WorldWideScience

Sample records for atmospheric infrared sounder

  1. Global Daily Atmospheric State Profiles from the Atmospheric Infrared Sounder

    Science.gov (United States)

    Pagano, Thomas S.; Aumann, Hartmut H.; Fetzer, Eric J.; Lambrigtsen, Bjorn H.; Chahine, Moustafa T.

    2008-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the EOS Aqua Spacecraft, launched on May 4, 2002. AIRS has 2378 infrared channels ranging from 3.7 (micro)m to 15.4 (micro)m and a 13.5 km footprint. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy on a global scale, as well as water vapor profiles, clouds, dust and trace gas amounts for CO2, CO, SO2, O3 and CH4.[1] AIRS data are used for weather forecasting and studies of global climate change. The AIRS is a 'facility' instrument developed by NASA as an experimental demonstration of advanced technology for remote sensing and the benefits of high resolution infrared spectra to science investigations.

  2. Sensitivity Analysis for Atmospheric Infrared Sounder (AIRS) CO2 Retrieval

    Science.gov (United States)

    Gat, Ilana

    2012-01-01

    The Atmospheric Infrared Sounder (AIRS) is a thermal infrared sensor able to retrieve the daily atmospheric state globally for clear as well as partially cloudy field-of-views. The AIRS spectrometer has 2378 channels sensing from 15.4 micrometers to 3.7 micrometers, of which a small subset in the 15 micrometers region has been selected, to date, for CO2 retrieval. To improve upon the current retrieval method, we extended the retrieval calculations to include a prior estimate component and developed a channel ranking system to optimize the channels and number of channels used. The channel ranking system uses a mathematical formalism to rapidly process and assess the retrieval potential of large numbers of channels. Implementing this system, we identifed a larger optimized subset of AIRS channels that can decrease retrieval errors and minimize the overall sensitivity to other iridescent contributors, such as water vapor, ozone, and atmospheric temperature. This methodology selects channels globally by accounting for the latitudinal, longitudinal, and seasonal dependencies of the subset. The new methodology increases accuracy in AIRS CO2 as well as other retrievals and enables the extension of retrieved CO2 vertical profiles to altitudes ranging from the lower troposphere to upper stratosphere. The extended retrieval method for CO2 vertical profile estimation using a maximum-likelihood estimation method. We use model data to demonstrate the beneficial impact of the extended retrieval method using the new channel ranking system on CO2 retrieval.

  3. Validation of the Radiometric Stability of the Atmospheric Infrared Sounder

    Science.gov (United States)

    Aumann, H. H.; Elliott, D.; Strow, L. L.

    2012-01-01

    It has been widely accepted that an infrared sounder in low polar orbit is capable of producing climate quality data, if the spectral brightness temperatures have instrumental trends of less than 10 mK/yr. Achieving measurement stability at this level is not only very demanding of the design of the instrument, it is also pushes the state of art of measuring on orbit what stability is actually achieved. We discuss this using Atmospheric Infrared Sounder (AIRS) L1B data collected between 2002 and 2011. We compare the L1B brightness temperature observed in cloud filtered night tropical ocean spectra (obs) to the brightness temperature calculated based on the known surface emissivity, temperature and water vapor profiles from the ECMWF ReAnalysis (ERA) and the growth rates of CO2, N2O and Ozone. The trend in (obs-calc) is a powerful tool for the evaluation of the stability of the 2378 AIRS channels. We divided the channels into seven classes: All channels which sound in the stratosphere (at pressure levels below 150 hPa), 14 micron CO2 sounding, 4 micron CO2 P-branch sounding, 4 micron CO2 R-branch sounding, water vapor sounding, shortwave surface sounding and longwave surface sounding. The peak in the weighting function at 1050 hPa separates sounding and surface channels. The boundary between shortwave and longwave is 5 microns. Except for the stratosphere sounding channels, the remaining six groups have (obs-calc) trends of less than 20 mK/yr. The longwave surface channels have trends of 2 mK/yr, significantly less than the 8 mK/yr trend seem in the shortwave window channels. Based on the design of the instrument, trends within a group of channels should be the same. While the longwave and shortwave trends are less than the canonical 10 mK/yr, the larger trend in the shortwave channels could be an artifact of using the pre-launch determined calibration coefficients. This is currently under evaluation. The trend in (obs-calc) for the non-surface sounding channels, in

  4. Validation of the radiometric stability of the Atmospheric Infrared Sounder

    Science.gov (United States)

    Aumann, H. H.; Elliott, D.; Strow, L. L.

    2012-09-01

    It has been widely accepted that an infrared sounder in low polar orbit is capable of producing climate quality data, if the spectral brightness temperatures have instrumental trends of less than 10 mK/yr. Achieving measurement stability at this level is not only very demanding of the design of the instrument, it is also pushes the state of art of measuring on orbit what stability is actually achieved. We discuss this using Atmospheric Infrared Sounder (AIRS) L1B data collected between 2002 and 2011. We compare the L1B brightness temperature observed in cloud filtered night tropical ocean spectra (obs) to the brightness temperature calculated based on the known surface emissivity, temperature and water vapor profiles from the ECMWF ReAnalysis (ERA) and the growth rates of CO2 , N2O and Ozone. The trend in (obscalc) is a powerful tool for the evaluation of the stability of the 2378 AIRS channels. We divided the channels into seven classes: All channels which sound in the stratosphere (at pressure levels below 150 hPa), 14 um CO2 sounding, 4 um CO2 P-branch sounding, 4um CO2 R-branch sounding, water vapor sounding, shortwave surface sounding and longwave surface sounding. The peak in the weighting function at 1050 hPa separates sounding and surface channels. The boundary between shortwave and longwave is 5 μm. Except for the stratosphere sounding channels, the remaining six groups have (obs-calc) trends of less than 20 mK/yr. The longwave surface channels have trends of 2 mK/yr, significantly less than the 8 mK/yr trend seem in the shortwave window channels. Based on the design of the instrument, trends within a group of channels should be the same. While the longwave and shortwave trends are less than the canonical 10 mK/yr, the larger trend in the shortwave channels could be an artifact of using the pre-launch determined calibration coefficients. This is currently under evaluation. The trend in (obs-calc) for the non-surface sounding channels, in particular for

  5. How Well Can Infrared Sounders Observe the Atmosphere and Surface Through Clouds?

    Science.gov (United States)

    Zhou, Daniel K.; Larar, Allen M.; Liu, Xu; Smith, William L.; Strow, L. Larrabee; Yang, Ping

    2010-01-01

    Infrared sounders, such as the Atmospheric Infrared Sounder (AIRS), the Infrared Atmospheric Sounding Interferometer (IASI), and the Cross-track Infrared sounder (CrIS), have a cloud-impenetrable disadvantage in observing the atmosphere and surface under opaque cloudy conditions. However, recent studies indicate that hyperspectral, infrared sounders have the ability to detect cloud effective-optical and microphysical properties and to penetrate optically thin clouds in observing the atmosphere and surface to a certain degree. We have developed a retrieval scheme dealing with atmospheric conditions with cloud presence. This scheme can be used to analyze the retrieval accuracy of atmospheric and surface parameters under clear and cloudy conditions. In this paper, we present the surface emissivity results derived from IASI global measurements under both clear and cloudy conditions. The accuracy of surface emissivity derived under cloudy conditions is statistically estimated in comparison with those derived under clear sky conditions. The retrieval error caused by the clouds is shown as a function of cloud optical depth, which helps us to understand how well infrared sounders can observe the atmosphere and surface through clouds.

  6. Demonstrating the Operational Value of Atmospheric Infrared Sounder (AIRS) Profiles in the Pre-Convective Environment

    Science.gov (United States)

    Kozlowski, Danielle; Zavodsky, Bradley; Stano, Geoffrey; Jedlovec, Gary

    2011-01-01

    The Short-term Prediction Research and Transition (SPoRT) is a project to transition those NASA observations and research capabilities to the weather forecasting community to improve the short-term regional forecasts. This poster reviews the work to demonstrate the value to these forecasts of profiles from the Atmospheric Infrared Sounder (AIRS) instrument on board the Aqua satellite with particular assistance in predicting thunderstorm forecasts by the profiles of the pre-convective environment.

  7. Development of Level 3 (gridded) products for the Atmospheric Infrared Sounder (AIRS)

    Science.gov (United States)

    Granger, Stephanie L.; Leroy, Stephen S.; Manning, Evan M.; Fetzer, Eric J.; Oliphant, Robert B.; Braverman, Amy; Lee, Sung-Yung; Lambrigtsen, Bjom H.

    2004-01-01

    The Atmospheric Infrared Sounder (AIRS) sounding system is a suite of infrared and microwave instruments flown as part of NASA's Earth Observing System (EOS) onboard the Aqua platform. The AIRS dataset provides a daily, global view of Earth processes at a finer vertical resolution than ever before. However, analysis of the AIRS data is a daunting task given the sheer volume and complexity of the data. The volume of data produced by the EOS project is unprecedented; the AIRS project alone will produce many terabytes of data over the lifetime of the mission. This paper describes development of AIRS Level 3 data products that will help to alleviate problems of access and usability.

  8. Preface to Special Section: Validation of Atmospheric Infrared Sounder Observations

    Science.gov (United States)

    Fetzer, Eric J.

    2006-01-01

    The papers described below demonstrate that the AIRS calibrated radiances and retrieved geophysical products generally meet or exceed the prelaunch specifications. The retrieved quantities show little variation in uncertainty as a function of cloud amount. However, AIRS retrieval yield is a rapidly decreasing function of cloud amount; at about 80% cloudiness essentially no infrared radiances are used in the retrieval processes. Also, AIRS performance has not been demonstrated for all conditions and products. Calibrated and forward calculated radiances meet performance specifications for conditions varying from the cold poles to warm tropics. The retrieval system performs well over extrapolar land in the free troposphere (2-15 km above the surface) and over extrapolar oceans at all tropospheric altitudes. The AIRS retrieval algorithms have not been optimized for polar winter conditions, so no such results are presented in these papers.

  9. Improved Products for Assimilation and Model Validation from the Atmospheric Infrared Sounder (AIRS) on Aqua

    Science.gov (United States)

    Pagano, Thomas S.

    2008-01-01

    The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in the 3.7-15.4 micrometer spectral region with spectral resolution of better than 1200. Key channels from the AIRS Level 1B calibrated radiance product are currently assimilated into operational weather forecasts at NCEP and other international agencies. Additional Level 2 products for assimilation include the AIRS cloud cleared radiances and the geophysical retrieved temperature and water vapor profiles. The AIRS products are also used to validate climate model vertical and horizontal biases and transport of water vapor and key trace gases including Carbon Dioxide and Ozone. The wide variety of products available from the AIRS make it well suited to study processes affecting the interaction of these products.

  10. The spaceborne infrared atmospheric sounder for geosynchronous earth orbit (SIRAS-G): pathfinder to space

    Science.gov (United States)

    Kampe, Thomas U.; Chase, Holden

    2007-09-01

    The Spaceborne Infrared Sounder for Geosynchronous Earth Orbit (SIRAS-G) was developed by Ball Aerospace and Technologies Corp (BATC) under NASA's 2002 Instrument Incubator Program. SIRAS-G is a technology development program focused on next-generation IR imaging spectrometers for sounding of the atmosphere. SIRAS-G is ideally suited for measuring atmospheric temperature and water vapor profiles, trace gases concentrations, land and ocean surface temperatures and the IR mineral dust aerosol signature from satellite, providing high-spectral resolution imaging spectroscopy over a broad IR spectral range and extended field of view. Instrument concepts for future mission in LEO and GEO are discussed, including an instrument concept to be flown in low earth orbit having the potential to provide high spatial resolution, comparable to that of MODIS, along with the high spectral resolution currently being demonstrated by the Atmospheric Infrared Sounder (AIRS). This capability would dramatically improve the yield of cloud-free pixels scenes that can be assimilated into Numerical Weather Prediction (NWP) models. The SIRAS-G dispersive spectrometer module is readily adaptable for missions in LEO, GEO and MEO orbits and can be optimized for spectral resolution over subsets of the total spectral range. We have completed the 3-year SIRAS-G IIP development effort, including successful testing of the SIRAS-G laboratory demonstration spectrometer that utilized the Hawaii 1RG MWIR FPA. Performance testing was conducted at cryogenic temperatures and the performance of the demo instrument has been quantified including measurement of keystone distortion, spectral smile, MTF, and the spectral response function (SRF) to high accuracy. We present the results of the laboratory instrument development including characterization of the demonstration instrument performance. We discuss instrument concepts utilizing SIRAS-G technology for potential future missions including an anticipated

  11. Validation of the Atmospheric Infrared Sounder (AIRS) over the Antarctic Plateau: Low Radiance, Low Humidity, and Thin Clouds

    Science.gov (United States)

    Tobin, David C.

    2005-01-01

    The main goal of the project has been to use specialized measurements collected at the Antarctic Plateau to provide validation of the Atmospheric InfraRed Sounder (AIRS) spectral radiances and some AIRS Level 2 products. As proposed, efforts conducted at the University of Wisconsin are focused on providing technical information, data, and software in support of the validation studies.

  12. Three Years of Atmospheric Infrared Sounder Radiometric Calibration Validation using Sea Surface Temperatures

    Science.gov (United States)

    Aumann, H. H.; Broberg, Steve; Elliott, Denis; Gaiser, Steve; Gregorich, Dave

    2006-01-01

    This paper evaluates the absolute accuracy and stability of the radiometric calibration of the Atmospheric Infrared Sounder (AIRS) by analyzing the difference between the brightness temperatures measured at 2616 cm(exp -1) and those calculated at the top of the atmosphere (TOA), using the Real-Time Global Sea Surface Temperature (RTGSST) for cloud-free night tropical oceans between +/- 30 degrees latitude. The TOA correction is based on radiative transfer. The analysis of the first 3 years of AIRS radiances verifies the absolute calibration at 2616 cm(exp -1) to better than 200 mK, with better than 16 mK/yr stability. The AIRS radiometric calibration uses an internal full aperture wedge blackbody with the National Institute of Standards and Technology (NIST) traceable prelaunch calibration coefficients. The calibration coefficients have been unchanged since launch. The analysis uses very tight cloud filtering, which selects about 7000 cloud-free tropical ocean spectra per day, about 0.5% of the data. The absolute accuracy and stability of the radiometry demonstrated at 2616 cm(sup -1) are direct consequences of the implementation of AIRS as a thermally controlled, cooled grating-array spectrometer and meticulous attention to details. Comparable radiometric performance is inferred from the AIRS design for all 2378 channels. AIRS performance sets the benchmark for what can be achieved with a state-of-the-art hyperspectral radiometer from polar orbit and what is expected from future hyperspectral sounders. AIRS was launched into a 705 km altitude polar orbit on NASA's Earth Observation System (EOS) Aqua spacecraft on 4 May 2002. AIRS covers the 3.7-15.4 micron region of the thermal infrared spectrum with a spectral resolution of nu/Delta nu = 1200 and has returned 3.7 million spectra of the upwelling radiance each day since the start of routine data gathering in September 2002.

  13. Performance status of the Atmospheric Infrared Sounder ten years after launch

    Science.gov (United States)

    Pagano, Thomas S.; Broberg, Steve; Aumann, Hartmut H.; Elliott, Denis; Manning, Evan; Strow, Larrabee

    2012-11-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the EOS Aqua Spacecraft, launched on May 4, 2002. AIRS has 2378 infrared channels ranging from 3.7 μm to 15.4 μm and a 13.5 km footprint at nadir. The AIRS is a "facility" instrument developed by NASA as an experimental demonstration of advanced technology for remote sensing and the benefits of high resolution infrared spectra to science investigations. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy on a global scale, as well as water vapor profiles and trace gas amounts for CO2, CO, SO2, O3 and CH4. AIRS data are used for weather forecasting, climate process studies and validating climate models. The AIRS instrument has far exceeded its required design life of 5 years, with over 10 years of operations as of September 2012. While the instrument has performed exceptionally well, with little signs of wear, the AIRS Project continues to monitor and maintain the health of AIRS, characterize its behavior and improve performance where possible. Radiometric stability has been monitored and trending shows better than 16 mK/year stability. Spectral calibration stability is better than 1 ppm/year, and a new gain table was recently uploaded to recover 100 significantly degraded or dead channels by switching to their redundant counterpart. At this time we expect the AIRS to continue to perform well for the next decade.

  14. Hurricane Frances as Observed by NASA's Spaceborne Atmospheric Infrared Sounder (AIRS) - Total Water

    Science.gov (United States)

    2004-01-01

    Born in the Atlantic, Hurricane Frances became a category 4 hurricane on August 31, 2004. Expectations are the hurricane will hit the Space Coast of Florida in Brevard County early Sunday morning. This movie is a time-series of maps that show AIRS observations of the total amount of water vapor present in the atmospheric column above each point of the Earth's surface. If all the water vapor in the column were forced to fall as rain, the depth of the resulting puddle on the surface at that point is equal to the value shown on the map. Fifty millimeters (mm) is about 2 inches. The large band of maximum water vapor in the neighborhood of the equator is the Intertropical Convergence Zone (ITCZ), a region of strong convection and powerful thunderstorms. This movie shows the total precipitable water vapor from August 23 through September 2, 2004. You can see Hurricane Frances as it moves through the Caribbean toward Florida, and the changes in intensity are visible. The eye has been marked with a red spot. The water vapor encompassed by the hurricane is also the result of the very strong convection which is an integral part of the formation and intensification of tropical storms. If you look at the last frame of the movie in the lower right corner, you can see the emergence of a new tropical storm. Ivan makes its debut in the Atlantic. The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA

  15. Local, regional, and global views of tropospheric carbon monoxide from the Atmospheric Infrared Sounder (AIRS)

    Science.gov (United States)

    McMillan, W. Wallace; Yurganov, Leonid

    2008-04-01

    More than five years of CO retrievals from the Atmospheric InfraRed Sounder (AIRS) onboard NASA's Aqua satellite reveal variations in tropospheric CO on timescales from twelve hours to five years and on spatial scales from local to global. The shorter timescales are invaluable to monitor daily variations in CO emissions, to enable three-dimensional tracking of atmospheric motions, and to enhance insights into atmospheric mixing. Previous studies have utilized AIRS CO retrievals over the course of days to weeks to track plumes from large forest fires. On the local scale, we will present AIRS observations of pollution from several northern hemisphere Megacities. On the regional scale, we will present AIRS observations of the Mexico City pollution plume. We will illustrate global scale AIRS CO observations of interannual variations linked to the influence of large-scale atmospheric perturbations from the El Nino Southern Oscillation (ENSO). In particular, we observe a quasi-biennial variation in CO emissions from Indonesia with varying magnitudes in peak emission occurring in 2002, 2004, and 2006. Examining satellite rainfall measurements over Indonesia, we find the enhanced CO emission correlates with occasions of less rainfall during the month of October. Continuing this satellite record of tropospheric CO with measurements from the European IASI instrument will permit construction of a long time-series useful for further investigations of climatological variations in CO emissions and their impact on the health of the atmosphere.

  16. Seven Years’ Observation of Mid-Upper Tropospheric Methane from Atmospheric Infrared Sounder

    Directory of Open Access Journals (Sweden)

    Thomas S. Pagano

    2010-11-01

    Full Text Available The Atmospheric Infrared Sounder (AIRS on EOS/Aqua platform provides a measurement of global methane (CH4 in the mid-upper troposphere since September, 2002. As a thermal infrared sounder, the most sensitivity of AIRS to atmospheric CH4 is in the mid-upper troposphere with the degree of freedom of ~1.0. Validation of AIRS CH4 product versus thousands of aircraft profiles (convolved using the AIRS averaging kernels demonstrates that its RMS error (RMSE is mostly less than 1.5%, and its quality is pretty stable from 2003 to 2009. For scientific analysis of the spatial and temporal variation of mid-upper tropospheric CH4 (MUT-CH4 in the High Northern Hemisphere (HNH, it is more valuable to use the AIRS retrieved CH4 in a layer of about 100 hPa below tropopause (“Representative Layer” than in a fixed pressure layer. Further analysis of deseasonalized time-series of AIRS CH4 in both a fixed pressure layer and the “Representative Layer” of AIRS (only for the HNH from 2003 to 2009 indicates that, similar to the CH4 in the marine boundary layer (MBL that was found to increase in 2007–2008, MUT-CH4 was also observed to have a recent increase but the most significant increase occurred in 2008. MUT-CH4 continued to increase in 2009, especially in the HNH. Moreover, the trend of MUT-CH4 from 2006 to 2008 is lower than the trend of CH4 in the MBL by 30–40% in both the southern hemisphere and HNH. This delay for the MUT-CH4 increase of about one year than CH4 in the MBL as well as the smaller increase trend for MUT-CH4 suggest that surface emission is likely a major driver for the recent CH4 increase. It is also found that the seasonal cycle of MUT-CH4 is different from CH4 in the MBL due to the impact of transport, in addition to the surface emission and the photochemical loss.

  17. Seven Years of Observations of Mid-Tropospheric CO2 from the Atmospheric Infrared Sounder

    Science.gov (United States)

    Pagano, Thomas S.; Chahine, Moustafa T.; Olsen, Edward T.

    2010-01-01

    The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in the 3.7-15.4 um spectral region with spectral resolution of better than 1200. The AIRS was designed to measure temperature and water vapor profiles and cloud properties for improvement in weather forecast and improved parameterization of climate processes. Currently the AIRS Level 1B Radiance Products are assimilated by NWP centers and have shown considerable forecast improvement. Scientists have also demonstrated accurate retrievals of minor gases from AIRS including Carbon Monoxide, Methane, and Ozone. The excellent sensitivity and stability of the AIRS instrument has recently allowed the AIRS team to successfully retrieve Carbon Dioxide (CO2) concentrations in the mid-troposphere (8-10 km) with a horizontal resolution of 100 km and accuracy of 1-2 ppm. The AIRS retrieves over 15,000 measurements per day and can achieve full global coverage in 30 days. The AIRS CO2 accuracy has been validated against a variety of aircraft measurements in the mid-troposphere and upward looking interferometers. Findings from the AIRS data include higher than expected variability in the mid-troposphere, the presence of a belt of CO2 in the southern hemisphere, and numerous observations of atmospheric circulation including the effects of El Nino/La Nina on the CO2 concentrations in the mid-troposphere. The full mid-tropospheric AIRS CO2 data set is now available at the NASA GES/DISC for almost eight years since AIRS has been operational.

  18. Simultaneous physical retrieval of surface emissivity spectrum and atmospheric parameters from infrared atmospheric sounder interferometer spectral radiances.

    Science.gov (United States)

    Masiello, Guido; Serio, Carmine

    2013-04-10

    The problem of simultaneous physical retrieval of surface emissivity, skin temperature, and temperature, water-vapor, and ozone atmospheric profiles from high-spectral-resolution observations in the infrared is formulated according to an inverse problem with multiple regularization parameters. A methodology has been set up, which seeks an effective solution to the inverse problem in a generalized L-curve criterion framework. The a priori information for the surface emissivity is obtained on the basis of laboratory data alone, and that for the atmospheric parameters by climatology or weather forecasts. To ensure that we deal with a problem of fewer unknowns than observations, the dimensionality of the emissivity is reduced through expansion in Fourier series. The main objective of this study is to demonstrate the simultaneous retrieval of emissivity, skin temperature, and atmospheric parameters with a two-dimensional L-curve criterion. The procedure has been demonstrated with spectra observed from the infrared atmospheric sounder interferometer, flying onboard the European Meteorological Operational satellite. To check the quality and reliability of the methodology, we have used spectra recorded over regions characterized by known or stable emissivity. These include sea surface, for which effective emissivity models are known, and arid lands (Sahara and Namib Deserts) that are known to exhibit the characteristic spectral signature of quartz-rich sand. PMID:23670773

  19. Impact of Atmospheric Infrared Sounder (AIRS) Thermodynamic Profiles on Regional Weather Forecasting

    Science.gov (United States)

    Chou, Shih-Hung; Zavodsky, Bradley T.; Jedlovee, Gary J.

    2010-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles with accuracy comparable to that of radiosondes. The purpose of this paper is to describe a procedure to assimilate AIRS thermodynamic profile data into a regional configuration of the Advanced Research Weather Research and Forecasting (WRF-ARW) model using its three-dimension variational (3DVAR) analysis component (WRF-Var). Quality indicators are used to select only the highest quality temperature and moisture profiles for assimilation in both clear and partly cloudy regions. Separate error characteristics for land and water profiles are also used in the assimilation process. Assimilation results indicate that AIRS profiles produce an analysis closer to in situ observations than the background field. Forecasts from a 37-day case study period in the winter of 2007 show that AIRS profile data can lead to improvements in 6-h cumulative precipitation forecasts due to instability added in the forecast soundings by the AIRS profiles. Additionally, in a convective heavy rainfall event from February 2007, assimilation of AIRS profiles produces a more unstable boundary layer resulting in enhanced updrafts in the model. These updrafts produce a squall line and precipitation totals that more closely reflect ground-based observations than a no AIRS control forecast. The location of available high-quality AIRS profiles ahead of approaching storm systems is found to be of paramount importance to the amount of impact the observations will have on the resulting forecasts.

  20. Impact of Atmospheric Infrared Sounder (AIRS) Thermodynamic Profiles on Regional Precipitation Forecasting

    Science.gov (United States)

    Chou, S.-H.; Zavodsky, B. T.; Jedloved, G. J.

    2010-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles in clear and cloudy regions with accuracy which approaches that of radiosondes. The purpose of this paper is to describe an approach to assimilate AIRS thermodynamic profile data into a regional configuration of the Advanced Research WRF (ARW) model using WRF-Var. Quality indicators are used to select only the highest quality temperature and moisture profiles for assimilation in clear and partly cloudy regions, and uncontaminated portions of retrievals above clouds in overcast regions. Separate error characteristics for land and water profiles are also used in the assimilation process. Assimilation results indicate that AIRS profiles produce an analysis closer to in situ observations than the background field. Forecasts from a 37-day case study period in the winter of 2007 show that AIRS profile data can lead to improvements in 6-h cumulative precipitation forecasts resulting from improved thermodynamic fields. Additionally, in a convective heavy rainfall event from February 2007, assimilation of AIRS profiles produces a more unstable boundary layer resulting in enhanced updrafts in the model. These updrafts produce a squall line and precipitation totals that more closely reflect ground-based observations than a no AIRS control forecast. The location of available high-quality AIRS profiles ahead of approaching storm systems is found to be of paramount importance to the amount of impact the observations will have on the resulting forecasts.

  1. Evaluating the Impact of Atmospheric Infrared Sounder (AIRS) Data On Convective Forecasts

    Science.gov (United States)

    Kozlowski, Danielle; Zavodsky, Bradley

    2011-01-01

    The Short-term Prediction Research and Transition Center (SPoRT) is a collaborative partnership between NASA and operational forecasting partners, including a number of National Weather Service (NWS) offices. SPoRT provides real-time NASA products and capabilities to its partners to address specific operational forecast challenges. The mission of SPoRT is to transition observations and research capabilities into operations to help improve short-term weather forecasts on a regional scale. Two areas of focus are data assimilation and modeling, which can to help accomplish SPoRT's programmatic goals of transitioning NASA data to operational users. Forecasting convective weather is one challenge that faces operational forecasters. Current numerical weather prediction (NWP) models that operational forecasters use struggle to properly forecast location, timing, intensity and/or mode of convection. Given the proper atmospheric conditions, convection can lead to severe weather. SPoRT's partners in the National Oceanic and Atmospheric Administration (NOAA) have a mission to protect the life and property of American citizens. This mission has been tested as recently as this 2011 severe weather season, which has seen more than 300 fatalities and injuries and total damages exceeding $10 billion. In fact, during the three day period from 25-27 April, 1,265 storms reports (362 tornado reports) were collected making this three day period one of most active in American history. To address the forecast challenge of convective weather, SPoRT produces a real-time NWP model called the SPoRT Weather Research and Forecasting (SPoRT-WRF), which incorporates unique NASA data sets. One of the NASA assets used in this unique model configuration is retrieved profiles from the Atmospheric Infrared Sounder (AIRS).The goal of this project is to determine the impact that these AIRS profiles have on the SPoRT-WRF forecasts by comparing to a current operational model and a control SPoRT-WRF model

  2. Characterization and validation of methane products from the Atmospheric Infrared Sounder (AIRS)

    Science.gov (United States)

    Xiong, Xiaozhen; Barnet, Chris; Maddy, Eric; Sweeney, Colm; Liu, Xingpin; Zhou, Lihang; Goldberg, Mitch

    2008-09-01

    This paper presents the characterization and validation of retrievals of atmospheric methane (CH4) vertical profiles by the Atmospheric Infrared Sounder (AIRS) on the EOS/Aqua platform. AIRS channels near 7.6 μm are used for CH4 retrieval, and they are most sensitive to the middle to upper troposphere, i.e., about 200-300 hPa in the tropics and 400-500 hPa in the polar region. The atmospheric temperature-humidity profiles, surface skin temperature, and emissivity required to derive CH4 are obtained from retrievals using separate AIRS channels and the Advanced Microwave Sounding Unit (AMSU). Comparison of AIRS retrieved profiles with some in situ aircraft CH4 profiles implied that the forward model used in the AIRS retrieval system V4.0 required a 2% increase in methane absorption coefficients for strong absorption channels, and this bias adjustment was implemented in the AIRS retrieval system V5.0. As a new operational product in V5.0, AIRS CH4 were validated using in situ aircraft observations at 22 sites of the NOAA Earth System Research Laboratory, Global Monitoring Division (NOAA/ESRL/GMD), ranging from the Arctic to the tropical South Pacific Ocean, but their altitudes are usually above 300 hPa. The results show the bias of the retrieved CH4 profiles for this version is -1.4˜0.1% and its RMS difference is about 0.5-1.6%, depending on altitude. These validation comparisons provide critical assessment of the retrieval algorithm and will continue using more in situ observations together with future improvement to the retrieval algorithm. AIRS CH4 products include not only the CH4 profile but also the information content. As examples, the products of AIRS CH4 in August 2004 and the difference of CH4 in May and September 2004 are shown. From these results a few features are evident: (1) a large AIRS CH4 plume southwest of the Tibetan plateau that may be associated with deep convection during the Asian summer monsoon; (2) high mixing ratios of AIRS CH4 in

  3. Evaluation of the Impact of Atmospheric Infrared Sounder (AIRS) Radiance and Profile Data Assimilation in Partly Cloudy Regions

    Science.gov (United States)

    Zavodsky, Bradley; Srikishen, Jayanthi; Jedlovec, Gary

    2013-01-01

    Improvements to global and regional numerical weather prediction have been demonstrated through assimilation of data from NASA s Atmospheric Infrared Sounder (AIRS). Current operational data assimilation systems use AIRS radiances, but impact on regional forecasts has been much smaller than for global forecasts. Retrieved profiles from AIRS contain much of the information that is contained in the radiances and may be able to reveal reasons for this reduced impact. Assimilating AIRS retrieved profiles in an identical analysis configuration to the radiances, tracking the quantity and quality of the assimilated data in each technique, and examining analysis increments and forecast impact from each data type can yield clues as to the reasons for the reduced impact. By doing this with regional scale models individual synoptic features (and the impact of AIRS on these features) can be more easily tracked. This project examines the assimilation of hyperspectral sounder data used in operational numerical weather prediction by comparing operational techniques used for AIRS radiances and research techniques used for AIRS retrieved profiles. Parallel versions of a configuration of the Weather Research and Forecasting (WRF) model with Gridpoint Statistical Interpolation (GSI) are run to examine the impact AIRS radiances and retrieved profiles. Statistical evaluation of 6 weeks of forecast runs will be compared along with preliminary results of in-depth investigations for select case comparing the analysis increments in partly cloudy regions and short-term forecast impacts.

  4. Information-based mid-upper tropospheric methane derived from Atmospheric Infrared Sounder (AIRS) and its validation

    Science.gov (United States)

    Xiong, X.; Barnet, C.; Wei, J.; Maddy, E.

    2009-07-01

    Atmospheric Infrared Sounder (AIRS) measurements of methane (CH4) generally contain about 1.0 degree of freedom and are therefore dependent on a priori assumptions about the vertical methane distribution as well as the temperature lapse rate and the amount of moisture. Thus it requires that interpretation and/or analysis of the CH4 spatial and temporal variation based on the AIRS retrievals need to use the averaging kernels (AK). To simplify the use of satellite retrieved products for scientific analysis, a method based on the information content of the retrievals is developed, in which the AIRS retrieved CH4 in the layer from 50 to 250 hPa below the tropopause is used to characterize the mid-upper tropospheric CH4 in the mid-high latitude regions. The basis of this method is that in the mid-high latitude regions the maximum sensitive layers of AIRS to CH4 have a good correlation with the tropopause heights, and these layers are usually between 50 and 250 hPa below the tropopause. Validation using the aircraft measurements from NOAA/ESRL/GMD and the campaigns INTEX-A and -B indicated that the correlation of AIRS mid-upper tropospheric CH4 with aircraft measurements is ~0.6-0.7, and its the bias and rms difference are less than ±1% and 1.2%, respectively. Further comparison of the CH4 seasonal cycle indicated that the cycle from AIRS mid-upper tropospheric CH4 is in a reasonable agreement with NOAA aircraft measurements. This method provides a simple way to use the thermal infrared sounders data to approximately analyze the spatial and temporal variation CH4 in the upper free tropospere without referring the AK. This method is applicable to derive tropospheric CH4 as well as other trace gases for any thermal infrared sensors.

  5. Global and Regional Seasonal Variability of Mid-Tropospheric CO2 as Measured by the Atmospheric Infrared Sounder (AIRS)

    Science.gov (United States)

    Pagano, Thomas S.; Olsen, Edward T.; Nguyen, Hai

    2012-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the Earth Observing System (EOS) Aqua Spacecraft, launched on May 4, 2002 into a near polar sun-synchronous orbit. AIRS has 2378 infrared channels ranging from 3.7 ?m to 15.4 ?m and a 13.5 km footprint at nadir. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy on a global scale, as well as water vapor profiles and trace gas amounts for CO2, CO, SO2, O3 and CH4. AIRS CO2 climatologies have been shown to be useful for identifying anomalies associated with geophysical events such as El Nino-Southern Oscillation or Madden-Julian oscillation. In this study, monthly representations of mid-tropospheric CO2 are constructed from 10 years of AIRS Version 5 monthly Level 3 data. We compare the AIRS mid-tropospheric CO2 representations to ground-based measurements from the Scripps and National Oceanic and Atmospheric Administration Climate Modeling and Diagnostics Laboratory (NOAA CMDL) ground networks to better understand the phase lag of the CO2 seasonal cycle between the surface and middle troposphere. Results show only a small phase lag in the tropics that grows to approximately two months in the northern latitudes.

  6. Application of Spaceborne Infrared Atmospheric Sounder for Geosynchronous Earth Orbit (SIRAS-G) technology to future Earth science missions

    Science.gov (United States)

    Kampe, Thomas U.

    2008-04-01

    The Spaceborne Infrared Sounder for Geosynchronous Earth Orbit (SIRAS-G) was developed by Ball Aerospace & Technologies Corp (BATC) under NASA's 2002 Instrument Incubator Program. SIRAS-G was a technology development program focused on next-generation IR imaging spectrometers for sounding of the atmosphere. SIRAS-G demonstrated that the dispersive grating spectrometer is a suitable instrument architecture for this application. In addition to providing atmospheric temperature and water vapor profiles, SIRAS-G can provide trace gases concentrations, land and ocean surface temperatures and the IR mineral dust aerosol signature from satellite. The 3-year SIRAS-G IIP development effort included the successful cryogenic testing of the SIRAS-G laboratory demonstration spectrometer operating in the 2083 to 2994 cm -1 frequency range. The performance of the demonstration instrument has been quantified including measurement of keystone distortion, spectral smile, MTF, and the spectral response function (SRF). Development efforts associated with this advanced infrared spectrometer technology provides the basis for instrumentation to support future Earth science missions.

  7. The Atmospheric Infrared Sounder (AIRS) on the NASA Aqua Spacecraft: A General Remote Sensing Tool for Understanding Atmospheric Structure, Dynamics and Composition

    Science.gov (United States)

    Pagano, Thomas S.; Chahine, Moustafa T.; Fetzer, Eric J.

    2010-01-01

    The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. Early in the mission, the AIRS instrument demonstrated its value to the weather forecasting community with better than 6 hours of improvement on the 5 day forecast. Now with over eight years of consistent and stable data from AIRS, scientists are able to examine processes governing weather and climate and look at seasonal and interannual trends from the AIRSdata with high statistical confidence. Naturally, long-term climate trends require a longer data set, but indications are that the Aqua spacecraft and the AIRS instrument should last beyond 2018. This paper briefly describes the AIRS data products and presents some of the most significant findings involving the use of AIRS data in the areas of weather forecast improvement, climate processes and model validation, cloud and polar processes, and atmospheric composition (chemistry and dust).

  8. Temporal and zonal variability and of mid-tropospheric carbon dioxide from the Atmospheric Infrared Sounder compared to surface measurements

    Science.gov (United States)

    Pagano, T. S.; Olsen, E. T.; Nguyen, H. M.; Jiang, X.

    2012-12-01

    The Atmospheric Infrared Sounder (AIRS) on the EOS Aqua Spacecraft was launched on May 4, 2002. AIRS acquires hyperspectral infrared radiances in the 3.7-15.4 um spectral region with spectral resolution of better than 1200, and spatial resolution of 13.5 km with global daily coverage. The AIRS was designed to measure temperature and water vapor profiles for improvement in weather forecast and improved parameterization of climate processes. Currently the AIRS Level 1B Radiance Products are assimilated by NWP centers worldwide and have shown considerable forecast improvement. AIRS L1 and L2 products are widely used for studying critical climate processes related to water vapor feedback, atmospheric transport and cloud properties. AIRS trace gas products include ozone profiles, carbon monoxide, and the first global maps of mid-tropospheric carbon dioxide. The global daily coverage of AIRS allows scientists to follow the transport of these gases to aid in validation of chemical/weather transport models. AIRS mid-tropospheric carbon dioxide has a peak sensitivity of about 450 mb and a width of about 500 mb. This broad mid-tropospheric sensitivity is useful for identifying global circulation patterns including ENSO (Jiang et al., 2010) and MJO (Li et al., 2010). Climatologies were developed that represent averages of AIRS Monthly L3 CO2 data detrended and averaged over the individual months for 12 maps on 2.0 x 2.5 degree grid scale (Pagano, 2011). The climatologies show a persistent low in the CO2 in the South Atlantic due to a constant downward flux from the Walker Circulation. The significantly reduced noise level in the climatologies also reveal that the horizontal variability in the AIRS CO2 measurements is not entirely driven by global circulation, but also the underlying global vegetation cycle. Further investigation into the seasonal behavior of the zonal averages of AIRS CO2, AIRS mid-troposphere and surface temperature data, MODIS derived GPP, and other ground

  9. Characteristics of water-vapour inversions observed over the Arctic by Atmospheric Infrared Sounder (AIRS and radiosondes

    Directory of Open Access Journals (Sweden)

    A. Devasthale

    2011-05-01

    Full Text Available An accurate characterization of the vertical structure of the Arctic atmosphere is useful in climate change and attribution studies as well as for the climate modelling community to improve projections of future climate over this highly sensitive region. Here, we investigate one of the dominant features of the vertical structure of the Arctic atmosphere, i.e. water-vapour inversions, using eight years of Atmospheric Infrared Sounder data (2002–2010 and radiosounding profiles released from the two Arctic locations (North Slope of Alaska at Barrow and during SHEBA. We quantify the characteristics of clear-sky water vapour inversions in terms of their frequency of occurrence, strength and height covering the entire Arctic for the first time.

    We found that the frequency of occurrence of water-vapour inversions is highest during winter and lowest during summer. The inversion strength is, however, higher during summer. The observed peaks in the median inversion-layer heights are higher during the winter half of the year, at around 850 hPa over most of the Arctic Ocean, Siberia and the Canadian Archipelago, while being around 925 hPa during most of the summer half of the year over the Arctic Ocean. The radiosounding profiles agree with the frequency, location and strength of water-vapour inversions in the Pacific sector of the Arctic. In addition, the radiosoundings indicate that multiple inversions are the norm with relatively few cases without inversions. The amount of precipitable water within the water-vapour inversion structures is estimated and we find a distinct, two-mode contribution to the total column precipitable water. These results suggest that water-vapour inversions are a significant source to the column thermodynamics, especially during the colder winter and spring seasons. We argue that these inversions are a robust metric to test the reproducibility of thermodynamics within climate models. An accurate statistical

  10. Demonstrating the Operational Value of Atmospheric Infrared Sounder (AIRS) Retrieved Profiles in the Pre-Convective Environment

    Science.gov (United States)

    Kozlowski, Danielle M.; Zavodsky, T.; Jedloved, Gary J.

    2011-01-01

    The Short-term Prediction Research and Transition Center (SPoRT) is a collaborative partnership between NASA and operational forecasting partners, including a number of National Weather Service offices. SPoRT provides real-time NASA products and capabilities to its partners to address specific operational forecast challenges. One operational forecast challenge is forecasting convective weather in data-void regions such as large bodies of water (e.g. Gulf of Mexico). To address this forecast challenge, SPoRT produces a twice-daily three-dimensional analysis that blends a model first-guess from the Advanced Research Weather Research and Forecasting (WRF-ARW) model with retrieved profiles from the Atmospheric Infrared Sounder (AIRS) -- a hyperspectral sounding instrument aboard NASA's Aqua satellite that provides temperature and moisture profiles of the atmosphere. AIRS profiles are unique in that they give a three dimensional view of the atmosphere that is not available through the current rawinsonde network. AIRS has two overpass swaths across North America each day, one valid in the 0700-0900 UTC timeframe and the other in the 1900-2100 UTC timeframe. This is helpful because the rawinsonde network only has data from 0000 UTC and 1200 UTC at specific land-based locations. Comparing the AIRS analysis product with control analyses that include no AIRS data demonstrates the value of the retrieved profiles to situational awareness for the pre-convective (and convective) environment. In an attempt to verify that the AIRS analysis was a good representation of the vertical structure of the atmosphere, both the AIRS and control analyses are compared to a Rapid Update Cycle (RUC) analysis used by operational forecasters. Using guidance from operational forecasters, convective available potential energy (CAPE) was determined to be a vital variable in making convective forecasts and is used herein to demonstrate the utility of the AIRS profiles in changing the vertical

  11. Improved methodology for surface and atmospheric soundings, error estimates, and quality control procedures: the atmospheric infrared sounder science team version-6 retrieval algorithm

    Science.gov (United States)

    Susskind, Joel; Blaisdell, John M.; Iredell, Lena

    2014-01-01

    The atmospheric infrared sounder (AIRS) science team version-6 AIRS/advanced microwave sounding unit (AMSU) retrieval algorithm is now operational at the Goddard Data and Information Services Center (DISC). AIRS version-6 level-2 products are generated near real time at the Goddard DISC and all level-2 and level-3 products are available starting from September 2002. Some of the significant improvements in retrieval methodology contained in the version-6 retrieval algorithm compared to that previously used in version-5 are described. In particular, the AIRS science team made major improvements with regard to the algorithms used to (1) derive surface skin temperature and surface spectral emissivity; (2) generate the initial state used to start the cloud clearing and retrieval procedures; and (3) derive error estimates and use them for quality control. Significant improvements have also been made in the generation of cloud parameters. In addition to the basic AIRS/AMSU mode, version-6 also operates in an AIRS only (AO) mode, which produces results almost as good as those of the full AIRS/AMSU mode. The improvements of some AIRS version-6 and version-6 AO products compared to those obtained using version-5 are also demonstrated.

  12. GRIPS - The Geostationary Remote Infrared Pollution Sounder

    Science.gov (United States)

    Spackman, Ryan; Dickerson, Russell; Schoeberl, Mark; Bloom, Hal; Gordley, Larry; McHugh, Martin; Thompson, Anne; Burrows, John; Zeng, Ning; Marshall, Tom; Fish, Chad; Kim, Jhoon; Park, Rokjin; Warner, Juying; Bhartia, Pawan; Kollonige, Debra

    2013-04-01

    Climate change and air quality are the most pressing environmental issues of the 21st century for America and for the world as a whole. Despite decades of research, the sources and sinks of key greenhouse gases and other pollutants remain highly uncertain making atmospheric composition predictions difficult. The Geostationary Remote Infrared Pollution Sounder (GRIPS) will measure carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4). By using measurements of nitrous oxide (N2O) and the O2 A-band to help correct for clouds and aerosols, GRIPS will achieve unprecedented precision. Together these gases account for about 85% of all climate forcing and they impact atmospheric ozone (O3). GRIPS, employing gas-filter correlation radiometry, uses the target gases themselves in place of dispersive elements to achieve outstanding throughput, sensitivity, and specificity. Because it uses a combination of reflected and thermal IR, GRIPS will detect trace gas concentrations right down to the Earth's surface. When flown in parallel to a UV/VIS sensor such as GEMS on GEO-KOMPSAT-2B over East Asia or the Sentinel 4 on MTG over Europe/Africa, the combination offers powerful finger-printing capabilities to distinguish and quantify diverse pollution sources such as electricity generation, biomass burning, and motor vehicles. From geostationary orbit, GRIPS will be able to focus on important targets to quantify sources, net flux, diurnal cycles, and long-range transport of these key components in the Earth's radiative balance and air quality.

  13. Large Scale Variability of Mid-Tropospheric Carbon Dioxide as Observed by the Atmospheric Infrared Sounder (AIRS) on the NASA EOS Aqua Platform

    Science.gov (United States)

    Pagano, Thomas S.; Olsen, Edward T.

    2012-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral infrared instrument on the EOS Aqua Spacecraft, launched on May 4, 2002. AIRS has 2378 infrared channels ranging from 3.7 microns to 15.4 microns and a 13.5 km footprint. AIRS, in conjunction with the Advanced Microwave Sounding Unit (AMSU), produces temperature profiles with 1K/km accuracy, water vapor profiles (20%/2km), infrared cloud height and fraction, and trace gas amounts for CO2, CO, SO2, O3 and CH4 in the mid to upper troposphere. AIRS wide swath(cedilla) +/-49.5 deg , enables daily global daily coverage for over 95% of the Earth's surface. AIRS data are used for weather forecasting, validating climate model distribution and processes, and observing long-range transport of greenhouse gases. In this study, we examine the large scale and regional horizontal variability in the AIRS Mid-tropospheric Carbon Dioxide product as a function of season and associate the observed variability with known atmospheric transport processes, and sources and sinks of CO2.

  14. A 6-year global climatology of occurrence of upper-tropospheric ice supersaturation inferred from the Atmospheric Infrared Sounder after synergetic calibration with MOZAIC

    Directory of Open Access Journals (Sweden)

    N. Lamquin

    2011-04-01

    Full Text Available Ice supersaturation in the upper troposphere is a complex and important issue for the understanding of cirrus cloud formation. Infrared sounders have the ability to provide cloud properties and atmospheric profiles of temperature and humidity. On the other hand, they suffer from coarse vertical resolution, especially in the upper troposphere and therefore are unable to detect shallow ice supersaturated layers. We have used data from the Measurements of OZone and water vapour by AIrbus in-service airCraft experiment (MOZAIC in combination with Atmospheric InfraRed Sounder (AIRS relative humidity measurements and cloud properties to develop a calibration method for an estimation of occurrence frequencies of ice supersaturation. This method first determines the occurrence probability of ice supersaturation, detected by MOZAIC, as a function of the relative humidity determined by AIRS. The occurrence probability function is then applied to AIRS data, independently of the MOZAIC data, to provide a global climatology of upper-tropospheric ice supersaturation occurrence. Our climatology is then related to high cloud occurrence from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP and compared to ice supersaturation occurrence statistics from MOZAIC alone. Finally it is compared to model climatologies of ice supersaturation from the Integrated Forecast System (IFS of the European Centre for Medium-Range Weather Forecasts (ECMWF and from the European Centre HAmburg Model (ECHAM. All the comparisons show good agreements when considering the limitations of each instrument and model. This study highlights the benefits of multi-instrumental synergies for the investigation of upper tropospheric ice supersaturation.

  15. A 6-year global cloud climatology from the Atmospheric InfraRed Sounder AIRS and a statistical analysis in synergy with CALIPSO and CloudSat

    Directory of Open Access Journals (Sweden)

    S. Cros

    2010-08-01

    Full Text Available We present a six-year global climatology of cloud properties, obtained from observations of the Atmospheric Infrared Sounder (AIRS onboard the NASA Aqua satellite. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO combined with CloudSat observations, both missions launched as part of the A-Train in 2006, provide a unique opportunity to evaluate the retrieved AIRS cloud properties such as cloud amount and height. In addition, they permit to explore the vertical structure of different cloud types. AIRS-LMD cloud detection agrees with CALIPSO about 85% over ocean and about 75% over land. Global cloud amount has been estimated from 66% to 74%, depending on the weighting of not cloudy AIRS footprints by partial cloud cover from 0 to 0.3. 42% of all clouds are high clouds, and about 42% of all clouds are single layer low-level clouds. The "radiative" cloud height determined by the AIRS-LMD retrieval corresponds well to the height of the maximum backscatter signal and of the "apparent middle" of the cloud. Whereas the real cloud thickness of high opaque clouds often fills the whole troposphere, their "apparent" cloud thickness (at which optical depth reaches about 5 is on average only 2.5 km. The real geometrical thickness of optically thin cirrus as identified by AIRS-LMD is identical to the "apparent" cloud thickness with an average of about 2.5 km in the tropics and midlatitudes. High clouds in the tropics have slightly more diffusive cloud tops than at higher latitudes. In general, the depth of the maximum backscatter signal increases nearly linearly with increasing "apparent" cloud thickness. For the same "apparent" cloud thickness optically thin cirrus show a maximum backscatter about 10% deeper inside the cloud than optically thicker clouds. We also show that only the geometrically thickest opaque clouds and (the probably surrounding anvil cirrus penetrate the stratosphere in the tropics.

  16. A 6-year global cloud climatology from the Atmospheric InfraRed Sounder AIRS and a statistical analysis in synergy with CALIPSO and CloudSat

    Directory of Open Access Journals (Sweden)

    C. J. Stubenrauch

    2010-03-01

    Full Text Available We present a six-year global climatology of cloud properties, obtained from observations of the Atmospheric Infrared Sounder (AIRS onboard the NASA Aqua satellite. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO combined with CloudSat observations, both missions launched as part of the A-Train in 2006, provide a unique opportunity to evaluate the retrieved AIRS cloud properties such as cloud amount and height as well as to explore the vertical structure of different cloud types. AIRS-LMD cloud detection agrees with CALIPSO about 85% over ocean and about 75% over land. Global cloud amount has been estimated as about 66% to 74%, depending on the weighting of not cloudy AIRS footprints by partial cloud cover (0 or 0.3. 40% of all clouds are high clouds, and about 44% of all clouds are single layer low-level clouds. The "radiative" cloud height determined by the AIRS-LMD retrieval corresponds well to the height of the maximum backscatter signal and of the "apparent middle" of the cloud. Whereas the real cloud thickness of high opaque clouds often fills the whole troposphere, their "apparent" cloud thickness (at which optical depth reaches about 5 is on average only 2.5 km. The real geometrical thickness of optically thin cirrus as identified by AIRS-LMD is identical to the "apparent" cloud thickness with an average of about 2.5 km in the tropics and midlatitudes. High clouds in the tropics have slightly more diffusive cloud tops than at higher latitudes. In general, the depth of the maximum backscatter signal increases nearly linearly with increasing "apparent" cloud thickness. For the same "apparent" cloud thickness optically thin cirrus show a maximum backscatter about 10% deeper inside the cloud than optically thicker clouds. We also show that only the geometrically thickest opaque clouds and (the probably surrounding anvil cirrus penetrate the stratosphere in the tropics.

  17. A Simple Drought Product and Indicator Derived from Temperature and Relative Humidity Observed by the Atmospheric InfraRed Sounder (AIRS)

    Science.gov (United States)

    Granger, S. L.; Behrangi, A.

    2015-12-01

    In the United States, drought results in agricultural losses, impacts to industry, power and energy production, natural resources, municipal water supplies and human health making it one of the costliest natural hazards in the nation. Monitoring drought is therefore critical to help local governments, resource managers, and other groups make effective decisions, yet there is no single definition of drought, and because of the complex nature of drought there is no universal best drought indicator. Remote sensing applications in drought monitoring are advantageous due to the large spatial and temporal frequency of observations, leading to a better understanding of the spatial extent of drought and its duration, and in detecting the onset of drought and its intensity. NASA Earth Observing System (EOS)-era data have potential for monitoring and assessing drought and many are already used either directly or indirectly for drought monitoring. Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) observations from the Moderate Resolution Imaging Spectro-radiometer (MODIS) sensor are widely used for agricultural and environmental plant-stress monitoring via the USDM, the VegDRI project and FEWSNet. However there remain underutilized sources of information from NASA satellite observations that may have promise for characterizing and understanding meteorological drought. Once such sensor is NASA's Advanced Infra-Red Sounder (AIRS) aboard the Aqua satellite. AIRS and it's sister sensor the Advanced Microwave Sounding Unit (AMSU) that together provide meteorological information of high relevance to meteorological drought, e.g., profiles of water vapor, surface air temperature, and precipitation. Recent work undertaken to develop simple indicators of drought based on temperature and relative humidity from the AIRS suite of instruments is promising. Although there are more sophisticated indicators developed through the application of a variety of

  18. Estimation of volcanic ash refractive index from satellite infrared sounder data

    Science.gov (United States)

    Ishimoto, H.; Masuda, K.

    2014-12-01

    The properties of volcanic ash clouds (cloud height, optical depth, and effective radius of the particles) are planned to estimate from the data of the next Japanese geostationary meteorological satellite, Himawari 8/9. The volcanic ash algorithms, such as those proposed by NOAA/NESDIS and by EUMETSAT, are based on the infrared absorption properties of the ash particles, and the refractive index of a typical volcanic rock (i.e. andesite) has been used in the forward radiative transfer calculations. Because of a variety of the absorption properties for real volcanic ash particles at infrared wavelengths (9-13 micron), a large retrieval error may occur if the refractive index of the observed ash particles was different from that assumed in the retrieval algorithm. Satellite infrared sounder provides spectral information for the volcanic ash clouds. If we can estimate the refractive index of the ash particles from the infrared sounder data, a dataset of the optical properties for similar rock type of the volcanic ash can be prepared for the ash retrieval algorithms of geostationary/polar-orbiting satellites in advance. Furthermore, the estimated refractive index can be used for a diagnostic and a correction of the ash particle model in the retrieval algorithm within a period of the volcanic activities. In this work, optimal estimation of the volcanic ash parameters was conducted through the radiative transfer calculations for the window channels of the atmospheric infrared sounder (AIRS). The estimated refractive indices are proposed for the volcanic ash particles of some eruption events.

  19. NOAA Climate Data Record (CDR) of Intersatellite Calibrated Clear-Sky High Resolution Infrared Radiation Sounder (HIRS) Channel 12 Brightness Temperature Version 3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The High-Resolution Infrared Radiation Sounder (HIRS) of intersatellite calibrated channel 12 brightness temperature (TB) product is a gridded global monthly time...

  20. Inter-Comparison of S-NPP VIIRS and Aqua MODIS Thermal Emissive Bands Using Hyperspectral Infrared Sounder Measurements as a Transfer Reference

    OpenAIRE

    Yonghong Li; Aisheng Wu; Xiaoxiong Xiong

    2016-01-01

    This paper compares the calibration consistency of the spectrally-matched thermal emissive bands (TEB) between the Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) and the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS), using observations from their simultaneous nadir overpasses (SNO). Nearly-simultaneous hyperspectral measurements from the Aqua Atmospheric Infrared Sounder(AIRS) and the S-NPP Cross-track Infrared Sounder (CrIS) a...

  1. Requirements for a Moderate-resolution Infrared Imaging Sounder (MIRIS)

    Science.gov (United States)

    Pagano, Thomas S.; Aumann, Hartmut H.; Gerber, Andrew J.; Kuai, Le; Gontijo, I.; DeLeon, Berta; Susskind, Joel; Iredell, Lena; Bajpai, Shyam

    2013-09-01

    The high cost of imaging and sounding from space warrants exploration of new methods for obtaining the required information, including changing the spectral band sets, employing new technologies and merging instruments. In some cases we must consider relaxation of the current capability. In others, we expect higher performance. In general our goal is to meet the VIIRS and CrIS requirements while providing the enhanced next generation capabilities: 1) Hyperspectral Imaging in the Vis/NIR bands, 2) High Spatial Resolution Sounding in the Infrared bands. The former will improve the accuracy of ocean color products, aerosols and water vapor, surface vegetation and geology. The latter will enable the high-impact achieved by the current suite of hyperspectral infrared sounders to be achieved by the next generation high resolution forecast models. We examine the spectral, spatial and radiometric requirements for a next generation system and technologies that can be applied from the available inventory within government and industry. A two-band grating spectrometer instrument called the Moderate-resolution Infrared Imaging Sounder (MIRIS) is conceived that, when used with the planned NASA PACE Ocean Color Instrument (OCI) will meet the vast majority of CrIS and VIIRS requirements in the all bands and provide the next generation capabilities desired. MIRIS resource requirements are modest and the Technology Readiness Level is high leading to the expectation that the cost and risk of MIRIS will be reasonable.

  2. Community Radiative Transfer Model Applications - A Study of the Retrieval of Trace Gases in the Atmosphere from Cross-track Infrared Sounder (CrIS) Data of a Full-spectral Resolution

    Science.gov (United States)

    Liu, Q.; Nalli, N. R.; Tan, C.; Zhang, K.; Iturbide, F.; Wilson, M.; Zhou, L.

    2015-12-01

    The Community Radiative Transfer Model (CRTM) [3] operationally supports satellite radiance assimilation for weather forecasting, sensor data verification, and the retrievals of satellite products. The CRTM has been applied to UV and visible sensors, infrared and microwave sensors. The paper will demonstrate the applications of the CRTM, in particular radiative transfer in the retrieva algorithm. The NOAA Unique CrIS/ATMS Processing System (NUCAPS) operationally generates vertical profiles of atmospheric temperature (AVTP) and moisture (AVMP) from Suomi NPP Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) measurements. Current operational CrIS data have reduced spectral resolution: 1.25 cm-1 for a middle wave band and 2.5 cm-1 for a short-wave wave band [1]. The reduced spectral data largely degraded the retrieval accuracy of trace gases. CrIS full spectral data are also available now which have single spectral resolution of 0.625 cm-1 for all of the three bands: long-wave band, middle wave band, and short-wave band. The CrIS full-spectral resolution data is critical to the retrieval of trace gases such as O3, CO [2], CO2, and CH4. In this paper, we use the Community Radiative Transfer Model (CRTM) to study the impact of the CrIS spectral resolution on the retrieval accuracy of trace gases. The newly released CRTM version 2.2.1 can simulates Hamming-apodized CrIS radiance of a full-spectral resolution. We developed a small utility that can convert the CRTM simulated radiance to un-apodized radiance. The latter has better spectral information which can be helpful to the retrievals of the trace gases. The retrievals will be validated using both NWP model data as well as the data collected during AEROSE expeditions [4]. We will also discuss the sensitivity on trace gases between apodized and un-apodized radiances. References[1] Gambacorta, A., et al.(2013), IEEE Lett., 11(9), doi:10.1109/LGRS.2014.230364, 1639-1643. [2] Han, Y., et

  3. Low Cost Upper Atmosphere Sounder (LOCUS)

    Science.gov (United States)

    Gerber, Daniel; Swinyard, Bruce M.; Ellison, Brian N.; Aylward, Alan D.; Aruliah, Anasuya; Plane, John M. C.; Feng, Wuhu; Saunders, Christopher; Friend, Jonathan; Bird, Rachel; Linfield, Edmund H.; Davies, A. Giles; Parkes, Steve

    2014-05-01

    The Mesosphere - Lower Thermosphere region (MLT) is often quoted as being the least well known region of the atmosphere, meaning that measurements of this altitude range are sparser than for the neighbouring layers. The reason for this apparent lack of observations can be traced back to a combination of two facts - A) the MLT is ill suited for in-situ sampling on a global scale because the residual air drag is prohibitive for suborbital vehicles (rockets are traditionally used to sample the MLT region, but they only provide snapshot measurements both geographically, as well as temporally), and B) Some of the most important trace gases in the MLT have spectral emission lines in the THz range, a frequency band which has only just become accessible to conventional remote sensing technologies (i.e. passive heterodyne detection) thanks to ongoing technology development, but which still poses massive - often prohibitive - demands on the complexity, weight and power consumption of satellite borne remote sensing detectors. To mitigate the substantial power requirements of a Local Oscillator (LO) able to pump a heterodyne receiver at THZ frequencies, we are suggesting the use of Quantum Cascade Laser diodes (QCL). Combining a QCL LO with a sub-harmonic Schottky mixer in an integrated receiver system would allow us to build a THz passive heterodyne detector for atmospheric remote sensing that is both very compact and power efficient, and could therefore be built and launched much more cheaply than competitive systems. Many of the technologies required for such an instrument already exist at technology readiness levels (TRL) of 3-5. A consortium of RAL Space, University College London (UCL), University of Leeds, Surrey Satellite Technology Ltd (SSTL) and STAR-Dundee have been awarded a grant through the ESA In Orbit Demonstration Programme (IOD) to start developing an integrated, sub-harmonic heterodyne receiver with a QCL LO up to a TRL that would allow IOD hopefully in the

  4. Calibration and Validation of the InfraRed Atmospheric Sounder Onboard the FY3B Satellite%风云三号B星红外分光计的定标和验证

    Institute of Scientific and Technical Information of China (English)

    漆成莉; 陈勇; 刘辉; 吴春强; 殷德奎

    2013-01-01

    InfraRed Atmospheric Sounder (IRAS) instruments were successfully launched onboard the FengYun-3A (FY3A) and FengYun-3B (FY3B) satellites on May 27, 2008, and November 5, 2010, respectively. They aim at providing multichannel radiances within the spectral range of visible to infrared (IR) wavelengths for many environmental applications, including data assimilation and retrievals of global atmospheric temperature and humidity proifles. However, the velocity of the iflter wheel of the ifrst IRAS onboard FY3A is unstable and, therefore, induced a discontinuity in the measurement. The IRAS onboard FY3B works well in normal and stable operational mode since its launch without any anomaly. A variety of postlaunch calibration/validation tasks are conducted using on-orbit data during a period of three months. This paper presents on-orbit veriifcation of IRAS instrument performance, including long-term trends of the space and warm calibration counts and noise equivalent delta radiance. The Earth scenes observed simultaneously by IRAS and Meteorological Operational Satellite Programme (METOP)/Infrared Atmospheric Sounding Interferometer were obtained and compared to demonstrate a close similarity between the two measurements. Furthermore, the IR channel observations from FY3B/IRAS are compared with those from National Oceanic and Atmospheric Administration-19/High Resolution Infrared Radiation Sounder (HIRS) equivalent channels and simulations from a radiative transfer model. The results show that some of IRAS IR channels perform very well, particularly for channels 1-10, 15, 19, and 20, compared to those of HIRS. Several channels, such as 13, 16, and 18, however, display some large biases. The causes of these increased biases are still under investigation.%搭载于风云三号A星和B星上的红外分光计(IRAS)分别于2008年5月27日和2010年11月5日成功发射。该仪器主要提供从可见光到红外波长范围内多通道的辐射观测,并可

  5. Tomographic retrieval approach for mesoscale gravity wave observations by the PREMIER Infrared Limb-Sounder

    Directory of Open Access Journals (Sweden)

    J. Ungermann

    2010-03-01

    Full Text Available PREMIER is one of three candidates for ESA's 7th Earth Explorer mission that are currently undergoing feasibility studies. The main mission objective of PREMIER is to quantify processes controlling atmospheric composition in the mid/upper troposphere and lower stratosphere, a region of particular importance for climate change. To achieve this objective, PREMIER will employ the first satellite Fourier transform infrared limb-imager with a 2-D detector array combined with a millimetre-wave limb-sounder. The infrared limb-imager can be operated in a high spatial resolution mode ("dynamics mode" for observations of small-scale structures in atmospheric temperatures and trace gas fields with unprecedented 3-D sampling (0.5 km in the vertical direction, 50 km along track, 25 km across track. In this paper, a fast tomographic retrieval scheme is presented, which is designed to fully exploit the high-resolution radiance observations of the dynamics mode. Based on a detailed analysis of the "observational filter", we show that the dynamics mode provides unique information on global distributions of gravity waves (GW. The achievable vertical resolution for GW observations has values between the vertical sampling (0.5 km of the dynamics mode and the vertical field of view (about 0.75 km. The horizontal across track resolution corresponds to the horizontal across track sampling of 25 km. Since the achievable along track horizontal resolution is about 70 km, the dynamics mode will provide GW limb-observations with a horizontal resolution comparable to nadir sounders. Compared to previous observations, PREMIER will therefore considerably extend the range of detectable GWs in terms of horizontal and vertical wavelength.

  6. An artificial neural network based fast radiative transfer model for simulating infrared sounder radiances

    Indian Academy of Sciences (India)

    Praveen Krishnan; K Srinivasa Ramanujam; C Balaji

    2012-08-01

    The first step in developing any algorithm to retrieve the atmospheric temperature and humidity parameters at various pressure levels is the simulation of the top of the atmosphere radiances that can be measured by the satellite. This study reports the results of radiative transfer simulations for the multichannel infrared sounder of the proposed Indian satellite INSAT-3D due to be launched shortly. Here, the widely used community software k Compressed Atmospheric Radiative Transfer Algorithm (kCARTA) is employed for performing the radiative transfer simulations. Though well established and benchmarked, kCARTA is a line-by-line solver and hence takes enormous computational time and effort for simulating the multispectral radiances for a given atmospheric scene. This necessitates the development of a much faster and at the same time, equally accurate RT model that can drive a real-time retrieval algorithm. In the present study, a fast radiative transfer model using neural networks is proposed to simulate radiances corresponding to the wavenumbers of INSAT-3D. Realistic atmospheric temperature and humidity profiles have been used for training the network. Spectral response functions of GOES-13, a satellite similar in construction, purpose and design and already in use are used. The fast RT model is able to simulate the radiances for 1200 profiles in 18 ms for a 15-channel GOES profile, with a correlation coefficient of over 99%. Finally, the robustness of the model is tested using additional synthetic profiles generated using empirical orthogonal functions (EOF).

  7. Suomi NPP/JPSS Cross-track Infrared Sounder (CrIS): Calibration Validation With The Aircraft Based Scanning High-resolution Interferometer Sounder (S-HIS)

    Science.gov (United States)

    Taylor, J. K.; Revercomb, H. E.; Tobin, D.; Knuteson, R. O.; Best, F. A.; Adler, D. A.; Pettersen, C.; Garcia, R. K.; Gero, P.

    2013-12-01

    To better accommodate climate change monitoring and improved weather forecasting, there is an established need for higher accuracy and more refined error characterization of radiance measurements from space and the corresponding geophysical products. This need has led to emphasizing direct tests of on-orbit performance, referred to as validation. Currently, validation typically involves (1) collecting high quality reference data from airborne and/or ground-based instruments during the satellite overpass, and (2) a detailed comparison between the satellite-based radiance measurements and the corresponding high quality reference data. Additionally, for future missions technology advancements at the University of Wisconsin Space Science and Engineering Center (UW-SSEC) have led to the development of an on-orbit absolute radiance reference utilizing miniature phase change cells to provide direct on-orbit traceability to International Standards (SI). The detailed comparison between the satellite-based radiance measurements and the corresponding measurements made from a high-altitude aircraft must account for instrument noise and scene variations, as well as differences in instrument observation altitudes, view angles, spatial footprints, and spectral response. Most importantly, for the calibration validation process to be both accurate and repeatable the reference data instrument must be extremely well characterized and understood, carefully maintained, and accurately calibrated, with traceability to absolute standards. The Scanning High-resolution Interferometer Sounder (S-HIS) meets and exceeds these requirements and has proven to do so on multiple airborne platforms, each with significantly different instrument operating environments. The Cross-track Infrared Sounder (CrIS) on Suomi NPP, launched 28 October 2011, is designed to give scientists more refined information about Earth's atmosphere and improve weather forecasts and our understanding of climate. CrIS is an

  8. Probing Mars’ atmosphere with ExoMars Mars Climate Sounder

    OpenAIRE

    Irwin, Patrick G. J.; Calcutt, S.B.; P. L. Read; Bowles, N E; Lewis, S

    2011-01-01

    The 2016 Mars Trace Gas Mission will carry with it the ExoMars Mars Climate Sounder instrument, a development of the very successful Mars Climate Sounder instrument already in orbit about Mars on NASA's Mars Reconnaissance Orbiter spacecraft. EMCS will continue the monitoring of Mars global temperature/pressure/aerosol field, and will also be able to measure the vertical profile of water vapour across the planet from 0 – 50 km. Key components of EMCS will be provided by Oxford, Reading and Ca...

  9. Retrievals with the Infrared Atmospheric Sounding Interferometer

    Science.gov (United States)

    Zhou, Daniel K.; Liu, Xu; Larar, Allen M.; Smith, William L.; Taylor, Jonathan P.; Schlussel, Peter; Strow, L. Larrabee; Calbet, Xavier; Mango, Stephen A.

    2007-01-01

    The Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite was launched on October 19, 2006. The Joint Airborne IASI Validation Experiment (JAIVEx) was conducted during April 2007 mainly for validation of the IASI on the MetOp satellite. IASI possesses an ultra-spectral resolution of 0.25/cm and a spectral coverage from 645 to 2760/cm. Ultraspectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. An advanced retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. Preliminary retrievals of atmospheric soundings, surface properties, and cloud optical/microphysical properties with the IASI observations during the JAIVEx are obtained and presented. These retrievals are further inter-compared with those obtained from airborne FTS system, such as the NPOESS Airborne Sounder Testbed Interferometer (NAST-I), dedicated dropsondes, radiosondes, and ground based Raman Lidar. The capabilities of satellite ultra-spectral sounder such as the IASI are investigated.

  10. Ultraspectral sounder data compression review

    Institute of Scientific and Technical Information of China (English)

    Bormin HUANG; Hunglung HUANG

    2008-01-01

    Ultraspectral sounders provide an enormous amount of measurements to advance our knowledge of weather and climate applications. The use of robust data compression techniques will be beneficial for ultraspectral data transfer and archiving. This paper reviews the progress in lossless compression of ultra-spectral sounder data. Various transform-based, pre-diction-based, and clustering-based compression methods are covered. Also studied is a preprocessing scheme for data reordering to improve compression gains. All the coding experiments are performed on the ultraspectral compression benchmark dataset col-lected from the NASA Atmospheric Infrared Sounder (AIRS) observations.

  11. Cross-track Infrared Sounder (CrIS satellite observations of tropospheric ammonia

    Directory of Open Access Journals (Sweden)

    M. W. Shephard

    2014-11-01

    Full Text Available Observations of atmospheric ammonia are important in understanding and modeling the impact of ammonia on both human health and the natural environment. Presented is a detailed description of a robust retrieval algorithm that demonstrates the capabilities of utilizing Cross-track Infrared Sounder (CrIS satellite observations to globally retrieval ammonia concentrations. Initial ammonia retrieval results using both simulated and real observations show that CrIS is: (i sensitive to ammonia in the boundary layer, with peak vertical sensitivity typically around 800 hPa (~2 km, (ii has a minimum detection limit of ~1 ppbv (peak profile value, and (iii the information content can vary significantly with peak values of ~1 degrees-of-freedom for signal. Comparisons of the retrieval with simulated "true" profiles show there is small positive retrieval bias of 6%, with the variability being from 4% (25th quartile to +26% (75th quartile. Note these uncertainty estimates are considered as lower bound values as no potential systematic errors are included in the simulations. The CrIS NH3 retrieval applied over the Central Valley in CA, USA demonstrates that CrIS can capture the general spatial variability of the boundary layer ammonia concentrations seen by the nearby Quantum Cascade-Laser (QCL in-situ surface and the Tropospheric Emission Spectrometer (TES satellite observations as part of the DISCOVER-AQ campaign. The CrIS and TES ammonia observations show quantitatively similar retrieved boundary layer values that are often within the uncertainty of the two observations. These initial results demonstrate the capabilities of the CrIS satellite to measure ammonia.

  12. Hyperspectral Microwave Atmospheric Sounder (HyMAS) architecture and design accommodations

    Science.gov (United States)

    Hilliard, L.; Racette, P.; Blackwell, W.; Galbraith, C.; Thompson, E.

    The Hyperspectral Microwave Atmospheric Sounder (HyMAS) is being developed at Lincoln Laboratories and accommodated by the Goddard Space Flight Center for a flight opportunity on a NASA research aircraft. The term “ hyperspectral microwave” is used to indicate an all-weather sounding that performs equivalent to hyperspectral infrared sounders in clear air with vertical resolution of approximately 1 km. Deploying the HyMAS equipped scanhead with the existing Conical Scanning Microwave Imaging Radiometer (CoSMIR) shortens the path to a flight demonstration. Hyperspectral microwave is achieved through the use of independent RF antennas that sample the volume of the Earth's atmosphere through various levels of frequencies, thereby producing a set of dense, spaced vertical weighting functions. The simulations proposed for HyMAS 118/183-GHz system should yield surface precipitation rate and water path retrievals for small hail, soft hail, or snow pellets, snow, rainwater, etc. with accuracies comparable to those of the Advanced Technology Microwave Sounder. Further improvements in retrieval methodology (for example, polarization exploitation) are expected. The CoSMIR instrument is a packaging concept re-used on HyMAS to ease the integration features of the scanhead. The HyMAS scanhead will include an ultra-compact Intermediate Frequency Processor (IFP) module that is mounted inside the door to improve thermal management. The IFP is fabricated with materials made of Low-Temperature Co-fired Ceramic (LTCC) technology integrated with detectors, amplifiers, A/D conversion and data aggregation. The IFP will put out 52 channels of 16 bit data comprised of 4 - 9 channel data streams for temperature profiles and 2-8 channel streams for water vapor. With the limited volume of the existing CoSMIR scanhead and new HyMAS front end components, the HyMAS team at Goddard began preliminary layout work inside the new drum. Importing and re-using models of the shell, the s- an head

  13. Hyperspectral Microwave Atmospheric Sounder (HyMAS) Architecture and Design Accommodations

    Science.gov (United States)

    Hilliard, Lawrence; Racette, Paul; Blackwell, William; Galbraith, Christopher; Thompson, Erik

    2013-01-01

    The Hyperspectral Microwave Atmospheric Sounder (HyMAS) is being developed at Lincoln Laboratories and accommodated by the Goddard Space Flight Center for a flight opportunity on a NASA research aircraft. The term "hyperspectral microwave" is used to indicate an all-weather sounding that performs equivalent to hyperspectral infrared sounders in clear air with vertical resolution of approximately 1 km. Deploying the HyMAS equipped scanhead with the existing Conical Scanning Microwave Imaging Radiometer (CoSMIR) shortens the path to a flight demonstration. Hyperspectral microwave is achieved through the use of independent RF antennas that sample the volume of the Earth s atmosphere through various levels of frequencies, thereby producing a set of dense, spaced vertical weighting functions. The simulations proposed for HyMAS 118/183-GHz system should yield surface precipitation rate and water path retrievals for small hail, soft hail, or snow pellets, snow, rainwater, etc. with accuracies comparable to those of the Advanced Technology Microwave Sounder. Further improvements in retrieval methodology (for example, polarization exploitation) are expected. The CoSMIR instrument is a packaging concept re-used on HyMAS to ease the integration features of the scanhead. The HyMAS scanhead will include an ultra-compact Intermediate Frequency Processor (IFP) module that is mounted inside the door to improve thermal management. The IFP is fabricated with materials made of Low-Temperature Co-fired Ceramic (LTCC) technology integrated with detectors, amplifiers, A/D conversion and data aggregation. The IFP will put out 52 channels of 16 bit data comprised of 4-9 channel data streams for temperature profiles and 2-8 channel streams for water vapor. With the limited volume of the existing CoSMIR scanhead and new HyMAS front end components, the HyMAS team at Goddard began preliminary layout work inside the new drum. Importing and re-using models of the shell, the scan head computer

  14. Retrieving dust aerosols properties (optical depth and altitude) from very high resolution infrared sounders : from AIRS to IASI.

    Science.gov (United States)

    Peyridieu, S.; Chédin, A.; Capelle, V.; Pierangelo, C.; Lamquin, N.; Armante, R.

    2009-04-01

    Observation from space, being global and quasi-continuous, is a first importance tool for aerosol studies. Remote sensing in the visible domain has been widely used to obtain better characterization of these particles and their effect on solar radiation. On the opposite, remote sensing of aerosols in the thermal infrared domain still remains marginal. However, knowledge of the effect of aerosols on terrestrial radiation is needed for the evaluation of their total radiative forcing. Infrared remote sensing provides a way to retrieve other aerosol characteristics, including their mean altitude. Moreover, observations are possible at night and day, over ocean and over land. In this context, six years (2003-2008) of the 2nd generation vertical sounder AIRS observations have been processed over the tropical belt (30°N-30°S). Aerosol properties (10 µm infrared optical depth and mean layer altitude) are retrieved using a Look-Up Table (LUT) approach. The forward radiative transfer model 4A (Automatized Atmospheric Absorption Atlas) coupled with the DISORT algorithm accounting for atmospheric diffusion is used to feed the LUTs with simulations of the brightness temperatures of AIRS channels selected for their sensitivity to dust aerosols. LUTs degrees of freedom are : instrument viewing angle, surface pressure and surface emissivity, a parameter particularly important for dust retrieval over bright surfaces, such as deserts. AODs (resp. altitude) are sampled over the range 0.0-0.8 (resp. 0-5800 m). The retrieval algorithm follows two main steps : (i) retrieval of the atmospheric situation observed (temperature and water vapour profiles) ; (ii) retrieval of aerosol properties. Results have been compared to instruments commonly used in aerosol studies and also part of the Aqua Train : MODIS/Aqua and CALIOP/CALIPSO. The agreement obtained from these comparisons is quite satisfactory, demonstrating that our algorithm effectively allows the simultaneous retrieval of dust AOD

  15. The primary design of advanced ground-based atmospheric microwave sounder and retrieval of physical parameters

    International Nuclear Information System (INIS)

    This paper introduces a prototype of ground-based atmospheric microwave sounder that operates in K-band from 22 to 31 GHz and V-band from 51 to 59 GHz. Different from the MP3000A and RPG, the sounder adopts independent dual-band reflectors instead of sharing a dual-band reflector. The direct detect type receiver is applied, which is of smaller size, higher sensitivity, efficient data observing and lower nonlinear error than the widely used superheterodyne receiver. The observing brightness temperatures from this prototype agree well with the simulated brightness temperatures according to the ground-based radiative transfer theory. We use the artificial neural network (ANN) algorithm to retrieve temperature profiles, which has higher spatial resolution especially in the capping inversion when compared with the linear regression algorithm. The temperature retrievals are comparable with the retrievals from RPG and MP3000A retrieval models and have a smaller bias in some certain regions.

  16. Atmospheric River Observations with the HAMSR Aircraft Microwave Sounder

    Science.gov (United States)

    Lambrigtsen, B.; Brown, S. T.; Schreier, M. M.; Dang, H. V. T.; Behrangi, A.

    2015-12-01

    The High Altitude MMIC Sounding Radiometer (HAMSR) was developed at the Jet Propulsion Laboratory in 2001 to serve as an aircraft based hurricane observatory. It initially flew on the high altitude ER-2 and later on the DC-8. More recently it was modified to fly on the Global Hawk UAV. It uses the most advanced technology and is among the most sensitive instruments of its kind. In addition to a number of NASA hurricane field campaigns - mostly in the North Atlantic, HAMSR has participated in two atmospheric river campaigns off the California coast, one in 2011 (WISPAR) and one in 2015 (CalWater2). We will discuss observations from the 2015 campaign, with particular focus on a flight over an atmsospheric river making landfall in central California in early February, as well as compare with highlights from the 2011 flights. Copyright 2015 California Institute of Technology. Government sponsorship acknowledged.

  17. Thermal Tides in the Martian Middle Atmosphere as Seen by the Mars Climate Sounder

    Science.gov (United States)

    Lee, C.; Lawson, W. G.; Richardson, M. I.; Heavens, N. G.; Kleinböhl, A.; Banfield, D.; McCleese, D. J.; Zurek, R.; Kass, D.; Schofield, J. T.; Leovy, C. B.; Taylor, F. W.; Toigo, A. D.

    2016-01-01

    The first systematic observations of the middle atmosphere of Mars (35km–80km) with the Mars Climate Sounder (MCS) show dramatic patterns of diurnal thermal variation, evident in retrievals of temperature and water ice opacity. At the time of writing, the dataset of MCS limb retrievals is sufficient for spectral analysis within a limited range of latitudes and seasons. This analysis shows that these thermal variations are almost exclusively associated with a diurnal thermal tide. Using a Martian General Circulation Model to extend our analysis we show that the diurnal thermal tide dominates these patterns for all latitudes and all seasons.

  18. Sunglint Impact on Atmospheric Soundings from Hyperspectral Resolution Infrared Radiances

    Institute of Scientific and Technical Information of China (English)

    YAO Zhigang; Jun LI; Jinlong LI

    2012-01-01

    ABSTRACT The mid-wave infrared band (3-5 μm) has been widely used for atmospheric soundings.The sunglint impact on the atmospheric parameter retrieval using this band has been neglected because the reflected radiances in this band are significantly less than those in the visible band.In this study,an investigation of sunglint impact on the atmospheric soundings was conducted with Atmospheric InfraRed Sounder observation data from 1 July to 7 July 2007 over the Atlantic Ocean.The impact of sunglint can lead to a brightness temperature increase of 1.0 K for the surface sensitive sounding channels near 4.58 μm.This contamination can indirectly cause a positive bias of 4 g kg-1 in the water vapor retrieval near the ocean surface,and it can be corrected by simply excluding those contaminated channels.

  19. VISSR Atmospheric Sounder (VAS) simulation experiment for a severe storm environment

    Science.gov (United States)

    Chesters, D.; Uccellini, L. W.; Mostek, A.

    1981-01-01

    Radiance fields were simulated for prethunderstorm environments in Oklahoma to demonstrate three points: (1) significant moisture gradients can be seen directly in images of the VISSIR Atmospheric Sounder (VAS) channels; (2) temperature and moisture profiles can be retrieved from VAS radiances with sufficient accuracy to be useful for mesoscale analysis of a severe storm environment; and (3) the quality of VAS mesoscale soundings improves with conditioning by local weather statistics. The results represent the optimum retrievability of mesoscale information from VAS radiance without the use of ancillary data. The simulations suggest that VAS data will yield the best soundings when a human being classifies the scene, picks relatively clear areas for retrieval, and applies a "local" statistical data base to resolve the ambiguities of satellite observations in favor of the most probable atmospheric structure.

  20. Fast and Accurate Collocation of the Visible Infrared Imaging Radiometer Suite Measurements with Cross-Track Infrared Sounder

    Directory of Open Access Journals (Sweden)

    Likun Wang

    2016-01-01

    Full Text Available Given the fact that Cross-track Infrared Sounder (CrIS and the Visible Infrared Imaging Radiometer Suite (VIIRS are currently onboard the Suomi National Polar-orbiting Partnership (Suomi NPP satellite and will continue to be carried on the same platform as future Joint Polar Satellite System (JPSS satellites for the next decade, it is desirable to develop a fast and accurate collocation scheme to collocate VIIRS products and measurements with CrIS for applications that rely on combining measurements from two sensors such as inter-calibration, geolocation assessment, and cloud detection. In this study, an accurate and fast collocation method to collocate VIIRS measurements within CrIS instantaneous field of view (IFOV directly based on line-of-sight (LOS pointing vectors is developed and discussed in detail. We demonstrate that this method is not only accurate and precise from a mathematical perspective, but also easy to implement computationally. More importantly, with optimization, this method is very fast and efficient and thus can meet operational requirements. Finally, this collocation method can be extended to a wide variety of sensors on different satellite platforms.

  1. Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 3: Project cost estimates

    Science.gov (United States)

    1990-01-01

    The laser atmospheric wind sounder (LAWS) cost modeling activities were initiated in phase 1 to establish the ground rules and cost model that would apply to both phase 1 and phase 2 cost analyses. The primary emphasis in phase 1 was development of a cost model for a LAWS instrument for the Japanese Polar Orbiting Platform (JPOP). However, the Space Station application was also addressed in this model, and elements were included, where necessary, to account for Space Station unique items. The cost model presented in the following sections defines the framework for all LAWS cost modeling. The model is consistent with currently available detail, and can be extended to account for greater detail as the project definition progresses.

  2. Examining Buoyancy Waves in the Martian Atmosphere with Mars Climate Sounder

    Science.gov (United States)

    Edmonds, Robert; Murphy, J.; Teal, D.

    2010-10-01

    Bouyancy ('gravity') waves can potentially play a significant role in the dynamics of the Martian atmosphere (Barnes, 1990). Small wave disturbances created at the surface (i.e. topographically) or at low altitudes (ex. convection) can propagate vertically under the appropriate thermodynamic conditions. To conserve energy, the amplitude of small waves can grow substantially in response to decreasing densities at higher altitudes. Gravity waves in the upper atmosphere have been analyzed from atmospheric densities derived from aerobarking Martian spacecraft (Creasey et al., 2006b & Fritts et al., 2006). Potentially large wave amplitudes aloft can result in wave saturation and wave breaking (Lindzen, 1981). The breaking waves deposit momentum, potentially altering the winds at that breaking level substantially. Creasey et al. (2006a) investigated the amplitudes of Martian atmospheric gravity waves by attempting to determine their manifested temperature perturbations as derived from Mars Global Surveyor (MGS) radio occultation measurements. Their results showed little correlation between topographic variance and gravitational wave energy. Motivated by this result, we are interested in how wave energies derived from Mars Climate Sounder (MCS) limb radiance measurements compare to the MGS Radio Science (RS) results. The continuous nature of the MCS measurements offer the opportunity to systematically investigate buoyancy wave characteristics diurnally, seasonally, and geographically, and to do so to a higher altitude (lower pressure) than the MGS RS profiles afforded. The MCS data used in this work is made publicly available through NASA's Planetary Data System's Atmospheres Node. This work is supported by NSF Grant ATM-0535811 (Univ. of Michigan), NMSU subcontract 3000615888 Barnes, J.R., 1990, JGR, 95, B2, 1401-1421. Creasey, J.E., et al., 2006, Geophys. Res. Lett., 33, L01803. Creasey, J.E., et al., 2006, Geophys. Res. Lett., 33, L22814. Fritts, D.C., et al., 2006

  3. An evaluation and comparison of vertical profile data from the VISSR Atmospheric Sounder (VAS)

    Science.gov (United States)

    Jedlovec, G. J.

    1985-01-01

    A statistical evaluation is used to compared vertical profiles of temperature and moisture derived from VISSR Atmospheric Sounder (VAS) with three different algorithms to that of corresponding rawinsonde measurements for a clear cold environment. To account for time and space discrepancies between the data sets, rawinsonde data were adjusted to be representative of the satellite sounding times. Both rawinsonde and satellite sounding data were objectively analyzed onto a mesoscale grid. These grid point values were compared at 50 mb pressure increments from the surface up to 100 mb. The data were analyzed for horizontal and vertical structure, representatives of derived parameters, and significant departure (improvement) from the apriori (first guess) information. Results indicate some rather strong temperature and moisture biases exist in the satellite soundings. Temperature biases of 1 to 4 C and dewpoint biases of 2 to 6 C generally occur in layers where strong inversions are present and vary with time as these atmospheric features evolve. The biases also changes as a function retrieval scheme suggesting limitations and restrictions on the applications of the various techniques. Standard temperature deviations range from 1 to 2 C for each retrieval scheme with maximum values around 800 and 400 mb. Derived parameters (precipitable water and thickness) suffer from similar biases, though to a somewhat lesser extent. Gradients of basic and derived parameters are generally weaker but have good horizontal structure where magnitudes of the parameters are relatively strong. Integrated thermal (temperature) and moisture (precipitable water) parameters show mixed results.

  4. Next generation global Earth atmospheric composition sounders for the decadal survey requirements and roadmaps Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There are two overall objectives: 1. Define the spatial resolutions and sensitivities required for the instruments; 2. Mature the technology for the limb sounder...

  5. Development and characterization of the superconducting integrated receiver channel of the TELIS atmospheric sounder

    International Nuclear Information System (INIS)

    The balloon-borne instrument TELIS (TErahertz and submillimetre LImb Sounder) is a three-channel superconducting heterodyne spectrometer for atmospheric research use. It detects spectral emission lines of stratospheric trace gases that have their rotational transitions at THz frequencies. One of the channels is based on the superconducting integrated receiver (SIR) technology. We demonstrate for the first time the capabilities of the SIR technology for heterodyne spectroscopy in general, and atmospheric limb sounding in particular. We also show that the application of SIR technology is not limited to laboratory environments, but that it is well suited for remote operation under harsh environmental conditions. Within a SIR the main components needed for a superconducting heterodyne receiver such as a superconductor-insulator-superconductor (SIS) mixer with a quasi-optical antenna, a flux-flow oscillator (FFO) as the local oscillator, and a harmonic mixer to phase lock the FFO are integrated on a single chip. Light weight and low power consumption combined with broadband operation and nearly quantum limited sensitivity make the SIR a perfect candidate for use in future airborne and space-borne missions. The noise temperature of the SIR was measured to be as low as 120 K, with an intermediate frequency band of 4-8 GHz in double-sideband operation. The spectral resolution is well below 1 MHz, confirmed by our measurements. Remote control of the SIR under flight conditions has been demonstrated in a successful balloon flight in Kiruna, Sweden. The sensor and instrument design are presented, as well as the preliminary science results from the first flight.

  6. Development and characterization of the superconducting integrated receiver channel of the TELIS atmospheric sounder

    Science.gov (United States)

    de Lange, Gert; Birk, Manfred; Boersma, Dick; Dercksen, Johannes; Dmitriev, Pavel; Ermakov, Andrey B.; Filippenko, Lyudmila V.; Golstein, Hans; Hoogeveen, Ruud W. M.; de Jong, Leo; Khudchenko, Andrey V.; Kinev, Nickolay V.; Kiselev, Oleg S.; van Kuik, Bart; de Lange, Arno; van Rantwijk, Joris; Selig, Avri M.; Sobolev, Alexander S.; Torgashin, Mikhail Yu; de Vries, Ed; Wagner, Georg; Yagoubov, Pavel A.; Koshelets, Valery P.

    2010-04-01

    The balloon-borne instrument TELIS (TErahertz and submillimetre LImb Sounder) is a three-channel superconducting heterodyne spectrometer for atmospheric research use. It detects spectral emission lines of stratospheric trace gases that have their rotational transitions at THz frequencies. One of the channels is based on the superconducting integrated receiver (SIR) technology. We demonstrate for the first time the capabilities of the SIR technology for heterodyne spectroscopy in general, and atmospheric limb sounding in particular. We also show that the application of SIR technology is not limited to laboratory environments, but that it is well suited for remote operation under harsh environmental conditions. Within a SIR the main components needed for a superconducting heterodyne receiver such as a superconductor-insulator-superconductor (SIS) mixer with a quasi-optical antenna, a flux-flow oscillator (FFO) as the local oscillator, and a harmonic mixer to phase lock the FFO are integrated on a single chip. Light weight and low power consumption combined with broadband operation and nearly quantum limited sensitivity make the SIR a perfect candidate for use in future airborne and space-borne missions. The noise temperature of the SIR was measured to be as low as 120 K, with an intermediate frequency band of 4-8 GHz in double-sideband operation. The spectral resolution is well below 1 MHz, confirmed by our measurements. Remote control of the SIR under flight conditions has been demonstrated in a successful balloon flight in Kiruna, Sweden. The sensor and instrument design are presented, as well as the preliminary science results from the first flight.

  7. High Vertically Resolved Atmospheric and Surface/Cloud Parameters Retrieved with Infrared Atmospheric Sounding Interferometer (IASI)

    Science.gov (United States)

    Zhou, Daniel K.; Liu, Xu; Larar, Allen M.; Smith, WIlliam L.; Taylor, Jonathan P.; Schluessel, Peter; Strow, L. Larrabee; Mango, Stephen A.

    2008-01-01

    The Joint Airborne IASI Validation Experiment (JAIVEx) was conducted during April 2007 mainly for validation of the IASI on the MetOp satellite. IASI possesses an ultra-spectral resolution of 0.25/cm and a spectral coverage from 645 to 2760/cm. Ultra-spectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. An advanced retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. This physical inversion scheme has been developed, dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders, to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A fast radiative transfer model, which applies to the cloud-free and/or clouded atmosphere, is used for atmospheric profile and cloud parameter retrieval. A one-dimensional (1-d) variational multi-variable inversion solution is used to improve an iterative background state defined by an eigenvector-regression-retrieval. The solution is iterated in order to account for non-linearity in the 1-d variational solution. It is shown that relatively accurate temperature and moisture retrievals are achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to cloud top level are obtained. For both optically thin and thick cloud situations, the cloud top height can be retrieved with relatively high accuracy (i.e., error Interferometer (NAST-I), dedicated dropsondes, radiosondes, and ground based Raman Lidar. The capabilities of satellite ultra-spectral sounder such as the IASI are investigated indicating a high vertical structure of atmosphere is retrieved.

  8. A novel retrieval of daytime atmospheric dust and volcanic ash heights through a synergy of AIRS infrared radiances and MODIS L2 optical depths

    OpenAIRE

    DeSouza-Machado, S.; Strow, L.; E. Maddy; O. Torres; Thomas, G.; Grainger, D; Robinson, A.

    2015-01-01

    We present a novel method to retrieve daytime atmospheric dust and ash plume heights using a synergy of infrared hyper-spectral radiances and retrieved visible optical depths. The method is developed using data from the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS), both of which are on NASA's Aqua platform, and lends itself to also a χ2 height derivation based on the smallest bias between observations and ...

  9. Role of the advanced IR sounder in land surface remote sensing

    Science.gov (United States)

    Knuteson, Robert O.

    2005-09-01

    A new era of Earth remote sensing began with the launch of the NASA EOS Aqua platform with the Atmospheric InfraRed Sounder (AIRS) in May 2002. The EOS AIRS instrument is the first in a series of high spectral resolution infrared spectrometers that will allow improved characterization of the global atmospheric temperature and water vapor structure. Follow-on operational sensors with similar sounding capability include the Cross-track InfraRed Sounder (CrIS) on the NPP/NPOESS satellites and the Infrared Advanced Sounding Interferometer (IASI) on the European METOP series. These so-called advanced infrared sounders will have a vital role to play in the remote sensing of land ecosystems. This paper describes how the use of Advanced IR Sounder data can be used to improve the accuracy of atmospheric corrections in the thermal IR and provide detailed information on the spectral dependence of the infrared land surface emissivity. Radiance observations from AIRS have been obtained over a large, uniform sandy desert region in the Libyan Desert suitable for evaluation of the 15-km footprints of the NASA AIRS advanced sounder. Analysis of this data indicates a spectral contrast of more than 30% between 12 mm and 9 mm in the surface infrared emissivity due to the presence of the mineral quartz with somewhat smaller contrast at 4 mm. Results of a method for separation of infrared surface emissivity and effective surface skin temperature are presented also.

  10. Enhancements in lower stratospheric CH3CN observed by the upper atmosphere research Sattellite Microwave Limb Sounder following boreal forest fires

    Science.gov (United States)

    Livesey, N. J.; Fromm, M. D.; Waters, J. W.; Manney, G. L.; Santee, M. L.; Read, W. G.

    2004-01-01

    On 25 August 1992, the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite observed a significant enhancement in the abundance of lower stratospheric methyl cyanide (CH3CN) at 100??hPa (16??km altitude) in a small region off the east coast of Florida.

  11. Definition and preliminary design of the Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 3: Program cost estimates

    Science.gov (United States)

    1990-01-01

    Cost estimates for phase C/D of the laser atmospheric wind sounder (LAWS) program are presented. This information provides a framework for cost, budget, and program planning estimates for LAWS. Volume 3 is divided into three sections. Section 1 details the approach taken to produce the cost figures, including the assumptions regarding the schedule for phase C/D and the methodology and rationale for costing the various work breakdown structure (WBS) elements. Section 2 shows a breakdown of the cost by WBS element, with the cost divided in non-recurring and recurring expenditures. Note that throughout this volume the cost is given in 1990 dollars, with bottom line totals also expressed in 1988 dollars (1 dollar(88) = 0.93 1 dollar(90)). Section 3 shows a breakdown of the cost by year. The WBS and WBS dictionary are included as an attachment to this report.

  12. Definition and preliminary design of the Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 3: Program cost estimates

    Science.gov (United States)

    1990-05-01

    Cost estimates for phase C/D of the laser atmospheric wind sounder (LAWS) program are presented. This information provides a framework for cost, budget, and program planning estimates for LAWS. Volume 3 is divided into three sections. Section 1 details the approach taken to produce the cost figures, including the assumptions regarding the schedule for phase C/D and the methodology and rationale for costing the various work breakdown structure (WBS) elements. Section 2 shows a breakdown of the cost by WBS element, with the cost divided in non-recurring and recurring expenditures. Note that throughout this volume the cost is given in 1990 dollars, with bottom line totals also expressed in 1988 dollars (1 dollar(88) = 0.93 1 dollar(90)). Section 3 shows a breakdown of the cost by year. The WBS and WBS dictionary are included as an attachment to this report.

  13. Observation of atmospheric composition by Superconducting SubMillimeter-wave Limb Emission Sounder (SMILES) onbord International Space Station

    Science.gov (United States)

    Kasai, Y.; Philippe, B.; Mendrok, J.; Ochiai, S.; Urban, J.; Manabe, T.; Kikuchi, K.; Nishibori, T.; Sano, T.; Moller, J.; Murtagh, D. P.

    2009-12-01

    The Superconducting SubMillimeter-wave Limb Emission The Superconducting SubMillimeter-wave Limb Emission Sounder (SMILES) is the first application of superconductor--insulator--superconductor (SIS) heterodyne detector technology to the investigation of the Earth atmosphere from space. SMILES was designed to be onboard the Japanese Experiment Module (JEM) on the International Space Station (ISS), and is scheduled to be launched on 11 September 2009 by the H-II Transfer Vehicle (HTV). SMILES is a collaboration project of the National Institute of Information and Communications Technology (NICT) and the Japan Aerospace Exploration Agency (JAXA). The performance of this state-of-the-art SIS receiver, with an estimated single side band (SSB) receiver noise temperature of 500 K at 625--650 GHz, provides a large improvement in sensitivity compared to the conventional submillimeter-wave Schottky-diode receivers used by the Sub-Millimetre Radiometer (SMR) onboard the Odin satellite (3000K, single side band, 485--580 GHz, cooled) and the Millimeter-wave Limb Sounder (MLS) onboard Aura (12000K, double side band at 625--650 GHz, uncooled). Since the integration time reduces with the square of the system noise temperature, this performance is roughly equivalent to reducing by a factor of up to 5-10 the integration time needed to reaching the same noise equivalent brightness temperatures. SMILES measurements thus have the potential to provide meaningful information on the global distribution of short-lived radical species, such as ozone, HCl, ClO, HO2, HOCl, CH3CN, BrO, H2O and ice cloud. NICT is operating the L2 research/L3 operational processing chain. In this paper, we introduce the status of SMILES data and its observation performance.

  14. RETRIEVING ATMOSPHERIC SOUNDING PROFILES AROUND TYPHOON YUNNA USING INFRARED HYPERSPECTRAL MEASUREMENTS AIRS

    Institute of Scientific and Technical Information of China (English)

    HUANG Bing; LIU Jian-wen; BAI Jie; LI Yao-dong; GAO Shou-ting

    2010-01-01

    In this study, we derived atmospheric profiles of temperature, moisture, and ozone, along with surface emissivity, skin temperature, and surface pressure, from infrared-sounder radiances under clear sky (cloudless) condition. Clouds were detected objectively using the Atmospheric Infrared Sounder under a relatively low spatial resolution and cloud-mask information from the Moderate Resolution Imaging Spectroradiometer under a high horizontal resolution; this detection was conducted using space matching.Newton's nonlinear physical iterative solution technique is applied to the radiative transfer equation (RTE) to retrieve temperature profiles, relative humidity profiles, and surface variables simultaneously. This technique is carried out by using the results of an eigenvector regression retrieval as the background profile and using corresponding iterative forms for the weighting functions of temperature and water-vapor mixing ratio. The iterative forms are obtained by applying the variational principle to the RTE. We also compared the retrievals obtained with different types of observations. The results show that the retrieved atmospheric sounding profile has great superiority over other observations by accuracy and resolution. Retrieved profiles can be used to improve the initial conditions of numerical models and used in areas where conventional observations are sparse, such as plateaus, deserts, and seas.

  15. Retrieval of tropospheric CO column from hyperspectral infrared sounders – application to four years of Aqua/AIRS and MetOp-A/IASI

    Directory of Open Access Journals (Sweden)

    L. Crépeau

    2012-10-01

    Full Text Available Four years of tropospheric integrated content of CO were retrieved from infrared hyperspectral observations of AIRS onboard Aqua and IASI onboard MetOp-A, for the period July 2007–June 2011. The retrieval method is based on a double differential approach that relies on the difference between brightness temperatures observed by the sounder and BT simulated by the Automatised Atmospheric Absorption Atlas (4A radiative transfer model on colocated ECMWF reanalyses, for several couples of channels located in the 4.67 μm CO band. AIRS and IASI give access to similar integrated contents of CO with a maximum sensitivity near 450 hPa and a half-height width of the weighting function between 200 and 750 hPa depending on the thermal contrast (i.e., the difference between the surface temperature and the temperature of the first pressure level. However, differences in their spectral and radiometric characteristics yield differences in the retrieval characteristics with AIRS selected couples of channels being more sensitive to surface characteristics. Moreover, IASI covers the whole CO absorption band, with a 3 times better spectral resolution, giving access to channels presenting a 3 times higher signal to noise ratio. This results in a better precision and lower standard deviation of the IASI retrievals. Conservatively, comparisons with CARIBIC aircraft measurements yield an averaged relative difference of 3.4% for IASI and 4.9% for AIRS. On average, AIRS and IASI retrievals are in very good agreement, showing the same seasonality, seasonal amplitudes, interannual variability and spatial distribution. The analysis of the monthly evolution of CO particularly highlights the expected strong influence of biomass burning on the evolution of CO in several tropical regions. In particular, a sharp increase in CO in 2010 in the southern tropics, especially over South America and South Africa, is observed, and is shown to be related to El Niño and to the Atlantic

  16. Definition Of An Uncooled Submillimeter/Terahertz LIMB Sounder For Measuring Middle Atmospheric Winds

    Science.gov (United States)

    Baron, P.; Murtagh, D. P.; Urban, J.; Sagawa, H.; Eriksson, P.; Ochiai, S.

    2013-12-01

    Simulations from 100 GHz to 3 THz for assessing the potential of spaceborne microwave spectrometer for observing winds at the atmospheric limb have been performed. The line-of-sight wind can be derived from 25 km to more than 90 km with a radiometer of moderate sensitivity. For example, winds can be retrieved from 20 km to more than 90 km from observations using a single side- band radiometer with a system temperature of 1440 K at 600 GHz. Such radiometer can be realized with a Schottky diode cooled down to 100 K. A well established and reliable technology can be used for the cooler with low power, mass and costs, and without compromising the mission life-time. In the sub-millimetre and terahertz ranges, high quality retrievals are obtained from 40 km to 65 km by choosing favourable spectral ranges contain- ing a cluster of strong O3 lines. The vertical resolution is better than 5 km and the precision is 2-3 ms-1. Be- tween 25 km and 35 km, the best retrievals are obtained at 233 GHz and 352 GHz with a vertical resolution better than 8 km and a precision better than 15 ms-1. The spectral bands are similar to and compatible with the ones used for observing stratospheric trace-gases. Given the lack of past and future wind measurements above 30 km, winds should be regarded as one of the possible products for middle atmospheric trace-gases measurement mission and should be taken into account in the definition of the mission.

  17. Simultaneous middle and upper atmosphere radar and ionospheric sounder observations of midlatitude E region irregularities and sporadic E layer

    Science.gov (United States)

    Ogawa, T.; Takahashi, O.; Otsuka, Y.; Nozaki, K.; Yamamoto, M.; Kita, K.

    2002-10-01

    We made middle and upper atmosphere (MU) radar observations of midlatitude E region field-aligned irregularities (FAIs) in the summer of 1999 and 2000. Sporadic E (Es) layer was monitored with a routine ionosonde, and its altitude was measured with an FM-CW sounder (FCS). In this paper we draw attention to two findings. First, we show that quasiperiodic (QP) radar echoes appearing before 0200 LT are more enhanced with increasing foEs - fbEs, which means that the FAI generation is closely related to localized density gradients within Es, and extend from 100 to 130 km in altitude, while Es altitudes determined from the FCS soundings are between 100 and 110 km. The latter fact suggests that existing models for the QP echo generation, which require a deep modulation of Es altitude, are not applicable to our observational results. We propose a new working model for generating QP echoes in which polarization electric fields originated from high-density plasma clouds within Es are mapped upward along the geomagnetic field to produce relatively weak irregularities above the Es layer. Second, we show new findings obtained from the current observations, namely, two types of QP echoes that occur below 100 km in the morning: one is the morning QP (MQP) echoes with periods of 4-8 min, and the other is the QP echoes with periods of ˜1 min. The latter type can be categorized as low-altitude QP echoes that were found from previous nighttime MU radar observations. Until now the MU radar QP echoes have been believed to occur above 100 km for the period from sunset to midnight. Although we do not know the generation mechanisms of the low-altitude MQP echoes, we suppose that these echoes might be caused by a weak Es that exists below 100 km.

  18. A single-scattering approximation for infrared radiative transfer in limb geometry in the Martian atmosphere

    International Nuclear Information System (INIS)

    We present a single-scattering approximation for infrared radiative transfer in limb geometry in the Martian atmosphere. It is based on the assumption that the upwelling internal radiation field is dominated by a surface with a uniform brightness temperature. It allows the calculation of the scattering source function for individual aerosol types, mixtures of aerosol types, and mixtures of gas and aerosol. The approximation can be applied in a Curtis-Godson radiative transfer code and is used for operational retrievals from Mars Climate Sounder measurements. Radiance comparisons with a multiple scattering model show good agreement in the mid- and far-infrared although the approximate model tends to underestimate the radiances in realistic conditions of the Martian atmosphere. Relative radiance differences are found to be about 2% in the lowermost atmosphere, increasing to ∼10% in the middle atmosphere of Mars. The increasing differences with altitude are mostly due to the increasing contribution to limb radiance of scattering relative to emission at the colder, higher atmospheric levels. This effect becomes smaller toward longer wavelengths at typical Martian temperatures. The relative radiance differences are expected to produce systematic errors of similar magnitude in retrieved opacity profiles.

  19. Digitization of acoustic sounder data

    International Nuclear Information System (INIS)

    A method of archiving acoustic sounder data in a format compatible with a computer is used development. The collected data will be used to compile a climatology of the atmospheric surface boundary layer to predict the transport and diffusion of atmospheric pollutants

  20. Infrared spectroscopic measurements on planetary atmospheric gases

    International Nuclear Information System (INIS)

    Infrared spectroscopic measurements were performed on trace gas molecules known to be infrared-active in the atmospheres of Earth and the Outer Planets. The measurements were performed at low temperatures relevant to the planetary atmospheres employing the high spectral resolution attainable with a tunable diode laser spectrometer. Accurate data on the intensities, N(2-), O(2-), and air-broadened half-widths of lines in the nu(sub 1)-fundamental band (7.78 microns) of 14-N2O-16 were obtained at several temperatures between 185 and 296 K. These data are needed in remote sensing, ozone depletion, and climate modeling studies of the terrestrial atmosphere. The pressure-induced shifts of some 14-N2O-16 lines were also measured. Intensity data in the 10(sup 0)0-01(sup 1)0 band (13.87 microns) of 12-C16-O2 at 295 K which are useful in studies of the thermal structure of the Earth's atmosphere were measured. They differ significantly from previously published and cataloged data. Measurements of the absolute intensities and the H2-broadened half-widths of several spectral lines in the nu(sub 3) band of GeH4, which was detected in the atmospheres of the Outer Planets, were performed at low temperatures between 94 and 300 K. The combined intensity of the nu(sub 3) bands of all of the five isotopic species of GeH4 as well as that of the Q-branches alone were measured independently at 294 using the Wilson-Wells-Penner-Weber Technique. Absolute intensities, collision-broadened half-widths, and pressure-induced shifts of several lines in the nu(sub 4)-fundamental bands of 12-CH4 and 13-CH4 around 7.70 microns, the nu(sub 2)-fundamantal band of 12-CH3D at 4.55 microns, the nu(sub 3)-fundamental band of 12-CH3D at 7.76 microns, the nu(sub 6)-fundamental band of 12-CH3D at 8.61 microns, and the CO fundamental at 4.67 microns, all of which appear in the spectra of the Outer Planets, were measured at low temperatures

  1. Assessments of F16 Special Sensor Microwave Imager and Sounder Antenna Temperatures at Lower Atmospheric Sounding Channels

    OpenAIRE

    Fuzhong Weng; Banghua Yan

    2009-01-01

    The main reflector of the Special Sensor Microwave Imager/Sounder (SSMIS) aboard the Defense Meteorological Satellite Program (DMSP) F-16 satellite emits variable radiation, and the SSMIS warm calibration load is intruded by direct and indirect solar radiation. These contamination sources produce antenna brightness temperature anomalies of around 2 K at SSMIS sounding channels which are obviously inappropriate for assimilation into numerical weather prediction models and remote sensing retrie...

  2. Impact of Measurement System Characteristics on Advanced Sounder Information Content

    Science.gov (United States)

    Larar, Allen M.; Liu, Xu; Zhou, Daniel K.

    2011-01-01

    Advanced satellite sensors are tasked with improving global observations of the Earth's atmosphere, clouds, and surface to enable enhancements in weather prediction, climate monitoring capability, and environmental change detection. Achieving such an improvement in geophysical information inferred from these observations requires optimal usage of data from current systems as well as instrument system enhancements for future sensors. This presentation addresses results of tradeoff studies evaluating the impact of spectral resolution, spectral coverage, instrument noise, and a priori knowledge on remote sensing system information content, with a specific emphasis on thermodynamic state and trace species information obtainable from advanced atmospheric sounders. Particular attention will be devoted toward information achievable from the Atmospheric InfraRed Sounder (AIRS) on the NASA EOS Aqua satellite in orbit since 2002, the Infrared Atmospheric Sounding Interferometer (IASI) aboard MetOp-A since 2006, and the Cross-track Infrared Sounder (CrIS) instrument to fly aboard the NPP and JPSS series of satellites expected to begin in late 2011. While all of these systems cover nearly the same infrared spectral extent, they have very different number of channels, instrument line shapes, coverage continuity, and instrument noise. AIRS is a grating spectrometer having 2378 discrete spectral channels ranging from about 0.4 to 2.2/cm resolution; IASI is a Michelson interferometer with 8461 uniformly-spaced spectral channels of 0.5/cm (apodized) resolution; and CrIS is a Michelson interferometer having 1305 spectral channels of 0.625, 1.250, and 2.50/cm (unapodized) spectral resolution, respectively, over its three continuous but non-overlapping bands. Results of tradeoff studies showing information content sensitivity to assumed measurement system characteristics will be presented.

  3. Infrared remote sensing of atmospheric aerosols; Apports du sondage infrarouge a l'etude des aerosols atmospheriques

    Energy Technology Data Exchange (ETDEWEB)

    Pierangelo, C.

    2005-09-15

    The 2001 report from the Intergovernmental Panel on Climate Change emphasized the very low level of understanding of atmospheric aerosol effects on climate. These particles originate either from natural sources (dust, volcanic aerosols...) or from anthropogenic sources (sulfates, soot...). They are one of the main sources of uncertainty on climate change, partly because they show a very high spatio-temporal variability. Observation from space, being global and quasi-continuous, is therefore a first importance tool for aerosol studies. Remote sensing in the visible domain has been widely used to obtain a better characterization of these particles and their effect on solar radiation. On the opposite, remote sensing of aerosols in the infrared domain still remains marginal. Yet, not only the knowledge of the effect of aerosols on terrestrial radiation is needed for the evaluation of their total radiative forcing, but also infrared remote sensing provides a way to retrieve other aerosol characteristics (observations are possible at night and day, over land and sea). In this PhD dissertation, we show that aerosol optical depth, altitude and size can be retrieved from infrared sounder observations. We first study the sensitivity of aerosol optical properties to their micro-physical properties, we then develop a radiative transfer code for scattering medium adapted to the very high spectral resolution of the new generation sounder NASA-Aqua/AIRS, and we finally focus on the inverse problem. The applications shown here deal with Pinatubo stratospheric volcanic aerosol, observed with NOAA/HIRS, and with the building of an 8 year climatology of dust over sea and land from this sounder. Finally, from AIRS observations, we retrieve the optical depth at 10 {mu}m, the average altitude and the coarse mode effective radius of mineral dust over sea. (author)

  4. Assessment of error propagation in ultraspectral sounder data via JPEG2000 compression and turbo coding

    Science.gov (United States)

    Olsen, Donald P.; Wang, Charles C.; Sklar, Dean; Huang, Bormin; Ahuja, Alok

    2005-08-01

    Research has been undertaken to examine the robustness of JPEG2000 when corrupted by transmission bit errors in a satellite data stream. Contemporary and future ultraspectral sounders such as Atmospheric Infrared Sounder (AIRS), Cross-track Infrared Sounder (CrIS), Infrared Atmospheric Sounding Interferometer (IASI), Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS), and Hyperspectral Environmental Suite (HES) generate a large volume of three-dimensional data. Hence, compression of ultraspectral sounder data will facilitate data transmission and archiving. There is a need for lossless or near-lossless compression of ultraspectral sounder data to avoid potential retrieval degradation of geophysical parameters due to lossy compression. This paper investigates the simulated error propagation in AIRS ultraspectral sounder data with advanced source and channel coding in a satellite data stream. The source coding is done via JPEG2000, the latest International Organization for Standardization (ISO)/International Telecommunication Union (ITU) standard for image compression. After JPEG2000 compression the AIRS ultraspectral sounder data is then error correction encoded using a rate 0.954 turbo product code (TPC) for channel error control. Experimental results of error patterns on both channel and source decoding are presented. The error propagation effects are curbed via the block-based protection mechanism in the JPEG2000 codec as well as memory characteristics of the forward error correction (FEC) scheme to contain decoding errors within received blocks. A single nonheader bit error in a source code block tends to contaminate the bits until the end of the source code block before the inverse discrete wavelet transform (IDWT), and those erroneous bits propagate even further after the IDWT. Furthermore, a single header bit error may result in the corruption of almost the entire decompressed granule. JPEG2000 appears vulnerable to bit errors in a noisy channel of

  5. GEO/SAMS - The Geostationary Synthetic Aperture Microwave Sounder

    Science.gov (United States)

    Lambrigtsen, Bjorn H.

    2008-01-01

    The National Oceanic and Atmospheric Administration (NOAA) has for many years operated two weather satellite systems, the Polar-orbiting Operational Environmental Satellite system (POES), using low-earth orbiting (LEO) satellites, and the Geostationary Operational Environmental Satellite system (GOES), using geostationary earth orbiting (GEO) satellites. (Similar systems are also operated by other nations.) The POES satellites have been equipped with both infrared (IR) and microwave (MW) atmospheric sounders, which makes it possible to determine the vertical distribution of temperature and humidity in the troposphere even under cloudy conditions. Such satellite observations have had a significant impact on weather forecasting accuracy, especially in regions where in situ observations are sparse. In contrast, the GOES satellites have only been equipped with IR sounders, since it has not been feasible to build a large enough antenna to achieve sufficient spatial resolution for a MW sounder in GEO. As a result, GOES soundings can only be obtained in cloud free areas and in the less important upper atmosphere, above the cloud tops. This has hindered the effective use of GOES data in numerical weather prediction. Full sounding capabilities with the GOES system is highly desirable because of the advantageous spatial and temporal coverage that is possible from GEO. While POES satellites provide coverage in relatively narrow swaths, and with a revisit time of 12-24 hours or more, GOES satellites can provide continuous hemispheric coverage, making it possible to monitor highly dynamic phenomena such as hurricanes.

  6. Dust aerosol optical depth and altitude retrieved from 7 years of infrared sounders observations (AIRS, IASI) and comparison with other aerosol datasets (MODIS, CALIOP, PARASOL)

    Science.gov (United States)

    Peyridieu, Sophie; Chédin, Alain; Tanré, Didier; Capelle, Virginie; Pierangelo, Clémence; Lamquin, Nicolas; Armante, Raymond

    2010-05-01

    Remote sensing of aerosol properties in the visible domain has been widely used for a better characterization of these particles and of their effect on solar radiation. On the opposite, remote sensing of aerosols in the thermal infrared domain still remains marginal. However, knowledge of the effect of aerosols on terrestrial radiation is needed for the evaluation of their total radiative forcing. A key point of infrared remote sensing is its ability to retrieve aerosol optical depth as well as mean dust layer altitude, a variable required for measuring their impact on climate. Moreover, observations are possible night and day, over ocean and over land. Our algorithm is specifically designed to retrieve simultaneously coarse mode dust aerosol 10 µm optical depth (AOD) and mean layer altitude from high spectral resolution infrared sounders observations. Thanks to IASI higher spectral resolution, the selection of finer channels for aerosol detection allows an even more accurate determination of aerosol properties. In this context, results obtained from 7 years (2003-2010) of AIRS/Aqua and more than 2 years (2007-2010) of IASI/Metop observations have been compared to other aerosol sensors. Compared to MODIS/Aqua optical depth product, 10 µm dust optical depth shows a very good agreement, particularly for tropical Atlantic regions downwind of the Sahara during the dust season. Comparisons with PARASOL non-spherical coarse mode product allows explaining small differences observed far from the sources. Time series of the mean aerosol layer altitude are compared to the CALIOP Level-2 products starting June 2006. For regions located downwind of the Sahara, the comparison again shows a good agreement with a mean standard deviation between the two products of about 400 m over the period processed, demonstrating that our algorithm effectively allows retrieving accurate mean dust layer altitude. A 7-year global climatology of the aerosol 10 µm dust optical depth and of the

  7. Measurements of hydrogen cyanide (HCN and acetylene (C2H2 from the Infrared Atmospheric Sounding Interferometer (IASI

    Directory of Open Access Journals (Sweden)

    V. Duflot

    2013-04-01

    Full Text Available Hydrogen cyanide (HCN and acetylene (C2H2 are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm−1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E and Jungfraujoch (46° N, 8° E in 2009–2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI. A first order comparison with local ground-based Fourier transform infraRed (FTIR measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values.

  8. Measurements of hydrogen cyanide (HCN and acetylene (C2H2 from the Infrared Atmospheric Sounding Interferometer (IASI

    Directory of Open Access Journals (Sweden)

    C. Clerbaux

    2012-10-01

    Full Text Available Hydrogen cyanide (HCN and acetylene (C2H2 are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q-branch near 720 cm−1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO2 line mixing we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S; 55° E and Jungfraujoch (46° N; 8° E in 2009–2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI. These are compared with local ground-based Fourier Transform InfraRed (FTIR measurements and we demonstrate that the seasonality is well captured, except for HCN at Jungfraujoch. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values.

  9. Neptune's Atmospheric Composition from AKARI Infrared Spectroscopy

    CERN Document Server

    Fletcher, Leigh N; Burgdorf, Martin; Orton, Glenn; Encrenaz, Therese; 10.1051/0004-6361/200913358

    2010-01-01

    Aims: Disk-averaged infrared spectra of Neptune between 1.8 and 13 $\\mu$m, obtained by the AKARI Infrared Camera (IRC) in May 2007, have been analysed to (a) determine the globally-averaged stratospheric temperature structure; (b) derive the abundances of stratospheric hydrocarbons; and (c) detect fluorescent emission from CO at 4.7 $\\mu$m. Methods: Mid-infrared spectra were modelled using a line-by-line radiative transfer code to determine the temperature structure between 1-1000 $\\mu$bar and the abundances of CH$_4$, CH$_3$D and higher-order hydrocarbons. A full non-LTE radiative model was then used to determine the best fitting CO profile to reproduce the fluorescent emission observed at 4.7 $\\mu$m in the NG channel (with a spectral resolution of 135). Results: The globally-averaged stratospheric temperature structure is quasi-isothermal between 1-1000 $\\mu$bar, which suggests little variation in global stratospheric conditions since studies by the Infrared Space Observatory a decade earlier. The derived C...

  10. Retrieval of tropospheric CO column from hyperspectral infrared sounders – application to four years of Aqua/AIRS and MetOp-A/IASI

    Directory of Open Access Journals (Sweden)

    L. Crépeau

    2012-05-01

    Full Text Available Four years of tropospheric integrated content of CO are retrieved from infrared hyperspectral observations of AIRS onboard Aqua and IASI onboard MetOp-A, for the period July 2007–June 2011. The retrieval method is based on a double differential approach that relies on the difference between brightness temperatures (BT observed by the sounder and BT simulated by the 4A radiative transfer model on collocated ECMWF reanalyses, for several couples of channels located in the 4.7 μm CO band. AIRS and IASI give access to similar integrated contents of CO with a maximum sensitivity near 450 hPa and half a maximum between 200 and 750 hPa depending on the thermal contrast (i.e. the difference between the surface temperature and the temperature of the first pressure level. However, differences in their spectral and radiometric characteristics yield differences in the retrieval characteristics with AIRS selected couples of channels being more sensitive to surface characteristics. Moreover, IASI covers the whole CO absorption band, with a 3 times greater spectral resolution, giving access to channels presenting a 3 times higher signal to noise ratio. This results in a better precision and lower standard deviation of the IASI retrievals. Conservatively, comparisons with CARIBIC aircraft measurements yield a relative difference of 3.42% for IASI and 4.92% for AIRS. On average, AIRS and IASI retrievals are in very good agreement, showing the same seasonality, seasonal amplitudes, interannual variability and spatial distribution. The analysis of the monthly evolution of CO particularly highlights the strong influence of biomass burning on the evolution of CO in several tropical regions. In particular, a sharp increase in CO in 2010 in the southern tropics, especially over South America and South Africa, is observed, and is shown to be related to El Niño and to the Atlantic Multidecadal Oscillation.

  11. Airborne laser systems for atmospheric sounding in the near infrared

    Science.gov (United States)

    Sabatini, Roberto; Richardson, Mark A.; Jia, Huamin; Zammit-Mangion, David

    2012-06-01

    This paper presents new techniques for atmospheric sounding using Near Infrared (NIR) laser sources, direct detection electro-optics and passive infrared imaging systems. These techniques allow a direct determination of atmospheric extinction and, through the adoption of suitable inversion algorithms, the indirect measurement of some important natural and man-made atmospheric constituents, including Carbon Dioxide (CO2). The proposed techniques are suitable for remote sensing missions performed by using aircraft, satellites, Unmanned Aerial Vehicles (UAV), parachute/gliding vehicles, Roving Surface Vehicles (RSV), or Permanent Surface Installations (PSI). The various techniques proposed offer relative advantages in different scenarios. All are based on measurements of the laser energy/power incident on target surfaces of known geometric and reflective characteristics, by means of infrared detectors and/or infrared cameras calibrated for radiance. Experimental results are presented relative to ground and flight trials performed with laser systems operating in the near infrared (NIR) at λ = 1064 nm and λ = 1550 nm. This includes ground tests performed with 10 Hz and 20 KHz PRF NIR laser systems in a variety of atmospheric conditions, and flight trials performed with a 10 Hz airborne NIR laser system installed on a TORNADO aircraft, flying up to altitudes of 22,000 ft above ground level. Future activities are planned to validate the atmospheric retrieval algorithms developed for CO2 column density measurements, with emphasis on aircraft related emissions at airports and other high air-traffic density environments.

  12. Multiorder etalon sounder (MOES) development and test for balloon experiment

    Science.gov (United States)

    Hays, Paul B.; Wnag, Jinxue; Wu, Jian

    1993-01-01

    The Fabry-Perot interferometer (FPI), with its high throughput and high spectral resolution has been used in the remote-sensing measurements of the earth's atmospheric composition, winds, and temperatures. The most recent satellite instruments include the Fabry-Perot interferometer flown on the Dynamics Explorer-2 (DE-2), the High Resolution Doppler Imager (HRDI), and the Cryogenic Limb Array Etalon Spectrometer (CLAES) flown on the Upper Atmosphere Research Satellite (UARS). These instruments measure the Doppler line profiles of the emission and absorption of certain atmospheric species (such as atomic oxygen) in the visible and infrared spectral region. The successful space flight of DE-FPI, HRDI, and CLAES on UARS demonstrated the extremely high spectral resolution and ruggedness of the etalon system for the remote sensing of earth and planetary atmospheres. Recently, an innovative FPI focal plane detection technique called the Circle-to-Line Interferometer Optical (CLIO) system was invented at the Space Physics Research Laboratory. The CLIO simplifies the FPI focal plane detection process by converting the circular rings or fringes into a linear pattern similar to that produced by a conventional spectrometer, while retaining the throughput advantage of the etalon interferometer. The combination of FPI and CLIO allows the development of more sensitive Fabry-Perot interferometers in the infrared for the remote sensing of the lower atmospheres of Earth and possibly other planets. The Multiorder Etalon Sounder (MOES), a combination of the rugged etalon and the CLIO, compares very favorably to other space-borne optical instruments in terms of performance versus complexity. The new instrument is expected to be rugged, compact, and very suitable for an operational temperature and moisture sounder. With this technique, the contamination of radiance measurements by emissions of other gases is also minimized. At the Space Physics Research Laboratory (SPRL), the MOES

  13. Special Sensor Microwave Imager/Sounder (SSMIS) Temperature Data Record (TDR) in netCDF

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Special Sensor Microwave Imager/Sounder (SSMIS) is a series of passive microwave conically scanning imagers and sounders onboard the DMSP satellites beginning...

  14. Special Sensor Microwave Imager/Sounder (SSMIS) Sensor Data Record (SDR) in netCDF

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Special Sensor Microwave Imager/Sounder (SSMIS) is a series of passive microwave conically scanning imagers and sounders onboard the DMSP satellites beginning...

  15. Cloud and Thermodynamic Parameters Retrieved from Satellite Ultraspectral Infrared Measurements

    Science.gov (United States)

    Zhou, Daniel K.; Smith, William L.; Larar, Allen M.; Liu, Xu; Taylor, Jonathan P.; Schluessel, Peter; Strow, L. Larrabee; Mango, Stephen A.

    2008-01-01

    Atmospheric-thermodynamic parameters and surface properties are basic meteorological parameters for weather forecasting. A physical geophysical parameter retrieval scheme dealing with cloudy and cloud-free radiance observed with satellite ultraspectral infrared sounders has been developed and applied to the Infrared Atmospheric Sounding Interferometer (IASI) and the Atmospheric InfraRed Sounder (AIRS). The retrieved parameters presented herein are from radiance data gathered during the Joint Airborne IASI Validation Experiment (JAIVEx). JAIVEx provided intensive aircraft observations obtained from airborne Fourier Transform Spectrometer (FTS) systems, in-situ measurements, and dedicated dropsonde and radiosonde measurements for the validation of the IASI products. Here, IASI atmospheric profile retrievals are compared with those obtained from dedicated dropsondes, radiosondes, and the airborne FTS system. The IASI examples presented here demonstrate the ability to retrieve fine-scale horizontal features with high vertical resolution from satellite ultraspectral sounder radiance spectra.

  16. Mid-infrared laser filaments in the atmosphere

    CERN Document Server

    Mitrofanov, A V; Sidorov-Biryukov, D A; Pugžlys, A; Stepanov, E A; Andriukaitis, G; Flöry, T; Ališauskas, S; Fedotov, A B; Baltuška, A; Zheltikov, A M

    2014-01-01

    Filamentation of ultrashort laser pulses in the atmosphere offers unique opportunities for long-range transmission of high-power laser radiation and standoff detection. With the critical power of self-focusing scaling as the laser wavelength squared, the quest for longer-wavelength drivers, which would radically increase the peak power and, hence, the laser energy in a single filament, has been ongoing over two decades, during which time the available laser sources limited filamentation experiments in the atmosphere to the near-infrared and visible ranges. Here, we demonstrate filamentation of ultrashort mid-infrared pulses in the atmosphere for the first time. We show that, with the spectrum of a femtosecond laser driver centered at 3.9 um, right at the edge of the atmospheric transmission window, radiation energies above 20 mJ and peak powers in excess of 200 GW can be transmitted through the atmosphere in a single filament. Our studies reveal unique properties of mid-infrared filaments, where the generatio...

  17. In-flight control and communication architecture of the GLORIA imaging limb sounder on atmospheric research aircraft

    Science.gov (United States)

    Kretschmer, E.; Bachner, M.; Blank, J.; Dapp, R.; Ebersoldt, A.; Friedl-Vallon, F.; Guggenmoser, T.; Gulde, T.; Hartmann, V.; Lutz, R.; Maucher, G.; Neubert, T.; Oelhaf, H.; Preusse, P.; Schardt, G.; Schmitt, C.; Schönfeld, A.; Tan, V.

    2015-06-01

    The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA), a Fourier-transform-spectrometer-based limb spectral imager, operates on high-altitude research aircraft to study the transit region between the troposphere and the stratosphere. It is one of the most sophisticated systems to be flown on research aircraft in Europe, requiring constant monitoring and human intervention in addition to an automation system. To ensure proper functionality and interoperability on multiple platforms, a flexible control and communication system was laid out. The architectures of the communication system as well as the protocols used are reviewed. The integration of this architecture in the automation process as well as the scientific campaign flight application context are discussed.

  18. In-flight control and communication architecture of the GLORIA imaging limb-sounder on atmospheric research aircraft

    Directory of Open Access Journals (Sweden)

    E. Kretschmer

    2015-02-01

    Full Text Available The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA, a Fourier transform spectrometer based limb spectral imager, operates on high-altitude research aircraft to study the transit region between the troposphere and the stratosphere. It is one of the most sophisticated systems to be flown on research aircraft in Europe, requiring constant monitoring and human intervention in addition to an automation system. To ensure proper functionality and interoperability on multiple platforms, a flexible control and communication system was laid out. The architectures of the communication system as well as the protocols used are reviewed. The integration of this architecture in the automation process as well as the scientific campaign flight application context are discussed.

  19. Tomographic reconstruction of atmospheric volumes from infrared limb-imager measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ungermann, Joern

    2011-08-12

    State-of-the art nadir and limb-sounders, but also in situ measurements, do not offer the capability to highly resolve the atmosphere in all three dimensions. This leaves an observational gap with respect to small-scale structures that arise frequently in the atmosphere and that still lack a quantitative understanding. For instance, filaments and tropopause folds in the upper troposphere and lower stratosphere (UTLS) are crucial for its composition and variability. One way to achieve a highly resolved three-dimensional (3-D) picture of the atmosphere is the tomographic evaluation of limb-imager measurements. This thesis presents a methodology for the tomographic reconstruction of atmospheric constituents. To be able to deal with the large increase of observations and unknowns compared to conventional retrievals, great care is taken to reduce memory consumption and processing time. This method is used to evaluate the performance of two upcoming infrared limb-imager instruments and to prepare their missions. The first examined instrument is the infrared limb-imager on board of PREMIER (Process Exploration through Measurements of Infrared and millimetrewave Emitted Radiation), one of three remaining candidates for ESA's 7th Earth Explorer mission. Scientific goals of PREMIER are, among others, the examination of gravity waves and the quantification of processes controlling atmospheric composition in the UTLS, a region of particular importance for climate change. Simulations based on the performance requirements of this instrument deliver a vertical resolution that is slightly better than its vertical field-of-view (about 0.75 km) and a horizontal resolution of {approx}25km x 70 km. Non-linear end-to-end simulations for various gravity wave patterns demonstrate that the high 3-D resolution of PREMIER considerably extends the range of detectable gravity waves in terms of horizontal and vertical wavelength compared to previous observations. The second examined

  20. Sensor System Performance Evaluation and Benefits from the NPOESS Airborne Sounder Testbed-Interferometer (NAST-I)

    Science.gov (United States)

    Larar, A.; Zhou, D.; Smith, W.

    2009-01-01

    Advanced satellite sensors are tasked with improving global-scale measurements of the Earth's atmosphere, clouds, and surface to enable enhancements in weather prediction, climate monitoring, and environmental change detection. Validation of the entire measurement system is crucial to achieving this goal and thus maximizing research and operational utility of resultant data. Field campaigns employing satellite under-flights with well-calibrated FTS sensors aboard high-altitude aircraft are an essential part of this validation task. The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed-Interferometer (NAST-I) has been a fundamental contributor in this area by providing coincident high spectral/spatial resolution observations of infrared spectral radiances along with independently-retrieved geophysical products for comparison with like products from satellite sensors being validated. This paper focuses on some of the challenges associated with validating advanced atmospheric sounders and the benefits obtained from employing airborne interferometers such as the NAST-I. Select results from underflights of the Aqua Atmospheric InfraRed Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) obtained during recent field campaigns will be presented.

  1. Global distributions of methanol and formic acid retrieved for the first time from the IASI/MetOp thermal infrared sounder

    Directory of Open Access Journals (Sweden)

    A. Razavi

    2011-01-01

    Full Text Available Methanol (CH3OH and formic acid (HCOOH are among the most abundant volatile organic compounds present in the atmosphere. In this work, we derive the global distributions of these two organic species using for the first time the Infrared Atmospheric Sounding Interferometer (IASI launched onboard the MetOp-A satellite in 2006. This paper describes the method used and provides a first critical analysis of the retrieved products. The retrieval process follows a two-step approach in which global distributions are first obtained on the basis of a simple radiance indexing (transformed into brightness temperatures, and then mapped onto column abundances using suitable conversion factors. For methanol, the factors were calculated using a complete retrieval approach in selected regions. In the case of formic acid, a different approach, which uses a set of forward simulations for representative atmospheres, has been used. In both cases, the main error sources are carefully determined: the average relative error on the column for both species is estimated to be about 50%, increasing to about 100% for the least favorable conditions. The distributions for the year 2009 are discussed in terms of seasonality and source identification. Time series comparing methanol, formic acid and carbon monoxide in different regions are also presented.

  2. Evaluation of upwelling infrared radiance in a nonequilibrium nonhomogeneous atmosphere

    Science.gov (United States)

    Tiwari, S. N.; Subramanian, S. V.

    1982-01-01

    The influence of vibrational nonequilibrium upon upwelling infrared radiance from the earth's atmosphere is investigated. By employing the line-by-line model for spectral absorption, heating rates and upwelling radiances are calculated for equilibrium and nonequilibrium conditions in the spectral range of 4.7 micron CO and 3.3 micron CH4 bands. Heating rates are calculated also for the 15 micron CO2 band and are compared with other available results in the literature. For the spectral range of the CO fundamental band, the influence of different parameters on the upwelling radiance is investigated. It is found that for CO the assumption of local thermodynamic equilibrium (LTE) is not justified at tropospheric temperatures and pressures. If the resonance effects of CO-N2 collisions are considered, then the assumption of LTE is justified up to 60 kilometers. This information is very useful for measurement of atmospheric pollutants, earth radiation budget studies and climate modeling, and infrared signature works.

  3. Memory efficient atmospheric effects modeling for infrared scene generators

    Science.gov (United States)

    Kavak, Çaǧlar; Özsaraç, Seçkin

    2015-05-01

    The infrared (IR) energy radiated from any source passes through the atmosphere before reaching the sensor. As a result, the total signature captured by the IR sensor is significantly modified by the atmospheric effects. The dominant physical quantities that constitute the mentioned atmospheric effects are the atmospheric transmittance and the atmospheric path radiance. The incoming IR radiation is attenuated by the transmittance and path radiance is added on top of the attenuated radiation. In IR scene simulations OpenGL is widely used for rendering purposes. In the literature there are studies, which model the atmospheric effects in an IR band using OpenGLs exponential fog model as suggested by Beers law. In the standard pipeline of OpenGL, the related fog model needs single equivalent OpenGL variables for the transmittance and path radiance, which actually depend on both the distance between the source and the sensor and also on the wavelength of interest. However, in the conditions where the range dependency cannot be modeled as an exponential function, it is not accurate to replace the atmospheric quantities with a single parameter. The introduction of OpenGL Shading Language (GLSL) has enabled the developers to use the GPU more flexible. In this paper, a novel method is proposed for the atmospheric effects modeling using the least squares estimation with polynomial fitting by programmable OpenGL shader programs built with GLSL. In this context, a radiative transfer model code is used to obtain the transmittance and path radiance data. Then, polynomial fits are computed for the range dependency of these variables. Hence, the atmospheric effects model data that will be uploaded in the GPU memory is significantly reduced. Moreover, the error because of fitting is negligible as long as narrow IR bands are used.

  4. Atmospheric density remote sensing of mesosphere and thermosphere to be used for spacecraft design by adopting VHF radar and HF Doppler sounder at low latitude West Pacific site during winter

    Science.gov (United States)

    Hung, R. J.; Lee, C. C.; Chen, A. J.

    The VHF radar and HF Doppler sounder located at the subtropical and low latitude observing site of Taiwan has been used to make a simultaneous observation for atmospheric parameters from the troposphere, to the middle atmosphere, and then to the thermosphere during the time period of the weak convective motions of cold front in winter time. For observations at mesospheric heights, time dependent wind velocities with three-dimensional profiles are detected in the backscattered power, radial velocities and Doppler spectral width. For observations at thermospheric heights, time-dependent phase path change of high frequency radio wave reflected from ionospheric heights is used to measure Doppler frequency variation of gravity wave parameters. The density perturbations caused by the propagation of the gravity waves due to the weak convective motions in winter time were calculated from the VHF radar and HF Doppler sounder observations simultaneously. These short-term middle atmospheric and thermospheric density changes are a key element needed for space vehicle design purposes. Projects such as the Space Shuttle, Shuttle II, Tethered Satellite, Hubble Space Telescope, Aerobraking Orbital Transfer Vehicle, and Aeroassisted Flight Experiment will benefit from such studies.

  5. NESDIS Microwave Sounder-based Tropical Cyclone (TC) Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The S-NPP Microwave Sounder-based Tropical Cyclone (TC) Products provide estimates of tropical cyclone maximum wind speed, minimum sea level pressure, radii of 34,...

  6. Vehicle/Atmosphere Interaction Glows: Far Ultraviolet, Visible, and Infrared

    Science.gov (United States)

    Swenson, G.

    1999-10-01

    Spacecraft glow information has been gathered from a number of spacecraft including Atmospheric and Dynamic satellites, and Space Shuttles (numerous flights) with dedicated pallet flow observations on STS-39 (DOD) and STS-62 (NASA). In addition, a larger number of laboratory experiments with low energy oxygen beam studies have made important contributions to glow understanding. The following report provides information on three engineering models developed for spacecraft glow including the far ultraviolet to ultraviolet (1400-4000 A), and infrared (0.9-40 microns) spectral regions. The models include effects resulting from atmospheric density/altitude, spacecraft temperature, spacecraft material, and ram angle. Glow brightness would be predicted as a function of distance from surfaces for all wavelengths.

  7. Summertime tropospheric ozone assessment over the Mediterranean region using the thermal infrared IASI/MetOp sounder and the WRF-Chem model

    Directory of Open Access Journals (Sweden)

    S. Safieddine

    2014-05-01

    Full Text Available Over the Mediterranean region, elevated tropospheric ozone (O3 values are recorded, especially in summer. We use the Infrared Atmospheric Sounding Interferometer (IASI and the Weather Research and Forecasting Model with Chemistry (WRF-Chem to understand and interpret the factors and emission sources responsible for the high O3 concentrations observed in the Mediterranean troposphere. Six years of IASI data have been analyzed and show consistent maxima during summer, with an increase of up to 22% in the [0–8] km O3 column in the eastern part of the basin compared to the middle of the basin. We analyze 2010 as an example year to investigate the processes that contribute to these summer maxima. Using two modeled O3 tracers (inflow to the model domain and local anthropogenic emissions, we show that between the surface and 2 km, O3 is mostly formed from anthropogenic emissions and above 4 km, is mostly transported from outside the domain. Evidence of stratosphere to troposphere exchanges (STE in the eastern part of the basin is shown, and corresponds with low relative humidity and high potential vorticity.

  8. Development of a GPU-based high-performance radiative transfer model for the Infrared Atmospheric Sounding Interferometer (IASI)

    International Nuclear Information System (INIS)

    Satellite-observed radiance is a nonlinear functional of surface properties and atmospheric temperature and absorbing gas profiles as described by the radiative transfer equation (RTE). In the era of hyperspectral sounders with thousands of high-resolution channels, the computation of the radiative transfer model becomes more time-consuming. The radiative transfer model performance in operational numerical weather prediction systems still limits the number of channels we can use in hyperspectral sounders to only a few hundreds. To take the full advantage of such high-resolution infrared observations, a computationally efficient radiative transfer model is needed to facilitate satellite data assimilation. In recent years the programmable commodity graphics processing unit (GPU) has evolved into a highly parallel, multi-threaded, many-core processor with tremendous computational speed and very high memory bandwidth. The radiative transfer model is very suitable for the GPU implementation to take advantage of the hardware's efficiency and parallelism where radiances of many channels can be calculated in parallel in GPUs. In this paper, we develop a GPU-based high-performance radiative transfer model for the Infrared Atmospheric Sounding Interferometer (IASI) launched in 2006 onboard the first European meteorological polar-orbiting satellites, METOP-A. Each IASI spectrum has 8461 spectral channels. The IASI radiative transfer model consists of three modules. The first module for computing the regression predictors takes less than 0.004% of CPU time, while the second module for transmittance computation and the third module for radiance computation take approximately 92.5% and 7.5%, respectively. Our GPU-based IASI radiative transfer model is developed to run on a low-cost personal supercomputer with four GPUs with total 960 compute cores, delivering near 4 TFlops theoretical peak performance. By massively parallelizing the second and third modules, we reached 364x

  9. Accurate, practical simulation of satellite infrared radiometer spectral data

    International Nuclear Information System (INIS)

    This study's purpose is to determine whether a relatively simple random band model formulation of atmospheric radiation transfer in the infrared region can provide valid simulations of narrow interval satellite-borne infrared sounder system data. Detailed ozonesondes provide the pertinent atmospheric information and sets of calibrated satellite measurements provide the validation. High resolution line-by-line model calculations are included to complete the evaluation

  10. Prediction of transmissivity of the intervening atmosphere for infrared signature studies

    Science.gov (United States)

    Mahulikar, Shripad P.

    This paper outlines a quick method of estimating the transmissivity of the intervening atmosphere (between the infrared detector and the object to be detected - aircraft/missile), for vertical and slant beams of infrared radiation. The data needed is the transmissivity for horizontal beams of infrared radiation, of a given length, at various altitudes. The intervening atmosphere is discretized into regions of contstant extinction coefficients, and the tranmissivities of these regions are multiplied together to find the transmissivity of the intervening atmosphere.

  11. Infrared Absorption by Atmospheric Aerosols in Mexico City during MILAGRO.

    Science.gov (United States)

    Kelley, K. L.; Mangu, A.; Gaffney, J. S.; Marley, N. A.

    2007-12-01

    found as colloidal materials in surface and groundwaters (4). Examples of the IR spectra obtained and variance as a function of time at the two sites will be presented. The spectra are taken in Kubelka - Munk format, which also allows the infrared absorption strengths to be evaluated as function of wavelength. The wavelength dependence of the aerosol complex refractive index (m = n + ik) in the infrared spectral region is determined by application of the Kramers Kronig function. The importance of the aerosol absorption in the infrared spectral region to radiative forcing will be discussed. 1. N.A. Marley, J.S. Gaffney, and M.M. Cunningham,Environ. Sci. Technol. 27 2864-2869 (1993). 2. N.A. Marley, J.S. Gaffney, and M.M. Cunningham, Spectroscopy 7 44-53 (1992). 3. J.S. Gaffney and N.A. Marley, Atmospheric Environment, New Directions contribution, 32, 2873-2874 (1998). 4. N.A. Marley, J.S. Gaffney, and K.A. Orlandini, Chapter 7 in Humic/Fulvic Acids and Organic Colloidal Materials in the Environment, ACS Symposium Series 651, American Chemical Society, Washington, D.C., pp. 96-107, 1996. This work was performed as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX- Mex) under the support of the Atmospheric Science Program. This research was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-07ER64328.

  12. The research on the effect of atmospheric transmittance for the measuring accuracy of infrared thermal imager

    Science.gov (United States)

    Zhang, Yu-cun; Chen, Yi-ming; Fu, Xian-bin; Luo, Cheng

    2016-07-01

    The effect of atmospheric transmittance on infrared thermal imager temperature measuring accuracy cannot be ignored when the object is far from infrared thermal imager. In this paper, a method of reducing the influence of atmospheric transmittance is proposed for the infrared thermal imager. Firstly, the temperature measuring formula of infrared thermal imager and the effect of atmospheric transmittance on temperature measuring accuracy is analyzed. According to the composition of the atmosphere, the main factors influencing the atmosphere transmittance are determined. Secondly, the temperature measuring model of infrared thermal imager in sea level is established according to the absorption of water vapor and carbon dioxide, the scattering of air molecules and aerosol particulate, and the attenuation effects of weather conditions such as rain and snow. Finally, the correctness and feasibility of the proposed model is verified by the comparison experiments of four different environmental conditions. According to the experiments, the temperature measuring accuracy of the infrared thermal imager is improved.

  13. Apollo lunar sounder experiment

    Science.gov (United States)

    Phillips, R.J.; Adams, G.F.; Brown, W.E., Jr.; Eggleton, R.E.; Jackson, P.; Jordan, R.; Linlor, W.I.; Peeples, W.J.; Porcello, L.J.; Ryu, J.; Schaber, G.; Sill, W.R.; Thompson, T.W.; Ward, S.H.; Zelenka, J.S.

    1973-01-01

    The scientific objectives of the Apollo lunar sounder experiment (ALSE) are (1) mapping of subsurface electrical conductivity structure to infer geological structure, (2) surface profiling to determine lunar topographic variations, (3) surface imaging, and (4) measuring galactic electromagnetic radiation in the lunar environment. The ALSE was a three-frequency, wide-band, coherent radar system operated from lunar orbit during the Apollo 17 mission.

  14. Infrared properties of atmospheric aerosol constituents. Polyaromatic hydrocarbons and terpenes

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, R.A. (Army Research Lab., White Sands Missile Range, NM (United States)); Khanna, R.K.; Ospina, M.J. (Univ. of Maryland, College Park, MD (United States))

    1994-01-01

    The infrared spectra (2-20 [mu]m) of six terpene samples and six polyaromatic hydrocarbon (PAH) samples are presented and compared with similar spectra obtained from standard grade petroleum (fog oil) samples. The selected samples are representative of the various different molecular structures that may be present in atmospheric aerosol sources, particularly fire smokes. Results are presented in terms of the wavelength-dependent complex refractive indices as obtained from bulk phase (thin layer) transmittance measurements and the Kramers-Kronig relationships. All samples exhibit a characteristic complex absorption spectra with numerous line absorption features in the 8-14-[mu]m atmospheric window regions with peak imaginary indices nominally around 0.10-0.12 for the terpene samples and on the order of 1.0-1.2 for the PAH samples, although there are far fewer lines in the PAH samples than in the terpene samples. The terpene also exhibit absorption features in the 3-5 [mu]m window which are much like those found in the standard samples but are not observed in the PAH samples. 24 refs., 4 figs., 1 tab.

  15. A Fourier transform infrared trace gas analyser for atmospheric applications

    Directory of Open Access Journals (Sweden)

    D. W. T. Griffith

    2012-05-01

    Full Text Available Concern in recent decades about human impacts on Earth's climate has led to the need for improved and expanded measurement capabilities for greenhouse gases in the atmosphere. In this paper we describe in detail an in situ trace gas analyser based on Fourier Transform Infrared (FTIR spectroscopy that is capable of simultaneous and continuous measurements of carbon dioxide (CO2, methane (CH4, carbon monoxide (CO, nitrous oxide (N2O and 13C in CO2 in air with high precision and accuracy. Stable water isotopes can also be measured in undried airstreams. The analyser is automated and allows unattended operation with minimal operator intervention. Precision and accuracy meet and exceed the compatibility targets set by the World Meteorological Organisation – Global Atmosphere Watch Programme for baseline measurements in the unpolluted troposphere for all species except 13C in CO2.

    The analyser is mobile and well suited to fixed sites, tower measurements, mobile platforms and campaign-based measurements. The isotopic specificity of the optically-based technique and analysis allows application of the analyser in isotopic tracer experiments, for example 13C in CO2 and 15N in N2O. We review a number of applications illustrating use of the analyser in clean air monitoring, micrometeorological flux and tower measurements, mobile measurements on a train, and soil flux chamber measurements.

  16. Limb-atmospheric infrared spectrum observed on the satellite Ohzora

    International Nuclear Information System (INIS)

    The Institute of Space and Astronautical Science (ISAS) launched the 9th scientific satellite Ohzora at 17:00 JST on February 14, 1984. This satellite bears the spectrometer, which measures the infrared spectrum of the solar radiation passing the limb atmosphere in the wavelength region of 2 to 10 m. The spectrometer is based on multichannel spectroscopy by using image sensors. Since the wavelength is scanned electronically, it can measure the spectrum unaffected by the satellite motion. A definite axis, i.e., the Z-axis of the satellite, which coincides to the optical axis of the spectrometer, is controlled to the direction of the Sun, and the finer control to introduce the solar light into the spectrometer is made with a 2-axes-controlled mirror. This solar tracking equipment is derived fast enough to measure the spectra in a moment after sunrise. The solar light introduced into the spectrometer is focused on the slits of the monochromators (f=100mm). For better altitude resolution, the horizontal slit is also used with the vertical slit, which is used for the separation of the dispersion. The dispersion light is detected with the pyroelectric array sensors. To obtain maximum dynamic range and spectral resolution, the three-stage polychromator is used

  17. Demonstration of superconducting sub-millimeter-wave limb emission sounder (SMILES) for observing trace gases in the middle atmosphere using the exposed facility of the Japanese experimental module (JEM) of the international space station

    Science.gov (United States)

    Masuko, Harunobu; Manabe, Takeshi; Seta, Masumichi; Kasai, Yasuko; Ochiai, Satoshi; Irimajiri, Yoshihisa; Inatani, Junji; Ikeda, Naomi; Nishibori, Toshiyuki; Iida, Yukiei; Fujii, Yasunori

    1999-01-01

    The sub-millimeter wavelength region is advantageous for high-precision observations of trace species in the stratosphere. A Superconducting Sub-Millimeter-wave Limb Emission Sounder (SMILES) is scheduled to demonstrate the measurements of extremely faint sub-millimeter-wave emissions of the atmospheric trace gases on the Exposed Facility (EF) of the Japanese Experimental Module (JEM) of the International Space Station in 2003. The applications of superconductivity and mechanical 4K-refrigerator in space will be demonstrated in the experiment. JEM/SMILES obtains the diurnal and seasonal variability in the global three-dimensional distributions of the stratospheric trace gases for quantitative understanding of the stratospheric ozone depletion and its effect on the climate change with respect to the relationships among chemical reaction processes and their relationships with atmospheric dynamics. JEM/SMILES utilizes the 640GHz band to measure the vertical profiles of trace gases involved in the stratospheric ozone depletion such as chlorine monoxide (CLO), bromine monoxide (BrO), etc., along with atmospheric temperature. JEM/SMILES employs Superconductor-Insulator-Superconductor (SIS) mixers to improve measurement precision and spatial resolution, thereby enabling us to quantitatively understand the interactive processes between chemistry and dynamics.

  18. Requirements for an Advanced Low Earth Orbit (LEO) Sounder (ALS) for improved regional weather prediction and monitoring of greenhouse gases

    Science.gov (United States)

    Pagano, Thomas S.; Chahine, Moustafa T.; Susskind, Joel

    2008-12-01

    Hyperspectral infrared atmospheric sounders (e.g. the Atmospheric Infrared Sounder (AIRS) on Aqua and the Infrared Atmospheric Sounding Interferometer (IASI) on MetOp) provide highly accurate temperature and water vapor profiles in the lower to upper troposphere. These systems are vital operational components of our National Weather Prediction system and the AIRS has demonstrated over 6 hrs of forecast improvement on the 5 day operational forecast1. Despite the success in the mid troposphere to lower stratosphere, a reduction in sensitivity and accuracy has been seen in these systems in the boundary layer over land. In this paper we demonstrate the potential improvement associated with higher spatial resolution (1km vs currently 13.5 km) on the accuracy of boundary layer products with an added consequence of higher yield of cloud free scenes. This latter feature is related to the number of samples that can be assimilated and has also shown to have a significant impact on improving forecast accuracy. We also present a set of frequencies and resolutions that will improve vertical resolution of temperature and water vapor and trace gas species throughout the atmosphere. Development of an Advanced Low Earth Orbit (LEO) Sounder (ALS) with these improvements will improve weather forecast at the regional scale and of tropical storms and hurricanes. Improvements are also expected in the accuracy of the water vapor and cloud properties products, enhancing process studies and providing a better match to the resolution of future climate models. The improvements of technology required for the ALS are consistent with the current state of technology as demonstrated in NASA Instrument Incubator Program and NOAA's Hyperspectral Environmental Suite (HES) formulation phase development programs.

  19. Requirements for an Advanced Low Earth Orbit (LEO) Sounder (ALS) for Improved Regional Weather Prediction and Monitoring of Greenhouse Gases

    Science.gov (United States)

    Pagano, Thomas S.; Chahine, Moustafa T.; Susskind, Joel

    2008-01-01

    Hyperspectral infrared atmospheric sounders (e.g., the Atmospheric Infrared Sounder (AIRS) on Aqua and the Infrared Atmospheric Sounding Interferometer (IASI) on Met Op) provide highly accurate temperature and water vapor profiles in the lower to upper troposphere. These systems are vital operational components of our National Weather Prediction system and the AIRS has demonstrated over 6 hrs of forecast improvement on the 5 day operational forecast. Despite the success in the mid troposphere to lower stratosphere, a reduction in sensitivity and accuracy has been seen in these systems in the boundary layer over land. In this paper we demonstrate the potential improvement associated with higher spatial resolution (1 km vs currently 13.5 km) on the accuracy of boundary layer products with an added consequence of higher yield of cloud free scenes. This latter feature is related to the number of samples that can be assimilated and has also shown to have a significant impact on improving forecast accuracy. We also present a set of frequencies and resolutions that will improve vertical resolution of temperature and water vapor and trace gas species throughout the atmosphere. Development of an Advanced Low Earth Orbit (LEO) Sounder (ALS) with these improvements will improve weather forecast at the regional scale and of tropical storms and hurricanes. Improvements are also expected in the accuracy of the water vapor and cloud properties products, enhancing process studies and providing a better match to the resolution of future climate models. The improvements of technology required for the ALS are consistent with the current state of technology as demonstrated in NASA Instrument Incubator Program and NOAA's Hyperspectral Environmental Suite (HES) formulation phase development programs.

  20. Atmospheric temperature sensing with a multiorder Fabry-Perot interferometer.

    Science.gov (United States)

    Wang, J; Drayson, S R; Hayes, P B

    1989-12-01

    A Fabry-Perot interferometer has a periodic response. By matching the free spectral range of a Fabry-Perot interferometer (FPI) with the period of the CO(2) spectrum, considerable advantages of throughput and spectral resolution can be achieved, leading to high spectral resolution and vertical resolution for atmospheric temperature sounders. In this paper, the concept of a high resolution multiorder Fabry-Perot interferometer using portions of the 15-microm and 4.3-microm bands of CO(2)for the purpose of atmospheric temperature sounding is discussed. Suitable sounding spectral positions, FPI free spectral range, and weighting functions are calculated. An effective spectral resolution of 0.02 cm(-1) can be achieved by the proposed sounder with a FPI finess of ~100 which is within the present state-of-the-art technology in the infrared region, leading to considerable improvement in the vertical resolution of the atmospheric temperature sounder. PMID:20555996

  1. Interannual Variability of Dust and Ice in the Mars Atmosphere: Comparison of MRO Mars Climate Sounder Retrievals with MGS-TES Limb Sounding Retrievals

    Science.gov (United States)

    Shirley, J. H.; McConnochie, T. H.; Kleinbohl, A.; Schofield, J. T.; Kass, D.; Heavens, N. G.; Benson, J.; McCleese, D. J.

    2011-01-01

    Dust and ice play important roles in Martian atmospheric dynamics on all time scales. Dust loading in particular exerts an important control on atmospheric temperatures and thereby on the strength of the atmospheric circulation in any given year. We present the first comparisons of MGS-TES aerosol opacity profiles with MRO-MCS aerosol opacity profiles. While the differences in vertical resolution are significant (a factor of 2), we find good agreement at particular seasons between nightside zonal average dust opacity profiles from the two instruments. Derived water ice opacities are likewise similar but show greater variability.

  2. Latest developments of geostationary microwave sounder technologies for NOAA's mission

    Science.gov (United States)

    Bajpai, Shyam; Madden, Michael; Chu, Donald; Yapur, Martin

    2006-12-01

    The National Oceanic and Atmospheric Administration (NOAA) have been flying microwave sounders since 1975 on Polar Operational Environmental Satellites (POES). Microwave observations have made significant contributions to the understanding of the atmosphere and earth surface. This has helped in improving weather and storm tracking forecasts. However, NOAA's Geostationary Operational Environmental Satellites (GOES) have microwave requirements that can not be met due to the unavailability of proven technologies. Several studies of a Geostationary Microwave Sounder (GMS) have been conducted. Among those, are the Geostationary Microwave Sounder (GEM) that uses a mechanically steered solid dish antenna and the Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) that utilizes a sparse aperture array. Both designs take advantage of the latest developments in sensor technology. NASA/Jet Propulsion Lab (JPL) has recently successfully built and tested a prototype ground-based GeoSTAR at 50 GHz frequency with promising test results. Current GOES IR Sounders are limited to cloud top observations. Therefore, a sounding suite of IR and Microwave should be able to provide observations under clear as well as cloudy conditions all the time. This paper presents the results of the Geostationary Microwave Sounder studies, user requirements, frequencies, technologies, limitations, and implementation strategies.

  3. Measure and exploitation of multisensor and multiwavelength synergy for remote sensing: 2. Application to the retrieval of atmospheric temperature and water vapor from MetOp

    OpenAIRE

    Aires, F.; Paul, M; Prigent, C; Rommen, B.; Bouvet, M

    2011-01-01

    In the companion paper, classical information content (IC) analysis was used to measure the potential synergy between the microwave (MW) and infrared (IR) observations from Atmospheric Microwave Sounding Unit-A, Microwave Humidity Sounder, and Improved Atmospheric Sounding in the Infrared instruments, used to retrieve the atmospheric profiles of temperature and water vapor over ocean, under clear-sky conditions. Some limitations of IC were pointed out that questioned the reliability of this t...

  4. Assessment of global atmospheric ammonia using IASI infrared satellite observations

    OpenAIRE

    M. Van Damme

    2015-01-01

    ENGLISH:The natural nitrogen cycle has been and is significantly perturbed by anthropogenic emissions of reactive nitrogen (Nr) compounds into the atmosphere, resulting from our production of energy and food. In the last century global ammonia (NH3) emissions have doubled and represent nowadays more than half of total the Nr emissions. NH3 is also the principal atmospheric base in the atmosphere and rapidly forms aerosols by reaction with acids. It is therefore a species of high relevance for...

  5. Mars Atmospheric CO2 Condensation Above the North and South Poles as Revealed by Radio Occultation, Climate Sounder, and Laser Ranging Observations

    Science.gov (United States)

    Hu, Renyu; Cahoy, Kerri; Zuber, Maria T.

    2012-01-01

    We study the condensation of CO2 in Mars atmosphere using temperature profilesretrieved from radio occultation measurements from Mars Global Surveyor (MGS) as wellas the climate sounding instrument onboard the Mars Reconnaissance Orbiter (MRO),and detection of reflective clouds by the MGS Mars Orbiter Laser Altimeter (MOLA). Wefind 11 events in 1999 where MGS temperature profiles indicate CO2 condensation andMOLA simultaneously detects reflective clouds. We thus provide causal evidence thatMOLA non-ground returns are associated with CO2 condensation, which strongly indicatestheir nature being CO2 clouds. The MGS and MRO temperature profiles together revealthe seasonal expansion and shrinking of the area and the vertical extent of atmosphericsaturation. The occurrence rate of atmospheric saturation is maximized at high latitudes inthe middle of winter. The atmospheric saturation in the northern polar region exhibits moreintense seasonal variation than in the southern polar region. In particular, a shrinking ofsaturation area and thickness from LS 270 to 300 in 2007 is found; this is probablyrelated to a planet-encircling dust storm. Furthermore, we integrate the condensation areaand the condensation occurrence rate to estimate cumulative masses of CO2 condensatesdeposited onto the northern and southern seasonal polar caps. The precipitation flux isapproximated by the particle settling flux which is estimated using the impulse responses ofMOLA filter channels. With our approach, the total atmospheric condensation mass canbe estimated from these observational data sets with average particle size as the onlyfree parameter. By comparison with the seasonal polar cap masses inferred from thetime-varying gravity of Mars, our estimates indicate that the average condensate particleradius is 822 mm in the northern hemisphere and 413 mm in the southern hemisphere.Our multi-instrument data analysis provides new constraints on modeling the global climateof Mars.

  6. Characteristics of monsoon inversions over the Arabian Sea observed by satellite sounder and reanalysis data sets

    Science.gov (United States)

    Dwivedi, Sanjeev; Narayanan, M. S.; Venkat Ratnam, M.; Narayana Rao, D.

    2016-04-01

    Monsoon inversion (MI) over the Arabian Sea (AS) is one of the important characteristics associated with the monsoon activity over Indian region during summer monsoon season. In the present study, we have used 5 years (2009-2013) of temperature and water vapour measurement data obtained from satellite sounder instrument, an Infrared Atmospheric Sounding Interferometer (IASI) onboard MetOp satellite, in addition to ERA-Interim data, to study their characteristics. The lower atmospheric data over the AS have been examined first to identify the areas where MIs are predominant and occur with higher strength. Based on this information, a detailed study has been made to investigate their characteristics separately in the eastern AS (EAS) and western AS (WAS) to examine their contrasting features. The initiation and dissipation times of MIs, their percentage occurrence, strength, etc., has been examined using the huge database. The relation with monsoon activity (rainfall) over Indian region during normal and poor monsoon years is also studied. WAS ΔT values are ˜ 2 K less than those over the EAS, ΔT being the temperature difference between 950 and 850 hPa. A much larger contrast between the WAS and EAS in ΔT is noticed in ERA-Interim data set vis-à-vis those observed by satellites. The possibility of detecting MI from another parameter, refractivity N, obtained directly from another satellite constellation of GPS Radio Occultation (RO) (COSMIC), has also been examined. MI detected from IASI and Atmospheric Infrared Sounder (AIRS) onboard the NOAA satellite have been compared to see how far the two data sets can be combined to study the MI characteristics. We suggest MI could also be included as one of the semipermanent features of southwest monsoon along with the presently accepted six parameters.

  7. Evaluation of upwelling infrared radiance from earth's atmosphere

    Science.gov (United States)

    Gupta, S. K.; Tiwari, S. N.

    1975-01-01

    Basic equations for calculating the upwelling atmospheric radiation are presented which account for various sources of radiation coming out at the top of the atmosphere. The theoretical formulation of the transmittance models (line-by-line and quasi-random band model) and the computational procedures used for the evaluation of the transmittance and radiance are discussed in detail. By employing the Lorentz line-by-line and quasi-random computer programs, model calculations were made to determine the upwelling radiance and signal change in the wave number interval of CO fundamental band. These results are useful in determining the effects of different interfering molecules, water vapor profiles, ground temperatures, and ground emittances on the upwelling radiance and signal change. This information is of vital importance in establishing the feasibility of measuring the concentrations of pollutants in the atmosphere from a gas filter correlation instrument flown on an aircraft or mounted on a satellite.

  8. Determining Atmospheric Aerosol Content With An Infra-red Radiometer

    CERN Document Server

    Daniel, M K; Chadwick, P M

    2014-01-01

    The atmospheric attenuation of Cherenkov photons is dominated by two processes: Rayleigh scattering from the molecular component and Mie scattering from the aerosol component. Aerosols are expected to contribute up to 30 Wm$^{-2}$ to the emission profile of the atmosphere, equivalent to a difference of ~20C to the clear sky brightness temperature under normal conditions. Here we investigate the aerosol contribution of the measured sky brightness temperature at the H.E.S.S. site; compare it to effective changes in the telescope trigger rates; and discuss how it can be used to provide an assessment of sky clarity that is unambiguously free of telescope systematics.

  9. Determining atmospheric aerosol content with an infra-red radiometer

    CERN Document Server

    Daniel, Michael; 10.1063/1.4772360

    2012-01-01

    The attenuation of atmospheric Cherenkov photons is dominated by two processes: Rayleigh scattering from the molecular component and Mie scattering from the aerosol component. Aerosols are expected to contribute up to 30 Wm$^{-2}$ to the emission profile of the atmosphere, equivalent to a difference of $\\sim20^\\circ$C to the clear sky brightness temperature under normal conditions. Here we investigate the aerosol contribution of the measured sky brightness temperature at the H.E.S.S. site; compare it to effective changes in the telescope trigger rates; and discuss how it can be used to provide an assessment of sky clarity that is unambiguously free of telescope systematics.

  10. Optimizing an Infrared Camera for Observing Atmospheric Gravity Waves from a CubeSat Platform

    OpenAIRE

    Rønning, Snorre Stavik

    2012-01-01

    The NTNU Test Satellite (NUTS) is a double CubeSat deigned by master students at NTNU. The goal of the project is to image atmospheric gravity waves in the OH airglow layer. This thesis explores the theory behind gravity waves and discuss the design of an infrared camera as a payload onboard. Different requirement based on scientific and mechanical limitations are presented. Based on this a suitable infrared camera is presented.

  11. New Asia Dust Storm Detection Method Based on the Thermal Infrared Spectral Signature

    OpenAIRE

    Hui Xu; Tianhai Cheng; Xingfa Gu; Tao Yu; Yu Wu; Hao Chen

    2014-01-01

    As hyperspectral instruments can provide the detailed spectral information, a new spectral similarity method for detecting and differentiating dust from non-dust scenes using the Atmospheric Infrared Sounder (AIRS) observations has been developed. The detection is based on a pre-defined Dust Spectral Similarity Index (DSSI), which was calculated from the accumulated brightness temperature differences between selected 16 AIRS observation channels, in the thermal infrared region of 800–1250 cm−...

  12. Retrieval with Infrared Atmospheric Sounding Interferometer and Validation during JAIVEx

    Science.gov (United States)

    Zhou, Daniel K.; Liu, Xu; Larar, Allen M.; Smith, William L.; Taylor, Jonathan P.; Schluessel, Peter; Strow, L. Larrabee; Mango, Stephen A.

    2008-01-01

    A state-of-the-art IR-only retrieval algorithm has been developed with an all-season-global EOF Physical Regression and followed by 1-D Var. Physical Iterative Retrieval for IASI, AIRS, and NAST-I. The benefits of this retrieval are to produce atmospheric structure with a single FOV horizontal resolution (approx. 15 km for IASI and AIRS), accurate profiles above the cloud (at least) or down to the surface, surface parameters, and/or cloud microphysical parameters. Initial case study and validation indicates that surface, cloud, and atmospheric structure (include TBL) are well captured by IASI and AIRS measurements. Coincident dropsondes during the IASI and AIRS overpasses are used to validate atmospheric conditions, and accurate retrievals are obtained with an expected vertical resolution. JAIVEx has provided the data needed to validate the retrieval algorithm and its products which allows us to assess the instrument ability and/or performance. Retrievals with global coverage are under investigation for detailed retrieval assessment. It is greatly desired that these products be used for testing the impact on Atmospheric Data Assimilation and/or Numerical Weather Prediction.

  13. Microwave limb sounder for stratospheric measurements

    International Nuclear Information System (INIS)

    The balloon-borne Microwave Limb Sounder (BMLS) measures atmospheric thermal emission from millimeter wavelength spectral lines to determine vertical profiles of stratospheric species. The instrument flown to data operates at 205 BHz to measure ClO, O3, and H2O2. A 63 GHz radiometer is added to test the technique for determining tangent point pressure from the MLS experiment on the Upper Atmosphere Research Satellite (UARS). Many additional species is also measured by the BLMS. A radiometer at 270 GHz would provide measurements of HO2, NO2, HNO3, N2O, 16O18O16O, and HCN. With this addition the BMLS can test the current theory of O3 heavy ozone photochemical balance in the upper stratosphere

  14. Arctic Precipitable Water Measurements and Comparisons using the Microwave Humidity Sounder

    Science.gov (United States)

    Perro, C. W.; Lesins, G. B.; Duck, T.; Nott, G. J.; Doyle, J.; Pike-thackray, C.; Hopper, J.; McCullough, E. M.; Drummond, J. R.

    2013-12-01

    The Microwave Humidity Sounder (MHS) is an instrument onboard the polar orbiting NOAA-18 and MetOp-A satellites. MHS measures the brightness temperatures at five channels near 183 GHz for the purpose of measuring water vapour column without significant interference from ice or water clouds. The water vapour retrieval technique is independent of surface emissivity and favours low column amounts of water vapour (generate Pan-Arctic plots, which can be produced twice-daily with 15 km resolution at nadir. This technique can also be applied to other satellite instruments that measure brightness temperatures near 183 GHz, which include the Advanced Technology Microwave Sounder (ATMS), Microwave Humidity Sounder (MWHS), and Advanced Microwave Sounding Unit (AMSU-B). The addition of these instruments allows for an increase in the temporal resolution of the precipitable water fields. An assessment of the Arctic radiosonde network will be shown to test the results of the new MHS calibration and to show the quality of water vapour measurements at each station. A comparison of the MHS calibration with the satellite-borne Atmospheric Infrared Sounder (AIRS) instrument was done with the the G-Band Water Vapour Radiometer (GVR), located in Barrow. Alaska (71N, 156W). A case study of a thick precipitating ice cloud extending from the surface to the tropopause will be shown as measured by the CANDAC Rayleigh-Mie-Raman lidar (CRL), located in Eureka, Nunavut (80N, 86W). Pan-Arctic maps of water vapour using the MHS in combination with FLEXPART back trajectories indicate two possible water vapour masses contributing to the formation of the thick ice cloud. Thick precipitating ice clouds occur frequently at Eureka with several cases being measured each winter by the CRL. Time evolution of the precipitable water fields can provide insight into the dehydration of the atmosphere in the Arctic. A water budget for the Arctic can be constructed using the high spatial and temporal resolution

  15. The Infrared Imaging Spectrograph (IRIS) for TMT: the atmospheric dispersion corrector

    CERN Document Server

    Phillips, Andrew C; Larkin, James E; Moore, Anna M; Niehaus, Cynthia N; Cramptone, David; Simard, Luc

    2010-01-01

    We present a conceptual design for the atmospheric dispersion corrector (ADC) for TMT's Infrared Imaging Spectrograph (IRIS). The severe requirements of this ADC are reviewed, as are limitations to observing caused by uncorrectable atmospheric effects. The requirement of residual dispersion less than 1 milliarcsecond can be met with certain glass combinations. The design decisions are discussed and the performance of the design ADC is described. Alternative options and their performance tradeoffs are also presented.

  16. Stratospheric and mesospheric HO2 observations from the Aura Microwave Limb Sounder

    Directory of Open Access Journals (Sweden)

    L. Millán

    2014-09-01

    Full Text Available This study introduces stratospheric and mesospheric hydroperoxyl radical (HO2 estimates from the Aura Microwave Limb Sounder (MLS using an offline retrieval (i.e. run separately from the standard MLS algorithm. This new dataset provides two daily zonal averages, one during daytime and one during nighttime, with a varying vertical resolution from about 4 km at 10 hPa to around 14 km at 0.0032 hPa. A description of the methodology and an error analysis are presented. Comparisons against the Whole Atmosphere Community Climate Model (WACCM, the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES and the Far Infrared Spectrometer (FIRS-2 measurements, as well as, photochemical simulations demonstrate the robustness of the retrieval and indicate that the retrieval is sensitive enough to detect mesospheric HO2 layers during both day and night. This new dataset is the first long-term HO2 stratospheric and mesospheric satellite record and it provides needed constraints to help resolve the O3 deficit problem and the "HOx dilemma".

  17. Infrared Spectral Radiance Intercomparisons With Satellite and Aircraft Sensors

    Science.gov (United States)

    Larar, Allen M.; Zhou, Daniel K.; Liu, Xu; Smith, William L.

    2014-01-01

    Measurement system validation is critical for advanced satellite sounders to reach their full potential of improving observations of the Earth's atmosphere, clouds, and surface for enabling enhancements in weather prediction, climate monitoring capability, and environmental change detection. Experimental field campaigns, focusing on satellite under-flights with well-calibrated FTS sensors aboard high-altitude aircraft, are an essential part of the validation task. Airborne FTS systems can enable an independent, SI-traceable measurement system validation by directly measuring the same level-1 parameters spatially and temporally coincident with the satellite sensor of interest. Continuation of aircraft under-flights for multiple satellites during multiple field campaigns enables long-term monitoring of system performance and inter-satellite cross-validation. The NASA / NPOESS Airborne Sounder Testbed - Interferometer (NAST-I) has been a significant contributor in this area by providing coincident high spectral/spatial resolution observations of infrared spectral radiances along with independently-retrieved geophysical products for comparison with like products from satellite sensors being validated. This presentation gives an overview of benefits achieved using airborne sensors such as NAST-I utilizing examples from recent field campaigns. The methodology implemented is not only beneficial to new sensors such as the Cross-track Infrared Sounder (CrIS) flying aboard the Suomi NPP and future JPSS satellites but also of significant benefit to sensors of longer flight heritage such as the Atmospheric InfraRed Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) on the AQUA and METOP-A platforms, respectively, to ensure data quality continuity important for climate and other applications. Infrared spectral radiance inter-comparisons are discussed with a particular focus on usage of NAST-I data for enabling inter-platform cross-validation.

  18. ATMOSPHERIC MEASUREMENTS OF TRACE POLLUTANTS; LONG PATH FOURIER TRANSFORM INFRARED SPECTROSCOPY

    Science.gov (United States)

    Described are the results of a four-year study to measure trace pollutant concentrations in polluted atmospheres by kilometer pathlength Fourier transform infrared (FT-IR) absorption spectroscopy. The study covers selected smog episodes during the years 1976 to 1979. During 1976 ...

  19. A Thermal Infrared Radiation Parameterization for Atmospheric Studies

    Science.gov (United States)

    Chou, Ming-Dah; Suarez, Max J.; Liang, Xin-Zhong; Yan, Michael M.-H.; Cote, Charles (Technical Monitor)

    2001-01-01

    This technical memorandum documents the longwave radiation parameterization developed at the Climate and Radiation Branch, NASA Goddard Space Flight Center, for a wide variety of weather and climate applications. Based on the 1996-version of the Air Force Geophysical Laboratory HITRAN data, the parameterization includes the absorption due to major gaseous absorption (water vapor, CO2, O3) and most of the minor trace gases (N2O, CH4, CFCs), as well as clouds and aerosols. The thermal infrared spectrum is divided into nine bands. To achieve a high degree of accuracy and speed, various approaches of computing the transmission function are applied to different spectral bands and gases. The gaseous transmission function is computed either using the k-distribution method or the table look-up method. To include the effect of scattering due to clouds and aerosols, the optical thickness is scaled by the single-scattering albedo and asymmetry factor. The parameterization can accurately compute fluxes to within 1% of the high spectral-resolution line-by-line calculations. The cooling rate can be accurately computed in the region extending from the surface to the 0.01-hPa level.

  20. The important role of stellar atmosphere spectra for a consistent spectrophotometric calibration from the optical to the infrared wavelengths

    Science.gov (United States)

    Decin, L.

    2008-12-01

    We discuss the role of stellar atmosphere models in the spectrophotometric calibration pedigree. It is shown that stellar atmosphere spectra form an essential ingredient for spectrophotometric calibration. Compared with other (infrared) calibration networks currently available, the marcs grid is shown to provide the calibration community with spectral reference energy distributions of higher accuracy improving the spectrophotometric calibration of infrared spectrometers by more than 3%.

  1. Common 0.1 bar Tropopause in Thick Atmospheres Set by Pressure-Dependent Infrared Transparency

    CERN Document Server

    Robinson, Tyler D

    2014-01-01

    A minimum atmospheric temperature, or tropopause, occurs at a pressure of around 0.1 bar in the atmospheres of Earth, Titan, Jupiter, Saturn, Uranus and Neptune, despite great differences in atmospheric composition, gravity, internal heat and sunlight. In all these bodies, the tropopause separates a stratosphere with a temperature profile that is controlled by the absorption of shortwave solar radiation, from a region below characterised by convection, weather, and clouds. However, it is not obvious why the tropopause occurs at the specific pressure near 0.1 bar. Here we use a physically-based model to demonstrate that, at atmospheric pressures lower than 0.1 bar, transparency to thermal radiation allows shortwave heating to dominate, creating a stratosphere. At higher pressures, atmospheres become opaque to thermal radiation, causing temperatures to increase with depth and convection to ensue. A common dependence of infrared opacity on pressure, arising from the shared physics of molecular absorption, sets t...

  2. Current Sounding Capability From Satellite Meteorological Observation With Ultraspectral Infrared Instruments

    Science.gov (United States)

    Zhou, Daniel K.; Liu, Xu; Larar, Allen M.

    2008-01-01

    Ultraspectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. The intent of the measurement of tropospheric thermodynamic state and trace abundances is the initialization of climate models and the monitoring of air quality. The NPOESS Airborne Sounder Testbed-Interferometer (NAST-I), designed to support the development of future satellite temperature and moisture sounders, aboard high altitude aircraft has been collecting data throughout many field campaigns. An advanced retrieval algorithm developed with NAST-I is now applied to satellite data collected with the Atmospheric InfraRed Sounder (AIRS) on the Aqua satellite launched on 4 May 2002 and the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite launched on October 19, 2006. These instruments possess an ultra-spectral resolution, for example, both IASI and NAST-I have 0.25 cm-1 and a spectral coverage from 645 to 2760 cm-1. The retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. The physical inversion scheme has been developed, dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders, to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A fast radiative transfer model, which applies to the clouded atmosphere, is used for atmospheric profile and cloud parameter retrieval. A one-dimensional (1-d) variational multi-variable inversion solution is used to improve an iterative background state defined by an eigenvector-regression-retrieval. The solution is iterated in order to account for non-linearity in the 1-d variational solution. It is shown that relatively accurate temperature and moisture retrievals can be achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to

  3. ARIEL: Atmospheric Remote-Sensing Infrared Exoplanet Large-survey

    Science.gov (United States)

    Tinetti, Giovanna

    2015-11-01

    More than 1,000 extrasolar systems have been discovered, hosting nearly 2,000 exoplanets. Ongoing and planned ESA and NASA missions from space such as GAIA, Cheops, PLATO, K2 and TESS will increase the number of known systems to tens of thousands.Of all these exoplanets we know very little, i.e. their orbital data and, for some of these, their physical parameters such as their size and mass. In the past decade, pioneering results have been obtained using transit spectroscopy with Hubble, Spitzer and ground-based facilities, enabling the detection of a few of the most abundant ionic, atomic and molecular species and to constrain the planet’s thermal structure. Future general purpose facilities with large collecting areas will allow the acquisition of better exoplanet spectra, compared to the currently available, especially from fainter targets. A few tens of planets will be observed with JWST and E-ELT in great detail.A breakthrough in our understanding of planet formation and evolution mechanisms will only happen through the observation of the planetary bulk and atmospheric composition of a statistically large sample of planets. This requires conducting spectroscopic observations covering simultaneously a broad spectral region from the visible to the mid-IR. It also requires a dedicated space mission with the necessary photometric stability to perform these challenging measurements and sufficient agility to observe multiple times ~500 exoplanets over mission life-time.The ESA-M4 mission candidate ARIEL is designed to accomplish this goal and will provide a complete, statistically significant sample of gas-giants, Neptunes and super-Earths with temperatures hotter than 600K, as these types of planets will allow direct observation of their bulk properties, enabling us to constrain models of planet formation and evolution.The ARIEL consortium currently includes academic institutes and industry from eleven countries in Europe; the consortium is open and invites new

  4. Hyperspectral sounding: a revolutionary advance in atmospheric remote sensing

    Science.gov (United States)

    Smith, W. L., Sr.; Revercomb, Henry E.; Zhou, Daniel K.; Huang, Hung-Lung A.

    2005-01-01

    Hyperspectral remote sounding was introduced with the High spectral resolution Interferometer Sounder (HIS) that flew on the NASA ER-2 aircraft in the mid-1980s. The results from the HIS demonstrated that high vertical resolution sounding information could be achieved using quasi-continuous spectra of the atmosphere"s radiance to space. This has led to a series of research and operational satellite instruments designed to exploit the hyperspectral resolution sounding approach. The experimental versions, the ADEOS IMG (Interferometer for the Measurement of trace Gases) and the Aqua AIRS (Atmospheric InfraRed Sounder) have already been orbited. The IASI (Infrared Atmospheric Sounding Interferometer) and the CrIS (Cross-track Infrared Sounder) instruments are soon to be orbited on the METOP and the NPP/NPOESS operational series of polar orbiting satellites, respectively. Geostationary satellite hyperspectral resolution sounding instrumentation was initiated with the experimental GIFTS (Geostationary Imaging Fourier Transform Spectrometer) instrument whose development is providing risk reduction for the next generation of operational geostationary satellite instruments (e.g., the GOES-R Hyperspectral Environmental Suite, HES). This presentation traces the evolution of the hyperspectral resolution sounding program. Intercomparisons of the different satellite instrument approaches are discussed. Experimental results from the current aircraft and experimental satellite systems are presented to demonstrate the power of the hyperspectral resolution sounding technique.

  5. Ground Based Observation of Isotopic Oxygen in the Martian Atmosphere Using Infrared Heterodyne Spectroscopy

    Science.gov (United States)

    Smith, R. L.; Kostiuk, T.; Livengood, T. A.; Fast, K. E.; Hewagama, T.; Delgado, J. D.; Sonnabend, G.

    2010-01-01

    Infrared heterodyne spectra of isotopic CO2 in the Martian atmosphere were obtained using the Goddard Heterodyne Instrument for Planetary Wind and Composition, HIPWAC, which was interfaced with the 3-meter telescope at the NASA Infrared Telescope Facility- Spectra were colle cted at a resolution of lambda/delta lambda=10(exp 7). Absorption fea tures of the CO2 isotopologues have been identified from which isotop ic ratios of oxygen have been determined. The isotopic ratios O-17/O -16 and O-18/O-16 in the Martian atmosphere can be related to Martian atmospheric evolution and can be compared to isotopic ratios of oxyg en in the Earth's atmosphere. Isotopic carbon and oxygen are importa nt constraints on any theory for the erosion of the Martian primordia l atmosphere and the interaction between the atmosphere and surface o r subsurface chemical reservoirs. This investigation explored the pr esent abundance of the stable isotopes of oxygen in Mars' atmospheric carbon dioxide by measuring rovibrational line absorption in isotop ic species of CO2 using groundbased infrared heterodyne spectroscopy in the vicinity of the 9.6 micron and 10.6 micron CO2 lasing bands. T he target transitions during this observation were O-18 C-12 O-16 as well as O-178 C-12 O-16 and O-16 C-113 O-16 at higher resolving power of lambda/delta lambda=10(exp 7) and with high signal-to-noise ratio (longer integration time) in order to fully characterize the absorpt ion line profiles. The fully-resolved lineshape of both the strong n ormal-isotope and the weak isotopic CO2 lines were measured simultane ously in a single spectrum.

  6. Measurements of C02 Distribution in Saturn's Atmosphere by Cassini-Infrared Observations

    Science.gov (United States)

    Abbas, M. M.; LeClair, A.; Woodard, E.; Young, M.; Stanbro, M.; Flasar, M.

    2013-01-01

    The Fourier transform infrared spectrometer aboard the Cassini spacecraft, inserted in Saturn s orbit in July 2004, has been providing high resolution/high sensitivity infrared (IR) spectra of the Saturnian system. The measurements cover the spectral range of 10-1400/cm with variable spectral resolutions of 0.53 to 15/cm, exhibiting spectral features of a series of trace gases including CO2 and H2O. The observed spectra may be analyzed for retrieval of global P/T and gas density profiles of Saturn. The infrared measurements of Saturn by ISO(SWS) have indicated unexpected large abundances of CO2 in Saturn's atmosphere. The rigorous photochemical models of Saturn's atmosphere that have been developed indicate exogenic oxygen influx of icy dust grains that lead to the production of CO2. The distribution of CO2 in Saturn's atmosphere needs to be confirmed, and the nature of exogenic sources remains to be investigated. This paper presents comprehensive measurements of the CO2 distribution in Saturn's atmosphere by Cassini IR observations.

  7. Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) data processing and atmospheric temperature and trace gas retrieval

    Science.gov (United States)

    Riese, M.; Spang, R.; Preusse, P.; Ern, M.; Jarisch, M.; Offermann, D.; Grossmann, K. U.

    1999-07-01

    The Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) experiment aboard the Shuttle Pallet Satellite (SPAS) was successfully flown in early November 1994 (STS 66) and in August 1997 (STS 85). This paper focuses on the first flight of the instrument, which was part of the Atmospheric Laboratory for Application and Science 3 (ATLAS 3) mission of NASA. During a free flying period of 7 days, limb scan measurements of atmospheric infrared emissions were performed in the 4 to 71 μm wavelength region. For improved horizontal resolution, three telescopes (viewing directions) were used that sensed the atmosphere simultaneously. Atmospheric pressures, temperatures, and volume mixing ratios of various trace gases were retrieved from the radiance data by using a fast onion-peeling retrieval technique. This paper gives an overview of the data system including the raw data processing and the temperature and trace gas profile retrieval. Examples of version 1 limb radiance data (level 1 product) and version 1 mixing ratios (level 2 product) of ozone, ClONO2, and CFC-11 are given. A number of important atmospheric transport processes can already be identified in the level 1 limb radiance data. Radiance data of the lower stratosphere (18 km) indicate strong upwelling in some equatorial regions, centered around the Amazon, Congo, and Indonesia. Respective data at the date line are consistent with convection patterns associated with El Niño. Very low CFC-11 mixing ratios occur inside the South Polar vortex and cause low radiance values in a spectral region sensitive to CFC-11 emissions. These low values are a result of considerable downward transport of CFC-11 poor air that occurred during the winter months. Limb radiance profiles and retrieved mixing ratio profiles of CFC-11 indicate downward transport over ˜5 km. The accuracy of the retrieved version 1 mixing ratios is rather different for the various trace gases. In the middle atmosphere the estimated

  8. Main features associated to the precipitation in Madeira and the Atmospheric rivers in the winter seasons.

    OpenAIRE

    Couto, Flavio; Salgado, Rui; Costa, Maria João

    2015-01-01

    This study presents the main features about 10-year daily accumulated precipitation analysis over the Madeira's highlands, as well as the relationships between this precipitation and the meridional water vapor transport occurring in narrow corridors, also known as atmospheric rivers (ARs). The ARs were visually identified in the total precipitable water vapor field extracted from the Atmospheric Infrared Sounder (AIRS) data, and over a domain covering the North Atlantic Ocean. When needed,...

  9. Assimilation of the Microwave Limb Sounder Radiances

    Science.gov (United States)

    Wargan, K.; Read, W.; Livesey, N.; Wagner, P.; Nguyen. H.; Pawson, S.

    2012-01-01

    It has been shown that the assimilation of limb-sounder data can significantly improve the representation of ozone in NASA's GEOS Data Assimilation Systems (GEOS-DAS), particularly in the stratosphere. The studies conducted so far utilized retrieved data from the MIPAS, POAM, ILAS and EOS Microwave Limb Sounder (EOS MLS) instruments. Direct assimilation of the radiance data can be seen as the natural next step to those studies. The motivation behind working with radiances is twofold. First, retrieval algorithms use a priori data which are either climatological or are obtained from previous analyses. This introduces additional uncertainty and, in some cases, may lead to "self-contamination"- when the a priori is taken from the same assimilation system in which subsequently ingests the retrieved observations. Second, radiances can be available in near real time thus providing an opportunity for operational assimilation, which could help improve the use of infrared radiance instruments from operational satellite instruments. In this presentation we summarize our ongoing work on an implementation of the assimilation of EOS MLS radiances into the GEOS-5 DAS. This work focuses on assimilation of band 7 brightness temperatures which are sensitive to ozone. Our implementation uses the MLS Callable Forward Model developed by the MLS team at NASA JPL as the observation operator. We will describe our approach and recent results which are not yet final. In particular, we will demonstrate that this approach has a potential to improve the vertical structure of ozone in the lower tropical stratosphere as compared with the retrieved MLS product. We will discuss the computational efficiency of this implementation.

  10. Improving retrieval quality for airborne limb sounders by horizontal regularisation

    Directory of Open Access Journals (Sweden)

    J. Ungermann

    2013-01-01

    Full Text Available Modern airborne infrared limb sounders are capable of measuring profiles so fast that neighbouring profiles are very similar to one another. This can be exploited by retrieving whole 2-D cross-sections instead of simple 1-D profiles.

    This paper presents algorithms that are able to perform such a large-scale retrieval and that efficiently produce typical diagnostic quantities. The characteristics and capabilities of the proposed method are analysed and demonstrated in a detailed case study using a series of profiles that were measured by CRISTA-NF (Cryogenic Infrared Spectrometers and Telescope for the Atmosphere–New Frontiers.

    It is shown that cross-section retrievals can either reduce noise-induced artefacts or produce finer vertical structures while maintaining the same image noise level. Further, it is discussed how the presented methodology can also be applied to improve the retrievals for other instrument types including current satellite-borne nadir-sounders and near-future satellite-borne limb sounders.

  11. Validation of Aura Microwave Limb Sounder HCl measurements

    OpenAIRE

    L. Froidevaux; Jiang, Y.B.; Lambert, A.; Livesey, N.J.; Read, W. G.; Waters, J. W.; Fuller, R. A.; Marcy, T. P.; Popp, P. J.; R. S. Gao; Fahey, D. W.; Jucks, K. W.; Stachnik, R. A.; Toon, G. C.; Christensen, L. E.

    2008-01-01

    The Earth Observing System (EOS) Microwave Limb Sounder (MLS) aboard the Aura satellite has provided daily global HCl profiles since August 2004. We provide a characterization of the resolution, random and systematic uncertainties, and known issues for the version 2.2 MLS HCl data. The MLS sampling allows for comparisons with many (similar to 1500 to more than 3000) closely matched profiles from the Halogen Occultation Experiment (HALOE) and Atmospheric Chemistry Experiment Fourier Transform ...

  12. Cosmic ray modulation of infra-red radiation in the atmosphere

    CERN Document Server

    Aplin, K L

    2012-01-01

    Cosmic rays produce charged molecular clusters by ionisation as they pass through the lower atmosphere. Neutral molecular clusters such as dimers and complexes are expected to make a small contribution to the radiative balance, but atmospheric absorption by charged clusters has not hitherto been observed. In an atmospheric experiment, a filter radiometer tuned to the 9.15 um absorption band associated with infra-red absorption of charged molecular clusters was used to monitor changes immediately following events identified by a cosmic ray telescope sensitive to high energy (>400MeV) particles, principally muons. The change in longwave radiation in this absorption band due to charged molecular clusters is 7 mW^m-2. The integrated atmospheric energy change for each event is 2J, representing an amplification factor of 10^10 compared to the 2GeV energy of a typical tropospheric cosmic ray. This absorption is expected to occur continuously and globally.

  13. DISTRIBUTION OF CO2 IN SATURN'S ATMOSPHERE FROM CASSINI/CIRS INFRARED OBSERVATIONS

    International Nuclear Information System (INIS)

    This paper focuses on the CO2 distribution in Saturn's atmosphere based on analysis of infrared spectral observations of Saturn made by the Composite Infrared Spectrometer aboard the Cassini spacecraft. The Cassini spacecraft was launched in 1997 October, inserted in Saturn's orbit in 2004 July, and has been successfully making infrared observations of Saturn, its rings, Titan, and other icy satellites during well-planned orbital tours. The infrared observations, made with a dual Fourier transform spectrometer in both nadir- and limb-viewing modes, cover spectral regions of 10-1400 cm–1, with the option of variable apodized spectral resolutions from 0.53 to 15 cm–1. An analysis of the observed spectra with well-developed radiative transfer models and spectral inversion techniques has the potential to provide knowledge of Saturn's thermal structure and composition with global distributions of a series of gases. In this paper, we present an analysis of a large observational data set for retrieval of Saturn's CO2 distribution utilizing spectral features of CO2 in the Q-branch of the ν2 band, and discuss its possible relationship to the influx of interstellar dust grains. With limited spectral regions available for analysis, due to low densities of CO2 and interference from other gases, the retrieved CO2 profile is obtained as a function of a model photochemical profile, with the retrieved values at atmospheric pressures in the region of ∼1-10 mbar levels. The retrieved CO2 profile is found to be in good agreement with the model profile based on Infrared Space Observatory measurements with mixing ratios of ∼4.9 × 10–10 at atmospheric pressures of ∼1 mbar

  14. High spectral resolution observations of Martian atmosphere in infrared - submillimeter range from ground-based instruments.

    Science.gov (United States)

    Nakagawa, Hiromu; Kasaba, Yasumasa; Aoki, Shohei; Murata, Isao; Maezawa, Hiroyuki; Okano, Shoichi; Sagawa, Hideo; Kasai, Yasuko

    2010-05-01

    With increased knowledge on our "neighbor" planets Mars and Venus, based on recent aggressive explorations by the US and Europe, our image on them is changing significantly. In particular, Mars is called ‘a frozen water planet'. It is almost certain that Mars once had duration with warm and wet climate [Head et al., 1999; Donahue, 1995; Parker et al., 1993]. It still conserves a large amount of water ice under the surface [Boynton et al., 2002; Mitrofanov et al., 2002; Feldman et al., 2002]. The question "Why and when did they diverge?" is essential for their environments which potentially could create and keep the life or not. Many molecules in planetary atmospheres show transitions in the mid infrared - submillimeter region. Thus, high-resolution spectroscopy in this region is significantly indispensable to study planetary atmospheres. We searched sulfur oxide (SO2 and SO) in the Martian atmosphere by the Atacama Submillimeter Telescope Experiment (ASTE). Sulfur oxide is one of the most evident species in terrestrial volcanic gases. Although it has not yet been detected at Mars, this detection can constraint the Martian crustal and volcanic activities. We observed northern winter of Mars on 26/Dec./2007 (Ls=8.1) in 346 GHz range with ~ 1h integration, and got the upper limit of the SO2 mixing ratio, 2 ppb. We concluded that the crustal or volcanic gas produced into the atmosphere is tenuous in northern winter [Nakagawa et al., 2009]. Infrared heterodyne spectroscopy has proven to be a powerful tool for astrophysical studies. To achieve highest spectral resolution and sensitivity as well as compact instrumentation heterodyne systems are advantageous over direct-detection methods. Our group in Tohoku University has developed own heterodyne system for infrared spectrometer for Earth's atmosphere over the past 20 years. The failure of earlier attempts to build tunable systems using tunable diode lasers was due mostly to insufficient laser power. Recently, quantum

  15. Sound velocity from inverted echo sounders (IES) in the western Pacific Ocean from 19920826 to 19930322 (NODC Accession 9300159)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains inverted echo sounder data collected from two stations in the western Pacific, TPW nominally @ 2S and 154E and TPE nominally @ 2S and 164E....

  16. Nimbus-6 High Resolution Infrared Radiometer (HIRS) Level 1 Calibrated Radiances for the Global Atmospheric Research Program (GARP) V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The Nimbus-6 High Resolution Infrared Radiometer (HIRS) Level 1 Calibrated Radiances for the Global Atmospheric Research Program (GARP) data product contains daily...

  17. A synthetic data set of high-spectral-resolution infrared spectra for the Arctic atmosphere

    Science.gov (United States)

    Cox, Christopher J.; Rowe, Penny M.; Neshyba, Steven P.; Walden, Von P.

    2016-05-01

    Cloud microphysical and macrophysical properties are critical for understanding the role of clouds in climate. These properties are commonly retrieved from ground-based and satellite-based infrared remote sensing instruments. However, retrieval uncertainties are difficult to quantify without a standard for comparison. This is particularly true over the polar regions, where surface-based data for a cloud climatology are sparse, yet clouds represent a major source of uncertainty in weather and climate models. We describe a synthetic high-spectral-resolution infrared data set that is designed to facilitate validation and development of cloud retrieval algorithms for surface- and satellite-based remote sensing instruments. Since the data set is calculated using pre-defined cloudy atmospheres, the properties of the cloud and atmospheric state are known a priori. The atmospheric state used for the simulations is drawn from radiosonde measurements made at the North Slope of Alaska (NSA) Atmospheric Radiation Measurement (ARM) site at Barrow, Alaska (71.325° N, 156.615° W), a location that is generally representative of the western Arctic. The cloud properties for each simulation are selected from statistical distributions derived from past field measurements. Upwelling (at 60 km) and downwelling (at the surface) infrared spectra are simulated for 260 cloudy cases from 50 to 3000 cm-1 (3.3 to 200 µm) at monochromatic (line-by-line) resolution at a spacing of ˜ 0.01 cm-1 using the Line-by-line Radiative Transfer Model (LBLRTM) and the discrete-ordinate-method radiative transfer code (DISORT). These spectra are freely available for interested researchers from the NSF Arctic Data Center data repository (http://dx.doi.org/10.5065/D61J97TT" target="_blank">doi:10.5065/D61J97TT).

  18. Atmospheric ultraviolet and red-infrared flashes from Universitetsky-Tatiana-2 satellite data

    International Nuclear Information System (INIS)

    Millisecond ultraviolet (240–400 nm) and red-infrared (610–800 nm) flashes were detected in the nighttime atmosphere with the scientific payload installed onboard the Universitetsky-Tatiana-2 micro-satellite. Flashes with various numbers of photons, from 1020 to 1026, were detected within the atmospheric area 300 km in diameter observed by the detector. The flashes differ in duration and temporal profile: from single short flashes ∼1 ms in duration to flashes with a complex profile more than 100 ms in duration. Different global geographic distributions are observed for flashes with different numbers of photons. Flashes with fewer than 1022 photons are distributed uniformly over the Earth’s map. Flashes with more than 1022 photons are concentrated near the equator and above the continents. Series of flashes were observed in one turn of the satellite when flying not only over thunderstorm regions but also over cloudless ones. The flash number distribution has been derived from the ratio of the numbers of red-infrared and ultraviolet photons. As applied to discharges in the upper atmosphere, whose glow is dominated by the emission in the first and second positive systems of molecular nitrogen bands (1PN2 and 2PN2), this distribution is equivalent to the flash altitude distribution in the atmosphere. The observed ratio of the numbers of photons in red-infrared and ultraviolet flashes agrees with the calculated one for electric discharges at altitudes higher than 50 km. In-orbit measurements of the charged particle flux (with a threshold energy for electrons of 1 MeV) provide no evidence for a synchronous occurrence of an ultraviolet flash and a burst in the particle flux in the orbit.

  19. Dispersive infrared spectroscopy measurements of atmospheric CO2 using a Fabry–Pérot interferometer sensor

    International Nuclear Information System (INIS)

    In this paper, we present the first dispersive infrared spectroscopic (DIRS) measurement of atmospheric carbon dioxide (CO2) using a new scanning Fabry–Pérot interferometer (FPI) sensor. The sensor measures the optical spectra in the mid infrared (3900 nm to 5220 nm) wavelength range with full width half maximum (FWHM) spectral resolution of 78.8 nm at the CO2 absorption band (∼ 4280 nm) and sampling resolution of 20 nm. The CO2 concentration is determined from the measured optical absorption spectra by fitting it to the CO2 reference spectrum. Interference from other major absorbers in the same wavelength range, e.g., carbon monoxide (CO) and water vapor (H2O), was taken out by including their reference spectra in the fit as well. The detailed descriptions of the instrumental setup, the retrieval procedure, a modeling study for error analysis as well as laboratory validation using standard gas concentrations are presented. An iterative algorithm to account for the non-linear response of the fit function to the absorption cross sections due to the broad instrument function was developed and tested. A modeling study of the retrieval algorithm showed that errors due to instrument noise can be considerably reduced by using the dispersive spectral information in the retrieval. The mean measurement error of the prototype DIRS CO2 measurement for 1 minute averaged data is about ± 2.5 ppmv, and down to ± 0.8 ppmv for 10 minute averaged data. A field test of atmospheric CO2 measurements were carried out in an urban site in Hong Kong for a month and compared to a commercial non-dispersive infrared (NDIR) CO2 analyzer. 10 minute averaged data shows good agreement between the DIRS and NDIR measurements with Pearson correlation coefficient (R) of 0.99. This new method offers an alternative approach of atmospheric CO2 measurement featuring high accuracy, correction of non-linear absorption and interference of water vapor. - Highlights: • Dispersive infrared

  20. Herbig Stars' Near-Infrared Excess: An Origin in the Protostellar Disk's Magnetically-Supported Atmosphere

    CERN Document Server

    Turner, N J; Dullemond, C P; Hirose, S

    2013-01-01

    Young stars with masses 2-8 Suns, called the Herbig Ae and Be stars, often show a near-infrared excess too large to explain with a hydrostatically-supported circumstellar disk of gas and dust. At the same time the accretion flow carrying the circumstellar gas to the star is thought to be driven by magneto-rotational turbulence, which according to numerical MHD modeling yields an extended low-density atmosphere supported by the magnetic fields. We demonstrate that the base of the atmosphere can be optically-thick to the starlight and that the parts lying near 1 AU are tall enough to double the fraction of the stellar luminosity reprocessed into the near-infrared. We generate synthetic spectral energy distributions (SEDs) using Monte Carlo radiative transfer calculations with opacities for sub-micron silicate and carbonaceous grains. The synthetic SEDs closely follow the median Herbig SED constructed recently by Mulders and Dominik, and in particular match the large near-infrared flux, provided the grains have ...

  1. Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, G. [Laboratoire d' Ingenierie de Surface, Centre de Recherche sur les Materiaux Avances, Departement de genie des mines, de la metallurgie et des materiaux, Universite Laval, 1065, avenue de la Medecine, Quebec G1V 0A6 (Canada); Centre de recherche du CHUQ, Hopital St Francois d' Assise, 10, rue de l' Espinay, local E0-165, Quebec G1L 3L5 (Canada); Vallade, J. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Agence de l' environnement et de la Ma Latin-Small-Letter-Dotless-I -carettrise de l' Energie, 20, avenue du Gresille, BP 90406, F-49004 Angers Cedex 01 (France); Bazinette, R.; Hernandez, E.; Hernandez, G.; Massines, F. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Nijnatten, P. van [OMT Solutions bv, High Tech Campus 9, 5656AE Eindhoven (Netherlands)

    2012-10-15

    This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm Multiplication-Sign 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45 Degree-Sign beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

  2. Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution

    International Nuclear Information System (INIS)

    This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm × 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45° beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

  3. Quantitative infrared absorption cross-sections of isoprene for atmospheric measurements

    Directory of Open Access Journals (Sweden)

    C. S. Brauer

    2014-04-01

    Full Text Available Isoprene (C5H8, 2-methyl-1,3-butadiene is a volatile organic compound (VOC that is one of the primary contributors to annual global VOC emissions. Produced by vegetation as well as anthropogenic sources, the OH- and O3-initiated oxidations of isoprene are a major source of atmospheric oxygenated organics. Few quantitative infrared studies have been reported for isoprene, however, limiting the ability to quantify isoprene emissions via stand-off infrared or in situ detection. We thus report absorption coefficients and integrated band intensities for isoprene in the 600–6500 cm−1 region. The pressure-broadened (1 atmosphere N2 spectra were recorded at 278, 298 and 323 K in a 19.94 cm path length cell at 0.112 cm−1 resolution, using a Bruker 66v FTIR. Composite spectra are derived from a minimum of seven isoprene sample pressures at each temperature and the number densities are normalized to 296 K and 1 atmosphere.

  4. Intercontinental transport of anthropogenic sulfur dioxide and other pollutants: An infrared remote sensing case study

    OpenAIRE

    Clarisse, Lieven; Fromm, Michael; Ngadi, Yasmine; Emmons, Louisa; Clerbaux, Cathy; Hurtmans, Daniel; Coheur, Pierre-François

    2011-01-01

    International audience Using 3 years worth of IASI (the Infrared Atmospheric Sounder Interferometer aboard METOP-A) measurements, we have identified 24 major events of uplift and transport of anthropogenic sulfur dioxide. These were all first observed over East Asia, and could be traced for over 60 hours. On 7 November 2010 a sulfur dioxide plume was observed over Northeast China and tracked for five days to North America. We discuss this event in detail with respect to build up; uplift an...

  5. Atmospheric correction of MODIS thermal infrared bands by water vapor scaling method

    Science.gov (United States)

    Tonooka, Hideyuki

    2005-10-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) project has operationally provided land surface temperature (LST) and emissivity imagery produced from mid-infrared bands by either of two atmospheric correction algorithms. One is the generalized split-window algorithm. This algorithm can be applied to each observed scene, and the spatial resolution of generated products is 1 km, but the emissivity data in the products are empirically estimated by a classification-based method. Another is the physics-based day/night algorithm. In this algorithm, both LST and emissivity are physically determined using mid-infrared measurements, but a pair of day/night scenes is necessary for each processing, and the spectral resolution of generated products is degraded to 5 km. In the present paper, the water vapor scaling (WVS) method (Tonooka, 2001 and 2005) is applied to three MODIS thermal infrared (TIR) bands (29, 31, and 32) as an alternative approach. This method is an atmospheric correction algorithm for TIR multi-spectral data including land surfaces, designed mainly for the five TIR spectral bands of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on the Terra satellite. The WVS method is on the basis of a traditional approach using a radiative transfer code, such as MODTRAN, combined with external atmospheric profiles, but the errors included in profiles are reduced on a pixel-by-pixel basis using an extended multi-channel approach. In the present paper, the WVS method for the three MODIS TIR bands is proposed, and applied to actual imagery for preliminary validation.

  6. A Useful Tool for Atmospheric Correction and Surface Temperature Estimation of Landsat Infrared Thermal Data

    Science.gov (United States)

    Rivalland, Vincent; Tardy, Benjamin; Huc, Mireille; Hagolle, Olivier; Marcq, Sébastien; Boulet, Gilles

    2016-04-01

    Land Surface temperature (LST) is a critical variable for studying the energy and water budgets at the Earth surface, and is a key component of many aspects of climate research and services. The Landsat program jointly carried out by NASA and USGS has been providing thermal infrared data for 40 years, but no associated LST product has been yet routinely proposed to community. To derive LST values, radiances measured at sensor-level need to be corrected for the atmospheric absorption, the atmospheric emission and the surface emissivity effect. Until now, existing LST products have been generated with multi channel methods such as the Temperature/Emissivity Separation (TES) adapted to ASTER data or the generalized split-window algorithm adapted to MODIS multispectral data. Those approaches are ill-adapted to the Landsat mono-window data specificity. The atmospheric correction methodology usually used for Landsat data requires detailed information about the state of the atmosphere. This information may be obtained from radio-sounding or model atmospheric reanalysis and is supplied to a radiative transfer model in order to estimate atmospheric parameters for a given coordinate. In this work, we present a new automatic tool dedicated to Landsat thermal data correction which improves the common atmospheric correction methodology by introducing the spatial dimension in the process. The python tool developed during this study, named LANDARTs for LANDsat Automatic Retrieval of surface Temperature, is fully automatic and provides atmospheric corrections for a whole Landsat tile. Vertical atmospheric conditions are downloaded from the ERA Interim dataset from ECMWF meteorological organization which provides them at 0.125 degrees resolution, at a global scale and with a 6-hour-time step. The atmospheric correction parameters are estimated on the atmospheric grid using the commercial software MODTRAN, then interpolated to 30m resolution. We detail the processing steps

  7. Infrared

    Science.gov (United States)

    Vollmer, M.

    2013-11-01

    techniques such as attenuated total reflectance [6]. The two final papers deal with what seem to be wholly different scientific fields [7, 8]. One paper describes SOFIA, an aeroplane-based astronomical observatory covering the whole IR range [7], while the other represents a small review of the quite new topic of terahertz physics at the upper end of the IR spectral range, from around 30 µm to 3 mm wavelength, and its many applications in science and industry [8]. Although artificially separated, all these fields use similar kinds of detectors, similar kinds of IR sources and similar technologies, while the instruments use the same physical principles. We are convinced that the field of infrared physics will develop over the next decade in the same dynamic way as during the last, and this special issue may serve as starting point for regular submissions on the topic. At any rate, it shines a light on this fascinating and many-faceted subject, which started more than 200 years ago. References [1] Mangold K, Shaw J A and Vollmer M 2013 The physics of near-infrared photography Eur. J. Phys. 34 S51-71 [2] Vollmer M and Möllmann K-P 2013 Characterization of IR cameras in student labs Eur. J. Phys. 34 S73-90 [3] Ibarra-Castanedo C, Tarpani J R and Maldague X P V 2013 Nondestructive testing with thermography Eur. J. Phys. 34 S91-109 [4] Shaw J A and Nugent P W 2013 Physics principles in radiometric infrared imaging of clouds in the atmosphere Eur. J. Phys. 34 S111-21 [5] Möllmann K-P and Vollmer M 2013 Fourier transform infrared spectroscopy in physics laboratory courses Eur. J. Phys. 34 S123-37 [6] Heise H M, Fritzsche J, Tkatsch H, Waag F, Karch K, Henze K, Delbeck S and Budde J 2013 Recent advances in mid- and near-infrared spectroscopy with applications for research and teaching, focusing on petrochemistry and biotechnology relevant products Eur. J. Phys. 34 S139-59 [7] Krabbe A, Mehlert D, Röser H-P and Scorza C 2013 SOFIA, an airborne observatory for infrared astronomy

  8. Spectral Irradiance Calibration in the Infrared. Part 7; New Composite Spectra, Comparison with Model Atmospheres, and Far-Infrared Extrapolations

    Science.gov (United States)

    Cohen, Martin; Witteborn, Fred C.; Carbon, Duane F.; Davies, John K.; Wooden, Diane H.; Bregman, Jesse D.

    1996-01-01

    We present five new absolutely calibrated continuous stellar spectra constructed as far as possible from spectral fragments observed from the ground, the Kuiper Airborne Observatory (KAO), and the IRAS Low Resolution Spectrometer. These stars-alpha Boo, gamma Dra, alpha Cet, gamma Cru, and mu UMa-augment our six, published, absolutely calibrated spectra of K and early-M giants. All spectra have a common calibration pedigree. A revised composite for alpha Boo has been constructed from higher quality spectral fragments than our previously published one. The spectrum of gamma Dra was created in direct response to the needs of instruments aboard the Infrared Space Observatory (ISO); this star's location near the north ecliptic pole renders it highly visible throughout the mission. We compare all our low-resolution composite spectra with Kurucz model atmospheres and find good agreement in shape, with the obvious exception of the SiO fundamental, still lacking in current grids of model atmospheres. The CO fundamental seems slightly too deep in these models, but this could reflect our use of generic models with solar metal abundances rather than models specific to the metallicities of the individual stars. Angular diameters derived from these spectra and models are in excellent agreement with the best observed diameters. The ratio of our adopted Sirius and Vega models is vindicated by spectral observations. We compare IRAS fluxes predicted from our cool stellar spectra with those observed and conclude that, at 12 and 25 microns, flux densities measured by IRAS should be revised downwards by about 4.1% and 5.7%, respectively, for consistency with our absolute calibration. We have provided extrapolated continuum versions of these spectra to 300 microns, in direct support of ISO (PHT and LWS instruments). These spectra are consistent with IRAS flux densities at 60 and 100 microns.

  9. Theoretical model atmosphere spectra used for the calibration of infrared instruments

    CERN Document Server

    Decin, L

    2007-01-01

    One of the key ingredients in establishing the relation between input signal and output flux from a spectrometer is accurate determination of the spectrophotometric calibration. In the case of spectrometers onboard satellites, the accuracy of this part of the calibration pedigree is ultimately linked to the accuracy of the set of reference SEDs that the spectrophotometric calibration is built on. In this paper, we deal with the spectrophotometric calibration of infrared (IR) spectrometers onboard satellites in the 2 to 200 micron range. We aim at comparing the different reference SEDs used for the IR spectrophotometric calibration. The emphasis is on the reference SEDs of stellar standards with spectral type later than A0, with special focus on the theoretical model atmosphere spectra. Using the MARCS model atmosphere code, spectral reference SEDs were constructed for a set of IR stellar standards (A dwarfs, solar analogs, G9-M0 giants). A detailed error analysis was performed to estimate proper uncertainties...

  10. Temperature Profile and Surface Pressure Retrieval of Mars’ Atmosphere Using Infrared Heterodyne Spectroscopy

    Science.gov (United States)

    Smith, Ramsey L.; Hewagama, T.; Livengood, T. A.; Fast, K. E.; Kostiuk, T.

    2012-10-01

    Infrared heterodyne spectroscopy of CO2 transitions in the Martian atmosphere was obtained using the Goddard Space Flight Center’s Heterodyne Instrument for Planetary Winds and Composition, HIPWAC, on the NASA Infrared Telescope Facility 3-m telescope, with resolving power of 2.5107. The measured spectra are not fully consistent with temperature profiles for this location and season derived from the Mars Global Surveyor mission (MGS), particularly constraining the pressure and temperature in the deepest part of the troposphere with unambiguous differences between the MGS temperature profile and that required to satisfy the measured emergent spectrum. The temperature information is useful for studying seasonal and global variability, for comparison of results from flight mission results, as well as better profiles for interpreting flight obtained measurements. We will report data collected from our analysis of our high-resolution measurement of 16O12C16O used to develop a temperature profile and surface pressure. CO2 is uniformly mixed in the Martian atmosphere, which makes it an ideal candidate for temperature determination. We are able to collect spectra of the isotopologues of CO2 in the same spectra, which eliminates a source of error for molecular species identification and atmosphere temperature determination. The aforementioned parameters are critical for Martian atmospheric-surface investigations such as isotopologue determination and isotope ratio calculations. For example, an average over measurements acquired at the subsolar point and in the early afternoon at the subsolar latitude yields the terrestrial VSMOW standard, with a minimal difference of 18O = +9±14 ‰. This precision is sufficient to enable a remote investigation of seasonal variations, i.e. due to mass-dependent fractionation in the polar ice cap freeze-sublimate cycle.

  11. Atmospheric correction of thermal-infrared imagery of the 3-D urban environment acquired in oblique viewing geometry

    OpenAIRE

    F. Meier; D. Scherer; Richters, J.; A. Christen

    2010-01-01

    This research quantifies and discusses atmospheric effects that alter the radiance observed by a ground-based thermal-infrared (TIR) camera mounted on top of a high-rise building in the city of Berlin, Germany. The study shows that atmospheric correction of ground-based TIR imagery of the three-dimensional (3-D) urban environment acquired in oblique viewing geometry has to account for spatial variability of line-of-sight (LOS) geometry. We present an atmospheric correction procedure t...

  12. Absorption of infra-red radiation by atmospheric molecular cluster-ions

    CERN Document Server

    Aplin, K L

    2005-01-01

    Protonated water clusters are a common species of atmospheric molecular cluster-ion, produced by cosmic rays throughout the troposphere and stratosphere. Under clear-sky conditions or periods of increased atmospheric ionisation, such as solar proton events, the IR absorption by atmospheric ions may affect climate through the radiative balance. Fourier Transform Infrared Spectrometry in a long path cell, of path length 545m, has been used to detect IR absorption by corona-generated positive molecular cluster-ions. The column concentration of ions in the laboratory spectroscopy experiment was estimated to be ~10^13 m-2; the column concentration of protonated atmospheric ions estimated using a simple model is ~10^14 m-2. Two regions of absorption, at 12.3 and 9.1 um are associated with enhanced ion concentrations. After filtering of the measured spectra to compensate for spurious signals from neutral water vapour and residual carbon dioxide, the strongest absorption region is at 9.5 to 8.8 um (1050 to 1140 cm-1)...

  13. Cosmic ray modulation of infra-red radiation in the atmosphere

    International Nuclear Information System (INIS)

    Cosmic rays produce molecular cluster ions as they pass through the lower atmosphere. Neutral molecular clusters such as dimers and complexes are expected to make a small contribution to the radiative balance, but atmospheric absorption by charged clusters has not hitherto been observed. In an atmospheric experiment, a narrowband thermopile filter radiometer centred on 9.15 μm, an absorption band previously associated with infra-red absorption of molecular cluster ions, was used to monitor changes following events identified by a cosmic ray telescope sensitive to high-energy (>400 MeV) particles, principally muons. The average change in longwave radiation in this absorption band due to molecular cluster ions is 7 mWm−2. The integrated atmospheric energy density for each event is 2 Jm−2, representing an amplification factor of 1012 compared to the estimated energy density of a typical air shower. This absorption is expected to occur continuously and globally, but calculations suggest that it has only a small effect on climate. (letter)

  14. Atmospheric transmittance of an absorbing gas. 7. Further improvements to the OPTRAN 6 approach

    Science.gov (United States)

    McMillin, Larry M.; Xiong, Xiaozhen; Han, Yong; Kleespies, Thomas J.; van Delst, Paul

    2006-03-01

    We present recent improvements in accuracy to the fast transmittance-calculation procedure, Optical Path Transmittance (OPTRAN), which is used for satellite data assimilation at the National Oceanic and Atmospheric Administration. These improvements are (1) to change the absorber space used for ozone, (2) to add new predictors for each gas, and (3) to treat the water vapor line absorption and water continuum absorption as separate terms. Significant improvements in the accuracy of the OPTRAN algorithm for High-Resolution Infrared Radiation Sounders (HIRS) and the Atmospheric Infrared Sounder (AIRS) are demonstrated. The results that we show here extend a recent paper of Xiong and McMillin (2004) that describes the use of a polychromatic correction term to replace the effective transmittance concept to include additional changes that improve accuracy.

  15. Heterogeneous doped one-dimensional photonic crystal with low emissivity in infrared atmospheric window

    Science.gov (United States)

    Miao, Lei; Shi, Jiaming; Wang, Jiachun; Zhao, Dapeng; Chen, Zongsheng; Wang, Qichao

    2016-05-01

    The characteristic matrix method in thin-film optical theory was used to calculate heterogeneous doped one-dimensional photonic crystals (1-D PCs), which were fabricated by alternate deposition of Te, ZnSe, and Si materials on a silicon wafer. The heterogeneous structure was adopted to broaden the photonic band gap, within which the low reflection valley was achieved by doping. Infrared spectrum tests showed that the average emissivities of the 1-D PC were 0.0845 and 0.281, corresponding, respectively, to the bands of 3 to 5 and 8 to 14 μm. Moreover, the emissivity was 0.45 over the 5 to 8 μm nonatmospheric window, and the reflectivity was 0.28 at the wavelength of 10.6 μm. The results indicated that the heterogeneous doped 1-D PC was able to selectively achieve low emissivities over infrared atmospheric windows and a low reflectivity for the CO2 laser, which exhibited remarkable competence in compatible infrared and laser stealth applications.

  16. Quantitative study of a gaseous atmosphere by Fourier transformation infrared spectroscopy (FTIR)

    International Nuclear Information System (INIS)

    The aim of this work is to implement an in situ quantitative analysis of gases present in a gaseous atmosphere by Fourier transformation infrared spectroscopy in order to determine the processes occurring during the uranium corrosion reactions. Indeed, during these reactions, the gaseous atmosphere initially present evolves during the reaction and leads to the formation of new gaseous species. The aim is then to in situ quantify the proportion of species present during all the reactional process. A preliminary study on pure gases has been carried out. The studied gases are: CH4, CO2, H2 and CO. The aim is to identify their spectral symbol in the infrared and to determine their behaviour (absorbance) in terms of their concentration. The study of different binary gases mixtures, as for instance CO2/H2, CH4/H2, CO/H2 or CH4/CO2 has been carried out too. This study presents the results concerning the CO2/H2 mixture and more particularly the evolution of the spectral sign of gases in terms of the partial concentrations of H2 and CO2. The study of the spectra of this mixtures show that the presence of a gaseous specie has an influence on the characteristics of the peaks (intensity and area) of the spectra relative to other gaseous species present in the mixture according to a transfer function which has then been determined. The feasibility of the implementation of an in situ quantitative gaseous analysis by Fourier transformation infrared spectroscopy is then discussed from FTIR tables (intensity and area of peaks) obtained on gaseous mixtures. (O.M.)

  17. Retrieval of atmospheric parameters and radiative properties using Far-Infrared remote sensing measurements

    Science.gov (United States)

    Jamali, Maryam; Milz, Mathias; Martín-Torres, Javier; Palchetti, Luca

    2016-04-01

    The far-infrared (FIR) spectral region, covering wavelengths between 15 μm (667 cm‑1) and about 1 μm (10,000 cm‑1) plays a critical role in the climate system. A good knowledge of the radiation processes in this spectral region is of high interest for observations and understanding of heating and cooling rates, and global energy balance. Even though approximately 50% of terrestrial radiation occurs in the FIR and despite the critical FIR contribution to the Earth's energy balance, this spectral region has been only studied by a few number of instruments. Also the full FIR spectral region has not ever been directly observed from space. High spectral resolution observations in this region can help to enlighten its role for the global energy budget and atmospheric radiation processes. Among others, the reasons for this lack of measurements are: (i) the decreasing intensity of the radiation towards longer wavelengths; and, then (ii) the high sensitivity and cooling of the detectors requirements. These requirements are now overcome and future space missions will have the capability to measure the full FIR and then open fully one-half of the Earth's spectrum, and accordingly improve our ability to model and assess climate processes. The aim of the study is to assess the use of FIR remote sensing instruments for retrievals of atmospheric parameters and radiative properties such as heating and cooling rates. Case studies with simulated spectra, together with ground based measurements in the FIR at Dome C over the Antarctic Plateau at 3,230 m a.s.l. (above sea level) in clear-sky conditions, which been observed almost continuously since 2012, are used to assess the potential of remote sensing instruments in the far-infrared region. Appropriate selection of spectral channels to directly measure the far-infrared spectra as needed for future space missions and recommended.

  18. Retrieval of volcanic ash properties from the Infrared Atmospheric Sounding Interferometer (IASI)

    Science.gov (United States)

    Ventress, Lucy; Carboni, Elisa; Smith, Andrew; Grainger, Don; Dudhia, Anu; Hayer, Catherine

    2014-05-01

    The Infrared Atmospheric Sounding Interferometer (IASI), on board both the MetOp-A and MetOp-B platforms, is a Fourier transform spectrometer covering the mid-infrared (IR) from 645-2760cm-1 (3.62-15.5 μm) with a spectral resolution of 0.5cm-1 (apodised) and a pixel diameter at nadir of 12km. These characteristics allow global coverage to be achieved twice daily for each instrument and make IASI a very useful tool for the observation of larger aerosol particles (such as desert dust and volcanic ash) and the tracking of volcanic plumes. In recent years, following the eruption of Eyjafjallajökull, interest in the the ability to detect and characterise volcanic ash plumes has peaked due to the hazards to aviation. The thermal infrared spectra shows a rapid variation with wavelength due to absorption lines from atmospheric and volcanic gases as well as broad scale features principally due to particulate absorption. The ash signature depends upon both the composition and size distribution of ash particles as well as the altitude of the volcanic plume. To retrieve ash properties, IASI brightness temperature spectra are analysed using an optimal estimation retrieval scheme and a forward model based on RTTOV. Initially, IASI pixels are flagged for the presence of volcanic ash using a linear retrieval detection method based on departures from a background state. Given a positive ash signal, the RTTOV output for a clean atmosphere (containing atmospheric gases but no cloud or aerosol/ash) is combined with an ash/cloud layer using the same scheme as for the Oxford-RAL Retrieval of Aerosol and Cloud (ORAC) algorithm. The retrieved parameters are ash optical depth (at a reference wavelength of 550nm), ash effective radius, layer altitude and surface temperature. The potential for distinguishing between different ash types is explored and a sensitivity study of the retrieval algorithm is presented. Results are shown from studies of the evolution and composition of ash plumes

  19. Infrared measurements in the Arctic using two Atmospheric Emitted Radiance Interferometers

    Directory of Open Access Journals (Sweden)

    Z. Mariani

    2012-02-01

    Full Text Available The Extended-range Atmospheric Emitted Radiance Interferometer (E-AERI is a moderate resolution (1 cm−1 Fourier transform infrared spectrometer for measuring the absolute downwelling infrared spectral radiance from the atmosphere between 400 and 3000 cm−1. The extended spectral range of the instrument permits monitoring of the 400–550 cm−1 (20–25 μm region, where most of the infrared surface cooling currently occurs in the dry air of the Arctic. Spectra from the E-AERI have the potential to provide information about radiative balance, trace gases, and cloud properties in the Canadian high Arctic. Calibration, performance evaluation, and certification of the E-AERI were performed at the University of Wisconsin Space Science and Engineering Centre from September to October 2008. The instrument was then installed at the Polar Environment Atmospheric Research Laboratory (PEARL Ridge Lab (610 m altitude at Eureka, Nunavut, in October 2008, where it acquired one year of data. Measurements are taken every seven minutes year-round, including polar night when the solar-viewing spectrometers at PEARL are not operated. A similar instrument, the University of Idaho's Polar AERI (P-AERI, was installed at the Zero-altitude PEARL Auxiliary Laboratory (0PAL, 15 km away from the PEARL Ridge Lab, from March 2006 to June 2009. During the period of overlap, these two instruments provided calibrated radiance measurements from two altitudes. A fast line-by-line radiative transfer model is used to simulate the downwelling radiance at both altitudes; the largest differences (simulation-measurement occur in spectral regions strongly influenced by atmospheric temperature and/or water vapour. The two AERI instruments at close proximity but located at two different altitudes are well-suited for investigating cloud forcing. As an example, it is shown that a thin, low ice cloud resulted in a 6% increase in irradiance. The presence

  20. Atmospheric effects on infrared measurements at ground level: Application to monitoring of transport infrastructures

    Science.gov (United States)

    Boucher, Vincent; Dumoulin, Jean

    2014-05-01

    Being able to perform easily non-invasive diagnostics for surveillance and monitoring of critical transport infrastructures is a major preoccupation of many technical offices. Among all the existing electromagnetic methods [1], long term thermal monitoring by uncooled infrared camera [2] is a promising technique due to its dissemination potential according to its low cost on the market. Nevertheless, Knowledge of environmental parameters during measurement in outdoor applications is required to carry out accurate measurement corrections induced by atmospheric effects at ground level. Particularly considering atmospheric effects and measurements in foggy conditions close as possible to those that can be encountered around transport infrastructures, both in visible and infrared spectra. In the present study, atmospheric effects are first addressed by using data base available in literature and modelling. Atmospheric attenuation by particles depends greatly of aerosols density, but when relative humidity increases, water vapor condenses onto the particulates suspended in the atmosphere. This condensed water increases the size of the aerosols and changes their composition and their effective refractive index. The resulting effect of the aerosols on the absorption and scattering of radiation will correspondingly be modified. In a first approach, we used aerosols size distributions derived from Shettle and Fenn [3] for urban area which could match some of experimental conditions encountered during trials on transport infrastructures opened to traffic. In order to calculate the influence of relative humidity on refractive index, the Hänel's model [4] could be used. The change in the particulate size is first related to relative humidity through dry particle radius, particle density and water activity. Once the wet aerosol particle size is found, the effective complex refractive index is the volume weighted average of the refractive indexes of the dry aerosol substance

  1. Synergy between middle infrared and millimeter-wave limb sounding of atmospheric temperature and minor constituents

    Science.gov (United States)

    Cortesi, Ugo; Del Bianco, Samuele; Ceccherini, Simone; Gai, Marco; Dinelli, Bianca Maria; Castelli, Elisa; Oelhaf, Hermann; Woiwode, Wolfgang; Höpfner, Michael; Gerber, Daniel

    2016-05-01

    Synergistic exploitation of redundant and complementary information from independent observations of the same target remains a major issue in atmospheric remote sounding and increasing attention is devoted to investigate optimized or innovative methods for the combination of two or more measured data sets. This paper focuses on the synergy between middle infrared and millimeter-wave limb sounding measurements of atmospheric composition and temperature and reports the results of a study conducted as part of the preparatory activities of the PREMIER (Process Exploration through Measurements of Infrared and millimeter-wave Emitted Radiation) mission candidate to the Core Missions of the European Space Agency (ESA) Earth Explorer 7. The activity was based on data acquired by the MIPAS-STR (Michelson Interferometer for Passive Atmospheric Sounding - STRatospheric aircraft) and MARSCHALS (Millimetre-wave Airborne Receivers for Spectroscopic CHaracterisation in Atmospheric Limb Sounding) instruments on-board the high-altitude research aircraft M-55 Geophysica during the flight of the PremierEx (PREMIER Experiment) campaign on 10 March 2010 from Kiruna, Sweden, for observation of the Arctic upper troposphere and lower stratosphere. The cloud coverage observed along the flight provided representative test cases to evaluate the synergy in three different scenarios: low clouds in the first part, no clouds in the central part and high tropospheric clouds at the end. The calculation of synergistic profiles of four atmospheric targets (i.e., O3, HNO3, H2O and temperature) was performed using a posteriori combination of individual retrieved profiles, i.e., Level 2 (L2) data rather than simultaneous inversion of observed radiances, i.e., Level 1 (L1) data. An innovative method of data fusion, based on the Measurement Space Solution (MSS) was applied along with the standard approach of inversion of MARSCHALS spectral radiances using MIPAS-STR retrieval products as a priori

  2. Synergy between middle infrared and millimetre-wave limb sounding of atmospheric temperature and minor constituents

    Science.gov (United States)

    Cortesi, U.; Del Bianco, S.; Ceccherini, S.; Gai, M.; Dinelli, B. M.; Castelli, E.; Oelhaf, H.; Woiwode, W.; Höpfner, M.; Gerber, D.

    2015-11-01

    Synergistic exploitation of redundant and complementary information from independent observations of the same target remains a major issue in atmospheric remote-sounding and increasing attention is devoted to investigate optimised or innovative methods for the combination of two or more measured data sets. This paper is focusing on the synergy between middle infrared and millimetre-wave limb sounding measurements of atmospheric composition and temperature and reports the results of a study conducted as part of the preparatory activities of the PREMIER (Process Exploration through Measurements of Infrared and millimetre wave Emitted Radiation) mission candidate to the Core Missions of ESA Earth Explorer 7. The activity was based on data acquired by the MIPAS-STR (Michelson Interferometer for Passive Atmospheric Sounding - STRatospheric aircraft) and MARSCHALS (Millimetre-wave Airborne Receivers for Spectroscopic CHaracterisation in Atmospheric Limb Sounding) instruments onboard the high altitude research aircraft M-55 Geophysica during the flight of the PremierEx (PREMIER Experiment) campaign on 10 March 2010 from Kiruna, Sweden for observation of the Arctic upper troposphere and lower stratosphere. The cloud coverage observed along the flight provided representative test cases to evaluate the synergy in three different scenarios: low clouds in the first part, no clouds in the central part and high tropospheric clouds at the end. The calculation of synergistic profiles of four atmospheric targets (i.e., O2, HNO3, H2O and temperature) was performed using a posteriori combination of individual retrieved profiles, i.e., Level 2 (L2) data rather than simultaneous inverse processing of observed radiances, i.e., Level 1 (L1) data. An innovative method of data fusion, based on the Measurement Space Solution (MSS) was applied along with the standard approach of inverse processing of MARSCHALS spectral radiances using MIPAS-STR retrieval products as a priori information (L1

  3. High-resolution atmospheric pressure infrared laser desorption/ionization mass spectrometry imaging of biological tissue.

    Science.gov (United States)

    Römpp, Andreas; Schäfer, Karl Christian; Guenther, Sabine; Wang, Zheng; Köstler, Martin; Leisner, Arne; Paschke, Carmen; Schramm, Thorsten; Spengler, Bernhard

    2013-09-01

    An atmospheric pressure laser desorption/ionization mass spectrometry imaging ion source has been developed that combines high spatial resolution and high mass resolution for the in situ analysis of biological tissue. The system is based on an infrared laser system working at 2.94 to 3.10 μm wavelength, employing a Nd:YAG laser-pumped optical parametrical oscillator. A Raman-shifted Nd:YAG laser system was also tested as an alternative irradiation source. A dedicated optical setup was used to focus the laser beam, coaxially with the ion optical axis and normal to the sample surface, to a spot size of 30 μm in diameter. No additional matrix was needed for laser desorption/ionization. A cooling stage was developed to reduce evaporation of physiological cell water. Ions were formed under atmospheric pressure and transferred by an extended heated capillary into the atmospheric pressure inlet of an orbital trapping mass spectrometer. Various phospholipid compounds were detected, identified, and imaged at a pixel resolution of up to 25 μm from mouse brain tissue sections. Mass accuracies of better than 2 ppm and a mass resolution of 30,000 at m/z = 400 were achieved for these measurements. PMID:23877173

  4. Py4CAtS - Python Tools for Line-by-Line Modelling of Infrared Atmospheric Radiative Transfer

    OpenAIRE

    Schreier, Franz; Gimeno Garcia, Sebastian

    2013-01-01

    Py4CAtS — Python scripts for Computational ATmospheric Spectroscopy is a Python re-implementation of the Fortran infrared radiative transfer code GARLIC, where compute-intensive code sections utilize the Numeric/Scientific Python modules for highly optimized array-processing. The individual steps of an infrared or microwave radiative transfer computation are implemented in separate scripts to extract lines of relevant molecules in the spectral range of interest, to compute line-by-line cross ...

  5. Atmospheric influences on infrared-laser signals used for occultation measurements between Low Earth Orbit satellites

    Science.gov (United States)

    Schweitzer, S.; Kirchengast, G.; Proschek, V.

    2011-10-01

    LEO-LEO infrared-laser occultation (LIO) is a new occultation technique between Low Earth Orbit (LEO) satellites, which applies signals in the short wave infrared spectral range (SWIR) within 2 μm to 2.5 μm. It is part of the LEO-LEO microwave and infrared-laser occultation (LMIO) method that enables to retrieve thermodynamic profiles (pressure, temperature, humidity) and altitude levels from microwave signals and profiles of greenhouse gases and further variables such as line-of-sight wind speed from simultaneously measured LIO signals. Due to the novelty of the LMIO method, detailed knowledge of atmospheric influences on LIO signals and of their suitability for accurate trace species retrieval did not yet exist. Here we discuss these influences, assessing effects from refraction, trace species absorption, aerosol extinction and Rayleigh scattering in detail, and addressing clouds, turbulence, wind, scattered solar radiation and terrestrial thermal radiation as well. We show that the influence of refractive defocusing, foreign species absorption, aerosols and turbulence is observable, but can be rendered small to negligible by use of the differential transmission principle with a close frequency spacing of LIO absorption and reference signals within 0.5%. The influences of Rayleigh scattering and terrestrial thermal radiation are found negligible. Cloud-scattered solar radiation can be observable under bright-day conditions, but this influence can be made negligible by a close time spacing (within 5 ms) of interleaved laser-pulse and background signals. Cloud extinction loss generally blocks SWIR signals, except very thin or sub-visible cirrus clouds, which can be addressed by retrieving a cloud layering profile and exploiting it in the trace species retrieval. Wind can have a small influence on the trace species absorption, which can be made negligible by using a simultaneously retrieved or a moderately accurate background wind speed profile. We conclude that

  6. Atmospheric influences on infrared-laser signals used for occultation measurements between Low Earth Orbit satellites

    Directory of Open Access Journals (Sweden)

    S. Schweitzer

    2011-10-01

    Full Text Available LEO-LEO infrared-laser occultation (LIO is a new occultation technique between Low Earth Orbit (LEO satellites, which applies signals in the short wave infrared spectral range (SWIR within 2 μm to 2.5 μm. It is part of the LEO-LEO microwave and infrared-laser occultation (LMIO method that enables to retrieve thermodynamic profiles (pressure, temperature, humidity and altitude levels from microwave signals and profiles of greenhouse gases and further variables such as line-of-sight wind speed from simultaneously measured LIO signals. Due to the novelty of the LMIO method, detailed knowledge of atmospheric influences on LIO signals and of their suitability for accurate trace species retrieval did not yet exist. Here we discuss these influences, assessing effects from refraction, trace species absorption, aerosol extinction and Rayleigh scattering in detail, and addressing clouds, turbulence, wind, scattered solar radiation and terrestrial thermal radiation as well. We show that the influence of refractive defocusing, foreign species absorption, aerosols and turbulence is observable, but can be rendered small to negligible by use of the differential transmission principle with a close frequency spacing of LIO absorption and reference signals within 0.5%. The influences of Rayleigh scattering and terrestrial thermal radiation are found negligible. Cloud-scattered solar radiation can be observable under bright-day conditions, but this influence can be made negligible by a close time spacing (within 5 ms of interleaved laser-pulse and background signals. Cloud extinction loss generally blocks SWIR signals, except very thin or sub-visible cirrus clouds, which can be addressed by retrieving a cloud layering profile and exploiting it in the trace species retrieval. Wind can have a small influence on the trace species absorption, which can be made negligible by using a simultaneously retrieved or a moderately accurate background wind speed profile. We

  7. Dispersive infrared spectroscopy measurements of atmospheric CO₂ using a Fabry-Pérot interferometer sensor.

    Science.gov (United States)

    Chan, K L; Ning, Z; Westerdahl, D; Wong, K C; Sun, Y W; Hartl, A; Wenig, M O

    2014-02-15

    In this paper, we present the first dispersive infrared spectroscopic (DIRS) measurement of atmospheric carbon dioxide (CO2) using a new scanning Fabry-Pérot interferometer (FPI) sensor. The sensor measures the optical spectra in the mid infrared (3,900 nm to 5,220 nm) wavelength range with full width half maximum (FWHM) spectral resolution of 78.8 nm at the CO2 absorption band (~4,280 nm) and sampling resolution of 20 nm. The CO2 concentration is determined from the measured optical absorption spectra by fitting it to the CO2 reference spectrum. Interference from other major absorbers in the same wavelength range, e.g., carbon monoxide (CO) and water vapor (H2O), was taken out by including their reference spectra in the fit as well. The detailed descriptions of the instrumental setup, the retrieval procedure, a modeling study for error analysis as well as laboratory validation using standard gas concentrations are presented. An iterative algorithm to account for the non-linear response of the fit function to the absorption cross sections due to the broad instrument function was developed and tested. A modeling study of the retrieval algorithm showed that errors due to instrument noise can be considerably reduced by using the dispersive spectral information in the retrieval. The mean measurement error of the prototype DIRS CO2 measurement for 1 minute averaged data is about ±2.5 ppmv, and down to ± 0.8ppmv for 10 minute averaged data. A field test of atmospheric CO2 measurements were carried out in an urban site in Hong Kong for a month and compared to a commercial non-dispersive infrared (NDIR) CO2 analyzer. 10 minute averaged data shows good agreement between the DIRS and NDIR measurements with Pearson correlation coefficient (R) of 0.99. This new method offers an alternative approach of atmospheric CO2 measurement featuring high accuracy, correction of non-linear absorption and interference of water vapor. PMID:24291130

  8. Simulation of the infrared signature of transient luminous events in the middle atmosphere for a limb line of sight

    Science.gov (United States)

    Romand, Frédéric; Croizé, Laurence; Payan, Sébastien; Huret, Nathalie

    2016-04-01

    Transient Luminous Events (TLE) are electrical and optical events which occurs above thunderstorms. Visual signatures are reported since the beginning of the 20th century but the first picture is accidentally recorded from a television camera in 1989. Their occurrence is closely linked with the lightning activity below thunderstorms. TLEs are observed from the base of the stratosphere to the thermosphere (15 - 110 km). They are a very brief phenomenon which lasts from 1 to 300 milliseconds. At a worldwide scale, four TLEs occur each minute. The energy deposition, about some tenth of megajoules, is able to ionize, dissociate and excite the molecules of the atmosphere. Atmospheric discharges in the troposphere are important sources of NO and NO2. TLEs might have the same effects at higher altitudes, in the stratosphere. NOx then can affect the concentration of O3 and OH. Consequently, TLEs could be locally important contributors to the chemical budget of the middle atmosphere. The perturbation of the atmospheric chemistry induced by TLEs has the consequence to locally modify the radiations in the infrared during the minutes following the event. The interest of studying the infrared signature of a TLE is twofold. For the atmospheric sciences it allows to link the perturbed composition to the resulting infrared spectrum. Then, some Defense systems like detection and guiding devices are equipped with airborne infrared sensors so that the TLE infrared signature might disturb them. We want to obtain a quantitative and kinetic evaluation of the infrared signature of the atmosphere locally perturbed by a TLE. In order to do so we must model three phenomena. 1) The plasma/chemistry coupling, which describes how the different energetic levels of atmospheric molecules are populated by the energetic deposition of the TLE. This step lasts the time of the lightning itself. 2) The chemical kinetics which describes how these populations will evolve in the following minutes. 3) The

  9. Atmospheric Modelling for the Removal of Telluric Features from Infrared Planetary Spectra

    CERN Document Server

    Cotton, Daniel V; Kedziora-Chudczer, Lucyna

    2013-01-01

    The effects of telluric absorption on infrared spectra present a problem for the observer. Strong molecular absorptions from species whose concentrations vary with time can be particularly challenging to remove precisely. Yet removing these effects is key to accurately determining the composition of many astronomical objects, planetary atmospheres in particular. Here we present a method for removing telluric effects based on a modelling approach. The method relies only on observations usually made by the planetary astronomer, and so is directly comparable with current techniques. We use the modelling approach to process observations made of Jupiter, and Saturnian moon Titan and compare the results with those of the standard telluric division technique, finding the modelling approach to have distinct advantages even in conditions regarded as ideal for telluric division.

  10. [Study on the infrared spectra and raman spectra of steel rusty layer with atmospheric corrosion].

    Science.gov (United States)

    Yang, Xiao-mei

    2006-12-01

    In the present study two methods, infrared and Raman spectral analyses, were used to measure the rusty layer of samples with atmospheric corrosion from Qingdao. The main component rust phase of the rusty layer was observed, showing that the relative content of the rust phase varies with the change in corrosion time. The main component rust phases of the rusty layer were found to be alpha-Fe2O3 , gamma-FeOOH, alpha-FeOOH, delta-FeOOH and Fe3O4, with the relative content of each rust phase of A3 (1) rusty layer sample exhibiting the following relation: gamma-FeOOH> alpha-FeOOH>delta-FeOOH, and the relative contents of other rusty layer samples were found to follow the relation: gamma-FeOOH> delta-FeOOH>alpha-FeOOH. PMID:17361722

  11. Teleradiometer for remote atmospheric sensing in near infrared spectr spectral region

    International Nuclear Information System (INIS)

    A four-channel spaceborne teleradiometer for the measuring of optical characteristics of the atmosphere (noctilucent clouds brightness, etc.) in the near infrared spectral region is described. A rotating optical switch for periodical in-flight sensitivity testing has been installed. The main specifications of the teleradiometer: objective diameter 50 mm, mean wavelengths of spectral zone are changed between 1.2 and 2.7 μm, band half width is 0.05-0.3 μm, field of view 15 min. of arc, dynamic range 80 dB (covered with 4 amplifier outputs), measuring range of spectral densities of is equal 1f radiances-10-2 W.cm-2. ster-1 μm-1, instrument weight 19 kg. Described teleradiometers were installed on board the orbiting space stations ''Salyut 4'' and ''Salyut 6''

  12. The non-uniform, dynamic atmosphere of Betelgeuse observed at mid-infrared wavelengths

    CERN Document Server

    Ravi, V; Townes, C H; Lockwood, S; Mistry, H; Tatebe, K

    2011-01-01

    We present an interferometric study of the continuum surface of the red supergiant star Betelgeuse at 11.15 microns wavelength, using data obtained with the Berkeley Infrared Spatial Interferometer each year between 2006 and 2010. These data allow an investigation of an optically thick layer within 1.4 stellar radii of the photosphere. The layer has an optical depth of ~1 at 11.15 microns, and varies in temperature between 1900 K and 2800 K and in outer radius between 1.16 and 1.36 stellar radii. Electron-hydrogen atom collisions contribute significantly to the opacity of the layer. The layer has a non-uniform intensity distribution that changes between observing epochs. These results indicate that large-scale surface convective activity strongly influences the dynamics of the inner atmosphere of Betelgeuse, and mass-loss processes.

  13. Spectral properties of hydrogen, helium, methane, and ammonia at thermal infrared wavelengths. [for Jupiter atmosphere

    Science.gov (United States)

    Taylor, F. W.; Jones, A. D., III

    1976-01-01

    The paper presents some results of a theoretical and laboratory program to determine the thermal infrared spectral properties of the principal gaseous constituents of the atmosphere of Jupiter. Birnbaum (1975) has measured laboratory spectra in the 16- to 1000-micron wavelength range for hydrogen and hydrogen-helium mixtures at Jovian temperatures. These are compared with theoretically computed spectra in order to determine the temperature dependence of the line strengths in the pressure-induced rotational band and the overlap parameters from the translational band. Existing spectral data for methane do not agree well with measurements of the nu 4 band at room temperature. A revised allocation of line intensities is proposed. Existing data for the nu 2 (10-micron) band of ammonia agree reasonably well with measurements at room temperature and at -77 C, but there are some important discrepancies which remain to be explained.

  14. Estimating the Retrievability of Temperature Profiles from Satellite Infrared Measurements

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A method is developed to assess retrievability, namely the retrieval potential for atmospheric temperature profiles, from satellite infrared measurements in clear-sky conditions. This technique is based upon generalized linear inverse theory and empirical orthogonal function analysis. Utilizing the NCEP global temperature reanalysis data in January and July from 1999 to 2003, the retrievabilities obtained with the Atmospheric Infrared Sounder (AIRS) and the High Resolution Infrared Radiation Sounder/3 (HIRS/3)sounding channel data are derived respectively for each standard pressure level on a global scale. As an incidental result of this study, the optimum truncation number in the method of generalized linear inverse is deduced too. The results show that the retrievabilities of temperature obtained with the two datasets are similar in spatial distribution and seasonal change characteristics. As for the vertical distribution, the retrievabilities are low in the upper and lower atmosphere, and high between 400 hPa and 850 hPa. For the geographical distribution, the retrievabilities are low in the low-latitude oceanic regions and in some regions in Antarctica, and relatively high in mid-high latitudes and continental regions. Compared with the HIRS/3 data, the retrievability obtained with the AIRS data can be improved by an amount between 0.15 and 0.40.

  15. The Influence of Atmospheric Dynamics on the Infrared Spectra and Light Curves of Hot Jupiters

    CERN Document Server

    Fortney, J J; Showman, A P; Marley, M S; Freedman, R S

    2006-01-01

    We explore the infrared spectrum of a three-dimensional dynamical model of planet HD209458b as a function of orbital phase. The dynamical model predicts day-side atmospheric pressure-temperature profiles that are much more isothermal at pressures less than 1 bar than one-dimensional radiative-convective models have found. The resulting day-side thermal spectra are very similar to a blackbody, and only weak water absorption features are seen at short wavelengths. The dayside emission is consequently in significantly better agreement with ground-based and space-based secondary eclipse data than any previous models, which predict strong flux peaks and deep absorption features. At other orbital phases, absorption due to carbon monoxide and methane is also predicted. We compute the spectra under two treatments of atmospheric chemistry: one uses the predictions of equilibrium chemistry, and the other uses non-equilibrium chemistry, which ties the timescales of methane and carbon monoxide chemistry to dynamical time...

  16. Atmospheric influences on infrared-laser signals used for occultation measurements between Low Earth Orbit satellites

    Directory of Open Access Journals (Sweden)

    S. Schweitzer

    2011-05-01

    Full Text Available LEO-LEO infrared-laser occultation (LIO is a new occultation technique between Low Earth Orbit (LEO satellites, which applies signals in the short wave infrared spectral range (SWIR within 2 μm to 2.5 μm. It is part of the LEO-LEO microwave and infrared-laser occultation (LMIO method, recently introduced by Kirchengast and Schweitzer (2011, that enables to retrieve thermodynamic profiles (pressure, temperature, humidity and accurate altitude levels from microwave signals and profiles of greenhouse gases and further variables such as line-of-sight wind speed from simultaneously measured LIO signals. For enabling trace species retrieval based on differential transmission, the LIO signals are spectrally located as pairs, one in the centre of a suitable absorption line of a target species (absorption signal and one close by but outside of any absorption lines (reference signal. Due to the novelty of the LMIO method, detailed knowledge of atmospheric influences on LIO signals and of their suitability for accurate trace species retrieval did not yet exist. Here we discuss the atmospheric influences on the transmission and differential transmission of LIO signals. Refraction effects, trace species absorption (by target species, and cross-sensitivity to foreign species, aerosol extinction and Rayleigh scattering are studied in detail. The influences of clouds, turbulence, wind, scattered solar radiation and terrestrial thermal radiation are discussed as well. We show that the influence of defocusing, foreign species absorption, aerosols and turbulence is observable, but can be rendered small to negligible by use of the differential transmission principle and by a design with close frequency spacing of absorption and reference signals within 0.5 %. The influences of Rayleigh scattering and thermal radiation on the received signal intensities are found negligible. Cloud-scattered solar radiation can be observable under bright-day conditions but this

  17. Comparative Study Among Lease Square Method, Steepest Descent Method, and Conjugate Gradient Method for Atmopsheric Sounder Data Analysis

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2013-09-01

    Full Text Available Comparative study among Least Square Method: LSM, Steepest Descent Method: SDM, and Conjugate Gradient Method: CGM for atmospheric sounder data analysis (estimation of vertical profiles for water vapor is conducted. Through simulation studies, it is found that CGM shows the best estimation accuracy followed by SDM and LSM. Method dependency on atmospheric models is also clarified.

  18. A radiative transfer model to treat infrared molecular excitation in cometary atmospheres

    Science.gov (United States)

    Debout, V.; Bockelée-Morvan, D.; Zakharov, V.

    2016-02-01

    The exospheres of small Solar System bodies are now observed with high spatial resolution from space missions. Interpreting infrared spectra of cometary gases obtained with the VIRTIS experiment onboard the Rosetta cometary mission requires detailed modeling of infrared fluorescence emission in optically thick conditions. Efficient computing methods are required since numerous ro-vibrational lines excited by the Sun need to be considered. We propose a new model working in a 3-D environment to compute numerically the local incoming radiation. It uses a new algorithm using pre-defined directions of ray propagation and ray grids to reduce the CPU cost in time with respect to Monte Carlo methods and to treat correctly the sunlight direction. The model is applied to the ν3 bands of CO2 and H2O at 4.3 μ m and 2.7 μ m respectively, and to the CO ∨ (1 → 0) band at 4.7 μ m. The results are compared to the ones obtained by a 1-D algorithm which uses the Escape Probability (EP) method, and by a 3-D "Coupled Escape Probability" (CEP) model, for different levels of optical thickness. Our results suggest that the total band flux may vary strongly with azimuth for optically thick cases whereas the azimuth average total band flux computed is close to the one obtained with EP. Our model globally predicts less intensity reduction from opacity than the CEP model of Gersch and A'Hearn (Gersch, A.M., A'Hearn, M.F. [2014]. Astrophys. J. 787, 36-56). An application of the model to the observation of CO2, CO and H2O bands in 67/P atmosphere with VIRTIS is presented to predict the evolution of band optical thickness along the mission.

  19. An automated baseline correction protocol for infrared spectra of atmospheric aerosols collected on polytetrafluoroethylene (Teflon) filters

    Science.gov (United States)

    Kuzmiakova, Adele; Dillner, Ann M.; Takahama, Satoshi

    2016-06-01

    A growing body of research on statistical applications for characterization of atmospheric aerosol Fourier transform infrared (FT-IR) samples collected on polytetrafluoroethylene (PTFE) filters (e.g., Russell et al., 2011; Ruthenburg et al., 2014) and a rising interest in analyzing FT-IR samples collected by air quality monitoring networks call for an automated PTFE baseline correction solution. The existing polynomial technique (Takahama et al., 2013) is not scalable to a project with a large number of aerosol samples because it contains many parameters and requires expert intervention. Therefore, the question of how to develop an automated method for baseline correcting hundreds to thousands of ambient aerosol spectra given the variability in both environmental mixture composition and PTFE baselines remains. This study approaches the question by detailing the statistical protocol, which allows for the precise definition of analyte and background subregions, applies nonparametric smoothing splines to reproduce sample-specific PTFE variations, and integrates performance metrics from atmospheric aerosol and blank samples alike in the smoothing parameter selection. Referencing 794 atmospheric aerosol samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011, we start by identifying key FT-IR signal characteristics, such as non-negative absorbance or analyte segment transformation, to capture sample-specific transitions between background and analyte. While referring to qualitative properties of PTFE background, the goal of smoothing splines interpolation is to learn the baseline structure in the background region to predict the baseline structure in the analyte region. We then validate the model by comparing smoothing splines baseline-corrected spectra with uncorrected and polynomial baseline (PB)-corrected equivalents via three statistical applications: (1) clustering analysis, (2) functional group quantification

  20. A balloon-borne microwave limb sounder for stratospheric measurements

    International Nuclear Information System (INIS)

    The balloon-borne microwave limb sounder (BMLS) measures atmospheric thermal emission from millimeter wavelength spectral lines to determine vertical profiles of stratospheric species. The instrument flown to date operates at 205 GHz to measure C10, O3, and H2O2. A 63 GHz radiometer will be added to test the technique for determining tangent point pressure from the MLS experiment on the upper atmosphere research satellite (UARS). Many additional species could also be measured by the BMLS. A radiometer at 270 GHz would provide measurements of HO2, NO2, HNO3, N2O, 16O18O16O, and HCN. With this addition, the BMLS can test the current theory of O3 photochemical balance in the upper stratosphere

  1. A Fourier transform infrared trace gas and isotope analyser for atmospheric applications

    Directory of Open Access Journals (Sweden)

    D. W. T. Griffith

    2012-10-01

    Full Text Available Concern in recent decades about human impacts on Earth's climate has led to the need for improved and expanded measurement capabilities of greenhouse gases in the atmosphere. In this paper we describe in detail an in situ trace gas analyser based on Fourier Transform Infrared (FTIR spectroscopy that is capable of simultaneous and continuous measurements of carbon dioxide (CO2, methane (CH4, carbon monoxide (CO, nitrous oxide (N2O and 13C in CO2 in air with high precision. High accuracy is established by reference to measurements of standard reference gases. Stable water isotopes can also be measured in undried airstreams. The analyser is automated and allows unattended operation with minimal operator intervention. Precision and accuracy meet and exceed the compatibility targets set by the World Meteorological Organisation – Global Atmosphere Watch for baseline measurements in the unpolluted troposphere for all species except 13C in CO2.

    The analyser is mobile and well suited to fixed sites, tower measurements, mobile platforms and campaign-based measurements. The isotopic specificity of the optically-based technique and analysis allows its application in isotopic tracer experiments, for example in tracing variations of 13C in CO2 and 15N in N2O. We review a number of applications illustrating use of the analyser in clean air monitoring, micrometeorological flux and tower measurements, mobile measurements on a train, and soil flux chamber measurements.

  2. Fourier Transform Infrared (FT-IR) Spectroscopy of Atmospheric Trace Gases HCl, NO and SO2

    Science.gov (United States)

    Haridass, C.; Aw-Musse, A.; Dowdye, E.; Bandyopadhyay, C.; Misra, P.; Okabe, H.

    1998-01-01

    Fourier Transform Infrared (FT-IR) spectral data have been recorded in the spectral region 400-4000/cm of hydrogen chloride and sulfur dioxide with I/cm resolution and of nitric oxide with 0.25 cm-i resolution, under quasi-static conditions, when the sample gas was passed through tubings of aluminum, copper, stainless steel and teflon. The absorbance was measured for the rotational lines of the fundamental bands of (1)H(35)Cl and (1)H(37)Cl for pressures in the range 100-1000 Torr and for the (14)N(16)O molecule in the range 100-300 Torr. The absorbance was also measured for individual rotational lines corresponding to the three modes of vibrations (upsilon(sub 1) - symmetric stretch, upsilon(sub 2) - symmetric bend, upsilon(sub 3) - anti-symmetric stretch) of the SO2 molecule in the pressure range 25-150 Torr. A graph of absorbance versus pressure was plotted for the observed rotational transitions of the three atmospherically significant molecules, and it was found that the absorbance was linearly proportional to the pressure range chosen, thereby validating Beer's law. The absorption cross-sections were determined from the graphical slopes for each rotational transition recorded for the HCl, NO and SO2 species. Qualitative and quantitative spectral changes in the FT-IR data will be discussed to identify and characterize various tubing materials with respect to their absorption features.

  3. Near infrared cavity enhanced absorption spectra of atmospherically relevant ether-1, 4-Dioxane

    Science.gov (United States)

    Chandran, Satheesh; Varma, Ravi

    2016-01-01

    1, 4-Dioxane (DX) is a commonly found ether in industrially polluted atmosphere. The near infrared absorption spectra of this compound has been recorded in the region 5900-8230 cm- 1 with a resolution of 0.08 cm- 1 using a novel Fourier transform incoherent broadband cavity-enhanced absorption spectrometer (FT-IBBCEAS). All recorded spectra were found to contain regions that are only weakly perturbed. The possible combinations of fundamental modes and their overtone bands corresponding to selected regions in the measured spectra are tabulated. Two interesting spectral regions were identified as 5900-6400 cm- 1 and 8100-8230 cm- 1. No significant spectral interference due to presence of water vapor was observed suggesting the suitability of these spectral signatures for spectroscopic in situ detection of DX. The technique employed here is much more sensitive than standard Fourier transform spectrometer measurements on account of long effective path length achieved. Hence significant enhancement of weaker absorption lines above the noise level was observed as demonstrated by comparison with an available measurement from database.

  4. Stable isotopic analysis of atmospheric methane by infrared spectroscopy by use of diode laser difference-frequency generation

    OpenAIRE

    Trudeau, Michael E.; Chen, Pin; Garcia, Guilherme de Andrade; Hollberg, Leo W.; Tans, Pieter P.

    2006-01-01

    An infrared absorption spectrometer has been constructed to measure the stable isotopic composition of atmospheric methane samples. The spectrometer employs periodically poled lithium niobate to generate 15 μW of tunable difference-frequency radiation from two near-infrared diode lasers that probe the ν3 rotational-vibrational band of methane at 3.4 μm. To enhance the signal, methane is extracted from 25 l of air by use of a cryogenic chromatographic column and is expanded into the multipass ...

  5. Parametrization of the effect of surface reflection on spectral infrared radiance measurements. Application to IASI

    International Nuclear Information System (INIS)

    The recent launch of the Advanced Infrared Sounder (AIRS) on board EOS-Aqua and the scheduled launch of the Infrared Atmospheric Sounder Interferometer (IASI) on board the Meteorological Operational Satellite (METOP) in 2005 open interesting perspectives for remote sensing applications. Owing to their enhanced spectral resolution and sensitivity, this new generation of high-resolution infrared vertical sounders is first aimed at improving the vertical resolution of temperature and water vapor profile retrievals needed by the weather forecasting community. Another important possible use of these instruments, in the context of the study of global warming, is to permit the retrieval of the concentrations of greenhouse gases like CO2, N2O, CH4, etc. In order to reach these two main objectives, improvement in the modeling of the radiative transfer is therefore necessary. One of the points which still needs some improvements is the contribution of the downward radiation reflected by the surface back to the satellite which is often improperly accounted for in radiative transfer calculation to save computer time. In this article, we show how it is possible to simplify the problem through the computation of a spectrally dependent 'effective' emissivity for which a simple parametrization is proposed, while preserving the accuracy of the results

  6. Measurement of Ecosystem-Atmosphere Exchange of Isotopic CO2 Using Fourier Transform Infrared (FTIR) Spectroscopy

    Science.gov (United States)

    Cambaliza, M. O.; Mount, G.; Lamb, B.; Westberg, H.; Gibson, R.

    2005-12-01

    Analysis of the isotopic content of atmospheric carbon dioxide provides a wealth of information about the complex interaction between the biosphere and the atmosphere. Traditionally, the isotopic content of atmospheric CO2 has been determined by taking grab samples from field sites followed by laboratory mass spectrometry analysis. This procedure severely limits the duration and frequency of measurements. In this work, we investigate the performance of a measurement method that is based on Fourier Transform Infrared (FTIR) spectroscopy. The FTIR separately measures the concentrations of the 12CO2 and 13CO2 isotopomers of carbon dioxide at approximately one minute intervals with very high signal-to-noise ratio using molecular absorption in a 1-meter cell in the 2100 to 2600 cm-1 region of the isotopic vibration-rotation bands. δ13C values are determined with a precision of approximately 0.7‰ every minute, with higher precision obtained by averaging the short integrations. The FTIR system also measures CO2 flux using the disjunct eddy covariance technique, so the net ecosystem exchange (NEE) and isoflux can also be measured, potentially allowing for the partitioning of the NEE into its photosynthetic and respiratory components. First scientific results from this new instrument are presented from two field campaigns conducted in summer 2005 in a poplar forest near Boardman, Oregon. A 25-m tower was used with air inlets at 0.3, 4.1, 7.5, 10.8, 14.0, and 20.6 meters above the ground. These were switched sequentially into the instrument to achieve height resolution in the canopy, or were kept at constant height. Canopy height was 13 meters. Carbon dioxide concentrations are measured to a precision of about 0.7 ppmv from a one-minute integration with higher precisions obtained from time averaging. CO2 isotopic concentrations were measured with a precision of about 2 ppmv/minute. In this work, we present results of temporal and vertical variations of CO2 concentrations

  7. Mesoscale Phenomenon Revealed by an Acoustic Sounder

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Jensen, Niels Otto

    1976-01-01

    A particular phenomenon observed on an acoustic sounder record is analyzed, and is interpreted as being associated with the passing of a land breeze front. A simple physical explanation of the frontal movements is suggested. The actual existence of the land breeze is demonstrated by examination of...

  8. Atmospheric correction of thermal-infrared imagery of the 3-D urban environment acquired in oblique viewing geometry

    OpenAIRE

    F. Meier; D. Scherer; Richters, J.; A. Christen

    2011-01-01

    This research quantifies and discusses atmospheric effects, which alter the radiance observed by a ground-based thermal-infrared (TIR) camera. The TIR camera is mounted on a boom at a height of 125 m above ground on top of a high-rise building in the city of Berlin, Germany (52.4556° N, 13.3200° E) and observes the Earth's surface. The study shows that atmospheric correction of TIR imagery of the three-dimensional (3-D) urban environment acquired in oblique viewing geometry has to account for...

  9. DISTRIBUTION OF CO{sub 2} IN SATURN'S ATMOSPHERE FROM CASSINI/CIRS INFRARED OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, M. M.; LeClair, A. [NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States); Woodard, E.; Young, M.; Stanbro, M. [University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Flasar, F. M.; Achterberg, R. K.; Bjoraker, G.; Brasunas, J.; Jennings, D. E. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kunde, V. G., E-mail: Mian.M.Abbas@nasa.gov, E-mail: Andre.C.LeClair@nasa.gov, E-mail: eaw0009@uah.edu, E-mail: mcs0001@uah.edu, E-mail: youngmm@uah.edu, E-mail: f.m.flasar@nasa.gov, E-mail: virgil.g.kunde@gsfc.nasa.gov [University of Maryland, College Park, MD 20742 (United States); Collaboration: and the Cassini/CIRS team

    2013-10-20

    This paper focuses on the CO{sub 2} distribution in Saturn's atmosphere based on analysis of infrared spectral observations of Saturn made by the Composite Infrared Spectrometer aboard the Cassini spacecraft. The Cassini spacecraft was launched in 1997 October, inserted in Saturn's orbit in 2004 July, and has been successfully making infrared observations of Saturn, its rings, Titan, and other icy satellites during well-planned orbital tours. The infrared observations, made with a dual Fourier transform spectrometer in both nadir- and limb-viewing modes, cover spectral regions of 10-1400 cm{sup –1}, with the option of variable apodized spectral resolutions from 0.53 to 15 cm{sup –1}. An analysis of the observed spectra with well-developed radiative transfer models and spectral inversion techniques has the potential to provide knowledge of Saturn's thermal structure and composition with global distributions of a series of gases. In this paper, we present an analysis of a large observational data set for retrieval of Saturn's CO{sub 2} distribution utilizing spectral features of CO{sub 2} in the Q-branch of the ν{sub 2} band, and discuss its possible relationship to the influx of interstellar dust grains. With limited spectral regions available for analysis, due to low densities of CO{sub 2} and interference from other gases, the retrieved CO{sub 2} profile is obtained as a function of a model photochemical profile, with the retrieved values at atmospheric pressures in the region of ∼1-10 mbar levels. The retrieved CO{sub 2} profile is found to be in good agreement with the model profile based on Infrared Space Observatory measurements with mixing ratios of ∼4.9 × 10{sup –10} at atmospheric pressures of ∼1 mbar.

  10. CORSAIR-Calibrated Observations of Radiance Spectra from the Atmosphere in the Far- Infrared

    Science.gov (United States)

    Mlynczak, M. G.; Johnson, D.; Abedin, N.; Liu, X.; Kratz, D.; Jordan, D.; Wang, J.; Bingham, G.; Latvakoski, H.; Bowman, K.; Kaplan, S.

    2008-12-01

    The CORSAIR project is a new NASA Instrument Incubator Project (IIP) whose primary goal is to develop and demonstrate the necessary technologies to achieve SI-traceable, on-orbit measurements of Earth's spectral radiance in the far-infrared (far-IR). The far-IR plays a vital role in the energy balance of the Earth yet its spectrum has not been comprehensively observed from space for the purposes of climate sensing. The specific technologies being developed under CORSAIR include: passively cooled, antenna-coupled terahertz detectors for the far-IR (by Raytheon Vision Systems); accurately calibrated, SI-traceable blackbody sources for the far-IR (by Space Dynamics Laboratory); and high-performance broad bandpass beamsplitters (by ITT). These technologies complement those already developed under past Langley IIP projects (FIRST; INFLAME) in the areas of Fourier Transform Spectrometers and dedicated far-IR beamsplitters. The antenna-coupled far-IR detectors will be validated in the FIRST instrument at Langley. The SI-traceable far-IR blackbodies will be developed in conjunction with the National Institute of Standards and Technology (NIST). An overview of the CORSAIR technologies will be presented as well as their larger role in the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. Upon successful completion of CORSAIR these IIP efforts will provide the necessary technologies to achieve the first comprehensive, accurate, high-resolution measurements from a satellite of the far-IR spectrum of the Earth and its atmosphere, enabling major advances in our understanding of Earth's climate.

  11. The Zugspitze radiative closure experiment: quantification of the near-infrared water vapor continuum from atmospheric measurements

    Science.gov (United States)

    Reichert, Andreas; Sussmann, Ralf; Rettinger, Markus

    2016-04-01

    Inaccuracies in the description of atmospheric radiative processes are among the major shortcomings of current climate models. Especially the contribution by water vapor, the primary greenhouse gas in the Earth's atmosphere, currently still lacks sufficiently accurate quantification. The main focus of our study is on the so-called water vapor continuum absorption in the near-infrared spectral range, which is of crucial importance for atmospheric radiative processes. To date, the quantification of this contribution originates exclusively from laboratory experiments which show contradictory results and whose findings are not unambiguously transferable to atmospheric conditions. The aim of the Zugspitze radiative closure study is therefore to obtain, to our knowledge for the first time, an exact characterization of the near-infrared water vapor continuum absorption using atmospheric measurements. This enables validation and, if necessary, improvements of the radiative transfer codes used in current climate models. The closure experiment comprises near-infrared spectral radiance measurements using a solar absorption FTIR spectrometer. These measurements are then compared to synthetic radiance spectra computed by means of a high-resolution radiative transfer model. The spectral residuals, i.e. the difference between measured and calculated spectral radiances can then be used to quantify errors in the description of water vapor absorption. Due to the extensive permanent instrumentation available at the Zugspitze observatory, the atmospheric state used as an input to the model calculations can be constrained with high accuracy. Additionally, we employ a novel radiometric calibration strategy for the solar FTIR spectral radiance measurements based on a combination of the Langley method and measurements of a medium-temperature blackbody source. These prerequisites enable accurate quantification of the water vapor continuum in the near-infrared spectral region, where

  12. Geo-STAR: A Geostationary Microwave Sounder for the Future

    Science.gov (United States)

    Lambrigtsen, Bjorn H.; Brown, S. T.; Dinardo, S. J.; Gaier, T. C.; Kangaslahti, P. P.; Tanner, A. B.

    2007-01-01

    The Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) is a new Earth remote sensing instrument concept that has been under development at the Jet Propulsion Laboratory. First conceived in 1998 as a NASA New Millennium Program mission and subsequently developed in 2003-2006 as a proof-of-concept prototype under the NASA Instrument Incubator Program, it is intended to fill a serious gap in our Earth remote sensing capabilities - namely the lack of a microwave atmospheric sounder in geostationary orbit. The importance of such observations have been recognized by the National Academy of Sciences National Research Council, which recently released its report on a 'Decadal Survey' of NASA Earth Science activities1. One of the recommended missions for the next decade is a geostationary microwave sounder. GeoSTAR is well positioned to meet the requirements of such a mission, and because of the substantial investment NASA has already made in GeoSTAR technology development, this concept is fast approaching the necessary maturity for implementation in the next decade. NOAA is also keenly interested in GeoSTAR as a potential payload on its next series of geostationary weather satellites, the GOES-R series. GeoSTAR, with its ability to map out the three-dimensional structure of temperature, water vapor, clouds, precipitation and convective parameters on a continual basis, will significantly enhance our ability to observe hurricanes and other severe storms. In addition, with performance matching that of current and next generation of low-earth-orbiting microwave sounders, GeoSTAR will also provide observations important to the study of the hydrologic cycle, atmospheric processes and climate variability and trends. In particular, with GeoSTAR it will be possible to fully resolve the diurnal cycle. We discuss the GeoSTAR concept and basic design, the performance of the prototype, and a number of science applications that will be possible with GeoSTAR. The work reported

  13. GeoSTAR: a geostationary microwave sounder for the future

    Science.gov (United States)

    Lambrigtsen, B. H.; Brown, S. T.; Dinardo, S. J.; Gaier, T. C.; Kangaslahti, P. P.; Tanner, A. B.

    2007-09-01

    The Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) is a new Earth remote sensing instrument concept that has been under development at the Jet Propulsion Laboratory. First conceived in 1998 as a NASA New Millennium Program mission and subsequently developed in 2003-2006 as a proof-of-concept prototype under the NASA Instrument Incubator Program, it is intended to fill a serious gap in our Earth remote sensing capabilities - namely the lack of a microwave atmospheric sounder in geostationary orbit. The importance of such observations have been recognized by the National Academy of Sciences National Research Council, which recently released its report on a "Decadal Survey" of NASA Earth Science activities. One of the recommended missions for the next decade is a geostationary microwave sounder. GeoSTAR is well positioned to meet the requirements of such a mission, and because of the substantial investment NASA has already made in GeoSTAR technology development, this concept is fast approaching the necessary maturity for implementation in the next decade. NOAA is also keenly interested in GeoSTAR as a potential payload on its next series of geostationary weather satellites, the GOES-R series. GeoSTAR, with its ability to map out the three-dimensional structure of temperature, water vapor, clouds, precipitation and convective parameters on a continual basis, will significantly enhance our ability to observe hurricanes and other severe storms. In addition, with performance matching that of current and next generation of low-earth-orbiting microwave sounders, GeoSTAR will also provide observations important to the study of the hydrologic cycle, atmospheric processes and climate variability and trends. In particular, with GeoSTAR it will be possible to fully resolve the diurnal cycle. We discuss the GeoSTAR concept and basic design, the performance of the prototype, and a number of science applications that will be possible with GeoSTAR. The work reported

  14. Atmospheric density remote sensing of mesosphere and thermosphere to be used for spacecraft design by adopting VHF radar and HF Doppler sounder at low latitude west Pacific site during winter time

    Science.gov (United States)

    Hung, R. J.; Tsao, Y. D.; Johnson, D. L.; Chen, A. J.; Lee, C. C.

    1989-01-01

    Simultaneous observations of VHF radar and HF Doppler array systems located at Chung Li (Taiwan) are used to observe three-dimensional wind speeds and gravity waves. The density perturbations are determined at different altitudes of the mesosphere and thermosphere during weak convective motions of the cold front in the winter. The present observations are believed to be valuable for space projects dealing with the low-latitude atmosphere.

  15. Assignment of the Fundamental Modes of Hydroxyacetone Using Gas-Phase Infrared, Far-Infrared, Raman and ab Initio Methods: Band Strengths for Atmospheric Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lindenmaier, Rodica; Tipton, Nicole M.; Sams, Robert L.; Brauer, Carolyn S.; Blake, Thomas A.; Williams, Stephen D.; Johnson, Timothy J.

    2016-08-04

    Hydroxyacetone (acetol) is a simple organic molecule of interest in both the astrophysical and atmospheric communities, having recently been observed in biomass burning events, as well as a known degradation product of isoprene oxidation. However, its vibrational assignment has never been fully completed, and few quantitative data are available for its detection via infrared spectroscopy. Our recent acquisition of both the pressure-broadened gas-phase data and the far-IR spectra now allow for unambiguous assignment of several (new) bands. In particular, the observed C-type bands of several fundamentals (particularly in the far-infrared) and a few combination bands demonstrate that the monomer is in a planar (Cs) conformation, at least a majority of the time. As suggested by other researchers, the monomer is a cis-cis conformer stabilized by an intramolecular O—H···O=C hydrogen bond forming a five-membered planar ring structure. Band assignments in the Cs point group are justified (at least for a good fraction of the molecules in the ensemble) by the presence of the C-type bands. The results and band assignments are well confirmed by both ab initio MP2-ccpvtz calculations as well as GAMESS (B3LYP) theoretical calculations. In addition, using vetted methods for quantitative measurements, we report the first IR absorption band strengths of acetol (also in electronic format) that can be used for atmospheric monitoring and other applications.

  16. GARLIC - A general purpose atmospheric radiative transfer line-by-line infrared-microwave code: Implementation and evaluation

    Science.gov (United States)

    Schreier, Franz; Gimeno García, Sebastián; Hedelt, Pascal; Hess, Michael; Mendrok, Jana; Vasquez, Mayte; Xu, Jian

    2014-04-01

    A suite of programs for high resolution infrared-microwave atmospheric radiative transfer modeling has been developed with emphasis on efficient and reliable numerical algorithms and a modular approach appropriate for simulation and/or retrieval in a variety of applications. The Generic Atmospheric Radiation Line-by-line Infrared Code - GARLIC - is suitable for arbitrary observation geometry, instrumental field-of-view, and line shape. The core of GARLIC's subroutines constitutes the basis of forward models used to implement inversion codes to retrieve atmospheric state parameters from limb and nadir sounding instruments. This paper briefly introduces the physical and mathematical basics of GARLIC and its descendants and continues with an in-depth presentation of various implementation aspects: An optimized Voigt function algorithm combined with a two-grid approach is used to accelerate the line-by-line modeling of molecular cross sections; various quadrature methods are implemented to evaluate the Schwarzschild and Beer integrals; and Jacobians, i.e. derivatives with respect to the unknowns of the atmospheric inverse problem, are implemented by means of automatic differentiation. For an assessment of GARLIC's performance, a comparison of the quadrature methods for solution of the path integral is provided. Verification and validation are demonstrated using intercomparisons with other line-by-line codes and comparisons of synthetic spectra with spectra observed on Earth and from Venus.

  17. Microwave Limb Sounder/El Nino Watch - December, 1997

    Science.gov (United States)

    1998-01-01

    This image shows differences in atmospheric water vapor relative to a normal (average) year in the Earth's upper troposphere about 10 kilometers (6 miles) above the surface. The measurements were taken by the Microwave Limb Sounder (MLS) instrument aboard NASA's Upper Atmosphere Research Satellite (UARS). These data, collected in late December 1997, show higher than normal levels of water vapor (red) over the central and eastern Pacific which indicates the presence of an El Nino condition. At the same time, the western Pacific (blue) is much drier than normal. The unusually moist air above the central and eastern Pacific is a consequence of the much warmer-than-normal ocean waters which occur during El Nino. Warmer water evaporates at a higher rate and the resulting warm moist air rises and forms tall cloud towers. In the tropics, the warm water and the resulting tall cloud towers typically produce large amounts of rain. These data show significant increases in the amount of atmospheric moisture off the coast of Peru and Ecuador since measurements were made in November 1997. The maximum water temperature in the eastern tropical Pacific, as measured by the National Oceanic and Atmospheric Administration (NOAA), is still higher than normal and these high ocean temperatures are likely responsible for an increase in evaporation and the subsequent rise in humidity.

  18. Analysis and demonstration of atmospheric methane monitoring by mid-infrared open-path chirped laser dispersion spectroscopy.

    Science.gov (United States)

    Daghestani, Nart S; Brownsword, Richard; Weidmann, Damien

    2014-12-15

    Atmospheric methane concentration levels were detected using a custom built laser dispersion spectrometer in a long open-path beam configuration. The instrument is driven by a chirped distributed feedback mid-infrared quantum cascade laser centered at ~1283.46 cm-1 and covers intense rotational-vibrational transitions from the fundamental ν4 band of methane. A full forward model simulating molecular absorption and dispersion profiles, as well as instrumental noise, is demonstrated. The instrument's analytical model is validated and used for quantitative instrumental optimization. The temporal evolution of atmospheric methane mixing ratios is retrieved using a fitting algorithm based on the model. Full error propagation analysis on precision gives a normalized sensitivity of ~3 ppm.m.Hz-0.5 for atmospheric methane. PMID:25607487

  19. Atmospheric correction of thermal-infrared imagery of the 3-D urban environment acquired in oblique viewing geometry

    Directory of Open Access Journals (Sweden)

    F. Meier

    2010-12-01

    Full Text Available This research quantifies and discusses atmospheric effects that alter the radiance observed by a ground-based thermal-infrared (TIR camera mounted on top of a high-rise building in the city of Berlin, Germany. The study shows that atmospheric correction of ground-based TIR imagery of the three-dimensional (3-D urban environment acquired in oblique viewing geometry has to account for spatial variability of line-of-sight (LOS geometry. We present an atmospheric correction procedure that uses these spatially distributed LOS geometry parameters, the radiative transfer model MODTRAN 5.2 and atmospheric profile data derived from meteorological measurements in the field of view (FOV of the TIR camera. The magnitude of atmospheric effects varies during the analysed 24-hourly period (8 August 2009 and is particularly notable for surfaces showing a strong surface-to-air temperature difference. The differences between uncorrected and corrected TIR imagery reach up to 7.7 K at 12:00. Atmospheric effects are biased up to 4.3 K at 12:00 and up to 0.6 K at 24:00, if non-spatially distributed LOS parameters are used.

  20. GARLIC — A general purpose atmospheric radiative transfer line-by-line infrared-microwave code: Implementation and evaluation

    International Nuclear Information System (INIS)

    A suite of programs for high resolution infrared-microwave atmospheric radiative transfer modeling has been developed with emphasis on efficient and reliable numerical algorithms and a modular approach appropriate for simulation and/or retrieval in a variety of applications. The Generic Atmospheric Radiation Line-by-line Infrared Code — GARLIC — is suitable for arbitrary observation geometry, instrumental field-of-view, and line shape. The core of GARLIC's subroutines constitutes the basis of forward models used to implement inversion codes to retrieve atmospheric state parameters from limb and nadir sounding instruments. This paper briefly introduces the physical and mathematical basics of GARLIC and its descendants and continues with an in-depth presentation of various implementation aspects: An optimized Voigt function algorithm combined with a two-grid approach is used to accelerate the line-by-line modeling of molecular cross sections; various quadrature methods are implemented to evaluate the Schwarzschild and Beer integrals; and Jacobians, i.e. derivatives with respect to the unknowns of the atmospheric inverse problem, are implemented by means of automatic differentiation. For an assessment of GARLIC's performance, a comparison of the quadrature methods for solution of the path integral is provided. Verification and validation are demonstrated using intercomparisons with other line-by-line codes and comparisons of synthetic spectra with spectra observed on Earth and from Venus. - Highlights: • High resolution infrared-microwave radiative transfer model. • Discussion of algorithmic and computational aspects. • Jacobians by automatic/algorithmic differentiation. • Performance evaluation by intercomparisons, verification, validation

  1. Dispersive infrared spectroscopy measurements of atmospheric CO{sub 2} using a Fabry–Pérot interferometer sensor

    Energy Technology Data Exchange (ETDEWEB)

    Chan, K.L. [School of Energy and Environment, City University of Hong Kong (Hong Kong); Ning, Z., E-mail: zhining@cityu.edu.hk [School of Energy and Environment, City University of Hong Kong (Hong Kong); Guy Carpenter Climate Change Centre, City University of Hong Kong (Hong Kong); Westerdahl, D. [Ability R and D Energy Research Centre, City University of Hong Kong (Hong Kong); Wong, K.C. [School of Energy and Environment, City University of Hong Kong (Hong Kong); Sun, Y.W. [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei (China); Hartl, A. [School of Energy and Environment, City University of Hong Kong (Hong Kong); Wenig, M.O. [Meteorological Institute, Ludwig-Maximilians-Universität Munich (Germany)

    2014-02-01

    In this paper, we present the first dispersive infrared spectroscopic (DIRS) measurement of atmospheric carbon dioxide (CO{sub 2}) using a new scanning Fabry–Pérot interferometer (FPI) sensor. The sensor measures the optical spectra in the mid infrared (3900 nm to 5220 nm) wavelength range with full width half maximum (FWHM) spectral resolution of 78.8 nm at the CO{sub 2} absorption band (∼ 4280 nm) and sampling resolution of 20 nm. The CO{sub 2} concentration is determined from the measured optical absorption spectra by fitting it to the CO{sub 2} reference spectrum. Interference from other major absorbers in the same wavelength range, e.g., carbon monoxide (CO) and water vapor (H{sub 2}O), was taken out by including their reference spectra in the fit as well. The detailed descriptions of the instrumental setup, the retrieval procedure, a modeling study for error analysis as well as laboratory validation using standard gas concentrations are presented. An iterative algorithm to account for the non-linear response of the fit function to the absorption cross sections due to the broad instrument function was developed and tested. A modeling study of the retrieval algorithm showed that errors due to instrument noise can be considerably reduced by using the dispersive spectral information in the retrieval. The mean measurement error of the prototype DIRS CO{sub 2} measurement for 1 minute averaged data is about ± 2.5 ppmv, and down to ± 0.8 ppmv for 10 minute averaged data. A field test of atmospheric CO{sub 2} measurements were carried out in an urban site in Hong Kong for a month and compared to a commercial non-dispersive infrared (NDIR) CO{sub 2} analyzer. 10 minute averaged data shows good agreement between the DIRS and NDIR measurements with Pearson correlation coefficient (R) of 0.99. This new method offers an alternative approach of atmospheric CO{sub 2} measurement featuring high accuracy, correction of non-linear absorption and interference of water

  2. Herbig stars' near-infrared excess: An origin in the protostellar disk's magnetically supported atmosphere

    International Nuclear Information System (INIS)

    Young stars with masses 2-8 times solar, the Herbig Ae and Be stars, often show a near-infrared excess too large to explain with a hydrostatically supported circumstellar disk of gas and dust. At the same time, the accretion flow carrying the circumstellar gas to the star is thought to be driven by magnetorotational turbulence, which, according to numerical MHD modeling, yields an extended low-density atmosphere supported by the magnetic fields. We demonstrate that the base of the atmosphere can be optically thick to the starlight and that the parts lying near 1 AU are tall enough to double the fraction of the stellar luminosity reprocessed into the near-infrared. We generate synthetic spectral energy distributions (SEDs) using Monte Carlo radiative transfer calculations with opacities for submicron silicate and carbonaceous grains. The synthetic SEDs closely follow the median Herbig SED constructed recently by Mulders and Dominik and, in particular, match the large near-infrared flux, provided the grains have a mass fraction close to interstellar near the disk's inner rim.

  3. MID-INFRARED PROPERTIES OF DISK AVERAGED OBSERVATIONS OF EARTH WITH AIRS

    International Nuclear Information System (INIS)

    We have investigated mid-infrared spectra of Earth obtained by the Atmospheric Infrared Sounder (AIRS) instrument on-board the AQUA spacecraft to explore the characteristics that may someday be observed in extrasolar terrestrial planets. We have used the AIRS infrared (R ∼ 1200; 3.75-15.4 μm) spectra to construct directly observed high-resolution spectra of the only known life bearing planet, Earth. The AIRS spectra are the first such spectra that span the seasons. We investigate the rotational and seasonal spectral variations that would arise due to varying cloud amount and viewing geometry and we explore what signatures may be observable in the mid-infrared by the next generation of telescopes capable of observing extrasolar terrestrial planets.

  4. Retrieving Atmospheric Precipitable Water Vapor Using Artificial Neural Network Approach

    Directory of Open Access Journals (Sweden)

    Wang Xin

    2013-07-01

    Full Text Available Discussing of water vapor and its variation is the important issue for synoptic meteorology and meteorology. In physical Atmospheric, the moisture content of the earth atmosphere is one of the most important parameters, it is hard to represent water vapor because of its space-time variation. High-spectral resolution Atmospheric Infrared Sounder (AIRS data can be used to retrieve the small scale vertical structure of air temperature, which provided a more accurate and good initial field for the numerical forecasting and the large-scale weather analysis. This paper proposes an artificial neural network to retrieve the clear sky atmospheric radiation data from AIRS and comparing with the AIRS Level-2 standard product, and gain a good inversion results.

  5. The Atmospheres of Titan and Saturn in the Infrared from Cassini: The Interplay Between Observation and Laboratory Studies

    Science.gov (United States)

    Jennings, D. E.; Nixon, C. A.; Flasar, F. M.; Kunde, V. G.; Coustenis, A.

    2011-01-01

    The Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft has been recording spectra of Saturn and Titan since its arrival in the Saturn system in 2004. CIRS, a Fourier transform spectrometer, observes the thermal infrared spectrum of both atmospheres from 10 to 1500/cm with resolutions up to 0.5/cm (Flasar et al. 2004). From these data CIRS provides global coverage of the molecular composition of the stratosphere and troposphere, as well as maps of temperature and winds. From such studies CIRS helps reveal the chemistry and evolutionary history of Saturn and Titan and their relationships to other Solar System bodies. The Cassini mission is continuing until 2017, permitting CIRS to search for atmospheric changes during more than a Saturnian season. By combining with results from Voyager (1980, 1981) the baseline becomes more than one Saturnian year (Coustenis et al. 2011). CIRS spectroscopy of the atmospheres of Saturn and Titan has raised a variety of questions that require new laboratory studies. A complete understanding of the CIRS high-resolution atmospheric spectra cannot be fully achieved without new or improved line positions and intensities for some trace molecules (e.g., Nixon et al. 2009). Isotopic variants of some of the more abundant species often need improved line parameters in order to derive isotopic ratios (e.g., Coustenis et al. 2008 and Fletcher et a!. 2009). Isotopic ratios contain information about the history of an atmosphere if experimental fractionation rates are available (Jennings et al. 2009). Some aerosol and haze features continue to defy identification and will not be explained without better knowledge of how these materials are formed and until we obtain their laboratory spectra. The interaction between CIRS investigations and laboratory research has been productive and has already led to new discoveries.

  6. Optical parametric oscillators in lidar sounding of trace atmospheric gases in the mid infrared region

    Science.gov (United States)

    Romanovskii, O. A.; Sadovnikov, S. A.; Kharchenko, O. V.; Shumskii, V. K.; Yakovlev, S. V.

    2015-12-01

    Applicability of a KTA crystal-based laser system with optical parametric generation to lidar sounding of the atmosphere in the spectral range 3-4 μm is studied in this work. A technique developed for lidar sounding of trace atmospheric gases is based on differential absorption (DIAL) technique and differential optical absorption spectroscopy (DOAS). The DIAL-DOAS technique is tested to estimate its efficiency for lidar sounding of atmospheric trace gases.

  7. Freshness assessment of thawed and chilled cod fillets packed in modified atmosphere using near-infrared spectroscopy

    DEFF Research Database (Denmark)

    Bøknæs, Niels; Jensen, K.N.; Andersen, Charlotte Møller; Martens, H.

    2002-01-01

    Near-infrared reflectance (NIR) spectra was recorded of 105 samples of cod mince prepared from chill stored thawed cod fillets of varying quality in modified atmosphere packaging (MAP). Traditional chemical, physical, microbiological and sensory quality methods developed for assessing fresh fish...... predicted duration of chill storage period (days at 2 degreesC). The root-mean-square error of cross- validation (RMSECV) was 3.4 d at 2 degreesC. NIR measurements provided promising results for evaluation of freshness for thawed-chilled MAP cod fillets completing the traditionally quality methods. However...

  8. Lessons Learned from Previous Space-Borne Sounders as a Guide to Future Sounder Development

    Science.gov (United States)

    Benson, Robert F.; Deshpande, Manohar D.; Farrell,William M.; Fung, Shing F.; Osherovich, Vladimir A.; Pfaff, Rovert E.; Rowland, Douglas E.; Adrian, Mark L.

    2008-01-01

    Space-borne radio sounding is considered to be the gold standard for electron-density (N(sub e)) measurements compared to other techniques even under low-density conditions, such as N(sub e) future sounder to satisfy specific science requirements with minimal spacecraft resources.

  9. Thermal monitoring of transport infrastructures by infrared thermography coupled with inline local atmospheric conditions survey

    Science.gov (United States)

    Dumoulin, J.

    2013-09-01

    An infrared system architecture (software and hardware) has been studied and developed to allow long term monitoring of transport infrastructures in a standalone configuration. It is based on the implementation of low cost infrared thermal cameras (equipped with uncooled microbolometer focal plane array) available on the market coupled with other measurement systems. All data collected feed simplified radiative models running on GPU available on small PC to produce corrected thermal map of the surveyed structure at selected time step. Furthermore, added Web-enabled capabilities of this new infrared measurement system are also presented and discussed. A prototype of this system was tested and evaluated on real infrastructure opened to traffic. Results obtained by image and signal processing are presented. Finally, conclusions and perspectives for new implementation and new functionalities are presented and discussed.

  10. The Atmospheres of Saturn and Titan in the Near-Infrared: First Results of Cassini/VIMS

    Science.gov (United States)

    Baines, K. H.; Drossart, P.; Momary, T. W.; Formisano, V.; Griffith, C.; Bellucci, G.; Bibring, J. P.; Brown, R. H.; Buratti, B. J.; Capaccioni, F.; Cerroni, P.; Clark, R. N.; Coradini, A.; Combes, M.; Cruikshank, D. P.; Jaumann, R.; Langevin, Y.; Matson, D. L.; McCord, T. B.; Mennella, V.; Nelson, R. M.; Nicholson, P. D.; Sicardy, B.; Sotin, C.

    2005-01-01

    The wide spectral coverage and extensive spatial, temporal, and phase-angle mapping capabilities of the Visual Infrared Mapping Spectrometer (VIMS) onboard the Cassini-Huygens Orbiter are producing fundamental new insights into the nature of the atmospheres of Saturn and Titan. For both bodies, VIMS maps over time and solar phase angles provide information for a multitude of atmospheric constituents and aerosol layers, providing new insights into atmospheric structure and dynamical and chemical processes. For Saturn, salient early results include evidence for phosphine depletion in relatively dark and less cloudy belts at temperate and mid-latitudes compared to the relatively bright and cloudier Equatorial Region, consistent with traditional theories of belts being regions of relative downwelling. Additional Saturn results include (1) the mapping of enhanced trace gas absorptions at the south pole, and (2) the first high phase-angle, high-spatial-resolution imagery of CH4 fluorescence. An additional fundamental new result is the first nighttime near-infrared mapping of Saturn, clearly showing discrete meteorological features relatively deep in the atmosphere beneath the planet's sunlit haze and cloud layers, thus revealing a new dynamical regime at depth where vertical dynamics is relatively more important than zonal dynamics in determining cloud morphology. Zonal wind measurements at deeper levels than previously available are achieved by tracking these features over multiple days, thereby providing measurements of zonal wind shears within Saturn's troposphere when compared to cloudtop movements measured in reflected sunlight. For Titan, initial results include (1) the first detection and mapping of thermal emission spectra of CO, CO2, and CH3D on Titan's nightside limb, (2) the mapping of CH4 fluorescence over the dayside bright limb, extending to approximately 750 km altitude, (3) wind measurements of approximately 0.5 ms(exp -1), favoring prograde, from the

  11. Evaluating calibration strategies for isotope ratio infrared spectroscopy for atmospheric 13CO2 / 12CO2 measurement

    Directory of Open Access Journals (Sweden)

    X.-F. Wen

    2013-06-01

    Full Text Available Isotope ratio infrared spectroscopy (IRIS provides an in situ technique for measuring δ13C in atmospheric CO2. A number of methods have been proposed for calibrating the IRIS measurements, but few studies have systematically evaluated their accuracy for atmospheric applications. In this study, we carried out laboratory and ambient measurements with two commercial IRIS analyzers and compared the accuracy of four calibration strategies. We found that calibration based on the 12C and 13C mixing ratios (Bowling et al., 2003 and on linear interpolation of the measured delta using the mixing ratio of the major isotopologue (Lee et al., 2005 yielded accuracy better than 0.06‰. Over a 7-day atmospheric measurement in Beijing, the two analyzers agreed to within −0.02 ± 0.18‰ after proper calibration. However, even after calibration the difference between the two analyzers showed a slight correlation with concentration, and this concentration dependence propagated through the Keeling analysis, resulting in a much larger difference of 2.44‰ for the Keeling intercept. The high sensitivity of the Keeling analysis to the concentration dependence underscores the challenge of IRIS for atmospheric research.

  12. Evaluating calibration strategies for isotope ratio infrared spectroscopy for atmospheric 13CO2/12CO2 measurement

    Directory of Open Access Journals (Sweden)

    X. Lee

    2013-01-01

    Full Text Available Isotope ratio infrared spectroscopy (IRIS provides an in-situ technique for measuring δ13C in atmospheric CO2. A number of methods have been proposed for calibrating the IRIS measurements, but few studies have systematically evaluated their accuracy for atmospheric applications. In this study, we carried out laboratory and ambient measurements with two commercial IRIS analyzers and compared the accuracy of four calibration strategies. We found that calibration based on the 12C and 13C mixing ratios (Bowling et al., 2003 and that based on linear interpolation of the measured delta using the mixing ratio of the major isotopologue (Lee et al., 2005 yielded accuracy better than 0.06‰. Over a 7-day atmospheric measurement in Beijing, the two analyzers differed by 9.44 ± 1.65‰ (mean ± 1 standard deviation of hourly values before calibration and agreed to within −0.02 ± 0.18‰ after properly calibration. However, even after calibration the difference between the two analyzers showed a slight correlation with concentration, and this concentration dependence propagated through the Keeling analysis resulting in a much larger difference of 2.44‰ for the Keeling intercept. The high sensitivity of the Keeling analysis to the concentration dependence underscores the challenge of IRIS for atmospheric research.

  13. Evaluating calibration strategies for isotope ratio infrared spectroscopy for atmospheric 13CO2 / 12CO2 measurement

    Science.gov (United States)

    Wen, X.-F.; Meng, Y.; Zhang, X.-Y.; Sun, X.-M.; Lee, X.

    2013-06-01

    Isotope ratio infrared spectroscopy (IRIS) provides an in situ technique for measuring δ13C in atmospheric CO2. A number of methods have been proposed for calibrating the IRIS measurements, but few studies have systematically evaluated their accuracy for atmospheric applications. In this study, we carried out laboratory and ambient measurements with two commercial IRIS analyzers and compared the accuracy of four calibration strategies. We found that calibration based on the 12C and 13C mixing ratios (Bowling et al., 2003) and on linear interpolation of the measured delta using the mixing ratio of the major isotopologue (Lee et al., 2005) yielded accuracy better than 0.06‰. Over a 7-day atmospheric measurement in Beijing, the two analyzers agreed to within -0.02 ± 0.18‰ after proper calibration. However, even after calibration the difference between the two analyzers showed a slight correlation with concentration, and this concentration dependence propagated through the Keeling analysis, resulting in a much larger difference of 2.44‰ for the Keeling intercept. The high sensitivity of the Keeling analysis to the concentration dependence underscores the challenge of IRIS for atmospheric research.

  14. Validation of the Aura High Resolution Dynamics Limb Sounder geopotential heights

    Directory of Open Access Journals (Sweden)

    L. L. Smith

    2014-02-01

    Full Text Available Global satellite observations from the EOS Aura spacecraft's High Resolution Dynamics Limb Sounder (HIRDLS of temperature and geopotential height (GPH are discussed. The accuracy, resolution and precision of the HIRDLS version 7 algorithms are assessed and data screening recommendations are made. Comparisons with GPH from observations, reanalyses and models including European Center for Medium-Range Weather Forecasts Interim Reanalysis (ERA-Interim, National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR Reanalysis, Goddard Earth Observing System Model (GEOS version 5, and EOS Aura Microwave Limb Sounder (MLS illustrate the HIRDLS GPH have a precision ranging from 2 m to 30 m and an accuracy of ±100 m. Comparisons indicate HIRDLS GPH may have a slight low bias in the tropics and a slight high bias at high latitudes. Geostrophic winds computed with HIRDLS GPH qualitatively agree with winds from other data sources including ERA-Interim, NCEP and GEOS-5.

  15. GeoSTAR - A Synthetic Aperture Microwave Sounder for Geostationary Missions

    Science.gov (United States)

    Lambrigtsen, Bjorn; Wilson, William; Tanner, Alan; Kangaslahti, Pekka

    2004-01-01

    The Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR) is a new microwave atmospheric sounder under development. It will bring capabilities similar to those now available on low-earth orbiting environmental satellites to geostationary orbit - where such capabilities have not been available. GeoSTAR will synthesize the multimeter aperture needed to achieve the required spatial resolution, which will overcome the obstacle that has prevented a GEO microwave sounder from being implemented until now. The synthetic aperture approach has until recently not been feasible, due to the high power needed to operate the on-board high-speed massively parallel processing system required for 2D-synthesis, as well as a number of system and calibration obstacles. The development effort under way at JPL, with important contributions from the Goddard Space Flight Center and the University of Michigan, is intended to demonstrate the measurement concept and retire much of the technology risk.

  16. Determination of atmospheric corrosion of coated steel surfaces by in situ infrared reflection absorption spectroscopy (IRRAS)

    International Nuclear Information System (INIS)

    Full text: Infrared reflection absorption spectroscopy (IRRAS) is a sensitive technique for measuring thin layers on metallic surfaces. The principal goal of this IRRAS study was the development of a reproducible and reliable in situ measurement procedure for the determination of corrosion of coated steel surfaces. (author)

  17. Test of far-infrared atmospheric spectroscopy using wide-band balloon-borne measurements of the upwelling radiance

    International Nuclear Information System (INIS)

    The spectroscopy of the constituents of the Earth's atmosphere that are active in the far infrared spectral region, among which the water vapour is the main one, has been validated through the analysis of wide-band nadir-looking spectra acquired with the Radiation Explorer in the Far Infrared-Prototype for Applications and Development (REFIR-PAD) Fourier transform spectroradiometer. The spectra, covering from 100 to 1400cm-1 with a 0.475cm-1 unapodized resolution, were acquired during a balloon flight performed in a tropical region in 2005. Atmospheric variables, namely water vapour and temperature vertical profiles, were retrieved from the REFIR-PAD data, and the residuals of the fitting are here critically analysed for the search of systematic effects that can be ascribed to spectroscopic errors. In the spectral interval between 150 and 600cm-1 nosignificant inconsistency is detected between the residuals and the measurement uncertainty, proving the good quality of the radiative transfer model and of the HITRAN 2004 spectroscopic database. Significant difference are instead observed when the HITRAN 2000 database is used

  18. A simplified method to estimate atmospheric water vapor using MODIS near-infrared data

    Science.gov (United States)

    Wang, Xinming; Gu, Xiaoping; Wu, Zhanping

    2016-03-01

    Atmospheric water vapor plays a significant role in the study of climate change and hydrological cycle processes. In order to acquire the accurate distribution of atmospheric water vapor which is varying with time, location, and altitude, it is necessary to monitor it at high spatial and temporal resolution. Unfortunately, it is difficult to map the spatial distribution of atmospheric water vapor due to the lack of meteorological instrumentation at adequate spatial and temporal observation scales. This paper introduces a simplified method to retrieve Precipitable Water Vapor (PWV) using the ratio of the apparent reflectance values of the 18th and 19th band of Moderate Resolution Imaging Spectroradiometer (MODIS). Compared to the EOS PWV products of the same time and area, the PWV estimated using this simplified method is closer to the radiosonde results which is considered as the true PWV value. Results reveal that this simplified method is applicable over cloud-free atmospheric conditions of the mid-latitude regions.

  19. Physical Retrieval of Surface Emissivity Spectrum from Hyperspectral Infrared Radiances

    Science.gov (United States)

    Li, Jun; Weisz, Elisabeth; Zhou, Daniel K.

    2007-01-01

    Retrieval of temperature, moisture profiles and surface skin temperature from hyperspectral infrared (IR) radiances requires spectral information about the surface emissivity. Using constant or inaccurate surface emissivities typically results in large retrieval errors, particularly over semi-arid or arid areas where the variation in emissivity spectrum is large both spectrally and spatially. In this study, a physically based algorithm has been developed to retrieve a hyperspectral IR emissivity spectrum simultaneously with the temperature and moisture profiles, as well as the surface skin temperature. To make the solution stable and efficient, the hyperspectral emissivity spectrum is represented by eigenvectors, derived from the laboratory measured hyperspectral emissivity database, in the retrieval process. Experience with AIRS (Atmospheric InfraRed Sounder) radiances shows that a simultaneous retrieval of the emissivity spectrum and the sounding improves the surface skin temperature as well as temperature and moisture profiles, particularly in the near surface layer.

  20. Further considerations of cosmic ray modulation of infra-red radiation in the atmosphere

    OpenAIRE

    Aplin, Karen; Lockwood, Mike

    2015-01-01

    Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing traditionally distinct scientific boundaries. Following the paper of Erlykin et al. (Astropart. Phys. 57--58 (2014) 26--29) we develop the interpretation of observed changes in long-wave (LW) radiation (Aplin and Lockwood, Env. Res. Letts. 8, 015026 (2013)), by taking account of cosmic ray ionisation yields and atmospheric radiative transfer. To demonstrate this, we show that the thermal stru...

  1. IIP Tropospheric Infrared Mapping Spectrometers (TIMS) measurements for widely varying terrain and atmospheric paths, example retrievals of albedos and atmospheric constituents

    Science.gov (United States)

    Rairden, R. L.; Kumer, J.; Roche, A.; Mergenthaler, J.; Chatfield, B.

    2008-12-01

    The NASA Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP) Tropospheric Infrared Mapping Spectrometers (TIMS) have been developed to demonstrate measurement capability, when deployed in space, for multi-layer retrieval of CO from spectral measurements acquired in the solar reflective (SR) region ~ 4281 to 4301 cm-1 and in the thermal InfraRed (TIR) region ~ 2110 to 2165 cm 1. Measurements in the SR of widely varying terrain types were obtained in a single data frame. The slit was projected in a vertical orientation from a balcony on the Denver University building to a scene that included the foreground at slit bottom, then on going further up the slit to a near foothill range, and finally on top side of the slit to a distant snow capped mountain range. The scene provided albedo data for various surface types including green vegetation, a bright barren spot on the foothill, and the snow cap. It also provides varying path lengths through the atmosphere, e.g., 20 km to the foothill, and 100 km to the snow cap. We'll present examples of albedo retrieved for these various features, and for gasses retrieved along the various path lengths.

  2. Potential for the use of reconstructed IASI radiances in the detection of atmospheric trace gases

    Directory of Open Access Journals (Sweden)

    N. C. Atkinson

    2010-07-01

    Full Text Available Principal component (PC analysis has received considerable attention as a technique for the extraction of meteorological signals from hyperspectral infra-red sounders such as the Infrared Atmospheric Sounding Interferometer (IASI and the Atmospheric Infrared Sounder (AIRS. In addition to achieving substantial bit-volume reductions for dissemination purposes, the technique can also be used to generate reconstructed radiances in which random instrument noise has been reduced. Studies on PC analysis of hyperspectral infrared sounder data have been undertaken in the context of numerical weather prediction, instrument monitoring and geophysical variable retrieval, as well as data compression. This study examines the potential of PC analysis for chemistry applications.

    A major concern in the use of PC analysis for chemistry is that the spectral features associated with trace gases may not be well represented in the reconstructed spectra, either due to deficiencies in the training set or due to the limited number of PC scores used in the radiance reconstruction. In this paper we show examples of reconstructed IASI radiances for several trace gases: ammonia, sulphur dioxide, methane and carbon monoxide. It is shown that care must be taken in the selection of spectra for the initial training set: an iterative technique, in which outlier spectra are added to a base training set, gives the best results. For the four trace gases examined, key features of the chemical signatures are retained in the reconstructed radiances, whilst achieving a substantial reduction in instrument noise.

    A new regional re-transmission service for IASI is scheduled to start in 2010, as part of the EUMETSAT Advanced Retransmission Service (EARS. For this EARS-IASI service it is intended to include PC scores as part of the data stream. The paper describes the generation of the reference eigenvectors for this new service.

  3. PRECISION DETERMINATION OF ATMOSPHERIC EXTINCTION AT OPTICAL AND NEAR-INFRARED WAVELENGTHS

    International Nuclear Information System (INIS)

    The science goals for future ground-based all-sky surveys, such as the Dark Energy Survey, PanSTARRS, and the Large Synoptic Survey Telescope, require calibration of broadband photometry that is stable in time and uniform over the sky to precisions of 1% or better, and absolute calibration of color measurements that are similarly accurate. This performance will need to be achieved with measurements made from multiple images taken over the course of many years, and these surveys will observe in less than ideal conditions. This paper describes a technique to implement a new strategy to directly measure variations of atmospheric transmittance at optical wavelengths and application of these measurements to calibration of ground-based observations. This strategy makes use of measurements of the spectra of a small catalog of bright 'probe' stars as they progress across the sky and back-light the atmosphere. The signatures of optical absorption by different atmospheric constituents are recognized in these spectra by their characteristic dependences on wavelength and airmass. State-of-the-art models of atmospheric radiation transport and modern codes are used to accurately compute atmospheric extinction over a wide range of observing conditions. We present results of an observing campaign that demonstrate that correction for extinction due to molecular constituents and aerosols can be done with precisions of a few millimagnitudes with this technique.

  4. Further considerations of cosmic ray modulation of infra-red radiation in the atmosphere

    CERN Document Server

    Aplin, Karen

    2015-01-01

    Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing traditionally distinct scientific boundaries. Following the paper of Erlykin et al. (Astropart. Phys. 57--58 (2014) 26--29) we develop the interpretation of observed changes in long-wave (LW) radiation (Aplin and Lockwood, Env. Res. Letts. 8, 015026 (2013)), by taking account of cosmic ray ionisation yields and atmospheric radiative transfer. To demonstrate this, we show that the thermal structure of the whole atmosphere needs to be considered along with the vertical profile of ionisation. Allowing for ionisation by all components of a cosmic ray shower and not just by the muons, reveals that the effect we have detected is certainly not inconsistent with laboratory observations of the LW absorption cross section. The analysis presented here, although very different from that of Erlykin et al., does come to the same conclusion that the events detected were not caused by individual cosmic ray primaries -- not b...

  5. Usefulness of the infrared heterodyne radiometer in remote sensing of atmospheric pollutants.

    Science.gov (United States)

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

    1971-01-01

    The application of narrow-band optical receivers to the problem of sensing atmospheric pollution is discussed. The emission/absorption lines of many major atmospheric pollutant molecules overlap the operating frequency bands of CO2 laser and CO laser heterodyne receivers. Several remote pollution sensing systems which are based upon utilization of these spectral overlaps are described, and an analysis of their potential is presented. The possibility of using other lasers (e.g.: the PbSnTe tunable diode laser) as local oscillators is also considered. Results of laboratory experiments with a CO2 laser heterodyne radiometer are presented.

  6. Desorption/ionization of biomolecules from aqueous solutions at atmospheric pressure using an infrared laser at 3 microm.

    Science.gov (United States)

    Laiko, Victor V; Taranenko, Nelli I; Berkout, Vadym D; Yakshin, Mikhail A; Prasad, Coorg R; Lee, H Sang; Doroshenko, Vladimir M

    2002-04-01

    A new atmospheric pressure (AP) infrared (IR) matrix-assisted laser desorption/ionization (MALDI) ion source was developed and interfaced with a Thermo Finnigan LCQ ion trap mass spectrometer. The source utilized a miniature all-solid-state optical parametric oscillator (OPO)-based IR laser system tunable in the lambda = 1.5-4 microm spectral range and a nitrogen ultraviolet (UV) laser (lambda = 337 nm) for use in comparative studies. The system demonstrated comparable performance at 3 microm and 337 nm wavelengths if UV matrices were used. However, AP IR-MALDI using a 3 microm wavelength showed good performance with a much broader choice of matrices including glycerol and liquid water. AP IR-MALDI mass spectra of peptides in the mass range up to 2000 Da were obtained directly from aqueous solutions at atmospheric conditions for the first time. A potential use of the new AP IR-MALDI ion source includes direct MS analysis of biological cells and tissues in a normal atmospheric environment as well as on-line coupling of mass spectrometers with liquid separation techniques. PMID:11951973

  7. HCFC-133a (CF3CH2Cl): OH rate coefficient, UV and infrared absorption spectra, and atmospheric implications

    Science.gov (United States)

    McGillen, Max R.; Bernard, François; Fleming, Eric L.; Burkholder, James B.

    2015-07-01

    HCFC-133a (CF3CH2Cl), an ozone-depleting substance, is primarily removed from the atmosphere by gas-phase reaction with OH radicals and by UV photolysis. The rate coefficient, k, for the OH + HCFC-133a reaction was measured between 233 and 379 K and is given by k(T) = (9.32 ± 0.8) × 10-13 exp(-(1296 ± 28)/T), where k(296 K) was measured to be (1.10 ± 0.02) × 10-14 (cm3 molecule-1 s-1) (2σ precision uncertainty). The HCFC-133a UV absorption spectrum was measured between 184.95 and 240 nm at 213-323 K, and a spectrum parameterization is presented. The HCFC-133a atmospheric loss processes, lifetime, ozone depletion potential, and uncertainties were evaluated using a 2-D atmospheric model. The global annually averaged steady state lifetime and ozone depletion potential (ODP) were determined to be 4.45 (4.04-4.90) years and 0.017 (±0.001), respectively, where the ranges are based solely on the 2σ uncertainty in the kinetic and photochemical parameters. The infrared absorption spectrum of HCFC-133a was measured, and its global warming potential was determined to be 380 on the 100 year time horizon.

  8. Ultrahigh-brightness, spectrally-flat, short-wave infrared supercontinuum source for long-range atmospheric applications.

    Science.gov (United States)

    Yin, Ke; Zhu, Rongzhen; Zhang, Bin; Jiang, Tian; Chen, Shengping; Hou, Jing

    2016-09-01

    Fiber based supercontinuum (SC) sources with output spectra covering the infrared atmospheric window are very useful in long-range atmospheric applications. It is proven that silica fibers can support the generation of broadband SC sources ranging from the visible to the short-wave infrared region. In this paper, we present the generation of an ultrahigh-brightness spectrally-flat 2-2.5 μm SC source in a cladding pumped thulium-doped fiber amplifier (TDFA) numerically and experimentally. The underlying physical mechanisms behind the SC generation process are investigated firstly with a numerical model which includes the fiber gain and loss, the dispersive and nonlinear effects. Simulation results show that abundant soliton pulses are generated in the TDFA, and they are shifted towards the long wavelength side very quickly with the nonlinearity of Raman soliton self-frequency shift (SSFS), and eventually the Raman SSFS process is halted due to the silica fiber's infrared loss. A spectrally-flat 2-2.5 μm SC source could be generated as the result of the spectral superposition of these abundant soliton pulses. These simulation results correspond qualitatively well to the following experimental results. Then, in the experiment, a cladding pumped large-mode-area TDFA is built for pursuing a high-power 2-2.5 μm SC source. By enhancing the pump strength, the output SC spectrum broadens to the long wavelength side gradually. At the highest pump power, the obtained SC source has a maximum average power of 203.4 W with a power conversion efficiency of 38.7%. It has a 3 dB spectral bandwidth of 545 nm ranging from 1990 to 2535 nm, indicating a power spectral density in excess of 370 mW/nm. Meanwhile, the output SC source has a good beam profile. This SC source, to the best of our knowledge, is the brightest spectrally-flat 2-2.5 μm light source ever reported. It will be highly desirable in a lot of long-range atmospheric applications, such as broad-spectrum LIDAR, free

  9. Temperature Measurements in Venus Upper Atmosphere between 2007 and 2015 from ground-based Infrared Heterodyne Spectroscopy

    Science.gov (United States)

    Krause, Pia; Wischnewski, Carolin; Sornig, Manuela; Stangier, Tobias; Sonnabend, Guido; Herrmann, Maren; Wiegand, Moritz; Kostiuk, Theodor; Livengood, Timothy

    2016-04-01

    The structure of Venus atmosphere has been the target of intense studies in the past decade. Among manifold ground based observations, the recent space mission Venus Express in particular has shed light on many open questions concerning the thermal and the dynamical behavior of its atmosphere. A comprehensive understanding of this atmospheric region is still missing. Therefore, direct measurements of atmospheric parameters on various time scales and at different locations on the planet are essential for an understanding and for the validation of global circulation models. Such observations are provided by the infrared heterodyne spectrometers THIS (University of Cologne), HIPWAC (NASA GSFC) and MILAHI (Tohoku University). These instruments fully resolve CO2 non-LTE emission lines for Doppler-wind and temperature retrievals at an pressure level of 1μbar (~110 km) by operating around 10μm. The Long- and short-term variability of daytime temperatures at the ~1μbar level from ground-based observing campaigns between 2007 to 2015 shall be presented. The observations yield a large quantity of temperature measurements at different positions on the planetary disk which allows to map a good part of the dayside of Venus. In addition a detailed study of the interesting but not well understood and only poorly investigated area close to the terminator will be given. Investigations on the general behavior of the temperature and differences between the morning and evening terminators are accomplished. Ongoing analysis of thermal variability and comparison to other observing methods and model calculations are in progress and will be included in the presentation if already available.

  10. Freshness assessment of thawed and chilled cod fillets packed in modified atmosphere using near-infrared spectroscopy

    DEFF Research Database (Denmark)

    Bøknæs, Niels; Jensen, K.N.; Andersen, Charlotte Møller;

    2002-01-01

    Near-infrared reflectance (NIR) spectra was recorded of 105 samples of cod mince prepared from chill stored thawed cod fillets of varying quality in modified atmosphere packaging (MAP). Traditional chemical, physical, microbiological and sensory quality methods developed for assessing fresh fish...... products were determined on the same cod fillets. The purpose was to evaluate the potential of NIR spectroscopy for estimating (i) frozen storage temperature, (ii) frozen storage period and (iii) chill storage period of thawed-chilled MAP Barents Sea cod fillets. Furthermore, the potential for measuring of......). Systematic differences in the NIR measurements on minced cod fillets were primarily due to the chill storage duration (days at 2 degreesC) on thawed-chilled MAP fillets. PLSR models based on wavelengths selected by a new Jack-knife method resulted in a correlation coefficient of 0.90 between measured and...

  11. Statistical distribution of the OAM states of Bessel-Gaussian-Schell infrared beams in strong turbulent atmosphere

    Science.gov (United States)

    Li, Ye; Zhang, Yixin; Wang, Donglin; Shan, Lei; Xia, Mingchao; Zhao, Yuanhang

    2016-05-01

    The effects of strong turbulence on the orbital angular momentum (OAM) states of infrared and non-diffraction beam propagation in a terrestrial atmosphere are investigated. A new probability density model for OAM states of Bessel-Gaussian-Schell beam in the paraxial and strong turbulent channel is modeled based on the modified Rytov approximation. We find that the normalization energy weight of signal OAM modes at each OAM level is approximate equivalence in strong turbulence regime, one can constitute multiple mode channels by choosing OAM modes with large energy level difference between modes to reduce mode interference, and one can utilize BGS beam with OAM modes increasing the channel capacity of optical communications.

  12. Net-Exchange parameterization of infrared radiative transfers in Venus' atmosphere

    OpenAIRE

    Eymet, Vincent; Fournier, Richard; Dufresne, Jean-Louis; Lebonnois, Sébastien; Hourdin, Frédéric; Bullock, Mark A.

    2009-01-01

    Thermal radiation within Venus atmosphere is analyzed in close details. Prominent features are identified, which are then used to design a parameterization (a highly simplified and yet accurate enough model) to be used in General Circulation Models. The analysis is based on a net exchange formulation, using a set of gaseous and cloud optical data chosen among available referenced data. The accuracy of the proposed parameterization methodology is controlled against Monte Carlo simulations, ass...

  13. Infra-red collision-induced and far-line absorption in dense CO atmospheres

    OpenAIRE

    Wordsworth, R.; Forget, F.; Eymet, Vincent

    2010-01-01

    Abstract Collision-induced absorption is of great importance to the overall radiative budget in dense CO2-rich atmospheres, but its representation in climate models remains uncertain, mainly due to a lack of accurate experimental and theoretical data. Here we compare several parameterisations of the effect, including a new one that makes use of previously unused measurements in the 1200 to 1800 cm-1 spectral range. We find that a widely used parameterisation strongly overestimates ...

  14. Further considerations of cosmic ray modulation of infra-red radiation in the atmosphere

    Science.gov (United States)

    Aplin, K. L.; Lockwood, M.

    2015-08-01

    Understanding effects of ionisation in the lower atmosphere is a new interdisciplinary area, crossing the traditionally distinct scientific boundaries between astro-particle and atmospheric physics and also requiring understanding of both heliospheric and magnetospheric influences on cosmic rays. Following the paper of Erlykin et al. (2014) we develop further the interpretation of our observed changes in long-wave (LW) radiation, Aplin and Lockwood (2013) by taking account of both cosmic ray ionisation yields and atmospheric radiative transfer. To demonstrate this, we show that the thermal structure of the whole atmosphere needs to be considered along with the vertical profile of ionisation. Allowing for, in particular, ionisation by all components of a cosmic ray shower and not just by the muons, reveals that the effect we have detected is certainly not inconsistent with laboratory observations of the LW absorption cross section. The analysis presented here, although very different from that of Erlykin et al., does come to the same conclusion that the events detected by AL were not caused by individual cosmic ray primaries - not because it is impossible on energetic grounds, but because events of the required energy are too infrequent for the 12 h-1 rate at which they were seen by the AL experiment. The present paper numerically models the effect of three different scenario changes to the primary GCR spectrum which all reproduce the required magnitude of the effect observed by AL. However, they cannot solely explain the observed delay in the peak effect which, if confirmed, would appear to open up a whole new and interesting area in the study of water oligomers and their effects on LW radiation. We argue that a technical artefact in the AL experiment is highly unlikely and that our initial observations merit both a wide-ranging follow-up experiment and more rigorous, self-consistent, three-dimensional radiative transfer modelling.

  15. A non-LTE retrieval scheme for sounding the upper atmosphere of Mars in the infrared

    Science.gov (United States)

    Lopez-Valverde, Miguel Angel; García-Comas, Maya; Funke, Bernd; Jimenez-Monferrer, Sergio; Lopez-Puertas, Manuel

    2016-04-01

    Several instruments on board Mars Express have been sounding the upper atmosphere of Mars systematically in a limb geometry in the IR part of the spectrum. Two of them in particular, OMEGA and PFS, performed emission measurements during daytime and detected the strongest IR bands of species like CO2 and CO (Piccialli et al, JGRE, submitted). Similarly on Venus, the instrument VIRTIS carried out observations of CO2 and CO bands at 2.7, 4.3 and 4.7 um at high altitudes (Gilli et al, JGRE, 2009). All these daylight atmospheric emissions respond to fluorescent situations, a case of non-local thermodynamic equilibrum conditions (non-LTE), well understood nowadays using comprehensive non-LTE theoretical models and tools (Lopez-Valverde et al., Planet. Space Sci., 2011). However, extensive exploitation of these emissions has only been done in optically thin conditions to date (Gilli et al, Icarus, 2015) or in a broad range of altitudes if in nadir geometry (Peralta et al, Apj, 2015). Within the H2020 project UPWARDS we aim at performing retrievals under non-LTE conditions including optically thick cases, like those of the CO2 and CO strongest bands during daytime in the upper atmosphere of Mars. Similar effort will also be applied eventually to Venus. We will present the non-LTE scheme used for such retrievals, based on similar efforts performed recently in studies of the Earth's upper atmosphere using data from the MIPAS instrument, on board Envisat (Funke et al., Atmos. Chem. Phys., 2009; Jurado-Navarro, PhD Thesis, Univ. Granada, 2015). Acknowledgemnt: This work is supported by the European Union's Horizon 2020 Programme under grant agreement UPWARDS-633127

  16. Analysis of functional groups in atmospheric aerosols by infrared spectroscopy: sparse methods for statistical selection of relevant absorption bands

    Science.gov (United States)

    Takahama, Satoshi; Ruggeri, Giulia; Dillner, Ann M.

    2016-07-01

    Various vibrational modes present in molecular mixtures of laboratory and atmospheric aerosols give rise to complex Fourier transform infrared (FT-IR) absorption spectra. Such spectra can be chemically informative, but they often require sophisticated algorithms for quantitative characterization of aerosol composition. Naïve statistical calibration models developed for quantification employ the full suite of wavenumbers available from a set of spectra, leading to loss of mechanistic interpretation between chemical composition and the resulting changes in absorption patterns that underpin their predictive capability. Using sparse representations of the same set of spectra, alternative calibration models can be built in which only a select group of absorption bands are used to make quantitative prediction of various aerosol properties. Such models are desirable as they allow us to relate predicted properties to their underlying molecular structure. In this work, we present an evaluation of four algorithms for achieving sparsity in FT-IR spectroscopy calibration models. Sparse calibration models exclude unnecessary wavenumbers from infrared spectra during the model building process, permitting identification and evaluation of the most relevant vibrational modes of molecules in complex aerosol mixtures required to make quantitative predictions of various measures of aerosol composition. We study two types of models: one which predicts alcohol COH, carboxylic COH, alkane CH, and carbonyl CO functional group (FG) abundances in ambient samples based on laboratory calibration standards and another which predicts thermal optical reflectance (TOR) organic carbon (OC) and elemental carbon (EC) mass in new ambient samples by direct calibration of infrared spectra to a set of ambient samples reserved for calibration. We describe the development and selection of each calibration model and evaluate the effect of sparsity on prediction performance. Finally, we ascribe

  17. Visible and infrared extinction of atmospheric aerosol in the marine and coastal environment.

    Science.gov (United States)

    Kaloshin, Gennady A

    2011-05-10

    The microphysical model Marine Aerosol Extinction Profiles (MaexPro) for surface layer marine and coastal atmospheric aerosols, which is based on long-term observations of size distributions for 0.01-100 μm particles, is presented. The fundamental feature of the model is a parameterization of amplitudes and widths for aerosol modes of the aerosol size distribution function (ASDF) as functions of fetch and wind speed. The shape of the ASDF and its dependence on meteorological parameters, altitudes above the sea level (H), fetch (X), wind speed (U), and relative humidity is investigated. The model is primarily to characterize aerosols for the near-surface layer (within 25 m). The model is also applicable to higher altitudes within the atmospheric boundary layer, where the change in the vertical profile of aerosol is not very large. In this case, it is only valid for "clean" marine environments, in the absence of air pollution or any other major sources of continental aerosols, such desert dust or smoke from biomass burning. The spectral profiles of the aerosol extinction coefficients calculated by MaexPro are in good agreement with observational data and the numerical results obtained by the well-known Navy Aerosol Model and Advanced Navy Aerosol Model codes. Moreover, MaexPro was found to be an accurate and reliable instrument for investigation of the optical properties of atmospheric aerosols. PMID:21556113

  18. Retrieving Atmospheric Temperature and Moisture Profiles from NPP CRIS/ATMS Sensors Using Crimss EDR Algorithm

    Science.gov (United States)

    Liu, X.; Kizer, S.; Barnet, C.; Dvakarla, M.; Zhou, D. K.; Larar, A. M.

    2012-01-01

    The Joint Polar Satellite System (JPSS) is a U.S. National Oceanic and Atmospheric Administration (NOAA) mission in collaboration with the U.S. National Aeronautical Space Administration (NASA) and international partners. The NPP Cross-track Infrared Microwave Sounding Suite (CrIMSS) consists of the infrared (IR) Crosstrack Infrared Sounder (CrIS) and the microwave (MW) Advanced Technology Microwave Sounder (ATMS). The CrIS instrument is hyperspectral interferometer, which measures high spectral and spatial resolution upwelling infrared radiances. The ATMS is a 22-channel radiometer similar to Advanced Microwave Sounding Units (AMSU) A and B. It measures top of atmosphere MW upwelling radiation and provides capability of sounding below clouds. The CrIMSS Environmental Data Record (EDR) algorithm provides three EDRs, namely the atmospheric vertical temperature, moisture and pressure profiles (AVTP, AVMP and AVPP, respectively), with the lower tropospheric AVTP and the AVMP being JPSS Key Performance Parameters (KPPs). The operational CrIMSS EDR an algorithm was originally designed to run on large IBM computers with dedicated data management subsystem (DMS). We have ported the operational code to simple Linux systems by replacing DMS with appropriate interfaces. We also changed the interface of the operational code so that we can read data from both the CrIMSS science code and the operational code and be able to compare lookup tables, parameter files, and output results. The detail of the CrIMSS EDR algorithm is described in reference [1]. We will present results of testing the CrIMSS EDR operational algorithm using proxy data generated from the Infrared Atmospheric Sounding Interferometer (IASI) satellite data and from the NPP CrIS/ATMS data.

  19. Scanning Mechanism of the FY-3 Microwave Humidity Sounder

    Science.gov (United States)

    Schmid, Manfred; Jing, Li; Hehr, Christian

    2010-01-01

    Astrium GmbH Germany, developed the scanning equipment for the instrument package of the MicroWave Humidity Sounder (MWHS) flying on the FY-3 meteorological satellite (FY means Feng Yun, Wind and Cloud) in a sun-synchronized orbit of 850-km altitude and at an inclination of 98.8 . The scanning mechanism rotates at variable velocity comprising several acceleration / deceleration phases during each revolution. The Scanning Mechanism contains two output shafts, each rotating a parabolic offset Antenna Reflector. The mechanism is operated in closed loop by means of redundant control electronics. MWHS is a sounding radiometer for measurement of global atmospheric water vapour profiles. An Engineering Qualification Model was developed and qualified and a first Flight Model was launched early 2008. The system is now working for more than two years successful in orbit. A second Flight Model of the Antenna Scanning Mechanism and of its associated control electronics was built and delivered to the customer for application on the follow-on spacecraft that will be launched by the end of 2010.

  20. Titan's atmosphere from Voyager infrared observations. I. The gas composition of Titan's equatorial region

    International Nuclear Information System (INIS)

    After inferring minor atmospheric-constituent abundances in Titan's equatorial region from Voyager 1 IR spectra, a stratospheric temperature profile is derived. An analysis of three different sections has yielded stratospheric mole fractions for C2H2, C2H4, C2H6, C3H4, C3H8, C4H2, HCN, and CO2; an altitude-dependent CO2 profile has been tested against observations, but no conclusive data on vertical distribution could be extracted. Emission-line formation for all minor components originates from the 1-20 mbar, or 75-200 km, pressure levels. 47 refs

  1. A portable infrared laser spectrometer for flux measurements of trace gases at the geosphere-atmosphere interface

    Science.gov (United States)

    Guimbaud, C.; Catoire, V.; Gogo, S.; Robert, C.; Chartier, M.; Laggoun-Défarge, F.; Grossel, A.; Albéric, P.; Pomathiod, L.; Nicoullaud, B.; Richard, G.

    2011-07-01

    A portable infrared laser absorption spectrometer named SPIRIT (SPectromètre Infra-Rouge In situ Troposphérique) has been set up for the simultaneous flux measurements of trace gases at the geosphere-atmosphere interface. It uses a continuous wave distributed feedback room temperature quantum cascade laser and a patented new optical multi-pass cell. The aim of SPIRIT field studies is to get a better understanding of land and water bodies to atmosphere exchange mechanisms of greenhouse gases (GHG). The analytical procedures to derive concentrations and fluxes are described, as well as the performances of the instrument under field conditions. The ability of SPIRIT to assess space and time dependence emissions of two GHG—nitrous oxide (N2O) and methane (CH4)—for different types of ecosystems is demonstrated through in situ measurements on peatland, on fertilized soil, and on water body systems. The objectives of these investigations and preliminary significant results are reported.

  2. A portable infrared laser spectrometer for flux measurements of trace gases at the geosphere–atmosphere interface

    International Nuclear Information System (INIS)

    A portable infrared laser absorption spectrometer named SPIRIT (SPectromètre Infra-Rouge In situ Troposphérique) has been set up for the simultaneous flux measurements of trace gases at the geosphere–atmosphere interface. It uses a continuous wave distributed feedback room temperature quantum cascade laser and a patented new optical multi-pass cell. The aim of SPIRIT field studies is to get a better understanding of land and water bodies to atmosphere exchange mechanisms of greenhouse gases (GHG). The analytical procedures to derive concentrations and fluxes are described, as well as the performances of the instrument under field conditions. The ability of SPIRIT to assess space and time dependence emissions of two GHG—nitrous oxide (N2O) and methane (CH4)—for different types of ecosystems is demonstrated through in situ measurements on peatland, on fertilized soil, and on water body systems. The objectives of these investigations and preliminary significant results are reported

  3. Preliminary validation of the refractivity from the new radio occultation sounder GNOS/FY-3C

    Science.gov (United States)

    Liao, Mi; Zhang, Peng; Yang, Guang-Lin; Bi, Yan-Meng; Liu, Yan; Bai, Wei-Hua; Meng, Xiang-Guang; Du, Qi-Fei; Sun, Yue-Qiang

    2016-03-01

    As a new member of the space-based radio occultation sounders, the GNOS (Global Navigation Satellite System Occultation Sounder) mounted on Fengyun-3C (FY-3C) has been carrying out atmospheric sounding since 23 September 2013. GNOS takes approximately 800 daily measurements using GPS (Global Positioning System) and Chinese BDS (BeiDou navigation satellite) signals. In this work, the atmospheric refractivity profiles from GNOS were compared with the ones obtained from the co-located ECMWF (European Centre for Medium-Range Weather Forecasts) reanalysis. The mean bias of the refractivity obtained through GNOS GPS (BDS) was found to be approximately -0.09 % (-0.04 %) from the near surface to up to 46 km. While the average standard deviation was approximately 1.81 % (1.26 %), it was as low as 0.75 % (0.53 %) in the range of 5-25 km, where best sounding results are usually achieved. Further, COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) and MetOp/ GRAS (GNSS Receiver for Atmospheric Sounding) radio occultation data were compared with the ECMWF reanalysis; the results thus obtained could be used as reference data for GNOS. Our results showed that GNOS/FY-3C meets the design requirements in terms of accuracy and precision of the sounder. It possesses a sounding capability similar to COSMIC and MetOp/GRAS in the vertical range of 0-30 km, though it needs further improvement above 30 km. Overall, it provides a new data source for the global numerical weather prediction (NWP) community.

  4. Stray light analysis of CRISTA - The Cryogenic Infrared Spectrometer and Telescope of the Atmosphere

    Science.gov (United States)

    Breault, Robert P.; Barthol, Peter

    1990-12-01

    The CRISTA experiment is designed to detect and analyze short term upper atmospheric waves and turbulence of the middle atmosphere. This paper presents two of the more intriguing stray light characteristics of the CRISTA instrument as revealed through a much more extensive stray light analysis. The two topics are the diffraction propagation from a series of edges, and the thermal loading characteristics of the outer baffles by the earth's radiation. The interesting parameters that play very complex roles relative to each other are: CRISTA's three different telescopes peer through a common aperture; the Center Telescope has an image plane shared by two spectrometers offset above or below the axis by 0.358 deg; the point source angles walk away from one slit but across the other; the wavelength bands vary from 4 microns to 70 microns; all of the imaging mirrors are simple spherical surfaces; the major source of stray light is the earth, which is only .5 deg from the optical axis; and the intermediate field stop is oversized.

  5. Validation of near infrared satellite based algorithms to relative atmospheric water vapour content over land

    International Nuclear Information System (INIS)

    This paper presents the validation results of ENVISAT MERIS and TERRA MODIS retrieval algorithms for atmospheric Water Vapour Content (WVC) estimation in clear sky condition on land. The MERIS algorithms exploits the radiance ratio of the absorbing channel at 900 nm with the almost absorption-free reference at 890 nm, while the MODIS one is based on the ratio of measurements centred at near 0.905, 0.936, and 0.94 μm with atmospheric window reflectance at 0.865 and 1.24 μm. The first test was performed in the Mediterranean area using WVC provided from both ECMWF and AERONET. As a second step, the performances of the algorithms were tested exploiting WVC computed from radio sounding (RAOBs)in the North East Australia. The different comparisons with respect to reference WVC values showed an overestimation of WVC by MODIS (root mean square error percentage greater than 20%) and an acceptable performance of MERIS algorithms (root mean square error percentage around 10%)

  6. Ozone Profile Retrieval from Satellite Observation Using High Spectral Resolution Infrared Sounding Instrument

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents a preliminary result on the retrieval of atmospheric ozone profiles using an im proved regression technique and utilizing the data from the Atmospheric InfraRed Sounder (AIRS), a hyper-spectral instrument expected to be flown on the EOS-AQUA platform in 2002. Simulated AIRS spectra were used to study the sensitivity of AIRS radiance on the tropospheric and stratospheric ozone changes, and to study the impact of various channel combinations on the ozone profile retrieval. Sensitivity study results indicate that the AIRS high resolution spectral channels between the wavenumber 650- 800 cm-1 provide very useful information to accurately retrieve tropospheric and stratospheric ozone pro files. Eigenvector decomposition of AIRS spectra indicate that no more than 100 eigenvectors are needed to retrieve very accurate ozone profiles. The accuracy of the retrieved atmospheric ozone profile from the pres ent technique and utilizing the AIRS data was compared with the accuracy obtained from current Advanced TIROS Operational Vertical Sounder (ATOVS) data aboard National Oceanic and Atmospheric Admini stration (NOAA) satellites. As expected, a comparison of retrieval results confirms that the ozone profile re trieved with the AIRS data is superior to that of ATOVS.

  7. An application of the multibeam sounder for seabed backscattering analysis

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Raju, Y.S.N.

    A theoretical analysis of vertical farfield pattern for a multibeam sounder is performed. The farfield pattern for different steered angles establish the usefulness of present multibeam arrays. An interaction effect of different steered multibeam...

  8. A Study on Retrieving Atmospheric Profiles from EOS/AIRS Observations

    Institute of Scientific and Technical Information of China (English)

    GUAN Li; ALLEN Huang; LI Jun

    2005-01-01

    The paper presents the algorithms for retrieving atmospheric temperature and moisture profiles and surface skin temperature from the high-spectral-resolution Atmospheric Infrared Sounder (AIRS) with a statistical technique based on principal component analysis. The synthetic regression coefficients for the statistical retrieval are obtained by using a fast radiative transfer model with atmospheric characteristics taken from a dataset of global radiosondes of atmospheric temperature and moisture profiles. Retrievals are evaluated by comparison with radiosonde observations and European Center of Medium-Range Weather Forecasts (ECMWF) analyses. AIRS retrievals of temperature and moisture are in general agreement with the distributions from ECMWF analysis fields and radiosonde observations, but AIRS depicts more detailed structure due to its high spectral resolution (hence, high vertical spatial resolution).

  9. TIDs in the Bottomside Ionospheric F-region Observed Near Jicamarca Using the TIDDBIT HF Doppler Sounder

    Science.gov (United States)

    Crowley, G.; Chau, J. L.

    2012-12-01

    The equatorial ionosphere is the site of complex interactions between various geospace drivers, including thermospheric winds, electric fields, and tides propagating from below. Less well known is the effect of gravity waves, and their manifestation as traveling ionospheric disturbances (TIDs). HF Doppler sounders represent a low-cost and low-maintenance solution for monitoring wave activity in the F region ionosphere. Together with modern data analysis techniques, they can provide comprehensive TID characteristics, including both horizontal and vertical TID velocities and wavelengths across the entire spectrum from periods of 1 min to over an hour. In this invited talk, we review some of the previous observations of TIDs at low latitudes, and present new observations from the TIDDBIT HF Doppler Sounder recently developed by Atmospheric and Space Technology Research Associates LLC, and deployed at Jicamarca, Peru. The completeness of the wave information obtained from the TIDDBIT system makes it possible to reconstruct the vertical displacement of isoionic contours over the 200 km horizontal dimension of the sounder array, and movies revealing the detailed shape and motion of isoionic surfaces over Peru will be shown. We demonstrate how the TID characteristics in Peru vary with season and magnetic activity. We discuss their possible impact on triggering of ionospheric bubbles and irregularities. Such information will be relevant for various operational needs involving navigation, communication, and surveillance systems. Crowley G., and F.S. Rodrigues (2012), Characteristics of Traveling Ionospheric Disturbances Observed by the TIDDBIT Sounder, Radio Sci., doi:10.1029/2011RS004959.

  10. High spectral resolution fourier transform infrared instruments for the Atmospheric Radiation Measurement Program

    International Nuclear Information System (INIS)

    Major accomplishments of the Atmospheric Emitted Radiance Interferometer (AERI) Instrument Development Program (IDP) effort have been to (1) develop and extensively test a new radiometric calibration subsystem with improved accuracy and robustness; (2) interact with Bomem, Inc., leading to the development of a two-channel interferometer with the required software characteristics; (3) develop new operational control software and network interfaces; (4) develop new analysis techniques to handle the complete calibration, including a detector nonlinearity correction, wavelength scale standardization, and a finite field-of-view correction; (5) integrate the required hardware, operational control software, and analysis software into a complete system which interfaces to the CART data system and operates remotely; and (6) perform extensive field testing of the AERI system prototype

  11. An Algorithm For Climate-Quality Atmospheric Profiling Continuity From EOS Aqua To Suomi-NPP

    Science.gov (United States)

    Moncet, J. L.

    2015-12-01

    We will present results from an algorithm that is being developed to produce climate-quality atmospheric profiling earth system data records (ESDRs) for application to hyperspectral sounding instrument data from Suomi-NPP, EOS Aqua, and other spacecraft. The current focus is on data from the S-NPP Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) instruments as well as the Atmospheric InfraRed Sounder (AIRS) on EOS Aqua. The algorithm development at Atmospheric and Environmental Research (AER) has common heritage with the optimal estimation (OE) algorithm operationally processing S-NPP data in the Interface Data Processing Segment (IDPS), but the ESDR algorithm has a flexible, modular software structure to support experimentation and collaboration and has several features adapted to the climate orientation of ESDRs. Data record continuity benefits from the fact that the same algorithm can be applied to different sensors, simply by providing suitable configuration and data files. The radiative transfer component uses an enhanced version of optimal spectral sampling (OSS) with updated spectroscopy, treatment of emission that is not in local thermodynamic equilibrium (non-LTE), efficiency gains with "global" optimal sampling over all channels, and support for channel selection. The algorithm is designed for adaptive treatment of clouds, with capability to apply "cloud clearing" or simultaneous cloud parameter retrieval, depending on conditions. We will present retrieval results demonstrating the impact of a new capability to perform the retrievals on sigma or hybrid vertical grid (as opposed to a fixed pressure grid), which particularly affects profile accuracy over land with variable terrain height and with sharp vertical structure near the surface. In addition, we will show impacts of alternative treatments of regularization of the inversion. While OE algorithms typically implement regularization by using background estimates from

  12. Planetary protection for Europa radar sounder antenna

    Science.gov (United States)

    Aaron, Kim M.; Moussessian, Alina; Newlin, Laura E.; Willis, Paul B.; Chen, Fei; Harcke, Leif J.; Chapin, Elaine; Jun, Insoo; Gim, Yonggyu; McEachen, Michael; Allen, Scotty; Kirchner, Donald; Blankenship, Donald

    2016-05-01

    The potential for habitability puts stringent requirements on planetary protection for a mission to Europa. A long-wavelength radar sounder with a large antenna is one of the proposed instruments for a future Europa mission. The size and construction of radar sounding antennas make the usual methods of meeting planetary protection requirements challenging. This paper discusses a viable planetary protection scheme for an antenna optimized for Europa radar sounding. The preferred methodology for this antenna is exposure to 100 kGy (10 Mrad) in water of gamma radiation using a Cobalt-60 source for both bulk and surface sterilization and exposure to vapor hydrogen peroxide for surface treatment for possible recontamination due to subsequent handling. For the boom-supported antenna design, selected tests were performed to confirm the suitability of these treatment methods. A portion of a coilable boom residual from an earlier mission was irradiated and its deployment repeatability confirmed with no degradation. Elasticity was measured of several fiberglass samples using a four-point bending test to confirm that there was no degradation due to radiation exposure. Vapor hydrogen peroxide treatment was applied to the silver-coated braid used as the antenna radiating element as it was the material most likely to be susceptible to oxidative attack under the treatment conditions. There was no discernable effect. These tests confirm that the radar sounding antenna for a Europa mission should be able tolerate the proposed sterilization methods.

  13. Modeling angular-dependent spectral emissivity of snow and ice in the thermal infrared atmospheric window.

    Science.gov (United States)

    Hori, Masahiro; Aoki, Teruo; Tanikawa, Tomonori; Hachikubo, Akihiro; Sugiura, Konosuke; Kuchiki, Katsuyuki; Niwano, Masashi

    2013-10-20

    A model of angular-dependent emissivity spectra of snow and ice in the 8-14 μm atmospheric window is constructed. Past field research revealed that snow emissivity varies depending on snow grain size and the exitance angle. Thermography images acquired in this study further revealed that not only welded snow particles such as sun crust, but also disaggregated particles such as granular snow and dendrite crystals exhibit high reflectivity on their crystal facets, even when the bulk snow surface exhibits blackbody-like behavior as a whole. The observed thermal emissive behaviors of snow particles suggest that emissivity of the bulk snow surface can be expressed by a weighted sum of two emissivity components: those of the specular and blackbody surfaces. Based on this assumption, a semi-empirical emissivity model was constructed; it is expressed by a linear combination of specular and blackbody surfaces' emissivities with a weighting parameter characterizing the specularity of the bulk surface. Emissivity spectra calculated using the model succeeded in reproducing the past in situ measured directional spectra of various snow types by employing a specific weighting parameter for each snow type. PMID:24216578

  14. Measurements of the D/H ratio in planetary atmospheres by ground based infrared spectroscopy

    International Nuclear Information System (INIS)

    We have carried out a systematic study of deuterium in the solar system using the molecules CH3D and HDO as our tracers. For the outer solar system, we obtained ground-based spectra of Saturn, Uranus, Neptune and Titan in the region of CH3D absorptions near 1.6 microns, with the facilities at Kitt Peak National Observatory, in Arizona, and the Canada-France-Hawaii telescope in Hawaii. The analyses of these spectra required extensive high-resolution laboratory studies of both CH4 and CH3D. For the terrestrial planets, we recorded the spectrum of Mars in the region of HDO absorption near 3.7 microns from the high-altitude Canada-France-Hawaii telescope on Mauna Kea, Hawaii, where telluric HDO is minimized. A similar study of Venus is underway. The values of D/H derived from these investigations are used to constrain models for the origin and evolution of the various atmospheres

  15. Infrared Spectra of N_2-BROADENED 13CH_4 at Titan Atmospheric Temperatures

    Science.gov (United States)

    Smith, M. A. H.; Sung, K.; Brown, L. R.; Crawford, T. J.; Mantz, A. W.; Devi, V. Malathy; Benner, D. Chris

    2010-06-01

    High-resolution spectra of the ν_4 fundamental band of 13CH_4 broadened by N_2 at temperatures relevant to the atmosphere of Titan (80 K to 296 K) have been recorded using new temperature-controlled absorption cells installed in the sample compartment of a Bruker (IFS-125HR) Fourier Transform spectrometer (FTS) at the Jet Propulsion Laboratory (JPL). Details of the cells and spectrometer performance have been discussed in the previous talk. Early analysis of these spectra using multispectrum fitting has determined half widths, pressure-induced shifts, line mixing parameters and their temperature dependences for R-branch transitions from R(0) through R(6). In addition to the initial R(2) study mentioned in the previous talk, the analysis for the other J-manifolds examined in detail whether or not the N_2-broadened half width coefficients follow the simple power-law temperature-dependence over the entire temperature range from 80 K to 296 K. The results are compared with other published measurements of N_2-broadened methane parameters at low temperatures. A. W. Mantz et al., Closed-cycle He-cooled absorption cells designed for a Bruker IFS-125HR: First results between 79 K and 297 K, this session. Research described in this paper was performed at Connecticut College, the College of William and Mary, NASA Langley Research Center and the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.

  16. Microwave Limb Sounder/El Nino Watch - February thru December, 1997

    Science.gov (United States)

    1998-01-01

    This series of six images shows the movement of atmospheric water vapor over the Pacific Ocean during the formation of the 1997 El Nino condition. Higher than normal ocean water temperatures increase the rate of evaporation and the resulting warm moist air rises into the atmosphere altering global weather patterns. Data obtained by the Microwave Limb Sounder (MLS) on NASA's Upper Atmosphere Research Satellite (UARS), from late February 1997 to late December 1997, show the movement from the western Pacific to the eastern Pacific of high levels of water vapor (red) at 10 kilometers (6 miles) above the surface. Areas of unusually drier air (blue) appear over Indonesia. December 1997 data also show a rapid increase of water vapor off the coast of South America, the result of very high water temperatures in that region.

  17. ARIEL - The Atmospheric Remote-sensing Infrared Exoplanet Large-survey

    Science.gov (United States)

    Eccleston, P.; Tinetti, G.

    2015-10-01

    More than 1,000 extrasolar systems have been discovered, hosting nearly 2,000 exoplanets. Ongoing and planned ESA and NASA missions from space such as GAIA, Cheops, PLATO, K2 and TESS, plus ground based surveys, will increase the number of known systems to tens of thousands. Of all these exoplanets we know very little; i.e. their orbital data and, for some of these, their physical parameters such as their size and mass. In the past decade, pioneering results have been obtained using transit spectroscopy with Hubble, Spitzer and ground-based facilities, enabling the detection of a few of the most abundant ionic, atomic and molecular species and to constrain the planet's thermal structure. Future general purpose facilities with large collecting areas will allow the acquisition of better exoplanet spectra, compared to the currently available, especially from fainter targets. A few tens of planets will be observed with JWST and E-ELT in great detail. A breakthrough in our understanding of planet formation and evolution mechanisms will only happen through the observation of the planetary bulk and atmospheric composition of a statistically large sample of planets. This requires conducting spectroscopic observations covering simultaneously a broad spectral region from the visible to the mid-IR. It also requires a dedicated space mission with the necessary photometric stability to perform these challenging measurements and sufficient agility to observe multiple times ~500 exoplanets over 3.5 years. The ESA Cosmic Vision M4 mission candidate ARIEL is designed to accomplish this goal and will provide a complete, statistically significant sample of gas-giants, Neptunes and super-Earths with temperatures hotter than 600K, as these types of planets will allow direct observation of their bulk properties, enabling us to constrain models of planet formation and evolution. The ARIEL consortium currently includes academic institutes and industry from eleven countries in Europe; the

  18. Improved total atmospheric water vapour amount determination from near-infrared filter measurements with sun photometers

    Directory of Open Access Journals (Sweden)

    F. Mavromatakis

    2007-05-01

    Full Text Available In this work we explore the effect of the contribution of the solar spectrum to the recorded signal in wavelengths outside the typical 940-nm filter's bandwidth. We use gaussian-shaped filters as well as actual filter transmission curves to study the implications imposed by the non-zero out-of-band contribution to the coefficients used to derive precipitable water from the measured water vapour band transmittance. The moderate-resolution SMARTS radiative transfer code is used to predict the incident spectrum outside the filter bandpass for different atmospheres, solar geometries and aerosol optical depths. The high-resolution LBLRTM radiative transfer code is used to calculate the water vapour transmittance in the 940 nm band. The absolute level of the out-of-band transmittance has been chosen to range from 10−6 to 10−4, and typical response curves of commercially available silicon photodiodes are included into the calculations. It is shown that if the out-of-band transmittance effect is neglected, as is generally the case, then the derived columnar water vapour is systematically underestimated by a few percents. The actual error depends on the specific out-of-band transmittance, optical air mass of observation and water vapour amount. We apply published parameterized transmittance functions to determine the filter coefficients. We also introduce an improved, three-parameter, fitting function that can describe the theoretical data accurately, with significantly less residual effects than with the existing functions. Further investigations will use experimental data from field campaigns to validate these findings.

  19. Atmospheric Profile Retrieval with AIRS Data and Validation at the ARM CART Site

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The physical retrieval algorithm of atmospheric temperature and moisture distribution from the Atmospheric InfraRed Sounder (AIRS) radiances is presented. The retrieval algorithm is applied to AIRS clear-sky radiance measurements. The algorithm employs a statistical retrieval followed by a subsequent nonlinear physical retrieval. The regression coefficients for the statistical retrieval are derived from a dataset of global radiosonde observations (RAOBs) comprising atmospheric temperature, moisture, and ozone profiles. Evaluation of the retrieved profiles is performed by a comparison with RAOBs from the Atmospheric Radiation Measurement (ARM) Program Cloud And Radiation Testbed (CART) in Oklahoma,U. S. A.. Comparisons show that the physically-based AIRS retrievals agree with the RAOBs from the ARM CART site with a Root Mean Square Error (RMSE) of 1 K on average for temperature profiles above 850 hPa, and approximately 10% on average for relative humidity profiles. With its improved spectral resolution, AIRS depicts more detailed structure than the current Geostationary Operational Environmental Satellite (GOES) sounder when comparing AIRS sounding retrievals with the operational GOES sounding products.

  20. Physical, meteorological, and other data from surface sensors and CTD casts in the Bering Sea from the SEA SOUNDER as part of the Outer Continental Shelf Environmental Assessment Program (OCSEAP) from 08 July 1977 to 29 July 1977 (NODC Accession 7700848)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Physical, meteorological, and other data were collected from surface sensors and CTD casts in the Bering Sea from the SEA SOUNDER. Data were collected by the...

  1. The National Polar-orbiting Operational Environmental Satellite System: Capabilities for Atmospheric Remote Sensing for NWP and Climate -- Moving Towards a Global Earth Observation System of Systems

    Science.gov (United States)

    Mango, S. A.; Hinnant, F.; Hoffman, C. W.; Smehil, D. L.; Schneider, S. R.; Simione, S.; Needham, B.; Stockton, D.

    2005-12-01

    Over the last decade, the tri-agency Integrated Program Office (IPO), comprised of the National Oceanic and Atmospheric Administration (NOAA), the Department of Defense (DoD), and the National Aeronautics and Space Administration (NASA), has been managing the development of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). Once operational later this decade, NPOESS will replace NOAA's Polar-orbiting Operational Environmental Satellites (POES) and DoD's Defense Meteorological Satellite Program (DMSP) systems. The IPO, through its Acquisition and Operations contractor, Northrop Grumman, will launch NPOESS spacecraft into three orbital planes to provide a single, national system capable of satisfying both civil and national security requirements for space-based, remotely sensed environmental data. With the development of NPOESS, we are evolving the existing "weather" satellites into integrated environmental observing systems by expanding our capabilities to observe, assess, and predict the total Earth system - ocean, atmosphere, land, and the space environment. The NPOESS will enable more accurate short-term weather forecasts and severe storm warnings and improved monitoring of atmospheric phenomena. NPOESS will also provide continuity of critical data for monitoring, understanding, and predicting climate change and assessing the impacts of climate change on seasonal and longer time scales. For these purposes, the NPOESS Integrated Program Office [IPO] is developing a suite of advanced, atmospheric sounding/probing instruments as a major part of the next generation meteorological, environmental and climate operational satellite system in polar, low earth orbit [LEO]. The IPO is developing the CrIS, Cross-track Infrared Sounder, an Ozone Mapping & Profiler Suite [OMPS]and a Visible and Infrared Imager and Radiometer Suite [VIIRS] and NASA is developing an Advanced Technology Microwave Sounder [ATMS]. These four instruments will be key

  2. Characterizing a Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS for measurements of atmospheric ammonia

    Directory of Open Access Journals (Sweden)

    R. A. Ellis

    2009-12-01

    Full Text Available A compact, fast-response Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS for measurements of ammonia has been evaluated under both laboratory and field conditions. Absorption of radiation from a pulsed, thermoelectrically cooled QC laser occurs at reduced pressure in a 0.5 L multiple pass absorption cell with an effective path length of 76 m. Detection is achieved using a thermoelectrically cooled Mercury Cadmium Telluride (HgCdTe infrared detector. A novel sampling inlet was used, consisting of a short, heated, quartz tube with a hydrophobic coating to minimize the adsorption of ammonia to surfaces. The inlet contains a critical orifice that reduces the pressure, a virtual impactor for separation of particles, and additional ports for delivering ammonia-free background air and calibration gas standards. This instrument has been found to have a detection limit of 0.23 ppb at 1 Hz. The sampling technique has been compared to the results of a conventional lead salt Tunable Diode Laser Absorption Spectrometer (TDLAS during a laboratory intercomparison. The effect of humidity and heat on the surface interaction of ammonia with sample tubing was investigated at mixing ratios ranging from 30–1000 ppb. Humidity was seen to worsen the ammonia time response and considerable improvement was observed when using a heated sampling line. A field intercomparison of the QC-TILDAS with a modified Thermo 42CTL chemiluminescence based analyzer was also performed at Environment Canada's Centre for Atmospheric Research Experiments (CARE in the rural town of Egbert, ON between May–July 2008. Background tests and calibrations using two different permeation tube sources and an ammonia gas cylinder were regularly carried out throughout the study. Results indicate a very good correlation with 1 min time resolution (R2=0.93 between the two instruments at the beginning of the study, when regular background

  3. Characterizing a Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS for measurements of atmospheric ammonia

    Directory of Open Access Journals (Sweden)

    R. A. Ellis

    2010-03-01

    Full Text Available A compact, fast-response Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS for measurements of ammonia (NH3 has been evaluated under both laboratory and field conditions. Absorption of radiation from a pulsed, thermoelectrically cooled QC laser occurs at reduced pressure in a 0.5 L multiple pass absorption cell with an effective path length of 76 m. Detection is achieved using a thermoelectrically-cooled Mercury Cadmium Telluride (HgCdTe infrared detector. A novel sampling inlet was used, consisting of a short, heated, quartz tube with a hydrophobic coating to minimize the adsorption of NH3 to surfaces. The inlet contains a critical orifice that reduces the pressure, a virtual impactor for separation of particles, and additional ports for delivering NH3-free background air and calibration gas standards. The level of noise in this instrument has been found to be 0.23 ppb at 1 Hz. The sampling technique has been compared to the results of a conventional lead salt Tunable Diode Laser Absorption Spectrometer (TDLAS during a laboratory intercomparison. The effect of humidity and heat on the surface interaction of NH3 with sample tubing was investigated at mixing ratios ranging from 30–1000 ppb. Humidity was seen to worsen the NH3 time response and considerable improvement was observed when using a heated sampling line. A field intercomparison of the QC-TILDAS with a modified Thermo 42CTL chemiluminescence-based analyzer was also performed at Environment Canada's Centre for Atmospheric Research Experiments (CARE in the rural town of Egbert, ON between May–July 2008. Background tests and calibrations using two different permeation tube sources and an NH3 gas cylinder were regularly carried out throughout the study. Results indicate a very good correlation at 1 min time resolution (R2 = 0.93 between the two instruments at the

  4. Stratospheric and mesospheric pressure-temperature profiles from rotational analysis of CO2 lines in atmospheric trace molecule spectroscopy/ATLAS 1 infrared solar occultation spectra

    Science.gov (United States)

    Stiller, G. P.; Gunson, M. R.; Lowes, L. L.; Abrams, M. C.; Raper, O. F.; Farmer, C. B.; Zander, R.; Rinsland, C. P.

    1995-01-01

    A simple, classical, and expedient method for the retrieval of atmospheric pressure-temperature profiles has been applied to the high-resolution infrared solar absorption spectra obtained with the atmospheric trace molecule spectroscopy (ATMOS) instrument. The basis for this method is a rotational analysis of retrieved apparent abundances from CO2 rovibrational absorption lines, employing existing constituent concentration retrieval software used in the analysis of data returned by ATMOS. Pressure-temperature profiles derived from spectra acquired during the ATLAS 1 space shuttle mission of March-April 1992 are quantitatively evaluated and compared with climatological and meteorological data as a means of assessing the validity of this approach.

  5. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    Energy Technology Data Exchange (ETDEWEB)

    Wiesinger, R. [Institute of Science and Technology in Art, Academy of Fine Arts, 1010 Vienna (Austria); Schade, U. [Helmholtz-Zentrum für Materialien und Energy GmbH, Elektronenspeicherring BESSY II, 12489 Berlin (Germany); Kleber, Ch. [Centre for Electrochemical Surface Technology, 2700 Wiener Neustadt (Austria); Schreiner, M. [Institute of Science and Technology in Art, Academy of Fine Arts, 1010 Vienna (Austria); Institute for Chemical Technologies and Analytics, Vienna University of Technology, 1060 Vienna (Austria)

    2014-06-15

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  6. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    Science.gov (United States)

    Wiesinger, R.; Schade, U.; Kleber, Ch.; Schreiner, M.

    2014-06-01

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations.

  7. An experimental set-up to apply polarization modulation to infrared reflection absorption spectroscopy for improved in situ studies of atmospheric corrosion processes

    International Nuclear Information System (INIS)

    A new set-up for improved monitoring of atmospheric corrosion processes in situ and in real-time is presented. To characterize chemical structures of thin films on metal surfaces surface sensitive analytical techniques are required. One possible technique is Infrared Reflection Absorption Spectroscopy (IRRAS) which has become an established method to investigate surface corrosion films of thicknesses less than 200 nm. However, there are limitations related to the sensitivity of these measurements, in case of investigating ultrathin films or absorption bands of interest, surface species are superimposed by atmospheric background absorption, which changes during in situ measurements in ambient atmospheres. These difficulties of in situ surface reflection measurements can be eliminated by availing the polarization selectivity of adsorbed surface species. At grazing angles of incidence the absorption of p-polarized infrared radiation by thin surface films on metals is enhanced, while the absorption of s-polarized light by this film is nearly zero. This different behavior of the polarization properties leads to strong selection rules at the surface and can therefore be used to identify molecules adsorbed on metal surfaces. Polarization Modulation (PM) of the infrared (IR) light takes advantage of this disparity of polarization on sample surfaces and in combination with IRRAS yielding a very sensitive and surface-selective method for obtaining IR spectra of ultra-thin films on metal surfaces. An already existing in situ IRRAS/Quartz Crystal Microbalance weathering cell was combined with PM and evaluated according to its applicability to study in situ atmospheric corrosion processes. First real-time measurements on silver samples exposed to different atmospheres were performed showing the advantage of PM-IRRAS compared to conventional IRRAS for such investigations

  8. Characterization of artifacts introduced by the empirical volcano-scan atmospheric correction commonly applied to CRISM and OMEGA near-infrared spectra

    Science.gov (United States)

    Wiseman, S. M.; Arvidson, R. E.; Wolff, M. J.; Smith, M. D.; Seelos, F. P.; Morgan, F.; Murchie, S. L.; Mustard, J. F.; Morris, R. V.; Humm, D.; McGuire, P. C.

    2016-05-01

    The empirical 'volcano-scan' atmospheric correction is widely applied to martian near infrared CRISM and OMEGA spectra between ∼1000 and ∼2600 nm to remove prominent atmospheric gas absorptions with minimal computational investment. This correction method employs division by a scaled empirically-derived atmospheric transmission spectrum that is generated from observations of the martian surface in which different path lengths through the atmosphere were measured and transmission calculated using the Beer-Lambert Law. Identifying and characterizing both artifacts and residual atmospheric features left by the volcano-scan correction is important for robust interpretation of CRISM and OMEGA volcano-scan corrected spectra. In order to identify and determine the cause of spectral artifacts introduced by the volcano-scan correction, we simulated this correction using a multiple scattering radiative transfer algorithm (DISORT). Simulated transmission spectra that are similar to actual CRISM- and OMEGA-derived transmission spectra were generated from modeled Olympus Mons base and summit spectra. Results from the simulations were used to investigate the validity of assumptions inherent in the volcano-scan correction and to identify artifacts introduced by this method of atmospheric correction. We found that the most prominent artifact, a bowl-shaped feature centered near 2000 nm, is caused by the inaccurate assumption that absorption coefficients of CO2 in the martian atmosphere are independent of column density. In addition, spectral albedo and slope are modified by atmospheric aerosols. Residual atmospheric contributions that are caused by variable amounts of dust aerosols, ice aerosols, and water vapor are characterized by the analysis of CRISM volcano-scan corrected spectra from the same location acquired at different times under variable atmospheric conditions.

  9. Characterization of Artifacts Introduced by the Empirical Volcano-Scan Atmospheric Correction Commonly Applied to CRISM and OMEGA Near-Infrared Spectra

    Science.gov (United States)

    Wiseman, S.M.; Arvidson, R.E.; Wolff, M. J.; Smith, M. D.; Seelos, F. P.; Morgan, F.; Murchie, S. L.; Mustard, J. F.; Morris, R. V.; Humm, D.; McGuire, P. C.

    2014-01-01

    The empirical volcano-scan atmospheric correction is widely applied to Martian near infrared CRISM and OMEGA spectra between 1000 and 2600 nanometers to remove prominent atmospheric gas absorptions with minimal computational investment. This correction method employs division by a scaled empirically-derived atmospheric transmission spectrum that is generated from observations of the Martian surface in which different path lengths through the atmosphere were measured and transmission calculated using the Beer-Lambert Law. Identifying and characterizing both artifacts and residual atmospheric features left by the volcano-scan correction is important for robust interpretation of CRISM and OMEGA volcano scan corrected spectra. In order to identify and determine the cause of spectral artifacts introduced by the volcano-scan correction, we simulated this correction using a multiple scattering radiative transfer algorithm (DISORT). Simulated transmission spectra that are similar to actual CRISM- and OMEGA-derived transmission spectra were generated from modeled Olympus Mons base and summit spectra. Results from the simulations were used to investigate the validity of assumptions inherent in the volcano-scan correction and to identify artifacts introduced by this method of atmospheric correction. We found that the most prominent artifact, a bowl-shaped feature centered near 2000 nanometers, is caused by the inaccurate assumption that absorption coefficients of CO2 in the Martian atmosphere are independent of column density. In addition, spectral albedo and slope are modified by atmospheric aerosols. Residual atmospheric contributions that are caused by variable amounts of dust aerosols, ice aerosols, and water vapor are characterized by the analysis of CRISM volcano-scan corrected spectra from the same location acquired at different times under variable atmospheric conditions.

  10. Echothermometry: The potential role of echo sounders in ocean acoustic thermometry

    NARCIS (Netherlands)

    Ainslie, M.A.; Dybedal, J.; Kinneging; Lam, F.P.A.; Simons, D.G.; Snellen, M.

    2005-01-01

    The sensitivity of sound speed to temperature makes it possible to use an echo sounder as a thermometer, provided that the salinity and water depth are known with sufficient precision. Could ‘echothermometry’ – i.e., the use of an echo sounder, or a network of echo sounders, to measure temperature i

  11. Testing Model Atmospheres for Young Very Low Mass Stars and Brown Dwarfs in the Infrared: Evidence for Significantly Underestimated Dust Opacities

    CERN Document Server

    Tottle, Jonathan

    2014-01-01

    We test state-of-the-art model atmospheres for young very low-mass stars and brown dwarfs in the infrared, by comparing the predicted synthetic photometry over 1.2-24 {\\mu}m to the observed photometry of M-type spectral templates in star-forming regions. We find that (1) in both early and late young M types, the model atmospheres imply effective temperatures (Teff) several hundred Kelvin lower than predicted by the standard Pre-Main Sequence spectral type-Teff conversion scale (where the latter is based on theoretical evolutionary models). It is only in the mid-M types that the two temperature estimates agree. (2) The Teff discrepancy in the early M types (corresponding to stellar masses above 0.6 Msol at a few Myr) probably arises from remaining uncertainties in the treatment of atmospheric convection. The agreement in the mid-M types implies a reasonably good atmospheric modeling of H2O opacities, which dominate in the infrared at these spectral types. Conversely, the Teff discrepancy in the late M types is...

  12. Strategy for high-accuracy-and-precision retrieval of atmospheric methane from the mid-infrared FTIR network

    Directory of Open Access Journals (Sweden)

    R. Sussmann

    2011-09-01

    Full Text Available We present a strategy (MIR-GBM v1.0 for the retrieval of column-averaged dry-air mole fractions of methane (XCH4 with a precision <0.3% (1-σ diurnal variation, 7-min integration and a seasonal bias <0.14% from mid-infrared ground-based solar FTIR measurements of the Network for the Detection of Atmospheric Composition Change (NDACC, comprising 22 FTIR stations. This makes NDACC methane data useful for satellite validation and for the inversion of regional-scale sources and sinks in addition to long-term trend analysis. Such retrievals complement the high accuracy and precision near-infrared observations of the younger Total Carbon Column Observing Network (TCCON with time series dating back 15 years or so before TCCON operations began.

    MIR-GBM v1.0 is using HITRAN 2000 (including the 2001 update release and 3 spectral micro windows (2613.70–2615.40 cm−1, 2835.50–2835.80 cm−1, 2921.00–2921.60 cm−1. A first-order Tikhonov constraint is applied to the state vector given in units of per cent of volume mixing ratio. It is tuned to achieve minimum diurnal variation without damping seasonality. Final quality selection of the retrievals uses a threshold for the goodness of fit (χ2 < 1 as well as for the ratio of root-mean-square spectral noise and information content (<0.15%. Column-averaged dry-air mole fractions are calculated using the retrieved methane profiles and four-times-daily pressure-temperature-humidity profiles from National Center for Environmental Prediction (NCEP interpolated to the time of measurement.

    MIR-GBM v1.0 is the optimum of 24 tested retrieval strategies (8 different spectral micro-window selections, 3 spectroscopic line lists: HITRAN 2000, 2004, 2008. Dominant errors of the non-optimum retrieval strategies are systematic HDO/H2O-CH4 interference errors leading to a seasonal bias up to ≈5%. Therefore interference

  13. Strategy for high-accuracy-and-precision retrieval of atmospheric methane from the mid-infrared FTIR network

    Directory of Open Access Journals (Sweden)

    R. Sussmann

    2011-05-01

    Full Text Available We present a strategy (MIR-GBM v1.0 for the retrieval of column-averaged dry-air mole fractions of methane (XCH4 with a precision <0.3 % (1-σ diurnal variation, 7-min integration and a seasonal bias <0.14 % from mid-infrared ground-based solar FTIR measurements of the Network for the Detection of Atmospheric Composition Change (NDACC, comprising 22 FTIR stations. This makes NDACC methane data useful for satellite validation and for the inversion of regional-scale sources and sinks in addition to long-term trend analysis. Such retrievals complement the high accuracy and precision near-infrared observations of the younger Total Carbon Column Observing Network (TCCON with time series dating back 15 yr or so before TCCON operations began.

    MIR-GBM v1.0 is using HITRAN 2000 (including the 2001 update release and 3 spectral micro windows (2613.70–2615.40 cm−1, 2835.50–2835.80 cm−1, 2921.00–2921.60 cm−1. A first-order Tikhonov constraint is applied to the state vector given in units of per cent of volume mixing ratio. It is tuned to achieve minimum diurnal variation without damping seasonality. Final quality selection of the retrievals uses a threshold for the ratio of root-mean-square spectral residuals and information content (<0.15 %. Column-averaged dry-air mole fractions are calculated using the retrieved methane profiles and four-times-daily pressure-temperature-humidity profiles from National Center for Environmental Prediction (NCEP interpolated to the time of measurement.

    MIR-GBM v1.0 is the optimum of 24 tested retrieval strategies (8 different spectral micro-window selections, 3 spectroscopic line lists: HITRAN 2000, 2004, 2008. Dominant errors of the non-optimum retrieval strategies are HDO/H2O-CH4 interference errors (seasonal bias up to ≈4 %. Therefore interference errors have been quantified at 3 test sites covering clear-sky integrated

  14. A comparison of minor trace gas retrievals from the Tropospheric Emission Spectrometer (TES) and the Infrared Atmospheric Sounding Interferometer (IASI)

    Science.gov (United States)

    Cady-Pereira, K. E.; Shephard, M. W.; Henze, D. K.; Millet, D. B.; Gombos, D.; Van Damme, M.; Clarisse, L.; Coheur, P. F.; Pommier, M.; Clerbaux, C.

    2014-12-01

    The advent of hyperspectral infrared instruments orbiting the Earth has allowed for detecting and measuring numerous trace gas species that play important roles in atmospheric chemistry and impact air quality, but for which there is a dearth of information on their distribution and temporal variability. Here we will present global and regional comparisons of measurements from the NASA TES and the European MetOp IASI instruments of three of these gases: ammonia (NH3), formic acid (HCOOH) and methanol (CH3OH). Ammonia is highly reactive and thus very variable in space and time, while the sources and sinks of methanol and formic acid are poorly quantified: thus space-based measurements have the potential of significantly increasing our knowledge of the emissions and distributions of these gases. IASI and TES have many similarities but some significant differences. TES has significantly higher spectral resolution (0.06 cm-1), and its equator crossing times are ~1:30 am and 1:30 pm, local time, while IASI has lower resolution (0.5 cm-1) and an earlier equator crossing time (9:30 am and 9:30 pm), which leads to lower thermal contrast; however IASI provides much greater temporal and spatial coverage due to its cross-track scanning. Added to the instrumental differences are the differences in retrieval algorithms. The IASI team uses simple but efficient methods to estimate total column amounts of the species above, while the TES team performs full optimal estimation retrievals. We will compare IASI and TES total column measurements averaged on a 2.5x2.5 degree global grid for each month in 2009, and we will examine the seasonal cycle in some regions of interest, such as South America, eastern China, and the Midwest and the Central Valley in the US. In regions where both datasets are in agreement this analysis will provide confidence that the results are robust and reliable. In regions where there is disagreement we will look for the causes of the discrepancies, which will

  15. Estimation of planetary surface roughness by HF sounder observation

    Science.gov (United States)

    Kobayashi, T.; Ono, T.

    Japanese Martian exploration project "Nozomi" was to carry out several science missions. Plasma Wave Sounder, one of those onboard missions, was an HF sounder to study Martian plasma environment, and Martian surface with the altimetry mode (Oya and Ono, 1998) as well. The altimetry mode observation was studied by means of computer simulations utilizing the KiSS code which had been originally designed to simulate the SELENE Lunar Radar Sounder, a spaceborne HF GPR, based on Kirchhoff approximation theory (Kobayashi, Oya and Ono, 2002). We found an empirical power law for the standard deviation of observed altitudes over Gaussian random rough surfaces: it varies in proportion to the square of the RMS gradient of the surface √{2} hRMS{λ_0, where hRMS and λ_0 are the RMS height of the surface and the correlation distance of the surface, respectively. We applied Geometrical optics to understand this empirical power law, and derived a square power law for the standard deviation of the observed altitude. Our Geometrical optics model assumed the followings: 1) the observed surface is a Gaussian random rough surface, 2) the mean surface is a flat horizontal plane, 3) the observed surface echo is the back scattering echoes, 4) the observed altitude is the mean value of the apparent range of those back scattering echoes. These results imply that HF sounder may be utilized to measure the surface roughness of planetary bodies in terms of the RMS gradient of the surface. Refrence: H. Oya and T. Ono, A new altimeter for Mars land shape observations utilizing the ionospheric sounder system onboard the Planet-B spacecraft, Earth Planets Space, Vol. 50, pp.229-234, 1998 T. Kobayashi, H. Oya, and T. Ono, A-scope analysis of subsurface radar sounding of lunar mare region, Earth Planets Space, Vol. 54, pp.973-982, 2002

  16. Data Assimilation of AIRS Water Vapor Profiles: Impact on Precipitation Forecasts for Atmospheric River Cases Affecting the Western of the United States

    Science.gov (United States)

    Blankenship, Clay; Zavodsky, Bradley; Jedlovec, Gary; Wick, Gary; Neiman, Paul

    2013-01-01

    Atmospheric rivers are transient, narrow regions in the atmosphere responsible for the transport of large amounts of water vapor. These phenomena can have a large impact on precipitation. In particular, they can be responsible for intense rain events on the western coast of North America during the winter season. This paper focuses on attempts to improve forecasts of heavy precipitation events in the Western US due to atmospheric rivers. Profiles of water vapor derived from from Atmospheric Infrared Sounder (AIRS) observations are combined with GFS forecasts by a three-dimensional variational data assimilation in the Gridpoint Statistical Interpolation (GSI). Weather Research and Forecasting (WRF) forecasts initialized from the combined field are compared to forecasts initialized from the GFS forecast only for 3 test cases in the winter of 2011. Results will be presented showing the impact of the AIRS profile data on water vapor and temperature fields, and on the resultant precipitation forecasts.

  17. Mid-Infrared Lasers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Mid Infrared DIAL systems can provide vital data needed by atmospheric scientists to understand atmospheric chemistry. The Decadal Survey recommended missions, such...

  18. Remote sensing of near-infrared chlorophyll fluorescence from space in scattering atmospheres: implications for its retrieval and interferences with atmospheric CO2 retrievals

    OpenAIRE

    J. McDuffie; L. Guanter; C. O'Dell; C. Frankenberg

    2012-01-01

    With the advent of dedicated greenhouse gas space-borne spectrometers sporting high resolution spectra in the O2 A-band spectral region (755–774 nm), the retrieval of chlorophyll fluorescence has become feasible on a global scale. If unaccounted for, however, fluorescence can indirectly perturb the greenhouse gas retrievals as it perturbs the oxygen absorption features. As atmospheric CO2 measurements are used to invert net fluxes at the land–atmosphere interface, a bias caused by fluore...

  19. VARIABILITY OF ATMOSPHERIC CO2 OVER INDIA AND SURROUNDING OCEANS AND CONTROL BY SURFACE FLUXES

    Directory of Open Access Journals (Sweden)

    R. K. Nayak

    2012-08-01

    Full Text Available In the present study, seasonal and inter-annual variability of atmospheric CO2 concentration over India and surrounding oceans during 2002–2010 derived from Atmospheric InfrarRed Sounder observation and their relation with the natural flux exchanges over terrestrial Indian and surrounding oceans were analyzed. The natural fluxes over the terrestrial Indian in the form of net primary productivity (NPP were simulated based on a terrestrial biosphere model governed by time varying climate parameters (solar radiation, air temperature, precipitation etc and satellite greenness index together with the land use land cover and soil attribute maps. The flux exchanges over the oceans around India (Tropical Indian Ocean: TIO were calculated based on a empirical model of CO2 gas dissolution in the oceanic water governed by time varying upper ocean parameters such as gradient of partial pressure of CO2 between ocean and atmosphere, winds, sea surface temperature and salinity. Comparison between the variability of atmospheric CO2 anomaly with the anomaly of surface fluxes over India and surrounding oceans suggests that biosphere uptake over India and oceanic uptake over the south Indian Ocean could play positive role on the control of seasonal variability of atmospheric carbon dioxide growth rate. On inter-annual scale, flux exchanges over the tropical north Indian Ocean could play positive role on the control of atmospheric carbon dioxide growth rate.

  20. Variability of Atmospheric CO2 Over India and Surrounding Oceans and Control by Surface Fluxes

    Science.gov (United States)

    Nayak, R. K.; Dadhwal, V. K.; Majumdar, A.; Patel, N. R.; Dutt, C. B. S.

    2011-08-01

    In the present study, seasonal and inter-annual variability of atmospheric CO2 concentration over India and surrounding oceans during 2002-2010 derived from Atmospheric InfrarRed Sounder observation and their relation with the natural flux exchanges over terrestrial Indian and surrounding oceans were analyzed. The natural fluxes over the terrestrial Indian in the form of net primary productivity (NPP) were simulated based on a terrestrial biosphere model governed by time varying climate parameters (solar radiation, air temperature, precipitation etc) and satellite greenness index together with the land use land cover and soil attribute maps. The flux exchanges over the oceans around India (Tropical Indian Ocean: TIO) were calculated based on a empirical model of CO2 gas dissolution in the oceanic water governed by time varying upper ocean parameters such as gradient of partial pressure of CO2 between ocean and atmosphere, winds, sea surface temperature and salinity. Comparison between the variability of atmospheric CO2 anomaly with the anomaly of surface fluxes over India and surrounding oceans suggests that biosphere uptake over India and oceanic uptake over the south Indian Ocean could play positive role on the control of seasonal variability of atmospheric carbon dioxide growth rate. On inter-annual scale, flux exchanges over the tropical north Indian Ocean could play positive role on the control of atmospheric carbon dioxide growth rate.

  1. A 2007-2015 record of global atmospheric dust seen from space

    Science.gov (United States)

    Clarisse, Lieven; Coheur, Pierre-François; Hadji-Lazaro, Juliette; Clerbaux, Cathy

    2016-04-01

    Satellite sounders are ideal for measuring the highly variable global atmospheric aerosol distributions, as they provide daily global coverage. Aeolian dust can particularly well be measured by infrared satellite instruments which can differentiate dust from other aerosol and can measure both during day and night, over land and over ocean. They also have an enhanced sensitivity to coarse mode particles. We start this talk with an overview of the state of the art of satellite measurements of aerosols before moving on to measurements of the advanced hyperspectral infrared sounder IASI. We present an IASI-derived dust product, first through examples, then through global distributions and monthly and seasonal climatologies. A preliminary validation of the measurements is presented, comparing them with collocated Aeronet observations. The measurements are then used to evaluate the state of the art ECMWF-MACC model. In the final part of the talk the 8 year IASI dataset is presented and analysed using timeseries over selected regions, with a focus on seasonal and multi-year trends.

  2. Hydrometeorological characteristics of rain-on-snow events associated with atmospheric rivers

    Science.gov (United States)

    Guan, Bin; Waliser, Duane E.; Ralph, F. Martin; Fetzer, Eric J.; Neiman, Paul J.

    2016-03-01

    Atmospheric rivers (ARs) are narrow, elongated, synoptic corridors of enhanced water vapor transport that play an important role in regional weather/hydrology. Rain-on-snow (ROS) events during ARs present enhanced flood risks due to the combined effects of rainfall and snowmelt. Focusing on California's Sierra Nevada, the study identifies ROS occurrences and their connection with ARs during the 1998-2014 winters. AR conditions, which occur during 17% of all precipitation events, are associated with 50% of ROS events (25 of 50). Composite analysis shows that compared to ARs without ROS, ARs with ROS are on average warmer by ~2 K, with snow water equivalent loss of ~0.7 cm/d (providing 20% of the combined water available for runoff) and ~50% larger streamflow/precipitation ratios. Atmospheric Infrared Sounder retrievals reveal distinct offshore characteristics of the two types of ARs. The results highlight the potential value of observing these events for snow, rain, and flood prediction.

  3. An efficient method for computing atmospheric radiances in clear-sky and cloudy conditions

    International Nuclear Information System (INIS)

    A computationally efficient method is developed to simulate the radiances in a scattering and absorbing atmosphere along an arbitrary path in the spectral region ranging from visible to far-infrared with a spectral resolution of 1 cm-1. For a given spectral region, the method is based on fitting radiances pre-calculated from the discrete ordinate radiative transfer (DISORT) at several wavenumbers. Radiances at other wavenumbers are interpolated based on the pre-computed total absorption and scattering optical thicknesses and the surface albedo. The computational efficiency and accuracy of the method are tested in comparison with rigorous simulations for various scenarios under the same conditions. For both clear-sky and cloud atmospheres, the present method is at least 140 times faster than the direct application of DISORT. Across the spectral range, the standard relative differences between the new method and the DISORT are less than 2% for clear-sky conditions. Root-mean-square (RMS) differences of the top of the atmosphere (TOA) brightness temperatures between the new method and DISORT, for atmospheric infrared sounder (AIRS) channels over clear-sky, ice cloudy and water cloudy skies, are within the noise equivalent differential temperature (NEDT) of the AIRS sensor. The fast method is also applied to simulations of the spectral downwelling radiance measured by the Fourier transform infrared (FTIR) interferometer, and to the simulations of the AIRS upwelling radiances under clear-sky and cloudy conditions.

  4. Observation of the exhaust plume from the space shuttle main engines using the microwave limb sounder

    Directory of Open Access Journals (Sweden)

    H. C. Pumphrey

    2011-01-01

    Full Text Available A space shuttle launch deposits 700 tonnes of water in the atmosphere. Some of this water is released into the upper mesosphere and lower thermosphere where it may be directly detected by a limb sounding satellite instrument. We report measurements of water vapour plumes from shuttle launches made by the Microwave Limb Sounder (MLS on the Aura satellite. Approximately 50%–65% of shuttle launches are detected by MLS. The signal appears at a similar level across the upper 10 km of the MLS limb scan, suggesting that the bulk of the observed water is above the top of the scan. Only a small fraction at best of smaller launches (Ariane 5, Proton are detected. We conclude that the sensitivity of MLS is only just great enough to detect a shuttle sized launch, but that a suitably designed instrument of the same general type could detect the exhausts from a large proportion of heavy-lift launches.

  5. Continuous Flow Atmospheric Pressure Laser Desorption/Ionization Using a 6–7-µm-Band Mid-Infrared Tunable Laser for Biomolecular Mass Spectrometry

    OpenAIRE

    Ryuji Hiraguchi; Hisanao Hazama; Kenichirou Senoo; Yukinori Yahata; Katsuyoshi Masuda; Kunio Awazu

    2014-01-01

    A continuous flow atmospheric pressure laser desorption/ionization technique using a porous stainless steel probe and a 6–7-µm-band mid-infrared tunable laser was developed. This ion source is capable of direct ionization from a continuous flow with a high temporal stability. The 6–7-µm wavelength region corresponds to the characteristic absorption bands of various molecular vibration modes, including O–H, C=O, CH3 and C–N bonds. Consequently, many organic compounds and solvents, including ...

  6. Changes in atmospheric composition discerned from long-term NDACC measurements: trends in direct greenhouse gases derived from infrared solar absorption spectra recorded at the Jungfraujoch station

    OpenAIRE

    Mahieu, Emmanuel; Duchatelet, Pierre; Zander, Rodolphe; Lejeune, Bernard; Bader, Whitney; Demoulin, Philippe; Roland, Ginette; Servais, christian; Rinsland, C. P.; M. J. Kurylo; Braathen, G. O.

    2011-01-01

    The University of Liège (ULg) is operating -under clear sky conditions- two state-of-the-art Fourier Transform Infrared (FTIR) spectrometers at the high-altitude research station of the Jungfraujoch (Swiss Alps, 46.5ºN, 3580m asl), within the framework of the Network for the Detection of Atmospheric Composition Changes (NDACC). Routine FTIR operation started in 1984. Since then, it has been continued without disruption, allowing collecting more than 45000 high-resolution broadband IR solar ab...

  7. A Module for Assimilating Hyperspectral Infrared Retrieved Profiles into the Gridpoint Statistical Interpolation System for Unique Forecasting Applications

    Science.gov (United States)

    Berndt, Emily; Zavodsky, Bradley; Srikishen, Jayanthi; Blankenship, Clay

    2015-01-01

    Hyperspectral infrared sounder radiance data are assimilated into operational modeling systems however the process is computationally expensive and only approximately 1% of available data are assimilated due to data thinning as well as the fact that radiances are restricted to cloud-free fields of view. In contrast, the number of hyperspectral infrared profiles assimilated is much higher since the retrieved profiles can be assimilated in some partly cloudy scenes due to profile coupling other data, such as microwave or neural networks, as first guesses to the retrieval process. As the operational data assimilation community attempts to assimilate cloud-affected radiances, it is possible that the use of retrieved profiles might offer an alternative methodology that is less complex and more computationally efficient to solve this problem. The NASA Short-term Prediction Research and Transition (SPoRT) Center has assimilated hyperspectral infrared retrieved profiles into Weather Research and Forecasting Model (WRF) simulations using the Gridpoint Statistical Interpolation (GSI) System. Early research at SPoRT demonstrated improved initial conditions when assimilating Atmospheric Infrared Sounder (AIRS) thermodynamic profiles into WRF (using WRF-Var and assigning more appropriate error weighting to the profiles) to improve regional analysis and heavy precipitation forecasts. Successful early work has led to more recent research utilizing WRF and GSI for applications including the assimilation of AIRS profiles to improve WRF forecasts of atmospheric rivers and assimilation of AIRS, Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI) profiles to improve model representation of tropopause folds and associated non-convective wind events. Although more hyperspectral infrared retrieved profiles can be assimilated into model forecasts, one disadvantage is the retrieved profiles have traditionally been assigned the

  8. The Havemann-Taylor Fast Radiative Transfer Code: Exact fast radiative transfer for scattering atmospheres using Principal Components (PCs)

    Science.gov (United States)

    Havemann, Stephan; Thelen, Jean-Claude; Taylor, Jonathan P.; Keil, Andreas

    2009-03-01

    The Havemann-Taylor Fast Radiative Transfer Code (HT-FRTC) has been developed for the simulation of highly spectrally resolved measurements from satellite based (i.e. Infrared Atmospheric Sounding Interferometer (IASI), Atmospheric Infrared Sounder (AIRS)) and airborne (i.e. Atmospheric Research Interferometer Evaluation System (ARIES)) instruments. The use of principle components enables the calculation of a complete spectrum in less than a second. The principal compoents are derived from a diverse training set of atmospheres and surfaces and contain their spectral characteristics in a highly compressed form. For any given atmosphere/surface, the HT-FRTC calculates the weightings (also called scores) of a few hundred principal components based on selected monochromatic radiative transfer calculations, which is far cheaper than thousands of channel radiance calculations. By intercomparison with line-by-line and other fast models the HT-FRTC has been shown to be accurate. The HT-FRTC has been successfully applied to simultaneous variational retrievals of atmospheric temperature and humidity profiles, surface temperature and surface emissivity over land. This is the subject of another presentation at this conference. The HT-FRTC has now also been extended to include an exact treatment of scattering by aerosols/clouds. The radiative transfer problem is solved using a discrete ordinate method (DISORT). Modelling results at high-spectral resolution for non-clear sky atmospheres obtained with the HT-FRTC are presented.

  9. Next Generation Grating Spectrometer Sounders for LEO and GEO

    Science.gov (United States)

    Pagano, Thomas S.

    2011-01-01

    AIRS and MODIS are widely used for weather, climate, composition, carbon cycle, cross-calibration, and applications. The community asking for new capability in the 2020 timeframe, capabilities desired: (1) Hyperspectral UV to LWIR, High Spatial ?1km IFOV (2) Maximize Synergies of Solar Reflected and IR. Synergies with OCO-2. We expect more users and applications of next gen LEO IR Sounder than GEO. These include: weather, climate, GHG monitoring, aviation, disaster response. There is a new direction for imagers and sounders: (1) Separate Vis/NIR/SWIR from MWIR/LWIR instruments reduces technology risk and complexity. (2) Expect Costs to be lower than CrIS & VIIRS Some additional ideas to reduce costs include: (1) minimum set of requirements (2) mini-grating spectrometers. supports constellation for higher revisit (3) new technology to reduce instrument size (large format fpa's) (4) hosted payloads

  10. SAR/InSAR observation by an HF sounder

    Science.gov (United States)

    Kobayashi, T.; Ono, T.

    2007-03-01

    Application of SAR imaging algorithm to spaceborne HF sounder observation was studied. Two types of image ambiguity problems were addressed in the application. One is surface/subsurface image ambiguity arising from deep penetration of HF wave, and another is mirror image ambiguity that is inherent to dipole antenna SAR. A numerical model demonstrated that the surface/subsurface ambiguity can be mitigated by taking a synthetic aperture large enough to defocus subsurface objects. In order to resolve the mirror image ambiguity problem, an image superposition technique was proposed. The performance of the technique was demonstrated by using simulation data of the HF sounder observation to confirm the feasibility of HF SAR and HF InSAR observation.

  11. Near-infrared spectro-interferometry of Mira variables and comparisons to 1D dynamic model atmospheres and 3D convection simulations

    CERN Document Server

    Wittkowski, M; Freytag, B; Scholz, M; Hoefner, S; Karovicova, I; Whitelock, P A

    2016-01-01

    We obtained a total of 20 near-infrared K-band spectro-interferometric snapshot observations of the Mira variables o Cet, R Leo, R Aqr, X Hya, W Vel, and R Cnc with a spectral resolution of about 1500. We compared observed flux and visibility spectra with predictions by CODEX 1D dynamic model atmospheres and with azimuthally averaged intensities based on CO5BOLD 3D dynamic model atmospheres including convection. Our visibility data confirm the presence of spatially extended molecular atmospheres located above the continuum radii with large-scale inhomogeneities or clumps that contribute a few percent of the total flux. The detailed structure of the inhomogeneities or clumps show a variability on time scales of 3 months and above. Both modeling attempts provided satisfactory fits to our data. In particular, they are both consistent with the observed decrease in the visibility function at molecular bands of water vapor and CO, indicating a spatially extended molecular atmosphere. Observational variability phase...

  12. Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant stars. IV. Oxygen diagnostics in extremely metal-poor red giants with infrared OH lines

    CERN Document Server

    Dobrovolskas, V; Bonifacio, P; Caffau, E; Ludwig, H -G; Steffen, M; Spite, M

    2015-01-01

    Context. Although oxygen is an important tracer of Galactic chemical evolution, measurements of its abundance in the atmospheres of the oldest Galactic stars are still scarce and rather imprecise. At the lowest end of the metallicity scale, oxygen can only be measured in giant stars and in most of cases such measurements rely on a single forbidden [O I] 630 nm line that is very weak and frequently blended with telluric lines. Although molecular OH lines located in the ultraviolet and infrared could also be used for the diagnostics, oxygen abundances obtained from the OH lines and the [O I] 630 nm line are usually discrepant to a level of ~0.3-0.4 dex. Aims. We study the influence of convection on the formation of the infrared (IR) OH lines and the forbidden [O I] 630 nm line in the atmospheres of extremely metal-poor (EMP) red giant stars. Methods. We used high-resolution and high signal-to-noise ratio spectra of four EMP red giant stars obtained with the VLT CRIRES spectrograph. For each EMP star, 4-14 IR OH...

  13. Effect of atmospheric refraction on radiative transfer in visible and near-infrared band: Model development, validation, and applications

    Science.gov (United States)

    Hu, Shuai; Gao, Tai-chang; Li, Hao; Liu, Lei; Liu, Xi-chuan; Zhang, Ting; Cheng, Tian-ji; Li, Wan-tong; Dai, Zhong-hua; Su, Xiaojian

    2016-03-01

    Refraction is an important factor influencing radiative transfer since it can modify the propagation trajectory and polarization states of lights; therefore, it is necessary to quantitively evaluate the effect of atmospheric refraction on radiative transfer process. To this end, a new atmospheric radiative transfer model including refraction process is proposed. The model accuracy is validated against benchmark results, literature results, and well-tested radiative transfer models such as discrete coordinate method and RT3/PolRadtran. The impact of atmospheric refraction on both polarized radiance and fluxes is discussed for pure Rayleigh scattering atmosphere, atmosphere with aerosol, and cloud. The results show that atmospheric refraction has a significant influence on both the radiance and polarization states of diffuse light, where the relative change of the radiance of reflected light and transmitted light due to refraction can achieve 6.3% and 7.4% for Rayleigh scattering atmosphere, 7.2% and 7.8% for atmosphere with aerosol, and 6.2% and 6.8% for cloudy atmosphere, respectively. The relative change of the degree of polarization ranges from near zero in the horizon to 9.5% near neutral points. The angular distribution pattern of the relative change of the radiance for atmosphere with aerosol and cloud is very similar to that for pure Rayleigh scattering case, where its magnitude decreases gradually with the increasing of zenith angle for reflected light; but for transmitted light, the variation characteristics is opposite. The impact of refraction is gradually enhanced with the increasing of solar zenith angles and the optical depth of aerosol and cloud. As the wavelength of incident light increases, the impact declines rapidly for Rayleigh scattering medium. The relative change of the fluxes due to refraction is most notable for Middle Latitude Winter profile (about 8.2043% and 7.3225% for the transmitted and reflected light, respectively, at 0.35 µm). With

  14. Analysis on Infrared Spectrometer System Specification for Atmospheric Composition Detecting%大气成分探测红外光谱仪系统指标分析

    Institute of Scientific and Technical Information of China (English)

    齐卫红; 尉昊赟; 阴丽娜

    2013-01-01

    由温室气体引起的全球气候变化和环境污染已经受到全世界的广泛关注。进行大气成分探测,对于更好地了解温室效应产生的细节、大气分子的光化学性质对臭氧层的影响以及大气污染机制都具有重要意义。由于大气成分种类较多,其红外吸收光谱密集且复杂,因此大气成分探测仪器需要有较高的光谱分辨能力和信噪比。文章进行了大气成分探测的总体指标需求分析,并据此确定了大气成分探测红外光谱仪的主要技术指标。为了满足指标要求,该光谱仪采用傅里叶变换红外光谱仪的总体方案。通过仪器性能影响因素分析和系统优化,使得该仪器的最终设计结果满足指标要求。%Global climate change and environmental pollution caused by greenhouse gases has received ex-tensive attention all over the world. Detecting atmospheric composition is especial important for a better under-standing of the detail of the green house effect, the influences on the ozonosphere of atmospheric photochemistry, as well as the mechanism of the air pollution. Because the kinds of atmospheric composition and their infrared absorption spectral lines are very dense and complex, atmospheric composition instruments need to have high spectral resolution and high signal-to-noise ratio (SNR). This report briefly introduced the specification require-ment analysis for space atmospheric detecting, and the main specifications of the instrument for space atmospher-ic detecting are defined. For realizing the main specifications, the overall scheme of the instrument adopts Fourier Transform Infrared Spectrometer (FTIRS). The final design of the instrument meets the specifications through influence factor analysis and system optimization. Finally, the measurement result was given.

  15. Validation of Atmospheric Correction of Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) Radiance Data Based on Radiative Transfer Modeling

    Science.gov (United States)

    Carrare, V.; Conel, J. E.

    1993-01-01

    An evaluation of atmospheric correction of AVIRIS data using radiative transfer codes LOWTRAN7 and MODTRAN is presented. The algorithm employed is based on a simple model of radiance L at each wavelength at the sensor that can be written approximately LAV=Lp+Tp, where subscript AV referes to AVIRIS, Lp is the path radiance and Tp is the diffuse + direct transmitted radiance of the atmosphere at AVIRIS.

  16. Sounder updates for statistical model predictions of maximum usable frequencies on HF sky wave paths

    Science.gov (United States)

    Reilly, Michael H.; Daehler, Mark

    1986-12-01

    A method is presented for the short-term prediction of maximum usable frequencies (MUFs) in a large communications region. It is shown how ionospheric measurements from a network of ionospheric sounders can be used to update sunspot number or solar 10.7 cm flux inputs to a climatological MUF prediction model. MINIMUF in this case, which is then used to predict MUFs on paths throughout the region. Analysis of mid-latitude oblique-incidence sounder data sets indicates the advantage gained from single-path sounder updates of flux for MUF predictions on adjacent paths. Under specified conditions a further dramatic improvement in MUF prediction accuracy is found from spatial interpolation of sounder-updated flux values. MUF prediction accuracies within 0.5 MHz are obtained for fairly modest sounder network deployments, in which the sounder midpath point distributions and updating frequency satisfy particular requirements.

  17. Acoustic-sounder investigation of the effects of boundary-layer decoupling on long-distance polutant transport

    International Nuclear Information System (INIS)

    The formation of the nocturnal surface temperature inversion results in a decrease in vertical momentum transfer which, in turn, is accompanied by an associated reduction in the transfer of pollutants from the atmosphere to surface sinks, thus decoupling the surface layer from the layer above the inversion. The diurnal oscillation in the surface temperature profiles may therefore have a significant effect upon the transport of atmospheric pollutants over long distances. Flights of a large manned balloon with a diverse array of chemical and meteorological instrumentation aboard, known as Project de Vinci, provided a unique opportunity to combine acoustic-sounder observations of qualitative temperature structure in the atmospheric boundary layer with the chemical measurements necessary to gain increased understanding of this decoupling process and its consequences for pollutant transport. The data collected on ozone on the balloon and the grounds are reported

  18. Potential for the use of reconstructed IASI radiances in the detection of atmospheric trace gases

    Directory of Open Access Journals (Sweden)

    N. C. Atkinson

    2010-02-01

    Full Text Available Principal component (PC analysis has received considerable attention as a technique for the extraction of meteorological signals from hyperspectral infra-red sounders such as the Infrared Atmospheric Sounding Interferometer (IASI and the Atmospheric Infrared Sounder (AIRS. In addition to achieving substantial bit-volume reductions for dissemination purposes, the technique can also be used to generate reconstructed radiances in which random instrument noise has been suppressed. To date, most studies have been in the context of Numerical Weather Prediction (NWP. This study examines the potential of PC analysis for chemistry applications.

    A major concern in the use of PC analysis for chemistry has been that the spectral features associated with trace gases may not be well represented in the reconstructed spectra, either due to deficiencies in the training set or due to the limited number of PC scores used in the radiance reconstruction. In this paper we show examples of reconstructed IASI radiances for several trace gases: ammonia, sulphur dioxide, methane and carbon monoxide. It is shown that care must be taken in the selection of spectra for the initial training set: an iterative technique, in which outlier spectra are added to a base training set, gives the best results. For the four trace gases examined, the chemical signatures are retained in the reconstructed radiances, whilst achieving a substantial reduction in instrument noise.

    A new regional re-transmission service for IASI is scheduled to start in 2010, as part of the EUMETSAT Advanced Retransmission Service (EARS. For this EARS-IASI service it is intended to include PC scores as part of the data stream. The paper describes the generation of the reference eigenvectors for this new service.

  19. Spatial heterogeneity in geothermally-influenced lakes derived from atmospherically corrected Landsat thermal imagery and three-dimensional hydrodynamic modelling

    Science.gov (United States)

    Allan, Mathew G.; Hamilton, David P.; Trolle, Dennis; Muraoka, Kohji; McBride, Christopher

    2016-08-01

    Atmospheric correction of Landsat 7 thermal data was carried out for the purpose of retrieval of lake skin water temperature in Rotorua lakes, and Lake Taupo, North Island, New Zealand. The effect of the atmosphere was modelled using four sources of atmospheric profile data as input to the MODerate resolution atmospheric TRANsmission (MODTRAN) radiative transfer model. The retrieved skin water temperatures were validated using a high-frequency temperature sensor deployed from a monitoring buoy at the water surface of Lake Rotorua. The most accurate atmospheric correction method was with Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric profile data (root-mean-square-error, RMSE, 0.48 K), followed by radiosonde (0.52 K), Atmospheric Infrared Sounder (AIRS) Level 3 (0.54 K), and the NASA atmospheric correction parameter calculator (0.94 K). Retrieved water temperature was used for assessing spatial heterogeneity and accuracy of surface water temperature simulated with a three-dimensional (3-D) hydrodynamic model of Lake Rotoehu, located approximately 20 km east of Lake Rotorua. This comparison indicated that the model was suitable for reproducing the dominant horizontal variations in surface water temperature in the lake. This study demonstrated the potential of accurate satellite-based thermal monitoring to validate temperature outputs from 3-D hydrodynamic model simulations. It also provided atmospheric correction options for local and global applications of Landsat thermal data.

  20. Analysis and interpretation of satellite measurements in the near-infrared spectral region: Atmospheric carbon dioxide and methane

    OpenAIRE

    Schneising, Oliver

    2008-01-01

    Carbon dioxide (CO2) and methane (CH4) are the two most important anthropogenic greenhouse gases. SCIAMACHY on ENVISAT is the first satellite instrument whose measurements are sensitive to concentration changes of the two gases at all altitude levels down to the Earth's surface where the source/sink signals are largest. Three years (2003-2005) of SCIAMACHY near-infrared nadir measurements have been processed to simultaneously retrieve vertical columns of CO2, CH4, and oxygen using the scienti...

  1. Current Status of Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES)

    Science.gov (United States)

    Shiotani, M.; Takayanagi, M.

    2009-12-01

    Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) was designed to be aboard the Japanese Experiment Module (JEM) on the International Space Station (ISS) as a collaboration project of Japan Aerospace Exploration Agency (JAXA) and National Institute of Information and Communications Technology (NICT). Mission Objectives are: i) Space demonstration of superconductive mixer and 4-K mechanical cooler for the submillimeter limb-emission sounding, and ii) global observations of atmospheric minor constituents in the stratosphere (O3, HCI, CIO, HO2, HOCI, BrO, O3 isotopes, HNO3, CH3CN, etc), contributing to the atmospheric sciences. The SMILES observation is characterized as aiming at variation and its impact of radical species in the stratosphere. Based on its high sensitivity in detecting atmospheric limb emission of the submillimeter wave range, JEM/SMILES will make measurements on several radical species crucial to the ozone chemistry. It will be launched with H-II Transfer Vehicle (HTV) by the latest version of H-II rocket (H-IIB) on September 10th from Tanegashima Space Center in Japan. In this presentaiton, the up-to-date information of SMILES operation as well as the preliminary result of observation data processing.

  2. Current status of Superconductive Submillimeter-Wave Limb-Emission Sounder (SMILES)

    Science.gov (United States)

    Shiotani, Masato

    Superconductive Submillimeter-Wave Limb-Emission Sounder (SMILES) was designed to be aboard the Japanese Experiment Module (JEM) on the International Space Station (ISS) as a collaboration project of Japan Aerospace Exploration Agency (JAXA) and National Institute of Information and Communications Technology (NICT). Mission Objectives are: i) Space demonstration of superconductive mixer and 4-K mechanical cooler for the submillimeter limbemission sounding, and ii) global observations of atmospheric minor constituents in the stratosphere (O3, HCI, CIO, HO2, HOCI, BrO, O3 isotopes, HNO3, CH3CN, etc), contributing to the atmospheric sciences. The SMILES observation is characterized as aiming at variation and its impact of radical species in the stratosphere. Based on its high sensitivity in detecting atmospheric limb emission of the submillimeter wave range, JEM/SMILES will make measurements on several radical species crucial to the ozone chemistry (normal O3, isotope O3, ClO, HCl, HOCl, BrO, HO2, and H2O2). The SMILES will also try to observe isotopic composition of ozone. Fabrication of the proto-flight model (PFM) and functional test have been done, and it is aiming at the launch scheduled in 2009 by the H-II Transfer Vehicle (HTV).

  3. Microwave Limb Sounder/El Nino Watch - Water Vapor Measurement, October, 1997

    Science.gov (United States)

    1997-01-01

    This image shows atmospheric water vapor in Earth's upper troposphere, about 10 kilometers (6 miles) above the surface, as measured by the Microwave Limb Sounder (MLS) instrument flying aboard the Upper Atmosphere Research Satellite. These data collected in early October 1997 indicate the presence of El Nino by showing a shift of humidity from west to east (blue and red areas) along the equatorial Pacific Ocean. El Nino is the term used when the warmest equatorial Pacific Ocean water is displaced toward the east. The areas of high atmospheric moisture correspond to areas of very warm ocean water. Warmer water evaporates at a higher rate and the resulting warm moist air then rises, forming tall cloud towers. In the tropics, the warm water and the resulting tall cloud towers typically produce large amounts of rain. The MLS instrument, developed at NASA's Jet Propulsion Laboratory, measures humidity at the top of these clouds, which are very moist. This rain is now occurring in the eastern Pacific Ocean and has left Indonesia (deep blue region) unusually dry, resulting in the current drought in that region. This image also shows moisture moving north into Mexico, an effect of several hurricanes spawned by the warm waters of El Nino.

  4. Remote sensing of the earth's atmosphere by means of infrared spectroscopy: Retrieval theory and application; Zur Fernerkundung der Erdatmosphaere mittels Infrarotspektrometrie: Rekonstruktionstheorie und Anwendung

    Energy Technology Data Exchange (ETDEWEB)

    Clarmann, T. von

    2003-11-01

    Remote sensing retrieval theory covers the methodology used to infer information on unknown parameters of the object under investigation from indirect remote measurements. Application of infrared spectrometry of the atmosphere leads to the inverse solution of the atmospheric radiative transfer equation. Its successful inversion depends on (1) a suitable forward model for simulation of atmospheric radiative transfer, (2) the appropriate definition of the retrieval parameter vector, (3) an optimized vector containing the measurements, (4) the appropriate formulation of a constraint, and (5) a tool for stable numeric inversion. Experiments with limb emission spectrometers as well as uplooking emission and absorption spectrometers serve as examples for discussion of application of relevant retrieval schemes. With respect to retrieval theory, the following progress is reported and the following findings were gained: - An optimized radiative transfer model for application within a retrieval program was developed. This model is both accurate and efficient. It includes all radiative processes relevant to application to atmospheric infrared spectrometry, including refraction, absorption, emission, scattering, line-coupling and non-local thermodynamic equilibrium. - Objective selection of spectral gridpoints used for data analysis reduces the retrieval error and reduces computer resources needed. The more spectral data are considered, the more information is used for the retrieval of the target parameter. This is counterbalanced by the fact that radiance at the considered gridpoints depend on further parameters which may be uncertain and thus contribute to the error budget. Tentative retrieval of all these parameters from the measurement leads to an impracticable large number of unknowns. Therefore, an objective method for an optimized selection of spectral data was developed. - It is shown that for limb measurements of medium spectral resolution the unconstrained solution

  5. Simulation of source intensity variations from atmospheric dust for solar occultation Fourier transform infrared spectroscopy at Mars

    Science.gov (United States)

    Olsen, K. S.; Toon, G. C.; Strong, K.

    2016-05-01

    A Fourier transform spectrometer observing in solar occultation mode from orbit is ideally suited to detecting and characterizing vertical profiles of trace gases in the Martian atmosphere. This technique benefits from a long optical path length and high signal strength, and can have high spectral resolution. The Martian atmosphere is often subject to large quantities of suspended dust, which attenuates solar radiation along the line-of-sight. An instrument making solar occultation measurements scans the limb of the atmosphere continuously, and the optical path moves through layers of increasing or decreasing dust levels during a single interferogram acquisition, resulting in time-varying signal intensity. If uncorrected, source intensity variations (SIVs) can affect the relative depth of absorption lines, negatively impacting trace gas retrievals. We have simulated SIVs using synthetic spectra for the Martian atmosphere, and investigated different techniques to mitigate the effects of SIVs. We examined high-pass filters in the wavenumber domain, and smoothing methods in the optical path difference (OPD) domain, and conclude that using a convolution operator in the OPD domain can isolate the SIVs and be used to correct for it. We observe spectral residuals of less than 0.25% in both high- and low-dust conditions, and retrieved volume mixing ratio vertical profile differences on the order of 0.5-3% for several trace gases known to be present in the Martian atmosphere. These differences are smaller than those caused by adding realistic noise to the spectra. This work thus demonstrates that it should be possible to retrieve vertical profiles of trace gases in a dusty Martian atmosphere using solar occultation if the interferograms are corrected for the effects of dust.

  6. Study of the atmospheric flashes and man-made global phenomena ultraviolet and infrared glow of the night air on the board of satellite "VERNOV"

    Science.gov (United States)

    Garipov, Gali; Panasyuk, Mikhael; Svertilov, Sergey; Bogomolov, Vitaliy; Barinova, Vera; Saleev, Kirill

    2016-04-01

    The set of scientific payload for optical observation on-board of "Vernov" satellite, launched at July 8, 2014, had measured transient (millisecond) flashes in the atmosphere in two wavelength bands: ultraviolet (UV,240-380nm) and red-infrared (IR,610-800nm). Global distribution of the flashes, their frequency and time parameters are studied in this work. Transient flashes measured from the satellite frequently were detected in high latitudes in winter time. Flashes in equatorial region were observed in series which were stretched along magnetic meridian and some of them were detected in cloudless regions. At night time when the Earth atmosphere was observed in nadir direction there were registered the optical signals of artificial origin, distributed along the meridian in an extended region of latitude in the Northern and Southern hemispheres of the Earth, modulated by low frequency and at the coincidence of the orbits with the geographic location of the powerful radio stations. Examples of the waveforms of such signals in UV and IR spectral ranges and their global distribution are presented in this presentation. Particular attention is paid to man-made causes of the glow in the ionosphere under the influence of the high power radio wave transmitters of low (LF) and high frequencies (HF). The height of the luminescence source and components of the atmosphere, which can be the sources of this radiation, are discussed.

  7. The SARTre model for radiative transfer in spherical atmospheres and its application to the derivation of cirrus cloud properties

    Energy Technology Data Exchange (ETDEWEB)

    Mendrock, J.

    2006-07-01

    Modeling of radiative transfer (RT) is one of the essentials of atmospheric remote sensing. It has been common to use separate models for the simulation of shortwave radiation dominated by scattering of sunlight and longwave radiation characterized by emission from trace gases. These days also shortwave instruments are operated in limb mode, which demand models taking the sphericity of the Earth and atmosphere into account. On the other hand, infrared and microwave sounders are increasingly being used for the observation of ice clouds, that necessitate the modeling of scattering by cloud particles. Both trends require RT models, that are capable of taking into account scattering as well as the sphericity of the atmosphere. This suggests a unified handling of short- and longwave radiation, which furthermore allows for a consistent evaluation of multispectral data. Focusing on these aspects, the RT-model SARTre ([Approximate] Spherical Atmospheric Radiative Transfer model) has been developed. To our knowledge, SARTre is the first model, that is capable of limb modeling in the ultraviolet, visible, near to far infrared, and microwave spectral region. Here, algorithm baseline, implementation, verification and validation of SARTre are presented. SARTre has been used to study effects of cirrus clouds on infrared limb emission spectra. An exemplary retrieval of cirrus parameters from MIPAS measurements is demonstrated, and the plausibility of the results is discussed. (orig.)

  8. Impact of the Assimilation of Hyperspectral Infrared Profiles on Advanced Weather and Research Model Simulations of a Non-Convective Wind Event

    Science.gov (United States)

    Berndt, Emily B.; Zavodsky, Bradley T; Jedlovec, Gary J.; Elmer, Nicholas J.

    2013-01-01

    Non-convective wind events commonly occur with passing extratropical cyclones and have significant societal and economic impacts. Since non-convective winds often occur in the absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less likely to heed high wind warnings and continue daily activities. Thus non-convective wind events result in as many fatalities as straight line thunderstorm winds. One physical explanation for non-convective winds includes tropopause folds. Improved model representation of stratospheric air and associated non-convective wind events could improve non-convective wind forecasts and associated warnings. In recent years, satellite data assimilation has improved skill in forecasting extratropical cyclones; however errors still remain in forecasting the position and strength of extratropical cyclones as well as the tropopause folding process. The goal of this study is to determine the impact of assimilating satellite temperature and moisture retrieved profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS), Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an associated high wind event that impacted the Northeast United States on 09 February 2013. Model simulations using the Advanced Research Weather Research and Forecasting Model (ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational North American Model (NAM). The results from the satellite assimilation run are compared to a control experiment (without hyperspectral IR retrievals), North American Regional Reanalysis (NARR) reanalysis, and Rapid Refresh analyses.

  9. Impact of the Assimilation of Hyperspectral Infrared Retrieved Profiles on Advanced Weather and Research Model Simulations of a Non-Convective Wind Event

    Science.gov (United States)

    Berndt, E. B.; Zavodsky, B. T.; Folmer, M. J.; Jedlovec, G. J.

    2014-01-01

    Non-convective wind events commonly occur with passing extratropical cyclones and have significant societal and economic impacts. Since non-convective winds often occur in the absence of specific phenomena such as a thunderstorm, tornado, or hurricane, the public are less likely to heed high wind warnings and continue daily activities. Thus non-convective wind events result in as many fatalities as straight line thunderstorm winds. One physical explanation for non-convective winds includes tropopause folds. Improved model representation of stratospheric air and associated non-convective wind events could improve non-convective wind forecasts and associated warnings. In recent years, satellite data assimilation has improved skill in forecasting extratropical cyclones; however errors still remain in forecasting the position and strength of extratropical cyclones as well as the tropopause folding process. The goal of this study is to determine the impact of assimilating satellite temperature and moisture retrieved profiles from hyperspectral infrared (IR) sounders (i.e. Atmospheric Infrared Sounder (AIRS), Cross-track Infrared and Microwave Sounding Suite (CrIMSS), and Infrared Atmospheric Sounding Interferometer (IASI)) on the model representation of the tropopause fold and an associated high wind event that impacted the Northeast United States on 09 February 2013. Model simulations using the Advanced Research Weather Research and Forecasting Model (ARW) were conducted on a 12-km grid with cycled data assimilation mimicking the operational North American Model (NAM). The results from the satellite assimilation run are compared to a control experiment (without hyperspectral IR retrievals), 32-km North American Regional Reanalysis (NARR) interpolated to a 12-km grid, and 13-km Rapid Refresh analyses.

  10. Retrieval of Atmospheric CO2 and CH4 Variations Using Ground-Based High Resolution Fourier Transform Infrared Spectra

    Directory of Open Access Journals (Sweden)

    Tian Yuan

    2015-01-01

    Full Text Available High resolution Fourier transform near IR solar spectra are used to estimate the column-averaged dry-air mole fraction (DMF of CO2 and CH4 variations in the atmosphere. The preliminary retrieval results for CO2 and CH4 variations in the area of Hefei, China, are presented, and the underlying error sources are also analyzed. Both a forward analysis and an inversion algorithm are included in the retrieval. The forward analysis uses the modeled atmospheric transmittance to line-by-line (LBL convolute the instrument line shape function. The influences of the temperature, pressure, humidity, and a priori gases are considered in the atmospheric transmittance model. The inversion algorithm is based on the nonlinear iterative and nonlinear least squares spectral fitting, which is used to obtain VCDCO2 and VCDCH4 (which represent vertical column density of CO2 and CH4, resp.. Furthermore, the VCDO2 is also retrieved for converting the VCDs into DMFs. DMFs are final products of data analysis. The inversion results can clearly resolve the tiny variations of CO2 and CH4 under strong atmospheric background. Spectral fitting residuals for both VCDCO2 and VCDCH4 are less than 0.5%. Finally, CO2 and CH4 diurnal variations are investigated based on a typical observation. About 2 ppm amplitude for DMFCO2 diurnal variations and less than 15 ppb amplitude for DMFCH4 are observed.

  11. Simultaneous atmospheric measurements using two Fourier transform infrared spectrometers at the Polar Environment Atmospheric Research Laboratory during spring 2006, and comparisons with the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer

    OpenAIRE

    D. Fu; K. A. Walker; R. L. Mittermeier; Strong, K.; Sung, K.; H. Fast; Bernath, P. F.; C. D. Boone; W. H. Daffer; Fogal, P.; Kolonjari, F.; P. Loewen; Manney, G. L.; O. Mikhailov

    2008-01-01

    The 2006 Canadian Arctic ACE (Atmospheric Chemistry Experiment) Validation Campaign collected measurements at the Polar Environment Atmospheric Research Laboratory (PEARL, 80.05° N, 86.42° W, 610 m above sea level) at Eureka, Canada from 17 February to 31 March 2006. Two of the ten instruments involved in the campaign, both Fourier transform spectrometers (FTSs), were operated simultaneously, recording atmospheric solar absorption spectra. The first instrument was an ABB Bomem...

  12. Characteristics of TIDs Observed in the Bottomside Ionospheric F-region Using the TIDDBIT HF Doppler Sounder

    Science.gov (United States)

    Crowley, G.

    2012-12-01

    HF Doppler sounders represent a low-cost and low-maintenance solution for monitoring wave activity in the F region ionosphere. HF Doppler sounders together with modern data analysis techniques can provide comprehensive traveling ionospheric disturbance (TID) characteristics, including both horizontal and vertical TID velocities and wavelengths across the entire spectrum from periods of 1 min to over an hour. Atmospheric and Space Technology Research Associates LLC has developed a new system called TIDDBIT (TID Detector Built in Texas), and data will be presented from a TIDDBIT system deployed in Virginia. Details of the analysis are provided by Crowley and Rodrigues [2012]. These results reinforce the relationship between atmospheric gravity waves (AGWs) and TIDs. The TID propagation azimuths rotate through 360 deg in 24 h, mimicking the rotation of the thermospheric winds but with approximately a 90 deg offset. The rotation of TID azimuths and thermospheric winds in Virginia is similar to that observed previously by other Northern Hemisphere systems [Crowley and McCrea, 1988] and opposite from the direction observed in Antarctica [Crowley et al., 1987]. These results illustrate the filtering effects that thermospheric neutral winds can have on the propagation of AGW. The completeness of the wave information obtained from the TIDDBIT system makes it possible to reconstruct the vertical displacement of isoionic contours over the 200 km horizontal dimension of the sounder array, and movies revealing the detailed shape and motion of isoionic surfaces will be shown. They resemble the surface of the ocean. Such information will be relevant for understanding the seeding of irregularities, as well as for several operational needs involving navigation, communication, and surveillance systems. Crowley, G. and I. W. McCrea (1988), A synoptic study of TIDs observed in the UK during the first WAGS campaign, October 10-18, 1985, Radio Sci., 23, 905-917. Crowley G., and F

  13. Validation of the Aura Microwave Limb Sounder HNO3 Measurements

    OpenAIRE

    Santee, M. L.; JPL, California Institute of Technology, Pasadena, USA; Lambert, A.; JPL, California Institute of Technology, Pasadena, USA; Read, W. G.; JPL, California Institute of Technology, Pasadena, USA; Livesey, N. J.; JPL, California Institute of Technology, Pasadena, USA; Cofield, R. E.; JPL, California Institute of Technology, Pasadena, USA; Cuddy, D. T.; JPL, California Institute of Technology, Pasadena, USA; Daffer, W. H.; JPL, California Institute of Technology, Pasadena, USA; Drouin, B. J.; JPL, California Institute of Technology, Pasadena, USA; Froidevaux, L.; JPL; Fuller, R. A.; JPL, California Institute of Technology, Pasadena, USA; Jarnot, R. F.; JPL, California Institute of Technology, Pasadena, USA; Knosp, B. W.; JPL, California Institute of Technology, Pasadena, USA; Manney, G. L.; JPL, California Institute of Technology, Pasadena, USA; Perun, V. S.; JPL, California Institute of Technology, Pasadena, USA; Snyder, W. V.; JPL, California Institute of Technology, Pasadena, USA

    2007-01-01

    We assess the quality of the version 2.2 (v2.2) HNO3 measurements from the Microwave Limb Sounder (MLS) on the Earth Observing System Aura satellite. The MLS HNO3 product has been greatly improved over that in the previous version (v1.5), with smoother profiles, much more realistic behavior at the lowest retrieval levels, and correction of a high bias caused by an error in one of the spectroscopy files used in v1.5 processing. The v2.2 HNO3 data are scientifically useful over t...

  14. Evaluation of Precipitation Detection over Various Surfaces from Passive Microwave Imagers and Sounders

    Science.gov (United States)

    Munchak, S. Joseph; Skofronick-Jackson, Gail

    2012-01-01

    During the middle part of this decade a wide variety of passive microwave imagers and sounders will be unified in the Global Precipitation Measurement (GPM) mission to provide a common basis for frequent (3 hr), global precipitation monitoring. The ability of these sensors to detect precipitation by discerning it from non-precipitating background depends upon the channels available and characteristics of the surface and atmosphere. This study quantifies the minimum detectable precipitation rate and fraction of precipitation detected for four representative instruments (TMI, GMI, AMSU-A, and AMSU-B) that will be part of the GPM constellation. Observations for these instruments were constructed from equivalent channels on the SSMIS instrument on DMSP satellites F16 and F17 and matched to precipitation data from NOAA's National Mosaic and QPE (NMQ) during 2009 over the continuous United States. A variational optimal estimation retrieval of non-precipitation surface and atmosphere parameters was used to determine the consistency between the observed brightness temperatures and these parameters, with high cost function values shown to be related to precipitation. The minimum detectable precipitation rate, defined as the lowest rate for which probability of detection exceeds 50%, and the detected fraction of precipitation, are reported for each sensor, surface type (ocean, coast, bare land, snow cover) and precipitation type (rain, mix, snow). The best sensors over ocean and bare land were GMI (0.22 mm/hr minimum threshold and 90% of precipitation detected) and AMSU (0.26 mm/hr minimum threshold and 81% of precipitation detected), respectively. Over coasts (0.74 mm/hr threshold and 12% detected) and snow-covered surfaces (0.44 mm/hr threshold and 23% detected), AMSU again performed best but with much lower detection skill, whereas TMI had no skill over these surfaces. The sounders (particularly over water) benefited from the use of re-analysis data (vs. climatology) to

  15. Near-infrared brightness of the Galilean satellites eclipsed in Jovian shadow: A new technique to investigate Jovian upper atmosphere

    International Nuclear Information System (INIS)

    Based on observations from the Hubble Space Telescope and the Subaru Telescope, we have discovered that Europa, Ganymede, and Callisto are bright around 1.5 μm even when not directly lit by sunlight. The observations were conducted with non-sidereal tracking on Jupiter outside of the field of view to reduce the stray light subtraction uncertainty due to the close proximity of Jupiter. Their eclipsed luminosity was 10–6-10–7 of their uneclipsed brightness, which is low enough that this phenomenon has been undiscovered until now. In addition, Europa in eclipse was <1/10 of the others at 1.5 μm, a potential clue to the origin of the source of luminosity. Likewise, Ganymede observations were attempted at 3.6 μm by the Spitzer Space Telescope, but it was not detected, suggesting a significant wavelength dependence. It is still unknown why they are luminous even when in the Jovian shadow, but forward-scattered sunlight by hazes in the Jovian upper atmosphere is proposed as the most plausible candidate. If this is the case, observations of these Galilean satellites while eclipsed by the Jovian shadow provide us with a new technique to investigate the Jovian atmospheric composition. Investigating the transmission spectrum of Jupiter by this method is important for investigating the atmosphere of extrasolar giant planets by transit spectroscopy.

  16. Near-infrared brightness of the Galilean satellites eclipsed in Jovian shadow: A new technique to investigate Jovian upper atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Tsumura, K. [Frontier Research Institute for Interdisciplinary Science, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Arimatsu, K.; Matsuura, S.; Shirahata, M.; Wada, T. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronoutical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210 (Japan); Egami, E. [Department of Astronomy, Arizona University, Tucson, AZ 85721 (United States); Hayano, Y.; Minowa, Y. [Hawaii Observatory, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); Honda, C. [Research Center for Advanced Information Science and Technology, Aizu Research Cluster for Space Science, The University of Aizu, Aizu-Wakamatsu, Fukushima 965-8589 (Japan); Kimura, J. [Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Kuramoto, K.; Takahashi, Y. [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Nakajima, K. [Department of Earth and Planetary Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Nakamoto, T. [Department of Earth and Planetary Sciences, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8551 (Japan); Surace, J., E-mail: tsumura@astr.tohoku.ac.jp [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-07-10

    Based on observations from the Hubble Space Telescope and the Subaru Telescope, we have discovered that Europa, Ganymede, and Callisto are bright around 1.5 μm even when not directly lit by sunlight. The observations were conducted with non-sidereal tracking on Jupiter outside of the field of view to reduce the stray light subtraction uncertainty due to the close proximity of Jupiter. Their eclipsed luminosity was 10{sup –6}-10{sup –7} of their uneclipsed brightness, which is low enough that this phenomenon has been undiscovered until now. In addition, Europa in eclipse was <1/10 of the others at 1.5 μm, a potential clue to the origin of the source of luminosity. Likewise, Ganymede observations were attempted at 3.6 μm by the Spitzer Space Telescope, but it was not detected, suggesting a significant wavelength dependence. It is still unknown why they are luminous even when in the Jovian shadow, but forward-scattered sunlight by hazes in the Jovian upper atmosphere is proposed as the most plausible candidate. If this is the case, observations of these Galilean satellites while eclipsed by the Jovian shadow provide us with a new technique to investigate the Jovian atmospheric composition. Investigating the transmission spectrum of Jupiter by this method is important for investigating the atmosphere of extrasolar giant planets by transit spectroscopy.

  17. Calculations of atmospheric transmittance in the 11 micrometer window for estimating skin temperature from VISSR infrared brightness temperatures

    Science.gov (United States)

    Chesters, D.

    1984-05-01

    An algorithm for calculating the atmospheric transmittance in the 10 to 20 micro m spectral band from a known temperature and dewpoint profile, and then using this transmittance to estimate the surface (skin) temperature from a VISSR observation in the 11 micro m window is presented. Parameterizations are drawn from the literature for computing the molecular absorption due to the water vapor continuum, water vapor lines, and carbon dioxide lines. The FORTRAN code is documented for this application, and the sensitivity of the derived skin temperature to variations in the model's parameters is calculated. The VISSR calibration uncertainties are identified as the largest potential source of error.

  18. THE OPTICAL AND NEAR-INFRARED TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ 1214b: FURTHER EVIDENCE FOR A METAL-RICH ATMOSPHERE

    International Nuclear Information System (INIS)

    We present an investigation of the transmission spectrum of the 6.5 M⊕ planet GJ 1214b based on new ground-based observations of transits of the planet in the optical and near-infrared, and on previously published data. Observations with the VLT + FORS and Magellan + MMIRS using the technique of multi-object spectroscopy with wide slits yielded new measurements of the planet's transmission spectrum from 0.61 to 0.85 μm, and in the J, H, and K atmospheric windows. We also present a new measurement based on narrow-band photometry centered at 2.09 μm with the VLT + HAWKI. We combined these data with results from a reanalysis of previously published FORS data from 0.78 to 1.00 μm using an improved data reduction algorithm, and previously reported values based on Spitzer data at 3.6 and 4.5 μm. All of the data are consistent with a featureless transmission spectrum for the planet. Our K-band data are inconsistent with the detection of spectral features at these wavelengths reported by Croll and collaborators at the level of 4.1σ. The planet's atmosphere must either have at least 70% H2O by mass or optically thick high-altitude clouds or haze to be consistent with the data.

  19. Use of near-infrared reflectance spectroscopy for shelf-life discrimination of green asparagus stored in a cool room under controlled atmosphere.

    Science.gov (United States)

    Sánchez, María-Teresa; Pérez-Marín, Dolores; Flores-Rojas, Katherine; Guerrero, José-Emilio; Garrido-Varo, Ana

    2009-04-30

    This study sought to evaluate the ability of near-infrared reflectance spectroscopy (NIRS) to classify intact green asparagus, in refrigerated storage under controlled atmosphere, by storage time and post-harvest treatments applied. A total of 468 green asparagus (Asparagus officinalis, L., cultivar UC-157) were sampled after 7, 14, 21 and 28 days of refrigerated storage (2 degrees C, 95% R.H.) under three controlled atmosphere (CA) treatments: air (21 kPa O(2)+0.3 kPa CO(2)), CA(1) (5 kPa O(2)+5 kPa CO(2)) and CA(2) (10 kPa O(2)+10kPa CO(2)). Two commercially available spectrophotometers were evaluated for this purpose: a scanning monochromator (SM) of 400-2500 nm and a combination of diode array and scanning monochromator (DASM) of 350-2500 nm. Models developed using partial least squares 2-discriminant analysis (PLS2-DA) correctly classified between 81-100% of samples by post-harvest storage time, depending on the instrument used. Using similar models, the DASM instrument correctly classified 85% of samples by post-harvest treatment, compared with 72% using the SM. These results confirmed that NIR spectroscopy, coupled with the use of chemometric techniques, provides a reliable, accurate method of predicting the shelf-life of asparagus under different storage conditions and as a function of post-harvest treatment applied; the method can be readily applied at industrial level. PMID:19203619

  20. Aura Atmospheric Data Products and Their Availability from NASA Goddard Earth Sciences DAAC

    Science.gov (United States)

    Ahmad, S.; Johnson, J.; Gopalan, A.; Smith, P.; Leptoukh, G.; Kempler, S.

    2004-01-01

    NASA's EOS-Aura spacecraft was launched successfully on July 15, 2004. The four instruments onboard the spacecraft are the Microwave Limb Sounder (MLS), the Ozone Monitoring Instrument (OMI), the Tropospheric Emission Spectrometer (TES), and the High Resolution Dynamics Limb Sounder (HBDLS). The Aura instruments are designed to gather earth sciences measurements across the ultraviolet, visible, infra-red, thermal and microwave regions of the electromagnetic spectrum. Aura will provide over 70 distinct standard atmospheric data products for use in ozone layer and surface UV-B monitoring, air quality forecast, and atmospheric chemistry and climate change studies (http://eosaura.gsfc.nasa.gov/). These products include earth-atmosphere radiances and solar spectral irradiances; total column, tropospheric, and profiles of ozone and other trace gases, surface W-B flux; clouds and aerosol characteristics; and temperature, geopotential height, and water vapor profiles. The MLS, OMI, and HIRDLS data products will be archived at the NASA Goddard Earth Sciences (GES) Distributed Active Archive Center (DAAC), while data from TES will be archived at NASA Langley Research Center DAAC. Some of the standard products which have gone through quick preliminary checks are already archived at the GES DAAC (http://daac.nsfc.nasa.gov/) and are available to the Aura science team and data validation team members for data validation; and to the application and visualization software developers, for testing their application modules. Once data are corrected for obvious calibration problems and partially validated using in-situ observations, they would be made available to the broader user community. This presentation will provide details of the whole suite of Aura atmospheric data products, and the time line of the availability of the rest of the preliminary products and of the partially validated provisional products. Software and took available for data access, visualization, and data

  1. Infrared spectroscopy of methoxyphenols involved as atmospheric secondary organic aerosol precursors: Gas-phase vibrational cross-sections

    Science.gov (United States)

    Cuisset, A.; Coeur, C.; Mouret, G.; Ahmad, W.; Tomas, A.; Pirali, O.

    2016-08-01

    Methoxyphenols are emitted in the atmosphere from biomass burning and recent works have shown the potential role of these oxygenated aromatic species in the formation of secondary organic aerosols. IR spectroscopic data that would enable their remote measurement in the atmosphere remain scarce in the literature. Room temperature Far-IR cross-sections of 4 methoxyphenols (2-methoxyphenol or guaiacol, 3-methoxyphenol, 4-methoxyphenol and 2,6-dimethoxyphenol or syringol) have been determined using the THz synchrotron radiation available at SOLEIL. Mid- and near-IR regions have also been investigated with a conventional Fourier transform IR setup and allowed to provide a set of vibrational cross-sections of the studied methoxyphenols. Finally, gas-phase cross sections of two nitroguaiacol isomers (4-nitroguaiacol and 5-nitroguaiacol), two intermediate products involved in the formation of secondary organic aerosols have been measured in the mid- and near-IR with a heated multi-pass cell. Harmonic and anharmonic density functional theory calculations were carried out for all the studied compounds and allowed a full assignment of the recorded rovibrational bands.

  2. Validation of the Aura Microwave Limb Sounder Temperature and Geopotential Height Measurements

    Science.gov (United States)

    Schwartz, M. J.; Lambert, A.; Manney, G. L.; Read, W. G.; Livesey, N. J.; Froidevaux, L.; Ao, C. O.; Bernath, P. F.; Boone, C. D.; Cofield, R. E.; Daffer, W. H.; Drouin, B. J.; Fetzer, E. J.; Fuller, R. A.; Jarnot, R. F.; Jiang, J. H.; Jiang, Y. B.; Knosp, B. W.; Krueger, K.; Li, J.-L. F.; Mlynczak, M. G.; Pawson, S.; Russell, J. M., III; Santee, M. L.; Snyder, W. V.

    2007-01-01

    This paper describes the retrievals algorithm used to determine temperature and height from radiance measurements by the Microwave Limb Sounder on EOS Aura. MLS is a "limbscanning" instrument, meaning that it views the atmosphere along paths that do not intersect the surface - it actually looks forwards from the Aura satellite. This means that the temperature retrievals are for a "profile" of the atmosphere somewhat ahead of the satellite. Because of the need to view a finite sample of the atmosphere, the sample spans a box about 1.5km deep and several tens of kilometers in width; the optical characteristics of the atmosphere mean that the sample is representative of a tube about 200-300km long in the direction of view. The retrievals use temperature analyses from NASA's Goddard Earth Observing System, Version 5 (GEOS-5) data assimilation system as a priori states. The temperature retrievals are somewhat deperrdezt on these a priori states, especially in the lower stratosphere. An important part of the validation of any new dataset involves comparison with other, independent datasets. A large part of this study is concerned with such comparisons, using a number of independent space-based measurements obtained using different techniques, and with meteorological analyses. The MLS temperature data are shown to have biases that vary with height, but also depend on the validation dataset. MLS data are apparently biased slightly cold relative to correlative data in the upper troposphere and slightly warm in the middle stratosphere. A warm MLS bias in the upper stratosphere may be due to a cold bias in GEOS-5 temperatures.

  3. Recovery of atmospheric water vapor total column abundance from imaging spectrometer data around 940 nm - Sensitivity analysis and application to Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) Data

    International Nuclear Information System (INIS)

    Two simple techniques to retrieve path precipitable water from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) high spectral resolution radiance data (Continuum Interpolated Band Ratio, CIBR, and Narrow/Wide ratio, N/W), using the 940 nm water absorption band, are compared. Since the shape and depth of the atmospheric water bands are influenced not only by the water present but also by surface (background) reflectance, atmospheric scattering, and instrument radiance by calibration, a sensitivity analysis was performed using the radiative transfer code LOWTRAN 7 to determine which one of these two approaches will provide a better estimate over land and water areas. The CIBR proved to be the technique less sensitive to perturbing effects, except for errors in visibility estimate. Both techniques were applied to AVIRIS radiance data acquired over Salton Sea, California. Resulting images confirmed that the used of a constant gray reflectance in the model led to a higher overestimation of the amount of water retrieved for N/W over vegetated areas. Validation was performed through comparison between an independent estimate of water vapor from concurrent Reagan sunphotometer measurements and AVIRIS estimates. Amounts retrieved using the N/W approach match more closely in situ measurements, even after adjusting model parameters for background reflectance, viewing geometry and type of aerosol at the site. The 13% underestimation observed for the CIBR was explained by small differences ΔL(λi) between AVIRIS and LOWTRAN 7 modeled radiances. Results from this study emphasizes the importance of accurate instrument calibration in flight and correct physical modeling of atmospheric absorptions

  4. Evidence of Convective Redistribution of Carbon Monoxide in Aura Tropospheric Emission Sounder (TES) and Microwave Limb Sounder (MLS) Observations

    Science.gov (United States)

    Manyin, Michael; Douglass, Anne; Schoeberl, Mark

    2010-01-01

    Vertical convective transport is a key element of the tropospheric circulation. Convection lofts air from the boundary layer into the free troposphere, allowing surface emissions to travel much further, and altering the rate of chemical processes such as ozone production. This study uses satellite observations to focus on the convective transport of CO from the boundary layer to the mid and upper troposphere. Our hypothesis is that strong convection associated with high rain rate regions leads to a correlation between mid level and upper level CO amounts. We first test this hypothesis using the Global Modeling Initiative (GMI) chemistry and transport model. We find the correlation is robust and increases as the precipitation rate (the strength of convection) increases. We next examine three years of CO profiles from the Tropospheric Emission Sounder (TES) and Microwave Limb Sounder (MLS) instruments aboard EOS Aura. Rain rates are taken from the Tropical Rainfall Measuring Mission (TRMM) 3B-42 multi-satellite product. Again we find a correlation between mid-level and upper tropospheric CO, which increases with rain rate. Our result shows the critical importance of tropical convection in coupling vertical levels of the troposphere in the transport of trace gases. The effect is seen most clearly in strong convective regions such as the Inter-tropical Convergence Zone.

  5. Planetcam: A Visible And Near Infrared Lucky-imaging Camera To Study Planetary Atmospheres And Solar System Objects

    Science.gov (United States)

    Sanchez-Lavega, Agustin; Rojas, J.; Hueso, R.; Perez-Hoyos, S.; de Bilbao, L.; Murga, G.; Ariño, J.; Mendikoa, I.

    2012-10-01

    PlanetCam is a two-channel fast-acquisition and low-noise camera designed for a multispectral study of the atmospheres of the planets (Venus, Mars, Jupiter, Saturn, Uranus and Neptune) and the satellite Titan at high temporal and spatial resolutions simultaneously invisible (0.4-1 μm) and NIR (1-2.5 μm) channels. This is accomplished by means of a dichroic beam splitter that separates both beams directing them into two different detectors. Each detector has filter wheels corresponding to the characteristic absorption bands of each planetary atmosphere. Images are acquired and processed using the “lucky imaging” technique in which several thousand images of the same object are obtained in a short time interval, coregistered and ordered in terms of image quality to reconstruct a high-resolution ideally diffraction limited image of the object. Those images will be also calibrated in terms of intensity and absolute reflectivity. The camera will be tested at the 50.2 cm telescope of the Aula EspaZio Gela (Bilbao) and then commissioned at the 1.05 m at Pic-duMidi Observatory (Franca) and at the 1.23 m telescope at Calar Alto Observatory in Spain. Among the initially planned research targets are: (1) The vertical structure of the clouds and hazes in the planets and their scales of variability; (2) The meteorology, dynamics and global winds and their scales of variability in the planets. PlanetCam is also expected to perform studies of other Solar System and astrophysical objects. Acknowledgments: This work was supported by the Spanish MICIIN project AYA2009-10701 with FEDER funds, by Grupos Gobierno Vasco IT-464-07 and by Universidad País Vasco UPV/EHU through program UFI11/55.

  6. Development of local atmospheric model for estimating solar irradiance in Peninsular Malaysia

    Science.gov (United States)

    Yeap, E. C.; Lau, A. M. S.; Busu, I.; Kanniah, K. D.; Rasib, A. W.; Kadir, W. H. W.

    2014-02-01

    Incoming solar irradiance covers a wide range of wavelengths with different intensities which drives almost every biological and physical cycle on earth at a selective wavelength. Estimation of the intensities of each wavelength for the solar irradiance on the earth surface provides a better way to understand and predict the radiance energy. It requires that the atmospheric and geometric input and the availability of atmospheric parameter is always the main concern in estimating solar irradiance. In this study, a local static atmospheric model for Peninsular Malaysia was built to provide the atmospheric parameters in the estimation of solar irradiance. Ten years of monthly Atmospheric Infrared Sounder (AIRS) average data (water vapor, temperature, humidity and pressure profile) of the Peninsular Malaysia was used for the building of the atmospheric model and the atmospheric model were assessed based on the measured meteorological data with RMSE of 4.7% and 0.7k for both humidity and temperature respectively. The atmospheric model were applied on a well-established radiative transfer model namely SMARTS2. Some modifications are required in order to include the atmospheric model into the radiative transfer model. The solar irradiance results were then assessed with measured irradiance data and the results show that both the radiative transfer model and atmospheric model were reliable with RMSE value of 0.5 Wm-2. The atmospheric model was further validated based on the measured meteorological data (temperature and humidity) provided by the Department of Meteorology, Malaysia and high coefficient of determination with R2 value of 0.99 (RMSE value = 4.7%) and 0.90 (RMSE value = 0.7k) were found for both temperature and humidity respectively.

  7. Development of local atmospheric model for estimating solar irradiance in Peninsular Malaysia

    International Nuclear Information System (INIS)

    Incoming solar irradiance covers a wide range of wavelengths with different intensities which drives almost every biological and physical cycle on earth at a selective wavelength. Estimation of the intensities of each wavelength for the solar irradiance on the earth surface provides a better way to understand and predict the radiance energy. It requires that the atmospheric and geometric input and the availability of atmospheric parameter is always the main concern in estimating solar irradiance. In this study, a local static atmospheric model for Peninsular Malaysia was built to provide the atmospheric parameters in the estimation of solar irradiance. Ten years of monthly Atmospheric Infrared Sounder (AIRS) average data (water vapor, temperature, humidity and pressure profile) of the Peninsular Malaysia was used for the building of the atmospheric model and the atmospheric model were assessed based on the measured meteorological data with RMSE of 4.7% and 0.7k for both humidity and temperature respectively. The atmospheric model were applied on a well-established radiative transfer model namely SMARTS2. Some modifications are required in order to include the atmospheric model into the radiative transfer model. The solar irradiance results were then assessed with measured irradiance data and the results show that both the radiative transfer model and atmospheric model were reliable with RMSE value of 0.5 Wm−2. The atmospheric model was further validated based on the measured meteorological data (temperature and humidity) provided by the Department of Meteorology, Malaysia and high coefficient of determination with R2 value of 0.99 (RMSE value = 4.7%) and 0.90 (RMSE value = 0.7k) were found for both temperature and humidity respectively

  8. Near-infrared Brightness of the Galilean Satellites Eclipsed in Jovian Shadow: A New Technique to Investigate Jovian Upper Atmosphere

    CERN Document Server

    Tsumura, K; Egami, E; Hayano, Y; Honda, C; Kimura, J; Kuramoto, K; Matsuura, S; Minowa, Y; Nakajima, K; Nakamoto, T; Shirahata, M; Surace, J; Takahashi, Y; Wada, T

    2014-01-01

    We have discovered that Europa, Ganymede and Callisto are bright around 1.5 {\\mu}m even when not directly lit by sunlight, based on observations from the Hubble Space Telescope and the Subaru Telescope. The observations were conducted with non-sidereal tracking on Jupiter outside of the field of view to reduce the stray light subtraction uncertainty due to the close proximity of Jupiter. Their eclipsed luminosity was $10^{-6}$-$10^{-7}$ of their uneclipsed brightness, which is low enough that this phenomenon has been undiscovered until now. In addition, Europa in eclipse was <1/10 of the others at 1.5 {\\mu}m, a potential clue to the origin of the source of luminosity. Likewise, Ganymede observations were attempted at 3.6 {\\mu}m by the Spitzer Space Telescope but it was not detected, suggesting a significant wavelength dependence. The reason why they are luminous even when in the Jovian shadow is still unknown, but forward-scattered sunlight by haze in the Jovian upper atmosphere is proposed as the most pla...

  9. Use of Total Precipitable Water Classification of A Priori Error and Quality Control in Atmospheric Temperature and Water Vapor Sounding Retrieval

    Institute of Scientific and Technical Information of China (English)

    Eun-Han KWON; Jun LI; Jinlong LI; B. J. SOHN; Elisabeth WEISZ

    2012-01-01

    This study investigates the use of dynamic a priori error information according to atmospheric moistness and the use of quality controls in temperature and water vapor profile retrievals from hyperspectral infrared (IR) sounders.Temperature and water vapor profiles are retrieved from Atmospheric InfraRed Sounder (AIRS) radiance measurements by applying a physical iterative method using regression retrieval as the first guess. Based on the dependency of first-guess errors on the degree of atmospheric moistness,the a priori first-guess errors classified by total precipitable water (TPW) are applied in the AIRS physical retrieval procedure.Compared to the retrieval results from a fixed a priori error,boundary layer moisture retrievals appear to be improved via TPW classification of a priori first-guess errors.Six quality control (QC)tests,which check non-converged or bad retrievals,large residuals,high terrain and desert areas,and large temperature and moisture deviations from the first guess regression retrieval,are also applied in the AIRS physical retrievals.Significantly large errors are found for the retrievals rejected by these six QCs,and the retrieval errors are substantially reduced via QC over land,which suggest the usefulness and high impact of the QCs,especially over land.In conclusion,the use of dynamic a priori error information according to atmospheric moistness,and the use of appropriate QCs dealing with the geographical information and the deviation from the first-guess as well as the conventional inverse performance are suggested to improve temperature and moisture retrievals and their applications.

  10. Satellite Sounder Data Assimilation for Improving Alaska Region Weather Forecast

    Science.gov (United States)

    Zhu, Jiang; Stevens, E.; Zavodsky, B. T.; Zhang, X.; Heinrichs, T.; Broderson, D.

    2014-01-01

    Data assimilation has been demonstrated very useful in improving both global and regional numerical weather prediction. Alaska has very coarser surface observation sites. On the other hand, it gets much more satellite overpass than lower 48 states. How to utilize satellite data to improve numerical prediction is one of hot topics among weather forecast community in Alaska. The Geographic Information Network of Alaska (GINA) at University of Alaska is conducting study on satellite data assimilation for WRF model. AIRS/CRIS sounder profile data are used to assimilate the initial condition for the customized regional WRF model (GINA-WRF model). Normalized standard deviation, RMSE, and correlation statistic analysis methods are applied to analyze one case of 48 hours forecasts and one month of 24-hour forecasts in order to evaluate the improvement of regional numerical model from Data assimilation. The final goal of the research is to provide improved real-time short-time forecast for Alaska regions.

  11. Deep thermal infrared imaging of HR 8799 bcde: new atmospheric constraints and limits on a fifth planet

    International Nuclear Information System (INIS)

    We present new L' (3.8 μm) and Brα (4.05 μm) data and reprocessed archival L' data for the young, planet-hosting star HR 8799 obtained with Keck/NIRC2, VLT/NaCo, and Subaru/IRCS. We detect all four HR 8799 planets in each data set at a moderate to high signal-to-noise ratio (S/N ≳ 6-15). We fail to identify a fifth planet, 'HR 8799 f', at r < 15 AU at a 5σ confidence level: one suggestive, marginally significant residual at 0.''2 is most likely a point-spread function artifact. Assuming companion ages of 30 Myr and the Baraffe planet cooling models, we rule out an HR 8799 f with a mass of 5 MJ (7 MJ ), 7 MJ (10 MJ ), or 12 MJ (13 MJ ) at r proj ∼ 12 AU, 9 AU, and 5 AU, respectively. All four HR 8799 planets have red early T dwarf-like L' – [4.05] colors, suggesting that their spectral energy distributions peak in between the L' and M' broadband filters. We find no statistically significant difference in HR 8799 cde's color. Atmosphere models assuming thick, patchy clouds appear to better match HR 8799 bcde's photometry than models assuming a uniform cloud layer. While non-equilibrium carbon chemistry is required to explain HR 8799 b and c's photometry/spectra, evidence for it from HR 8799 d and e's photometry is weaker. Future, deep-IR spectroscopy/spectrophotometry with the Gemini Planet Imager, SCExAO/CHARIS, and other facilities may clarify whether the planets are chemically similar or heterogeneous.

  12. Technical Note: Improved total atmospheric water vapour amount determination from near-infrared filter measurements with sun photometers

    Directory of Open Access Journals (Sweden)

    F. Mavromatakis

    2007-09-01

    Full Text Available In this work we explore the effect of the contribution of the solar spectrum to the recorded signal in wavelengths outside the typical 940-nm filter's bandwidth. We employ gaussian-shaped filters as well as actual filter transmission curves, mainly AERONET data, to study the implications imposed by the non-zero out-of-band contribution to the coefficients used to derive precipitable water from the measured water vapour band transmittance. Published parameterized transmittance functions are applied to the data to determine the filter coefficients. We also introduce an improved, three-parameter, fitting function that can describe the theoretical data accurately, with significantly less residual effects than with the existing functions. The moderate-resolution SMARTS radiative transfer code is used to predict the incident spectrum outside the filter bandpass for different atmospheres, solar geometries and aerosol optical depths. The high-resolution LBLRTM radiative transfer code is used to calculate the water vapour transmittance in the 940-nm band. The absolute level of the out-of-band transmittance has been chosen to range from 10−6 to 10−4, and typical response curves of commercially available silicon photodiodes are included into the calculations.

    It is shown that if the out-of-band transmittance effect is neglected, as is generally the case, then the derived columnar water vapour is mainly underestimated by a few percents. The actual error depends on the specific out-of-band transmittance, optical air mass of observation and water vapour amount. Further investigations will use experimental data from field campaigns to validate these findings.

  13. Deep thermal infrared imaging of HR 8799 bcde: new atmospheric constraints and limits on a fifth planet

    Energy Technology Data Exchange (ETDEWEB)

    Currie, Thayne; Cloutier, Ryan; Jayawardhana, Ray [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Burrows, Adam [Department of Astrophysical Science, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 (United States); Girard, Julien H. [European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago (Chile); Fukagawa, Misato [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Sorahana, Satoko [Department of Astronomy, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kuchner, Marc [Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 667, Greenbelt, MD 20771 (United States); Kenyon, Scott J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Madhusudhan, Nikku [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Itoh, Yoichi [Nishi-Harima Astronomical Observatory, Center for Astronomy, University of Hyago, 407-2 Nishigaichi, Sayo, Hyogo 679-5313 (Japan); Matsumura, Soko [School of Engineering, Physics, and Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom); Pyo, Tae-Soo [National Astronomical Observatory of Japan, 650 N. Aohoku Place, Hilo, HI 96720 (United States)

    2014-11-10

    We present new L' (3.8 μm) and Brα (4.05 μm) data and reprocessed archival L' data for the young, planet-hosting star HR 8799 obtained with Keck/NIRC2, VLT/NaCo, and Subaru/IRCS. We detect all four HR 8799 planets in each data set at a moderate to high signal-to-noise ratio (S/N ≳ 6-15). We fail to identify a fifth planet, 'HR 8799 f', at r < 15 AU at a 5σ confidence level: one suggestive, marginally significant residual at 0.''2 is most likely a point-spread function artifact. Assuming companion ages of 30 Myr and the Baraffe planet cooling models, we rule out an HR 8799 f with a mass of 5 M{sub J} (7 M{sub J} ), 7 M{sub J} (10 M{sub J} ), or 12 M{sub J} (13 M{sub J} ) at r {sub proj} ∼ 12 AU, 9 AU, and 5 AU, respectively. All four HR 8799 planets have red early T dwarf-like L' – [4.05] colors, suggesting that their spectral energy distributions peak in between the L' and M' broadband filters. We find no statistically significant difference in HR 8799 cde's color. Atmosphere models assuming thick, patchy clouds appear to better match HR 8799 bcde's photometry than models assuming a uniform cloud layer. While non-equilibrium carbon chemistry is required to explain HR 8799 b and c's photometry/spectra, evidence for it from HR 8799 d and e's photometry is weaker. Future, deep-IR spectroscopy/spectrophotometry with the Gemini Planet Imager, SCExAO/CHARIS, and other facilities may clarify whether the planets are chemically similar or heterogeneous.

  14. Cirrus cloud optical and microphysical properties determined from AIRS infrared spectra

    Science.gov (United States)

    Yue, Qing; Liou, K. N.

    2009-03-01

    We developed an efficient thermal infrared radiative transfer model on the basis of the delta-four-stream approximation to facilitate high-spectral-resolution remote sensing applications under cirrus cloudy conditions in the Atmospheric Infrared Sounder (AIRS) data. Numerical experiments demonstrated that sensitivity in the 800-1130 cm-1 thermal infrared window spectral region is sufficiently distinct for the inference of cirrus optical depth and ice crystal mean effective size and shape factor. We analyzed 312 nighttime cirrus pixels in two AIRS granules over ARM TWP sites and applied the radiative transfer model to these cases to determine cirrus optical depth and ice crystal mean effective size, based on a look-up table approach. The retrieval program has been evaluated through an error budget analysis and validation effort by comparing AIRS-retrieved results with those determined from ground-based millimeter-wave cloud radar data at ARM TWP sites, for five AIRS pixels that were collocated and coincident with ground-based measurements.

  15. Validation of ozone data from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES)

    Science.gov (United States)

    Imai, Koji; Manago, Naohiro; Mitsuda, Chihiro; Naito, Yoko; Nishimoto, Eriko; Sakazaki, Takatoshi; Fujiwara, Masatomo; Froidevaux, Lucien; Clarmann, Thomas; Stiller, Gabriele P.; Murtagh, Donal P.; Rong, Ping-Ping; Mlynczak, Martin G.; Walker, Kaley A.; Kinnison, Douglas E.; Akiyoshi, Hideharu; Nakamura, Tetsu; Miyasaka, Takayuki; Nishibori, Toshiyuki; Mizobuchi, Satoko; Kikuchi, Ken-Ichi; Ozeki, Hiroyuki; Takahashi, Chikako; Hayashi, Hiroo; Sano, Takuki; Suzuki, Makoto; Takayanagi, Masahiro; Shiotani, Masato

    2013-06-01

    The Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space Station provided global measurements of ozone profiles in the middle atmosphere from 12 October 2009 to 21 April 2010. We present validation studies of the SMILES version 2.1 ozone product based on coincidence statistics with satellite observations and outputs of chemistry and transport models (CTMs). Comparisons of the stratospheric ozone with correlative data show agreements that are generally within 10%. In the mesosphere, the agreement is also good and better than 30% even at a high altitude of 73 km, and the SMILES measurements with their local time coverage also capture the diurnal variability very well. The recommended altitude range for scientific use is from 16 to 73 km. We note that the SMILES ozone values for altitude above 26 km are smaller than some of the correlative satellite datasets; conversely the SMILES values in the lower stratosphere tend to be larger than correlative data, particularly in the tropics, with less than 8% difference below ~24 km. The larger values in the lower stratosphere are probably due to departure of retrieval results between two detection bands at altitudes below 28 km; it is ~3% at 24 km and is increasing rapidly down below.

  16. Design and Implementation of a Mechanical Control System for the Scanning Microwave Limb Sounder

    Science.gov (United States)

    Bowden, William

    2011-01-01

    The Scanning Microwave Limb Sounder (SMLS) will use technological improvements in low noise mixers to provide precise data on the Earth's atmospheric composition with high spatial resolution. This project focuses on the design and implementation of a real time control system needed for airborne engineering tests of the SMLS. The system must coordinate the actuation of optical components using four motors with encoder readback, while collecting synchronized telemetric data from a GPS receiver and 3-axis gyrometric system. A graphical user interface for testing the control system was also designed using Python. Although the system could have been implemented with a FPGA-based setup, we chose to use a low cost processor development kit manufactured by XMOS. The XMOS architecture allows parallel execution of multiple tasks on separate threads-making it ideal for this application and is easily programmed using XC (a subset of C). The necessary communication interfaces were implemented in software, including Ethernet, with significant cost and time reduction compared to an FPGA-based approach. For these reasons, the XMOS technology is an attractive, cost effective, alternative to FPGA-based technologies for this design and similar rapid prototyping projects.

  17. OPTICAL-TO-NEAR-INFRARED SIMULTANEOUS OBSERVATIONS FOR THE HOT URANUS GJ3470b: A HINT OF A CLOUD-FREE ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Fukui, Akihiko; Yanagisawa, Kenshi; Kuroda, Daisuke; Shimizu, Yasuhiro; Izumiura, Hideyuki [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan); Narita, Norio; Takahashi, Yasuhiro H.; Kawauchi, Kiyoe; Nagayama, Shogo [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kurosaki, Kenji; Ikoma, Masahiro [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-0033 (Japan); Ohnuki, Hiroshi [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); Onitsuka, Masahiro; Suenaga, Takuya [The Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hirano, Teruyuki [Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ohta, Kouji [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake, Sakyo, Kyoto 606-8502 (Japan); Yoshida, Michitoshi [Hiroshima Astrophysical Science Center, Hiroshima University 1-3-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kawai, Nobuyuki, E-mail: afukui@oao.nao.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro, Tokyo 152-8551 (Japan)

    2013-06-20

    We present optical (g', R{sub c}, and I{sub c}) to near-infrared (J) simultaneous photometric observations for a primary transit of GJ3470b, a Uranus-mass transiting planet around a nearby M dwarf, by using the 50 cm MITSuME telescope and the 188 cm telescope, both at the Okayama Astrophysical Observatory. From these data, we derive the planetary mass, radius, and density as 14.1 {+-} 1.3 M{sub Circled-Plus }, 4.32{sup +0.21}{sub -0.10} R{sub Circled-Plus }, and 0.94 {+-} 0.12 g cm{sup -3}, respectively, thus confirming the low density that was reported by Demory et al. based on the Spitzer/IRAC 4.5 {mu}m photometry (0.72{sup +0.13}{sub -0.12} g cm{sup -3}). Although the planetary radius is about 10% smaller than that reported by Demory et al., this difference does not alter their conclusion that the planet possesses a hydrogen-rich envelope whose mass is approximately 10% of the planetary total mass. On the other hand, we find that the planet-to-star radius ratio (R{sub p} /R{sub s} ) in the J band (0.07577{sup +0.00072}{sub -0.00075}) is smaller than that in the I{sub c} (0.0802 {+-} 0.0013) and 4.5 {mu}m (0.07806{sup +0.00052}{sub -0.00054}) bands by 5.8% {+-} 2.0% and 2.9% {+-} 1.1%, respectively. A plausible explanation for the differences is that the planetary atmospheric opacity varies with wavelength due to absorption and/or scattering by atmospheric molecules. Although the significance of the observed R{sub p} /R{sub s} variations is low, if confirmed, this fact would suggest that GJ3470b does not have a thick cloud layer in the atmosphere. This property would offer a wealth of opportunity for future transmission-spectroscopic observations of this planet to search for certain molecular features, such as H{sub 2}O, CH{sub 4}, and CO, without being prevented by clouds.

  18. Measurement of forest ecosystem-atmosphere exchange of delta-carbon-13--carbon dioxide using Fourier transform infrared spectroscopy and disjunct eddy covariance

    Science.gov (United States)

    Cambaliza, Maria Obiminda L.

    The measurement of the stable isotopic content and isotopic flux of atmospheric carbon dioxide is important for understanding the carbon budget on ecosystem, regional, and global spatial scales. Conventional measurements of the isotopic composition of atmospheric CO2 involve laboratory mass spectrometry analysis of grab samples from the field, which limits the location, collection frequency and throughput of samples. More technologically advanced methods (e.g. tunable diode laser spectroscopy) suffer from interferences with other chemical species. We have developed a new measurement method based on Fourier-transform infrared spectroscopy (FTIR) and disjunct eddy covariance (DEC) for fast, continuous, real-time measurement of the carbon isotopic composition of atmospheric CO2. Molecular absorption is measured in the 2100 to 2500 cm -1 spectral region of the 13CO2 and 12CO2 vibration-rotation bands with concentrations of both isotopologues used to determine delta13C. We demonstrate the capability of this new technique in a managed poplar forest near Boardman, Oregon with measurements during the summers of 2005 and 2006 from a 22-meter tower in a 16-m forest canopy. Long-term calibration using reference gas cylinders yielded field accuracy and precision for the forest measurements of 0.5‰ and 0.8‰, respectively, for the 45-second cycle time between samples. The signature of ecosystem respiration derived from the nighttime vertical profile measurements of CO2-delta13C was --26.6‰, about 2‰ more enriched than the isotopic composition of measured bulk leaf samples from the forest. Ecosystem respired CO 2 was ˜1.6‰ more enriched than soil-respired CO2. A comparison of the FTIR -- DEC total CO2 fluxes against standard eddy covariance measurements showed excellent (10%) agreement. FTIR-DEC measurement of the CO2 isoflux enabled the estimation of the mean carbon isotope ratio of the photosynthetic flux (deltaP). The average deltaP (-24.9‰) was 13C

  19. Calibration of Suomi national polar-orbiting partnership advanced technology microwave sounder

    Science.gov (United States)

    Weng, Fuzhong; Zou, Xiaolei; Sun, Ninghai; Yang, Hu; Tian, Miao; Blackwell, William J.; Wang, Xiang; Lin, Lin; Anderson, Kent

    2013-10-01

    The Suomi National Polar-Orbiting Partnership (NPP) satellite was launched on 28 October 2011 and carries the Advanced Technology Microwave Sounder (ATMS) on board. ATMS is a cross-track scanning instrument observing in 22 channels at frequencies ranging from 23 to 183 GHz, permitting the measurements of the atmospheric temperature and moisture under most weather conditions. In this study, the ATMS radiometric calibration algorithm used in the operational system is first evaluated through independent analyses of prelaunch thermal vacuum data. It is found that the ATMS peak nonlinearity for all the channels is less than 0.5 K, which is well within the specification. For the characterization of the ATMS instrument sensitivity or noise equivalent differential temperatures (NEDT), both standard deviation and Allan variance of warm counts are computed and compared. It is shown that NEDT derived from the standard deviation is about three to five times larger than that from the Allan variance. The difference results from a nonstationary component in the standard deviation of warm counts. The Allan variance is better suited than the standard deviation for describing NEDT. In the ATMS sensor brightness temperature data record (SDR) processing algorithm, the antenna gain efficiencies of main beam, cross-polarization beam, and side lobes must be derived accurately from the antenna gain distribution function. However, uncertainties remain in computing the efficiencies at ATMS high frequencies. Thus, ATMS antenna brightness temperature data records (TDR) at channels 1 to 15 are converted to SDR with the actual beam efficiencies whereas those for channels 16 to 22 are only corrected for the near-field sidelobe contributions. The biases of ATMS SDR measurements to the simulations are consistent between GPS RO and NWP data and are generally less than 0.5 K for those temperature-sounding channels where both the forward model and input atmospheric profiles are reliable.

  20. Remote sensing of greenhouse gases (CO2 and CH4) using hyperspectral observations in the thermal infrared

    Science.gov (United States)

    Crevoisier, Cyril; Chedin, Alain; Nobileau, Delphine; Armante, Raymond; Thonat, Thibaud; Scott, Noelle A.

    Densely sampling the atmosphere in time and space, satellite measurements of the distribution of global atmospheric CO2 concentration could in principle provide a way to constrain atmo-spheric inversions of CO2 surface fluxes. Until the recent launch of the first dedicated CO2 observing instrument JAXA/GOSAT in January 2009, information on CO2 and other green-house gas atmospheric distribution have been obtained for several years from thermal infrared sounders, such as the Atmospheric Infrared Sounder (AIRS) launched onboard the NASA/Aqua satellite in May 2002 or the Infrared Atmospheric Sounding Interferometer (IASI) launched on-board the European MetOp platform in October 2006. We use coupled observations in the thermal infrared from IASI, and in the microwave from the Advanced Microwave Sounding Unit (AMSU), also launched onboard MetOp, to retrieve mid-to-upper tropospheric contents of carbon dioxide (CO2) and methane (CH4) in clear-sky conditions, in the tropics. Thermal observations, sensitive to both temperature and either CO2 or CH4, are used in conjunction with microwave observations, only sensitive to temperature, to decorrelate both signals through a non-linear inference scheme based on neural networks. A key point of this approach is that no use is made of prior information in terms of gas seasonality, trend, or geographical patterns. The precision of the IASI retrieval is estimated to be about 2 ppmv (less than 1 Features of the retrieved CO2-CH4 space-time distributions include: (1) a CO2 trend of 2.1 ppmv.yr-1 in average, and a CH4 trend of 10 ppbv.yr-1 in the last couple of years, which confirms the recent increase of methane detected at surface stations; (2) a strong seasonal cycle in the northern tropics, and a lower seasonal cycle in the southern tropics, in agreement with in-situ measurements; in particular, comparison between AIRS and IASI retrievals highlights the time-lag of CO2 cycle while transported from the surface to the upper troposphere

  1. Comparison of CO2 retrievals from IASI-A, IASI-B and GOSAT in the thermal infrared for nearly coincident measurements over the Arctic ocean in summer

    Science.gov (United States)

    Camy-Peyret, Claude; Bureau, Jerome; Payan, Sebastien

    2015-04-01

    The capabilities to retrieve reliable information on the concentration of greenhouse gases in the lower atmosphere from thermal infrared (TIR) spectra collected by nadir sounders is still to be assessed. We have selected the two months period of July-August in the high latitude polar region where it is possible to observe almost coincident or superimposed footprints (IFOV) of the three infrared sounders considered in this study, namely IASI-A, IASI-B (on the MetOp platforms) and TANSO-FTS (on GOSAT). Retrievals of the column averaged mixing ratio of carbon dioxide XCO2 (and of the surface temperature) have been performed for three years i.e. 2010, 2013 and 2014 over Arctic waters. The summer period was chosen because ice free IFOVs (in the latitude band 68N to 82N) can be selected for which retrievals are less sensitive to surface inhomogeneity (as compared to IFOVs located over land). The emissivity of sea water is also better constrained. The inversion configuration (using the atmospheric window covering the so-called CO2 laser band in the interval 940-980 cm-1) will be described. The sensitivity of the retrieved XCO2 to the different layers of the lower atmosphere as a function of thermal contrast, temperature and humidity profiles will be presented. The precision/accuracy of the retrieved XCO2 will be discussed and compared between sounders. The CO2 trends is clearly captured over the years analysed in this work. The retrieved values will be compared to similar XCO2 products available from other sources (Leicester Univ., NIES, SRON/KIT). Some remaining spectroscopic issues in the vicinity of 948 cm-1 have been identified and circumvented. The retrieved sea surface temperature Tsurf used as a control variable is also providing an additional check of the performances of the retrievals and is compared to the Eumetsat IASI Tsurf product. These results are interesting starting points for preparing future missions like IASI-NG on MetOp-SG as well as GOSAT-2.

  2. An Anomaly Correlation Skill Score for the Evaluation of the Performance of Hyperspectral Infrared Sounders

    Science.gov (United States)

    Aumann, Hartmut H.; Manning, Evan; Barnet, Chris; Maddy, Eric; Blackwell, William

    2009-01-01

    With the availability of very accurate forecasts, the metric of accuracy alone for the evaluation of the performance of a retrieval system can produce misleading results. A useful characterization of the quality of a retrieval system and its potential to contribute to an improved weather forecast is its skill, which we define as the ability to make retrievals of geophysical parameters which are closer to the truth than the six hour forecast, when the truth differs significantly from the forecast. We illustrate retrieval skill using one day of AMSU and AIRS data with three different retrieval algorithms, which result in retrievals for more than 90% of the potential retrievals under clear and cloudy conditions. Two of the three algorithms have better than 1 K rms "RAOB quality" accuracy on the troposphere, but only one has skill between 900 and 100 mb. AIRS was launched on the EOS Aqua spacecraft in May 2002 into a 705 km polar sun-synchronous orbit with accurately maintained 1:30 PM ascending node. Essentially uninterrupted data are freely available since September 2002.

  3. A reference atmosphere for LAWS trade studies - An update

    Science.gov (United States)

    Wood, S. A.; Emmitt, G. D.

    1991-01-01

    The baseline SNR and LOS velocity errors for two proposed Laser Atmospheric Wind Sounder (LAWS) satellite orbits are examined with the aid of a reference atmosphere from the LAWS Simulation Model. It is shown on the basis of a tropical maritime atmosphere that obtaining wind information in the midlevels will be difficult unless better signal processing is possible and/or subvisual cirrus is present. Backscatter probability diagrams for a satellite at 500 and 705 km are presented.

  4. Atmospheric radiation measurement program facilities newsletter, June 2002.; TOPICAL

    International Nuclear Information System (INIS)

    ARM Intensive Operational Period Scheduled to Validate New NASA Satellite-Beginning in July, all three ARM sites (Southern Great Plains[SGP], North Slope of Alaska, and Tropical Western Pacific; Figure 1) will participate in the AIRS Validation IOP. This three-month intensive operational period (IOP) will validate data collected by the satellite-based Atmospheric Infrared Sounder (AIRS) recently launched into space. On May 4, the National Aeronautics and Space Administration (NASA) launched Aqua, the second spacecraft in the Earth Observing System (EOS) series. The EOS satellites monitor Earth systems including land surfaces, oceans, the atmosphere, and ice cover. The first EOS satellite, named Terra, was launched in December 1999. The second EOS satellite is named Aqua because its primary focus is understanding Earth's water cycle through observation of atmospheric moisture, clouds, temperature, ocean surface, precipitation, and soil moisture. One of the instruments aboard Aqua is the AIRS, built by the Jet Propulsion Laboratory, a NASA agency. The AIRS Validation IOP complements the ARM mission to improve understanding of the interactions of clouds and atmospheric moisture with solar radiation and their influence on weather and climate. In support of satellite validation IOP, ARM will launch dedicated radiosondes at all three ARM sites while the Aqua satellite with the AIRS instrument is orbiting overhead. These radiosonde launches will occur 45 minutes and 5 minutes before selected satellite overpasses. In addition, visiting scientists from the Jet Propulsion Laboratory will launch special radiosondes to measure ozone and humidity over the SGP site. All launches will generate ground-truth data to validate satellite data collected simultaneously. Data gathered daily by ARM meteorological and solar radiation instruments will complete the validation data sets. Data from Aqua-based instruments, including AIRS, will aid in weather forecasting, climate modeling, and

  5. New Asia Dust Storm Detection Method Based on the Thermal Infrared Spectral Signature

    Directory of Open Access Journals (Sweden)

    Hui Xu

    2014-12-01

    Full Text Available As hyperspectral instruments can provide the detailed spectral information, a new spectral similarity method for detecting and differentiating dust from non-dust scenes using the Atmospheric Infrared Sounder (AIRS observations has been developed. The detection is based on a pre-defined Dust Spectral Similarity Index (DSSI, which was calculated from the accumulated brightness temperature differences between selected 16 AIRS observation channels, in the thermal infrared region of 800–1250 cm−1. It has been demonstrated that DSSI can effectively separate the dust from non-dust by elevating dust signals. For underlying surface covered with dust, the DSSI tends to show values close to 1.0. However, the values of DSSI for clear sky surfaces or clouds (ice and water are basically lower than those of dust, as their spectrums have significant differences with dust. To evaluate this new simple DSSI dust detection algorithm, several Asia dust events observed in northern China were analyzed, and the results agree favorably with those from the Moderate resolution Imaging Spectro radiometer (MODIS and Cloud Aerosol LiDAR with Orthogonal Polarization (CALIOP observations.

  6. Characterization of geolocation accuracy of Suomi NPP Advanced Technology Microwave Sounder measurements

    Science.gov (United States)

    Han, Yang; Weng, Fuzhong; Zou, Xiaolei; Yang, Hu; Scott, Deron

    2016-05-01

    The Advanced Technology Microwave Sounder (ATMS) onboard Suomi National Polar-orbiting Partnership satellite has 22 channels at frequencies ranging from 23 to 183 GHz for probing the atmospheric temperature and moisture under all weather conditions. As part of the ATMS calibration and validation activities, the geolocation accuracy of ATMS data must be well characterized and documented. In this study, the coastline crossing method (CCM) and the land-sea fraction method (LFM) are utilized to characterize and quantify the ATMS geolocation accuracy. The CCM is based on the inflection points of the ATMS window channel measurements across the coastlines, whereas the LFM collocates the ATMS window channel data with high-resolution land-sea mask data sets. Since the ATMS measurements provide five pairs of latitude and longitude data for K, Ka, V, W, and G bands, respectively, the window channels 1, 2, 3, 16, and 17 from each of these five bands are chosen for assessing the overall geolocation accuracy. ATMS geolocation errors estimated from both methods are generally consistent from 40 cases in June 2014. The ATMS along-track (cross-track) errors at nadir are within ±4.2 km (±1.2 km) for K/Ka, ±2.6 km (±2.7 km) for V bands, and ±1.2 km (±0.6 km) at W and G bands, respectively. At the W band, the geolocation errors derived from both algorithms are probably less reliable due to a reduced contrast of brightness temperatures in coastal areas. These estimated ATMS along-track and cross-track geolocation errors are well within the uncertainty requirements for all bands.

  7. Seasonal and diel patterns in sedimentary flux of krill fecal pellets recorded by an echo sounder

    KAUST Repository

    Røstad, Anders

    2013-11-01

    We used a moored upward-facing 200 kHz echo sounder to address sedimentation of fecal pellets (FPs) from dielly migrating Meganyctiphanes norvegica. The echo sounder was located on the bottom at 150 m depth in the Oslofjord, Norway, and was cabled to shore for continuous measurements during winter and spring. Records of sinking pellets were for the first time observed with an echo sounder. Seasonal patterns of sedimentation of krill FPs were strongly correlated with data from continuous measurement of fluorescence, which illustrate the development of the spring bloom. Sedimenting particles were first observed as fluorescence values started to increase at the end of February and continued to increase until the bloom suddenly culminated at the end of March. This collapse of the bloom was detected on the echo sounder as a pulse of slowly sinking acoustic targets over a 2 d period. Prior to this event, there was a strong diel pattern in sedimentation, which correlated, with some time lag, with the diel migration of krill foraging at night near the surface. Pellet average sinking speeds ranged between 423 m d−1 and 804 m d−1, with a strong relation to pellet target strength, which is an acoustic proxy for size. This novel approach shows that echo sounders may be a valuable tool in studies of vertical pellet flux and, thereby, carbon flux, providing temporal resolution and direct observation of the sedimentation process, which are not obtained from standard methods.

  8. TIDDBIT HF Doppler Sounder Measurements of TIDs During the Wallops Island Rocket Launch of October 2007

    Science.gov (United States)

    Reynolds, A.; Crowley, G.; Rodrigues, F.; Earle, G.; Bullett, T.; Bishop, R.

    2008-12-01

    The TID Detector Built In Texas (TIDDBIT) sounder was deployed on the East Coast near Wallops Island to support a rocket launch in October 2007. The purpose of the rocket experiment was to study mid-latitude spread-F (MSF), and TIDDBIT provided information on the TID characteristics during the launch and for several days surrounding the launch. The sounder data confirm that waves were present during the rocket launch. This presentation reviews the TIDDBIT results from the experiment, contrasting data collected on different days, and from the same dates a year earlier. HF Doppler sounders represent a low-cost and low- maintenance solution for monitoring acoustic and gravity wave activity in the F-region ionosphere. HF Doppler sounders together with modern data analysis techniques provide both horizontal and vertical phase trace velocities across the entire TID spectrum from periods of 30-s to several hours. ASTRA has extensive experience with HF systems, and is currently building TIDDBIT sounders in New Mexico, and Peru.

  9. Sounder-updated statistical model predictions of maximum usable frequency for HF sky wave predictions

    Science.gov (United States)

    Reilly, M. H.; Daehler, M.

    1985-10-01

    Measured solar parameters, such as sunspot number or 10.7 cm flux, have traditionally been used as inputs to drive statistical model predictions of maximum usable frequencies (MUFs) on HF radio sky wave paths of interest. Much greater accuracy can be obtained by using ionospheric sounder inputs to drive or update statistical model predictions, and this is demonstrated here using oblique-incidence sounder data from the DoD Solid Shield exercises on May 12-14, 1981. From analysis of ionograms collected for several paths every fifteen minutes, it is found that deployment of a reasonable number of sounders in a large area, in order to update the simple statistical model, MINIMUF, yields MUF prediction capability on unsounded communication paths in the area within 0.4 MHz rms error. This value is obtained from real-time updating and a spatial interpolation process developed here, whereby data at sounder control points is interpolated to ionospheric reflection points for communication paths of interest. The results from the interpolation are found to be at least 20-30% more accurate than updating at any one of the nearby sounder control points. The updating procedure applies under day and night conditions, and also works well in a forecasting mode (not real-time), where it is found to work better in this case than a statistical trend line approach for daytime forecasting.

  10. Intercomparison of daytime stratospheric NO2 satellite retrievals and model simulations

    NARCIS (Netherlands)

    Belmonte Rivas, M.; Veefkind, J.P.; Boersma, F.; Levelt, P.; Eskes, H.; Gille, J.

    2014-01-01

    This paper evaluates the agreement between stratospheric NO2 retrievals from infrared limb sounders (Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and High Resolution Dynamics Limb Sounder (HIRDLS)) and solar UV/VIS backscatter sensors (Ozone Monitoring Instrument (OMI), Scanning

  11. A New Synthetic Library of the Near-infrared Ca II Triplet Indices. I. Index Definition, Calibration, and Relations with Stellar Atmospheric Parameters

    Science.gov (United States)

    Du, W.; Luo, A. L.; Zhao, Y. H.

    2012-02-01

    Adopting the SPECTRUM package, which is a stellar spectral synthesis program, we have synthesized a comprehensive set of 2890 near-infrared (NIR) synthetic spectra with a resolution and wavelength sampling similar to the Sloan Digital Sky Survey (SDSS) and the forthcoming Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectra. During the synthesis, we applied the "New grids of ATLAS9 Model Atmosphere" to develop a grid of local thermodynamic equilibrium model atmospheres for effective temperatures (T eff) ranging from 3500 to 7500 K, for surface gravities (log g) from 0.5 to 5.0 dex, for metallicities ([Fe/H]) from -4.0 to 0.5 dex, and for solar ([α/Fe] = 0.0 dex) and non-solar ([α/Fe] = +0.4 dex) abundances. This synthetic stellar library is composed of 1350 solar scaled abundance (SSA) and 1530 non-solar scaled abundance (NSSA) spectra, grounding on which we have defined a new set of NIR Ca II triplet indices and an index CaT as the sum of the three. These defined indices were automatically measured on every spectrum of the synthetic stellar library and calibrated with the indices computed on the observational spectra from the INDO-U.S. stellar library. In order to check the effect of α-element enhancement on the so-defined Ca II indices, we compared indices measured on the SSA spectra with those on the NSSA ones at the same trine of stellar parameters (T eff, log g, [Fe/H]); luckily, little influences of α-element enhancement were found. Furthermore, comparisons of our synthetic indices with the observational ones from measurements on the INDO-U.S. stellar library, the SDSS-DR7 and SDSS-DR8 spectroscopic survey are presented, respectively, for dwarfs and giants in specific. For dwarfs, our synthetic indices could well reproduce the behaviors of the observational indices versus stellar parameters, which verifies the validity of our index definitions for dwarfs. For giants, the consistency between our synthetic indices and the observational

  12. A NEW SYNTHETIC LIBRARY OF THE NEAR-INFRARED Ca II TRIPLET INDICES. I. INDEX DEFINITION, CALIBRATION, AND RELATIONS WITH STELLAR ATMOSPHERIC PARAMETERS

    International Nuclear Information System (INIS)

    Adopting the SPECTRUM package, which is a stellar spectral synthesis program, we have synthesized a comprehensive set of 2890 near-infrared (NIR) synthetic spectra with a resolution and wavelength sampling similar to the Sloan Digital Sky Survey (SDSS) and the forthcoming Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectra. During the synthesis, we applied the 'New grids of ATLAS9 Model Atmosphere' to develop a grid of local thermodynamic equilibrium model atmospheres for effective temperatures (Teff) ranging from 3500 to 7500 K, for surface gravities (log g) from 0.5 to 5.0 dex, for metallicities ([Fe/H]) from –4.0 to 0.5 dex, and for solar ([α/Fe] = 0.0 dex) and non-solar ([α/Fe] = +0.4 dex) abundances. This synthetic stellar library is composed of 1350 solar scaled abundance (SSA) and 1530 non-solar scaled abundance (NSSA) spectra, grounding on which we have defined a new set of NIR Ca II triplet indices and an index CaT as the sum of the three. These defined indices were automatically measured on every spectrum of the synthetic stellar library and calibrated with the indices computed on the observational spectra from the INDO-U.S. stellar library. In order to check the effect of α-element enhancement on the so-defined Ca II indices, we compared indices measured on the SSA spectra with those on the NSSA ones at the same trine of stellar parameters (Teff, log g, [Fe/H]); luckily, little influences of α-element enhancement were found. Furthermore, comparisons of our synthetic indices with the observational ones from measurements on the INDO-U.S. stellar library, the SDSS-DR7 and SDSS-DR8 spectroscopic survey are presented, respectively, for dwarfs and giants in specific. For dwarfs, our synthetic indices could well reproduce the behaviors of the observational indices versus stellar parameters, which verifies the validity of our index definitions for dwarfs. For giants, the consistency between our synthetic indices and the observational

  13. Noise estimating and filtering of hyperspectral infrared radiance

    Science.gov (United States)

    Qu, Yanni; Goldberg, Mitchell D.

    2003-06-01

    Atmospheric InfraRed Sounder (AIRS) is a hyper-spectral infrared instrument on the EOS-Aqua satellite. Principal Component Analysis (PCA) of realistic simulations of AIRS radiances, which includes the effects of variable clouds and surface parameters, can be used to estimate and filter AIRS instrumental noise. The PCA uses noise scaled radiance, i.e. radiance divided by noise (R/N). Since the square root of the eigenvalues is equivalent to the standard deviation of the principal component score of the dependent ensemble, the square root of the eigenvalues in the R/N domain can be interpreted as a signal to the noise ratio for the new principal components (PC) or say "abstract channels". New PCs are arranged from the largest to the smallest eigenvalues. Once the R/N ratio is below unity, the signal has less contribution than noise for that PC and all the remaining PCs. This physical meaningful fact can be a criterion for radiance noise filtering. Using the linearity of PCA to the pure signal S plus ideal noise N in the R/N domain, PCA(N/N) becomes PCA(I). I is the identity matrix and hence eigenvalues of I are all equal. If reconstructing I, only k/m information can be recovered by k eigenvectors, where k = 1 .... m eigenvectors. Thus, it is easy to know how much noise merged into the reconstructed radiance and how many eigenvectors are needed for filtering noise when performing PCA in R/N domain. The number of eigenvectors to be used for noise estimating is around 60 in all sky conditions. 60 eigenvectors can filter over 97% of noise. Only 3% noise remains in the reconstructed data. Signal information can be recovered with accuracy in noise level. In addition, there is less than 5% error using PCA to estimate noise. Preliminary results from the real AIRS observation are discussed briefly.

  14. Ultra-Wideband Channel Sounder – Design, Construction and Selected Applications

    Directory of Open Access Journals (Sweden)

    R. Zetik

    2013-06-01

    Full Text Available The paper describes construction, design, and application of a real-time ultra-wideband channel sounder. Its specific architecture allows measurements of time-variant radio propagation channels in different frequency bands. The sounder’s stimulation signal is the maximum length binary sequence. Synchronous multi-channel operation is supported by its excellent timing stability and by its low power consumption of miniature sized low temperature co-fired ceramics modules that comprise custom integrated SiGe circuits. This is a prerequisite to build a multiple-input-multiple-output sounder which is suitable for sounding even in distributed scenarios such as sensor networks. Selected application examples demonstrated the performance and possibilities of the sounder.

  15. FMCW channel sounder with digital processing for measuring the coherence of wideband HF radio links

    Science.gov (United States)

    Salous, S.

    1986-08-01

    Multipath propagation, and in particular, the interference between the ordinary and the extraordinary waves, places a fundamental constraint on the performance of wideband HF skywave radio links. Furthermore, the dispersive nature of ionospheric propagation causes phase nonlinearity and hence distortion of narrow pulses. In this paper, an FMCW wideband sounder built for the purposes of characterizing the channel is described. Spectral analysis of the audio output of the sounder via the FFT algorithm is shown to permit measurement of thef amplitude/frequency function, the polarization bandwidth, the fade rate, the fade depth and the distortion of a narrow pulse, all for a desired isolated ionospheric propagation mode. The sounder was used to collect data over an oblique path in the UK. The results of applying the FFT processing technique to the experimental data are presented.

  16. CIRS-lite as a lightweight atmospheric sounder for Earth trace-gas science Project

    Data.gov (United States)

    National Aeronautics and Space Administration — CIRS-lite is a lightweight  version of the CIRS 43-kg Fourier transform spectrometer (FTS) currently returning data from Saturn.  CIRS-lite is of interest...

  17. Implementing earth observation and advanced satellite based atmospheric sounders for water resource and climate modelling

    DEFF Research Database (Denmark)

    Boegh, E.; Dellwik, Ebba; Hahmann, Andrea N.;

    effective land surface representation in water resource modeling” (2009- 2012). The purpose of the new research project is to develop remote sensing based model tools capable of quantifying the relative effects of site-specific land use change and climate variability at different spatial scales. For this...

  18. ULF wave occurrence statistics in a high-latitude HF Doppler sounder

    OpenAIRE

    Wright, D. M.; Yeoman, T.K.; T. B. Jones

    1999-01-01

    Ultra low frequency (ULF) wave activity in the high-latitude ionosphere has been observed by a high frequency (HF) Doppler sounder located at Tromsø, Norway (69.7°N, 19.2°E geographic coordinates). A statistical study of the occurrence of these waves has been undertaken from data collected between 1979 and 1984. The diurnal, seasonal, solar cycle and geomagnetic activity variations in occurrence have been investigated. The findings demonstrate that the ability of the sounder to detect ULF wav...

  19. WESTZOO Data (Wideband Echo Sounder Technology for Zooplankton Classification (WESTZOO))

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a three-year collaborative research work led by Prof. Egil Ona Institute of Marine Research (IMR), Bergen, Norway involving scientists from different...

  20. Spread F at low latitudes as observed by ionospheric Doppler sounders

    Czech Academy of Sciences Publication Activity Database

    Chum, Jaroslav; Laštovička, Jan; Cabrera, M. A.; Liu, J.-Y.; Baše, Jiří; Bonomi, F. A. M.; Burešová, Dalia; Fišer, Jiří; Hruška, František; Ezquer, R. G.

    Bahir Dar: Bahir Dar University, 2015. s. 90. [International Symposium on Equatorial Aeronomy (ISEA) /14./. 19.10.2015-23.10.2015, Bahir Dar] Institutional support: RVO:68378289 Keywords : spread F * multi-point Doppler sounders * ionosphere * magnetosphere Subject RIV: DG - Athmosphere Sciences, Meteorology

  1. A technique for recording HF (High Frequency) oblique-incidence-sounder data

    Science.gov (United States)

    Daehler, Mark

    1988-08-01

    This report details the equipment, formats, and procedures developed for recording and displaying HF propagation data produced by the AN/TRQ-35 RCS-4B oblique-incidence sounder receiver. The information is being published in this form because of numerous requests regarding a means for using the large volume of sounder data accumulated by NRL in the course of its ionospheric effects studies. These techniques may ultimately be incorporated in a proposed worldwide database of ionospheric data. The AN/TRQ-35 sounder equipment is available to all branches of the DOD and is widely used for near-real-time HF frequency management. The data it produces, if properly recorded and stored, can also be used for numerous other purposes related to studies of ionospheric structure and HF skywave communications. These include studies of the electron density versus height profile of the ionosphere; of forecasts of propagation conditions relevant to HF communications; of the geographical and temporal limitations of sounder data application; and of the effectiveness of frequency management techniques. Permanent records of ionospheric propagation have also proved valuable in evaluating tests of HF devices which are dependent on ionospheric propagation, such as communications transmitters and receivers, or direction finding equipment.

  2. Estimation of dielectric constant of lunar material by HF sounder observation

    Science.gov (United States)

    Kobayashi, T.; Ono, T.

    Space borne radio sounding observation has been one of indispensable items in planetary missions An HF sounder Lunar Radar Sounder LRS will be onboard SELENE a lunar exploration program of Japan in 2007 Its primary objective is subsurface geologic structure of the Moon Especially mare regions are of strong interest of investigators because of its relatively smooth surface it is thought that smooth surface allows us to see subsurface feature with less difficulty However even if a clear subsurface image is obtained the data does not provide us with quantitative information unless the dielectric constant of the lunar subsurface material We propose a technique to estimate the dielectric constant of lunar material that utilizes HF sounder data of closely located multiple orbits The technique is applied to SAR images that are produced from HF sounder data and stands on the fact that the apparent position of subsurface object varies as a function of the dielectric constant of subsurface material Assuming a uniform subsurface material the displacement of images of a subsurface target should be consistent with that of observation orbits if the correct dielectric constant of the subsurface material is assumed A numerical model on geometrical optics estimates that the proposed technique requires a synthetic aperture larger than about 50km provided that the orbit altitude is 100km subsurface target depth is a few km and that the observation frequency is 5MHz with 2MHz bandwidth Some laboratory experiments were conducted to demonstrate validity of the

  3. Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system

    Science.gov (United States)

    Li, Juan; Liu, Guiqing

    2016-07-01

    FengYun-3C (FY-3C) is an operational polar-orbiting satellite carrying the new-generation microwave sounding instruments in China. This paper describes the assimilation of the FY-3C Microwave Temperature Sounder-2 (MWTS-2) radiances in the Global and Regional Assimilation and PrEdiction System (GRAPES) of China Meteorological Administration. A quality control (QC) procedure for the assimilation of MWTS-2 radiance is proposed. Extensive monitoring before assimilation shows that MWTS-2 observations exhibit a clear striping pattern. A technique combining principal component analysis (PCA) and ensemble empirical mode decomposition (EEMD) is applied to the observations to remove the striping noise. Cloudy field-of-views (FOVs) are identified by applying the Visible and InfrarRed Radiometer (VIRR) cloud fraction threshold of 76 %. Other QC steps are conducted in the follow order: (i) coastal FOVs are removed, (ii) eight outmost FOVs are not used, (iii) channel 5 data over sea ice and land are not used, (iv) channel 6 observations are not used if the terrain altitudes are higher than 500 m, and (v) outliers with large differences between observations and model simulations are removed. Approximately 83, 75, 40, and 40 % of the observations are removed by the proposed QC for channels 5-8, respectively. After QC, the global biases and standard deviations are reduced significantly. The assimilation of the MWTS-2 radiances shows a positive impact when the control experiment assimilates only conventional observations. The experiments also show that the analysis and forecast errors are slightly reduced when the striping noise is removed from the observations. The quality control scheme of extracting the striping noise may contribute to the analysis and forecast accuracy. The impact of MWTS-2 is neutral when the conventional data and other satellite data are all assimilated.

  4. GHRSST Level 2P Global Skin Sea Surface Temperature from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-B satellite (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A global 1 km Group for High Resolution Sea Surface Temperature (GHRSST) Level 2P dataset based on multi-channel sea surface temperature (SST) retrievals generated...

  5. GHRSST Level 2P Global Skin Sea Surface Temperature from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A satellite (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A global 1 km Group for High Resolution Sea Surface Temperature (GHRSST) Level 2P dataset based on multi-channel sea surface temperature (SST) retrievals generated...

  6. Using airborne HIAPER Pole-to-Pole Observations (HIPPO) to evaluate model and remote sensing estimates of atmospheric carbon dioxide

    Science.gov (United States)

    Frankenberg, Christian; Kulawik, Susan S.; Wofsy, Steven C.; Chevallier, Frédéric; Daube, Bruce; Kort, Eric A.; O'Dell, Christopher; Olsen, Edward T.; Osterman, Gregory

    2016-06-01

    In recent years, space-borne observations of atmospheric carbon dioxide (CO2) have been increasingly used in global carbon-cycle studies. In order to obtain added value from space-borne measurements, they have to suffice stringent accuracy and precision requirements, with the latter being less crucial as it can be reduced by just enhanced sample size. Validation of CO2 column-averaged dry air mole fractions (XCO2) heavily relies on measurements of the Total Carbon Column Observing Network (TCCON). Owing to the sparseness of the network and the requirements imposed on space-based measurements, independent additional validation is highly valuable. Here, we use observations from the High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) flights from 01/2009 through 09/2011 to validate CO2 measurements from satellites (Greenhouse Gases Observing Satellite - GOSAT, Thermal Emission Sounder - TES, Atmospheric Infrared Sounder - AIRS) and atmospheric inversion models (CarbonTracker CT2013B, Monitoring Atmospheric Composition and Climate (MACC) v13r1). We find that the atmospheric models capture the XCO2 variability observed in HIPPO flights very well, with correlation coefficients (r2) of 0.93 and 0.95 for CT2013B and MACC, respectively. Some larger discrepancies can be observed in profile comparisons at higher latitudes, in particular at 300 hPa during the peaks of either carbon uptake or release. These deviations can be up to 4 ppm and hint at misrepresentation of vertical transport. Comparisons with the GOSAT satellite are of comparable quality, with an r2 of 0.85, a mean bias μ of -0.06 ppm, and a standard deviation σ of 0.45 ppm. TES exhibits an r2 of 0.75, μ of 0.34 ppm, and σ of 1.13 ppm. For AIRS, we find an r2 of 0.37, μ of 1.11 ppm, and σ of 1.46 ppm, with latitude-dependent biases. For these comparisons at least 6, 20, and 50 atmospheric soundings have been averaged for GOSAT, TES, and AIRS

  7. Global distributions, time series and error characterization of atmospheric ammonia (NH3) from IASI satellite observations

    Science.gov (United States)

    Van Damme, M.; Clarisse, L.; Heald, C. L.; Hurtmans, D.; Ngadi, Y.; Clerbaux, C.; Dolman, A. J.; Erisman, J. W.; Coheur, P. F.

    2014-03-01

    Ammonia (NH3) emissions in the atmosphere have increased substantially over the past decades, largely because of intensive livestock production and use of fertilizers. As a short-lived species, NH3 is highly variable in the atmosphere and its concentration is generally small, except near local sources. While ground-based measurements are possible, they are challenging and sparse. Advanced infrared sounders in orbit have recently demonstrated their capability to measure NH3, offering a new tool to refine global and regional budgets. In this paper we describe an improved retrieval scheme of NH3 total columns from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI). It exploits the hyperspectral character of this instrument by using an extended spectral range (800-1200 cm-1) where NH3 is optically active. This scheme consists of the calculation of a dimensionless spectral index from the IASI level1C radiances, which is subsequently converted to a total NH3 column using look-up tables built from forward radiative transfer model simulations. We show how to retrieve the NH3 total columns from IASI quasi-globally and twice daily above both land and sea without large computational resources and with an improved detection limit. The retrieval also includes error characterization of the retrieved columns. Five years of IASI measurements (1 November 2007 to 31 October 2012) have been processed to acquire the first global and multiple-year data set of NH3 total columns, which are evaluated and compared to similar products from other retrieval methods. Spatial distributions from the five years data set are provided and analyzed at global and regional scales. In particular, we show the ability of this method to identify smaller emission sources than those previously reported, as well as transport patterns over the ocean. The five-year time series is further examined in terms of seasonality and interannual variability (in particular as a function of fire

  8. Laser Sounder for Global Measurement of CO2 Concentrations in the Troposphere from Space: Update

    Science.gov (United States)

    Abshire, J. B.; Riris, H.; Kawa, S. R.; Sun, X.; Krainak, M. A.; Mao, J.; Jian, P.; Collatz, G. J.; Stephen, M.

    2006-12-01

    We report progress in developing a laser technique for the remote measurement of the tropospheric CO2 concentrations from orbit. Our initial goal is to demonstrate a lidar technique and instrument technology that will permit measurements of the CO2 column abundance in the lower troposphere from aircraft. Our final goal is to develop a practical space instrument and mission approach for active CO2 measurements at the 1 ppmv level. This would allow continuous measurements of CO2 mixing ratio, both day and night, over land and ocean surfaces, under realistic atmospheric scattering conditions. Measuring the CO2 mixing ratio in the troposphere from space is quite challenging. High signal-to-noise ratios and measurement stabilities are needed for accurate mixing ratio estimates. Our laser sounder approach has some fundamental advantages over passive sensors which use sunlight. It always uses a common nadir/zenith measurement path and the narrow laser divergence angles produce small laser footprints. The laser source allows it to measure in sunlight and darkness over different surfaces giving full global coverage. It can measure continuously over the ocean, to cloud tops and through broken clouds. The lasers are pulsed and potential measurement errors from aerosol scattering can be greatly reduced by using time gating in the receiver. Our approach uses a dual channel laser altimeter/spectrometer, which continuously measures at nadir from a near polar circular orbit. It uses several tunable fiber lasers for simultaneous measurement of the absorption from CO2 and O2, and aerosol backscatter in the same path. It directs the narrow co-aligned laser beams from the instrument's lasers toward nadir, and measures the energy of the laser echoes reflected from land and water surfaces During the measurement its lasers are tuned on- and off- a selected CO2 line near 1572 nm and a selected O2 line near 768 nm in the Oxygen A band at kHz rates. The receiver uses a 1-m diameter

  9. A multi-wavelength classification method for polar stratospheric cloud types using infrared limb spectra

    Science.gov (United States)

    Spang, Reinhold; Hoffmann, Lars; Höpfner, Michael; Griessbach, Sabine; Müller, Rolf; Pitts, Michael C.; Orr, Andrew M. W.; Riese, Martin

    2016-08-01

    compared to the real fraction of ice within the PSC area in the polar vortex. The entire MIPAS measurement period was processed with the new classification approach. Examples like the detection of the Antarctic NAT belt during early winter, and its possible link to mountain wave events over the Antarctic Peninsula, which are observed by the Atmospheric Infrared Sounder (AIRS) instrument, highlight the importance of a climatology of 9 Southern Hemisphere and 10 Northern Hemisphere winters in total. The new dataset is valuable both for detailed process studies, and for comparisons with and improvements of the PSC parameterizations used in chemistry transport and climate models.

  10. Distribution functions and statistical parameters that may be used to characterize limb sounders gravity wave climatologies in the stratosphere

    Science.gov (United States)

    Alexander, P.; Luna, D.; de la Torre, A.; Schmidt, T.

    2015-08-01

    The number of gravity wave (GW) activity climatologies in the stratosphere started to increase more than 10 years ago since the appearance of large amounts of limb and nadir satellite sounders data. There have been very few discussions regarding the adequate statistical description of GW activity in terms of a distribution function and its parameters. We put forward the question whether a general statistical functional representation adaptable to the characteristics of GW activity in diverse geographic regions and seasons exists. Here we approach this issue for two different types of limb sounders and in particular we try to find out which parameters may represent at best the climatological features. We study results for a region close to the Patagonian Andes and their prolongation in the Antarctic Peninsula, which is well-known for the generation by topography of intense stratospheric GW, specially during winter and spring. Global Positioning System (GPS) radio occultation (RO) records presently provide over 2000 profiles per day. We used 5 years of COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) mission GPS RO data, which supplied almost 150,000 retrievals for our study. Three different distribution functions have been approached to describe the GW activity climatologies: gaussian, log-normal and gamma. The latter function has not been used in previous work. It has been shown here that it is a competitive option to the log-normal distribution. In addition, its use allows not only to quantify the GW activity level of each climatology in the stratosphere, but also to find out the number of significant modes that essentially determine it. Alternative parameters to the mean like the median may be used to characterize the climatologies. The use of the median may exhibit advantages in cases where the presence of spurious large GW activity measurements are suspected in GPS RO data. The mean is equally suitable to establish GW activity

  11. Atmospheric transport, clouds and the Arctic longwave radiation paradox

    Science.gov (United States)

    Sedlar, Joseph

    2016-04-01

    Clouds interact with radiation, causing variations in the amount of electromagnetic energy reaching the Earth's surface, or escaping the climate system to space. While globally clouds lead to an overall cooling radiative effect at the surface, over the Arctic, where annual cloud fractions are high, the surface cloud radiative effect generally results in a warming. The additional energy input from absorption and re-emission of longwave radiation by the clouds to the surface can have a profound effect on the sea ice state. Anomalous atmospheric transport of heat and moisture into the Arctic, promoting cloud formation and enhancing surface longwave radiation anomalies, has been identified as an important mechanism in preconditioning Arctic sea ice for melt. Longwave radiation is emitted equally in all directions, and changes in the atmospheric infrared emission temperature and emissivity associated with advection of heat and moisture over the Arctic should correspondingly lead to an anomalous signal in longwave radiation at the top of the atmosphere (TOA). To examine the role of atmospheric heat and moisture transport into the Arctic on TOA longwave radiation, infrared satellite sounder observations from AIRS during 2003-2014 are analyzed for summer (JJAS). Thermodynamic metrics are developed to identify months characterized by a high frequency of warm and moist advection into the Arctic, and segregate the 2003-14 time period into climatological and anomalously warm, moist summer months. We find that anomalously warm, moist months result in a significant TOA longwave radiative cooling, which is opposite the forcing signal that the surface experiences during these months. At the timescale of the advective events, 3-10 days, the TOA cooling can be as large as the net surface energy budget during summer. When averaged on the monthly time scale, and over the full Arctic basin (poleward of 75°N), summer months experiencing frequent warm, moist advection events are

  12. Carbon monoxide mixing ratios over Oklahoma between 2002 and 2009 retrieved from Atmospheric Emitted Radiance Interferometer spectra

    Directory of Open Access Journals (Sweden)

    L. Yurganov

    2010-10-01

    Full Text Available CO mixing ratios for the lowermost 2-km atmospheric layer were retrieved from downwelling infrared (IR radiance spectra of the clear sky measured between 2002 and 2009 by a zenith-viewing Atmospheric Emitted Radiance Interferometer (AERI deployed at the Southern Great Plains (SGP observatory of the Atmospheric Radiation Measurements (ARM Program near Lamont, Oklahoma. A version of a published earlier retrieval algorithm was improved and validated. Archived temperature and water vapor profiles retrieved from the same AERI spectra through automated ARM processing were used as input data for the CO retrievals. We found the archived water vapor profiles required additional constraint using SGP Microwave Radiometer retrievals of total precipitable water vapor. A correction for scattered solar light was developed as well. The retrieved CO was validated using simultaneous independently measured CO profiles from an aircraft. These tropospheric CO profiles were measured from the surface to altitudes of 4572 m a.s.l. once or twice a week between March 2006 and December 2008. The aircraft measurements were supplemented with ground-based CO measurements using a non-dispersive infrared gas correlation instrument at the SGP and retrievals from the Atmospheric IR Sounder (AIRS above 5 km to create full tropospheric CO profiles. Comparison of the profiles convolved with averaging kernels to the AERI CO retrievals found a squared correlation coefficient of 0.57, a standard deviation of ±11.7 ppbv, a bias of -16 ppbv, and a slope of 0.92. Averaged seasonal and diurnal cycles measured by the AERI are compared with those measured continuously in situ at the SGP in the boundary layer. Monthly mean CO values measured by the AERI between 2002 and 2009 are compared with those measured by the AIRS over North America, the Northern Hemisphere mid-latitudes, and over the tropics.

  13. Infrared radiative transfer in atmospheres of Earth-like planets around F, G, K, and M stars. II. Thermal emission spectra influenced by clouds

    Science.gov (United States)

    Vasquez, M.; Schreier, F.; Gimeno García, S.; Kitzmann, D.; Patzer, B.; Rauer, H.; Trautmann, T.

    2013-09-01

    Context. Clouds play an important role in the radiative transfer of planetary atmospheres because of the influence they have on the different molecular signatures through scattering and absorption processes. Furthermore, they are important modulators of the radiative energy budget affecting surface and atmospheric temperatures. Aims: We present a detailed study of the thermal emission of cloud-covered planets orbiting F-, G-, K-, and M-type stars. These Earth-like planets include planets with the same gravity and total irradiation as Earth, but can differ significantly in the upper atmosphere. The impact of single-layered clouds is analyzed to determine what information on the atmosphere may be lost or gained. The planetary spectra are studied at different instrument resolutions and compared to previously calculated low-resolution spectra. Methods: A line-by-line molecular absorption model coupled with a multiple scattering radiative transfer solver was used to calculate the spectra of cloud-covered planets. The atmospheric profiles used in the radiation calculations were obtained with a radiative-convective climate model combined with a parametric cloud description. Results: In the high-resolution flux spectra, clouds changed the intensities and shapes of the bands of CO2, N2O, H2O, CH4, and O3. Some of these bands turned out to be highly reduced by the presence of clouds, which causes difficulties for their detection. The most affected spectral bands resulted for the planet orbiting the F-type star. Clouds could lead to false negative interpretations for the different molecular species investigated. However, at low resolution, clouds were found to be crucial for detecting some of the molecular bands that could not be distinguished in the cloud-free atmospheres. The CO2 bands were found to be less affected by clouds. Radiation sources were visualized with weighting functions at high resolution. Conclusions: Knowledge of the atmospheric temperature profile is

  14. Adaptive Protocols to Improve TCP/IP Performance in an LMDS Network using a Broadband Channel Sounder

    OpenAIRE

    Eshler, Todd Jacob

    2002-01-01

    Virginia Tech researchers have developed a broadband channel sounder that can measure channel quality while a wireless network is in operation. Channel measurements from the broadband sounder hold the promise of improving TCP/IP performance by trigging configuration changes in an adaptive data link layer protocol. We present an adaptive data link layer protocol that can use different levels of forward error correction (FEC) codes and link layer automatic retransmission request ...

  15. ULF wave occurrence statistics in a high-latitude HF Doppler sounder

    Science.gov (United States)

    Wright, D. M.; Yeoman, T. K.; Jones, T. B.

    1999-06-01

    Ultra low frequency (ULF) wave activity in the high-latitude ionosphere has been observed by a high frequency (HF) Doppler sounder located at Tromsø, Norway (69.7°N, 19.2°E geographic coordinates). A statistical study of the occurrence of these waves has been undertaken from data collected between 1979 and 1984. The diurnal, seasonal, solar cycle and geomagnetic activity variations in occurrence have been investigated. The findings demonstrate that the ability of the sounder to detect ULF wave signatures maximises at the equinoxes and that there is a peak in occurrence in the morning sector. The occurrence rate is fairly insensitive to changes associated with the solar cycle but increases with the level of geomagnetic activity. As a result, it has been possible to characterise the way in which prevailing ionospheric and magnetospheric conditions affect such observations of ULF waves.

  16. Space Plasma Slab Studies using a new 3D Embedded Reconfigurable MPSoC Sounder

    Science.gov (United States)

    Dekoulis, George

    2016-07-01

    This paper presents recent ionospheric slab thickness measurements using a new mobile digital sounder system. The datasets obtained have been compared to the results of existing sounders in operation. The data validity has been verified. The slab thickness data allow constant monitoring of the lower ionosphere revealing the dynamic trends of the physical processes being involved. The prototype offers a tremendous amount of hardware processing power and a previously unseen response time in servicing the input and output data interfaces. This has been enabled by incorporating the latest three-dimensional Ultrascale+ technologies available commercially from the reconfigurable Field Programmable Gate Array (FPGA) computing industry. Furthermore, a previously developed Network-on-Chip (NoC) design methodology has been incorporated for connecting and controlling the application driven multiprocessor network. The system determines electron distributions, aggregate electromagnetic field gradients and plasma current density.

  17. PREMIER: a proposed mission to observe processes controlling atmospheric composition in the height range most important to climate

    Science.gov (United States)

    Kerridge, Brian; Orphal, Johannes; van Weele, Michiel; Murtagh, Donal; McConnell, Jack; Hegglin, Michaela; Peuch, Vincent-Henri; Reise, Martin

    2010-05-01

    The PREMIER (PRocess Exploration through Measurements of Infrared and millimetre-wave Emitted Radiation) mission is one of three candidates for ESA's 7th Earth Explorer Core Mission (due for launch in 2016) that have been approved for Phase A study. The mission proposes to make detailed measurements in the mid/upper troposphere and lower stratosphere in order to quantify processes controlling atmospheric global composition in this height range of particular importance to climate. PREMIER would consist of an infrared limb imaging spectrometer which would observe 3D fields of trace gases, alongside a millimetre-wave limb sounder which would enable observations in the presence of most cirrus clouds, and also provide complementary trace gases. In addition, co-located data from EPS-MetOp would be combined with that from PREMIER, to extend the scientific impact of PREMIER down into the lower troposphere, to explore links to surface emissions and pollution. In this presentation, simulations of its capabilities will be described together with some preliminary results from airborne precursors

  18. EOS Microwave Limb Sounder observations of the Antarctic polar vortex breakup in 2004

    OpenAIRE

    Manney, G. L.; M. L. Santee; N. J. Livesey; Froidevaux, L.; W. G. Read; Pumphrey, H. C.; Waters, J.W.; Pawson, S.

    2005-01-01

    New observations from the Microwave Limb Sounder (MLS) on NASA's Aura satellite give a detailed picture of the spring Antarctic polar vortex breakup throughout the stratosphere, with the first daily global HCl profiles providing an unprecedentedly clear view of transport in the lower stratosphere. Poleward transport at progressively lower levels, filamentation, and mixing are detailed in MLS HCl, N2O, H2O, and O3 as the 2004 Antarctic vortex broke up from the top down in early October through...

  19. Solar and Infrared Radiation Station (SIRS) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Stoffel, T

    2005-07-01

    The Solar Infrared Radiation Station (SIRS) provides continuous measurements of broadband shortwave (solar) and longwave (atmospheric or infrared) irradiances for downwelling and upwelling components. The following six irradiance measurements are collected from a network of stations to help determine the total radiative flux exchange within the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Climate Research Facility: • Direct normal shortwave (solar beam) • Diffuse horizontal shortwave (sky) • Global horizontal shortwave (total hemispheric) • Upwelling shortwave (reflected) • Downwelling longwave (atmospheric infrared) • Upwelling longwave (surface infrared)

  20. Wide Field Collimator 2 (WFC2) for GOES Imager and Sounder

    Science.gov (United States)

    Etemad, Shahriar; Bremer, James C.; Zukowski, Barbara J.; Pasquale, Bert A.; zukowski, Tmitri J.; Prince, Robert E.; O'Neill, Patrick A.; Ross, Robert W.

    2004-01-01

    Two of the GOES instruments, the Imager and the Sounder, perform scans of the Earth to provide a full disc picture of the Earth. To verify the entire scan process, an image of a target that covers an 18 deg. circular field-of-view is collimated and projected into the field of regard of each instrument. The Wide Field Collimator 2 (WFC2) has many advantages over its predecessor, WFC1, including lower thermal dissipation higher fir field MTF, smaller package, and a more intuitive (faster) focusing process. The illumination source is an LED array that emits in a narrow spectral band centered at 689 nm, within the visible spectral bands of the Imager and Sounder. The illumination level can be continuously adjusted electronically. Lower thermal dissipation eliminates the need for forced convection cooling and minimizes time to reach thermal stability. The lens system has been optimized for the illumination source spectral output and athernalized to remain in focus during bulk temperature changes within the laboratory environment. The MTF of the lens is higher than that of the WFC1 at the edge of FOV. The target is focused in three orthogonal motions, controlled by an ergonomic system that saves substantial time and produces a sharper focus. Key words: Collimator, GOES, Imager, Sounder, Projector

  1. A new multibeam echo sounder/sonar for fishery research applications

    Science.gov (United States)

    Andersen, Lars Nonboe; Berg, Sverre; Stenersen, Erik; Gammelsaeter, Ole Bernt; Lunde, Even Borte

    2003-10-01

    Fisheries scientists have for many years been requesting a calibrated multibeam echo sounder/sonar specially designed for fishery research applications. Simrad AS has, in cooperation with IFREMER, France, agreed on specifications for a multibeam echo sounder and with IMR, Norway for a multibeam sonar, and contracts were signed for development of such systems in January 2003. The systems have 800 transmitting and receiving channels with similar hardware, but different software, and are characterized by narrow beams, low-sidelobe levels, and operate in the frequency range 70-120 kHz. The echo sounder is designed for high operating flexibility, with 1 to 47 beams of approximately 2°, covering a maximum sector of 60°. In addition, normal split beam mode on 70 and 120 kHz with 7° beams for comparison with standard system is available. The sonar will be mounted on a drop keel, looking horizontally, covering a horizontal sector of +/-30°, and a vertical sector of 45°. Total number of beams is 500, 25 beams horizontally with a resolution of ~3°, and 20 beams vertically with a resolution of ~4°. Both systems are designed for accurate fish-stock assessment and fish-behavior studies.

  2. IIP Tropospheric Infrared Mapping Spectrometers (TIMS) demonstration of CO retrieval, including multi-layer, from atmospheric data acquired simultaneously in the solar reflective region near 2.3 um and the thermal emissive region near 4.7 um

    Science.gov (United States)

    Mergenthaler, J. L.; Kumer, J.; Roche, A. E.; Rairden, R. L.; Blatherwick, R.; Hawat, T.; Desouza-Machado, S.; Hannon, S.; Chatfield, R. B.

    2008-12-01

    The NASA Earth Science Technology Office (ESTO) Instrument Incubator Program (IIP) Tropospheric Infrared Mapping Spectrometers (TIMS) have been developed to demonstrate measurement capability, when deployed in space, for multi-layer retrieval of CO from spectral measurements acquired in the solar reflective (SR) region ~ 4281 to 4301 cm-1 and in the thermal InfraRed (TIR) region ~ 2110 to 2165 cm-1. We describe joint deployment at Denver University (DU) with co-investigators there of the TIMS, and of the DU colleagues FTS, to acquire simultaneous measurements of atmospheric spectra in the SR and the TIR. The FTS provided validation radiance data for the TIMS. The TIMS retrievals of CO, H2O and CH4 agreed well with validation vs these as retrieved from the DU data, AIRS retrieval, standard models and ECMWF. The TIMS CO retrievals included column retrieved from the just the SR data, column retrieved from just the TIR data, and a simple two-layer retrieval from the combined data sets. The data were acquired in an operational mode that mimicked the operations in a conceptual application that would provide footprints, coverage, refresh time as in the Decadal Survey GEO-CAPE mission statement. Very encouraging CO precisions were achieved, e.g., the TIMS CO column retrieval from the SR data demonstrated better than the 10% precision requirement as listed on slide 32 of the GEO-CAPE Reference document http://geo- cape.larc.nasa.gov/docs/GEOMAC_FinalReport_no_costs.ppt

  3. Infrared Measurements of Atmospheric Ethane (C2H6) From Aircraft and Ground-Based Solar Absorption Spectra in the 3000/ cm Region

    Science.gov (United States)

    Coffey, M. T.; Mankin, W. G.; Goldman, A.; Rinsland, C. P.; Harvey, G. A.; Devi, V. Malathy; Stokes, G. M.

    1985-01-01

    A number or prominent Q-branches or the upsilon(sub 7) band or C2H6 have been identified near 3000/ cm in aircraft and ground-based infrared solar absorption spectra. The aircraft spectra provide the column amount above 12 km at various altitudes. The column amount is strongly correlated with tropopause height and can be described by a constant mixing ratio of 0.46 ppbv in the upper troposphere and a mixing ratio scale height of 3.9 km above the tropopause. The, ground-based spectra yield a column of 9.0 x 10(exp 15) molecules/sq cm above 2.1 km; combining these results implies a tropospheric mixing ratio of approximately 0.63 ppbv.

  4. Precipitation in Madeira island and atmospheric rivers in the winter seasons

    Science.gov (United States)

    Couto, Flavio T.; Salgado, Rui; João Costa, Maria; Prior, Victor

    2016-04-01

    This study aims to analyse the distribution of the daily accumulated precipitation in the Madeira's highlands over a 10-year period, as well as the main characteristics associated with atmospheric rivers (ARs) affecting the island during 10 winter seasons, and their impact in the rainfall amounts recorded near the mountain crest in the south-eastern part of the island. The period between September 2002 and November 2012 is considered for the analysis. The ARs have been identified from the total precipitable water vapour field extracted from the Atmospheric Infrared Sounder (AIRS). The AIRS observations were downloaded for a domain covering large part of the North Atlantic Ocean. The precipitable water vapour field from the European Centre for Medium-range Weather Forecasts (ECMWF) analysis was also used aiming to support the AIRS data when there was no satellite information over the island. The daily accumulated precipitation at surface showed generally drier summers, while the highest accumulated precipitation are recorded mainly during the winter, although some significant events may occur also in autumn and spring seasons. The patterns of the precipitable water vapour field when ARs reach the island were investigated, and even if great part of the atmospheric rivers reaches the island in a dissipation stage, some rivers are heavy enough to reach the Madeira Island. In this situation, the water vapour transport could be observed in two main configurations and transporting significant water vapour amounts toward the Madeira from the tropical region. This study lead to conclude that the atmospheric rivers, when associated to high values of precipitable water vapour over the island can provide favourable conditions to the development of precipitation, sometimes associated with high amounts. However, it was also found that many cases of high to extreme accumulated precipitation at the surface were not associated to this kind of moisture transport.

  5. Retrieval of atmospheric CO2 from satellite near-infrared nadir spectra in the frame of ESA's climate change initiative

    Energy Technology Data Exchange (ETDEWEB)

    Reuter, Maximilian; Buchwitz, Michael; Schneising, Oliver; Heymann, Jens; Bovensmann, Heinrich; Burrows, John [Institute of Environmental Physics, University of Bremen (Germany)

    2011-07-01

    ESA's climate change initiative (CCI) aims at global satellite measurements of essential climate variables (ECV). One of these variables is X{sub CO{sub 2}} (the column-average dry-air mole fraction of atmospheric CO{sub 2}) which is retrieved from the satellite instruments SCIAMACHY aboard ENVISAT and TANSO aboard GOSAT. Results of the SCIAMACHY retrieval algorithms WFM-DOAS and BESD are the focus of the presentation. This includes a comparison against ground based FTS measurements, GOSAT retrievals, and model results.

  6. Thermal Infrared Imaging and Atmospheric Modeling of VHS J125601.92-125723.9 b: Evidence for Moderately Thick Clouds and Equilibrium Carbon Chemistry in a Hierarchical Triple System

    CERN Document Server

    Rich, Evan A; Wisniewski, John P; Hashimoto, Jun; Brandt, Timothy D; Carson, Joseph C; Kuzuhara, Masayuki; Uyama, Taichi

    2016-01-01

    We present and analyze Subaru/IRCS L' and M' images of the nearby M dwarf VHS J125601.92-125723.9 (VHS 1256), which was recently claimed to have a ~11 M_Jup companion (VHS 1256 b) at ~102 au separation. Our AO images partially resolve the central star into a binary, whose components are nearly equal in brightness and separated by 0.106" +/- 0.001". VHS 1256 b occupies nearly the same near-IR color-magnitude diagram position as HR 8799 bcde and has a comparable L' brightness. However, it has a substantially redder H - M' color, implying a relatively brighter M' flux density than for the HR 8799 planets and suggesting that non-equilibrium carbon chemistry may be less significant in VHS 1256 b. We successfully match the entire SED (optical through thermal infrared) for VHS 1256 b to atmospheric models assuming chemical equilibrium, models which failed to reproduce HR 8799 b at 5 microns. Our modeling favors slightly thick clouds in the companion's atmosphere, although perhaps not quite as thick as those favored ...

  7. Atmospheric parameters in a subtropical cloud regime transition derived by AIRS+MODIS - observed statistical variability compared to ERA-Interim

    Science.gov (United States)

    Schreier, M. M.; Kahn, B. H.; Sušelj, K.; Karlsson, J.; Ou, S. C.; Yue, Q.; Nasiri, S. L.

    2013-09-01

    Cloud occurrence, microphysical and optical properties and atmospheric profiles within a subtropical cloud regime transition in the northeastern Pacific Ocean are obtained from a synergistic combination of the Atmospheric Infrared Sounder (AIRS) and the MODerate resolution Imaging Spectroradiometer (MODIS). The observed cloud parameters and atmospheric thermodynamic profile retrievals are binned by cloud type and analyzed based on their probability density functions (PDFs). Comparison of the PDFs to data from the European Center for Medium Range Weather Forecasting Re-analysis (ERA-Interim) shows a strong difference in the occurrence of the different cloud types compared to clear sky. An increasing non-Gaussian behavior is observed in cloud optical thickness (τc), effective radius (re) and cloud top temperature (Tc) distributions from Stratocumulus to Trade Cumulus, while decreasing values of lower tropospheric stability are seen. However, variations in the mean, width and shape of the distributions are found. The AIRS potential temperature (θ) and water vapor (q) profiles in the presence of varying marine boundary layer (MBL) cloud types show overall similarities to the ERA-Interim in the mean profiles, but differences arise in the higher moments at some altitudes. The differences between the PDFs from AIRS+MODIS and ERA-Interim make it possible to pinpoint systematic errors in both systems and helps to understand joint PDFs of cloud properties and coincident thermodynamic profiles from satellite observations.

  8. Atmospheric parameters in a subtropical cloud regime transition derived by AIRS and MODIS: observed statistical variability compared to ERA-Interim

    Science.gov (United States)

    Schreier, M. M.; Kahn, B. H.; Sušelj, K.; Karlsson, J.; Ou, S. C.; Yue, Q.; Nasiri, S. L.

    2014-04-01

    Cloud occurrence, microphysical and optical properties, and atmospheric profiles within a subtropical cloud regime transition in the northeastern Pacific Ocean are obtained from a synergistic combination of the Atmospheric Infrared Sounder (AIRS) and the MODerate resolution Imaging Spectroradiometer (MODIS). The observed cloud parameters and atmospheric thermodynamic profile retrievals are binned by cloud type and analyzed based on their probability density functions (PDFs). Comparison of the PDFs to data from the European Centre for Medium Range Weather Forecasting reanalysis (ERA-Interim) shows a strong difference in the occurrence of the different cloud types compared to clear sky. An increasing non-Gaussian behavior is observed in cloud optical thickness (τc), effective radius (re) and cloud-top temperature (Tc) distributions from stratocumulus to trade cumulus, while decreasing values of lower-tropospheric stability are seen. However, variations in the mean, width and shape of the distributions are found. The AIRS potential temperature (θ) and water vapor (q) profiles in the presence of varying marine boundary layer (MBL) cloud types show overall similarities to the ERA-Interim in the mean profiles, but differences arise in the higher moments at some altitudes. The differences between the PDFs from AIRS+MODIS and ERA-Interim make it possible to pinpoint systematic errors in both systems and help to understand joint PDFs of cloud properties and coincident thermodynamic profiles from satellite observations.

  9. Atmospheric parameters in a subtropical cloud regime transition derived by AIRS+MODIS – observed statistical variability compared to ERA-Interim

    Directory of Open Access Journals (Sweden)

    M. M. Schreier

    2013-09-01

    Full Text Available Cloud occurrence, microphysical and optical properties and atmospheric profiles within a subtropical cloud regime transition in the northeastern Pacific Ocean are obtained from a synergistic combination of the Atmospheric Infrared Sounder (AIRS and the MODerate resolution Imaging Spectroradiometer (MODIS. The observed cloud parameters and atmospheric thermodynamic profile retrievals are binned by cloud type and analyzed based on their probability density functions (PDFs. Comparison of the PDFs to data from the European Center for Medium Range Weather Forecasting Re-analysis (ERA-Interim shows a strong difference in the occurrence of the different cloud types compared to clear sky. An increasing non-Gaussian behavior is observed in cloud optical thickness (τc, effective radius (re and cloud top temperature (Tc distributions from Stratocumulus to Trade Cumulus, while decreasing values of lower tropospheric stability are seen. However, variations in the mean, width and shape of the distributions are found. The AIRS potential temperature (θ and water vapor (q profiles in the presence of varying marine boundary layer (MBL cloud types show overall similarities to the ERA-Interim in the mean profiles, but differences arise in the higher moments at some altitudes. The differences between the PDFs from AIRS+MODIS and ERA-Interim make it possible to pinpoint systematic errors in both systems and helps to understand joint PDFs of cloud properties and coincident thermodynamic profiles from satellite observations.

  10. Ocean-Atmosphere Interaction Over Agulhas Extension Meanders

    Science.gov (United States)

    Liu, W. Timothy; Xie, Xiaosu; Niiler, Pearn P.

    2007-01-01

    ENW over warm and cool water set up by the dependence of turbulent mixing on stability; this relation exerts a positive feedback to the ENW-SST relation. The temperature sounding measured by the Atmospheric Infrared Sounder(AIRS) is consistent with the spatial coherence between the cloud-top temperature provided by the International Satellite Cloud Climatology Project (ISCCP) and SST. Thus ocean mesoscale SST anomalies associated with the persistent meanders may have a long-term effect well above the midlatitude atmospheric boundary layer, an observation not addressed in the past.

  11. Radiometric Bharacteristics of FY-3B Microwave Humidity and Temperature Sounder%FY-3B 微波湿温探测仪辐射测量特性

    Institute of Scientific and Technical Information of China (English)

    郭杨; 卢乃锰; 谷松岩; 何杰颖; 王振占

    2014-01-01

    The microwave humidity sounder (MWHS)is a five channel microwave radiometer in the range of 150-191 GHz onboard FY-3A and FY-3B.FY-3A and FY-3B are successfully launched in 2008 and 2010,re-spectively.The next generation of MWHS is a microwave humidity and temperature sounder.This sensor is developed to fly on the third satellite of new generation polar orbit meteorological satellite of China (FY-3C)is launched in September 2013. The microwave humidity and temperature sounder has 15 channels in the range of 89 - 191 GHz. Eight temperature sounding channels with central frequency of 118.75 GHz oxygen gas line and five hu-midity sounding channels with central frequency of 183.31 GHz water vapor line.Two window channels center at 89 GHz and 150 GHz.118 GHz channel is first used to detect atmosphere on current operational satellite.Channels in the oxygen band are at around 54 GHz used by AMSU-A (advanced microwave sounding unit-A)and ATMS (advanced technology microwave sounder).Channels in the next oxygen ab-sorption band are at around 118.75 GHz,which can well detect atmosphere temperature in the lower trop-osphere.The temperature sounding channels around 118.75 GHz detect the atmosphere temperature from 900 hPa to 25 hPa.The microwave humidity and temperature sounder adds two humidity sounding chan-nels compared with MWHS that can obtain fine vertical distribution structure of atmosphere humidity. In order to determine the radiometric performance and the on-orbit use of the microwave humidity and temperature sounder,an extensive test is performed before launch.The microwave humidity and tempera-ture sounder is placed in a thermal-vacuum chamber where the cold and earth targets are installed at fixed position.The instrument temperature is controlled at 5℃,15℃ and 25℃ which is expected in orbit.The temperature of earth target maintains from 95 K to 330 K and space target is controlled at 95 K.Tempera-tures of these whole targets are measured by PRT (platinum

  12. Validation of line and continuum spectroscopic parameters with measurements of atmospheric emitted spectral radiance from far to mid infrared wave number range

    International Nuclear Information System (INIS)

    The latest release of a high-resolution transmission molecular absorption database along with two improved models of water vapor continuum absorption are used to check their impact on the improvement of state-of-art radiative transfer. Radiative transfer performance has been assessed using high mountains atmospheric emitted spectral downwelling radiance observations in the 360-1200 cm-1 spectral regions. These high mountains observations are particularly suited to check the behavior and performance in the water vapor rotation band. In addition, they also have allowed us to gain insight into understanding the quality of recent new compilation of lines and related treatment for the ν2 CO2 band and the O3 band at 9.6μm. Comparisons are made between forward calculations of atmospheric transmission spectra and spectral radiances measured using two ground-based Fourier transform instruments. The results demonstrate that water vapor absorption largely benefits from the recent improvement in the related continuum (both self and foreign). In addition, ozone absorption is very accurately reproduced and, although to a less extent, this is also the case of CO2 absorption in the long wave ν2 band.

  13. A new synthetic library of the Near-Infrared CaII triplet indices. I.Index Definition, Calibration and Relations with stellar atmospheric parameters

    CERN Document Server

    Du, Wei; Zhao, Yong-Heng

    2011-01-01

    Adopting the SPECTRUM package, we have synthesized a set of 2,890 Near-InfraRed (NIR) synthetic spectra with a resolution and wavelength sampling similar to the SDSS and the forthcoming LAMOST spectra. During the synthesis, we have applied the `New grids of ATLAS9 Model Atmosphere' to provide a grid of local thermodynamic equilibrium (LTE) model atmospheres. This synthetic stellar library is composed of 1,350 solor scaled abundance (SSA) and 1,530 non-solar scaled abundance (NSSA) spectra, grounding on which we have defined a new set of NIR CaII triplet indices and an index CaT as the sum of the three. Then, these defined indices have been automatically measured on the synthetic spectra and calibrated with the indices computed on the observational spectra from the INDO-U.S. stellar library. In order to check the effect of alpha-element enhancement on the so-defined CaII indices, we have compared indices measured on the SSA spectra with those on the NSSA ones at the same terns of stellar parameters (Teff, log ...

  14. Laser Sounder for Global Measurement of CO2 Concentrations in the Troposphere from Space: Progress

    Science.gov (United States)

    Abshire, J. B.; Krainak, M.; Riris, H. J.; Sun, X.; Riris, H.; Andrews, A. E.; Collatz, J.

    2004-01-01

    We describe progress toward developing a laser-based technique for the remote measurement of the tropospheric CO2 concentrations from orbit. Our goal is to demonstrate a lidar technique and instrument technology that will permit measurements of the CO2 column abundance in the lower troposphere from aircraft at the few ppm level, with a capability of scaling to permit global CO2 measurements from orbit. Accurate measurements of the tropospheric CO2 mixing ratio from space are challenging due to the many potential error sources. These include possible interference from other trace gas species, the effects of temperature, clouds, aerosols & turbulence in the path, changes in surface reflectivity, and variability in dry air density caused by changes in atmospheric pressure, water vapor and topographic height. Some potential instrumental errors include frequency drifts in the transmitter, small transmission and sensitivity drifts in the instrument. High signal-to-noise ratios and measurement stability are needed for mixing ratio estimates at the few ppm level. We have been developing a laser sounder approach as a candidate for a future space mission. It utilizes multiple different laser transmitters to permit simultaneous measurement of CO2 and O2 extinction, and aerosol backscatter in the same measurement path. It directs the narrow co-aligned laser beams from the instrument's fiber lasers toward nadir, and measures the energy of the strong laser echoes reflected from the Earth's land and water surfaces. During the measurement its narrow linewidth lasers are rapidly tuned on- and off- selected CO2 line near 1572 nm and an O2 absorption line near 770 nm. The receiver measures the energies of the laser echoes from the surface and any clouds and aerosols in the path with photon counting detectors. Ratioing the on- to off-line echo pulse energies for each gas permits the column extinction and column densities of CO2 and O2 to be estimated simultaneously via the

  15. Is Arcturus a well-understood K giant? Test of model atmospheres and potential companion detection by near-infrared interferometry

    CERN Document Server

    Verhoelst, T; Perrin, G; Decin, L; Eriksson, K; Ridgway, S T; Schuller, P A; Traub, W A; Millan-Gabet, R; Lacasse, M G; Waelkens, C

    2005-01-01

    We present near-IR interferometric measurements of the K1.5 giant Arcturus (alpha Bootis), obtained at the IOTA interferometer with the FLUOR instrument, in four narrow filters with central wavelengths ranging from 2.03 to 2.39 micron. These observations were expected to allow us to quantify the wavelength dependence of the diameter of a typical K giant. They are compared to predictions from both plane-parallel and spherical model atmospheres. Unexpectedly, neither can explain the observed visibilities. We show how these data suggest the presence of a companion, in accordance with the Hipparcos data on this star, and discuss this solution with respect to Arcturus' single star status.

  16. Multi-decade Measurements of the Long-Term Trends of Atmospheric Species by High-Spectral-Resolution Infrared Solar Absorption Spectroscopy

    Science.gov (United States)

    Rinsland, Curtis P.; Chiou, Linda; Goldman, Aaron; Hannigan, James W.

    2010-01-01

    Solar absorption spectra were recorded for the first time in 5 years with the McMath Fourier transform spectrometer at the US National solar Observatory on Kitt Peak in southern Arizona, USA (31.91 N latitude, 111.61 W longitude, 2.09 km altitude). The solar absorption spectra cover 750-1300 and 1850-5000 cm(sup -1) and were recorded on 20 days during March-June 2009. The measurements mark the continuation of a long-term record of atmospheric chemical composition measurements that have been used to quantify seasonal cycles and long-term trends of both tropospheric and stratospheric species from observations that began i 1977. Fits to the measured spectra have been performed, and they indicate the spectra obtained since return to operational status are nearly free of channeling and the instrument line shape function is well reproduced taking into account the measurement parameters. We report updated time series measurements of total columns for six atmospheric species and their analysis for seasonal cycles and long-term trends. An sn example, the time series fit shows a decrease in the annual increase rate i Montreal-Protocol-regulated chlorofluorocarbon CCL2F2 from 1.51 plus or minus 0.38% yr(sup -1) at the beginning of the time span to -1.54 plus or minus 1.28 yr(sup -1) at the end of the time span, 1 sigma, and hence provides evidence for the impact of those regulations on the trend.

  17. The Level 2 research product algorithms for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES

    Directory of Open Access Journals (Sweden)

    P. Baron

    2011-06-01

    Full Text Available This paper describes the algorithms of the level-2 research (L2r processing chain developed for the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES. The chain has been developed in parallel to the operational chain for conducting researches on calibration and retrieval algorithms. L2r chain products are available to the scientific community. The objective of version 2 is the retrieval of the vertical distribution of trace gases in the altitude range of 18–90 km. An theoretical error analysis is conducted to estimate the retrieval feasibility of key parameters of the processing: line-of-sight elevation tangent altitudes (or angles, temperature and O3 profiles. The line-of-sight tangent altitudes are retrieved between 20 and 50 km from the strong ozone (O3 line at 625.371 GHz, with low correlation with the O3 volume-mixing ratio and temperature retrieved profiles. Neglecting the non-linearity of the radiometric gain in the calibration procedure is the main systematic error. It is large for the retrieved temperature (between 5–10 K. Therefore, atmospheric pressure can not be derived from the retrieved temperature, and, then, in the altitude range where the line-of-sight tangent altitudes are retrieved, the retrieved trace gases profiles are found to be better represented on pressure levels than on altitude levels. The error analysis for the retrieved HOCl profile demonstrates that best results for inverting weak lines can be obtained by using narrow spectral windows. Future versions of the L2r algorithms will improve the temperature/pressure retrievals and also provide information in the upper tropospheric/lower stratospheric region (e.g., water vapor, ice content, O3 and on stratospheric and mesospheric line-of-sight winds.

  18. Sounder-updated statistical model predictions of maximum usable frequency for HF sky wave predictions. Memorandum report

    Energy Technology Data Exchange (ETDEWEB)

    Reilly, M.H.; Daehler, M.

    1985-10-30

    Measured solar parameters, such as sunspot number or 10.7 cm flux, have traditionally been used as inputs to drive statistical-model predictions of maximum usable frequencies (MUFs) on HF radio sky wave paths of interest. Much greater accuracy can be obtained by using ionospheric sounder inputs to drive or update statistical-model predictions, and this is demonstrated here using oblique-incidence sounder data from the DoD Solid Shield exercises on May 12-14, 1981. From analysis of ionograms collected for several paths every fifteen minutes, it is found that deployment of a reasonable number of sounders in a large area, in order to update the simple statistical model, MINIMUF, yields MUF prediction capability on unsounded communication paths in the area within 0.4 MHz rms error. This value is obtained from real-time updating and a spatial interpolation process developed here, whereby data at sounder control points is interpolated to ionospheric reflection points for communication paths of interest. The results from the interpolation are found to be at least 20-30% more accurate than updating at any one of the nearby sounder control points. The updating procedure applies under day and night conditions, and also works well in a forecasting mode (not real-time), where it is found to work better in this case than a statistical trend line approach for daytime forecasting. (Author)

  19. An FPGA-Based Adaptable 200 MHz Bandwidth Channel Sounder for Wireless Communication Channel Characterisation

    Directory of Open Access Journals (Sweden)

    David L. Ndzi

    2011-01-01

    Full Text Available This paper describes the development of a fast adaptable FPGA-based wideband channel sounder with signal bandwidths of up to 200 MHz and channel sampling rates up to 5.4 kHz. The application of FPGA allows the user to vary the number of real-time channel response averages, channel sampling interval, and duration of measurement. The waveform, bandwidth, and frequency resolution of the sounder can be adapted for any channel under investigation. The design approach and technology used has led to a reduction in size and weight by more than 60%. This makes the sounder ideal for mobile time-variant wireless communication channels studies. Averaging allows processing gains of up to 30 dB to be achieved for measurement in weak signal conditions. The technique applied also improves reliability, reduces power consumption, and has shifted sounder design complexity from hardware to software. Test results show that the sounder can detect very small-scale variations in channels.

  20. Filling-in of far-red and near-Infrared solar lines by terrestrial and atmospheric effects: simulations and space-based observations from SCIAMACHY and GOSAT

    Directory of Open Access Journals (Sweden)

    J. Joiner

    2012-01-01

    Full Text Available Global mapping of terrestrial vegetation fluorescence from space has recently been accomplished with high spectral resolution (ν/Δν>35 000 measurements from the Japanese Greenhouse gases Observing SATellite (GOSAT. These data are of interest because they can potentially provide global information on the functional status of vegetation including light use efficiency and global primary productivity that can be used for global carbon cycle modeling. Quantifying the impact of fluorescence on the O2-A band is important as this band is used for cloud- and aerosol-characterization for other trace-gas retrievals including CO2. Here, we explore whether fluorescence information can be derived from space using potentially lower-cost hyperspectral instrumentation, i.e., more than an order of magnitude less spectral resolution (ν/Δν ∼1600 than GOSAT, with a relatively simple algorithm. We simulate the filling-in, from various atmospheric and terrestrial effects, of one of the few wide and deep solar Fraunhofer lines in the long-wave tail of the fluorescence emission region, the calcium (Ca II line near 866 nm. We then examine filling-in of this line using the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY satellite instrument. We develop and apply methodology to correct for various instrumental artifacts that produce false filling-in of solar lines in satellite radiance measurements. We then compare the derived additive near-InfraRed (NIR signal at 866 nm, that fills in the Ca II line, with larger signals retrieved at 758 and 770 nm on the shoulders of the O2-A feature from GOSAT that are presumably due primarily to vegetation fluorescence. Finally, we compare temporal and spatial variations of GOSAT and SCIAMACHY additive signals with those of the Enhanced Vegetation Index (EVI from the MODerate-resolution Imaging Spectroradiometer (MODIS. Although the

  1. Filling-in of far-red and near-Infrared solar lines by terrestrial and atmospheric effects: simulations and space-based observations from SCIAMACHY and GOSAT

    Science.gov (United States)

    Joiner, J.; Yoshida, Y.; Vasilkov, A. P.; Middleton, E. M.; Campbell, P. K. E.; Yoshida, Y.; Kuze, A.; Corp, L. A.

    2012-01-01

    Global mapping of terrestrial vegetation fluorescence from space has recently been accomplished with high spectral resolution (ν/Δν>35 000) measurements from the Japanese Greenhouse gases Observing SATellite (GOSAT). These data are of interest because they can potentially provide global information on the functional status of vegetation including light use efficiency and global primary productivity that can be used for global carbon cycle modeling. Quantifying the impact of fluorescence on the O2-A band is important as this band is used for cloud- and aerosol-characterization for other trace-gas retrievals including CO2. Here, we explore whether fluorescence information can be derived from space using potentially lower-cost hyperspectral instrumentation, i.e., more than an order of magnitude less spectral resolution (ν/Δν ∼1600) than GOSAT, with a relatively simple algorithm. We simulate the filling-in, from various atmospheric and terrestrial effects, of one of the few wide and deep solar Fraunhofer lines in the long-wave tail of the fluorescence emission region, the calcium (Ca) II line near 866 nm. We then examine filling-in of this line using the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) satellite instrument. We develop and apply methodology to correct for various instrumental artifacts that produce false filling-in of solar lines in satellite radiance measurements. We then compare the derived additive near-InfraRed (NIR) signal at 866 nm, that fills in the Ca II line, with larger signals retrieved at 758 and 770 nm on the shoulders of the O2-A feature from GOSAT that are presumably due primarily to vegetation fluorescence. Finally, we compare temporal and spatial variations of GOSAT and SCIAMACHY additive signals with those of the Enhanced Vegetation Index (EVI) from the MODerate-resolution Imaging Spectroradiometer (MODIS). Although the observed filling-in signal from SCIAMACHY is extremely weak at 866 nm, the

  2. Infrared astronomy

    International Nuclear Information System (INIS)

    This volume contains lectures describing the important achievements in infrared astronomy. The topics included are galactic infrared sources and their role in star formation, the nature of the interstellar medium and galactic structure, the interpretation of infrared, optical and radio observations of extra-galactic sources and their role in the origin and structure of the universe, instrumental techniques and a review of future space observations. (C.F.)

  3. Eastward traverse of equatorial plasma plumes observed with the Equatorial Atmosphere Radar in Indonesia

    OpenAIRE

    Fukao, S.; Yokoyama, T; T. Tayama; Yamamoto, M.; Maruyama, T.; Saito, S.

    2006-01-01

    The zonal structure of radar backscatter plumes associated with Equatorial Spread F (ESF), probably modulated by atmospheric gravity waves, has been investigated with the Equatorial Atmosphere Radar (EAR) in West Sumatra, Indonesia (0.20° S, 100.32° E; dip latitude 10.1° S) and the FM-CW ionospheric sounders on the same magnetic meridian as the EAR. The occurrence locations and zonal distances of the ESF plumes were determined with multi-beam obs...

  4. Eastward traverse of equatorial plasma plumes observed with the Equatorial Atmosphere Radar in Indonesia

    OpenAIRE

    Fukao, S.; Yokoyama, T; T. Tayama; Yamamoto, M.; Maruyama, T.; Saito, S.

    2006-01-01

    The zonal structure of radar backscatter plumes associated with Equatorial Spread F (ESF), probably modulated by atmospheric gravity waves, has been investigated with the Equatorial Atmosphere Radar (EAR) in West Sumatra, Indonesia (0.20° S, 100.32° E; dip latitude 10.1° S) and the FM-CW ionospheric sounders on the same magnetic meridian as the EAR. The occurrence locations and zonal distances of the ESF plumes were determined with multi-beam observations with t...

  5. Phase Change Material for Temperature Control of Imager or Sounder on GOES Type Satellites in GEO

    Science.gov (United States)

    Choi, Michael K.

    2014-01-01

    This paper uses phase change material (PCM) in the scan cavity of an imager or sounder on satellites in geostationary orbit (GEO) to maintain the telescope temperature stable. When sunlight enters the scan aperture, solar heating causes the PCM to melt. When sunlight stops entering the scan aperture, the PCM releases the thermal energy stored to keep the components in the telescope warm. It has no moving parts or bimetallic springs. It reduces heater power required to make up the heat lost by radiation to space through the aperture. It is an attractive thermal control option to a radiator with a louver and a sunshade.

  6. An approach towards solving refraction problems in EM1002 multi-beam echo-sounder system

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, W.A.

    -forming method…………………………………..phase interpolated Economic survey speed………………………………...7 knots Working sea state………………………………………3 - 3 - The EM1002 multi-beam echo-sounder system consists of several units out of which some important units... Technical Specifications. ------------------------------------------.2 2.2. Transducer Array. -------------------------------------------------------------------------.3 2.3. Transceiver unit...

  7. HF doppler sounder measurements of the ionospheric signatures of small scale ULF waves

    OpenAIRE

    Baddeley, L. J.; Yeoman, T.K.; Wright, D. M.

    2005-01-01

    An HF Doppler sounder, DOPE (DOppler Pulsation Experiment) with three azimuthally-separated propagation paths is used to provide the first statistical examination of small scale-sized, high m waves where a direct measurement of the azimuthal wavenumber m, is made in the ionosphere. The study presents 27 events, predominantly in the post-noon sector. The majority of events are Pc4 waves with azimuthal m numbers ranging from –100 to –200,...

  8. Validation of the Aura Microwave Limb Sounder Temperature and Geopotential Height Measurements

    OpenAIRE

    Schwartz, M.; Lambert, A.; Manney, G.L.; Read, W. G.; Livesey, N.J.; L. Froidevaux; C. O. Ao; Bernath, P. F.; Boone, C. D.; Cofield, R.E.; W. H. Daffer; Drouin, B.J.; E. J. Fetzer; Fuller, R. A.; Jarnot, R.F.

    2008-01-01

    Global satellite observations of temperature and geopotential height (GPH) from the Microwave Limb Sounder (MLS) on the EOS Aura spacecraft are discussed. The precision, resolution, and accuracy of the data produced by the MLS version 2.2 processing algorithms are quantified, and recommendations for data screening are made. Temperature precision is 1 K or better from 316 hPa to 3.16 hPa, degrading to ∼3 K at 0.001 hPa. The vertical resolution is 3 km at 31.6 hPa, degrading to 6 km at 316 hPa ...

  9. Validation of Aura Microwave Limb Sounder BrO observations in the stratosphere

    OpenAIRE

    J. Kovalenko, L.; L. Livesey, N.; J. Salawitch, R.; Camy-Peyret, C.; P. Chipperfield, M.; E. Cofield, R.; Dorf, M.; J. Drouin, B.; L. Froidevaux; Fuller, R. A.; Goutail, Florence; F. Jarnot, R.; Jucks, K.; W. Knosp, B.; Lambert, A.

    2007-01-01

    Validation of stratospheric BrO vertical profiles obtained by the Microwave Limb Sounder (MLS) on the Aura satellite is discussed. MLS BrO measurements are compared with expectations of its latitudinal and seasonal dependence, as well as with more localized balloon-borne measurements of BrO. We describe the expected precision and systematic errors of the version 2.2 retrieval and show that scientific studies using MLS BrO vertical profiles require extensive averaging to increase the signal-to...

  10. P-sounder: an airborne P-band ice sounding radar

    DEFF Research Database (Denmark)

    Dall, Jørgen; Skou, Niels; Kusk, Anders;

    2007-01-01

    This paper presents the top-level design of an airborne, P-band ice sounding radar under development at the Technical University of Denmark. The ice sounder is intended to provide more information on the electromagnetic properties of the Antarctic ice sheet at P-band. A secondary objective is to ...... digital signal generator, a microstrip antenna array, a conventional RF-architecture with a central transmitter, four receivers, and internal calibration loops. In 2008 the first data acquisition campaign will take place in Greenland....

  11. Wideband Dual-Polarization Microstrip Patch Antenna Array for Airborne Ice Sounder

    DEFF Research Database (Denmark)

    Vazquez-Roy, Jose Luis; Krozer, Viktor; Dall, Jørgen

    2012-01-01

    We present the design and realization of an antenna array based on cavity-backed microstrip patch antenna elements, with a relative operating bandwidth exceeding 20% at a return-loss level better than 15 dB. The antenna array of four elements did not show any compromise in bandwidth. It exhibited...... sidelobe levels better than 15 dB, with a gain of around 12 dBi. Excellent agreement was achieved between measurements and predictions for the designs of both the single element and the array. This antenna is part of the European Space Agency's airborne polarimetric P-band terrestrial ice sounder....

  12. A comprehensive observational filter for satellite infrared limb sounding of gravity waves

    Science.gov (United States)

    Trinh, Thai; Kalisch, Silvio; Preusse, Peter; Chun, Hye Yeong; Eckermann, Stephen D.; Ern, Manfred; Riese, Martin

    2015-04-01

    Infrared limb sounding provides valuable observations for understanding the dynamics of the middle atmosphere. For the interpretation of gravity wave (GW) observations, the observational filter plays a crucial role. We describe a comprehensive observational filter for this technique. Both instrument visibility and observation geometry are considered in this filter with a high level of accuracy. Four main aspects that influence the GW spectrum are discussed thoroughly. They are: (1) visibility filter, (2) projection of the horizontal wavelength on the tangent-point track, (3) aliasing effect, and (4) calculation of the observed vertical wavelength. Gravity waves simulated by coupling a convective GW source (CGWS) scheme with the gravity wave regional or global ray tracer (GROGRAT) are used as an example for applying the observational filter. The observation geometries of the satellite instruments SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) and HIRDLS (High Resolution Dynamics Limb Sounder) are considered. The visibility filter is found to be the most important aspect: it strongly influences the GWMF spectrum for both instruments. The second important aspect is aliasing for SABER, and projection on tangent-point track for HIRDLS. It is shown that the retrieval (a part of the "visibility filter" process) significantly affects the vertical wavelength distribution. For some cases, the short-horizontal-scale spectrum might be projected towards longer horizontal wavelengths where the original spectrum was not located. Also, GWMF values at very short horizontal wavelengths were significantly decreased due to the observational filter. In addition, we discuss the interpretation of observed data using this observational filter, as well as its applicability to other types of instruments.

  13. High-sensitivity remote detection of atmospheric pollutants and greenhouse gases at low ppm levels using near-infrared tunable diode lasers

    Science.gov (United States)

    Roy, Anirban; Upadhyay, Abhishek; Chakraborty, Arup Lal

    2016-05-01

    The concentration of atmospheric pollutants and greenhouse gases needs to be precisely monitored for sustainable industrial development and to predict the climate shifts caused by global warming. Such measurements are made on a continuous basis in ecologically sensitive and urban areas in the advanced countries. Tunable diode laser spectroscopy (TDLS) is the most versatile non-destructive technology currently available for remote measurements of multiple gases with very high selectivity (low cross-sensitivity), very high sensitivity (on the order of ppm and ppb) and under hazardous conditions. We demonstrate absolute measurements of acetylene, methane and carbon dioxide using a fielddeployable fully automated TDLS system that uses calibration-free 2f wavelength modulation spectroscopy (2f WMS) techniques with sensitivities of low ppm levels. A 40 mW, 1531.52 nm distributed feedback (DFB) diode laser, a 10 mW, 1650 nm DFB laser and a 1 mW, 2004 nm vertical cavity surface emitting laser (VCSEL) are used in the experiments to probe the P9 transition of acetylene, R4 transition of methane and R16 transition of carbon dioxide respectively. Data acquisition and on-board analysis comprises a Raspberry Pi-based embedded system that is controllable over a wireless connection. Gas concentration and pressure are simultaneously extracted by fitting the experimental signals to 2f WMS signals simulated using spectroscopic parameters obtained from the HITRAN database. The lowest detected concentration is 11 ppm for acetylene, 275 ppm for methane and 285 ppm for carbon dioxide using a 28 cm long single-pass gas cell.

  14. Analysis of far infrared spectra for the determination of the middle atmospheric OH concentration; Analyse von Fern-Infrarot-Spektren zur Bestimmung der OH-Konzentration der mittleren Erdatmosphaere

    Energy Technology Data Exchange (ETDEWEB)

    Schimpf, B.A.

    2000-02-01

    Inverse problems are frequently encountered in many fields of natural science and engineering, e.g., retrieval of atmospheric parameters from remote sensing spectral measurements is a typical inverse problem. Inverse problems are well known to be ill-posed because small perturbations in the measured data can lead to extreme perturbations of the retrieved solution. Physically meaningful solutions can be found by regularization, i.e., by introducing additional information, e.g., by using quadratic constraints. The L-curve criterion is a convenient tool to automatically find the optimal weighting of this constraint. A numerically robust implementation delivers additional diagnostics of the inverse problem and allows an efficient implementation of the L-curve criterion. After solving the inverse problem the quality of the solution has to be investigated. Thus, a detailed assessment of all error sources is mandatory. The methods for solving inverse problems and the detailed error analysis developed in this work are applied to the determination of the middle atmospheric OH concentration from far infrared spectra. In the theoretically oriented ESA study PIRAMHYD three satellite based limbsounding instruments (Fabry-Perot interferometer, Fourier transform spectrometer, and heterodyne spectrometer) were compared. The higher sensitivity of low spectral resolution instruments to systematic error sources was a major result of this study. Furthermore pointing error was identified to be the dominant error source for all instruments. In the second application data measured by the vertical sounding heterodyne spectrometer THOMAS flown in the MAHRSI validation campaign were analysed. Agreement of MAHRSI mesospheric and upper stratospheric OH measurements and the OH concentration determined by THOMAS within the overall error of the THOMAS measurements has been shown. (orig.)

  15. Infrared thermography

    CERN Document Server

    Meola, Carosena

    2012-01-01

    This e-book conveys information about basic IRT theory, infrared detectors, signal digitalization and applications of infrared thermography in many fields such as medicine, foodstuff conservation, fluid-dynamics, architecture, anthropology, condition monitoring, non destructive testing and evaluation of materials and structures.

  16. Intercomparison of polar ozone profiles by IASI/MetOp sounder with 2010 Concordiasi ozonesonde observations

    Directory of Open Access Journals (Sweden)

    J. Gazeaux

    2012-10-01

    Full Text Available Validation of ozone profiles measured from a nadir looking satellite instrument over Antarctica is a challenging task due to differences in their height sensitivity with ozonesonde measurements. In this paper we compare the ozone observations provided by the Infrared Atmospheric Sounding Interferometer (IASI instrument onboard the polar-orbiting satellite MetOp with ozone profiles collected between August and October 2010 at McMurdo Station, Antarctica, during the Concordiasi campaign. This campaign was aimed at satellite data validation and up to 20 zero-pressure sounding balloons carrying ozonesondes were launched during this period when the MetOp satellite was passing above McMurdo. This makes the dataset relevant for comparison, especially because those balloons covered the entire altitude range of IASI profiles. The validation methodology and the collocation criteria differ according to the availability of Global Positioning System auxiliary data with each Electro-Chemical Cell ozonesonde observation. We show that the relative mean difference depends on the altitude range investigated. The analysis shows a good agreement in the troposphere (below 10 km and middle stratosphere (25–40 km, where the differences are lower than 10%. However a significant positive bias of about 10–26% is estimated in the lower stratosphere at 10–25 km, depending on altitude. The positive bias in the 10–25 km range is consistent with previously reported studies comparing in-situ data with thermal infrared satellite measurements. This study allows a better characterization of the IASI products over the polar region when ozone depletion/recovery is occurring.

  17. The use of LinkWinds for the validation and analysis of 14 years of Microwave Sounder Unit daily global temperature anomaly data

    Science.gov (United States)

    Botts, Michael E.; Spencer, Roy W.

    1995-01-01

    Temperature data derived from the Microwave Sounder Unit (MSU) provides an opportunity for investigating atmospheric temperatures on a global scale since 1979. Fourteen years of global data sets of daily temperature anomalies within the lower stratosphere and lower troposphere are being generated at NASA Marshall Space Flight Center. LinkWinds, a visualization/analysis package under development at NASA Jet Propulsion Laboratory, has been extremely useful for validating and analyzing these data sets. LinkWinds provides the ability to interactively scroll and animate through the 10,220 images of temporal data, to selectively slice and view the data along latitude, longitude, or temporal axes, to interactively analyze spatial and temporal variability within the data, and to perform correlative analysis between various elements of the data. These capabilities have been invaluable in allowing the recognition of processing artifacts, as well as the effects that physical phenomena, such as the El Ninos effects and the Mt. Pinatubo eruption, have had on atmospheric temperatures.

  18. Satellite observation of atmospheric methane: intercomparison between AIRS and GOSAT TANSO-FTS retrievals

    Science.gov (United States)

    Zou, M.; Xiong, X.; Saitoh, N.; Warner, J.; Zhang, Y.; Chen, L.; Weng, F.

    2015-10-01

    Space-borne observations of atmospheric methane (CH4) have been made using the Atmospheric Infrared Sounder (AIRS) on the EOS/Aqua satellite since August 2002 and the Thermal and Near-infrared Sensor for Carbon Observation Fourier Transform Spectrometer (TANSO-FTS) on the Greenhouse Gases Observing Satellite (GOSAT) since April 2009. This study compared the GOSAT TANSO-FTS thermal infrared (TIR) version 1.0 CH4 product with the collocated AIRS version 6 CH4 product using data from 1 August 2010 to 30 June 2012, including the CH4 mixing ratios and the total column amounts. The results show that at 300-600 hPa, where both AIRS and GOSAT-TIR CH4 have peak sensitivities, they agree very well, but GOSAT-TIR retrievals tend to be higher than AIRS in layer 200-300 hPa. At 300 hPa the CH4 mixing ratio from GOSAT-TIR is, on average, 10.3 ± 31.8 ppbv higher than that from AIRS, and at 600 hPa GOSAT-TIR retrieved CH4 is -16.2 ± 25.7 ppbv lower than AIRS CH4. Comparison of the total column amount of CH4 shows that GOSAT-TIR agrees with AIRS to within 1 % in the mid-latitude regions of Southern Hemisphere and in tropics. In the mid to high latitudes in the Northern Hemisphere, GOSAT-TIR is ~ 1-2 % lower than AIRS, and in the high-latitude regions of Southern Hemisphere the difference of GOSAT from AIRS varies from -3 % in October to +2 % in July. The difference between AIRS and GOSAT TANSO-FTS retrievals is mainly due to the difference in retrieval algorithms and instruments itself, and the larger difference in the high latitude regions is associated with the low information content and small degree of freedoms of the retrieval. The degree of freedom of GOSAT-TIR retrievals is lower than that of AIRS also indicates that the constraint in GOSAT-TIR retrieval may be too strong. From the good correlation between AIRS and GOSAT-TIR retrievals and the seasonal variation they observed we are confident that the thermal infrared measurements from AIRS and GOSAT-TIR can provide

  19. Satellite observation of atmospheric methane: intercomparison between AIRS and GOSAT TANSO-FTS retrievals

    Science.gov (United States)

    Zou, Mingmin; Xiong, Xiaozhen; Saitoh, Naoko; Warner, Juying; Zhang, Ying; Chen, Liangfu; Weng, Fuzhong; Fan, Meng

    2016-08-01

    Space-borne observations of atmospheric methane (CH4) have been made using the Atmospheric Infrared Sounder (AIRS) on the EOS/Aqua satellite since August 2002 and the Thermal and Near-infrared Sensor for Carbon Observation Fourier Transform Spectrometer (TANSO-FTS) on the Greenhouse Gases Observing Satellite (GOSAT) since April 2009. This study compared the GOSAT TANSO-FTS thermal infrared (TIR) version 1.0 CH4 product with the collocated AIRS version 6 CH4 product using data from 1 August 2010 to 30 June 2012, including the CH4 mixing ratios and the total column amounts. The results show that at 300-600 hPa, where both AIRS and GOSAT-TIR CH4 have peak sensitivities, they agree very well, but GOSAT-TIR retrievals tend to be higher than AIRS in layer 200-300 hPa. At 300 hPa the CH4 mixing ratio from GOSAT-TIR is, on average, 10.3 ± 31.8 ppbv higher than that from AIRS, and at 600 hPa GOSAT-TIR retrieved CH4 is -16.2 ± 25.7 ppbv lower than AIRS CH4. Comparison of the total column amount of CH4 shows that GOSAT-TIR agrees with AIRS to within 1 % in the mid-latitude regions of the Southern Hemisphere and in the tropics. In the mid to high latitudes in the Northern Hemisphere, comparison shows that GOSAT-TIR is ˜ 1-2 % lower than AIRS, and in the high-latitude regions of the Southern Hemisphere the difference of GOSAT from AIRS varies from -3 % in October to +2 % in July. The difference between AIRS and GOSAT TANSO-FTS retrievals is mainly due to the difference in retrieval algorithms and instruments themselves, and the larger difference in the high-latitude regions is associated with the low information content and small degrees of freedom of the retrieval. The degrees of freedom of GOSAT-TIR retrievals are lower than that of AIRS, which also indicates that the constraint in GOSAT-TIR retrievals may be too strong. From the good correlation between AIRS and GOSAT-TIR retrievals and the seasonal variation they observed, we are confident that the thermal infrared

  20. Submillimeter limb-emission sounder JEM/SMILES aboard the Space Station

    Science.gov (United States)

    Inatani, Junji; Ozeki, Hiroyuki; Satoh, Ryouta; Nishibori, Toshiyuki; Ikeda, Naomi; Fujii, Yasunori; Nakajima, Takashi; Iida, Yukiei; Iida, Teruhito; Kikuchi, Ken'ichi; Miura, Takeshi; Masuko, Harunobu; Manabe, Takeshi; Ochiai, Satoshi; Seta, Masumichi; Irimajiri, Yoshihisa; Kasai, Yasuko; Suzuki, Makoto; Shirai, Tomoko; Tsujimaru, Sho; Shibasaki, Kazuo; Shiotani, Masato

    2000-12-01

    A submillimeter limb-emission sounder, that is to be aboard the Japanese Experiment Module (JEM, dubbed as KIBO) at the International Space Station, has been designed. This payload, Superconducting Submillimeter-wave Limb-emission Sounder (SMILES), is aimed at global mappings of stratospheric trace gases by means of the most sensitive submillimeter receiver ever operated in space. Such sensitivity is ascribed to a Superconductor-Insulator- Superconductor (SIS) mixer, which is operated at 4.5 K in a dedicated cryostat combined with a mechanical cooler. SMILES will observe ozone-depletion-related molecules such as ClO, Hcl, HO2, HNO3, BrO and O3 in the frequency bands at 624.32-626.32 GHz and 649.12-650.32 GHz. A scanning antenna will cover tangent altitudes from 10 to 60 km in every 53 seconds, while tracing the latitudes form 38 S to 65 N along its orbit. This global coverage makes SMILES a useful tool of observing the low- and mid- latitudinal areas as well as the Arctic peripheral region. The molecular emissions will be detected by two units of acousto-optic spectrometers (AOS), each of which has coverage of 1.2 GHz with a resolution of 1.8 MHz. This high-resolution spectroscopy will allow us to detect weak emission lines attributing to less-abundant species.

  1. ULF wave occurrence statistics in a high-latitude HF Doppler sounder

    Directory of Open Access Journals (Sweden)

    D. M. Wright

    Full Text Available Ultra low frequency (ULF wave activity in the high-latitude ionosphere has been observed by a high frequency (HF Doppler sounder located at Tromsø, Norway (69.7°N, 19.2°E geographic coordinates. A statistical study of the occurrence of these waves has been undertaken from data collected between 1979 and 1984. The diurnal, seasonal, solar cycle and geomagnetic activity variations in occurrence have been investigated. The findings demonstrate that the ability of the sounder to detect ULF wave signatures maximises at the equinoxes and that there is a peak in occurrence in the morning sector. The occurrence rate is fairly insensitive to changes associated with the solar cycle but increases with the level of geomagnetic activity. As a result, it has been possible to characterise the way in which prevailing ionospheric and magnetospheric conditions affect such observations of ULF waves.

    Key words. Ionosphere (auroral ionosphere; ionosphere -magnetosphere interactions · Magnetospheric physics (MHD waves and instabilities

  2. The Whisper Relaxation Sounder onboard Cluster: A Powerful Tool for Space Plasma Diagnosis around the Earth

    International Nuclear Information System (INIS)

    The WHISPER relaxation sounder that is onboard the four CLUSTER spacecraft has for main scientific objectives to monitor the natural waves in the 2 kHz - 80 kHz frequency range and, mostly, to determine the total plasma density from the solar wind down to the Earth's plasmasphere. To fulfil these objectives, the WHISPER uses the two long double sphere antennae of the Electric Field and Wave experiment as transmitting and receiving sensors. In its active working mode, the WHISPER works according to principles that have been worked out for topside sounding. A radio wave transmitter sends an almost monochromatic and short wave train. A few milliseconds after, a receiver listens to the surrounding plasma response. Strong and long lasting echoes are actually received whenever the transmitting frequencies coincide with characteristic plasma frequencies. Provided that these echoes, also called resonances, may be identified, the WHISPER relaxation sounder becomes a reliable and powerful tool for plasma diagnosis. When the transmitter is off, the WHISPER behaves like a passive receiver, allowing natural waves to be monitored. The paper aims mainly at the resonance identification process description and the WHISPER capabilities and performance highlighting. (author)

  3. Sounder stimulated D(sub n) resonances in Jupiter's Io plasma torus

    Science.gov (United States)

    Osherovich, V. A.; Benson, R. F.; Fainberg, J.; Stone, R. G.; Macdowall, R. J.

    1993-01-01

    On February 8, 1992, the Ulysses spacecraft passed through Jupiter's Io plasma torus, where rich spectra of narrow-band resonances were stimulated by the relaxation sounder of the Ulysses unified radio and plasma wave (URAP) instrument. Since the gyrofrequency f(sub g) is comparable to the plasma frequency f(sub p) in the Io torus, it was predicted that the general classification of stimulated ionospheric D(sub n) resonances, developed for 1 is less than or equal to f(sub p)/f(sub g) is less than or equal to 8 in the Earth's topside ionosphere, should apply in the Io torus as well as the Earth's magnetosphere (Osherovich, 1989). The URAP plasmagrams (sounder spectra) in the portions of the Io torus satisfying these plasma conditions are dominated by the D(sub n) resonances for frequencies below f(sub p). On most of these plasmagrams the f(sub p) resonance is also present, but it is seldom the dominant resonance. Neither upper hybrid nor nf(sub g) resonances have been found on these plasmagrams. The identification of D(sub n) resonances has allowed both the electron density and the magnetic field amplitude to be calculated. The derived densities on the outbound pass agree well with a Voyager model of Bagenal (1992). The derived magnetic field values are close to the Goddard Space Flight Center O(sub 6) magnetic field model.

  4. Jupiter Eruptions Captured in Infrared

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers. This infrared image shows two bright plume eruptions obtained by the NASA Infrared Telescope Facility on April 5, 2007. Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena. According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vigorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

  5. Measure and exploitation of multisensor and multiwavelength synergy for remote sensing: 2. Application to the retrieval of atmospheric temperature and water vapor from MetOp

    Science.gov (United States)

    Aires, Filipe; Paul, Maxime; Prigent, Catherine; Rommen, BjöRn; Bouvet, Marc

    2011-01-01

    In the companion paper, classical information content (IC) analysis was used to measure the potential synergy between the microwave (MW) and infrared (IR) observations from Atmospheric Microwave Sounding Unit-A, Microwave Humidity Sounder, and Improved Atmospheric Sounding in the Infrared instruments, used to retrieve the atmospheric profiles of temperature and water vapor over ocean, under clear-sky conditions. Some limitations of IC were pointed out that questioned the reliability of this technique for synergy characterization. The goal of this second paper is to develop a methodology to measure realistic potential synergies and to construct retrieval methods able to exploit them. Three retrieval methods are considered: the k nearest neighbors, the linear regression, and the neural networks (NN). These statistical retrieval schemes are tested on an application involving IR and MW synergy. Only clear-sky, near-nadir radiances over ocean are considered. The IR/MW synergy is expected to be stronger in cloudy cases, but it will be shown that it can also be observed in clear situations. The inversion algorithms are calibrated and tested with simulated observations, without any loss of generality, using similar theoretical assumption (same radiative transfer model, observational noise, and a priori information) in order to truly compare the IC and the direct statistical retrieval approaches. Multivariate and nonlinear methods such as the NN approach show that there is a strong potential for synergy. Synergy measurement tools such as the method proposed in this study should be considered in the future for the definition of new missions: The instrument characteristics should be determined not independently, sensor by sensor, but taking into account all the instruments together as a whole observing system.

  6. Measurement of stratospheric and mesospheric winds with a submillimeter wave limb sounder: results from JEM/SMILES and simulation study for SMILES-2

    Science.gov (United States)

    Baron, Philippe; Manago, Naohiro; Ozeki, Hiroyuki; Irimajiri, Yoshihisa; Murtagh, Donal; Uzawa, Yoshinori; Ochiai, Satoshi; Shiotani, Masato; Suzuki, Makoto

    2015-10-01

    Satellite missions for measuring winds in the troposphere and thermosphere will be launched in a near future. There is no plan to observe winds in the altitude range between 30-90 km, though middle atmospheric winds are recognized as an essential parameter in various atmospheric research areas. Sub-millimetre limb sounders have the capability to fill this altitude gap. In this paper, we summarize the wind retrievals obtained from the Japanese Superconducting Submillimeter Wave Limb Emission Sounder (SMILES) which operated from the International Space Station between September 2009 and April 2010. The results illustrate the potential of such instruments to measure winds. They also show the need of improving the wind representation in the models in the Tropics, and globally in the mesosphere. A wind measurement sensitivity study has been conducted for its successor, SMILES-2, which is being studied in Japan. If it is realized, sub-millimeter and terahertz molecular lines suitable to determine line-of-sight winds will be measured. It is shown that with the current instrument definition, line-of-sight winds can be observed from 20 km up to more than 160 km. Winds can be retrieved with a precision better than 5 ms-1 and a vertical resolution of 2-3 km between 35-90 km. Above 90 km, the precision is better than 10 ms-1 with a vertical resolution of 3-5 km. Measurements can be performed day and night with a similar sensitivity. Requirements on observation parameters such as the antenna size, the satellite altitude are discussed. An alternative setting for the spectral bands is examined. The new setting is compatible with the general scientific objectives of the mission and the instrument design. It allows to improve the wind measurement sensitivity between 35 to 90 km by a factor 2. It is also shown that retrievals can be performed with a vertical resolution of 1 km and a precision of 5-10 ms-1 between 50 and 90 km.

  7. Remote measurement of atmospheric pollutants

    Science.gov (United States)

    Allario, F.; Hoell, J.; Seals, R. K.

    1979-01-01

    The concentration and vertical distribution of atmospheric ammonia and ozone are remotely sensed, using dual-C02-laser multichannel infrared Heterodyne Spectrometer (1HS). Innovation makes atmospheric pollution measurements possible with nearly-quantum-noise-limited sensitivity and ultrafine spectral resolution.

  8. Observation of reproductive behaviour of the common bream .i.Abramis Brama./i. by scientific echo sounder

    Czech Academy of Sciences Publication Activity Database

    Prchalová, M.; Kubečka, Jan

    Montpellier: ICES, 2002. s. 131-132. [6th ICES Symposium on Acoustics in Fisheries and Aquatic Ecology, Book of Abstracts.. 10.06.2002-14.06.2002, Montpellier] Institutional research plan: CEZ:AV0Z6017912 Keywords : spawning * echo sounder * Abramis Subject RIV: EH - Ecology, Behaviour

  9. Effect of HF Emission of the topside sounder transmitter aboard the COSMOS-1809 satellite on the ionospheric plasma

    Science.gov (United States)

    Baranets, N. V.; Gladyshev, V. A.; Afonin, V. V.

    The experiment on investigation of effect of the HF emission (300 W) by the dipole antenna on the ionospheric plasma was carried out onboard the COSMOS-1809 satellite (1987). The sounder accelerated particles (SAP) at the electron cyclotron harmonics n x omegace and in the frequency region of antenna resonance were detected by the charged particle spectrometer.

  10. 利用MODIS红外资料反演大气温湿度廓线的研究%Study on the remote retrieval of atmospheric temperature and moisture profile based on MODIS infrared data

    Institute of Scientific and Technical Information of China (English)

    曲思邈; 李国春

    2012-01-01

    概述了利用特征向量统计回归反演算法,从EOS/MODIS的红外通道资料反演大气温湿度垂直分布过程,并与美国国家环境预报中心NCEP(National Centers for Environmental Prediction)等压面再分析场资料按照纬度和气压高度进行了真实性检验。结果表明:由MODIS资料反演得到的大气温湿度参数能够揭示大气温湿度的垂直分布。在各个等压面上均方根误差平均值在中纬度地区为3.39K,低纬度地区为1.40K,近地面层、对流层顶附近及下垫面地形复杂的区域误差较大,总体上低纬度地区要好于中纬度地区。反演的水汽误差也为低纬度地区小于中纬度地区,且随高度升高,中、高纬度误差均逐渐减小并接近。%The retrieval algorithm based on an eigenvector regression method was summarized. The vertical distri- butions of the atmospheric temperature and moisture were retrieved using EOS/MODIS infrared data and were verified along the latitude and pressure altitude with isobaric surface reanalysis field data from NCEP ( national centers for environmental prediction). The results indicate that the atmospheric temperature and moisture parameters retrieved by MODIS data can reveal its vertical distributions. The average of root mean square (RMS) errors at each isobaric surface is 3.39 K in middle latitude region and 1.40 K in low latitude region, respectively. The errors are significant near the ground and tropopause region as well as in complicated underlying surface region. In general, temperature retrieval results are better in low latitude regions than in middle latitude regions, so are vapor retrieval results. With the increasing of the height, the error decreases gradually in middle and high latitudes regions and is close to each other.

  11. A new method for continuous measurements of oceanic and atmospheric N2O, CO and CO2: performance of off-axis integrated cavity output spectroscopy (OA-ICOS coupled to non-dispersive infrared detection (NDIR

    Directory of Open Access Journals (Sweden)

    D. L. Arévalo-Martínez

    2013-07-01

    Full Text Available A new system for continuous, highly-resolved oceanic and atmospheric measurements of N2O, CO and CO2 is described. The system is based upon off-axis integrated cavity output spectroscopy (OA-ICOS and a non-dispersive infrared analyzer (NDIR both coupled to a Weiss-type equilibrator. Performance of the combined setup was evaluated by testing its precision, accuracy, long-term stability, linearity and response time. Furthermore, the setup was tested during two oceanographic campaigns in the equatorial Atlantic Ocean in order to explore its potential for autonomous deployment onboard voluntary observing ships (VOS. Improved equilibrator response times for N2O (2.5 min and CO (45 min were achieved in comparison to response times from similar chamber designs used by previous studies. High stability of the OA-ICOS analyzer was demonstrated by low optimal integration times of 2 and 4 min for N2O and CO respectively, as well as detection limits of −1/2. Results from a direct comparison of the method presented here and well-established discrete methods for oceanic N2O and CO2 measurements showed very good consistency. The favorable agreement between underway atmospheric N2O, CO and CO2 measurements and monthly means at Ascension Island (7.96° S 14.4° W further suggests a reliable operation of the underway setup in the field. The potential of the system as an improved platform for measurements of trace gases was explored by using continuous N2O and CO2 data to characterize the development of the seasonal equatorial upwelling in the Atlantic Ocean during two R/V Maria S. Merian cruises. A similar record of high-resolution CO measurements was simultaneously obtained offering for the first time the possibility of a comprehensive view on the distribution and emissions of these climate relevant gases on the area. The relatively simple underway N2O/CO/CO2 setup is suitable for long-term deployment on board of research and commercial vessels although

  12. Barrier infrared detector

    Science.gov (United States)

    Ting, David Z. (Inventor); Khoshakhlagh, Arezou (Inventor); Soibel, Alexander (Inventor); Hill, Cory J. (Inventor); Gunapala, Sarath D. (Inventor)

    2012-01-01

    A superlattice-based infrared absorber and the matching electron-blocking and hole-blocking unipolar barriers, absorbers and barriers with graded band gaps, high-performance infrared detectors, and methods of manufacturing such devices are provided herein. The infrared absorber material is made from a superlattice (periodic structure) where each period consists of two or more layers of InAs, InSb, InSbAs, or InGaAs. The layer widths and alloy compositions are chosen to yield the desired energy band gap, absorption strength, and strain balance for the particular application. Furthermore, the periodicity of the superlattice can be "chirped" (varied) to create a material with a graded or varying energy band gap. The superlattice based barrier infrared detectors described and demonstrated herein have spectral ranges covering the entire 3-5 micron atmospheric transmission window, excellent dark current characteristics operating at least 150K, high yield, and have the potential for high-operability, high-uniformity focal plane arrays.

  13. Whisper, a resonance sounder and wave analyser: Performances and perspectives for the Cluster mission

    DEFF Research Database (Denmark)

    Decreau, P.M.E.; Fergeau, P.; KrannoselsKikh, V.; Leveque, M.; Martin, Paulo; Randriamboarison, O.; Sene, F.X.; Trotignon, J.G.; Canu, P.; Mogensen, P.B.; Vasiljevic, C.; Guyot, E.; Launay, L.; CornilleauWehrlin, N.; deFeraudy, H.; Iversen, I.; Gustafsson, G.; Gurnett, D.; Woolliscroft, L.

    The WHISPER sounder on the Cluster spacecraft is primarily designed to provide an absolute measurement of the total plasma density within the range 0.2-80 cm(-3). This is achieved by means of a resonance sounding technique which has already proved successful in the regions to be explored. The wave...... mode. Special attention has been paid to the coordination of WHISPER operations with the wave instruments, as well as with the low-energy particle counters. When operated from the multi-spacecraft Cluster, the WHISPER instrument is expected to contribute in particular to the study of plasma waves in...... the electron foreshock and solar wind, to investigations about small-scale structures via density and high-frequency emission signatures, and to the analysis of the non-thermal continuum in the magnetosphere....

  14. Ionospheric tsunami disturbances probed by HF Doppler sounder, ionosonde and ground-based GPS TEC

    Science.gov (United States)

    Chen, Wei-Suan; Liu, Jann-Yenq Tiger; Wu, Tso-Ren; Tsai, Yu-Lin

    2016-04-01

    Tsunami waves induced by the 26 December 2004 Mw 9.3 Sumatra earthquake, the 11 March 2011 Mw 9.0 Tohoku earthquake, and the 16 September 2015 Mw 8.2 Chile earthquake are recorded by tide gauges around Taiwan. In this paper, the tsunami waves are studied by the tide gauge data and Cornell Multi-grid Coupled of Tsunami Model (COMCOT) simulations, while ionospheric tsunami disturbances (ITDs) are probed by the HF Doppler sounder with a sounding frequency of 5.26 MHz, ionosonde, and GPS TEC derived by ground-based GPS receivers in Taiwan. It is found that ITDs tend to lead their associated tsunami by about 30-60 minutes. A comparison between ITDs and tsunami waves will be presented and discussed.

  15. ESA'S POLarimetric Airborne Radar Ice Sounder (POLARIS): design and first results

    DEFF Research Database (Denmark)

    Dall, Jørgen; Kristensen, Steen Savstrup; Krozer, Viktor;

    2010-01-01

    been encountered. ESA s POLarimetric Airborne Radar Ice Sounder (POLARIS) is intended to provide a better understanding of P-band scattering and propagation through ice sheets and to verify novel surface clutter suppression techniques in preparation for a potential space-based ice sounding mission....... POLARIS is a nadir-looking, fully polarimetric radar featuring aperture synthesis, a multi-aperture antenna for surface clutter suppression and a large dynamic range based on a shallow/deep sounding approach. The system is installed in a De Haviland DHC-6 Twin Otter aircraft, and in May 2008, a proof......-of-concept campaign was conducted in Greenland. This study outlines the design and implementation of the system, and based on first results it is concluded that in the central dry snow zone of Greenland, POLARIS can resolve shallow and deep internal ice layers, penetrate the thickest ice encountered and detect...

  16. Navigation Signal Disturbances by Multipath Propagation - Scaled Measurements with a Universal Channel Sounder Architecture

    Science.gov (United States)

    Geise, Robert; Neubauer, Bjoern; Zimmer, Georg

    2015-11-01

    The performance of navigation systems is always reduced by unwanted multipath propagation. This is especially of practical importance for airborne navigation systems like the instrument landing system (ILS) or the VHF omni directional radio range (VOR). Nevertheless, the quantitative analysis of corresponding, potentially harmful multipath propagation disturbances is very difficult due to the large parameter space. Experimentally difficulties arise due to very expensive, real scale measurement campaigns and numerical simulation techniques still have shortcomings which are briefly discussed. In this contribution a new universal approach is introduced on how to measure very flexibly multipath propagation effects for arbitrary navigation systems using a channel sounder architecture in a scaled measurement environment. Two relevant scenarios of multipath propagation and the impact on navigation signals are presented. The first describes disturbances of the ILS due to large taxiing aircraft. The other example shows the influence of rotating wind turbines on the VOR.

  17. Preliminary Regional Analysis of the Kaguya Lunar Radar Sounder (LRS) Data through Eastern Mare Imbrium

    Science.gov (United States)

    Cooper, B.L.; Antonenko, I.; Yamaguchi, Y.; Osinski, G.; Ono, T.; Ku-mamoto, A.

    2009-01-01

    The Lunar Radar Sounder (LRS) experiment on board the Kaguya spacecraft is observing the subsurface structure of the Moon, using ground-penetrating radar operating in the frequency range of 5 MHz [1]. Because LRS data provides in-formation about lunar features below the surface, it allows us to improve our understanding of the processes that formed the Moon, and the post-formation changes that have occurred (such as basin formation and volcanism). We look at a swath of preliminary LRS data, that spans from 7 to 72 N, and from 2 to 10 W, passing through the eastern portion of Mare Imbrium (Figure 1). Using software, designed for the mineral exploration industry, we produce a preliminary, coarse 3D model, showing the regional structure beneath the study area. Future research will involve smaller subsets of the data in regions of interest, where finer structures, such as those identified in [2], can be studied.

  18. Tropical cyclone track and genesis forecasting using satellite microwave sounder data

    Science.gov (United States)

    Kidder, S. Q.

    1982-01-01

    Although many dynamical and statistical prediction schemes are available to forecasters, tropical cyclone track errors are still large. One primary difficulty is that tropical cyclones exist over the data-sparse tropical oceans. Satellite sounders, however, routinely provide numerous data over these areas. Mean layer temperatures from the Scanning Microwave Spectrometer on board the Nimbus 6 satellite are decomposed using empirical orthogonal functions, and the expansion coefficients are related to deviations from the persistence forecast location, to speed change, to direction change and to intensity change. The significance of the regression equations is tested by a null hypothesis of zero correlation coefficient. It appears that significant information about tropical cyclone motion exists in the satellite-estimated mean layer temperatures, especially at upper levels. A physical interpretation of the statistical results is offered, and a one-storm-out independent test is used to test the stability of the equations. Finally, some further work is suggested.

  19. Atmospheric Motion Vectors from INSAT-3D: Initial quality assessment and its impact on track forecast of cyclonic storm NANAUK

    Science.gov (United States)

    Deb, S. K.; Kishtawal, C. M.; Kumar, Prashant; Kiran Kumar, A. S.; Pal, P. K.; Kaushik, Nitesh; Sangar, Ghansham

    2016-03-01

    The advanced Indian meteorological geostationary satellite INSAT-3D was launched on 26 July 2013 with an improved imager and an infrared sounder and is placed at 82°E over the Indian Ocean region. With the advancement in retrieval techniques of different atmospheric parameters and with improved imager data have enhanced the scope for better understanding of the different tropical atmospheric processes over this region. The retrieval techniques and accuracy of one such parameter, Atmospheric Motion Vectors (AMV) has improved significantly with the availability of improved spatial resolution data along with more options of spectral channels in the INSAT-3D imager. The present work is mainly focused on providing brief descriptions of INSAT-3D data and AMV derivation processes using these data. It also discussed the initial quality assessment of INSAT-3D AMVs for a period of six months starting from 01 February 2014 to 31 July 2014 with other independent observations: i) Meteosat-7 AMVs available over this region, ii) in-situ radiosonde wind measurements, iii) cloud tracked winds from Multi-angle Imaging Spectro-Radiometer (MISR) and iv) numerical model analysis. It is observed from this study that the qualities of newly derived INSAT-3D AMVs are comparable with existing two versions of Meteosat-7 AMVs over this region. To demonstrate its initial application, INSAT-3D AMVs are assimilated in the Weather Research and Forecasting (WRF) model and it is found that the assimilation of newly derived AMVs has helped in reduction of track forecast errors of the recent cyclonic storm NANAUK over the Arabian Sea. Though, the present study is limited to its application to one case study, however, it will provide some guidance to the operational agencies for implementation of this new AMV dataset for future applications in the Numerical Weather Prediction (NWP) over the south Asia region.

  20. NOAA Climate Data Record (CDR) of Monthly Outgoing Longwave Radiation (OLR), Version 2.2-1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This Climate Data Record (CDR) of monthly mean High Resolution Infrared Radiation Sounder (HIRS) Outgoing Longwave Radiation (OLR) flux at the top of the atmosphere...

  1. Effects of the surface alb edo on short-wave infrared detection of atmospheric CO2%地表反照率对短波红外探测大气CO2的影响∗

    Institute of Scientific and Technical Information of China (English)

    陈洁; 张淳民; 王鼎益; 张兴赢; 王舒鹏; 栗彦芬; 刘冬冬; 荣飘

    2015-01-01

    The greenhouse gas carbon dioxide, for which short-wave infrared remote sensing detection is carried out by using satellite sensors to measure the Earth’s atmosphere scattering solar radiation, and makes use of the inversion algorithm to achieve measurements. Most of the solar radiation enter the satellite sensors after surface reflection, so the surface albedo which reflects the surface features is one of the important parameters which affect the accuracy of the detection. Aiming at the great demands of high precision carbon dioxide for greenhouse gas, this study first investigate the effects of the Earth’s surface albedo on the observed spectra. Simulation results show that the increase in the surface albedo will enhance the observed spectral intensity, especially larger in the O2-A band than in the 1.6 µm band. In other words, the surface albedo has a greater impact on O2-A ban. In the actual satellite inversio, the surface types of actual observation pointare uncertain, which will result in the error of surface albedo. Effect of surface albedo on the inverted XCO2 is analyzed when the surface albedo is changed by changing the type of surfac. Two observation cases are analyzed in detail. One is on April 23, 2009 for the desert surface, and another on May 21, 2013 for the grass surfac. Results show that when the O2-A band surface albedo approximates to the real surface albedo valu, the relative error of the inverted XCO2 is the smaller. If the relative changes of the O2-A band surface albedo exceed 0.25 in the grass surfac or 0.35 in the desert surface, the relative error of the inverted XCO2 will be greater than 1%, not satisfying the design requirement of the inversion system. In contrast, the changesin 1.6 µm band surface albedo have negligible effect on the inverted XCO2. This study shows the importance of surface albedo in the process of satellite remote sensin, and provides an important theoretical basis and guidance for improving the accuracy of

  2. Stratospheric Observatory for Infrared Astronomy

    CERN Document Server

    Hamidouche, M; Marcum, P; Krabbe, A

    2010-01-01

    We present one of the new generations of observatories, the Stratospheric Observatory For Infrared Astronomy (SOFIA). This is an airborne observatory consisting of a 2.7-m telescope mounted on a modified Boeing B747-SP airplane. Flying at an up to 45,000 ft (14 km) altitude, SOFIA will observe above more than 99 percent of the Earth's atmospheric water vapor allowing observations in the normally obscured far-infrared. We outline the observatory capabilities and goals. The first-generation science instruments flying on board SOFIA and their main astronomical goals are also presented.

  3. Infrared retina

    Science.gov (United States)

    Krishna, Sanjay; Hayat, Majeed M.; Tyo, J. Scott; Jang, Woo-Yong

    2011-12-06

    Exemplary embodiments provide an infrared (IR) retinal system and method for making and using the IR retinal system. The IR retinal system can include adaptive sensor elements, whose properties including, e.g., spectral response, signal-to-noise ratio, polarization, or amplitude can be tailored at pixel level by changing the applied bias voltage across the detector. "Color" imagery can be obtained from the IR retinal system by using a single focal plane array. The IR sensor elements can be spectrally, spatially and temporally adaptive using quantum-confined transitions in nanoscale quantum dots. The IR sensor elements can be used as building blocks of an infrared retina, similar to cones of human retina, and can be designed to work in the long-wave infrared portion of the electromagnetic spectrum ranging from about 8 .mu.m to about 12 .mu.m as well as the mid-wave portion ranging from about 3 .mu.m to about 5 .mu.m.

  4. Intercomparison of daytime stratospheric NO2 satellite retrievals and model simulations

    OpenAIRE

    M. Belmonte Rivas; P. Veefkind; BOERSMA F; P. Levelt; Eskes, H.; J. Gille

    2014-01-01

    This paper evaluates the agreement between stratospheric NO2 retrievals from infrared limb sounders (Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and High Resolution Dynamics Limb Sounder (HIRDLS)) and solar UV/VIS backscatter sensors (Ozone Monitoring Instrument (OMI), Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) limb and nadir) over the 2005–2007 period and across the seasons. The observational agreement ...

  5. Some results of analysis of inverted echo-sounder records from the Atlantic Equatorial region

    Directory of Open Access Journals (Sweden)

    Alberto dos Santos Franco

    1985-01-01

    Full Text Available The tidal analysis of data from the Equatorial region, given by inverted echo-sounders, show considerable residuals in the frequency band of approximately 2 cycles per day. In the even harmonics of 4 and 6 cycles per day, tidal components statistically not negligible are also identified. Spectral analysis of temperature series from the same area show, on the other hand, variabilities in the same frequency bands, which suggests the occurrence of internal waves with energy distributed in these frequency bands, in the Atlantic Equatorial area.Análises de dados de maré, da zona equatorial, obtidos com ecobatímetros invertidos, mostram consideráveis resíduos na faixa de freqüências com aproximadamente dois ciclos por dia. Nos harmônicos pares com 4 e 6 ciclos por dia são também identificadas componentes de maré estatisticamente não desprezíveis. Análises espectrais de séries de temperatura obtidas na mesma área mostram, 218 por outro lado, variabilidades na mesma faixa de freqüências, o que sugere a ocorrência, na área equatorial Atlântica, de ondas internas com energia distribuída nessas faixas espectrais.

  6. Tropical deep convection and density current signature on surface pressure: comparison of idealized and real WRF simulations with infra-sounder measurements

    Science.gov (United States)

    Costantino, Lorenzo; Heinrich, Philippe

    2013-04-01

    In the framework of the ARISE (Atmospheric dynamics Research InfraStructure in Europe) project, which proposes to design a new infrastructure to integrate different atmospheric observation networks, we analyse moist deep convective processes responsible of intensive rainstorms in the tropics (making use of the Weather Research and Forecasting, WRF, numerical model) and compare the results with ground measurements of the CTBTO (Comprehensive nuclear-Test-Ban Treaty Organization) infra-sound stations in Ivory Coast. In this work, we investigate the life cycle of singlecell deep convective cloud trough a bi-dimensional, non-hydrostatic, limited-area simulation in simplified model configuration ("idealized case"), at high spatial and temporal resolution. In this way, we expect to resolve explicitly the convective cloud dynamics, avoiding the use of sometimes questionable parametrization (e.g. PBL and convective cumulus) schemes. We also perform a three-dimensional numerical experiment at coarser resolution, guided by real meteorological data of the tropical Ivory Coast region, to compare "real case" results with the infra-sounder measurements for the same area. Previous studies have shown that rain evaporation during intense precipitating events may cool the atmosphere and produce negative buoyancy that, together with falling rain, may give rise to particularly strong down-drafts (Betts, 1976, Tompkins, 2000). As the descending air column impacts the ground, it spreads out and creates a horizontal surface outflow (generally called "density current" or "cold pool") colder and denser than surrounding air. Results from the 2D idealized case show that temporal and horizontal resolution of 2 seconds and 250 meters is fine enough to produce a density current, that moves outward up to several kilometers from storm center. The increase in surface density (up to 2% higher than the base state) is followed by a sudden variation of surface temperature and an increase in horizontal

  7. A Search for Magnesium in Europa's Atmosphere

    OpenAIRE

    Horst, Sarah M.; Brown, Michael E.

    2013-01-01

    Europa's tenuous atmosphere results from sputtering of the surface. The trace element composition of its atmosphere is therefore related to the composition of Europa's surface. Magnesium salts are often invoked to explain Galileo Near Infrared Mapping Spectrometer spectra of Europa's surface, thus magnesium may be present in Europa's atmosphere. We have searched for magnesium emission in the Hubble Space Telescope Faint Object Spectrograph archival spectra of Europa's atmosphere. Magnesium wa...

  8. Atmospheric contamination

    International Nuclear Information System (INIS)

    It is about the levels of contamination in center America, the population's perception on the problem, effects of the atmospheric contamination, effects in the environment, causes of the atmospheric contamination, possibilities to reduce the atmospheric contamination and list of Roeco Swisscontac in atmospheric contamination

  9. Mid-infrared Semiconductor Optoelectronics

    CERN Document Server

    Krier, Anthony

    2006-01-01

    The practical realisation of optoelectronic devices operating in the 2–10 µm (mid-infrared) wavelength range offers potential applications in a variety of areas from environmental gas monitoring around oil rigs and landfill sites to the detection of pharmaceuticals, particularly narcotics. In addition, an atmospheric transmission window exists between 3 µm and 5 µm that enables free-space optical communications, thermal imaging applications and the development of infrared measures for "homeland security". Consequently, the mid-infrared is very attractive for the development of sensitive optical sensor instrumentation. Unfortunately, the nature of the likely applications dictates stringent requirements in terms of laser operation, miniaturisation and cost that are difficult to meet. Many of the necessary improvements are linked to a better ability to fabricate and to understand the optoelectronic properties of suitable high-quality epitaxial materials and device structures. Substantial progress in these m...

  10. HF doppler sounder measurements of the ionospheric signatures of small scale ULF waves

    Science.gov (United States)

    Baddeley, L. J.; Yeoman, T. K.; Wright, D. M.

    2005-07-01

    An HF Doppler sounder, DOPE (DOppler Pulsation Experiment) with three azimuthally-separated propagation paths is used to provide the first statistical examination of small scale-sized, high m waves where a direct measurement of the azimuthal wavenumber m, is made in the ionosphere. The study presents 27 events, predominantly in the post-noon sector. The majority of events are Pc4 waves with azimuthal m numbers ranging from 100 to 200, representing some of the smallest scale waves ever observed in the ionosphere. 4 Pc5 waves are observed in the post-noon sector. The fact that measurements for the wave azimuthal m number and the wave angular frequency are available allows the drift-bounce resonance condition to be used to hypothesise potential particle populations which could drive the waves through either a drift or drift-bounce resonance interaction mechanism. These results are compared with the statistical study presented by Baddeley et al. (2004) which investigated the statistical likelihood of such driving particle populations occurring in the magnetospheric ring current. The combination of these two studies indicates that any wave which requires a possible drift resonance interaction with particles of energies >60 keV, is statistically unlikely to be generated by such a mechanism. The evidence presented in this paper therefore suggests that in the pre-noon sector the drift-bounce resonance mechanism is statistically more likely implying an anti-symmetric standing wave structure while in the post-noon sector both a drift or drift-bounce resonance interaction is statistically possible, indicating both symmetric and anti-symmetric standing mode structures. A case study is also presented investigating simultaneous observations of a ULF wave in ground magnetometer and DOPE data. The event is in the lower m range of the statistical study and displays giant pulsation (Pg) characteristics. Keywords. Ionosphere (Ionosphere-magnetosphere interactions) Magnetospheric

  11. A time-domain electromagnetic sounder for detection and characterization of groundwater on Mars

    Science.gov (United States)

    Grimm, Robert E.; Berdanier, Barry; Warden, Robert; Harrer, James; Demara, Raymond; Pfeiffer, James; Blohm, Richard

    2009-09-01

    A prototype time-domain electromagnetic (TDEM) sounder was developed to technical readiness level (TRL) 5 to detect and characterize deep groundwater on Mars. The TDEM method induces eddy currents in the subsurface by abrupt extinction of a steady current in a large, flat-lying loop antenna, and the subsurface response is measured using the same loop or a separate receiver. TDEM has been widely used in terrestrial groundwater exploration and is ideally suited to sense the high electrical conductivity associated with saline groundwater expected on Mars. The inductive regime of TDEM is distinct from ground-penetrating radar: the latter has higher resolution but smaller depth of investigation. Our Mars-prototype TDEM was tested in the laboratory and at a local field site before the principal test was performed on Maui, Hawaii. This location was chosen because of its analogy to Mars in electrical properties: dry, resistive basalt over saline pore water. Results compared favorably to soundings made with a commercial TDEM, clearly detecting the seawater interface at depths of 250 m. We subsequently developed a ballistic deployment system for the loop antenna suitable for robotic missions. Compressed gas launches two projectiles; each consists of two spools on a guide stick. Payout on one spool is back towards the launcher and on the other toward its twin on the other projectile. In this way a triangular loop antenna is formed. The full system was tested twice, successfully achieving a distance of ˜70 m in both. A system capable of deploying a 200 m loop antenna on Mars would have mass <6 kg (including 0.3 kg electronics) and within one sol could detect groundwater at depths up to 5 km. TDEM can probe to depths not possible for radar and answer the question: does groundwater - and a likely subsurface habitable zone - exist on Mars?

  12. Ex situ echo sounder target strengths of ice krill Euphausia crystallorophias

    Science.gov (United States)

    La, Hyoung Sul; Lee, Hyungbeen; Kang, Donhyug; Lee, SangHoon; Shin, Hyoung Chul

    2015-05-01

    Ice krill is the keystone species in the neritic ecosystem in the Southern Ocean, where it replaces the more oceanic Antarctic krill. It is essential to understand the variation of target strength (TS in dB re 1 m2) with the different body size to accurately estimate ice krill stocks. However, there is comparatively little knowledge of the acoustic backscatter of ice krill. The TS of individual, formalin-preserved, tethered ice krill was measured in a freshwater test tank at 38, 120, and 200 kHz with a calibrated split-beam echo sounder system. Mean TS was obtained from 21 individual ice krill with a broad range of body lengths ( L: 13-36 mm). The length ( L, mm) to wet weight ( W; mg) relationship for ice krill was W=0.001218×103 × L 3.53 ( R 2 =0.96). The mean TS-to-length relationship were TS38 kHz =-177.4+57log10 ( L), ( R 2 = 0.86); TS120 kHz = -129.9+31.56log10 ( L), ( R 2 =0.87); and TS200 kHz =-117.6+24.66log10 ( L), ( R 2 =0.84). Empirical estimates of the relationship between the TS and body length of ice krill were established at 38, 120, and 200 kHz and compared with predictions obtained from both the linear regression model of Greene et al. (1991) and the Stochastic Distorted Wave Born Approximation (SDWBA) model. This result might be applied to improve acoustic detection and density estimation of ice krill in the Southern Ocean. Further comparative studies are needed with in situ target strength including various body lengths of ice krill.

  13. Land and Atmosphere Near-Real-Time Capability for Earth Observing System

    Science.gov (United States)

    Murphy, Kevin J.

    2011-01-01

    LANCE (Land, Atmosphere Near-Real-Time Capability for EOS) in 2009. LANCE consists of special processing elements, co-located with selected EOSDIS data centers and processing facilities. A primary goal of LANCE is to bring multiple near-real-time systems under one umbrella, offering commonality in data access, quality control, and latency. LANCE now processes and distributes data from the Moderate Resolution Imaging Spectroradiometer (MODIS), Atmospheric Infrared Sounder (AIRS), Advanced Microwave Scanning Radiometer Earth Observing System (AMSR-E), Microwave Limb Sounder (MLS) and Ozone Monitoring Instrument (OMI) instruments within 3 hours of satellite observation. The Rapid Response System and the Fire Information for Resource Management System (FIRMS) capabilities will be incorporated into LANCE in 2011. LANCE maintains a central website to facilitate easy access to data and user services. LANCE products are extensively tested and compared with science products before being made available to users. Each element also plans to implement redundant network, power and server infrastructure to ensure high availability of data and services. Through the user registration system, users are informed of any data outages and when new products or services will be available for access. Building on a significant investment by NASA in developing science algorithms and products, LANCE creates products that have a demonstrated utility for applications requiring near-real-time data. From lower level data products such as calibrated geolocated radiances to higher-level products such as sea ice extent, snow cover, and cloud cover, users have integrated LANCE data into forecast models and decision support systems. The table above shows the current near-real-time product categories by instrument. The ESDIS Project continues to improve the LANCE system and use the experience gained through practice to seek adjustments to improve the quality and performance of the system. For example, an

  14. [Infrared erythema].

    Science.gov (United States)

    Schulze, H J; Schmidt, R; Mahrle, G

    1985-06-15

    This article deals with the immediate effect of infra-red (IR) irradiation on human skin. The cutaneous response to IR significantly differed from that to polychromatic UV rays. The IR erythema showed a reticular pattern and was monophasic. Minimal erythema (ME) appeared without latency and faded a few minutes later. Induction of IR-ME required a radiation doses about 15,000 times higher (187-295 J/m2) than was needed for UVB erythema. The maximum erythema also occurred immediately after exposure to IR and faded away within one to four hours. The response was biphasic in only one of 28 test persons. Histological studies revealed dilated vessels and perivascular accumulation of degranulated mast cells. PMID:4024676

  15. Data on atmospheric transmission in the IR spectral region

    Science.gov (United States)

    Paramonova, N. N.; Kazakova, K. V.; Brounshteyn, A. M.

    1979-01-01

    The weakening of radiation by the atmosphere in the infrared region of the spectrum was studied. The instrument used for the measurements was the IKAU-1 infrared atmospheric unit, and measurements were carried out both on an inclined path and a near-earth horizontal path.

  16. Impact of atmospheric water vapor on the thermal infrared remote sensing of volcanic sufur dioxide emmisions: A case study from Pu'u 'O'o vent of Kilauea volcano, Hawaii

    Science.gov (United States)

    Realmuto, V. J.; Worden, H. M.

    2000-01-01

    The December 18, 1999, launch of NASA's Terra satellite put two multispectral thermal infrared imaging instruments into Earth orbit. Experiments with airborne instruments have demonstrated that the data from such instruments can be used to detect volcanic SO2 plumes and clouds.

  17. Two classes of medium-scale traveling ionospheric disturbances observed with an array on HF-Doppler sounders

    International Nuclear Information System (INIS)

    The importance of the quasi-evanescent mode of acoustic-gravity waves (AGW) was recently stressed to elaborate on the daytime dispersion characteristics of horizontal velocity of medium-scale traveling ionospheric disturbances (MS-TID) which were observed by a high frequency Doppler (HFD) sounder array in central Japan. Observed MS-TIDs were classified into two categories: the internal mode and the quasi-evanescent mode as regards physical implication. Nonlinear wave-wave interaction is proposed in an attempt to explain salient features of the latter-class TID

  18. Two classes of medium-scale traveling ionospheric disturbances observed with an array on HF-Doppler sounders

    Science.gov (United States)

    Shibata, T.; Okuzawa, T.

    1985-01-01

    The importance of the quasi-evanescent mode of acoustic-gravity waves (AGW) was recently stressed to elaborate on the daytime dispersion characteristics of horizontal velocity of medium-scale traveling ionospheric disturbances (MS-TID) which were observed by a high frequency Doppler (HFD) sounder array in central Japan. Observed MS-TIDs were classified into two categories: the internal mode and the quasi-evanescent mode as regards physical implication. Nonlinear wave-wave interaction is proposed in an attempt to explain salient features of the latter-class TID.

  19. Long-distance HF propagation modes deduced from the simultaneous observation by chirp sounder and ISS-b

    Science.gov (United States)

    Ichinose, M.; Fujii, S.; Nozaki, K.; Igi, S.

    1982-06-01

    Chirp oblique sounding data and ionospheric data gathered by the ISS-b satellite were analyzed to characterize the propagation modes between West Germany and Japan. Hourly ionograms were generated from November 1978 to May 1979 using chirp sounder operating in the 4-30 MHz range, and ionospheric conditions were measured each time the ISS-b orbit crossed the circuit. Propagation times were quantified for each frequency step by entering the measured ionosphere parameters into a parabolic model for the F2 layer. Simulations were performed for 3- to 5-hop propagation modes and compared with empirical data, showing that the MOF exceeds a theoretical MUF by 1 MHz.

  20. Infrared Astronomy

    Science.gov (United States)

    Mampaso, A.; Prieto, M.; Sánchez, F.

    2004-01-01

    What do we understand of the birth and death of stars? What is the nature of the tiny dust grains that permeate our Galaxy and other galaxies? And how likely is the existence of brown dwarfs, extrasolar planets or other sub-stellar mass objects? These are just a few of the questions that can now be addressed in a new era of infrared observations. IR astronomy has been revolutionised over the past few years by the widespread availability of large, very sensitive IR arrays and the success of IR satellites (IRAS in particular). Several IR space missions due for launch over the next few years promise an exciting future too. For these reasons, the IV Canary Islands Winter School of Astrophysics was dedicated to this burgeoning field. Its primary goal was to introduce graduate students and researchers from other areas to the important new observations and physical ideas that are emerging in this wide-ranging field of research. Lectures from nine leading researchers, renowned for their teaching abilities, are gathered in this volume. These nine chapters provide an excellent introduction as well as a thorough and up-to-date review of developments - essential reading for graduate students entering IR astronomy, and professionals from other areas who realise the importance that IR astronomy may have on their research.

  1. Greenhouse effect in the atmosphere

    Science.gov (United States)

    Smirnov, B. M.

    2016-04-01

    Average optical atmospheric parameters for the infrared spectrum range are evaluated on the basis of the Earth energetic balance and parameters of the standard atmosphere. The average optical thickness of the atmosphere is u ≈ 2.5 and this atmospheric emission is originated at altitudes below 10 km. Variations of atmospheric radiative fluxes towards the Earth and outward are calculated as a function of the concentration of \\text{CO}2 molecules for the regular model of molecular spectrum. As a result of doubling of the \\text{CO}2 concentration the change of the global Earth temperature is (0.4 +/- 0.2) \\text{K} if other atmospheric parameters are conserved compared to the value (3.0 +/- 1.5) \\text{K} under real atmospheric conditions with the variation of the amount of atmospheric water. An observed variation of the global Earth temperature during the last century (0.8 ^\\circ \\text{C}) follows from an increase of the mass of atmospheric water by 7% or by conversion of 1% of atmospheric water in aerosols.

  2. HF doppler sounder measurements of the ionospheric signatures of small scale ULF waves

    Directory of Open Access Journals (Sweden)

    L. J. Baddeley

    2005-07-01

    Full Text Available An HF Doppler sounder, DOPE (DOppler Pulsation Experiment with three azimuthally-separated propagation paths is used to provide the first statistical examination of small scale-sized, high m waves where a direct measurement of the azimuthal wavenumber m, is made in the ionosphere. The study presents 27 events, predominantly in the post-noon sector. The majority of events are Pc4 waves with azimuthal m numbers ranging from –100 to –200, representing some of the smallest scale waves ever observed in the ionosphere. 4 Pc5 waves are observed in the post-noon sector. The fact that measurements for the wave azimuthal m number and the wave angular frequency are available allows the drift-bounce resonance condition to be used to hypothesise potential particle populations which could drive the waves through either a drift or drift-bounce resonance interaction mechanism. These results are compared with the statistical study presented by Baddeley et al. (2004 which investigated the statistical likelihood of such driving particle populations occurring in the magnetospheric ring current. The combination of these two studies indicates that any wave which requires a possible drift resonance interaction with particles of energies >60 keV, is statistically unlikely to be generated by such a mechanism. The evidence presented in this paper therefore suggests that in the pre-noon sector the drift-bounce resonance mechanism is statistically more likely implying an anti-symmetric standing wave structure while in the post-noon sector both a drift or drift-bounce resonance interaction is statistically possible, indicating both symmetric and anti-symmetric standing mode structures. A case study is also presented investigating simultaneous observations of a ULF wave in ground magnetometer and DOPE data. The event is in the lower m range of the statistical study and displays giant pulsation (Pg characteristics.

    Keywords

  3. Calibration and brightness temperature algorithm of CE-1 Lunar Microwave Sounder (CELMS)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    CE-1 Lunar Microwave Sounder (CELMS) is the first passive microwave radiometer in the world to sound the surface of the Moon in the lunar orbit at altitude of 200 km. The scientific objective of CELMS is to obtain global brightness temperature (TB) of the Moon, to retrieve information on lunar regolith, and to evaluate the distribution of helium-3 on the Moon implanted by solar wind. Before launch of CELMS, a series of experiments were carried out in laboratories to test the performances of the systems, and to calibrate the responses between the input of TB and the output of voltage from the receivers. However, the thermal condition exposed to CELMS is more complicated in lunar orbit than on the Earth, which makes the temperatures of different parts of CELMS wave vary greatly, and the cosmic background is not very clean due to the pointing of cold space antenna to the direction of the satellite running, which brings uncertainties into data-processing of CELMS when the temperature of cold space is used as a calibrator. Furthermore, the lack of knowledge on the lunar ingredients and compositions, distributions of physical temperatures, and properties on lunar microwave radiation leads to difficulties in validating the measurements and retrievals of CELMS. By analyzing the results of ground experiments and the measurements of CELMS in-orbit, along with our knowledge of the properties of lunar surface, here we give algorithms on calibration and antenna pattern correction (APC) of CELMS. We also describe in detail the principle of microwave transfer among the elements of CELMS, and discuss the method on testing calibration parameters of the system. In addition, the theory and model on correction antenna pattern of CELMS are developed by comparing antenna temperatures by CELMS with those simulated by microwave radiative transfer models. The global distribution of TB is given and the features of TB are analyzed. Our results show rich information included in TB on the

  4. Rossby-wave driven stirring of the UTLS - a detailed view on the intricately layered structure by the 3-D imaging limb-sounder GLORIA

    Science.gov (United States)

    Ungermann, J.; Friedl-Vallon, F.; Hoepfner, M.; Oelhaf, H.; Preusse, P.; Riese, M.

    2014-12-01

    The Gimballed Limb Radiance Imager of the Atmosphere (GLORIA) is a new instrument that combines a classical Fourier transform spectrometer (FTS) with a 2-D detector array. Imaging allows the spatial sampling to be improved by up to an order of magnitude when compared to a limb scanning instrument. GLORIA is designed to operate on various high altitude research platforms. The instrument is a joint development of the German Helmholtz Large Research Facilities Karlsruhe Institute of Technology (KIT) and Research Centre Juelich (FZJ). GLORIA builds upon the heritage of KIT and FZJ in developing and operating IR limb sounders (MIPAS, CRISTA). In Summer 2012, GLORIA was an integral part of the first large missions for the German research aircraft HALO dedicated to