Science.gov

Sample records for airborne methane measurements

  1. 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.

  2. 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

  3. 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.

  4. 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.

  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. 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

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  15. 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.

  16. 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

  17. 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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  19. First Airborne IPDA Lidar Measurements of Methane and Carbon Dioxide Applying the DLR Greenhouse Gas Sounder CHARM-F

    NASA Astrophysics Data System (ADS)

    Amediek, A.; Ehret, G.; Fix, A.; Wirth, M.; Quatrevalet, M.; Büdenbender, C.; Kiemle, C.; Loehring, J.; Gerbig, C.

    2015-12-01

    First airborne measurement using CHARM-F, the four-wavelengths lidar for simultaneous soundings of atmospheric CO2 and CH4, were performed in Spring 2015 onboard the German research aircraft HALO. The lidar is designed in the IPDA (integrated path differential absorption) configuration using short double pulses, which gives column averaged gas mixing ratios between aircraft and ground. HALO's maximum flight altitude of 15 km and special features of the lidar, such as a relatively large laser ground spot, enable the CHARM-F system to be an airborne demonstrator for future spaceborne greenhouse gas lidars. Due to a high technological conformity this applies in particular to the French-German satellite mission MERLIN, the spaceborne methane IPDA lidar. The successfully completed flight measurements provide a valuable dataset, which supports the retrieval algorithm development for MERLIN notably. The flights covered different ground cover types, different orography types as well as the sea. Additionally, we captured different cloud conditions, at which the broken cloud case is a matter of particular interest. This dataset allows detailed analyses of measurement sensitivities, general studies on the IPDA principle and on technical details of the system. These activities are supported by another instrument onboard: 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 lidar. Additionally the onboard instrumentation of HALO gives information about pressure and temperature for cross-checking the ECMWF data, which are intended to be used for calculating the weighting function, the key quantity for the retrieval of gas column mixing ratios from the measured gas optical depths. In combination with dedicated descents into the boundary layer and subsequent ascents, a self-contained dataset for characterizations of CHARM-F is available.

  20. Airborne flux measurements of methane and volatile organic compounds over the Haynesville and Marcellus shale gas production regions

    NASA Astrophysics Data System (ADS)

    Yuan, Bin; Kaser, Lisa; Karl, Thomas; Graus, Martin; Peischl, Jeff; Campos, Teresa L.; Shertz, Steve; Apel, Eric C.; Hornbrook, Rebecca S.; Hills, Alan; Gilman, Jessica B.; Lerner, Brian M.; Warneke, Carsten; Flocke, Frank M.; Ryerson, Thomas B.; Guenther, Alex B.; Gouw, Joost A.

    2015-06-01

    Emissions of methane (CH4) and volatile organic compounds (VOCs) from oil and gas production may have large impacts on air quality and climate change. Methane and VOCs were measured over the Haynesville and Marcellus shale gas plays on board the National Center for Atmospheric Research C-130 and NOAA WP-3D research aircraft in June-July of 2013. We used an eddy covariance technique to measure in situ fluxes of CH4 and benzene from both C-130 flights with high-resolution data (10 Hz) and WP-3D flights with low-resolution data (1 Hz). Correlation (R = 0.65) between CH4 and benzene fluxes was observed when flying over shale gas operations, and the enhancement ratio of fluxes was consistent with the corresponding concentration observations. Fluxes calculated by the eddy covariance method show agreement with a mass balance approach within their combined uncertainties. In general, CH4 fluxes in the shale gas regions follow a lognormal distribution, with some deviations for relatively large fluxes (>10 µg m-2 s-1). Statistical analysis of the fluxes shows that a small number of facilities (i.e., ~10%) are responsible for up to ~40% of the total CH4 emissions in the two regions. We show that the airborne eddy covariance method can also be applied in some circumstances when meteorological conditions do not favor application of the mass balance method. We suggest that the airborne eddy covariance method is a reliable alternative and complementary analysis method to estimate emissions from oil and gas extraction.

  1. 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

    indicate the system capability of measuring CH4 concentration with <0.5% total error up to 3.25 km range with 5 minute averaging from ground. For airborne IPDA, the precision in the column dry mixing ratio is approximately 0.2% with 0.1 sec averaging using land surface returns. The simulated CH4 DIAL has a unique capability of combining signals from atmospheric scattering (aerosols and molecular) from layers above the surface with return signals from the surface, which provides methane column measurement between the atmospheric scattering layer and the surface, therefore allowing for delineation of the boundary layer influence from the total column CH4. In such case 0.5% and 1.2% total errors are achieved with 10 sec average from airborne platforms at 8 km and 15.24 km altitudes, respectively. Such a DIAL system would be ideal for investigating anthropogenic emissions from natural gas extraction sites as well as CH4 releases over polar ice sheets, permafrost regions, wetlands, and over oceans during day and night.

  2. Analyzing Source Apportioned Methane in Northern California During DISCOVER-AQ-CA Using Airborne Measurements and Model Simulations

    NASA Technical Reports Server (NTRS)

    Johnson, Matthew S.

    2014-01-01

    This study analyzes source apportioned methane (CH4) emissions and atmospheric concentrations in northern California during the Discover-AQ-CA field campaign using airborne measurement data and model simulations. Source apportioned CH4 emissions from the Emissions Database for Global Atmospheric Research (EDGAR) version 4.2 were applied in the 3-D chemical transport model GEOS-Chem and analyzed using airborne measurements taken as part of the Alpha Jet Atmospheric eXperiment over the San Francisco Bay Area (SFBA) and northern San Joaquin Valley (SJV). During the time period of the Discover-AQ-CA field campaign EDGAR inventory CH4 emissions were 5.30 Gg/day (Gg 1.0 109 grams) (equating to 1.9 103 Gg/yr) for all of California. According to EDGAR, the SFBA and northern SJV region contributes 30 of total emissions from California. Source apportionment analysis during this study shows that CH4 concentrations over this area of northern California are largely influenced by global emissions from wetlands and local/global emissions from gas and oil production and distribution, waste treatment processes, and livestock management. Model simulations, using EDGAR emissions, suggest that the model under-estimates CH4 concentrations in northern California (average normalized mean bias (NMB) -5 and linear regression slope 0.25). The largest negative biases in the model were calculated on days when hot spots of local emission sources were measured and atmospheric CH4 concentrations reached values 3.0 parts per million (model NMB -10). Sensitivity emission studies conducted during this research suggest that local emissions of CH4 from livestock management processes are likely the primary source of the negative model bias. These results indicate that a variety, and larger quantity, of measurement data needs to be obtained and additional research is necessary to better quantify source apportioned CH4 emissions in California and further the understanding of the physical processes

  3. Analyzing source apportioned methane in northern California during Discover-AQ-CA using airborne measurements and model simulations

    SciTech Connect

    Johnson, Matthew S.; Yates, Emma L.; Iraci, Laura T.; Loewenstein, Max; Tadić, Jovan M.; Wecht, Kevin J.; Jeong, Seongeun; Fischer, Marc L.

    2014-12-01

    This study analyzes source apportioned methane (CH4) emissions and atmospheric mixing ratios in northern California during the Discover-AQ-CA field campaign using airborne measurement data and model simulations. Source apportioned CH4 emissions from the Emissions Database for Global Atmospheric Research (EDGAR) version 4.2 were applied in the 3-D chemical transport model GEOS-Chem and analyzed using airborne measurements taken as part of the Alpha Jet Atmospheric eXperiment over the San Francisco Bay Area (SFBA) and northern San Joaquin Valley (SJV). During the time period of the Discover-AQ-CA field campaign EDGAR inventory CH4 emissions were ~5.30 Gg day –1 (Gg = 1.0 × 109 g) (equating to ~1.90 × 103 Gg yr–1) for all of California. According to EDGAR, the SFBA and northern SJV region contributes ~30% of total CH4 emissions from California. Source apportionment analysis during this study shows that CH4 mixing ratios over this area of northern California are largely influenced by global emissions from wetlands and local/global emissions from gas and oil production and distribution, waste treatment processes, and livestock management. Model simulations, using EDGAR emissions, suggest that the model under-estimates CH4 mixing ratios in northern California (average normalized mean bias (NMB) = –5.2% and linear regression slope = 0.20). The largest negative biases in the model were calculated on days when large amounts of CH4 were measured over local emission sources and atmospheric CH4 mixing ratios reached values >2.5 parts per million. Sensitivity emission studies conducted during this research suggest that local emissions of CH4 from livestock management processes are likely the primary source of the negative model bias. These results indicate that a variety, and larger quantity, of measurement data needs to be

  4. Analyzing source apportioned methane in northern California during Discover-AQ-CA using airborne measurements and model simulations

    DOE PAGES

    Johnson, Matthew S.; Yates, Emma L.; Iraci, Laura T.; ...

    2014-12-01

    This study analyzes source apportioned methane (CH4) emissions and atmospheric mixing ratios in northern California during the Discover-AQ-CA field campaign using airborne measurement data and model simulations. Source apportioned CH4 emissions from the Emissions Database for Global Atmospheric Research (EDGAR) version 4.2 were applied in the 3-D chemical transport model GEOS-Chem and analyzed using airborne measurements taken as part of the Alpha Jet Atmospheric eXperiment over the San Francisco Bay Area (SFBA) and northern San Joaquin Valley (SJV). During the time period of the Discover-AQ-CA field campaign EDGAR inventory CH4 emissions were ~5.30 Gg day –1 (Gg = 1.0 ×more » 109 g) (equating to ~1.90 × 103 Gg yr–1) for all of California. According to EDGAR, the SFBA and northern SJV region contributes ~30% of total CH4 emissions from California. Source apportionment analysis during this study shows that CH4 mixing ratios over this area of northern California are largely influenced by global emissions from wetlands and local/global emissions from gas and oil production and distribution, waste treatment processes, and livestock management. Model simulations, using EDGAR emissions, suggest that the model under-estimates CH4 mixing ratios in northern California (average normalized mean bias (NMB) = –5.2% and linear regression slope = 0.20). The largest negative biases in the model were calculated on days when large amounts of CH4 were measured over local emission sources and atmospheric CH4 mixing ratios reached values >2.5 parts per million. Sensitivity emission studies conducted during this research suggest that local emissions of CH4 from livestock management processes are likely the primary source of the negative model bias. These results indicate that a variety, and larger quantity, of measurement data needs to be obtained and additional research is necessary to better quantify source apportioned CH4 emissions in California.« less

  5. Investigating Seasonal Emissions of Carbon Dioxide and Methane in Northern California Using Airborne Measurements and Inverse Modeling

    NASA Astrophysics Data System (ADS)

    Johnson, M. S.; Xi, X.; Yates, E. L.; Iraci, L. T.; Potter, C. S.; Tanaka, T.; Tadic, J.; Loewenstein, M.; Jeong, S.; Fischer, M. L.; Gurney, K. R.

    2014-12-01

    Greenhouse gas (GHG) concentrations have increased over the past decades and are linked to increasing global surface temperatures and climate change. To counteract the trend of increasing atmospheric concentrations of GHGs, the state of California has passed the California Global Warming Solutions Act of 2006 (AB-32). This requires that by 2020, GHG (e.g., carbon dioxide (CO2) and methane (CH4)) emissions will be reduced to 1990 levels. Currently, California emits ~500 Tg yr-1 of CO2eq GHGs, with CO2 and CH4 contributing ~90% of the total. To quantify the success of AB-32, GHG emission rates must be more thoroughly quantified in California. Presently, uncertainties remain in the existing "bottom-up" emission inventories in California due to many contributing factors not being fully understood. To help alleviate these uncertainties, we have analyzed airborne GHG measurements and applied inverse modeling techniques to quantify GHG spatiotemporal concentration patterns and "top-down" emission rates. To assess the magnitude/spatial variation of GHGs, and to identify local emission "hot spots", airborne measurements of CO2 and CH4 were made by the Alpha Jet Atmospheric eXperiment (AJAX) in the boundary layer of the San Francisco Bay Area (SFBA) and northern San Joaquin Valley (SJV) in Jan.-Feb. 2013 and July-Aug. 2014. To quantify/constrain GHG emissions we applied the WRF-STILT model and inverse modeling techniques, in conjunction with AJAX data, to estimate "top-down" SFBA/SJV GHG emission rates. Model simulations utilized source apportioned a priori CO2 and CH4 emission inventories from the Vulcan Project (including NASA Carnegie Ames Stanford Approach (NASA-CASA) model CO2 biosphere fluxes) and the California Greenhouse Gas Emissions Measurement (CALGEM) Project, respectively. Results from the evaluation of a priori and posterior GHG concentrations/emissions in northern California using AJAX data, along with the analysis of CO2 and CH4 concentration spatiotemporal

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  7. Airborne FTIR remote sensing of methane from the FAAM aircraft

    NASA Astrophysics Data System (ADS)

    Allen, Grant; Illingworth, Samuel; Mead, Iq; Harlow, Chawn; Newman, Stuart; Vance, Alan

    2015-04-01

    This paper presents the first campaign results for retrievals of methane (and other gases and thermodynamic parameters) from the Airborne Research Interferometer Evaluation System (ARIES) FTIR instrument on the UK Facility for Airborne Atmospheric Measurement (FAAM) BAE-146 aircraft. The ARIES is a thermal infrared BOMEM FTS tailored for airborne use and has an unapodised spectral resolution of 1 cm-1. It was developed as an IASI analogue for radiometric calibration of its satellite countepart. We will discuss the technical and theoretical assessment of the ARIES retrieval processor and present retrievals and interpretation of remote sampling over several years of campaign data in the tropics, around the UK, and in the high Arctic, during the Jaivex, GAUGE and MAMM campaigns respectively. Validation studies against airborne in situ data have shown that ARIES can achieve accuracties of ~2% in partial column retrievals of methane, while providing simultaneous information on a wide range of other trace gases typical of FTIR measurement. The ARIES has now beein in operation on the FAAM aircraft for a range of campaigns around the world and represents a useful validation bridge between high precision in situ point measurements (on the ground and by aircraft) and satellite remote sensing.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  9. 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

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

    PubMed

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

    2014-11-25

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

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

    PubMed Central

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

    2014-01-01

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

  12. Airborne Ethane Observations in the Barnett Shale: Quantification of Ethane Flux and Attribution of Methane Emissions.

    PubMed

    Smith, Mackenzie L; Kort, Eric A; Karion, Anna; Sweeney, Colm; Herndon, Scott C; Yacovitch, Tara I

    2015-07-07

    We present high time resolution airborne ethane (C2H6) and methane (CH4) measurements made in March and October 2013 as part of the Barnett Coordinated Campaign over the Barnett Shale formation in Texas. Ethane fluxes are quantified using a downwind flight strategy, a first demonstration of this approach for C2H6. Additionally, ethane-to-methane emissions ratios (C2H6:CH4) of point sources were observationally determined from simultaneous airborne C2H6 and CH4 measurements during a survey flight over the source region. Distinct C2H6:CH4 × 100% molar ratios of 0.0%, 1.8%, and 9.6%, indicative of microbial, low-C2H6 fossil, and high-C2H6 fossil sources, respectively, emerged in observations over the emissions source region of the Barnett Shale. Ethane-to-methane correlations were used in conjunction with C2H6 and CH4 fluxes to quantify the fraction of CH4 emissions derived from fossil and microbial sources. On the basis of two analyses, we find 71-85% of the observed methane emissions quantified in the Barnett Shale are derived from fossil sources. The average ethane flux observed from the studied region of the Barnett Shale was 6.6 ± 0.2 × 10(3) kg hr(-1) and consistent across six days in spring and fall of 2013.

  13. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    SciTech Connect

    Jerry Myers

    2003-11-12

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. This second six-month technical report summarizes the progress made towards defining, designing, and developing the hardware and software segments of the airborne, optical remote methane and ethane sensor. The most challenging task to date has been to identify a vendor capable of designing and developing a light source with the appropriate output wavelength and power. This report will document the work that has been done to identify design requirements, and potential vendors for the light source. Significant progress has also been made in characterizing the amount of light return available from a remote target at various distances from the light source. A great deal of time has been spent conducting laboratory and long-optical path target reflectance measurements. This is important since it helps to establish the overall optical output requirements for the sensor. It also reduces the relative uncertainty and risk associated with developing a custom light source. The data gathered from the optical path testing has been translated to the airborne transceiver design in such areas as: fiber coupling, optical detector selection, gas filters, and software analysis. Ophir will next, summarize the design progress of the transceiver hardware and software development. Finally, Ophir will discuss remaining project issues that may impact the success of the project.

  14. AIRBORNE, OPTICAL REMOTE SENSNG OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    SciTech Connect

    Jerry Myers

    2005-04-15

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. The scope of the work involved designing and developing an airborne, optical remote sensor capable of sensing methane and, if possible, ethane for the detection of natural gas pipeline leaks. Flight testing using a custom dual wavelength, high power fiber amplifier was initiated in February 2005. Ophir successfully demonstrated the airborne system, showing that it was capable of discerning small amounts of methane from a simulated pipeline leak. Leak rates as low as 150 standard cubic feet per hour (scf/h) were detected by the airborne sensor.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  16. Optical Parametric Technology for Methane Measurements

    NASA Technical Reports Server (NTRS)

    Dawsey, Martha; Numata, Kenji; Wu, Stewart; Riris, Haris

    2015-01-01

    Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas, with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. Yet, lack of understanding of the processes that control CH4 sources and sinks and its potential release from stored carbon reservoirs contributes significant uncertainty to our knowledge of the interaction between carbon cycle and climate change. At Goddard Space Flight Center (GSFC) we have been developing the technology needed to remotely measure CH4 from orbit. Our concept for a CH4 lidar is a nadir viewing instrument that uses the strong laser echoes from the Earth's surface to measure CH4. The instrument uses a tunable, narrow-frequency light source and photon-sensitive detector to make continuous measurements from orbit, in sunlight and darkness, at all latitudes and can be relatively immune to errors introduced by scattering from clouds and aerosols. Our measurement technique uses Integrated Path Differential Absorption (IPDA), which measures the absorption of laser pulses by a trace gas when tuned to a wavelength coincident with an absorption line. We have already demonstrated ground-based and airborne CH4 detection using Optical Parametric Amplifiers (OPA) at 1651 nm using a laser with approximately 10 microJ/pulse at 5kHz with a narrow linewidth. Next, we will upgrade our OPO system to add several more wavelengths in preparation for our September 2015 airborne campaign, and expect that these upgrades will enable CH4 measurements with 1% precision (10-20 ppb).

  17. Optical parametric technology for methane measurements

    NASA Astrophysics Data System (ADS)

    Dawsey, Martha; Numata, Kenji; Wu, Stewart; Riris, Haris

    2015-09-01

    Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas, with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. Yet, lack of understanding of the processes that control CH4 sources and sinks and its potential release from stored carbon reservoirs contributes significant uncertainty to our knowledge of the interaction between carbon cycle and climate change. At Goddard Space Flight Center (GSFC) we have been developing the technology needed to remotely measure CH4 from orbit. Our concept for a CH4 lidar is a nadir viewing instrument that uses the strong laser echoes from the Earth's surface to measure CH4. The instrument uses a tunable, narrow-frequency light source and photon-sensitive detector to make continuous measurements from orbit, in sunlight and darkness, at all latitudes and can be relatively immune to errors introduced by scattering from clouds and aerosols. Our measurement technique uses Integrated Path Differential Absorption (IPDA), which measures the absorption of laser pulses by a trace gas when tuned to a wavelength coincident with an absorption line. We have already demonstrated ground-based and airborne CH4 detection using Optical Parametric Amplifiers (OPA) at 1651 nm using a laser with approximately 10 μJ/pulse at 5kHz with a narrow linewidth. Next, we will upgrade our OPO system to add several more wavelengths in preparation for our September 2015 airborne campaign, and expect that these upgrades will enable CH4 measurements with 1% precision (10-20 ppb).

  18. Measuring Methane Production from Ruminants.

    PubMed

    Hill, Julian; McSweeney, Chris; Wright, André-Denis G; Bishop-Hurley, Greg; Kalantar-Zadeh, Kourosh

    2016-01-01

    Radiative forcing of methane (CH4) is significantly higher than carbon dioxide (CO2) and its enteric production by ruminant livestock is one of the major sources of greenhouse gas emissions. CH4 is also an important marker of farming productivity, because it is associated with the conversion of feed to product in livestock. Consequently, measurement of enteric CH4 is emerging as an important research topic. In this review, we briefly describe the conversion of carbohydrate to CH4 by the bacterial community within gut, and highlight some of the key host-microbiome interactions. We then provide a picture of current progress in techniques for measuring enteric CH4, the context in which these technologies are used, and the challenges faced. We also discuss solutions to existing problems and new approaches currently in development.

  19. A Novel Airborne Carbon Isotope Analyzer for Methane and Carbon Dioxide Source Fingerprinting

    NASA Astrophysics Data System (ADS)

    Berman, E. S.; Huang, Y. W.; Owano, T. G.; Leifer, I.

    2014-12-01

    Recent field studies on major sources of the important greenhouse gas methane (CH4) indicate significant underestimation of methane release from fossil fuel industrial (FFI) and animal husbandry sources, among others. In addition, uncertainties still exist with respect to carbon dioxide (CO2) measurements, especially source fingerprinting. CO2 isotopic analysis provides a valuable in situ measurement approach to fingerprint CH4 and CO2as associated with combustion sources, leakage from geologic reservoirs, or biogenic sources. As a result, these measurements can characterize strong combustion source plumes, such as power plant emissions, and discriminate these emissions from other sources. As part of the COMEX (CO2 and MEthane eXperiment) campaign, a novel CO2 isotopic analyzer was installed and collected data aboard the CIRPAS Twin Otter aircraft. Developing methods to derive CH4 and CO2 budgets from remote sensing data is the goal of the summer 2014 COMEX campaign, which combines hyperspectral imaging (HSI) and non-imaging spectroscopy (NIS) with in situ airborne and surface data. COMEX leverages the synergy between high spatial resolution HSI and moderate spatial resolution NIS. The carbon dioxide isotope analyzer developed by Los Gatos Research (LGR) uses LGR's patented Off-Axis ICOS (Integrated Cavity Output Spectroscopy) technology and incorporates proprietary internal thermal control for high sensitivity and optimal instrument stability. This analyzer measures CO2 concentration as well as δ13C, δ18O, and δ17O from CO2 at natural abundance (100-3000 ppm). The laboratory accuracy is ±1.2 ppm (1σ) in CO2 from 370-1000 ppm, with a long-term (1000 s) precision of ±0.012 ppm. The long-term precision for both δ13C and δ18O is 0.04 ‰, and for δ17O is 0.06 ‰. The analyzer was field-tested as part of the COWGAS campaign, a pre-cursor campaign to COMEX in March 2014, where it successfully discriminated plumes related to combustion processes associated with

  20. Quantification of methane emission rates from coal mine ventilation shafts using airborne remote sensing data

    NASA Astrophysics Data System (ADS)

    Krings, T.; Gerilowski, K.; Buchwitz, M.; Hartmann, J.; Sachs, T.; Erzinger, J.; Burrows, J. P.; Bovensmann, H.

    2013-01-01

    The quantification of emissions of the greenhouse gas methane is essential for attributing the roles of anthropogenic activity and natural phenomena in global climate change. Our current measurement systems and networks, whilst having improved during the last decades, are deficient in many respects. For example, the emissions from localised and point sources such as landfills or fossil fuel exploration sites are not readily assessed. A tool developed to better understand point sources of the greenhouse gases carbon dioxide and methane is the optical remote sensing instrument MAMAP (Methane airborne MAPper), operated from aircraft. After a recent instrument modification, retrievals of the column-averaged dry air mole fractions for methane XCH4 (or for carbon dioxide XCO2) derived from MAMAP data have a precision of about 0.4% or better and thus can be used to infer emission rate estimates using an optimal estimation inverse Gaussian plume model or a simple integral approach. CH4 emissions from two coal mine ventilation shafts in western Germany surveyed during the AIRMETH 2011 measurement campaign are used as examples to demonstrate and assess the value of MAMAP data for quantifying CH4 from point sources. While the knowledge of the wind is an important input parameter in the retrieval of emissions from point sources and is generally extracted from models, additional information from a turbulence probe operated on-board the same aircraft was utilised to enhance the quality of the emission estimates. Although flight patterns were optimised for remote sensing measurements, data from an in situ analyser for CH4 were found to be in good agreement with retrieved dry columns of CH4 from MAMAP and could be used to investigate and refine underlying assumptions for the inversion procedures. With respect to the total emissions of the mine at the time of the overflight, the inferred emission rate of 50.4 kt CH4 yr-1 has a difference of less than 1% compared to officially

  1. Regional measurements of methane fluxes and methane isotopologues in the North Slope of Alaska

    NASA Astrophysics Data System (ADS)

    Sayres, D. S.; Healy, C. E.; Munster, J.; Anderson, J. G.; Dumas, E.; Dobosy, R.; Baker, B.; Langford, J.

    2013-12-01

    Rapid changes in the Arctic climate, exemplified by the decrease in end of summer sea ice, require regional understanding of changes in the Arctic system. Due to the inaccessibility of much of the Arctic region in situ aircraft measurements are well suited to providing a high spatial resolution map of a changing Arctic. We present here measurements of methane emissions from thermokarst lakes and melting permafrost in the North Slope region of Alaska. These measurements were acquired during the summer 2013 mission of the Flux Observations of Carbon from an Airborne Laboratory (FOCAL) instrument suite using the Aurora Flight Sciences' Centaur aircraft. The FOCAL payload combines the Anderson Group's (Harvard University) Carbon spectrometers for measuring the concentrations of methane, carbon dioxide, nitrous oxide, and water vapor and the carbon isotopologues of methane and carbon dioxide with the NOAA Atmospheric Turbulence and Diffusion Division (ATDD) Best Air Turbulence (BAT) probe for measuring the turbulent winds from a moving aircraft. Together these allow for the measurement of trace gas fluxes. The measurements were obtained by flying low (~10 m altitude) over the North Slope.

  2. Lidar Measurements of Methane and Applications for Aircraft and Spacecraft

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Numata, Kenji; Abshire, James; Li, Steve; Wu, Stewart; Krainak, Michael; Sun, Xiaoli

    2010-01-01

    Atmospheric methane levels have remained relatively constant over the last decade around 1.78 parts per million (ppm) but observations since 2007 show that levels may be increasing. This trend may be caused by increased fossil fuel production, rice farming, livestock and landfills, but the underlying causes are quite uncertain. One hypothesis is that reservoirs of carbon trapped in the permafrost regions of northern Canada, Europe, and Siberia thaw as global temperatures rise and are releasing increasing amounts of methane. Another hypothesis points to increased production of methane by microbes as the permafrost warms. Currently most observations of greenhouse gases are limited to in-situ (surface and tower sites) and limited airborne in-situ measurements. Space column density measurements are starting to become available from the GOSAT mission. Although methane survives for a shorter time in the atmosphere than CO2, its impact on climate change per molecule is about 23 times than that of CO2. Accurate global observations of several greenhouse gases, including methane, are urgently needed in order to better understand climate change processes and to reduce the uncertainty in the carbon budget. Differential absorption lidar is a well-established technique to measure atmospheric gases, and methane has optical absorption bands near 1.65,2.2,3.4 and 7.8 micron. The near infrared overtones lines of CH4 near 1650 nm are relatively free of interference from other species. There are absorption lines near 1651 nm which are both temperature insensitive and have line strengths well suited for lidar measurements. We have developed a laser and demonstrated lidar measurements of CH4 using lines in this band. Our laser uses a narrow linewidth 1064 nm laser pulse passing through a nonlinear crystal. We generate the tunable laser signals near 1651 nm by using the optical parametric amplification (OPA) process. Inside the crystal the 1064 nm beam overlaps with an injection seed

  3. 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.

  4. 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).

  5. 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).

  6. Pasture-scale measurement of methane emissions of grazing cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantifying methane emission of cattle grazing on southern Great Plains pastures using micrometeorology presents several challenges. Cattle are elevated, mobile point sources of methane, so that knowing their location in relation to atmospheric methane concentration measurements becomes critical. St...

  7. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPLINE LEAK DETECTION

    SciTech Connect

    Jerry Myers

    2004-05-12

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. The third six-month technical report contains a summary of the progress made towards finalizing the design and assembling the airborne, remote methane and ethane sensor. The vendor has been chosen and is on contract to develop the light source with the appropriate linewidth and spectral shape to best utilize the Ophir gas correlation software. Ophir has expanded upon the target reflectance testing begun in the previous performance period by replacing the experimental receiving optics with the proposed airborne large aperture telescope, which is theoretically capable of capturing many times more signal return. The data gathered from these tests has shown the importance of optimizing the fiber optic receiving fiber to the receiving optic and has helped Ophir to optimize the design of the gas cells and narrowband optical filters. Finally, Ophir will discuss remaining project issues that may impact the success of the project.

  8. 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.

  9. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    SciTech Connect

    Jerry Myers

    2003-05-13

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. This six-month technical report summarizes the progress for each of the proposed tasks, discusses project concerns, and outlines near-term goals. Ophir has completed a data survey of two major natural gas pipeline companies on the design requirements for an airborne, optical remote sensor. The results of this survey are disclosed in this report. A substantial amount of time was spent on modeling the expected optical signal at the receiver at different absorption wavelengths, and determining the impact of noise sources such as solar background, signal shot noise, and electronic noise on methane and ethane gas detection. Based upon the signal to noise modeling and industry input, Ophir finalized the design requirements for the airborne sensor, and released the critical sensor light source design requirements to qualified vendors. Responses from the vendors indicated that the light source was not commercially available, and will require a research and development effort to produce. Three vendors have responded positively with proposed design solutions. Ophir has decided to conduct short path optical laboratory experiments to verify the existence of methane and absorption at the specified wavelength, prior to proceeding with the light source selection. Techniques to eliminate common mode noise were also evaluated during the laboratory tests. Finally, Ophir has included a summary of the potential concerns for project success and has established future goals.

  10. Directly attributing methane emissions to point source locations using the next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG)

    NASA Astrophysics Data System (ADS)

    Thorpe, A. K.; Thompson, D. R.; Frankenberg, C.; Aubrey, A. D.; Bue, B. D.; Green, R. O.; Kort, E. A.; Eastwood, M. L.; Helmlinger, M. C.; Nolte, S. H.

    2015-12-01

    Imaging spectrometers like the next generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) are well suited for identifying methane point sources by covering large regions with the high spatial resolution necessary to resolve emissions. A controlled release experiment at the Rocky Mountain Oilfield Testing Center (RMOTC) showed detectable methane plumes at multiple flux rates and flight altitudes. Images of plumes agreed with wind direction measured at ground stations and were consistently present for fluxes as low as 0.09 kt/year (14.16 cubic meters per hour; 500 standard cubic feet per hour, scfh). In some cases plumes were detected as low as 0.02 kt/year (3.40 cubic meters per hour; 120 scfh), indicating that AVIRIS-NG has the capability of detecting a number of fugitive methane source categories for natural gas fields. Following the RMOTC campaign, real time detection and geolocation of methane plumes has been implemented using an operator interface that overlays plumes on a true color image acquired by AVIRIS-NG. This has facilitated surveys over existing oil and gas fields to identify and attribute methane emissions to individual point source locations, including well pads known to use hydraulic fracturing and natural gas pipelines. An imaging spectrometer built exclusively for detection, quantification, and attribution of methane plumes would have improved sensitivity compared to AVIRIS-NG. The Airborne Methane Plume Spectrometer (AMPS) instrument concept is mature, ready for development, and would provide a spectral resolution of 1 nm and a detection threshold of approximately 0.28 cubic meters per hour (10 scfh). By offering the potential to identify point source locations, airborne imaging spectrometers could have particular utility for resolving the large uncertainties associated with anthropogenic emissions, including industrial point source emissions and fugitive methane from the oil and gas industry. Fig.1: True color image subset with

  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. Geogenic Sources Strongly Contribute to the Mackenzie River Delta's Methane Emissions Derived From Airborne Flux Data

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Arctic permafrost-associated wetlands and thawing permafrost emit the greenhouse gas methane (CH4), either as a product of recent microbial activity in the active layer or taliks, or from deeper geogenic sources where pathways through the permafrost exist. Current emission estimates vary strongly between different models and there is still disagreement between bottom-up estimates from local field studies and top-down estimates from atmospheric measurements. We use airborne flux data from two campaigns in the Mackenzie River Delta, Canada, in July 2012 and 2013 to directly quantify permafrost CH4 emissions on the regional scale, to analyse the regional pattern of CH4 fluxes and to estimate the contribution of geogenic emissions to the overall CH4 budget of the delta. CH4 fluxes were calculated with a time-frequency resolved version of the eddy covariance technique, resulting in a gridded 100 m x 100 m resolution flux map within the footprints of the flight tracks. We distinguish geogenic gas seeps from biogenic sources by their strength and show that they contribute strongly to the annual CH4 budget of the delta. Our study provides the first estimate of annual CH4 release from the Mackenzie River Delta and the adjacent coastal plain. We show that one percent of the covered area contains the strongest geogenic seeps which contribute disproportionately to the annual emission estimate. Our results show that geogenic CH4 emissions might need more attention, especially in areas where permafrost is vulnerable to thawing sufficiently to create pathways for geogenic gas migration. The presented map can be used as a baseline for future CH4 flux studies in the Mackenzie River Delta.

  13. Absolute Measurements of Methane on Mars

    NASA Astrophysics Data System (ADS)

    Mumma, M. J.; Villanueva, G. L.; Novak, R. E.

    2009-12-01

    spectral lines of methane, 2) Evidence for spatial variations that imply active release in discrete regions, and 3) Evidence for seasonal variations that imply a CH4 lifetime of months rather than the 300-plus years implied by photochemistry. The short lifetime may be the result of reaction with strong oxidants such as peroxides located in the soil and/or on airborne dust grains [1,6,8]. The possible origins of Mars methane will be discussed in the context of geologic and biologic terrestrial analogues. Very recent results will be presented. Acknowledgments: NASA's Planetary Astronomy Program (344-32-51-96) and Astrobiology Program (344-53-51); NSF RUI Grant AST-805540. References: [1] Mumma et al. (2009) Science 323, 1041-1045. [2] Formisano et al. (2004) Science 306, 1758-1761. [3] Krasnopolsky et al. (2004) Icarus 172, 537-547. [4] Geminale et al. (2008), Planet. Sp. Sci. 56,1194-1203. [5] Villanueva et al. (2009), submitted. [6] LeFevre and Forget (2009), Nature 460,720-723. [7] Novak et al. 2009, Mars III Workshop. [8] Atreya et al. (2007), Planet. Sp. Sci. 55,358-369.

  14. 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.

  15. Ground based mobile isotopic methane measurements in the Front Range, Colorado

    NASA Astrophysics Data System (ADS)

    Vaughn, B. H.; Rella, C.; Petron, G.; Sherwood, O.; Mielke-Maday, I.; Schwietzke, S.

    2014-12-01

    Increased development of unconventional oil and gas resources in North America has given rise to attempts to monitor and quantify fugitive emissions of methane from the industry. Emission estimates of methane from oil and gas basins can vary significantly from one study to another as well as from EPA or State estimates. New efforts are aimed at reconciling bottom-up, or inventory-based, emission estimates of methane with top-down estimates based on atmospheric measurements from aircraft, towers, mobile ground-based vehicles, and atmospheric models. Attributing airborne measurements of regional methane fluxes to specific sources is informed by ground-based measurements of methane. Stable isotopic measurements (δ13C) of methane help distinguish between emissions from the O&G industry, Confined Animal Feed Operations (CAFO), and landfills, but analytical challenges typically limit meaningful isotopic measurements to individual point sampling. We are developing a toolbox to use δ13CH4 measurements to assess the partitioning of methane emissions for regions with multiple methane sources. The method was applied to the Denver-Julesberg Basin. Here we present data from continuous isotopic measurements obtained over a wide geographic area by using MegaCore, a 1500 ft. tube that is constantly filled with sample air while driving, then subsequently analyzed at slower rates using cavity ring down spectroscopy (CRDS). Pressure, flow and calibration are tightly controlled allowing precise attribution of methane enhancements to their point of collection. Comparisons with point measurements are needed to confirm regional values and further constrain flux estimates and models. This effort was made in conjunction with several major field campaigns in the Colorado Front Range in July-August 2014, including FRAPPÉ (Front Range Air Pollution and Photochemistry Experiment), DISCOVER-AQ, and the Air Water Gas NSF Sustainability Research Network at the University of Colorado.

  16. 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

  17. Analyzers Measure Greenhouse Gases, Airborne Pollutants

    NASA Technical Reports Server (NTRS)

    2012-01-01

    to fuel cellular functions. "We think this chemical process did not exist when life first formed on Earth," he says, "because it is based on oxygen being available, and there was little oxygen available on the early Earth." It is possible that there are anaerobic regions beneath the sea floor in which life forms like those early non-Krebs Cycle microbes may yet exist. To detect and potentially collect samples of life emerging from hydrothermal vents, Flynn and his colleagues created Medusa, a multi-sensor instrument designed for long-term observation of diked vents on the ocean floor. When the vents erupt, Medusa assesses indicators of life within the expelled water. If the results are positive, the observatory collects samples and detaches from the ocean floor, making the long journey to the surface for retrieval by scientists. One of the indicators Medusa measures is the ratio of carbon isotopes in the water, namely carbon-12 and carbon-13. Living organisms preferentially take up carbon-12, Flynn says, so examining the ratio of these isotopes can help to determine the source of carbon in an environment as either biological or non-biological. "On Mars, there is evidence of localized methane in the atmosphere, and that methane could come from biological sources or from geochemical ones," Flynn says. "Determining the background planetary carbon isotope ratios and then evaluating the specific carbon ratios in this methane would help to determine how it was formed." A long-duration observatory similar to Medusa could one day provide essential evidence for or against the presence of life on the Red Planet or beneath the ice-crusted oceans of Europa.

  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. 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.

  1. Initial results of detected methane emissions from landfills in the Los Angeles Basin during the COMEX campaign by the Methane Airborne MAPper (MAMAP) instrument and a greenhouse gas in-situ analyser

    NASA Astrophysics Data System (ADS)

    Krautwurst, Sven; Gerilowski, Konstantin; Kolyer, Richard; Jonsson, Haflidi; Krings, Thomas; Horstjann, Markus; Leifer, Ira; Vigil, Sam; Buchwitz, Michael; Schüttemeyer, Dirk; Fladeland, Matthew M.; Burrows, John P.; Bovensmann, Heinrich

    2015-04-01

    Methane (CH4) is the second most important anthropogenic greenhouse gas beside carbon dioxide (CO2). Significant contributors to the global methane budget are fugitive emissions from landfills. Due to the growing world population, it is expected that the amount of waste and, therefore, waste disposal sites will increase in number and size in parts of the world, often adjacent growing megacities. Besides bottom-up modelling, a variety of ground based methods (e.g., flux chambers, trace gases, radial plume mapping, etc.) have been used to estimate (top-down) these fugitive emissions. Because landfills usually are large, sometimes with significant topographic relief, vary temporally, and leak/emit heterogeneously across their surface area, assessing total emission strength by ground-based techniques is often difficult. In this work, we show how airborne based remote sensing measurements of the column-averaged dry air mole fraction of CH4 can be utilized to estimate fugitive emissions from landfills in an urban environment by a mass balance approach. Subsequently, these emission rates are compared to airborne in-situ horizontal cross section measurements of CH4 taken within the planetary boundary layer (PBL) upwind and downwind of the landfill at different altitudes immediately after the remote sensing measurements were finished. Additional necessary parameters (e.g., wind direction, wind speed, aerosols, dew point temperature, etc.) for the data inversion are provided by a standard instrumentation suite for atmospheric measurements aboard the aircraft, and nearby ground-based weather stations. These measurements were part of the CO2 and Methane EXperiment (COMEX), which was executed during the summer 2014 in California and was co-funded by the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). The remote sensing measurements were taken by the Methane Airborne MAPper (MAMAP) developed and operated by the University of Bremen and

  2. 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.

  3. Methane on Mars: Measurements and Possible Origins

    NASA Technical Reports Server (NTRS)

    Mumma, Michael J.; Villanueva, Geronimo L.; Novak, Robert E.; Radeva, Yana L.; Kaufl, H. Ulrich; Tokunaga, Alan; Encrenaz, Therese; Hartogh, Paul

    2011-01-01

    The presence of abundant methane in Earth's atmosphere (1.6 parts per million) requires sources other than atmospheric chemistry. Living systems produce more than 90% of Earth's atmospheric methane; the balance is of geochemical origin. On Mars, methane has been sought for nearly 40 years because of its potential biological significance, but it was detected only recently [1-5]. Its distribution on the planet is found to be patchy and to vary with time [1,2,4,5], suggesting that methane is released recently from the subsurface in localized areas, and is then rapidly destroyed [1,6]. Before 2000, searchers obtained sensitive upper limits for methane by averaging over much of Mars' dayside hemisphere, using data acquired by Marsorbiting spacecraft (Mariner 9) and Earth-based observatories (Kitt Peak National Observatory, Canada- France-Hawaii Telescope, Infrared Space Observatory). These negative findings suggested that methane should be searched at higher spatial resolution since the local abundance could be significantly larger at active sites. Since 2001, searches for methane have emphasized spatial mapping from terrestrial observatories and from Mars orbit (Mars Express).

  4. MEASUREMENT OF METHANE EMISSIONS FROM UNDERGROUND DISTRIBUTION MAINS AND SERVICES

    EPA Science Inventory

    The paper reports results of measurements of methane emissions from underground distribution mains and services. In the program, leakage from underground distribution systems is estimated by combining leak measurements with historical leak record data and the length of undergroun...

  5. 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.

  6. 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.

  7. 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.

  8. [Isolation of a methane-utilizing bacterium and its application in measuring methane gas].

    PubMed

    Zhao, Gengui; Zheng, Jun; Wen, Guangming; Yang, Suping; Dong, Chuan

    2008-03-01

    A bacterial strain ME16 was isolated from Jinyang Lake in Taiyuan of Shanxi Province, China. Gas chromatography analysis showed that the strain could use methane as the sole carbon and energy source. Based on 16S rDNA sequence analysis, the strain was identified as Pseudomonas aeruginosa. Effects of inoculum size, temperature, methane content and initial pH of media on cell growth were studied. In addition, we examined the response time of methane gas to dissolved oxygen and the relationship between consumption of dissolved oxygen and different methane gas content with PVA-H3BO3 immobilized cell of ME16 using electrochemical method. The optimal conditions for cell growth were 2% inoculum size, 25% methane content, 30 degrees C and pH 6.0. Response time was within 100 s after adding of immobilized cells to reaction system. The linear range of measured methane content was from 0 to 16%, with the correlation coefficient 0.9954. Hence, this strain has potential application in developing of methane biosensor.

  9. 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.

  10. 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.

  11. Quantification of methane emission rates from coal mine ventilation shafts using airborne remote sensing data

    NASA Astrophysics Data System (ADS)

    Krings, T.; Gerilowski, K.; Buchwitz, M.; Hartmann, J.; Sachs, T.; Erzinger, J.; Burrows, J. P.; Bovensmann, H.

    2012-10-01

    The quantification of emissions of the greenhouse gas methane is essential for attributing the roles of anthropogenic activity and natural phenomena in global climate change. Our current measurement systems and networks whilst having improved during the last decades, are deficient in many respects. For example, the emissions from localised and point sources such as landfills or fossil fuel exploration sites are not readily assessed. A tool developed to better understand point sources of the greenhouse gases carbon dioxide and methane is the optical remote sensing instrument MAMAP, operated from aircraft. After a recent instrument modification, retrievals of the column averaged dry air mole fractions for methane XCH4 (or for carbon dioxide XCO2) derived from MAMAP data, have a precision of about 0.4% or better and thus can be used to infer emission rate estimates using an optimal estimation inverse Gaussian plume model or a simple integral approach. CH4 emissions from two coal mine ventilation shafts in Western Germany surveyed during the AIRMETH 2011 measurement campaign are used as examples to demonstrate and assess the value of MAMAP data for quantifying CH4 from point sources. While the knowledge of the wind is an important input parameter in the retrieval of emissions from point sources and is generally extracted from models, additional information from a turbulence probe operated on-board the same aircraft was utilised to enhance the quality of the emission estimates. Although flight patterns were optimised for remote sensing measurements, data from an in-situ analyser for CH4 were found to be in good agreement with retrieved dry columns of CH4 from MAMAP and could be used to investigate and refine underlying assumptions for the inversion procedures. With respect to the total emissions of the mine at the time of the overflight, the inferred emission rate of 50.4 kt CH4 yr-1 has a difference of less than 1% compared to officially reported values by the mine

  12. 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

  13. High spatial resolution imaging of methane and other trace gases with the airborne Hyperspectral Thermal Emission Spectrometer (HyTES)

    NASA Astrophysics Data System (ADS)

    Hulley, Glynn C.; Duren, Riley M.; Hopkins, Francesca M.; Hook, Simon J.; Vance, Nick; Guillevic, Pierre; Johnson, William R.; Eng, Bjorn T.; Mihaly, Jonathan M.; Jovanovic, Veljko M.; Chazanoff, Seth L.; Staniszewski, Zak K.; Kuai, Le; Worden, John; Frankenberg, Christian; Rivera, Gerardo; Aubrey, Andrew D.; Miller, Charles E.; Malakar, Nabin K.; Sánchez Tomás, Juan M.; Holmes, Kendall T.

    2016-06-01

    Currently large uncertainties exist associated with the attribution and quantification of fugitive emissions of criteria pollutants and greenhouse gases such as methane across large regions and key economic sectors. In this study, data from the airborne Hyperspectral Thermal Emission Spectrometer (HyTES) have been used to develop robust and reliable techniques for the detection and wide-area mapping of emission plumes of methane and other atmospheric trace gas species over challenging and diverse environmental conditions with high spatial resolution that permits direct attribution to sources. HyTES is a pushbroom imaging spectrometer with high spectral resolution (256 bands from 7.5 to 12 µm), wide swath (1-2 km), and high spatial resolution (˜ 2 m at 1 km altitude) that incorporates new thermal infrared (TIR) remote sensing technologies. In this study we introduce a hybrid clutter matched filter (CMF) and plume dilation algorithm applied to HyTES observations to efficiently detect and characterize the spatial structures of individual plumes of CH4, H2S, NH3, NO2, and SO2 emitters. The sensitivity and field of regard of HyTES allows rapid and frequent airborne surveys of large areas including facilities not readily accessible from the surface. The HyTES CMF algorithm produces plume intensity images of methane and other gases from strong emission sources. The combination of high spatial resolution and multi-species imaging capability provides source attribution in complex environments. The CMF-based detection of strong emission sources over large areas is a fast and powerful tool needed to focus on more computationally intensive retrieval algorithms to quantify emissions with error estimates, and is useful for expediting mitigation efforts and addressing critical science questions.

  14. A simple headspace equilibration method for measuring dissolved methane

    USGS Publications Warehouse

    Magen, C; Lapham, L.L.; Pohlman, John W.; Marshall, Kristin N.; Bosman, S.; Casso, Michael; Chanton, J.P.

    2014-01-01

    Dissolved methane concentrations in the ocean are close to equilibrium with the atmosphere. Because methane is only sparingly soluble in seawater, measuring it without contamination is challenging for samples collected and processed in the presence of air. Several methods for analyzing dissolved methane are described in the literature, yet none has conducted a thorough assessment of the method yield, contamination issues during collection, transport and storage, and the effect of temperature changes and preservative. Previous extraction methods transfer methane from water to gas by either a "sparge and trap" or a "headspace equilibration" technique. The gas is then analyzed for methane by gas chromatography. Here, we revisit the headspace equilibration technique and describe a simple, inexpensive, and reliable method to measure methane in fresh and seawater, regardless of concentration. Within the range of concentrations typically found in surface seawaters (2-1000 nmol L-1), the yield of the method nears 100% of what is expected from solubility calculation following the addition of known amount of methane. In addition to being sensitive (detection limit of 0.1 ppmv, or 0.74 nmol L-1), this method requires less than 10 min per sample, and does not use highly toxic chemicals. It can be conducted with minimum materials and does not require the use of a gas chromatograph at the collection site. It can therefore be used in various remote working environments and conditions.

  15. Development of a Mid-Infrared Laser for Range-Resolved Methane DIAL Measurements

    NASA Astrophysics Data System (ADS)

    Brandt, S.; Hannun, R. A.; Smith, J. B.; Dykema, J. A.; Witinski, M. F.; Anderson, J. G.

    2013-12-01

    Obtaining a global, homogenous observational record of atmospheric methane mixing ratio as a function of altitude constitutes a challenging experimental problem. The Total Carbon Column Observing Network (TCCON) as well as several climate satellites such as SCIAMACHY provide global data of ground-level concentrations and atmospheric column averages, mapping the global methane content as part of the carbon cycle. However, recent data from the HIAPER Pole-to-Pole Observations mission (HIPPO) reveals highly variable spatial structure within the vertical profile, that is not captured by satellite or ground-based in situ data. This underscores the need for new approaches for range-resolved methane detection. Differential Absorption LIDAR (DIAL) has proven to be a viable technique for range-resolved greenhouse gas measurements from both ground-based and airborne platforms. In order to achieve the necessary vertical resolution for long-range methane measurements, a high-power, pulsed laser system in the mid-IR has been developed. The optical set-up includes a single-frequency Nd:YAG laser, which pumps a non-linear crystal to generate broadly tunable, mid-IR pulses via Optical Parametric Generation (OPG). A detailed sensitivity analysis, including computational estimates of the requirements for laser linewidth, spectral purity, and frequency stability and an examination of different spectral regions in the mid-IR, will be presented. Depending on the deployment location of such a ground-based DIAL observing system, these measurements would make substantial contributions to a range of carbon cycle science questions, including monitoring of national emissions inventories and quantifying potential increases in methane emissions from natural reservoirs due to changing climate.

  16. Online dissolved methane and total dissolved sulfide measurement in sewers.

    PubMed

    Liu, Yiwen; Sharma, Keshab R; Fluggen, Markus; O'Halloran, Kelly; Murthy, Sudhir; Yuan, Zhiguo

    2015-01-01

    Recent studies using short-term manual sampling of sewage followed by off-line laboratory gas chromatography (GC) measurement have shown that a substantial amount of dissolved methane is produced in sewer systems. However, only limited data has been acquired to date due to the low frequency and short span of this method, which cannot capture the dynamic variations of in-sewer dissolved methane concentrations. In this study, a newly developed online measuring device was used to monitor dissolved methane concentrations at the end of a rising main sewer network, over two periods of three weeks each, in summer and early winter, respectively. This device uses an online gas-phase methane sensor to measure methane under equilibrium conditions after being stripped from the sewage. The data are then converted to liquid-phase methane concentrations according to Henry's Law. The detection limit and range are suitable for sewer application and can be adjusted by varying the ratio of liquid-to-gas phase volume settings. The measurement presented good linearity (R² > 0.95) during field application, when compared to off-line measurements. The overall data set showed a wide variation in dissolved methane concentration of 5-15 mg/L in summer and 3.5-12 mg/L in winter, resulting in a significant average daily production of 24.6 and 19.0 kg-CH₄/d, respectively, from the network with a daily average sewage flow of 2840 m³/day. The dissolved methane concentration demonstrated a clear diurnal pattern coinciding with flow and sulfide fluctuation, implying a relationship with the wastewater hydraulic retention time (HRT). The total dissolved sulfide (TDS) concentration in sewers can be determined simultaneously with the same principle.

  17. MAMM (Methane and other greenhouse gases in the Arctic - Measurements, process studies and Modelling) progress report

    NASA Astrophysics Data System (ADS)

    Nisbet, E. G.; Pyle, J. A.

    2012-12-01

    MAMM consortium (led by JA Pyle, Univ. Cambridge, with partners from Univ. East Anglia; Univ. Manchester; Royal Holloway, Univ. of London; NERC Centre for Ecology and Hydrology). The UK MAMM project (Methane and other greenhouse gases in the Arctic - Measurements, process studies and Modelling) is designed to improve quantitative knowledge of Arctic methane and other greenhouse gases from various sources (e.g. wetlands, natural gas, clathrates), to determine magnitudes and spatial distributions, and to develop process understanding (e.g. dependence of fluxes on temperature). In Arctic Finland, Sweden, Norway and Spitsbergen, intensive low-level aircraft campaigns (flights in spring, summer, autumn 2012 and 2013, with the UK FAAM BAe146 aircraft) are designed to measure concentrations of CH4 and other gases across the Arctic by time and location, with in situ sampling for δ13CCH4 at selected sites on land (Zeppelin, Pallas, Alert) and Keeling-plot diel determination of wetland source signatures. High altitude flights sampled stratosphere-troposphere exchange in the Arctic to assess the impact of the polar vortex on methane isotope budgets. Methane column profiles are measured by combining ground based eddy covariance and chamber measurements with aircraft measurements, using a landscape-scale box model approach and flying up and downwind of source regions. Airborne remote sensing is being used to retrieve CH4 columns for comparison with in-situ profiles and testing of hyperspectral retrieval methods from satellite platforms. Longer-term time series measurements are also being established in Kjølnes, northern Norway, for a range of greenhouse and related species via continuous or flask/bag sampling. Modelling studies are in progress to assess the overall Arctic influence on the global methane budget, including detailed back-trajectory analysis of the measurements, especially the isotopic data, to identify sources of methane by location, type (e.g. gasfield, wetland

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Monitoring of Carbon Dioxide and Methane Plumes from Combined Ground-Airborne Sensors

    NASA Astrophysics Data System (ADS)

    Jacob, Jamey; Mitchell, Taylor; Honeycutt, Wes; Materer, Nicholas; Ley, Tyler; Clark, Peter

    2016-11-01

    A hybrid ground-airborne sensing network for real-time plume monitoring of CO2 and CH4 for carbon sequestration is investigated. Conventional soil gas monitoring has difficulty in distinguishing gas flux signals from leakage with those associated with meteorologically driven changes. A low-cost, lightweight sensor system has been developed and implemented onboard a small unmanned aircraft and is combined with a large-scale ground network that measures gas concentration. These are combined with other atmospheric diagnostics, including thermodynamic data and velocity from ultrasonic anemometers and multi-hole probes. To characterize the system behavior and verify its effectiveness, field tests have been conducted with simulated discharges of CO2 and CH4 from compressed gas tanks to mimic leaks and generate gaseous plumes, as well as field tests over the Farnsworth CO2-EOR site in the Anadarko Basin. Since the sensor response time is a function of vehicle airspeed, dynamic calibration models are required to determine accurate location of gas concentration in space and time. Comparisons are made between the two tests and results compared with historical models combining both flight and atmospheric dynamics. Supported by Department of Energy Award DE-FE0012173.

  3. Benefits of including methane measurements in selection strategies.

    PubMed

    Robinson, D L; Oddy, V H

    2016-09-01

    Estimates of genetic/phenotypic covariances and economic values for slaughter weight, growth, feed intake and efficiency, and three potential methane traits were compiled to explore the effect of incorporating methane measurements in breeding objectives for cattle and meat sheep. The cost of methane emissions was assumed to be zero (scenario A), A$476/t (based on A$14/t CO equivalent and methane's 100-yr global warming potential [GWP] of 34; scenario B), or A$2,580/t (A$30/t CO equivalent combined with methane's 20-yr GWP of 86; scenario C). Methane traits were methane yield (MY; methane production divided by feed intake based on measurements over 1 d in respiration chambers) or short-term measurements of methane production adjusted for live weight (MPadjWt) in grazing animals, e.g., 40-60 min measurements in portable accumulation chambers (PAC) on 1 or 3 occasions, or measurements for 1 wk using a GreenFeed Emissions Monitor (GEM) on 1 or 3 occasions. Feed costs included the cost of maintaining the breeding herd and growth from weaning to slaughter. Sheep were assumed to be grown and finished on pasture (A$50/t DM). Feed costs for cattle included 365 d on pasture for the breeding herd and averages of 200 d postweaning grow-out on pasture and 100 d feedlot finishing. The greatest benefit of including methane in the breeding objective for both sheep and cattle was as a proxy for feed intake. For cattle, 3 GEM measurements were estimated to increase profit from 1 round of selection in scenario A (no payment for methane) by A$6.24/animal (from A$20.69 to A$26.93) because of reduced feed costs relative to gains in slaughter weight and by A$7.16 and A$12.09/animal, respectively, for scenarios B and C, which have payments for reduced methane emissions. For sheep, the improvements were more modest. Returns from 1 round of selection (no methane measurements) were A$5.06 (scenario A), A$4.85 (scenario B), and A$3.89 (scenario C) compared to A$5.26 (scenario A), A$5

  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. 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.

  8. 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.

  9. 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.

  10. Laboratory measurements and methane photochemistry modeling

    NASA Technical Reports Server (NTRS)

    Romani, P. N.

    1990-01-01

    Methane is photolyzed by the solar UV in the stratosphere of Saturn. Subsequent photochemistry leads to the production of acetylene (C2H2) and diacetylene (C4H2). These species are produced where it is relatively warm (T is greater than or equal to 140 K), but the tropopause temperature of Saturn (approximately 80 K) is low enough that these two species may freeze out to their respective ices. Numerical models which include both photochemistry and condensation loss make predictions about the mixing ratios of these species and haze production rates. These models are dependent upon knowing reaction pathways and their associated kinetic reaction rate constants and vapor pressures. How uncertainties in the chemistry and improvements in the vapor pressures affect model predictions for Saturn are discussed.

  11. 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.

  12. Continuous Seasonal River Ebullition Measurements Linked to Sediment Methane Formation.

    PubMed

    Wilkinson, Jeremy; Maeck, Andreas; Alshboul, Zeyad; Lorke, Andreas

    2015-11-17

    Laboratory sediment incubations and continuous ebullition monitoring over an annual cycle in the temperate Saar River, Germany confirm that impounded river zones can produce and emit methane at high rates (7 to 30 (g CH4 m(-3) d(-1)) at 25 °C and 270 to 700 (g CH4 m(-2) yr(-1)), respectively). Summer methane ebullition (ME) peaks were a factor of 4 to 10 times the winter minima, and sediment methane formation was dominated by the upper sediment (depths of 0.14 to 0.2 m). The key driver of the seasonal ME dynamics was temperature. An empirical model relating methane formation to temperature and sediment depth, derived from the laboratory incubations, reproduced the measured daily ebullition from winter to midsummer, although late summer and autumn simulated ME exceeded the observed ME. A possible explanation for this was substrate limitation. We recommend measurements of methanogenically available carbon sources to identify substrate limitation and help characterize variation in methane formation with depth and from site to site.

  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. Modeling and Measurements of Atmospheric Methane at Four Corners, NM

    NASA Astrophysics Data System (ADS)

    Costigan, K. R.; Lindenmaier, R.; Dubey, M. K.

    2014-12-01

    Methane (CH4) fugitive emissions from fossil energy mining remain highly uncertain and scrutinized with the rapid expansion in domestic production by hydraulic fracturing. Top down observational studies of reported bottom up inventories are limited, but the latter may be biased low. We focus on the Four Corners region of the Southwestern United States, a region with extensive coal bed methane production, to verify its current emissions. At our site we measured methane over a range of scales using ground-based, in-situ instruments and a Fourier Transform Spectrometer (FTS), which is part of the Total Carbon Column Observing Network (TCCON). Measurements of CH4 produced much higher concentrations of methane in this rural area than previously expected. The diurnal variation and wind direction dependence in the CH4 concentrations suggest a source location tied to topographically induced winds and consistent with oil and gas production. This paper presents the results of WRF-Chem simulations that are performed to simulate methane concentrations in this region. Emissions from the Emissions Database for Global Atmospheric Research (EDGAR) indicate large CH4 emissions, associated with the gas production and distribution sector, in one 0.1 x 0.1 degree grid cell within the region and these emissions are employed in the simulations. A series of six simulations are run at two-month intervals during 2012. Each simulates a six-day time series to demonstrate the diurnal and seasonal characteristics of the methane concentrations that would be expected at the FTS location, from the sources reported in the EDGAR data set. The results of these simulations will be presented, along with the implications for interpretation of the FTS measurements. We will also interpret our FTS measurements of ethane (C2H6), which is emitted only from fossil fuel mining, to attribute leaks.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. ISOTOPIC RATIOS IN TITAN's METHANE: MEASUREMENTS AND MODELING

    SciTech Connect

    Nixon, C. A.; Achterberg, R. K.; Temelso, B.; Vinatier, S.; Bezard, B.; Coustenis, A.; Teanby, N. A.; Mandt, K. E.; Sherrill, C. D.; Irwin, P. G. J.; Jennings, D. E.; Romani, P. N.; Flasar, F. M.

    2012-04-20

    The existence of methane in Titan's atmosphere ({approx}6% level at the surface) presents a unique enigma, as photochemical models predict that the current inventory will be entirely depleted by photochemistry in a timescale of {approx}20 Myr. In this paper, we examine the clues available from isotopic ratios ({sup 12}C/{sup 13}C and D/H) in Titan's methane as to the past atmosphere history of this species. We first analyze recent infrared spectra of CH{sub 4} collected by the Cassini Composite Infrared Spectrometer, measuring simultaneously for the first time the abundances of all three detected minor isotopologues: {sup 13}CH{sub 4}, {sup 12}CH{sub 3}D, and {sup 13}CH{sub 3}D. From these we compute estimates of {sup 12}C/{sup 13}C = 86.5 {+-} 8.2 and D/H = (1.59 {+-} 0.33) Multiplication-Sign 10{sup -4}, in agreement with recent results from the Huygens GCMS and Cassini INMS instruments. We also use the transition state theory to estimate the fractionation that occurs in carbon and hydrogen during a critical reaction that plays a key role in the chemical depletion of Titan's methane: CH{sub 4} + C{sub 2}H {yields} CH{sub 3} + C{sub 2}H{sub 2}. Using these new measurements and predictions we proceed to model the time evolution of {sup 12}C/{sup 13}C and D/H in Titan's methane under several prototypical replenishment scenarios. In our Model 1 (no resupply of CH{sub 4}), we find that the present-day {sup 12}C/{sup 13}C implies that the CH{sub 4} entered the atmosphere 60-1600 Myr ago if methane is depleted by chemistry and photolysis alone, but much more recently-most likely less than 10 Myr ago-if hydrodynamic escape is also occurring. On the other hand, if methane has been continuously supplied at the replenishment rate then the isotopic ratios provide no constraints, and likewise for the case where atmospheric methane is increasing. We conclude by discussing how these findings may be combined with other evidence to constrain the overall history of the atmospheric

  1. Isotopic Ratios in Titan's Methane: Measurements and Modeling

    NASA Technical Reports Server (NTRS)

    Nixon, C. A.; Temelso, B.; Vinatier, S.; Teanby, N. A.; Bezard, B.; Achterberg, R. K.; Mandt, K. E.; Sherrill, C. D.; Irwin, P. G.; Jennings, D. E.; Romani, P. N.; Coustenis, A.; Flasar, F. M.

    2012-01-01

    The existence of methane in Titan's atmosphere (approx. 6% level at the surface) presents a unique enigma, as photochemical models predict that the current inventory will be entirely depleted by photochemistry in a timescale of approx 20 Myr. In this paper, we examine the clues available from isotopic ratios (C-12/C-13 and D/H) in Titan's methane as to the past atmosphere history of this species. We first analyze recent infrared spectra of CH4 collected by the Cassini Composite Infrared Spectrometer, measuring simultaneously for the first time the abundances of all three detected minor isotopologues: (13)CH4, (12)CH3D, and (13)CH3D. From these we compute estimates of C-12/C-13 = 86.5 +/- 8.2 and D/H = (1.59 +/- 0.33) x 10(exp -4) , in agreement with recent results from the Huygens GCMS and Cassini INMS instruments. We also use the transition state theory to estimate the fractionation that occurs in carbon and hydrogen during a critical reaction that plays a key role in the chemical depletion of Titan's methane: CH4 + C2H yields CH3 + C2H2. Using these new measurements and predictions we proceed to model the time evolution of C-12/C-13 and D/H in Titan's methane under several prototypical replenishment scenarios. In our Model 1 (no resupply of CH4), we find that the present-day C-12/C-13 implies that the CH4 entered the atmosphere 60-1600 Myr ago if methane is depleted by chemistry and photolysis alone, but much more recently-most likely less than 10 Myr ago-if hydrodynamic escape is also occurring. On the other hand, if methane has been continuously supplied at the replenishment rate then the isotopic ratios provide no constraints, and likewise for the case where atmospheric methane is increasing, We conclude by discussing how these findings may be combined with other evidence to constrain the overall history of the atmospheric methane.

  2. Measurement and prediction of enteric methane emission.

    PubMed

    Sejian, Veerasamy; Lal, Rattan; Lakritz, Jeffrey; Ezeji, Thaddeus

    2011-01-01

    The greenhouse gas (GHG) emissions from the agricultural sector account for about 25.5% of total global anthropogenic emission. While CO(2) receives the most attention as a factor relative to global warming, CH(4), N(2)O and chlorofluorocarbons (CFCs) also cause significant radiative forcing. With the relative global warming potential of 25 compared with CO(2), CH(4) is one of the most important GHGs. This article reviews the prediction models, estimation methodology and strategies for reducing enteric CH(4) emissions. Emission of CH(4) in ruminants differs among developed and developing countries, depending on factors like animal species, breed, pH of rumen fluid, ratio of acetate:propionate, methanogen population, composition of diet and amount of concentrate fed. Among the ruminant animals, cattle contribute the most towards the greenhouse effect through methane emission followed by sheep, goats and buffalos, respectively. The estimated CH(4) emission rate per cattle, buffaloe, sheep and goat in developed countries are 150.7, 137, 21.9 and 13.7 (g/animal/day) respectively. However, the estimated rates in developing countries are significantly lower at 95.9 and 13.7 (g/animal/day) per cattle and sheep, respectively. There exists a strong interest in developing new and improving the existing CH(4) prediction models to identify mitigation strategies for reducing the overall CH(4) emissions. A synthesis of the available literature suggests that the mechanistic models are superior to empirical models in accurately predicting the CH(4) emission from dairy farms. The latest development in prediction model is the integrated farm system model which is a process-based whole-farm simulation technique. Several techniques are used to quantify enteric CH(4) emissions starting from whole animal chambers to sulfur hexafluoride (SF6) tracer techniques. The latest technology developed to estimate CH(4) more accurately is the micrometeorological mass difference technique. Because

  3. Measurement and prediction of enteric methane emission

    NASA Astrophysics Data System (ADS)

    Sejian, Veerasamy; Lal, Rattan; Lakritz, Jeffrey; Ezeji, Thaddeus

    2011-01-01

    The greenhouse gas (GHG) emissions from the agricultural sector account for about 25.5% of total global anthropogenic emission. While CO2 receives the most attention as a factor relative to global warming, CH4, N2O and chlorofluorocarbons (CFCs) also cause significant radiative forcing. With the relative global warming potential of 25 compared with CO2, CH4 is one of the most important GHGs. This article reviews the prediction models, estimation methodology and strategies for reducing enteric CH4 emissions. Emission of CH4 in ruminants differs among developed and developing countries, depending on factors like animal species, breed, pH of rumen fluid, ratio of acetate:propionate, methanogen population, composition of diet and amount of concentrate fed. Among the ruminant animals, cattle contribute the most towards the greenhouse effect through methane emission followed by sheep, goats and buffalos, respectively. The estimated CH4 emission rate per cattle, buffaloe, sheep and goat in developed countries are 150.7, 137, 21.9 and 13.7 (g/animal/day) respectively. However, the estimated rates in developing countries are significantly lower at 95.9 and 13.7 (g/animal/day) per cattle and sheep, respectively. There exists a strong interest in developing new and improving the existing CH4 prediction models to identify mitigation strategies for reducing the overall CH4 emissions. A synthesis of the available literature suggests that the mechanistic models are superior to empirical models in accurately predicting the CH4 emission from dairy farms. The latest development in prediction model is the integrated farm system model which is a process-based whole-farm simulation technique. Several techniques are used to quantify enteric CH4 emissions starting from whole animal chambers to sulfur hexafluoride (SF6) tracer techniques. The latest technology developed to estimate CH4 more accurately is the micrometeorological mass difference technique. Because the conditions under which

  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. 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

  8. 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.

  9. Methane emissions measured directly from grazing livestock in New Zealand

    NASA Astrophysics Data System (ADS)

    Lassey, Keith R.; Ulyatt, Marcus J.; Martin, Ross J.; Walker, Carolyn F.; David Shelton, I.

    We report measurements of methane emissions from individual ruminant livestock-both sheep and dairy cows-grazing pasture typical of New Zealand lowlands in the temperate southwest Pacific. These are the first measurements reported from grazing sheep, and among the first from grazing cattle. The measurement technique, developed at Washington State University, enables emission rates to be determined from analyses of "breath" samples collected while grazing. More than 250 measurements of daily methane emission from 50 sheep (8 months old) were made, with flock-mean emission 18.9 ± 0.8 g hd -1 d -1. Although emissions were weakly correlated with feed intake, they represented a 4.6 ± 0.1 % average loss of gross dietary energy. The corresponding mean emission based on 40 measurements of daily emissions from 10 lactating dairy cows was 263 ± 10 g hd -1 d -1, approximately 6.2% of estimated gross energy intake. A notable feature was the large inter-sheep variability in daily methane emission (factor of 1.4 range) that could not be attributed to variable intake. This would appear to suggest an appreciable diversity of methanogenetic response to digestion, and may be significant in the search for strategies to control emissions of this greenhouse gas.

  10. 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%.

  11. 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.

  12. 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.

  13. 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.

  14. Atmospheric Methane Measurements from an Aircraft Based at NASA Ames: Five Years of Observations by the AJAX Project

    NASA Technical Reports Server (NTRS)

    Iraci, Laura

    2016-01-01

    The Alpha Jet Atmospheric eXperiment (AJAX) is a research project based at Moffett Field, CA, which collects airborne measurements of ozone, carbon dioxide, methane, water vapor, and formaldehyde, as well as 3-D winds, temperature, pressure, and location. Since its first science flight in 2011, AJAX has developed a wide a variety of mission types, combining vertical profiles (from approx. 8 km to near surface),boundary layer legs, and plume sampling as needed. With an ongoing five-year data set, the team has sampled over 160 vertical profiles, a dozen wildfires, and numerous stratospheric ozone intrusions. This talk will present an overview of our flights flown to date, with particular focus on methane observations in the San Francisco Bay Area, Sacramento, and the delta region.

  15. 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.

  16. 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

  17. 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.

  18. Absolute Measurements Of Methane On Mars: The Current Status.

    NASA Astrophysics Data System (ADS)

    Mumma, Michael J.; Villanueva, G. L.; Novak, R. E.; Hewagama, T.; Bonev, B. P.; DiSanti, M. A.; Smith, M. D.

    2008-09-01

    Our study of methane on Mars now extends over three Mars years, sampling a wide range of seasons with significant spatial coverage. Three spectrometer-telescope combinations were used. With the spectrometer slit oriented North-South on the planet, we obtain simultaneous spectra at latitudes along the central meridian. Successive longitudes are sampled as the planet rotates, and the combination then permits partial mapping of the planet. We earlier reported differential detections of methane and water on Mars. Here, we present absolute extractions of methane, based on improved analytical procedures developed since 2005. We now identify and correct instrumental effects such as variations in resolving power along the slit, second-order optical fringe removal, and correction of (minor) internal scattered light. We synthesize the fully-resolved terrestrial transmittance spectrum, convolve it to the instrumental resolution, and subtract it from the measured Mars-Earth spectrum. Fraunhofer lines are removed from the residual Mars spectra along with spectral lines of water and of (newly identified by us) carbon dioxide isotopomers. The residuals are then inspected for signatures of methane and other possible trace constituents such as HDO and H2O (Villanueva et al., this Conference). On certain dates, the residual spectra display spectral lines at the Doppler-shifted positions expected for methane on Mars. The positive indications favor certain seasons (e.g., Ls = 121° & 155°) and locations. Mixing ratios derived from those residuals (up to 60 ppb) greatly exceed upper limits obtained at other seasons (e.g., < 3ppb at Ls = 17°) these variations could be consistent with episodic release. The CH4 spatial extent requires transport over large distances (coupled with eddy diffusion), and destruction lifetimes of order one year. Details will be presented and implications will be discussed. This work was supported by NASA's Astrobiology, Planetary Astronomy, and Postdoctoral

  19. 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.

  20. 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.

  1. 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); ...

  2. 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.

  3. Methane mitigation in cities: how new measurements and partnerships can contribute to emissions reduction strategies

    NASA Astrophysics Data System (ADS)

    Hopkins, F. M.; Bush, S. E.; Ehleringer, J. R.; Lai, C. T.; Rambo, J. P.; Wiggins, E. B.; Miu, J. C. L.; Carranza, V.; Randerson, J. T.

    2014-12-01

    Cities generate a large fraction of anthropogenic methane emissions that are increasing with urbanization and greater reliance on natural gas as fuel. New measurements of methane in cities suggest an as-yet unrealized potential for city-scale methane mitigation. We present high-resolution methane observations from four cities in North America to demonstrate the utility of methane surveys for identifying urban methane sources. We used portable, continuous on-road measurements to determine the spatial distribution of methane in Fairbanks, Los Angeles, Salt Lake City, and San Diego. Across cities, methane tended to be highly concentrated in space, suggesting discrete, point emission sources. Elevated methane levels were found near known emission sources, such as landfills, wastewater treatment facilities, and natural gas-fueled power plants, and revealed the location of fugitive leaks in natural gas infrastructure. The mix of sources and sizes of methane leaks varied among cities, highlighting a need for locally adaptive emissions regulation. Urban methane observations can inform anthropogenic processes in development of methane mitigation strategies. We discuss specific examples of how continuous atmospheric measurements can enhance the design of mitigation strategies in these cities, and potential contributions of these approaches to cross-sectoral efforts to reduce methane emissions at the city level.

  4. The 4-Corners methane hotspot: Mapping CH4 plumes at 60km through 1m resolution using space- and airborne spectrometers

    NASA Astrophysics Data System (ADS)

    Frankenberg, C.; Thorpe, A. K.; Hook, S. J.; Green, R. O.; Thompson, D. R.; Kort, E. A.; Hulley, G. C.; Vance, N.; Bue, B. D.; Aubrey, A. D.

    2015-12-01

    The SCIAMACHY instrument onboard the European research satellite ENVISAT detected a large methane hotspot in the 4-Corners area, specifically in New Mexico and Colorado. Total methane emissions in this region were estimated to be on the order of 0.5Tg/yr, presumably related to coal-bed methane exploration. Here, we report on NASA efforts to augment the TOPDOWN campaign intended to enable regional methane source inversions and identify source types in this area. The Jet Propulsion Laboratory was funded to fly two airborne imaging spectrometers, viz. AVIRIS-NG and HyTES. In April 2015, we used both instruments to continuously map about 2000km2 in the 4-Corners area at 1-5m spatial resolution, with special focus on the most enhanced areas as observed from space. During our weeklong campaign, we detected more than 50 isolated and strongly enhanced methane plumes, ranging from coal mine venting shafts and gas processing facilities through individual well-pads, pipeline leaks and outcrop. Results could be immediately shared with ground-based teams and TOPDOWN aircraft so that ground-validation and identification was feasible for a number of sources. We will provide a general overview of the JPL-led mapping campaign efforts and show individual results, derive source strength estimates and discuss how the results fit in with space borne estimates.

  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. Measurements of methane emissions from natural gas gathering facilities and processing plants: measurement results.

    PubMed

    Mitchell, Austin L; Tkacik, Daniel S; Roscioli, Joseph R; Herndon, Scott C; Yacovitch, Tara I; Martinez, David M; Vaughn, Timothy L; Williams, Laurie L; Sullivan, Melissa R; Floerchinger, Cody; Omara, Mark; Subramanian, R; Zimmerle, Daniel; Marchese, Anthony J; Robinson, Allen L

    2015-03-03

    Facility-level methane emissions were measured at 114 gathering facilities and 16 processing plants in the United States natural gas system. At gathering facilities, the measured methane emission rates ranged from 0.7 to 700 kg per hour (kg/h) (0.6 to 600 standard cubic feet per minute (scfm)). Normalized emissions (as a % of total methane throughput) were less than 1% for 85 gathering facilities and 19 had normalized emissions less than 0.1%. The range of methane emissions rates for processing plants was 3 to 600 kg/h (3 to 524 scfm), corresponding to normalized methane emissions rates <1% in all cases. The distributions of methane emissions, particularly for gathering facilities, are skewed. For example, 30% of gathering facilities contribute 80% of the total emissions. Normalized emissions rates are negatively correlated with facility throughput. The variation in methane emissions also appears driven by differences between inlet and outlet pressure, as well as venting and leaking equipment. Substantial venting from liquids storage tanks was observed at 20% of gathering facilities. Emissions rates at these facilities were, on average, around four times the rates observed at similar facilities without substantial venting.

  7. Methane source identification in Boston, Massachusetts using isotopic and ethane measurements

    NASA Astrophysics Data System (ADS)

    Down, A.; Jackson, R. B.; Plata, D.; McKain, K.; Wofsy, S. C.; Rella, C.; Crosson, E.; Phillips, N. G.

    2012-12-01

    Methane has substantial greenhouse warming potential and is the principle component of natural gas. Fugitive natural gas emissions could be a significant source of methane to the atmosphere. However, the cumulative magnitude of natural gas leaks is not yet well constrained. We used a combination of point source measurements and ambient monitoring to characterize the methane sources in the Boston urban area. We developed distinct fingerprints for natural gas and multiple biogenic methane sources based on hydrocarbon concentration and isotopic composition. We combine these data with periodic measurements of atmospheric methane and ethane concentration to estimate the fractional contribution of natural gas and biogenic methane sources to the cumulative urban methane flux in Boston. These results are used to inform an inverse model of urban methane concentration and emissions.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. New Results from Frequency and Energy Reference Measurements during the first Test Flight with the Airborne Integrated Path Differential Absorption Lidar System CHARM-F

    NASA Astrophysics Data System (ADS)

    Ehret, G.; Fix, A.; Amediek, A.; Quatrevalet, M.

    2015-12-01

    The Integrated Path Differential Absorption Lidar (IPDA) technique is regarded as a suitable means for the measurement of methane and carbon dioxide columns from satellite or aircraft platforms with unprecedented accuracy. Currently, the German-French methane mission MERLIN (Methan Remote Lidar Mission) is prepared. At the same time CHARM-F, an aircraft installed system has been developed at DLR as an airborne demonstrator for a spaceborne greenhouse gas mission. Both use e.g. optical parametric oscillators (OPOs) in a double-pulse mode as the transmitter. Of particular importance for both instruments are the sub-modules required for the frequency stabilization of the transmitter wavelength and, since the IPDA technique, in contrast to DIAL, requires the exact knowledge of the energy ratio of outgoing on-line. The coherence of the lidar transmitter gives rise to speckle effects which have to be considered for the monitoring of the energy ratio of outgoing on- and off-line pulses. For the frequency reference of CHARM-F, a very successful stabilization scheme has been developed which will also serve as the reference for MERLIN. In Spring 2015, CHARM-F was flown aboard the German HALO aircraft for the first time which enables a detailed view on the performance of both the energy calibration and frequency reference subsystems under real flight conditions. As an initial quality check we will compared the airborne results to previous lab measurements which have been performed under stable environmental conditions.

  16. 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.

  17. 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.

  18. 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

  19. 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).

  20. New off-line aircraft instrumentation for non-methane hydrocarbon measurements.

    PubMed

    Bechara, Joelle; Borbon, Agnès; Jambert, Corinne; Perros, Pascal E

    2008-11-01

    New off-line instrumentation was developed to implement measurements of non-methane hydrocarbons (NMHC) on (French) research aircraft. NMHC are collected on multisorbent tubes by AMOVOC (Airborne Measurements Of Volatile Organic Compounds), a new automatic sampler. AMOVOC is a versatile and portable sampler targeting a wide range of NMHC at high frequency (sampling time of 10 min). Multisorbent tubes are analyzed on the ground by short-path thermal desorption coupled with gas chromatography and mass spectrometry. The development and optimization of both NMHC sampling and analysis are reported here. On the one hand, the paper points out technical choices that were made according to aircraft constraints and avoiding sample loss or contamination. On the other hand, it describes analytical optimization, tube storage stability, and moisture removal. The method shows high selectivity, sensitivity (limit of detection less than 10 ppt) and precision (less than 24%). Finally, NMHC data collected on French aircraft during the African Monsoon Multidisciplinary Analysis campaign are reported for the first time. The results highlight instrumentation validity and protocol efficiency for NMHC measurements in the lower and upper troposphere.

  1. 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%.

  2. Direct measurements of methane emissions from grazing and feedlot cattle.

    PubMed

    Harper, L A; Denmead, O T; Freney, J R; Byers, F M

    1999-06-01

    Methane (CH4) emissions from animals represent a significant contribution to anthropogenically produced radiatively active trace gases. Global and national CH4 budgets currently use predictive models based on emission data from laboratory experiments to estimate the magnitude of the animal source. This paper presents a method for measuring CH4 from animals under undisturbed field conditions and examines the performance of common models used to simulate field conditions. A micrometeorological mass difference technique was developed to measure CH4 production by cattle in pasture and feedlot conditions. Measurements were made continuously under field conditions, semiautomatically for several days, and the technique was virtually nonintrusive. The method permits a relatively large number of cattle to be sampled. Limitations include light winds (less than approximately 2 m/s), rapid wind direction changes, and high-precision CH4 gas concentration measurement. Methane production showed a marked periodicity, with greater emissions during periods of rumination as opposed to grazing. When the cattle were grazed on pasture, they produced .23 kg CH4 x animal(-1) x d(-1), which corresponded to the conversion of 7.7 to 8.4% of gross energy into CH4. When the same cattle were fed a highly digestible, high-grain diet, they produced .07 kg CH4 x animal(-1) x d(-1), corresponding to a conversion of only 1.9 to 2.2% of the feed energy to CH4. These measurements clearly document higher CH4 production (about four times) for cattle receiving low-quality, high-fiber diets than for cattle fed high-grain diets. The mass difference method provides a useful tool for "undisturbed" measurements on the influence of feedstuffs and nutritional management practices on CH4 production from animals and for developing improved management practice for enhanced environmental quality.

  3. Mobile measurement of methane: plumes, isotopes and inventory verification

    NASA Astrophysics Data System (ADS)

    Lowry, D.; Zazzeri, G.; Fisher, R. E.; France, J.; Al-Shalaan, A.; Lanoisellé, M.; Nisbet, E. G.

    2015-12-01

    Since 2013 the RHUL group has been identifying methane plumes from major UK sources using a Picarro 2301 coupled to the A0941 mobile module. Once identified the plumes have been sampled by filling Tedlar or Flexfoil bags for later carbon isotopic analysis by high-precision IRMS. This method has ben successfully deployed to isotopically characterize the main anthropogenic methane emitters in the UK (natural gas, coal, landfill, wastewater treatment, cattle; Zazzeri et al., 2015) and during overseas campaigns in eastern Australia (coal, cattle, legacy gas wells) and Kuwait (landfill, wastewater treatment, oil refineries, cattle, camels). This has identified strong similarities of isotopic signature for some sources (landfill, cattle), but large variations for others (natural gas, coal), which must be isotopically resolved at regional scale. Both landfill and natural gas emissions in SE England have tightly-constrained δ13C signatures, averaging -58 ± 3‰ and -36 ± 2‰, respectively, the latter being characteristic of homogenised North Sea gas supply. In contrast, signatures for coal mines in England and Wales fall in a range of 51.2 ± 0.3‰ to 30.9 ± 1.4‰, but can be tightly constrained by region. On a local scale in west London, repeat surveys in the boroughs of Hounslow and Runnymede have been made for comparison with the latest 1x1 km grid UK inventories for 2009 and 2012, which are subdivided by UNECE categories. An excess methane map can be derived for comparison with inventory emissions maps by identifying daily background and binning the excess values from mobile measurements by grid-square. This shows that the spatial distribution of emissions in the UK 2012 inventory is a big improvement on that of 2009. It also suggests that there is an overestimation of emissions from old landfills (closed before 2000 and reliant on a topsoil cap for oxidation), and an underestimation on emissions from currently active landfill cells. Zazzeri, G. et al. (2015

  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. Use of an oxygen-insensitive microscale biosensor for methane to measure methane concentration profiles in a rice paddy.

    PubMed

    Damgaard, L R; Revsbech, N P; Reichardt, W

    1998-03-01

    An oxygen-insensitive microscale biosensor for methane was constructed by furnishing a previously described biosensor with an oxygen guard. The guard consisted of a glass capillary containing heterotrophic bacteria, which consumed oxygen diffusing through the tip membrane, thus preventing it from diffusing into the methane-sensing unit. Oxygen microprofiles were measured through the oxygen guard capillary, demonstrating the principle and limitations of the method. When the tip of the guard capillary was exposed to 100% oxygen at 21 degrees C, heterotrophic oxygen consumption prevented oxygen from diffusing further than 170 mum into the capillary, whereas atmospheric levels of oxygen were consumed within 50 mum. The capacity of the oxygen guard for scavenging oxygen decreased with decreasing temperature, and atmospheric levels of oxygen caused oxygen penetration to 200 mum at 5 degrees C. The sensors could be manufactured with tip diameters as small as 25 mum, and response times were about 1 min at room temperature. Pore water profiles of methane concentrations in a rice paddy soil were measured, and a strong correlation between the depths of oxygen penetration and methane appearance was observed as a function of the light regimen; this finding confirmed the role of microbenthic photosynthesis in limiting methane emissions from surfaces of waterlogged sediments and soils.

  6. Methane emissions measurements of natural gas components using a utility terrain vehicle and portable methane quantification system

    NASA Astrophysics Data System (ADS)

    Johnson, Derek; Heltzel, Robert

    2016-11-01

    Greenhouse Gas (GHG) emissions are a growing problem in the United States (US). Methane (CH4) is a potent GHG produced by several stages of the natural gas sector. Current scrutiny focuses on the natural gas boom associated with unconventional shale gas; however, focus should still be given to conventional wells and outdated equipment. In an attempt to quantify these emissions, researchers modified an off-road utility terrain vehicle (UTV) to include a Full Flow Sampling system (FFS) for methane quantification. GHG emissions were measured from non-producing and remote low throughput natural gas components in the Marcellus region. Site audits were conducted at eleven locations and leaks were identified and quantified at seven locations including at a low throughput conventional gas and oil well, two out-of-service gathering compressors, a conventional natural gas well, a coalbed methane well, and two conventional and operating gathering compressors. No leaks were detected at the four remaining sites, all of which were coal bed methane wells. The total methane emissions rate from all sources measured was 5.3 ± 0.23 kg/hr, at a minimum.

  7. Methane production, emission and possible control measures in the rice agriculture

    NASA Astrophysics Data System (ADS)

    Wang, Mingxing; Shangguan, Xingjian; Shen, Renxing; Reiner, Wassmann; Wolfgang, Seiler

    1993-09-01

    In the rice field methane is produced in the soil layer with depths of 2 25 cm. The vertical profile of methane production rate in the paddy soil during the water covering period differs from that in the paddy soil in dry phase. Only a small part, about 30%, of the produced methane is emitted to the atmosphere through rice plant, air bubbles, and molecular diffusion. Therefore, the methane emission rate from the rice field depends not only on the methane production rate in the soil, but also on the transport efficiency of the rice plant, air bubble formation that in turn depends on the production rate, and molecular diffusion. Field measurements show that methane emission rates from a particular rice field have very large diurnal, seasonal and interannual variations, which are related to soil characteristics, water regime, farming procedure, local climate, and rice growing activities. The relationship between the methane emission rate and the above mentioned factors is very complicated. The emission rates from different rice fields differ greatly not only in the absolute value, but also in the temporal variation patterns. Methane emission rate from the rice field may be significantly reduced by scientific management of fertilizer and irrigation. While the use of SO{4/2-} containing fertilizer and fermented organic fertilizer may reduce the methane emission significantly, the most promising measure for reducing methane emission from rice field is the frequent drainage irrigation procedure.

  8. Measurement of Strontium Monoxide in Methane-Air Flames.

    PubMed

    Wimberly, Bobby J; Hornkohl, James O; Parigger, Christian G

    2017-02-01

    The spectroscopy of alkaline earth metal compounds is stimulated by the use of these compounds in practical areas ranging from technology to medicine. Applications in the field of pyrotechnics were the motivation for a series of flame emission spectroscopy experiments with strontium-containing compounds. Specifically, strontium monoxide (SrO) was studied as a candidate radiator for the diagnosis of methane-air flames. Strontium monoxide emissions have been observed in flames with temperatures in the range 1200 K to 1600 K for two compounds: strontium hydroxide and strontium chloride. Comparisons are made of the measured SrO spectra to simulated spectra in the near-infrared region of 700 nm to 900 nm.

  9. Constraints on oceanic methane emissions west of Svalbard from atmospheric in situ measurements and Lagrangian transport modeling

    PubMed Central

    Myhre, C. Lund; Platt, S. M.; Eckhardt, S.; Hermansen, O.; Schmidbauer, N.; Mienert, J.; Vadakkepuliyambatta, S.; Bauguitte, S.; Pitt, J.; Allen, G.; Bower, K. N.; O'Shea, S.; Gallagher, M. W.; Percival, C. J.; Pyle, J.; Cain, M.; Stohl, A.

    2016-01-01

    Abstract Methane stored in seabed reservoirs such as methane hydrates can reach the atmosphere in the form of bubbles or dissolved in water. Hydrates could destabilize with rising temperature further increasing greenhouse gas emissions in a warming climate. To assess the impact of oceanic emissions from the area west of Svalbard, where methane hydrates are abundant, we used measurements collected with a research aircraft (Facility for Airborne Atmospheric Measurements) and a ship (Helmer Hansen) during the Summer 2014 and for Zeppelin Observatory for the full year. We present a model‐supported analysis of the atmospheric CH4 mixing ratios measured by the different platforms. To address uncertainty about where CH4 emissions actually occur, we explored three scenarios: areas with known seeps, a hydrate stability model, and an ocean depth criterion. We then used a budget analysis and a Lagrangian particle dispersion model to compare measurements taken upwind and downwind of the potential CH4 emission areas. We found small differences between the CH4 mixing ratios measured upwind and downwind of the potential emission areas during the campaign. By taking into account measurement and sampling uncertainties and by determining the sensitivity of the measured mixing ratios to potential oceanic emissions, we provide upper limits for the CH4 fluxes. The CH4 flux during the campaign was small, with an upper limit of 2.5 nmol m−2 s−1 in the stability model scenario. The Zeppelin Observatory data for 2014 suggest CH4 fluxes from the Svalbard continental platform below 0.2 Tg yr−1. All estimates are in the lower range of values previously reported. PMID:28261536

  10. Constraints on oceanic methane emissions west of Svalbard from atmospheric in situ measurements and Lagrangian transport modeling

    NASA Astrophysics Data System (ADS)

    Pisso, I.; Myhre, C. Lund; Platt, S. M.; Eckhardt, S.; Hermansen, O.; Schmidbauer, N.; Mienert, J.; Vadakkepuliyambatta, S.; Bauguitte, S.; Pitt, J.; Allen, G.; Bower, K. N.; O'Shea, S.; Gallagher, M. W.; Percival, C. J.; Pyle, J.; Cain, M.; Stohl, A.

    2016-12-01

    Methane stored in seabed reservoirs such as methane hydrates can reach the atmosphere in the form of bubbles or dissolved in water. Hydrates could destabilize with rising temperature further increasing greenhouse gas emissions in a warming climate. To assess the impact of oceanic emissions from the area west of Svalbard, where methane hydrates are abundant, we used measurements collected with a research aircraft (Facility for Airborne Atmospheric Measurements) and a ship (Helmer Hansen) during the Summer 2014 and for Zeppelin Observatory for the full year. We present a model-supported analysis of the atmospheric CH4 mixing ratios measured by the different platforms. To address uncertainty about where CH4 emissions actually occur, we explored three scenarios: areas with known seeps, a hydrate stability model, and an ocean depth criterion. We then used a budget analysis and a Lagrangian particle dispersion model to compare measurements taken upwind and downwind of the potential CH4 emission areas. We found small differences between the CH4 mixing ratios measured upwind and downwind of the potential emission areas during the campaign. By taking into account measurement and sampling uncertainties and by determining the sensitivity of the measured mixing ratios to potential oceanic emissions, we provide upper limits for the CH4 fluxes. The CH4 flux during the campaign was small, with an upper limit of 2.5 nmol m-2 s-1 in the stability model scenario. The Zeppelin Observatory data for 2014 suggest CH4 fluxes from the Svalbard continental platform below 0.2 Tg yr-1. All estimates are in the lower range of values previously reported.

  11. Constraints on oceanic methane emissions west of Svalbard from atmospheric in situ measurements and Lagrangian transport modeling.

    PubMed

    Pisso, I; Myhre, C Lund; Platt, S M; Eckhardt, S; Hermansen, O; Schmidbauer, N; Mienert, J; Vadakkepuliyambatta, S; Bauguitte, S; Pitt, J; Allen, G; Bower, K N; O'Shea, S; Gallagher, M W; Percival, C J; Pyle, J; Cain, M; Stohl, A

    2016-12-16

    Methane stored in seabed reservoirs such as methane hydrates can reach the atmosphere in the form of bubbles or dissolved in water. Hydrates could destabilize with rising temperature further increasing greenhouse gas emissions in a warming climate. To assess the impact of oceanic emissions from the area west of Svalbard, where methane hydrates are abundant, we used measurements collected with a research aircraft (Facility for Airborne Atmospheric Measurements) and a ship (Helmer Hansen) during the Summer 2014 and for Zeppelin Observatory for the full year. We present a model-supported analysis of the atmospheric CH4 mixing ratios measured by the different platforms. To address uncertainty about where CH4 emissions actually occur, we explored three scenarios: areas with known seeps, a hydrate stability model, and an ocean depth criterion. We then used a budget analysis and a Lagrangian particle dispersion model to compare measurements taken upwind and downwind of the potential CH4 emission areas. We found small differences between the CH4 mixing ratios measured upwind and downwind of the potential emission areas during the campaign. By taking into account measurement and sampling uncertainties and by determining the sensitivity of the measured mixing ratios to potential oceanic emissions, we provide upper limits for the CH4 fluxes. The CH4 flux during the campaign was small, with an upper limit of 2.5 nmol m(-2) s(-1) in the stability model scenario. The Zeppelin Observatory data for 2014 suggest CH4 fluxes from the Svalbard continental platform below 0.2 Tg yr(-1). All estimates are in the lower range of values previously reported.

  12. Wintertime Methane and Non-Methane Hydrocarbon Measurements Utah's Uintah Basin

    NASA Astrophysics Data System (ADS)

    Martin, R. S.

    2012-12-01

    As a part of the winter 2011/2012 Uintah Basin Winter Ozone Study, ambient methane (CH4) and total non-methane hydrocarbons (TNMHC) were measured at a population center (Roosevelt) and within the oil/gas field (Horse Pool). At Horse Pool, near real-time CH4/TNMHC were monitored using a GC-FID analyzer. Samples were collected for 30 seconds once every five minutes. The TNMHC concentrations were reported in ppb-C3, or parts per billion in C3 (propane) equivalents. At Roosevelt, discrete volatile organic carbon (VOC) samples were collected for two weeks beginning on Feb. 14, 2012 using evacuated stainless steel Summa canisters. The samples were collected over four 1-hr time periods spaced throughout the day. After collection, the canisters were shipped to a commercial laboratory for GC-MS quantification. Methane samples were obtained at Roosevelt by whole vial collection and subsequently analyzed via GC-FID. Nominally, the CH4 vials were collected at the start and end of each canister collection period, as well as intermittently throughout the daily periods. Furthermore, CH4 grab samples were collected at several other locations throughout the Basin when possible. For the full wintertime study period (Jan. 19 - Mar. 15, 2012), the CH4 and TNMHC at Horse Pool averaged 3.47±1.8 ppm and 243±253 ppb-C3 (± 1σ), respectively. A very strong diurnal behavior was seen for both classes of compounds, with CH4 maximums approaching 30 ppm in the early morning hours. During the comparative February time period, CH4 concentrations at Horse Pool averaged 3.25±0.07 ppm (± 95% CI), while CH4 at Roosevelt averaged 2.52±0.08 ppm. No strong diurnal behavior was observed at Roosevelt and the maximum CH4 levels only reached 4.08 ppm. Grab samples from the other locations found similar or slightly lower CH4 concentrations, with the exception of Ouray (3.91±1.27 ppm) which was also located in the production/exploration area, but was among the lowest elevation of the sampling sites. It

  13. Daytime Chamber Measurements Miss Substantial Nighttime Methane Spikes Captured by Flux Tower

    NASA Astrophysics Data System (ADS)

    Godwin, C. M.; Markfort, C. D.; McNamara, P.

    2011-12-01

    Methane emissions from natural wetlands are estimated to range from 105 to 278 Tg per year, making wetlands the Earth's largest natural source of methane to the atmosphere. It is well established that methane production from a wetland varies spatially and temporally with parameters such as topography, soil temperature, and soil moisture content. Numerous studies on methane emission from wetlands have been performed using static chamber measurements. While this method measures methane emission directly from a known location, it may not capture spatial heterogeneity for the landscape of interest and the choice of chamber locations may lead to non-representative estimates of methane emissions. Furthermore, these emission estimates are limited in their temporal resolution due to the amount of time required to install and sample the chambers. Few studies have compared, from a wetland, both static chamber methane measurements and continuous measurements from a flux tower. In this work we analyzed methane emissions based on both techniques using data from the 1996 BOREAS project. The mean daytime methane emission rate from chamber measurements was greater than the mean from the tower, which suggests that a small number of chambers may be inadequate to describe spatial heterogeneity. Surprisingly, the nighttime methane emissions, measured with the flux tower, were often an order of magnitude greater than emissions recorded during the day by either method. Thus, the use of only daytime measurements would lead to a substantial underestimation of total methane emissions from the wetland. We will evaluate several potential explanations for heightened nighttime emissions and evaluate how this affects our efforts to reconcile static chamber measurements with ecosystem-wide estimates based on tower methods.

  14. Sources of atmospheric methane - Measurements in rice paddies and a discussion

    NASA Technical Reports Server (NTRS)

    Cicerone, R. J.; Shetter, J. D.

    1981-01-01

    Field measurements of methane fluxes from rice paddies, fresh water lakes, and saltwater marshes have been made to infer estimates of the size of these sources of atmospheric methane. The rice-paddy measurements, the first of their kind, show that the principal means of methane escape is through the plants themselves as opposed to transport across the water-air interface via bubbles or molecular diffusion. Nitrogen-fertilized plants release much more methane than unfertilized plants but even these measured rates are only one fourth as large as those inferred earlier by Koyama (1963, 1964) and on which all global extrapolations have been based to date. Measured methane fluxes from lakes and marshes are also compared to similar earlier data and it is found that extant data and flux-measurement methods are insufficient for reliable global extrapolations.

  15. Development of a Flight Instrument for in situ Measurements of Ethane and Methane

    NASA Astrophysics Data System (ADS)

    Wilkerson, J. P.; Sayres, D. S.; Anderson, J. G.

    2015-12-01

    Methane emissions data for natural gas and oil fields have high uncertainty. Better quantifying these emissions is crucial to establish an accurate methane budget for the United States. One obstacle is that these emissions often occur in areas near livestock facilities where biogenic methane abounds. Measuring ethane, which has no biogenic source, along with methane can tease these sources apart. However, ethane is typically measured by taking whole-air samples. This tactic has lower spatial resolution than making in situ measurements and requires the measurer to anticipate the location of emission plumes. This leaves unexpected plumes uncharacterized. Using Re-injection Mirror Integrated Cavity Output Spectroscopy (RIM-ICOS), we can measure both methane and ethane in flight, allowing us to establish more accurate fugitive emissions data that can more readily distinguish between different sources of this greenhouse gas.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. Direct measurements of methane emissions from abandoned oil and gas wells in Pennsylvania

    PubMed Central

    Kang, Mary; Kanno, Cynthia M.; Reid, Matthew C.; Zhang, Xin; Mauzerall, Denise L.; Celia, Michael A.; Chen, Yuheng; Onstott, Tullis C.

    2014-01-01

    Abandoned oil and gas wells provide a potential pathway for subsurface migration and emissions of methane and other fluids to the atmosphere. Little is known about methane fluxes from the millions of abandoned wells that exist in the United States. Here, we report direct measurements of methane fluxes from abandoned oil and gas wells in Pennsylvania, using static flux chambers. A total of 42 and 52 direct measurements were made at wells and at locations near the wells (“controls”) in forested, wetland, grassland, and river areas in July, August, October 2013 and January 2014, respectively. The mean methane flow rates at these well locations were 0.27 kg/d/well, and the mean methane flow rate at the control locations was 4.5 × 10−6 kg/d/location. Three out of the 19 measured wells were high emitters that had methane flow rates that were three orders of magnitude larger than the median flow rate of 1.3 × 10−3 kg/d/well. Assuming the mean flow rate found here is representative of all abandoned wells in Pennsylvania, we scaled the methane emissions to be 4–7% of estimated total anthropogenic methane emissions in Pennsylvania. The presence of ethane, propane, and n-butane, along with the methane isotopic composition, indicate that the emitted methane is predominantly of thermogenic origin. These measurements show that methane emissions from abandoned oil and gas wells can be significant. The research required to quantify these emissions nationally should be undertaken so they can be accurately described and included in greenhouse gas emissions inventories. PMID:25489074

  4. Direct measurements of methane emissions from abandoned oil and gas wells in Pennsylvania.

    PubMed

    Kang, Mary; Kanno, Cynthia M; Reid, Matthew C; Zhang, Xin; Mauzerall, Denise L; Celia, Michael A; Chen, Yuheng; Onstott, Tullis C

    2014-12-23

    Abandoned oil and gas wells provide a potential pathway for subsurface migration and emissions of methane and other fluids to the atmosphere. Little is known about methane fluxes from the millions of abandoned wells that exist in the United States. Here, we report direct measurements of methane fluxes from abandoned oil and gas wells in Pennsylvania, using static flux chambers. A total of 42 and 52 direct measurements were made at wells and at locations near the wells ("controls") in forested, wetland, grassland, and river areas in July, August, October 2013 and January 2014, respectively. The mean methane flow rates at these well locations were 0.27 kg/d/well, and the mean methane flow rate at the control locations was 4.5 × 10(-6) kg/d/location. Three out of the 19 measured wells were high emitters that had methane flow rates that were three orders of magnitude larger than the median flow rate of 1.3 × 10(-3) kg/d/well. Assuming the mean flow rate found here is representative of all abandoned wells in Pennsylvania, we scaled the methane emissions to be 4-7% of estimated total anthropogenic methane emissions in Pennsylvania. The presence of ethane, propane, and n-butane, along with the methane isotopic composition, indicate that the emitted methane is predominantly of thermogenic origin. These measurements show that methane emissions from abandoned oil and gas wells can be significant. The research required to quantify these emissions nationally should be undertaken so they can be accurately described and included in greenhouse gas emissions inventories.

  5. 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.

  6. Measuring Ebullition of Methane in a Temperate Wetland

    NASA Astrophysics Data System (ADS)

    Roddy, S.; Varner, R. K.; Palace, M. W.; Amante, J.; Yelverton, C.

    2013-12-01

    Methane (CH4) is a potent greenhouse gas, with wetlands being the main natural source of CH4 to the atmosphere. Ebullition, or bubbling is one pathway of CH4 emission to the atmosphere in wetland ecosystems. Rates of ebullition vary spatially and temporally according to dominant vegetation type, peat density and time of year or season. We studied the continuous and episodic nature of ebullition and how it varies with species composition using six acoustic and manual sensors deployed in a temperate wetland, Sallie's Fen, Barrington, NH in Fall 2011. These sensors recorded continuously from June through October in each year. From these sensors, manual collections of accumulated gas were sampled to measure both the volume of gas and concentration of CH4. To identify differences in ebullition rates due to varying species composition, we installed six additional sensors in June 2013. Peat temperature and water table depth were also recorded both manually and continuously over these periods. Measured ebullitive fluxes ranged from 0 to 419 mg/m2/day. Acoustic data shows relationships between water table height and changes in other environmental variables. A subsample of the manual bubble collections at each sensor will be analyzed for 13C-CH4 and CH3D to help us understand the dominant methanogenic pathway and how this may vary with species composition and season.

  7. 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

  8. In situ measurement of methane oxidation in groundwater by using natural-gradient tracer tests

    USGS Publications Warehouse

    Smith, R.L.; Howes, B.L.; Garabedian, S.P.

    1991-01-01

    Methane oxidation was measured in an unconfined sand and gravel aquifer (Cape Cod, Mass.) by using in situ natural-gradient tracer tests at both a pristine, oxygenated site and an anoxic, sewage-contaminated site. The tracer sites were equipped with multilevel sampling devices to create target grids of sampling points; the injectate was prepared with groundwater from the tracer site to maintain the same geochemical conditions. Methane oxidation was calculated from breakthrough curves of methane relative to halide and inert gas (hexafluoroethane) tracers and was confirmed by the appearance of 13C-enriched carbon dioxide in experiments in which 13C-enriched methane was used as the tracer. A V(max) for methane oxidation could be calculated when the methane concentration was sufficiently high to result in zero-order kinetics throughout the entire transport interval. Methane breakthrough curves could be simulated by modifying a one-dimensional advection-dispersion transport model to include a Michaelis-Menten-based consumption term for methane oxidation. The K(m) values for methane oxidation that gave the best match for the breakthrough curve peaks were 6.0 and 9.0 ??M for the uncontaminated and contaminated sites, respectively. Natural-gradient tracer tests are a promising approach for assessing microbial processes and for testing in situ bioremediation potential in groundwater systems.

  9. Method for Determining the Coalbed Methane Content with Determination the Uncertainty of Measurements

    NASA Astrophysics Data System (ADS)

    Szlązak, Nikodem; Korzec, Marek

    2016-06-01

    Methane has a bad influence on safety in underground mines as it is emitted to the air during mining works. Appropriate identification of methane hazard is essential to determining methane hazard prevention methods, ventilation systems and methane drainage systems. Methane hazard is identified while roadways are driven and boreholes are drilled. Coalbed methane content is one of the parameters which is used to assess this threat. This is a requirement according to the Decree of the Minister of Economy dated 28 June 2002 on work safety and hygiene, operation and special firefighting protection in underground mines. For this purpose a new method for determining coalbed methane content in underground coal mines has been developed. This method consists of two stages - collecting samples in a mine and testing the sample in the laboratory. The stage of determining methane content in a coal sample in a laboratory is essential. This article presents the estimation of measurement uncertainty of determining methane content in a coal sample according to this methodology.

  10. 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.

  11. Laboratory measurements of compressional and shear wave speeds through methane hydrate

    USGS Publications Warehouse

    Waite, W.F.; Helgerud, M.B.; Nur, A.; Pinkston, J.C.; Stern, L.A.; Kirby, S.H.; Durham, W.B.

    2000-01-01

    Simultaneous measurements of compressional and shear wave speeds through polycrystalline methane hydrate have been made. Methane hydrate, grown directly in a wave speed measurement chamber, was uniaxially compacted to a final porosity below 2%. At 277 K, the compacted material had a compressional wave speed of 3650 ?? 50 m/s. The shear wave speed, measured simultaneously, was 1890 ?? 30 m/s. From these wave speed measurements, we derive V(p)/V(s), Poisson's ratio, bulk, shear, and Young's moduli.

  12. 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.

  13. 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.

  14. 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.

  15. River methane hot-spots: Continuous methane ebullition measurements over an annual cycle linked to river sediment production

    NASA Astrophysics Data System (ADS)

    Wilkinson, Jeremy; Maeck, Andreas; Ashboul, Zeyad; Lorke, Andreas

    2015-04-01

    Hot spot methane ebullition from impounded river reaches matches high rates observed around the globe. Ebullition dominates total methane flux in the Saar River (Germany) and is largely determined by sediment deposition rate. Using automated bubble traps developed in-house, and deployed over a year at four sites, we collected high resolution data showing that hydrodynamic disturbances from shipping, lock operations and hydrograph events trigger ebullition episodes. Reverse smoothing was used to integrate the observed ebullition back in time, and helped in visualizing the data, and provides a time-series closer to methane accumulation in the sediments, whereas ebullition shows the triggering and release of the accumulated gas. One major hydrological disturbance of shallow-water sediment released around 13% of the total annual ebullition at that site, and ebullition generally followed the seasonal sediment temperature variations. The same event damped ebullition from deeper water sites. Total annual ebullition values ranged from 200 to 500 gCH4 m-2 yr-1. Ebullition from shallow water sediments in winter ceased for extended periods, but continued un-broken from deeper sites. With on-going measurements we believe these findings will help to improve estimates and the modelling of methane emissions from impounded river systems.

  16. A multitower measurement network estimate of California's methane emissions

    NASA Astrophysics Data System (ADS)

    Jeong, Seongeun; Hsu, Ying-Kuang; Andrews, Arlyn E.; Bianco, Laura; Vaca, Patrick; Wilczak, James M.; Fischer, Marc L.

    2013-10-01

    present an analysis of methane (CH4) emissions using atmospheric observations from five sites in California's Central Valley across different seasons (September 2010 to June 2011). CH4 emissions for spatial regions and source sectors are estimated by comparing measured CH4 mixing ratios with transport model (Weather Research and Forecasting and Stochastic Time-Inverted Lagrangian Transport) predictions based on two 0.1° CH4 (seasonally varying "California-specific" (California Greenhouse Gas Emission Measurements, CALGEM) and a static global (Emission Database for Global Atmospheric Research, release version 42, EDGAR42)) prior emission models. Region-specific Bayesian analyses indicate that for California's Central Valley, the CALGEM- and EDGAR42-based inversions provide consistent annual total CH4 emissions (32.87 ± 2.09 versus 31.60 ± 2.17 Tg CO2eq yr-1; 68% confidence interval (CI), assuming uncorrelated errors between regions). Summing across all regions of California, optimized CH4 emissions are only marginally consistent between CALGEM- and EDGAR42-based inversions (48.35 ± 6.47 versus 64.97 ± 11.85 Tg CO2eq), because emissions from coastal urban regions (where landfill and natural gas emissions are much higher in EDGAR than CALGEM) are not strongly constrained by the measurements. Combining our results with those from a recent study of the South Coast Air Basin narrows the range of estimates to 43-57 Tg CO2eq yr-1 (1.3-1.8 times higher than the current state inventory). These results suggest that the combination of rural and urban measurements will be necessary to verify future changes in California's total CH4 emissions.

  17. A multitower measurement network estimate of California's methane emissions

    SciTech Connect

    Jeong, Seongeun; Hsu, Ying-Kuang; Andrews, Arlyn E.; Bianco, Laura; Vaca, Patrick; Wilczak, James M.; Fischer, Marc L.

    2013-09-20

    In this paper, we present an analysis of methane (CH4) emissions using atmospheric observations from five sites in California's Central Valley across different seasons (September 2010 to June 2011). CH4 emissions for spatial regions and source sectors are estimated by comparing measured CH4 mixing ratios with transport model (Weather Research and Forecasting and Stochastic Time-Inverted Lagrangian Transport) predictions based on two 0.1° CH4 (seasonally varying “California-specific” (California Greenhouse Gas Emission Measurements, CALGEM) and a static global (Emission Database for Global Atmospheric Research, release version 42, EDGAR42)) prior emission models. Region-specific Bayesian analyses indicate that for California's Central Valley, the CALGEM- and EDGAR42-based inversions provide consistent annual total CH4 emissions (32.87 ± 2.09 versus 31.60 ± 2.17 Tg CO2eq yr-1; 68% confidence interval (CI), assuming uncorrelated errors between regions). Summing across all regions of California, optimized CH4 emissions are only marginally consistent between CALGEM- and EDGAR42-based inversions (48.35 ± 6.47 versus 64.97 ± 11.85 Tg CO2eq), because emissions from coastal urban regions (where landfill and natural gas emissions are much higher in EDGAR than CALGEM) are not strongly constrained by the measurements. Combining our results with those from a recent study of the South Coast Air Basin narrows the range of estimates to 43–57 Tg CO2eq yr-1 (1.3–1.8 times higher than the current state inventory). Finally, these results suggest that the combination of rural and urban measurements will be necessary to verify future changes in California's total CH4 emissions.

  18. Methane emissions from termites - landscape level estimates and methods of measurement

    NASA Astrophysics Data System (ADS)

    Jamali, Hizbullah; Livesley, Stephen J.; Hutley, Lindsay B.; Arndt, Stefan K.

    2013-04-01

    Termites contribute between <5 and 19% of the global methane emissions. These estimates have large uncertainties because of the limited number of field-based studies and species investgated, as well as issues of diurnal and seasonal variations. We measured methane fluxes from four common mound-building termite species diurnally and seasonally in tropical savannas in the Northern Territory, Australia. Our results showed that there were significant diel and seasonal variations of methane emissions from termite mounds and we observed large species-specific differences. On a diurnal basis, methane fluxes were least at the coolest time of the day and greatest at the warmest for all species for both wet and dry seasons. We observed a strong and significant positive correlation between methane flux and mound temperature for all species. Fluxes in the wet season were 5-26-fold greater than those in the dry season and this was related to population dynamics of the termites. We observed significant relationships between mound methane flux and mound carbon dioxide flux, enabling the prediction of methane flux from measured carbon dioxide flux. However, these relationships were clearly termite species specific. We also determined significant relationships between mound flux and gas concentration inside mound, for both gases, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Consequently, there was no generic relationship that would enable an easier prediction of methane flux from termite mounds. On a landscape scale we estimated that termites were a methane source of +0.24 kg methane-C ha-1 year-1 whilst savanna soils were a methane sink of 1.14 kg methane-C ha-1 year-1. Termites therefore only offset 21% of methane consumed by savanna soil resulting in net sink strength of -0.90 kg methane-C ha-1 year-1 for these savannas. Assuming a similar

  19. A model-based data analysis of the atmospheric methane above Siberia during YAK-AEROSIB airborne campaign in summer 2012

    NASA Astrophysics Data System (ADS)

    Arzoumanian, Emmanuel; Paris, Jean-Daniel; Pruvost, Arnaud; Berchet, Antoine; Pison, Isabelle; Arshinov, Mikhail; Belan, Boris

    2014-05-01

    High latitude regions are large sources of CH4 in the atmosphere, both natural from boreal wetlands and wildfires, and anthropogenic from natural gas extraction industry, especially in the Russian Arctic. Our current understanding of the extent and amplitude of the natural sources, as well as the large scale driving factors, remain highly uncertain (Kirschke et al., Nature Geosci., 2013). After a decade of pause, atmospheric methane seems to be increasing again, with a possible significant contribution from the wetlands of the northern high latitudes initiated by an unusual rise of regional temperatures in 2007 (Dlugokencky et al., 2009). This work aims at better understanding high latitude CH4 sources and sinks using atmospheric measurements and transport model. YAK-AEROSIB atmospheric airborne campaigns have been performed in order to provide observational data about the composition of Siberian air. In this work, we focus on the 2012 campaign which has been conducted on July 31st and August 1st. It consisted of five flights, performed in the troposphere from the boundary layer up to 8.5 km, connecting Novosibirsk to Yakutsk and back. This particular campaign was dominated by wildfires in Western and central Siberia. Therefore a chemistry-transport model (CHIMERE), combined with datasets for anthropogenic (EDGAR) emissions and models for wetlands (ORCHIDEE) and wildfire (GFED), has been used to interpret the collected data. From tagged tracers and model observation mismatch we describe results concerning CH4 fluxes in the Siberian territory. This work was funded by CNRS (France), the French Ministry of Foreign Affairs, CEA (France), Presidium of RAS (Program No. 4), Brunch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5), Interdisciplinary integration projects of Siberian Branch of RAS (No. 35, No. 70, No. 131), Russian Foundation for Basic Research (grants No 14-05-00526, 14-05-00590). Kirschke, S., P. Bousquet, P. Ciais, M. Saunois, J

  20. 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.

  1. Ground and aircraft-based methane measurements in Siberia: source attribution using tracers and models

    NASA Astrophysics Data System (ADS)

    Arzoumanian, E.; Paris, J. D.; Pruvost, A.; Peng, S.; Turquety, S.; Berchet, A.; Pison, I.; Helle, J.; Arshinov, M.; Belan, B. D.

    2015-12-01

    Methane (CH4) is the second most important anthropogenic greenhouse gas. It is also naturally emitted by a number of processes, including microbial activity in wetlands, permafrost degradation and wildfires. Our current understanding of the extent and amplitude of its natural sources, as well as the large scale driving factors, remain highly uncertain (Kirschke et al., Nature Geosci., 2013). Furthermore, high latitude regions are large natural sources of CH4 in the atmosphere. Observing boreal/Arctic CH4 variability and understanding its main driving processes using atmospheric measurements and transport model is the task of this work. YAK-AEROSIB atmospheric airborne campaigns (flights in the tropospheric layer up to 9 km connecting the two cities of Novosibirsk and Yakutsk) and continuous measurements at Fonovaya Observatory (60 km west of Tomsk - 56° 25'07"N, 84° 04'27"E) have been performed in order to provide observational data on the composition of Siberian air. The study is focused on 2012, during which a strong heat wave impacted Siberia, leading to the highest mean daily temperature values on record since the beginning of the 20th century. This abnormal drought has led to numerous large forest fires. A chemistry-transport model (CHIMERE), combined with datasets for anthropogenic (EDGAR) emissions and models for wetlands (ORCHIDEE) and wildfires (APIFLAME), is used to determine contributions of CH4 sources in the region. Recent results concerning CH4 fluxes and its atmospheric variability in the Siberian territory derived from a modeled-based analysis will be shown and discussed. This work was funded by CNRS (France), the French Ministry of Foreign Affairs, CEA (France), Presidium of RAS (Program No. 4), Brunch of Geology, Geophysics and Mining Sciences of RAS (Program No. 5), Interdisciplinary integration projects of Siberian Branch of RAS (No. 35, No. 70, No. 131), Russian Foundation for Basic Research (grants No 14-05-00526, 14-05-00590). Kirschke, S

  2. High Time Resolution Measurements of Methane Fluxes From Enteric Fermentation in Cattle Rumen

    NASA Astrophysics Data System (ADS)

    Floerchinger, C. R.; Herndon, S.; Fortner, E.; Roscioli, J. R.; Kolb, C. E.; Knighton, W. B.; Molina, L. T.; Zavala, M.; Castelán, O.; Ku Vera, J.; Castillo, E.

    2013-12-01

    Methane accounts for roughly 20% of the global radiative climate forcing in the last two and a half centuries. Methane emissions arise from a number of anthropogenic and biogenic sources. In some areas enteric fermentation in livestock produces over 90% of agricultural methane. In the spring of 2013, as a part of the Short Lived Climate Forcer-Mexico field campaign, the Aerodyne Mobile Laboratory in partnership with the Molina Center for the Environment studied methane production associated with enteric fermentation in the rumen of cattle. A variety of different breeds and stocks being raised in two agricultural and veterinary research facilities located in different areas of Mexico were examined. Methane fluxes were quantified using two methods: 1) an atmospherically stable gaseous tracer release was collocated with small herds in a pasture, allowing tracer ratio flux measurements; 2) respiratory CO2 was measured in tandem with methane in the breath of individual animals allowing methane production to be related to metabolism. The use of an extensive suite of very high time response instruments allows for differentiation of individual methane producing rumination events and respiratory CO2 from possible background interferences. The results of these studies will be presented and compared to data from traditional chamber experiments.

  3. Stable isotope and high precision concentration measurements confirm that all humans produce and exhale methane.

    PubMed

    Keppler, Frank; Schiller, Amanda; Ehehalt, Robert; Greule, Markus; Hartmann, Jan; Polag, Daniela

    2016-01-29

    Mammalian formation of methane (methanogenesis) is widely considered to occur exclusively by anaerobic microbial activity in the gastrointestinal tract. Approximately one third of humans, depending on colonization of the gut by methanogenic archaea, are considered methane producers based on the classification terminology of high and low emitters. In this study laser absorption spectroscopy was used to precisely measure concentrations and stable carbon isotope signatures of exhaled methane in breath samples from 112 volunteers with an age range from 1 to 80 years. Here we provide analytical evidence that volunteers exhaled methane levels were significantly above background (inhaled) air. Furthermore, stable carbon isotope values of the exhaled methane unambiguously confirmed that this gas was produced by all of the human subjects studied. Based on the emission and stable carbon isotope patterns of various age groups we hypothesize that next to microbial sources in the gastrointestinal tracts there might be other, as yet unidentified, processes involved in methane formation supporting the idea that humans might also produce methane endogenously in cells. Finally we suggest that stable isotope measurements of volatile organic compounds such as methane might become a useful tool in future medical research diagnostic programs.

  4. 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.

  5. 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.

  6. 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).

  7. 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.

  8. 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.

  9. Estimating daily methane production in individual cattle with irregular feed intake patterns from short-term methane emission measurements.

    PubMed

    Cottle, D J; Velazco, J; Hegarty, R S; Mayer, D G

    2015-12-01

    Spot measurements of methane emission rate (n = 18 700) by 24 Angus steers fed mixed rations from GrowSafe feeders were made over 3- to 6-min periods by a GreenFeed emission monitoring (GEM) unit. The data were analysed to estimate daily methane production (DMP; g/day) and derived methane yield (MY; g/kg dry matter intake (DMI)). A one-compartment dose model of spot emission rate v. time since the preceding meal was compared with the models of Wood (1967) and Dijkstra et al. (1997) and the average of spot measures. Fitted values for DMP were calculated from the area under the curves. Two methods of relating methane and feed intakes were then studied: the classical calculation of MY as DMP/DMI (kg/day); and a novel method of estimating DMP from time and size of preceding meals using either the data for only the two meals preceding a spot measurement, or all meals for 3 days prior. Two approaches were also used to estimate DMP from spot measurements: fitting of splines on a 'per-animal per-day' basis and an alternate approach of modelling DMP after each feed event by least squares (using Solver), summing (for each animal) the contributions from each feed event by best-fitting a one-compartment model. Time since the preceding meal was of limited value in estimating DMP. Even when the meal sizes and time intervals between a spot measurement and all feeding events in the previous 72 h were assessed, only 16.9% of the variance in spot emission rate measured by GEM was explained by this feeding information. While using the preceding meal alone gave a biased (underestimate) of DMP, allowing for a longer feed history removed this bias. A power analysis taking into account the sources of variation in DMP indicated that to obtain an estimate of DMP with a 95% confidence interval within 5% of the observed 64 days mean of spot measures would require 40 animals measured over 45 days (two spot measurements per day) or 30 animals measured over 55 days. These numbers suggest that

  10. Estimates of Methane and Ethane Emissions from the Barnett Shale Using Atmospheric Measurements

    NASA Astrophysics Data System (ADS)

    Karion, A.; Sweeney, C.; Kort, E. A.; Shepson, P. B.; Conley, S. A.; Lauvaux, T.; Davis, K. J.; Deng, A.; Lyon, D. R.; Smith, M. L.

    2015-12-01

    Recent development of horizontal drilling technology and advances in hydraulic fracturing techniques by the oil and gas industry have dramatically increased onshore U.S. natural gas and oil production in the last several years. The primary component of natural gas is methane (CH4), a powerful greenhouse gas; therefore, natural gas leakage into the atmosphere affects its climate impact. We present estimates of regional methane (CH4) and ethane (C2H6) emissions from oil and natural gas operations in the Barnett Shale, Texas, made in March and October 2013 as part of the Environmental Defense Fund's Barnett Coordinated Campaign. The Barnett is one of the largest production basins in the United States, with 8% of total U.S. natural gas production, and thus, our results represent a crucial step toward determining the greenhouse gas footprint of U.S. onshore natural gas production. Using a mass balance approach on eight different flight days the total CH4 emissions for the region are estimated to be 76 ± 13x 103 kg/hr, or 0.66 ± 0.11 Tg CH4 /yr; (95% CI). Repeated mass balance flights in the same basin on eight different days and two seasons demonstrate the consistency of the mass balance approach. On the basis of airborne C2H6 and CH4 measurements, we find 71-85% of the observed CH4 emissions quantified in the Barnett Shale are derived from fossil sources. The average C2H6 flux was 6.6 ± 0.2 x 103 kg/hr and consistent across six days in spring and fall of 2013. This result is the first demonstration of this approach for C2H6. We estimate that 60±11x103 kg CH4/hr (95% CI) are emitted by natural gas and oil operations, including production, processing, and distribution in the urban areas of Dallas and Fort Worth. This estimate is significantly higher than emissions reported by the EDGAR inventory or by industry to EPA's Greenhouse Gas Reporting Program.

  11. 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.

  12. Controls on gas hydrate stability in methane depleted sediments: Laboratory and field measurements

    NASA Astrophysics Data System (ADS)

    Lapham, L.; Chanton, J.; Martens, C. S.

    2009-12-01

    Gas hydrate deposits are the Earth’s largest reservoir of the powerful greenhouse gas methane and thus a key future energy resource. However, hydrate stability in sedimentary environments featuring highly variable methane concentrations needs to be understood to allow resource estimation and recovery. Hydrates are at chemical equilibrium and therefore stable where high pressures, low temperatures, and moderate salinities coexist with methane-saturated pore waters. When all of these conditions are not met, hydrates should dissociate or dissolve, releasing methane to the overlying water and possibly the atmosphere. In addition, other natural factors may control the kinetics of their degradation complicating models for hydrate stability and occurrence. Our measurements indicate that the pore-waters surrounding some shallow buried hydrates are not methane-saturated suggesting that dissolution should occur relatively rapidly. Yet, these hydrate deposits are known to persist relatively unchanged for years. We hypothesize that, once formed, hydrate deposits may be stabilized by natural factors inhibiting dissolution, including oil or microbial biofilm coatings. While most studies have focused on pressure and temperature changes where hydrates occur, relatively few have included measurements of in situ methane concentration gradients because of the difficulties inherent to making such measurements. Here we present recent measurements of methane concentration and stable carbon isotope gradients immediately adjacent to undisturbed hydrate surfaces obtained through deployments of novel seafloor instruments. Our results suggest that the hydrates studied are relatively stable when exposed to overlying and pore-waters that are undersaturated with methane. Concurrent laboratory measurements of methane concentration gradients next to artificial hydrate surfaces were utilized to test our protective coating hypothesis. After a stable dissolution rate for hydrate samples was

  13. 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.

  14. 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.

  15. 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.

  16. Biomass measurement of methane forming bacteria in environmental samples

    NASA Technical Reports Server (NTRS)

    Martz, R. F.; Sebacher, D. I.; White, D. C.

    1983-01-01

    Methane-forming bacteria contain unusual phytanylglycerol ether phospholipids which can be extracted from the bacteria in sediments and assayed quantitatively by high performance liquid chromatography (HPLC). In this procedure the lipids were extracted, the phospholipids recovered, hydrolyzed, purified by thin layer chromatography, derivatized and assayed by HPLC. Ether lipids were recovered quantitatively from Methanobacterium thermoautotrophicum and sediments at levels as low as 8 x 10(-14) moles. In freshwater and marine sediments the flux of methane to the atmosphere and the methane levels in the pore water reflects the recovery of the phytanyl glycerol ether lipid 'signature'. The proportion of the ether phospholipid to the total recoverable phospholipid was highest in anaerobic digester sewage sludge and deeper subsurface freshwater sediment horizons.

  17. Area-Based Measurements of Methane Emissions from Oil and Natural Gas Operations- September 2012 Workshop

    EPA Pesticide Factsheets

    View a presentation on area-based measurements of methane (CH4) emissions, presented at the Stakeholder Workshop on Natural Gas in the Inventory of U.S. Greenhouse Gas (GHG) Emissions and Sinks on Thursday, September 13, 2012.

  18. Measurements of an Anomalous Global Methane Increase During 1998

    NASA Technical Reports Server (NTRS)

    Dlugokencky, E. J.; Walter, B. P.; Masarie, K. A.; Lang, P. M.; Kasischke, E. S.; Hansen, James E. (Technical Monitor)

    2001-01-01

    Measurements of atmospheric methane from a globally distributed network of air sampling sites indicate that the globally averaged CH4 growth rate increased from an average of 3.9 ppb/yr during 1995-1997 to 12.7 +/- 0.6 ppb in 1998. The global growth rate then decreased to 2.6 +/- 0.6 ppb during 1999, indicating that the large increase in 1998 was an anomaly and not a return to the larger growth rates observed during the late 1970s and early 1980s. The increased growth rate represents an anomalous increase in the imbalance between CH4 sources and sinks equal to approximately 24 Tg CH4 during 1998. Wetlands and boreal biomass burning are sources that may have contributed to the anomaly. During 1998, the globally averaged temperature anomaly was +0.67 C, the largest temperature anomaly in the modern record. A regression model based on temperature and precipitation anomalies was used to calculate emission anomalies of 11.6 Tg CH4 from wetlands north of 30 N and 13 Tg CH4 for tropical wetlands during 1998 compared to average emissions calculated for 1982-1993. In 1999, calculated wetland emission anomalies were negative for high northern latitudes and the tropics, contributing to the low growth rate observed in 1999. Also 1998 was a severe fire year in boreal regions where approximately 1.3x10(exp 5) sq km of forest and peat land burned releasing an estimated 5.7 Tg CH4

  19. Acoustic and manual measurements of methane ebullition in peatlands

    NASA Astrophysics Data System (ADS)

    Varner, R. K.; Palace, M. W.; Lennartz, J. M.; Wik, M.; Crill, P. M.; Ewing, S. A.; Harden, J. W.; Turetsky, M. R.

    2013-12-01

    Controls on the magnitude and frequency of methane (CH4) release through ebullition (bubbling) in water saturated ecosystems such as bogs, fens and lakes are important to both the atmospheric and ecosystems science community. In order to understand the response of these ecosystems to future climate forcing, we need to systematically monitor ebullition from these ecosystems over many seasons and across a multitude of landscape morphologies. We have developed and field tested an inexpensive array of sampling/monitoring instruments to identify the frequency and magnitude of bubbling events which allows us to correlate bubble data with potential drivers such as changes in hydrostatic pressure, wind and temperature. The instrument consists of a nested, inverted funnel design with a hydrophone for detecting bubbles that rise through the peat. The design offers a way to sample the gas collected in the funnels to determine the concentration of CH4. Laboratory calibration of the instrument resulted in an equation that relates frequency of bubbles hitting the hydrophone with bubble volume. Audio data was recorded continuously using a digital audio recorder attached to two ebullition sensors and could be deployed remotely for up to 20 days. Time, fundamental frequency, and estimated bubble size were determined using MATLAB code. Manual bubble flux measurements were also made for comparison to the acoustically sensed ebullition. Instruments were deployed in summers 2011-2013 at a temperate fen (Sallie's Fen, NH, USA) and a subarctic mire (Stordalen, Abisko, Sweden). We also recorded ebullition at two locations in subarctic Alaska (APEX Research Site, Fairbanks, AK and Innoko National Wildlife Refuge) during summer 2011. Ebullition was observed at all sites with highest daily rates in fen versus bog sites. Observed distributions of bubble events correlate with published models of ebullition based on peat density.

  20. 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.

  1. Methane emissions from a beef cattle feedyard: measurements and models

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methane (CH4) emissions from enteric fermentation by livestock account for about 2% of U.S. greenhouse gas (GHG) emissions, with beef and dairy cattle the most significant sources. Most current approaches to estimate the contribution of cattle to GHG emissions use emission factors based on productio...

  2. 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

  3. 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

  4. Fluxes of atmospheric methane using novel instruments, field measurements, and inverse modeling

    NASA Astrophysics Data System (ADS)

    Santoni, Gregory Winn

    The atmospheric concentration of methane (CH4) -- the most significant non-CO2 anthropogenic long-lived greenhouse gas -- stabilized between 1999 and 2006 and then began to rise again. Explanations for this behavior differ but studies agree that more measurements and better modeling are needed to reliably explain the model-data discrepancies and predict future change. This dissertation focuses on measurements of CH4 and inverse modeling of atmospheric CH4 fluxes using field measurements at a variety of spatial scales. We first present a new fast-response instrument to measure the isotopic composition of CH4 in ambient air. The instrument was used to characterize mass fluxes and isofluxes (a isotopically-weighted mass flux) from a well-studied research fen in New Hampshire. Eddycovariance and automatic chamber techniques produced consistent estimates of both the CH4 fluxes and their isotopic composition at sub-hourly resolution. We then characterize fluxes of CH4 from aircraft engines using measurements made with the same instrument during the Alternative Aviation Fuel Experiment (AAFEX), a study that aimed to determine the atmospheric impacts of alternative fuel use in the growing aviation industry. Emissions of CO2, CH4, and N2O from different synthetic fuels were statistically indistinguishable from those of the widely used JP-8 jet fuel. We then present airborne observations of the long-lived greenhouse gas suite -- CO2, CH4, N2O, and CO -- during two aircraft campaigns, HIPPO and CalNex, made using a similar instrument built specifically for the NCAR HIAPER GV aircraft. These measurements are compared to data from other onboard sensors and show excellent agreement. We discuss the details of the end-to-end calibration procedures and the data quality-assurance and qualitycontrol (QA/QC). Lastly, we quantify a top-down estimate of California's CH4 emission inventory using the CalNex CH4 observations. Observed CH4 enhancements above background concentrations are

  5. Measurement of the Isotopic Signatures of Water on Mars: Implications for Studying Methane

    NASA Technical Reports Server (NTRS)

    Novak, R. E.; Mumma, M. J.; Villanueva, G. L.

    2010-01-01

    The recent discovery of methane on Mars has led to much discussion concerning its origin. On Earth, the isotopic signatures of methane vary with the nature of its production. Specifically, the ratios among 12CH4, 13CH4, and 12CH3D differ for biotic and abiotic origins. On Mars, measuring these ratios would provide insights into the origins of methane and measurements of water isotopologues co-released with methane would assist in testing their chemical relationship. Since 1997, we have been measuring HDO and H2O in Mars atmosphere and comparing their ratio to that in Earth s oceans. We recently incorporated a line-by-line radiative transfer model (LBLRTM) into our analysis. Here, we present a map for [HDO]/[H2O] along the central meridian (1541W) for Ls 501. From these results, we constructed models to determine the observational conditions needed to quantify the isotopic ratios of methane in Mars atmosphere. Current ground-based instruments lack the spectral resolution and sensitivity needed to make these measurements. Measurements of the isotopologues of methane will likely require in situ sampling.

  6. 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.

  7. Direct Measure of the Dense Methane Phase in Gas Shale Organic Porosity by Neutron Scattering

    DOE PAGES

    Eberle, Aaron P. R.; King, Hubert E.; Ravikovitch, Peter I.; ...

    2016-08-30

    Here, we report the first direct measurements of methane density in shale gas using small-angle neutron scattering. At a constant pressure, the density of methane in the inorganic pores is similar to the gas bulk density of the system conditions. Conversely, the methane density is 2.1 ± 0.2 times greater in the organic mesopores. Furthermore, classical density functional theory calculations show that this excess density in the organic pores persists to elevated temperatures, typical of shale gas reservoir conditions, providing new insight into the hydrocarbon storage mechanisms within these reservoirs.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Using Integrated Cavity Output Spectroscopy (ICOS) for Aircraft Measurements of Methane Isotopologues

    NASA Astrophysics Data System (ADS)

    Wilkerson, J. P.; Sayres, D. S.; Healy, C. E.; Munster, J. B.; Dubey, M. K.; Anderson, J. G.

    2014-12-01

    Methane emissions in arctic regions have the potential to contribute a large positive radiative forcing to our climate structure. However, methane in the Arctic has multiple sources and sinks which can complicate source attribution and quantification attempts. In situ stable isotope measurements provide a way to help tease apart different methane sources since the two primary methane sources, thermogenic and biogenic, have distinct isotopic signatures. Ultimately, this knowledge about the ratio between 13CH4 and 12CH4 concentrations can help us understand the relative contribution from each source. The ICOS instrument developed in our lab is an ideal candidate to obtain this type of information. Unlike other measurement methods such as IRMS, our instrument has been tailored to fit in a small aircraft capable of flying below the boundary layer in the arctic region. We flew ICOS in Summer 2013 over the north slope of Alaska and obtained spatially (every 160 m) and temporally (every 2 s) resolved δ13CH4 measurements in real time. Future missions will entail a Stirling-cooled detector in the instrument to further enhance the precision and sensitivity of the measurements. These field missions will enhance our understanding of the routes by which methane is being produced in these regions. This improved knowledge can then lead to improved predictive ability regarding the characteristics of future methane flux and its effect on our climate.

  13. 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.

  14. 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.

  15. 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.

  16. Methane emissions from boreal and tropical forest ecosystems derived from in-situ measurements

    NASA Astrophysics Data System (ADS)

    Sinha, V.; Williams, J.; Crutzen, P. J.; Lelieveld, J.

    2007-09-01

    Methane is a climatologically important greenhouse gas, which plays a key role in regulating water vapour in the stratosphere and hydroxyl radicals in the troposphere. Recent findings that vegetation emits methane have stimulated efforts to ascertain the impact of this source on the global budget. In this work, we present the results of high frequency (ca. 1 min-1) methane measurements conducted in the boreal forests of Finland and the tropical forests of Suriname, in April-May, 2005 and October 2005 respectively. The measurements were performed using a gas chromatograph - flame ionization detector (GC-FID). The average of the median mixing ratios during a typical diel cycle were 1.83 μmol mol-1 and 1.74 μmol mol-1 for the boreal forest ecosystem and tropical forest ecosystem respectively, with remarkable similarity in the time series of both the boreal and tropical diel profiles. Night time methane emission flux of the boreal forest ecosystem, calculated from the increase of methane during the night and measured nocturnal boundary layer heights yields a flux of (3.62±0.87)×1011 molecules cm-2 s-1(or 45.5±11 Tg CH4 yr-1 for global boreal forest area). This is a source contribution of circa 8% of the global methane budget. These results highlight the importance of the boreal and tropical forest ecosystems for the global budget of methane. The results are also discussed in the context of recent work reporting high methane mixing ratios over tropical forests using space borne near infra-red spectroscopy measurements.

  17. Field intercomparison of four methane gas analyzers suitable for eddy covariance flux measurements

    NASA Astrophysics Data System (ADS)

    Peltola, O.; Mammarella, I.; Haapanala, S.; Burba, G.; Vesala, T.

    2013-06-01

    Performances of four methane gas analyzers suitable for eddy covariance measurements are assessed. The assessment and comparison was performed by analyzing eddy covariance data obtained during summer 2010 (1 April to 26 October) at a pristine fen, Siikaneva, Southern Finland. High methane fluxes with pronounced seasonality have been measured at this fen. The four participating methane gas analyzers are commercially available closed-path units TGA-100A (Campbell Scientific Inc., USA), RMT-200 (Los Gatos Research, USA), G1301-f (Picarro Inc., USA) and an early prototype open-path unit Prototype-7700 (LI-COR Biosciences, USA). The RMT-200 functioned most reliably throughout the measurement campaign, during low and high flux periods. Methane fluxes from RMT-200 and G1301-f had the smallest random errors and the fluxes agree remarkably well throughout the measurement campaign. Cospectra and power spectra calculated from RMT-200 and G1301-f data agree well with corresponding temperature spectra during a high flux period. None of the gas analyzers showed statistically significant diurnal variation for methane flux. Prototype-7700 functioned only for a short period of time, over one month, in the beginning of the measurement campaign during low flux period, and thus, its overall accuracy and season-long performance were not assessed. The open-path gas analyzer is a practical choice for measurement sites in remote locations due to its low power demand, whereas for G1301-f methane measurements interference from water vapor is straightforward to correct since the instrument measures both gases simultaneously. In any case, if only the performance in this intercomparison is considered, RMT-200 performed the best and is the recommended choice if a new fast response methane gas analyzer is needed.

  18. Measurements of methane emissions from natural gas gathering facilities and processing plants: measurement methods

    NASA Astrophysics Data System (ADS)

    Roscioli, J. R.; Yacovitch, T. I.; Floerchinger, C.; Mitchell, A. L.; Tkacik, D. S.; Subramanian, R.; Martinez, D. M.; Vaughn, T. L.; Williams, L.; Zimmerle, D.; Robinson, A. L.; Herndon, S. C.; Marchese, A. J.

    2015-05-01

    Increased natural gas production in recent years has spurred intense interest in methane (CH4) emissions associated with its production, gathering, processing, transmission, and distribution. Gathering and processing facilities (G&P facilities) are unique in that the wide range of gas sources (shale, coal-bed, tight gas, conventional, etc.) results in a wide range of gas compositions, which in turn requires an array of technologies to prepare the gas for pipeline transmission and distribution. We present an overview and detailed description of the measurement method and analysis approach used during a 20-week field campaign studying CH4 emissions from the natural gas G&P facilities between October 2013 and April 2014. Dual-tracer flux measurements and on-site observations were used to address the magnitude and origins of CH4 emissions from these facilities. The use of a second tracer as an internal standard revealed plume-specific uncertainties in the measured emission rates of 20-47%, depending upon plume classification. Combining downwind methane, ethane (C2H6), carbon monoxide (CO), carbon dioxide (CO2), and tracer gas measurements with on-site tracer gas release allows for quantification of facility emissions and in some cases a more detailed picture of source locations.

  19. Measurements of methane emissions from natural gas gathering facilities and processing plants: measurement methods

    NASA Astrophysics Data System (ADS)

    Roscioli, J. R.; Yacovitch, T. I.; Floerchinger, C.; Mitchell, A. L.; Tkacik, D. S.; Subramanian, R.; Martinez, D. M.; Vaughn, T. L.; Williams, L.; Zimmerle, D.; Robinson, A. L.; Herndon, S. C.; Marchese, A. J.

    2014-12-01

    Increased natural gas production in recent years has spurred intense interest in methane (CH4) emissions associated with its production, gathering, processing, transmission and distribution. Gathering and processing facilities (G&P facilities) are unique in that the wide range of gas sources (shale, coal-bed, tight gas, conventional, etc.) results in a wide range of gas compositions, which in turn requires an array of technologies to prepare the gas for pipeline transmission and distribution. We present an overview and detailed description of the measurement method and analysis approach used during a 20-week field campaign studying CH4 emissions from the natural gas G&P facilities between October 2013 and April 2014. Dual tracer flux measurements and onsite observations were used to address the magnitude and origins of CH4 emissions from these facilities. The use of a second tracer as an internal standard revealed plume-specific uncertainties in the measured emission rates of 20-47%, depending upon plume classification. Combining downwind methane, ethane (C2H6), carbon monoxide (CO), carbon dioxide (CO2), and tracer gas measurements with onsite tracer gas release allows for quantification of facility emissions, and in some cases a more detailed picture of source locations.

  20. Methane Emissions in the London Region: Deciphering Regional Sources with Mobile Measurements

    NASA Astrophysics Data System (ADS)

    Zazzeri, G.; Lowry, D.; Fisher, R. E.; France, J. L.; Lanoisellé, M.; Bjorkegren, A.; Nisbet, E. G.

    2014-12-01

    Methane stable isotope analysis, coupled with mole fraction measurement, has been used to link isotopic signature to methane emissions from the leading methane sources in the London region, such as landfills and gas leaks. A mobile Picarro G2301 CRDS analyser was installed in a vehicle, together with an anemometer and a Hemisphere GPS receiver, to measure atmospheric methane mole fractions and their relative location. When methane plumes were located and intercepted, air samples were collected in Tedlar bags, for δ13C-CH4 isotopic analysis by CF-GC-IRMS (Continous Flow-Gas Chromatography-Isotopic Ratio Mass Spectroscopy). This method provides high precision isotopic values, determining δ13C-CH4 to ±0.05 per mil. The bulk signature of the methane plume into the atmosphere from the whole source area was obtained by Keeling plot analysis, and a δ13C-CH4 signature, with the relative uncertainty, allocated to each methane source investigated. The averaged δ13C-CH4 signature for landfill sites around the London region is - 58 ± 3 ‰, whereas the δ13C-CH4 signature for gas leaks is fairly constant at -36 ± 2 ‰, a value characteristic of North Sea supply. The Picarro G2301 analyser was installed also on the roof of King's College London, located in the centre of the city, and connected to an air inlet located 7 meters above roof height. An auto-sampler was connected to the same air inlet and launched remotely when a high nocturnal build up was expected, allowing up to twenty air bags to be collected for methane isotopic analysis over a 24 hour period. The main source contributing to overnight methane build up in central London is fugitive gas, in agreement with inventories. From the isotopic characterisation of urban methane sources and the source mix in London, the contribution to the urban methane budget and the local distribution of the methane sources given in inventories can be validated.

  1. Methods for Measuring and Estimating Methane Emission from Ruminants

    PubMed Central

    Storm, Ida M. L. D.; Hellwing, Anne Louise F.; Nielsen, Nicolaj I.; Madsen, Jørgen

    2012-01-01

    Simple Summary Knowledge about methods used in quantification of greenhouse gasses is currently needed due to international commitments to reduce the emissions. In the agricultural sector one important task is to reduce enteric methane emissions from ruminants. Different methods for quantifying these emissions are presently being used and others are under development, all with different conditions for application. For scientist and other persons working with the topic it is very important to understand the advantages and disadvantage of the different methods in use. This paper gives a brief introduction to existing methods but also a description of newer methods and model-based techniques. Abstract This paper is a brief introduction to the different methods used to quantify the enteric methane emission from ruminants. A thorough knowledge of the advantages and disadvantages of these methods is very important in order to plan experiments, understand and interpret experimental results, and compare them with other studies. The aim of the paper is to describe the principles, advantages and disadvantages of different methods used to quantify the enteric methane emission from ruminants. The best-known methods: Chambers/respiration chambers, SF6 technique and in vitro gas production technique and the newer CO2 methods are described. Model estimations, which are used to calculate national budget and single cow enteric emission from intake and diet composition, are also discussed. Other methods under development such as the micrometeorological technique, combined feeder and CH4 analyzer and proxy methods are briefly mentioned. Methods of choice for estimating enteric methane emission depend on aim, equipment, knowledge, time and money available, but interpretation of results obtained with a given method can be improved if knowledge about the disadvantages and advantages are used in the planning of experiments. PMID:26486915

  2. 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.

  3. Direct Continuous Measurements of Methane Emissions from a Landfill: Method, Station and Latest Results

    NASA Astrophysics Data System (ADS)

    Burba, G. G.; Xu, L.; Lin, X.; Amen, J.; Welding, K.; McDermitt, D. K.

    2014-12-01

    Solar-powered automated flux station was deployed continuously inside the Bluff Road Landfill (Lincoln, NE) for the period of over4 years starting June 2010. Landfill methane emissions were measured using the eddy covariance method, reporting hourly emission rates. The data shown in this presentation are from the period of June to December 2010 when no gas recovery was in operation. The continuous measurements of hourly emission rates allowed a number of important analyses of the key factors affecting landfill methane emissions at different time scales. In particular, the results show that landfill methane emissions strongly depended on changes in barometric pressure. Rising barometric pressure suppressed the emission, while falling barometric pressure enhanced the emission, resulting in up to a 35-fold variation in day-to-day methane emissions. Wavelet coherence analysis revealed a strong spectral coherency between variations of barometric pressure and methane emission at periodicities ranging from 1 day to 8 days. Power spectrum and ogive analysis showed that at least 10 days of continuous measurements was needed in order to capture 90% of the total variance in the methane emission time series at the site.From these results, it is apparent that point-in-time measurements taken at monthly or longer time intervals using techniques such as the trace plume method, the mass balance method, or the closed-chamber method will be subject to large variations in measured emission rates because of the barometric pumping phenomenon. Estimates of long-term integrated methane emissions based on such measurements could yield uncertainties, ranging from 28% underestimation to 32% overestimation.The results demonstrate a need for continuous measurements to quantify annual total landfill emissions. This conclusion may also apply to the wetlands, peatlands, lakes, and other environments where emissions are from porous media or ebullition.

  4. Methane Footprint Measurements with IASI and GOSAT - Identification of Source Regions from Space

    NASA Astrophysics Data System (ADS)

    Malina, E.; Muller, J. P.; Walton, D.; Potts, D.

    2015-12-01

    To date, satellite instruments such as SCIAMACHY and GOSAT-TANSO-FTS have largely focused on regional scale methane output (Kort, A. E., et al. 2014), in order to gain insight into significant methane source regions (such as the Four Corners). However, such an approach does not tackle the root of the issue; the individual sources of methane that account for the total global methane budget, e.g. oil wells and marshland. In this study we aim to use existing satellite sensors onboard Metop and GOSAT to locate point sources of methane from space. We use nine years of global methane measurements from Metop-IASI A/B in order to exploit the exceptionally high global coverage of the instruments (total coverage of the Earth twice a day), and its relatively small spatial footprint in order to accurately identify these methane source regions. Using these data we show which regions have persistent sources (such as the Four Corners), and which are fugitive (methane bubbles in the Arctic), changing from one month to the next. Following the identification of significant source regions using IASI, we increase the resolution by cross-referencing with the higher spatial resolution (but patchy) GOSAT data, in order to answer the question of whether individual gas sources can be identified from space. This study partially follows the method proposed by Kort, who used SCIAMACHY to identify general areas of high methane release in the USA, focusing on the oilrigs in the Four Corners region. This study takes Kort's work further and attempts to identify individual sources (both natural and anthropogenic) using the GOSAT/IASI combination, backed up with ground-based knowledge of sources, such as the FrackTracker database and known natural sources such as the "Door to Hell" in Turkmenistan. Finally we show validation by comparing the individual footprints against methane measurements from the TCCON (Wunch, D., et al. 2010), thus providing confidence in the use of individual satellites

  5. 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.

  6. Methane and Ethane Measurements from a New TCCON Station in Los Angeles

    NASA Astrophysics Data System (ADS)

    Wunch, D.; Roehl, C. M.; Blavier, J. L.; Allen, N.; Treffers, R.; Toon, G. C.; Wennberg, P. O.

    2012-12-01

    The Los Angeles urban region emits large amounts of methane (~0.44Tg/year) into the atmosphere. It is currently unclear exactly how much of this is biogenic (landfills, cattle), and how much is from natural gas (natural seeps or fugitive emissions from the natural gas infrastructure). Since natural gas contains ethane, whereas biogenic emissions contain none, simultaneous measurements of ethane and methane offer the possibility of separating the biogenic versus natural gas emissions of methane. We investigate this using total column measurements from a new Total Carbon Column Observing Network (TCCON) remote sensing station in the Los Angeles suburb of Pasadena, which began measurements in July 2012. These measurements will be put into the context of historical remote sensing and in situ measurements described by Wennberg et al., 2012 (doi:10.1021/es301138y).

  7. Automated analyzer for aircraft measurements of atmospheric methane and total hydrocarbons

    NASA Technical Reports Server (NTRS)

    Cofer, W. R., III; Purgold, G. C.

    1981-01-01

    An automated methane/total hydrocarbon analyzer is presented, which can produce alternate methane/total hydrocarbon measurements every 7 seconds to provide the spatial resolution required for regional hydrocarbon measurements at aircraft speeds. The construction and sampling techniques developed for the aircraft mounted system are discussed. A technique to periodically measure atmosphere oxygen is incorporated into the analyzer to ensure accurate hydrocarbon measurements, and a data collection methodology is developed to minimize errors resulting from changes in flame ionization detector sensitivity at different altitudes. Aircraft data acquired at the 1979 Southeastern Virginia Urban Plume Study are also presented, which illustrate the application of the instrument to a troposphere pollution plume.

  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. Seasonal distribution of methane flux in Minnesota Peatland measured by eddy correlation

    SciTech Connect

    Shurpali, N.J.; Verma, S.B.; Clement, R.J.; Billesbach, D.P.

    1993-11-20

    Methane flux was measured using the micrometerological eddy correlation technique during 62 days in mid-May through mid-October 1991 in a peatland ecosystem in north central Minnesota. Application of this technique allows measurement of spatially integrated fluxes. The distribution of methane flux consisted of a gradual pattern with several episodic emissions superimposed. The gradual (nonepisodic) pattern of methane flux (daytime average) exhibited an increase from 30-120 mg m{sup {minus}2}/d in late May to early July to 125-160 mg m{sup {minus}2}/d in mid-July to mid-August and then a decline to 100-35 mg m{sup {minus}2}/d in early September to mid-October. Peat temperature (at 0.1 m depth) and water table depth accounted for about 70% of the variance in the methane flux data. The episodic emissions were associated with drops in atmospheric pressure and a declining water table. Generally, the hourly values of daytime methane flux were fairly stable, perhaps with a slight depression during the midday. However, on days with episodic emissions, the daytime methane flux had a peak during the midafternoon, and its pattern appeared to be similar to those of the standard deviation of atmospheric pressure flunctuations and mean horizontal wind velocity. The ratio of soil CO{sub 2} to methane fluxes (during nonepisodic emission periods) increased with increasing water table depth in a manner similar to that observed in a laboratory study of peat columns from different wetland types in Quebec. The annual methane emission for this ecosystem was estimated to be about 16-19.5 gm{sup {minus}2}yr{sup {minus}1}. 29 refs., 7 figs., 2 tabs.

  10. 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.

  11. 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.

  12. Eddy covariance measurements of methane fluxes over grazed native and improved prairies in Oklahoma

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although several studies have reported eddy covariance (EC) measurements at several tallgrass prairie sites to investigate the dynamics of carbon and water vapor fluxes, the EC measurements of methane (CH4) fluxes over grazed tallgrass prairie sites are lacking. CH4 fluxes were measured during the 2...

  13. High Frequency Measurements of Methane Concentrations and Carbon Isotopes at a Marsh and Landfill

    NASA Astrophysics Data System (ADS)

    Mortazavi, B.; Wilson, B.; Chanton, J.; Eller, K.; Dong, F.; Baer, D. S.; Gupta, M.; Dzwonkowski, B.

    2012-12-01

    High frequency measurements of methane concentrations and carbon isotopes can help constrain the source strengths of methane emitted to the atmosphere. We report here methane concentrations and 13C values measured at 0.5 Hz with cavity enhanced laser absorption spectrometers (Los Gatos Research) deployed at a saltmarsh in Alabama and a landfill in Florida. Methane concentrations and 13C at the saltmarsh were monitored over a 2.5 day time period at 2 m, 0.5 m above the ground as well as from the outflow of a flow-through (2 L) chamber placed on the Spartina alterniflora dominated marsh. A typical measurement cycle included regular samples from two tanks of known methane concentrations and isotopic values and from ambient air samples. Over the 2.5-day measurement period methane concentrations and isotopic ratios at 2 m averaged 1.85 ppm and -43.57‰ (±0.34, 1 SE), respectively. The concentration and isotopic values from the chamber outflow varied from 1.92 to 5.81 ppm and -38.5 to -59.3‰, respectively. Methane flux from the marsh ranged from undetectable to 3.6 mgC m-2hr-1, with high fluxes measured during low tide. The 13δCH4 of the emitted CH4 from the marsh, determined from a mass balance equation using the chamber inflow and outflow concentration and isotopic values ranged from -62.1 to -93.9‰ and averaged -77‰ (±1.25, 1SE). At the landfill ambient methane concentrations and 13C ratios measured over multiple days varied from 4.25 to 11.91 ppm and from -58.81 to -45.12‰, respectively. At higher methane concentrations the δ13C of CH4 was more depleted consistent with previously observed relationship at this site made by more traditional techniques. Over a 30-minute measurement period CH4 concentrations at the landfill could vary by as much as 15 ppm. The high frequency continuous optical measurements with field-deployed instruments provide us with an unprecedented temporal resolution of CH4 concentrations and isotopic ratios. These measurements will

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Measured temperature and pressure dependence of Vp and Vs in compacted, polycrystalline sI methane and sII methane-ethane hydrate

    USGS Publications Warehouse

    Helgerud, M.B.; Waite, W.F.; Kirby, S.H.; Nur, A.

    2003-01-01

    We report on compressional- and shear-wave-speed measurements made on compacted polycrystalline sI methane and sII methane-ethane hydrate. The gas hydrate samples are synthesized directly in the measurement apparatus by warming granulated ice to 17??C in the presence of a clathrate-forming gas at high pressure (methane for sI, 90.2% methane, 9.8% ethane for sII). Porosity is eliminated after hydrate synthesis by compacting the sample in the synthesis pressure vessel between a hydraulic ram and a fixed end-plug, both containing shear-wave transducers. Wave-speed measurements are made between -20 and 15??C and 0 to 105 MPa applied piston pressure.

  2. A novel methodology to measure methane bubble sizes in the water column

    NASA Astrophysics Data System (ADS)

    Hemond, H.; Delwiche, K.; Senft-Grupp, S.; Manganello, T.

    2014-12-01

    The fate of methane ebullition from lake sediments is dependent on initial bubble size. Rising bubbles are subject to dissolution, reducing the fraction of methane that ultimately enters the atmosphere while increasing concentrations of aqueous methane. Smaller bubbles not only rise more slowly, but dissolve more rapidly larger bubbles. Thus, understanding methane bubble size distributions in the water column is critical to predicting atmospheric methane emissions from ebullition. However, current methods of measuring methane bubble sizes in-situ are resource-intensive, typically requiring divers, video equipment, sonar, or hydroacoustic instruments. The complexity and cost of these techniques points to the strong need for a simple, autonomous device that can measure bubble size distributions and be deployed unattended over long periods of time. We describe a bubble sizing device that can be moored in the subsurface and can intercept and measure the size of bubbles as they rise. The instrument uses a novel optical measurement technique with infrared LEDs and IR-sensitive photodetectors combined with a custom-designed printed circuit board. An on-board microcomputer handles raw optical signals and stores the relevant information needed to calculate bubble volume. The electronics are housed within a pressure case fabricated from standard PVC fittings and are powered by size C alkaline batteries. The bill of materials cost is less than $200, allowing us to deploy multiple sensors at various locations within Upper Mystic Lake, MA. This novel device will provide information on how methane bubble sizes may vary both spatially and temporally. We present data from tests under controlled laboratory conditions and from deployments in Upper Mystic Lake.

  3. Numerical simulations to assess the tracer dilution method for measurement of landfill methane emissions.

    PubMed

    Taylor, Diane M; Chow, Fotini K; Delkash, Madjid; Imhoff, Paul T

    2016-10-01

    Landfills are a significant contributor to anthropogenic methane emissions, but measuring these emissions can be challenging. This work uses numerical simulations to assess the accuracy of the tracer dilution method, which is used to estimate landfill emissions. Atmospheric dispersion simulations with the Weather Research and Forecast model (WRF) are run over Sandtown Landfill in Delaware, USA, using observation data to validate the meteorological model output. A steady landfill methane emissions rate is used in the model, and methane and tracer gas concentrations are collected along various transects downwind from the landfill for use in the tracer dilution method. The calculated methane emissions are compared to the methane emissions rate used in the model to find the percent error of the tracer dilution method for each simulation. The roles of different factors are examined: measurement distance from the landfill, transect angle relative to the wind direction, speed of the transect vehicle, tracer placement relative to the hot spot of methane emissions, complexity of topography, and wind direction. Results show that percent error generally decreases with distance from the landfill, where the tracer and methane plumes become well mixed. Tracer placement has the largest effect on percent error, and topography and wind direction both have significant effects, with measurement errors ranging from -12% to 42% over all simulations. Transect angle and transect speed have small to negligible effects on the accuracy of the tracer dilution method. These tracer dilution method simulations provide insight into measurement errors that might occur in the field, enhance understanding of the method's limitations, and aid interpretation of field data.

  4. Airborne measurements of CO2, CH4 and HCN in boreal biomass burning plumes

    NASA Astrophysics Data System (ADS)

    O'Shea, Sebastian J.; Bauguitte, Stephane; Muller, Jennifer B. A.; Le Breton, Michael; Archibald, Alex; Gallagher, Martin W.; Allen, Grant; Percival, Carl J.

    2013-04-01

    Biomass burning plays an important role in the budgets of a variety of atmospheric trace gases and particles. For example, fires in boreal Russia have been linked with large growths in the global concentrations of trace gases such as CO2, CH4 and CO (Langenfelds et al., 2002; Simpson et al., 2006). High resolution airborne measurements of CO2, CH4 and HCN were made over Eastern Canada onboard the UK Atmospheric Research Aircraft FAAM BAe-146 from 12 July to 4 August 2011. These observations were made as part of the BORTAS project (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites). Flights were aimed at transecting and sampling the outflow from the commonly occurring North American boreal forest fires during the summer months and to investigate and identify the chemical composition and evolution of these plumes. CO2 and CH4 dry air mole fractions were determined using an adapted system based on a Fast Greenhouse Gas Analyser (FGGA, Model RMT-200) from Los Gatos Research Inc, which uses the cavity enhanced absorption spectroscopy technique. In-flight calibrations revealed a mean accuracy of 0.57 ppmv and 2.31 ppbv for 1 Hz observations of CO2 and CH4, respectively, during the BORTAS project. During these flights a number of fresh and photochemically-aged plumes were identified using simultaneous HCN measurements. HCN is a distinctive and useful marker for forest fire emissions and it was detected using chemical ionisation mass spectrometry (CIMS). In the freshest plumes, strong relationships were found between CH4, CO2 and other tracers for biomass burning. From this we were able to estimate that 8.5 ± 0.9 g of CH4 and 1512 ± 185 g of CO2 were released into the atmosphere per kg of dry matter burnt. These emission factors are in good agreement with estimates from previous studies and can be used to calculate budgets for the region. However for aged plumes the correlations between CH4 and other

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Quantifying Urban Natural Gas Leaks from Street-level Methane Mapping: Measurements and Uncertainty

    NASA Astrophysics Data System (ADS)

    von Fischer, J. C.; Ham, J. M.; Griebenow, C.; Schumacher, R. S.; Salo, J.

    2013-12-01

    Leaks from the natural gas pipeline system are a significant source of anthropogenic methane in urban settings. Detecting and repairing these leaks will reduce the energy and carbon footprints of our cities. Gas leaks can be detected from spikes in street-level methane concentrations measured by analyzers deployed on vehicles. While a spike in methane concentration indicates a leak, an algorithm (e.g., inverse model) must be used to estimate the size of the leak (i.e., flux) from concentration data and supporting meteorological information. Unfortunately, this drive-by approach to leak quantification is confounded by the complexity of urban roughness, changing weather conditions, and other incidental factors (e.g., traffic, vehicle speed, etc.). Furthermore, the vehicle might only pass through the plume one to three times during routine mapping. The objective of this study was to conduct controlled release experiments to better quantify the relationship between mobile methane concentration measurements and the size and location of the emission source (e.g., pipeline leakage) in an urban environment. A portable system was developed that could release methane at known rates between 10 and 40 LPM while maintaining concentrations below the lower explosive limit. A mapping vehicle was configured with fast response methane analyzers, GPS, and meteorological instruments. Portable air-sampling tripods were fabricated that could be deployed at defined distances downwind from the release point and automatically-triggered to collect grab samples. The experimental protocol was as follows: (1) identify an appropriate release point within a city, (2) release methane at a known rate, (3) measure downwind street-level concentrations with the vehicle by making multiple passes through the plume, and (4) collect supporting concentration and meteorological data with the static tripod samplers deployed in the plume. Controlled release studies were performed at multiple locations and

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. Latest on Mobile Methane Measurements with Fast Open-Path Technology: Experiences, Opportunities & Perspectives

    NASA Astrophysics Data System (ADS)

    Burba, George; Anderson, Tyler; Ediger, Kevin; von Fischer, Joseph; Gioli, Beniamino; Ham, Jay; Hupp, Jason; Kohnert, Katrin; Larmanou, Eric; Levy, Peter; Polidori, Andrea; Pikelnaya, Olga; Price, Eric; Sachs, Torsten; Serafimovich, Andrei; Zondlo, Mark; Zulueta, Rommel

    2016-04-01

    Methane plays a critical role in the radiation balance, chemistry of the atmosphere, and air quality. The major sources of methane include agricultural and natural production, landfill emissions, oil and gas development sites, and natural gas distribution networks in rural and urban environments. The majority of agricultural and natural methane production occurs in areas with little infrastructure or easily available grid power (e.g., rice fields, arctic and boreal wetlands, tropical mangroves, etc.) Past approaches for direct measurements of methane fluxes relied on fast closed-path analyzers, which typically require powerful pumps and grid power. Power and labor demands may be among the key reasons why such methane fluxes were often measured at locations with good infrastructure and grid power, and not necessarily with high methane production. Landfill methane emissions were traditionally assessed via point-in-time measurements taken at monthly or longer time intervals using techniques such as the trace plume method, the mass balance method, etc. These are subject to large uncertainties because of the snapshot nature of the measurements, while the changes in emission rates are continuous due to ongoing landfill development, changes in management practices, and the barometric pumping phenomenon. Installing a continuously operating flux station in the middle of an active landfill requires a low-power approach with no cables stretching across the landfill. The majority of oil and gas and urban methane emission happens via variable-rate point sources or diffused spots in topographically challenging terrains, such as street tunnels, elevated locations at water treatment plants, vents, etc. Locating and measuring methane emissions from such sources is challenging when using traditional micrometeorological techniques, and requires development of novel approaches. In 2010, a new lightweight high-speed high-resolution open-path technology was developed with the goal of

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  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. 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.

  2. 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

  3. 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.

  4. Thermal conductivity measurements in Porous mixtures of methane hydrate and quartz sand

    USGS Publications Warehouse

    Waite, W.F.; deMartin, B.J.; Kirby, S.H.; Pinkston, J.; Ruppel, C.D.

    2002-01-01

    Using von Herzen and Maxwell's needle probe method, we measured thermal conductivity in four porous mixtures of quartz sand and methane gas hydrate, with hydrate composing 0, 33, 67 and 100% of the solid volume. Thermal conductivities were measured at a constant methane pore pressure of 24.8 MPa between -20 and +15??C, and at a constant temperature of -10??C between 3.5 and 27.6 MPa methane pore pressure. Thermal conductivity decreased with increasing temperature and increased with increasing methane pore pressure. Both dependencies weakened with increasing hydrate content. Despite the high thermal conductivity of quartz relative to methane hydrate, the largest thermal conductivity was measured in the mixture containing 33% hydrate rather than in hydrate-free sand. This suggests gas hydrate enhanced grain-to-grain heat transfer, perhaps due to intergranular contact growth during hydrate synthesis. These results for gas-filled porous mixtures can help constrain thermal conductivity estimates in porous, gas hydrate-bearing systems.

  5. Eddy Covariance Measurements of Methane Flux Using an Open-Path Gas Analyzer

    NASA Astrophysics Data System (ADS)

    Burba, G.; Anderson, T.; Zona, D.; Schedlbauer, J.; Anderson, D.; Eckles, R.; Hastings, S.; Ikawa, H.; McDermitt, D.; Oberbauer, S.; Oechel, W.; Riensche, B.; Starr, G.; Sturtevant, C.; Xu, L.

    2008-12-01

    Methane is an important greenhouse gas with a warming potential of about 23 times that of carbon dioxide over a 100-year cycle (Houghton et al., 2001). Measurements of methane fluxes from the terrestrial biosphere have mostly been made using flux chambers, which have many advantages, but are discrete in time and space and may disturb surface integrity and air pressure. Open-path analyzers offer a number of advantages for measuring methane fluxes, including undisturbed in- situ flux measurements, spatial integration using the Eddy Covariance approach, zero frequency response errors due to tube attenuation, confident water and thermal density terms from co-located fast measurements of water and sonic temperature, and remote deployment due to lower power demands in the absence of a pump. The prototype open-path methane analyzer is a VCSEL (vertical-cavity surface-emitting laser)-based instrument. It employs an open Herriott cell and measures levels of methane with RMS noise below 6 ppb at 10 Hz sampling in controlled laboratory environment. Field maintenance is minimized by a self-cleaning mechanism to keep the lower mirror free of contamination. Eddy Covariance measurements of methane flux using the prototype open-path methane analyzer are presented for the period between 2006 and 2008 in three ecosystems with contrasting weather and moisture conditions: (1) Fluxes over a short-hydroperiod sawgrass wetland in the Florida Everglades were measured in a warm and humid environment with temperatures often exceeding 25oC, variable winds, and frequent heavy dew at night; (2) Fluxes over coastal wetlands in an Arctic tundra were measured in an environment with frequent sub-zero temperatures, moderate winds, and ocean mist; (3) Fluxes over pacific mangroves in Mexico were measured in an environment with moderate air temperatures high winds, and sea spray. Presented eddy covariance flux data were collected from a co-located prototype open-path methane analyzer, LI-7500, and

  6. Field intercomparison of four methane gas analysers suitable for eddy covariance flux measurements

    NASA Astrophysics Data System (ADS)

    Peltola, O.; Mammarella, I.; Haapanala, S.; Burba, G.; Vesala, T.

    2012-12-01

    Performances of four methane gas analyzers suitable for eddy covariance measurements are assessed. The assessment and comparison was performed by analyzing eddy covariance data obtained during summer 2010 (1 April to 26 October) at a pristine fen, Siikaneva, Southern Finland. High methane fluxes with pronounced seasonality have been measured at this fen. The four participating methane gas analyzers are commercially available closed-path units TGA-100A (Campbell Scientific Inc., USA), RMT-200 (Los Gatos Research, USA), G1301-f (Picarro Inc., USA) and an early prototype open-path unit Prototype-7700 (LI-COR Biosciences, USA). The RMT-200 functioned most reliably throughout the measurement campaign, during low and high flux periods. Methane fluxes from RMT-200 and G1301-f had the smallest random errors and the fluxes agree remarkably well throughout the measurement campaign. Cospectra and power spectra calculated from RMT-200 and G1301-f data agree well with corresponding temperature spectra during a high flux period. None of the gas analysers showed statistically significant diurnal variation for methane flux. Prototype-7700 functioned only for a short period of time, over one month, in the beginning of the measurement campaign during low flux period, and thus, its overall accuracy and long-term performance were not assessed. Prototype-7700 is a practical choice for measurement sites in remote locations due to its low power demand, however if only the performance in this intercomparison is considered, RMT-200 performed the best and is the recommended choice if a new fast response methane gas analyser is needed.

  7. 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

  8. 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

  9. Development of a new platform for airborne measurements of atmospheric CO2 and CH4 and comparison with GOSAT measurements at Railroad Valley playa, Nevada

    NASA Astrophysics Data System (ADS)

    Tadic, J.; Loewenstein, M.; Iraci, L. T.; Gore, W.; Schiro, K. A.; Olson, R. A.; Sheffner, E. J.; Yates, E. L.

    2011-12-01

    Measurements of carbon dioxide (CO2) play an important role in understanding the global carbon cycle and its contribution to global warming. In recent years methane (CH4) has received increasing attention as the second most important anthropogenic greenhouse gas because of the high uncertainty of its sources and sinks. Aircraft measurements of greenhouse gases are essential for observations in the free troposphere and lower stratosphere to better understand changes at regional and continental scales. Recently new types of high-accuracy analyzers based on cavity-ring down spectroscopy have become available for use on aircraft. One of them, Picarro 2301-m, was remodeled and adapted for use outside the cabin of an Alpha Jet. In this unique attempt, the instrument was redesigned from a single unit to multiple units that fit inside the Alpha jet wing pod, with special emphasis on internal thermal management. After remodeling, the platform was tested in a laboratory, in a chamber with variable pressure and temperature, and in the field. This newly developed platform exhibits several important characteristics: the modular structure of the platform allows usage of other instruments simultaneously, the platform is capable of measuring both vertical and horizontal profiles of CO2 and CH4, and it is very insensitive to flight maneuvers. The new platform was used on 22-26th of June, 2011, to create spatial and temporal profiles of CO2 and CH4 over a playa in Railroad Valley, Nevada, USA. The playa is a flat, dry lakebed with virtually no vegetation, approximately 15 km x 15 km in size, 1434 m in elevation and 110 km southwest of the nearest city (Ely, Nevada). The time and location of flights were selected to coincide with the overpass of Greenhouse Gases Observing Satellite (GOSAT). Airborne (Alpha Jet) in-situ measurements of CO2 and CH4 were collected to support the vicarious calibration experiment to validate column-averaged dry air mole fractions of CO2 and CH4 (XCO2 and

  10. The Application of Methane Clumped Isotope Measurements to Determine the Source of Large Methane Seeps in Alaskan Lakes

    NASA Astrophysics Data System (ADS)

    Douglas, P. M.; Stolper, D. A.; Eiler, J. M.; Sessions, A. L.; Walter Anthony, K. M.

    2014-12-01

    Natural methane emissions from the Arctic present an important potential feedback to global warming. Arctic methane emissions may come from either active microbial sources or from deep fossil reservoirs released by the thawing of permafrost and melting of glaciers. It is often difficult to distinguish between and quantify contributions from these methane sources based on stable isotope data. Analyses of methane clumped isotopes (isotopologues with two or more rare isotopes such as 13CH3D) can complement traditional stable isotope-based classifications of methane sources. This is because clumped isotope abundances (for isotopically equilibrated systems) are a function of temperature and can be used to identify pathways of methane generation. Additionally, distinctive effects of mixing on clumped isotope abundances make this analysis valuable for determining the origins of mixed gasses. We find large variability in clumped isotope compositions of methane from seeps in several lakes, including thermokarst lakes, across Alaska. At Lake Sukok in northern Alaska we observe the emission of dominantly thermogenic methane, with a formation temperature of at least 100° C. At several other lakes we find evidence for mixing between thermogenic methane and biogenic methane that forms in low-temperature isotopic equilibrium. For example, at Eyak Lake in southeastern Alaska, analysis of three methane samples results in a distinctive isotopic mixing line between a high-temperature end-member that formed between 100-170° C, and a biogenic end-member that formed in isotopic equilibrium between 0-20° C. In this respect, biogenic methane in these lakes resembles observations from marine gas seeps, oil degradation, and sub-surface aquifers. Interestingly, at Goldstream Lake in interior Alaska, methane with strongly depleted clumped-isotope abundances, indicative of disequilibrium gas formation, is found, similar to observations from methanogen culture experiments.

  11. 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

  12. 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.

  13. Performance of a low-cost methane sensor for ambient concentration measurements in preliminary studies

    NASA Astrophysics Data System (ADS)

    Eugster, W.; Kling, G. W.

    2012-03-01

    Methane is the second most important greenhouse gas after CO2 and contributes to global warming. Its sources are not uniformly distributed across terrestrial and aquatic ecosystems, and most of the methane flux is expected to stem from hotspots which often occupy a very small fraction of the total landscape area. Continuous time-series measurements of CH4 concentrations can help identify and locate these methane hot-spots. Newer, low-cost trace gas sensors such as the Figaro TGS 2600 can detect CH4 even at ambient concentrations. Hence, in this paper we tested this sensor under real-world conditions over Toolik Lake, Alaska, to determine its suitability for preliminary studies before placing more expensive and service-intensive equipment at a given locality. A reasonably good agreement with parallel measurements made using a Los Gatos Research FMA 100 methane analyzer was found after removal of the strong cross-sensitivities for temperature and relative humidity. Correcting for this cross-sensitivity increased the absolute accuracy required for in-depth studies, and the reproducibility between two TGS 2600 sensors run in parallel is very good. We conclude that the relative CH4 concentrations derived from such sensors are sufficient for preliminary investigations in the search of potential methane hot-spots.

  14. Performance of a low-cost methane sensor for ambient concentration measurements in preliminary studies

    NASA Astrophysics Data System (ADS)

    Eugster, W.; Kling, G. W.

    2012-08-01

    Methane is the second most important greenhouse gas after CO2 and contributes to global warming. Its sources are not uniformly distributed across terrestrial and aquatic ecosystems, and most of the methane flux is expected to stem from hotspots which often occupy a very small fraction of the total landscape area. Continuous time-series measurements of CH4 concentrations can help identify and locate these methane hotspots. Newer, low-cost trace gas sensors such as the Figaro TGS 2600 can detect CH4 even at ambient concentrations. Hence, in this paper we tested this sensor under real-world conditions over Toolik Lake, Alaska, to determine its suitability for preliminary studies before placing more expensive and service-intensive equipment at a given locality. A reasonably good agreement with parallel measurements made using a Los Gatos Research FMA 100 methane analyzer was found after removal of the strong sensitivities for temperature and relative humidity. Correcting for this sensitivity increased the absolute accuracy required for in-depth studies, and the reproducibility between two TGS 2600 sensors run in parallel is very good. We conclude that the relative CH4 concentrations derived from such sensors are sufficient for preliminary investigations in the search of potential methane hotspots.

  15. 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.

  16. 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

  17. 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.

  18. LOW-POWER SOLUTION FOR EDDY COVARIANCE MEASUREMENTS OF METHANE FLUX

    NASA Astrophysics Data System (ADS)

    Anderson, T.; Burba, G. G.; Komissarov, A.; McDermitt, D. K.; Xu, L.; Zona, D.; Oechel, W. C.; Schedlbauer, J. L.; Oberbauer, S. F.; Riensche, B.; Allyn, D.

    2009-12-01

    Open-path analyzers offer a number of advantages for measuring methane fluxes, including undisturbed in-situ flux measurements, spatial integration using the Eddy Covariance approach, zero frequency response errors due to tube attenuation, confident water and thermal density terms from co-located fast measurements of water and sonic temperature, and possibility of remote and mobile solar-powered or small-generator-powered deployments due to lower power demands in the absence of a pump. The LI-7700 open-path methane analyzer is a VCSEL (vertical-cavity surface-emitting laser)-based instrument. It employs an open Herriott cell and measures levels of methane with RMS noise below 5 ppb at 10 Hz sampling in controlled laboratory conditions. The power consumption of the stand-alone LI-7700 in steady-state is about 8W, so it can be deployed in any methane-generating location of interest on a portable or mobile solar-powered tower, and it does not have to have grid power or permanent industrial generator. Eddy Covariance measurements of methane flux using the LI-7700 open-path methane analyzer were conducted in 2006-2009 in five ecosystems with contrasting weather and moisture conditions: (1) sawgrass wetland in the Florida Everglades; (2) coastal wetlands in an Arctic tundra; and (3) pacific mangroves in Mexico; (4) maize field and (5) ryegrass field in Nebraska. Methane co-spectra behaved in a manner similar to that of the co-spectra of carbon dioxide, water vapor, and air temperature, demonstrating that the LI-7700 adequately measured fluctuations in methane concentration across the whole spectrum of frequencies contributing to vertical atmospheric turbulent transport at the experimental sites. All co-spectra also closely followed the Kaimal model, and demonstrated good agreement with another methane co-spectrum obtained with a TDLS (Tunable Diode Laser Spectroscope; Unisearch Associates, Inc.) over a peatland. Overall, hourly methane fluxes ranged from near-zero at

  19. 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.

  20. 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.

  1. Measurements of methane emissions from landfills using mobile plume method with trace gas and cavity ring-down spectroscopy

    NASA Astrophysics Data System (ADS)

    Mønster, J.; Kjeldsen, P.; Scheutz, C.

    2012-04-01

    Methane is emitted to the atmosphere from both anthropogenic and natural sources. One of the major anthropogenic sources is methane produced by bacteria in anaerobic environments such as rice pads and landfills. Land filling has for many years been the preferred waste disposal method, resulting in a large methane production with a large contribution to the global increase in atmospheric green house gas concentration. Several steps have been taken to reduce the emission of methane from landfills. In order to validate the effect of these steps, a measurement method is needed to quantify methane emissions with a large spatial variation. One method is to use a highly sensitive and fast analytical method, capable of measuring the atmospheric concentration methane downwind from emission areas. Combined with down-wind measurements of a trace gas, emitted at a controlled mass flow rate, the methane emission can be calculated. This method is called the mobile plume method, as the whole plume is measured by doing several transects. In the current study a methane/acetylene analyzer with cavity ring-down spectroscopy detection (Picarro, G2203) was used to estimate methane from a number of Danish landfills. We measured at both active and closed landfills and investigated the difference in methane emission. At landfills where the emissions could have more than one origin, the source strength of the different emission areas was determined by accurate trace gas positioning and choosing appropriate wind speed and measurement distance. To choose these factors, we addressed the uncertainties and limitations of the method with respect to the configuration of the trace gas bottles and the distance between the emission area and the measurement points. Composting of organic material in large piles was done at several of the investigated landfills and where possible, the methane emission from this partly anaerobic digestion was measured as a separate emission.

  2. Preliminary investigation into feasibility of dissolved methane measurement using cavity ringdown spectroscopy technique

    NASA Astrophysics Data System (ADS)

    Wang, Zhen-Nan; Ye, Wang-Quan; Luan, Xiao-Ning; Qi, Fu-Jun; Cheng, Kai; Zheng, Ronger

    2016-12-01

    For the exploration of gas hydrate resources by measuring the dissolved methane concentration in seawater, a continuous-wave cavity ringdown spectroscopy (CW-CRDS) experimental setup was constructed for trace methane detection. A current-modulation method, rather than a cavity-modulation method using an optical switch and a piezoelectric transducer, was employed to realize the cavity excitation and shutoff. Such a current-modulation method enabled the improvement of the experimental setup construction and stability, and the system size and stability are critical for a sensor to be deployed underwater. Ringdown data acquisition and processing were performed, followed by an evaluation of the experimental setup stability and sensitivity. The obtained results demonstrate that great errors are introduced when a large fitting window is selected if the analog-to-digital converter has an insufficient resolution. The ringdown spectrum of methane corresponding to the 2 v 3 band R(4) branch was captured, and the methane concentration in lab air was determined to be 2.06 ppm. Further experiments for evaluating the quantitative ability of this CW-CRDS experimental setup are underway from which a high-sensitivity methane sensor that can be combined with a degassing system is expected.

  3. 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.

  4. 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

  5. Network monitoring of speciated vs. total non-methane hydrocarbon measurements

    NASA Astrophysics Data System (ADS)

    Chen, Sheng-Po; Liao, Wei-Cheng; Chang, Chih-Chung; Su, Yuan-Chang; Tong, Yu-Huei; Chang, Julius S.; Wang, Jia-Lin

    2014-06-01

    The total non-methane hydrocarbon (TNMHC) level in the atmosphere is defined as the level of total hydrocarbons minus the level of methane. TNMHC observations are made in selected air quality stations (AQS) of Environmental Protection Agency (EPA) across Taiwan. The AQS network is also complemented by a network of photochemical assessment monitoring stations (PAMS) to provide hourly observations of 56 speciated non-methane hydrocarbons (NMHCs). In this study, the relationship between the AQS and PAMS TNMHC values was cross-examined for the period of 2007-2011 at four sites that conducted both types of measurements. Although the two observations differ in their methods of collection, the variations in the two datasets showed high synchronicity. However, because some of the NMHCs were missed in the summation of 56 species, the PAMS TNMHC values were consistently lower than those of the AQS TNMHC by an average of 30%.

  6. Methane emissions measured at two California landfills by OTM-10 and an acetylene tracer method

    EPA Science Inventory

    Methane emissions were measured at two municipal solid waste landfills in California using static flux chambers, an optical remote sensing approach known as vertical radial plume mapping (VRPM) using a tunable diode laser (TDL) and a novel acetylene tracer method. The tracer meth...

  7. Species and temperature measurements of methane oxidation in a nanosecond repetitively pulsed discharge

    PubMed Central

    Lefkowitz, Joseph K; Guo, Peng; Rousso, Aric; Ju, Yiguang

    2015-01-01

    Speciation and temperature measurements of methane oxidation during a nanosecond repetitively pulsed discharge in a low-temperature flow reactor have been performed. Measurements of temperature and formaldehyde during a burst of pulses were made on a time-dependent basis using tunable diode laser absorption spectroscopy, and measurements of all other major stable species were made downstream of a continuously pulsed discharge using gas chromatography. The major species for a stoichiometric methane/oxygen/helium mixture with 75% dilution are H2O, CO, CO2, H2, CH2O, CH3OH, C2H6, C2H4 and C2H2. A modelling tool to simulate homogeneous plasma combustion kinetics is assembled by combining the ZDPlasKin and CHEMKIN codes. In addition, a kinetic model for plasma-assisted combustion (HP-Mech/plasma) of methane, oxygen and helium mixtures has been assembled to simulate the measurements. Predictions can accurately capture reactant consumption as well as production of the major product species. However, significant disagreement is found for minor species, particularly CH2O and CH3OH. Further analysis revealed that the plasma-activated low-temperature oxidation pathways, particularly those involving CH3O2 radical reactions and methane reactions with O(1D), are responsible for this disagreement. PMID:26170433

  8. The Australian methane budget: Interpreting surface and train-borne measurements using a chemistry transport model

    NASA Astrophysics Data System (ADS)

    Fraser, Annemarie; Chan Miller, Christopher; Palmer, Paul I.; Deutscher, Nicholas M.; Jones, Nicholas B.; Griffith, David W. T.

    2011-10-01

    We investigate the Australian methane budget from 2005-2008 using the GEOS-Chem 3D chemistry transport model, focusing on the relative contribution of emissions from different sectors and the influence of long-range transport. To evaluate the model, we use in situ surface measurements of methane, methane dry air column average (XCH4) from ground-based Fourier transform spectrometers (FTSs), and train-borne surface concentration measurements from an in situ FTS along the north-south continental transect. We use gravity anomaly data from Gravity Recovery and Climate Experiment to describe the spatial and temporal distribution of wetland emissions and scale it to a prior emission estimate, which better describes observed atmospheric methane variability at tropical latitudes. The clean air sites of Cape Ferguson and Cape Grim are the least affected by local emissions, while Wollongong, located in the populated southeast with regional coal mining, samples the most locally polluted air masses (2.5% of the total air mass versus <1% at other sites). Averaged annually, the largest single source above background of methane at Darwin is long-range transport, mainly from Southeast Asia, accounting for ˜25% of the change in surface concentration above background. At Cape Ferguson and Cape Grim, emissions from ruminant animals are the largest source of methane above background, at approximately 20% and 30%, respectively, of the surface concentration. At Wollongong, emissions from coal mining are the largest source above background representing 60% of the surface concentration. The train data provide an effective way of observing transitions between urban, desert, and tropical landscapes.

  9. 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.

  10. 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.

  11. Comparison of Landfill Methane Oxidation Measured Using Stable Isotope Analysis and CO2/CH4 Fluxes Measured by the Eddy Covariance Method

    NASA Astrophysics Data System (ADS)

    Xu, L.; Chanton, J.; McDermitt, D. K.; Li, J.; Green, R. B.

    2015-12-01

    Methane plays a critical role in the radiation balance and chemistry of the atmosphere. Globally, landfill methane emission contributes about 10-19% of the anthropogenic methane burden into the atmosphere. In the United States, 18% of annual anthropogenic methane emissions come from landfills, which represent the third largest source of anthropogenic methane emissions, behind enteric fermentation and natural gas and oil production. One uncertainty in estimating landfill methane emissions is the fraction of methane oxidized when methane produced under anaerobic conditions passes through the cover soil. We developed a simple stoichiometric model to estimate methane oxidation fraction when the anaerobic CO2 / CH4 production ratio is known, or can be estimated. The model predicts a linear relationship between CO2 emission rates and CH4 emission rates, where the slope depends on anaerobic CO2 / CH4 production ratio and the fraction of methane oxidized, and the intercept depends on non-methane-dependent oxidation processes. The model was tested using carbon dioxide emission rates (fluxes) and methane emission rates (fluxes) measured using the eddy covariance method over a one year period at the Turkey Run landfill in Georgia, USA. The CO2 / CH4 production ratio was estimated by measuring CO2 and CH4 concentrations in air sampled under anaerobic conditions deep inside the landfill. We also used a mass balance approach to independently estimate fractional oxidation based on stable isotope measurements (δ13C of methane) of gas samples taken from deep inside the landfill and just above the landfill surface. Results from the two independent methods agree well. The model will be described and methane oxidation will be discussed in relation to wind direction, location at the landfill, and age of the deposited refuse.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Comparison of Field Measurements to Methane Emissions Models at a New Landfill.

    PubMed

    De la Cruz, Florentino B; Green, Roger B; Hater, Gary R; Chanton, Jeffrey P; Thoma, Eben D; Harvey, Tierney A; Barlaz, Morton A

    2016-09-06

    Estimates of methane emissions from landfills rely primarily on models due to both technical and economic limitations. While models are easy to implement, there is uncertainty due to the use of parameters that are difficult to validate. The objective of this research was to compare modeled emissions using several greenhouse gas (GHG) emissions reporting protocols including: (1) Intergovernmental Panel on Climate Change (IPCC); (2) U.S. Environmental Protection Agency Greenhouse Gas Reporting Program (EPA GHGRP); (3) California Air Resources Board (CARB); and (4) Solid Waste Industry for Climate Solutions (SWICS), with measured emissions data collected over three calendar years from a young landfill with no gas collection system. By working with whole landfill measurements of fugitive methane emissions and methane oxidation, the collection efficiency could be set to zero, thus eliminating one source of parameter uncertainty. The models consistently overestimated annual methane emissions by a factor ranging from 4-31. Varying input parameters over reasonable ranges reduced this range to 1.3-8. Waste age at the studied landfill was less than four years and the results suggest the need for measurements at additional landfills to evaluate the accuracy of the tested models to young landfills.

  20. Direct measurement of methane hydrate composition along the hydrate equilibrium boundary

    USGS Publications Warehouse

    Circone, S.; Kirby, S.H.; Stern, L.A.

    2005-01-01

    The composition of methane hydrate, namely nW for CH 4??nWH2O, was directly measured along the hydrate equilibrium boundary under conditions of excess methane gas. Pressure and temperature conditions ranged from 1.9 to 9.7 MPa and 263 to 285 K. Within experimental error, there is no change in hydrate composition with increasing pressure along the equilibrium boundary, but nW may show a slight systematic decrease away from this boundary. A hydrate stoichiometry of n W = 5.81-6.10 H2O describes the entire range of measured values, with an average composition of CH4??5.99(??0.07) H2O along the equilibrium boundary. These results, consistent with previously measured values, are discussed with respect to the widely ranging values obtained by thermodynamic analysis. The relatively constant composition of methane hydrate over the geologically relevant pressure and temperature range investigated suggests that in situ methane hydrate compositions may be estimated with some confidence. ?? 2005 American Chemical Society.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. Viscosity Measurement of Hydrogen-Methane Mixed Gas for Future Energy Systems

    NASA Astrophysics Data System (ADS)

    Kobayashi, Yohei; Kurokawa, Akira; Hirata, Masaru

    In order to reduce the CO2 emission, in May 2004, the European Union (EU) started an experimental approach known as the “naturalhy Project” in order to transport hydrogen by mixing it with the existing high-pressure natural gas in the pipelines. Naturalhy represents a mixture of hydrogen and natural gas. In other words, this gas is also known as hythane, which is an abbreviation of hydrogen and methane. The name “hythane” is the registered trademark of Hydrogen Consulting Inc., USA. Why will this gas gain importance? It is generally considered that the sudden realization of a hydrogen energy society cannot take place. It is normally assumed that the present status of methane as an energy carrier gradually changes to a state of hydrogen-methane mixed gas and finally to 100% hydrogen. This is why the authors investigate the properties of this mixture. This study is considered to be the first to measure the temperature dependence of the viscosity of hydrogen-methane mixed gas. In order to measure the viscosity, the authors used a capillary method that measures the pressure drop in the laminar flow through a pipe. It was conducted in an electrically polished, ultra clean and smooth tube and the pressure drop between the upstream and downstream was carefully measured using a capacitance manometer. In order to remove the effect of temperature dependence, the tube was placed in a constant temperature bath, and the temperature fluctuation was maintained within ±0.3°C throughout this experimental study. The authors obtained the viscosity of the hydrogen-methane mixed gas within a temperature range of 20-70°C.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Measurements of methane emissions at natural gas production sites in the United States

    PubMed Central

    Allen, David T.; Torres, Vincent M.; Thomas, James; Sullivan, David W.; Harrison, Matthew; Hendler, Al; Herndon, Scott C.; Kolb, Charles E.; Fraser, Matthew P.; Hill, A. Daniel; Lamb, Brian K.; Miskimins, Jennifer; Sawyer, Robert F.; Seinfeld, John H.

    2013-01-01

    Engineering estimates of methane emissions from natural gas production have led to varied projections of national emissions. This work reports direct measurements of methane emissions at 190 onshore natural gas sites in the United States (150 production sites, 27 well completion flowbacks, 9 well unloadings, and 4 workovers). For well completion flowbacks, which clear fractured wells of liquid to allow gas production, methane emissions ranged from 0.01 Mg to 17 Mg (mean = 1.7 Mg; 95% confidence bounds of 0.67–3.3 Mg), compared with an average of 81 Mg per event in the 2011 EPA national emission inventory from April 2013. Emission factors for pneumatic pumps and controllers as well as equipment leaks were both comparable to and higher than estimates in the national inventory. Overall, if emission factors from this work for completion flowbacks, equipment leaks, and pneumatic pumps and controllers are assumed to be representative of national populations and are used to estimate national emissions, total annual emissions from these source categories are calculated to be 957 Gg of methane (with sampling and measurement uncertainties estimated at ±200 Gg). The estimate for comparable source categories in the EPA national inventory is ∼1,200 Gg. Additional measurements of unloadings and workovers are needed to produce national emission estimates for these source categories. The 957 Gg in emissions for completion flowbacks, pneumatics, and equipment leaks, coupled with EPA national inventory estimates for other categories, leads to an estimated 2,300 Gg of methane emissions from natural gas production (0.42% of gross gas production). PMID:24043804

  16. Measurements of methane emissions at natural gas production sites in the United States.

    PubMed

    Allen, David T; Torres, Vincent M; Thomas, James; Sullivan, David W; Harrison, Matthew; Hendler, Al; Herndon, Scott C; Kolb, Charles E; Fraser, Matthew P; Hill, A Daniel; Lamb, Brian K; Miskimins, Jennifer; Sawyer, Robert F; Seinfeld, John H

    2013-10-29

    Engineering estimates of methane emissions from natural gas production have led to varied projections of national emissions. This work reports direct measurements of methane emissions at 190 onshore natural gas sites in the United States (150 production sites, 27 well completion flowbacks, 9 well unloadings, and 4 workovers). For well completion flowbacks, which clear fractured wells of liquid to allow gas production, methane emissions ranged from 0.01 Mg to 17 Mg (mean = 1.7 Mg; 95% confidence bounds of 0.67-3.3 Mg), compared with an average of 81 Mg per event in the 2011 EPA national emission inventory from April 2013. Emission factors for pneumatic pumps and controllers as well as equipment leaks were both comparable to and higher than estimates in the national inventory. Overall, if emission factors from this work for completion flowbacks, equipment leaks, and pneumatic pumps and controllers are assumed to be representative of national populations and are used to estimate national emissions, total annual emissions from these source categories are calculated to be 957 Gg of methane (with sampling and measurement uncertainties estimated at ± 200 Gg). The estimate for comparable source categories in the EPA national inventory is ~1,200 Gg. Additional measurements of unloadings and workovers are needed to produce national emission estimates for these source categories. The 957 Gg in emissions for completion flowbacks, pneumatics, and equipment leaks, coupled with EPA national inventory estimates for other categories, leads to an estimated 2,300 Gg of methane emissions from natural gas production (0.42% of gross gas production).

  17. Mapping methane from marine and terrestrial hydrocarbon seepage using AVIRIS

    NASA Astrophysics Data System (ADS)

    Thorpe, A. K.; Bradley, E. S.; Funk, C.; Roberts, D. A.; Leifer, I.; Dennison, P. E.; Margolis, J.

    2010-12-01

    Concentrations of atmospheric methane (CH4), a greenhouse gas at least 20 times more potent per molecule than carbon dioxide (CO2), have more than doubled in the last two centuries. Due to a lack of direct measurements of sources and sinks, the global methane budget is poorly constrained and emissions of this important greenhouse gas are often underestimated in climate models. The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) recently mapped methane emissions from the Coal Oil Point (COP) marine seep fields, a concentrated geologic methane source (0.015 Tg yr-1 from ~3 km2) located offshore from Santa Barbara, CA using a residual-based approach (Roberts et al. 2010) and short-wave infrared band ratios (Bradley et al. submitted). In this study, an additional cluster-tuned matched filter technique adapted from Funk et al. 2001 detected methane anomalies for COP that closely matched previous results and were in agreement with sonar-based seep surveys and flux buoy data. This technique was also applied to AVIRIS data acquired over the La Brea Tar Pits in Los Angeles, CA, a region known for natural oil and methane seepage. Significant anomalies were identified for known methane sources close to the tar pits where pipes have been established to prevent dangerous methane buildup. Therefore, imaging spectrometry using sensors like AVIRIS and planned satellite sensors like HyspIRI has the potential to greatly improve high spatial resolution mapping of methane emissions, thereby better constraining regional methane sources.

  18. 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

  19. Measurements of methane and carbon dioxide fluxes on the Bakchar bog in warm season

    NASA Astrophysics Data System (ADS)

    Krasnov, Oleg A.; Maksyutov, Shamil S.; Davydov, Denis K.; Fofonov, Aleksander V.; Glagolev, Mikhail V.

    2015-11-01

    Data terrain-atmosphere fluxes of methane and carbon dioxide overseen for measurement campaign Plotnikovo-2014 on the bog's Flux-NIES automatic complex (N56°51.29' E82° 50.91') in the warn season. Six vegetative groups on the bog's surface were taken in comparison. Improvement precise method used to determinate the sensitivity for the gases analyzers and calculating of the CO2 and CH4 fluxes measured by automated chamber-based technique.

  20. Methane emission from naturally ventilated livestock buildings can be determined from gas concentration measurements.

    PubMed

    Bjerg, Bjarne; Zhang, Guoqiang; Madsen, Jørgen; Rom, Hans B

    2012-10-01

    Determination of emission of contaminant gases as ammonia, methane, or laughing gas from natural ventilated livestock buildings with large opening is a challenge due to the large variations in gas concentration and air velocity in the openings. The close relation between calculated animal heat production and the carbon dioxide production from the animals have in several cases been utilized for estimation of the ventilation air exchange rate for the estimation of ammonia and greenhouse gas emissions. Using this method, the problem of the complicated air velocity and concentration distribution in the openings is avoided; however, there are still some important issues remained unanswered: (1) the precision of the estimations, (2) the requirement for the length of measuring periods, and (3) the required measuring point number and location. The purpose of this work was to investigate how estimated average gas emission and the precision of the estimation are influenced by different calculation procedures, measuring period length, measure point locations, measure point numbers, and criteria for excluding measuring data. The analyses were based on existing data from a 6-day measuring period in a naturally ventilated, 150 milking cow building. The results showed that the methane emission can be determined with much higher precision than ammonia or laughing gas emissions, and, for methane, relatively precise estimations can be based on measure periods as short as 3 h. This result makes it feasible to investigate the influence of feed composition on methane emission in a relative large number of operating cattle buildings and consequently it can support a development towards reduced greenhouse gas emission from cattle production.

  1. 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.

  2. 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.

  3. Measuring In situ Dissolved Methane Concentrations in Gas Hydrate-Rich Systems. Part 2: Investigating Mechanisms Controlling Hydrate Dissolution

    NASA Astrophysics Data System (ADS)

    Wilson, R. M.; Lapham, L.; Riedel, M.; Chanton, J.

    2010-12-01

    Methane is a potent greenhouse gas, twenty times more infrared-active than CO2, and an important energy source. For these reasons, methane hydrate, one of the largest potential reservoirs of methane on earth, is of considerable interest to scientists and industry alike. In particular, questions relating to the stability of methane hydrate are becoming more important as concern about the release of methane into overlying ocean (and eventually the atmosphere) and interest in the recovery of methane from this resource increase. Three primary factors control hydrate stability: pressure (P), temperature (T), and the gas concentration in the surrounding environment. Pressure and temperature govern the stability of the hydrate structure. When hydrate is exposed to P/T regimes outside of the stability zone (HSZ), the hydrate decomposes by dissociation, a relatively fast process resulting in the release of gaseous phase methane (CH4(g)). However, if the P/T regime is within the HSZ, but the concentration of the guest gas (typically CH4) in the surroundings is below saturation, the hydrate will decompose by dissolution resulting in a phase change between hydrate and the dissolved gas phase (CH4(aq)). OsmoSamplers were deployed at a methane hydrate outcrop in Barkley Canyon, Northern Cascadia Margin, collecting porewater samples in a gradient at 1cm increments away from the hydrate surface. Methane, ethane, and propane concentrations in the porewater samples were measured at 6-day resolution over a period of 9 months. At three centimeters from the hydrate face, methane concentrations were significantly lower than predicted saturation for conditions at this site. Curiously, in situ observations of natural hydrate dissolution are up to two orders of magnitude lower than predicted diffusion-controlled dissolution based on surrounding methane concentrations. Since diffusion of methane away from the hydrate surface has been implicated as the dominant control of hydrate dissolution

  4. Fast Methane Measurements Using a Novel Laser-based Gas Analyzer

    NASA Astrophysics Data System (ADS)

    Baer, D.; Gupta, M.; Owano, T.; Provencal, R.; Ricci, K.; O'Keefe, A.

    2005-12-01

    Methane has increased significantly with human population levels. Pre-1750 ice core data indicates that pre-industrialization levels were ~700 ppbv, while current levels are ~1745 ppbv. In current budget estimates of atmospheric CH4, major contributors include both natural (wetlands) and anthropogenic sources (energy, landfills, ruminants, biomass burning, rice agriculture). The strengths of these sources vary spatially and temporally. Estimates of emissions from wetlands are also uncertain due to the extreme variability of these ecosystems. Because methane lifetime is relatively long (8.4 years), atmospheric variations in concentration are small and accuracy in measurement is important for understanding spatial and temporal variability. We report on the application and independent performance characterization of a novel gas analyzer based on cavity-enhanced laser absorption spectroscopy. The Analyzer was used for the measurements of methane in ambient air for eddy correlation flux measurements and for chamber flux measurements. The Analyzer provided continuous measurements at data rates up to 20 Hz and a replicate precision of better than 2 ppbv in a 1 second measurement time.

  5. Real-Time Measurements of Ethane for Source Attribution of Methane Plumes from Oil and Gas Facilities

    NASA Astrophysics Data System (ADS)

    Yacovitch, T. I.; Floerchinger, C.; Roscioli, J. R.; Herndon, S.; Fortner, E.; Knighton, W. B.; Petron, G.; Sweeney, C.; Karion, A.; Kofler, J.; Iglesias, G.; Zavala, M. A.; Molina, L. T.

    2013-12-01

    The Aerodyne Mobile Lab has conducted several recent studies of the methane emissions from Oil and Gas facilities at varying stages of production: well-heads; processing facilities; and compressor stations. Accurate quantification of methane emission rates are can be complicated by other local sources, notably livestock and microbial production. Methane emissions from oil and gas facilities are always accompanied by small amounts of ethane, while biogenic plumes contain no ethane. A prototype ethane spectrometer based on the Aerodyne-Mini chassis, has been deployed to oil and gas facilities in the Veracruz region of Mexico, as part of the 2013 Short-Lived Climate-Forcing project, and during ground-based measurements in the Barnett Shale in Texas as part of the Barnett Oil and Gas Observation Study. These results suggest a source-dependence in the ethane-to-methane ratio in oil and gas emissions. The results will be contrasted with 13CH4 methane isotope ratios determined using Aerodyne's Methane-Dual instrument. The limits and advantages of ethane-methane ratios and methane isotopes will be discussed. In the current instrumentation, the precision of determined ethane-to-methane ratios in a single plume encounter exceeds the analogous carbon isotope quantification.

  6. Fourier Transform Spectrometer measurements of Atmospheric Carbon Dioxide and Methane

    NASA Astrophysics Data System (ADS)

    Kivi, Rigel; Heikkinen, Pauli; Chen, Huilin; Hatakka, Juha; Laurila, Tuomas

    2016-04-01

    Ground based remote sensing measurements of column CO2 and CH4 using Fourier Transform Spectrometers (FTS) within the Total Carbon Column Observing Network (TCCON) are known for high precision and accuracy. These measurements are performed at various locations globally and they have been widely used in carbon cycle studies and validation of space born measurements. The relevant satellite missions include the Orbiting Carbon Observatory-2 (OCO-2) by the National Aeronautics and Space Administration (NASA); the SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY) by the European Space Agency (ESA); the Greenhouse gases Observing SATellite (GOSAT) by the Japan Aerospace Exploration Agency (JAXA) and the upcoming Sentinel-5 Precursor mission, which is an ESA mission and scheduled for launch in 2016. Results of the column CO2 and CH4 measurements at Sodankylä in northern Finland (at 67.4° N, 26.6° E) are reported in this study. The measurements have been performed on regular basis since the beginning of the program in early 2009. We also present evaluation of the data quality of the ground based measurements and comparisons with the available satellite based retrievals. In case of comparisons between the GOSAT and ground based retrievals of CO2 and CH4 no significant biases were found. Sodankylä is one of the northernmost stations in the TCCON network. However, the data coverage has been relatively good thanks to the progress towards automation of the FTS measurement system. At Sodankylä the retrievals have been also compared with the balloon borne AirCore measurements at the site. AirCore sampling system is directly related to the World Meteorological Organization in situ trace gas measurement scales. The balloon platform allows sampling in both stratosphere and troposphere, which is a benefit, compared to the aircraft in situ measurements.

  7. Atmospheric methane measurement instrument using a Zeeman-split He-Ne laser

    NASA Technical Reports Server (NTRS)

    Mcmanus, J. Barry; Kebabian, Paul L.; Kolb, Charles E.

    1989-01-01

    The construction of an atmospheric methane measurement instrument based on a Zeeman-split IR He-Ne laser is reported. The laser has a tranverse magnetic field over about 2/3 of its gain length and can oscillate at an (unsplit) frequency (2947.91/cm) centered on a methane absorption line, or on either of two frequencies split by + or - 0.055/cm from the center, with low CH4 absorption. The laser is tuned to dwell sequentially at each frequency, giving two differential absorption measurements in each 46-ms tuning cycle. Atmospheric measurements are made using two multiple pass absorption cells, one with fast (0.75-s) and one with slow (5-s) flow response times. Fluctuations in ambient CH4 of about 20-ppb (rms, 1-s averaging) are detected, with interference fringe effects the dominant noise source. The instrument has operated in a field experiment (NASA GTE/ABLE-3A) in Alaska.

  8. Mobile Methane Measurements of Natural Gas Distribution and End-use Emissions in Indianapolis

    NASA Astrophysics Data System (ADS)

    Lamb, B. K.; Roscioli, J. R.; Floerchinger, C. R.; Herndon, S. C.; Ferrara, T.

    2015-12-01

    Indianapolis is the site of the INFLUX program to investigate greenhouse gas emissions from a large metropolitan area. A key question in INFLUX is the relative contributions of methane emissions from the local gas distribution system in comparison to biogenic sources, such as the wastewater treatment system and landfills, and of end use emissions from furnaces and other combustion devices downstream of customer gas meters. During February and March, 2015, the Aerodyne van was used to measure methane, ethane, CO2 and other trace gases during mobile sampling traverses through a number of urban and suburban Indianapolis neighborhoods. Signatures of distinct natural gas emissions, biogenic emissions, and combustion emissions were observed in small plumes. In a number of cases, these sources were identified as manhole covers in city streets, where nearby leaks can seep into the local wastewater system. Quantification of ethane and methane from 45 manholes reveal that some had emissions that were clearly biogenic while others had a distinct natural gas signature. This paper describes the results from the analysis of these mobile data in the context of the current Indianapolis methane emission inventory.

  9. Measurement of the first Townsend ionization coefficient in a methane-based tissue-equivalent gas

    NASA Astrophysics Data System (ADS)

    Petri, A. R.; Gonçalves, J. A. C.; Mangiarotti, A.; Botelho, S.; Bueno, C. C.

    2017-03-01

    Tissue-equivalent gases (TEGs), often made of a hydrocarbon, nitrogen, and carbon dioxide, have been employed in microdosimetry for decades. However, data on the first Townsend ionization coefficient (α) in such mixtures are scarce, regardless of the chosen hydrocarbon. In this context, measurements of α in a methane-based tissue-equivalent gas (CH4 - 64.4%, CO2 - 32.4%, and N2 - 3.2%) were performed in a uniform field configuration for density-normalized electric fields (E/N) up to 290 Td. The setup adopted in our previous works was improved for operating at low pressures. The modifications introduced in the apparatus and the experimental technique were validated by comparing our results of the first Townsend ionization coefficient in nitrogen, carbon dioxide, and methane with those from the literature and Magboltz simulations. The behavior of α in the methane-based TEG was consistent with that observed for pure methane. All the experimental results are included in tabular form in the Supplementary material.

  10. [Measurement of methane and carbon dioxide emissions from ruminants based on the NDIR technique].

    PubMed

    Ding, Xue-Zhi; Long, Rui-Jun; Mi, Jian-Dui; Guo, Xu-Sheng

    2010-06-01

    Methane (CH4) production in the rumen represents a loss of energy for the host animal; in addition, methane eructated by ruminants may contribute to a greenhouse effect or global warming. The dinumal CH4 and carbon dioxide (CO2) emissions from sheep were continuously recorded using the flow-through chamber method. A type new type of non-disperse infrared (NDIR) gas sensors based on pulse IR source was introduced, and by using the high performance pyroelectric IR sensor with built in interference filter and the "single light and two wavelengths" technology, CH4 and CO2 measurement from ruminants was achieved. Animals were given dry oat hay as the basic diet and supplemented concentrate with the ratio of 7 : 3. The results showed that the recovery was 96.7% and 96.2% for CH4 and CO2, respectively. Methane and carbon dioxide output from sheep respectively averaged 15.6 g per day and 184.7 g per day, equivalent to 6.8 and 71.1 kg per animal. Diurnal fluctuations in hourly rates of CH4 and CO2 production in hourly of methane increased during day light to reach a peak at or near sunset and then declined towards sunrise, and consideration was given to the dry matter intake of the animals used in these studies and its possible effects on CH4 production.

  11. Remote sensing and in situ measurements of methane and ammonia emissions from a megacity dairy complex: Chino, CA.

    PubMed

    Leifer, Ira; Melton, Christopher; Tratt, David M; Buckland, Kerry N; Clarisse, Lieven; Coheur, Pierre; Frash, Jason; Gupta, Manish; Johnson, Patrick D; Leen, J Brian; Van Damme, Martin; Whitburn, Simon; Yurganov, Leonid

    2017-02-01

    Methane (CH4) and ammonia (NH3) directly and indirectly affect the atmospheric radiative balance with the latter leading to aerosol generation. Both have important spectral features in the Thermal InfraRed (TIR) that can be studied by remote sensing, with NH3 allowing discrimination of husbandry from other CH4 sources. Airborne hyperspectral imagery was collected for the Chino Dairy Complex in the Los Angeles Basin as well as in situ CH4, carbon dioxide (CO2) and NH3 data. TIR data showed good spatial agreement with in situ measurements and showed significant emissions heterogeneity between dairies. Airborne remote sensing mapped plume transport for ∼20 km downwind, documenting topographic effects on plume advection. Repeated multiple gas in situ measurements showed that emissions were persistent on half-year timescales. Inversion of one dairy plume found annual emissions of 4.1 × 10(5) kg CH4, 2.2 × 10(5) kg NH3, and 2.3 × 10(7) kg CO2, suggesting 2300, 4000, and 2100 head of cattle, respectively, and Chino Dairy Complex emissions of 42 Gg CH4 and 8.4 Gg NH3 implying ∼200k cows, ∼30% more than Peischl et al. (2013) estimated for June 2010. Far-field data showed chemical conversion and/or deposition of Chino NH3 occurs within the confines of the Los Angeles Basin on a four to six h timescale, faster than most published rates, and likely from higher Los Angeles oxidant loads. Satellite observations from 2011 to 2014 confirmed that observed in situ transport patterns were representative and suggests much of the Chino Dairy Complex emissions are driven towards eastern Orange County, with a lesser amount transported to Palm Springs, CA. Given interest in mitigating husbandry health impacts from air pollution emissions, this study highlights how satellite observations can be leveraged to understand exposure and how multiple gas in situ emissions studies can inform on best practices given that emissions reduction of one gas could increase those of

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. RUSALKA experiment to measure carbon dioxide and methane from ISS

    NASA Astrophysics Data System (ADS)

    Korablev, O.

    2009-04-01

    RUSALKA experiment aimed to demonstrate the method to monitor CO2 and CH4 is now prepared for the Russian segment of the International Space Station (ISS). Hardware will be delivered to ISS in March 2009. The novel instrument is a high-resolution near-IR spectrometer combining an echelle grating with an acousto-optic tunable filter (AOTF) for separation of diffraction orders. A compact design with no moving parts within the mass budget of 2 kg allows to reach the resolving power of 10000-20000 in the spectral ranges of 1580 nm (CO2), 1640 nm (CH4), in 49 and 47 diffraction orders, and of reference O2 bands 760 and 1270 nm, in 101 and 61 diffraction orders. Only one diffraction order can be measured at a time, but thanks to flexibility of the AOTF tuning, any order can be measured randomly and rapidly within the spectral range. A spectrometer, based on this principle, SOIR (Solar Occultation InfraRed) is operational on Venus Express ESA mission since 2005. RUSALKA investigation targets precision measurements of CO2 and CH4 integral quantities, in nadir/oblique or observing solar glint over the water surfaces. Test measurements are also planned in solar occultation mode. Battery-powered RUSALKA package consists of the spectrometer itself, standard photographic camera for context imaging, and adapters. Measurements will be performed by crew members pointing manually the target areas. Such measurements from ISS will allow to verify the method to be used in the future on different satellite platforms. The small size of the instrument makes it ideal for micro-satellites, capable to provide necessary pointing for glint or solar occultation observations. The status and calibration of RUSALKA flight hardware will be discussed.

  1. RUSALKA experiment to measure carbon dioxide and methane from ISS

    NASA Astrophysics Data System (ADS)

    Korablev, Oleg; Trokhimovskiy, Alexander; Vinogradov, Imant; Fedorova, Anna; Ivanov, Andrei; Rodin, Alexander; Smirnov, Yurii

    2010-05-01

    RUSALKA is an experiment aimed to demonstrate the method to monitor CO2 and CH4 with low cost and weight equipment. It was delivered to the Russian segment of the International Space Station (ISS) in the end of summer 2009. The novel instrument is a high-resolution near-IR spectrometer combining an echelle grating with an acousto-optic tunable filter (AOTF) for separation of diffraction orders. A compact design with no moving parts within the mass budget of 2 kg allows to reach the resolving power of 20000 in the spectral range of 1580 nm (CO2), 1640 nm (CH4), in 49 and 47 echelle grating diffraction orders, and of reference O2 bands 760 and 1270 nm, in 101 and 61 diffraction orders. Only one diffraction order can be measured at a time, but thanks to flexibility of the AOTF tuning, any order can be measured randomly and rapidly within the spectral range. A spectrometer, based on this principle, SOIR (Solar Occultation InfraRed) is operational on Venus Express ESA mission since 2005. RUSALKA investigation targets precision measurements of CO2 and CH4 integral quantities, in nadir/oblique or observing solar glint over the water surfaces. Test measurements are also planned in solar occultation mode. Battery-powered RUSALKA package consists of the spectrometer itself, standard photographic camera for context imaging, and adapters. Measurements are performed by crew members pointing manually the target areas. Such measurements from ISS allow to verify methods used on different satellite platforms. The small size of the instrument makes it ideal for micro-satellites, capable to provide necessary pointing for glint or solar occultation observations. By the end of year 2009 all technical and organizing problems were solved and first datasets (high resolution spectra and exact ISS position data) where acquired for further processing.

  2. Uncertainties in the national inventory of methane emissions from rice cultivation: field measurements and modeling approaches

    NASA Astrophysics Data System (ADS)

    Zhang, Wen; Sun, Wenjuan; Li, Tingting

    2017-01-01

    Uncertainties in national inventories originate from a variety of sources, including methodological failures, errors, and insufficiency of supporting data. In this study, we analyzed these sources and their contribution to uncertainty in the national inventory of rice paddy methane emissions in China and compared the differences in the approaches used (e.g., direct measurements, simple regressions, and more complicated models). For the 495 field measurements we collected from the scientific literature, the area-weighted 95 % CI (confidence interval) ranged from 13.7 to 1115.4 kg CH4 ha-1, and the histogram distribution of the measurements agreed well with parameterized gamma distributions. For the models, we compared the performance of methods of different complexity (i.e., the CH4MOD model, representing a complicated method, and two less complex statistical regression models taken from literature) to evaluate the uncertainties associated with model performance as well as the quality and accessibility of the regional datasets. Comparisons revealed that the CH4MOD model may perform worse than the comparatively simple regression models when no sufficient input data for the model is available. As simulated by CH4MOD with data of irrigation, organic matter incorporation, and soil properties of rice paddies, the modeling methane fluxes varied from 17.2 to 708.3 kg CH4 ha-1, covering 63 % of the range of the field measurements. When applying the modeling approach to the 10 km × 10 km gridded dataset of the model input variables, the within-grid variations, made via the Monte Carlo method, were found to be 81.2-95.5 % of the grid means. Upscaling the grid estimates to the national inventory, the total methane emission from the rice paddies was 6.43 (3.79-9.77) Tg. The fallacy of CH4MOD contributed 56.6 % of the total uncertainty, with the remaining 43.4 % being attributed to errors and the scarcity of the spatial datasets of the model inputs. Our analysis reveals the

  3. Methane and nitrous oxide measurements onboard the UK Atmospheric Research Aircraft using quantum cascade laser spectrometry (QCL)

    NASA Astrophysics Data System (ADS)

    Muller, J. B.; O'Shea, S.; Dorsey, J.; Bauguitte, S.; Cain, M.; Allen, G.; Percival, C. J.; Gallagher, M. W.

    2012-12-01

    A Aerodyne Research© Mini-Quantum Cascade Laser (QCL) spectrometer was installed on the UK Facility of Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft and employed during summer 2012. Methane (CH4) and nitrous oxide (N2O) concentrations were measured within the Arctic Circle as part of the MAMM project (Methane and other greenhouse gases in the Arctic - Measurements, process studies and Modelling) as well as around the UK as part of the ClearfLo project (Clean Air for London). A range of missions were flown, including deep vertical profiles up to the stratosphere, providing concentration profiles of CH4 and N2O, as well as low altitude level runs exploring near surface diffuse emission sources such as the wetlands in Arctic Lapland and point emissions sources such as gas platforms off the UK coast. Significant pollution plumes were observed both in the Arctic and around the UK with elevated CH4 concentrations, as well as enhanced CO, O3 and aerosol levels. The NAME Lagrangian particle dispersion model will be used to investigate the origins of these CH4 plumes to identify the locations of the emissions sources. The first set of flights using QCL on the FAAM research aircraft have been successful and regular in-flight calibrations (high/low span) and target concentrations were used to determine instrument accuracy and precision. Additional data quality control checks could be made by comparison with an onboard Los Gatos Fast Greenhouse Gas Analyser (FGGA) for CO2 and CH4 and provide the basis for further instrument development and implementation for future Arctic MAMM flights during spring and summer 2013.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. Direct measurements show decreasing methane emissions from natural gas local distribution systems in the United States.

    PubMed

    Lamb, Brian K; Edburg, Steven L; Ferrara, Thomas W; Howard, Touché; Harrison, Matthew R; Kolb, Charles E; Townsend-Small, Amy; Dyck, Wesley; Possolo, Antonio; Whetstone, James R

    2015-04-21

    Fugitive losses from natural gas distribution systems are a significant source of anthropogenic methane. Here, we report on a national sampling program to measure methane emissions from 13 urban distribution systems across the U.S. Emission factors were derived from direct measurements at 230 underground pipeline leaks and 229 metering and regulating facilities using stratified random sampling. When these new emission factors are combined with estimates for customer meters, maintenance, and upsets, and current pipeline miles and numbers of facilities, the total estimate is 393 Gg/yr with a 95% upper confidence limit of 854 Gg/yr (0.10% to 0.22% of the methane delivered nationwide). This fraction includes emissions from city gates to the customer meter, but does not include other urban sources or those downstream of customer meters. The upper confidence limit accounts for the skewed distribution of measurements, where a few large emitters accounted for most of the emissions. This emission estimate is 36% to 70% less than the 2011 EPA inventory, (based largely on 1990s emission data), and reflects significant upgrades at metering and regulating stations, improvements in leak detection and maintenance activities, as well as potential effects from differences in methodologies between the two studies.

  10. Static chamber methane flux measurements in volcanic/geothermal areas: preliminary data from Sousaki and Nisyros (Greece)

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Walter; Fiebig, Jens; Konstantinos, Kyriakopoulos; Brusca, Lorenzo; Maneta, Victoria; Michas, Giorgios; Papadakis, Giorgios

    2010-05-01

    Methane plays an important role in the Earth's atmospheric chemistry and radiative balance being the second most important greenhouse gas after carbon dioxide. Methane is released to the atmosphere by a wide number of sources, both natural and anthropogenic, with the latter being twice as large as the former (IPCC, 2007). It has recently been established that significant amounts of geological methane, produced within the Earth's crust, are currently released naturally into the atmosphere (Etiope, 2004). Active or recent volcanic/geothermal areas represent one of these sources of geological methane. But due to the fact that methane flux measurements are laboratory intensive, very few data have been collected until now and the contribution of this source has been generally indirectly estimated (Etiope et al., 2007). The Greek territory is geodynamically very active and has many volcanic and geothermal areas. Here we report on methane flux measurements made at two volcanic/geothermal systems along the South Aegean volcanic arc: Sousaki and Nisyros. The former is an extinct volcanic area of Plio-Pleistocene age hosting nowadays a low enthalpy geothermal field. The latter is a currently quiescent active volcanic system with strong fumarolic activity due to the presence of a high enthalpy geothermal system. Both systems have gas manifestations that emit significant amounts of hydrothermal methane and display important diffuse carbon dioxide emissions from the soils. New data on methane isotopic composition and higher hydrocarbon contents point to an abiogenic origin of the hydrothermal methane in the studied systems. Measured methane flux values range from -48 to 29,000 (38 sites) and from -20 to 1100 mg/m^2/d (35 sites) at Sousaki and Nisyros respectively. At Sousaki measurement sites covered almost all the degassing area and the diffuse methane output can be estimated in about 20 t/a from a surface of about 10,000 m^2. At Nisyros measurements covered the Stephanos and

  11. Measuring in situ dissolved methane concentrations in gas hydrate-rich systems, Part 1: Investigating the correlation between tectonics and methane release from sediments

    NASA Astrophysics Data System (ADS)

    Lapham, L.; Wilson, R. M.; Paull, C. K.; Chanton, J.; Riedel, M.

    2010-12-01

    In 2009, an area of extended methane venting at 1200 meters water depth was found with high resolution AUV bathymetry scans on the Northern Cascadia Margin that was previously unknown. When visited by ROV, we found seafloor cracks with active bubble streams and thin bacterial mats suggesting shallow gas and possible pore-fluid saturation. Upon coring into the cracks, a hard-substrate (carbonate or gas hydrate) was punctured and gas flows began. With these observations, we asked the question “is this shallow gas released from the seafloor from regional tectonic activity, and, if so, what is the temporal variability of such release events?” To answer this, we deployed a long term pore-water collection device at one of these gas crack sites, informally named “bubbly gulch”, for 9 months. The device is made up of 4 OsmoSamplers that were each plumbed to a port along a 1-meter probe tip using small diameter tubing. By osmosis, the samplers collected water samples slowly through the ports and maintained them within a 300 meter-long copper tubing coil. Because of the high methane concentrations anticipated, in situ pressures were maintained within the coil by the addition of a high pressure valve. Water samples were collected from the overlying water, at the sediment-water interface, and 6 and 10 cm into the sediments. Bottom water temperatures were also measured over the time series to determine pumping rates of the samplers but also to look for any temporal variability. In May 2010, the samplers were retrieved by ROV during efforts to install seafloor instruments for Neptune Canada. In a land-based lab, the coils were sub-sampled by cutting every 4 meters of tubing. With a pumping rate of 0.5 mL/day, this allowed a temporal resolution of 6 days. To date, one sampler coil has been sub-sampled and measured for methane concentrations and stable carbon isotopes. Preliminary results from this coil show pore-fluids nearly saturated with respect to methane, ~45 m

  12. Application of a methane carbon isotope analyzer for the investigation of δ13C of methane emission measured by the automatic chamber method in an Arctic Tundra

    NASA Astrophysics Data System (ADS)

    Mastepanov, Mikhail; Christensen, Torben

    2014-05-01

    Methane emissions have been monitored by an automatic chamber method in Zackenberg valley, NE Greenland, since 2006 as a part of Greenland Ecosystem Monitoring (GEM) program. During most of the seasons the measurements were carried out from the time of snow melt (June-July) until freezing of the active layer (October-November). Several years of data, obtained by the same method, instrumentation and at exactly the same site, provided a unique opportunity for the analysis of interannual methane flux patterns and factors affecting their temporal variability. The start of the growing season emissions was found to be closely related to a date of snow melt at the site. Despite a large between year variability of this date (sometimes more than a month), methane emission started within a few days after, and was increasing for the next about 30 days. After this peak of emission, it slowly decreased and stayed more or less constant or slightly decreasing during the rest of the growing season (Mastepanov et al., Biogeosciences, 2013). During the soil freezing, a second peak of methane emission was found (Mastepanov et al., Nature, 2008); its amplitude varied a lot between the years, from almost undetectable to comparable with total growing season emissions. Analysis of the multiyear emission patterns (Mastepanov et al., Biogeosciences, 2013) led to hypotheses of different sources for the spring, summer and autumn methane emissions, and multiyear cycles of accumulation and release of these components to the atmosphere. For the further investigation of this it was decided to complement the monitoring system with a methane carbon isotope analyzer (Los Gatos Research, USA). The instrument was installed during 2013 field season and was successfully operating until the end of the measurement campaign (27 October). Detecting both 12C-CH4 and 13C-CH4 concentrations in real time (0.5 Hz) during automatic chamber closure (15 min), the instrument was providing data for determination of

  13. Stream measurements locate thermogenic methane fluxes in groundwater discharge in an area of shale-gas development.

    PubMed

    Heilweil, Victor M; Grieve, Paul L; Hynek, Scott A; Brantley, Susan L; Solomon, D Kip; Risser, Dennis W

    2015-04-07

    The environmental impacts of shale-gas development on water resources, including methane migration to shallow groundwater, have been difficult to assess. Monitoring around gas wells is generally limited to domestic water-supply wells, which often are not situated along predominant groundwater flow paths. A new concept is tested here: combining stream hydrocarbon and noble-gas measurements with reach mass-balance modeling to estimate thermogenic methane concentrations and fluxes in groundwater discharging to streams and to constrain methane sources. In the Marcellus Formation shale-gas play of northern Pennsylvania (U.S.A.), we sampled methane in 15 streams as a reconnaissance tool to locate methane-laden groundwater discharge: concentrations up to 69 μg L(-1) were observed, with four streams ≥ 5 μg L(-1). Geochemical analyses of water from one stream with high methane (Sugar Run, Lycoming County) were consistent with Middle Devonian gases. After sampling was completed, we learned of a state regulator investigation of stray-gas migration from a nearby Marcellus Formation gas well. Modeling indicates a groundwater thermogenic methane flux of about 0.5 kg d(-1) discharging into Sugar Run, possibly from this fugitive gas source. Since flow paths often coalesce into gaining streams, stream methane monitoring provides the first watershed-scale method to assess groundwater contamination from shale-gas development.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Quantification of Fugitive Methane Emissions with Spatially Correlated Measurements Collected with Novel Plume Camera

    NASA Astrophysics Data System (ADS)

    Tsai, Tracy; Rella, Chris; Crosson, Eric

    2013-04-01

    Quantification of fugitive methane emissions from unconventional natural gas (i.e. shale gas, tight sand gas, etc.) production, processing, and transport is essential for scientists, policy-makers, and the energy industry, because methane has a global warming potential of at least 21 times that of carbon dioxide over a span of 100 years [1]. Therefore, fugitive emissions reduce any environmental benefits to using natural gas instead of traditional fossil fuels [2]. Current measurement techniques involve first locating all the possible leaks and then measuring the emission of each leak. This technique is a painstaking and slow process that cannot be scaled up to the large size of the natural gas industry in which there are at least half a million natural gas wells in the United States alone [3]. An alternative method is to calculate the emission of a plume through dispersion modeling. This method is a scalable approach since all the individual leaks within a natural gas facility can be aggregated into a single plume measurement. However, plume dispersion modeling requires additional knowledge of the distance to the source, atmospheric turbulence, and local topography, and it is a mathematically intensive process. Therefore, there is a need for an instrument capable of simple, rapid, and accurate measurements of fugitive methane emissions on a per well head scale. We will present the "plume camera" instrument, which simultaneously measures methane at different spatial points or pixels. The spatial correlation between methane measurements provides spatial information of the plume, and in addition to the wind measurement collected with a sonic anemometer, the flux can be determined. Unlike the plume dispersion model, this approach does not require knowledge of the distance to the source and atmospheric conditions. Moreover, the instrument can fit inside a standard car such that emission measurements can be performed on a per well head basis. In a controlled experiment

  2. 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.

  3. 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.

  4. 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

  5. Methane fluxes measured by eddy covariance at a temperate upland forest

    NASA Astrophysics Data System (ADS)

    Wang, J.; Murphy, J. G.; Winsborough, C. L.; Basiliko, N.; Geddes, J. A.; Thomas, S.

    2012-12-01

    Methane flux measurements were carried out at a temperate upland forest in Central Ontario, Haliburton Forest and Wildlife Reserve (45.28° N, 78.55° W) using the eddy covariance (EC) method. An off-axis integrated cavity output spectrometer (OA-ICOS) Fast Greenhouse Gas Analyzer (FGGA from Los Gatos Research, Inc.) operated at a sampling rate of 10 Hz allowed for simultaneous measurement of methane (CH4), carbon dioxide (CO2), and water (H2O) over five months from June to October in 2011. Air was pulled from the top of a 32 m tower, 8 m above the forest canopy, to the bottom of the tower through 40 m of tubing to the instrument. A sonic anemometer and a LI-7500 open-path sensor were also used at the top of the tower to provide high frequency wind data and comparative open-path measurements of CO2 and H2O. A nearby soil station measured soil water content and soil temperature at 0, 3, and 10 cm below the surface. Observed methane fluxes showed net uptake of CH4 over the measurement period with an average uptake flux value (± standard deviation of the mean) of -2.7±0.13 nmol m-2 s-1. In early June when measurements commenced, the soil moisture was relatively high and CH4 flux values showed net emission. As the season advanced the soil became progressively drier, and there was an increasing trend in CH4 uptake, peaking in mid-September. There was also a diurnal trend in the CH4 flux, with increased uptake during the day, and decreased uptake between 0:00 and 08:00. The CH4 flux values correlated well with the horizontal wind speed measured within the forest canopy. We hypothesize that this may be due to a ventilation effect in which higher wind speed facilitates the introduction of CH4-rich air and removes CH4-depleted air near the methanotrophs in the soil. The measurements were made in an uneven-aged managed forest stand last harvested 15 years ago containing sandy and acidic soils (pH 4.0 - 5.0). Chamber flux measurements of CH4 were also performed at seven

  6. Use of short-term breath measures to estimate daily methane production by cattle.

    PubMed

    Velazco, J I; Mayer, D G; Zimmerman, S; Hegarty, R S

    2016-01-01

    Methods to measure enteric methane (CH4) emissions from individual ruminants in their production environment are required to validate emission inventories and verify mitigation claims. Estimates of daily methane production (DMP) based on consolidated short-term emission measurements are developing, but method verification is required. Two cattle experiments were undertaken to test the hypothesis that DMP estimated by averaging multiple short-term breath measures of methane emission rate did not differ from DMP measured in respiration chambers (RC). Short-term emission rates were obtained from a GreenFeed Emissions Monitoring (GEM) unit, which measured emission rate while cattle consumed a dispensed supplement. In experiment 1 (Expt. 1), four non-lactating cattle (LW=518 kg) were adapted for 18 days then measured for six consecutive periods. Each period consisted of 2 days of ad libitum intake and GEM emission measurement followed by 1 day in the RC. A prototype GEM unit releasing water as an attractant (GEM water) was also evaluated in Expt. 1. Experiment 2 (Expt. 2) was a larger study based on similar design with 10 cattle (LW=365 kg), adapted for 21 days and GEM measurement was extended to 3 days in each of the six periods. In Expt. 1, there was no difference in DMP estimated by the GEM unit relative to the RC (209.7 v. 215.1 g CH(4)/day) and no difference between these methods in methane yield (MY, 22.7 v. 23.7 g CH(4)/kg of dry matter intake, DMI). In Expt. 2, the correlation between GEM and RC measures of DMP and MY were assessed using 95% confidence intervals, with no difference in DMP or MY between methods and high correlations between GEM and RC measures for DMP (r=0.85; 215 v. 198 g CH(4)/day SEM=3.0) and for MY (r=0.60; 23.8 v. 22.1 g CH(4)/kg DMI SEM=0.42). When data from both experiments was combined neither DMP nor MY differed between GEM- and RC-based measures (P>0.05). GEM water-based estimates of DMP and MY were lower than RC and GEM (P<0

  7. Remote Sensing and Sea-Truth Measurements of Methane Flux to the Atmosphere (HYFLUX project)

    SciTech Connect

    Ian MacDonald

    2011-05-31

    , respectively. Based on the contemporaneous wind speeds at this site, contemporary estimates of the diffusive fluxes from the mixed layer to the atmosphere for methane, ethane, and propane are 26.5, 2.10, and 2.78 {micro}mol/m{sup 2}d, respectively. Continuous measurements of air and sea surface concentrations of methane were made to obtain high spatial and temporal resolution of the diffusive net sea-to-air fluxes. The atmospheric methane fluctuated between 1.70 ppm and 2.40 ppm during the entire cruise except for high concentrations (up to 4.01 ppm) sampled during the end of the occupation of GC600 and the transit between GC600 and GC185. Results from interpolations within the survey areas show the daily methane fluxes to the atmosphere at the three sites range from 0.744 to 300 mol d-1. Considering that the majority of seeps in the GOM are deep (>500 m), elevated CH{sub 4} concentrations in near-surface waters resulting from bubble-mediated CH4 transport in the water column are expected to be widespread in the Gulf of Mexico.

  8. 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.

  9. *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...

  10. 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.

  11. 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

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  13. 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

  14. 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.

  15. UNDERSTANDING METHANE EMISSIONS SOURCES AND VIABLE MITIGATION MEASURES IN THE NATURAL GAS TRANSMISSION SYSTEMS: RUSSIAN AND U.S. EXPERIENCE

    SciTech Connect

    Ishkov, A.; Akopova, Gretta; Evans, Meredydd; Yulkin, Grigory; Roshchanka, Volha; Waltzer, Suzie; Romanov, K.; Picard, David; Stepanenko, O.; Neretin, D.

    2011-10-01

    This article will compare the natural gas transmission systems in the U.S. and Russia and review experience with methane mitigation technologies in the two countries. Russia and the United States (U.S.) are the world's largest consumers and producers of natural gas, and consequently, have some of the largest natural gas infrastructure. This paper compares the natural gas transmission systems in Russia and the U.S., their methane emissions and experiences in implementing methane mitigation technologies. Given the scale of the two systems, many international oil and natural gas companies have expressed interest in better understanding the methane emission volumes and trends as well as the methane mitigation options. This paper compares the two transmission systems and documents experiences in Russia and the U.S. in implementing technologies and programs for methane mitigation. The systems are inherently different. For instance, while the U.S. natural gas transmission system is represented by many companies, which operate pipelines with various characteristics, in Russia predominately one company, Gazprom, operates the gas transmission system. However, companies in both countries found that reducing methane emissions can be feasible and profitable. Examples of technologies in use include replacing wet seals with dry seals, implementing Directed Inspection and Maintenance (DI&M) programs, performing pipeline pump-down, applying composite wrap for non-leaking pipeline defects and installing low-bleed pneumatics. The research methodology for this paper involved a review of information on methane emissions trends and mitigation measures, analytical and statistical data collection; accumulation and analysis of operational data on compressor seals and other emission sources; and analysis of technologies used in both countries to mitigate methane emissions in the transmission sector. Operators of natural gas transmission systems have many options to reduce natural gas losses

  16. 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

  17. Measuring in situ methane concentrations over time at Gas Hydrate seafloor observatories

    NASA Astrophysics Data System (ADS)

    Lapham, L.; Wilson, R. M.; Chanton, J.; Higley, P.; Lutken, C.; Riedel, M.

    2011-12-01

    Since 2006, we have been working on outfitting Gas Hydrate seafloor observatories with instruments, called Pore-Fluid Arrays, to collect and measure in situ methane concentrations and other biogeochemical parameters over time. The central technology within the PFA's uses OsmoSampler instruments that use osmosis to pull fluids slowly through ports into 300 meter-long copper tubing coil. OsmoSamplers are robust, require no power, and give sample resolution on the order of days to weeks. They allow questions about the dynamics of a system, in our case, gas hydrate systems, to be asked. For example, at the Gulf of Mexico Gas Hydrate Research Consortium monitoring station, we asked "on what time scale do gas hydrates form or decompose?" A 4-month time-series from Mississippi Canyon 118 gave unexpected results showing methane dynamics from the deep-sea influenced by regional tectonic activity. In 2009, we extended this tectonic link to methane release by asking the specific question "is shallow gas released from the seafloor when regional tectonics is active, and, if so, what is the temporal variability of such release events?" To answer this, we deployed a PFA in an area of seafloor where extensive methane venting is known to occur, Northern Cascadia margin gas hydrate sites. This area has seafloor cracks with active bubble streams and thin bacterial mats suggesting shallow gas and possible pore-fluid saturation. One of these gas crack sites, informally named "bubbly gulch", was chosen to deploy a PFA for 9 months. The PFA was modified to be ROV-deployable and was made up of 4 OsmoSamplers that were each plumbed to a port along a 1-meter probe tip using small diameter tubing. Because of the high methane concentrations anticipated, in situ pressures were maintained within the coil by the addition of a high pressure valve. Water samples were collected from the overlying water, at the sediment-water interface, and 6 and 10 cm into the sediments. Bottom water temperatures

  18. Measurement of a doubly substituted methane isotopologue, ¹³CH₃D, by tunable infrared laser direct absorption spectroscopy.

    PubMed

    Ono, Shuhei; Wang, David T; Gruen, Danielle S; Sherwood Lollar, Barbara; Zahniser, Mark S; McManus, Barry J; Nelson, David D

    2014-07-01

    Methane is an important energy resource and significant long-lived greenhouse gas. Carbon and hydrogen isotope ratios have been used to better constrain the sources of methane but interpretations based on these two parameters alone can often be inconclusive. The precise measurement of a doubly substituted methane isotopologue, (13)CH3D, is expected to add a critical new dimension to source signatures by providing the apparent temperature at which methane was formed or thermally equilibrated. We have developed a new method to precisely determine the relative abundance of (13)CH3D by using tunable infrared laser direct absorption spectroscopy (TILDAS). The TILDAS instrument houses two continuous wave quantum cascade lasers; one tuned at 8.6 μm to measure (13)CH3D, (12)CH3D, and (12)CH4, and the other at 7.5 μm to measure (13)CH4. With the use of an astigmatic Herriott cell with an effective path length of 76 m, a precision of 0.2‰ (2σ) was achieved for the measurement of (13)CH3D abundance in ca. 10 mL STP (i.e., 0.42 mmol) pure methane samples. Smaller quantity samples (ca. 0.5 mL STP) can be measured at lower precision. The accuracy of the Δ(13)CH3D measurement is 0.7‰ (2σ), evaluated by thermally equilibrating methane with a range of δD values. The precision of ±0.2‰ corresponds to uncertainties of ±7 °C at 25 °C and ±20 °C at 200 °C for estimates of apparent equilibrium temperatures. The TILDAS instrument offers a simple and precise method to determine (13)CH3D in natural methane samples to distinguish geological and biological sources of methane in the atmosphere, hydrosphere, and lithosphere.

  19. 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).

  20. 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.

  1. 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.

  2. Assessment of methane emissions from oil and gas production pads using mobile measurements.

    PubMed

    Brantley, Halley L; Thoma, Eben D; Squier, William C; Guven, Birnur B; Lyon, David

    2014-12-16

    A new mobile methane emissions inspection approach, Other Test Method (OTM) 33A, was used to quantify short-term emission rates from 210 oil and gas production pads during eight two-week field studies in Texas, Colorado, and Wyoming from 2010 to 2013. Emission rates were log-normally distributed with geometric means and 95% confidence intervals (CIs) of 0.33 (0.23, 0.48), 0.14 (0.11, 0.19), and 0.59 (0.47, 0.74) g/s in the Barnett, Denver-Julesburg, and Pinedale basins, respectively. This study focused on sites with emission rates above 0.01 g/s and included short-term (i.e., condensate tank flashing) and maintenance-related emissions. The results fell within the upper ranges of the distributions observed in recent onsite direct measurement studies. Considering data across all basins, a multivariate linear regression was used to assess the relationship of methane emissions to well age, gas production, and hydrocarbon liquids (oil or condensate) production. Methane emissions were positively correlated with gas production, but only approximately 10% of the variation in emission rates was explained by variation in production levels. The weak correlation between emission and production rates may indicate that maintenance-related stochastic variables and design of production and control equipment are factors determining emissions.

  3. 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).

  4. 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

  5. Comparison of first-order-decay modeled and actual field measured municipal solid waste landfill methane data.

    PubMed

    Amini, Hamid R; Reinhart, Debra R; Niskanen, Antti

    2013-12-01

    The first-order decay (FOD) model is widely used to estimate landfill gas generation for emissions inventories, life cycle assessments, and regulation. The FOD model has inherent uncertainty due to underlying uncertainty in model parameters and a lack of opportunities to validate it with complete field-scale landfill data sets. The objectives of this paper were to estimate methane generation, fugitive methane emissions, and aggregated collection efficiency for landfills through a mass balance approach using the FOD model for gas generation coupled with literature values for cover-specific collection efficiency and methane oxidation. This study is unique and valuable because actual field data were used in comparison with modeled data. The magnitude and variation of emissions were estimated for three landfills using site-specific model parameters and gas collection data, and compared to vertical radial plume mapping emissions measurements. For the three landfills, the modeling approach slightly under-predicted measured emissions and over-estimated aggregated collection efficiency, but the two approaches yielded statistically equivalent uncertainties expressed as coefficients of variation. Sources of uncertainty include challenges in large-scale field measurement of emissions and spatial and temporal fluctuations in methane flow balance components (generated, collected, oxidized, and emitted methane). Additional publication of sets of field-scale measurement data and methane flow balance components will reduce the uncertainty in future estimates of fugitive emissions.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. The measurement of carbon monoxide and methane in the National Capital Air Quality Control Region. I - Measurement systems

    NASA Technical Reports Server (NTRS)

    Lebel, P. J.; Lamontagne, R. A.; Goldstein, H. W.

    1976-01-01

    The Carbon Monoxide Pollution Experiment (COPE) and the National Capital Air Quality Control Region (NCAQCR) undertook a series of measurements of atmospheric CO and CH4 to determine the accuracy of the airborne COPE Correlation Interfer4meter. The device, a modified Michelson interferometer, measures the atmospheric column density of CO and CH4 at 2.3 microns with tropospheric measurement sensitivities of 70 and 10 PPB, respectively. Data for evaluating the remote measurements included atmospheric column density measurements at a ground truth site using a van-mounted infrared Fourier spectrometer; continuous ground level gas chromatographic measurements; and chromatographic data from atmospheric grab samples collected by aircraft and at ground locations. The instruments and sampling techniques used in the experiment are described in detail.

  14. Challenges and Solutions for Frequency and Energy References for Spaceborne and Airborne Integrated Path Differential Absorption Lidars

    NASA Astrophysics Data System (ADS)

    Fix, Andreas; Quatrevalet, Mathieu; Witschas, Benjamin; Wirth, Martin; Büdenbender, Christian; Amediek, Axel; Ehret, Gerhard

    2016-06-01

    The stringent requirements for both the frequency stability and power reference represent a challenging task for Integrated Path Differential Absorption Lidars (IPDA) to measure greenhouse gas columns from satellite or aircraft. Currently, the German-French methane mission MERLIN (Methan Remote Lidar Mission) is prepared. At the same time CHARM-F, an aircraft installed system has been developed at DLR as an airborne demonstrator for a spaceborne greenhouse gas mission. The concepts and realization of these important sub-systems are discussed.

  15. 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.

  16. 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

  17. 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

  18. 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.

  19. 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.

  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, 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.

  1. 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.

  2. A unified equation for calculating methane vapor pressures in the CH4-H2O system with measured Raman shifts

    USGS Publications Warehouse

    Lu, W.; Chou, I.-Ming; Burruss, R.C.; Song, Y.

    2007-01-01

    A unified equation has been derived by using all available data for calculating methane vapor pressures with measured Raman shifts of C-H symmetric stretching band (??1) in the vapor phase of sample fluids near room temperature. This equation eliminates discrepancies among the existing data sets and can be applied at any Raman laboratory. Raman shifts of C-H symmetric stretching band of methane in the vapor phase of CH4-H2O mixtures prepared in a high-pressure optical cell were also measured at temperatures between room temperature and 200 ??C, and pressures up to 37 MPa. The results show that the CH4 ??1 band position shifts to higher wavenumber as temperature increases. We also demonstrated that this Raman band shift is a simple function of methane vapor density, and, therefore, when combined with equation of state of methane, methane vapor pressures in the sample fluids at elevated temperatures can be calculated from measured Raman peak positions. This method can be applied to determine the pressure of CH4-bearing systems, such as methane-rich fluid inclusions from sedimentary basins or experimental fluids in hydrothermal diamond-anvil cell or other types of optical cell. ?? 2007 Elsevier Ltd. All rights reserved.

  3. 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.

  4. High-resolution methane emission estimates using surface measurements and the InTEM inversion system.

    NASA Astrophysics Data System (ADS)

    Connors, Sarah; Manning, Alistair; Robinson, Andrew; Riddick, Stuart; Forster, Grant; Oram, Dave; O'Doherty, Simon; Harris, Neil

    2015-04-01

    High quality GHG emission estimates will be required to successfully tackle climate change. There is a growing need for comparisons between emission estimates produced using bottom-up and top-down techniques at high spatial resolution. Here, a top-down inversion approach combining multi-year atmospheric measurements and an inversion model, InTEM, was used to estimate methane emissions for a region in the South East of the UK (~100 x 150 km). We present results covering a 2-year period (July 2012 - July 2014) in which atmospheric methane concentrations were recorded at 1 - 2 minute time-steps at four locations within the region of interest. Precise measurements were obtained using gas chromatography with flame ionisation detection (GC-FID) for all sites except one, which used a PICARRO Cavity Ring-Down Spectrometer (CRDS). These observations, along with the UK Met Office's Lagrangian particle dispersion model, NAME, were used within InTEM to produce the methane emission fields. We present results from both Bayesian and non-prior based inversion analysis at varying spatial resolutions, for annual, seasonal and monthly time frames. These results are compared with the UK National Atmospheric Emissions Inventory (NAEI) which is compiled using bottom-up methods and available at 1x1 km resolution. A thorough assessment of uncertainty is incorporated into this technique which is represented in the results. This project is part of the UK GAUGE campaign which aims to produce robust estimates of the UK GHG budget using new and existing measurement networks (e.g. the UK DECC GHG network) and modelling activities at a range of scales.

  5. Traceable measurement and uncertainty analysis of the gross calorific value of methane determined by isoperibolic calorimetry

    NASA Astrophysics Data System (ADS)

    Haloua, F.; Foulon, E.; Allard, A.; Hay, B.; Filtz, J. R.

    2015-12-01

    As methane is the major component of natural gas and non-conventional gases as biogas or mine gases, its energy content has to be measured accurately regardless of its production site for fiscal trading of transported and distributed natural gas. The determination of calorific value of fuel gases with the lowest uncertainty can only be performed by direct method with a reference gas calorimeter. To address this point, LNE developed a few years ago an isoperibolic reference gas calorimeter according to the Rossini’s principle. The energy content Hs of methane of purity 99.9995% has been measured to 55 507.996 kJ kg-1 (890.485 kJ mol-1) with an expanded relative uncertainty of 0.091% (coverage factor k  =  2.101 providing a level of confidence of approximately 95%). These results are based on ten repeated measurements and on the uncertainty assessment performed in accordance with the guide to the expression of uncertainty in measurement (GUM). The experimental setup and the results are reported here and for the first time, the fully detailed uncertainty calculation is exposed.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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).

  19. Further evaluation of wetland emission estimates from the JULES land surface model using SCIAMACHY and GOSAT atmospheric column methane measurements

    NASA Astrophysics Data System (ADS)

    Hayman, Garry; Comyn-Platt, Edward; McNorton, Joey; Chipperfield, Martyn; Gedney, Nicola

    2016-04-01

    The atmospheric concentration of methane began rising again in 2007 after a period of near-zero growth [1,2], with the largest increases observed over polar northern latitudes and the Southern Hemisphere in 2007 and in the tropics since then. The observed inter-annual variability in atmospheric methane concentrations and the associated changes in growth rates have variously been attributed to changes in different methane sources and sinks [2,3]. Wetlands are generally accepted as being the largest, but least well quantified, single natural source of CH4, with global emission estimates ranging from 142-284 Tg yr-1 [3]. The modelling of wetlands and their associated emissions of CH4 has become the subject of much current interest [4]. We have previously used the HadGEM2 chemistry-climate model to evaluate the wetland emission estimates derived using the UK community land surface model (JULES, the Joint UK Land Earth Simulator) against atmospheric observations of methane, including SCIAMACHY total methane columns [5] up to 2007. We have undertaken a series of new HadGEM2 runs using new JULES emission estimates extended in time to the end of 2012, thereby allowing comparison with both SCIAMACHY and GOSAT atmospheric column methane measurements. We will describe the results of these runs and the implications for methane wetland emissions. References [1] Rigby, M., et al.: Renewed growth of atmospheric methane. Geophys. Res. Lett., 35, L22805, 2008; [2] Nisbet, E.G., et al.: Methane on the Rise-Again, Science 343, 493, 2014; [3] Kirschke, S., et al.,: Three decades of global methane sources and sinks, Nature Geosciences, 6, 813-823, 2013; [4] Melton, J. R., et al.: Present state of global wetland extent and wetland methane modelling: conclusions from a model inter-comparison project (WETCHIMP), Biogeosciences, 10, 753-788, 2013; [5] Hayman, G.D., et al.: Comparison of the HadGEM2 climate-chemistry model against in situ and SCIAMACHY atmospheric methane data, Atmos. Chem

  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. Measuring Humidity in Methane and Natural Gas with a Microwave Technique

    NASA Astrophysics Data System (ADS)

    Gavioso, R. M.; Madonna Ripa, D.; Benyon, R.; Gallegos, J. G.; Perez-Sanz, F.; Corbellini, S.; Avila, S.; Benito, A. M.

    2014-04-01

    The results of microwave measurements with a quasi-spherical resonator in humid methane samples realized under laboratory conditions at the Istituto Nazionale di Ricerca Metrologica (INRiM) and under industrial conditions in a natural gas sample made available at the facilities of the Technical Manager of the Spanish Gas System and main supplier of natural gas in Spain (ENAGAS) are reported. Measurements at INRiM included vapor phase and condensation tests on methane samples prepared with amount fractions of water between 600 ppm and 5000 ppm at temperatures between 273 K and 295 K and pressures between 150 kPa and 1 MPa. ENAGAS measurements were performed at ambient temperature, 750 kPa on natural gas sampled from the pipeline and successively humidified at amount fractions of water between 140 ppm and 250 ppm for completeness of the comparison with several humidity sensors and instrumentation based on different technologies. To enhance the sensitivity of the microwave method at low humidity, an experimental procedure based on the relative comparison of the dielectric permittivity of the humid gas sample before and after being subject to a chemical drying process was conceived and implemented. The uncertainty budget and the final sensitivity of this procedure are discussed.

  2. Stable Isotope Measurements of Carbon Dioxide, Methane, and Hydrogen Sulfide Gas Using Frequency Modulation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Nowak-Lovato, K.

    2014-12-01

    Seepage from enhanced oil recovery, carbon storage, and natural gas sites can emit trace gases such as carbon dioxide, methane, and hydrogen sulfide. Trace gas emission at these locations demonstrate unique light stable isotope signatures that provide information to enable source identification of the material. Light stable isotope detection through surface monitoring, offers the ability to distinguish between trace gases emitted from sources such as, biological (fertilizers and wastes), mineral (coal or seams), or liquid organic systems (oil and gas reservoirs). To make light stable isotope measurements, we employ the ultra-sensitive technique, frequency modulation spectroscopy (FMS). FMS is an absorption technique with sensitivity enhancements approximately 100-1000x more than standard absorption spectroscopy with the advantage of providing stable isotope signature information. We have developed an integrated in situ (point source) system that measures carbon dioxide, methane and hydrogen sulfide with isotopic resolution and enhanced sensitivity. The in situ instrument involves the continuous collection of air and records the stable isotope ratio for the gas being detected. We have included in-line flask collection points to obtain gas samples for validation of isotopic concentrations using our in-house isotope ratio mass spectroscopy (IRMS). We present calibration curves for each species addressed above to demonstrate the sensitivity and accuracy of the system. We also show field deployment data demonstrating the capabilities of the system in making live dynamic measurements from an active source.

  3. Detecting methane plumes with the APEX imaging spectrometer

    NASA Astrophysics Data System (ADS)

    Kuhlmann, Gerrit; Hueni, Andreas; Brunner, Dominik

    2016-04-01

    The Airborne Prism EXperiment (APEX) is an imaging spectrometer primarily designed for environmental remote sensing of the land surface but also allows observing atmospheric trace gases. To test if APEX can be used to detect strong methane plumes, the instrument was flown over a coal mining area near Ibbenbürren (Germany). According to the European Point source emission inventory (E-PRTR), emissions from the ventilation shafts of these coal mines are the largest single source of methane in Germany. We present the first measurements of methane ever taken by APEX making use of the absorption features of methane in the short-wave infrared spectral range. Our detection algorithm uses a matched filter to identify the presence of methane. The filter is tested in two spectral windows (1600-1700 nm and 2100-2500 nm) and for different spatial binning of pixels to improve the signal-to-noise. Using this approach, we could clearly identify two meandering methane plumes originating from the ventilation shafts of two coal mines (Bockradener Schacht and Theodor Schacht). The filter performed best for the spectral window from 1600-1700 nm with a binning of 10×10 pixels corresponding to a spatial resolution of about 35×25 m2 In conclusions, we could demonstrate that APEX is able to detect strong methane plumes. The results provide a basis for developing more sophisticated and quantitative methane retrievals.

  4. 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.).

  5. 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%.

  6. 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.

  7. 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.

  8. 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

  9. Recent Advances in Measurement and Dietary Mitigation of Enteric Methane Emissions in Ruminants

    PubMed Central

    Patra, Amlan K.

    2016-01-01

    Methane (CH4) emission, which is mainly produced during normal fermentation of feeds by the rumen microorganisms, represents a major contributor to the greenhouse gas (GHG) emissions. Several enteric CH4 mitigation technologies have been explored recently. A number of new techniques have also been developed and existing techniques have been improved in order to evaluate CH4 mitigation technologies and prepare an inventory of GHG emissions precisely. The aim of this review is to discuss different CH4 measuring and mitigation technologies, which have been recently developed. Respiration chamber technique is still considered as a gold standard technique due to its greater precision and reproducibility in CH4 measurements. With the adoption of recent recommendations for improving the technique, the SF6 method can be used with a high level of precision similar to the chamber technique. Short-term measurement techniques of CH4 measurements generally invite considerable within- and between-animal variations. Among the short-term measuring techniques, Greenfeed and methane hood systems are likely more suitable for evaluation of CH4 mitigation studies, if measurements could be obtained at different times of the day relative to the diurnal cycle of the CH4 production. Carbon dioxide and CH4 ratio, sniffer, and other short-term breath analysis techniques are more suitable for on farm screening of large number of animals to generate the data of low CH4-producing animals for genetic selection purposes. Different indirect measuring techniques are also investigated in recent years. Several new dietary CH4 mitigation technologies have been explored, but only a few of them are practical and cost-effective. Future research should be directed toward both the medium- and long-term mitigation strategies, which could be utilized on farms to accomplish substantial reductions of CH4 emissions and to profitably reduce carbon footprint of livestock production systems. This review presents

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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 contr