentacene thin films deposited at 135ûC.

  11. How Well Does the S-Web Theory Predict In-Situ Observations of the Slow Solar Wind?

    NASA Astrophysics Data System (ADS)

    Young, A. K.; Antiochos, S. K.; Linker, J.; Zurbuchen, T.

    2014-12-01

    The S-Web theory provides a physical explanation for the origin and properties of the slow solar wind, particularly its composition. The theory proposes that magnetic reconnection along topologically complex boundaries between open and closed magnetic fields on the sun releases plasma from closed magnetic field regions into the solar wind at latitudes away from the heliospheric current sheet. Such a wind would have elevated charge states compared to the fast wind and an elemental composition resembling the closed-field corona. This theory is currently being tested using time-dependent, high-resolution, MHD simulations, however comparisons to in-situ observations play an essential role in testing and understanding slow-wind release mechanisms. In order to determine the relationship between S-Web signatures and the observed, slow solar wind, we compare plasma data from the ACE and Ulysses spacecraft to solutions from the steady-state models created at Predictive Science, Inc., which use observed magnetic field distributions on the sun as a lower boundary condition. We discuss the S-Web theory in light of our results and the significance of the S-Web for interpreting current and future solar wind observations. This work was supported, in part, by the NASA TR&T and SR&T programs.

  12. Coupling between creep and redox behavior in nickel - yttria stabilized zirconia observed in-situ by monochromatic neutron imaging

    NASA Astrophysics Data System (ADS)

    Makowska, Malgorzata Grazyna; Kuhn, Luise Theil; Frandsen, Henrik Lund; Lauridsen, Erik Mejdal; De Angelis, Salvatore; Cleemann, Lars Nilausen; Morgano, Manuel; Trtik, Pavel; Strobl, Markus

    2017-02-01

    Ni-YSZ (nickel - yttria stabilized zirconia) is a material widely used for electrodes and supports in solid oxide electrochemical cells. The mechanical and electrochemical performance of these layers, and thus the whole cell, depends on their microstructure. During the initial operation of a cell, NiO is reduced to Ni. When this process is conducted under external load, like also present in a stack assembly, significant deformations of NiO/Ni-YSZ composite samples are observed. The observed creep is orders of magnitude larger than the one observed after reduction during operation. This phenomenon is referred to as accelerated creep and is expected to have a significant influence on the microstructure development and stress field present in the Ni-YSZ in solid oxide electrochemical cells (SOCs), which is highly important for the durability of the SOC. In this work we present energy selective neutron imaging studies of the accelerated creep phenomenon in Ni/NiO-YSZ composite during reduction and also during oxidation. This approach allowed us to observe the phase transition and the creep behavior simultaneously in-situ under SOC operation-like conditions.

  13. Evaluation of long-term surface-retrieved cloud droplet number concentration with in situ aircraft observations

    NASA Astrophysics Data System (ADS)

    Lim, Kyo-Sun Sunny; Riihimaki, Laura; Comstock, Jennifer M.; Schmid, Beat; Sivaraman, Chitra; Shi, Yan; McFarquhar, Greg M.

    2016-03-01

    A new operational retrieval of cloud droplet number concentration (ND) at cloud base has been produced from surface remote sensors at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site for 13 years from January 1998 to January 2011. The retrieval is based on surface radiometer measurements of cloud optical depth from the multifilter rotating shadow band radiometer and liquid water path from the microwave radiometer (MWR). It is only applicable for single-layered overcast warm (stratus or stratocumulus) clouds. Evaluation with in situ aircraft measurements during the extended-term aircraft field campaign, Routine ARM Aerial Facility (AAF) Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO), shows that the retrieved ND robustly reproduces the primary mode of the in situ measured probability density function (PDF) but produces too wide a distribution, primarily caused by frequent high cloud dropl