Science.gov

Sample records for airborne radiation measurements

  1. Spectral aerosol direct radiative forcing from airborne radiative measurements during CalNex and ARCTAS

    NASA Astrophysics Data System (ADS)

    Leblanc, Samuel E.; Schmidt, K. S.; Pilewskie, P.; Redemann, J.; Hostetler, C.; Ferrare, R.; Hair, J.; Langridge, J. M.; Lack, D. A.

    2012-09-01

    This study presents the aerosol radiative forcing derived from airborne measurements of shortwave spectral irradiance during the 2010 Research at the Nexus of Air Quality and Climate Change (CalNex). Relative forcing efficiency, the radiative forcing normalized by aerosol optical thickness and incident irradiance, is a means of comparing the aerosol radiative forcing for different conditions. In this study, it is used to put the aerosol radiative effects of an air mass in the Los Angeles basin in context with case studies from three field missions that targeted other regions and aerosol types, including a case study from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS). For CalNex, we relied on irradiance measurements onboard the NOAA P-3 aircraft during a flight on 19 May 2010 over a ground station. CalNex presented a difficulty for determining forcing efficiency since one of the input parameters, optical thickness, was not available from the same aircraft. However, extinction profiles were available from a nearby aircraft. An existing retrieval algorithm was modified to use those measurements as initial estimate for the missing optical thickness. In addition, single scattering albedo and asymmetry parameter (secondary products of the method), were compared with CalNex in situ measurements. The CalNex relative forcing efficiency spectra agreed with earlier studies that found this parameter to be constrained at each wavelength within 20% per unit of aerosol optical thickness at 500 nm regardless of aerosol type and experiment, except for highly absorbing aerosols sampled near Mexico City. The diurnally averaged below-layer forcing efficiency integrated over the wavelength range of 350-700 nm for CalNex is estimated to be -58.6 ± 13.8 W/m2, whereas for the ARCTAS case it is -48.7 ± 11.5 W/m2.

  2. Airborne gamma radiation measurements of soil moisture during FIFE: Activities and results

    NASA Technical Reports Server (NTRS)

    Peck, Eugene L.

    1992-01-01

    Soil moisture measurements were obtained during the summer of 1987 and 1989 near Manhattan, Kansas, using the National Weather Service (NWS) airborne gamma radiation system. A network of 24 flight lines were established over the research area. Airborne surveys were flown daily during two intensive field campaigns. The data collected was sufficient to modify the NWS standard operational method for estimating soil moisture for the Field Experiment (FIFE) flight lines. The average root mean square error of the soil moisture estimates for shorter FIFE flight lines was found to be 2.5 percent, compared with a reported value of 3.9 percent for NWS flight lines. Techniques were developed to compute soil moisture estimates for portions of the flight lines. Results of comparisons of the airborne gamma radiation soil moisture estimates with those obtained using the NASA Pushbroom Microwave Radiation (PBMR) system and hydrological model are presented. The airborne soil moisture measurements, and real averages computed using all remotely sensed and ground data, have been in support of the research of the many FIFE investigators whose overall goal was the upscale integration of models and the application of satellite remote sensing.

  3. Radiative flux measurements during the Airborne Tropical Tropopause Experiment (ATTREX) Guam Deployment.

    NASA Astrophysics Data System (ADS)

    Kindel, B. C.; Pilewskie, P.; Schmidt, S.

    2015-12-01

    The Airborne Tropical Tropopause Experiment was a field program utilizing the NASA Global Hawk aircraft, to make extensive measurements of tropical tropopause layer (TTL) over the Pacific Ocean. In February and March of 2014, the NASA Global Hawk was deployed to Guam and flew six long duration science flights. The aircraft was outfitted with a suite of instruments to study the composition of the TTL. Measurements included: water vapor amount, cloud particle size and shape, various gaseous species (e.g. CO, CH4, CO2, O3), and radiation measurements. The radiation measurements were comprised of the Solar Spectral Flux Radiometer (SSFR) that made spectrally resolved measurements of upwelling and downwelling solar irradiance from 350 to 2200 nm and thermal broadband (4μm to 42 μm) upwelling and downwelling irradiance. Once airborne, the Global Hawk made numerous vertical profiles (14 - 18 km) through the TTL. In this work we present results of combined solar spectral irradiance and broadband thermal irradiance measurements. Solar spectral measurements are correlated, wavelength-by-wavelength, with broadband thermal measurements. The radiative impact in the TTL of water vapor and cirrus clouds are examined both in the solar and thermal wavelengths from both upwelling and downwelling irradiances. The spectral measurements are used in an attempt to attribute physical mechanisms to the thermal (spectrally integrated) measurements. Measurements of heating rates are also presented, highlighting the difficultly in obtaining reliable results from aircraft measurements.

  4. A new measurement method for separating airborne and structureborne noise radiated by aircraft type panels

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1982-01-01

    The theoretical basis for and experimental validation of a measurement method for separating airborne and structure borne noise radiated by aircraft type panels are presented. An extension of the two microphone, cross spectral, acoustic intensity method combined with existing theory of sound radiation of thin shell structures of various designs, is restricted to the frequency range below the coincidence frequency of the structure. Consequently, the method lends itself to low frequency noise problems such as propeller harmonics. Both an aluminum sheet and two built up aircraft panel designs (two aluminum panels with frames and stringers) with and without added damping were measured. Results indicate that the method is quick, reliable, inexpensive, and can be applied to thin shell structures of various designs.

  5. Radiative Characteristics of Clouds Embedded in Smoke Derived from Airborne Multiangular Measurements

    NASA Technical Reports Server (NTRS)

    Gautam, Ritesh; Gatebe, Charles K.; Singh, Manoj; Varnai, Tamas; Poudyal, Rajesh

    2016-01-01

    Clouds in the presence of absorbing aerosols result in their apparent darkening, observed at the top of atmosphere (TOA), which is associated with the radiative effects of aerosol absorption. Owing to the large radiative effect and potential impacts on regional climate, above-cloud aerosols have recently been characterized in multiple satellite-based studies. While satellite data are particularly useful in showing the radiative impact of above-cloud aerosols at the TOA, recent literature indicates large uncertainties in satellite retrievals of above-cloud aerosol optical depth (AOD) and single scattering albedo (SSA), which are among the most important parameters in the assessment of associated radiative effects. In this study, we analyze radiative characteristics of clouds in the presence of wildfire smoke using airborne data primarily from NASA's Cloud Absorption Radiometer, collected during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites campaign in Canada during the 2008 summer season. We found a strong positive reflectance (R) gradient in the UV-visible (VIS)-near infrared (NIR) spectrum for clouds embedded in dense smoke, as opposed to an (expected) negative gradient for cloud-free smoke and a flat spectrum for smoke-free cloud cover. Several cases of clouds embedded in thick smoke were found, when the aircraft made circular/spiral measurements, which not only allowed the complete characterization of angular distribution of smoke scattering but also provided the vertical distribution of smoke and clouds (within 0.5-5 km). Specifically, the largest darkening by smoke was found in the UV/VIS, with R(sub 0.34 microns) reducing to 0.2 (or 20%), in contrast to 0.8 at NIR wavelengths (e.g., 1.27 microns). The observed darkening is associated with large AODs (0.5-3.0) and moderately low SSA (0.85-0.93 at 0.53 microns), resulting in a significantly large instantaneous aerosol forcing efficiency of 254 +/- 47 W/sq m/t. Our

  6. Radiative characteristics of clouds embedded in smoke derived from airborne multiangular measurements

    NASA Astrophysics Data System (ADS)

    Gautam, Ritesh; Gatebe, Charles K.; Singh, Manoj K.; Várnai, Tamás.; Poudyal, Rajesh

    2016-08-01

    Clouds in the presence of absorbing aerosols result in their apparent darkening, observed at the top of atmosphere (TOA), which is associated with the radiative effects of aerosol absorption. Owing to the large radiative effect and potential impacts on regional climate, above-cloud aerosols have recently been characterized in multiple satellite-based studies. While satellite data are particularly useful in showing the radiative impact of above-cloud aerosols at the TOA, recent literature indicates large uncertainties in satellite retrievals of above-cloud aerosol optical depth (AOD) and single scattering albedo (SSA), which are among the most important parameters in the assessment of associated radiative effects. In this study, we analyze radiative characteristics of clouds in the presence of wildfire smoke using airborne data primarily from NASA's Cloud Absorption Radiometer, collected during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites campaign in Canada during the 2008 summer season. We found a strong positive reflectance (R) gradient in the UV-visible (VIS)-near infrared (NIR) spectrum for clouds embedded in dense smoke, as opposed to an (expected) negative gradient for cloud-free smoke and a flat spectrum for smoke-free cloud cover. Several cases of clouds embedded in thick smoke were found, when the aircraft made circular/spiral measurements, which not only allowed the complete characterization of angular distribution of smoke scattering but also provided the vertical distribution of smoke and clouds (within 0.5-5 km). Specifically, the largest darkening by smoke was found in the UV/VIS, with R0.34μm reducing to 0.2 (or 20%), in contrast to 0.8 at NIR wavelengths (e.g., 1.27 µm). The observed darkening is associated with large AODs (0.5-3.0) and moderately low SSA (0.85-0.93 at 0.53 µm), resulting in a significantly large instantaneous aerosol forcing efficiency of 254 ± 47 W m-2 τ-1. Our observations of smoke

  7. Airborne instruments to measure atmospheric aerosol particles, clouds and radiation: A cook's tour of mature and emerging technology

    NASA Astrophysics Data System (ADS)

    Baumgardner, D.; Brenguier, J. L.; Bucholtz, A.; Coe, H.; DeMott, P.; Garrett, T. J.; Gayet, J. F.; Hermann, M.; Heymsfield, A.; Korolev, A.; Krämer, M.; Petzold, A.; Strapp, W.; Pilewskie, P.; Taylor, J.; Twohy, C.; Wendisch, M.; Bachalo, W.; Chuang, P.

    2011-10-01

    An overview is presented of airborne systems for in situ measurements of aerosol particles, clouds and radiation that are currently in use on research aircraft around the world. Description of the technology is at a level sufficient for introducing the basic principles of operation and an extensive list of references for further reading is given. A number of newer instruments that implement emerging technology are described and the review concludes with a description of some of the most important measurement challenges that remain. This overview is a synthesis of material from a reference book that is currently in preparation and that will be published in 2012 by Wiley.

  8. Aerosol Spectral Radiative Forcing Efficiency from Airborne Measurements During Multiple Field Missions

    NASA Astrophysics Data System (ADS)

    Schmidt, S.; Leblanc, S. E.; Pilewskie, P.; Redemann, J.; Hostetler, C. A.; Ferrare, R. A.; Hair, J. W.

    2012-12-01

    Measurements of shortwave spectral irradiance in conjunction with measurements of aerosol optical depth are used to determine the direct aerosol radiative forcing for various different regions and missions. To better compare cases with different air masses and solar geometry, we use the concept of top-of-layer and bottom-of-layer relative forcing efficiency. The aerosol layers were sampled from aircraft during several field campaigns, including the Megacity Initiative: Local and Global Research Observations (MILAGRO, Mexico, 2006); the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS, Alaska and Alberta, 2008), Research at the Nexus of Air Quality and Climate Change (CalNex, California, 2010); and the Deep Convective Clouds and Chemistry Experiment (DC3, central US, 2012). We show that the spectral shape of the relative forcing efficiency is similar for these aerosol layers regardless of the aerosol type. The spectral relative forcing efficiency at any one wavelength for the majority of the cases is constrained within a span of 20% per unit of midvisible aerosol optical depth. Single scattering albedo, asymmetry parameter, and surface albedo are secondary products for the various methods used to determine aerosol radiative forcing. Using these, we determine the diurnally averaged spectral and broadband top-of-atmosphere and surface radiative forcing efficiency for the various different aerosol types and surface conditions.

  9. AIRBORNE RADIATION DETECTOR

    DOEpatents

    Cartmell, T.R.; Gifford, J.F.

    1959-08-01

    An ionization chamber used for measuring the radioactivity of dust present in atmospheric air is described. More particularly. the patent describes a device comprising two concentric open ended, electrically connected cylinders between which is disposed a wire electrcde. A heating source is disposed inside of the cylinder to circulate air through the space between the two cylinders by convective flow. A high voltage electric field between the wire electrcde of the electrically connected cylinder will cause ionization of the air as it passes therethrough.

  10. 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.

  11. Airborne measurements of spectral direct aerosol radiative forcing in INTEX/ICARTT (2004) and comparisons to previous campaigns

    NASA Astrophysics Data System (ADS)

    Redemann, J.; Pilewskie, P.; Russell, P.; Livingston, J.; Howard, S.; Schmid, B.; Pommier, J.; Gore, W.; Eilers, J.; Wendisch, M.; Bush, B.; Valero, F.

    2005-12-01

    As part of the INTEX-NA (INtercontinental chemical Transport EXperiment-North America) and ITCT (Intercontinental Transport and Chemical Transformation of anthropogenic pollution) field studies, the NASA Ames 14-channel Airborne Tracking Sunphotometer (AATS-14) and a pair of Solar Spectral Flux Radiometers (SSFR) took measurements from aboard a Jetstream 31 (J31) aircraft during 19 science flights (~ 53 flight hours) over the Gulf of Maine between 12 July and 8 August 2004. AATS-14 measures the direct solar beam transmission at 14 discrete wavelengths (354-2138 nm), yielding aerosol optical depth (AOD) spectra, while the SSFR system yields down- and upwelling solar irradiance at a spectral resolution of ~ 8-12 nm over the wavelength range 300-1700 nm. The combination of simultaneous AATS and SSFR measurements yields plots of net spectral irradiance as a function of aerosol optical depth as measured along horizontal flight legs. From the slope of these plots we determine the instantaneous aerosol-induced change in net radiative flux per change in AOD. By normalization to an aerosol optical depth change of unity we derive the spectral aerosol radiative forcing efficiency [W m-2 nm-1]. Numerical integration of the irradiance measurements over a given spectral range yields the broadband aerosol radiative forcing efficiency [W m-2]. In INTEX/ITCT, we observed a total of 16 horizontal AOD gradients, with 10 gradients well suited for our analysis because of the small changes in solar zenith angle. Within the 10 case studies we found a high variability in the derived instantaneous aerosol forcing efficiencies for the visible wavelength range (350-700 nm), with a mean of -79.6 W m-2 and a standard deviation of 21.8 W m-2 (27%). The mean instantaneous forcing efficiency for the visible plus near-IR wavelength range (350-1670 nm) was derived to be 135.3 W m-2 with a standard deviation of 36.0 W m-2 (27%). An analytical conversion of the instantaneous forcing efficiencies to

  12. Comparison of ground-based measurements of natural radiation to airborne radiation survey data on transects from coastal California to the Colorado Plateau

    NASA Astrophysics Data System (ADS)

    Stoffer, P. W.; Hernández, L.; Messina, P.; Dearaujo, J.; Li, A.; Hicks, A.; White, L.

    2008-12-01

    Natural gamma radiation measurements were collected with a hand-held Geiger counter at nearly 400 locations on two general transects across the southwestern United States. The data are used to provide ground-truth comparison to published airborne radiation surveys of the region. The first transect was collected by high school students in the SF-ROCKS program at San Francisco State University in the summer of 2008 starting in San Francisco. Data were collected across the Sierra Nevada Range on I-80, and across Highway 50 in Nevada, and I-70 in Utah. Data were collected in and around Great Basin, Arches, Capitol Reef, Bryce, and Zion National Parks, and Grand Staircase-Escalante National Monument. A second transect extends from San José, California to Flagstaff, Arizona and includes the Mojave National Reserve, Death Valley region, and locations throughout the Navajo Reservation region in northern Arizona and western New Mexico. Radiation data (with GPS reference) were collected from all the major sedimentary rock formations and igneous rocks of the Colorado Plateau and from many igneous and metamorphic rocks throughout the Great Basin and southern California deserts. Anomalously high localized levels were noted in selected sedimentary units associated with uranium exploration targets in the Colorado Plateau region, and in caverns and rock fissures where radon gas (and accumulation of derivative fission products) are the inferred sources.

  13. Airborne measurements of solar and planetary near ultraviolet radiation during the NASA/ESA CV-900 spacelab simulation

    NASA Technical Reports Server (NTRS)

    Sivjee, G. G.

    1977-01-01

    Results from a comparative study of the feasibility of employing experiment operators on the space shuttle to acquire scientifically worthwhile data are presented. The experiments performed during these tests included spectral observations of the Sun and Venus in the near ultraviolet region. The solar measurements were analyzed to determine ozone abundance in the terrestrial atmosphere. Using a detailed spectral matching technique to compare airborne solar UV measurements with synthetic spectral profiles of sunlight, it is deduced that in winter the total atmospheric ozone abundance is about 0.33 atm/cm at midlatitudes in the northern hemisphere.

  14. Airborne Coarse Mode Aerosol Measurements with the CAS-DPOL Instrument: Effects of Particle Shape and Refractive Index and Implications for Radiative Transfer Estimate

    NASA Astrophysics Data System (ADS)

    Sauer, D. N.; Weinzierl, B.; Gasteiger, J.; Spanu, A.; Freudenthaler, V.; Gross, S.

    2015-12-01

    Each year huge amounts of mineral dust are mobilized in deserts and arid regions of the world and transported over large distances forming thick elevated aerosol layers with a substantial fraction of coarse mode particles. Optical properties of mineral dust, including the absorptive refractive index of some components, cause a significant effect on the atmospheric radiative energy balance from optical to infrared wavelengths. The aerosol characteristics, in particular its coarse mode size distribution, are modified during long-range transport by aging and deposition processes. This also affects the aerosol optical properties and therefore the effect on the atmospheric radiative energy budget. In-situ measurements of aerosol microphysical properties are essential to characterize those effects in order to be implemented in global climate models in parametrized form. However, in-situ measurements of airborne coarse mode aerosols such as mineral dust and volcanic ash are challenging and the measurements are usually affected by substantial uncertainties. In this work we use airborne measurements of mineral dust from our optical light-scattering spectrometer CAS-DPOL during SALTRACE 2013 to discuss the analysis of such data. We cover the effects of varying refractive index and particle shapes and develop recommendations for the configuration of the CAS-DPOL for aerosol studies. We also present an inversion method to derive coarse mode size distributions from light-scattering probes for mixtures of non-spherical, absorbing aerosols. The size distributions retrieved from the in-situ measurements are then validated using an independent analysis with a combination of sun-photometer and lidar data. We apply these methods to investigate the Saharan mineral dust particle size distributions measured on both sides of the Atlantic Ocean and discuss the influence of aerosol aging on the atmospheric radiative energy budget. With this example we also assess how the uncertainties

  15. Operation Sun Beam, Shots Little Feller II and Small Boy. Project Officer's report - Project 7. 16. Airborne E-field radiation measurements of electromagnetic-pulse phenomena

    SciTech Connect

    Butler, K.L.

    1985-09-01

    Airborne measurements of the absolute vertical electric field (E-field) of the radiated electromagnetic pulse were attempted for Shots Little Feller II and Small Boy. Instrumentation included calibrated vertical whip antennas, wideband magnetic tape recorders, and photographs of oscilloscope traces. One instrumented aircraft participated in Little Feller II (C-131F); two aircraft participated in Small Boy (a C-131F and an A-3A). No detectable signals were recorded for either event. It is concluded that the vertical E-field intensities encountered were below the calibrated levels of the instrumentation or the method of instrumentation and calibration was inadequate for nonrepetitive pulse signals.

  16. Airborne radionuclides and radiation in buildings: a review.

    PubMed

    Nero, A V

    1983-08-01

    This paper reviews the literature on sources and measurement of natural airborne radionuclides and radiation in buildings. It also briefly reviews control measures and suggests areas for further research. The major emphasis is given to 222Rn and its daughters, since they typically cause the largest organ dose to the general population, most of which arises from indoor exposures. The indoor radiation field from radionuclides fixed in building materials and soil is also given substantial treatment.

  17. A note on the effect of reflected solar radiation on airborne and ground measurements in the thermal infrared

    NASA Technical Reports Server (NTRS)

    Whitehead, V. S.

    1971-01-01

    The magnitude of thermal solar radiation reflected from water surfaces is considered. It is shown both theoretically and by field observation that, for instruments with small fields of view, the reflected thermal solar radiation can contribute significantly to the measured energy. Comparison of thermal scanner data taken from aircraft at a 16 deg azimuth angle from the mirror point of the sun over the open ocean with data taken at a 164 deg anzimuth angle from the mirror point of the sun at the same angle from nadir is indicative of a difference of 2.8 K in the equivalent black body radiation temperature. Observations taken from a surface vessel into sunglint 80 deg from nadir are indicative of an equivalent black body radiation temperature that is 34 K warmer than the temperature obtained at a similar nadir angle away from the sunglint.

  18. Simulation and analysis of airborne antenna radiation patterns

    NASA Astrophysics Data System (ADS)

    Kim, J. J.; Burnside, Walter D.

    1984-12-01

    The objective is to develop an accurate and efficient analytic solution for predicting high frequency radiation patterns of fuselage-mounted airborne antennas. This is an analytic study of airborne antenna patterns using the Uniform Geometrical Theory of Diffraction (UTD). The aircraft is modeled in its most basic form so that the solution is applicable to general-type aircraft. The fuselage is modeled as a perfectly conducting composite ellipsoid; whereas, the wings, stabilizers, nose, fuel tanks, and engines, are simulated as perfectly conducting flat plates that can be attached to the fuselage and/or to each other. The composite-ellipsoid fuselage model is necessary to successfully simulate the wide variety of real world fuselage shapes. Since the antenna is mounted on the fuselage, it has a dominant effect on the resulting radiation pattern so it must be simulated accurately, especially near the antenna. Various radiation patterns are calculated for commercial, private, and military aircraft, and the Space Shuttle Orbiter. The application of this solution to numerous practical airborne antenna problems illustrates its versatility and design capability. In most cases, the solution accuracy is verified by the comparisons between the calculated and measured data.

  19. Simulation and analysis of airborne antenna radiation patterns

    NASA Astrophysics Data System (ADS)

    Kim, J. J. G.

    An accurate and efficient analytic solution for predicting high frequency radiation patterns of fuselage-mounted airborne antennas is described. This is an analytic study of airborne antenna patterns using the Uniform Geometrical Theory of Diffraction (UTD). The aircraft is modelled in its most basic form so that the solution is applicable to general-type aircraft. The fuselage is modelled as a perfectly conducting composite ellipsoid; whereas, the wings, stabilizers, nose, fuel tanks, and engines, etc., are simulated as perfectly conducting flat plates that can be attached to the fuselage and/or to each other. The composite-ellipsoid fuselage model is necessary to successfully simulate the wide variety of real world fuselage shapes. Since the antenna is mounted on the fuselage, it has a dominant effect on the resulting radiation pattern so it must be simulated accurately, especially near the antenna. Various radiation patterns are calculated for commercial, private, and military aircraft, and the space shuttle Orbiter. The application of this solution to numerous practical airborne antenna problems illustrates its versatility and design capability. In most cases, the solution accuracy is verified by the comparisons between the calculated and measured data.

  20. Simulation and analysis of airborne antenna radiation patterns

    NASA Technical Reports Server (NTRS)

    Kim, J. J.; Burnside, Walter D.

    1984-01-01

    The objective is to develop an accurate and efficient analytic solution for predicting high frequency radiation patterns of fuselage-mounted airborne antennas. This is an analytic study of airborne antenna patterns using the Uniform Geometrical Theory of Diffraction (UTD). The aircraft is modeled in its most basic form so that the solution is applicable to general-type aircraft. The fuselage is modeled as a perfectly conducting composite ellipsoid; whereas, the wings, stabilizers, nose, fuel tanks, and engines, are simulated as perfectly conducting flat plates that can be attached to the fuselage and/or to each other. The composite-ellipsoid fuselage model is necessary to successfully simulate the wide variety of real world fuselage shapes. Since the antenna is mounted on the fuselage, it has a dominant effect on the resulting radiation pattern so it must be simulated accurately, especially near the antenna. Various radiation patterns are calculated for commercial, private, and military aircraft, and the Space Shuttle Orbiter. The application of this solution to numerous practical airborne antenna problems illustrates its versatility and design capability. In most cases, the solution accuracy is verified by the comparisons between the calculated and measured data.

  1. Airborne measurements of spectral direct aerosol radiative forcing in the Intercontinental chemical Transport Experiment/Intercontinental Transport and Chemical Transformation of anthropogenic pollution, 2004

    NASA Astrophysics Data System (ADS)

    Redemann, Jens; Pilewskie, Peter; Russell, Philip B.; Livingston, John M.; Howard, Steve; Schmid, Beat; Pommier, John; Gore, Warren; Eilers, James; Wendisch, Manfred

    2006-07-01

    As part of the INTEX-NA (Intercontinental chemical Transport Experiment-North America) and ITCT (Intercontinental Transport and Chemical Transformation of anthropogenic pollution) field studies, the NASA Ames 14-channel Airborne Tracking Sunphotometer (AATS-14) and a pair of Solar Spectral Flux Radiometers (SSFR) took measurements from aboard a Sky Research Jet stream 31 (J31) aircraft during 19 science flights over the Gulf of Maine during 12 July to 8 August 2004. The combination of coincident AATS-14 and SSFR measurements yields plots of net (downwelling minus upwelling) spectral irradiance as a function of aerosol optical depth (AOD) as measured along horizontal flight legs. By definition, the slope of these plots yields the instantaneous change in net irradiance per unit AOD change and is referred to as the instantaneous spectral aerosol radiative forcing efficiency, Ei (W m-2 nm-1). Numerical integration over a given spectral range yields the instantaneous broadband aerosol radiative forcing efficiency (W m-2). This technique for deriving Ei is called the aerosol gradient method. Within 10 case studies considered suitable for our analysis we found a high variability in the derived instantaneous aerosol forcing efficiencies for the visible wavelength range (350-700 nm), with a mean of -79.6 W m-2 and a standard deviation of 21.8 W m-2 (27%). An analytical conversion of the instantaneous forcing efficiencies to 24-hour-average values yielded -45.8 ± 13.1 W m-2 (mean ± std). We present spectrally resolved aerosol forcing efficiencies between 350 and 1670 nm, estimates of the midvisible aerosol single scattering albedo and a comparison of observed broadband forcing efficiencies to previously reported values.

  2. Radiative heating rates during AAOE and AASE. [Airborne Antarctic Ozone Experiment and Airborne Arctic Stratospheric Experiment

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.

    1990-01-01

    Radiative transit computations of heating rates utilizing data from the 1987 Airborne Antarctic Ozone Experiment (AAOE) (Tuck et al., 1989) and the 1989 Airborne Arctic Stratospheric Experiment (AASE) (Turco et al., 1990) are described. Observed temperature and ozone profiles and a radiative transfer model are used to compute the heating rates for the Southern Hemisphere during AAOE and the Northern Hemisphere during AASE. The AASE average cooling rates computed inside the vortex are in good agreement with the diabatic cooling rates estimated from the ER-2 profile data for N2O for the AASE period (Schoeberl et al., 1989).

  3. Validation of Airborne CO2 Laser Measurements

    NASA Astrophysics Data System (ADS)

    Browell, E. V.; Dobler, J. T.; Kooi, S.; Fenn, M. A.; Choi, Y.; Vay, S. A.; Harrison, F. W.; Moore, B.; Zaccheo, T. S.

    2010-12-01

    This paper discusses the flight test validation of a unique, multi-frequency, intensity-modulated, single-beam laser absorption spectrometer (LAS) that operates near 1.57 μm for remote column CO2 measurements. This laser system is under development for a future space-based mission to determine the global distribution of regional-scale CO2 sources and sinks, which is the objective of the NASA Active Sensing of CO2 Emissions during Nights, Days, and Seasons (ASCENDS) mission. A prototype of this LAS system, called the Multi-frequency Fiber Laser Lidar (MFLL), was developed by ITT, and it has been flight tested in nine airborne campaigns since May 2005. This paper focuses on the most recent results obtained over the last two years of flight-testing where the MFLL remote CO2 column measurements were evaluated against airborne in situ CO2 profile measurements traceable to World Meteorological Organization standards. A comprehensive multiple-aircraft flight test program was conducted over Oklahoma and Virginia in July-August 2009. The MFLL obtained surface reflectance and average CO2 column variations along the 50-km flight legs over the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Central Facility (CF) in Lamont, Oklahoma; over rural Virginia and North Carolina; and over the Chesapeake Bay. For a flight altitude of 4.6 km, the average signal to noise ratio (SNR) for a 1-s CO2 column measurement was found to be 760, which is the equivalent of a CO2 mixing ratio precision of 0.60 ppmv, and for a 10-s average the SNR was found to be 2002 or 0.20 ppmv. Absolute comparisons of MFLL-derived and in situ-derived CO2 column measurements were made for all daytime flights conducted over Oklahoma and Virginia with an average agreement to within 0.32 ppmv. A major ASCENDS flight test campaign was conducted using the NASA DC-8 during 6-18 July 2010. The MFLL system and associated in situ CO2 instrumentation were operated on DC-8 flights over the Central Valley

  4. Airborne Wind Measurements at Cape Blanco, Oregon.

    SciTech Connect

    Lin, Jung-Tai Lin; Veenhuizen, Scott D.

    1983-12-01

    The airborne wind measuring system using a fixed wing airplane and a Loran-C navigation unit was proven to be feasible to provide the large scale background wind flow for initialization of numerical wind modeling. The rms errors in the airborne wind measuring system were +- 2 mph in wind speed and +- 12 degrees in wind direction. The advantages of this method were that wind speeds over a large area (5 miles x 14 miles, or 18 miles x 30 miles) may be determined rapidly, economically and at altitudes above the normal altitudes of TALA kite mesurements. The disadvantages were that the spatial resolution of the measurements was poor and near surface measurements were not feasible using a fixed wing aircraft. 1 reference, 10 figures, 1 table.

  5. BOREAS RSS-12 Airborne Tracking Sunphotometer Measurements

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Lobitz, Brad; Spanner, Michael; Wrigley, Robert

    2000-01-01

    The BOREAS RSS-12 team collected both ground and airborne sunphotometer measurements for use in characterizing the aerosol optical properties of the atmosphere during the BOREAS data collection activities. These measurements are to be used to: 1) measure the magnitude and variability of the aerosol optical depth in both time and space; 2) determine the optical properties of the boreal aerosols; and 3) atmospherically correct remotely sensed data acquired during BOREAS. This data set contains airborne tracking sunphotometer data that were acquired from the C-130 aircraft during its flights over the BOREAS study areas. The data cover selected days and times from May to September 1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  6. Airborne Atmospheric Aerosol Measurement System

    NASA Astrophysics Data System (ADS)

    Ahn, K.; Park, Y.; Eun, H.; Lee, H.

    2015-12-01

    It is important to understand the atmospheric aerosols compositions and size distributions since they greatly affect the environment and human health. Particles in the convection layer have been a great concern in global climate changes. To understand these characteristics satellite, aircraft, and radio sonde measurement methods have usually been used. An aircraft aerosol sampling using a filter and/or impactor was the method commonly used (Jay, 2003). However, the flight speed particle sampling had some technical limitations (Hermann, 2001). Moreover, the flight legal limit, altitude, prohibited airspace, flight time, and cost was another demerit. To overcome some of these restrictions, Tethered Balloon Package System (T.B.P.S.) and Recoverable Sonde System(R.S.S.) were developed with a very light optical particle counter (OPC), impactor, and condensation particle counter (CPC). Not only does it collect and measure atmospheric aerosols depending on altitudes, but it also monitors the atmospheric conditions, temperature, humidity, wind velocity, pressure, GPS data, during the measurement (Eun, 2013). In this research, atmospheric aerosol measurement using T.B.P.S. in Ansan area is performed and the measurement results will be presented. The system can also be mounted to an unmanned aerial vehicle (UAV) and create an aerial particle concentration map. Finally, we will present measurement data using Tethered Balloon Package System (T.B.P.S.) and R.S.S (Recoverable Sonde System).

  7. The Multi-sensor Airborne Radiation Survey (MARS) Instrument

    SciTech Connect

    Fast, James E.; Aalseth, Craig E.; Asner, David M.; Bonebrake, Christopher A.; Day, Anthony R.; Dorow, Kevin E.; Fuller, Erin S.; Glasgow, Brian D.; Hossbach, Todd W.; Hyronimus, Brian J.; Jensen, Jeffrey L.; Johnson, Kenneth I.; Jordan, David V.; Morgen, Gerald P.; Morris, Scott J.; Mullen, O Dennis; Myers, Allan W.; Pitts, W. Karl; Rohrer, John S.; Runkle, Robert C.; Seifert, Allen; Shergur, Jason M.; Stave, Sean C.; Tatishvili, Gocha; Thompson, Robert C.; Todd, Lindsay C.; Warren, Glen A.; Willett, Jesse A.; Wood, Lynn S.

    2013-01-11

    The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gama ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach, we found, is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. Moreover, the system is ruggedized and shock mounted for use in a variety of field applications, including airborne and maritime operations.

  8. The Multi-sensor Airborne Radiation Survey (MARS) instrument

    NASA Astrophysics Data System (ADS)

    Fast, J. E.; Aalseth, C. E.; Asner, D. M.; Bonebrake, C. A.; Day, A. R.; Dorow, K. E.; Fuller, E. S.; Glasgow, B. D.; Hossbach, T. W.; Hyronimus, B. J.; Jensen, J. L.; Johnson, K. I.; Jordan, D. V.; Morgen, G. P.; Morris, S. J.; Mullen, O. D.; Myers, A. W.; Pitts, W. K.; Rohrer, J. S.; Runkle, R. C.; Seifert, A.; Shergur, J. M.; Stave, S. C.; Tatishvili, G.; Thompson, R. C.; Todd, L. C.; Warren, G. A.; Willett, J. A.; Wood, L. S.

    2013-01-01

    The Multi-sensor Airborne Radiation Survey (MARS) project has developed a new single cryostat detector array design for high purity germanium (HPGe) gama ray spectrometers that achieves the high detection efficiency required for stand-off detection and actionable characterization of radiological threats. This approach is necessary since a high efficiency HPGe detector can only be built as an array due to limitations in growing large germanium crystals. The system is ruggedized and shock mounted for use in a variety of field applications, including airborne and maritime operations.

  9. Electrical charge measurements on fine airborne particles

    SciTech Connect

    Tardos, G.I.; Dietz, P.W.; Snaddon, R.W.L.

    1984-11-01

    A small parallel-plate precipitator and a theoretical collection model have been used to determine the distribution of charges acquired by monodisperse airborne polystyrene latex particles in a corona charger. The mean charge based on the total number of particles was found to be slightly higher than half the predicted saturation charge, and it agreed well with independent measurements made in a Faraday cage particle separator. The importance of careful measurements of particle charge in fine particle transport studies is highlighted by a discussion of the effect of charge (particle mobility) distribution width on observed transport characteristics.

  10. Airborne antenna radiation pattern code user's manual

    NASA Technical Reports Server (NTRS)

    Burnside, Walter D.; Kim, Jacob J.; Grandchamp, Brett; Rojas, Roberto G.; Law, Philip

    1985-01-01

    The use of a newly developed computer code to analyze the radiation patterns of antennas mounted on a ellipsoid and in the presence of a set of finite flat plates is described. It is shown how the code allows the user to simulate a wide variety of complex electromagnetic radiation problems using the ellipsoid/plates model. The code has the capacity of calculating radiation patterns around an arbitrary conical cut specified by the user. The organization of the code, definition of input and output data, and numerous practical examples are also presented. The analysis is based on the Uniform Geometrical Theory of Diffraction (UTD), and most of the computed patterns are compared with experimental results to show the accuracy of this solution.

  11. Lidar measurements of airborne particulate matter

    NASA Astrophysics Data System (ADS)

    Li, Guangkun; Philbrick, C. Russell

    2003-03-01

    Raman lidar techniques have been used in remote sensing to measure the aerosol optical extinction in the lower atmosphere, as well as water vapor, temperature and ozone profiles. Knowledge of aerosol optical properties assumes special importance in the wake of studies strongly correlating airborne particulate matter with adverse health effects. Optical extinction depends upon the concentration, composition, and size distribution of the particulate matter. Optical extinction from lidar returns provide information on particle size and density. The influence of relative humidity upon the growth and size of aerosols, particularly the sulfate aerosols along the northeast US region, has been investigated using a Raman lidar during several field measurement campaigns. A particle size distribution model is being developed and verified based on the experimental results. Optical extinction measurements from lidar in the NARSTO-NE-OPS program in Philadelphia PA, during summer of 1999 and 2001, have been analyzed and compared with other measurements such as PM sampling and particle size measurements.

  12. Airborne Measurements of Atmospheric Methane Using Pulsed Laser Transmitters

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Riris, Haris; Wu, Stewart; Gonzalez, Brayler; Rodriguez, Michael; Hasselbrack, William; Fahey, Molly; Yu, Anthony; Stephen, Mark; Mao, Jianping; Kawa, Stephan

    2016-01-01

    Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. At NASA Goddard Space Flight Center (GSFC) we have been developing a laser-based technology needed to remotely measure CH4 from orbit. We report on our development effort for the methane lidar, especially on our laser transmitters and recent airborne demonstration. Our lidar transmitter is based on an optical parametric process to generate near infrared laser radiation at 1651 nanometers, coincident with a CH4 absorption. In an airborne flight campaign in the fall of 2015, we tested two kinds of laser transmitters --- an optical parametric amplifier (OPA) and an optical parametric oscillator (OPO). The output wavelength of the lasers was rapidly tuned over the CH4 absorption by tuning the seed laser to sample the CH4 absorption line at several wavelengths. This approach uses the same Integrated Path Differential Absorption (IPDA) technique we have used for our CO2 lidar for ASCENDS. The two laser transmitters were successfully operated in the NASAs DC-8 aircraft, measuring methane from 3 to 13 kilometers with high precision.

  13. Airborne intercomparison of nitric oxide measurement techniques

    NASA Technical Reports Server (NTRS)

    Hoell, James M., Jr.; Gregory, Gerald L.; Mcdougal, David S.; Torres, Arnold L.; Davis, Douglas D.

    1987-01-01

    Results from an airborne intercomparison of techniques to measure tropospheric levels of nitric oxide (NO) are discussed. The intercomparison was part of the National Aeronautics and Space Administration's Global Tropospheric Experiment and was conducted during missions flown in the fall of 1983 and spring of 1984. Instruments intercompared included a laser-induced fluorescence (LIF) system and two chemiluminescence instruments (CL). NO mixing ratios from below 5 pptv (parts per trillion by volume) to greater than 100 pptv were reported, with the majority less than 20 pptv. Good correlation was observed between the measurements reported by the CL and LIF techniques. The general level of agreement observed for the ensemble of measurements obtained during the two missions provides the basis from which one can conclude that equally 'valid' measurements of background levels of NO can be expected from either CL or LIF instruments. At the same time the periods of disagreement that were observed between the CL and LIF instruments as well as between the two CL instruments highlight the difficulty of obtaining reliable measurements with NO mixing ratios in the 5-20 pptv range and emphasize the vigilance that should be maintained in future NO measurements.

  14. ARM Airborne Continuous carbon dioxide measurements

    DOE Data Explorer

    Biraud, Sebastien

    2013-03-26

    The heart of the AOS CO2 Airborne Rack Mounted Analyzer System is the AOS Manifold. The AOS Manifold is a nickel coated aluminum analyzer and gas processor designed around two identical nickel-plated gas cells, one for reference gas and one for sample gas. The sample and reference cells are uniquely designed to provide optimal flushing efficiency. These cells are situated between a black-body radiation source and a photo-diode detection system. The AOS manifold also houses flow meters, pressure sensors and control valves. The exhaust from the analyzer flows into a buffer volume which allows for precise pressure control of the analyzer. The final piece of the analyzer is the demodulator board which is used to convert the DC signal generated by the analyzer into an AC response. The resulting output from the demodulator board is an averaged count of CO2 over a specified hertz cycle reported in volts and a corresponding temperature reading. The system computer is responsible for the input of commands and therefore works to control the unit functions such as flow rate, pressure, and valve control.The remainder of the system consists of compressors, reference gases, air drier, electrical cables, and the necessary connecting plumbing to provide a dry sample air stream and reference air streams to the AOS manifold.

  15. ARM Airborne Carbon Measurements VI (ACME VI) Science Plan

    SciTech Connect

    Biraud, S

    2015-12-01

    From October 1 through September 30, 2016, the Atmospheric Radiation Measurement (ARM) Aerial Facility will deploy the Cessna 206 aircraft over the Southern Great Plains (SGP) site, collecting observations of trace-gas mixing ratios over the ARM’s SGP facility. The aircraft payload includes two Atmospheric Observing Systems, Inc., analyzers for continuous measurements of CO2 and a 12-flask sampler for analysis of carbon cycle gases (CO2, CO, CH4, N2O, 13CO2, 14CO2, carbonyl sulfide, and trace hydrocarbon species, including ethane). The aircraft payload also includes instrumentation for solar/infrared radiation measurements. This research is supported by the U.S. Department of Energy’s ARM Climate Research Facility and Terrestrial Ecosystem Science Program and builds upon previous ARM Airborne Carbon Measurements (ARM-ACME) missions. The goal of these measurements is to improve understanding of 1) the carbon exchange at the SGP site, 2) how CO2 and associated water and energy fluxes influence radiative forcing, convective processes and CO2 concentrations over the SGP site, and 3) how greenhouse gases are transported on continental scales.

  16. 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.

  17. Solar radiation measurement project

    NASA Technical Reports Server (NTRS)

    Ioup, J. W.

    1981-01-01

    The Xavier solar radiation measurement project and station are described. Measurements of the total solar radiation on a horizontal surface from an Eppley pyranometer were collected into computer data files. Total radiation in watt hours was converted from ten minute intervals to hourly intervals. Graphs of this total radiation data are included. A computer program in Fortran was written to calculate the total extraterrestrial radiation on a horizontal surface for each day of the month. Educational and social benefits of the project are cited.

  18. Wind Field Measurements With Airborne Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Menzies, Robert T.

    1999-01-01

    In collaboration with lidar atmospheric remote sensing groups at NASA Marshall Space Flight Center and National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratory, we have developed and flown the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) lidar on the NASA DC-8 research aircraft. The scientific motivations for this effort are: to obtain measurements of subgrid scale (i.e. 2-200 km) processes and features which may be used to improve parameterizations in global/regional-scale models; to improve understanding and predictive capabilities on the mesoscale; and to assess the performance of Earth-orbiting Doppler lidar for global tropospheric wind measurements. MACAWS is a scanning Doppler lidar using a pulsed transmitter and coherent detection; the use of the scanner allows 3-D wind fields to be produced from the data. The instrument can also be radiometrically calibrated and used to study aerosol, cloud, and surface scattering characteristics at the lidar wavelength in the thermal infrared. MACAWS was used to study surface winds off the California coast near Point Arena, with an example depicted in the figure below. The northerly flow here is due to the Pacific subtropical high. The coastal topography interacts with the northerly flow in the marine inversion layer, and when the flow passes a cape or point that juts into the winds, structures called "hydraulic expansion fans" are observed. These are marked by strong variation along the vertical and cross-shore directions. The plots below show three horizontal slices at different heights above sea level (ASL). Bottom plots are enlargements of the area marked by dotted boxes above. The terrain contours are in 200-m increments, with the white spots being above 600-m elevation. Additional information is contained in the original.

  19. Measurement of airborne mite allergen exposure in individual subjects.

    PubMed

    Sakaguchi, M; Inouye, S; Sasaki, R; Hashimoto, M; Kobayashi, C; Yasueda, H

    1996-05-01

    To evaluate the extent of personal exposure to airborne mite allergens, subjects were asked to carry a personal air sampler when in their houses. The level of Der 1 allergen trapped by the sampler was measured with a highly sensitive immunoassay. There were great variations in airborne Der 1 exposure in each subject. When used bedding was replaced with new allergen-free bedding, we detected a decrease in the allergen level. The use of new bedding seems to be an effective measure for reducing airborne mite allergen exposure.

  20. Earth Radiation Measurement Science

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis

    2000-01-01

    This document is the final report for NASA Grant NAG1-1959, 'Earth Radiation Measurement Science'. The purpose of this grant was to perform research in this area for the needs of the Clouds and Earth Radiant Energy System (CERES) project and for the Earth Radiation Budget Experiment (ERBE), which are bing conducted by the Radiation and Aerosols Branch of the Atmospheric Sciences Division of Langley Research Center. Earth Radiation Measurement Science investigates the processes by which measurements are converted into data products. Under this grant, research was to be conducted for five tasks: (1) Point Response Function Measurements; (2) Temporal Sampling of Outgoing Longwave Radiation; (3) Spatial Averaging of Radiation Budget Data; (4) CERES Data Validation and Applications; and (5) ScaRaB Data Validation and Application.

  1. Exploratory Meeting on Airborne Doppler Lidar Wind Velocity Measurements

    NASA Technical Reports Server (NTRS)

    Fichtel, G. H. (Editor); Kaufman, J. W. (Editor); Vaughan, W. W. (Editor)

    1980-01-01

    The scientific interests and applications of the Airborne Doppler Lidar Wind Velocity Measurement System to severe storms and local weather are discussed. The main areas include convective phenomena, local circulation, atmospheric boundary layer, atmospheric dispersion, and industrial aerodynamics.

  2. Constraining isoprene emission factors using airborne flux measurements during CABERNET

    NASA Astrophysics Data System (ADS)

    Misztal, P. K.; Karl, T.; Jiang, X.; Avise, J. C.; Scott, K.; Jonsson, H.; Guenther, A. B.; Goldstein, A. H.

    2012-12-01

    An aircraft flux study was conducted to assess biogenic volatile organic compound (BVOC) emissions from California ecosystems targeting oak woodlands and isoprene for most transects. The direct eddy covariance approach featured high speed proton transfer reaction mass spectrometry onboard a CIRPAS (Center for Interdisciplinary Remotely-Piloted Aircraft Studies) Twin Otter aircraft during June 2011 as part of the CABERNET (California Airborne BVOC Emission Research in Natural Ecosystem Transects) project. Isoprene fluxes were calculated using wavelet analysis and scaled to surface fluxes using a divergence term obtained by measuring fluxes at multiple altitudes over homogenous oak terrain. By normalization of fluxes to standard temperature and photosynthetically active radiation levels using standard BVOC modeling equations, the resulting emission factors could be directly compared with those used by MEGAN (Model of Emissions of Gases and Aerosols from Nature) and BEIGIS (Biogenic Emission Inventory Geographic Information System) models which are the most commonly used BVOC emission models for California. As expected, oak woodlands were found to be the dominant source of isoprene in all areas surrounding and in the Central Valley of California. The airborne fluxes averaged to 2 km spatial resolution matched remarkably well with current oak woodland distributions driving the models and hence the correspondence of modeled and aircraft derived emission factors was also good, although quantitative differences were encountered depending on the region and driving variables used. Fluxes measured from aircraft proved to be useful for the improvement of the accuracy of modeled predictions for isoprene and other important ozone and aerosol precursor compounds. These are the first regional isoprene flux measurements using direct eddy covariance on aircraft.

  3. Airborne Spectral Measurements of Ocean Directional Reflectance

    NASA Technical Reports Server (NTRS)

    Gatebe, Charles K.; King, Michael D.; Lyapustin, Alexei; Arnold, G. Thomas; Redemann, Jens

    2004-01-01

    During summer of 2001 NASA's Cloud Absorption Radiometer (CAR) obtained measurement of ocean angular distribution of reflected radiation or BRDF (bidirectional reflectance distribution function) aboard the University of Washington Convair CV-580 research aircraft under cloud-free conditions. The measurements took place aver the Atlantic Ocean off the eastern seaboard of the U.S. in the vicinity of the Chesapeake Light Tower and at nearby National Oceanic and Atmospheric Administration (NOAA) Buoy Stations. The measurements were in support of CLAMS, Chesapeake Lighthouse and Aircraft Measurements for Satellites, field campaign that was primarily designed to validate and improve NASA's Earth Observing System (EOS) satellite data products being derived from three sensors: MODIS (MODerate Resolution Imaging Spectro-Radiometer), MISR (Multi-angle Imaging Spectro-Radiometer) and CERES (Clouds and Earth s Radiant Energy System). Because of the high resolution of the CAR measurements and its high sensitivity to detect weak ocean signals against a noisy background, results of radiance field above the ocean are seen in unprecedented detail. The study also attempts to validate the widely used Cox-Munk model for predicting reflectance from a rough ocean surface.

  4. Thermal radiation measuring arrangement

    SciTech Connect

    Berman, H.L.; Sprout, J.C.

    1983-02-08

    In a thermal radiation measuring arrangement, a thermal radiation detector is located at the focal point of a collecting mirror, upon which incident thermal radiation from a surface, such as a building wall, is directed. The thermal radiation detector may be, for example, a thermopile, and provides an output signal having a magnitude proportional to the amount of thermal radiation which it receives. The temperature detection means detects the temperature of the thermal radiation detector and, for example, may detect the cold junction of the thermopile. In a first operating condition, a signal summing means receives the output signal from the thermal radiation detector and the temperature detection means and provides a third output signal proportional to the sum of these first and second output signals. In a second operating condition, a signal biasing means is connected into the signal summing means. The signal biasing means provides a signal to the signal summing means to cause the third output signal to become zero when radiation is received from a reference surface. When the arrangement is in the second operating condition and directed to receive thermal radiation from a second surface different from the reference surface, the signal biasing means maintains the same level of bias to the signal summing means as it did when detecting the radiation from the reference surface.

  5. Using an A-10 Aircraft for Airborne measurements of TGFs

    NASA Technical Reports Server (NTRS)

    Fishman, Gerald J.; Christian, Hugh, J.; Blakeslee, Richard J.; Grove, J. Eric; Chektman, Alexandre; Jonsson, Haflidi; Detwiler, Andrew G.

    2012-01-01

    Plans are underway to convert an A-10 combat attack aircraft into a research aircraft for thunderstorm research. This aircraft would be configured and instrumented for flights into large, convective thunderstorms. It would have the capabilities of higher altitude performance and protection for thunderstorm conditions that exceed those of aircraft now in use for this research. One area of investigation for this aircraft would be terrestrial gamma ]ray flashes (TGFs), building on the pioneering observations made by the Airborne Detector for Energetic Lightning Emissions (ADELE) project several years ago. A new and important component of the planned investigations are the continuous, detailed correlations of TGFs with the electric fields near the aircraft, as well as detailed measurements of nearby lightning discharges. Together, the x-and gamma-radiation environments, the electric field measurements, and the lightning observations (all measured on microsecond timescales) should provide new insights into this TGF production mechanism. The A -10 aircraft is currently being modified for thunderstorm research. It is anticipated that the initial test flights for this role will begin next year.

  6. Airborne Measurements of Aerosol Size Distributions During PACDEX

    NASA Astrophysics Data System (ADS)

    Rogers, D. C.; Gandrud, B.; Campos, T.; Kok, G.; Stith, J.

    2007-12-01

    The Pacific Dust Experiment (PACDEX) is an airborne project that attempts to characterize the indirect aerosol effect by tracing plumes of dust and pollution across the Pacific Ocean. This project occurred during April-May 2007 and used the NSF/NCAR HIAPER research aircraft. When a period of strong generation of dust particles and pollution was detected by ground-based and satellite sensors, then the aircraft was launched from Colorado to Alaska, Hawaii, and Japan. Its mission was to intercept and track these plumes from Asia, across the Pacific Ocean, and ultimately to the edges of North America. For more description, see the abstract by Stith and Ramanathan (this conference) and other companion papers on PACDEX. The HIAPER aircraft carried a wide variety of sensors for measuring aerosols, cloud particles, trace gases, and radiation. Sampling was made in several weather regimes, including clean "background" air, dust and pollution plumes, and regions with cloud systems. Altitude ranges extended from 100 m above the ocean to 13.4 km. This paper reports on aerosol measurements made with a new Ultra-High Sensitivity Aerosol Spectrometer (UHSAS), a Radial Differential Mobility Analyzer (RDMA), a water-based CN counter, and a Cloud Droplet Probe (CDP). These cover the size range 10 nm to 10 um diameter. In clear air, dust was detected with the UHSAS and CDP. Polluted air was identified with high concentrations of carbon monoxide, ozone, and CN. Aerosol size distributions will be presented, along with data to define the context of weather regimes.

  7. Measurements of Solar Induced Chlorophyll Fluorescence at 685 nm by Airborne Plant Fluorescence Sensor (APFS)

    NASA Astrophysics Data System (ADS)

    Morgan, F.; Yee, J. H.; Boldt, J.; Cook, W. B.; Corp, L. A.

    2015-12-01

    Solar-induced chlorophyll fluorescence (ChlF) by terrestrial vegetation is linked closely to photosynthetic efficiency that can be exploited to monitor the plant health status and to assess the terrestrial carbon budget from space. The weak, broad continuum ChlF signal can be detected from the fill-in of strong O2 absorption lines or solar Fraunhofer lines in the reflected spectral radiation. The Johns Hopkins University, Applied Physics Laboratory (JHU/APL) Airborne Plant Fluorescence Sensor (APFS) is a triple etalon Fabry-Perot interferometer designed and optimized specifically for the ChlF sensing from an airborne platform using this line fill-in technique. In this paper, we will present the results of APFS ChlF measurements obtained from a NASA Langley King Air during two airborne campaigns (12/12 in 2014 and 5/20 in 2015) over various land, river, and vegetated targets in Virginia during stressed and growth seasons.

  8. Radiative heating rates during the Airborne Arctic Stratospheric Experiment

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.; Schoeberl, Mark R.; Lait, Leslie R.; Newman, Paul A.; Proffitt, Michael H.

    1990-01-01

    A radiative transfer model and observed temperature and ozone profiles are used to compute three-dimensional fields of heating rates for the Northern Hemisphere during 1989 Airborne Arctic Stratospheric Experiment. For a clear atmosphere, an average cooling of 0.2 to 0.4 K/day is computed in the regions of the ER-2 aircraft during flight days. Tropospheric clouds will increase the cooling by 0.1 to 0.2 K/day. These cooling rates are in good agreement with the diabatic cooling estimated from N2O data, Net heating rather than cooling is computed in the area of the ozone 'minihole' which had its maximum on 1/31/89 and 2/1/89 in the vicinity of the mission. On 1/31/89 the 50 and 30 mb net heating rates are 0.1 to 0.2 K/day for clear skies, and 0.05 to 0.1 K/day for cloudy skies.

  9. Airborne water vapor DIAL research: System development and field measurements

    NASA Technical Reports Server (NTRS)

    Higdon, Noah S.; Browell, Edward V.; Ponsardin, Patrick; Chyba, Thomas H.; Grossmann, Benoist E.; Butler, Carolyn F.; Fenn, Marta A.; Mayor, Shane D.; Ismail, Syed; Grant, William B.

    1992-01-01

    This paper describes the airborne differential absorption lidar (DIAL) system developed at the NASA Langley Research Center for remote measurement of water vapor (H2O) and aerosols in the lower atmosphere. The airborne H2O DIAL system was flight tested aboard the NASA Wallops Flight Facility (WFF) Electra aircraft in three separate field deployments between 1989 and 1991. Atmospheric measurements were made under a variety of atmospheric conditions during the flight tests, and several modifications were implemented during this development period to improve system operation. A brief description of the system and major modifications will be presented, and the most significant atmospheric observations will be described.

  10. Airborne backscatter lidar measurements at three wavelengths during ELITE

    NASA Astrophysics Data System (ADS)

    Schreiber, H. G.; Wirth, Martin; Moerl, P.; Renger, Wolfgang

    1995-09-01

    The German Aerospace Establishment (DLR) operates an airborne backscatter lidar based on a Nh:YAG laser which is flashlamp-pumped at 10 Hz. It works on the wavelengths 1064, 532, and 354 nm. It is mounted downward-looking on the research aircraft Falcon 20, flying at about 12 km altitude at speeds of 200 m/s. We present airborne measurements correlated with the orbit tracks of the shuttle-borne LITE-instrument (lidar in-space technology experiment). The emphasis in data evalution is on the comparison between the airborne and the shuttle- borne lidars. First results show excellent agreement between the two instruments even on details of cirrus clouds. The results comprise cloud geometrical and optical depths, as well as profiles of aerosol backscattering coefficients at three wavelengths.

  11. Airborne measurements of gases and particles from an Alaskan wildfire

    NASA Astrophysics Data System (ADS)

    Nance, J. D.; Hobbs, Peter V.; Radke, Lawrence F.; Ward, Darold E.

    1993-08-01

    Airborne measurements of several gaseous and particulate chemical species were obtained in the emissions from a wildfire that burned in an old black spruce forest in Alaska during the summer of 1990. The relative proportions of most of the measured plume constituents are consistent with ground-based and airborne measurements in the plumes of several other biomass fires, and with laboratory measurements. Possible exceptions include the mean fine-particle emission factor, which was about 3 times larger than predicted from a regression relation based on measurements of the smoke from several prescribed biomass fires, and the mean CH4/CO molar emission ratio which was at the low end of a range of values measured for other biomass fires. Measurements of water-soluble particulate ions in the smoke plume from the Alaskan wildfire indicate that acids formed from the oxides of sulphur and nitrogen were partially neutralized inside cloud droplets by NH3 absorbed from the plume.

  12. Pulsed Airborne Lidar Measurements of C02 Column Absorption

    NASA Technical Reports Server (NTRS)

    Abshire, James B.; Riris, Haris; Allan, Graham R.; Weaver, Clark J.; Mao, Jianping; Sun, Xiaoli; Hasselbrack, William E.; Rodriquez, Michael; Browell, Edward V.

    2011-01-01

    We report on airborne lidar measurements of atmospheric CO2 column density for an approach being developed as a candidate for NASA's ASCENDS mission. It uses a pulsed dual-wavelength lidar measurement based on the integrated path differential absorption (IPDA) technique. We demonstrated the approach using the CO2 measurement from aircraft in July and August 2009 over four locations. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The 2009 measurements have been analyzed in detail and the results show approx.1 ppm random errors for 8-10 km altitudes and approx.30 sec averaging times. Airborne measurements were also made in 2010 with stronger signals and initial analysis shows approx. 0.3 ppm random errors for 80 sec averaging times for measurements at altitudes> 6 km.

  13. Airborne lidar measurements of ozone during the 1989 airborne Arctic stratospheric expedition

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Fenn, Marta A.; Kooi, Susan A.

    1991-01-01

    The NASA/NOAA Airborne Arctic Stratospheric Expedition (AASE) was conducted during the winter to study the conditions leading to possible ozone (O3) destruction in the wintertime Arctic stratosphere. As part of this experiment, the NASA-Langley airborne differential absorption lidar (DIAL) system was configured for operation on the NASA-Ames DS-8 aircraft to make measurements of O3 profiles from about 1 km above the aircraft to altitudes of 22 to 26 km. The airborne DIAL system remotely sensed O3 above the DC-8 by transmitting two laser beams at 10 Hz using wavelengths of 301.5 and 311 nm. Large scale distributions of O3 were obtained on 15 long range flights into the polar vortex during the AASE. Selected data samples are presented of O3 observed during these flights, general trends observed in O3 distributions, and correlations between these measurements and meteorological and chemical parameters. The O3 distribution observed on the first flight of the DC-8 into the polar vortex on Jan. 6 reflected the result of diabatic cooling of the air inside the vortex during the winter compared to the warmer air outside the vortex. On a potential temperature surface, the O3 mixing ratio generally increases when going from outside to inside the vortex.

  14. Advances in Quantifying the Radiative Effects of Aerosol Particles on Climate from Airborne Field Studies

    NASA Astrophysics Data System (ADS)

    Pilewskie, P.; Schmidt, K. S.; Coddington, O.; Bergstrom, R.; Redemann, J.

    2007-12-01

    In the fourth assessment report of the Intergovernmental Panel on Climate Change, large uncertainties persist in estimates of climate forcing by aerosol particles. One contributor to this uncertainty is the poorly quantified vertical distribution of solar radiation absorbed by aerosol particles, from the regional to global scale. Another is the spectral and spatial variability of surface albedo, an effect that can dominate the top-of-atmosphere perturbations due to aerosol scattering and absorption, particularly over land. Over the past three years a number of intensive airborne field experiments (ICARTT, MILAGRO, GoMACCS) have contributed significantly to our understanding of the impact of pollution outflow from urban-industrial centers on radiative forcing, using spectrally resolved radiometric measurements and novel observationally-based methods to derive forcing efficiency and flux divergence. We present an overview of some of the most significant advances in direct radiative forcing realized by these studies, and recommendations on where the greatest challenges remain. In addition we present findings from these experiments on the influence of aerosol particles on cloud radiative properties, a potentially greater effect but even more uncertain than direct radiative forcing.

  15. Bioprocess of Kosa bioaerosols: effect of ultraviolet radiation on airborne bacteria within Kosa (Asian dust).

    PubMed

    Kobayashi, Fumihisa; Maki, Teruya; Kakikawa, Makiko; Yamada, Maromu; Puspitasari, Findya; Iwasaka, Yasunobu

    2015-05-01

    Kosa (Asian dust) is a well-known weather phenomenon in which aerosols are carried by the westerly winds from inland China to East Asia. Recently, the frequency of this phenomenon and the extent of damage caused have been increasing. The airborne bacteria within Kosa are called Kosa bioaerosols. Kosa bioaerosols have affected ecosystems, human health and agricultural productivity in downwind areas. In order to develop a new and useful bacterial source and to identify the source region of Kosa bioaerosols, sampling, isolation, identification, measurement of ultraviolet (UV) radiation tolerance and experimental simulation of UV radiation conditions were performed during Kosa bioaerosol transportation. We sampled these bioaerosols using a Cessna 404 airplane and a bioaerosol sampler at an altitude of approximately 2900 m over the Noto Peninsula on March 27, 2010. The bioaerosol particles were isolated and identified as Bacillus sp. BASZHR 1001. The results of the UV irradiation experiment showed that the UV radiation tolerance of Kosa bioaerosol bacteria was very high compared with that of a soil bacterium. Moreover, the UV radiation tolerance of Kosa bioaerosol spores was higher than that of soil bacterial spores. This suggested that Kosa bioaerosols are transported across the atmosphere as living spores. Similarly, by the experimental simulation of UV radiation conditions, the limited source region of this Kosa bioaerosol was found to be southern Russia and there was a possibility of transport from the Kosa source area.

  16. Airborne High Spectral Resolution Lidar Measurements of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Ferrare, R.; Hostetler, C.; Hair, J.; Cook, A.; Harper, D.; Kleinman, L.; Clarke, A.; Russell, P.; Redemann, J.; Livingston, J.; Szykman, J.; Al-Saadi, J.

    2007-05-01

    NASA Langley Research Center (LaRC) recently developed an airborne High Spectral Resolution Lidar (HSRL) to measure aerosol distributions and optical properties. The HSRL technique takes advantage of the spectral distribution of the lidar return signal to discriminate aerosol and molecular signals and thereby measure aerosol extinction and backscatter independently. The LaRC instrument employs the HSRL technique to measure aerosol backscatter and extinction profiles at 532 nm and the standard backscatter lidar technique to measure aerosol backscatter profiles at 1064 nm. Depolarization profiles are measured at both wavelengths. Since March 2006, the airborne HSRL has acquired over 215 flight hours of data deployed on the NASA King Air B200 aircraft during several field experiments. Most of the flights were conducted during two major field experiments. The first major experiment was the joint Megacity Initiative: Local and Global Research Observations (MILAGRO) /Megacity Aerosol Experiment in Mexico City (MAX-MEX)/Intercontinental Chemical Transport Experiment-B (INTEX B) experiment that was conducted during March 2006 to investigate the evolution and transport of pollution from Mexico City. The second major experiment was the Texas Air Quality Study (TEXAQS)/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) that was conducted during August and September 2006 to investigate climate and air quality in the Houston/Gulf of Mexico region. Several flights were also conducted to help validate the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) lidar on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite (CALIPSO) satellite. In February 2007, several flights were carried out as part of an Environmental Protection Agency (EPA) experiment to assess air quality in central California. Airborne HSRL data acquired during these missions were used to quantify aerosol extinction and optical thickness contributed by various aerosol types

  17. Ground and Airborne Methane Measurements with an Optical Parametric Amplifier

    NASA Technical Reports Server (NTRS)

    Numata, Kenji

    2012-01-01

    We report on ground and airborne atmospheric methane measurements with a differential absorption lidar using an optical parametric amplifier (OPA). Methane is a strong greenhouse gas on Earth and its accurate global mapping is urgently needed to understand climate change. We are developing a nanosecond-pulsed OPA for remote measurements of methane from an Earth-orbiting satellite. We have successfully demonstrated the detection of methane on the ground and from an airplane at approximately 11-km altitude.

  18. Radiative effects of polar stratospheric clouds during the Airborne Antarctic Ozone Experiment and the Airborne Arctic Stratospheric Expedition

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.

    1992-01-01

    Results are presented of a study of the radiative effects of polar stratospheric clouds during the Airborne Antarctic Ozone Experiment (AAOE) and the Airborne Arctic Stratospheric Expedition (AASE) in which daily 3D Type I nitric acid trihydrate (NAT) and Type II water ice polar stratospheric clouds (PSCs) were generated in the polar regions during AAOE and the AASE aircraft missions. Mission data on particular composition and size, together with NMC-analyzed temperatures, are used. For AAOE, both Type I and Type II clouds were formed for the time period August 23 to September 17, after which only Type I clouds formed. During AASE, while Type I clouds were formed for each day between January 3 and February 10, Type II clouds formed on only two days, January 24 and 31. Mie theory and a radiative transfer model are used to compute the radiative heating rates during the mission periods, for clear and cloudy lower sky cases. Only the Type II water ice clouds have a significant radiative effect, with the Type I NATO PSCs generating a net heating or cooling of 0.1 K/d or less.

  19. The Airborne Measurements of Methane Fluxes (AIRMETH) Arctic Campaign (Invited)

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    One of the most pressing questions with regard to climate feedback processes in a warming Arctic is the regional-scale methane release from Arctic permafrost areas. The Airborne Measurements of Methane Fluxes (AIRMETH) campaign is designed to quantitatively and spatially explicitly address this question. Ground-based eddy covariance (EC) measurements provide continuous in-situ observations of the surface-atmosphere exchange of methane. However, these observations are rare in the Arctic permafrost zone and site selection is bound by logistical constraints among others. Consequently, these observations cover only small areas that are not necessarily representative of the region of interest. Airborne measurements can overcome this limitation by covering distances of hundreds of kilometers over time periods of a few hours. Here, we present the potential of environmental response functions (ERFs) for quantitatively linking methane flux observations in the atmospheric surface layer to meteorological and biophysical drivers in the flux footprints. For this purpose thousands of kilometers of AIRMETH data across the Alaskan North Slope are utilized, with the aim to extrapolate the airborne EC methane flux observations to the entire North Slope. The data were collected aboard the research aircraft POLAR 5, using its turbulence nose boom and fast response methane and meteorological sensors. After thorough data pre-processing, Reynolds averaging is used to derive spatially integrated fluxes. To increase spatial resolution and to derive ERFs, we then use wavelet transforms of the original high-frequency data. This enables much improved spatial discretization of the flux observations, and 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 the methane flux observations and the meteorological and

  20. Airborne Lidar Measurements of Atmospheric Pressure Made Using the Oxygen A-Band

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Rodriquez, Michael; Allan, Graham R.; Hasselbrack, William E.; Stephen, Mark A.; Abshire, James B.

    2011-01-01

    We report on airborne measurements of atmospheric pressure using a fiber-laser based lidar operating in the oxygen A-band near 765 nm and the integrated path differential absorption measurement technique. Our lidar uses fiber optic technology and non-linear optics to generate tunable laser radiation at 765 nm, which overlaps an absorption line pair in the Oxygen A-band. We use a pulsed time resolved technique, which rapidly steps the laser wavelength across the absorption line pair, a 20 cm telescope and photon counting detector to measure Oxygen concentrations.

  1. A Study of Reflected Sonic Booms Using Airborne Measurements

    NASA Technical Reports Server (NTRS)

    Kantor, Samuel R.; Cliatt, Larry J., II

    2017-01-01

    In support of ongoing efforts to bring commercial supersonic flight to the public, the Sonic Booms in Atmospheric Turbulence (SonicBAT) flight test was conducted at NASA Armstrong Flight Research Center. During this test, airborne sonic boom measurements were made using an instrumented TG-14 motor glider, called the Airborne Acoustic Measurement Platform (AAMP).During the flight program, the AAMP was consistently able to measure the sonic boom wave that was reflected off of the ground, in addition to the incident wave, resulting in the creation of a completely unique data set of airborne sonic boom reflection measurements. This paper focuses on using this unique data set to investigate the ability of sonic boom modeling software to calculate sonic boom reflections. Because the algorithms used to model sonic boom reflections are also used to model the secondary carpet and over the top booms, the use of actual flight data is vital to improving the understanding of the effects of sonic booms outside of the primary carpet. Understanding these effects becomes especially important as the return of commercial supersonic approaches, as well as ensuring the accuracy of mission planning for future experiments.

  2. Active-passive airborne ocean color measurement. II - Applications

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.; Yungel, J. K.

    1986-01-01

    Reported here for the first time is the use of a single airborne instrument to make concurrent measurements of oceanic chlorophyll concentration by (1) laser-induced fluorescence, (2) passive upwelling radiance, and (3) solar-induced chlorophyll fluorescence. Results from field experiments conducted with the NASA airborne oceanographic lidar (AOL) in the New York Bight demonstrate the capability of a single active-passive instrument to perform new and potentially important ocean color studies related to (1) active lidar validation of passive ocean color in-water algorithms, (2) chlorophyll a in vivo fluorescence yield variability, (3) calibration of active multichannel lidar systems, (4) effect of sea state on passive and active ocean color measurements, (5) laser/solar-induced chlorophyll fluorescence investigations, and (6) subsequent improvement of satellite-borne ocean color scanners. For validation and comparison purposes a separate passive ocean color sensor was also flown along with the new active-passive sensor during these initial field trials.

  3. Radon measurements aboard the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Kritz, Mark A.; Rosner, Stefan W.

    1995-01-01

    We have carried out three (piggyback) radon-related projects aboard the KAO. The first, which was limited to upper tropospheric measurements while in level flight, revealed the systematic occurrence of unexpectedly high radon concentrations in this region of the atmosphere. The second project was an instrument development project, which led to the installation of an automatic radon measurement system aboard the NASA ER-2 High Altitude Research Aircraft. In the third, we installed a new system capable of collecting samples during the normal climb and descent of the KAO. The results obtained in these projects have resulted in significant contributions to our knowledge of atmospheric transport processes, and are currently playing a key role in the validation of global circulation and transport models.

  4. Airborne Measurements of atmospheric PAH's across Europe

    NASA Astrophysics Data System (ADS)

    Davison, B.; Jaward, F.; Jones, K.; Lee, R.

    2003-04-01

    Atmospheric measurements of PAHs were taken aboard the DRL Falcon 20 during May 2001. A sampling system was designed to work aboard this aircraft platform. Particulate PAHs were collected on a glass fiber filter (GFF) with their gaseous component concentrated on a polyurethane foam sheets located behind the filter. Typically sampling volumes of between 20-50m^3 were collected which equated to a collection time of about 30minutes. In this way the distance travelled was kept within an acceptable level, about 60 nautical miles. The average concentrations of the data set for phenanthrene was 450 pg m-3 while values for many of the heavier PAH marker compounds used in the UK such as benzo(a)pyrene, diben(ah)anthracene were below the detection limits on all flights. The results will be discussed with consideration of location, altitude and airmass trajectory.

  5. Airborne sodium lidar measurements of gravity wave intrinsic parameters

    NASA Astrophysics Data System (ADS)

    Kwon, Kang H.; Gardner, Chester S.

    1990-11-01

    A data analysis technique for determining gravity wave intrinsic parameters including wave propagation direction is described. The technique involves measuring the altitude variations of the wave-induced density perturbations of the atmospheric Na layer. This technique can be used with airborne lidars, multiple ground-based lidars, and steerable lidars. In this paper the technique is applied to airborne Na lidar data obtained during a round-trip flight from Denver, Colorado, to the Pacific Coast in November 1986. During the flight, strong wave perturbations were observed in the Na layer near the Pacific coast over a horizontal distance of nearly 700 km. The intrinsic horizontal wavelength of this wave was estimated to be about 85 km, and the vertical wavelength was 4.1 km. The intrinsic period was about 102 min, and the propagation direction was almost due south.

  6. Airborne UV DIAL Measurements of Ozone and Aerosols

    NASA Technical Reports Server (NTRS)

    Grant, William B.; Browell, Edward V.

    2000-01-01

    The NASA Langley Research Center's airborne UV Differential Absorption Lidar (DIAL) system measures vertical profiles of ozone and aerosols above and below the aircraft along its flight track. This system has been used in over 20 airborne field missions designed to study the troposphere and stratosphere since 1980. Four of these missions involved tropospheric measurement programs in the Pacific Ocean with two in the western North Pacific and two in the South Pacific. The UV DIAL system has been used in these missions to study such things as pollution outflow, long-range transport, and stratospheric intrusions; categorize the air masses encountered; and to guide the aircraft to altitudes where interesting features can be studied using the in situ instruments. This paper will highlight the findings with the UV DIAL system in the Pacific Ocean field programs and introduce the mission planned for the western North Pacific for February-April 2001. This will be an excellent opportunity for collaboration between the NASA airborne mission and those with ground-based War systems in Asia Pacific Rim countries to make a more complete determination of the transport of air from Asia to the western Pacific.

  7. Analyzers Measure Greenhouse Gases, Airborne Pollutants

    NASA Technical Reports Server (NTRS)

    2012-01-01

    In complete darkness, a NASA observatory waits. When an eruption of boiling water billows from a nearby crack in the ground, the observatory s sensors seek particles in the fluid, measure shifts in carbon isotopes, and analyze samples for biological signatures. NASA has landed the observatory in this remote location, far removed from air and sunlight, to find life unlike any that scientists have ever seen. It might sound like a scene from a distant planet, but this NASA mission is actually exploring an ocean floor right here on Earth. NASA established a formal exobiology program in 1960, which expanded into the present-day Astrobiology Program. The program, which celebrated its 50th anniversary in 2010, not only explores the possibility of life elsewhere in the universe, but also examines how life begins and evolves, and what the future may hold for life on Earth and other planets. Answers to these questions may be found not only by launching rockets skyward, but by sending probes in the opposite direction. Research here on Earth can revise prevailing concepts of life and biochemistry and point to the possibilities for life on other planets, as was demonstrated in December 2010, when NASA researchers discovered microbes in Mono Lake in California that subsist and reproduce using arsenic, a toxic chemical. The Mono Lake discovery may be the first of many that could reveal possible models for extraterrestrial life. One primary area of interest for NASA astrobiologists lies with the hydrothermal vents on the ocean floor. These vents expel jets of water heated and enriched with chemicals from off-gassing magma below the Earth s crust. Also potentially within the vents: microbes that, like the Mono Lake microorganisms, defy the common characteristics of life on Earth. Basically all organisms on our planet generate energy through the Krebs Cycle, explains Mike Flynn, research scientist at NASA s Ames Research Center. This metabolic process breaks down sugars for energy

  8. Radon emanation and soil moisture effects on airborne gamma-ray measurements

    SciTech Connect

    Grasty, R.L.

    1997-09-01

    A theoretical model is developed to explain variations in airborne gamma-ray measurements over a calibration range near Ottawa, Ontario. The gamma-ray flux from potassium and the thorium decay series showed an expected decrease with increasing soil moisture. However, the gamma-ray flux from the uranium decay series was highest in the spring when the ground was water-saturated and even covered with snow. These results are explained through the build-up of radon and its associated gamma-ray-emitting decay products in the clay soil of the calibration range with increasing soil moisture. Similar results were found from airborne measurements over other clay soils. However, measurements over sandy soils showed that the count rates from all three radio elements increased with decreasing soil moisture. This difference between soil types was attributed to the lower radon emanation of the more coarse-grained sandy soils compared to finer-grained clay soils. The theoretical and experimental results demonstrate that any estimate of the natural gamma-ray field caused by radium in the ground must take into consideration the radon emanation coefficient of the soil. The radon diffusion coefficient of the soil must also be considered since it depends strongly on soil moisture. This has significant implications for the assessment of outdoor radiation doses using laboratory analyses of soil samples and the use of ground and airborne gamma-ray measurements for radon potential mapping.

  9. Airborne laser scanning for forest health status assessment and radiative transfer modelling

    NASA Astrophysics Data System (ADS)

    Novotny, Jan; Zemek, Frantisek; Pikl, Miroslav; Janoutova, Ruzena

    2013-04-01

    Structural parameters of forest stands/ecosystems are an important complementary source of information to spectral signatures obtained from airborne imaging spectroscopy when quantitative assessment of forest stands are in the focus, such as estimation of forest biomass, biochemical properties (e.g. chlorophyll /water content), etc. The parameterization of radiative transfer (RT) models used in latter case requires three-dimensional spatial distribution of green foliage and woody biomass. Airborne LiDAR data acquired over forest sites bears these kinds of 3D information. The main objective of the study was to compare the results from several approaches to interpolation of digital elevation model (DEM) and digital surface model (DSM). We worked with airborne LiDAR data with different density (TopEye Mk II 1,064nm instrument, 1-5 points/m2) acquired over the Norway spruce forests situated in the Beskydy Mountains, the Czech Republic. Three different interpolation algorithms with increasing complexity were tested: i/Nearest neighbour approach implemented in the BCAL software package (Idaho Univ.); ii/Averaging and linear interpolation techniques used in the OPALS software (Vienna Univ. of Technology); iii/Active contour technique implemented in the TreeVis software (Univ. of Freiburg). We defined two spatial resolutions for the resulting coupled raster DEMs and DSMs outputs: 0.4 m and 1 m, calculated by each algorithm. The grids correspond to the same spatial resolutions of hyperspectral imagery data for which the DEMs were used in a/geometrical correction and b/building a complex tree models for radiative transfer modelling. We applied two types of analyses when comparing between results from the different interpolations/raster resolution: 1/calculated DEM or DSM between themselves; 2/comparison with field data: DEM with measurements from referential GPS, DSM - field tree alometric measurements, where tree height was calculated as DSM-DEM. The results of the analyses

  10. Airborne measurements of spatial NO2 distributions during AROMAT

    NASA Astrophysics Data System (ADS)

    Meier, Andreas Carlos; Seyler, André; Schönhardt, Anja; Richter, Andreas; Ruhtz, Thomas; Lindemann, Carsten; Burrows, John P.

    2015-04-01

    Nitrogen oxides, NOx (NOx = NO + NO2) play a key role in tropospheric chemistry. In addition to their directly harmful effects on the respiratory system of living organisms, they influence the levels of tropospheric ozone and contribute to acid rain and eutrophication of ecosystems. As they are produced in combustion processes, they can serve as an indicator for anthropogenic air pollution. In September 2014 several European research groups conducted the ESA funded Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign to test and intercompare newly developed airborne observation sytsems dedicated to air quality satellite validation studies. The IUP Bremen contributed to this campaign with its Airborne imaging DOAS instrument for Measurements of Atmospheric Pollution (AirMAP) on board a Cessna 207 turbo, operated by the FU Berlin. AirMAP allows the retrieval of integrated NO2 column densities in a stripe below the aircraft at a fine spatial resolution of up to 30 x 80 m2, at a typical flight altitude. Measurements have been performed over the city of Bucharest, creating for the first time high spatial resolution maps of Bucharest's NO2 distribution in a time window of approx. 2 hours. The observations were synchronised with ground-based car MAX-DOAS measurements for comparison. In addition, measurements were taken over the city of Berlin, Germany and at the Rovinari power plant, Romania. In this work the results of the research flights will be presented and conclusions will be drawn on the quality of the measurements, their applicability for satellite data validation and possible improvements for future measurements.

  11. Measurement of airborne {sup 218}Po - A Bayesian approach

    SciTech Connect

    Groer, P.G.; Lo, Y.

    1996-12-01

    The standard mathematical treatment of the buildup and decay of airborne radionuclides on a filter paper uses the solutions of the so-called bateman equations adapted to the sampling process. The equations can be interpreted as differential equations for the expectation of an underlying stochastic process, which describes the random fluctuations in the accumulation and decay of the sampled radioactive atoms. The process for the buildup and decay of airborne {sup 218}Po can be characterized as an {open_quotes}immigration-death process{close_quotes} in the widely adopted, biologically based jargon. The probability distribution for the number of {sup 218}Po atoms, accumulated after sampling time t, is Poisson. We show that the distribution of the number of counts, registered by a detector with efficiency {epsilon} during a counting period T after the end of sampling, it also Poisson, with mean dependent on {epsilon},t,T, the flowrate and N{sub o}, the number of airborne {sup 218}Po atoms per unit volume. This Poisson distribution was used to construct the likelihood given the observed number of counts. After inversion with Bayes` Theorem we obtained the posterior density for N{sub o}. This density characterizes the remaining uncertainty about the measured under of {sup 218}Po atoms per unit volume of air. 6 refs., 3 figs., 1 tab.

  12. Functional requirements document for measuring emissions of airborne radioactive materials

    SciTech Connect

    Criddle, J.D. Jr.

    1994-09-01

    This document states the functional requirements and procedures for systems making measurements of radioactive airborne emissions from facilities at the Hanford Site. The following issues are addressed in this document: Definition of the program objectives; Selection of the overall approach to collecting the samples; Sampling equipment design; Sampling equipment maintenance, and quality assurance issues. The intent of this document is to assist WHC in demonstrating a high quality of air emission measurements with verified system performance based on documented system design, testing, inspection, and maintenance.

  13. Recent modifications, enhancements, and measurements with an airborne lidar system

    NASA Astrophysics Data System (ADS)

    DeCoursey, Robert J.; Osborn, Mary T.; Winker, David M.; Woods, David C.

    1996-06-01

    The NASA Langley Research Center's 14-inch airborne aerosol lidar system, which is routinely flown on several NASA aircraft including the DC-8 and the P-3, has been upgraded with several modifications to enhance its measurement capabilities. A new 900 mJ, 10 pps Nd:YAG laser was added with the capability of producing 5 watts of power at 1064 nm, 2.5 watts at 532 nm and 1.5 watts at 355 nm. The existing detector package has been modified to accommodate the three wavelengths and to permit cross-polarization measurements at 532 nm. New software was developed for on- line data visualization and analysis, and computer- controlled laser alignment is being incorporated. The system is now capable of producing real-time color modulated backscatter plots. Other additions include a Pentium/90 processor, GPS (Global Positioning System) and ARINC (Aeronautical Radio Inc.) receivers for acquiring accurate aircraft position data. In 1992 and 1993 this system was flown on several airborne missions to map and characterize the stratospheric aerosol cloud produced by the 1991 eruption of the Mount Pinatubo volcano. Efforts to map the global distribution of Pinatubo were made on both daytime as well as nighttime flights from Moffett Field in California to the South Pacific, to Central and South America, to Australia and to Alaska. In September 1994, the system (aboard NASA's P-3) made correlative measurements along shuttle orbit ground tracks in support of the Lidar In-space Technology Experiment flown on the Space Shuttle. In this paper the system upgrades will be discussed and selected data obtained during these recent airborne campaigns will be presented.

  14. A towed airborne platform for turbulence measurements over the ocean

    NASA Astrophysics Data System (ADS)

    Friehe, Carl; Khelif, Djamal

    2008-11-01

    Measurements of wind stress and associated heat and mass fluxes (water vapor and CO2) down to ˜10 meters height over the ocean are required to establish parameterizations for wave, weather, hurricane and climate models. At high winds and accompanying sea states, such measurements are difficult or impossible. A new airborne instrumented towed platform has been developed that allows measurements down to 10 meters under radar-altitude control while the tow aircraft is safely above. Measurements include the three components of the wind, temperature, humidity, infrared surface temperature, CO2, and motion and navigational parameters. The bandwidth of the sensors allows calculation of the Reynolds averaged covariance's of stress and sensible heat and evaporation fluxes. Results are compared to equivalent measurements made with an instrumented aircraft. We would like to thank Robert Bluth of the Naval Postgraduate School and Jesse Barge and Dan Bierly of Zivko Aeronautics.

  15. Science Measurement Requirements for Imaging Spectrometers from Airborne to Spaceborne

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Asner, Gregory P.; Boardman, Joseph; Ungar, Stephen; Mouroulis, Pantazis

    2006-01-01

    This slide presentation reviews the objectives of the work to create imaging spectrometers. The science objectives are to remotely determine the properties of the surface and atmosphere (physics, chemistry and biology) revealed by the interaction of electromagnetic energy with matter via spectroscopy. It presents a review the understanding of spectral, radiometric and spatial science measurement requirements for imaging spectrometers based upon science research results from past and current airborne and spaceborne instruments. It also examines the future requirements that will enable the next level of imaging spectroscopy science.

  16. Real-Time Airborne Gamma-Ray Background Estimation Using NASVD with MLE and Radiation Transport for Calibration

    SciTech Connect

    Kulisek, Jonathan A.; Schweppe, John E.; Stave, Sean C.; Bernacki, Bruce E.; Jordan, David V.; Stewart, Trevor N.; Seifert, Carolyn E.; Kernan, Warnick J.

    2015-06-01

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements. This method is built upon on the noise-adjusted singular value decomposition (NASVD) technique that was previously developed for estimating the potassium (K), uranium (U), and thorium (T) concentrations in soil post-flight. The method can be calibrated using K, U, and T spectra determined from radiation transport simulations along with basis functions, which may be determined empirically by applying maximum likelihood estimation (MLE) to previously measured airborne gamma-ray spectra. The method was applied to both measured and simulated airborne gamma-ray spectra, with and without man-made radiological source injections. Compared to schemes based on simple averaging, this technique was less sensitive to background contamination from the injected man-made sources and may be particularly useful when the gamma-ray background frequently changes during the course of the flight.

  17. 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

  18. Aerosol Classification using Airborne High Spectral Resolution Lidar Measurements

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 aircraft has acquired extensive datasets of aerosol extinction (532 nm), aerosol optical thickness (AOT) (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) profiles during 18 field missions that have been conducted over North America since 2006. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, backscatter color ratio, spectral depolarization ratio) are shown to vary with location and aerosol type. A methodology based on observations of known aerosol types is used to qualitatively classify the extensive set of HSRL aerosol measurements into eight separate types. Several examples are presented showing how the aerosol intensive parameters vary with aerosol type and how these aerosols are classified according to this new methodology. The HSRL-based classification reveals vertical variability of aerosol types during the NASA ARCTAS field experiment conducted over Alaska and northwest Canada during 2008. In two examples derived from flights conducted during ARCTAS, the HSRL classification of biomass burning smoke is shown to be consistent with aerosol types derived from coincident airborne in situ measurements of particle size and composition. The HSRL retrievals of aerosol optical thickness and inferences of aerosol types are used to apportion aerosol optical thickness to aerosol type; results of this analysis are shown for several experiments.

  19. Radiative Interactions of Clouds Embedded in wildfire Smoke using Multiangular Airborne observations

    NASA Astrophysics Data System (ADS)

    Gautam, R.; Gatebe, C. K.; Singh, M.; Varnai, T.; Poudyal, R.

    2015-12-01

    Presence of absorbing aerosols above clouds causes its apparent darkening, observed at Top of Atmosphere. Owing to the large radiative warming and potential impacts on climate, above clouds aerosols (ACA) have recently been characterized in multiple satellite-based studies. While satellite data have particularly been useful in demonstrating the climate impact of ACA, uncertainties remain in the indepth understanding of aerosol-cloud radiative interactions. Recent studies also indicate large uncertainties in satellite retrievals of ACA optical depth and Single Scattering Albedo (SSA), which are among the most important parameters in their radiative impact. Here, we present observations of clouds embedded in vertically extended and optically thick smoke, from NASA/GSFC's airborne Cloud Absorption Radiometer. We focus on smoke plumes associated with pyroconvective activity from wildfires in Canada, during the ARCTAS campaign. Our key findings include characterization of clouds embedded in smoke, associated with a strong positive reflectance (R) gradient in the UV-VIS-NIR spectrum, as opposed to an (expected) negative gradient for cloud-free smoke and a flat spectrum for smoke-free cloud cover. Several cases of clouds embedded in thick smoke were found, when the aircraft made circular/spiral measurements, which not only allowed the complete characterization of angular distribution of smoke scattering, but also provided vertical distribution of smoke and clouds (within 0.5-5km). Specifically, the largest cloud darkening was found in the UV/VIS, with significant reduction at R0.34μm in contrast to the NIR wavelengths (e.g. 1.27μm). The observed darkening was found to be associated with large optical depths (0.5 - 3) and moderately low SSA (0.85-0.93 at 530nm), resulting in significantly large forcing efficiency of 250Wm-2τ-1 (using coincident sunphotometer, insitu and irradiance measurements). Our observations of smoke-cloud radiative interactions were found to be

  20. Airborne Particle Size Distribution Measurements at USDOE Fernald

    SciTech Connect

    Harley, N.H.; Chittaporn, P.; Heikkinen, M.; Medora, R.; Merrill, R.

    2003-03-27

    There are no long term measurements of the particle size distribution and concentration of airborne radionuclides at any USDOE facility except Fernald. Yet the determinant of lung dose is the particle size, determining the airway and lower lung deposition. Beginning in 2000, continuous (6 to 8 weeks) measurements of the aerosol particle size distribution have been made with a miniature sampler developed under EMSP. Radon gas decays to a chain of four short lived solid radionuclides that attach immediately to the resident atmospheric aerosol. These in turn decay to long lived polonium 210. Alpha emitting polonium is a tracer for any atmospheric aerosol. Six samplers at Fernald and four at QC sites in New Jersey show a difference in both polonium concentration and size distribution with the winter measurements being higher/larger than summer by almost a factor of two at all locations. EMSP USDOE Contract DE FG07 97ER62522.

  1. Method for measuring the size distribution of airborne rhinovirus

    SciTech Connect

    Russell, M.L.; Goth-Goldstein, R.; Apte, M.G.; Fisk, W.J.

    2002-01-01

    About 50% of viral-induced respiratory illnesses are caused by the human rhinovirus (HRV). Measurements of the concentrations and sizes of bioaerosols are critical for research on building characteristics, aerosol transport, and mitigation measures. We developed a quantitative reverse transcription-coupled polymerase chain reaction (RT-PCR) assay for HRV and verified that this assay detects HRV in nasal lavage samples. A quantitation standard was used to determine a detection limit of 5 fg of HRV RNA with a linear range over 1000-fold. To measure the size distribution of HRV aerosols, volunteers with a head cold spent two hours in a ventilated research chamber. Airborne particles from the chamber were collected using an Andersen Six-Stage Cascade Impactor. Each stage of the impactor was analyzed by quantitative RT-PCR for HRV. For the first two volunteers with confirmed HRV infection, but with mild symptoms, we were unable to detect HRV on any stage of the impactor.

  2. Ground and Airborne Methane Measurements Using Optical Parametric Amplifiers

    NASA Technical Reports Server (NTRS)

    Numata, Kenji; Riris, Haris; Li, Steve; Wu, Stewart; Kawa, Stephan R.; Abshire, James Brice; Dawsey, Martha; Ramanathan, Anand

    2011-01-01

    We report on ground and airborne methane measurements with an active sensing instrument using widely tunable, seeded optical parametric generation (OPG). The technique has been used to measure methane, CO2, water vapor, and other trace gases in the near and mid-infrared spectral regions. Methane is a strong greenhouse gas on Earth and it is also a potential biogenic marker on Mars and other planetary bodies. Methane in the Earth's atmosphere survives for a shorter time than CO2 but its impact on climate change can be larger than CO2. Carbon and methane emissions from land are expected to increase as permafrost melts exposing millennial-age carbon stocks to respiration (aerobic-CO2 and anaerobic-CH4) and fires. Methane emissions from c1athrates in the Arctic Ocean and on land are also likely to respond to climate warming. However, there is considerable uncertainty in present Arctic flux levels, as well as how fluxes will change with the changing environment. For Mars, methane measurements are of great interest because of its potential as a strong biogenic marker. A remote sensing instrument that can measure day and night over all seasons and latitudes can localize sources of biogenic gas plumes produced by subsurface chemistry or biology, and aid in the search for extra-terrestrial life. In this paper we report on remote sensing measurements of methane using a high peak power, widely tunable optical parametric generator (OPG) operating at 3.3 micrometers and 1.65 micrometers. We have demonstrated detection of methane at 3.3 micrometers and 1650 nanometers in an open path and compared them to accepted standards. We also report on preliminary airborne demonstration of methane measurements at 1.65 micrometers.

  3. Lung cancer in relation to airborne radiation levels

    SciTech Connect

    Helsing, K.J.; Natta, P.V.; Comstock, G.W. ); Kalin, Heidi ) Chee, E. )

    1992-01-01

    A 1986 aeroradiometric survey of the eastern two-thirds of Washington County, Maryland provided and opportunity to study lung cancers in relation to gamma radiation levels. In the first approach, lung cancer deaths between 1963 and 1975 in four areas of the county categorized as low, moderately low, moderately high, and high showed relative risks of 1.00, 0.93, 1.01, and 1.43, respectively, after adjustment of sex, age, and smoking. A second approach used lung cancer cases diagnosed between 1975 and 1989, controls matched to cases by race, sex, and age, and aerometric radiation readings above the individual residences. In four levels of increasing gamma radiation, odds ratios adjusted for smoking were 1.00, 0.84, 0.90, and 0.92, respectively. No differences were statistically significant.

  4. Processing and analysis of radiometer measurements for airborne reconnaissance

    NASA Astrophysics Data System (ADS)

    Suess, Helmut

    1990-11-01

    Thi8 paper describes selected results of airborne, radiometric imaging measurements at 90 GHz and 140 GHz relevant for the application in reconnaissance. Using a temperature resolution below 0.5 K and an angular resolution of about 1 degree high quality images show the capability of discriminating between many brightness temperature classes within our natural environment and man-made objects. Measurement examples are given for cloud and fog penetration at 90 GHz, for the detection of vehicles on roads, and for the detection and classification of airports and airplanes. The application of different contour enhancement methods (Marr-Hildreth and Canny) shows the possibility of extracting lines and shapes precisely in order to improve automatic target recognition. The registration of the passive images with corresponding X-band synthetic aperture images from the same area is carried out and the high degree of correlation is dicussed.

  5. Processing and analysis of radiometer measurements for airborne reconnaissance

    NASA Technical Reports Server (NTRS)

    Suess, Helmut

    1990-01-01

    This paper describes selected results of airborne, radiometric imaging measurements at 90 GHz and 140 GHz relevant for the application in reconnaissance. Using a temperature resolution below 0.5 K and an angular resolution of about 1-degree high-quality images show the capability of discriminating between many brightness temperature classes within our natural environment and man-made objects. Measurement examples are given for cloud and fog penetration at 90 GHz, for the detection of vehicles on roads, and for the detection and classification of airports and airplanes. The application of different contour enhancement methods (Marr-Hildreth and Canny) shows the possibility of extracting lines and shapes precisely in order to improve automatic target recognition. The registration of the passive images with corresponding X-band synthetic aperture images from the same area is carried out and the high degree of correlation is discussed.

  6. Airborne compact rotational Raman lidar for temperature measurement.

    PubMed

    Wu, Decheng; Wang, Zhien; Wechsler, Perry; Mahon, Nick; Deng, Min; Glover, Brent; Burkhart, Matthew; Kuestner, William; Heesen, Ben

    2016-09-05

    We developed an airborne compact rotational Raman lidar (CRL) for use on the University of Wyoming King Air (UWKA) aircraft to obtain two-dimensional (2D) temperature disman tributions. It obtained fine-scale 2D temperature distributions within 3 km below the aircraft for the first time during the PECAN (Plains Elevated Convection At Night) campaign in 2015. The CRL provided nighttime temperature measurements with a random error of <0.5 K within 800 m below aircraft at 45 m vertical and 1000 m horizontal resolution. The temperatures obtained by the CRL and a radiosonde agreed. Along with water vapor and aerosol measurements, the CRL provides critical parameters on the state of the lower atmosphere for a wide range of atmospheric research.

  7. Application of Bayesian decision theory to airborne gamma snow measurement

    NASA Technical Reports Server (NTRS)

    Bissell, V. C.

    1975-01-01

    Measured values of several variables are incorporated into the calculation of snow water equivalent as measured from an aircraft by snow attenuation of terrestrial gamma radiation. Bayesian decision theory provides a snow water equivalent measurement by taking into account the uncertainties in the individual measurement variables and filtering information about the measurement variables through prior notions of what the calculated variable (water equivalent) should be.

  8. Airborne tunable diode laser spectrometer for trace-gas measurement in the lower stratosphere.

    PubMed

    Podolske, J; Loewenstein, M

    1993-09-20

    This paper describes the airborne tunable laser absorption spectrometer, a tunable diode laser instrument designed for in situ trace-gas measurement in the lower stratosphere from an ER-2 high-altitude research aircraft. Laser-wavelength modulation and second-harmonic detection are employed to achieve the required constituent detection sensitivity. The airborne tunable laser absorption spectrometer was used in two polar ozone campaigns, the Airborne Antarctic Ozone Experiment and the Airborne Arctic Stratospheric Expedition, and measured nitrous oxide with a response time of Is and an accuracy ≤ 10%.

  9. Diode - Pumped Nd:YAG Lidar for Airborne Cloud Measurements

    NASA Technical Reports Server (NTRS)

    Mehnert, A.; Halldorsson, TH.; Herrmann, H.; Haering, R.; Krichbaumer, W.; Streicher, J.; Werner, CH.

    1992-01-01

    This work is concerned with the experimental method used to separate scattering and to use it for the determination of cloud microphysical parameters. It is also the first airborne test of a lidar version related to the ATLID Program - ESA's scheduled spaceborne lidar. The already tested DLR microlidar was modified with the new diode-pumped laser and a faster data recording system was added. The system was used during the CLEOPATRA campaign in the DLR research aircraft Falcon 20 to measure cloud parameters. The diode pumped Nd:YAG laser we developed for the microlidar is a modification of the laser we introduced at the Lidar Congress at 'Laser 1991' in Munich. Various aspects of this work are discussed.

  10. Airborne Lidar Measurements of Aerosol Optical Properties During SAFARI-2000

    NASA Technical Reports Server (NTRS)

    McGill, M. J.; Hlavka, D. L.; Hart, W. D.; Welton, E. J.; Campbell, J. R.; Starr, David OC. (Technical Monitor)

    2002-01-01

    The Cloud Physics Lidar (CPL) operated onboard the NASA ER-2 high altitude aircraft during the SAFARI-2000 field campaign. The CPL provided high spatial resolution measurements of aerosol optical properties at both 1064 nm and 532 nm. We present here results of planetary boundary layer (PBL) aerosol optical depth analysis and profiles of aerosol extinction. Variation of optical depth and extinction are examined as a function of regional location. The wide-scale aerosol mapping obtained by the CPL is a unique data set that will aid in future studies of aerosol transport. Comparisons between the airborne CPL and ground-based MicroPulse Lidar Network (MPL-Net) sites are shown to have good agreement.

  11. An Intercomparison of Airborne VOC and PAN Measurements

    NASA Astrophysics Data System (ADS)

    Hansel, A.; Wisthaler, A.; Flocke, F.; Weinheimer, A.; Fall, R.; Goldan, P.; Hübler, G.; Fehsenfeld, F. C.

    2002-12-01

    As part of the Texas Air Quality Study (TexAQS 2000) an informal airborne intercomparison has been conducted to evaluate the state-of-the-art of fast-response, in-situ methods for analyzing Volatile Organic Compounds (VOCs) and peroxyacetyl nitrate (PAN). Instrumentation included a Proton-Transfer-Reaction Mass Spectrometer (PTR-MS), the Tropospheric Airborne Chromatograph for Oxy-hydrocarbons and Hydrocarbons (TACOH) and a gas chromatograph for PAN detection using electron capture (GC/ECD). The measurements were made in the Greater Houston area and East Texas in August/September 2000 during 13 flights with the NSF/NCAR ELECTRA aircraft. The intercomparison was conducted mainly in the boundary layer but included some encounters with air masses from the free troposphere. Final results from the intercomparison show that measurements of acetaldehyde, isoprene, the sum\\textsuperscript{*} of acetone and propanal, the sum\\textsuperscript{*} methyl vinyl ketone and methacrolein (\\textsuperscript{*} PTR-MS does not distinguish between isobaric species) and toluene agree very well. Poor agreement was achieved in the case of methanol and the underlying sensitivity problem in the PTR-MS or TACOH system is under investigation. The results of the PAN intercomparison indicate that the PTR-MS technique suffered from an interference most likely associated with the presence of peracetic acid in photochemically aged air. If this interfering signal was traced by periodically inserting a selective PAN scrubber (thermal decomposition) into the sample air stream and subtracted from the original signal, the corrected PTR-MS PAN data are in very good agreement with the GC/ECD results.

  12. Infrared heterodyne radiometer for airborne atmospheric transmittance measurements

    NASA Technical Reports Server (NTRS)

    Wolczok, J. M.; Lange, R. A.; Dinardo, A. J.

    1980-01-01

    An infrared heterodyne radiometer (IHR) was used to measure atmospheric transmittance at selected hydrogen fluoride (2.7 micrometer) and deuterium fluoride (3.8 micrometer) laser transitions. The IHR was installed aboard a KC-135 aircraft for an airborne atmospheric measurements program that used the sun as a backlighting source for the transmission measurements. The critical components are: a wideband indium antimonide (1nSb) photomixer, a CW HF/DF laser L0, a radiometric processor, and a 1900 K blackbody reference source. The measured heterodyne receiver sensitivity (NEP) is 1.3 x 10 to the -19th power W/Hz, which yields a calculated IHR temperature resolution accuracy of delta I sub S/-3 sub S = 0.005 for a source temperature of 1000 K and a total transmittance of 0.5. Measured atmospheric transmittance at several wavelengths and aircraft altitudes from 9.14 km (30,000 ft) to 13.72 km (45,000 ft) were obtained during the measurements program and have been compared with values predicted by the AFGL Atmospheric Line Parameter Compilation.

  13. Airborne flux measurements of biogenic volatile organic compounds over California

    NASA Astrophysics Data System (ADS)

    Misztal, P. K.; Karl, T.; Weber, R.; Jonsson, H. H.; Guenther, A. B.; Goldstein, A. H.

    2014-03-01

    Biogenic Volatile Organic Compound (BVOC) fluxes were measured onboard the CIRPAS Twin Otter aircraft as part of the California Airborne BVOC Emission Research in Natural Ecosystem Transects (CABERNET) campaign during June 2011. The airborne virtual disjunct eddy covariance (AvDEC) approach used measurements from a PTR-MS and a wind radome probe to directly determine fluxes of isoprene, MVK + MAC, methanol, monoterpenes, and MBO over ∼10 000 km of flight paths focusing on areas of California predicted to have the largest emissions of isoprene. The Fast Fourier Transform (FFT) approach was used to calculate fluxes over long transects of more than 15 km, most commonly between 50 and 150 km. The Continuous Wavelet Transformation (CWT) approach was used over the same transects to also calculate "instantaneous" fluxes with localization of both frequency and time independent of non-stationarities. Vertical flux divergence of isoprene is expected due to its relatively short lifetime and was measured directly using "racetrack" profiles at multiple altitudes. It was found to be linear and in the range 5% to 30% depending on the ratio of aircraft altitude to PBL height (z / zi). Fluxes were generally measured by flying consistently at 400 ± 50 m (a.g.l.) altitude, and extrapolated to the surface according to the determined flux divergence. The wavelet-derived surface fluxes of isoprene averaged to 2 km spatial resolution showed good correspondence to Basal Emission Factor (BEF) landcover datasets used to drive biogenic VOC (BVOC) emission models. The surface flux of isoprene was close to zero over Central Valley crops and desert shrublands, but was very high (up to 15 mg m-2 h-1) above oak woodlands, with clear dependence of emissions on temperature and oak density. Isoprene concentrations of up to 8 ppb were observed at aircraft height on the hottest days and over the dominant source regions. While isoprene emissions from agricultural crop regions, shrublands, and

  14. ALLDOS: a computer program for calculation of radiation doses from airborne and waterborne releases

    SciTech Connect

    Strenge, D.L.; Napier, B.A.; Peloquin, R.A.; Zimmerman, M.G.

    1980-10-01

    The computer code ALLDOS is described and instructions for its use are presented. ALLDOS generates tables of radiation doses to the maximum individual and the population in the region of the release site. Acute or chronic release of radionuclides may be considered to airborne and waterborne pathways. The code relies heavily on data files of dose conversion factors and environmental transport factors for generating the radiation doses. A source inventory data library may also be used to generate the release terms for each pathway. Codes available for preparation of the dose conversion factors are described and a complete sample problem is provided describing preparation of data files and execution of ALLDOS.

  15. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the workshop was on how the airborne community can assist in achieving the goals of the Global Change Research Program. The many activities that employ airborne platforms and sensors were discussed: platforms and instrument development; airborne oceanography; lidar research; SAR measurements; Doppler radar; laser measurements; cloud physics; airborne experiments; airborne microwave measurements; and airborne data collection.

  16. Interaction of airborne and structureborne noise radiated by plates. Volume 1: Analytical study

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1986-01-01

    The interaction of airborne and structureborne noise radiated by aircraft materials was examined. The theory and results of several computer simulations of the noise radiated by thin, isotropic, rectangular aluminum plates due to fully coherent combined acoustic and vibrational inputs is presented. The most significant finding was the extremely large influence that the relative phase between inputs has on the combined noise radiation of the plates. Phase dependent effects manifest themselves as cross terms in both the dynamic and acoustic portions of the analysis. Computer simulations show that these cross terms can radically alter the combined sound power radiated by plates constructed of aircraft-type materials. The results suggest that airborne-structureborne interactive effects could be responsible for a significant portion of the overall noise radiated by aircraft-type structures in the low frequency regime. This implies that previous analytical and experimental studies may have neglected an important physical phenomenon in the analayses of the interior noise of propeller dirven aircraft.

  17. Comparison of airborne lidar measurements with 420 kHz echo-sounder measurements of zooplankton.

    PubMed

    Churnside, James H; Thorne, Richard E

    2005-09-10

    Airborne lidar has the potential to survey large areas quickly and at a low cost per kilometer along a survey line. For this reason, we investigated the performance of an airborne lidar for surveys of zooplankton. In particular, we compared the lidar returns with echo-sounder measurements of zooplankton in Prince William Sound, Alaska. Data from eight regions of the Sound were compared, and the correlation between the two methods was 0.78. To obtain this level of agreement, a threshold was applied to the lidar return to remove the effects of scattering from phytoplankton.

  18. OPTIMIZING THE PAKS METHOD FOR MEASURING AIRBORNE ACROLEIN

    EPA Science Inventory

    Airborne acrolein is produced from the combustion of fuel and tobacco and is of concern due to its potential for respiratory tract irritation and other adverse health effects. DNPH active-sampling is a method widely used for sampling airborne aldehydes and ketones (carbonyls); ...

  19. ARM Airborne Carbon Measurements (ARM-ACME) and ARM-ACME 2.5 Final Campaign Reports

    SciTech Connect

    Biraud, S. C.; Tom, M. S.; Sweeney, C.

    2016-01-01

    We report on a 5-year multi-institution and multi-agency airborne study of atmospheric composition and carbon cycling at the Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Southern Great Plains (SGP) site, with scientific objectives that are central to the carbon-cycle and radiative-forcing goals of the U.S. Global Change Research Program and the North American Carbon Program (NACP). The goal of these measurements is to improve understanding of 1) the carbon exchange of the Atmospheric Radiation Measurement (ARM) SGP region; 2) how CO2 and associated water and energy fluxes influence radiative-forcing, convective processes, and CO2 concentrations over the ARM SGP region, and 3) how greenhouse gases are transported on continental scales.

  20. Relating Hyperspectral Airborne Data to Ground Measurements in a Complex and Discontinuous Canopy

    NASA Astrophysics Data System (ADS)

    Calleja, Javier F.; Hellmann, Christine; Mendiguren, Gorka; Punalekar, Suvarna; Peón, Juanjo; MacArthur, Alasdair; Alonso, Luis

    2015-12-01

    The work described in this paper is aimed at validating hyperspectral airborne reflectance data collected during the Regional Experiments For Land-atmosphere EXchanges (REFLEX) campaign. Ground reflectance data measured in a vineyard were compared with airborne reflectance data. A sampling strategy and subsequent ground data processing had to be devised so as to capture a representative spectral sample of this complex crop. A linear model between airborne and ground data was tried and statistically tested. Results reveal a sound correspondence between ground and airborne reflectance data ( R2 > 0.97), validating the atmospheric correction of the latter.

  1. Interaction of airborne and structure-borne noise radiated by plates

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1987-01-01

    The interaction of airborne and structure-borne noise radiated by aircraft structures is studied analytically and experimentally for the case of noise radiating from thin, isotropic, rectangular aluminum plates as a result of fully coherent, combined acoustic and vibrational inputs. Attention is given to the great influence of the relative phase between inputs on the combined noise radiation characteristics of the plates; these phase-dependent effects, which are manifest as cross-terms in both the dynamic and acoustic portions of the analysis, can radically alter the combined sound power radiated by airframe structure plates. Such interactive effects have heretofore been neglected in analyses of results from analytical and experimental studies of propeller-driven aircraft interior noise.

  2. Derivation of Cumulus Cloud Dimensions and Shape from the Airborne Measurements by the Research Scanning Polarimeter

    NASA Technical Reports Server (NTRS)

    Alexandrov, Mikhail D.; Cairns, Brian; Emde, Claudia; Ackerman, Andrew S.; Ottaviani, Matteo; Wasilewski, Andrzej P.

    2016-01-01

    The Research Scanning Polarimeter (RSP) is an airborne instrument, whose measurements have been extensively used for retrievals of microphysical properties of clouds. In this study we show that for cumulus clouds the information content of the RSP data can be extended by adding the macroscopic parameters of the cloud, such as its geometric shape, dimensions, and height above the ground. This extension is possible by virtue of the high angular resolution and high frequency of the RSP measurements, which allow for geometric constraint of the cloud's 2D cross section between a number of tangent lines of view. The retrieval method is tested on realistic 3D radiative transfer simulations and applied to actual RSP data.

  3. Relationship of surface fuels to fire radiative energy as estimated from airborne lidar and thermal infrared imaging

    NASA Astrophysics Data System (ADS)

    Hudak, A. T.; Dickinson, M. B.; Kremens, R.; Loudermilk, L.; O'Brien, J.; Satterberg, K.; Strand, E. K.; Ottmar, R. D.

    2013-12-01

    Longleaf pine stand structure and function are dependent on frequent fires, so fire managers maintain healthy longleaf pine ecosystems by frequently burning surface fuels with prescribed fires. Eglin Air Force Base (AFB) in the Florida panhandle boasts the largest remnant of longleaf pine forest, providing a productive setting for fire scientists to make multi-scale measurements of fuels, fire behavior, and fire effects in collaboration with Eglin AFB fire managers. Data considered in this analysis were collected in five prescribed burn units: two forested units burned in 2011 and a forested unit and two grassland units burned in 2012. Our objective was to demonstrate the linear relationship between biomass and fire energy that has been shown in the laboratory, but using two independent remotely sensed airborne datasets collected at the unit level: 1) airborne lidar flown over the burn units immediately prior to the burns, and 2) thermal infrared image time series flown over the burn units at 2-3 minute intervals. Airborne lidar point cloud data were reduced to 3 m raster metrics of surface vegetation height and cover, which were in turn used to map surface fuel loads at 3 m resolution. Plot-based measures of prefire surface fuels were used for calibration/validation. Preliminary results based on 2011 data indicate airborne lidar can explain ~30% of variation in surface fuel loads. Multi-temporal thermal infrared imagery (WASP) collected at 3 m resolution were calibrated to units of fire radiative power (FRP), using simultaneous FRP measures from ground-based radiometers, and then temporally integrated to estimate fire radiative energy (FRE) release at the unit level. Prior to AGU, FRP and FRE will be compared to estimates of the same variables derived from ground-based FLIR thermal infrared imaging cameras, each deployed with a nadir view from a tripod, at three sites per burn unit. A preliminary proof-of-concept, comparing FRE derived from a tripod-based FLIR (3

  4. Airborne High Spectral Resolution Lidar Aerosol Measurements during MILAGRO and TEXAQS/GOMACCS

    NASA Technical Reports Server (NTRS)

    Ferrare, Richard; Hostetler, Chris; Hair, John; Cook Anthony; Harper, David; Burton, Sharon; Clayton, Marian; Clarke, Antony; Russell, Phil; Redemann, Jens

    2007-01-01

    Two1 field experiments conducted during 2006 provided opportunities to investigate the variability of aerosol properties near cities and the impacts of these aerosols on air quality and radiative transfer. The Megacity Initiative: Local and Global Research Observations (MILAGRO) /Megacity Aerosol Experiment in Mexico City (MAX-MEX)/Intercontinental Chemical Transport Experiment-B (INTEX-B) joint experiment conducted during March 2006 investigated the evolution and transport of pollution from Mexico City. The Texas Air Quality Study (TEXAQS)/Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) (http://www.al.noaa.gov/2006/) conducted during August and September 2006 investigated climate and air quality in the Houston/Gulf of Mexico region. During both missions, the new NASA Langley airborne High Spectral Resolution Lidar (HSRL) was deployed on the NASA Langley B200 King Air aircraft and measured profiles of aerosol extinction, backscattering, and depolarization to: 1) characterize the spatial and vertical distributions of aerosols, 2) quantify aerosol extinction and optical thickness contributed by various aerosol types, 3) investigate aerosol variability near clouds, 4) evaluate model simulations of aerosol transport, and 5) assess aerosol optical properties derived from a combination of surface, airborne, and satellite measurements.

  5. Ground and Airborne Methane Measurements using Optical Parametric Amplifiers

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Numata, Kenji; Li, Steve; Wu, Stewart; Kawa, Stephan R.; Abshire, James; Dawsey, Martha; Ramanathan, Anand

    2012-01-01

    We report on an initial airborne demonstration of atmospheric methane column measurements at 1.65 micrometers using a widely tunable, seeded optical parametric amplifier (OPA) lidar and a photon counting detector. Methane is an important greenhouse gas and accurate knowledge of its sources and sinks is needed for climate modeling. Our lidar system uses 20 pulses at increasing wavelengths and integrated path differential absorption (IPDA) to map a methane line at 1650.9 nanometers. The wavelengths are generated by using a Nd:YAG pump laser at 1064.5 nanometers and distributed feedback diode laser at 1650.9 nanometers and a periodically-poled lithium niobate (PPLN) crystal. The pulse width was 3 nanoseconds and the pulse repetition rate was 6.28 KHz. The outgoing energy was approximately 13 microJoules/pulse. A commercial 20 nanometer diameter fiber-coupled telescope with a photon counting detector operated in analog mode with a 0.8 nanometer bandpass filter was used as the lidar receiver. The lidar system was integrated on NASA's DC-8 flying laboratory, based at Dryden Airborne operations Facility (DAOF) in Palmdale CA. Three flights were performed in the central valley of California. Each flight lasted about 2.5 hours and it consisted of several flight segments at constant altitudes at approximately 3, 4.5, 6, 7.6, 9.1, 10.6 km (l0, 15, 20, 25, 30, 35 kft). An in-situ cavity ring down spectrometer made by Picarro Inc. was flown along with the lidar instrument provided us with the "truth" i.e. the local CH4, CO2 and H2O concentrations at the constant flight altitude segments. Using the aircraft's altitude, GPS, and meteorological data we calculated the theoretical differential optical depth of the methane absorption at increasing altitudes. Our results showed good agreement between the experimentally derived optical depth measurements from the lidar instrument and theoretical calculations as the flight altitude was increased from 3 to 10.6 kilometers, assuming a

  6. Measuring Radiant Emissions from Entire Prescribed Fires with Ground, Airborne and Satellite Sensors RxCADRE 2012

    NASA Technical Reports Server (NTRS)

    Dickinson, Matthew B.; Hudak, Andrew T.; Zajkowski, Thomas; Loudermilk, E. Louise; Schroeder, Wilfrid; Ellison, Luke; Kremens, Robert L.; Holley, William; Martinez, Otto; Paxton, Alexander; Bright, Benjamin C.; O'Brien, Joseph J.; Hornsby, Benjamin; Ichoku, Charles; Faulring, Jason; Gerace, Aaron; Peterson, David; Mauceri, Joseph

    2015-01-01

    Characterising radiation from wildland fires is an important focus of fire science because radiation relates directly to the combustion process and can be measured across a wide range of spatial extents and resolutions. As part of a more comprehensive set of measurements collected during the 2012 Prescribed Fire Combustion and Atmospheric Dynamics Research (RxCADRE) field campaign, we used ground, airborne and spaceborne sensors to measure fire radiative power (FRP) from whole fires, applying different methods to small (2 ha) and large (.100 ha) burn blocks. For small blocks (n1/46), FRP estimated from an obliquely oriented long-wave infrared (LWIR) camera mounted on a boom lift were compared with FRP derived from combined data from tower-mounted radiometers and remotely piloted aircraft systems (RPAS). For large burn blocks (n1/43), satellite FRP measurements from the Moderate-resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) sensors were compared with near-coincident FRP measurements derived from a LWIR imaging system aboard a piloted aircraft. We describe measurements and consider their strengths and weaknesses. Until quantitative sensors exist for small RPAS, their use in fire research will remain limited. For oblique, airborne and satellite sensors, further FRP measurement development is needed along with greater replication of coincident measurements, which we show to be feasible.

  7. Airborne Double Pulsed 2-Micron IPDA Lidar for Atmospheric CO2 Measurement

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Singh, Upendra

    2015-01-01

    We have developed an airborne 2-micron Integrated Path Differential Absorption (IPDA) lidar for atmospheric CO2 measurements. The double pulsed, high pulse energy lidar instrument can provide high-precision CO2 column density measurements.

  8. Airborne flux measurements of Biogenic Isoprene over California

    SciTech Connect

    Misztal, P.; Karl, Thomas G.; Weber, Robin; Jonsson, H. H.; Guenther, Alex B.; Goldstein, Allen H.

    2014-10-10

    Biogenic Volatile Organic Compound (BVOC) fluxes were measured onboard the CIRPAS Twin Otter aircraft as part of the California Airborne BVOC Emission Research in Natural Ecosystem Transects (CABERNET) campaign during June 2011. The airborne virtual disjunct eddy covariance (AvDEC) approach used measurements from a PTR-MS and a wind radome probe to directly determine fluxes of isoprene, MVK+MAC, methanol, monoterpenes, and MBO over ~10,000-km of flight paths focusing on areas of California predicted to have the largest emissions of isoprene. The Fast Fourier Transform (FFT) approach was used to calculate fluxes over long transects of more than 15 km, most commonly between 50 and 150 km. The Continuous Wavelet Transformation (CWT) approach was used over the same transects to also calculate "instantaneous" fluxes with localization of both frequency and time independent of non-stationarities. Vertical flux divergence of isoprene is expected due to its relatively short lifetime and was measured directly using "racetrack" profiles at multiple altitudes. It was found to be linear and in the range 5% to 30% depending on the ratio of aircraft altitude to PBL height (z/zi). Fluxes were generally measured by flying consistently 1 at 400 m ±50 m (a.g.l.) altitude, and extrapolated to the surface according to the determined flux divergence. The wavelet-derived surface fluxes of isoprene averaged to 2 km spatial resolution showed good correspondence to Basal Emission Factor (BEF) landcover datasets used to drive biogenic VOC (BVOC) emission models. The surface flux of isoprene was close to zero over Central Valley crops and desert shrublands, but was very high (up to 15 mg m-2 h-1) above oak woodlands, with clear dependence of emissions on temperature and oak density. Isoprene concentrations of up to 8 ppb were observed at aircraft height on the hottest days and over the dominant source regions. While isoprene emissions from agricultural crop regions, shrublands, and

  9. Airborne measurements of biomass burning aerosol distribution and composition in the springtime Arctic 2008

    NASA Astrophysics Data System (ADS)

    Thornberry, T.; Froyd, K. D.; Murphy, D. M.; Thomson, D. S.; Brock, C. A.; Cozic, J.; Warneke, C.; Degouw, J.; Middlebrook, A. M.; Bahreini, R.; Brioude, J.

    2008-12-01

    The springtime Arctic troposphere in 2008 was characterized by high concentrations of biomass burning aerosol. During the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) campaign, airborne measurements of aerosol composition by the NOAA single particle mass spectrometer instrument (PALMS) identified biomass burning particles using an established composition tracer. Fires in northern Asia produced biomass burning aerosol that were transported to the Arctic within 3-12 days. Concentrations of biomass burning aerosols were elevated not only within well defined plumes, but also regionally throughout the Arctic. Above the boundary layer, biomass burning particles dominated the total aerosol volume and were largely responsible for the Arctic Haze observed during the period of study. The composition of plume aerosols varied according to source region, transport time, and anthropogenic influence.

  10. Volumetric pattern analysis of fuselage-mounted airborne antennas. Ph.D. Thesis; [prediction analysis techniques for antenna radiation patterns of microwave antennas on commercial aircraft

    NASA Technical Reports Server (NTRS)

    Yu, C. L.

    1976-01-01

    A volumetric pattern analysis of fuselage-mounted airborne antennas at high frequencies was investigated. The primary goal of the investigation was to develop a numerical solution for predicting radiation patterns of airborne antennas in an accurate and efficient manner. An analytical study of airborne antenna pattern problems is presented in which the antenna is mounted on the fuselage near the top or bottom. Since this is a study of general-type commercial aircraft, the aircraft was modeled in its most basic form. The fuselage was assumed to be an infinitely long perfectly conducting elliptic cylinder in its cross-section and a composite elliptic cylinder in its elevation profile. The wing, cockpit, stabilizers (horizontal and vertical) and landing gear are modeled by "N" sided bent or flat plates which can be arbitrarily attached to the fuselage. The volumetric solution developed utilizes two elliptic cylinders, namely, the roll plane and elevation plane models to approximate the principal surface profile (longitudinal and transverse) at the antenna location. With the belt concept and the aid of appropriate coordinate system transformations the solution can be used to predict the volumetric patterns of airborne antennas in an accurate and efficient manner. Applications of this solution to various airborne antenna problems show good agreement with scale model measurements. Extensive data are presented for a microwave landing antenna system.

  11. Using airborne LIDAR to measure tides and river slope

    NASA Astrophysics Data System (ADS)

    Talke, S. A.; Hudson, A.; Chickadel, C. C.; Farquharson, G.; Jessup, A. T.

    2014-12-01

    The spatial variability of tides and the tidally-averaged water-level is often poorly resolved in shallow waters, despite its importance in validating models and interpreting dynamics. In this contribution we explore using airborne LIDAR to remotely observe tides and along-river slope in the Columbia River estuary (CRE). Using an airplane equipped with LIDAR, differential GPS, and an infra-red camera, we flew 8 longitudinal transects over a 50km stretch of the CRE over a 14 hour period in June 2013. After correcting for airplane elevation, pitch and roll and median filtering over 1km blocks, a spatially-resolved data set of relative water level was generated. Results show the tide (amplitude 2m) propagating upstream at the expected phase velocity. A sinusoid with 2 periods (12.4 and 24 hours) was next fit to data to produce a smooth tide and extract the mean slope. Comparison with 4 tide gauges indicates first order agreement with measured tides (rms error 0.1m), and confirms that a substantial sub-tidal gradient exists in the CRE. This proof-of-concept experiment indicates that remote sensing of tides in coastal areas is feasible, with possible applications such as improving bathymetric surveys or inferring water depths.

  12. The NASA Airborne Tropical TRopopause EXperiment (ATTREX):High-Altitude Aircraft Measurements in the Tropical Western Pacific

    NASA Technical Reports Server (NTRS)

    Jensen, E. J.; Pfister, L.; Jordan, D. E.; Bui, T. V.; Ueyama, R.; Singh, H. B.; Lawson, P.; Thornberry, T.; Diskin, G.; McGill, M.; Pittman, J.; Atlas, E.; Kim, J.

    2016-01-01

    The February through March 2014 deployment of the NASA Airborne Tropical TRopopause EXperiment (ATTREX) provided unique in situ measurements in the western Pacific Tropical Tropopause Layer (TTL). Six flights were conducted from Guam with the long-range, high-altitude, unmanned Global Hawk aircraft. The ATTREX Global Hawk payload provided measurements of water vapor, meteorological conditions, cloud properties, tracer and chemical radical concentrations, and radiative fluxes. The campaign was partially coincident with the CONTRAST and CAST airborne campaigns based in Guam using lower-altitude aircraft The ATTREX dataset is being used for investigations of TTL cloud, transport, dynamical, and chemical processes as well as for evaluation and improvement of global-model representations of TTL processes.

  13. Mapping methane emission sources over California based on airborne measurements

    NASA Astrophysics Data System (ADS)

    Karl, T.; Guha, A.; Peischl, J.; Misztal, P. K.; Jonsson, H.; Goldstein, A. H.; Ryerson, T. B.

    2011-12-01

    The California Global Warming Solutions Act of 2006 (AB 32) has created a need to accurately characterize the emission sources of various greenhouse gases (GHGs) and verify the existing state GHG inventory. Methane (CH4) is a major GHG with a global warming potential of 20 times that of CO2 and currently constitutes about 6% of the total statewide GHG emissions on a CO2 equivalent basis. Some of the major methane sources in the state are area sources where methane is biologically produced (e.g. dairies, landfills and waste treatment plants) making bottom-up estimation of emissions a complex process. Other potential sources include fugitive emissions from oil extraction processes and natural gas distribution network, emissions from which are not well-quantified. The lack of adequate field measurement data to verify the inventory and provide independently generated estimates further contributes to the overall uncertainty in the CH4 inventory. In order to gain a better perspective of spatial distribution of major CH4 sources in California, a real-time measurement instrument based on Cavity Ring Down Spectroscopy (CRDS) was installed in a Twin Otter aircraft for the CABERNET (California Airborne BVOC Emissions Research in Natural Ecosystems Transects) campaign, where the driving research goal was to understand the spatial distribution of biogenic VOC emissions. The campaign took place in June 2011 and encompassed over forty hours of airborne CH4 and CO2 measurements during eight unique flights which covered much of the Central Valley and its eastern edge, the Sacramento-San Joaquin delta and the coastal range. The coincident VOC measurements, obtained through a high frequency proton transfer reaction mass spectrometer (PTRMS), aid in CH4 source identification. High mixing ratios of CH4 (> 2000 ppb) are observed consistently in all the flight transects above the Central Valley. These high levels of CH4 are accompanied by high levels of methanol which is an important

  14. Alexandrite laser transmitter development for airborne water vapor DIAL measurements

    NASA Technical Reports Server (NTRS)

    Chyba, Thomas H.; Ponsardin, Patrick; Higdon, Noah S.; DeYoung, Russell J.; Browell, Edward V.

    1995-01-01

    In the DIAL technique, the water vapor concentration profile is determined by analyzing the lidar backscatter signals for laser wavelengths tuned 'on' and 'off' a water vapor absorption line. Desired characteristics of the on-line transmitted laser beam include: pulse energy greater than or equal to 100 mJ, high-resolution tuning capability (uncertainty less than 0.25 pm), good spectral stability (jitter less than 0.5 pm about the mean), and high spectral purity (greater than 99 percent). The off-line laser is generally detuned less than 100 pm away from the water vapor line. Its spectral requirements are much less stringent. In our past research, we developed and demonstrated the airborne DIAL technique for water vapor measurements in the 720-nm spectral region using a system based on an alexandrite laser as the transmitter for the on-line wavelength and a Nd:YAG laser-pumped dye laser for the off-line wavelength. This off-line laser has been replaced by a second alexandrite laser. Diode lasers are used to injection seed both lasers for frequency and linewidth control. This eliminates the need for the two intracavity etalons utilized in our previous alexandrite laser and thereby greatly reduces the risk of optical damage. Consequently, the transmitted pulse energy can be substantially increased, resulting in greater measurement range, higher data density, and increased measurement precision. In this paper, we describe the diode injection seed source, the two alexandrite lasers, and the device used to line lock the on-line seed source to the water vapor absorption feature.

  15. The Atmospheric Radiation Measurement Program May 2003 Intensive Operations Period Examining Aerosol Properties and Radiative Influences: Preface to Special Section

    NASA Technical Reports Server (NTRS)

    Ferrare, Richard; Feingold, Graham; Ghan, Steven; Ogren, John; Schmid, Beat; Schwartz, Stephen E.; Sheridan, Pat

    2006-01-01

    Atmospheric aerosols influence climate by scattering and absorbing radiation in clear air (direct effects) and by serving as cloud condensation nuclei, modifying the microphysical properties of clouds, influencing radiation and precipitation development (indirect effects). Much of present uncertainty in forcing of climate change is due to uncertainty in the relations between aerosol microphysical and optical properties and their radiative influences (direct effects) and between microphysical properties and their ability to serve as cloud condensation nuclei at given supersaturations (indirect effects). This paper introduces a special section that reports on a field campaign conducted at the Department of Energy Atmospheric Radiation Measurement site in North Central Oklahoma in May, 2003, examining these relations using in situ airborne measurements and surface-, airborne-, and space-based remote sensing.

  16. Measurement of airborne particle concentrations near the Sunset Crater volcano, Arizona.

    PubMed

    Benke, Roland R; Hooper, Donald M; Durham, James S; Bannon, Donald R; Compton, Keith L; Necsoiu, Marius; McGinnis, Ronald N

    2009-02-01

    Direct measurements of airborne particle mass concentrations or mass loads are often used to estimate health effects from the inhalation of resuspended contaminated soil. Airborne particle mass concentrations were measured using a personal sampler under a variety of surface-disturbing activities within different depositional environments at both volcanic and nonvolcanic sites near the Sunset Crater volcano in northern Arizona. Focused field investigations were performed at this analog site to improve the understanding of natural and human-induced processes at Yucca Mountain, Nevada. The level of surface-disturbing activity was found to be the most influential factor affecting the measured airborne particle concentrations, which increased over three orders of magnitude relative to ambient conditions. As the surface-disturbing activity level increased, the particle size distribution and the majority of airborne particle mass shifted from particles with aerodynamic diameters less than 10 mum (0.00039 in) to particles with aerodynamic diameters greater than 10 mum (0.00039 in). Under ambient conditions, above average wind speeds tended to increase airborne particle concentrations. In contrast, stronger winds tended to decrease airborne particle concentrations in the breathing zone during light and heavy surface-disturbing conditions. A slight increase in the average airborne particle concentration during ambient conditions was found above older nonvolcanic deposits, which tended to be finer grained than the Sunset Crater tephra deposits. An increased airborne particle concentration was realized when walking on an extremely fine-grained deposit, but the sensitivity of airborne particle concentrations to the resuspendible fraction of near-surface grain mass was not conclusive in the field setting when human activities disturbed the bulk of near-surface material. Although the limited sample size precluded detailed statistical analysis, the differences in airborne particle

  17. Real-time airborne gamma-ray background estimation using NASVD with MLE and radiation transport for calibration

    NASA Astrophysics Data System (ADS)

    Kulisek, J. A.; Schweppe, J. E.; Stave, S. C.; Bernacki, B. E.; Jordan, D. V.; Stewart, T. N.; Seifert, C. E.; Kernan, W. J.

    2015-06-01

    Helicopter-mounted gamma-ray detectors can provide law enforcement officials the means to quickly and accurately detect, identify, and locate radiological threats over a wide geographical area. The ability to accurately distinguish radiological threat-generated gamma-ray signatures from background gamma radiation in real time is essential in order to realize this potential. This problem is non-trivial, especially in urban environments for which the background may change very rapidly during flight. This exacerbates the challenge of estimating background due to the poor counting statistics inherent in real-time airborne gamma-ray spectroscopy measurements. To address this challenge, we have developed a new technique for real-time estimation of background gamma radiation from aerial measurements without the need for human analyst intervention. The method can be calibrated using radiation transport simulations along with data from previous flights over areas for which the isotopic composition need not be known. Over the examined measured and simulated data sets, the method generated accurate background estimates even in the presence of a strong, 60Co source. The potential to track large and abrupt changes in background spectral shape and magnitude was demonstrated. The method can be implemented fairly easily in most modern computing languages and environments.

  18. EXOMARS IRAS (DOSE) radiation measurements.

    NASA Astrophysics Data System (ADS)

    Federico, C.; Di Lellis, A. M.; Fonte, S.; Pauselli, C.; Reitz, G.; Beaujean, R.

    The characterization and the study of the radiations on their interaction with organic matter is of great interest in view of the human exploration on Mars. The Ionizing RAdiation Sensor (IRAS) selected in the frame of the ExoMars/Pasteur ESA mission is a lightweight particle spectrometer combining various techniques of radiation detection in space. It characterizes the first time the radiation environment on the Mars surface, and provide dose and dose equivalent rates as precursor information absolutely necessary to develop ways to mitigate the radiation risks for future human exploration on Mars. The Martian radiation levels are much higher than those found on Earth and they are relatively low for space. Measurements on the surface will show if they are similar or not to those seen in orbit (modified by the presence of ``albedo'' neutrons produced in the regolith and by the thin Martian atmosphere). IRAS consists of a telescope based on segmented silicon detectors of about 40\\userk\\milli\\metre\\user;k diameter and 300\\user;k\\micro\\metre\\user;k thickness, a segmented organic scintillator, and of a thermoluminescence dosimeter. The telescope will continuously monitor temporal variation of the particle count rate, the dose rate, particle and LET (Linear Energy Transfer) spectra. Tissue equivalent BC430 scintillator material will be used to measure the neutron dose. Neutrons are selected by a criteria requiring no signal in the anti-coincidence. Last, the passive thermoluminescence dosimeter, based on LiF:Mg detectors, regardless the on board operation timing, will measure the total dose accumulated during the exposure period and due to beta and gamma radiation, with a responsivity very close to that of a human tissue.

  19. Airborne particle concentrations at schools measured at different spatial scales

    NASA Astrophysics Data System (ADS)

    Buonanno, G.; Fuoco, F. C.; Morawska, L.; Stabile, L.

    2013-03-01

    Potential adverse effects on children health may result from school exposure to airborne particles. To address this issue, measurements in terms of particle number concentration, particle size distribution and black carbon (BC) concentrations were performed in three school buildings in Cassino (Italy) and its suburbs, outside and inside of the classrooms during normal occupancy and use. Additional time resolved information was gathered on ventilation condition, classroom activity, and traffic count data around the schools were obtained using a video camera. Across the three investigated school buildings, the outdoor and indoor particle number concentration monitored down to 4 nm and up to 3 μm ranged from 2.8 × 104 part cm-3 to 4.7 × 104 part cm-3 and from 2.0 × 104 part cm-3 to 3.5 × 104 part cm-3, respectively. The total particle concentrations were usually higher outdoors than indoors, because no indoor sources were detected. I/O measured was less than 1 (varying in a relatively narrow range from 0.63 to 0.74), however one school exhibited indoor concentrations higher than outdoor during the morning rush hours. Particle size distribution at the outdoor site showed high particle concentrations in different size ranges, varying during the day; in relation to the starting and finishing of school time two modes were found. BC concentrations were 5 times higher at the urban school compared with the suburban and suburban-to-urban differences were larger than the relative differences of ultrafine particle concentrations.

  20. Simple method for measuring vibration amplitude of high power airborne ultrasonic transducer: using thermo-couple.

    PubMed

    Saffar, Saber; Abdullah, Amir

    2014-03-01

    Vibration amplitude of transducer's elements is the influential parameters in the performance of high power airborne ultrasonic transducers to control the optimum vibration without material yielding. The vibration amplitude of elements of provided high power airborne transducer was determined by measuring temperature of the provided high power airborne transducer transducer's elements. The results showed that simple thermocouples can be used both to measure the vibration amplitude of transducer's element and an indicator to power transmission to the air. To verify our approach, the power transmission to the air has been investigated by other common method experimentally. The experimental results displayed good agreement with presented approach.

  1. Airborne flux measurements of biogenic isoprene over California

    NASA Astrophysics Data System (ADS)

    Misztal, P. K.; Karl, T.; Weber, R.; Jonsson, H. H.; Guenther, A. B.; Goldstein, A. H.

    2014-10-01

    Biogenic isoprene fluxes were measured onboard the CIRPAS Twin Otter aircraft as part of the California Airborne Biogenic volatile organic compound (BVOC) Emission Research in Natural Ecosystem Transects (CABERNET) campaign during June 2011. The airborne virtual disjunct eddy covariance (AvDEC) approach used measurements from a proton transfer reaction mass spectrometer (PTR-MS) and a wind radome probe to directly determine fluxes of isoprene over 7400 km of flight paths focusing on areas of California predicted to have the largest emissions. The fast Fourier transform (FFT) approach was used to calculate fluxes of isoprene over long transects of more than 15 km, most commonly between 50 and 150 km. The continuous wavelet transformation (CWT) approach was used over the same transects to also calculate instantaneous isoprene fluxes with localization of both frequency and time independent of non-stationarities. Fluxes were generally measured by flying consistently at 400 m ± 50 m (a.g.l.) altitude, and extrapolated to the surface according to the determined flux divergence determined in the racetrack-stacked profiles. The wavelet-derived surface fluxes of isoprene averaged to 2 km spatial resolution showed good correspondence to basal emission factor (BEF) land-cover data sets used to drive BVOC emission models. The surface flux of isoprene was close to zero over Central Valley crops and desert shrublands, but was very high (up to 15 mg m-2 h-1) above oak woodlands, with clear dependence of emissions on temperature and oak density. Isoprene concentrations of up to 8 ppb were observed at aircraft height on the hottest days and over the dominant source regions. Even though the isoprene emissions from agricultural crop regions, shrublands, and coniferous forests were extremely low, observations at the Walnut Grove tower south of Sacramento demonstrate that isoprene oxidation products from the high emitting regions in the surrounding oak woodlands accumulate at night in

  2. Aerosol Optical Depth Measurements by Airborne Sun Photometer in SOLVE II: Comparisons to SAGE III, POAM III and Airborne Spectrometer Measurements

    NASA Technical Reports Server (NTRS)

    Russell, P.; Livingston, J.; Schmid, B.; Eilers, J.; Kolyer, R.; Redemann, J.; Ramirez, S.; Yee, J-H.; Swartz, W.; Shetter, R.

    2004-01-01

    The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) measured solar-beam transmission on the NASA DC-8 during the Second SAGE III Ozone Loss and Validation Experiment (SOLVE II). This paper presents AATS-14 results for multiwavelength aerosol optical depth (AOD), including its spatial structure and comparisons to results from two satellite sensors and another DC-8 instrument. These are the Stratospheric Aerosol and Gas Experiment III (SAGE III), the Polar Ozone and Aerosol Measurement III (POAM III) and the Direct beam Irradiance Airborne Spectrometer (DIAS).

  3. 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%.

  4. Validation of LIRIC aerosol concentration retrievals using airborne measurements during a biomass burning episode over Athens

    NASA Astrophysics Data System (ADS)

    Kokkalis, Panagiotis; Amiridis, Vassilis; Allan, James D.; Papayannis, Alexandros; Solomos, Stavros; Binietoglou, Ioannis; Bougiatioti, Aikaterini; Tsekeri, Alexandra; Nenes, Athanasios; Rosenberg, Philip D.; Marenco, Franco; Marinou, Eleni; Vasilescu, Jeni; Nicolae, Doina; Coe, Hugh; Bacak, Asan; Chaikovsky, Anatoli

    2017-01-01

    In this paper we validate the Lidar-Radiometer Inversion Code (LIRIC) retrievals of the aerosol concentration in the fine mode, using the airborne aerosol chemical composition dataset obtained over the Greater Athens Area (GAA) in Greece, during the ACEMED campaign. The study focuses on the 2nd of September 2011, when a long-range transported smoke layer was observed in the free troposphere over Greece, in the height range from 2 to 3 km. CIMEL sun-photometric measurements revealed high AOD ( 0.4 at 532 nm) and Ångström exponent values ( 1.7 at 440/870 nm), in agreement with coincident ground-based lidar observations. Airborne chemical composition measurements performed over the GAA, revealed increased CO volume concentration ( 110 ppbv), with 57% sulphate dominance in the PM1 fraction. For this case, we compare LIRIC retrievals of the aerosol concentration in the fine mode with the airborne Aerosol Mass Spectrometer (AMS) and Passive Cavity Aerosol Spectrometer Probe (PCASP) measurements. Our analysis shows that the remote sensing retrievals are in a good agreement with the measured airborne in-situ data from 2 to 4 km. The discrepancies observed between LIRIC and airborne measurements at the lower troposphere (below 2 km), could be explained by the spatial and temporal variability of the aerosol load within the area where the airborne data were averaged along with the different time windows of the retrievals.

  5. 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.

  6. Determination of precipitation profiles from airborne passive microwave radiometric measurements

    NASA Technical Reports Server (NTRS)

    Kummerow, Christian; Hakkarinen, Ida M.; Pierce, Harold F.; Weinman, James A.

    1991-01-01

    This study presents the first quantitative retrievals of vertical profiles of precipitation derived from multispectral passive microwave radiometry. Measurements of microwave brightness temperature (Tb) obtained by a NASA high-altitude research aircraft are related to profiles of rainfall rate through a multichannel piecewise-linear statistical regression procedure. Statistics for Tb are obtained from a set of cloud radiative models representing a wide variety of convective, stratiform, and anvil structures. The retrieval scheme itself determines which cloud model best fits the observed meteorological conditions. Retrieved rainfall rate profiles are converted to equivalent radar reflectivity for comparison with observed reflectivities from a ground-based research radar. Results for two case studies, a stratiform rain situation and an intense convective thunderstorm, show that the radiometrically derived profiles capture the major features of the observed vertical structure of hydrometer density.

  7. A Characterization of Arctic Aerosols as Derived from Airborne Observations and their Influence on the Surface Radiation Budget

    NASA Astrophysics Data System (ADS)

    Herber, A.; Stone, R.; Liu, P. S.; Li, S.; Sharma, S.; Neuber, R.; Birnbaumn, G.; Vitale, V.

    2011-12-01

    Arctic climate is influenced by aerosols that affect the radiation balance at the surface and within the atmosphere. Impacts depend on the composition and concentration of aerosols that determine opacity, which is quantified by the measure of aerosol optical depth (AOD). During winter and spring, aerosols are transported into the Arctic from lower latitude industrial regions. Trans-Arctic flight missions PAMARCMiP (Polar Airborne Measurements and Arctic Regional Climate Model Simulation Project) of the German POLAR 5 during spring 2009 and spring 2011 provided opportunities to collect a comprehensive data set from which properties of the aerosol were derived, including AOD. Measurements were made from near the surface to over 4 km in altitude during flights between Svalbard, Norway and Pt. Barrow, Alaska. These, along with measurements of particle size and concentration, and black carbon content (BC) provide a three-dimensional characterization of the aerosols encountered along track. The horizontal and vertical distribution of Arctic haze, in particular, was evaluated. During April 2009, the Arctic atmosphere was variably turbid with total column AOD (at 500 nm) ranging from ~ 0.12 to > 0.35, where clean background values are typically < 0.06 (Stone et al., 2010). The haze was concentrated within and just above the surface-based temperature inversion layer. Few, distinct elevated aerosol layers were observed, also with an aerosol airborne Lidar. The presence of these haze layers in the Arctic atmosphere during spring reduced the diurnally averaged net shortwave irradiance, which can cause cooling of the surface, depending on its Albedo (reflectivity). An overview of both campaigns will be given with results presented in the context of historical observations and current thinking about the impact aerosols have on the Arctic climate. Stone, R.S., A. Herber, V. Vitale, M. Mazzola, A. Lupi, R. Schnell, E.G. Dutton, P. Liu, S.M. Li, K. Dethloff, A. Lampert, C. Ritter

  8. Airborne measurements of cloud forming nuclei and aerosol particles at Kennedy Space Center, Florida

    NASA Technical Reports Server (NTRS)

    Radke, L. F.; Langer, G.; Hindman, E. E., II

    1978-01-01

    Results of airborne measurements of the sizes and concentrations of aerosol particles, ice nuclei, and cloud condensation nuclei that were taken at Kennedy Space Center, Florida, are presented along with a detailed description of the instrumentation and measuring capabilities of the University of Washington airborne measuring facility (Douglas B-23). Airborne measurements made at Ft. Collins, Colorado, and Little Rock, Arkansas, during the ferry of the B-23 are presented. The particle concentrations differed significantly between the clean air over Ft. Collins and the hazy air over Little Rock and Kennedy Space Center. The concentrations of cloud condensation nuclei over Kennedy Space Center were typical of polluted eastern seaboard air. Three different instruments were used to measure ice nuclei: one used filters to collect the particles, and the others used optical and acoustical methods to detect ice crystals grown in portable cloud chambers. A comparison of the ice nucleus counts, which are in good agreement, is presented.

  9. Airborne 2-Micron Double Pulsed Direct Detection IPDA Lidar for Atmospheric CO2 Measurement

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Petros, Mulugeta; Refaat, Tamer F.; Reithmaier, Karl; Remus, Ruben; Singh, Upendra; Johnson, Will; Boyer, Charlie; Fay, James; Johnston, Susan; Murchison, Luke

    2015-01-01

    An airborne 2-micron double-pulsed Integrated Path Differential Absorption (IPDA) lidar has been developed for atmospheric CO2 measurements. This new 2-miron pulsed IPDA lidar has been flown in spring of 2014 for total ten flights with 27 flight hours. It provides high precision measurement capability by unambiguously eliminating contamination from aerosols and clouds that can bias the IPDA measurement.

  10. Real-time remote detection and measurement for airborne imaging spectroscopy: a case study with methane

    NASA Astrophysics Data System (ADS)

    Thompson, D. R.; Leifer, I.; Bovensmann, H.; Eastwood, M.; Fladeland, M.; Frankenberg, C.; Gerilowski, K.; Green, R. O.; Kratwurst, S.; Krings, T.; Luna, B.; Thorpe, A. K.

    2015-06-01

    Localized anthropogenic sources of atmospheric CH4 are highly uncertain and temporally variable. Airborne remote measurement is an effective method to detect and quantify these emissions. In a campaign context, the science yield can be dramatically increased by real-time retrievals that allow operators to coordinate multiple measurements of the most active areas. This can improve science outcomes for both single- and multiple-platform missions. We describe a case study of the NASA/ESA CO2 and Methane Experiment (COMEX) campaign in California during June and August/September 2014. COMEX was a multi-platform campaign to measure CH4 plumes released from anthropogenic sources including oil and gas infrastructure. We discuss principles for real-time spectral signature detection and measurement, and report performance on the NASA Next Generation Airborne Visible Infrared Spectrometer (AVIRIS-NG). AVIRIS-NG successfully detected CH4 plumes in real-time at Gb s-1 data rates, characterizing fugitive releases in concert with other in situ and remote instruments. The teams used these real-time CH4 detections to coordinate measurements across multiple platforms, including airborne in situ, airborne non-imaging remote sensing, and ground-based in situ instruments. To our knowledge this is the first reported use of real-time trace gas signature detection in an airborne science campaign, and presages many future applications.

  11. Hydrometeor discrimination in melting layer using multiparameter airborne radar measurement

    NASA Technical Reports Server (NTRS)

    Kumagai, H.; Meneghini, R.; Kozu, T.

    1992-01-01

    Results from a multiparameter airborne radar/radiometer experiment (the Typhoon experiment) are presented. The experiment was conducted in the western Pacific with the NASA DC-8 aircraft, in which a dual-wavelength at X-band and Ka-band and dual-polarization at X-band radar was installed. The signatures of dBZ(X), dBZ(Ka), LDR (linear depolarization ratio) at X-band and DZ=dBZ(X)-dBZ(Ka) are discussed for the data obtained in the penetration of the typhoon Flo. With emphasis on discrimination of hydrometeor particles, some statistical features of the brightband in stratiform rain are discussed.

  12. Airborne measurements of launch vehicle effluent: Launch of Space Shuttle (STS-1) on 12 April 1981

    NASA Technical Reports Server (NTRS)

    Gregory, G. L.; Woods, D. C.; Sebacher, D. I.

    1983-01-01

    Launch vehicle effluent environmental impact activities from the first space shuttle (STS-1) included airborne measurements within the exhaust cloud from about 9 min after launch (T + 9) to T + 120 min. Measurements included total hydrogen chloride (gaseous plus aqueous) concentrations, particulate concentrations, temperature, and dewpoint temperature. The airborne measurements are summarized. The physical growth and behavior of exhaust clouds is presented as well as the results of laboratory analysis of elemental composition of particulate samples collected by the aircraft. Observed results from the STS-1 launch are compared with earlier Titan III results. Shuttle effluent concentrations are found to be within the range of Titan III observations.

  13. Sampling and analysis method for measuring airborne coal dust mass in mixtures with limestone (rock) dust

    PubMed Central

    Barone, T. L.; Patts, J. R.; Janisko, S. J.; Colinet, J. F.; Patts, L. D.; Beck, T. W.; Mischler, S. E.

    2016-01-01

    Airborne coal dust mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone dust, which is an incombustible dust applied to prevent the propagation of dust explosions. To accurately measure the coal portion of this mixed airborne dust, the National Institute for Occupational Safety and Health (NIOSH) developed a sampling and analysis protocol that used a stainless steel cassette adapted with an isokinetic inlet and the low temperature ashing (LTA) analytical method. The Mine Safety and Health Administration (MSHA) routinely utilizes this LTA method to quantify the incombustible content of bulk dust samples collected from the roof, floor, and ribs of mining entries. The use of the stainless steel cassette with isokinetic inlet allowed NIOSH to adopt the LTA method for the analysis of airborne dust samples. Mixtures of known coal and limestone dust masses were prepared in the laboratory, loaded into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal dust mass measurements differed from predicted values by an average of 0.5%, 0.2%, and 0.1% for samples containing 20%, 91%, and 95% limestone dust, respectively. The ability of this method to accurately quantify the laboratory samples confirmed the validity of this method and allowed NIOSH to successfully measure the coal fraction of airborne dust samples collected in an underground coal mine. PMID:26618374

  14. Sampling and analysis method for measuring airborne coal dust mass in mixtures with limestone (rock) dust.

    PubMed

    Barone, T L; Patts, J R; Janisko, S J; Colinet, J F; Patts, L D; Beck, T W; Mischler, S E

    2016-01-01

    Airborne coal dust mass measurements in underground bituminous coal mines can be challenged by the presence of airborne limestone dust, which is an incombustible dust applied to prevent the propagation of dust explosions. To accurately measure the coal portion of this mixed airborne dust, the National Institute for Occupational Safety and Health (NIOSH) developed a sampling and analysis protocol that used a stainless steel cassette adapted with an isokinetic inlet and the low temperature ashing (LTA) analytical method. The Mine Safety and Health Administration (MSHA) routinely utilizes this LTA method to quantify the incombustible content of bulk dust samples collected from the roof, floor, and ribs of mining entries. The use of the stainless steel cassette with isokinetic inlet allowed NIOSH to adopt the LTA method for the analysis of airborne dust samples. Mixtures of known coal and limestone dust masses were prepared in the laboratory, loaded into the stainless steel cassettes, and analyzed to assess the accuracy of this method. Coal dust mass measurements differed from predicted values by an average of 0.5%, 0.2%, and 0.1% for samples containing 20%, 91%, and 95% limestone dust, respectively. The ability of this method to accurately quantify the laboratory samples confirmed the validity of this method and allowed NIOSH to successfully measure the coal fraction of airborne dust samples collected in an underground coal mine.

  15. 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

  16. Airborne volcanic plume measurements using a FTIR spectrometer, Kilauea volcano, Hawaii

    USGS Publications Warehouse

    McGee, K.A.; Gerlach, T.M.

    1998-01-01

    A prototype closed-path Fourier transform infrared spectrometer system (FTIK), operating from battery power and with a Stirling engine microcooler for detector cooling, was successfully used for airborne measurements of sulfur dioxide at Kilauea volcano. Airborne profiles of the volcanic plume emanating from the erupting Pu'u 'O'o vent on the East Rift of Kilauea revealed levels of nearly 3 ppm SO2 in the core of the plume. An emission rate of 2,160 metric tons per day of sulfur dioxide was calculated from the FTIR data, which agrees closely with simultaneous measurements by a correlation spectrometer (COSPEC). The rapid spatial sampling possible from an airborne platform distinguishes the methodology described here from previous FTIR measurements.

  17. The Multi-Center Airborne Coherent Atmospheric Wind Sensor: Recent Measurements and Future Applications

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; Cutten, Dean R.; Hardesty, R. Michael; Howell, James N.; Darby, Lisa S.; Tratt, David M.; Menzies, Robert T.

    1999-01-01

    The coherent Doppler lidar, when operated from an airborne platform, offers a unique measurement capability for study of atmospheric dynamical and physical properties. This is especially true for scientific objectives requiring measurements in optically-clear air, where other remote sensing technologies such as Doppler radar are at a disadvantage in terms of spatial resolution and coverage. Recent experience suggests airborne coherent Doppler lidar can yield unique wind measurements of--and during operation within--extreme weather phenomena. This paper presents the first airborne coherent Doppler lidar measurements of hurricane wind fields. The lidar atmospheric remote sensing groups of National Aeronautics and Space Administration (NASA) Marshall Space Flight Center, National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratory, and Jet Propulsion Laboratory jointly developed an airborne lidar system, the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS). The centerpiece of MACAWS is the lidar transmitter from the highly successful NOAA Windvan. Other field-tested lidar components have also been used, when feasible, to reduce costs and development time. The methodology for remotely sensing atmospheric wind fields with scanning coherent Doppler lidar was demonstrated in 1981; enhancements were made and the system was reflown in 1984. MACAWS has potentially greater scientific utility, compared to the original airborne scanning lidar system, owing to a factor of approx. 60 greater energy-per-pulse from the NOAA transmitter. MACAWS development was completed and the system was first flown in 1995. Following enhancements to improve performance, the system was re-flown in 1996 and 1998. The scientific motivation for MACAWS is three-fold: obtain fundamental measurements of subgrid scale (i.e., approx. 2-200 km) processes and features which may be used to improve parameterizations in hydrological, climate, and general

  18. Estimation of Aerosol Direct Radiative Effects from Satellite and In Situ Measurements

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Russell, Philip B.; Schmid, Beat; Redemann, Jens; McIntosh, Dawn

    2000-01-01

    Ames researchers have combined measurements from satellite, aircraft, and the surface to estimate the effect of airborne particles (aerosols) on the solar radiation over the North Atlantic region. These aerosols (which come from both natural and pollution sources) can reflect solar radiation, causing a cooling effect that opposes the warming caused by carbon dioxide. Recently, increased attention has been paid to aerosol effects to better understand the Earth climate system.

  19. Column CO2 Measurement From an Airborne Solid-State Double-Pulsed 2-Micron Integrated Path Differential Absorption Lidar

    NASA Technical Reports Server (NTRS)

    Singh, U. N.; Yu, J.; Petros, M.; Refaat, T. F.; Remus, R.; Fay, J.; Reithmaier, K.

    2014-01-01

    NASA LaRC is developing and integrating a double-Pulsed 2-micron direct detection IPDA lidar for CO2 column measurement from an airborne platform. The presentation will describe the development of the 2-micrometers IPDA lidar system and present the airborne measurement of column CO2 and will compare to in-situ measurement for various ground target of different reflectivity.

  20. Atmospheric Airborne Pressure Measurements Using the Oxygen A Band for the ASCENDS Mission

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Rodriguez, Mike; Stephen, Mark; Hasselbrack, William; Allan, Graham; Mao, Jiamping,; Kawa, Stephan R.; Weaver, Clark J.

    2011-01-01

    We report on airborne atmospheric pressure measurements using new fiber-based laser technology and the oxygen A-band at 765 nm. Remote measurements of atmospheric temperature and pressure are required for a number of NASA Earth science missions and specifically for the Active Sensing of CO2 Emissions Over Nights, Days, and Seasons (ASCENDS) mission. Accurate measurements of tropospheric CO2 on a global scale are very important in order to better understand its sources and sinks and to improve predictions on any future climate change. The ultimate goal of a CO2 remote sensing mission, such as ASCENDS, is to derive the CO2 concentration in the atmosphere in terms of mole fraction in unit of parts-per-million (ppmv) with regard to dry air. Therefore, both CO2 and the dry air number of molecules in the atmosphere are needed in deriving this quantity. O2 is a stable molecule and uniformly mixed in the atmosphere. Measuring the O2 absorption in the atmosphere can thus be used to infer the dry air number of molecules and then used to calculate CO2 concentration. With the knowledge of atmospheric water vapor, we can then estimate the total surface pressure needed for CO2 retrievals. Our work, funded by the ESTO IIP program, uses fiber optic technology and non-linear optics to generate 765 nm laser radiation coincident with the Oxygen A-band. Our pulsed, time gated technique uses several on- and off-line wavelengths tuned to the O2 absorption line. The choice of wavelengths allows us to measure the pressure by using two adjacent O2 absorptions in the Oxygen A-band. Our retrieval algorithm fits the O2 lineshapes and derives the pressure. Our measurements compare favorably with a local weather monitor mounted outside our laboratory and a local weather station.

  1. Atmospheric Airborne Pressure Measurements Using the Oxygen A Band for the ASCENDS Mission

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Rodriguez, Mike; Stephen, Mark; Hasselbrack, William; Allan, Graham; Mao, Jianping; Kawa, Stephen R.; Weaver, Clark J.

    2010-01-01

    We report on airborne atmospheric pressure measurements using new fiber-based laser technology and the oxygen A-band at 765 nm. Remote measurements of atmospheric temperature and pressure are required for a number of NASA Earth science missions and specifically for the Active Sensing of CO2 Emissions Over Nights, Days, and Seasons (ASCENDS) mission. Accurate measurements of tropospheric CO2 on a global scale are very important in order to better understand its sources and sinks and to improve predictions on any future climate change. The ultimate goal of a CO2 remote sensing mission, such as ASCENDS, is to derive the CO2 concentration in the atmosphere in terms of mole fraction in unit of parts-per-million (ppmv) with regard to dry air. Therefore, both CO2 and the dry air number of molecules in the atmosphere are needed in deriving this quantity. O2 is a stable molecule and uniformly mixed in the atmosphere. Measuring the O2 absorption in the atmosphere can thus be used to infer the dry air number of molecules and then used to calculate CO2 concentration. With the knowledge of atmospheric water vapor, we can then estimate the total surface pressure needed for CO2 retrievals. Our work, funded by the ESTO IIP program, uses fiber optic technology and non-linear optics to generate 765 nm laser radiation coincident with the Oxygen A-band. Our pulsed, time gated technique uses several on- and off-line wavelengths tuned to the O2 absorption line. The choice of wavelengths allows us to measure the pressure by using two adjacent O2 absorptions in the Oxygen A-band. Our retrieval algorithm fits the O2 lineshapes and derives the pressure. Our measurements compare favorably with a local weather monitor mounted outside our laboratory and a local weather station.

  2. Airborne lidar measurements of ozone and aerosols during the pacific exploratory mission-tropics A

    NASA Technical Reports Server (NTRS)

    Fenn, Marta A.; Browell, Edward V.; Grant, William B.; Butler, Carolyn F.; Kooi, Susan A.; Clayton, Marian B.; Brackett, Vincent G.; Gregory, Gerald L.

    1998-01-01

    Airborne lidar measurements of aerosol and ozone distributions from the surface to above the tropopause over the South Pacific Ocean are presented. The measurements illustrate large-scale features of the region, and are used to quantify the relative contributions of different ozone sources to the tropospheric ozone budget in this remote region.

  3. Airborne 2-Micron Double Pulsed Direct Detection IPDA Lidar for Atmospheric CO2 Measurement

    NASA Astrophysics Data System (ADS)

    Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Reithmaier, Karl; Remus, Ruben; Singh, Upendra; Johnson, Will; Boyer, Charlie; Fay, James; Johnston, Susan; Murchison, Luke

    2016-06-01

    An airborne 2-micron double-pulsed Integrated Path Differential Absorption (IPDA) lidar has been developed for atmospheric CO2 measurements. This new instrument has been flown in spring of 2014 for a total of ten flights with 27 flight hours. This IPDA lidar provides high precision measurement capability by unambiguously eliminating contamination from aerosols and clouds that can bias the results.

  4. Four-laser airborne infrared spectrometer for atmospheric trace gas measurements.

    PubMed

    Roths, J; Zenker, T; Parchatka, U; Wienhold, F G; Harris, G W

    1996-12-20

    We describe the four-laser airborne infrared (FLAIR) instrument, a tunable diode laser absorption spectrometer designed for simultaneous high-sensitivity in situ measurements of four atmospheric trace gases in the troposphere. The FLAIR spectrometer was employed during the large-scale airborne research campaign on tropospheric ozone (TROPOZ II) in 1991 and was used to measure CO, H(2) O(2), HCHO, and NO(2) in the free troposphere where detection limits below 100 parts in 10(12) by volume were achieved.

  5. Development of Airborne Eddy-Correlation Flux Measurement Capabilities for Reactive Oxides of Nitrogen

    NASA Technical Reports Server (NTRS)

    Sandholm, Scott

    1998-01-01

    This report addresses the Tropospheric Trace Gas and Airborne Measurement Group (TTGAMG) endeavors to continue to push the evolution of the Georgia Institute of Technology's Airborne Laser Induced Fluorescence Experiment (GITALIFE) into a sensor capable of making airborne eddy correlation measurements of nitrogen oxides. It will mainly address the TTGAMG successes and failures as well as its participation in the summer 1998 Wallops Island test flights on board the P3-B. Due to the restructuring and reorganization of the TTGAMG since the original funding of this grant, some of the objectives and the deliverables can not be achieved as proposed in the original funding of this grant. Most of these changes have been driven by the passing away of John Bradshaw, the original principal investigator.

  6. How Cities Breathe: Ground-Referenced, Airborne Hyperspectral Imaging Precursor Measurements To Space-Based Monitoring

    NASA Technical Reports Server (NTRS)

    Leifer, Ira; Tratt, David; Quattrochi, Dale; Bovensmann, Heinrich; Gerilowski, Konstantin; Buchwitz, Michael; Burrows, John

    2013-01-01

    Methane's (CH4) large global warming potential (Shindell et al., 2012) and likely increasing future emissions due to global warming feedbacks emphasize its importance to anthropogenic greenhouse warming (IPCC, 2007). Furthermore, CH4 regulation has far greater near-term climate change mitigation potential versus carbon dioxide CO2, the other major anthropogenic Greenhouse Gas (GHG) (Shindell et al., 2009). Uncertainties in CH4 budgets arise from the poor state of knowledge of CH4 sources - in part from a lack of sufficiently accurate assessments of the temporal and spatial emissions and controlling factors of highly variable anthropogenic and natural CH4 surface fluxes (IPCC, 2007) and the lack of global-scale (satellite) data at sufficiently high spatial resolution to resolve sources. Many important methane (and other trace gases) sources arise from urban and mega-urban landscapes where anthropogenic activities are centered - most of humanity lives in urban areas. Studying these complex landscape tapestries is challenged by a wide and varied range of activities at small spatial scale, and difficulty in obtaining up-to-date landuse data in the developed world - a key desire of policy makers towards development of effective regulations. In the developing world, challenges are multiplied with additional political access challenges. As high spatial resolution satellite and airborne data has become available, activity mapping applications have blossomed - i.e., Google maps; however, tap a minute fraction of remote sensing capabilities due to limited (three band) spectral information. Next generation approaches that incorporate high spatial resolution hyperspectral and ultraspectral data will allow detangling of the highly heterogeneous usage megacity patterns by providing diagnostic identification of chemical composition from solids (refs) to gases (refs). To properly enable these next generation technologies for megacity include atmospheric radiative transfer modeling

  7. Method and Apparatus for Measuring Radiation Quantities

    DOEpatents

    Roberts, N O

    1955-01-25

    This patent application describes a compact dosimeter for measuring X-ray and gamma radiation by the use of solutions which undergo a visible color change upon exposure to a predetermined quantity of radiation.

  8. An Empirical Function for Bidirectional Reflectance Characterization for Smoke Aerosols Using Multi-angular Airborne Measurements

    NASA Astrophysics Data System (ADS)

    Poudyal, R.; Singh, M. K.; Gatebe, C. K.; Gautam, R.; Varnai, T.

    2015-12-01

    Using airborne Cloud Absorption Radiometer (CAR) reflectance measurements of smoke, an empirical relationship between reflectances measured at different sun-satellite geometry is established, in this study. It is observed that reflectance of smoke aerosol at any viewing zenith angle can be computed using a linear combination of reflectance at two viewing zenith angles. One of them should be less than 30° and other must be greater than 60°. We found that the parameters of the linear combination computation follow a third order polynomial function of the viewing geometry. Similar relationships were also established for different relative azimuth angles. Reflectance at any azimuth angle can be written as a linear combination of measurements at two different azimuth angles. One must be in the forward scattering direction and the other in backward scattering, with both close to the principal plane. These relationships allowed us to create an Angular Distribution Model (ADM) for smoke, which can estimate reflectances in any direction based on measurements taken in four view directions. The model was tested by calculating the ADM parameters using CAR data from the SCAR-B campaign, and applying these parameters to different smoke cases at three spectral channels (340nm, 380nm and 470nm). We also tested our modelled smoke ADM formulas with Absorbing Aerosol Index (AAI) directly computed from the CAR data, based on 340nm and 380nm, which is probably the first study to analyze the complete multi-angular distribution of AAI for smoke aerosols. The RMSE (and mean error) of predicted reflectance for SCAR-B and ARCTAS smoke ADMs were found to be 0.002 (1.5%) and 0.047 (6%), respectively. The accuracy of the ADM formulation is also tested through radiative transfer simulations for a wide variety of situations (varying smoke loading, underlying surface types, etc.).

  9. Seagrass biomass and productivity in the Florida Keys, USA: ground-level and airborne measurements

    NASA Astrophysics Data System (ADS)

    Yarbro, L.; Carlson, P. R., Jr.; McHan, C.; Carlson, D. F.; Hu, C.; Danielson, T.; Durnan, B.; English, D. C.; Muller-Karger, F. E.; Yates, K. K.; Herwitz, S.; Merrill, J.; Mewes, T.

    2013-12-01

    Seagrass communities serve as essential habitat for fish and shellfish, and recent research indicates that they can play a significant role in reducing ocean acidification. As part of a collaborative project funded by the NASA ROSES program and administered by the NASA UAV Collaborative, we collected hyperspectral imagery of seagrass beds and measured productivity of Thalassia testudinum at Sugarloaf Key, Florida, in May 2012, October 2012, and May 2013. Our primary goal was to evaluate the utility of hyperspectral sensors, in general, and UAV platforms, in specific, to measure seagrass health and productivity. Airborne measurements using the AISA Eagle hyperspectral imaging system were carried out simultaneously with ground measurements of Thalassia fluorescence, oxygen metabolism, growth, and biomass, as well as remote sensing reflectance and several in situ optical properties. Water depths at the study site ranged from less than 1 m to 5 m. Phytoplankton chlorophyll-a concentrations (0.09-0.72 ug l-1), ag(440) (0-0.02 m-1), and turbidity (0.12-4.1 ntu) were relatively low for all three deployments, facilitating the collection of excellent imagery and application of water-column radiative-transfer corrections. Aboveground Thalassia and macroalgal biomass, at 18 sites in the study area, ranged from 210 to 690 and 11 to 590 gDW m-2, respectively. One-sided green leaf area index of Thalassia ranged from 0.7 to 3.0. Preliminary findings show that the sensitivity of relationships between seagrass productivity and biomass parameters and remotely-sensed habitat spectra is reduced with increasing water depth and, even in shallow water, is complicated by epiphytic algae and sediment coverage of leaf surfaces.

  10. High Energy 2-Micron Solid-State Laser Transmitter for NASA's Airborne CO2 Measurements

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Bai, Yingxin

    2012-01-01

    A 2-micron pulsed, Integrated Path Differential Absorption (IPDA) lidar instrument for ground and airborne atmospheric CO2 concentration measurements via direct detection method is being developed at NASA Langley Research Center. This instrument will provide an alternate approach to measure atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capability by having high signal-to-noise level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement.

  11. Wave-measurement capabilities of the surface contour radar and the airborne oceanographic lidar

    NASA Technical Reports Server (NTRS)

    Walsh, Edward J.; Hancock, David W., III; Hines, Donald E.; Swift, Robert N.; Scott, John F.

    1987-01-01

    The 36-gigahertz surface contour radar and the airborne oceanographic lidar were used in the SIR-B underflight mission off the coast of Chile in October 1984. The two systems and some of their wave-measurement capabilities are described. The surface contour radar can determine the directional wave spectrum and eliminate the 180-degree ambiguity in wave propagation direction that is inherent in some other techniques such as stereophotography and the radar ocean wave spectrometer. The Airborne Oceanographic Lidar can acquire profile data on the waves and produce a spectrum that is close to the nondirectional ocean-wave spectrum for ground tracks parallel to the wave propagation direction.

  12. 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).

  13. Experimental feasibility of the airborne measurement of absolute oil fluorescence spectral conversion efficiency

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1983-01-01

    Airborne lidar oil spill experiments carried out to determine the practicability of the AOFSCE (absolute oil fluorescence spectral conversion efficiency) computational model are described. The results reveal that the model is suitable over a considerable range of oil film thicknesses provided the fluorescence efficiency of the oil does not approach the minimum detection sensitivity limitations of the lidar system. Separate airborne lidar experiments to demonstrate measurement of the water column Raman conversion efficiency are also conducted to ascertain the ultimate feasibility of converting such relative oil fluorescence to absolute values. Whereas the AOFSCE model is seen as highly promising, further airborne water column Raman conversion efficiency experiments with improved temporal or depth-resolved waveform calibration and software deconvolution techniques are thought necessary for a final determination of suitability.

  14. 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.

  15. Lidar Measurements of Aerosol and Ozone Distributions During the 1992 Airborne Arctic Stratospheric Expedition

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Butler, C. F.; Fenn, M. A.; Grant, W. B.; Carter, A. F.

    1992-01-01

    The LaRC airborne lidar system was operated from the ARC DC-8 aircraft during the 1992 Airborne Arctic Stratospheric Expedition (ASEE-2) to investigate the distribution of stratospheric aerosols and O3 across the Arctic vortex from Jan. to Mar. 1992. Monthly flights were made across the Arctic vortex from Anchorage, Alaska, to Stavanger, Norway, and then back to Bangor, Maine, and additional round-trip flights north into the vortex were made each month from either Stavanger or Bangor depending on the location of the vortex that month. The airborne lidar system uses the differential absorption lidar (DIAL) technique at laser wavelengths of 301.5 and 310.8 nm to measure O3 profiles above the DC-8 over the 12-25 km altitude range. Lidar measurements of aerosol backscatter and depolarization profiles over the 12-30 km altitude range are made simultaneously with the O3 measurements using infrared (IR) and visible (VIS) laser wavelengths of 603 and 1064 nm, respectively. The measurements of Pinatubo aerosols, polar stratospheric clouds, and O3 made with the airborne DIAL system during the AASE-2 expedition and to chemical and dynamical process that contribute to O3 depletion in the wintertime Arctic stratosphere.

  16. Airborne Measurements in Support of the NASA Atmospheric Carbon and Transport - America (ACT-America) Mission

    NASA Technical Reports Server (NTRS)

    Meadows, Byron; Davis, Ken; Barrick, John; Browell, Edward; Chen, Gao; Dobler, Jeremy; Fried, Alan; Lauvaux, Thomas; Lin, Bing; McGill, Matt; Miles, Natasha; Nehrir, Amin; Obland, Michael; O'Dell, Chris; Sweeney, Colm; Yang, Melissa

    2015-01-01

    NASA announced the research opportunity Earth Venture Suborbital -2 (EVS-2) mission in support of the NASA's science strategic goals and objectives in 2013. Penn State University, NASA Langley Research Center (LaRC), and other academic institutions, government agencies, and industrial companies together formulated and proposed the Atmospheric Carbon and Transport -America (ACT -America) suborbital mission, which was subsequently selected for implementation. The airborne measurements that are part of ACT-America will provide a unique set of remote and in-situ measurements of CO2 over North America at spatial and temporal scales not previously available to the science community and this will greatly enhance our understanding of the carbon cycle. ACT -America will consist of five airborne campaigns, covering all four seasons, to measure regional atmospheric carbon distributions and to evaluate the accuracy of atmospheric transport models used to assess carbon sinks and sources under fair and stormy weather conditions. This coordinated mission will measure atmospheric carbon in the three most important regions of the continental US carbon balance: Northeast, Midwest, and South. Data will be collected using 2 airborne platforms (NASA Wallops' C-130 and NASA Langley's B-200) with both in-situ and lidar instruments, along with instrumented ground towers and under flights of the Orbiting Carbon Observatory (OCO-2) satellite. This presentation provides an overview of the ACT-America instruments, with particular emphasis on the airborne CO2and backscatter lidars, and the, rationale, approach, and anticipated results from this mission.

  17. Airborne measurements in the longwave infrared using an imaging hyperspectral sensor

    NASA Astrophysics Data System (ADS)

    Allard, Jean-Pierre; Chamberland, Martin; Farley, Vincent; Marcotte, Frédérick; Rolland, Matthias; Vallières, Alexandre; Villemaire, André

    2008-07-01

    Emerging applications in Defense and Security require sensors with state-of-the-art sensitivity and capabilities. Among these sensors, the imaging spectrometer is an instrument yielding a large amount of rich information about the measured scene. Standoff detection, identification and quantification of chemicals in the gaseous state is one important application. Analysis of the surface emissivity as a means to classify ground properties and usage is another one. Imaging spectrometers have unmatched capabilities to meet the requirements of these applications. Telops has developed the FIRST, a LWIR hyperspectral imager. The FIRST is based on the Fourier Transform technology yielding high spectral resolution and enabling high accuracy radiometric calibration. The FIRST, a man portable sensor, provides datacubes of up to 320×256 pixels at 0.35mrad spatial resolution over the 8-12 μm spectral range at spectral resolutions of up to 0.25cm-1. The FIRST has been used in several field campaigns, including the demonstration of standoff chemical agent detection [http://dx.doi.org/10.1117/12.788027.1]. More recently, an airborne system integrating the FIRST has been developed to provide airborne hyperspectral measurement capabilities. The airborne system and its capabilities are presented in this paper. The FIRST sensor modularity enables operation in various configurations such as tripod-mounted and airborne. In the airborne configuration, the FIRST can be operated in push-broom mode, or in staring mode with image motion compensation. This paper focuses on the airborne operation of the FIRST sensor.

  18. Southern Hemispheric nitrous oxide measurements obtained during 1987 airborne Antarctic ozone experiment

    NASA Technical Reports Server (NTRS)

    Podolske, J. R.; Loewenstein, M.; Strahan, S. E.; Chan, K. Roland

    1988-01-01

    The chemical lifetime of N2O is about 150 years, which makes it an excellent dynamical tracer of air motion on the time scale of the ozone depletion event. For these reasons it was chosen to help test whether dynamical theories of ozone loss over Antarctica were plausible, particularly the theory that upwelling ozone-poor air from the troposphere was replacing ozone-rich stratospheric air. The N2O measurements were made with the Airborne Tunable Laser Absorption Spectrometer (ATLAS) aboard the NASA ER-2 aircraft. The detection technique involves measuring the diffential absorption of the IR laser radiation as it is rapidly scanned over an N2O absorption feature. For the AAOE mission, the instrument was capable of making measurements with a 1 ppb sensitivity, 1 second response time, over an altitude range of 10 to 20 kilometers. The AAOE mission consisted of a series of 12 flights from Punta Arenas (53S) into the polar vortex (approximately 72S) at which time a vertical profile from 65 to 45 km and back was performed. Comparison of the observed profiles inside the vortex with N2O profiles obtained by balloon flights during the austral summer showed that an overall subsidence had occurred during the winter of about 5 to 6 km. Also, over the course of the mission (mid-August to late September), no trend in the N2O vertical profile, either upward or downward, was discernible, eliminating the possibility that upwelling was the cause of the observed ozone decrease.

  19. Magnetic Approaches to Measuring and Mitigating Airborne Particulate Pollution

    NASA Astrophysics Data System (ADS)

    Maher, B.

    2014-12-01

    Human exposure to airborne particulate matter (PM) generates adverse human health impacts at all life stages from the embryonic to the terminal, including damage to respiratory and cardiovascular health, and neurodevelopment and cognitive function. Detailed understanding of the causal links between PM exposure and specific health impacts, and possible means to reduce PM exposure require knowledge of PM concentrations, compositions and sources at the fine-scale; i.e. beyond the current resolution of spatially-sparse conventional PM monitoring, non-unique elemental analyses, or poorly-validated PM modelling. Magnetically-ordered iron oxide minerals appear to be a ubiquitous component of urban PM. These minerals derive partly from the presence of iron impurities in fuels, which form, upon combustion, a non-volatile residue, often dominated by magnetite, within glassy, spherical condensates. Iron-rich, magnetic PM also arises from abrasion from vehicle components, including disk brakes, and road dust. The ubiquity and diversity of these magnetic PM phases, and the speed and sensitivity of magnetic analyses (down to trace concentrations), makes possible rapid, cost-effective magnetic characterization and quantification of PM, a field of study which has developed rapidly across the globe over the last 2 decades. Magnetic studies of actively-sampled PM, on filters, and passively-sampled PM, on tree leaves and other depositional surfaces, can be used to: monitor and map at high spatial resolution ambient PM concentrations; address the controversial issue of the efficacy of PM capture by vegetation; and add a new, discriminatory dimension to PM source apportionment.

  20. Real-time remote detection and measurement for airborne imaging spectroscopy: a case study with methane

    NASA Astrophysics Data System (ADS)

    Thompson, D. R.; Leifer, I.; Bovensmann, H.; Eastwood, M.; Fladeland, M.; Frankenberg, C.; Gerilowski, K.; Green, R. O.; Kratwurst, S.; Krings, T.; Luna, B.; Thorpe, A. K.

    2015-10-01

    Localized anthropogenic sources of atmospheric CH4 are highly uncertain and temporally variable. Airborne remote measurement is an effective method to detect and quantify these emissions. In a campaign context, the science yield can be dramatically increased by real-time retrievals that allow operators to coordinate multiple measurements of the most active areas. This can improve science outcomes for both single- and multiple-platform missions. We describe a case study of the NASA/ESA CO2 and MEthane eXperiment (COMEX) campaign in California during June and August/September 2014. COMEX was a multi-platform campaign to measure CH4 plumes released from anthropogenic sources including oil and gas infrastructure. We discuss principles for real-time spectral signature detection and measurement, and report performance on the NASA Next Generation Airborne Visible Infrared Spectrometer (AVIRIS-NG). AVIRIS-NG successfully detected CH4 plumes in real-time at Gb s-1 data rates, characterizing fugitive releases in concert with other in situ and remote instruments. The teams used these real-time CH4 detections to coordinate measurements across multiple platforms, including airborne in situ, airborne non-imaging remote sensing, and ground-based in situ instruments. To our knowledge this is the first reported use of real-time trace-gas signature detection in an airborne science campaign, and presages many future applications. Post-analysis demonstrates matched filter methods providing noise-equivalent (1σ) detection sensitivity for 1.0 % CH4 column enhancements equal to 141 ppm m.

  1. Carbon monoxide total column retrievals by use of the measurements of pollution in the troposphere airborne test radiometer.

    PubMed

    Niu, Jianguo; Deeter, Merritt N; Gille, John C; Edwards, David P; Ziskin, Daniel C; Francis, Gene L; Hills, Alan J; Smith, Mark W

    2004-08-20

    The Measurements of Pollution in the Troposphere (MOPITT) Airborne Test Radiometer (MATR) uses gas correlation filter radiometry from high-altitude aircraft to measure tropospheric carbon monoxide. This radiometer is used in support of the ongoing validation campaign for the MOPITT instrument aboard the Earth Observation System Terra satellite. A recent study of MATR CO retrievals that used data from the autumn of 2001 in the western United States is presented. Retrievals of the CO total column were performed and compared to in situ sampling with less than 10% retrieval error. Effects that influence retrieval, such as instrument sensitivity, retrieval sensitivity, and the bias between observations and the radiative transfer model, are discussed. Comparisons of MATR and MOPITT retrievals show promising consistency. A preliminary interpretation of MATR results is also presented.

  2. Airborne DIAL and ground-based Raman lidar measurements of water vapor over the Southern Great Plains

    NASA Astrophysics Data System (ADS)

    Ferrare, Richard A.; Browell, Edward V.; Ismail, Syed; Kooi, Susan; Brackett, Vince G.; Clayton, Marian; Notari, Anthony; Butler, Carolyn F.; Barrick, John; Diskin, Glenn; Lesht, Barry; Schmidlin, Frank J.; Turner, Dave; Whiteman, David; Miloshevich, Larry

    2003-12-01

    Measurements of water vapor profiles over the Southern Great Plains acquired by two different lidars are presented. NASA's airborne DIAL Lidar Atmospheric Sensing Experiment (LASE) system measured water vapor, aerosol, and cloud profiles during the ARM/FIRE Water Vapor Experiment (AFWEX) in November-December 2000 and during the International H2O Project (IHOP) in May-June 2002. LASE measurements acquired during AFWEX are used to characterize upper troposphere water vapor measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors. LASE measurements acquired during IHOP are being used to better understand the influence water vapor variability on the initiation of deep convection and to improve the quantification and prediction of precipitation associated with these storms. The automated Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Raman Lidar (CARL) has been routinely measuring profiles of water vapor mixing ratio, relative humidity, aerosol extinction, aerosol backscattering, and aerosol and cloud depolarization during both daytime and nighttime operations. Aerosol and water vapor profiles acquired since March 1998 are used to investigate the seasonal variability of the vertical distributions of water vapor and aerosols.

  3. 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

  4. 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

  5. Simulations of an airborne laser absorption spectrometer for atmospheric CO2 measurements

    NASA Astrophysics Data System (ADS)

    Lin, B.; Ismail, S.; Harrison, F. W.; Browell, E. V.; Dobler, J. T.; Refaat, T.; Kooi, S. A.

    2012-12-01

    Atmospheric column amount of carbon dioxide (CO2), a major greenhouse gas of the atmosphere, has significantly increased from a preindustrial value of about 280 parts per million (ppm) to more than 390 ppm at present. Our knowledge about the spatiotemporal change and variability of the greenhouse gas, however, is limited. Thus, a near-term space mission of the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) is crucial to increase our understanding of global sources and sinks of CO2. Currently, NASA Langley Research Center (LaRC) and ITT Exelis are jointly developing and testing an airborne laser absorption spectrometer (LAS) as a prototype instrument for the mission. To assess the space capability of accurate atmospheric CO2 measurements, accurate modeling of the instrument and practical evaluation of space applications are the keys for the success of the ASCENDS mission. This study discusses the simulations of the performance of the airborne instrument and its CO2 measurements. The LAS is a multi-wavelength spectrometer operating on a 1.57 um CO2 absorption line. The Intensity-Modulated Continuous-Wave (IM-CW) approach is implemented in the instrument. To reach accurate CO2 measurements, transmitted signals are monitored internally as reference channels. A model of this kind of instrument includes all major components of the spectrometer, such as modulation generator, fiber amplifier, telescope, detector, transimpedance amplifier, matched filter, and other signal processors. The characteristics of these components are based on actual laboratory tests, product specifications, and general understanding of the functionality of the components. For simulations of atmospheric CO2 measurements, environmental conditions related to surface reflection, atmospheric CO2 and H2O profiles, thin clouds, and aerosol layers, are introduced into the model. Furthermore, all major noise sources such as those from detectors, background radiation, speckle, and

  6. Airborne 2-Micron Double-Pulsed Integrated Path Differential Absorption Lidar for Column CO2 Measurement

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer F.; Remus, Ruben G.; Fay, James J.; Reithmaier, Karl

    2014-01-01

    Double-pulse 2-micron lasers have been demonstrated with energy as high as 600 millijouls and up to 10 Hz repetition rate. The two laser pulses are separated by 200 microseconds and can be tuned and locked separately. Applying double-pulse laser in DIAL system enhances the CO2 measurement capability by increasing the overlap of the sampled volume between the on-line and off-line. To avoid detection complicity, integrated path differential absorption (IPDA) lidar provides higher signal-to-noise ratio measurement compared to conventional range-resolved DIAL. Rather than weak atmospheric scattering returns, IPDA rely on the much stronger hard target returns that is best suited for airborne platforms. In addition, the IPDA technique measures the total integrated column content from the instrument to the hard target but with weighting that can be tuned by the transmitter. Therefore, the transmitter could be tuned to weight the column measurement to the surface for optimum CO2 interaction studies or up to the free troposphere for optimum transport studies. Currently, NASA LaRC is developing and integrating a double-Pulsed 2-micron direct detection IPDA lidar for CO2 column measurement from an airborne platform. The presentation will describe the development of the 2-micron IPDA lidar system and present the airborne measurement of column CO2 and will compare to in-situ measurement for various ground target of different reflectivity.

  7. Airborne 2-micron double-pulsed integrated path differential absorption lidar for column CO2 measurement

    NASA Astrophysics Data System (ADS)

    Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer F.; Remus, Ruben G.; Fay, James J.; Reithmaier, Karl

    2014-10-01

    Double-pulse 2-micron lasers have been demonstrated with energy as high as 600 mJ and up to 10 Hz repetition rate. The two laser pulses are separated by 200 µs and can be tuned and locked separately. Applying double-pulse laser in DIAL system enhances the CO2 measurement capability by increasing the overlap of the sampled volume between the on-line and off-line. To avoid detection complicity, integrated path differential absorption (IPDA) lidar provides higher signal-to-noise ratio measurement compared to conventional range-resolved DIAL. Rather than weak atmospheric scattering returns, IPDA rely on the much stronger hard target returns that is best suited for airborne platforms. In addition, the IPDA technique measures the total integrated column content from the instrument to the hard target but with weighting that can be tuned by the transmitter. Therefore, the transmitter could be tuned to weight the column measurement to the surface for optimum CO2 interaction studies or up to the free troposphere for optimum transport studies. Currently, NASA LaRC is developing and integrating a double-Pulsed 2-µm direct detection IPDA lidar for CO2 column measurement from an airborne platform. The presentation will describe the development of the 2-μm IPDA lidar system and present the airborne measurement of column CO2 and will compare to in-situ measurement for various ground target of different reflectivity.

  8. Assessment of water pollution by airborne measurement of chlorophyll

    NASA Technical Reports Server (NTRS)

    Arvesen, J. C.; Weaver, E. C.; Millard, J. P.

    1972-01-01

    Remote measurement of chlorophyll concentrations to determine extent of water pollution is discussed. Construction and operation of radiometer to provide measurement capability are explained. Diagram of equipment is provided.

  9. Device and method for accurately measuring concentrations of airborne transuranic isotopes

    DOEpatents

    McIsaac, C.V.; Killian, E.W.; Grafwallner, E.G.; Kynaston, R.L.; Johnson, L.O.; Randolph, P.D.

    1996-09-03

    An alpha continuous air monitor (CAM) with two silicon alpha detectors and three sample collection filters is described. This alpha CAM design provides continuous sampling and also measures the cumulative transuranic (TRU), i.e., plutonium and americium, activity on the filter, and thus provides a more accurate measurement of airborne TRU concentrations than can be accomplished using a single fixed sample collection filter and a single silicon alpha detector. 7 figs.

  10. Device and method for accurately measuring concentrations of airborne transuranic isotopes

    DOEpatents

    McIsaac, Charles V.; Killian, E. Wayne; Grafwallner, Ervin G.; Kynaston, Ronnie L.; Johnson, Larry O.; Randolph, Peter D.

    1996-01-01

    An alpha continuous air monitor (CAM) with two silicon alpha detectors and three sample collection filters is described. This alpha CAM design provides continuous sampling and also measures the cumulative transuranic (TRU), i.e., plutonium and americium, activity on the filter, and thus provides a more accurate measurement of airborne TRU concentrations than can be accomplished using a single fixed sample collection filter and a single silicon alpha detector.

  11. Radiation dose measurements in coronary CT angiography

    PubMed Central

    Sabarudin, Akmal; Sun, Zhonghua

    2013-01-01

    Coronary computed tomography (CT) angiography is associated with high radiation dose and this has raised serious concerns in the literature. Awareness of various parameters for dose estimates and measurements of coronary CT angiography plays an important role in increasing our understanding of the radiation exposure to patients, thus, contributing to the implementation of dose-saving strategies. This article provides an overview of the radiation dose quantity and its measurement during coronary CT angiography procedures. PMID:24392190

  12. Comparison between carbon monoxide measurements from spaceborne and airborne platforms

    NASA Technical Reports Server (NTRS)

    Connors, V. S.; Cahoon, D. R.; Reichle, H. G., Jr.; Scheel, H. E.

    1991-01-01

    The measurements of air pollution from satellites (MAPS) experiment measured the distribution of middle tropospheric carbon monoxide (CO) from the Space Shuttle during October 1984. A critical area of the experiment is the assessment of experimental error of the MAPS data. This error is determined by the comparison between the space-based CO data and concurrent, direct CO measurements taken aboard aircraft. Because of the variability in the CO measurements near land sources, a strategy for comparing the tropospheric CO measurements over the remote oceans is presented.

  13. Method for radiation detection and measurement

    DOEpatents

    Miller, S.D.

    1993-12-21

    Dose of radiation to which a body of crystalline material has been exposed is measured by exposing the body to optical radiation at a first wavelength, which is greater than about 540 nm, and measuring optical energy emitted from the body by luminescence at a second wavelength, which is longer than the first wavelength. 9 figures.

  14. Method for radiation detection and measurement

    DOEpatents

    Miller, Steven D.

    1993-01-01

    Dose of radiation to which a body of crystalline material has been exposed is measured by exposing the body to optical radiation at a first wavelength, which is greater than about 540 nm, and measuring optical energy emitted from the body by luminescence at a second wavelength, which is longer than the first wavelength.

  15. Airborne Sunphotometry in Support of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment, 2001

    NASA Astrophysics Data System (ADS)

    Redemann, J.; Schmid, B.; Livingston, J. M.; Russell, P. B.; Eilers, J. A.; Hobbs, P. V.; Kahn, R.; Smith, W. L.

    2001-12-01

    As part of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment, July 10 - August 2, 2001, the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was operated successfully aboard the University of Washington CV-580 during 10 research flights, totaling 45.09 flight hours. The CLAMS campaign was a clear sky, shortwave (SW) closure campaign sponsored by CERES, MISR, MODIS-Atmospheres, and the NASA/GEWEX Global Aerosol Climatology Project (GACP), and entailed measurements from the Chesapeake Lighthouse research platform, several land sites, 6 research aircraft and the TERRA satellite. Among the CLAMS research goals were the validation of satellite-based retrievals of aerosol properties, vertical profiles of radiative fluxes, temperature and water vapor. AATS-14 measures the direct solar beam transmission at 14 discrete wavelengths (354-1558 nm), yielding aerosol optical depth (AOD) spectra, columnar water vapor and columnar ozone. Differentiation of AOD (CWV) with respect to altitude in favorable flight patterns, allows the derivation of aerosol extinction (water vapor density). During coordinated flights of the UW CV-580, AATS-14 measured full column aerosol optical depth spectra at exact TERRA overpass time on at least 7 occasions. For five of these opportunities, AOD at 499nm was at or below 0.1. During TERRA overpass time on July 17, 2001, AATS-14 measured the highest AOD encountered during the entire experiment (ca. 0.48 at 499nm), including a horizontal gradient in AOD of more than 0.1 over a horizontal distance of ca. 80 kilometers. In this paper, we will show first sunphotometer-derived results regarding the spatial variation of AOD and CWV during TERRA overpass time at key locations for the CLAMS experiment. Preliminary comparison studies between our AOD/aerosol extinction data and results from (i) extinction products derived using in situ measurements aboard the UW CV-580 and (ii) AOD retrievals using the Multi

  16. Noncontact Measurement of Humidity and Temperature Using Airborne Ultrasound

    NASA Astrophysics Data System (ADS)

    Akihiko Kon,; Koichi Mizutani,; Naoto Wakatsuki,

    2010-04-01

    We describe a noncontact method for measuring humidity and dry-bulb temperature. Conventional humidity sensors are single-point measurement devices, so that a noncontact method for measuring the relative humidity is required. Ultrasonic temperature sensors are noncontact measurement sensors. Because water vapor in the air increases sound velocity, conventional ultrasonic temperature sensors measure virtual temperature, which is higher than dry-bulb temperature. We performed experiments using an ultrasonic delay line, an atmospheric pressure sensor, and either a thermometer or a relative humidity sensor to confirm the validity of our measurement method at relative humidities of 30, 50, 75, and 100% and at temperatures of 283.15, 293.15, 308.15, and 323.15 K. The results show that the proposed method measures relative humidity with an error rate of less than 16.4% and dry-bulb temperature with an error of less than 0.7 K. Adaptations of the measurement method for use in air-conditioning control systems are discussed.

  17. Radiation: Physical Characterization and Environmental Measurements

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session WP4, the discussion focuses on the following topics: Production of Neutrons from Interactions of GCR-Like Particles; Solar Particle Event Dose Distributions, Parameterization of Dose-Time Profiles; Assessment of Nuclear Events in the Body Produced by Neutrons and High-Energy Charged Particles; Ground-Based Simulations of Cosmic Ray Heavy Ion Interactions in Spacecraft and Planetary Habitat Shielding Materials; Radiation Measurements in Space Missions; Radiation Measurements in Civil Aircraft; Analysis of the Pre-Flight and Post-Flight Calibration Procedures Performed on the Liulin Space Radiation Dosimeter; and Radiation Environment Monitoring for Astronauts.

  18. Pulsed Lidar Measurements of Atmospheric CO2 Column Concentration in the ASCENDS 2014 Airborne Campaign

    NASA Astrophysics Data System (ADS)

    Abshire, J. B.; Ramanathan, A. K.; Mao, J.; Riris, H.; Allan, G. R.; Hasselbrack, W. E.; Chen, J. R.

    2015-12-01

    We report progress in demonstrating a pulsed, wavelength-resolved IPDA lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission. The CO2 lidar flies on NASA's DC-8 aircraft and measures the atmospheric backscatter profiles and shape of the 1572.33 nm absorption line by using 30 wavelength samples distributed across the lube. Our post-flight analysis estimates the lidar range and pulse energies at each wavelength 10 times per second. The retrievals solve for the optimum CO2 absorption line shape and the column average CO2 concentrations using radiative transfer calculations based on HITRAN, the aircraft altitude, range to the scattering surface, and the atmospheric conditions. We compare these to CO2 concentrations sampled by in-situ sensors on the aircraft. The number of wavelength samples can be reduced in the retrievals. During the ASCENDS airborne campaign in 2013 two flights were made in February over snow in the Rocky Mountains and the Central Plains allowing measurement of snow-covered surface reflectivity. Several improvements were made to the lidar for the 2014 campaign. These included using a new step-locked laser diode source, and incorporating a new HgCdTe APD detector and analog digitizer into the lidar receiver. Testing showed this detector had higher sensitivity, analog response, and a more linear dynamic range than the PMT detector used previously. In 2014 flights were made in late August and early September over the California Central Valley, the redwood forests along the California coast, two desert areas in Nevada and California, and two flights above growing agriculture in Iowa. Two flights were also made under OCO-2 satellite ground tracks. Analyses show the retrievals of lidar range and CO2 column absorption, and mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, and through thin clouds and aerosol scattering. The lidar measurements clearly

  19. Soil moisture estimates from the SMOS Validation Rehearsal Campaign in Valencia using EMIRAD airborne measurements

    NASA Astrophysics Data System (ADS)

    Saleh Contell, K.; López-Baeza, E.; Antolín, C.; Millán, C.; Cano, A.; Wigneron, J. P.; Balling, J.; Schmidl, S. S.; Skou, N.; Kerr, Y. H.; Richaume, P.; Juglea, S.; Delwart, S.; Bouzinac, C.; Wursteisen, P.

    2009-04-01

    The European Space Agency conducted a series of flights in 2008 over the main SMOS Validation sites in Europe, amongst them at the Valencia site. The scope of these campaigns was to help in the preparation of operational soil moisture outputs to be generated by the validation teams during the SMOS commissioning phase and beyond. For that purpose, several activities were scheduled at the Valencia site as part of the SMOS Validation Rehearsal campaign. These included: i) Airborne measurements at L-band to improve the parameterisation of the microwave model L-MEB (L-band Microwave Emssion model of the Biosphere) in the area, in order to improve the match between measured brightness temperatures by SMOS, and simulations using ground-truth soil moisture. ii) Intensive soil moisture sampling in a 10 km x 10 km area to support both current studies on soil moisture spatialisation based on SVAT modelling, and the definition of homogeneous land units for the future characterisation of soil moisture at the scale of a SMOS pixel (~ 50 km). The Valencia Site is located in SE Spain, about 80 km inland to the west of Valencia. Within the Valencia validation site, an area of 10 km x 10 km was selected for the experiment. The land use in this area is dominated by vineyards and bare soil (>70%), and orchards (~18 %). Flights over this area were conducted on four different days between April 22nd and May 2nd 2008. During that period, soil moisture near the surface (0-6 cm) slowly decreased with the last rainfall having occurred on April 20. Radiometric measurements were acquired by EMIRAD (L-band, 1.4 GHz) onboard the Skyvan aircraft. The flight plan, repeated across the four days, included 4 parallel lines crossing the 10 km x 10 km area at ~2300 m above the ground level. One diagonal flight was also performed at ~900 m above the ground level on each day. EMIRAD measured the L-band radiation emitted by the surface using two horns, one close to nadir, and the other one at 43 deg

  20. 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.

  1. Radiative temperature measurements at Kupaianaha lava lake, Kilauea Volcano, Hawaii

    NASA Technical Reports Server (NTRS)

    Flynn, Luke P.; Mouginis-Mark, Peter J.; Gradie, Jonathan C.; Lucey, Paul G.

    1993-01-01

    The radiative temperature of the surface of Kupaianaha lava lake is computed using field spectroradiometer data. Observations were made during periods of active overturning. The lake surface exhibits three stages of activity. Magma fountaining and overturning events characterize stage 1, which exhibits the hottest crustal temperatures and the largest fractional hot areas. Rifting events between plates of crust mark stage 2; crustal temperatures in this stage are between 100 C and 340 C, and fractional hot areas are at least an order of magnitude smaller than those in stage 1. Stage 3 is characterized by quiescent periods when the lake is covered by a thick crust. This stage dominates the activity of the lake more than 90 percent of the time. The results of this study are relevant for satellite and airborne measurement of the thermal characteristics of active volcanoes, and indicate that the thermal output of a lava lake varies on a time scale of seconds to minutes.

  2. Measurement and Applications of Radiation Pressure

    NASA Astrophysics Data System (ADS)

    Ma, Dakang; Garrett, Joseph; Murray, Joseph; Munday, Jeremy; Munday Lab Team

    Light reflected off a material or absorbed within it exerts radiation pressure through the transfer of momentum. Measuring and utilizing radiation pressure have aroused growing interest in a wide spectrum of research fields. Micromechanical transducers and oscillators are good candidates for measuring radiation pressure, but accompanying photothermal effects often obscure the measurement. In this work, we investigate the accurate measurement of the radiation force on microcantilevers in ambient conditions and ways to separate radiation pressure and photothermal effects. Further, we investigate an optically broadband switchable device based on polymer dispersed liquid crystal which has potential applications in solar sails and maneuvering spacecraft without moving parts. The authors would like to thank NASA Early Career Faculty Award and NASA Smallsat Technology Partnership Award for their funding support.

  3. Aerosol Profile Measurements from the NASA Langley Research Center Airborne High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Obland, Michael D.; Hostetler, Chris A.; Ferrare, Richard A.; Hair, John W.; Roers, Raymond R.; Burton, Sharon P.; Cook, Anthony L.; Harper, David B.

    2008-01-01

    Since achieving first light in December of 2005, the NASA Langley Research Center (LaRC) Airborne High Spectral Resolution Lidar (HSRL) has been involved in seven field campaigns, accumulating over 450 hours of science data across more than 120 flights. Data from the instrument have been used in a variety of studies including validation and comparison with the Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite mission, aerosol property retrievals combining passive and active instrument measurements, aerosol type identification, aerosol-cloud interactions, and cloud top and planetary boundary layer (PBL) height determinations. Measurements and lessons learned from the HSRL are leading towards next-generation HSRL instrument designs that will enable even further studies of aerosol intensive and extensive parameters and the effects of aerosols on the climate system. This paper will highlight several of the areas in which the NASA Airborne HSRL is making contributions to climate science.

  4. An intercomparison of airborne nitric oxide measurements - A second opportunity

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Hoell, James M., Jr.; Torres, Arnold L.; Carroll, Mary Anne; Ridley, Brian A.

    1990-01-01

    Results are reported from a comparison of three tropospheric NO measurement instruments during the NASA Global Tropospheric Experiment Chemical Instrumentation Test and Evaluation 2 (CITE 2) in summer 1986. The instruments tested were those used in CITE 1 (Hoell et al., 1987): a two-photon LIF system and two chemiluminescence systems. It is found that the mixing ratios obtained with the three systems agreed to within 15-20 parts per trillion volume (pptv) for sampling perods of 1-6 min at mixing ratios less than 20 pptv; the average difference between pairs of measurements was 5-7 pptv, which is considered to be the uncertainty in state-of-the-art ambient NO measurements.

  5. 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

  6. The measurement of radiation levels in Australian zircon milling plants.

    PubMed

    Hartley, B M

    2001-01-01

    The processing of zircon often involves grinding it to a fine powder known as zircon flour. As the resulting particles are small they may be inhaled if they become airborne and, since they contain some uranium and thorium, deliver radiation doses to workers. Theoretical estimates and measured radiation exposure in Australian zircon milling plants are reported in this paper. Theoretical doses, calculated in this work, indicate a potential maximum dose to workers of 5.5 mSv y(-1). Measured doses, based on normal work practices, vary in different plants from 0.66 mSv to 1.03 mSv y(-1) and suggest that in the dustiest Australian zircon milling plants the maximum dose would be of the order of 1 mSv y(-1). Measurements, which focused on the dustiest operations, indicate an upper limit of dose of about 3 mSv y(-1). Based on the theoretical and measured doses not exceeding 6 mSv y(-1), workers would not be designated as Category A workers, and probably would not be designated Category B workers, exceeding 1 mSv y(-1), under the guidelines of a EURATOM Directive.

  7. Airborne measurements of gas and particle pollutants during CAREBeijing-2008

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Zhu, T.; Yang, W.; Bai, Z.; Sun, Y. L.; Xu, Y.; Yin, B.; Zhao, X.

    2014-01-01

    Measurements of gaseous pollutants - including ozone (O3), sulfur dioxide (SO2), nitrogen oxides (NOX = NO + NO2), carbon monoxide (CO), particle number concentrations (5.6-560 nm and 0.47-30 μm) - and meteorological parameters (T, RH, P) were conducted during the Campaigns of Air Quality Research in Beijing and Surrounding Regions in 2008 (CAREBeijing-2008), from 27 August through 13 October 2008. The data from a total 18 flights (70 h flight time) from near the surface to 2100 m altitude were obtained with a Yun-12 aircraft in the southern surrounding areas of Beijing (38-40° N, 114-118° E). The objectives of these measurements were to characterize the regional variation of air pollution during and after the Olympics of 2008, determine the importance of air mass trajectories and to evaluate of other factors that influence the pollution characteristics. The results suggest that there are primarily four distinct sources that influenced the magnitude and properties of the pollutants in the measured region based on back-trajectory analysis: (1) southerly transport of air masses from regions with high pollutant emissions, (2) northerly and northeasterly transport of less pollutant air from further away, (3) easterly transport from maritime sources where emissions of gaseous pollutant are less than from the south but still high in particle concentrations, and (4) the transport of air that is a mixture from different regions; that is, the air at all altitudes measured by the aircraft was not all from the same sources. The relatively long-lived CO concentration is shown to be a possible transport tracer of long-range transport from the northwesterly direction, especially at the higher altitudes. Three factors that influenced the size distribution of particles - i.e., air mass transport direction, ground source emissions and meteorological influences - are also discussed.

  8. Experimental evidence of interhemispheric transport from airborne carbon monoxide measurements

    NASA Technical Reports Server (NTRS)

    Newell, R. E.; Gauntner, D. J.

    1979-01-01

    During the period 28-30 October 1977, a Pan American 747-SP aircraft flew around the world with an automated instrument package that included measurements of atmospheric CO made every 4 sec. The flight path extended from San Francisco, over the North Pole to London, south to Capetown, over the South Pole to Auckland, and back to San Francisco. The data collected show large changes with longitude, which are interpreted as direct evidence of interhemispheric mixing. Possible sources for CO are discussed.

  9. Airborne Validation of Spatial Properties Measured by the CALIPSO Lidar

    NASA Technical Reports Server (NTRS)

    McGill, Matthew J.; Vaughan, Mark A.; Trepte, Charles Reginald; Hart, William D.; Hlavka, Dennis L.; Winker, David M.; Keuhn, Ralph

    2007-01-01

    The primary payload onboard the Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) satellite is a dual-wavelength backscatter lidar designed to provide vertical profiling of clouds and aerosols. Launched in April 2006, the first data from this new satellite was obtained in June 2006. As with any new satellite measurement capability, an immediate post-launch requirement is to verify that the data being acquired is correct lest scientific conclusions begin to be drawn based on flawed data. A standard approach to verifying satellite data is to take a similar, or validation, instrument and fly it onboard a research aircraft. Using an aircraft allows the validation instrument to get directly under the satellite so that both the satellite instrument and the aircraft instrument are sensing the same region of the atmosphere. Although there are almost always some differences in the sampling capabilities of the two instruments, it is nevertheless possible to directly compare the measurements. To validate the measurements from the CALIPSO lidar, a similar instrument, the Cloud Physics Lidar, was flown onboard the NASA high-altitude ER-2 aircraft during July- August 2006. This paper presents results to demonstrate that the CALIPSO lidar is properly calibrated and the CALIPSO Level 1 data products are correct. The importance of the results is to demonstrate to the research community that CALIPSO Level 1 data can be confidently used for scientific research.

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

    PubMed

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

    1998-05-04

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

  11. Potential for airborne offbeam lidar measurements of snow and sea ice thickness

    NASA Astrophysics Data System (ADS)

    VáRnai, TamáS.; Cahalan, Robert F.

    2007-12-01

    This article discusses the capabilities and limitations of a new approach to airborne measurements of snow and sea ice thickness. Such measurements can help better understand snow and sea ice processes and can also contribute to the validation of satellite measurements. The approach discussed here determines physical snow and sea ice thickness by observing the horizontal spread of lidar pulses: The bright halo observed around an illuminated spot extends farther out in thicker layers because photons can travel longer without escaping through the bottom. Since earlier studies suggested the possibility of such sea ice retrievals, this article presents a theoretical analysis of additional uncertainties that arise in airborne observations of snow and sea ice. Snow and sea ice retrievals pose somewhat different challenges because while sea ice is usually much thicker, snow contains a much higher concentration of scatterers. As a result, sea ice halos are larger, but snow halos are brighter. The results indicate that airborne sea ice retrievals are possible at night and that snow retrievals are possible during both night and day. For snow thicknesses less than about 50 cm, observational issues, such as calibration uncertainty, can cause retrieval uncertainties on the order of 10% in 1-km-resolution retrievals. For moderate snow and sea ice thicknesses (<30 cm and 3 m, respectively), these issues cause similar (˜10%) uncertainties in sea ice thickness retrievals as well. These results indicate that offbeam lidars have the potential to become an important component of future snow and sea ice observing systems.

  12. Airborne measurements of organosulfates over the continental U.S.

    PubMed

    Liao, Jin; Froyd, Karl D; Murphy, Daniel M; Keutsch, Frank N; Yu, Ge; Wennberg, Paul O; St Clair, Jason M; Crounse, John D; Wisthaler, Armin; Mikoviny, Tomas; Jimenez, Jose L; Campuzano-Jost, Pedro; Day, Douglas A; Hu, Weiwei; Ryerson, Thomas B; Pollack, Ilana B; Peischl, Jeff; Anderson, Bruce E; Ziemba, Luke D; Blake, Donald R; Meinardi, Simone; Diskin, Glenn

    2015-04-16

    Organosulfates are important secondary organic aerosol (SOA) components and good tracers for aerosol heterogeneous reactions. However, the knowledge of their spatial distribution, formation conditions, and environmental impact is limited. In this study, we report two organosulfates, an isoprene-derived isoprene epoxydiols (IEPOX) (2,3-epoxy-2-methyl-1,4-butanediol) sulfate and a glycolic acid (GA) sulfate, measured using the NOAA Particle Analysis Laser Mass Spectrometer (PALMS) on board the NASA DC8 aircraft over the continental U.S. during the Deep Convective Clouds and Chemistry Experiment (DC3) and the Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS). During these campaigns, IEPOX sulfate was estimated to account for 1.4% of submicron aerosol mass (or 2.2% of organic aerosol mass) on average near the ground in the southeast U.S., with lower concentrations in the western U.S. (0.2-0.4%) and at high altitudes (<0.2%). Compared to IEPOX sulfate, GA sulfate was more uniformly distributed, accounting for about 0.5% aerosol mass on average, and may be more abundant globally. A number of other organosulfates were detected; none were as abundant as these two. Ambient measurements confirmed that IEPOX sulfate is formed from isoprene oxidation and is a tracer for isoprene SOA formation. The organic precursors of GA sulfate may include glycolic acid and likely have both biogenic and anthropogenic sources. Higher aerosol acidity as measured by PALMS and relative humidity tend to promote IEPOX sulfate formation, and aerosol acidity largely drives in situ GA sulfate formation at high altitudes. This study suggests that the formation of aerosol organosulfates depends not only on the appropriate organic precursors but also on emissions of anthropogenic sulfur dioxide (SO2), which contributes to aerosol acidity.

  13. Airborne Spectral Measurements of Ocean Anisotropy during CLAMS

    NASA Technical Reports Server (NTRS)

    Gatebe, C. K.; King, M. D.; Arnold, G. T.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    The Cloud Absorption Radiometer (CAR) aboard the University of Washington Convair CV-580 research aircraft obtained bidirectional reflectance-distribution function (BRDF) of Atlantic Ocean and Dismal Swamp between July 10 and August 2, 2001. The BRDF measurements (15 in total, 8 uncontaminated by clouds) obtained under a variety of sun angles and wind conditions, will be used to characterize ocean anisotropy in support of Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) science objectives principally to validate products from NASA's EOS satellites, and to parameterize and validate BRDF models of the ocean. In this paper we present results of BRDF of the Ocean under different sun angles and wind conditions. The CAR is capable of measuring scattered light in fourteen spectral bands. The scan mirror, rotating at 100 rpm, directs the light into a Dall-Kirkham telescope where the beam is split into nine paths. Eight light beams pass through beam splitters, dichroics, and lenses to individual detectors (0.34-1.27 micron), and finally are registered by eight data channels. They are sampled simultaneously and continuously. The ninth beam passes through a spinning filter wheel to an InSb detector cooled by a Stirling cycle cooler. Signals registered by the ninth data channel are selected from among six spectral channels (1.55-2.30 micron). The filter wheel can either cycle through all six spectral bands at a prescribed interval (usually changing filter every fifth scan line), or lock onto any one of the six spectral bands and sample it continuously. To measure the BRF of the surface-atmosphere system, the University of Washington CV-580 had to fly in a circle about 3 km in diameter above the surface for roughly two minutes. Replicated observations (multiple circular orbits) were acquired over selected surfaces so that average BRF smooth out small-scale surface and atmospheric inhomogeneities. At an altitude of 600 m above the targeted surface area and

  14. Airborne measurements of biomass burning products over Africa

    NASA Technical Reports Server (NTRS)

    Helas, Guenter; Lobert, Juergen; Goldammer, Johann; Andreae, Meinrat O.; Lacaux, J. P.; Delmas, R.

    1994-01-01

    Ozone has been observed in elevated concentrations by satellites over hitherto believed 'background' areas. There is meteorological evidence that these ozone 'plumes' found over the Atlantic ocean originate from biomass fires on the African continent. Therefore we have investigated ozone and assumed precursor compounds over African regions. The measurements revealed large photosmog layers in altitudes between 1.5 and 4 km. Here we will focus on some results of ozone mixing ratios obtained during the DECAFE 91/FOS experiment and estimate the relevance of biomass burning as a source by comparing the strength of this source to stratospheric input.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  16. Validation of Airborne FMCW Radar Measurements of Snow Thickness Over Sea Ice in Antarctica

    NASA Technical Reports Server (NTRS)

    Galin, Natalia; Worby, Anthony; Markus, Thorsten; Leuschen, Carl; Gogineni, Prasad

    2012-01-01

    Antarctic sea ice and its snow cover are integral components of the global climate system, yet many aspects of their vertical dimensions are poorly understood, making their representation in global climate models poor. Remote sensing is the key to monitoring the dynamic nature of sea ice and its snow cover. Reliable and accurate snow thickness data are currently a highly sought after data product. Remotely sensed snow thickness measurements can provide an indication of precipitation levels, predicted to increase with effects of climate change in the polar regions. Airborne techniques provide a means for regional-scale estimation of snow depth and distribution. Accurate regional-scale snow thickness data will also facilitate an increase in the accuracy of sea ice thickness retrieval from satellite altimeter freeboard estimates. The airborne data sets are easier to validate with in situ measurements and are better suited to validating satellite algorithms when compared with in situ techniques. This is primarily due to two factors: better chance of getting coincident in situ and airborne data sets and the tractability of comparison between an in situ data set and the airborne data set averaged over the footprint of the antennas. A 28-GHz frequency modulated continuous wave (FMCW) radar loaned by the Center for Remote Sensing of Ice Sheets to the Australian Antarctic Division is used to measure snow thickness over sea ice in East Antarctica. Provided with the radar design parameters, the expected performance parameters of the radar are summarized. The necessary conditions for unambiguous identification of the airsnow and snowice layers for the radar are presented. Roughnesses of the snow and ice surfaces are found to be dominant determinants in the effectiveness of layer identification for this radar. Finally, this paper presents the first in situ validated snow thickness estimates over sea ice in Antarctica derived from an FMCW radar on a helicopterborne platform.

  17. Lidar System for Airborne Measurement of Clouds and Aerosols

    NASA Technical Reports Server (NTRS)

    McGill, Matthew; Scott, V. Stanley; Izquierdo, Luis Ramos; Marzouk, Joe

    2008-01-01

    A lidar system for measuring optical properties of clouds and aerosols at three wavelengths is depicted. The laser transmitter is based on a Nd:YVO4 laser crystal pumped by light coupled to the crystal via optical fibers from laser diodes that are located away from the crystal to aid in dissipating the heat generated in the diodes and their drive circuits. The output of the Nd:YVO4 crystal has a wavelength of 1064 nm, and is made to pass through frequency-doubling and frequency-tripling crystals. As a result, the net laser output is a collinear superposition of beams at wavelengths of 1064, 532, and 355 nm. The laser operates at a pulse-repetition rate of 5 kHz, emitting per-pulse energies of 50 microJ at 1064 nm, 25 microJ at 532 nm and 50 microJ at 355 nm. An important feature of this system is an integrating sphere located between the laser output and the laser beam expander lenses. The integrating sphere collects light scattered from the lenses. Three energy-monitor detectors are located at ports inside the integrating sphere. Each of these detectors is equipped with filters such that the laser output energy is measured independently for each wavelength. The laser output energy is measured on each pulse to enable the most accurate calibration possible. The 1064-nm and 532-nm photodetectors are, more specifically, single photon-counting modules (SPCMs). When used at 1064 nm, these detectors have approximately 3% quantum efficiency and low thermal noise (fewer than 200 counts per second). When used at 532 nm, the SPCMs have quantum efficiency of about 60%. The photodetector for the 355-nm channel is a photon-counting photomultiplier tube having a quantum efficiency of about 20%. The use of photon-counting detectors is made feasible by the low laser pulse energy. The main advantage of photon-counting is ease of inversion of data without need for complicated calibration schemes like those necessary for analog detectors. The disadvantage of photon-counting detectors

  18. Passive Measurement of CO2 Column from an Airborne Platform

    NASA Technical Reports Server (NTRS)

    Heaps, William S.; Kawa, S. R.; Wilson, Emily; Georgleva, Elena

    2004-01-01

    We are in the third and final year of our IIP funding to develop a sensor for very precise determination of the CO2 Column. Global measurements of this sort from a satellite platform are needed to improve our understanding of the global carbon budget. In previous reports to this meeting we have described the method by which this system operates and presented data taken during ground based tests of the instrument. Work in the final year has concentrated on building the flight hardened version of the instrument that will be used in our field trials on the Dryden DC-8. The flight unit represents an integration of three channels into a single instrument. These three channels are the CO2 channel, the oxygen pressure sensing channel, and the oxygen temperature sensing channel. Integration of the three channels into a single unit significantly decreases the size of the instrument. The flight unit also employs more rugged optical mounts and integrated optical shielding. Light enters the instrument from below first striking the right angled mirror shown extending over the edge of the platform. The light is then focused through a pinhole to define the instrument field of view, chopped and recollimated. Dichroic mirrors are used to separate the CO2 wavelength from the O2 wavelength and that light is further divided by a 50-50 beamsplitter between the 2 oxygen channels - the pressure channel and the temperature channel. The six white boxes contain the detectors for each of the three channels. The detectors on the left in the photo serve the reference channels and the detectors on the right are for the Fabry-Perots. CO2 is measured by the pair of detectors farthest from the viewer. Pressure via O2 is detected by the central pair of detectors. The closest pair is used to determine temperature via O2.

  19. Aerosol-fluorescence spectrum analyzer: real-time measurement of emission spectra of airborne biological particles

    NASA Astrophysics Data System (ADS)

    Hill, Steven C.; Pinnick, Ronald G.; Nachman, Paul; Chen, Gang; Chang, Richard K.; Mayo, Michael W.; Fernandez, Gilbert L.

    1995-10-01

    We have assembled an aerosol-fluorescence spectrum analyzer (AFS), which can measure the fluorescence spectra and elastic scattering of airborne particles as they flow through a laser beam. The aerosols traverse a scattering cell where they are illuminated with intense (50 kW/cm 2) light inside the cavity of an argon-ion laser operating at 488 nm. This AFS can obtain fluorescence spectra of individual dye-doped polystyrene microspheres as small as 0.5 mu m in diameter. The spectra obtained from microspheres doped with pink and green-yellow dyes are clearly different. We have also detected the fluorescence spectra of airborne particles (although not single particles) made from various

  20. Downsizing of Georgia Tech's Airborne Fluorescence Spectrometer (AFS) for the Measurement of Nitrogen Oxides

    NASA Technical Reports Server (NTRS)

    Sandholm, Scott

    1998-01-01

    This report addresses the Tropospheric Trace Gas and Airborne Measurements (TTGAMG) endeavors to further downsize and stabilize the Georgia Institute of Technology's Airborne Laser Induced Fluorescence Experiment (GITALIFE). It will mainly address the TTGAMG successes and failures as participants in the summer 1998 Wallops Island test flights on board the P3-B. Due to the restructuring and reorganization of the TTGAMG since the original funding of this grant, some of the objectives and time lines of the deliverables have been changed. Most of these changes have been covered in the preceding annual report. We are anticipating getting back on track with the original proposal's downsizing effort this summer, culminating in the GITALIFE no longer occupying a high bay rack and the loss of several hundred pounds.

  1. Airborne Shaped Sonic Boom Demonstration Pressure Measurements with Computational Fluid Dynamics Comparisons

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.; Murray, James E.; Purifoy, Dana D.; Graham, David H.; Meredith, Keith B.; Ashburn, Christopher E.; Stucky, Mark

    2005-01-01

    The Shaped Sonic Boom Demonstration project showed for the first time that by careful design of aircraft contour the resultant sonic boom can maintain a tailored shape, propagating through a real atmosphere down to ground level. In order to assess the propagation characteristics of the shaped sonic boom and to validate computational fluid dynamics codes, airborne measurements were taken of the pressure signatures in the near field by probing with an instrumented F-15B aircraft, and in the far field by overflying an instrumented L-23 sailplane. This paper describes each aircraft and their instrumentation systems, the airdata calibration, analysis of the near- and far-field airborne data, and shows the good to excellent agreement between computational fluid dynamics solutions and flight data. The flights of the Shaped Sonic Boom Demonstration aircraft occurred in two phases. Instrumentation problems were encountered during the first phase, and corrections and improvements were made to the instrumentation system for the second phase, which are documented in the paper. Piloting technique and observations are also given. These airborne measurements of the Shaped Sonic Boom Demonstration aircraft are a unique and important database that will be used to validate design tools for a new generation of quiet supersonic aircraft.

  2. Rapid assessment of water pollution by airborne measurement of chlorophyll content.

    NASA Technical Reports Server (NTRS)

    Arvesen, J. C.; Weaver, E. C.; Millard, J. P.

    1971-01-01

    Present techniques of airborne chlorophyll measurement are discussed as an approach to water pollution assessment. The differential radiometer, the chlorophyll correlation radiometer, and an infrared radiometer for water temperature measurements are described as the key components of the equipment. Also covered are flight missions carried out to evaluate the capability of the chlorophyll correlation radiometer in measuring the chlorophyll content in water bodies with widely different levels of nutrients, such as fresh-water lakes of high and low eutrophic levels, marine waters of high and low productivity, and an estuary with a high sediment content. The feasibility and usefulness of these techniques are indicated.

  3. Double-Pulse Two-Micron IPDA Lidar Simulation for Airborne Carbon Dioxide Measurements

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta

    2015-01-01

    An advanced double-pulsed 2-micron integrated path differential absorption lidar has been developed at NASA Langley Research Center for measuring atmospheric carbon dioxide. The instrument utilizes a state-of-the-art 2-micron laser transmitter with tunable on-line wavelength and advanced receiver. Instrument modeling and airborne simulations are presented in this paper. Focusing on random errors, results demonstrate instrument capabilities of performing precise carbon dioxide differential optical depth measurement with less than 3% random error for single-shot operation from up to 11 km altitude. This study is useful for defining CO2 measurement weighting, instrument setting, validation and sensitivity trade-offs.

  4. Coordinated analysis of various auroral measurements made during NASA's 1968 and 1969 airborne auroral expeditions

    NASA Technical Reports Server (NTRS)

    Sivjee, G. G.

    1976-01-01

    Auroral optical measurements made aboard NASA's CV 990 were analyzed. The measurements analyzed form a small part of extensive spectroscopic, photometric and photographic data gathered during the 1968 and 1969 Airborne Auroral Expeditions. Simultaneous particle measurements from ESRO IA satellite were used in the analysis. Information about magnetospheric boundaries, interaction between magnetosheath particles and the terrestrial ionosphere, the polar bulge in helium abundance and excitation mechanisms of the triplet state of atmospheric N2 in auroras was obtained. Further analysis of the data is required to elucidate the relation between 3466 and 5200 A emissions of NI and the excitation of 3726-3729 A emissions from atomic oxygen ions in auroras.

  5. Temperature and wind measurements and model atmospheres of the 1989 Airborne Arctic Stratospheric Expedition

    NASA Technical Reports Server (NTRS)

    Chan, K. R.; Bui, T. P.; Scott, S. G.; Bowen, S. W.; Dean-Day, J.

    1990-01-01

    The ER-2 Meteorological Measurement System provides accurate in situ measurements of atmospheric state variables. During the Airborne Arctic Stratospheric Expedition (AASE) the ER-2 flew over the polar region on 14 occasions in January and February, 1989. Vertical temperature profiles, during aircraft takeoff at about 60 deg N and during midflight descent and ascent at high latitudes, are presented. Latitudinal variations of the horizontal wind measurement are illustrated and discussed. Based on observation data, model atmospheres at 60 deg and 75 deg N, representative of the environment of the AASE campaign, are developed.

  6. Towards understanding of shatter artifacts in airborne sampling inlets: Analysis of aerosol-cloud measurements

    NASA Astrophysics Data System (ADS)

    Craig, Lucas

    Atmospheric aerosols have a critical role in Earth's radiative balance through both direct and indirect effects. The direct effect of aerosols is to scatter or absorb shortwave and longwave radiation, while the indirect effect results from the role of aerosols in cloud formation. Accurate modeling of long-term global climate change requires complete knowledge of both the direct and indirect effects of atmospheric aerosol. For measurement of atmospheric aerosol and aerosol-cloud systems, aircraft sampling has been found to be the most suitable. Aircraft measurements of aerosol particles inside cloud systems are often observed to be unrealistically high. This is because, the breakup of cloud droplets creates shatter artifact particles of sizes in the same range as that of interstitial particles being sampled, resulting in the enhancement of aerosol number concentration measurements in clouds. Cloud droplet breakup results from two primary mechanisms: wall impaction and aerodynamic forces. The first mechanism is produced when a cloud droplet collides with the inlet surface and the later occurs from significant acceleration or deceleration of cloud droplets relative to the local airstream. Because of cloud droplet breakup and the resultant produce of shattered particles, atmospheric scientists discard in-cloud data, and this has limited our ability to fully characterize different kinds of aerosol-cloud systems. As part of this thesis, the extent of the shatter artifact problem in existing aerosol-cloud inlets is examined and a methodology using computational fluid dynamics (CFD) for finding their operating limits is established. Measurements from several different inlet systems, including: NCAR's Sub-micron Aerosol Inlet (SMAI) and HIAPER modular inlet (HIMIL), Clarkson's High Cross-flow Aerosol Sampler (Hi-CAS), and the Clarke Solid Diffuser inlet (Clarke SD), are analyzed to determine measurement artifacts associated with sampling in clouds. The results indicate that

  7. Terrestrial and Airborne LIDAR: Comparison of Coincident Datasets for Measuring Ground Deformation and Topographic Change

    NASA Astrophysics Data System (ADS)

    Kayen, R. E.; Stewart, J. P.; Lembo, A. J.; Hu, J.; Davis, C. A.; Hogue, T.; Collins, B. D.; Minasian, D.; Louis-Kayen, N. M.; O'Rourke, T. D.

    2009-05-01

    We present the results from a controlled study on the use of pulse-based terrestrial lidar and phase-based airborne lidar to detect topographic change and ground deformation in areas of earthquake- and storm- induced landslides. Terrestrial and airborne lidar scans were performed at three sites in Los Angeles County and their accuracy was gauged using coincident total station survey measurements as the control. The study was supported by the Multidisciplinary Center for Earthquake Engineering Research (MCEER), the National Science Foundation (NSF), and the Los Angeles Department of Water and Power (LADWP). Horizontal accuracy was evaluated through the measurement of Northing and Easting residuals, standardized to WGS84. Assessment of accuracy was made on lengths and heights of well-defined objects in the lidar scans, such as LADWP buildings and water tanks. The bias and dispersion of lidar height measurements, standardized to NGVD88, were assessed at the Mulholland Tank adjacent to Hollywood Reservoir, the Owens Aqueduct Penstock at Power Plant 2 (PP2) in San Francisquito Canyon, and a flat un-vegetated site near the Los Angeles Reservoir before and after carefully measured trenching. At the vegetated slopes near PP2 and the Hollywood Reservoir site, airborne lidar showed minimal elevation bias and a standard deviation of approximately 50 cm, whereas terrestrial lidar demonstrated large bias and dispersion (on order of meters) due to the inability of ground-based lidar to penetrate heavy vegetation. Both systems were able to assess heights and lengths on unobstructed man made structures at the sub-decimeter scale. At the trench site, airborne lidar showed decimeter scale bias of -23.6 cm for flat ground to -8.7 cm for trenched ground, and dispersion of 5.6 for flat ground to 20 cm for trenched ground. Terrestrial lidar was nearly unbiased (~0 cm for flat or trenched ground) and with very low dispersion of 4.1 and 6.5 cm for flat and trenched ground, respectively

  8. Airborne lidar measurements of El Chichon stratospheric aerosols

    NASA Technical Reports Server (NTRS)

    Mccormick, M. P.; Osborn, M. T.

    1985-01-01

    A NASA Electra airplane, outfitted with a lidar system, was flown in January to February 1983 between the latitudes of 27 deg N and 76 deg N. One of the primary purposes of this mission was to determine the spatial distribution and aerosol characteristics of the El Chichon-produced stratospheric material. This report presents the lidar data from that flight mission. Representative profiles of lidar backscatter ratio, plots of the integrated backscattering function versus latitude, and contours of backscatter mixing ratio versus altitude and latitude are given. It addition, tables containing numerical values of the backscatter ratio and backscattering function versus altitude are supplied for each profile. The largest amount of material produced by the El Chichon eruptions of late March to early April 1982, which was measured by this flight, resided between 35 deg N and 52 deg N. Peak backscatter ratios at a wavelength of 0.6943 micro m decreased from 8 to 10 at the lower latitudes to 3 at the higher latitudes. Backscatter ratio profiles taken while crossing the polar vortex show that the high-altitude material from El Chichon arrived at the north polar region sometime after the winter polar vortex was established. This report presents the results of this mission in a ready-to-use format for atmospheric and climatic studies.

  9. Portable Airborne Laser System Measures Forest-Canopy Height

    NASA Technical Reports Server (NTRS)

    Nelson, Ross

    2005-01-01

    (PALS) is a combination of laser ranging, video imaging, positioning, and data-processing subsystems designed for measuring the heights of forest canopies along linear transects from tens to thousands of kilometers long. Unlike prior laser ranging systems designed to serve the same purpose, the PALS is not restricted to use aboard a single aircraft of a specific type: the PALS fits into two large suitcases that can be carried to any convenient location, and the PALS can be installed in almost any local aircraft for hire, thereby making it possible to sample remote forests at relatively low cost. The initial cost and the cost of repairing the PALS are also lower because the PALS hardware consists mostly of commercial off-the-shelf (COTS) units that can easily be replaced in the field. The COTS units include a laser ranging transceiver, a charge-coupled-device camera that images the laser-illuminated targets, a differential Global Positioning System (dGPS) receiver capable of operation within the Wide Area Augmentation System, a video titler, a video cassette recorder (VCR), and a laptop computer equipped with two serial ports. The VCR and computer are powered by batteries; the other units are powered at 12 VDC from the 28-VDC aircraft power system via a low-pass filter and a voltage converter. The dGPS receiver feeds location and time data, at an update rate of 0.5 Hz, to the video titler and the computer. The laser ranging transceiver, operating at a sampling rate of 2 kHz, feeds its serial range and amplitude data stream to the computer. The analog video signal from the CCD camera is fed into the video titler wherein the signal is annotated with position and time information. The titler then forwards the annotated signal to the VCR for recording on 8-mm tapes. The dGPS and laser range and amplitude serial data streams are processed by software that displays the laser trace and the dGPS information as they are fed into the computer, subsamples the laser range and

  10. XUV polarimeter for undulator radiation measurements

    SciTech Connect

    Gluskin, E.; Mattson, J.E.; Bader, S.D.; Viccaro, P.J. ); Barbee, T.W. Jr. ); Brookes, N. ); Pitas, A. ); Watts, R. )

    1991-01-01

    A polarimeter for x-ray and vacuum ultraviolet (XUV) radiation was built to measure the spatial spectral dependence of the polarization of the light produced by the new undulator at the U5 beamline at NSLS. The fourth-harmonic radiation was measured, and it does not agree with predictions based on ideal simulation codes in the far-field approximation. 13 ref., 7 figs.

  11. Airborne and Ground-Based Measurements Using a High-Performance Raman Lidar

    NASA Technical Reports Server (NTRS)

    Whiteman, David N.; Rush, Kurt; Rabenhorst, Scott; Welch, Wayne; Cadirola, Martin; McIntire, Gerry; Russo, Felicita; Adam, Mariana; Venable, Demetrius; Connell, Rasheen; Veselovskii, Igor; Forno, Ricardo; Mielke, Bernd; Stein, Bernhard; Leblanc, Thierry; McDermid, Stuart; Voemel, Holger

    2010-01-01

    A high-performance Raman lidar operating in the UV portion of the spectrum has been used to acquire, for the first time using a single lidar, simultaneous airborne profiles of the water vapor mixing ratio, aerosol backscatter, aerosol extinction, aerosol depolarization and research mode measurements of cloud liquid water, cloud droplet radius, and number density. The Raman Airborne Spectroscopic Lidar (RASL) system was installed in a Beechcraft King Air B200 aircraft and was flown over the mid-Atlantic United States during July August 2007 at altitudes ranging between 5 and 8 km. During these flights, despite suboptimal laser performance and subaperture use of the telescope, all RASL measurement expectations were met, except that of aerosol extinction. Following the Water Vapor Validation Experiment Satellite/Sondes (WAVES_2007) field campaign in the summer of 2007, RASL was installed in a mobile trailer for groundbased use during the Measurements of Humidity and Validation Experiment (MOHAVE-II) field campaign held during October 2007 at the Jet Propulsion Laboratory s Table Mountain Facility in southern California. This ground-based configuration of the lidar hardware is called Atmospheric Lidar for Validation, Interagency Collaboration and Education (ALVICE). During theMOHAVE-II field campaign, during which only nighttime measurements were made, ALVICE demonstrated significant sensitivity to lower-stratospheric water vapor. Numerical simulation and comparisons with a cryogenic frost-point hygrometer are used to demonstrate that a system with the performance characteristics of RASL ALVICE should indeed be able to quantify water vapor well into the lower stratosphere with extended averaging from an elevated location like Table Mountain. The same design considerations that optimize Raman lidar for airborne use on a small research aircraft are, therefore, shown to yield significant dividends in the quantification of lower-stratospheric water vapor. The MOHAVE

  12. Development of airborne eddy-correlation flux measurement capabilities for reactive oxides of nitrogen

    NASA Technical Reports Server (NTRS)

    Bradshaw, John (Principal Investigator); Zheng, Xiaonan; Sandholm, Scott T.

    1996-01-01

    This research is aimed at producing a fundamental new research tool for characterizing the source strength of the most important compound controlling the hemispheric and global scale distribution of tropospheric ozone. Specifically, this effort seeks to demonstrate the proof-of-concept of a new general purpose laser-induced fluorescence based spectrometer for making airborne eddy-correlation flux measurements of nitric oxide (NO) and other reactive nitrogen compounds. The new all solid-state laser technology being used in this advanced sensor will produce a forerunner of the type of sensor technology that should eventually result in highly compact operational systems. The proof-of-concept sensor being developed will have over two orders-of-magnitude greater sensitivity than present-day instruments. In addition, this sensor will offer the possibility of eventual extension to airborne eddy-correlation flux measurements of nitrogen dioxide (NO2) and possibly other compounds, such as ammonia (NH3), peroxyradicals (HO2), nitrateradicals (NO3) and several iodine compounds (e.g., I and IO). Demonstration of the new sensor's ability to measure NO fluxes will occur through a series of laboratory and field tests. This proof-of-concept demonstration will show that not only can airborne fluxes of important ultra-trace compounds be made at the few parts-per-trillion level, but that the high accuracy/precision measurements currently needed for predictive models can also. These measurement capabilities will greatly enhance our current ability to quantify the fluxes of reactive nitrogen into the troposphere and significantly impact upon the accuracy of predictive capabilities to model O3's distribution within the remote troposphere. This development effort also offers a timely approach for producing the reactive nitrogen flux measurement capabilities that will be needed by future research programs such as NASA's planned 1999 Amazon Biogeochemistry and Atmospheric Chemistry

  13. Investigating seasonal methane emissions in Northern California using airborne measurements and inverse modeling

    NASA Astrophysics Data System (ADS)

    Johnson, Matthew S.; Xi, Xin; Jeong, Seongeun; Yates, Emma L.; Iraci, Laura T.; Tanaka, Tomoaki; Loewenstein, Max; Tadić, Jovan M.; Fischer, Marc L.

    2016-11-01

    Seasonal methane (CH4) emissions in Northern California are evaluated during this study by using airborne measurement data and inverse model simulations. This research applies Alpha Jet Atmospheric eXperiment (AJAX) measurements obtained during January-February 2013, July 2014, and October-November 2014 over the San Francisco Bay Area (SFBA) and northern San Joaquin Valley (SJV) in order to constrain seasonal CH4 emissions in Northern California. The California Greenhouse Gas Emissions Measurement (CALGEM) a priori emission inventory was applied in conjunction with the Weather Research and Forecasting and Stochastic Time-Inverted Lagrangian Transport model and inverse modeling techniques to optimize CH4 emissions. Comparing model-predicted CH4 mixing ratios with airborne measurements, we find substantial underestimates suggesting that CH4 emissions were likely larger than the year 2008 a priori CALGEM emission inventory in Northern California. Using AJAX measurements to optimize a priori emissions resulted in CH4 flux estimates from the SFBA/SJV of 1.77 ± 0.41, 0.83 ± 0.31, and 1.06 ± 0.39 Tg yr-1 when using winter, summer, and fall flight data, respectively. Averaging seasonal a posteriori emission estimates (weighted by posterior uncertainties) results in SFBA/SJV annual CH4 emissions of 1.28 ± 0.38 Tg yr-1. A posteriori uncertainties are reduced more effectively in the SFBA/SJV region compared to state-wide values indicating that the airborne measurements are most sensitive to emissions in this region. A posteriori estimates during this study suggest that dairy livestock was the source with the largest increase relative to the a priori CALGEM emission inventory during all seasons.

  14. On the impact of a refined stochastic model for airborne LiDAR measurements

    NASA Astrophysics Data System (ADS)

    Bolkas, Dimitrios; Fotopoulos, Georgia; Glennie, Craig

    2016-09-01

    Accurate topographic information is critical for a number of applications in science and engineering. In recent years, airborne light detection and ranging (LiDAR) has become a standard tool for acquiring high quality topographic information. The assessment of airborne LiDAR derived DEMs is typically based on (i) independent ground control points and (ii) forward error propagation utilizing the LiDAR geo-referencing equation. The latter approach is dependent on the stochastic model information of the LiDAR observation components. In this paper, the well-known statistical tool of variance component estimation (VCE) is implemented for a dataset in Houston, Texas, in order to refine the initial stochastic information. Simulations demonstrate the impact of stochastic-model refinement for two practical applications, namely coastal inundation mapping and surface displacement estimation. Results highlight scenarios where erroneous stochastic information is detrimental. Furthermore, the refined stochastic information provides insights on the effect of each LiDAR measurement in the airborne LiDAR error budget. The latter is important for targeting future advancements in order to improve point cloud accuracy.

  15. Evaluation of arctic broadband surface radiation measurements

    NASA Astrophysics Data System (ADS)

    Matsui, N.; Long, C. N.; Augustine, J.; Halliwell, D.; Uttal, T.; Longenecker, D.; Nievergall, O.; Wendell, J.; Albee, R.

    2011-08-01

    The Arctic is a challenging environment for making in-situ radiation measurements. A standard suite of radiation sensors is typically designed to measure the total, direct and diffuse components of incoming and outgoing broadband shortwave (SW) and broadband thermal infrared, or longwave (LW) radiation. Enhancements can include various sensors for measuring irradiance in various narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that rotate sensors and shading devices that track the sun. High quality measurements require striking a balance between locating sensors in a pristine undisturbed location free of artificial blockage (such as buildings and towers) and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data include solar tracker malfunctions, rime/frost/snow deposition on the instruments and operational problems due to limited operator access in extreme weather conditions. In this study, a comparison is made between the global and component sum (direct [vertical component] + diffuse) shortwave measurements. The difference between these two quantities (that theoretically should be zero) is used to illustrate the magnitude and seasonality of radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both shortwave and longwave measurements. Solutions to these operational problems are proposed that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols.

  16. Evaluation of Arctic broadband surface radiation measurements

    NASA Astrophysics Data System (ADS)

    Matsui, N.; Long, C. N.; Augustine, J.; Halliwell, D.; Uttal, T.; Longenecker, D.; Niebergall, O.; Wendell, J.; Albee, R.

    2012-02-01

    The Arctic is a challenging environment for making in-situ surface radiation measurements. A standard suite of radiation sensors is typically designed to measure incoming and outgoing shortwave (SW) and thermal infrared, or longwave (LW), radiation. Enhancements may include various sensors for measuring irradiance in narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that keep sensors and shading devices trained on the sun along its diurnal path. High quality measurements require striking a balance between locating stations in a pristine undisturbed setting free of artificial blockage (such as from buildings and towers) and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data in the Arctic include solar tracker malfunctions, rime/frost/snow deposition on the protective glass domes of the radiometers and operational problems due to limited operator access in extreme weather conditions. In this study, comparisons are made between the global and component sum (direct [vertical component] + diffuse) SW measurements. The difference between these two quantities (that theoretically should be zero) is used to illustrate the magnitude and seasonality of arctic radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both SW and LW measurements. Solutions to these operational problems that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols are proposed.

  17. Evaluation of Arctic Broadband Surface Radiation Measurements

    SciTech Connect

    Matsui, N.; Long, Charles N.; Augustine, J. A.; Halliwell, D.; Uttal, Taneil; Longenecker, D.; Niebergale, J.; Wendell, J.; Albee, R.

    2012-02-24

    The Arctic is a challenging environment for making in-situ radiation measurements. A standard suite of radiation sensors is typically designed to measure the total, direct and diffuse components of incoming and outgoing broadband shortwave (SW) and broadband thermal infrared, or longwave (LW) radiation. Enhancements can include various sensors for measuring irradiance in various narrower bandwidths. Many solar radiation/thermal infrared flux sensors utilize protective glass domes and some are mounted on complex mechanical platforms (solar trackers) that rotate sensors and shading devices that track the sun. High quality measurements require striking a balance between locating sensors in a pristine undisturbed location free of artificial blockage (such as buildings and towers) and providing accessibility to allow operators to clean and maintain the instruments. Three significant sources of erroneous data include solar tracker malfunctions, rime/frost/snow deposition on the instruments and operational problems due to limited operator access in extreme weather conditions. In this study, a comparison is made between the global and component sum (direct [vertical component] + diffuse) shortwave measurements. The difference between these two quantities (that theoretically should be zero) is used to illustrate the magnitude and seasonality of radiation flux measurement problems. The problem of rime/frost/snow deposition is investigated in more detail for one case study utilizing both shortwave and longwave measurements. Solutions to these operational problems are proposed that utilize measurement redundancy, more sophisticated heating and ventilation strategies and a more systematic program of operational support and subsequent data quality protocols.

  18. Atmospheric Radiation Measurement (ARM) Data from the ARM Aerial Facility

    DOE Data Explorer

    The Atmospheric Radiation Measurement (ARM) Program is the largest global change research program supported by the U.S. Department of Energy. The primary goal of the ARM Program is to improve the treatment of cloud and radiation physics in global climate models in order to improve the climate simulation capabilities of these models. ARM data is collected both through permanent monitoring stations and field campaigns around the world. Airborne measurements required to answer science questions from researchers or to validate ground data are also collected. To find data from all categories of aerial operations, follow the links from the AAF information page at http://www.arm.gov/sites/aaf. Tables of information will provide start dates, duration, lead scientist, and the research site for each of the named campaigns. The title of a campaign leads, in turn, to a project description, contact information, and links to the data. Users will be requested to create a password, but the data files are free for viewing and downloading. The ARM Archive physically resides at the Oak Ridge National Laboratory.

  19. Pressure Measurements Using an Airborne Differential Absorption Lidar. Part 1; Analysis of the Systematic Error Sources

    NASA Technical Reports Server (NTRS)

    Flamant, Cyrille N.; Schwemmer, Geary K.; Korb, C. Laurence; Evans, Keith D.; Palm, Stephen P.

    1999-01-01

    Remote airborne measurements of the vertical and horizontal structure of the atmospheric pressure field in the lower troposphere are made with an oxygen differential absorption lidar (DIAL). A detailed analysis of this measurement technique is provided which includes corrections for imprecise knowledge of the detector background level, the oxygen absorption fine parameters, and variations in the laser output energy. In addition, we analyze other possible sources of systematic errors including spectral effects related to aerosol and molecular scattering interference by rotational Raman scattering and interference by isotopic oxygen fines.

  20. Airborne Measurements of Atmospheric Methane Column Abundance Made Using a Pulsed IPDA Lidar

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Numata, Kenji; Li, Steve; Wu, Stewart; Ramanathan, Anamd; Dawsey, Martha; Mao, Jianping; Kawa, Randolph; Abshire, James B.

    2012-01-01

    We report airborne measurements of the column abundance of atmospheric methane made over an altitude range of 3-11 km using a direct detection IPDA lidar with a pulsed laser emitting at 1651 nm. The laser transmitter was a tunable, seeded optical parametric amplifier (OPA) pumped by a Nd:YAG laser and the receiver used a photomultiplier detector and photon counting electronics. The results follow the expected changes with aircraft altitude and the measured line shapes and optical depths show good agreement with theoretical calculations.

  1. Development of an Airborne Sea Ice Thickness Measurement System and Field Test Results

    DTIC Science & Technology

    1989-12-01

    Kovacs and J . Scott Holladay PJTIS CRA&I DTIC TAB Unannronced JustiCaton By Distribution I AvaIabilit Cordes AvjII d-dlc, Dist Prepared for U.S...Development of an Airborne Sea Ice Thickness Measurement System and Field Test Results 12. PERSONAL AUTHOR(S) Kovacs, Austin and Holladay, J . Scott 13a...Thickness Measurement System and Field Test Results AUSTIN KOVACS AND J . SCOTT HOLLADAY INTRODUCTION was determined to be desirable. The goals of the 1986-87

  2. Airborne Passive Microwave Measurements from the AMISA 2008 Science Campaign for Modeling of Arctic Sea Ice Heating

    NASA Astrophysics Data System (ADS)

    Zucker, M. L.; Gasiewski, A. J.; CenterEnvironmental Technology

    2011-12-01

    While climate changes in the Arctic are occurring more rapidly than anywhere else on Earth model-based predictions of sea ice extent are at once both more optimistic than the data suggest and exhibit a high degree of variability. It is believed that this high level of uncertainty is the result of an inadequate quantitative understanding of surface heating mechanisms, which in large part is due to a lack of high spatial resolution data on boundary layer and surface energy processes during melt and freezeup. In August 2008 the NASA Arctic Mechanisms of Interactions between the Surface and Atmosphere (AMISA) campaign, in conjunction with the Swedish-led Arctic Summer Cloud-Ocean Study (ASCOS) conducted coordinated high spatial resolution measurements of geophysical parameters in the Arctic relevant to atmospheric-sea ice interaction. The IPY-approved AMISA campaign used airborne radiometers, including the Polarimetric Scanning Radiometer (PSR) system, a suite of L-band to V-band fixed-beam radiometers for cloud liquid and water vapor measurement, short and longwave radiation sensors, meteorological parameters from cloud size distribution probes, GPS dropsondes, and aerosol sensors. Calibration of the PSR is achieved through periodic observations of stable references such as thermal blackbody targets and noise diodes. A combination of methods using both infrequent external thermal blackbody views and brief frequent internal noise sources has proven practical for airborne systems such as the PSR and is proposed for spaceborne systems such as GeoMAS. Once radiometric data is calibrated it is then rasterized into brightness temperature images which are then geo-located and imported into Google EarthTM. An example brightness temperature map from the AMISA 2008 campaign is included in this abstract. The analysis of this data provides a basis for the development of a heat flux model needed to decrease the uncertainly in weather and climate predictions within the Arctic. In

  3. Comparison of Retracking Algorithms Using Airborne Radar and Laser Altimeter Measurements of the Greenland Ice Sheet

    NASA Technical Reports Server (NTRS)

    Ferraro, Ellen J.; Swift, Calvin T.

    1995-01-01

    This paper compares four continental ice sheet radar altimeter retracking algorithms using airborne radar and laser altimeter data taken over the Greenland ice sheet in 1991. The refurbished Advanced Application Flight Experiment (AAFE) airborne radar altimeter has a large range window and stores the entire return waveform during flight. Once the return waveforms are retracked, or post-processed to obtain the most accurate altitude measurement possible, they are compared with the high-precision Airborne Oceanographic Lidar (AOL) altimeter measurements. The AAFE waveforms show evidence of varying degrees of both surface and volume scattering from different regions of the Greenland ice sheet. The AOL laser altimeter, however, obtains a return only from the surface of the ice sheet. Retracking altimeter waveforms with a surface scattering model results in a good correlation with the laser measurements in the wet and dry-snow zones, but in the percolation region of the ice sheet, the deviation between the two data sets is large due to the effects of subsurface and volume scattering. The Martin et al model results in a lower bias than the surface scattering model, but still shows an increase in the noise level in the percolation zone. Using an Offset Center of Gravity algorithm to retrack altimeter waveforms results in measurements that are only slightly affected by subsurface and volume scattering and, despite a higher bias, this algorithm works well in all regions of the ice sheet. A cubic spline provides retracked altitudes that agree with AOL measurements over all regions of Greenland. This method is not sensitive to changes in the scattering mechanisms of the ice sheet and it has the lowest noise level and bias of all the retracking methods presented.

  4. NASA Airborne Snow Observatory: Measuring Spatial Distribution of Snow Water Equivalent and Snow Albedo

    NASA Astrophysics Data System (ADS)

    Joyce, M.; Painter, T. H.; Mattmann, C. A.; Ramirez, P.; Laidlaw, R.; Bormann, K. J.; Skiles, M.; Richardson, M.; Berisford, D. F.

    2015-12-01

    The two most critical properties for understanding snowmelt runoff and timing are the spatial and temporal distributions of snow water equivalent (SWE) and snow albedo. Despite their importance in controlling volume and timing of runoff, snowpack albedo and SWE are still largely unquantified in the US and not at all in most of the globe, leaving runoff models poorly constrained. NASA Jet Propulsion Laboratory, in partnership with the California Department of Water Resources, has developed the Airborne Snow Observatory (ASO), an imaging spectrometer and scanning LiDAR system, to quantify SWE and snow albedo, generate unprecedented knowledge of snow properties for cutting edge cryospheric science, and provide complete, robust inputs to water management models and systems of the future. This poster will describe the NASA Airborne Snow Observatory, its outputs and their uses and applications, along with recent advancements to the system and plans for the project's future. Specifically, we will look at how ASO uses its imaging spectrometer to quantify spectral albedo, broadband albedo, and radiative forcing by dust and black carbon in snow. Additionally, we'll see how the scanning LiDAR is used to determine snow depth against snow-free acquisitions and to quantify snow water equivalent when combined with in-situ constrained modeling of snow density.

  5. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade

  6. Characterization of shallow marine convection in subtropical regions by airborne and spaceborne lidar measurements

    NASA Astrophysics Data System (ADS)

    Gross, Silke; Gutleben, Manuel; Schäfler, Andreas; Kiemle, Christoph; Wirth, Martin; Hirsch, Lutz; Ament, Felix

    2016-04-01

    One of the biggest challenges in present day climate research is still the quantification of cloud feedbacks in climate models. Especially the feedback from marine cumulus clouds in the boundary layer with maximum cloud top heights of 4 km introduces large uncertainties in climate sensitivity. Therefore a better understanding of these shallow marine clouds, as well as of their interaction with aerosols and the Earth's energy budget is demanded. To improve our knowledge of shallow marine cumulus convection, measurements onboard the German research aircraft HALO were performed during the NARVAL (Next-generation Aircraft Remote-sensing for Validation studies) mission in December 2013. During NARVAL an EarthCARE equivalent remote sensing payload, with the DLR airborne high spectral resolution and differential absorption lidar system WALES and the cloud radar of the HAMP (HALO Microwave Package) as its core instrumentation, was deployed. To investigate the capability of spaceborne lidar measurements for this kind of study several CALIOP underflights were performed. We will present a comparison of airborne and spaceborne lidar measurements, and we will present the vertical and horizontal distribution of the clouds during NARVAL based on lidar measurements. In particular we investigate the cloud top distribution and the horizontal cloud and cloud gap length. Furthermore we study the representativeness of the NARVAL data by comparing them to and analysing a longer time series and measurements at different years and seasons.

  7. The airborne Laser Absorption Spectrometer - A new instrument of remote measurement of atmospheric trace gases

    NASA Technical Reports Server (NTRS)

    Shumate, M. S.; Menzies, R. T.

    1978-01-01

    The Laser Absorption Spectrometer is a portable instrument developed by JPL for remote measurement of trace gases from an aircraft platform. It contains two carbon dioxide lasers, two optical heterodyne receivers, appropriate optics to aim the lasers at the ground and detect the backscattered energy, and signal processing and recording electronics. Operating in the differential-absorption mode, it is possible to monitor one atmospheric gas at a time and record the data in real time. The system can presently measure ozone, ethylene, water vapor, and chlorofluoromethanes with high sensitivity. Airborne measurements were made in early 1977 from the NASA/JPL twin-engine Beechcraft and in May 1977 from the NASA Convair 990 during the ASSESS-II Shuttle Simulation Study. These flights resulted in measurements of ozone concentrations in the lower troposphere which were compared with ground-based values provided by the Air Pollution Control District. This paper describes the details of the instrument and results of the airborne measurements.

  8. Airborne Lidar measurements of the atmospheric pressure profile with tunable Alexandrite lasers

    NASA Technical Reports Server (NTRS)

    Korb, C. L.; Schwemmer, G. K.; Dombrowski, M.; Milrod, J.; Walden, H.

    1986-01-01

    The first remote measurements of the atmospheric pressure profile made from an airborne platform are described. The measurements utilize a differential absorption lidar and tunable solid state Alexandrite lasers. The pressure measurement technique uses a high resolution oxygen A band where the absorption is highly pressure sensitive due to collision broadening. Absorption troughs and regions of minimum absorption were used between pairs of stongly absorption lines for these measurements. The trough technique allows the measurement to be greatly desensitized to the effects of laser frequency instabilities. The lidar system was set up to measure pressure with the on-line laser tuned to the absorption trough at 13147.3/cm and with the reference laser tuned to a nonabsorbing frequency near 13170.0/cm. The lidar signal returns were sampled with a 200 range gate (30 vertical resoltion) and averaged over 100 shots.

  9. Airborne measurements performed by a light aircraft during Pegasos spring 2013 campaign

    NASA Astrophysics Data System (ADS)

    Väänänen, Riikka; Krejci, Radovan; Manninen, Hanna E.; Nieminen, Tuomo; Yli-Juuti, Taina; Kangasluoma, Juha; Pohja, Toivo; Aalto, Pasi P.; Petäjä, Tuukka; Kulmala, Markku

    2014-05-01

    To fully understand the chemical and physical processes in atmosphere, measuring only on-ground is not sufficient. To extend the measurements into the lower troposphere, the University of Helsinki has performed airborne campaigns since 2009. During spring 2013, a light aircraft was used to measure the aerosol size distribution over boreal forests as a part of the Pegasos 'Norhern Mission'. The aims of the measurements were to quantify the vertical profiles of aerosols up to the altitude of 3.5 km, to study the new particle formation in the lower troposphere, to measure the planetary boundary layer evolution, and to support the measurements performed by Zeppelin NT. We used a Cessna 172 light aircraft as a platform. An aerosol and gas inlet was mounted under the right wing and the sample air was conducted inside the cabin where most of the instruments were placed. The aerosol measurement instruments included a TSI 3776 condensation particle counter (CPC) with a cut-off size of 3 nm, a Scanning Mobility Particle Sizer (SMPS), with a size range of 10-350 nm, and a Particle Size Magnifier (PSM) connected with a TSI 3772 condensation particle counter. As the properties of the PSM measuring in airborne conditions were still under testing during the campaign, the setups of the PSM varied between the measurements. Other instruments on board included a Li-Cor Li-840 H2O/Co2-analyzer, a temperature sensor, a relative humidity sensor, and a GPS receiver. Total amount of 45 flights with 118 flight hours were performed between 24th April and 15th June 2013. The majority of the flights were flown around SMEAR II station located in Hyytiälä, and when possible, the flights were synchronized with the Zeppelin flights. Simultaneously, an extensive field campaign to measure aerosol and gas properties was performed on-ground at SMEAR II station. A time series of airborne aerosol data of around 1.5 months allows us to construct statistical vertical profiles of aerosol size

  10. Measurements of the diffuse ultraviolet radiation

    NASA Technical Reports Server (NTRS)

    Fix, John D.; Craven, John D.; Frank, Louis A.

    1989-01-01

    The imaging instrumentation on the Dynamics Explorer 1 satellite has been used to measure the intensity of the diffuse ultraviolet radiation on two great circles about the sky. It is found that the isotropic component of the diffuse ultraviolet radiation (possibly of extragalactic origin) has an intensity of 530 + or - 80 units (a unit is 1 photon per sq cm s A sr) at a wavelength of 150 nm. The Galactic component of the diffuse ultraviolet radiation has a dependence on Galactic latitude which requires strongly forward scattering particles if it is produced by dust above the Galactic plane.

  11. Direction finding measurements of auroral kilometric radiation

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.; Baumback, M. M.; Gurnett, D. A.

    1974-01-01

    Direction finding measurements with plasma wave experiments onboard the Hawkeye-1 and IMP-8 satellites were used to locate the source region of auroral kilometric radiation. The radiation exhibits peak intensities between about 100 kHz and 300 kHz, and emits intense sporadic bursts lasting for between one half hour to several hours. The total power emitted in this frequency range exceeds 10 to the 9th power watts at peak intensity. The occurrence of the radiation is known to be closely associated with bright auroral arcs which occur in the local evening auroral regions.

  12. Methods of in vivo radiation measurement

    DOEpatents

    Huffman, Dennis D.; Hughes, Robert C.; Kelsey, Charles A.; Lane, Richard; Ricco, Antonio J.; Snelling, Jay B.; Zipperian, Thomas E.

    1990-01-01

    Methods of and apparatus for in vivo radiation measurements relay on a MOSFET dosimeter of high radiation sensitivity with operates in both the passive mode to provide an integrated dose detector and active mode to provide an irradiation rate detector. A compensating circuit with a matched unirradiated MOSFET is provided to operate at a current designed to eliminate temperature dependence of the device. Preferably, the MOSFET is rigidly mounted in the end of a miniature catheter and the catheter is implanted in the patient proximate the radiation source.

  13. Radiation Transmission Measurements for a Lightweight Fabric

    SciTech Connect

    Friedman, H; Singh, M S; DeMeo, R F

    2003-01-17

    Radiation Shield Technologies has developed a lightweight fabric, shown in Fig. 1, with radiation shielding properties for X ray, gamma ray and beta particle emissions in the range of energies relevant to clinical and Homeland Security applications. Detailed measurements were done to measure the shielding properties of this material against the spectra of standard radionuclides and x-ray generators. The mass attenuation coefficients were calculated using LLNL cross section data, a 3-D photon transport code, elemental weight fractions and the measured density of the fabric.

  14. MSL-RAD radiation environment measurements.

    PubMed

    Guo, Jingnan; Zeitlin, Cary; Wimmer-Schweingruber, Robert F; Hassler, Donald M; Ehresmann, Bent; Köhler, Jan; Böhm, Eckart; Böttcher, Stephan; Brinza, David; Burmeister, Sönke; Cucinotta, Francis; Martin, Cesar; Posner, Arik; Rafkin, Scot; Reitz, Guenther

    2015-09-01

    In this study, results are presented from the on-board radiation assessment detector (RAD) of Mars Science Laboratory (MSL). RAD is designed to measure the energetic particle radiation environment, which consists of galactic cosmic rays (GCRs) and solar energetic particles (SEPs) as well as secondary particles created by nuclear interactions of primary particles in the shielding (during cruise) or Martian soil and atmosphere (surface measurements). During the cruise, RAD collected data on space radiation from inside the craft, thus allowing for a reasonable estimation of what a human crew travelling to/from Mars might be exposed to. On the surface of Mars, RAD is shielded by the atmosphere (from above) and the planet itself (from below). RAD measures the first detailed radiation data from the surface of another planet, and they are highly relevant for planning future crewed missions. The results for radiation dose and dose equivalent (a quantity most directly related to human health risk) are presented during the cruise phase, as well as on the Martian surface. Dose and dose equivalent are dominated by the continuous GCR radiation, but several SEP events were also detected and are discussed here.

  15. Comparison of airborne and terrestrial gamma spectrometry measurements - evaluation of three areas in southern Sweden.

    PubMed

    Kock, Peder; Samuelsson, Christer

    2011-06-01

    The Geological Survey of Sweden (SGU) has been conducting airborne gamma spectrometry measurements of natural radioactivity in Sweden for more than 40 years. Today, the database covers about 80% of the country's land surface. This article explores the first step of putting this data into use in radioactive source search at ground level. However, in order to be able to use the airborne background measurements at ground level, SGU data must be validated against terrestrial data. In this work, we compare the SGU data with data measured by a portable backpack system. This is done for three different areas in southern Sweden. The statistical analysis shows that a linear relationship and a positive correlation exist between the air and ground data. However, this linear relationship could be revealed only when the region possessed large enough variations in areal activity. Furthermore, the activity distributions measured show good agreement to those of SGU. We conclude that the SGU database could be used for terrestrial background assessment, given that a linear transfer function is established.

  16. Distance measurement to high remote targets based on the airborne chaotic laser

    NASA Astrophysics Data System (ADS)

    Kou, Renke; Wang, Haiyan; Wu, Xueming

    2016-10-01

    According to the characteristics of chaotic laser, which has ability of novel anti-jamming, high bandwidth and detecting distance of the movement target to the millimeter precision, a modeling method of using airborne chaotic laser system to detect distance of high remote targets is proposed for the first time. The characteristics of chaotic laser and principle of interferometry distance were analyzed and the model of airborne chaotic laser ranging is established. Meanwhile, the influence of detection accuracy, which inducted by the main peak width of chaotic laser and the jamming signal is analyzed. According to the results of simulation analysis, we can get conclusions that the main factors of affecting the distance measurement are transmitted power, receiving sensitivity, and various losses of transmission medium. Autocorrelation characteristic of chaotic signal can also affect the dynamic range of the whole system. The main peak width of chaotic laser is the main factor of influencing the accuracy of measurement. However, the jamming signal affect distance measuring range and accuracy of measurement little. Finally, the model's effectiveness is proved by comparing the experience data and simulation data.

  17. Detailed Evaluation of MODIS Fire Radiative Power Measurements

    NASA Technical Reports Server (NTRS)

    Ichoku, Charles

    2010-01-01

    Satellite remote sensing is providing us tremendous opportunities to measure the fire radiative energy (FRE) release rate or power (FRP) from open biomass burning, which affects many vegetated regions of the world on a seasonal basis. Knowledge of the biomass burning characteristics and emission source strengths of different (particulate and gaseous) smoke constituents is one of the principal ingredients upon which the assessment, modeling, and forecasting of their distribution and impacts depend. This knowledge can be gained through accurate measurement of FRP, which has been shown to have a direct relationship with the rates of biomass consumption and emissions of major smoke constituents. Over the last decade or so, FRP has been routinely measured from space by both the MODIS sensors aboard the polar orbiting Terra and Aqua satellites, and the SEVIRI sensor aboard the Meteosat Second Generation (MSG) geostationary satellite. During the last few years, FRP has been gaining recognition as an important parameter for facilitating the development of various scientific studies relating to the quantitative characterization of biomass burning and their emissions. Therefore, we are conducting a detailed analysis of the FRP products from MODIS to characterize the uncertainties associated with them, such as those due to the MODIS bow-tie effects and other factors, in order to establish their error budget for use in scientific research and applications. In this presentation, we will show preliminary results of the MODIS FRP data analysis, including comparisons with airborne measurements.

  18. Laser measurement of extinction coefficients of highly absorbing liquids. [airborne oil spill monitoring application

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Kincaid, J. S.

    1980-01-01

    A coaxial dual-channel laser system has been developed for the measurement of extinction coefficients of highly absorbing liquids. An empty wedge-shaped sample cell is first translated laterally through a He-Ne laser beam to measure the differential thickness using interference fringes in reflection. The wedge cell is carefully filled with the oil sample and translated through the coaxially positioned dye laser beam for the differential attenuation or extinction measurement. Optional use of the instrumentation as a single-channel extinction measurement system and also as a refractometer is detailed. The system and calibration techniques were applied to the measurement of two crude oils whose extinction values were required to complete the analysis of airborne laser data gathered over four controlled spills.

  19. Measurements of ocean wave spectra and modulation transfer function with the airborne two frequency scatterometer

    NASA Technical Reports Server (NTRS)

    Weissman, D. E.; Johnson, J. W.

    1984-01-01

    The directional spectrum and the microwave modulation transfer function of ocean waves can be measured with the airborne two frequency scatterometer technique. Similar to tower based observations, the aircraft measurements of the Modulation Transfer Function (MTF) show that it is strongly affected by both wind speed and sea state. Also detected are small differences in the magnitudes of the MTF between downwind and upwind radar look directions, and variations with ocean wavenumber. The MTF inferred from the two frequency radar is larger than that measured using single frequency, wave orbital velocity techniques such as tower based radars or ROWS measurements from low altitude aircraft. Possible reasons for this are discussed. The ability to measure the ocean directional spectrum with the two frequency scatterometer, with supporting MTF data, is demonstrated.

  20. Measurement of backscattering from sea with an airborne radar at L band

    NASA Astrophysics Data System (ADS)

    Luo, Xianyun; Zhang, Zhongzhi; Yin, Zhiying; Sun, Fang; Kang, Shifeng; Wang, Laibu; Yu, Yunchao; Wen, Fangru

    1998-08-01

    Measurements of electromagnetic backscattering from sea surface at L band have been done with airborne side-looking radar system. Several flights are made for various sea states. Coherent radar data ta HH polarization and some truth data such as wave height, wind velocity and direction, temperature of sea water are recorded. Corner reflectors and active backscattering coefficient can be derived from the radar data and the cinematic data. The result presented in this paper include scattering coefficient and statistical analysis of radar echo with typical probability distribution functions such as Rayleigh, Weibull, Log-normal and K distribution.

  1. Airborne urban/suburban noise measurements at 121.5/243 MHz

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Hill, J. S.

    1977-01-01

    An airborne measurement of the terrestrial, radio-frequency (RF) noise environment over U.S. metropolitan urban/suburban areas has been made at the 121.5/243 MHz emergency-distress search and rescue (S&R) communications frequencies. Profile contour plots of antenna-noise temperature for U.S.A. East Coast and mid-west urban/suburban areas is presented for daytime/nighttime observations at 121.5/243 MHz. These plots are helpful for compiling radio-noise environment maps; in turn useful for designing satellite-aided, emergency-distress search and rescue communication systems.

  2. Initial airborne CO{sub 2} DIAL measurements: Discussion of results and data analysis considerations

    SciTech Connect

    Tiee, J.J.; Foy, B.R.; Quick, C.R.

    1997-07-01

    A detailed discussion of airborne CO{sub 2}, DIAL measurements obtained from the first joint N-ABLE field campaign at INEL is presented. System performance characteristics, including return signal strength, averaging statistics, and temporal correlation as well as multi-line DIAL spectral data are discussed. In particular, we review data acquisition and analysis strategies pertinent to chemical detection from a moving platform, such as range determination and correction, and return signal processing (waveform vs. box-car integration, baseline correction). We also report observed effects and variations due to near-field light scattering, pointing and tracking stability, and stack-release plume dynamics.

  3. Prediction and performance measures of atmospheric disturbances on an airborne imaging platform

    NASA Astrophysics Data System (ADS)

    Dayton, David C.; Gonglewski, John D.; Martin, Jeffrey B.; Kovacs, Mark A.; Cardani, Joseph C.; Maia, Francisco; Aflalo, Tyson; Shilko, Michael L., Sr.

    2004-02-01

    A series of airborne imaging experiments have been conducted on the island of Maui. The imaging platform was a Twin Otter aircraft, which circled ground target sites. The typical platform altitude was 3000 meters, with a slant range to the target of 9000 meters. This experiment was performed during the day using solar illuminated target buildings, and at night with spotlights used to simulate point sources. Imaging system performance predictions were calculated using standard atmospheric turbulence models, and aircraft boundary layer models. Several different measurement approaches were then used to estimate the actual system performance, and make comparisons with the calculations.

  4. 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

  5. Initial evaluation of airborne water vapour measurements by the IAGOS-GHG CRDS system

    NASA Astrophysics Data System (ADS)

    Filges, Annette; Gerbig, Christoph; Smit, Herman G. J.; Krämer, Martina; Spelten, Nicole

    2013-04-01

    Accurate and reliable airborne measurements of water vapour are still a challenge. Presently, no airborne humidity sensor exists that covers the entire range of water vapour content between the surface and the upper troposphere/lower stratosphere (UT/LS) region with sufficient accuracy and time resolution. Nevertheless , these data are a pre-requisite to study the underlying processes in the chemistry and physics of the atmosphere. The DENCHAR project (Development and Evaluation of Novel Compact Hygrometer for Airborne Research) addresses this deficit by developing and characterizing novel or improved compact airborne hygrometers for different airborne applications within EUFAR (European Facility for Airborne Research). As part of the DENCHAR inter-comparison campaign in Hohn (Germany), 23 May - 1 June 2011, a commercial gas analyzer (G2401-m, Picarro Inc.,US), based on cavity ring-down spectroscopy (CRDS), was installed on a Learjet to measure water vapour, CO2, CH4 and CO. The CRDS components are identical to those chosen for integration aboard commercial airliner within IAGOS (In-service Aircraft for a Global Observing System). Thus the campaign allowed for the initial assessment validation of the long-term IAGOS H2O measurements by CRDS against reference instruments with a long performance record (FISH, the Fast In-situ Stratospheric Hygrometer, and CR2 frostpoint hygrometer, both research centre Juelich). The inlet system, a one meter long 1/8" FEP-tube connected to a Rosemount TAT housing (model 102BX, deiced) installed on a window plate of the aircraft, was designed to eliminate sampling of larger aerosols, ice particles, and water droplets, and provides about 90% of ram-pressure. In combination with a lowered sample flow of 0.1 slpm (corresponding to a 4 second response time), this ensured a fully controlled sample pressure in the cavity of 140 torr throughout an aircraft altitude operating range up to 12.5 km without the need of an upstream sampling pump

  6. Airborne Sun photometer measurements of aerosol optical depth and columnar water vapor during the Puerto Rico Dust Experiment and comparison with land, aircraft, and satellite measurements

    NASA Astrophysics Data System (ADS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey S.; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Smirnov, Alexander; Dubovik, Oleg; Welton, Ellsworth J.; Campbell, James R.; Wang, Jun; Christopher, Sundar A.

    2003-10-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km above sea level (asl) reproduce the vertical structure measured by coincident aircraft in situ measurements of total aerosol number concentration. AATS-6 extinction retrievals also agree with corresponding values derived from ground-based lidar measurements for altitudes above the trade inversion. The spectral behavior of AOD within specific layers beneath the top of the aircraft profile is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt, with mean Ångström wavelength exponents of ˜0.20. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in situ measurements agree to within ˜4% (0.13 g/cm2). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low-altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004-0.030 with coincident data obtained with an AERONET Sun/sky radiometer located on Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by ˜21%. AATS-6 AOD values measured during low-altitude aircraft traverses over the ocean are compared with corresponding AOD values retrieved over water from upwelling radiance measurements by the Moderate-Resolution Imaging Spectroradiometer (MODIS), Total Ozone Mapping Spectrometer (TOMS), and GOES 8 Imager satellite sensors, with mixed results.

  7. 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.

  8. Modeling of mean radiant temperature based on comparison of airborne remote sensing data with surface measured data

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Cheng; Chen, Chih-Yu; Matzarakis, Andreas; Liu, Jin-King; Lin, Tzu-Ping

    2016-06-01

    Assessment of outdoor thermal comfort is becoming increasingly important due to the urban heat island effect, which strongly affects the urban thermal environment. The mean radiant temperature (Tmrt) quantifies the effect of the radiation environment on humans, but it can only be estimated based on influencing parameters and factors. Knowledge of Tmrt is important for quantifying the heat load on human beings, especially during heat waves. This study estimates Tmrt using several methods, which are based on climatic data from a traditional weather station, microscale ground surface measurements, land surface temperature (LST) and light detection and ranging (LIDAR) data measured using airborne devices. Analytical results reveal that the best means of estimating Tmrt combines information about LST and surface elevation information with meteorological data from the closest weather station. The application in this method can eliminate the inconvenience of executing a wide range ground surface measurement, the insufficient resolution of satellite data and the incomplete data of current urban built environments. This method can be used to map a whole city to identify hot spots, and can be contributed to understanding human biometeorological conditions quickly and accurately.

  9. Simultaneous Retrieval of Aerosol and Surface Optical Properties from Combined Airborne- and Ground-Based Direct and Diffuse Radiometric Measurements

    NASA Technical Reports Server (NTRS)

    Gatebe, C. K.; Dubovik, O.; King, M. D.; Sinyuk, A.

    2010-01-01

    This paper presents a new method for simultaneously retrieving aerosol and surface reflectance properties from combined airborne and ground-based direct and diffuse radiometric measurements. The method is based on the standard Aerosol Robotic Network (AERONET) method for retrieving aerosol size distribution, complex index of refraction, and single scattering albedo, but modified to retrieve aerosol properties in two layers, below and above the aircraft, and parameters on surface optical properties from combined datasets (Cloud Absorption Radiometer (CAR) and AERONET data). A key advantage of this method is the inversion of all available spectral and angular data at the same time, while accounting for the influence of noise in the inversion procedure using statistical optimization. The wide spectral (0.34-2.30 m) and angular range (180 ) of the CAR instrument, combined with observations from an AERONET sunphotometer, provide sufficient measurement constraints for characterizing aerosol and surface properties with minimal assumptions. The robustness of the method was tested on observations made during four different field campaigns: (a) the Southern African Regional Science Initiative 2000 over Mongu, Zambia, (b) the Intercontinental Transport Experiment-Phase B over Mexico City, Mexico (c) Cloud and Land Surface Interaction Campaign over the Atmospheric Radiation Measurement (ARM) Central Facility, Oklahoma, USA, and (d) the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) over Elson Lagoon in Barrow, Alaska, USA. The four areas are dominated by different surface characteristics and aerosol types, and therefore provide good test cases for the new inversion method.

  10. Lidar measurements of polar stratospheric clouds during the 1989 airborne Arctic stratospheric expedition

    NASA Technical Reports Server (NTRS)

    Ismail, Syed; Browell, Edward V.

    1991-01-01

    The Airborne Arctic Stratospheric Expedition (AASE) was conducted during January to February 1989 from the Sola Air Station, Norway. As part of this expedition, the NASA Langley Research Center's multiwavelength airborne lidar system was flown on the NASA Ames Research Center's DC-8 aircraft to measure ozone (O3) and aerosol profiles in the region of the polar vortex. The lidar system simultaneously transmitted laser beams at 1064, 603, 311, and 301.5 nm to measure atmospheric scattering, polarization and O3 profiles. Long range flights were made between Stavanger, Norway, and the North Pole, and between 40 deg W and 20 deg E meridians. Eleven flights were made, each flight lasting an average of 10 hours covering about 8000 km. Atmospheric scattering ratios, aerosol polarizations, and aerosol scattering ratio wavelength dependences were derived from the lidar measurements to altitudes above 27 km. The details of the aerosol scattering properties of lidar observations in the IR, VIS, and UV regions are presented along with correlations with the national meteorological Center's temperature profiles.

  11. The correlation and quantification of airborne spectroradiometer data to turbidity measurements at Lake Powell, Utah

    NASA Technical Reports Server (NTRS)

    Merry, C. J.

    1979-01-01

    A water sampling program was accomplished at Lake Powell, Utah, during June 1975 for correlation to multispectral data obtained with a 500-channel airborne spectroradiometer. Field measurements were taken of percentage of light transmittance, surface temperature, pH and Secchi disk depth. Percentage of light transmittance was also measured in the laboratory for the water samples. Analyses of electron micrographs and suspended sediment concentration data for four water samples located at Hite Bridge, Mile 168, Mile 150 and Bullfrog Bay indicated differences in the composition and concentration of the particulate matter. Airborne spectroradiometer multispectral data were analyzed for the four sampling locations. The results showed that: (1) as the percentage of light transmittance of the water samples decreased, the reflected radiance increased; and (2) as the suspended sediment concentration (mg/l) increased, the reflected radiance increased in the 1-80 mg/l range. In conclusion, valuable qualitative information was obtained on surface turbidity for the Lake Powell water spectra. Also, the reflected radiance measured at a wavelength of 0.58 micron was directly correlated to the suspended sediment concentration.

  12. Analysis of Airborne Radar Altimetry Measurements of the Greenland Ice Sheet

    NASA Technical Reports Server (NTRS)

    Ferraro, Ellen J.

    1994-01-01

    This dissertation presents an analysis of airborne altimetry measurements taken over the Greenland ice sheet with the 13.9 GHz Advanced Application Flight Experiment (AAFE) pulse compression radar altimeter. This Ku-band instrument was refurbished in 1990 by the Microwave Remote Sensing Laboratory at the University of Massachusetts to obtain high-resolution altitude measurements and to improve the tracking, speed, storage and display capabilities of the radar. In 1991 and 1993, the AAFE altimeter took part in the NASA Multisensor Airborne Altimetry Experiments over Greenland, along with two NASA laser altimeters. Altitude results from both experiments are presented along with comparisons to the laser altimeter and calibration passes over the Sondrestroem runway in Greenland. Although it is too early to make a conclusion about the growth or decay of the ice sheet, these results show that the instrument is capable of measuring small-scale surface changes to within 14 centimeters. In addition, results from these experiments reveal that the radar is sensitive to the different diagenetic regions of the ice sheet. Return waveforms from the wet- snow, percolation and dry-snow zones show varying effects of both surface scattering and sub-surface or volume scattering. Models of each of the diagenetic regions of Greenland are presented along with parameters such as rms surface roughness, rms surface slope and attenuation coefficient of the snow pack obtained by fitting the models to actual return waveforms.

  13. Aerosol classification using airborne High Spectral Resolution Lidar measurements - methodology and examples

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

    The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 aircraft has acquired extensive datasets of aerosol extinction (532 nm), aerosol optical depth (AOD) (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) profiles during 18 field missions that have been conducted over North America since 2006. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, backscatter color ratio, and spectral depolarization ratio) are shown to vary with location and aerosol type. A methodology based on observations of known aerosol types is used to qualitatively classify the extensive set of HSRL aerosol measurements into eight separate types. Several examples are presented showing how the aerosol intensive parameters vary with aerosol type and how these aerosols are classified according to this new methodology. The HSRL-based classification reveals vertical variability of aerosol types during the NASA ARCTAS field experiment conducted over Alaska and northwest Canada during 2008. In two examples derived from flights conducted during ARCTAS, the HSRL classification of biomass burning smoke is shown to be consistent with aerosol types derived from coincident airborne in situ measurements of particle size and composition. The HSRL retrievals of AOD and inferences of aerosol types are used to apportion AOD to aerosol type; results of this analysis are shown for several experiments.

  14. Aerosol classification using airborne High Spectral Resolution Lidar measurements - methodology and examples

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

    The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 aircraft has acquired extensive datasets of aerosol extinction (532 nm), aerosol optical thickness (AOT) (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm) profiles during 18 field missions that have been conducted over North America since 2006. The lidar measurements of aerosol intensive parameters (lidar ratio, depolarization, backscatter color ratio, and spectral depolarization ratio) are shown to vary with location and aerosol type. A methodology based on observations of known aerosol types is used to qualitatively classify the extensive set of HSRL aerosol measurements into eight separate types. Several examples are presented showing how the aerosol intensive parameters vary with aerosol type and how these aerosols are classified according to this new methodology. The HSRL-based classification reveals vertical variability of aerosol types during the NASA ARCTAS field experiment conducted over Alaska and northwest Canada during 2008. In two examples derived from flights conducted during ARCTAS, the HSRL classification of biomass burning smoke is shown to be consistent with aerosol types derived from coincident airborne in situ measurements of particle size and composition. The HSRL retrievals of AOT and inferences of aerosol types are used to apportion AOT to aerosol type; results of this analysis are shown for several experiments.

  15. Overview and Initial Results from the DEEPWAVE Airborne and Ground-Based Measurement Program

    NASA Astrophysics Data System (ADS)

    Fritts, D. C.

    2015-12-01

    The deep-propagating gravity wave experiment (DEEPWAVE) was performed on and over New Zealand, the Tasman Sea, and the Southern Ocean with core airborne measurements extending from 5 June to 21 July 2014 and supporting ground-based measurements spanning a longer interval. The NSF/NCAR GV employed standard flight-level measurements and new airborne lidar and imaging measurements of gravity waves (GWs) from sources at lower altitudes throughout the stratosphere and into the mesosphere and lower thermosphere (MLT). The new GV lidars included a Rayleigh lidar measuring atmospheric density and temperature from ~20-60 km and a sodium resonance lidar measuring sodium density and temperature at ~75-105 km. An airborne Advanced Mesosphere Temperature Mapper (AMTM) and two IR "wing" cameras imaged the OH airglow temperature and/or intensity fields extending ~900 km across the GV flight track. The DLR Falcon was equipped with its standard flight-level instruments and an aerosol Doppler lidar measuring radial winds below the Falcon. DEEPWAVE also included extensive ground-based measurements in New Zealand, Tasmania, and Southern Ocean Islands. DEEPWAVE performed 26 GV flights and 13 Falcon flights, and ground-based measurements occurred whether or not the aircraft were flying. Collectively, many diverse cases of GW forcing, propagation, refraction, and dissipation spanning altitudes of 0-100 km were observed. Examples include strong mountain wave (MW) forcing and breaking in the lower and middle stratosphere, weak MW forcing yielding MW penetration into the MLT having very large amplitudes and momentum fluxes, MW scales at higher altitudes ranging from ~10-250 km, large-scale trailing waves from orography refracting into the polar vortex and extending to high altitudes, GW generation by deep convection, large-scale GWs arising from jet stream sources, and strong MWs in the MLT arising from strong surface flow over a small island. DEEPWAVE yielded a number of surprises, among

  16. Gamma radiation background measurements from Spacelab 2

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.; Gregory, John C.; Fishman, Gerald J.

    1988-01-01

    A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, Earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

  17. GTD analysis of airborne antennas radiating in the presence of lossy dielectric layers

    NASA Technical Reports Server (NTRS)

    Rojas-Teran, R. G.; Burnside, W. D.

    1981-01-01

    The patterns of monopole or aperture antennas mounted on a perfectly conducting convex surface radiating in the presence of a dielectric or metal plate are computed. The geometrical theory of diffraction is used to analyze the radiating system and extended here to include diffraction by flat dielectric slabs. Modified edge diffraction coefficients valid for wedges whose walls are lossy or lossless thin dielectric or perfectly conducting plates are developed. The width of the dielectric plates cannot exceed a quarter of a wavelength in free space, and the interior angle of the wedge is assumed to be close to 0 deg or 180 deg. Systematic methods for computing the individual components of the total high frequency field are discussed. The accuracy of the solutions is demonstrated by comparisons with measured results, where a 2 lambda by 4 lambda prolate spheroid is used as the convex surface. A jump or kink appears in the calculated pattern when higher order terms that are important are not included in the final solution. The most immediate application of the results presented here is in the modelling of structures such as aircraft which are composed of nonmetallic parts that play a significant role in the pattern.

  18. Radioactive effluent measurements at the Army Pulse Radiation Facility

    SciTech Connect

    Scherpelz, R.I.; Glissmeyer, J.A.

    1994-11-01

    Staff from the Pacific Northwest Laboratory (PNL) performed measurements of the radioactive effluents emitted by the Army Pulse Radiation Facility (APRF). These measurements were performed by collecting the cooling air that passed by the APRF reactor as it operated, passing the air through filters to collect the particulates and iodines, and collecting samples of the air to be analyzed for noble gases. The reactor operated for four test runs, including two pulses and two steady state runs. After each reactor run, the filters were counted using gamma spectrometry to identify the nuclides and to determine the activity of nuclides deposited on the filters. The study provided radionuclide release fraction data that can be used to estimate the airborne emissions resulting from APRF operations. The release fraction for particulate fission products and radioiodines, as derived from these measurements, was found to be 8.9 {times} 10{sup {minus}6} for reactor pulses and 4.3 {times} 10{sup {minus}6} for steady state operation. These values compare to a theoretical value of 1.5 {times} 10{sup {minus}5}.

  19. Measurement of Global Radiation using Photovoltaic Panels

    NASA Astrophysics Data System (ADS)

    Veroustraete, Frank; Bronders, Jan; Lefevre, Filip; Mensink, Clemens

    2014-05-01

    The Vito Unit - Environmental and Spatial Aspects (RMA) - for many of its models makes use of global solar radiation. From this viewpoint and also from the notion that this variable is seldom measured or available at the local scale and at high multi-temporal frequencies, it can be stated that many models are fed with low quality estimates of global solar radiation at the local to regional scales. A project was initiated called SUNSPIDER with the following objective. To make use of photovoltaic solar panels to measure solar radiation at the highest spatio-temporal resolution, from the local to the regional scales and from minutes to years. To integrate the measured solar fields in different application fields like, plant systems and agriculture, agro-meteorology and hydrology and last but not least solar energy applications. In Belgium about 250.000 PV installations have been built leading to about 6% electric power supply from photovoltaics on a yearly basis. Last year in June, the supply reached a peak of more than 20% of the total power input on the Belgian grid. A database of Belgian residential solar panel sites will be compiled. The database will serve as an input to an inverted PV model to be able to perform radiation calculations specifically for each of the validated panel sites based on minutely logged power data. Data acquisition for these sites will start each time a site is validated and hence imported in the database. Keywords: Photovoltaic Panels; PV modelling; Global Radiation.

  20. MEASUREMENT AND ANALYSIS OF CIRCUMSOLAR RADIATION

    SciTech Connect

    Grether, Donald; Evans, David; Hunt, Arlon; Wahlig, Michael

    1980-10-01

    The purpose of this project is to provide measurements and analyses of the solar and circumsolar radiation for application to solar energy systems that employ lenses or mirrors to concentrate the incident sunlight. Circumsolar radiation results from the scattering of direct sunlight through small angles by atmospheric aerosols (e.g., dust, water-droplets or ice crystals in thin clouds). Concentrating solar energy systems will typically collect all of the direct solar radiation (that originating from the disk of the sun) plus some fraction of the circumsolar radiation. The exact fraction depends upon many factors, but primarily upon the angular size (field-of-view) of the receiver. A knowledge of the circumsolar radiation is then one factor in predicting or evaluating the performance of concentrating systems. The project employs unique instrument systems (called Circumsolar Telescopes) that were designed and fabricated at LBL. The basic measurements are (1) the "circumsolar scan", the brightness of the sun and circumsolar region as a function of angular distance from the center of the sun and (2) the usual "normal incidence" measurement of a pyrheliometer. Both measurements are made for the entire solar spectrum, and (via colored filters) for eight essentially contiguous wavelength bands. Thus the measurements are applicable to systems in which the receiver is essentially wavelength-insensitive (e.g., central receiver) and to wavelength-sensitive systems (e.g., concentrating photovoltaics). A secondary purpose of the project is to relate the data to the atmospheric processes that attenuate the solar radiation available to terrestrial solar energy systems.

  1. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Water Vapor in ACE-Asia and Their Comparisons to Correlative Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Redemann, J.; Livingston, J.; Russell, P.; Hegg, D.; Wang, J.; Kahn, R.; Hsu, C.; Masonis, S.; Murayama, T.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    In the Spring 2001 phase of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia), the 6-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) operated on 15 of the 19 research flights of the NCAR C-130, while its 14-channel counterpart (AATS-14) flew successfully on all 19 research flights of the CIRPAS Twin Otter. ACE-Asia studied aerosol outflow from the Asian continent to the Pacific basin. It was designed to integrate suborbital and satellite measurements and models to reduce the uncertainty in calculations of the climate forcing due to aerosols. AATS-6 and AATS-14 measured solar beam transmission at six and 14 wavelengths (380-1021 and 354-1558 nm, respectively), yielding aerosol optical depth (AOD) spectra and columnar water vapor (CWV). Vertical differentiation in profiles yielded aerosol extinction spectra and water vapor concentration. In this paper, we plan to present examples of the following, preliminary findings that are based in part on our airborne sunphotometer measurements: (1) The wavelength dependence of sunphotometer-derived AOD and extinction indicates that supermicron dust was often a major component of the aerosol, frequently extending to high altitudes. The percentage of full-column AOD (525 nm) that Jay above 3 km was typically 34+/-13%. In contrast, the analogous percentage of columnar water vapor was only 10+/-4%; (2) Initial comparison studies between AOD data obtained by AATS-6 and AATS-14 during coordinated low-level flight legs show agreement well within the instruments' error bars; (3) Aerosol extinction has been derived from airborne in situ measurements of scattering (nephelometers) and absorption (particle soot/ absorption photometer, PSAP) or calculated from particle size distribution measurements (mobility analyzers and aerodynamic particle sizers). Comparison with corresponding extinction values derived from the Ames airborne sunphotometer measurements shows good agreement for the vertical distribution

  2. Radiation measurements from polar and geosynchronous satellites

    NASA Technical Reports Server (NTRS)

    Vonderhaar, T. H.

    1973-01-01

    During the 1960's, radiation budget measurements from satellites have allowed quantitative study of the global energetics of our atmosphere-ocean system. A continuing program is planned, including independent measurement of the solar constant. Thus far, the measurements returned from two basically different types of satellite experiments are in agreement on the long term global scales where they are most comparable. This fact, together with independent estimates of the accuracy of measurement from each system, shows that the energy exchange between earth and space is now measured better than it can be calculated. Examples of application of the radiation budget data were shown. They can be related to the age-old problem of climate change, to the basic question of the thermal forcing of our circulation systems, and to the contemporary problems of local area energetics and computer modeling of the atmosphere.

  3. A new method to measure air-borne pyrogens based on human whole blood cytokine response.

    PubMed

    Kindinger, Ilona; Daneshian, Mardas; Baur, Hans; Gabrio, Thomas; Hofmann, Andreas; Fennrich, Stefan; von Aulock, Sonja; Hartung, Thomas

    2005-03-01

    Air-borne microorganisms, as well as their fragments and components, are increasingly recognized to be associated with pulmonary diseases, e.g. organic dust toxic syndrome, humidifier lung, building-related illness, "Monday sickness." We have previously described and validated a new method for the detection of pyrogenic (fever-inducing) microbial contaminations in injectable drugs, based on the inflammatory reaction of human blood to pyrogens. We have now adapted this test to evaluate the total inflammatory capacity of air samples. Air was drawn onto PTFE membrane filters, which were incubated with human whole blood from healthy volunteers inside the collection device. Cytokine release was measured by ELISA. The test detects endotoxins and non-endotoxins, such as fungal spores, Gram-positive bacteria and their lipoteichoic acid moiety and pyrogenic dust particles with high sensitivity, thus reflecting the total inflammatory capacity of a sample. When air from different surroundings such as working environments and animal housing was assayed, the method yielded reproducible data which correlated with other parameters of microbial burden tested. We further developed a standard material for quantification and showed that this assay can be performed with cryopreserved as well as fresh blood. The method offers a test to measure the integral inflammatory capacity of air-borne microbial contaminations relevant to humans. It could thus be employed to assess air quality in different living and work environments.

  4. Airborne lidar for simultaneous measurement of column CO2 and water vapor in the atmosphere

    NASA Astrophysics Data System (ADS)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Antill, Charles W.; Remus, Ruben; Yu, Jirong

    2016-10-01

    The 2-micron wavelength region is suitable for atmospheric carbon dioxide (CO2) measurements due to the existence of distinct absorption feathers for the gas at this particular wavelength. For more than 20 years, researchers at NASA Langley Research Center (LaRC) have developed several high-energy and high repetition rate 2-micron pulsed lasers. This paper will provide status and details of an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar. The development of this active optical remote sensing IPDA instrument is targeted for measuring both CO2 and water vapor (H2O) in the atmosphere from an airborne platform. This presentation will focus on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver telescope, detection system and data acquisition. Future plans for the IPDA lidar system for ground integration, testing and flight validation will also be presented.

  5. Airborne Lidar for Simultaneous Measurement of Column CO2 and Water Vapor in the Atmosphere

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Petros, Mulugeta; Refaat, Tamer F.; Antill, Charles W.; Remus, Ruben; Yu, Jirong

    2016-01-01

    The 2-micron wavelength region is suitable for atmospheric carbon dioxide (CO2) measurements due to the existence of distinct absorption feathers for the gas at this particular wavelength. For more than 20 years, researchers at NASA Langley Research Center (LaRC) have developed several high-energy and high repetition rate 2-micron pulsed lasers. This paper will provide status and details of an airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar. The development of this active optical remote sensing IPDA instrument is targeted for measuring both CO2 and water vapor (H2O) in the atmosphere from an airborne platform. This presentation will focus on the advancement of the 2-micron triple-pulse IPDA lidar development. Updates on the state-of-the-art triple-pulse laser transmitter will be presented including the status of seed laser locking, wavelength control, receiver telescope, detection system and data acquisition. Future plans for the IPDA lidar system for ground integration, testing and flight validation will also be presented.

  6. Airborne methane remote measurements reveal heavy-tail flux distribution in Four Corners region

    PubMed Central

    Thorpe, Andrew K.; Thompson, David R.; Hulley, Glynn; Kort, Eric Adam; Vance, Nick; Borchardt, Jakob; Krings, Thomas; Gerilowski, Konstantin; Sweeney, Colm; Conley, Stephen; Bue, Brian D.; Aubrey, Andrew D.; Hook, Simon; Green, Robert O.

    2016-01-01

    Methane (CH4) impacts climate as the second strongest anthropogenic greenhouse gas and air quality by influencing tropospheric ozone levels. Space-based observations have identified the Four Corners region in the Southwest United States as an area of large CH4 enhancements. We conducted an airborne campaign in Four Corners during April 2015 with the next-generation Airborne Visible/Infrared Imaging Spectrometer (near-infrared) and Hyperspectral Thermal Emission Spectrometer (thermal infrared) imaging spectrometers to better understand the source of methane by measuring methane plumes at 1- to 3-m spatial resolution. Our analysis detected more than 250 individual methane plumes from fossil fuel harvesting, processing, and distributing infrastructures, spanning an emission range from the detection limit ∼ 2 kg/h to 5 kg/h through ∼ 5,000 kg/h. Observed sources include gas processing facilities, storage tanks, pipeline leaks, and well pads, as well as a coal mine venting shaft. Overall, plume enhancements and inferred fluxes follow a lognormal distribution, with the top 10% emitters contributing 49 to 66% to the inferred total point source flux of 0.23 Tg/y to 0.39 Tg/y. With the observed confirmation of a lognormal emission distribution, this airborne observing strategy and its ability to locate previously unknown point sources in real time provides an efficient and effective method to identify and mitigate major emissions contributors over a wide geographic area. With improved instrumentation, this capability scales to spaceborne applications [Thompson DR, et al. (2016) Geophys Res Lett 43(12):6571–6578]. Further illustration of this potential is demonstrated with two detected, confirmed, and repaired pipeline leaks during the campaign. PMID:27528660

  7. Ground truth measurement for the analysis of airborne SAR data recorded over Oberpfaffenhofen, FRG, 1989

    NASA Technical Reports Server (NTRS)

    Bayer, T.; Wieneke, F.; Winter, R.

    1990-01-01

    As a preliminary investigation to the joint multiparameter SIR-C/X-SAR shuttle experiment of NASA/JPL (USA), DLR (FRG), and PSN (Italy) which is scheduled for the year 1992 an airborne SAR campaign was conducted over Oberpfaffenhofen, FRG, in August 1989. Primarily this campaign was planned to test and verify equipment and algorithms developed at the DLR to calibrate multifrequency polarimetric SAR data. Oberpfaffenhofen is designated as one of the super test sites for the SIR-C/X-SAR experiment which will be imaged under all circumstances except severe mission errors. A super test site drives radar parameters and look directions and the recorded SAR data will be calibrated. In addition ancillary data will be available for the site. During the airborne STAR campaign conducted in the week of August 14th 1989 various sensor types were used to record remote sensing data over the calibration test site and its vicinity: the polarimetric DC-8 JPL-SAR (P-, L-, C-band), the DLR airborne SAR (C-, X-band), color infrared aerial photography (DLR), and the truck-mounted scatterometer (C- and X-band) of the Institute for Navigation, University of Stuttgart (INS). Because of this variety of different sensor types used and out of the fact that sufficiently large forested and agriculturally used areas were planned to be covered by these sensors, the interest of several German research groups involved in investigations concerning SAR land applications arose. The following groups carried out different ground-truth measurements: University of Bonn, Institute for plant cultivation (plant morphology and moisture content); University of Braunschweig, Institute for Geography (soil moisture and surface roughness); University of Freiburg, Institute for Geography (dielectric soil properties, landuse); and University of Munich, Institute for Geography (landuse inventory, plant, surface, and soil parameters). This paper presents the joint ground truth activities of the Institute for Geography

  8. Airborne methane remote measurements reveal heavy-tail flux distribution in Four Corners region.

    PubMed

    Frankenberg, Christian; Thorpe, Andrew K; Thompson, David R; Hulley, Glynn; Kort, Eric Adam; Vance, Nick; Borchardt, Jakob; Krings, Thomas; Gerilowski, Konstantin; Sweeney, Colm; Conley, Stephen; Bue, Brian D; Aubrey, Andrew D; Hook, Simon; Green, Robert O

    2016-08-30

    Methane (CH4) impacts climate as the second strongest anthropogenic greenhouse gas and air quality by influencing tropospheric ozone levels. Space-based observations have identified the Four Corners region in the Southwest United States as an area of large CH4 enhancements. We conducted an airborne campaign in Four Corners during April 2015 with the next-generation Airborne Visible/Infrared Imaging Spectrometer (near-infrared) and Hyperspectral Thermal Emission Spectrometer (thermal infrared) imaging spectrometers to better understand the source of methane by measuring methane plumes at 1- to 3-m spatial resolution. Our analysis detected more than 250 individual methane plumes from fossil fuel harvesting, processing, and distributing infrastructures, spanning an emission range from the detection limit [Formula: see text] 2 kg/h to 5 kg/h through [Formula: see text] 5,000 kg/h. Observed sources include gas processing facilities, storage tanks, pipeline leaks, and well pads, as well as a coal mine venting shaft. Overall, plume enhancements and inferred fluxes follow a lognormal distribution, with the top 10% emitters contributing 49 to 66% to the inferred total point source flux of 0.23 Tg/y to 0.39 Tg/y. With the observed confirmation of a lognormal emission distribution, this airborne observing strategy and its ability to locate previously unknown point sources in real time provides an efficient and effective method to identify and mitigate major emissions contributors over a wide geographic area. With improved instrumentation, this capability scales to spaceborne applications [Thompson DR, et al. (2016) Geophys Res Lett 43(12):6571-6578]. Further illustration of this potential is demonstrated with two detected, confirmed, and repaired pipeline leaks during the campaign.

  9. Airborne Lidar Measurements of Atmospheric Pressure Made Using the Oxygen A-Band

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Rodriquez, Michael D.; Allan, Graham R.; Hasselbrack, William E.; Mao, Jianping; Stephen, Mark A.; Abshire, James B.

    2012-01-01

    Accurate measurements of greenhouse gas mixing ratios on a global scale are currently needed to gain a better understanding of climate change and its possible impact on our planet. In order to remotely measure greenhouse gas concentrations in the atmosphere with regard to dry air, the air number density in the atmosphere is also needed in deriving the greenhouse gas concentrations. Since oxygen is stable and uniformly mixed in the atmosphere at 20.95%, the measurement of an oxygen absorption in the atmosphere can be used to infer the dry air density and used to calculate the dry air mixing ratio of a greenhouse gas, such as carbon dioxide or methane. OUT technique of measuring Oxygen uses integrated path differential absorption (IPDA) with an Erbium Doped Fiber Amplifier (EDF A) laser system and single photon counting module (SPCM). It measures the absorbance of several on- and off-line wavelengths tuned to an O2 absorption line in the A-band at 764.7 nm. The choice of wavelengths allows us to maximize the pressure sensitivity using the trough between two absorptions in the Oxygen A-band. Our retrieval algorithm uses ancillary meteorological and aircraft altitude information to fit the experimentally obtained lidar O2 line shapes to a model atmosphere and derives the pressure from the profiles of the two lines. We have demonstrated O2 measurements from the ground and from an airborne platform. In this paper we will report on our airborne measurements during our 2011 campaign for the ASCENDS program.

  10. Airborne CO2 and H2S Measurements at Hot Spring Basin, Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    McGee, K. A.; Doukas, M. P.; Werner, C. A.

    2007-12-01

    Gas emission-rate measurements at thermal areas located in remote regions with difficult ground access and little topographic relief pose a special challenge to those attempting to assess volcanic hazards in those areas. Several attempts have been made to measure gas emission rates from geyser basins, thermal areas and discrete large fumaroles at Yellowstone National Park through the use of fixed-wing aircraft with an on-board measurement system similar to that employed elsewhere at large stratovolcanoes. Despite minimum flight elevation restrictions and relatively flat terrain that often make access to the lowest margins of the plume difficult in these areas, we have successfully measured plumes of CO2 and H2S at several such areas and features at Yellowstone. We report here the results of a series of airborne measurements on 7 Jun 2006 at Hot Spring Basin (HSB), a remote vapor-dominated hydrothermal system just outside the northeast margin of Yellowstone caldera containing multiple gas vents. Using a LI-COR infrared spectrometer and Interscan electrochemical detector system, we detected a 3-km-wide plume approximately 2 km downwind from HSB. Several airborne traverses through a vertical slice of the plume allowed us to construct a cross-section of the plume and yielded emission rates of 170 metric tonnes per day (t/d) for CO2 and 2 t/d for H2S, similar to rates measured at Mt. Baker, WA (USA) in September 2000. However, an August 2006 ground-based study of emissions from HSB yielded higher emission rates for both CO2 and H2S (Werner et al., this session), suggesting that not all of the diffuse emissions are reflected in the airborne measurement. Although a complete inventory of plume emission rates from the majority of degassing sources in Yellowstone National Park is not yet complete, HSB appears to be a smaller gas emitter than some of the other sources in the Park (e.g., Norris Geyser Basin, Brimstone Basin, Mud Volcano, Grand Prismatic Spring and Mammoth Hot

  11. Studying the influence of temperature and pressure on microphysical properties of mixed-phase clouds using airborne measurements

    NASA Astrophysics Data System (ADS)

    Andreea, Boscornea; Sabina, Stefan; Sorin-Nicolae, Vajaiac; Mihai, Cimpuieru

    2015-04-01

    One cloud type for which the formation and evolution process is not well-understood is the mixed-phase type. In general mixed-phase clouds consist of liquid droplets and ice crystals. The temperature interval within both liquid droplets and ice crystals can potentially coexist is limited to 0 °C and - 40 °C. Mixed-phase clouds account for 20% to 30% of the global cloud coverage. The need to understand the microphysical characteristics of mixed-phase clouds to improve numerical forecast modeling and radiative transfer calculation is of major interest in the atmospheric community. In the past, studies of cloud phase composition have been significantly limited by a lack of aircraft instruments capable of discriminating between the ice and liquid phase for a wide range of particle sizes. Presently, in situ airborne measurements provide the most accurate information about cloud microphysical characteristics. This information can be used for verification of both numerical models and cloud remote-sensing techniques. The knowledge of the temperature and pressure variation during the airborne measurements is crucial in order to understand their influence on the cloud dynamics and also their role in the cloud formation processes like accretion and coalescence. Therefore, in this paper is presented a comprehensive study of cloud microphysical properties in mixed-phase clouds in focus of the influence of temperature and pressure variation on both, cloud dynamics and the cloud formation processes, using measurements performed with the ATMOSLAB - Airborne Laboratory for Environmental Atmospheric Research in property of the National Institute for Aerospace Research "Elie Carafoli" (INCAS). The airborne laboratory equipped for special research missions is based on a Hawker Beechcraft - King Air C90 GTx aircraft and is equipped with a sensors system CAPS - Cloud, Aerosol and Precipitation Spectrometer (30 bins, 0.51-50 µm) and a HAWKEYE cloud probe. The analyzed data in this

  12. On error sources during airborne measurements of the ambient electric field

    NASA Technical Reports Server (NTRS)

    Evteev, B. F.

    1991-01-01

    The principal sources of errors during airborne measurements of the ambient electric field and charge are addressed. Results of their analysis are presented for critical survey. It is demonstrated that the volume electric charge has to be accounted for during such measurements, that charge being generated at the airframe and wing surface by droplets of clouds and precipitation colliding with the aircraft. The local effect of that space charge depends on the flight regime (air speed, altitude, particle size, and cloud elevation). Such a dependence is displayed in the relation between the collector conductivity of the aircraft discharging circuit - on one hand, and the sum of all the residual conductivities contributing to aircraft discharge - on the other. Arguments are given in favor of variability in the aircraft electric capacitance. Techniques are suggested for measuring from factors to describe the aircraft charge.

  13. Double-Pulse Two-micron LPDA Lidar Simulation for Airborne Carbon Dioxide Measurements

    NASA Astrophysics Data System (ADS)

    Refaat, Tamer F.; Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta

    2016-06-01

    An advanced double-pulse 2-μm integrated path differential absorption lidar has been developed at NASA Langley Research Center for measuring atmospheric carbon dioxide. The instrument utilizes a state-of-the-art 2-μm laser transmitter with tunable on-line wavelength and advanced receiver. Instrument modeling and airborne simulations are presented in this paper. Focusing on random errors, results demonstrate instrument capabilities of performing precise carbon dioxide differential optical depth measurement with less than 3% random error for single-shot operation up to 11 km altitude. This study is useful for defining CO2 measurement weighting function for adaptive targeting, instrument setting, validation and sensitivity trade-offs.

  14. ARM-ACME V: ARM Airborne Carbon Measurements V on the North Slope of Alaska Field Campaign Report

    SciTech Connect

    Biraud, Sebastien C

    2016-05-01

    Atmospheric temperatures are warming faster in the Arctic than predicted by climate models. The impact of this warming on permafrost degradation is not well understood, but it is projected to increase carbon decomposition and greenhouse gas production (CO2 and/or CH4) by arctic ecosystems. Airborne observations of atmospheric trace gases, aerosols and cloud properties in North Slopes of Alaska (NSA) are improving our understanding of global climate, with the goal of reducing the uncertainty in global and regional climate simulations and projections. From June 1 through September 15, 2015, AAF deployed the G1 research aircraft and flew over the North Slope of Alaska (38 flights, 140 science flight hours), with occasional vertical profiling over Prudhoe Bay, Oliktok point, Barrow, Atqasuk, Ivotuk, and Toolik Lake. The aircraft payload included Picarro and Los Gatos Research (LGR) analyzers for continuous measurements of CO2, CH4, H2O, and CO and N2O mixing ratios, and a 12-flask sampler for analysis of carbon cycle gases (CO2, CO, CH4, N2O, 13CO2, and trace hydrocarbon species). The aircraft payload also include measurements of aerosol properties (number size distribution, total number concentration, absorption, and scattering), cloud properties (droplet and ice size information), atmospheric thermodynamic state, and solar/infrared radiation.

  15. Wedge immersed thermistor bolometer measures infrared radiation

    NASA Technical Reports Server (NTRS)

    Dreyfus, M. G.

    1965-01-01

    Wedge immersed-thermistor bolometer measures infrared radiation in the atmosphere. The thermistor flakes are immersed by optical contact on a wedge-shaped germanium lens whose narrow dimension is clamped between two complementary wedge-shaped germanium blocks bonded with a suitable adhesive.

  16. A new diagnostic method for separating airborne and structureborne noise radiated by plates with applications for propeller driven aircraft

    NASA Technical Reports Server (NTRS)

    Mcgary, Michael C.

    1988-01-01

    The anticipated application of advanced turboprop propulsion systems is expected to increase the interior noise of future aircraft to unacceptably high levels. The absence of technically and economically feasible noise source-path diagnostic tools has been a prime obstacle in the development of efficient noise control treatments for propeller-driven aircraft. A new diagnostic method that permits the separation and prediction of the fully coherent airborne and structureborne components of the sound radiated by plates or thin shells has been developed. Analytical and experimental studies of the proposed method were performed on an aluminum plate. The results of the study indicate that the proposed method could be used in flight, and has fewer encumbrances than the other diagnostic tools currently available.

  17. Measurements of Ocean Surface Scattering Using an Airborne 94-GHz Cloud Radar: Implication for Calibration of Airborne and Spaceborne W-band Radars

    NASA Technical Reports Server (NTRS)

    Li, Li-Hua; Heymsfield, Gerald M.; Tian, Lin; Racette, Paul E.

    2004-01-01

    Scattering properties of the Ocean surface have been widely used as a calibration reference for airborne and spaceborne microwave sensors. However, at millimeter-wave frequencies, the ocean surface backscattering mechanism is still not well understood, in part, due to the lack of experimental measurements. During the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE), measurements of ocean surface backscattering were made using a 94-GHz (W-band) cloud radar onboard a NASA ER-2 high-altitude aircraft. The measurement set includes the normalized Ocean surface cross section over a range of the incidence angles under a variety of wind conditions. Analysis of the radar measurements shows good agreement with a quasi-specular scattering model. This unprecedented dataset enhances our knowledge about the Ocean surface scattering mechanism at 94 GHz. The results of this work support the proposition of using the Ocean surface as a calibration reference for airborne millimeter-wave cloud radars and for the ongoing NASA CloudSat mission, which will use a 94-GHz spaceborne cloud radar for global cloud measurements.

  18. METHOD AND APPARATUS FOR MEASURING RADIATION

    DOEpatents

    Reeder, S.D.

    1962-04-17

    A chemical dosimeter for measuring the progress of a radiation-induced oxidation-reduction reaction is described. The dosimeter comprises a container filled with an aqueous chemical oxidation-reduction system which reacts quantitatively to the radiation. An anode of the group consisting of antimony and tungsten and a cathode of the group consisting of gold and platnium are inserted into the system. Means are provided to stir the system and a potential sensing device is connected across the anode and cathode to detect voltage changes. (AEC)

  19. Mapping methane sources and emissions over California from direct airborne flux and VOC source tracer measurements

    NASA Astrophysics Data System (ADS)

    Guha, A.; Misztal, P. K.; Peischl, J.; Karl, T.; Jonsson, H. H.; Woods, R. K.; Ryerson, T. B.; Goldstein, A. H.

    2013-12-01

    Quantifying the contributions of methane (CH4) emissions from anthropogenic sources in the Central Valley of California is important for validation of the statewide greenhouse gas (GHG) inventory and subsequent AB32 law implementation. The state GHG inventory is largely based on activity data and emission factor based estimates. The 'bottom-up' emission factors for CH4 have large uncertainties and there is a lack of adequate 'top-down' measurements to characterize emission rates. Emissions from non-CO2 GHG sources display spatial heterogeneity and temporal variability, and are thus, often, poorly characterized. The Central Valley of California is an agricultural and industry intensive region with large concentration of dairies and livestock operations, active oil and gas fields and refining operations, as well as rice cultivation all of which are known CH4 sources. In order to gain a better perspective of the spatial distribution of major CH4 sources in California, airborne measurements were conducted aboard a Twin Otter aircraft for the CABERNET (California Airborne BVOC Emissions Research in Natural Ecosystems Transects) campaign, where the driving research goal was to understand the spatial distribution of biogenic VOC emissions. The campaign took place in June 2011 and encompassed over forty hours of low-altitude and mixed layer airborne CH4 and CO2 measurements alongside coincident VOC measurements. Transects during eight unique flights covered much of the Central Valley and its eastern edge, the Sacramento-San Joaquin delta and the coastal range. We report direct quantification of CH4 fluxes using real-time airborne Eddy Covariance measurements. CH4 and CO2 were measured at 1-Hz data rate using an instrument based on Cavity Ring Down Spectroscopy (CRDS) along with specific VOCs (like isoprene, methanol, acetone etc.) measured at 10-Hz using Proton Transfer Reaction Mass Spectrometer - Eddy Covariance (PTRMS-EC) flux system. Spatially resolved eddy covariance

  20. Measurements of total reactive nitrogen during the Airborne Arctic Stratospheric Expedition

    NASA Technical Reports Server (NTRS)

    Kawa, S. R.; Fahey, D. W.; Anderson, L. C.; Loewenstein, M.; Chan, K. R.

    1990-01-01

    Composite distributions of measured total reactive nitrogen NO(y), from the NASA ER-2 during the Airborne Arctic Stratospheric Expedition are presented. The observed features of these distributions are discussed in terms of the controlling dynamical, chemical and microphysical processes. In the latitudinal profile from 58 deg N to within about 4 deg poleward of the polar vortex boundary, NO(y) conforms closely to predictions of NO(y) based on N2O measurements. Poleward of 5 deg of latitude within the boundary, the average NO(y) decreases sharply and is significantly lower than that predicted from N2O. This feature is consistent with loss of NO(y) through sedimentation of particles containing NO(y) in polar stratospheric clouds.

  1. Airborne Measurements of Formaldehyde Employing a Tunable Diode Laser Absorption Spectrometer During TRACE-P

    NASA Technical Reports Server (NTRS)

    Fried, Alan; Drummond, James

    2003-01-01

    This final report summarizes the progress achieved over the entire 3-year proposal period including two extensions spanning 1 year. These activities include: 1) Preparation for and participation in the NASA 2001 TRACE-P campaign using our airborne tunable diode laser system to acquire measurements of formaldehyde (CH2O); 2) Comprehensive data analysis and data submittal to the NASA archive; 3) Follow up data interpretation working with NASA modelers to place our ambient CH2O measurements into a broader photochemical context; 4) Publication of numerous JGR papers using this data; 5) Extensive follow up laboratory tests on the selectivity and efficiency of our CH20 scrubbing system; and 6) An extensive follow up effort to assess and study the mechanical stability of our entire optical system, particularly the multipass absorption cell, with aircraft changes in cabin pressure.

  2. A Micro Aerosol Sensor for the Measurement of Airborne Ultrafine Particles

    PubMed Central

    Zhang, Chao; Zhu, Rong; Yang, Wenming

    2016-01-01

    Particle number concentration and particle size are the two key parameters used to characterize exposure to airborne nanoparticles or ultrafine particles that have attracted the most attention. This paper proposes a simple micro aerosol sensor for detecting the number concentration and particle size of ultrafine particles with diameters from 50 to 253 nm based on electrical diffusion charging. The sensor is composed of a micro channel and a couple of planar electrodes printed on two circuit boards assembled in parallel, which thus integrate charging, precipitating and measurement elements into one chip, the overall size of which is 98 × 38 × 25 mm3. The experiment results demonstrate that the sensor is useful for measuring monodisperse aerosol particles with number concentrations from 300 to 2.5 × 104 /cm3 and particle sizes from 50 to 253 nm. The aerosol sensor has a simple structure and small size, which is favorable for use in handheld devices. PMID:26999156

  3. Airborne Carbon Dioxide Laser Absorption Spectrometer for IPDA Measurements of Tropospheric CO2: Recent Results

    NASA Technical Reports Server (NTRS)

    Spiers, Gary D.; Menzies, Robert T.

    2008-01-01

    The National Research Council's decadal survey on Earth Science and Applications from Space[1] recommended the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission for launch in 2013-2016 as a logical follow-on to the Orbiting Carbon Observatory (OCO) which is scheduled for launch in late 2008 [2]. The use of a laser absorption measurement technique provides the required ability to make day and night measurements of CO2 over all latitudes and seasons. As a demonstrator for an approach to meeting the instrument needs for the ASCENDS mission we have developed the airborne Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) which uses the Integrated Path Differential Absorption (IPDA) Spectrometer [3] technique operating in the 2 micron wavelength region.. During 2006 a short engineering checkout flight of the CO2LAS was conducted and the results presented previously [4]. Several short flight campaigns were conducted during 2007 and we report results from these campaigns.

  4. Oil film thickness measurement using airborne laser-induced water Raman backscatter

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1980-01-01

    The use of laser-induced water Raman backscatter for remote thin oil film detection and thickness measurement is reported here for the first time. A 337.1-nm nitrogen laser was used to excite the 3400-cm-1 OH stretch band of natural ocean water beneath the oil slick from an altitude of 150 m. The signal strength of the 381-nm water Raman backscatter was always observed to depress when the oil was encountered and then return to its original undepressed value after complete aircraft traversal of the floating slick. After removal of background and oil fluorescence contributions, the ratio of the depressed-to-undepressed airborne water Raman signal intensities, together with laboratory measured oil extinction coefficients, is used to calculate the oil film thickness.

  5. Measurements of Ultra-fine and Fine Aerosol Particles over Siberia: Large-scale Airborne Campaigns

    NASA Astrophysics Data System (ADS)

    Arshinov, Mikhail; Paris, Jean-Daniel; Stohl, Andreas; Belan, Boris; Ciais, Philippe; Nédélec, Philippe

    2010-05-01

    In this paper we discuss the results of in-situ measurements of ultra-fine and fine aerosol particles carried out in the troposphere from 500 to 7000 m in the framework of several International and Russian State Projects. Number concentrations of ultra-fine and fine aerosol particles measured during intensive airborne campaigns are presented. Measurements carried over a great part of Siberia were focused on particles with diameters from 3 to 21 nm to study new particle formation in the free/upper troposphere over middle and high latitudes of Asia, which is the most unexplored region of the Northern Hemisphere. Joint International airborne surveys were performed along the following routes: Novosibirsk-Salekhard-Khatanga-Chokurdakh-Pevek-Yakutsk-Mirny-Novosibirsk (YAK-AEROSIB/PLARCAT2008 Project) and Novosibirsk-Mirny-Yakutsk-Lensk-Bratsk-Novosibirsk (YAK-AEROSIB Project). The flights over Lake Baikal was conducted under Russian State contract. Concentrations of ultra-fine and fine particles were measured with automated diffusion battery (ADB, designed by ICKC SB RAS, Novosibirsk, Russia) modified for airborne applications. The airborne ADB coupled with CPC has an additional aspiration unit to compensate ambient pressure and changing flow rate. It enabled to classify nanoparticles in three size ranges: 3-6 nm, 6-21 nm, and 21-200 nm. To identify new particle formation events we used similar specific criteria as Young et al. (2007): (1) N3-6nm >10 cm-3, (2) R1=N3-6/N621 >1 and R2=N321/N21200 >0.5. So when one of the ratios R1 or R2 tends to decrease to the above limits the new particle formation is weakened. It is very important to notice that space scale where new particle formation was observed is rather large. All the events revealed in the FT occurred under clean air conditions (low CO mixing ratios). Measurements carried out in the atmospheric boundary layer over Baikal Lake did not reveal any event of new particle formation. Concentrations of ultra

  6. Airborne Flux Measurements of Volatile Organic Compounds and NOx over a European megacity

    NASA Astrophysics Data System (ADS)

    Shaw, Marvin; Lee, James; Davison, Brian; Misztal, Pawel; Karl, Thomas; Hewitt, Nick; Lewis, Alistair

    2014-05-01

    Ground level ozone (O3) and nitrogen dioxide (NO2) are priority pollutants whose concentrations are closely regulated by European Union Air Quality Directive 2008/50/EC. O3 is a secondary pollutant, produced from a complex chemical interplay between oxides of nitrogen (NOx = NO + NO2) and volatile organic compounds (VOCs). Whilst the basic atmospheric chemistry leading to O3 formation is generally well understood, there are substantial uncertainties associated with the magnitude of emissions of both VOCs and NOx. At present our knowledge of O3 precursor emissions in the UK is primarily derived from National Atmospheric Emission inventories (NAEI) that provide spatially disaggregated estimates at 1x1km resolution, and these are not routinely tested at city or regional scales. Uncertainties in emissions propagate through into uncertainties in predictions of air quality in the future, and hence the likely effectiveness of control policies on both background and peak O3 and NO2 concentrations in the UK. The Ozone Precursor Fluxes in the Urban Environment (OPFUE) project aims to quantify emission rates for NOx and selected VOCs in and around the megacity of London using airborne eddy covariance (AEC). The mathematical foundation for AEC has been extensively reviewed and AEC measurements of ozone, dimethyl sulphide, CO2 and VOCs have been previously reported. During the summer of 2013, approximately 30 hours of airborne flux measurements of toluene, benzene, NO and NO2 were obtained from the NERC Airborne Research and Survey Facility's (ARSF) Dornier-228 aircraft. Over SE England, flights involved repeated south west to north east transects of ~50 km each over Greater London and it's surrounding suburbs and rural areas, flying at the aircraft's minimum operating flight altitude and airspeed (~300m, 80m/s). Mixing ratios of benzene and toluene were acquired at 2Hz using a proton transfer reaction mass spectrometer (PTR-MS) and compared to twice hourly whole air canister

  7. Preliminary results of radiation measurements on EURECA

    SciTech Connect

    Benton, E.V.; Frank, A.L.

    1995-03-01

    The eleven-month duration of the EURECA mission allows long-term radiation effects to be studied similarly to those of the Long Duration Exposure Facility (LDEF). Basic data can be generated for projections to crew doses and electronic and computer reliability on spacecraft missions. A radiation experiment has been designed for EURECA which uses passive integrating detectors to measure average radiation levels. The components include a Trackoscope, which employs fourteen plastic nuclear track detector (PNTD) stacks to measure the angular dependence of high LET (greater than or equal to 6 keV/micro m) radiation. Also included are TLD`s for total absorbed doses, thermal/resonance neutron detectors (TRND`s) for low energy neutron fluences and a thick PNTD stack for depth dependence measurements. LET spectra are derived from the PNTD measurements. Preliminary TLD results from seven levels within the detector array show that integrated dose inside the flight canister varied from 18.8 +/- 0.6 cGy to 38.9 +/- 1.2 cGy. The TLD`s oriented toward the least shielded direction averaged 53% higher in dose than those oriented away from the least shielded direction (minimum shielding toward the least shielded direction varied from 1.13 to 7.9 g/cm(exp 2), Al equivalent). The maximum dose rate on EURECA (1.16 mGy/day) was 37% of the maximum measured on LDEF and dose rates at all depths were less than measured on LDEF. The shielding external to the flight canister covered a greater solid angle about the canister than the LDEF experiments.

  8. Sampling for Airborne Radioactivity

    DTIC Science & Technology

    2007-10-01

    compared to betas, gammas and neutrons. For an airborne radioactivity detection system, it is most important to be able to detect alpha particles and... Airborne radioactive particles may emit alpha, beta, gamma or neutron radiation, depending on which radioisotope is present. From a health perspective...

  9. Feasibility Study of an Airborne 1.6-μm Pulsed IPDA Lidar for Measuring Atmospheric Methane

    NASA Astrophysics Data System (ADS)

    Refaat, T. F.; Ismail, S.; Nehrir, A. R.; Hair, J. W.; Crawford, J. H.; Leifer, I.; Shuman, T.

    2013-12-01

    Atmospheric methane (CH4) has the second largest radiative forcing of the long-lived greenhouse gasses after carbon dioxide (CO2). However, methane's much shorter atmospheric lifetime and much stronger warming potential make its radiative forcing equivalent to that for CO2 over a 20-year time horizon as compared to the more commonly cited 100-year period. This makes CH4 a particularly attractive target for mitigation strategies. Development of CH4 active remote sensing capability employing the differential absorption lidar (DIAL) technique enables scientific assessments of both natural and anthropogenic sources and sinks of the gas and its impacts on the climate. A feasibility study of a pulsed DIAL system for monitoring atmospheric methane is presented. This system leverages a high power and high pulse repetition frequency injection-seeded Nd:YAG pumped Optical Parametric Oscillator laser operating in the 1.645 μm spectral band. The system also leverages an efficient low noise, commercially available, InGaAs avalanche photodiode. Lidar signals and error budget were analyzed for this system while operating on ground in the range-resolved DIAL mode and from airborne platforms in the integrated path DIAL (IPDA) mode over varying surface albedos. The analysis is based on optical depth calculations assuming US standard atmospheric model and molecular absorption line parameters from the HITRAN 2008 database. Error budget included systematic and random errors. Systematic errors comprise uncertainties in the knowledge of environmental and transmitter spectral properties. Environmental error sources included the uncertainty in the knowledge of molecular interference, temperature, pressure and relative humidity. Transmitter errors included the uncertainty in the laser line width and jitter for the on-line and off-line wavelengths. Random errors included all noise sources associated with the detection system electronics beside signals shot noises. Results from this study

  10. Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption in the ASCENDS 2011 Airborne Campaign

    NASA Technical Reports Server (NTRS)

    Abshire, James B.; Riris, Haris; Allan, Graham R.; Ramanathan, Anand; Hasselbrack, William E.; Mao, Jianping; Weaver, Clark; Browell, Edward V.

    2012-01-01

    We have previously demonstrated an efficient pulsed, wavelength-resolved IPDA lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission. Our team participated in the 2010 ASCENDS airborne campaigns we flew airborne version of the CO2 and O2 lidar on the NASA DC-8. The CO2 lidar measures the atmospheric backscatter profiles and shape of the 1572.33 nm absorption line using 250 mW average laser power, 30 wavelength samples per scan and 300 scans per second. Most flights had 5-6 altitude steps to greater than 12 km, and clear CO2 line shapes were observed at all altitudes. Our post-flight analysis estimated the Iidar range and pulse energies at each wavelength every second. We then solved for the best-fit CO2 absorption line shape, and calculated the Differential Optical Depth (DOD) at the line peak. We compared these to CO2 DODs calculated from spectroscopy based on HITRAN 2008 and the conditions from airborne in-situ readings. Analysis of the 2010 measurements over the Pacific Ocean and Lamont OK shows the expected -linear change of the peak DOD with altitude. For measurements at altitudes greater than 6 km the random errors were approximately 0.3 ppm for 80 sec averaging times. After the 2010 flights we improved the airborne lidar's scan uniformity, calibration and receiver sensitivity. Our team participated in the seven ASCENDS science flights during late July and August 2011. These flights were made over a wide variety of surface and cloud conditions near the US, including over the central valley of California, over several mountain ranges, over both broken and solid stratus cloud deck over the Pacific Ocean, snow patches on mountain tops, over thin and broken clouds above the US Southwest and Iowa, and over forests near the WLEF tower in Wisconsin. Analyses show the retrievals of lidar range and CO2 column absorption, as wen as estimates of CO2 mixing ratio worked well when measuring over topography with rapidly

  11. Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption in the ASCENDS 2011 Airborne Campaign

    NASA Astrophysics Data System (ADS)

    Abshire, J. B.; Riris, H.; Allan, G. R.; Ramanathan, A.; Hasselbrack, W.; Mao, J.; Weaver, C. J.; Browell, E. V.

    2012-12-01

    We have previously demonstrated an efficient pulsed, wavelength-resolved IPDA lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission. Our team participated in the 2010 ASCENDS airborne campaigns we flew airborne version of the CO2 and O2 lidar on the NASA DC-8. The CO2 lidar measures the atmospheric backscatter profiles and shape of the 1572.33 nm absorption line using 250 mW average laser power, 30 wavelength samples per scan and 300 scans per second. Most flights had 5-6 altitude steps to > 12 km, and clear CO2 line shapes were observed at all altitudes. Our post-flight analysis estimated the lidar range and pulse energies at each wavelength every second. We then solved for the best-fit CO2 absorption line shape, and calculated the Differential Optical Depth (DOD) at the line peak. We compared these to CO2 DODs calculated from spectroscopy based on HITRAN 2008 and the conditions from airborne in-situ readings. Analysis of the 2010 measurements over the Pacific Ocean and Lamont OK shows the expected ~linear change of the peak DOD with altitude. For measurements at altitudes > 6 km the random errors were ~ 0.3 ppm for 80 sec averaging times. After the 2010 flights we improved the airborne lidar's scan uniformity, calibration and receiver sensitivity. Our team participated in the seven ASCENDS science flights during late July and August 2011. These flights were made over a wide variety of surface and cloud conditions near the US, including over the central valley of California, over several mountain ranges, over both broken and solid stratus cloud deck over the Pacific Ocean, snow patches on mountain tops, over thin and broken clouds above the US Southwest and Iowa, and over forests near the WLEF tower in Wisconsin. Analyses show the retrievals of lidar range and CO2 column absorption, as well as estimates of CO2 mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity

  12. 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.

  13. Spectral optical layer properties of cirrus from collocated airborne measurements and simulations

    NASA Astrophysics Data System (ADS)

    Finger, Fanny; Werner, Frank; Klingebiel, Marcus; Ehrlich, André; Jäkel, Evelyn; Voigt, Matthias; Borrmann, Stephan; Spichtinger, Peter; Wendisch, Manfred

    2016-06-01

    Spectral upward and downward solar irradiances from vertically collocated measurements above and below a cirrus layer are used to derive cirrus optical layer properties such as spectral transmissivity, absorptivity, reflectivity, and cloud top albedo. The radiation measurements are complemented by in situ cirrus crystal size distribution measurements and radiative transfer simulations based on the microphysical data. The close collocation of the radiative and microphysical measurements, above, beneath, and inside the cirrus, is accomplished by using a research aircraft (Learjet 35A) in tandem with the towed sensor platform AIRTOSS (AIRcraft TOwed Sensor Shuttle). AIRTOSS can be released from and retracted back to the research aircraft by means of a cable up to a distance of 4 km. Data were collected from two field campaigns over the North Sea and the Baltic Sea in spring and late summer 2013. One measurement flight over the North Sea proved to be exemplary, and as such the results are used to illustrate the benefits of collocated sampling. The radiative transfer simulations were applied to quantify the impact of cloud particle properties such as crystal shape, effective radius reff, and optical thickness τ on cirrus spectral optical layer properties. Furthermore, the radiative effects of low-level, liquid water (warm) clouds as frequently observed beneath the cirrus are evaluated. They may cause changes in the radiative forcing of the cirrus by a factor of 2. When low-level clouds below the cirrus are not taken into account, the radiative cooling effect (caused by reflection of solar radiation) due to the cirrus in the solar (shortwave) spectral range is significantly overestimated.

  14. Mapping grassland leaf area index with airborne hyperspectral imagery: A comparison study of statistical approaches and inversion of radiative transfer models

    NASA Astrophysics Data System (ADS)

    Darvishzadeh, Roshanak; Atzberger, Clement; Skidmore, Andrew; Schlerf, Martin

    2011-11-01

    Statistical and physical models have seldom been compared in studying grasslands. In this paper, both modeling approaches are investigated for mapping leaf area index (LAI) in a Mediterranean grassland (Majella National Park, Italy) using HyMap airborne hyperspectral images. We compared inversion of the PROSAIL radiative transfer model with narrow band vegetation indices (NDVI-like and SAVI2-like) and partial least squares regression (PLS). To assess the performance of the investigated models, the normalized RMSE (nRMSE) and R2 between in situ measurements of leaf area index and estimated parameter values are reported. The results of the study demonstrate that LAI can be estimated through PROSAIL inversion with accuracies comparable to those of statistical approaches ( R2 = 0.89, nRMSE = 0.22). The accuracy of the radiative transfer model inversion was further increased by using only a spectral subset of the data ( R2 = 0.91, nRMSE = 0.18). For the feature selection wavebands not well simulated by PROSAIL were sequentially discarded until all bands fulfilled the imposed accuracy requirements.

  15. Hurricane Wind Field Measurements with Scanning Airborne Doppler Lidar During CAMEX-3

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; Cutten, D. R.; Howell, J. N.; Darby, L. S.; Hardesty, R. M.; Traff, D. M.; Menzies, R. T.

    2000-01-01

    During the 1998 Convection and Moisture Experiment (CAMEX-3), the first hurricane wind field measurements with Doppler lidar were achieved. Wind fields were mapped within the eye, along the eyewall, in the central dense overcast, and in the marine boundary layer encompassing the inflow region. Spatial coverage was determined primarily by cloud distribution and opacity. Within optically-thin cirrus slant range of 20- 25 km was achieved, whereas no propagation was obtained during penetration of dense cloud. Measurements were obtained with the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) on the NASA DC-8 research aircraft. MACAWS was developed and operated cooperatively by the atmospheric lidar remote sensing groups of NOAA Environmental Technology Laboratory, NASA Marshall Space Flight Center, and Jet Propulsion Laboratory. A pseudo-dual Doppler technique ("co-planar scanning") is used to map the horizontal component of the wind at several vertical levels. Pulses from the laser are directed out the left side of the aircraft in the desired directions using computer-controlled rotating prisms. Upon exiting the aircraft, the beam is completely eyesafe. Aircraft attitude and speed are taken into account during real-time signal processing, resulting in determination of the ground-relative wind to an accuracy of about 1 m/s magnitude and about 10 deg direction. Beam pointing angle errors are about 0.1 deg, equivalent to about 17 m at 10 km. Horizontal resolution is about 1 km (along-track) for typical signal processor and scanner settings; vertical resolution varies with range. Results from CAMEX-3 suggest that scanning Doppler wind lidar can complement airborne Doppler radar by providing wind field measurements in regions that are devoid of hydrometeors. At present MACAWS observations are being assimilated into experimental forecast models and satellite Doppler wind lidar simulations to evaluate the relative impact.

  16. Airborne IPDA Lidar Measurements of Atmospheric Methane in Support of MERLIN

    NASA Astrophysics Data System (ADS)

    Kiemle, C.; Amediek, A.; Wirth, M.; Ehret, G.

    2015-12-01

    Space-based lidar missions targeting greenhouse gases are expected to close observational gaps, e.g., over subarctic permafrost and tropical wetlands, where in-situ and passive remote sensing techniques have difficulties. Consequently, a "Methane Remote Lidar Mission" (MERLIN) was proposed by the German and French space agencies DLR and CNES. MERLIN is now in Phase B, in which all mission components are planned in detail; launch is foreseen in 2020. An integrated path differential absorption (IPDA) lidar will measure weighted columns of atmospheric methane (XCH4) along the satellite track. Primary objective is to provide accurate global observations of methane concentration gradients for inverse numerical models in order to better quantify regional fluxes. DLR has developed an airborne demonstrator, CHARM-F, for technology demonstration and validation purposes. First successful flights on-board the German HALO research aircraft have been performed in May 2015 over Central Europe. The measurements are expected to help solve general retrieval issues for future space-borne IPDA lidars. For example, the CHARM-F flights over ocean and lakes help assess the strength and variability of backscatter from water surfaces. The IPDA weighting function, or measurement sensitivity, is dependent on atmospheric pressure and temperature, in particular close to the surface. We use ECMWF analyses interpolated in space and time to the aircraft track that provide these auxiliary data at 14 km horizontal resolution. Due to the coarse representation of orography the model's pressure and temperature profiles have to be extrapolated down to the true lidar's scattering surface elevation, which generates uncertainties that we assess. We also assess biases by spectroscopic uncertainties in the methane absorption lines' parameters. Overall, the airborne results will support the development of advanced processing algorithms for future space lidar missions such as MERLIN.

  17. Radiation beam calorimetric power measurement system

    DOEpatents

    Baker, John; Collins, Leland F.; Kuklo, Thomas C.; Micali, James V.

    1992-01-01

    A radiation beam calorimetric power measurement system for measuring the average power of a beam such as a laser beam, including a calorimeter configured to operate over a wide range of coolant flow rates and being cooled by continuously flowing coolant for absorbing light from a laser beam to convert the laser beam energy into heat. The system further includes a flow meter for measuring the coolant flow in the calorimeter and a pair of thermistors for measuring the temperature difference between the coolant inputs and outputs to the calorimeter. The system also includes a microprocessor for processing the measured coolant flow rate and the measured temperature difference to determine the average power of the laser beam.

  18. Automatic actinometric system for diffuse radiation measurement

    NASA Astrophysics Data System (ADS)

    Litwiniuk, Agnieszka; Zajkowski, Maciej

    2015-09-01

    Actinometric station is using for measuring solar of radiation. The results are helpful in determining the optimal position of solar panels relative to the Sun, especially in today's world, when the energy coming from the Sun and other alternative sources of energy become more and more popular. Polish climate does not provide as much energy as in countries in southern Europe, but it is possible to increase the amount of energy produced by appropriate arrangement of photovoltaic panels. There is the possibility of forecasting the amount of produced energy, the cost-effectiveness and profitability of photovoltaic installations. This implies considerable development opportunities for domestic photovoltaic power plants. This article presents description of actinometric system for diffuse radiation measurement, which is equipped with pyranometer - thermopile temperature sensor, amplifier AD620, AD Converter ADS1110, microcontroller Atmega 16, SD card, GPS module and LCD screen.

  19. Airborne measurements of hygroscopicity and mixing state of aerosols in the planetary boundary layer during the PEGASOS campaigns

    NASA Astrophysics Data System (ADS)

    Rosati, Bernadette; Weingartner, Ernest; Gysel, Martin; Rubach, Florian; Mentel, Thomas; Baltensperger, Urs

    2014-05-01

    properties and mixing state. By combining these results with measurements from an aerosol mass spectrometer (AMS) and an aethalometer, insights can be gathered to explain their hygroscopicity. In this work we will present vertical profiles of the hygroscopic growth and mixing state of aerosol particles measured during Zeppelin flights of the PEGASOS campaigns in the Netherlands, Italy and Finland. Results from ground measurements will also be included to compare the aerosol directly at the surface with different heights. W.T. Morgan et al., Enhancement of the aerosol direct radiative effect by semi-volatile aerosol components: Airborne measurements in North-Western Europe, Atmospheric Chemistry and Physics 10(2010), pp. 8151-8171. P. Zieger et al., Comparison of ambient aerosol extinction coefficients obtained from in-situ, MAX-DOAS and LIDAR measurements at Cabauw, Atmospheric Chemistry and Physics 11(2011), pp. 2603-2624.

  20. Diode-pumped Nd:YAG lidar for airborne cloud measurements

    NASA Astrophysics Data System (ADS)

    Mehnert, A.; Halldorsson, Th.; Herrmann, H.; Haering, R.; Krichbaumer, W.; Streicher, J.; Werner, Ch.

    1992-07-01

    This work is concerned with the experimental method used to separate scattering and to use it for the determination of cloud microphysical parameters. It is also the first airborne test of a lidar version related to the ATLID Program - ESA's scheduled spaceborne lidar. The already tested DLR microlidar was modified with the new diode-pumped laser and a faster data recording system was added. The system was used during the CLEOPATRA campaign in the DLR research aircraft Falcon 20 to measure cloud parameters. The diode pumped Nd:YAG laser we developed for the microlidar is a modification of the laser we introduced at the Lidar Congress at 'Laser 1991' in Munich. Various aspects of this work are discussed.

  1. Airborne measurements of organic bromine compounds in the Pacific tropical tropopause layer

    PubMed Central

    Navarro, Maria A.; Atlas, Elliot L.; Saiz-Lopez, Alfonso; Rodriguez-Lloveras, Xavier; Kinnison, Douglas E.; Lamarque, Jean-Francois; Tilmes, Simone; Filus, Michal; Harris, Neil R. P.; Meneguz, Elena; Ashfold, Matthew J.; Manning, Alistair J.; Cuevas, Carlos A.; Schauffler, Sue M.; Donets, Valeria

    2015-01-01

    Very short-lived brominated substances (VSLBr) are an important source of stratospheric bromine, an effective ozone destruction catalyst. However, the accurate estimation of the organic and inorganic partitioning of bromine and the input to the stratosphere remains uncertain. Here, we report near-tropopause measurements of organic brominated substances found over the tropical Pacific during the NASA Airborne Tropical Tropopause Experiment campaigns. We combine aircraft observations and a chemistry−climate model to quantify the total bromine loading injected to the stratosphere. Surprisingly, despite differences in vertical transport between the Eastern and Western Pacific, VSLBr (organic + inorganic) contribute approximately similar amounts of bromine [∼6 (4−9) parts per thousand] to the stratospheric input at the tropical tropopause. These levels of bromine cause substantial ozone depletion in the lower stratosphere, and any increases in future abundances (e.g., as a result of aquaculture) will lead to larger depletions. PMID:26504212

  2. Precipitation susceptibility in marine stratocumulus and shallow cumulus from airborne measurements

    NASA Astrophysics Data System (ADS)

    Jung, Eunsil; Albrecht, Bruce A.; Sorooshian, Armin; Zuidema, Paquita; Jonsson, Haflidi H.

    2016-09-01

    Precipitation tends to decrease as aerosol concentration increases in warm marine boundary layer clouds at fixed liquid water path (LWP). The quantitative nature of this relationship is captured using the precipitation susceptibility (So) metric. Previously published works disagree on the qualitative behavior of So in marine low clouds: So decreases monotonically with increasing LWP or cloud depth (H) in stratocumulus clouds (Sc), while it increases and then decreases in shallow cumulus clouds (Cu). This study uses airborne measurements from four field campaigns on Cu and Sc with similar instrument packages and flight maneuvers to examine if and why So behavior varies as a function of cloud type. The findings show that So increases with H and then decreases in both Sc and Cu. Possible reasons for why these results differ from those in previous studies of Sc are discussed.

  3. GEANT4 calibration of gamma spectrometry efficiency for measurements of airborne radioactivity on filter paper.

    PubMed

    Alrefae, Tareq

    2014-11-01

    A simple method of efficiency calibration for gamma spectrometry was performed. This method, which focused on measuring airborne radioactivity collected on filter paper, was based on Monte Carlo simulations using the toolkit GEANT4. Experimentally, the efficiency values of an HPGe detector were calculated for a multi-gamma disk source. These efficiency values were compared to their counterparts produced by a computer code that simulated experimental conditions. Such comparison revealed biases of 24, 10, 1, 3, 7, and 3% for the radionuclides (photon energies in keV) of Ce (166), Sn (392), Cs (662), Co (1,173), Co (1,333), and Y (1,836), respectively. The output of the simulation code was in acceptable agreement with the experimental findings, thus validating the proposed method.

  4. Airborne measurements of organic bromine compounds in the Pacific tropical tropopause layer.

    PubMed

    Navarro, Maria A; Atlas, Elliot L; Saiz-Lopez, Alfonso; Rodriguez-Lloveras, Xavier; Kinnison, Douglas E; Lamarque, Jean-Francois; Tilmes, Simone; Filus, Michal; Harris, Neil R P; Meneguz, Elena; Ashfold, Matthew J; Manning, Alistair J; Cuevas, Carlos A; Schauffler, Sue M; Donets, Valeria

    2015-11-10

    Very short-lived brominated substances (VSLBr) are an important source of stratospheric bromine, an effective ozone destruction catalyst. However, the accurate estimation of the organic and inorganic partitioning of bromine and the input to the stratosphere remains uncertain. Here, we report near-tropopause measurements of organic brominated substances found over the tropical Pacific during the NASA Airborne Tropical Tropopause Experiment campaigns. We combine aircraft observations and a chemistry-climate model to quantify the total bromine loading injected to the stratosphere. Surprisingly, despite differences in vertical transport between the Eastern and Western Pacific, VSLBr (organic + inorganic) contribute approximately similar amounts of bromine [∼6 (4-9) parts per trillion] [corrected] to the stratospheric input at the tropical tropopause. These levels of bromine cause substantial ozone depletion in the lower stratosphere, and any increases in future abundances (e.g., as a result of aquaculture) will lead to larger depletions.

  5. Validating reconstruction of snow water equivalent in California's Sierra Nevada using measurements from the NASA Airborne Snow Observatory

    NASA Astrophysics Data System (ADS)

    Bair, Edward H.; Rittger, Karl; Davis, Robert E.; Painter, Thomas H.; Dozier, Jeff

    2016-11-01

    Accurately estimating basin-wide snow water equivalent (SWE) is the most important unsolved problem in mountain hydrology. Models that rely on remotely sensed inputs are especially needed in ranges with few surface measurements. The NASA Airborne Snow Observatory (ASO) provides estimates of SWE at 50 m spatial resolution in several basins across the Western U.S. during the melt season. Primarily, water managers use this information to forecast snowmelt runoff into reservoirs; another impactful use of ASO measurements lies in validating and improving satellite-based snow estimates or models that can scale to whole mountain ranges, even those without ground-based measurements. We compare ASO measurements from 2013 to 2015 to four methods that estimate spatially distributed SWE: two versions of a SWE reconstruction method, spatial interpolation from snow pillows and courses, and NOAA's Snow Data Assimilation System (SNODAS). SWE reconstruction downscales energy forcings to compute potential melt, then multiplies those values by satellite-derived estimates of fractional snow-covered area to calculate snowmelt. The snowpack is then built in reverse from the date the snow is observed to disappear. The two SWE reconstruction models tested include one that employs an energy balance calculation of snowmelt, and one that combines net radiation and degree-day approaches to estimate melt. Our full energy balance model, without ground observations, performed slightly better than spatial interpolation from snow pillows, having no systematic bias and 26% mean absolute error when compared to SWE from ASO. Both reconstruction models and interpolation were more accurate than SNODAS.

  6. Retrieval of Snow and Rain From Combined X- and W-B and Airborne Radar Measurements

    NASA Technical Reports Server (NTRS)

    Liao, Liang; Meneghini, Robert; Tian, Lin; Heymsfield, Gerald M.

    2008-01-01

    Two independent airborne dual-wavelength techniques, based on nadir measurements of radar reflectivity factors and Doppler velocities, respectively, are investigated with respect to their capability of estimating microphysical properties of hydrometeors. The data used to investigate the methods are taken from the ER-2 Doppler radar (X-band) and Cloud Radar System (W-band) airborne Doppler radars during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment campaign in 2002. Validity is assessed by the degree to which the methods produce consistent retrievals of the microphysics. For deriving snow parameters, the reflectivity-based technique has a clear advantage over the Doppler-velocity-based approach because of the large dynamic range in the dual-frequency ratio (DFR) with respect to the median diameter Do and the fact that the difference in mean Doppler velocity at the two frequencies, i.e., the differential Doppler velocity (DDV), in snow is small relative to the measurement errors and is often not uniquely related to Do. The DFR and DDV can also be used to independently derive Do in rain. At W-band, the DFR-based algorithms are highly sensitive to attenuation from rain, cloud water, and water vapor. Thus, the retrieval algorithms depend on various assumptions regarding these components, whereas the DDV-based approach is unaffected by attenuation. In view of the difficulties and ambiguities associated with the attenuation correction at W-band, the DDV approach in rain is more straightforward and potentially more accurate than the DFR method.

  7. Measurements of neutron radiation in aircraft.

    PubMed

    Vuković, B; Poje, M; Varga, M; Radolić, V; Miklavcić, I; Faj, D; Stanić, D; Planinić, J

    2010-12-01

    Radiation environment is a complex mixture of charged particles of the solar and galactic origin, as well as of secondary particles created in an interaction of galactic cosmic particles with the nuclei of the Earth's atmosphere. A radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. In order to measure a neutron component of the cosmic radiation, we investigated a few combinations of a track etch detector (CR-39, LR-115) with a plastic converter or boron foil. Detector calibration was performed on neutrons coming from the nuclear reactor, as well as in the CERN-EU high-energy Reference Field (CERF) facility. From November 2007 to September 2008, the neutron dose equivalent was measured by the track detectors during five aircraft flights, in the north geographical latitude from 21° to 58°; the respective average dose rate, determined by using the D-4 detector (CR-39/B), was Ḣ(n)=5.9 μSv/h. The photon dose rate, measured by the electronic dosimeter RAD-60 SE, had the average value of Ḣ(f)=1.4 μSv/h.

  8. Measurement and modelling of spectral solar radiation.

    NASA Astrophysics Data System (ADS)

    Dehne, K.; Czeplak, G.

    1996-03-01

    Small band measurements of spectral solar radiation by means of commercially available spectral radiometers, which are generally designed for laboratory work, require thorough aptitude tests and mostly special fitting measures. For the already available DM 150, first of all an entrance optics to correct cosine errors, a thermostatted weathercasing, as well as a special control lamp device for field use were developped. An international IEA-field intercomparison of 12 spectral radiometers in the Oberpfaffenhofen area of DLR showed deviations between the global radiation spectra of (+/-)15% and (+/-)40% for the best and the worst case, resp. The latter was caused by the operational requirements in the field and the mechanical instabilities of some radiometers (including the DM 150). Generally a remarkable portion of the deviations belongs to calibration uncertainties and imperfect cosine corrections. With regard to the summarized experience only principal recommendations on the use of spectral radiometers are given. Measured data of atmospheric heat radiation A and other meteorological data of 16 IEA stations were compiled in a data base at MOH to facilitate the fast uniform validation of 30 formulae for parametrization of A. For the case of sky clouded in 3 layers a parametrization formula was improved and successfully validated. A special reliable A-formula could be developped from the sufficiently high number of data of station Schleswig for the case of low cloudiness only.

  9. Radiation measurements on the Mir Orbital Station

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Atwell, W.; Reitz, G.; Beaujean, R.; Heinrich, W.

    2002-01-01

    Radiation measurements made onboard the MIR Orbital Station have spanned nearly a decade and covered two solar cycles, including one of the largest solar particle events, one of the largest magnetic storms, and a mean solar radio flux level reaching 250 x 10(4) Jansky that has been observed in the last 40 years. The cosmonaut absorbed dose rates varied from about 450 microGy day-1 during solar minimum to approximately half this value during the last solar maximum. There is a factor of about two in dose rate within a given module, and a similar variation from module to module. The average radiation quality factor during solar minimum, using the ICRP-26 definition, was about 2.4. The drift of the South Atlantic Anomaly was measured to be 6.0 +/- 0.5 degrees W, and 1.6 +/- 0.5 degrees N. These measurements are of direct applicability to the International Space Station. This paper represents a comprehensive review of Mir Space Station radiation data available from a variety of sources. c2002 Elsevier Science Ltd. All rights reserved.

  10. Airborne differential absorption lidar system for measurements of atmospheric water vapor and aerosols.

    PubMed

    Higdon, N S; Browell, E V; Ponsardin, P; Grossmann, B E; Butler, C F; Chyba, T H; Mayo, M N; Allen, R J; Heuser, A W; Grant, W B; Ismail, S; Mayor, S D; Carter, A F

    1994-09-20

    An airborne differential absorption lidar (DIAL) system has been developed at the NASA Langley Research Center for remote measurements of atmospheric water vapor (H(2)O) and aerosols. A solid-state alexandrite laser with a 1-pm linewidth and > 99.85% spectral purity was used as the on-line transmitter. Solid-state avalanche photodiode detector technology has replaced photomultiplier tubes in the receiver system, providing an average increase by a factor of 1.5-2.5 in the signal-to-noise ratio of the H(2)O measurement. By incorporating advanced diagnostic and data-acquisition instrumentation into other subsystems, we achieved additional improvements in system operational reliability and measurement accuracy. Laboratory spectroscopic measurements of H(2)O absorption-line parameters were perfo med to reduce the uncertainties in our knowledge of the absorption cross sections. Line-center H(2)O absorption cross sections were determined, with errors of 3-6%, for more than 120 lines in the 720-nm region. Flight tests of the system were conducted during 1989-1991 on the NASA Wallops Flight Facility Electra aircraft, and extensive intercomparison measurements were performed with dew-point hygrometers and H(2)O radiosondes. The H(2)O distributions measured with the DIAL system differed by ≤ 10% from the profiles determined with the in situ probes in a variety of atmospheric conditions.

  11. Airborne differential absorption lidar system for measurements of atmospheric water vapor and aerosols

    NASA Technical Reports Server (NTRS)

    Carter, Arlen F.; Allen, Robert J.; Mayo, M. Neale; Butler, Carolyn F.; Grossman, Benoist E.; Ismail, Syed; Grant, William B.; Browell, Edward V.; Higdon, Noah S.; Mayor, Shane D.; Ponsardin, Patrick; Hueser, Alene W.

    1994-01-01

    An airborne differential absorption lidar (DIAL) system has been developed at the NASA Langley Research Center for remote measurements of atmospheric water vapor (H2O) and aerosols. A solid-state alexandrite laser with a 1-pm linewidth and greater than 99.85% spectral purity was used as the on-line transmitter. Solid-state avalanche photodiode detector technology has replaced photomultiplier tubes in the receiver system, providing an average increase by a factor of 1.5-2.5 in the signal-to-noise ratio of the H2O measurement. By incorporating advanced diagnostic and data-acquisition instrumentation into other subsystems, we achieved additional improvements in system operational reliability and measurement accuracy. Laboratory spectroscopic measurements of H2O absorption-line parameters were performed to reduce the uncertainties in our knowledge of the absorption cross sections. Line-center H2O absorption cross sections were determined, with errors of 3-6%, for more than 120 lines in the 720-nm region. Flight tests of the system were conducted during 1989-1991 on the NASA Wallops Flight Facility Electra aircraft, and extensive intercomparison measurements were performed with dew-point hygrometers and H2O radiosondes. The H2O distributions measured with the DIAL system differed by less than 10% from the profiles determined with the in situ probes in a variety of atmospheric conditions.

  12. Radiation-dose estimates and hazard evaluations for inhaled airborne radionuclides. Annual progress report, July 1981-June 1982

    SciTech Connect

    Mewhinney, J.A.

    1983-06-01

    The objective was to conduct confirmatory research on aerosol characteristics and the resulting radiation dose distribution in animals following inhalation and to provide prediction of health consequences in humans due to airborne radioactivity which might be released in normal operations or under accident conditions during production of nuclear fuel composed of mixed oxides of U and Pu. Four research reports summarize the results of specific areas of research. The first paper details development of a method for determination of specific surface area of small samples of mixed oxide or pure PuO/sub 2/ particles. The second paper details the extension of the biomathematical model previously used to describe retention, distribution and excretion of Pu from these mixed oxide aerosols to include a description of Am and U components of these aerosols. The third paper summarizes the biological responses observed in radiation dose pattern studies in which dogs, monkeys and rate received inhalation exposures to either 750/sup 0/C heat treated UO/sub 2/ + PuO/sub 2/, 1750/sup 0/C heat-treated (U,Pu)O/sub 2/ or 850/sup 0/C heat-treated pure PuO/sub 2/. The fourth paper described dose-response studies in which rats were exposed to (U,Pu)O/sub 2/ or pure PuO/sub 2/. This paper updates earlier reports and summarizes the status of animals through approximately 650 days after inhalation.

  13. A new method for GPS-based wind speed determinations during airborne volcanic plume measurements

    USGS Publications Warehouse

    Doukas, Michael P.

    2002-01-01

    Begun nearly thirty years ago, the measurement of gases in volcanic plumes is today an accepted technique in volcano research. Volcanic plume measurements, whether baseline gas emissions from quiescent volcanoes or more substantial emissions from volcanoes undergoing unrest, provide important information on the amount of gaseous output of a volcano to the atmosphere. Measuring changes in gas emission rates also allows insight into eruptive behavior. Some of the earliest volcanic plume measurements of sulfur dioxide were made using a correlation spectrometer (COSPEC). The COSPEC, developed originally for industrial pollution studies, is an upward-looking optical spectrometer tuned to the ultraviolet absorption wavelength of sulfur dioxide (Millán and Hoff, 1978). In airborne mode, the COSPEC is mounted in a fixed-wing aircraft and flown back and forth just underneath a volcanic plume, perpendicular to the direction of plume travel (Casadevall and others, 1981; Stoiber and others, 1983). Similarly, for plumes close to the ground, the COSPEC can be mounted in an automobile and driven underneath a plume if a suitable road system is available (Elias and others, 1998). The COSPEC can also be mounted on a tripod and used to scan a volcanic plume from a fixed location on the ground, although the effectiveness of this configuration declines with distance from the plume (Kyle and others, 1990). In the 1990’s, newer airborne techniques involving direct sampling of volcanic plumes with infrared spectrometers and electrochemical sensors were developed in order to measure additional gases such as CO2 and H2S (Gerlach and others, 1997; Gerlach and others, 1999; McGee and others, 2001). These methods involve constructing a plume cross-section from several measurement traverses through the plume in a vertical plane. Newer instruments such as open-path Fourier transform infrared (FTIR) spectrometers are now being used to measure the gases in volcanic plumes mostly from fixed

  14. Disinfection of Airborne Organisms by Ultraviolet-C Radiation and Sunlight

    DTIC Science & Technology

    2012-07-01

    ranges. The emission of UV radiation from a mercury gas-filled light is illustrated in Figure 1. In this system, two high-voltage electrodes are placed...in a mercury -filled chamber. The arc between the electrodes provides the energy for the electrons of the mercury atoms to enter a higher energy...as having wavelengths between 280 and 315 nm. The availability of low- and medium-pressure mercury lamps makes UV radiation relatively easy and

  15. Advances in airborne remote sensing of ecosystem processes and properties: toward high-quality measurement on a global scale

    NASA Astrophysics Data System (ADS)

    Kampe, Thomas U.; Asner, Gregory P.; Green, Robert O.; Eastwood, Michael; Johnson, Brian R.; Kuester, Michele

    2010-08-01

    Airborne remote sensing provides the opportunity to quantitatively measure biochemical and biophysical properties of vegetation at regional scales, therefore complementing surface and satellite measurements. Next-generation programs are poised to advance ecological research and monitoring in the United States, the tropical regions of the globe, and to support future satellite missions. The Carnegie Institution will integrate a next generation imaging spectrometer with a waveform LiDAR into the Airborne Taxonomic Mapping System (AToMS) to identify the chemical, structural and taxonomic makeup of tropical forests at an unprecedented scale and detail. The NEON Airborne Observation Platform (AOP) is under development with similar technologies with a goal to provide long-term measurements of ecosystems across North America. The NASA Next Generation Airborne Visible/Infrared Imaging Spectrometer (AVIRISng) is also under development to address the science measurement requirements for both the NASA Earth Science Research and Analysis Program and the spaceborne NASA HyspIRI Mission. Carnegie AToMS, NEON AOP, and AVIRISng are being built by the Jet Propulsion Laboratory as a suite of instruments. We discuss the synergy between these programs and anticipated benefits to ecologists and decision-makers.

  16. *Evaluating the toxicity of airborne particulate matter and nanoparticles by measuring oxidative strett potential - A workshop report and consensus statement

    EPA Science Inventory

    BACKGROUND: There is a strong need for laboratory in vitro test systems for the toxicity of airborne particulate matter and nanoparticles. The measurement of oxidative stress potential offers a promising way forward. OBJECTIVES: A workshop was convened involving leading workers f...

  17. Airborne measurements of Black Carbon using miniature high-performance Aethalometers during global circumnavigation campaign GLWF 2012

    NASA Astrophysics Data System (ADS)

    Močnik, Griša; Drinovec, Luka; Vidmar, Primož; Lenarčič, Matevž

    2013-04-01

    While ground-level measurements of atmospheric aerosols are routinely performed around the world, there exists very little data on their vertical and geographical distribution in the global atmosphere. This data is a crucial requirement for our understanding of the dispersion of pollutant species of anthropogenic origin, and their possible effects on radiative forcing, cloud condensation, and other phenomena which can contribute to adverse outcomes. Black Carbon (BC) is a unique tracer for combustion emissions, and can be detected rapidly and with great sensitivity by filter-based optical methods. It has no non-combustion sources and is not transformed by atmospheric processes. Its presence at altitude is unequivocal. Recent technical advances have led to the development of miniaturized instruments which can be operated on ultra-light aircraft, balloons or UAV's. From January to April 2012, a 'Pipistrel Virus' single-seat ultra-light aircraft flew around the world on a photographic and environmental-awareness mission. The flight track covered all seven continents; crossed all major oceans; and operated at altitudes around 3000 m ASL and up to 8900 m ASL. The aircraft carried a specially-developed high-sensitivity miniaturized dual-wavelength Aethalometer, which recorded BC concentrations with very high temporal resolution and sensitivity (see Reference below). We present examples of data from flight tracks over remote oceans, uninhabited land masses, and densely populated areas. Back-trajectories are used to show transport of polluted air masses. Measuring the dependence of the aerosol absorption on the wavelength, we show that aerosols produced during biomass combustion can be transported to high altitude in high concentrations. 1. __, Carbon Sampling Takes Flight, Science 2012, 335, 1286. 2. G. Močnik, L. Drinovec, M. Lenarčič, Airborne measurements of Black Carbon during the GLW Flight using miniature high-performance Aethalometers, accessed 8 January 2013

  18. Airborne Lidar Measurements of Atmospheric Column CO2 Concentration to Cloud Tops

    NASA Astrophysics Data System (ADS)

    Mao, J.; Ramanathan, A. K.; Abshire, J. B.; Kawa, S. R.; Riris, H.; Allan, G. R.; Hasselbrack, W. E.

    2015-12-01

    Globally distributed atmospheric CO2 measurements with high precision, low bias and full seasonal sampling are crucial to advance carbon cycle sciences. However, two thirds of the Earth's surface is typically covered by clouds, and passive remote sensing approaches from space, e.g., OCO-2 and GOSAT, are limited to cloud-free scenes. They are unable to provide useful retrievals in cloudy areas where the photon path-length can't be well characterized. Thus, passive approaches have limited global coverage and poor sampling in cloudy regions, even though some cloudy regions have active carbon surface fluxes. NASA Goddard is developing a pulsed integrated-path, differential absorption (IPDA) lidar approach to measure atmospheric column CO2 concentrations from space as a candidate for NASA's ASCENDS mission. Measurements of time-resolved laser backscatter profiles from the atmosphere also allow this technique to estimate column CO2 and range to cloud tops in addition to those to the ground with precise knowledge of the photon path-length. This allows retrievals of column CO2 concentrations to cloud tops, providing much higher spatial coverage and some information about vertical structure of CO2. This is expected to benefit atmospheric transport process studies, carbon data assimilation in models, and global and regional carbon flux estimation. We show some preliminary results of the all-sky retrieval capability using airborne lidar measurements from the 2011, 2013 and 2014 ASCENDS airborne campaigns on the NASA DC-8. These show retrievals of atmospheric CO2 over low-level marine stratus clouds, cumulus clouds at the top of planetary boundary layer, some mid-level clouds and visually thin high-level cirrus clouds. The CO2 retrievals from the lidar are validated against in-situ measurements and compared to Goddard PCTM model simulations. Lidar cloud slicing to derive CO2 abundance in the planetary boundary layer and free troposphere also has been demonstrated. The

  19. Bunch Length Measurements using Coherent Radiation

    SciTech Connect

    Ischebeck, Rasmus; Barnes, Christopher; Blumenfeld, Ian; Decker, Franz-Josef; Hogan, Mark; Iverson, Richard H.; Krejcik, Patrick; Siemann, Robert H.; Walz, Dieter; Kirby, Neil; Clayton, Chris; Huang, Chengkun; Johnson, Devon K.; Lu, Wei; Marsh, Ken; Deng, Suzhi; Oz, Erdem; /Southern California U.

    2005-06-24

    The accelerating field that can be obtained in a beam-driven plasma wakefield accelerator depends on the current of the electron beam that excites the wake. In the E-167 experiment, a peak current above 10 kA will be delivered at a particle energy of 28 GeV. The bunch has a length of a few ten micrometers and several methods are used to measure its longitudinal profile. Among these, autocorrelation of coherent transition radiation (CTR) is employed. The beam passes a thin metallic foil, where it emits transition radiation. For wavelengths greater than the bunch length, this transition radiation is emitted coherently. This amplifies the long-wavelength part of the spectrum. A scanning Michelson interferometer is used to autocorrelate the CTR. However, this method requires the contribution of many bunches to build an autocorrelation trace. The measurement is influenced by the transmission characteristics of the vacuum window and beam splitter. We present here an analysis of materials, as well as possible layouts for a single shot CTR autocorrelator.

  20. Measuring ionizing radiation with a mobile device

    NASA Astrophysics Data System (ADS)

    Michelsburg, Matthias; Fehrenbach, Thomas; Puente León, Fernando

    2012-02-01

    In cases of nuclear disasters it is desirable to know one's personal exposure to radioactivity and the related health risk. Usually, Geiger-Mueller tubes are used to assess the situation. Equipping everyone with such a device in a short period of time is very expensive. We propose a method to detect ionizing radiation using the integrated camera of a mobile consumer device, e.g., a cell phone. In emergency cases, millions of existing mobile devices could then be used to monitor the exposure of its owners. In combination with internet access and GPS, measured data can be collected by a central server to get an overview of the situation. During a measurement, the CMOS sensor of a mobile device is shielded from surrounding light by an attachment in front of the lens or an internal shutter. The high-energy radiation produces free electrons on the sensor chip resulting in an image signal. By image analysis by means of the mobile device, signal components due to incident ionizing radiation are separated from the sensor noise. With radioactive sources present significant increases in detected pixels can be seen. Furthermore, the cell phone application can make a preliminary estimate on the collected dose of an individual and the associated health risks.

  1. Remote estimation of canopy nitrogen content in winter wheat using airborne hyperspectral reflectance measurements

    NASA Astrophysics Data System (ADS)

    Zhou, Xianfeng; Huang, Wenjiang; Kong, Weiping; Ye, Huichun; Luo, Juhua; Chen, Pengfei

    2016-11-01

    Timely and accurate assessment of canopy nitrogen content (CNC) provides valuable insight into rapid and real-time nitrogen status monitoring in crops. A semi-empirical approach based on spectral index was extensively used for nitrogen content estimation. However, in many cases, due to specific vegetation types or local conditions, the applicability and robustness of established spectral indices for nitrogen retrieval were limited. The objective of this study was to investigate the optimal spectral index for winter wheat (Triticum aestivum L.) CNC estimation using Pushbroom Hyperspectral Imager (PHI) airborne hyperspectral data. Data collected from two different field experiments that were conducted during the major growth stages of winter wheat in 2002 and 2003 were used. Our results showed that a significant linear relationship existed between nitrogen and chlorophyll content at the canopy level, and it was not affected by cultivars, growing conditions and nutritional status of winter wheat. Nevertheless, it varied with growth stages. Periods around heading stage mainly worsened the relationship and CNC estimation, and CNC assessment for growth stages before and after heading could improve CNC retrieval accuracy to some extent. CNC assessment with PHI airborne hyperspectra suggested that spectral indices based on red-edge band including narrowband and broadband CIred-edge, NDVI-like and ND705 showed convincing results in CNC retrieval. NDVI-like and ND705 were sensitive to detect CNC changes less than 5 g/m2, narrowband and broadband CIred-edge were sensitive to a wide range of CNC variations. Further evaluation of CNC retrieval using field measured hyperspectra indicated that NDVI-like was robust and exhibited the highest accuracy in CNC assessment, and spectral indices (CIred-edge and CIgreen) that established on narrow or broad bands showed no obvious difference in CNC assessment. Overall, our study suggested that NDVI-like was the optimal indicator for winter

  2. Atmospheric dispersion of airborne pollen evidenced by near-surface and columnar measurements in Barcelona, Spain

    NASA Astrophysics Data System (ADS)

    Sicard, Michaël.; Izquierdo, Rebeca; Jorba, Oriol; Alarcón, Marta; Belmonte, Jordina; Comerón, Adolfo; De Linares, Concepción; Baldasano, José Maria

    2016-10-01

    Hourly measurements of pollen near-surface concentration and lidar-derived profiles of volume and particle depolarization ratios during a 5-day pollination event observed in Barcelona, Spain, between 27 - 31 March, 2015, are presented. Maximum hourly pollen concentrations of 4700 and 1200 m-3 h-1 were found for Platanus and Pinus, respectively, which represented together more than 80 % of the total pollen. . The pollen concentration was found positively correlated with temperature (correlation coefficient, r, of 0.95) and wind speed (r = 0.82) and negatively correlated with relative humidity (r = -0.18). The ground concentration shows a clear diurnal cycle although pollen activity is also detected during nighttime in three occasions and is clearly associated with periods of strong wind speeds. Everyday a clear diurnal cycle caused by the vertical transport of the airborne pollen was visible on the lidar-derived profiles of the volume depolarization ratio with maxima usually reached between 12 and 15 UT. On average the volume depolarization ratios in the pollen plume ranged between 0.08 and 0.22. Except in the cases of nocturnal pollen activity, the correlation coefficients between volume depolarization ratio and near-surface concentration are high (>0.68). The dispersion of the Platanus and Pinus in the atmosphere was simulated with the Nonhydrostatic Multiscale Meteorological Model on the B grid at the Barcelona Supercomputing Center with a newly developed Chemical Transport Model (NMMB/BSC-CTM). Model near-surface daily pollen concentrations were compared to our observations at two sites: in Barcelona and Bellaterra (12 km NE of Barcelona). Model hourly pollen concentrations were compared to our observations in Barcelona. Better results are obtained for Pinus than for Platanus. Guidelines are proposed to improve the dispersion of airborne pollen by atmospheric models.

  3. Integrating nephelometer measurements for the airborne fine particulate matter (PM 2.5) mass concentrations

    NASA Astrophysics Data System (ADS)

    Shendrikar, Arun D.; Steinmetz, William K.

    This work describes the application of integrating nephelometer measurements for the determination of airborne fine particulate matter (PM 2.5) mass concentrations. In response to over 150 complaints (spanning a period of 20 years) from local citizens of irritant fogs and pungent odors, the North Carolina Division of Air Quality conducted a monitoring program, in collaboration with the Washington Regional Air Quality Office and PCS Phosphate, Inc., to characterize air quality in the Pamlico River airshed of eastern North Carolina. The continuous monitoring from 1 May through 31 October 2000 at four sites, involved collection of air samples and subsequent quantification for reactive acidic and basic gases, aerosols and fine particulate matter (PM 2.5) using a 7-day Annular Denuder System (ADS). Additionally, the airborne concentration of the fine particulate matter (PM 2.5) was concurrently (to the ADS) monitored using a tapered element oscillating micro-balance (TEOM). Relevant meteorological data were obtained from conventional sensors installed at each sampling site. An integrating nephelometer was used for the regional visibility measurements. An integrating nephelometer was used to measure light scattering (a surrogate for visibility) continuously for 24-h per day over a 6-month period at the four sites. A linear relationship has been found for the nephelometer (Beta scat) measurements and mass data (PM 2.5) obtained both from the TEOM and ADS. The calculated correlation coefficient results between nephelometer and ADS and nephelometer and TEOM are satisfactory and close to one. This indicates that in this region, the nephelometer measurements have the potential to be a surrogate for the determination of regional airborne fine particle (PM 2.5) mass concentrations. The ratios for each of the four sampling sites using 24-h averages of nephelometer data and PM 2.5 concentrations from the ADS units and the TEOM gave an average ratio of 0.32±0.02. This value

  4. A Radiometer for Precision Coherent Radiation Measurements

    PubMed Central

    Thomas, Douglas B.; Zalewski, Edward F.

    1992-01-01

    A radiometer has been designed for precision colierent radiation measurements and tested for long-term repeatability at wavelengths of 488 and 633 nm. The radiometer consists of a pn silicon photodiode maintained in a nitrogen atmosphere with a quartz window designed to eliminate interference problems. Ratio measurements between the radiometer and an absolute type detector were made over a period of 215 d. At 0.5 mW, the standard deviations were 0.008% and 0.009% at 488 and 633 nm, respectively. The maximum deviations from the mean were 0.016% and 0.015% at the respective wavelengths. Measurements were also made on the radiometer with respect to angular and spatial uniformity and linearity. The high precision, simplicity, and portability of the radiometer suggest it for use as a transfer standard for radiometric measurements. PMID:28053435

  5. An Assessment of the Surface Longwave Direct Radiative Effect of Airborne Saharan Dust During the NAMMA Field Campaign

    NASA Technical Reports Server (NTRS)

    Hansell, R. A.; Tsay, S. C.; Ji, Q.; Hsu, N. C.; Jeong, M. J.; Wang, S. H.; Reid, J. S.; Liou, K. N.; Ou, S. C.

    2010-01-01

    In September 2006, NASA Goddard s mobile ground-based laboratories were deployed to Sal Island in Cape Verde (16.73degN, 22.93degW) to support the NASA African Monsoon Multidisciplinary Analysis (NAMMA) field study. The Atmospheric Emitted Radiance Interferometer (AERI), a key instrument for spectrally characterizing the thermal IR, was used to retrieve the dust IR aerosol optical depths (AOTs) in order to examine the diurnal variability of airborne dust with emphasis on three separate dust events. AERI retrievals of dust AOT are compared with those from the coincident/collocated multifilter rotating shadow-band radiometer (MFRSR), micropulse lidar (MPL), and NASA Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) sensors. The retrieved AOTs are then inputted into the Fu-Liou 1D radiative transfer model to evaluate local instantaneous direct longwave radiative effects (DRE(sub LW)) of dust at the surface in cloud-free atmospheres and its sensitivity to dust microphysical parameters. The top-of-atmosphere DRE(sub LW) and longwave heating rate profiles are also evaluated. Instantaneous surface DRE(sub LW) ranges from 2 to 10 W/sq m and exhibits a strong linear dependence with dust AOT yielding a DRE(sub LW) of 16 W/sq m per unit dust AOT. The DRE(sub LW) is estimated to be approx.42% of the diurnally averaged direct shortwave radiative effect at the surface but of opposite sign, partly compensating for the shortwave losses. Certainly nonnegligible, the authors conclude that DRE(sub LW) can significantly impact the atmospheric energetics, representing an important component in the study of regional climate variation.

  6. Nitrogen dioxide observations from the Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) airborne instrument: retrieval algorithm and measurements during DISCOVER-AQ Texas 2013

    NASA Astrophysics Data System (ADS)

    Nowlan, C. R.; Liu, X.; Leitch, J. W.; Chance, K.; González Abad, G.; Liu, C.; Zoogman, P.; Cole, J.; Delker, T.; Good, W.; Murcray, F.; Ruppert, L.; Soo, D.; Follette-Cook, M. B.; Janz, S. J.; Kowalewski, M. G.; Loughner, C. P.; Pickering, K. E.; Herman, J. R.; Beaver, M. R.; Long, R. W.; Szykman, J. J.; Judd, L. M.; Kelley, P.; Luke, W. T.; Ren, X.; Al-Saadi, J. A.

    2015-12-01

    The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) airborne instrument is a testbed for upcoming air quality satellite instruments that will measure backscattered ultraviolet, visible and near-infrared light from geostationary orbit. GeoTASO flew on the NASA Falcon aircraft in its first intensive field measurement campaign during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) Earth Venture Mission over Houston, Texas in September 2013. Measurements of backscattered solar radiation between 420-465 nm collected on four days during the campaign are used to determine slant column amounts of NO2 at 250 m × 250 m spatial resolution with a fitting precision of 2.2 × 1015 molecules cm-2. These slant columns are converted to tropospheric NO2 vertical columns using a radiative transfer model and trace gas profiles from the Community Multiscale Air Quality (CMAQ) model. Total column NO2 from GeoTASO is well correlated with ground-based Pandora observations (r = 0.90 on the most polluted and cloud-free day of measurements), with GeoTASO NO2 slightly higher for the most polluted observations. Surface NO2 mixing ratios inferred from GeoTASO using the CMAQ model show good correlation with NO2 measured in situ at the surface during the campaign (r = 0.91 for the most polluted day). NO2 slant columns from GeoTASO also agree well with preliminary retrievals from the GEO-CAPE Airborne Simulator (GCAS) which flew on the NASA King Air B200 (r = 0.84, slope = 0.94). Enhanced NO2 is resolvable over areas of traffic NOx emissions and near individual petrochemical facilities.

  7. Nitrogen dioxide observations from the Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) airborne instrument: Retrieval algorithm and measurements during DISCOVER-AQ Texas 2013

    NASA Astrophysics Data System (ADS)

    Nowlan, Caroline R.; Liu, Xiong; Leitch, James W.; Chance, Kelly; González Abad, Gonzalo; Liu, Cheng; Zoogman, Peter; Cole, Joshua; Delker, Thomas; Good, William; Murcray, Frank; Ruppert, Lyle; Soo, Daniel; Follette-Cook, Melanie B.; Janz, Scott J.; Kowalewski, Matthew G.; Loughner, Christopher P.; Pickering, Kenneth E.; Herman, Jay R.; Beaver, Melinda R.; Long, Russell W.; Szykman, James J.; Judd, Laura M.; Kelley, Paul; Luke, Winston T.; Ren, Xinrong; Al-Saadi, Jassim A.

    2016-06-01

    The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) airborne instrument is a test bed for upcoming air quality satellite instruments that will measure backscattered ultraviolet, visible and near-infrared light from geostationary orbit. GeoTASO flew on the NASA Falcon aircraft in its first intensive field measurement campaign during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) Earth Venture Mission over Houston, Texas, in September 2013. Measurements of backscattered solar radiation between 420 and 465 nm collected on 4 days during the campaign are used to determine slant column amounts of NO2 at 250 m × 250 m spatial resolution with a fitting precision of 2.2 × 1015 moleculescm-2. These slant columns are converted to tropospheric NO2 vertical columns using a radiative transfer model and trace gas profiles from the Community Multiscale Air Quality (CMAQ) model. Total column NO2 from GeoTASO is well correlated with ground-based Pandora observations (r = 0.90 on the most polluted and cloud-free day of measurements and r = 0.74 overall), with GeoTASO NO2 slightly higher for the most polluted observations. Surface NO2 mixing ratios inferred from GeoTASO using the CMAQ model show good correlation with NO2 measured in situ at the surface during the campaign (r = 0.85). NO2 slant columns from GeoTASO also agree well with preliminary retrievals from the GEO-CAPE Airborne Simulator (GCAS) which flew on the NASA King Air B200 (r = 0.81, slope = 0.91). Enhanced NO2 is resolvable over areas of traffic NOx emissions and near individual petrochemical facilities.

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  9. The airborne mass spectrometer AIMS - Part 2: Measurements of trace gases with stratospheric or tropospheric origin in the UTLS

    NASA Astrophysics Data System (ADS)

    Jurkat, T.; Kaufmann, S.; Voigt, C.; Schäuble, D.; Jeßberger, P.; Ziereis, H.

    2015-12-01

    Understanding the role of climate-sensitive trace gas variabilities in the upper troposphere and lower stratosphere region (UTLS) and their impact on its radiative budget requires accurate measurements. The composition of the UTLS is governed by transport and chemistry of stratospheric and tropospheric constituents, such as chlorine, nitrogen oxide and sulphur components. The Airborne chemical Ionization Mass Spectrometer AIMS has been developed to accurately measure a set of these constituents on aircraft by means of chemical ionization. Here we present a setup using chemical ionization with SF5- reagent ions for the simultaneous measurement of trace gas concentrations in the pptv to ppmv (10-12 to 10-6 mol mol-1) range of HCl, HNO3 and SO2 with in-flight and online calibration called AIMS-TG. Part 1 of this paper (Kaufmann et al., 2015) reports on the UTLS water vapour measurements with the AIMS-H2O configuration. The instrument can be flexibly switched between two configurations depending on the scientific objective of the mission. For AIMS-TG, a custom-made gas discharge ion source has been developed generating a characteristic ionization scheme. HNO3 and HCl are routinely calibrated in-flight using permeation devices, SO2 is permanently calibrated during flight adding an isotopically labelled 34SO2 standard. In addition, we report on trace gas measurements of HONO which is sensitive to the reaction with SF5-. The detection limit for the various trace gases is in the low ten pptv range at a 1 s time resolution with an overall uncertainty of the measurement in the order of 20 %. AIMS has been integrated and successfully operated on the DLR research aircraft Falcon and HALO. Exemplarily, measurements conducted during the TACTS/ESMVal mission with HALO in 2012 are presented, focusing on a classification of tropospheric and stratospheric influences in the UTLS region. Comparison of AIMS measurements with other measurement techniques allow to draw a comprehensive

  10. Wind-Driven Angular Dependence of Sea-Surface Reflectance Measured with an Airborne Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Tratt, David M.; Menzies, Robert T.; Cutten, Dean R.

    1998-01-01

    The effects of wind-stress on the optical properties of the ocean surface have been studied for several decades. In particular, the classic study by Cox and Munk (1954) linking sea-surface wind field to wave slope statistics provides a phenomenology by which the sea-surface wind velocity can be estimated from direct measurement of the wave-modulated surface reflectance. A limited number of studies along these lines have been conducted using airborne or spaceborne lidar systems. In these instances, truthing was provided by in situ ship reports or satellite microwave remote sensing instruments (e.g., ERS scatterometer, SSM/I). During the second deployment of the MACAWS Doppler wind lidar in the summer of 1996 measurements of sea-surface reflectance as a function of azimuth- and nadir-viewing angles were acquired off the California coast. MACAWS data products include directly measured winds, as well as calibrated backscatter/reflectance profiles, thus enabling comparison of the winds inferred from sea-surface reflectance measurements with those deriving from the Doppler-processed direct line-of-sight (LOS) estimates. Additional validation data was extracted from the ERS and SSM/I satellite microwave sensor archives maintained by the JPL Physical Oceanography Distributed Active Archive Center (PO- DAAC).

  11. Validation of Temperature Measurements from the Airborne Raman Ozone Temperature and Aerosol Lidar During SOLVE

    NASA Technical Reports Server (NTRS)

    Burris, John; McGee, Thomas; Hoegy, Walter; Lait, Leslie; Twigg, Laurence; Sumnicht, Grant; Heaps, William; Hostetler, Chris; Bui, T. Paul; Neuber, Roland; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    The Airborne Raman Ozone, Temperature and Aerosol Lidar (AROTEL) participated in the recent Sage III Ozone Loss and Validation Experiment (SOLVE) by providing profiles of aerosols, polar stratospheric clouds (PSCs), ozone and temperature with high vertical and horizontal resolution. Temperatures were derived from just above the aircraft to approximately 60 kilometers geometric altitude with a reported vertical resolution of between 0.5 and 1.5 km. The horizontal footprint varied from 4 to 70 km. This paper explores the measurement uncertainties associated with the temperature retrievals and makes comparisons with independent, coincident, measurements of temperature. Measurement uncertainties range from 0.1 K to approximately 4 K depending on altitude and integration time. Comparisons between AROTEL and balloon sonde temperatures retrieved under clear sky conditions using both Rayleigh and Raman scattered data showed AROTEL approximately 1 K colder than sonde values. Comparisons between AROTEL and the Meteorological Measurement System (MMS) on NASA's ER-2 show AROTEL being from 2-3 K colder for altitudes ranging from 14 to 18 km. Temperature comparisons between AROTEL and the United Kingdom Meteorological Office's model showed differences of approximately 1 K below approximately 25 km and a very strong cold bias of approximately 12 K at altitudes between 30 and 35 km.

  12. Atmospheric Airborne Pressure Measurements using the Oxygen A Band for the ASCENDS Mission

    NASA Astrophysics Data System (ADS)

    Riris, H.; Rodriguez, M.

    2014-12-01

    We report on an airborne demonstration of atmospheric oxygen optical depth measurements with an Integrated Path Differential Absorption (IPDA) lidar using a fiber-based laser system and a photon counting detector. Accurate knowledge of atmospheric temperature and pressure is required for NASA's Active Sensing of CO2 Emissions over Nights, Days and Seasons (ASCENDS) space mission, and climate modeling studies. The lidar uses a doubled Erbium Doped Fiber amplifier and single photon counting detector to measure oxygen absorption at 765 nm. Our approach uses a sequence of laser pulses at increasing wavelengths that sample a pair of absorption lines in the Oxygen A-band at 764.7 nm. The O2 lines were selected after careful spectroscopic analysis to minimize the O2 line temperature dependence and the availability of the transmitter and receiver technology to maximize transmitter power, doubling efficiency, and detector sensitivity. We compare our 2013 and 2014 Oxygen IPDA lidar measurements and evaluate the impact of receiver dynamic range, transmitter stability and signal to noise ratio on the differential optical depth measurements.

  13. Methods of and apparatus for radiation measurement, and specifically for in vivo radiation measurement

    DOEpatents

    Huffman, D.D.; Hughes, R.C.; Kelsey, C.A.; Lane, R.; Ricco, A.J.; Snelling, J.B.; Zipperian, T.E.

    1986-08-29

    Methods of and apparatus for in vivo radiation measurements rely on a MOSFET dosimeter of high radiation sensitivity which operates in both the passive mode to provide an integrated dose detector and active mode to provide an irradiation rate detector. A compensating circuit with a matched unirradiated MOSFET is provided to operate at a current designed to eliminate temperature dependence of the device. Preferably, the MOSFET is rigidly mounted in the end of a miniature catheter and the catheter is implanted in the patient proximate the radiation source.

  14. Measurement of Thermal Radiation Properties of Solids

    NASA Technical Reports Server (NTRS)

    Richmond, J. C. (Editor)

    1963-01-01

    The overall objectives of the Symposium were to afford (1) an opportunity for workers in the field to describe the equipment and procedures currently in use for measuring thermal radiation properties of solids, (2) an opportunity for constructive criticism of the material presented, and (3) an open forum for discussion of mutual problems. It was also the hope of the sponsors that the published proceedings of the Symposium would serve as a valuable reference on measurement techniques for evaluating thermal radiation properties of solids, partic.ularly for those with limited experience in the field. Because of the strong dependence of emitted flux upon temperature, the program committee thought it advisable to devote the first session to a discussion of the problems of temperature measurement. All of the papers in Session I were presented at the request of and upon topics suggested by the Committee. Because of time and space limitations, it, was impossible to consider all temperature measurement problems that might arise--the objective was rather to call to the attention of the reader some of the problems that might be encountered, and to provide references that might provide solutions.

  15. Airborne Sun Photometer Measurements of Aerosol Optical Depth during SOLVE II: Comparison with SAGE III and POAM III Measurements

    NASA Technical Reports Server (NTRS)

    Russell, P.; Livingston, J.; Schmid, B.; Eilers, J.; Kolyer, R.; Redemann, J.; Yee, J.-H.; Trepte, C.; Thomason, L.; Zawodny, J.

    2003-01-01

    The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was operated aboard the NASA DC-8 during the Second SAGE III Ozone Loss and Validation Experiment (SOLVE II) and obtained successful measurements during the sunlit segments of eight science flights. These included six flights out of Kiruna, Sweden, one flight out of NASA Dryden Flight Research Center (DFRC), and the Kiruna-DFRC return transit flight. Values of spectral aerosol optical depth (AOD), columnar ozone and columnar water vapor have been derived from the AATS-14 measurements. In this paper, we focus on AATS-14 AOD data. In particular, we compare AATS-14 AOD spectra with temporally and spatially near-coincident measurements by the Stratospheric Aerosol and Gas Experiment III (SAGE III) and the Polar Ozone and Aerosol Measurement III (POAM III) satellite sensors. We examine the effect on retrieved AOD of uncertainties in relative optical airmass (the ratio of AOD along the instrument-to-sun slant path to that along the vertical path) at large solar zenith angles. Airmass uncertainties result fiom uncertainties in requisite assumed vertical profiles of aerosol extinction due to inhomogeneity along the viewing path or simply to lack of available data. We also compare AATS-14 slant path solar transmission measurements with coincident measurements acquired from the DC-8 by the NASA Langley Research Center Gas and Aerosol Measurement Sensor (GAMS).

  16. Photocatalytic Active Radiation Measurements and Use

    NASA Technical Reports Server (NTRS)

    Davis, Bruce A.; Underwood, Lauren W.

    2011-01-01

    Photocatalytic materials are being used to purify air, to kill microbes, and to keep surfaces clean. A wide variety of materials are being developed, many of which have different abilities to absorb various wavelengths of light. Material variability, combined with both spectral illumination intensity and spectral distribution variability, will produce a wide range of performance results. The proposed technology estimates photocatalytic active radiation (PcAR), a unit of radiation that normalizes the amount of light based on its spectral distribution and on the ability of the material to absorb that radiation. Photocatalytic reactions depend upon the number of electron-hole pairs generated at the photocatalytic surface. The number of electron-hole pairs produced depends on the number of photons per unit area per second striking the surface that can be absorbed and whose energy exceeds the bandgap of the photocatalytic material. A convenient parameter to describe the number of useful photons is the number of moles of photons striking the surface per unit area per second. The unit of micro-einsteins (or micromoles) of photons per m2 per sec is commonly used for photochemical and photoelectric-like phenomena. This type of parameter is used in photochemistry, such as in the conversion of light energy for photosynthesis. Photosynthetic response correlates with the number of photons rather than by energy because, in this photochemical process, each molecule is activated by the absorption of one photon. In photosynthesis, the number of photons absorbed in the 400 700 nm spectral range is estimated and is referred to as photosynthetic active radiation (PAR). PAR is defined in terms of the photosynthetic photon flux density measured in micro-einsteins of photons per m2 per sec. PcAR is an equivalent, similarly modeled parameter that has been defined for the photocatalytic processes. Two methods to measure the PcAR level are being proposed. In the first method, a calibrated

  17. Spatially explicit modelling of forest structure and function using airborne lidar and hyperspectral remote sensing data combined with micrometeorological measurements

    NASA Astrophysics Data System (ADS)

    Thomas, Valerie Anne

    This research models canopy-scale photosynthesis at the Groundhog River Flux Site through the integration of high-resolution airborne remote sensing data and micrometeorological measurements collected from a flux tower. Light detection and ranging (lidar) data are analysed to derive models of tree structure, including: canopy height, basal area, crown closure, and average aboveground biomass. Lidar and hyperspectral remote sensing data are used to model canopy chlorophyll (Chl) and carotenoid concentrations (known to be good indicators of photosynthesis). The integration of lidar and hyperspectral data is applied to derive spatially explicit models of the fraction of photosynthetically active radiation (fPAR) absorbed by the canopy as well as a species classification for the site. These products are integrated with flux tower meteorological measurements (i.e., air temperature and global solar radiation) collected on a continuous basis over 2004 to apply the C-Fix model of carbon exchange to the site. Results demonstrate that high resolution lidar and lidar-hyperspectral integration techniques perform well in the boreal mixedwood environment. Lidar models are well correlated with forest structure, despite the complexities introduced in the mixedwood case (e.g., r2=0.84, 0.89, 0.60, and 0.91, for mean dominant height, basal area, crown closure, and average aboveground biomass). Strong relationships are also shown for canopy scale chlorophyll/carotenoid concentration analysis using integrated lidar-hyperspectral techniques (e.g., r2=0.84, 0.84, and 0.82 for Chl(a), Chl(a+b), and Chl(b)). Examination of the spatially explicit models of fPAR reveal distinct spatial patterns which become increasingly apparent throughout the season due to the variation in species groupings (and canopy chlorophyll concentration) within the 1 km radius surrounding the flux tower. Comparison of results from the modified local-scale version of the C-Fix model to tower gross ecosystem

  18. Retrieval of Atmospheric CO2 Concentration above Clouds and Cloud Top Pressure from Airborne Lidar Measurements during ASCENDS Science Campaigns

    NASA Astrophysics Data System (ADS)

    Mao, J.; Ramanathan, A. K.; Rodriguez, M.; Allan, G. R.; Hasselbrack, W. E.; Abshire, J. B.; Riris, H.; Kawa, S. R.

    2014-12-01

    NASA Goddard is developing an integrated-path, differential absorption (IPDA) lidar approach to measure atmospheric CO2 concentrations from space as a candidate for NASA's ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) mission. The approach uses pulsed lasers to measure both CO2 and O2 absorption simultaneously in the vertical path to the surface at a number of wavelengths across a CO2 line at 1572.335 nm and an O2 line doublet near 764.7 nm. Measurements of time-resolved laser backscatter profiles from the atmosphere allow the technique to estimate column CO2 and O2 number density and range to cloud tops in addition to those to the ground. This allows retrievals of CO2 column above clouds and cloud top pressure, and all-sky measurement capability from space. This additional information can be used to evaluate atmospheric transport processes and other remote sensing carbon data in the free atmosphere, improve carbon data assimilation in models and help global and regional carbon flux estimates. We show some preliminary results of this capability using airborne lidar measurements from the summers of 2011 and 2014 ASCENDS science campaigns. These show simultaneous retrievals of CO2 and O2 column densities for laser returns from low-level marine stratus clouds in the west coast of California. This demonstrates the supplemental capability of the future space carbon mission to measure CO2 above clouds, which is valuable particularly for the areas with persistent cloud covers, e.g, tropical ITCZ, west coasts of continents with marine layered clouds and southern ocean with highest occurrence of low-level clouds, where underneath carbon cycles are active but passive remote sensing techniques using the reflected short wave sunlight are unable to measure accurately due to cloud scattering effect. We exercise cloud top pressure retrieval from O2 absorption measurements during the flights over the low-level marine stratus cloud decks, which is one of

  19. Airborne Measurements of CO2 Exchange above a Heterogeneous Northern-latitude Forest

    NASA Astrophysics Data System (ADS)

    Salmon, O. E.; Caulton, D.; Shepson, P. B.; Stirm, B. H.; Metzger, S.; Musinsky, J.; Munger, J. W.

    2014-12-01

    Northern latitude forests represent an important global sink for carbon dioxide (CO2). Estimating the landscape-scale exchange of CO2 is complicated by the heterogeneity of forested areas. Airborne eddy-covariance measurements can complement continuous tower-based measurements for determining the magnitude and spatial variability of carbon uptake in forested areas, and to assess means for scaling-up. While aircraft provide accessibility, the resulting flux measurements represent a narrow time slice, and average over a comparatively large source area. The goal of this study is to improve our ability to attribute aircraft flux data to finer spatial scales. We hypothesize that this can be achieved by (i) improving the spatial scale of the sampling method, (ii) examining inter-day variability, and (iii) relating airborne eddy-covariance flux estimates to remote sensing determinations of the land cover. For this purpose identical flight experiments were conducted on May 29 and June 1, 2014 over a 240 km2 region encompassing the Harvard University EMS eddy flux tower at Harvard Forest, MA, using the Purdue University ALAR aircraft. In the early afternoon of each day, 19 flight legs, 20 km in length, were flown over the heterogeneous forest canopy. The two replicate experiments allow assessment of inter-day variability in CO2 exchange under similar meteorological conditions. Furthermore, the experiments were coordinated with high-resolution (≤1 m) and medium-resolution (≤100 m) remote sensing retrievals of forest canopy structure and composition (NEON AOP) and soil moisture (NASA AirMOSS), respectively. This unprecedented hierarchy of observations enables evaluation of the ability of different data processing approaches to calculate finer scale CO2 exchange with the surface. Analyses of the flights conducted on May 29 and June 1 show a transect-averaged (± 1σ) CO2 uptake of 13 ± 3 µmol m-2s-1 and 11 ± 2 µmol m-2s-1, respectively. In complement to the aircraft

  20. 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

  1. First Airborne Lidar Measurements of Methane and Carbon Dioxide Applying the MERLIN Demonstrator CHARM-F

    NASA Astrophysics Data System (ADS)

    Amediek, Axel; Büdenbender, Christian; Ehret, Gerhard; Fix, Andreas; Gerbig, Christoph; Kiemle, Chritstoph; Quatrevalet, Mathieu; Wirth, Martin

    2016-04-01

    CHARM-F is the new airborne four-wavelengths lidar for simultaneous soundings of atmospheric CO2 and CH4. Due to its high technological conformity it is also a demonstrator for MERLIN, the French-German satellite mission providing a methane lidar. MERLIN's Preliminary Design Review was successfully passed recently. The launch is planned for 2020. First CHARM-F measurements were performed in Spring 2015 onboard the German research aircraft HALO. The aircraft's maximum flight altitude of 15 km and special features of the lidar, such as a relatively large laser ground spot, result in data similar to those obtained by a spaceborne system. The CHARM-F and MERLIN lidars are designed in the IPDA (integrated path differential absorption) configuration using short double pulses, which gives column averaged gas mixing ratios between the system and ground. The successfully completed CHARM-F flight measurements provide a valuable dataset, which supports the retrieval algorithm development for MERLIN notably. Furthermore, the dataset allows detailed analyses of measurement sensitivities, general studies on the IPDA principle and on system design questions. These activities are supported by another instrument onboard the aircraft during the flight campaign: a cavity ring down spectrometer, providing in-situ data of carbon dioxide, methane and water vapor with high accuracy and precision, which is ideal for validation purposes of the aircraft lidar. For the near future, detailed characterizations of CHARM-F are planned, further support of the MERLIN design, as well as the scientific aircraft campaign CoMet.

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

    NASA Astrophysics Data System (ADS)

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

    2007-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-02-01

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

  4. Measurement techniques for respiratory tract deposition of airborne nanoparticles: a critical review.

    PubMed

    Löndahl, Jakob; Möller, Winfried; Pagels, Joakim H; Kreyling, Wolfgang G; Swietlicki, Erik; Schmid, Otmar

    2014-08-01

    Determination of the respiratory tract deposition of airborne particles is critical for risk assessment of air pollution, inhaled drug delivery, and understanding of respiratory disease. With the advent of nanotechnology, there has been an increasing interest in the measurement of pulmonary deposition of nanoparticles because of their unique properties in inhalation toxicology and medicine. Over the last century, around 50 studies have presented experimental data on lung deposition of nanoparticles (typical diameter≤100 nm, but here≤300 nm). These data show a considerable variability, partly due to differences in the applied methodologies. In this study, we review the experimental techniques for measuring respiratory tract deposition of nano-sized particles, analyze critical experimental design aspects causing measurement uncertainties, and suggest methodologies for future studies. It is shown that, although particle detection techniques have developed with time, the overall methodology in respiratory tract deposition experiments has not seen similar progress. Available experience from previous research has often not been incorporated, and some methodological design aspects that were overlooked in 30-70% of all studies may have biased the experimental data. This has contributed to a significant uncertainty on the absolute value of the lung deposition fraction of nanoparticles. We estimate the impact of the design aspects on obtained data, discuss solutions to minimize errors, and highlight gaps in the available experimental set of data.

  5. Airborne validation of cirrus cloud properties derived from CALIPSO lidar measurements: Optical properties

    NASA Astrophysics Data System (ADS)

    Hlavka, Dennis L.; Yorks, John E.; Young, Stuart A.; Vaughan, Mark A.; Kuehn, Ralph E.; McGill, Matthew J.; Rodier, Sharon D.

    2012-05-01

    The Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) satellite was successfully launched in April 2006 to study cloud and aerosol layers using range-resolved laser remote sensing. Dedicated flights were conducted from July 26 to August 14, 2006 using the airborne Cloud Physics Lidar (CPL) to validate the CALIPSO lidar (CALIOP) data products. This paper presents results from coincident ice cloud measurements of lidar ratio, extinction coefficient, and optical depth. Flight segment case studies are shown as well as statistics for all coincident measurements during this CALIPSO-CloudSat Validation Experiment (CC-VEX). For the penetrated portion of opaque layers, CALIOP estimates of lidar ratio and extinction are substantially lower than the corresponding CPL values. Significant differences were also found for measurements of horizontally aligned ice, where different instrument viewing geometries precluded meaningful comparisons. After filtering the data set to exclude these discrepancies, overall CALIOP lidar ratio and extinction averages compared favorably to within 1% of overall CPL averages. When restricting the data further to exact coincident in-cloud point-pairs, CALIOP lidar ratios remained close to CPL values, averaging 2.1% below CPL, and the retrieved extinction and optical depth averaged 14.7% above CPL values, a result partially of higher average CALIOP attenuated backscatter but still a respectably close match.

  6. Airborne validation of cirrus cloud properties derived from CALIPSO lidar measurements: Spatial properties

    NASA Astrophysics Data System (ADS)

    Yorks, John E.; Hlavka, Dennis L.; Vaughan, Mark A.; McGill, Matthew J.; Hart, William D.; Rodier, Sharon; Kuehn, Ralph

    2011-10-01

    The Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) satellite was successfully launched in 2006 and has provided an unprecedented opportunity to study cloud and aerosol layers using range-resolved laser remote sensing. Dedicated validation flights were conducted using the airborne Cloud Physics Lidar (CPL) to validate the CALIPSO Level 1 and 2 data products. This paper presents results from coincident CALIPSO and CPL measurements of ice cloud spatial properties. Flight segment case studies are shown as well as statistics for all coincident measurements during the CALIPSO-CloudSat Validation Experiment (CC-VEX). CALIPSO layer detection algorithms for cirrus clouds are reliable in comparison with CPL, with best agreement occurring during nighttime coincident segments when the signal-to-noise ratio (SNR) of both instruments is greatest. However, the two instruments disagree on ice cloud spatial properties in two distinct cases. CALIPSO experiences less sensitivity to optically thin cirrus due to lower SNR when compared to CPL data at identical spatial scales. The incorporation of extended spatial averaging in the CALIPSO layer detection algorithm succeeds in detecting the optically thin cirrus, but the averaging process occasionally results in spatial smearing, both horizontally and vertically, of broken cirrus clouds. The second disparity occurs because, in contrast to CPL, multiple scattering contributes significantly to CALIPSO lidar measurements of cirrus clouds. As a result, the CALIPSO signal penetrates deeper into opaque cirrus clouds, and in these cases CALIPSO will report lower apparent cloud base altitudes than CPL.

  7. 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.

  8. Aerosol optical properties in the ABL over arctic sea ice from airborne aerosol lidar measurements

    NASA Astrophysics Data System (ADS)

    Schmidt, Lukas; Neuber, Roland; Ritter, Christoph; Maturilli, Marion; Dethloff, Klaus; Herber, Andreas

    2014-05-01

    Between 2009 and 2013 aerosols, sea ice properties and meteorological variables were measured during several airborne campaigns covering a wide range of the western Arctic Ocean. The campaigns were carried out with the aircraft Polar 5 of the German Alfred-Wegener-Institute (AWI) during spring and summer periods. Optical properties of accumulation mode aerosol and clouds were measured with the nadir looking AMALi aerosol lidar covering the atmospheric boundary layer and the free troposphere up to 3000m, while dropsondes provided coincident vertical profiles of meteorological quantities. Based on these data we discuss the vertical distribution of aerosol backscatter in and above the atmospheric boundary layer and its dependence on relative humidity, dynamics and underlying sea ice properties. We analyze vertical profiles of lidar and coincident dropsonde measurements from various locations in the European and Canadian Arctic from spring and summer campaigns. Sea ice cover is derived from modis satellite and aircraft onboard camera images. The aerosol load in the arctic atmospheric boundary layer shows a high variability. Various meteorological parameters and in particular boundary layer properties are discussed with their respective influence on aerosol features. To investigate the effect of the frequency and size of open water patches on aerosol properties, we relate the profiles to the sea ice properties influencing the atmosphere in the upwind region.

  9. Measurement Techniques for Respiratory Tract Deposition of Airborne Nanoparticles: A Critical Review

    PubMed Central

    Möller, Winfried; Pagels, Joakim H.; Kreyling, Wolfgang G.; Swietlicki, Erik; Schmid, Otmar

    2014-01-01

    Abstract Determination of the respiratory tract deposition of airborne particles is critical for risk assessment of air pollution, inhaled drug delivery, and understanding of respiratory disease. With the advent of nanotechnology, there has been an increasing interest in the measurement of pulmonary deposition of nanoparticles because of their unique properties in inhalation toxicology and medicine. Over the last century, around 50 studies have presented experimental data on lung deposition of nanoparticles (typical diameter≤100 nm, but here≤300 nm). These data show a considerable variability, partly due to differences in the applied methodologies. In this study, we review the experimental techniques for measuring respiratory tract deposition of nano-sized particles, analyze critical experimental design aspects causing measurement uncertainties, and suggest methodologies for future studies. It is shown that, although particle detection techniques have developed with time, the overall methodology in respiratory tract deposition experiments has not seen similar progress. Available experience from previous research has often not been incorporated, and some methodological design aspects that were overlooked in 30–70% of all studies may have biased the experimental data. This has contributed to a significant uncertainty on the absolute value of the lung deposition fraction of nanoparticles. We estimate the impact of the design aspects on obtained data, discuss solutions to minimize errors, and highlight gaps in the available experimental set of data. PMID:24151837

  10. Radiated microwave power transmission system efficiency measurements

    NASA Technical Reports Server (NTRS)

    Dickinson, R. M.; Brown, W. C.

    1975-01-01

    The measured and calculated results from determining the operating efficiencies of a laboratory version of a system for transporting electric power from one point to another via a wireless free space radiated microwave beam are reported. The system's overall end-to-end efficiency as well as intermediated conversion efficiencies were measured. The maximum achieved end-to-end dc-to-ac system efficiency was 54.18% with a probable error of + or - 0.94%. The dc-to-RF conversion efficiency was measured to be 68.87% + or - 1.0% and the RF-to-dc conversion efficiency was 78.67 + or - 1.1%. Under these conditions a dc power of 495.62 + or - 3.57 W was received with a free space transmitter antenna receiver antenna separation of 170.2 cm (67 in).

  11. Evaluation of an airborne triple-pulsed 2 μm IPDA lidar for simultaneous and independent atmospheric water vapor and carbon dioxide measurements.

    PubMed

    Refaat, Tamer F; Singh, Upendra N; Yu, Jirong; Petros, Mulugeta; Ismail, Syed; Kavaya, Michael J; Davis, Kenneth J

    2015-02-20

    Water vapor and carbon dioxide are the most dominant greenhouse gases directly contributing to the Earth's radiation budget and global warming. A performance evaluation of an airborne triple-pulsed integrated path differential absorption (IPDA) lidar system for simultaneous and independent monitoring of atmospheric water vapor and carbon dioxide column amounts is presented. This system leverages a state-of-the-art Ho:Tm:YLF triple-pulse laser transmitter operating at 2.05 μm wavelength. The transmitter provides wavelength tuning and locking capabilities for each pulse. The IPDA lidar system leverages a low risk and technologically mature receiver system based on InGaAs pin detectors. Measurement methodology and wavelength setting are discussed. The IPDA lidar return signals and error budget are analyzed for airborne operation on-board the NASA B-200. Results indicate that the IPDA lidar system is capable of measuring water vapor and carbon dioxide differential optical depth with 0.5% and 0.2% accuracy, respectively, from an altitude of 8 km to the surface and with 10 s averaging. Provided availability of meteorological data, in terms of temperature, pressure, and relative humidity vertical profiles, the differential optical depth conversion into weighted-average column dry-air volume-mixing ratio is also presented.

  12. Identification of Lightning Gaps in Mangrove Forests Using Airborne LIDAR Measurements

    NASA Astrophysics Data System (ADS)

    Zhang, K.

    2006-12-01

    Mangrove forests are highly dynamic ecosystems and change frequently due to tropical storms, frost, and lightning. These factors can cause gaps in mangrove forests by damaging trees. Compared to gaps generated by storms and frost, gaps caused by lightning strikes are small, ranging from 50 to 300 m2. However, these small gaps may play a critical role in mangrove forest dynamics because of the frequent occurrence of lightning in tropical areas. It has been hypothesized that the turnover of mangrove forests is mainly due to the death and regeneration of trees in lightning gaps. However, there is a lack of data for gap occurrence in mangrove forests to verify this hypothesis. It is impractical to measure gaps through a field survey on a large scale because of the logistic difficulties of muddy mangrove forests. Airborne light detection and ranging (LIDAR) technology is an effective alternative because it provides direct measurements of ground and canopy elevations remotely. This study developed a method to identify lightning gaps in mangrove forests in terms of LIDAR measurements. First, LIDAR points are classified into vegetation and ground measurements using the progressive morphological filter. Second, a digital canopy model (DCM) is generated by subtracting a digital terrain model (DTM) from a digital surface model (DSM). The DSM is generated by interpolating raw LIDAR measurements, and DTM is produced by interpolating ground measurements. Third, a black top-hat mathematical morphological transformation is used to identify canopy gaps. Comparison of identified gap polygons with raw LIDAR measurements and field surveys shows that the proposed method identifies lightning gaps in mangrove forests successfully. The area of lightning gaps in mangrove forests in Everglades National Park is about 3% of total forest area, which verifies that lightning gaps play a critical role in mangrove forest turnover.

  13. Airborne Dust Cloud Measurements at the INL National Security Test Range

    SciTech Connect

    Michael L. Abbott; Norm Stanley; Larry Radke; Charles Smeltzer

    2007-09-01

    On July 11, 2007, a surface, high-explosive test (<20,000 lb TNT-equivalent) was carried out at the National Security Test Range (NSTR) on the Idaho National Laboratory (INL) Site. Aircraft-mounted rapid response (1-sec) particulate monitors were used to measure airborne PM-10 concentrations directly in the dust cloud and to develop a PM-10 emission factor that could be used for subsequent tests at the NSTR. The blast produced a mushroom-like dust cloud that rose approximately 2,500–3,000 ft above ground level, which quickly dissipated (within 5 miles of the source). In general, the cloud was smaller and less persistence than expected, or that might occur in other areas, likely due to the coarse sand and subsurface conditions that characterize the immediate NSTR area. Maximum short time-averaged (1-sec) PM-10 concentrations at the center of the cloud immediately after the event reached 421 µg m-3 but were rapidly reduced (by atmospheric dispersion and fallout) to near background levels (~10 µg m-3) after about 15 minutes. This occurred well within the INL Site boundary, about 8 km (5 miles) from the NSTR source. These findings demonstrate that maximum concentrations in ambient air beyond the INL Site boundary (closest is 11.2 km from NSTR) from these types of tests would be well within the 150 µg m-3 24-hour National Ambient Air Quality Standards for PM-10. Aircraft measurements and geostatistical techniques were used to successfully quantify the initial volume (1.64E+9 m3 or 1.64 km3) and mass (250 kg) of the PM-10 dust cloud, and a PM-10 emission factor (20 kg m-3 crater soil volume) was developed for this specific type of event at NSTR. The 250 kg of PM-10 mass estimated from this experiment is almost seven-times higher than the 36 kg estimated for the environmental assessment (DOE-ID 2007) using available Environmental Protection Agency (EPA 1995) emission factors. This experiment demonstrated that advanced aircraft-mounted instruments operated by

  14. Snow thickness retrieval using SMOS satellite data: Comparison with airborne IceBridge and buoy measurements

    NASA Astrophysics Data System (ADS)

    Maaß, N.; Kaleschke, L.; Tian-Kunze, X.

    2015-12-01

    The passive microwave mission SMOS (Soil Moisture and Ocean Salinity) provides daily coverage of the polar regions and its data have been used to retrieve thin sea ice thickness up to about one meter. In addition, there has been an attempt to retrieve snow thickness over thick Arctic multi-year ice, which is a crucial parameter for the freeboard-based estimation of (thick) sea ice thickness from lidar and radar altimetry. SMOS provides measurements at a frequency of 1.4 GHz (L-band) at horizontal and vertical polarization for a range of incidence angles (0 to 60°). The retrieval of ice or snow parameters from SMOS measurements is based on an emission model that describes the 1.4 GHz brightness temperature of (snow-covered) sea ice as a function of the ice and snow thicknesses and the permittivities of these media, which are mainly determined by ice temperature and salinity and snow density, respectively. In the first attempts to retrieve snow thickness from SMOS data, these parameters were assumed to be constant in the emission model, and the resulting maps were compared with airborne ice and snow thickness measurements taken during NASA's Operation IceBridge mission in spring 2012. The present approach to produce SMOS snow thickness maps is more elaborate. For example, available information on the ice surface temperature from MODIS (MODerate resolution Imaging Spectroradiometer) satellite images or from the IceBridge campaign itself are used, and the ice in the retrieval model is described by temperature and salinity profiles instead of using bulk values. As a first step we have produced (winter/spring) snow thickness maps of the Arctic, from 3-day-averages up to monthly means, using the available SMOS data from 2010 on. Here, we show how our spatial snow thickness distributions compare with IceBridge campaign data in the western Arctic from spring 2011 to 2015. In addition, we show how the temporal evolution of SMOS-retrieved snow thickness compares with snow

  15. Radiated BPF sound measurement of centrifugal compressor

    NASA Astrophysics Data System (ADS)

    Ohuchida, S.; Tanaka, K.

    2013-12-01

    A technique to measure radiated BPF sound from an automotive turbocharger compressor impeller is proposed in this paper. Where there are high-level background noises in the measurement environment, it is difficult to discriminate the target component from the background. Since the effort of measuring BPF sound was taken in a room with such condition in this study, no discrete BPF peak was initially found on the sound spectrum. Taking its directionality into consideration, a microphone covered with a parabolic cone was selected and using this technique, the discrete peak of BPF was clearly observed. Since the level of measured sound was amplified due to the area-integration effect, correction was needed to obtain the real level. To do so, sound measurements with and without a parabolic cone were conducted for the fixed source and their level differences were used as correction factors. Consideration is given to the sound propagation mechanism utilizing measured BPF as well as the result of a simple model experiment. The present method is generally applicable to sound measurements conducted with a high level of background noise.

  16. Remote Measurements of Snowfalls in Wakasa Bay, Japan with Airborne Millimeter- wave Imaging Radiometer and Cloud Radar

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Austin, R.; Liu, G. S.; Racette, P. E.

    2004-01-01

    In this paper we explore the application of combined millimeter-wave radar and radiometry to remotely measure snowfall. During January-February of 2003, a field campaign was conducted with the NASA P-3 aircraft in Wakasa Bay, Japan for the validation of the AMSRE microwave radiometer on board the Aqua satellite. Among the suite of instruments-on board the P-3 aircraft were the Millimeter-wave Imaging Radiometer (MIR) from the NASA Goddard Space Flight Center and the 94 GHz Airborne Cloud Radar (ACR) which is co-owned and operated by NASA Jet Propulsion Laboratory/University of Massachusetts. MIR is a total power, across-track scanning radiometer that measures radiation at the frequencies of 89, 150, 183.3 +/- 1, 183.3 +/- 3, 183.3 +/-7, 220, and 340 GHz. The MIR has flown many successful missions since its completion in May 1992. ACR is a newer instrument and flew only a few times prior to the Wakasa Bay deployment. These two instruments which are particularly well suited for the detection of snowfall functioned normally during flights over snowfall and excellent data sets were acquired. On January 14, 28, and 29 flights were conducted over snowfall events. The MIR and ACR detected strong signals during periods of snowfall over ocean and land. Results from the analysis of these concurrent data sets show that (1) the scattering of millimeter-wave radiation as detected by the MIR is strongly correlated with ACR radar reflectivity profiles, and (2) the scattering is highly frequency-dependent, the higher the frequency the stronger the scattering. Additionally, the more transparent channels of the MIR (e.g., 89, 150, and 220 GHz) are found to display ambiguous signatures of snowfall because of their exposure to surface features. Thus, the snowfall detection and retrievals of snowfall parameters, such as the ice water path (IWP) and median mass diameter (D(me)) are best conducted at the more opaque channels near 183.3 GHz and 340 GHz. Retrievals of IWP and D(me) using

  17. Results of airborne measurements in the plume near and far from the 2014 Bardarbunga-Holuhraun eruption.

    NASA Astrophysics Data System (ADS)

    Arnason, Gylfi; Eliasson, Jonas; Weber, Konradin; Boehlke, Christoph; Palsson, Thorgeir; Rognvaldsson, Olafur; Thorsteinsson, Throstur; Platt, Ulrich; Tirpitz, Lukas; Jones, Roderic L.; Smith, Paul D.

    2015-04-01

    The Volcanic Ash Research (VAR) group is focused on airborne measurement of ash contamination to support safe air travel. In relations to the recent eruption, the group measured ash and several gaseous species in the plume 10-300 km from the volcano. The eruption emitted ash turned out to be mostly in the fine aerosol range (much less than 10 micrometers in diameter). Our highest measured concentrations were lower than 1 mg/m3 indicating that commercial air traffic was not threatened (greater than 2 mg/m3) by the ash contamination. But we measured sulfur dioxide (SO2 ) up to 90 mg/m3, which presented a potentially dangerous pollution problem. However, airborne measurements indicate that the sulfur concentration decays (probably due to scavenging) as the plume is carried by the wind from the volcano, which limits the area of immediate danger to the public. Here we present size distribution for particulate matter collected during flights, near and far from the crater at various times. The particle data is then compared with simultaneously collected sulfur dioxide data and the rate of decay of is estimated. Sulfur and particle concentration variations with height in the far plume are presented. Some airborne measurements for H2S, NO, NO2 and CO2 will also be presented. This includes correlation matrices for simultaneous measurements of these gases and comparison to National Air Quality Standards and background values.

  18. HONO emission and production determined from airborne measurements over the Southeast U.S.

    NASA Astrophysics Data System (ADS)

    Neuman, J. A.; Trainer, M.; Brown, S. S.; Min, K.-E.; Nowak, J. B.; Parrish, D. D.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Veres, P. R.

    2016-08-01

    The sources and distribution of tropospheric nitrous acid (HONO) were examined using airborne measurements over the Southeast U.S. during the Southeast Nexus Experiment in June and July 2013. HONO was measured once per second using a chemical ionization mass spectrometer on the NOAA WP-3D aircraft to assess sources that affect HONO abundance throughout the planetary boundary layer (PBL). The aircraft flew at altitudes between 0.12 and 6.4 km above ground level on 18 research flights that were conducted both day and night, sampling emissions from urban and power plant sources that were transported in the PBL. At night, HONO mixing ratios were greatest in plumes from agricultural burning, where they exceeded 4 ppbv and accounted for 2-14% of the reactive nitrogen emitted by the fires. The HONO to carbon monoxide ratio in these plumes from flaming stage fires ranged from 0.13 to 0.52%. Direct HONO emissions from coal-fired power plants were quantified using measurements at night, when HONO loss by photolysis was absent. These direct emissions were often correlated with total reactive nitrogen with enhancement ratios that ranged from 0 to 0.4%. HONO enhancements in power plant plumes measured during the day were compared with a Lagrangian plume dispersion model, showing that HONO produced solely from the gas phase reaction of OH with NO explained the observations. Outside of recently emitted plumes from known combustion sources, HONO mixing ratios measured several hundred meters above ground level were indistinguishable from zero within the 15 parts per trillion by volume measurement uncertainty. The results reported here do not support the existence of a ubiquitous unknown HONO source that produces significant HONO concentrations in the lower troposphere.

  19. 137Cs measurement uncertainties and detection limits for airborne gamma spectrometry (AGS) data analysed using a spectral windows method.

    PubMed

    Cresswell, A J; Sanderson, D C W; White, D C

    2006-02-01

    The uncertainties associated with airborne gamma spectrometry (AGS) measurements analysed using a spectral windows method, and associated detection limits, have been investigated. For individual short measurements over buried 137Cs activity detection limits of 10 kBq m(-2) are achieved. These detection limits are reduced for superficial activity and longer integration times. For superficial activity, detection limits below 1 kBq m(-2) are achievable. A comparison is made with the detection limits for other data processing methods.

  20. Taking Stock of Circumboreal Forest Carbon With Ground Measurements, Airborne and Spaceborne LiDAR

    NASA Technical Reports Server (NTRS)

    Neigh, Christopher S. R.; Nelson, Ross F.; Ranson, K. Jon; Margolis, Hank A.; Montesano, Paul M.; Sun, Guoqing; Kharuk, Viacheslav; Naesset, Erik; Wulder, Michael A.; Andersen, Hans-Erik

    2013-01-01

    The boreal forest accounts for one-third of global forests, but remains largely inaccessible to ground-based measurements and monitoring. It contains large quantities of carbon in its vegetation and soils, and research suggests that it will be subject to increasingly severe climate-driven disturbance. We employ a suite of ground-, airborne- and space-based measurement techniques to derive the first satellite LiDAR-based estimates of aboveground carbon for the entire circumboreal forest biome. Incorporating these inventory techniques with uncertainty analysis, we estimate total aboveground carbon of 38 +/- 3.1 Pg. This boreal forest carbon is mostly concentrated from 50 to 55degN in eastern Canada and from 55 to 60degN in eastern Eurasia. Both of these regions are expected to warm >3 C by 2100, and monitoring the effects of warming on these stocks is important to understanding its future carbon balance. Our maps establish a baseline for future quantification of circumboreal carbon and the described technique should provide a robust method for future monitoring of the spatial and temporal changes of the aboveground carbon content.

  1. Evidence for subsidence in the 1989 Arctic winter stratosphere from airborne infrared composition measurements

    NASA Technical Reports Server (NTRS)

    Toon, G. C.; Farmer, C. B.; Schaper, P. W.; Lowes, L. L.; Norton, R. H.; Schoeberl, M. R.; Lait, L. R.; Newman, P. A.

    1992-01-01

    Simultaneous measurements of the stratospheric burdens of CO2, HCN, N2O, CH4, OCS, CF2Cl2, CFCl3, CHF2Cl and HF were made by the Jet propulsion Laboratory MkIV interferometer on board the NASA DC-8 aircraft during January and early February 1989 as part of the Airborne Arctic Stratosphere Experiment. Data were acquired on 11 flights at altitudes of up to 12 km over a geographic region covering the NE Atlantic Ocean, Iceland and Greenland. The results obtained show large variations in the burdens of these tracers due to the effects of transport. The tropospheric source gas burdens were reduced inside the polar vortex, suggesting that the air had subsided with respect to the surrounding midlatitude air. Increased HF burdens inside the vortex support this interpretation. The results obtained from the different tracers are highly consistent with each other and indicate that in the 15- to 20-km altitude range inside the vortex, surfaces of constant volume mixing ratio were located some 5-6 km lower in absolute altitude than outside the vortex. The results also indicate that the magnitude of this subsidence increases with altitude. These conclusions are consistent with other measurements.

  2. Analysis of satellite and airborne wind measurements during the SEMAPHORE experiment

    SciTech Connect

    Tournadre, J.; Hauser, D.

    1994-12-31

    During the SEMAPHORE experiment Intensive Observation Period (IOP), held in October and November 1993 in the Azores-Madeira region, two airplanes, instrumented for atmospheric research, and two oceanographic research vessels have conducted in situ measurements in a 500km x 500km domain. Within the framework of SEMAPHORE, the SOFIA program is dedicated to the study of the air-sea fluxes and interactions from local scale up to mesoscale. The analysis of the structure of the wind and wave fields and their relations to the surface fluxes (especially near oceanic fronts) and the validation of the satellite data are two of the main goals of the SOFIA program. During the IOP, the experiment domain was regularly overflown by the ERS-1 and Topex-Poseidon (TP) satellites. This study presents a preliminary analysis of the ERS-1 and TP altimeter wind and wave measurement and ERS-1 scatterometer wind fields. The data from the airborne RESSAC (a radar ocean wave spectrometer) are also presented.

  3. Surface and airborne measurements of organosulfur and methanesulfonate over the western United States and coastal areas

    NASA Astrophysics Data System (ADS)

    Sorooshian, Armin; Crosbie, Ewan; Maudlin, Lindsay C.; Youn, Jong-Sang; Wang, Zhen; Shingler, Taylor; Ortega, Amber M.; Hersey, Scott; Woods, Roy K.

    2015-08-01

    This study reports on ambient measurements of organosulfur (OS) and methanesulfonate (MSA) over the western United States and coastal areas. Particulate OS levels are highest in summertime and generally increase as a function of sulfate (a precursor) and sodium (a marine tracer) with peak levels at coastal sites. The ratio of OS to total sulfur is also highest at coastal sites, with increasing values as a function of normalized difference vegetation index and the ratio of organic carbon to elemental carbon. Correlative analysis points to significant relationships between OS and biogenic emissions from marine and continental sources, factors that coincide with secondary production, and vanadium due to a suspected catalytic role. A major OS species, methanesulfonate (MSA), was examined with intensive field measurements, and the resulting data support the case for vanadium's catalytic influence. Mass size distributions reveal a dominant MSA peak between aerodynamic diameters of 0.32-0.56 µm at a desert and coastal site with nearly all MSA mass (≥84%) in submicrometer sizes; MSA:non-sea-salt sulfate ratios vary widely as a function of particle size and proximity to the ocean. Airborne data indicate that relative to the marine boundary layer, particulate MSA levels are enhanced in urban and agricultural areas and also the free troposphere when impacted by biomass burning. Some combination of fires and marine-derived emissions leads to higher MSA levels than either source alone. Finally, MSA differences in cloud water and out-of-cloud aerosol are discussed.

  4. 47 CFR 15.33 - Frequency range of radiated measurements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... § 15.33 Frequency range of radiated measurements. (a) For an intentional radiator, the spectrum shall... kHz, up to at least the frequency shown in this paragraph: (1) If the intentional radiator operates... lower. (2) If the intentional radiator operates at or above 10 GHz and below 30 GHz: to the...

  5. 47 CFR 15.33 - Frequency range of radiated measurements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... § 15.33 Frequency range of radiated measurements. (a) For an intentional radiator, the spectrum shall... kHz, up to at least the frequency shown in this paragraph: (1) If the intentional radiator operates... lower. (2) If the intentional radiator operates at or above 10 GHz and below 30 GHz: to the...

  6. 47 CFR 15.33 - Frequency range of radiated measurements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... § 15.33 Frequency range of radiated measurements. (a) For an intentional radiator, the spectrum shall... kHz, up to at least the frequency shown in this paragraph: (1) If the intentional radiator operates... lower. (2) If the intentional radiator operates at or above 10 GHz and below 30 GHz: to the...

  7. 47 CFR 15.33 - Frequency range of radiated measurements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... § 15.33 Frequency range of radiated measurements. (a) For an intentional radiator, the spectrum shall... kHz, up to at least the frequency shown in this paragraph: (1) If the intentional radiator operates... lower. (2) If the intentional radiator operates at or above 10 GHz and below 30 GHz: to the...

  8. Estimating shortwave solar radiation using net radiation and meteorological measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shortwave radiation has a wide variety of uses in land-atmosphere interactions research. Actual evapotranspiration estimation that involves stomatal conductance models like Jarvis and Ball-Berry require shortwave radiation to estimate photon flux density. However, in most weather stations, shortwave...

  9. SUMER: Solar Ultraviolet Measurements of Emitted Radiation

    NASA Technical Reports Server (NTRS)

    Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.; Grewing, M.; Huber, M. C. E.; Jordan, S. D.; Kuehne, M.; Lemaire, P.; Marsch, E.

    1992-01-01

    The experiment Solar Ultraviolet Measurements of Emitted Radiation (SUMER) is designed for the investigations of plasma flow characteristics, turbulence and wave motions, plasma densities and temperatures, structures and events associated with solar magnetic activity in the chromosphere, the transition zone and the corona. Specifically, SUMER will measure profiles and intensities of Extreme Ultraviolet (EUV) lines emitted in the solar atmosphere ranging from the upper chromosphere to the lower corona; determine line broadenings, spectral positions and Doppler shifts with high accuracy, provide stigmatic images of selected areas of the Sun in the EUV with high spatial, temporal and spectral resolution and obtain full images of the Sun and the inner corona in selectable EUV lines, corresponding to a temperature from 10,000 to more than 1,800,000 K.

  10. Technical Note: Characterisation of a DUALER instrument for the airborne measurement of peroxy radicals during AMMA 2006

    NASA Astrophysics Data System (ADS)

    Kartal, D.; Andrés-Hernández, M. D.; Reichert, L.; Schlager, H.; Burrows, J. P.

    2010-03-01

    A DUALER (dual-channel airborne peroxy radical chemical amplifier) instrument has been developed and optimised for the airborne measurement of the total sum of peroxy radicals during the AMMA (African Monsoon Multidisciplinary Analyses) measurement campaign which took place in Burkina Faso in August 2006. The innovative feature of the instrument is that both reactors are sampling simultaneously from a common pre-reactor nozzle while the whole system is kept at a constant pressure to ensure more signal stability and accuracy. Laboratory experiments were conducted to characterise the stability of the NO2 detector signal and the chain length with the pressure. The results show that airborne measurements using chemical amplification require constant pressure at the luminol detector. Wall losses of main peroxy radicals HO2 and CH3O2 were investigated. The chain length was experimentally determined for different ambient mixtures and compared with simulations performed by a chemical box model. The DUALER instrument was successfully mounted within the German DLR-Falcon. The analysis of AMMA data utilises a validation procedure based on the O3 mixing ratios simultaneously measured onboard. The validation and analysis procedure is illustrated by means of the data measured during the AMMA campaign. The detection limit and the accuracy of the ambient measurements are also discussed.

  11. Atmospheric CO2 measurements with a 2 μm airborne laser absorption spectrometer employing coherent detection.

    PubMed

    Spiers, Gary D; Menzies, Robert T; Jacob, Joseph; Christensen, Lance E; Phillips, Mark W; Choi, Yonghoon; Browell, Edward V

    2011-05-10

    We report airborne measurements of CO(2) column abundance conducted during two 2009 campaigns using a 2.05 μm laser absorption spectrometer. The two flight campaigns took place in the California Mojave desert and in Oklahoma. The integrated path differential absorption (IPDA) method is used for the CO(2) column mixing ratio retrievals. This instrument and the data analysis methodology provide insight into the capabilities of the IPDA method for both airborne measurements and future global-scale CO(2) measurements from low Earth orbit pertinent to the NASA Active Sensing of CO(2) Emissions over Nights, Days, and Seasons mission. The use of a favorable absorption line in the CO(2) 2 μm band allows the on-line frequency to be displaced two (surface pressure) half-widths from line center, providing high sensitivity to the lower tropospheric CO(2). The measurement repeatability and measurement precision are in good agreement with predicted estimates. We also report comparisons with airborne in situ measurements conducted during the Oklahoma campaign.

  12. Measurement and assessment of radiation dose of astronauts in space

    NASA Astrophysics Data System (ADS)

    Zhang, Binquan; Sun, Yue-qiang; Yang, Chuibai; Zhang, Shenyi; Liang, Jinbao

    Astronauts in flight are exposed by the space radiation, which is mainly composed of proton, electron, heavy ion, and neutron. To assess the radiation risk, measurement and assessment of radiation dose of astronauts is indispensable. Especially, measurement for heavy ion radiation is most important as it contributes the major dose. Until now, most of the measurements and assessments of radiation dose of astronauts are based on the LET (Linear Energy Transfer) spectrum of space radiation. However, according to the ICRP Publication 123, energy and charge number of heavy ions should be measured in order to assess space radiation exposure to astronauts. In addition, from the publication, quality factors for each organs or tissues of astronauts are different and they should be calculated or measured independently. Here, a method to measure the energy and charge number of heavy ion and a voxel phantom based on the anatomy of Chinese adult male are presented for radiation dose assessment of astronauts.

  13. Validating SWE reconstruction using Airborne Snow Observatory measurements in the Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Bair, N.; Rittger, K.; Davis, R. E.; Dozier, J.

    2015-12-01

    The Airborne Snow Observatory (ASO) program offers high resolution estimates of snow water equivalent (SWE) in several small basins across California during the melt season. Primarily, water managers use this information to model snowmelt runoff into reservoirs. Another, and potentially more impactful, use of ASO SWE measurements is in validating and improving satellite-based SWE estimates which can be used in austere regions with no ground-based snow or water measurements, such as Afghanistan's Hindu Kush. Using the entire ASO dataset to date (2013-2015) which is mostly from the Upper Tuolumne basin, but also includes measurements from 2015 in the Kings, Rush Creek, Merced, and Mammoth Lakes basins, we compare ASO measurements to those from a SWE reconstruction method. Briefly, SWE reconstruction involves downscaling energy balance forcings to compute potential melt energy, then using satellite-derived estimates of fractional snow covered area (fSCA) to estimate snow melt from potential melt. The snowpack can then be built in reverse, given a remotely-sensed date of snow disappearance (fSCA=0). Our model has improvements over previous iterations in that it: uses the full energy balance (compared to a modified degree-day) approach, models bulk and surface snow temperatures, accounts for ephemeral snow, and uses a remotely-sensed snow albedo adjusted for impurities. To check that ASO provides accurate snow measurements, we compare fSCA derived from ASO snow depth at 3 m resolution with fSCA from a spectral unmixing algorithm for LandSAT at 30 m, and from binary SCA estimates from Geoeye at 0.5 m from supervised classification. To conclude, we document how our reconstruction model has evolved over the years and provide specific examples where improvements have been made using ASO and other verification sources.

  14. Filter measurements of chemical composition during the airborne Antarctic ozone experiment

    NASA Technical Reports Server (NTRS)

    Grandrud, B. W.; Sperry, P. D.; Sanford, L.

    1988-01-01

    During the Airborne Antarctic Ozone Experiment campaign, a filter sampler was flown to measure the bulk composition of aerosol and gas phases. The background sulfate aerosol was measured in regions inside and outside of the chemically perturbed region (CPR) of the polar vortex. The mass ratio of sulfate outside to inside was 2.8. This is indicative of a cleansing mechanism effecting the CPR or of a different air mass inside versus outside. The absolute value of the sulfate mixing ratio shows that the background aerosol has not been influenced by recent volcanic eruptions. The sulfate measured on the ferry flight returning to NASA Ames shows a decrease towards the equator with increasing concentrations in the northern hemisphere. Nitrate in the aerosol phase was observed on two flights. The largest amount of nitrate measured in the aerosol was 44 percent of the total amount of nitrate observed. Other samples on the same flights show no nitrate in the aerosol phase. The presence of nitrate in the aerosol is correlated with the coldest temperatures observed on a given flight. Total nitrate (aerosol plus acidic vapor nitrate) concentrations were observed to increase at flight altitude with increasing latitude north and south of the equator. Total nitrate was lower inside the CPR than outside. Chloride and flouride were not detected in the aerosol phase. From the concentrations of acidic chloride vapor, the ratio of acidic vapor Cl to acidic vapor F and a summing of the individual chloride containing species to yield a total chloride concentration, there is a suggestion that some of the air sampled was dechlorinated. Acidic vapor phase fluoride was observed to increase at flight altitude with increasing latitude both north and south of the equator. The acidic vapor phase fluoride was the only compound measured with the filter technique that exhibited larger concentrations inside the CPR than outside.

  15. High-accuracy continuous airborne measurements of greenhouse gases (CO2 and CH4) during BARCA

    NASA Astrophysics Data System (ADS)

    Chen, H.; Winderlich, J.; Gerbig, C.; Hoefer, A.; Rella, C. W.; Crosson, E. R.; van Pelt, A. D.; Steinbach, J.; Kolle, O.; Beck, V.; Daube, B. C.; Gottlieb, E. W.; Chow, V. Y.; Santoni, G. W.; Wofsy, S. C.

    2009-12-01

    High-accuracy continuous measurements of greenhouse gases (CO2 and CH4) during the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) phase B campaign in Brazil in May 2009 were accomplished using a newly available analyzer based on the cavity ring-down spectroscopy (CRDS) technique. This analyzer was flown without a drying system or any in-flight calibration gases. Water vapor corrections associated with dilution and pressure-broadening effects for CO2 and CH4 were derived from laboratory experiments employing measurements of water vapor by the CRDS analyzer. Before the campaign, the stability of the analyzer was assessed by laboratory tests under simulated flight conditions. During the campaign, a comparison of CO2 measurements between the CRDS analyzer and a nondispersive infrared (NDIR) analyzer on board the same aircraft showed a mean difference of 0.22±0.09 ppm for all flights over the Amazon rain forest. At the end of the campaign, CO2 concentrations of the synthetic calibration gases used by the NDIR analyzer were determined by the CRDS analyzer. After correcting for the isotope and the pressure-broadening effects that resulted from changes of the composition of synthetic vs. ambient air, and applying those concentrations as calibrated values of the calibration gases to reprocess the CO2 measurements made by the NDIR, the mean difference between the CRDS and the NDIR during BARCA was reduced to 0.05±0.09 ppm, with the mean standard deviation of 0.23±0.05 ppm. The results clearly show that the CRDS is sufficiently stable to be used in flight without drying the air or calibrating in flight and the water corrections are fully adequate for high-accuracy continuous airborne measurements of CO2 and CH4.

  16. Ground and Airborne Aerosol Composition Measurements of California Coastal Chaparral Smoke Emissions

    NASA Astrophysics Data System (ADS)

    Craven, J. S.; Sorooshian, A.; Hersey, S. P.; Metcalf, A. R.; Schilling-Fahnestock, K.; Newman, S.; Akagi, S. K.; Taylor, J.; McMeeking, G.; Coe, H.; Tang, P.; Cocker, D. R., III; Yokelson, R. J.; Flagan, R. C.; Seinfeld, J.

    2014-12-01

    Wildfire smoke has large local to global pollution impacts. We present aerosol composition data from two fires in southern California. We measured organic aerosol (OA) of nascent and aged (4 h) smoke from the Williams Fire during the 2009 airborne San Luis Obispo Biomass Burning Campaign (SLOBB). The net ΔOA/ΔCO2 decreased by ~20%; however, positive matrix factorization (PMF) analysis of the organic mass spectra supports two factors that enable the OA emissions to be separated into fresh and oxidized OA. The Δfresh BBOA/ΔCO2 had a steeper decline than the ΔOA/ΔCO2 consistent with outgassing of semi-voltile organic compounds (SVOCs) due to dilution, whereas the Δoxidized BBOA/ΔCO2 increased from its initial value, consist with formation of secondary organic aerosol (SOA). We compare these fresh and oxidized mass spectral signatures, along with chaparral smoke samples measured in the Missoula Fire Lab, to ground-based aerosol measurements made during the Station Fire that occurred one month earlier than the Williams Fire during the Pasadena Aerosol Characterization Observatory Campaign (PACO). Night and daytime aerosol smoke emissions were sampled for one week during the Station Fire. Daytime organic aerosol smoke emissions exhibited larger variability both in mass concentration and composition than nighttime smoke emissions. Both levoglucosan and potassium, known biomass burning tracers, were measured and had distinct time series, supporting diversity in the flaming vs. smoldering initial burning conditions. Similar to the Williams Fire, PMF of the Station Fire mass spectra also reveal two biomass burning factors, one that is less oxidized and correlates strongly with levoglucosan measurements and one that is heavily oxidized and correlates in time with the potassium signal. These two campaigns have allowed us to probe fresh and oxidized smoke in both night and daytime conditions, and PMF results have revealed that at least two emission factors are useful to

  17. Comparison of Continuous Wave CO2 Doppler Lidar Calibration Using Earth Surface Targets in Laboratory and Airborne Measurements

    NASA Technical Reports Server (NTRS)

    Jarzembski, Maurice A.; Srivastava, Vandana

    1999-01-01

    Routine backscatter, beta, measurements by an airborne or space-based lidar from designated earth surfaces with known and fairly uniform beta properties can potentially offer lidar calibration opportunities. This can in turn be used to obtain accurate atmospheric aerosol and cloud beta measurements on large spatial scales. This is important because achieving a precise calibration factor for large pulsed lidars then need not rest solely on using a standard hard target procedure. Furthermore, calibration from designated earth surfaces would provide an inflight performance evaluation of the lidar. Hence, with active remote sensing using lasers with high resolution data, calibration of a space-based lidar using earth's surfaces will be extremely useful. The calibration methodology using the earth's surface initially requires measuring beta of various earth surfaces simulated in the laboratory using a focused continuous wave (CW) CO2 Doppler lidar and then use these beta measurements as standards for the earth surface signal from airborne or space-based lidars. Since beta from the earth's surface may be retrieved at different angles of incidence, beta would also need to be measured at various angles of incidences of the different surfaces. In general, Earth-surface reflectance measurements have been made in the infrared, but the use of lidars to characterize them and in turn use of the Earth's surface to calibrate lidars has not been made. The feasibility of this calibration methodology is demonstrated through a comparison of these laboratory measurements with actual earth surface beta retrieved from the same lidar during the NASA/Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) mission on NASA's DC8 aircraft from 13 - 26 September, 1995. For the selected earth surface from the airborne lidar data, an average beta for the surface was established and the statistics of lidar efficiency was determined. This was compared with the actual lidar efficiency

  18. Testing of a Two-Micron Double-Pulse IPDA Lidar Instrument for Airborne Atmospheric Carbon Dioxide Measurement

    NASA Astrophysics Data System (ADS)

    Yu, J.; Petros, M.; Refaat, T. F.; Remus, R.; Singh, U. N.

    2015-12-01

    Utilizing a tunable two-micron double-pulse laser transmitter, an airborne IPDA lidar system has been developed at NASA Langley Research Center for atmospheric carbon dioxide column measurements. The instrument comprises a receiver with 0.4 m telescope and InGaAs pin detectors coupled to 12-bit, 200 MS/s waveform digitizers. For on-site ground testing, the 2-μm CO2 IPDA lidar was installed inside a trailer located where meteorological data and CO2 mixing ratio profiles were obtained from CAPABLE and LiCoR in-suite sampling, respectively. IPDA horizontal ground testing with 860 m target distance indicated CO2 sensitivity of 2.24 ppm with -0.43 ppm offset, while operating at 3 GHz on-line position from the R30 line center. Then, the IPDA lidar was integrated inside the NASA B-200 aircraft, with supporting instrumentation, for airborne testing and validation. Supporting instruments included in-situ LiCoR sensor, GPS and video recorder for target identification. Besides, aircraft built-in sensors provided altitude, pressure, temperature and relative humidity sampling during flights. The 2-mm CO2 IPDA lidar airborne testing was conducted through ten daytime flights (27 hours flight time). Airborne testing included different operating and environmental conditions for flight altitude up to 7 km, different ground target conditions such as vegetation, soil, ocean, snow and sand and different cloud conditions. Some flights targeted power plant incinerators for investigating IPDA sensitivity to CO2 plums. Relying on independent CO2 in-situ sampling, conducted through NOAA, airborne IPDA CO2 sensitivity of 4.15 ppm with 1.14 ppm offset were observed at 6 km altitude and 4 GHz on-line offset frequency. This validates the 2-μm double-pulse IPDA lidar for atmospheric CO2 measurement.

  19. Measurement of Airborne Fission Products in Chapel Hill, NC, USA from the Kukushima Dai-ichi Reactor Accident

    SciTech Connect

    MacMullin, S.; Giovanetti, G. K.; Green, M. P.; Henning, R.; Holmes, R.; Vorren, K.

    2012-01-01

    We present measurement results of airborne fission products in Chapel Hill, NC, USA, from 62 d following the March 11, 2011, accident at the Fukushima Dai-ichi nuclear power plant. Airborne particle samples were collected daily in air filters and radio-assayed with two high-purity germanium (HPGe) detectors. The fission products 131I and 137Cs were measured with maximum activity concentrations of 4.2 0.6 mBq/m3 and 0.42 0.07 mBq/m3 respectively. Additional activity from 131,132I, 134,136,137Cs and 132Te were measured in the same air filters using a low-background HPGe detector at the Kimballton Underground Research Facility (KURF).

  20. Boundary Layer CO2 mixing ratio measurements by an airborne pulsed IPDA lidar

    NASA Astrophysics Data System (ADS)

    Ramanathan, A. K.; Mao, J.; Abshire, J. B.; Allan, G. R.

    2014-12-01

    Since the primary signature of CO2 fluxes at the surface occurs in the planetary boundary layer (PBL), remote sensing measurements of CO2 that can resolve the CO2 absorption in the PBL separate from the total column are more sensitive to fluxes than those that can only measure a total column. The NASA Goddard CO2 sounder is a pulsed, range-resolved lidar that samples multiple (presently 30) wavelengths across the 1572.335 nm CO2 absorption line. The range resolution and line shape measurement enable CO2 mixing ratio measurements to be made in two or more altitude layers including the PBL via lidar cloud-slicing and multi-layer retrievals techniques. The pulsed lidar approach allows range-resolved backscatter of scattering from ground and cloud tops. Post flight data analysis can be used split the vertical CO2 column into layers (lidar cloud-slicing) and solve for the CO2 mixing ratio in each layer. We have demonstrated lidar cloud slicing with lidar measurements from a flight over Iowa, USA in August 2011 during the corn-growing season, remotely measuring a ≈15 ppm drawdown in the PBL CO2. We will present results using an improved lidar cloud slicing retrieval algorithm as well as preliminary measurements from the upcoming ASCENDS 2014 flight campaign. The CO2 absorption line is also more pressure broadened at lower altitudes. Analyzing the line shape also allows solving for some vertical resolution in the CO2 distribution. By allowing the retrieval process to independently vary the column concentrations in two or more altitude layers, one can perform a best-fit retrieval to obtain the CO2 mixing ratios in each of the layers. Analysis of airborne lidar measurements (in 2011) over Iowa, USA and Four Corners, New Mexico, USA show that for altitudes above 8 km, the CO2 sounder can detect and measure enhanced or diminished CO2 mixing ratios in the PBL even in the absence of clouds. We will present these results as well as preliminary measurements from the upcoming

  1. Airborne MAX-DOAS Measurements Over California: Testing the NASA OMI Tropospheric NO2 Product

    NASA Technical Reports Server (NTRS)

    Oetjen, Hilke; Baidar, Sunil; Krotkov, Nickolay A.; Lamsal, Lok N.; Lechner, Michael; Volkamer, Rainer

    2013-01-01

    Airborne Multi-AXis Differential Optical Absorption Spectroscopy (AMAX-DOAS) measurements of NO2 tropospheric vertical columns were performed over California for two months in summer 2010. The observations are compared to the NASA Ozone Monitoring Instrument (OMI) tropospheric vertical columns (data product v2.1) in two ways: (1) Median data were compared for the whole time period for selected boxes, and the agreement was found to be fair (R = 0.97, slope = 1.4 +/- 0.1, N= 10). (2) A comparison was performed on the mean of coincident AMAX-DOAS measurements within the area of the corresponding OMI pixels with the tropospheric NASA OMI NO2 assigned to that pixel. The effects of different data filters were assessed. Excellent agreement and a strong correlation (R = 0.85, slope = 1.05 +/- 0.09, N= 56) was found for (2) when the data were filtered to eliminate large pixels near the edge of the OMI orbit, the cloud radiance fraction was<50%, the OMI overpass occurred within 2 h of the AMAX-DOAS measurements, the flight altitude was>2 km, and a representative sample of the footprint was taken by the AMAX-DOAS instrument. The AMAX-DOAS and OMI data sets both show a reduction of NO2 tropospheric columns on weekends by 38 +/- 24% and 33 +/- 11%, respectively. The assumptions in the tropospheric satellite air mass factor simulations were tested using independent measurements of surface albedo, aerosol extinction, and NO2 profiles for Los Angeles for July 2010 indicating an uncertainty of 12%.

  2. Nitrous oxide (N2O) emissions from California based on 2010 CalNex airborne measurements

    NASA Astrophysics Data System (ADS)

    Xiang, Bin; Miller, Scot M.; Kort, Eric A.; Santoni, Gregory W.; Daube, Bruce C.; Commane, Roisin; Angevine, Wayne M.; Ryerson, Tom B.; Trainer, Michael K.; Andrews, Arlyn E.; Nehrkorn, Thomas; Tian, Hanqin; Wofsy, Steven C.

    2013-04-01

    Nitrous oxide (N2O) is an important gas for climate and for stratospheric chemistry, with a lifetime exceeding 100 years. Global concentrations have increased steadily since the 18th century, apparently due to human-associated emissions, principally from the application of nitrogen fertilizers. However, quantitative studies of agricultural emissions at large spatial scales are lacking, inhibited by the difficulty of measuring small enhancements in atmospheric concentration. Here we derive regional emission rates for N2O in the agricultural heartland of California based on analysis of in-situ airborne atmospheric observations collected using a new quantum cascade laser spectrometer. The data were obtained on board the NOAA WP-3 research aircraft during the CalNex (California Research at the Nexus of Air Quality and Climate Change) program in late spring 2010. We coupled the WRF (weather research and forecasting) model, a meso-scale meteorology model, with the STILT (stochastic time-inverted Lagrangian transport) model, a Lagrangian particle dispersion model, to link our in-situ airborne observations to surface emissions. We then used a variety of statistical methods to identify source areas and to optimize emission rates. Our results are consistent with the view that fertilizer application is the largest source of N2O in the Central Valley. The spatial distribution of surface emissions, based on California land use and activity maps, was very different than indicated in the leading emission inventory (EDGAR 4.0). Our estimated total emission flux of N2O for California in May and June was 3 - 4 times larger than the annual mean given for the state by EDGAR and other inventories, indicating a strong seasonal variation. We estimated the statewide total annual emissions of N2O to be 0.042 ± 0.011 Tg N/year, roughly equivalent to inventory values if we account for seasonal variations using observations obtained in the midwestern United States. This state total N2O

  3. Airborne measurements of HC(O)OH in the European Arctic: A winter - summer comparison

    NASA Astrophysics Data System (ADS)

    Jones, Benjamin T.; Muller, Jennifer B. A.; O'Shea, Sebastian J.; Bacak, Asan; Le Breton, Michael; Bannan, Thomas J.; Leather, Kimberley E.; Booth, A. Murray; Illingworth, Sam; Bower, Keith; Gallagher, Martin W.; Allen, Grant; Shallcross, Dudley E.; Bauguitte, Stephane J.-B.; Pyle, John A.; Percival, Carl J.

    2014-12-01

    This study represents the first airborne, in-situ measurements of HC(O)OH in the European Arctic, across the winter and summer seasons. HC(O)OH concentrations are under predicted at present, particularly in the mid to high northern latitudes. Data presented here probe unconfirmed sources of HC(O)OH in the Arctic, and would suggest an ocean source of HC(O)OH is more significant than proposed land sources in both winter and summer environments. A maximum concentration of 420 ppt was recorded over the ocean during the July 2012 campaign. This was more than 1.7 times greater than the maximum land concentration reported. Calculated estimates on HC(O)OH production would suggest diiodomethane photolysis could represent a significant source of HC(O)OH in marine environments in the European Arctic. Enhanced HC(O)OH concentrations observed at altitudes greater than 2 km particularly during the March campaign highlight the significance of long range transport on the European Arctic budget. In addition, two HC(O)OH vertical profiles between the altitudes 0.3-6.6 km are presented to provide a more representative vertical profile for this latitude which may be used to improve forthcoming regional and global modelling of the HC(O)OH budget.

  4. Airborne water vapor DIAL system and measurements of water and aerosol profiles

    NASA Technical Reports Server (NTRS)

    Higdon, Noah S.; Browell, Edward V.

    1991-01-01

    The Lidar Applications Group at NASA Langley Research Center has developed a differential absorption lidar (DIAL) system for the remote measurement of atmospheric water vapor (H2O) and aerosols from an aircraft. The airborne H2O DIAL system is designed for extended flights to perform mesoscale investigations of H2O and aerosol distributions. This DIAL system utilizes a Nd:YAG-laser-pumped dye laser as the off-line transmitter and a narrowband, tunable Alexandrite laser as the on-line transmitter. The dye laser has an oscillator/amplifier configuration which incorporates a grating and prism in the oscillator cavity to narrow the output linewidth to approximately 15 pm. This linewidth can be maintained over the wavelength range of 725 to 730 nm, and it is sufficiently narrow to satisfy the off-line spectral requirements. In the Alexandrite laser, three intracavity tuning elements combine to produce an output linewidth of 1.1 pm. These spectral devices include a five-plate birefringent tuner, a 1-mm thick solid etalon and a 1-cm air-spaced etalon. A wavelength stability of +/- 0.35 pm is achieved by active feedback control of the two Fabry-Perot etalons using a frequency stabilized He-Ne laser as a wavelength reference. The three tuning elements can be synchronously scanned over a 150 pm range with microprocessor-based scanning electronics. Other aspects of the DIAL system are discussed.

  5. Measuring Geophysical Parameters of the Greenland Ice Sheet using Airborne Radar Altimetry

    NASA Technical Reports Server (NTRS)

    Ferraro, Ellen J.; Swift. Calvin T.

    1995-01-01

    This paper presents radar-altimeter scattering models for each of the diagenetic zones of the Greenland ice sheet. AAFE radar- altimeter waveforms obtained during the 1991 and 1993 NASA multi-sensor airborne altimetry experiments over Greenland reveal that the Ku-band return pulse changes significantly with the different diagenetic zones. These changes are due to varying amounts of surface and volume scattering in the return waveform. In the ablation and soaked zones, where surface scattering dominates the AAFE return, geophysical parameters such as rms surface height and rms surface slope are obtained by fitting the waveforms to a surface-scattering model. Waveforms from the percolation zone show that the sub-surface ice features have a much more significant effect on the return pulse than the surrounding snowpack. Model percolation waveforms, created using a combined surface- and volume-scattering model and an ice-feature distribution obtained during the 1993 field season, agree well with actual AAFE waveforms taken in the same time period. Using a combined surface- and volume-scattering model for the dry-snow-zone return waveforms, the rms surface height and slope and the attenuation coefficient of the snowpack are obtained. These scattering models not only allow geophysical parameters of the ice sheet to be measured but also help in the understanding of satellite radar-altimeter data.

  6. Composition measurements of the 1989 Arctic winter stratosphere by airborne infrared solar absorption spectroscopy

    NASA Technical Reports Server (NTRS)

    Toon, G. C.; Farmer, C. B.; Schaper, P. W.; Lowes, L. L.; Norton, R. H.

    1992-01-01

    The paper reports simultaneous measurements of the stratospheric burdens of H2O, HDO, OCS, CO2, O3, N2O, CO, CH4, CF2Cl2, CFCl3, CHF2Cl, C2H6, HCN, NO, NO2, HNO3, ClNO3, HOCl, HCl, and HF made by the JPL MkIV interferometer on board the NASA DC-8 aircraft during January and early February 1989 as part of the Airborne Arctic Stratosphere Experiment. Data were obtained on 11 flights at altitudes of up to 12 km over a geographic region covering the NE Atlantic Ocean, Iceland, and Greenland. Analyses of the chemically active gases reveal highly perturbed conditions within the vortex. The ClNO3 abundance was chemically enhanced near the edge of the vortex but was then depleted inside. NO2 was severely depleted inside the vortex. In contrast to Antarctica, H2O and HNO3 were both more abundant inside the vortex than outside. It is suggested that although the Arctic vortex did not get cold enough to produce any dehydration, or as vertically extensive denitrification as occurred in Antarctica, nevertheless, enough heterogeneous chemistry occurred to convert over 90 percent of the inorganic chlorine to active forms in the 14- to 27-km altitude range by early February 1989.

  7. Ship emissions of SO2 and NO2: DOAS measurements from airborne platforms

    NASA Astrophysics Data System (ADS)

    Berg, N.; Mellqvist, J.; Jalkanen, J.-P.; Balzani, J.

    2012-05-01

    A unique methodology to measure gas fluxes of SO2 and NO2 from ships using optical remote sensing is described and demonstrated in a feasibility study. The measurement system is based on Differential Optical Absorption Spectroscopy using reflected skylight from the water surface as light source. A grating spectrometer records spectra around 311 nm and 440 nm, respectively, with the telescope pointed downward at a 30° angle from the horizon. The mass column values of SO2 and NO2 are retrieved from each spectrum and integrated across the plume. A simple geometric approximation is used to calculate the optical path. To obtain the total emission in kg h-1 the resulting total mass across the plume is multiplied with the apparent wind, i.e. a dilution factor corresponding to the vector between the wind and the ship speed. The system was tested in two feasibility studies in the Baltic Sea and Kattegat, from a CASA-212 airplane in 2008 and in the North Sea outside Rotterdam from a Dauphin helicopter in an EU campaign in 2009. In the Baltic Sea the average SO2 emission out of 22 ships was (54 ± 13) kg h-1, and the average NO2 emission was (33 ± 8) kg h-1, out of 13 ships. In the North Sea the average SO2 emission out of 21 ships was (42 ± 11) kg h-1, NO2 was not measured here. The detection limit of the system made it possible to detect SO2 in the ship plumes in 60% of the measurements when the described method was used. A comparison exercise was carried out by conducting airborne optical measurements on a passenger ferry in parallel with onboard measurements. The comparison shows agreement of (-30 ± 14)% and (-41 ± 11)%, respectively, for two days, with equal measurement precision of about 20%. This gives an idea of the measurement uncertainty caused by errors in the simple geometric approximation for the optical light path neglecting scattering of the light in ocean waves and direct and multiple scattering in the exhaust plume under various conditions. A tentative

  8. Ground truth data for test sites (SL-3). [solar radiation and thermal radiation brightness temperature measurements

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Field measurements performed simultaneously with Skylab overpasses in order to provide comparative calibration and performance evaluation measurements for the EREP sensors are presented. The solar radiation region from 400 to 1300 nanometers and the thermal radiation region from 8 to 14 micrometer region were investigated. The measurements of direct solar radiation were analyzed for atmospheric optical depth; the total and reflected solar radiation were analyzed for target reflectivity. These analyses were used in conjunction with a radiative transfer computer program in order to calculate the amount and spectral distribution of solar radiation at the apertures of the EREP sensors. The instrumentation and techniques employed, calibrations and analyses performed, and results obtained are discussed.

  9. Measurement of solar radiation at the Earth's surface

    NASA Technical Reports Server (NTRS)

    Bartman, F. L.

    1982-01-01

    The characteristics of solar energy arriving at the surface of the Earth are defined and the history of solar measurements in the United States presented. Radiation and meteorological measurements being made at solar energy meteorological research and training sites and calibration procedures used there are outlined. Data illustrating the annual variation in daily solar radiation at Ann Arbor, Michigan and the diurnal variation in radiation at Albuquerque, New Mexico are presented. Direct normal solar radiation received at Albuquerque is contrasted with that received at Maynard, Massachusetts. Average measured global radiation for a period of one year for four locations under clear skies, 50% cloud cover, and 100% cloud cover is given and compared with the solar radiation at the top of the atmosphere. The May distribution of mean daily direct solar radiation and mean daily global solar radiation over the United States is presented. The effects of turbidity on the direct and circumsolar radiation are shown.

  10. Airborne cloud condensation nuclei measurements during the 2006 Texas Air Quality Study

    NASA Astrophysics Data System (ADS)

    Asa-Awuku, Akua; Moore, Richard H.; Nenes, Athanasios; Bahreini, Roya; Holloway, John S.; Brock, Charles A.; Middlebrook, Ann M.; Ryerson, Thomas B.; Jimenez, Jose L.; Decarlo, Peter F.; Hecobian, Arsineh; Weber, Rodney J.; Stickel, Robert; Tanner, Dave J.; Huey, Lewis G.

    2011-06-01

    Airborne measurements of aerosol and cloud condensation nuclei (CCN) were conducted aboard the National Oceanic and Atmospheric Administration WP-3D platform during the 2006 Texas Air Quality Study/Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS/GoMACCS). The measurements were conducted in regions influenced by industrial and urban sources. Observations show significant local variability of CCN activity (CCN/CN from 0.1 to 0.5 at s = 0.43%), while variability is less significant across regional scales (˜100 km × 100 km; CCN/CN is ˜0.1 at s = 0.43%). CCN activity can increase with increasing plume age and oxygenated organic fraction. CCN measurements are compared to predictions for a number of mixing state and composition assumptions. Mixing state assumptions that assumed internally mixed aerosol predict CCN concentrations well. Assuming organics are as hygroscopic as ammonium sulfate consistently overpredicted CCN concentrations. On average, the water-soluble organic carbon (WSOC) fraction is 60 ± 14% of the organic aerosol. We show that CCN closure can be significantly improved by incorporating knowledge of the WSOC fraction with a prescribed organic hygroscopicity parameter (κ = 0.16 or effective κ ˜ 0.3). This implies that the hygroscopicity of organic mass is primarily a function of the WSOC fraction. The overall aerosol hygroscopicity parameter varies between 0.08 and 0.88. Furthermore, droplet activation kinetics are variable and 60% of particles are smaller than the size characteristic of rapid droplet growth.

  11. On-board Polarimetric Calibration of Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) Measurements

    NASA Astrophysics Data System (ADS)

    van Harten, G.; Diner, D. J.; Bull, M. A.; Tkatcheva, I. N.; Jovanovic, V. M.; Seidel, F. C.; Garay, M. J.; Xu, F.; Davis, A. B.; Rheingans, B. E.; Chipman, R. A.

    2015-12-01

    The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) aims at characterizing atmospheric aerosols and clouds using highly accurate imaging polarimetry. The instrument is deployed regularly onboard the NASA ER2 high-altitude aircraft, which is an ideal testbed for satellite remote sensing. Flying at 20 km altitude, AirMSPI's pushbroom camera typically provides 11×11 km images at 10 m resolution. The target is observed from multiple along-track angles within ±67° using a gimbal mount. Eight spectral bands within 355-935 nm are recorded simultaneously in different detector rows, 3 of which also measure linear polarization: 470, 660 and 865 nm. Photoelastic modulators (PEMs) encode the polarized and total intensities in each polarimetric pixel as the amplitude and offset of a wavelike intensity pattern, such that the ratio of the two is insensitive to pixel-to-pixel differences. This enables an accuracy in the degree of linear polarization of ~0.001, as measured in the lab. To maintain this accuracy in-flight, an optical probe continuously monitors the PEMs' retardances and controls their driving signals. Before and after observing a target, the instrument also observes a validator, which is an extended, polarized light source, located inside the instrument housing. These data are now incorporated in the data processing pipeline to further improve the calibration of the modulation functions. Highly polarized pixels in Earth data are utilized to transfer the validator results to meet the illumination in Earth scenes, as well as to make fine adjustments at higher temporal resolution. The reprocessed polarization products for the PODEX campaign show significant improvements when intercompared with the Research Scanning Polarimeter (RSP, Goddard Institute for Space Studies). We currently evaluate the impact of the on-board polarimetric calibration on aerosol retrievals, and compare against AERONET reference measurements.

  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. The Martian polar cap - Radiative effects of ozone, clouds, and airborne dust

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1990-01-01

    The solar and thermal flux striking the polar cap of Mars is computed for various ozone, dust, and cloud abundances and for three solar zenith angles. Ozone does not significantly affect the total energy budget of the polar cap. Hence the observed hemispherical asymmetry in ozone abundance causes only an insignificant hemispherical asymmetry in the polar caps. Vertical optical depths of dust and cloud ranging from zero to 1 cause little change in the total flux absorbed by the polar cap near its edge but increase the absorbed flux significantly as one travels poleward. Hemispherical asymmetries in dust abundance, cloud cover, and surface pressure combine to cause a significant hemispherical asymmetry in the total flux absorbed by the residual polar caps, which helps to explain the dichotomy in the residual polar caps on Mars. Other processes which affect the energy budget of the polar cap are proposed and reviewed, particularly with respect to their interaction with the radiative effects of clouds and dust.

  14. The Importance and Technology for Measuring Atmospheric Humidity in Airborne Applications

    NASA Astrophysics Data System (ADS)

    Bozóki, Zoltán; Tátrai, Dávid; Gulyás, Gábor; Varga, Attila; Szabó, Gábor

    2013-04-01

    The concentrations of atmospheric water vapour (i.e. humidity) and total water (i.e. water vapour plus liquid water and ice particles) are crucially important parameters for weather forecast and climate research, while these substances also play dominant roles in aircraft icing and contrail formation. Their concentration varies over more than three orders of magnitudes in the troposphere and stratosphere with high temporal and spatial variation especially when being measured by an instrument operated on-board of a research or commercial aircraft. Therefore an instrument for their measurement has to have short response time, long-term maintenance free operation, small size, low weight, as well as accurate and reliable operation even under extreme conditions. We have developed a diode laser based dual channel instrument (Hilase-Hygro) which operates on a special type of optical absorption methods (i.e. the photoacoustic principle) and which can measure the concentration of water vapour and total water simultaneously while meeting the strictest requirements listed above. One of our instruments is in operation as a part of an automatic laboratory deployed intermittently into the cargo bay of a passenger aircraft within the framework of the CARIBIC project since 2002. Other instrument takes part in various measurement campaigns within the framework of the EUFAR (European Facility for Airborne Research) project. Recently the instrument has been improved in several topics: The wavelength of the applied laser now can be locked with 10^-8 relative accuracy, what results a maximum of 0.1% error in the measured optical absorption, i.e. in the measured humidity levels. The calibration method was also improved, what also increased the performance of the whole instrument. This new calibration method gives the possibility for real time mixing ratio calculation both for water vapour and total water content. Altogether now the instrument is capable for measuring humidity with 1

  15. Characterizing the impact of urban emissions on regional aerosol particles; airborne measurements during the MEGAPOLI experiment

    NASA Astrophysics Data System (ADS)

    Freney, E. J.; Sellegri, K.; Canonaco, F.; Colomb, A.; Borbon, A.; Michoud, V.; Doussin, J.-F.; Crumeyrolle, S.; Amarouch, N.; Pichon, J.-M.; Prévôt, A. S. H.; Beekmann, M.; Schwarzenböeck, A.

    2013-09-01

    The MEGAPOLI experiment took place in July 2009. The aim of this campaign was to study the aging and reactions of aerosol and gas-phase emissions in the city of Paris. Three ground-based measurement sites and several mobile platforms including instrument equipped vehicles and the ATR-42 aircraft were involved. We present here the variations in particle- and gas-phase species over the city of Paris using a combination of high-time resolution measurements aboard the ATR-42 aircraft. Particle chemical composition was measured using a compact time-of-flight aerosol mass spectrometer (C-ToF-AMS) giving detailed information of the non-refractory submicron aerosol species. The mass concentration of BC, measured by a particle absorption soot photometer (PSAP), was used as a marker to identify the urban pollution plume boundaries. Aerosol mass concentrations and composition were affected by air-mass history, with air masses that spent longest time over land having highest fractions of organic aerosol and higher total mass concentrations. The Paris plume is mainly composed of organic aerosol (OA), black carbon and nitrate aerosol, as well as high concentrations of anthropogenic gas-phase species such as toluene, benzene, and NOx. Using BC and CO as tracers for air-mass dilution, we observe the ratio of ΔOA / ΔBC and ΔOA / ΔCO increase with increasing photochemical age (-log(NOx / NOy). Plotting the equivalent ratios for the Positive Matrix Factorization (PMF) resolved species (LV-OOA, SV-OOA, and HOA) illustrate that the increase in OA is a result of secondary organic aerosol (SOA). Within Paris the changes in the ΔOA / ΔCO are similar to those observed during other studies in Mexico city, Mexico and in New England, USA. Using the measured VOCs species together with recent organic aerosol formation yields we predicted ~ 50% of the measured organics. These airborne measurements during the MEGAPOLI experiment show that urban emissions contribute to the formation of OA

  16. Coordinated Airborne, Spaceborne, and Ground-Based Measurements of Massive, Thick Aerosol Layers During the Dry Season in Southern Africa

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Redemann, J.; Russell, P. B.; Hobbs, P. V.; Hlavka, D. L.; McGill, M. J.; Holben, B. N.; Welton, E. J.; Campbell, J.; Torres, O.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    During the dry-season airborne campaign of the Southern African Regional Science Initiative (SAFARI 2000), unique coordinated observations were made of massive, thick aerosol layers. These layers were often dominated by aerosols from biomass burning. We report on airborne Sunphotometer measurements of aerosol optical depth (lambda=354-1558 nm), columnar water vapor, and vertical profiles of aerosol extinction and water vapor density that were obtained aboard the University of Washington's Convair-580 research aircraft. We compare these with ground-based AERONET Sun/sky radiometer results, with ground based lidar data MPL-Net), and with measurements from a downward-pointing lidar aboard the high-flying NASA ER-2 aircraft. Finally, we show comparisons between aerosol optical depths from the Sunphotometer and those retrieved over land and over water using four spaceborne sensors (TOMS (Total Ozone Mapping Spectrometer), MODIS (Moderate Resolution Imaging Spectrometer), MISR (Multiangle Imaging Spectroradiometer) and ATSR-2 (Along Track Scanning Radiometer)).

  17. Coordinated Airborne, Spaceborne and Ground-based Measurements of Massive Thick Aerosol Layers during the Dry Season in Southern Africa

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Redemann, J.; Russell, P. B.; Hobbs, P. V.; Hlavka, D. L.; McGill, M. J.; Holben, B. N.; Welton, E. J.; Campbell, J. R.; Torres, O.

    2003-01-01

    During the dry season airborne campaign of the Southern African Regional Science Initiative (SAFARI 2000), coordinated observations were made of massive thick aerosol layers. These layers were often dominated by aerosols from biomass burning. We report on airborne Sun photometer measurements of aerosol optical depth (lambda = 0.354- 1.557 microns), columnar water vapor, and vertical profiles of aerosol extinction and water vapor density that were obtained aboard the University of Washington's Convair-580 research aircraft. We compare these with ground-based AERONET Sun/sky radiometer results, with ground based lidar data (MPL-Net), and with measurements from a downward pointing lidar aboard the high-flying NASA ER-2 aircraft. Finally, we show comparisons between aerosol optical depths fiom the Sun photometer and those retrieved over land and over water using four spaceborne sensors (TOMS, MODIS, MISR, and ATSR-2).

  18. Method and apparatus for measuring electromagnetic radiation

    NASA Technical Reports Server (NTRS)

    Been, J. F. (Inventor)

    1973-01-01

    An apparatus and method are described in which the capacitance of a semiconductor junction subjected to an electromagnetic radiation field is utilized to indicate the intensity or strength of the radiation.

  19. SUMER: Solar Ultraviolet Measurements of Emitted Radiation

    NASA Technical Reports Server (NTRS)

    Wilhelm, K.; Axford, W. I.; Curdt, W.; Gabriel, A. H.; Grewing, M.; Huber, M. C. E.; Jordan, M. C. E.; Lemaire, P.; Marsch, E.; Poland, A. I.

    1988-01-01

    The SUMER (solar ultraviolet measurements of emitted radiation) experiment is described. It will study flows, turbulent motions, waves, temperatures and densities of the plasma in the upper atmosphere of the Sun. Structures and events associated with solar magnetic activity will be observed on various spatial and temporal scales. This will contribute to the understanding of coronal heating processes and the solar wind expansion. The instrument will take images of the Sun in EUV (extreme ultra violet) light with high resolution in space, wavelength and time. The spatial resolution and spectral resolving power of the instrument are described. Spectral shifts can be determined with subpixel accuracy. The wavelength range extends from 500 to 1600 angstroms. The integration time can be as short as one second. Line profiles, shifts and broadenings are studied. Ratios of temperature and density sensitive EUV emission lines are established.

  20. Analyzing carbon dioxide and methane emissions in California using airborne measurements and model simulations

    NASA Astrophysics Data System (ADS)

    Johnson, M. S.; Yates, E. L.; Iraci, L. T.; Jeong, S.; Fischer, M. L.

    2013-12-01

    Greenhouse gas (GHG) concentrations have increased over the past decades and are linked to global temperature increases and climate change. These changes in climate have been suggested to have varying effects, and uncertain consequences, on agriculture, water supply, weather, sea-level rise, the economy, and energy. To counteract the trend of increasing atmospheric concentrations of GHGs, the state of California has passed the California Global Warming Act of 2006 (AB-32). This requires that by the year 2020, GHG (e.g., carbon dioxide (CO2) and methane (CH4)) emissions will be reduced to 1990 levels. To quantify GHG fluxes, emission inventories are routinely compiled for the State of California (e.g., CH4 emissions from the California Greenhouse Gas Emissions Measurement (CALGEM) Project). The major sources of CO2 and CH4 in the state of California are: transportation, electricity production, oil and gas extraction, cement plants, agriculture, landfills/waste, livestock, and wetlands. However, uncertainties remain in these emission inventories because many factors contributing to these processes are poorly quantified. To alleviate these uncertainties, a synergistic approach of applying air-borne measurements and chemical transport modeling (CTM) efforts to provide a method of quantifying local and regional GHG emissions will be performed during this study. Additionally, in order to further understand the temporal and spatial distributions of GHG fluxes in California and the impact these species have on regional climate, CTM simulations of daily variations and seasonality of total column CO2 and CH4 will be analyzed. To assess the magnitude and spatial variation of GHG emissions and to identify local 'hot spots', airborne measurements of CH4 and CO2 were made by the Alpha Jet Atmospheric eXperiment (AJAX) over the San Francisco Bay Area (SFBA) and San Joaquin Valley (SJV) in January and February 2013 during the Discover-AQ-CA study. High mixing ratios of GHGs were

  1. Characterizing the impact of urban emissions on regional aerosol particles: airborne measurements during the MEGAPOLI experiment

    NASA Astrophysics Data System (ADS)

    Freney, E. J.; Sellegri, K.; Canonaco, F.; Colomb, A.; Borbon, A.; Michoud, V.; Doussin, J.-F.; Crumeyrolle, S.; Amarouche, N.; Pichon, J.-M.; Bourianne, T.; Gomes, L.; Prevot, A. S. H.; Beekmann, M.; Schwarzenböeck, A.

    2014-02-01

    yields, we were able to predict ~50% of the measured organics. These airborne measurements during the MEGAPOLI experiment show that urban emissions contribute to the formation of OA and have an impact on aerosol composition on a regional scale.

  2. Measuring radiative capture rates at DRAGON

    NASA Astrophysics Data System (ADS)

    Hager, U.; Davids, B.; Fallis, J.; Greife, U.; Hutcheon, D. A.; Rojas, A.; Ruiz, C.

    2013-04-01

    The DRAGON recoil separator facility is located at the ISAC facility at TRIUMF, Vancouver. It is designed to measure radiative alpha and proton capture reactions of astrophysical importance in inverse kinematics. The Supernanogan ion source at ISAC provides stable beams of high intensities. The DRAGON collaboration has taken advantage of this over the last years by measuring several reactions requiring high-intensity stable oxygen beams. In particular,the ^17O(p,γ) and ^16O(α,γ) reaction rates were recently measured. The former reaction is part of the hot CNO cycle, and strongly influences the abundance of ^18F in classical novae. Because of its relatively long lifetime, ^18F is a possible target for satellite-based gamma-ray spectroscopy. The ^16O(α,γ) reaction plays a role in steady-state helium burning in massive stars, where it follows the ^12C(α,γ) reaction. At astrophysically relevant energies, the reaction proceeds exclusively via direct capture, resulting in a low rate. In both cases, the unique capabilities of DRAGON enabled determination not only of the total reaction rates, but also of decay branching ratios. Results from both experiments will be presented.

  3. Radiation measurement on the International Space Station.

    PubMed

    Akopova, A B; Manaseryan, M M; Melkonyan, A A; Tatikyan, S Sh; Potapov, Yu

    2005-02-01

    The results of an investigation of radiation environment on board the ISS with apogee/perigee of 420/380 km and inclination 51.6 degrees are presented. For measurement of important characteristics of cosmic rays (particles fluxes, LET spectrum, equivalent doses and heavy ions with Z > or = 2) a nuclear photographic emulsion as a controllable threshold detector was used. The use of this detector permits a registration of the LET spectrum of charged particles within wide range of dE/dx and during the last years it has already been successfully used on board the MIR station, Space Shuttles and "Kosmos" spacecrafts. An integral LET spectrum was measured in the range 0.5-2.2 x 10(3) keV/micrometers and the value of equivalent dose 360 microSv/day was estimated. The flux of biologically dangerous heavy particles with Z > or = 2 was measured (3.85 x 10(3) particles/cm2).

  4. Airborne Polarimetric, Two-Color Laser Altimeter Measurements of Lake Ice Cover: A Pathfinder for NASA's ICESat-2 Spaceflight Mission

    NASA Technical Reports Server (NTRS)

    Harding, David; Dabney, Philip; Valett, Susan; Yu, Anthony; Vasilyev, Aleksey; Kelly, April

    2011-01-01

    The ICESat-2 mission will continue NASA's spaceflight laser altimeter measurements of ice sheets, sea ice and vegetation using a new measurement approach: micropulse, single photon ranging at 532 nm. Differential penetration of green laser energy into snow, ice and water could introduce errors in sea ice freeboard determination used for estimation of ice thickness. Laser pulse scattering from these surface types, and resulting range biasing due to pulse broadening, is assessed using SIMPL airborne data acquired over icecovered Lake Erie. SIMPL acquires polarimetric lidar measurements at 1064 and 532 nm using the micropulse, single photon ranging measurement approach.

  5. Dual-channel photoacoustic hygrometer for airborne measurements: background, calibration, laboratory and in-flight intercomparison tests

    NASA Astrophysics Data System (ADS)

    Tátrai, D.; Bozóki, Z.; Smit, H.; Rolf, C.; Spelten, N.; Krämer, M.; Filges, A.; Gerbig, C.; Gulyás, G.; Szabó, G.

    2015-01-01

    This paper describes a tunable diode laser-based dual-channel photoacoustic (PA) humidity measuring system primarily designed for aircraft-based environment research. It is calibrated for total pressure and water vapor (WV) volume mixing ratios (VMRs) possible during airborne applications. WV VMR is calculated by using pressure-dependent calibration curves and a cubic spline interpolation method. Coverage of the entire atmospheric humidity concentration range that might be encountered during airborne measurements is facilitated by applying an automated sensitivity mode switching algorithm. The calibrated PA system was validated through laboratory and airborne intercomparisons, which proved that the repeatability, the estimated accuracy and the response time of the system are 0.5 ppmV or 0.5% of the actual reading (whichever value is the greater), 5% of the actual reading within the VMR range of 1-12 000 ppmV and 2 s, respectively. The upper detection limit of the system is theoretically about 85 000 ppmV, limited only by condensation of water vapor on the walls of the 318 K heated PA cells and inlet lines, and was experimentally verified up to 20 000 ppmV. The unique advantage of the presented system is its applicability for simultaneous water vapor and total water volume mixing ratio measurements.

  6. Surface and Airborne Measurements of Organosulfur and Methanesulfonate Over the Western United States and Coastal Areas

    PubMed Central

    Sorooshian, Armin; Crosbie, Ewan; Maudlin, Lindsay C.; Youn, Jong-Sang; Wang, Zhen; Shingler, Taylor; Ortega, Amber M.; Hersey, Scott; Woods, Roy K.

    2015-01-01

    This study reports on ambient measurements of organosulfur (OS) and methanesulfonate (MSA) over the western United States and coastal areas. Particulate OS levels are highest in summertime, and generally increase as a function of sulfate (a precursor) and sodium (a marine tracer) with peak levels at coastal sites. The ratio of OS to total sulfur (TS) is also highest at coastal sites, with increasing values as a function of Normalized Difference Vegetation Index (NDVI) and the ratio of organic carbon to elemental carbon. Correlative analysis points to significant relationships between OS and biogenic emissions from marine and continental sources, factors that coincide with secondary production, and vanadium due to a suspected catalytic role. A major OS species, methanesulfonate (MSA), was examined with intensive field measurements and the resulting data support the case for vanadium’s catalytic influence. Mass size distributions reveal a dominant MSA peak between aerodynamic diameters of 0.32—0.56 μm at a desert and coastal site with nearly all MSA mass (≥ 84%) in sub-micrometer sizes; MSA:non-sea salt sulfate ratios vary widely as a function of particle size and proximity to the ocean. Airborne data indicate that relative to the marine boundary layer, particulate MSA levels are enhanced in urban and agricultural areas, and also the free troposphere when impacted by biomass burning. Some combination of fires and marine-derived emissions leads to higher MSA levels than either source alone. Finally, MSA differences in cloud water and out-of-cloud aerosol are discussed. PMID:26413434

  7. Coordinated analysis of airborne spectrophotometric measurements from the mid-day auroras

    NASA Technical Reports Server (NTRS)

    Sivjee, G. G.

    1974-01-01

    Measurements made in the midday auroras are analyzed and compared to measurements from the nighttime auroras. The auroral emission features in the UV spectrum, the N2(+)ING, the N22PG, and N2VK bands, are discussed. Spectral profiles of different bands are presented, and intensity distributions are obtained. Three mechanisms are suggested which can account for the marked differences between the intensity distributions of the N2(+)ING bands of the high altitude midday auroras and the low altitude nighttime auroras: (1) differences in vibrational, rotational, and transitional temperatures; (2) resonant scattering of solar radiation; and (3) excitation of slow ions.

  8. Validating Above-cloud Aerosol Optical Depth Retrieved from MODIS using NASA Ames Airborne Sun-Tracking Photometric and Spectrometric (AATS and 4STAR) Measurements

    NASA Astrophysics Data System (ADS)

    Jethva, H. T.; Torres, O.; Remer, L. A.; Redemann, J.; Dunagan, S. E.; Livingston, J. M.; Shinozuka, Y.; Kacenelenbogen, M. S.; Segal-Rosenhaimer, M.

    2014-12-01

    Absorbing aerosols produced from biomass burning and dust outbreaks are often found to overlay the lower level cloud decks as evident in the satellite images. In contrast to the cloud-free atmosphere, in which aerosols generally tend to cool the atmosphere, the presence of absorbing aerosols above cloud poses greater potential of exerting positive radiative effects (warming) whose magnitude directly depends on the aerosol loading above cloud, optical properties of clouds and aerosols, and cloud fraction. In recent years, development of algorithms that exploit satellite-based passive measurements of ultraviolet (UV), visible, and polarized light as well as lidar-based active measurements constitute a major breakthrough in the field of remote sensing of aerosols. While the unprecedented quantitative information on aerosol loading above cloud is now available from NASA's A-train sensors, a greater question remains ahead: How to validate the satellite retrievals of above-cloud aerosols (ACA)? Direct measurements of ACA such as carried out by the NASA Ames Airborne Tracking Sunphotometer (AATS) and Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) can be of immense help in validating ACA retrievals. In this study, we validate the ACA optical depth retrieved using the 'color ratio' (CR) method applied to the MODIS cloudy-sky reflectance by using the airborne AATS and 4STAR measurements. A thorough search of the historic AATS-4STAR database collected during different field campaigns revealed five events where biomass burning, dust, and wildfire-emitted aerosols were found to overlay lower level cloud decks observed during SAFARI-2000, ACE-ASIA 2001, and SEAC4RS-2013, respectively. The co-located satellite-airborne measurements revealed a good agreement (root-mean-square-error<0.1 for Aerosol Optical Depth (AOD) at 500 nm) with most matchups falling within the estimated uncertainties in the MODIS retrievals (-10% to +50%). An extensive validation of

  9. Airborne-Measured Spatially-Averaged Temperature and Moisture Turbulent Structure Parameters Over a Heterogeneous Surface

    NASA Astrophysics Data System (ADS)

    Platis, Andreas; Martinez, Daniel; Bange, Jens

    2014-05-01

    Turbulent structure parameters of temperature and humidity can be derived from scintillometer measurements along horizontal paths of several 100 m to several 10 km. These parameters can be very useful to estimate the vertical turbulent heat fluxes at the surface (applying MOST). However, there are many assumptions required by this method which can be checked using in situ data, e.g. 1) Were CT2 and CQ2 correctly derived from the initial CN2 scintillometer data (structure parameter of density fluctuations or refraction index, respectively)? 2) What is the influence of the surround hetereogeneous surface regarding its footprint and the weighted averaging effect of the scintillometer method 3) Does MOST provide the correct turbulent fluxes from scintillometer data. To check these issues, in situ data from low-level flight measurements are well suited, since research aircraft cover horizontal distances in very short time (Taylor's hypothesis of a frozen turbulence structure can be applyed very likely). From airborne-measured time series the spatial series are calculated and then their structure functions that finally provide the structure parameters. The influence of the heterogeneous surface can be controlled by the definition of certain moving-average window sizes. A very useful instrument for this task are UAVs since they can fly very low and maintain altitude very precisely. However, the data base of such unmanned operations is still quite thin. So in this contribution we want to present turbulence data obtained with the Helipod, a turbulence probe hanging below a manned helicopter. The structure parameters of temperature and moisture, CT2 and CQ2, in the lower convective boundary layer were derived from data measured using the Helipod in 2003. The measurements were carried out during the LITFASS03 campaign over a heterogeneous land surface around the boundary-layer field site of the Lindenberg Meteorological Observatory-Richard-Aßmann-Observatory (MOL) of the

  10. ACE-Asia Aerosol Optical Depth and Water Vapor Measured by Airborne Sunphotometers and Related to Other Measurements and Calculations

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, P. B.; Schmid, B.; Redemann, J.; Eilers, J. A.; Ramirez, S. A.; Kahn, R.; Hegg, D.; Pilewskie, P.; Anderson, T.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    In the Spring 2001 phase of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia), the 6-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) operated on 15 of the 19 research flights of the NCAR C-130, while its 14-channel counterpart (AATS- 14) flew successfully on all 18 research flights of the CIRPAS Twin Otter. ACE-Asia studied aerosol outflow from the Asian continent to the Pacific basin. It was designed to integrate suborbital and satellite measurements and models so as to reduce the uncertainty in calculations of the climate forcing due to aerosols. AATS-6 and AATS-14 measured solar beam transmission at 6 and 14 wavelengths (380-1021 and 354-1558 nm, respectively), yielding aerosol optical depth (AOD) spectra and column water vapor (CWV). Vertical differentiation in profiles yielded aerosol extinction spectra and water vapor concentration. The wavelength dependence of these AOD and extinction spectra indicates that supermicron dust was often a major component of the ACE-Asia aerosol. Frequently this dust-containing aerosol extended to high altitudes. For example, in AATS- 14 profiles analyzed to date, 36% of full-column AOD at 525 nm was above 3 km. In contrast, only 10% of CWV was above 3 km. Analyses and applications of AATS-6 and AATS-14 data to date include comparisons to (i) extinction products derived using in situ measurements, (ii) extinction profiles derived from lidar measurements, and (iii) AOD retrievals from the Multi-angle Imaging Spectro-Radiometer (MISR) aboard the TERRA satellite. Other planned collaborative studies include comparisons to results from size spectrometers, chemical measurements, other satellite sensors, flux radiometers, and chemical transport models. Early results of these studies will be presented.

  11. Retrieval of ozone column content from airborne Sun photometer measurements during SOLVE II: comparison with coincident satellite and aircraft measurements

    NASA Astrophysics Data System (ADS)

    Livingston, J. M.; Schmid, B.; Russell, P. B.; Eilers, J. A.; Kolyer, R. W.; Redemann, J.; Ramirez, S. R.; Yee, J.-H.; Swartz, W. H.; Trepte, C. R.; Thomason, L. W.; Pitts, M. C.; Avery, M. A.; Randall, C. E.; Lumpe, J. D.; Bevilacqua, R. M.; Bittner, M.; Erbertseder, T.; McPeters, R. D.; Shetter, R. E.; Browell, E. V.; Kerr, J. B.; Lamb, K.

    2005-08-01

    During the 2003 SAGE (Stratospheric Aerosol and Gas Experiment) III Ozone Loss and Validation Experiment (SOLVE) II, the fourteen-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was mounted on the NASA DC-8 aircraft and measured spectra of total and aerosol optical depth (TOD and AOD) during the sunlit portions of eight science flights. Values of ozone column content above the aircraft have been derived from the AATS-14 measurements by using a linear least squares method that exploits the differential ozone absorption in the seven AATS-14 channels located within the Chappuis band. We compare AATS-14 columnar ozone retrievals with temporally and spatially near-coincident measurements acquired by the SAGE III and the Polar Ozone and Aerosol Measurement (POAM) III satellite sensors during four solar occultation events observed by each satellite. RMS differences are 19 DU (7% of the AATS value) for AATS-SAGE and 10 DU (3% of the AATS value) for AATS-POAM. In these checks of consistency between AATS-14 and SAGE III or POAM III ozone results, the AATS-14 analyses use airmass factors derived from the relative vertical profiles of ozone and aerosol extinction obtained by SAGE III or POAM III.

    We also compare AATS-14 ozone retrievals for measurements obtained during three DC-8 flights that included extended horizontal transects with total column ozone data acquired by the Total Ozone Mapping Spectrometer (TOMS) and the Global Ozone Monitoring Experiment (GOME) satellite sensors. To enable these comparisons, the amount of ozone in the column below the aircraft is estimated either by assuming a climatological model or by combining SAGE and/or POAM data with high resolution in-situ ozone measurements acquired by the NASA Langley Research Center chemiluminescent ozone sensor, FASTOZ, during the aircraft vertical profile at the start or end of each flight. Resultant total column ozone values agree with corresponding TOMS and GOME

  12. Oceanic radiance model development and validation: application of airborne active-passive ocean color spectral measurements.

    PubMed

    Hoge, F E; Swift, R; Yungel, J

    1995-06-20

    It is shown that airborne active-passive (laser-solar) ocean color data can be used to develop and validate oceanic radiance models. The two principal inputs to the oceanic radiance model, chlorophyll pigment and incident solar irradiance, are obtained from a nadir-viewing laser-induced fluorescence spectrometer and a zenith-viewing radiometer, respectively. The computed water-leaving radiances are validated by comparison with the calibrated output of a separate nadir-viewing radiometer subsystem. In the North Atlantic Ocean, the calculated and the observed airborne radiances are found to compare very favorably for the 443-, 520-, and 550-nm wavelengths over an ∼ 170-km flight track east of St. John's, Newfoundland. The results further suggest that the semianalytical radiance model of ocean color, the airborne active (laser) fluorescence spectrometer, and the passive (solar) radiometric instrumentation are all remarkably precise.

  13. 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

  14. Unique airborne measurements at the tropopause of Fukushima Xe-133, aerosol, and aerosol precursors indicate aerosol formation via homogeneous and cosmic ray induced nucleation

    NASA Astrophysics Data System (ADS)

    Schlager, Hans; Arnold, Frank; Aufmhoff, Heinfried; Minikin, Andreas; Baumann, Robert; Simgen, Hardy; Lindemann, Stefan; Rauch, Ludwig; Kaether, Frank; Pirjola, Liisa; Schumann, Ulrich

    2014-05-01

    We report unique airborne measurements, at the tropopause, of the Fukushima radio nuclide Xe-133, aerosol particles (size, shape, number concentration, volatility), aerosol precursor gases (particularly SO2, HNO3, H2O). Our measurements and accompanying model simulations indicate homogeneous and cosmic ray induced aerosol formation at the tropopause. Using an extremely sensitive detection method, we managed to detect Fukushima Xe-133, an ideal transport tracer, at and even above the tropopause. To our knowledge, these airborne Xe-133 measurements are the only of their kind. Our investigations represent a striking example how a pioneering measurement of a Fukshima radio nuclide, employing an extremely sensitive method, can lead to new insights into an important atmospheric process. After the Fukushima accidential Xe-133 release (mostly during 11-15 March 2011), we have conducted two aircraft missions, which took place over Central Europe, on 23 March and 11 April 2011. In the air masses, encountered by the research aircraft on 23 March, we have detected Fukushima Xe-133 by an extremely sensitive method, at and even above the tropopause. Besides increased concentrations of Xe-133, we have detected also increased concentrations of the gases SO2, HNO3, and H2O. The Xe-133 data and accompanying transport model simulations indicate that a West-Pacific Warm Conveyor Belt (WCB) lifted East-Asian planetary boundary layer air to and even above the tropopause, followed by relatively fast quasi-horizontal advection to Europe. Along with Xe-133, anthropogenic SO2, NOx (mostly released from East-Asian ground-level combustion sources), and warer vapour were also lifted by the WCB. After the lift, SO2 and NOx experienced efficient solar UV-radiation driven conversion to the important aerosol precursors gases H2SO4 and HNO3. Our investigations indicate that, increased concentrations of the gases SO2, HNO3, and H2O promoted homogeneous and cosmic ray induced aerosol formation at and

  15. 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

  16. Using airborne measurements and modelling to determine the leak rate of the Elgin platform in 2012

    NASA Astrophysics Data System (ADS)

    Mobbs, Stephen D.; Bauguitte, Stephane J.-B.; Wellpott, Axel; O'Shea, Sebastian

    2013-04-01

    On the 25th March 2012 the French multinational oil and gas company Total reported a gas leak at the Elgin gas field in the North Sea following an operation on well G4 on the wellhead platform. During operations to plug and decommission the well methane leaked out which lead to the evacuation of the platform. Total made immense efforts to quickly stop the leak and on the 16th May 2012 the company announced the successful "Top kill". The UK's National Centre for Atmospheric Science (NCAS) supported the Total response to the leak with flights of the Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft. Between the 3rd of April and the 4th of May five missions were flown. The FAAM aircraft was equipped with a Fast Greenhouse Gas Analyser (FGGA, Model RMT-200, Los Gatos Research Inc., US) to measure CH4 mixing ratios with an accuracy of 0.07±2.48 ppbv. The measurement strategy used followed closely NOAA's during the Deepwater Horizon (DWH) spill in the Gulf of Mexico in 2010. The basis of the method is to sample the cross-wind structure of the plume at different heights downwind of the source. The measurements were then fitted to a Gaussian dispersion model which allowed the calculation of the leak rate. The first mission was flown on the 30th March 2012 only 5 days after Total reported the leak. On this day maximum CH4 concentrations exceeded 2800 ppbv. The plume was very distinct and narrow especially near the platform (10km) and it showed almost perfect Gaussian characteristics. Further downwind the plume was split up into several filaments. On this day the CH4 leak rate was estimated to be 1.1 kg/s. Between the 1st and 2nd mission (03/04/2012) the leak rate decreased significantly to about 0.5 kg/s. From the 2nd flight onwards only a minor decrease in leak rate was calculated. The last mission - while the platform was still leaking - was flown on the 4th of May, when the leak rate was estimated to be 0.3 kg/s. The FAAM aircraft measurements

  17. Analysis of airborne Doppler lidar, Doppler radar and tall tower measurements of atmospheric flows in quiescent and stormy weather

    NASA Technical Reports Server (NTRS)

    Bluestein, H. B.; Doviak, R. J.; Eilts, M. D.; Mccaul, E. W.; Rabin, R.; Sundara-Rajan, A.; Zrnic, D. S.

    1986-01-01

    The first experiment to combine airborne Doppler Lidar and ground-based dual Doppler Radar measurements of wind to detail the lower tropospheric flows in quiescent and stormy weather was conducted in central Oklahoma during four days in June-July 1981. Data from these unique remote sensing instruments, coupled with data from conventional in-situ facilities, i.e., 500-m meteorological tower, rawinsonde, and surface based sensors, were analyzed to enhance understanding of wind, waves and turbulence. The purposes of the study were to: (1) compare winds mapped by ground-based dual Doppler radars, airborne Doppler lidar, and anemometers on a tower; (2) compare measured atmospheric boundary layer flow with flows predicted by theoretical models; (3) investigate the kinematic structure of air mass boundaries that precede the development of severe storms; and (4) study the kinematic structure of thunderstorm phenomena (downdrafts, gust fronts, etc.) that produce wind shear and turbulence hazardous to aircraft operations. The report consists of three parts: Part 1, Intercomparison of Wind Data from Airborne Lidar, Ground-Based Radars and Instrumented 444 m Tower; Part 2, The Structure of the Convective Atmospheric Boundary Layer as Revealed by Lidar and Doppler Radars; and Part 3, Doppler Lidar Observations in Thunderstorm Environments.

  18. Pulsed airborne lidar measurements of atmospheric optical depth using the Oxygen A-band at 765 nm.

    PubMed

    Riris, Haris; Rodriguez, Michael; Allan, Graham R; Hasselbrack, William; Mao, Jianping; Stephen, Mark; Abshire, James

    2013-09-01

    We report on an airborne demonstration of atmospheric oxygen optical depth measurements with an IPDA lidar using a fiber-based laser system and a photon counting detector. Accurate knowledge of atmospheric temperature and pressure is required for NASA's Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission, and climate modeling studies. The lidar uses a doubled erbium-doped fiber amplifier and single photon-counting detector to measure oxygen absorption at 765 nm. Our results show good agreement between the experimentally derived differential optical depth measurements with the theoretical predictions for aircraft altitudes from 3 to 13 km.

  19. Space life sciences: radiation risk assessment and radiation measurements in low Earth orbit.

    PubMed

    2004-01-01

    The volume contains papers presented at COSPAR symposia in October 2002 about radiation risk assessment and radiation measurements in low Earth orbit. The risk assessment symposium brought together multidisciplinary expertise including physicists, biologists, and theoretical modelers. Topics included current knowledge about known and predicted radiation environments, radiation shielding, physics cross section models, improved ion beam transport codes, biological demonstrations of specific shielding materials and applications to a manned mission to Mars, advancements in biological measurement of radiation-induced protein expression profiles, and integration of physical and biological parameters to assess key elements of radiation risk. Papers from the radiation measurements in low Earth orbit symposium included data about dose, linear energy transfer spectra, and charge spectra from recent measurements on the International Space Station (ISS), comparison between calculations and measurements of dose distribution inside a human phantom and the neutron component inside the ISS; and reviews of trapped antiprotons and positrons inside the Earth's magnetosphere.

  20. Flux Of Carbon from an Airborne Laboratory (FOCAL): Synergy of airborne and surface measures of carbon emission and isotopologue content from tundra landscape in Alaska

    NASA Astrophysics Data System (ADS)

    Dobosy, R.; Dumas, E.; Sayres, D. S.; Kochendorfer, J.

    2013-12-01

    Arctic tundra, recognized as a potential major source of new atmospheric carbon, is characterized by low topographic relief and small-scale heterogeneity consisting of small lakes and intervening tundra vegetation. This fits well the flux-fragment method (FFM) of analysis of data from low-flying aircraft. The FFM draws on 1)airborne eddy-covariance flux measurements, 2)a classified surface-characteristics map (e.g. open water vs tundra), 3)a footprint model, and 4)companion surface-based eddy-covariance flux measurements. The FOCAL, a collaboration among Harvard University's Anderson Group, NOAA's Atmospheric Turbulence and Diffusion Division (ATDD), and Aurora Flight Sciences, Inc., made coordinated flights in 2013 August with a collaborating surface site. The FOCAL gathers not only flux data for CH4 and CO2 but also the corresponding carbon-isotopologue content of these gases. The surface site provides a continuous sample of carbon flux from interstitial tundra over time throughout the period of the campaign. The FFM draws samples from the aircraft data over many instances of tundra and also open water. From this we will determine how representative the surface site is of the larger area (100 km linear scale), and how much the open water differs from the tundra as a source of carbon.

  1. Airborne measurements of the atmospheric emissions from a fuel ethanol refinery

    NASA Astrophysics Data System (ADS)

    de Gouw, J. A.; McKeen, S. A.; Aikin, K. C.; Brock, C. A.; Brown, S. S.; Gilman, J. B.; Graus, M.; Hanisco, T.; Holloway, J. S.; Kaiser, J.; Keutsch, F. N.; Lerner, B. M.; Liao, J.; Markovic, M. Z.; Middlebrook, A. M.; Min, K.-E.; Neuman, J. A.; Nowak, J. B.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Trainer, M.; Veres, P. R.; Warneke, C.; Welti, A.; Wolfe, G. M.

    2015-05-01

    Ethanol made from corn now constitutes approximately 10% of the fuel used in gasoline vehicles in the U.S. The ethanol is produced in over 200 fuel ethanol refineries across the nation. We report airborne measurements downwind from Decatur, Illinois, where the third largest fuel ethanol refinery in the U.S. is located. Estimated emissions are compared with the total point source emissions in Decatur according to the 2011 National Emissions Inventory (NEI-2011), in which the fuel ethanol refinery represents 68.0% of sulfur dioxide (SO2), 50.5% of nitrogen oxides (NOx = NO + NO2), 67.2% of volatile organic compounds (VOCs), and 95.9% of ethanol emissions. Emissions of SO2 and NOx from Decatur agreed with NEI-2011, but emissions of several VOCs were underestimated by factors of 5 (total VOCs) to 30 (ethanol). By combining the NEI-2011 with fuel ethanol production numbers from the Renewable Fuels Association, we calculate emission intensities, defined as the emissions per ethanol mass produced. Emission intensities of SO2 and NOx are higher for plants that use coal as an energy source, including the refinery in Decatur. By comparing with fuel-based emission factors, we find that fuel ethanol refineries have lower NOx, similar VOC, and higher SO2 emissions than from the use of this fuel in vehicles. The VOC emissions from refining could be higher than from vehicles, if the underestimated emissions in NEI-2011 downwind from Decatur extend to other fuel ethanol refineries. Finally, chemical transformations of the emissions from Decatur were observed, including formation of new particles, nitric acid, peroxyacyl nitrates, aldehydes, ozone, and sulfate aerosol.

  2. Mercury emissions from burning of biomass from temperate North American forests: laboratory and airborne measurements

    NASA Astrophysics Data System (ADS)

    Friedli, H. R.; Radke, L. F.; Lu, J. Y.; Banic, C. M.; Leaitch, W. R.; MacPherson, J. I.

    The emission of mercury from biomass burning was investigated in laboratory experiments and the results confirmed in airborne measurements on a wildfire near Hearst, Ont. Mercury contained in vegetation (live, dead, coniferous, deciduous) was essentially completely released in laboratory burns in the form of gaseous elemental mercury and mercury contained in particles. Replicate burns of dry Ponderosa needles indicated a linear relationship between emitted mercury and fuel mass loss. Regionally collected fuels showed the same behavior as the replicate burns, i.e. essentially total removal of mercury. Mercury released from fuel could be accounted for as gaseous and particulate mercury in the smoke. The mercury content of regionally collected fuels varied between 14 and 70 ng/g on a dry mass (dm) basis. The smoke plume from a small wildfire was investigated with a research aircraft yielding a mean output of 0.15±0.02 ng/m 3 of elemental mercury for each ppm of CO 2 emitted. The particulate mercury determined by sampling at specific points in the plume was <0.083 ng/m 3 compared to elemental mercury of 0.56 ng/m 3 for the same air, supporting the conclusion that most of the mercury was emitted in the gaseous elemental form. Emission factors for the high/low mercury content samples of the laboratory burns were 14-71×10 -6 and 112×10 -6 g Hg/kg (dm) fuel for the wildfire. The difference is believed to be the contribution of mercury released from fire-heated soil. Mercury budgets extrapolated from this single wildfire gave upper emission limits of 66 t/yr for temperate/boreal forests. This large source estimate must be refined and included in future regional and global models. Forests are sinks for mercury already in the atmosphere, thus the wildfire "source" is part of the overall cycling of mercury originating from other sources.

  3. Airborne measurement of ozone and precursors near Houston, Texas on June 11, 1997

    SciTech Connect

    Valente, R.J.; Shauck, M.; Zanin, G.; Pendleton, D.; Lambeth, B.; Price, J.; Rozacky, K.

    1998-12-31

    The advent of revised ambient air quality standards for ozone has rekindled interest in the formation and transport of ozone in urban and power plant plumes. The State of Texas, Baylor University, and the Tennessee Valley Authority are currently involved in a cooperative airborne air pollution monitoring program designed to study the formation and transport of ozone and precursors in Texas. A King Air model A90 aircraft has been outfitted with continuous instrumentation for ozone, NO{sub x}, NO, SO{sub 2}, hydrocarbons, light scattering, temperature, altitude, and position. This aircraft has logged 45 flights with over 200 hours of flight data for the 1997 field season. This work represents one of the first successful applications of an air pollution research aircraft for on-call use by a state regulatory authority. This paper presents results from a case study of ozone formation and transport in the Houston, Texas area on June 11, 1997. The case study documents the magnitude of an elevated ozone episode in the Houston area including a discussion of the role of transported versus locally produced ozone. Both vertical and horizontal variability of ozone and precursors are studied with special emphasis given to the implications of the measurements in light of the revised ambient air quality standard for ozone. The relationship between ozone formation and increased NO{sub x} and other precursors is also documented. Also discussed are some of the logistical challenges of an intensive program of this nature. Other objectives of the research and monitoring project are also mentioned including plans to use the Baylor King Air platform to study the transboundary pollutant transport at the US-Mexican border and interregional transport between Texas and other regions of the US.

  4. Tropospheric ozone and aerosols measured by airborne lidar during the 1988 Arctic boundary layer experiment

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Butler, Carolyn F.; Kooi, Susan A.

    1991-01-01

    Ozone (O3) and aerosol distributions were measured from an aircraft using a differential absorption lidar (DIAL) system as part of the 1988 NASA Global Tropospheric Experiment - Arctic Boundary Layer Experiment (ABLE-3A) to study the sources and sinks of gases and aerosols over the tundra regions of Alaska during the summer. The tropospheric O3 budget over the Arctic was found to be strongly influenced by stratospheric intrusions. Regions of low aerosol scattering and enhanced O3 mixing ratios were usually correlated with descending air from the upper troposphere or lower stratosphere. Several cases of continental polar air masses were examined during the experiment. The aerosol scattering associated with these air masses was very low, and the atmospheric distribution of aerosols was quite homogeneous for those air masses that had been transported over the ice for greater than or = 3 days. The transition in O3 and aerosol distributions from tundra to marine conditions was examined several times. The aerosol data clearly show an abrupt change in aerosol scattering properties within the mixed layer from lower values over the tundra to generally higher values over the water. The distinct differences in the heights of the mixed layers in the two regions was also readily apparent. Several cases of enhanced O3 were observed during ABLE-3 in conjunction with enhanced aerosol scattering in layers in the free atmosphere. Examples are presented of the large scale variations of O3 and aerosols observed with the airborne lidar system from near the surface to above the tropopause over the Arctic during ABLE-3.

  5. Nitrous Oxide (N2O) Emissions from California based on 2010 CalNex Airborne Measurements

    NASA Astrophysics Data System (ADS)

    Xiang, B.; Miller, S.; Kort, E. A.; Santoni, G. W.; Daube, B.; Commane, R.; Angevine, W. M.; Ryerson, T. B.; Trainer, M.; Andrews, A. E.; Nehrkorn, T.; Tian, H.; Wofsy, S. C.

    2012-12-01

    Nitrous oxide (N2O) is an important gas for climate and for stratospheric chemistry, with an atmospheric lifetime exceeding 100 years. Global concentrations have increased steadily since the 18th century, apparently due to human-associated emissions, principally from application of nitrogen fertilizers. However, quantitative studies of agricultural emissions at large spatial scales are lacking, inhibited by the difficulty of measuring small enhancements of atmospheric concentrations. Here we derive regional emission rates for N2O in the Central Valley of California, based on analysis of in-situ airborne atmospheric observations collected using a quantum cascade laser spectrometer. The data were obtained on board the NOAA P-3 research aircraft during the CalNex (California Research at the Nexus of Air Quality and Climate Change) program in May and June, 2010. We coupled WRF (Weather Research and Forecasting) model to STILT (Stochastic Time-Inverted Lagrangian Transport) to link our in-situ observations to surface emissions, and then used a variety of statistical methods to identify source areas and to extract optimized emission rates from the inversion. Our results support the view that fertilizer application is the largest source of N2O in the Central Valley. But the spatial distribution of derived surface emissions, based on California land use and activity maps, was very different than indicated in the leading emissions inventory (EDGAR 4.0), and our estimated total emission flux of N2O for California during the study period was 3 - 4 times larger than EDGAR and other inventories.

  6. Aerosol, surface, and cloud optical parameters derived from airborne spectral actinic flux: measurement comparison with other methods

    NASA Astrophysics Data System (ADS)

    Stark, H.; Bierwirth, E.; Schmidt, S.; Kindel, B. C.; Pilewskie, P.; Lack, D. A.; Madronich, S.; Parrish, D. D.

    2009-12-01

    Optical parameters of aerosols, surfaces, and clouds are essential for an accurate description of Earth’s radiative balance. We will present values for such parameters derived from spectral actinic flux measured on board the NOAA WP-3D aircraft during the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) study in April 2008. We will compare these measurements to results obtained from other instruments on board the same aircraft, such as the Solar Spectral Flux Radiometer (SSFR) for irradiance measurements and aerosol extinction and absorption measurements by cavity ring-down and Particle Soot Absorption Photometer (PSAP). Actinic flux is sensitive to these parameters and can be used to measure them directly in the atmosphere without in-situ sampling methods required. We will describe the specifics of the actinic flux measurements, show advantages and disadvantages of this measurement technique, and compare results with other techniques. Furthermore, we will compare our measurements with model calculations from radiative transfer models such as the Tropospheric Ultraviolet and Visible (TUV) radiation model, the widely used library of radiative transfer (libradtran) model, and a Monte-Carlo radiation model (GRIMALDI). Also, we will investigate satellite measurements to constrain the radiation measurements to general radiation conditions in the arctic and to compare the results to aerosol optical depth retrievals. In particular, we will show results for surface albedo of the Arctic Ocean ice surface, extinction and absorption of Arctic haze layers, and optical thickness and albedo measurements of clouds.

  7. Photoreactivation in Airborne Mycobacterium parafortuitum

    PubMed Central

    Peccia, Jordan; Hernandez, Mark

    2001-01-01

    Photoreactivation was observed in airborne Mycobacterium parafortuitum exposed concurrently to UV radiation (254 nm) and visible light. Photoreactivation rates of airborne cells increased with increasing relative humidity (RH) and decreased with increasing UV dose. Under a constant UV dose with visible light absent, the UV inactivation rate of airborne M. parafortuitum cells decreased by a factor of 4 as RH increased from 40 to 95%; however, under identical conditions with visible light present, the UV inactivation rate of airborne cells decreased only by a factor of 2. When irradiated in the absence of visible light, cellular cyclobutane thymine dimer content of UV-irradiated airborne M. parafortuitum and Serratia marcescens increased in response to RH increases. Results suggest that, unlike in waterborne bacteria, cyclobutane thymine dimers are not the most significant form of UV-induced DNA damage incurred by airborne bacteria and that the distribution of DNA photoproducts incorporated into UV-irradiated airborne cells is a function of RH. PMID:11526027

  8. Airborne Measurements of Atmospheric Pressure made Using an IPDA Lidar Operating in the Oxygen A-Band

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Abshire, James B.; Stephen, Mark; Rodriquez, Michael; Allan, Graham; Hasselbrack, William; Mao, Jianping

    2012-01-01

    We report airborne measurements of atmospheric pressure made using an integrated path differential absorption (IPDA) lidar that operates in the oxygen A-band near 765 nm. Remote measurements of atmospheric temperature and pressure are needed for NASA s Active Sensing of CO2 Emissions Over Nights, Days, and Seasons (ASCENDS) mission to measure atmospheric CO2. Accurate measurements of tropospheric CO2 on a global scale are very important in order to better understand its sources and sinks and to improve our predictions of climate change. The goal of ASCENDS is to determine the CO2 dry mixing ratio with lidar measurements from space at a level of 1 ppm. Analysis to date shows that with current weather models, measurements of both the CO2 column density and the column density of dry air are needed. Since O2 is a stable molecule that uniformly mixed in the atmosphere, measuring O2 absorption in the atmosphere can be used to infer the dry air density. We have developed an airborne (IPDA) lidar for Oxygen, with support from the NASA ESTO IIP program. Our lidar uses DFB-based seed laser diodes, a pulsed modulator, a fiber laser amplifier, and a non-linear crystal to generate wavelength tunable 765 nm laser pulses with a few uJ/pulse energy. The laser pulse rate is 10 KHz, and average transmitted laser power is 20 mW. Our lidar steps laser pulses across a selected line O2 doublet near 764.7 nm in the Oxygen A-band. The direct detection lidar receiver uses a 20 cm diameter telescope, a Si APD detector in Geiger mode, and a multi-channel scalar to detect and record the time resolved laser backscatter in 40 separate wavelength channels. Subsequent analysis is used to estimate the transmission line shape of the doublet for the laser pulses reflected from the ground. Ground based data analysis allows averaging from 1 to 60 seconds to increase SNR in the transmission line shape of the doublet. Our retrieval algorithm fits the expected O2 lineshapes against the measurements and

  9. Proceedings of a Meeting on Traceability for Ionizing Radiation Measurements

    NASA Astrophysics Data System (ADS)

    Heaton, H. T., II

    1982-02-01

    General concepts for traceability were presented from several perspectives. The national standards for radiation dosimetry, radioactivity measurements, and neutron measurements were described. Specific programs for achieving traceability to the national standards for radiation measurements in medical, occupational, and environmental applications were summarized.

  10. Unmanned Airborne System Deployment at Turrialba Volcano for Real Time Eruptive Cloud Measurements

    NASA Astrophysics Data System (ADS)

    Diaz, J. A.; Pieri, D. C.; Fladeland, M. M.; Bland, G.; Corrales, E.; Alan, A., Jr.; Alegria, O.; Kolyer, R.

    2015-12-01

    The development of small unmanned aerial systems (sUAS) with a variety of instrument packages enables in situ and proximal remote sensing measurements of volcanic plumes, even when the active conditions of the volcano do not allow volcanologists and emergency response personnel to get too close to the erupting crater. This has been demonstrated this year by flying a sUAS through the heavy ash driven erupting volcanic cloud of Turrialba Volcano, while conducting real time in situ measurement of gases over the crater summit. The event also achieved the collection of newly released ash samples from the erupting volcano. The interception of the Turrialba ash cloud occurred during the CARTA 2015 field campaign carried out as part of an ongoing program for remote sensing satellite calibration and validation purposes, using active volcanic plumes. These deployments are timed to support overflights of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) onboard the NASA Terra satellite on a bimonthly basis using airborne platforms such as tethered balloons, free-flying fixed wing small UAVs at altitudes up to 12.5Kft ASL within about a 5km radius of the summit crater. The onboard instrument includes the MiniGas payload which consists of an array of single electrochemical and infrared gas detectors (SO2, H2S CO2), temperature, pressure, relative humidity and GPS sensors, all connected to an Arduino-based board, with data collected at 1Hz. Data are both stored onboard and sent by telemetry to the ground operator within a 3 km range. The UAV can also carry visible and infrared cameras as well as other payloads, such as a UAV-MS payload that is currently under development for mass spectrometer-based in situ measurements. The presentation describes the ongoing UAV- based in situ remote sensing validation program at Turrialba Volcano, the results of a fly-through the eruptive cloud, as well as future plans to continue these efforts. Work presented here was

  11. Measurement of Soluble and Total Hexavalent Chromium in the Ambient Airborne Particles in New Jersey

    PubMed Central

    Huang, Lihui; Yu, Chang Ho; Hopke, Philip K.; Lioy, Paul J.; Buckley, Brian T.; Shin, Jin Young; Fan, Zhihua (Tina)

    2015-01-01

    Hexavalent chromium (Cr(VI)) in ambient airborne particulate matter (PM) is a known pulmonary carcinogen and may have both soluble and insoluble forms. The sum of the two forms is defined as total Cr(VI). Currently, there were no methods suitable for large-scale monitoring of total Cr(VI) in ambient PM. This study developed a method to measure total Cr(VI) in ambient PM. This method includes PM collection using a Teflon filter, microwave extraction with 3% Na2CO3-2% NaOH at 95°C for 60 minutes, and Cr(VI) analysis by 1,5-diphenylcarbazide colorimetry at 540 nm. The recoveries of total Cr(VI) were 119.5 ± 10.4% and 106.3 ± 16.7% for the Cr(VI)-certified reference materials, SQC 012 and SRM 2700, respectively. Total Cr(VI) in the reference urban PM (NIST 1648a) was 26.0 ± 3.1 mg/kg (%CV = 11.9%) determined by this method. The method detection limit was 0.33 ng/m3. This method and the one previously developed to measure ambient Cr(VI), which is soluble in pH ~9.0 aqueous solution, were applied to measure Cr(VI) in ambient PM10 collected from three urban areas and one suburban area in New Jersey. The total Cr(VI) concentrations were 1.05–1.41 ng/m3 in the winter and 0.99–1.56 ng/m3 in the summer. The soluble Cr(VI) concentrations were 0.03–0.19 ng/m3 in the winter and 0.12–0.37 ng/m3 in the summer. The summer mean ratios of soluble to total Cr(VI) were 14.3–43.7%, significantly higher than 4.2–14.4% in the winter. The winter concentrations of soluble and total Cr(VI) in the suburban area were significantly lower than in the three urban areas. The results suggested that formation of Cr(VI) via atmospheric chemistry may contribute to the higher soluble Cr(VI) concentrations in the summer. PMID:26120324

  12. Fluorescence Spectra of Individual Flowing Airborne Biological Particles Measured in Real Time

    DTIC Science & Technology

    2001-02-01

    nucleotides, secondary metabolites , and components of culture media (these may have more variability from sample to sample than do the amino acids...Grinshpun, K. Willeke, and E. C. Cole, Characteristics of airborne actinomycete spores. Appl. Environ. Microbiol. 64 (1998), pp 3807–3812. 20. Franc, G. D

  13. A Coordinated Ice-based and Airborne Snow and Ice Thickness Measurement Campaign on Arctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Richter-Menge, J.; Farrell, S.; Elder, B. C.; Gardner, J. M.; Brozena, J. M.

    2011-12-01

    A rare opportunity presented itself in March 2011 when the Naval Research Laboratory (NRL) and NASA IceBridge teamed with scientists from the U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL) to coordinate a multi-scale approach to mapping snow depth and sea ice thickness distribution in the Arctic. Ground-truth information for calibration/validation of airborne and CryoSat-2 satellite data were collected near a manned camp deployed in support of the US Navy's Ice Expedition 2011 (ICEX 2011). The ice camp was established at a location approximately 230 km north of Prudhoe Bay, Alaska, at the edge of the perennial ice zone. The suite of measurements was strategically organized around a 9-km-long survey line that covered a wide range of ice types, including refrozen leads, deformed and undeformed first year ice, and multiyear ice. A highly concentrated set of in situ measurements of snow depth and ice thickness were taken along the survey line. Once the survey line was in place, NASA IceBridge flew a dedicated mission along the survey line, collecting data with an instrument suite that included the Airborne Topographic Mapper (ATM), a high precision, airborne scanning laser altimeter; the Digital Mapping System (DMS), nadir-viewing digital camera; and the University of Kansas ultra-wideband Frequency Modulated Continuous Wave (FMCW) snow radar. NRL also flew a dedicated mission over the survey line with complementary airborne radar, laser and photogrammetric sensors (see Brozena et al., this session). These measurements were further leveraged by a series of CryoSat-2 under flights made in the region by the instrumented NRL and NASA planes, as well as US Navy submarine underpasses of the 9-km-long survey line to collect ice draft measurements. This comprehensive suite of data provides the full spectrum of sampling resolutions from satellite, to airborne, to ground-based, to submarine and will allow for a careful determination of

  14. A comparison of emerging gamma detector technologies for airborne radiation monitoring

    NASA Astrophysics Data System (ADS)

    Bell, S. J.; Aitken-Smith, P.; Beeke, S.; Collins, S. M.; Regan, P. H.; Shearman, R.

    2016-10-01

    This paper presents a comparison of new and emerging gamma detector technologies that have the potential to improve in-situ dose and radioactivity-in-air measurements for national monitoring networks. Five detectors were chosen for investigation; LaBr3(Ce), CeBr3, SiPM-CsI(Tl), Cd(Zn)Te and electromechanically-cooled HPGe. These detectors represent the full range of the price-performance matrix. Comparisons have been made of energy resolution, detection efficiency and minimum detectable activity by exposing each detector to a mixed radionuclide source drop-deposited across a filter. Other factors, such as internal radioactivity, linearity, size and cost have also been considered.

  15. Geltape method for measurement of work related surface contamination with cobalt containing dust: correlation between surface contamination and airborne exposure.

    PubMed Central

    Poulsen, O M; Olsen, E; Christensen, J M; Vinzent, P; Petersen, O H

    1995-01-01

    OBJECTIVES--The geltape method is a new method for optical measurement of total amount of dust on surfaces. The objectives were to study the potential applicability of this method to measurements of work related cobalt exposure during painting of plates with cobalt dye. METHODS--Consecutive series of work related geltape prints were taken from surfaces inside and outside the ventilation cabins of two plate painters during two full working days. The amount of dust picked up by the geltapes was measured optically with a field monitor. Also, personal air samples were collected on filters at the different work processes. In the laboratory the contents of cobalt on the geltape prints and the filters were measured with inductive coupled plasma atomic emission spectroscopy. RESULTS--The key results were: (a) when the geltape prints were taken from surfaces inside the cabins the optically measured area of the geltapes covered with total dust (area (%)) correlated well with the chemically measured amount of cobalt present on the geltapes. Linear correlation coefficient (R2) was 0.91 for geltape prints taken on the floor and 0.94 for prints taken on the ceiling; (b) the cumulative airborne cobalt exposure, calculated from data on work related exposure by personal sampling, correlated with the area (%) of geltape prints taken from the ceiling of the cabin (R2 = 0.98); (c) the geltape method could be used to distinguish both between work processes with different levels of cobalt exposure, and between plate painters subjected to significant differences in airborne cobalt exposure. CONCLUSION--The geltape method could produce measures of the work related exposures as well as whole day exposure for cobalt. The geltape results correlated with measurements of personal airborne cobalt exposure. In this industry the profile of exposure is well-defined in time, and it seems reasonable to apply this fast and low cost method in routine exposure surveillance to obtain a more detailed

  16. New radiosonde techniques to measure radiation profiles through the atmosphere

    NASA Astrophysics Data System (ADS)

    Kräuchi, Andreas; Philipona, Rolf; Romanens, Gonzague; Levrat, Gilbert

    2013-04-01

    Solar and thermal radiation fluxes are usually measured at Earth's surface and at the top of the atmosphere. Here we show radiosonde techniques that allow measuring radiation flux profiles and the radiation budget from the Earth's surface to above 30 km in the stratosphere. During two-hour flights solar shortwave and thermal longwave irradiance, downward and upward, is measured with four individual sensors at one-second resolution, along with standard PTU radiosonde profiles. Daytime and nighttime shortwave and longwave radiation measurements, and 24 hours surface measurements, allow determining radiation budget- and total net radiation profiles through the atmosphere. We use a double balloon technique to prevent pendulum motion during the ascent and to keep the sonde as horizontal as possible. New techniques using auto controlled airplanes are now investigated to retrieve the sonde after release at a certain altitude and to land it if possible at the launch station.

  17. Airborne gravity measurement over sea-ice: The western Weddel Sea

    SciTech Connect

    Brozena, J.; Peters, M. ); LaBrecque, J.; Bell, R.; Raymond, C. )

    1990-10-01

    An airborne gravity study of the western Weddel Sea, east of the Antarctic Peninsula, has shown that floating pack-ice provides a useful radar altimetric reference surface for altitude and vertical acceleration corrections surface for alititude and vertical acceleration corrections to airborne gravimetry. Airborne gravimetry provides an important alternative to satellite altimetry for the sea-ice covered regions of the world since satellite alimeters are not designed or intended to provide accurate geoidal heights in areas where significant sea-ice is present within the radar footprint. Errors in radar corrected airborne gravimetry are primarily sensitive to the variations in the second derivative of the sea-ice reference surface in the frequency pass-band of interest. With the exception of imbedded icebergs the second derivative of the pack-ice surface closely approximates that of the mean sea-level surface at wavelengths > 10-20 km. With the airborne method the percentage of ice coverage, the mixture of first and multi-year ice and the existence of leads and pressure ridges prove to be unimportant in determining gravity anomalies at scales of geophysical and geodetic interest, provided that the ice is floating and not grounded. In the Weddell study an analysis of 85 crosstrack miss-ties distributed over 25 data tracks yields an rms error of 2.2 mGals. Significant structural anomalies including the continental shelf and offsets and lineations interpreted as fracture zones recording the early spreading directions within the Weddell Sea are observed in the gravity map.

  18. Automatic Extraction of Optimal Endmembers from Airborne Hyperspectral Imagery Using Iterative Error Analysis (IEA) and Spectral Discrimination Measurements

    PubMed Central

    Song, Ahram; Chang, Anjin; Choi, Jaewan; Choi, Seokkeun; Kim, Yongil

    2015-01-01

    Pure surface materials denoted by endmembers play an important role in hyperspectral processing in various fields. Many endmember extraction algorithms (EEAs) have been proposed to find appropriate endmember sets. Most studies involving the automatic extraction of appropriate endmembers without a priori information have focused on N-FINDR. Although there are many different versions of N-FINDR algorithms, computational complexity issues still remain and these algorithms cannot consider the case where spectrally mixed materials are extracted as final endmembers. A sequential endmember extraction-based algorithm may be more effective when the number of endmembers to be extracted is unknown. In this study, we propose a simple but accurate method to automatically determine the optimal endmembers using such a method. The proposed method consists of three steps for determining the proper number of endmembers and for removing endmembers that are repeated or contain mixed signatures using the Root Mean Square Error (RMSE) images obtained from Iterative Error Analysis (IEA) and spectral discrimination measurements. A synthetic hyperpsectral image and two different airborne images such as Airborne Imaging Spectrometer for Application (AISA) and Compact Airborne Spectrographic Imager (CASI) data were tested using the proposed method, and our experimental results indicate that the final endmember set contained all of the distinct signatures without redundant endmembers and errors from mixed materials. PMID:25625907

  19. Automatic extraction of optimal endmembers from airborne hyperspectral imagery using iterative error analysis (IEA) and spectral discrimination measurements.

    PubMed

    Song, Ahram; Chang, Anjin; Choi, Jaewan; Choi, Seokkeun; Kim, Yongil

    2015-01-23

    Pure surface materials denoted by endmembers play an important role in hyperspectral processing in various fields. Many endmember extraction algorithms (EEAs) have been proposed to find appropriate endmember sets. Most studies involving the automatic extraction of appropriate endmembers without a priori information have focused on N-FINDR. Although there are many different versions of N-FINDR algorithms, computational complexity issues still remain and these algorithms cannot consider the case where spectrally mixed materials are extracted as final endmembers. A sequential endmember extraction-based algorithm may be more effective when the number of endmembers to be extracted is unknown. In this study, we propose a simple but accurate method to automatically determine the optimal endmembers using such a method. The proposed method consists of three steps for determining the proper number of endmembers and for removing endmembers that are repeated or contain mixed signatures using the Root Mean Square Error (RMSE) images obtained from Iterative Error Analysis (IEA) and spectral discrimination measurements. A synthetic hyperpsectral image and two different airborne images such as Airborne Imaging Spectrometer for Application (AISA) and Compact Airborne Spectrographic Imager (CASI) data were tested using the proposed method, and our experimental results indicate that the final endmember set contained all of the distinct signatures without redundant endmembers and errors from mixed materials.

  20. Measurement of Radiation Pressure in an Ambient Environment

    NASA Astrophysics Data System (ADS)

    Ma, Dakang; Garrett, Joseph; Munday, Jeremy

    2015-03-01

    Light has momentum and thus exerts ``radiation pressure'' when it is reflected or absorbed due to the conservation of momentum. Micromechanical transducers and oscillators are suitable for measurement and utilization of radiation pressure due to their high sensitivities. However, other light-induced mechanical deformations such as photothermal effects often obscure accurate measurements of radiation pressure in these systems. In this work, we investigate the radiation pressure and photothermal force on an uncoated silicon nitride microcantilever under illumination by a 660 nm laser in an ambient environment. To magnify the mechanical effects, the cantilever is driven optically from dc across its resonance frequency, and the amplitude and phase of its oscillation are acquired by an optical beam deflection method and a lockin amplifier. We show that radiation pressure and photothermal effects can be distinguished through the cantilever's frequency response. Furthermore, in a radiation pressure dominant regime, our measurement of the radiation force agrees quantitatively with the theoretical calculation.

  1. Calculation of aerosol backscatter from airborne continuous wave focused CO2 Doppler lidar measurements. I - Algorithm description

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry; Bowdle, David A.; Vaughan, Michael; Brown, Derek W.; Woodfield, Alan A.

    1991-01-01

    Since 1981 the Royal Signals and Radar Establishment and the Royal Aircraft Establishment, United Kindom, have made vertical and horizontal sounding measurements of aerosol backscatter coefficients at 10.6 microns, using an airborne continuous-wave-focused CO2 Doppler lidar, the Laser True Airspeed System (LATAS). In this paper, the heterodyne signal from the LATAS detector is spectrally analyzed. Then, in conjunction with aircraft flight parameters, the data are processed in a six-stage computer algorithm: set search window, search for peak signal, test peak signal, measure total signal, calculate signal-to-noise ratio, and calculate backscatter coefficient.

  2. Airborne measurements of aerosols from burning biomass in Brazil related to the TRACE A experiment

    NASA Astrophysics Data System (ADS)

    Pereira, E. B.; Setzer, A. W.; Gerab, F.; Artaxo, P. E.; Pereira, M. C.; Monroe, G.

    1996-10-01

    Results are reported from an airborne campaign to investigate the impacts of burning biomass upon the loading of lower-tropospheric aerosols and its composition over the Brazilian tropics. The flights, conducted as part of the NASA/Transport and Atmospheric Chemistry Near the Equator-Atlantic (TRACE A) mission, started on September 1, 1992, when the dry (fire) season still prevailed in the central part of Brazil, and ended on September 29. Of the total number of burnings detected in Brazil by the advanced very high resolution radiometer (AVHRR)/NOAA satellite sensor, 74% were concentrated in the states of Amazonas, Maranhão, Mato Grosso, Pará, Roraima, and Tocantins during this period. Aerosol particles were sampled from a twin-engine aircraft in transit and vertical profile flights were made up to 4,000 m altitude. Black carbon measurements made in real time and in areas of burning biomass peaked at ˜2,500 m above the ground, increasing to ˜12,000 ng/m3. In other areas these values were lower by 1 order of magnitude. A condensation nuclei counter measuring small particles (>0.014 μm) produced values ranging from 2,000 to 16,000/cm3 for areas with low and high burning biomass, respectively. Deposition filters in a two-stage cascade impactor, and Nuclepore filters collected aerosols for analysis of 13 elements through particle-induced X ray emissions (PIXE). Primary elements associated with soil dust (Al, Si, Mn, Fe, Ni) prevailed in the aerosol coarse mode (>1 μm) while the fine mode aerosols were enriched in S, K, Br, and Rb, which are tracers normally associated with burning of biomass. The good correlation between fire spot counts, obtained via AVHRR aboard NOAA satellites, and black carbon, counts of small particles and total aerosol mass, suggests the determining of local concentrations of fire-derived aerosol fire emissions by satellite to be a new and useful approach.

  3. Variability in airborne and biological measures of exposure to mercury in the chloralkali industry: implications for epidemiologic studies.

    PubMed Central

    Symanski, E; Sällsten, G; Barregård, L

    2000-01-01

    Exposure assessment is a critical component of epidemiologic studies, and more sophisticated approaches require that variation in exposure be considered. We examined the intra- and interindividual sources of variation in exposure to mercury vapor as measured in air, blood, and urine among four groups of workers during 1990-1997 at a Swedish chloralkali plant. Consistent with the underlying kinetics of mercury in the body, the variability of biological measures was dampened considerably relative to the variation in airborne levels. Owing to the effects of intraindividual variation, estimating workers' exposures from a few measurements can attenuate measures of effect. To examine such effects on studies relating long-term exposure to a continuous health outcome, we evaluated the utility of each exposure measure by comparing the necessary sample sizes required for accurate estimation of a slope coefficient obtained from a regression analysis. No single measure outperformed the others for all groups of workers. However, when workers were evaluated together, creatinine-corrected urinary mercury better discriminated workers' exposures than airborne or blood mercury levels. Thus, pilot studies should be conducted to examine variability in both air and biomonitoring data because quantitative information about the relative magnitude of the intra- and interindividual sources of variation feeds directly into our efforts to design an optimal sampling strategy when evaluating health risks associated with occupational or environmental contaminants. Images Figure 1 PMID:10856033

  4. Radiation Pressure Measurements on Micron-Size Individual Dust Grains

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Witherow, W. K.; West, E. A.; Gallagher, D. L.; Adrian, M. L.; Fishman, G. J.; Tankosic, D.; LeClair, A.

    2003-01-01

    Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2- to 6.82-micron range and irradiating them from above with laser radiation focused to beam widths of approximately 175- 400 microns at ambient pressures particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of SiO2 and the corresponding extinction and scattering efficiencies.

  5. Neutron Measurements Using the Universal Radiation Spectrum Analyzer

    SciTech Connect

    Rick Cummings; Byron Christiansen; Laird Bean

    2005-02-01

    The Universal Radiation Spectrum Analyzer (URSA-II), developed by Radiation Safety Associates, and manufactured by SE International (Figure 1) is an interface between a radiation detector and a personal computer. Originally, the URSA-II was developed for use with detectors that measure the energy of gamma rays. At the Idaho National Laboratory, the URSA-II is an integral part of standard measurement techniques to measure characteristics of neutron radiation fields. Those techniques are discussed briefly and spectra using the URSA-II are presented.

  6. A first attempt to derive soil erosion rates from 137Cs airborne gamma measurements in two Alpine valleys

    NASA Astrophysics Data System (ADS)

    Arata, Laura; Meusburger, Katrin; Bucher, Benno; Mabit, Lionel; Alewell, Christine

    2016-04-01

    The application of fallout radionuclides (FRNs) as soil tracers is currently one of the most promising and effective approach for evaluating soil erosion magnitudes in mountainous grasslands. Conventional assessment or measurement methods are laborious and constrained by the topographic and climatic conditions of the Alps. The 137Cs (half-life = 30.2 years) is the most frequently used FRN to study soil redistribution. However the application of 137Cs in alpine grasslands is compromised by the high heterogeneity of the fallout due to the origin of 137Cs fallout in the Alps, which is linked to single rain events occurring just after the Chernobyl accident when most of the Alpine soils were still covered by snow. The aim of this study was to improve our understanding of the 137Cs distribution in two study areas in the Central Swiss Alps: the Ursern valley (Canton Uri), and the Piora valley (Canton Ticino). In June 2015, a helicopter equipped with a NaI gamma detector flew over the two study sites and screened the 137Cs activity of the top soil. The use of airborne gamma measurements is particularly efficient in case of higher 137Cs concentration in the soil. Due to their high altitude and high precipitation rates, the Swiss Alps are expected to be more contaminated by 137Cs fallout than other parts of Switzerland. The airborne gamma measurements have been related to several key parameters which characterize the areas, such as soil properties, slopes, expositions and land uses. The ground truthing of the airborne measurements (i.e. the 137Cs laboratory measurements of the soil samples collected at the same points) returned a good fit. The obtained results offer an overview of the 137Cs concentration in the study areas, which allowed us to identify suitable reference sites, and to analyse the relationship between the 137Cs distribution and the above cited parameters. The authors also derived a preliminary qualitative and a quantitative assessment of soil redistribution

  7. Pulsed airborne lidar measurements of atmospheric optical depth using the Oxygen A-band at 765 nm

    NASA Astrophysics Data System (ADS)

    Riris, H.; Rodriguez, M.; Allan, G. R.; Mao, J.; Hasselbrack, W.; Abshire, J. B.

    2013-12-01

    We report on an airborne demonstration of atmospheric oxygen (O2) optical depth measurements with an Integrated Path Differential Absorption (IPDA) lidar using a fiber-based laser system and a photon counting detector. Accurate atmospheric temperature and pressure measurements are required for NASA's Active Sensing of CO2 Emissions over Nights, Days and Seasons (ASCENDS) space mission. Since O2 in uniformly mixed in the atmosphere, its absorption spectra can be used to estimate atmospheric pressure. In its airborne configuration, the IPDA lidar uses a doubled Erbium Doped Fiber amplifier and single photon counting detector to measure oxygen absorption at multiple discrete wavelengths in the oxygen A-band near 765 nm. This instrument has been deployed three times aboard NASA's DC-8 airborne laboratory as part of campaigns to measure CO2 mixing ratios over a wide range of topography and weather conditions from altitudes between 3 km and 13 km. The O2 IPDA lidar flew seven flights in 2011 and six flights in 2013 in the continental United States and British Columbia, Canada. Our results from 2011 showed good agreement between the experimentally derived differential optical depth measurements with the theoretical predictions for aircraft altitudes from 3 to 13 km after a systematic bias correction of approximately 8% was applied. The random noise component was 2.5-3.0 %. The most recent data recorded in 2013 show better agreement between experimental optical depth measurements and theoretical predictions and much smaller systematic errors. The random error remained comparable with 2011 at 2-3%. The main source of random error is primarily the low energy (power) of the laser transmitter and the high solar background. We are in the process of addressing this issue with a new, higher energy amplifier that we anticipate will reduce the random noise component by a factor of 3-5 to less than 0.5%. The results from these flights show that the IPDA technique is a viable method

  8. Method for increased sensitivity of radiation detection and measurement

    DOEpatents

    Miller, Steven D.

    1994-01-01

    Dose of radiation to which a body of crystalline material has been exposed is measured by exposing the body to optical radiation at a first wavelength, which is greater than about 540 nm, and measuring optical energy emitted from the body by luminescence at a second wavelength, which is longer than the first wavelength. Reduced background is accomplished by more thorough annealing and enhanced radiation induced luminescence is obtained by treating the crystalline material to coalesce primary damage centers into secondary damage centers.

  9. Estimation of the Ozone Destruction in Clouds Derived from the Airborne Measurements

    NASA Astrophysics Data System (ADS)

    Belan, Boris; Arshinov, Mikhail; Fofonov, Aleksandr; Tolmachev, Gennadii

    2010-05-01

    Variations of tropospheric ozone concentration are studied based on the airborne sounding data. The chemiluminescent 3-02P (OPTEC, Russia) and two UV Model 49C (Thermo Electron Corp., USA) ozone analysers were used in these measurements simultaneously. Clouds of Cu, Cu med., St, Sc, As, and Ac types were studied. The thickness of cloud layers was 1.5 km on the average and varied from 0.4 to 4.5 km. The ozone destruction in clouds was 11-15 ppb on the average and within a range from 3 to 34 ppb. The destruction varied almost twofold depending on a cloud type. The decrease in the ozone concentration in Cu med. exceeds those in Ac clouds by 1.75 times. The widest variation range of ozone concentration is also in Cu med. The relative variation is maximum in As clouds, it reaches 27%. The minimum one (17%) has been recorded in Cu, St, and Ac clouds; this is seemingly caused by their water content. The given above data on variations of ozone concentration in clouds allow estimation to the first approximation of the ozone sink scales from the troposphere while interacting with cloud aerosols. The annual mean amount of clouds over the Earth is 5.8, i.e. 58% of the surface is covered by clouds. The Earth area is 5.1 ×1014 m2. During our experiments, we have obtained the thickness of cloud cover equal to 1.5 km; hence, the volume where the ozone sink occurs is 4.44×1017 m3. According to the data available, the variation of ozone concentration is 11 ppb by the 'minimum' and 15 ppb by the 'maximum' ozonometers, or 22 and 30 ?g/m3. Multiplying the volume by the concentration, obtain 97.6 and 133.1 Tg of ozone precipitating on aerosol particles in clouds. So obtained estimate is close to the values of annual tropospheric ozone budget and equal to 141 and 241 Tg per year. This work was funded by Presidium of RAS (Program No. 16), Brunch of Geology, Geophysics and Mining Sciences of RAS (Program No 5), Russian Foundation for Basic Research (grant No 08-05-92499), and Federal

  10. Spatial variability in near-surface chlorophyll a fluorescence measured by the Airborne Oceanographic Lidar (AOL)

    NASA Astrophysics Data System (ADS)

    Yoder, James A.; Aiken, James; Swift, Robert N.; Hoge, Frank E.; Stegmann, Petra M.

    The primary purpose of the aircraft remote sensing component of the North Atlantic Bloom Experiment (NABE) was to: (1) quantify spatial patterns of surface Chl a variability and co-variability with temperature ( T) within the NABE study regions along the 20°W meridian near 48 and 60°N; and (2) determine if the major NABE ship and mooring locations were representative of surrounding ocean waters with respect to large-scale distributions of surface Chl a and T. The sampling platform was a NASA P-3 aircraft equipped with the Airborne Oceanographic Lidar (AOL) system, which measures laser-induced Chl a fluorescence (LICF), upwelling spectral radiance and surface temperature ( T). Results collected during nine AOL missions conducted between 26 April and 3 June show considerable mesoscale variability in LICF and T. Spatial statistics (structure functions) showed that the dominant scales of LICF and T were significantly correlated in the range 10-290 km. Spectral analysis of the results of long flight lines showed spectral slopes averaging -2 for both LICF and T for spatial scales in the range 1.2-50 km. As for previous investigations of this type, we interpret the correlation between LICF and T as evidence that physical processes such as upwelling and mixing are dominant processes affecting spatial variations in Chl a distributions in the North Atlantic during the period of our sampling. The minimum dominant T and LICF spatial scales (ca 10 km) we determined from structure functions are similar to minimum scales predicted from models ( WOODS, 1988, In: Toward a theory on biological-physical interactions in the world ocean, Kluwer Academic, Boston, pp. 7-30) of upwelling induced by vortex contraction on the anticyclonic side of mesoscale jets. The NABE experiment was planned with the explicit assumption that major biological and chemical gradients are in the north-south direction in the northeast Atlantic. Our results support this assumption, and we observed no large

  11. 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

  12. Lidar measurements of ozone and aerosol distributions during the 1992 airborne Arctic stratospheric expedition

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Butler, Carolyn F.; Fenn, Marta A.; Grant, William B.; Ismail, Syed; Carter, Arlen F.

    1994-01-01

    The NASA Langley airborne differential absorption lidar system was operated from the NASA Ames DC-8 aircraft during the 1992 Airborne Arctic Stratospheric Expedition to investigate the distribution of stratospheric aerosols and ozone (O3) across the Arctic vortex from January to March 1992. Aerosols from the Mt. Pinatubo eruption were found outside and inside the Arctic vortex with distinctly different scattering characteristics and spatial distributions in the two regions. The aerosol and O3 distributions clearly identified the edge of the vortex and provided additional information on vortex dynamics and transport processes. Few polar stratospheric clouds were observed during the AASE-2; however, those that were found had enhanced scattering and depolarization over the background Pinatubo aerosols. The distribution of aerosols inside the vortex exhibited relatively minor changes during the AASE-2. Ozone depletion inside the vortex as limited to less than or equal to 20 percent in the altitude region from 15-20 km.

  13. The measurement and interpretation of Br/Pb ratios in airborne particles

    NASA Astrophysics Data System (ADS)

    Harrison, Roy M.; Sturges, W. T.

    Concentrations of bromide in atmospheric particles have commonly been used as an indicator of vehicle-emitted lead, since the two elements are associated in auto exhaust. A depression in the Br/Pb ratio from that in fresh auto exhaust has generally been interpreted in terms of an industrial contribution to airborne lead, despite the known loss of bromine from airborne particles during ageing processes in the atmosphere. In this article the available analytical techniques for determination of Br/Pb ratios are critically evaluated, and the reported values of Br/Pb ratios in ambient air are reviewed. The possible reasons for variability in Br/Pb ratios are discussed and recommendations made for the evaluation of Br/Pb ratio data.

  14. Sources of methane and nitrous oxide in California's Central Valley estimated through direct airborne flux and positive matrix factorization source apportionment of groundbased and regional tall tower measurements

    NASA Astrophysics Data System (ADS)

    Guha, Abhinav

    Methane (CH4) and nitrous oxide (N2O) are two major greenhouse gases that contribute significantly to the increase in anthropogenic radiative-forcing causing perturbations to the earth's climate system. In a watershed moment in the state's history of environmental leadership and commitment, California, in 2006, opted for sharp reductions in their greenhouse gas (GHG) emissions and adopted a long-term approach to address climate change that includes regulation of emissions from individual emitters and source categories. There are large CH4 and N2O emissions sources in the state, predominantly in the agricultural and waste management sector. While these two gases account for < 10% of total annual greenhouse gas emissions of the state, large uncertainties exist in their `bottom-up' accounting in the state GHG inventory. Additionally, an increasing number of `top-down' studies based on ambient observations point towards underestimation of their emissions in the inventory. Three intensive field observation campaigns that were spatially and temporally diverse took place between 2010 and 2013 in the Central Valley of California where the largest known sources of CH4 and N2O (e.g. agricultural systems and dairies) and potentially significant CH4 sources (e.g. oil and gas extraction) are located. The CalNex (California Nexus - Research at the Nexus of Air Quality and Climate Change) field campaign during summer 2010 (May 15 - June 30) took place in the urban core of Bakersfield in the southern San Joaquin Valley, a city whose economy is built around agriculture and the oil and gas industry. During summer of 2011, airborne measurements were performed over a large spatial domain, all across and around the Central Valley as part of the CABERNET (California Airborne BVOC Emission Research in Natural Ecosystem Transects) study. Next, a one-year continuous field campaign (WGC 2012-13, June 2012 - August 2013) was conducted at the Walnut Grove tall tower near the Sacramento

  15. International Symposium on Airborne Geophysics

    NASA Astrophysics Data System (ADS)

    Mogi, Toru; Ito, Hisatoshi; Kaieda, Hideshi; Kusunoki, Kenichiro; Saltus, Richard W.; Fitterman, David V.; Okuma, Shigeo; Nakatsuka, Tadashi

    2006-05-01

    Airborne geophysics can be defined as the measurement of Earth properties from sensors in the sky. The airborne measurement platform is usually a traditional fixed-wing airplane or helicopter, but could also include lighter-than-air craft, unmanned drones, or other specialty craft. The earliest history of airborne geophysics includes kite and hot-air balloon experiments. However, modern airborne geophysics dates from the mid-1940s when military submarine-hunting magnetometers were first used to map variations in the Earth's magnetic field. The current gamut of airborne geophysical techniques spans a broad range, including potential fields (both gravity and magnetics), electromagnetics (EM), radiometrics, spectral imaging, and thermal imaging.

  16. Pyroelectric detector development for the Radiation Measurement system

    NASA Technical Reports Server (NTRS)

    Hubbard, G. S.; Mcmurray, Robert E., Jr.; Hanel, R. P.; Dominguez, D. E.; Valero, F. P. J.; Baumann, Hilary; Hansen, W. L.; Haller, E. E.

    1993-01-01

    A new class of high detectivity pyroelectric detectors developed for optimization of the radiation measurement system within the framework of the Atmospheric Radiation Measurement program is described. These devices are intended to provide detectivities of up to about 10 exp 11 cm Hz exp 0.5/W with cooling to about 100 K required for the detector focal plane.

  17. Aerosol, Cloud and Trace Gas Observations Derived from Airborne Hyperspectral Radiance and Direct Beam Measurements in Recent Field Campaigns

    NASA Technical Reports Server (NTRS)

    Redemann, J.; Flynn, C. J.; Shinozuka, Y.; Kacenelenbogen, M.; Segal-Rosenheimer, M.; LeBlanc, S.; Russell, P. B.; Livingston, J. M.; Schmid, B.; Dunagan, S. E.; Johnson, R. R.

    2014-01-01

    The AERONET (AErosol RObotic NETwork) ground-based suite of sunphotometers provides measurements of spectral aerosol optical depth (AOD), precipitable water and spectral sky radiance, which can be inverted to retrieve aerosol microphysical properties that are critical to assessments of aerosol-climate interactions. Because of data quality criteria and sampling constraints, there are significant limitations to the temporal and spatial coverage of AERONET data and their representativeness for global aerosol conditions. The 4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research) instrument, jointly developed by NASA Ames and PNNL with NASA Goddard collaboration, combines airborne sun tracking and AERONET-like sky scanning with spectroscopic detection. Being an airborne instrument, 4STAR has the potential to fill gaps in the AERONET data set. Dunagan et al. [2013] present results establishing the performance of the instrument, along with calibration, engineering flight test, and preliminary scientific field data. The 4STAR instrument operated successfully in the SEAC4RS [Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys] experiment in Aug./Sep. 2013 aboard the NASA DC-8 and in the DoE [Department of Energy]-sponsored TCAP [Two Column Aerosol Project, July 2012 & Feb. 2013] experiment aboard the DoE G-1 aircraft (Shinozuka et al., 2013), and acquired a wealth of data in support of mission objectives on all SEAC4RS and TCAP research flights. 4STAR provided direct beam measurements of hyperspectral AOD, columnar trace gas retrievals (H2O, O3, NO2; Segal-Rosenheimer et al., 2014), and the first ever airborne hyperspectral sky radiance scans, which can be inverted to yield the same products as AERONET ground-based observations. In addition, 4STAR measured zenith radiances underneath cloud decks for retrievals of cloud optical depth and effective diameter. In this presentation, we provide an overview of the new

  18. Long-term Airborne Black Carbon Measurements on a Lufthansa Passenger Aircraft

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Su, H.; Ditas, J.; Scharffe, D.; Wang, S.; Zhang, Y.; McMeeking, G. R.; Brenninkmeijer, C. A. M.; Poeschl, U.

    2015-12-01

    Aerosol particles containing black carbon are the most absorbing component of incoming solar radiation and exert a significant positive radiative forcing thus forming next to CO2 the strongest component of current global warming. Nevertheless, the role of black carbon particles and especially their complex interaction with clouds needs further research which is hampered by the limited experimental data, especially observations in the free troposphere, and in the UTLS (upper troposphere and lower stratosphere). In August 2014, a single particle soot photometer (SP2) was included in the extensive scientific payload of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. CARIBIC is in operation since 1997 and carries out systematic observations of trace gas and aerosol sampling and on-line analyses, as well as DOAS remote sensing system at 10-12 km altitude. For this a special air freight container combining different instruments is transported on a monthly basis using a Lufthansa Airbus A340-600 passenger aircraft with destinations from 120°W to 120°E and 10°N to 75°N. The integration of a SP2 offers the possibility for the first long-term measurement of global distribution of black carbon. Up to date the SP2 measurements have been analyzed for 392 flights hours over four continents (Fig. 1). The first measurements show promising results of black carbon including periods when background concentrations in the UTLS were encountered. Beside a general distribution of number and mass of black carbon particles, peak events were detected with up to 20 times higher concentrations compared to the background. Moreover, high con