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Sample records for microwave water radiometer

  1. Monolithic microwave integrated circuit water vapor radiometer

    NASA Technical Reports Server (NTRS)

    Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

    1991-01-01

    A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

  2. Microwave Radiometer (MWR) Handbook

    SciTech Connect

    Morris, VR

    2006-08-01

    The Microwave Radiometer (MWR) provides time-series measurements of column-integrated amounts of water vapor and liquid water. The instrument itself is essentially a sensitive microwave receiver. That is, it is tuned to measure the microwave emissions of the vapor and liquid water molecules in the atmosphere at specific frequencies.

  3. Atmospheric water distribution in cyclones as seen with Scanning Multichannel Microwave Radiometers (SMMR)

    NASA Technical Reports Server (NTRS)

    Katsaros, K. B.; Mcmurdie, L. A.

    1983-01-01

    Passive microwave measurements are used to study the distribution of atmospheric water in midlatitude cyclones. The integrated water vapor, integrated liquid water, and rainfall rate are deduced from the brightness temperatures at microwave frequencies measured by the Scanning Multichannel Microwave Radiometer (SMRR) flown on both the Seasat and Nimbus 7 satellites. The practical application of locating fronts by the cyclone moisture pattern over oceans is shown, and the relationship between the quantity of coastal rainfall and atmospheric water content is explored.

  4. Using Multiple Instrument Measurements To Assess Integrated Water Vapor Path From A Multispectral Microwave Radiometer

    NASA Astrophysics Data System (ADS)

    Fallon, J.; Han, Z. T.; Gross, B.; Moshary, F.

    2013-12-01

    Microwave Radiometers are mounted on satellites and the ground to collect climatological data. While they provide very useful information about temperature, RH, and water vapor, radiometers should periodically be cross-referenced with other instruments to gauge the veracity of the data. Data available from the closest ground-based GPS receivers and sun photometers was plotted alongside, and used to analyze, data from City College's Microwave Radiometer. Observing all of the data together in a graph allows one to see some of the general advantages and disadvantages of each instrument. The GPS-MET seems to be accurate continuously, while AERONET data is not even available during the night and while there is cloud cover. Lastly, the microwave radiometer collects data continuously, but at certain times the data are about five times higher than the expected values, based on the values given by GPS-MET and AERONET. A good explanation for those spikes is rainfall. For times when it is not raining, the microwave radiometer at City College is sufficiently close to the integrated water vapor data collected by City College's sun photometer and data from Union, New Jersey and East Moriches, New York, as proven by statistical tools.

  5. Microwave radiometer studies of atmospheric water over the oceans, volume 1

    NASA Technical Reports Server (NTRS)

    Katsaros, Kristina B.

    1992-01-01

    Since Seasat carried the Scanning Multichannel Microwave Radiometer (SMMR) into space, shortly followed by the SMMR on Nimbus 7, a new type of data source on atmospheric water vapor and other meteorological parameters has been available for analysis of weather systems over the ocean. Since 1987, the Scanning Multichannel Microwave/Imager (SMM/I) has provided similar data. A collection of work using this data is presented.

  6. Retrieval of water, ammonia and dynamics using microwave spectra: With application to Juno Microwave Radiometer

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Ingersoll, Andrew P.; Janssen, Michael A.

    2016-10-01

    The Juno Microwave Radiometer (MWR) is designed to measure the thermal emission of Jupiter's atmosphere from the cloud tops at about 1 bar pressure to as deep as hundreds of bars pressure, with unprecedented accuracy and spatial resolution. Unlike infrared spectroscopy, microwave observations of giant planetary atmospheres are difficult to interpret due to the absence of spectral features and broad weighting functions. The observed quantity is an intricate consequence of thermodynamic and dynamic processes. To unravel the mystery, we introduce two scalar parameters (stretching and cooling) that describe the alteration of the atmospheric thermal and compositional structure by dynamics. Using the above parameters, we are able to fit the Galileo Probe results as well as model the spectral differences between hot spots, zones and belts in Jupiter's atmosphere observed by VLA (de Pater et al., 2016). Finally, we make use of the state-of-the-art retrieval method - Markov Chain Monte Carlo - to determine the joint probability distribution of all parameters of interest. This approach fully calibrates error, assesses covariance between parameters, and explores the widest possible types of atmospheric conditions as opposed to traditional trial-and-error method. We apply this method to simulated Juno/MWR observations. We show that the water abundance is constrained to +3.1/-1.5 times solar for a normal situation and is constrained to an upper limit for an extreme situation.

  7. Microwave radiometer studies of atmospheric water over the oceans, volume 2

    NASA Technical Reports Server (NTRS)

    Katsaros, Kristina B.

    1992-01-01

    Since the Seasat carried the Scanning Multichannel Microwave Radiometer (SMMR) into space in July of 1978, shortly followed by the SMMR on Nimbus 7, which operated for almost a decade, a new type of data source on atmospheric water vapor and other meteorological parameters has been available for analysis of weather systems over the ocean. Since 1987, we have had the Scanning Multichannel Microwave/Imager (SSM/I) instrument on Defense Meteorological Satellites providing similar data. We present a collection of our work performed over the last years of the study.

  8. A multifrequency microwave radiometer of the future

    NASA Technical Reports Server (NTRS)

    Le Vine, D.; Wilheit, T.; Murphy, R.; Swift, C.

    1987-01-01

    The design of the High-Resolution Multifrequency Microwave Radiometer (HMMR), which is to be installed on EOS, is described. The HMMR is to consist of the Advanced Microwave Sounding Unit (AMSU), the Advanced Mechanically Scanned Radiometer (AMSR), and the Electronically Scanned Thinned Array Radiometer (ESTAR). The AMSU is a 20-channel microwave radiometer system designed to measure profiles of atmospheric temperature and humidity and the AMSR is a microwave imager with channels at 6, 10, 18, 21, 37, and 90 GHz for measuring snow cover over land, the age and areal extent of sea ice, the intensity of precipitation over oceans and land, and the amount of water in the atmosphere. ESTAR is an imaging radiometer operating near 1.4 GHz capable of obtaining global maps of surface soil moisture with a spatial resolution of about 10 km. The antenna and signal processing utilized in the ESTAR to achieve the real aperture resolution are examined.

  9. Synthetic aperture microwave radiometer

    NASA Astrophysics Data System (ADS)

    Levine, D. M.

    Realizing the full potential of microwave remote sensing from space requires putting relatively large antennas in orbit. Research is being conducted to develop synthetic aperture antennas to reduce the physical collecting area required of sensors in space, and to possibly open the door to new applications of microwave remote sensing. The technique under investigation involves using a correlation interferometer with multiple baselines. The Microwave Sensors and Data Collection Branch has been engaged in research to develop this technique for applications to remote sensing of soil moisture from space. Soil moisture is important for agricultural applications and for understanding the global hydrologic cycle. An aircraft prototype of an instrument suitable for making such measurements was developed. This is an L-band radiometer called ESTAR which is hoped will become part of the Earth Observing System (EOS). ESTAR is a hybrid instrument which uses both real aperture antennas (long sticks to obtain resolution in the along-track dimension) and aperture synthesis (correlation between sticks to obtain resolution in the cross track dimension). The hybrid was chosen as a compromise to increase the sensitivity (T) of the instrument.

  10. Water vapour profiles from Raman lidar automatically calibrated by microwave radiometer data during HOPE

    NASA Astrophysics Data System (ADS)

    Foth, A.; Baars, H.; Di Girolamo, P.; Pospichal, B.

    2015-07-01

    In this paper, we present a method to derive water vapour profiles from Raman lidar measurements calibrated by the integrated water vapour (IWV) from a collocated microwave radiometer during the intense observation campaign HOPE in the frame of the HD(CP)2 initiative. The simultaneous observation of a microwave radiometer and a Raman lidar allowed an operational and continuous measurement of water vapour profiles also during cloudy conditions. The calibration method provides results which are in a good agreement with conventional methods based on radiosondes. The calibration factor derived from the proposed IWV method is very stable with a relative uncertainty of 5 %. This stability allows for the calibration of the lidar even in the presence of clouds using the calibration factor determined during the most recent clear sky interval. Based on the application of this approach, it is possible to retrieve water vapour profiles during all non-precipitating conditions. A statistical analysis shows a good agreement between the lidar measurements and collocated radiosondes. The relative biases amount to less than 6.7 % below 2 km.

  11. Water vapour profiles from Raman lidar automatically calibrated by microwave radiometer data during HOPE

    NASA Astrophysics Data System (ADS)

    Foth, A.; Baars, H.; Di Girolamo, P.; Pospichal, B.

    2015-03-01

    In this paper, we present a method to derive water vapour profiles from Raman lidar measurements calibrated by the integrated water vapour (IWV) from a collocated microwave radiometer during the intense observation campaign HOPE in the frame of the HD(CP)2 initiative. The simultaneous observation of a microwave radiometer and a Raman lidar allowed an operational and continuous measurement of water vapour profiles also during cloudy conditions. The calibration method provides results in a good agreement with conventional methods based on radiosondes. The calibration factor derived from the proposed IWV method is very stable with a relative uncertainty of 6%. This stability allows to calibrate the lidar even in the presence of clouds using the calibration factor determined during the closest in time clear sky interval. Based on the application of this approach, it is possible to retrieve water vapour profiles during all non-precipitating conditions. A statistical analysis shows a good agreement between the lidar measurements and collocated radiosondes. The relative biases amount to less than 6.7% below 2 km.

  12. Water Vapor and Wet Tropospheric Path Delay estimation from HY-2A Calibration Microwave Radiometer

    NASA Astrophysics Data System (ADS)

    Yang, J.; Zheng, G.; Ren, L.

    2016-12-01

    The data of Jason-1 microwave radiometer (JMR) and Jason-2 advanced microwave radiometer (AMR) are used as reference for the development and validation of retrieval models of water vapor (WV) and wet tropospheric path delay (PD) for the calibration microwave radiometer (CMR) on board the first ocean dynamic environment satellite of China—Haiyang-2A (HY-2A). The crossover points of the HY-2A and Jason-1/2 satellite tracks are extracted, and the data pairs at these points are divided into fitting and validation datasets. The retrieval models of WV and PD are built for the CMR using the fitting dataset and genetic algorithm, and validated using the validation dataset. The validation shows that the results of the retrieval models are consistent with the JMR and AMR data, and the root-mean-square differences of WV and PD are 1.86 kgm-2 and 11.4mm, respectively. Finally, the retrieved results from the CMR brightness temperature along-track data using the retrieval models and the AMR along-track data are gridded by the inverse distance weighted method. Their monthly-mean spatial distributions are compared in order to investigate the applicability of the retrieval models globally, namely, beyond locations of the data pairs in the validation dataset. The comparison shows that the retrieval models are applicable in most open ocean areas, and that the latitude and temporal inhomogeneity of the crossover point distribution in the fitting dataset does not lead to obvious latitude and temporal inhomogeneity in the gridded data.

  13. Wideband Agile Digital Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Gaier, Todd C.; Brown, Shannon T.; Ruf, Christopher; Gross, Steven

    2012-01-01

    The objectives of this work were to take the initial steps needed to develop a field programmable gate array (FPGA)- based wideband digital radiometer backend (>500 MHz bandwidth) that will enable passive microwave observations with minimal performance degradation in a radiofrequency-interference (RFI)-rich environment. As manmade RF emissions increase over time and fill more of the microwave spectrum, microwave radiometer science applications will be increasingly impacted in a negative way, and the current generation of spaceborne microwave radiometers that use broadband analog back ends will become severely compromised or unusable over an increasing fraction of time on orbit. There is a need to develop a digital radiometer back end that, for each observation period, uses digital signal processing (DSP) algorithms to identify the maximum amount of RFI-free spectrum across the radiometer band to preserve bandwidth to minimize radiometer noise (which is inversely related to the bandwidth). Ultimately, the objective is to incorporate all processing necessary in the back end to take contaminated input spectra and produce a single output value free of manmade signals to minimize data rates for spaceborne radiometer missions. But, to meet these objectives, several intermediate processing algorithms had to be developed, and their performance characterized relative to typical brightness temperature accuracy re quirements for current and future microwave radiometer missions, including those for measuring salinity, soil moisture, and snow pack.

  14. Observing atmospheric water in storms with the Nimbus 7 scanning multichannel microwave radiometer

    NASA Technical Reports Server (NTRS)

    Katsaros, K. B.; Lewis, R. M.

    1984-01-01

    Employing data on integrated atmospheric water vapor, total cloud liquid water and rain rate obtainable from the Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR), we study the frontal structure of several mid-latitude cyclones over the North Pacific Ocean as they approach the West Coast of North America in the winter of 1979. The fronts, analyzed with all available independent data, are consistently located at the leading edge of the strongest gradient in integrated water vapor. The cloud liquid water content, which unfortunately has received very little in situ verification, has patterns which are consistent with the structure seen in visible and infrared imagery. The rain distribution is also a good indicator of frontal location and rain amounts are generally within a factor of two of what is observed with rain gauges on the coast. Furthermore, the onset of rain on the coast can often be accurately forecast by simple advection of the SMMR observed rain areas.

  15. Measurements of integrated water vapor and cloud liquid water from microwave radiometers at the DOE ARM Cloud and Radiation Testbed in the U.S. Southern Great Plains

    SciTech Connect

    Liljegren, J.C.; Lesht, B.M.

    1996-06-01

    The operation and calibration of the ARM microwave radiometers is summarized. Measured radiometric brightness temperatures are compared with calculations based on the model using co-located radiosondes. Comparisons of perceptible water vapor retrieved from the radiometer with integrated soundings and co-located GPS retrievals are presented. The three water vapor sensing systems are shown to agree to within about 1 mm.

  16. Water vapour variability during Indian monsoon over Trivandrum observed using Microwave Radiometer and GPS

    NASA Astrophysics Data System (ADS)

    Raju, Suresh C.; Krishna Moorthy, K.; Ramachandran Pillai, Renju; Uma, K. N.; Saha, Korak

    2012-07-01

    The Indian summer monsoon is a highly regular synoptic event, providing most of the annual rainfall received over the sub-continent. Trivandrum, at the southwestern tip of Indian peninsula, is considered as the gate way of Indian monsoon, with its climatological onset on June 01. During this season, the region, experiences large seasonal variation in water vapor, rain fall and wind (speed and direction) in the troposphere. The variability in water vapor and wind information are the vital parameters in forecasting the onset of monsoon. This study focuses on water vapor measurements over the tropical coastal station Trivandrum (8.5oN & 76.9oE) using microwave techniques and the analyses with an effort to link the seasonal variability of water vapor with the onset of monsoon. At Trivandrum a hyper-spectral microwave radiometer profiler (MRP) and a Triple-frequency global positioning system receiver (GPS) have been in regular operation since April 2010. A station-dependent simple empirical relation suitable for the equatorial atmospheric condition is formulated to map the nonhydrostatic component of GPS tropospheric delay to the PWV, based on the columnar water vapor estimated from the multi-year daily radiosonde ascends from Trivandrum. A trained artificial neural network (ANN) with climatological atmospheric data of Trivandrum, is employed to derive the water vapor from the MRP brightness temperature measurements. The accuracy, reliability and consistency of PWV measurements over the tropical coastal station from these two independent instruments are assessed by comparing PWV derived from MRP and GPS measurements which resulted an rms deviation of <1.2mm (with correlation coefficient of ~0.98). This confirms the PWV derived over Trivandrum from microwave measurements are accurate even during the monsoon period in the presence of clouds and rain. PWV from microwave radiometer measurements for more than two years are used to study the water vapour variability during

  17. Observations of water vapor by ground-based microwave radiometers and Raman lidar

    NASA Technical Reports Server (NTRS)

    Han, Yong; Snider, J. B.; Westwater, E. R.; Melfi, S. H.; Ferrare, R. A.

    1994-01-01

    In November to December 1991, a substantial number of remote sensors and in situ instruments were operated together in Coffeyville, Kansas, during the climate experiment First ISCCP Regional Experiment Phase 2 (FIRE 2). Includede in the suite of instruments were (1) the NOAA Environmental Technology Laboratory (ETL) three-channel microwave radiometer, (2) the NASA GSFC Raman lidar, (3) ETL radio acoustic sounding system (RASS), and (4) frequent, research-quality radiosondes. The Raman lidar operated only at night and the focus of this portion of the experiment concentrated on clear conditions. The lidar data, together with frequent radiosondes and measurements of temperature profiles (every 15 min) by RASS allowed profiles of temperature and absolute humidity to be estimated every minute. We compared 20 min measurements of brightness temperature (T(sub b) with calculations of T(sub b) that were based on the Liebe and Layton (1987) and Liebe et al. (1993) microwave propagation models, as well as the Waters (1976) model. The comparisons showed the best agreement at 20.6 GHz with the Waters model, with the Liebe et al. (1993) model being best at 31.65 GHz. The results at 90 GHz gave about equal success with the Liebe and Layton (1987) and Liebe et al. (1993) models. Comparisons of precipitable water vapor derived independently from the two instruments also showed excellent agreement, even for averages as short as 2 min. The rms difference between Raman and radiometric determinations of precipitable water vapor was 0.03 cm which is roughly 2%. The experiments clearly demonstrate the potential of simultaneous operation of radiometers and Raman lidars for fundamental physical studies of water vapor.

  18. Optimal estimation of water vapour profiles using a combination of Raman lidar and microwave radiometer

    NASA Astrophysics Data System (ADS)

    Foth, Andreas; Pospichal, Bernhard

    2017-09-01

    In this work, a two-step algorithm to obtain water vapour profiles from a combination of Raman lidar and microwave radiometer is presented. Both instruments were applied during an intensive 2-month measurement campaign (HOPE) close to Jülich, western Germany, during spring 2013. To retrieve reliable water vapour information from inside or above the cloud a two-step algorithm is applied. The first step is a Kalman filter that extends the profiles, truncated at cloud base, to the full height range (up to 10 km) by combining previous information and current measurement. Then the complete water vapour profile serves as input to the one-dimensional variational (1D-VAR) method, also known as optimal estimation. A forward model simulates the brightness temperatures which would be observed by the microwave radiometer for the given atmospheric state. The profile is iteratively modified according to its error bars until the modelled and the actually measured brightness temperatures sufficiently agree. The functionality of the retrieval is presented in detail by means of case studies under different conditions. A statistical analysis shows that the availability of Raman lidar data (night) improves the accuracy of the profiles even under cloudy conditions. During the day, the absence of lidar data results in larger differences in comparison to reference radiosondes. The data availability of the full-height water vapour lidar profiles of 17 % during the 2-month campaign is significantly enhanced to 60 % by applying the retrieval. The bias with respect to radiosonde and the retrieved a posteriori uncertainty of the retrieved profiles clearly show that the application of the Kalman filter considerably improves the accuracy and quality of the retrieved mixing ratio profiles.

  19. A comparative study of microwave radiometer observations over snowfields with radiative transfer model calculations. [for water runoff estimation

    NASA Technical Reports Server (NTRS)

    Chang, A. T. C.; Shiue, J. C.

    1979-01-01

    Truck mounted microwave instrumentation was used to study the microwave emission characteristics of the Colorado Rocky Mountain snowpack in the vicinity of Fraser, Colorado during the winter of 1978. The spectral signatures of 5.0, 10.7, 18, and 37 GHz radiometers with dual polarization were used to measure the snowpack density and temperature profiles, rain profile, and free water content. These data were compared with calculated results based on microscopic scattering models for dry, surface melting, and very wet snowpacks.

  20. Inference of sea surface temperature, near surface wind, and atmospheric water by Fourier analysis of Scanning Multichannel Microwave Radiometer data

    NASA Technical Reports Server (NTRS)

    Rosenkranz, P. W.

    1981-01-01

    The Scanning Multichannel Microwave Radiometer measures thermal microwave emission from the earth in both polarizations at wavelengths of 0.8, 1.4, 1.7, 2.8 and 4.6 cm. Similar instruments were launched on Nimbus 7 and Seasat. Both spatial resolution on the earth and relative sensitivity to different geophysical parameters change with wavelength. Therefore, spatial Fourier components of geophysical parameters are inferred from the corresponding Fourier components of the radiometer measurements, taking into account the different dependence of signal-to-noise ratio on spatial frequency for each radiometer wavelength. The geophysical parameters are sea surface temperature, near-surface wind speed, integrated water vapor mass, integrated liquid water mass, and the product of rainfall rate with height of the rain layer. The capabilities and limitations of the inversion method are illustrated by means of data from the North Atlantic and from tropical storms.

  1. Comparisons of line-of-sight water vapor observations using the global positioning system and a pointing microwave radiometer.

    SciTech Connect

    Braun, J.; Rocken, C.; Liljegren, J. C.; Environmental Research; Univ. Corporation for Atmospheric Research

    2003-05-01

    Line-of-sight measurements of integrated water vapor from a global positioning system (GPS) receiver and a microwave radiometer are compared. These two instruments were collocated at the central facility of the Department of Energy's Atmospheric Radiation Measurement Program's Southern Great Plains region, near Lamont, Oklahoma. The comparison was made using 47 days of observations in May and June of 2000. Weather conditions during this time period were variable with total integrated water vapor ranging from less than 10 to more than 50 mm. To minimize errors in the microwave radiometer observations, observations were compared during conditions when the liquid water measured by the radiometer was less than 0.1 mm. The linear correlation of the observations between the two instruments is 0.99 with a root-mean-square difference of the GPS water vapor to a linear fit of the microwave radiometer of 1.3 mm. The results from these comparisons are used to evaluate the ability of networks of GPS receivers to measure instantaneous line-of-sight integrals of water vapor. A discussion and analysis is provided regarding the additional information of the water vapor field contained in these observations compared to time- and space-averaged zenith and gradient measurements.

  2. Salinity surveys using an airborne microwave radiometer

    NASA Technical Reports Server (NTRS)

    Paris, J. F.; Droppleman, J. D.; Evans, D. E.

    1972-01-01

    The Barnes PRT-5 infrared radiometer and L-band channel of the multifrequency microwave radiometer are used to survey the distribution of surface water temperature and salinity. These remote sensors were flown repetitively in November 1971 over the outflow of the Mississippi River into the Gulf of Mexico. Data reduction parameters were determined through the use of flight data obtained over a known water area. With these parameters, the measured infrared and microwave radiances were analyzed in terms of the surface temperature and salinity.

  3. Inter- annual variability of water vapor over an equatorial coastal station using Microwave Radiometer observations.

    NASA Astrophysics Data System (ADS)

    Renju, Ramachandran Pillai; Uma, K. N.; Krishna Moorthy, K.; Mathew, Nizy; Raju C, Suresh

    The south-western region of the Indian peninsula is the gateway of Indian summer monsoon. This region experiences continuous monsoon rain for a longer period of about six months from June to November. The amount of water vapor variability is one of the important parameters to study the onset, active and break phases of the monsoon. Keeping this in view, a multi-frequency Microwave Radiometer Profiler (MRP) has been made operational for continuous measurements of water vapor over an equatorial coastal station Thiruvananthapuram (8.5(°) N, 76.9(°) E) since April 2010. The MRP estimated precipitable water vapor (PWV) for different seasons including monsoon periods have been evaluated by comparing with the collocated GPS derived water vapor and radiosonde measurements. The diurnal, seasonal and inter annual variation of water vapor has been studied for the last four years (2010-2013) over this station. The significant diurnal variability of water vapor is found only during the winter and pre-monsoon periods (Dec -April). The vertical distribution of water vapour is studied in order to understand its variability especially during the onset of monsoon. During the building up of south-west monsoon, the specific humidity increases to ˜ 10g/kg in the altitude range of 4-6 km and consistently maintained it throughout the active spells and reduces to below 2g/kg during break spells of monsoon. The instrument details and the results will be presented.

  4. MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Datasets

    SciTech Connect

    KL Gaustad; DD Turner

    2007-09-30

    This report provides a short description of the Atmospheric Radiation Measurement (ARM) microwave radiometer (MWR) RETrievel (MWRRET) Value-Added Product (VAP) algorithm. This algorithm utilizes complimentary physical and statistical retrieval methods and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).

  5. Atmospheric water distribution in a midlatitude cyclone observed by the Seasat Scanning Multichannel Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Mcmurdie, L. A.; Katsaros, K. B.

    1985-01-01

    Patterns in the horizontal distribution of integrated water vapor, integrated liquid water and rainfall rate derived from the Seasat Scanning Multichannel Microwave Radiometer (SMMR) during a September 10-12, 1978 North Pacific cyclone are studied. These patterns are compared with surface analyses, ship reports, radiosonde data, and GOES-West infrared satellite imagery. The SMMR data give a unique view of the large mesoscale structure of a midlatitude cyclone. The water vapor distribution is found to have characteristic patterns related to the location of the surface fronts throughout the development of the cyclone. An example is given to illustrate that SMMR data could significantly improve frontal analysis over data-sparse oceanic regions. The distribution of integrated liquid water agrees qualitatively well with corresponding cloud patterns in satellite imagery and appears to provide a means to distinguish where liquid water clouds exist under a cirrus shield. Ship reports of rainfall intensity agree qualitatively very well with SMMR-derived rainrates. Areas of mesoscale rainfall, on the order of 50 km x 50 km or greater are detected using SMMR derived rainrates.

  6. Two-channel microwave radiometer for observations of total column precipitable water vapor and cloud liquid water path

    SciTech Connect

    Liljegren, J.C.

    1994-01-01

    The Atmospheric Radiation Measurement (ARM) Program is focused on improving the treatment of radiation transfer in models of the atmospheric general circulation, as well as on improving parameterizations of cloud properties and formation processes in these models (USDOE, 1990). To help achieve these objectives, ARM is deploying several two-channel, microwave radiometers at the Cloud and Radiation Testbed (CART) site in Oklahoma for the purpose of obtaining long time series observations of total precipitable water vapor (PWV) and cloud liquid water path (LWP). The performance of the WVR-1100 microwave radiometer deployed by ARM at the Oklahoma CART site central facility to provide time series measurements precipitable water vapor (PWV) and liquid water path (LWP) has been presented. The instrument has proven to be durable and reliable in continuous field operation since June, 1992. The accuracy of the PWV has been demonstrated to achieve the limiting accuracy of the statistical retrieval under clear sky conditions, degrading with increasing LWP. Improvements are planned to address moisture accumulation on the Teflon window, as well as to identity the presence of clouds with LWP at or below the retrieval uncertainty.

  7. Microwave radiometer observations of interannual water vapor variability and vertical structure over a tropical station

    NASA Astrophysics Data System (ADS)

    Renju, R.; Suresh Raju, C.; Mathew, Nizy; Antony, Tinu; Krishna Moorthy, K.

    2015-05-01

    The intraseasonal and interannual characteristics and the vertical distribution of atmospheric water vapor from the tropical coastal station Thiruvananthapuram (TVM) located in the southwestern region of the Indian Peninsula are examined from continuous multiyear, multifrequency microwave radiometer profiler (MRP) measurements. The accuracy of MRP for precipitable water vapor (PWV) estimation, particularly during a prolonged monsoon period, has been demonstrated by comparing with the PWV derived from collocated GPS measurements based on regression model between PWV and GPS wet delay component which has been developed for TVM station. Large diurnal and intraseasonal variations of PWV are observed during winter and premonsoon seasons. There is large interannual PWV variability during premonsoon, owing to frequent local convection and summer thunderstorms. During monsoon period, low interannual PWV variability is attributed to the persistent wind from the ocean which brings moisture to this coastal station. However, significant interannual humidity variability is seen at 2 to 6 km altitude, which is linked to the monsoon strength over the station. Prior to monsoon onset over the station, the specific humidity increases up to 5-10 g/kg in the altitude region above 5 km and remains consistently so throughout the active spells.

  8. Understanding Microwave Radiometers

    NASA Technical Reports Server (NTRS)

    Stacey, J. M.

    1986-01-01

    Report presents principles of microwave receivers for observing planetary surfaces from space. Report is tutorial and explains operation of receivers in detail to enable reader to specify and qualify them for spaceborne operation. Gives many examples to illustrate practical design procedures.

  9. Digital signal processing in microwave radiometers

    NASA Technical Reports Server (NTRS)

    Lawrence, R. W.; Stanley, W. D.; Harrington, R. F.

    1980-01-01

    A microprocessor based digital signal processing unit has been proposed to replace analog sections of a microwave radiometer. A brief introduction to the radiometer system involved and a description of problems encountered in the use of digital techniques in radiometer design are discussed. An analysis of the digital signal processor as part of the radiometer is then presented.

  10. Biases in Total Precipitable Water Vapor Climatologies from Atmospheric Infrared Sounder and Advanced Microwave Scanning Radiometer

    NASA Technical Reports Server (NTRS)

    Fetzer, Eric J.; Lambrigtsen, Bjorn H.; Eldering, Annmarie; Aumann, Hartmut H.; Chahine, Moustafa T.

    2006-01-01

    We examine differences in total precipitable water vapor (PWV) from the Atmospheric Infrared Sounder (AIRS) and the Advanced Microwave Scanning Radiometer (AMSR-E) experiments sharing the Aqua spacecraft platform. Both systems provide estimates of PWV over water surfaces. We compare AIRS and AMSR-E PWV to constrain AIRS retrieval uncertainties as functions of AIRS retrieved infrared cloud fraction. PWV differences between the two instruments vary only weakly with infrared cloud fraction up to about 70%. Maps of AIRS-AMSR-E PWV differences vary with location and season. Observational biases, when both instruments observe identical scenes, are generally less than 5%. Exceptions are in cold air outbreaks where AIRS is biased moist by 10-20% or 10-60% (depending on retrieval processing) and at high latitudes in winter where AIRS is dry by 5-10%. Sampling biases, from different sampling characteristics of AIRS and AMSR-E, vary in sign and magnitude. AIRS sampling is dry by up to 30% in most high-latitude regions but moist by 5-15% in subtropical stratus cloud belts. Over the northwest Pacific, AIRS samples conditions more moist than AMSR-E by a much as 60%. We hypothesize that both wet and dry sampling biases are due to the effects of clouds on the AIRS retrieval methodology. The sign and magnitude of these biases depend upon the types of cloud present and on the relationship between clouds and PWV. These results for PWV imply that climatologies of height-resolved water vapor from AIRS must take into consideration local meteorological processes affecting AIRS sampling.

  11. Forward Model Studies of Water Vapor Using Scanning Microwave Radiometers, Global Positioning System, and Radiosondes during the Cloudiness Intercomparison Experiment

    SciTech Connect

    Mattioli, Vinia; Westwater, Ed R.; Gutman, S.; Morris, Victor R.

    2005-05-01

    Brightness temperatures computed from five absorption models and radiosonde observations were analyzed by comparing them with measurements from three microwave radiometers at 23.8 and 31.4 GHz. Data were obtained during the Cloudiness Inter-Comparison experiment at the U.S. Department of Energy's Atmospheric Radiation Measurement Program's (ARM) site in North-Central Oklahoma in 2003. The radiometers were calibrated using two procedures, the so-called instantaneous ?tipcal? method and an automatic self-calibration algorithm. Measurements from the radiometers were in agreement, with less than a 0.4-K difference during clear skies, when the instantaneous method was applied. Brightness temperatures from the radiometer and the radiosonde showed an agreement of less than 0.55 K when the most recent absorption models were considered. Precipitable water vapor (PWV) computed from the radiometers were also compared to the PWV derived from a Global Positioning System station that operates at the ARM site. The instruments agree to within 0.1 cm in PWV retrieval.

  12. Atmospheric absorption model for dry air and water vapor at microwave frequencies below 100 GHz derived from spaceborne radiometer observations

    NASA Astrophysics Data System (ADS)

    Wentz, Frank J.; Meissner, Thomas

    2016-05-01

    The Liebe and Rosenkranz atmospheric absorption models for dry air and water vapor below 100 GHz are refined based on an analysis of antenna temperature (TA) measurements taken by the Global Precipitation Measurement Microwave Imager (GMI) in the frequency range 10.7 to 89.0 GHz. The GMI TA measurements are compared to the TA predicted by a radiative transfer model (RTM), which incorporates both the atmospheric absorption model and a model for the emission and reflection from a rough-ocean surface. The inputs for the RTM are the geophysical retrievals of wind speed, columnar water vapor, and columnar cloud liquid water obtained from the satellite radiometer WindSat. The Liebe and Rosenkranz absorption models are adjusted to achieve consistency with the RTM. The vapor continuum is decreased by 3% to 10%, depending on vapor. To accomplish this, the foreign-broadening part is increased by 10%, and the self-broadening part is decreased by about 40% at the higher frequencies. In addition, the strength of the water vapor line is increased by 1%, and the shape of the line at low frequencies is modified. The dry air absorption is increased, with the increase being a maximum of 20% at the 89 GHz, the highest frequency considered here. The nonresonant oxygen absorption is increased by about 6%. In addition to the RTM comparisons, our results are supported by a comparison between columnar water vapor retrievals from 12 satellite microwave radiometers and GPS-retrieved water vapor values.

  13. Interferometric Synthetic Aperture Microwave Radiometers : an Overview

    NASA Technical Reports Server (NTRS)

    Colliander, Andreas; McKague, Darren

    2011-01-01

    This paper describes 1) the progress of the work of the IEEE Geoscience and Remote Sensing Society (GRSS) Instrumentation and Future Technologies Technical Committee (IFT-TC) Microwave Radiometer Working Group and 2) an overview of the development of interferometric synthetic aperture microwave radiometers as an introduction to a dedicated session.

  14. Interferometric Synthetic Aperture Microwave Radiometers : an Overview

    NASA Technical Reports Server (NTRS)

    Colliander, Andreas; McKague, Darren

    2011-01-01

    This paper describes 1) the progress of the work of the IEEE Geoscience and Remote Sensing Society (GRSS) Instrumentation and Future Technologies Technical Committee (IFT-TC) Microwave Radiometer Working Group and 2) an overview of the development of interferometric synthetic aperture microwave radiometers as an introduction to a dedicated session.

  15. Basic data requirements for microwave radiometer systems

    NASA Technical Reports Server (NTRS)

    Lawrence, R. W.

    1990-01-01

    Microwave radiometry has emerged over the last two decades to become an integral part of the field of environmental remote sensing. Numerous investigations were conducted to evaluate the use of microwave radiometry for atmospheric, oceanographic, hydrological, and geological applications. Remote sensing of the earth using microwave radiometry began in 1968 by the Soviet satellite Cosmos 243, which included four microwave radiometers (Ulably, 1981). Since then, microwave radiometers were included onboard many spacecraft, and were used to infer many physical parameters. Some of the basic concepts of radiometric emission and measurement will be discussed. Several radiometer systems are presented and an overview of their operation is discussed. From the description of the radiometer operation the data stream required from the radiometer and the general type of algorithm required for the measurement is discussed.

  16. Retrieval of Vertical Profiles of Liquid Water and Ice Content in Mixed Clouds from Doppler Radar and Microwave Radiometer Measurements.

    NASA Astrophysics Data System (ADS)

    Sauvageot, Henri

    1996-01-01

    A new method to retrieve vertical profiles of liquid water content Mw(z), ice water content Mi(z), and ice particle size distribution Ni(D, z), (where D is the ice particle size and z the vertical coordinate) in mixed nonprecipitating clouds using the observations of a zenith-viewing Doppler radar and of a microwave radiometer is proposed. In this method, the profile of the vertical air velocity deduced from Doppler radar measurements is used to describe the rate of production by the updrafts of water. vapor in excess of saturation with respect to ice. Using a Zi Mi power-law relation with an unknown linear parameter (let i, be this parameter) and initially assuming that Zw is negligible with respect to Zi, (where Zw and Zi are the radar reflectivity factors of liquid water and ice particles respectively), the measured radar reflectivity factor profile Zm ( Zi) is inverted to estimate Ni(D, z). From Ni(D, z), the profile of the rate of water vapor that can be consumed by pure deposition on ice particles is calculated. The difference between the rate of production of the exam water vapor and the rate of deposited water vapor is an expression of the rate of liquid water generation at each level. By writing that the integral of the liquid water along the profile has to be equal to the total liquid water deduced from the microwave radiometer measurement, an estimation of the i parameter is obtained. From i, an estimation of the profiles Mw(z), Mi(z), Zw(z), Zi(z) (=Zm Zw), and Ni(D, z) is calculated. If Zw is effectively negligible with respect to Zi, the computation of the retrieved profiles is ended. If not, Zi(z) is corrected and a new estimation of the profiles is computed. The results of the numerical simulation of the algorithm are presented.

  17. Comparison of atmospheric water vapour content with GNSS, Radiosonde, Microwave radiometer, and Lidar

    NASA Astrophysics Data System (ADS)

    Sohn, D.; Park, K.

    2012-12-01

    The increased amount of saturated water vapor due to the Earth's temperature rise frequently causes abnormal meteorological phenomena such as local severe rainfall in Korea. The National Institute of Meteorological Research of Korea Meteorological Administration (KMA) conducted observation experiments using a variety of water-vapor measuring equipments to improve the accuracy of weather forecasts and accurately measure the precipitable water vapor in the atmosphere. Equipments used were GNSS, water vapor radiometers (WVR), radiosonde, and LiDAR. For GNSS measurements we used two receivers that can collect not only GPS but also GLONASS signals: Trimble NetR5 and Septentrio PolaRx4. The two WVR makers are Raidometrics and RPG. For radiosonde observations, KMA launched Vaisala GPSondes every 6 hours during the experiment period. The LiDAR system was made locally by Hanbat University in Daejeon. Thus, we could obtain collocation experiment results from 6 different kinds of water vapor measurement and analyze the characteristics of each device.

  18. Advanced Microwave Radiometer (AMR) for SWOT mission

    NASA Astrophysics Data System (ADS)

    Chae, C. S.

    2015-12-01

    The objective of the SWOT (Surface Water & Ocean Topography) satellite mission is to measure wide-swath, high resolution ocean topography and terrestrial surface waters. Since main payload radar will use interferometric SAR technology, conventional microwave radiometer system which has single nadir look antenna beam (i.e., OSTM/Jason-2 AMR) is not ideally applicable for the mission for wet tropospheric delay correction. Therefore, SWOT AMR incorporates two antenna beams along cross track direction. In addition to the cross track design of the AMR radiometer, wet tropospheric error requirement is expressed in space frequency domain (in the sense of cy/km), in other words, power spectral density (PSD). Thus, instrument error allocation and design are being done in PSD which are not conventional approaches for microwave radiometer requirement allocation and design. A few of novel analyses include: 1. The effects of antenna beam size to PSD error and land/ocean contamination, 2. Receiver error allocation and the contributions of radiometric count averaging, NEDT, Gain variation, etc. 3. Effect of thermal design in the frequency domain. In the presentation, detailed AMR design and analyses results will be discussed.

  19. Increasing vertical resolution of three-dimensional atmospheric water vapor retrievals using a network of scanning compact microwave radiometers

    NASA Astrophysics Data System (ADS)

    Sahoo, Swaroop

    2011-12-01

    The thermodynamic properties of the troposphere, in particular water vapor content and temperature, change in response to physical mechanisms, including frictional drag, evaporation, transpiration, heat transfer and flow modification due to terrain. The planetary boundary layer (PBL) is characterized by a high rate of change in its thermodynamic state on time scales of typically less than one hour. Large horizontal gradients in vertical wind speed and steep vertical gradients in water vapor and temperature in the PBL are associated with high-impact weather. Observation of these gradients in the PBL with high vertical resolution and accuracy is important for improvement of weather prediction. Satellite remote sensing in the visible, infrared and microwave provide qualitative and quantitative measurements of many atmospheric properties, including cloud cover, precipitation, liquid water content and precipitable water vapor in the upper troposphere. However, the ability to characterize the thermodynamic properties of the PBL is limited by the confounding factors of ground emission in microwave channels and of cloud cover in visible and IR channels. Ground-based microwave radiometers are routinely used to measure thermodynamic profiles. The vertical resolution of such profiles retrieved from radiometric brightness temperatures depends on the number and choice of frequency channels, the scanning strategy and the accuracy of brightness temperature measurements. In the standard technique, which uses brightness temperatures from vertically pointing radiometers, the vertical resolution of the retrieved water vapor profile is similar to or larger than the altitude at which retrievals are performed. This study focuses on the improvement of the vertical resolution of water vapor retrievals by including scanning measurements at a variety of elevation angles. Elevation angle scanning increases the path length of the atmospheric emission, thus improving the signal-to-noise ratio

  20. Microwave radiometer measurement of water vapor path delay: Data reduction techniques

    NASA Technical Reports Server (NTRS)

    Claflin, E. S.; Wu, S. C.; Resch, G. M.

    1978-01-01

    Data reduction techniques are developed to compensate for water vapor path delay, a limiting error source in geodetic measurements made with very long baseline interferometry and in radio ranging to spacecraft. It is shown that water vapor path delay is proportional to a linear combination of saturation-corrected sky brightness temperatures, measured on and off the water vapor line. The effects of emission from liquid water droplets in clouds as well as most of the oxygen emission are removed by the off-line channel. Sky brightness temperatures are saturation-corrected or 'linearized' using estimates of effective sky temperatures made from surface temperature. Tipping curves are used to remove instrumental error. Coefficients are found by two methods: from a regression analysis of measured brightness temperatures versus radiosonde measured delay, and from a regression analysis of theoretical brightness temperatures versus radiosonde measured delay. In each case the coefficients are adjusted for differing climatic conditions by measurements of surface temperature, pressure, and relative humidity. Regression solutions are constrained to remove liquid water contributions and to give the correct slope for radiometer versus radiosonde path delay.

  1. Comparison of precipitable water observations in the near tropics by GPS, microwave radiometer and radiosondes.

    SciTech Connect

    Liou, Y. A.; Teng, Y. T.; VanHove, T.; Liljegren, J. C.; Environmental Research; National Central Univ.; UCAR

    2001-01-01

    The sensing of precipitable water (PW) using the Global Positioning System (GPS) in the near Tropics is investigated. GPS data acquired from the Central Weather Bureau's Taipei weather station in Banchao (Taipei), Taiwan, and each of nine International GPS Service (IGS) stations were utilized to determine independently the PW at the Taipei site from 18 to 24 March 1998. Baselines between Taipei and the other nine stations range from 676 to 3009 km. The PW determined from GPS observations for the nine baseline cases are compared with measurements by a dual-channel water vapor radiometer (WVR) and radiosondes at the Taipei site. Although previous results from other locations show that the variability in the rms difference between GPS- and WVR-observed PW ranges from 1 to 2 mm, a variability of 2.2 mm is found. The increase is consistent with scaling of the variability with the total water vapor burden (PW). In addition, accurate absolute PW estimates from GPS data for baseline lengths between 1500 and 3000 km were obtained. Previously, 500 and 2000 km have been recommended in the literature as the minimum baseline length needed for accurate absolute PW estimation. An exception occurs when GPS data acquired in Guam, one of the nine IGS stations, were utilized. This result is a possible further indication that the rms difference between GPS- and WVR-measured PW is dependent on the total water vapor burden, because both Taipei and Guam are located in more humid regions than the other stations.

  2. Electrically scanning microwave radiometer for Nimbus E

    NASA Technical Reports Server (NTRS)

    1973-01-01

    An electronically scanning microwave radiometer system has been designed, developed, and tested for measurement of meteorological, geomorphological and oceanographic parameters from NASA/GSFC's Nimbus E satellite. The system is a completely integrated radiometer designed to measure the microwave brightness temperature of the earth and its atmosphere at a microwave frequency of 19.35 GHz. Calibration and environmental testing of the system have successfully demonstrated its ability to perform accurate measurements in a satellite environment. The successful launch and data acquisition of the Nimbus 5 (formerly Nimbus E) gives further demonstration to its achievement.

  3. MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Datasets May 2009

    SciTech Connect

    Gaustad, KL; Turner, DD

    2009-05-30

    This report provides a short description of the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) microwave radiometer (MWR) RETrievel (MWRRET) value-added product (VAP) algorithm. This algorithm utilizes a complementary physical retrieval method and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).

  4. MWRRET Value-Added Product: The Retrieval of Liquid Water Path and Precipitable Water Vapor from Microwave Radiometer (MWR) Data Sets (Revision 2)

    SciTech Connect

    Gaustad, KL; Turner, DD; McFarlane, SA

    2011-07-25

    This report provides a short description of the Atmospheric Radiation Measurement (ARM) Climate Research Facility microwave radiometer (MWR) Retrieval (MWRRET) value-added product (VAP) algorithm. This algorithm utilizes a complementary physical retrieval method and applies brightness temperature offsets to reduce spurious liquid water path (LWP) bias in clear skies resulting in significantly improved precipitable water vapor (PWV) and LWP retrievals. We present a general overview of the technique, input parameters, output products, and describe data quality checks. A more complete discussion of the theory and results is given in Turner et al. (2007b).

  5. Large Antenna Multifrequency Microwave Radiometer (LAMMR) system design

    NASA Technical Reports Server (NTRS)

    King, J. L.

    1980-01-01

    The large Antenna Multifrequency Microwave Radiometer (LAMMR) is a high resolution 4 meter aperture scanning radiometer system designed to determine sea surface temperature and wind speed, atmospheric water vapor and liquid water, precipitation, and various sea ice parameters by interpreting brightness temperature images from low Earth orbiting satellites. The LAMMR with dual linear horizontal and vertical polarization radiometer channels from 1.4 to 91 GHZ can provide multidiscipline data with resolutions from 105 to 7 km. The LAMMR baseline radiometer system uses total power radiometers to achieve delta T's in the 0.5 to 1.7 K range and system calibration accuracies in the 1 to 2 deg range. A cold sky horn/ambient load two point calibration technique is used in this baseline concept and the second detector output uses an integrated and dump circuit to sample the scanning cross-tract resolution cells.

  6. Large Antenna Multifrequency Microwave Radiometer (LAMMR) system design

    NASA Astrophysics Data System (ADS)

    King, J. L.

    1980-05-01

    The large Antenna Multifrequency Microwave Radiometer (LAMMR) is a high resolution 4 meter aperture scanning radiometer system designed to determine sea surface temperature and wind speed, atmospheric water vapor and liquid water, precipitation, and various sea ice parameters by interpreting brightness temperature images from low Earth orbiting satellites. The LAMMR with dual linear horizontal and vertical polarization radiometer channels from 1.4 to 91 GHZ can provide multidiscipline data with resolutions from 105 to 7 km. The LAMMR baseline radiometer system uses total power radiometers to achieve delta T's in the 0.5 to 1.7 K range and system calibration accuracies in the 1 to 2 deg range. A cold sky horn/ambient load two point calibration technique is used in this baseline concept and the second detector output uses an integrated and dump circuit to sample the scanning cross-tract resolution cells.

  7. Digital simulation of dynamic processes in radiometer systems. [microwave radiometers

    NASA Technical Reports Server (NTRS)

    Stanley, W. D.

    1980-01-01

    The development and application of several computer programs for simulating different classes of microwave radiometers are described. The programs are dynamic in nature, and they may be used to determine the instantaneous behavior of system variables as a function of time. Some of the programs employ random variable models in the simulations so that the statistical nature of the results may be investigated. The programs have been developed to utilize either the Continuous System Modeling Program or the Advanced Continuous System Language. The validity of most of the programs was investigated using statistical tests, and the results show excellent correlation with theoretical predictions. The programs are currently being used in the investigation of new design techniques for microwave radiometers.

  8. Tomographic retrieval of cloud liquid water fields from a single scanning microwave radiometer aboard a moving platform – Part 1: Field trial results from the Wakasa Bay experiment

    SciTech Connect

    Huang, D.; Gasiewski, A.; Wiscombe, W.

    2010-07-22

    Tomographic methods offer great potential for retrieving three-dimensional spatial distributions of cloud liquid water from radiometric observations by passive microwave sensors. Fixed tomographic systems require multiple radiometers, while mobile systems can use just a single radiometer. Part 1 (this paper) examines the results from a limited cloud tomography trial with a single-radiometer airborne system carried out as part of the 2003 AMSR-E validation campaign over Wakasa Bay of the Sea of Japan. During this trial, the Polarimetric Scanning Radiometer (PSR) and Microwave Imaging Radiometer (MIR) aboard the NASA P-3 research aircraft provided a useful dataset for testing the cloud tomography method over a system of low-level clouds. We do tomographic retrievals with a constrained inversion algorithm using three configurations: PSR, MIR, and combined PSR and MIR data. The liquid water paths from the PSR retrieval are consistent with those from the MIR retrieval. The retrieved cloud field based on the combined data appears to be physically plausible and consistent with the cloud image obtained by a cloud radar. We find that some vertically-uniform clouds appear at high altitudes in the retrieved field where the radar shows clear sky. This is likely due to the sub-optimal data collection strategy. This sets the stage for Part 2 of this study that aims to define optimal data collection strategies using observation system simulation experiments.

  9. Microwave Radiometer – 3 Channel (MWR3C) Handbook

    SciTech Connect

    Cadeddu, MP

    2012-05-04

    The microwave radiometer 3-channel (MWR3C) provides time-series measurements of brightness temperatures from three channels centered at 23.834, 30, and 89 GHz. These three channels are sensitive to the presence of liquid water and precipitable water vapor.

  10. Comparison of column water vapor measurements using downward-looking near-infrared and infrared imaging systems and upward-looking microwave radiometers

    NASA Technical Reports Server (NTRS)

    Gao, Bo-Cai; Westwater, Ed R.; Stankov, B. B.; Birkenheuer, D.; Goetz, Alexander F. H.

    1992-01-01

    Remote soundings of precipitable water vapor from three systems are compared with each other and with ground truth from radiosondes. Ancillary data from a mesoscale network of surface observing stations and from wind-profiling radars are also used in the analysis. The three remote-sounding techniques are: (a) a reflectance technique using spectral data collected by the Airborne Visible-Infrared Imaging Spectrometer; (b) an emission technique using Visible-Infrared Spin Scan Radiometer Atmospheric Sounder (VAS) data acquired from the NOAA's GOES; and (c) a microwave technique using data from a limited network of three ground-based dual-channel microwave radiometers. The data were taken over the Front Range of eastern Colorado on 22-23 March 1990. The generally small differences between the three types of remote-sounding measurements are consistent with the horizontal and temporal resolutions of the instruments. The microwave and optical reflectance measurements agreed to within 0.1 cm; comparisons of the microwave data with radiosondes were also either as good or explainable. The largest differences between the VAS and the microwave radiometer at Elbert were between 0.4 and 0.5 cm and appear to be due to variable terrain within the satellite footprint.

  11. Interpretation of Integrated Water Vapor Patterns in Oceanic Midlatitude Cyclones Derived from the Scanning Multichannel Microwave Radiometer

    NASA Astrophysics Data System (ADS)

    McMurdie, Lynn Alison

    The interpretation of the integrated water vapor fields in midlatitude oceanic cyclones and how vapor patterns evolve and relate to storm intensity is the focus of this work. The integrated water vapor fields are derived from the Seasat and Nimbus 7 Scanning Multichannel Microwave Radiometers (SMMR). Averages of the typical water vapor distributions in storms occurring in specific regions and seasons are constructed. The average maximum and minimum water vapor content in storms occurring in the North Atlantic are significantly higher than in storms in the North Pacific for both warm and cold seasons. In addition, North Pacific storms have higher maximum and minimum water vapor content than Southern Ocean storms for both seasons. These differences are attributed to average differences in sea surface temperature and the amount of moisture transported poleward by the cyclones. Gridded meterological information is used to investigate the relationship between SMMR water vapor patterns and trajectories. Storms with higher than normal water vapor content have parcel trajectories that originated in low latitudes and experience significant upward motion. If a storm has an increase in water vapor with time, then the parcel trajectories at the later time originated from lower latitudes and experienced more lift than at the earlier time. A relationship between storm intensity, as defined by synoptic-scale vertical motion and surface pressure tendency, and integrated water vapor content was examined. SMMR water vapor patterns did not relate strongly to storm intensity. The usefulness of atmospheric water derived from SMMR, in the form of integrated water vapor and rainfall intensity, in indicating rapid cyclogenesis in the North Atlantic is explored. Unfortunately, unique features in the integrated water vapor patterns for storms that deepen rapidly could not be identified. However, large areas of high rain intensity are often present during the incipient stage of a rapidly

  12. Accounting For Nonlinearity In A Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Stelzried, Charles T.

    1991-01-01

    Simple mathematical technique found to account adequately for nonlinear component of response of microwave radiometer. Five prescribed temperatures measured to obtain quadratic calibration curve. Temperature assumed to vary quadratically with reading. Concept not limited to radiometric application; applicable to other measuring systems in which relationships between quantities to be determined and readings of instruments differ slightly from linearity.

  13. The microwave radiometer spacecraft: A design study

    NASA Technical Reports Server (NTRS)

    Wright, R. L. (Editor)

    1981-01-01

    A large passive microwave radiometer spacecraft with near all weather capability of monitoring soil moisture for global crop forecasting was designed. The design, emphasizing large space structures technology, characterized the mission hardware at the conceptual level in sufficient detail to identify enabling and pacing technologies. Mission and spacecraft requirements, design and structural concepts, electromagnetic concepts, and control concepts are addressed.

  14. Submarine fresh water outflow detection with a dual-frequency microwave and an infrared radiometer system

    NASA Technical Reports Server (NTRS)

    Blume, H.-J. C.; Kendall, B. M.; Fedors, J. C.

    1981-01-01

    Since infrared measurements are only very slightly affected by whitecap and banking angle influences, the combined multifrequency radiometric signatures of the L-band, the S-band, and an infrared radiometer are used in identifying freshwater outflows (submerged and superficial). To separate the river and lagoon outflows from the submarine outflows, geographical maps with a scale of 1:100,000 are used. In all, 44 submarine freshwater springs are identified. This is seen as indicating that the submarine freshwater outflow locations are more numerous around the island than had earlier been estimated. Most of the submarine springs are located at the northwest and southeast portion of the Puerto Rican coastline; the success in detecting the submarine springs during both missions at the northwest portion of the island is 39%. Salinity and temperature distribution plots along the flight path in longitude and latitude coordinates reveal that runoff direction can be determined.

  15. Submarine fresh water outflow detection with a dual-frequency microwave and an infrared radiometer system

    NASA Technical Reports Server (NTRS)

    Blume, H.-J. C.; Kendall, B. M.; Fedors, J. C.

    1981-01-01

    Since infrared measurements are only very slightly affected by whitecap and banking angle influences, the combined multifrequency radiometric signatures of the L-band, the S-band, and an infrared radiometer are used in identifying freshwater outflows (submerged and superficial). To separate the river and lagoon outflows from the submarine outflows, geographical maps with a scale of 1:100,000 are used. In all, 44 submarine freshwater springs are identified. This is seen as indicating that the submarine freshwater outflow locations are more numerous around the island than had earlier been estimated. Most of the submarine springs are located at the northwest and southeast portion of the Puerto Rican coastline; the success in detecting the submarine springs during both missions at the northwest portion of the island is 39%. Salinity and temperature distribution plots along the flight path in longitude and latitude coordinates reveal that runoff direction can be determined.

  16. Radiometer system requirements for microwave remote sensing from satellites

    NASA Technical Reports Server (NTRS)

    Juang, Jeng-Nan

    1990-01-01

    An area of increasing interest is the establishment of a significant research program in microwave remote sensing from satellites, particularly geosynchronous satellites. Due to the relatively small resolution cell sizes, a severe requirement is placed on beam efficiency specifications for the radiometer antenna. Geostationary satellite microwave radiometers could continuously monitor several important geophysical parameters over the world's oceans. These parameters include the columnar content of atmospheric liquid water (both cloud and rain) and water vapor, air temperature profiles, and possibly sea surface temperature. Two principle features of performance are of concern. The first is the ability of the radiometer system to resolve absolute temperatures with a very small absolute error, a capability that depends on radiometer system stability, on frequency bandwidth, and on footprint dwell time. The second is the ability of the radiometer to resolve changes in temperature from one resolution cell to the next when these temperatures are subject to wide variation over the overall field-of-view of the instrument. Both of these features are involved in the use of the radiometer data to construct high-resolution temperature maps with high absolute accuracy.

  17. Current status of the global change observation mission - water SHIZUKU (GCOM-W) and the advanced microwave scanning radiometer 2 (AMSR2) (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Maeda, Takashi; Kachi, Misako; Kasahara, Marehito

    2016-10-01

    Japan Aerospace Exploration Agency (JAXA) launched the Global Change Observation Mission - Water (GCOM-W) or "SHIZUKU" in 18 May 2012 (JST) from JAXA's Tanegashima Space Center. The GCOM-W satellite joins to NASA's A-train orbit since June 2012, and its observation is ongoing. The GCOM-W satellite carries the Advanced Microwave Scanning Radiometer 2 (AMSR2). The AMSR2 is a multi-frequency, total-power microwave radiometer system with dual polarization channels for all frequency bands, and successor microwave radiometer to the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) loaded on the NASA's Aqua satellite. The AMSR-E kept observation in the slower rotation speed (2 rotations per minute) for cross-calibration with AMSR2 since December 2012, its operation ended in December 2015. The AMSR2 is designed almost similarly as the AMSR-E. The AMSR2 has a conical scanning system with large-size offset parabolic antenna, a feed horn cluster to realize multi-frequency observation, and an external calibration system with two temperature standards. However, some important improvements are made. For example, the main reflector size of the AMSR2 is expanded to 2.0 m to observe the Earth's surface in higher spatial resolution, and 7.3-GHz channel is newly added to detect radio frequency interferences at 6.9 GHz. In this paper, we present a recent topic for the AMSR2 (i.e., RFI detection performances) and the current operation status of the AMSR2.

  18. Receivers for the Microwave Radiometer on Juno

    NASA Technical Reports Server (NTRS)

    Maiwald, F.; Russell, D.; Dawson, D.; Hatch, W.; Brown, S.; Oswald, J.; Janssen, M.

    2009-01-01

    Six receivers for the MicroWave Radiometer (MWR) are currently under development at JPL. These receivers cover a frequency range of 0.6 to 22 GHz in approximately octave steps, with 4 % bandwidth. For calibration and diagnosis three noise diodes and a Dicke switch are integrated into each receiver. Each receiver is connected to its own antenna which is mounted with its bore sights perpendicular to the spin axis of the spacecraft. As the spacecraft spins at 2 RPM, the antenna field of view scans Jupiter's atmosphere from limb to nadir to limb, measuring microwave emission down to 1000-bar.

  19. Null-balancing microwave radiometer

    NASA Technical Reports Server (NTRS)

    Hardy, W. N.; Love, A. W.; Jones, A. C.

    1977-01-01

    Device performs absolute temperature measurements over range of 0 to 300 degrees Kelvin. Stability of device approaches 0.1 degrees Kelvin. Potential uses include detecting oil slicks on water and determining cloud water content and water vapor content of atmosphere.

  20. Remote sensing of snowpack with microwave radiometers for hydrologic applications

    NASA Technical Reports Server (NTRS)

    Shiue, J. C.; Chang, A. T. C.; Boyne, H.; Ellerbruch, D.

    1978-01-01

    A microwave remote sensing of snowpack experiment is described and some preliminary data presented. A mobile field laboratory consisting of a four-frequency (5, 10.7, 18 and 37 GHz), all with dual linear (vertical and horizontal) polarizations, microwave radiometer system attached to a truck-mounted aerial lift was used to study the microwave emission characteristics of snowpacks in the Colorado Rocky Mountains during the winter of 1977-78. The influence of snowpack physical parameters such as water equivalent, grain size, and melt-freeze cycle on its microwave brightness temperature and its implications to the application of microwave radiometric technique to remote sensing of snowpack for runoff prediction are discussed.

  1. Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements

    NASA Astrophysics Data System (ADS)

    Sahoo, Swaroop

    Observation of profiles of temperature, humidity and winds with sufficient accuracy and fine vertical and temporal resolution are needed to improve mesoscale weather prediction, track conditions in the lower to mid-troposphere, predict winds for renewable energy, inform the public of severe weather and improve transportation safety. In comparing these thermodynamic variables, the absolute atmospheric temperature varies only by 15%; in contrast, total water vapor may change by up to 50% over several hours. In addition, numerical weather prediction (NWP) models are initialized using water vapor profile information, so improvements in their accuracy and resolution tend to improve the accuracy of NWP. Current water vapor profile observation systems are expensive and have insufficient spatial coverage to observe humidity in the lower to mid-troposphere. To address this important scientific need, the principal objective of this dissertation is to improve the accuracy, vertical resolution and revisit time of tropospheric water vapor profiles retrieved from microwave and millimeter-wave brightness temperature measurements. This dissertation advances the state of knowledge of retrieval of atmospheric water vapor from microwave brightness temperature measurements. It focuses on optimizing two information sources of interest for water vapor profile retrieval, i.e. independent measurements and background data set size. From a theoretical perspective, it determines sets of frequencies in the ranges of 20-23, 85-90 and 165-200 GHz that are optimal for water vapor retrieval from each of ground-based and airborne radiometers. The maximum number of degrees of freedom for the selected frequencies for ground-based radiometers is 5-6, while the optimum vertical resolution is 0.5 to 1.5 km. On the other hand, the maximum number of degrees of freedom for airborne radiometers is 8-9, while the optimum vertical resolution is 0.2 to 0.5 km. From an experimental perspective, brightness

  2. High-Precision Laboratory Measurements Supporting Retrieval of Water Vapor, Gaseous Ammonia, and Aqueous Ammonia Clouds with the Juno Microwave Radiometer (MWR)

    NASA Astrophysics Data System (ADS)

    Steffes, Paul G.; Hanley, Thomas R.; Karpowicz, Bryan M.; Devaraj, Kiruthika; Noorizadeh, Sahand; Duong, Danny; Chinsomboon, Garrett; Bellotti, Amadeo; Janssen, Michael A.; Bolton, Scott J.

    2016-08-01

    The NASA Juno mission includes a six-channel microwave radiometer system (MWR) operating in the 1.3-50 cm wavelength range in order to retrieve abundances of ammonia and water vapor from the microwave signature of Jupiter (see Janssen et al. 2016). In order to plan observations and accurately interpret data from such observations, over 6000 laboratory measurements of the microwave absorption properties of gaseous ammonia, water vapor, and aqueous ammonia solution have been conducted under simulated Jovian conditions using new laboratory systems capable of high-precision measurement under the extreme conditions of the deep atmosphere of Jupiter (up to 100 bars pressure and 505 K temperature). This is one of the most extensive laboratory measurement campaigns ever conducted in support of a microwave remote sensing instrument. New, more precise models for the microwave absorption from these constituents have and are being developed from these measurements. Application of these absorption properties to radiative transfer models for the six wavelengths involved will provide a valuable planning tool for observations, and will also make possible accurate retrievals of the abundance of these constituents during and after observations are conducted.

  3. Research on water ice content in Cabeus crater using the data from the microwave radiometer onboard Chang'e-1 satellite

    NASA Astrophysics Data System (ADS)

    Meng, Zhiguo; Chen, Shengbo; Osei, Edward Matthew; Wang, Zijun; Cui, Tengfei

    2010-12-01

    The existence, formation and content of water ice in the lunar permanently shaded region is one of the important questions for the current Moon study. On October 9, 2009, the LCROSS mission spacecraft impacted the Moon, and the initial result verified the existence of water on the Moon. But the study on formation and content of water ice is still under debate. The existence of water ice can change the dielectric constants of the lunar regolith, and a microwave radiometer is most sensitive to the dielectric parameters. Based on this, in this paper, the radiation transfer model is improved according to the simulation results in high frequency. Then the mixture dielectric constant models, including Odelevsky model, Wagner and landau-Lifshitz model, Clau-sius model, Gruggeman-Hanai model, etc., are analyzed and compared. The analyzing results indicate that the biggest difference occurs between Lichtenecker model and the improved Dobson model. The values estimated by refractive model are the second biggest in all the models. And the results from Odelevsky model, strong fluctuation model, Wagner and Landau -Lifshitz model, Clausius model and Bruggeman-Hanai model are very near to each other. Thereafter, the relation between volume water ice content and microwave brightness temperature is constructed with Odelevsky mixing dielectric model and the improved radiative transfer simulation, and the volume water ice content in Cabeus crater is retrieved with the data from microwave radiometer onboard Chang'e-1 satellite. The results present that the improved radiative transfer model is proper for the brightness temperature simulation of the one infinite regolith layer in high frequency. The brightness temperature in Cabeus crater is 69.93 K (37 GHz), and the corresponding volume water ice content is about 2.8%.

  4. Single-Pole Double-Throw MMIC Switches for a Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Montes, Oliver; Dawson, Douglas E.; Kangaslahti, Pekka P.

    2012-01-01

    In order to reduce the effect of gain and noise instabilities in the RF chain of a microwave radiometer, a Dicke radiometer topology is often used, as in the case of the proposed surface water and ocean topography (SWOT) radiometer instrument. For this topology, a single-pole double-throw (SPDT) microwave switch is needed, which must have low insertion loss at the radiometer channel frequencies to minimize the overall receiver noise figure. Total power radiometers are limited in accuracy due to the continuous variation in gain of the receiver. High-frequency SPDT switches were developed in the form of monolithic microwave integrated circuits (MMICs) using 75 micron indium phosphide (InP) PIN-diode technology. These switches can be easily integrated into Dicke switched radiometers that utilize microstrip technology.

  5. Preliminary development of digital signal processing in microwave radiometers

    NASA Technical Reports Server (NTRS)

    Stanley, W. D.

    1980-01-01

    Topics covered involve a number of closely related tasks including: the development of several control loop and dynamic noise model computer programs for simulating microwave radiometer measurements; computer modeling of an existing stepped frequency radiometer in an effort to determine its optimum operational characteristics; investigation of the classical second order analog control loop to determine its ability to reduce the estimation error in a microwave radiometer; investigation of several digital signal processing unit designs; initiation of efforts to develop required hardware and software for implementation of the digital signal processing unit; and investigation of the general characteristics and peculiarities of digital processing noiselike microwave radiometer signals.

  6. COBE differential microwave radiometers - Calibration techniques

    NASA Technical Reports Server (NTRS)

    Bennett, C. L.; Smoot, G. F.; Janssen, M.; Gulkis, S.; Kogut, A.; Hinshaw, G.; Backus, C.; Hauser, M. G.; Mather, J. C.; Rokke, L.

    1992-01-01

    The COBE spacecraft was launched November 18, 1989 UT carrying three scientific instruments into earth orbit for studies of cosmology. One of these instruments, the Differential Microwave Radiometer (DMR), is designed to measure the large-angular-scale temperature anisotropy of the cosmic microwave background radiation at three frequencies (31.5, 53, and 90 GHz). This paper presents three methods used to calibrate the DMR. First, the signal difference between beam-filling hot and cold targets observed on the ground provides a primary calibration that is transferred to space by noise sources internal to the instrument. Second, the moon is used in flight as an external calibration source. Third, the signal arising from the Doppler effect due to the earth's motion around the barycenter of the solar system is used as an external calibration source. Preliminary analysis of the external source calibration techniques confirms the accuracy of the currently more precise ground-based calibration. Assuming the noise source behavior did not change from the ground-based calibration to flight, a 0.1-0.4 percent relative and 0.7-2.5 percent absolute calibration uncertainty is derived, depending on radiometer channel.

  7. COBE differential microwave radiometers - Calibration techniques

    NASA Technical Reports Server (NTRS)

    Bennett, C. L.; Smoot, G. F.; Janssen, M.; Gulkis, S.; Kogut, A.; Hinshaw, G.; Backus, C.; Hauser, M. G.; Mather, J. C.; Rokke, L.

    1992-01-01

    The COBE spacecraft was launched November 18, 1989 UT carrying three scientific instruments into earth orbit for studies of cosmology. One of these instruments, the Differential Microwave Radiometer (DMR), is designed to measure the large-angular-scale temperature anisotropy of the cosmic microwave background radiation at three frequencies (31.5, 53, and 90 GHz). This paper presents three methods used to calibrate the DMR. First, the signal difference between beam-filling hot and cold targets observed on the ground provides a primary calibration that is transferred to space by noise sources internal to the instrument. Second, the moon is used in flight as an external calibration source. Third, the signal arising from the Doppler effect due to the earth's motion around the barycenter of the solar system is used as an external calibration source. Preliminary analysis of the external source calibration techniques confirms the accuracy of the currently more precise ground-based calibration. Assuming the noise source behavior did not change from the ground-based calibration to flight, a 0.1-0.4 percent relative and 0.7-2.5 percent absolute calibration uncertainty is derived, depending on radiometer channel.

  8. Wide-Band Airborne Microwave and Millimeter-Wave Radiometers to Provide High-Resolution Wet-Tropospheric Path Delay Corrections for Coastal and Inland Water Altimetry

    NASA Astrophysics Data System (ADS)

    Reising, Steven C.; Kangaslahti, Pekka; Brown, Shannon T.; Tanner, Alan B.; Padmanabhan, Sharmila; Parashare, Chaitali; Montes, Oliver; Dawson, Douglas E.; Gaier, Todd C.; Khayatian, Behrouz; Bosch-Lluis, Xavier; Nelson, Scott P.; Johnson, Thaddeus; Hadel, Victoria; Gilliam, Kyle L.; Razavi, Behzad

    2013-04-01

    Current satellite ocean altimeters include nadir-viewing, co-located 18-34 GHz microwave radiometers to measure wet-tropospheric path delay. Due to the area of the surface instantaneous fields of view (IFOV) at these frequencies, the accuracy of wet path retrievals is substantially degraded near coastlines, and retrievals are not provided over land. Retrievals are flagged as not useful about 40 km from the world's coastlines. A viable approach to improve their capability is to add wide-band millimeter-wave window channels at 90 to 170 GHz, yielding finer spatial resolution for a fixed antenna size. In addition, NASA's Surface Water and Ocean Topography (SWOT) mission in formulation (Phase A) is planned for launch in late 2020. The primary objectives of SWOT are to characterize ocean sub-mesoscale processes on 10-km and larger scales in the global oceans, and to measure the global water storage in inland surface water bodies and the flow rate of rivers. Therefore, an important new science objective of SWOT is to transition satellite radar altimetry into the coastal zone. The addition of millimeter-wave channels near 90, 130 and 166 GHz to current Jason-class radiometers is expected to improve retrievals of wet-tropospheric delay in coastal areas and to enhance the potential for over-land retrievals. The Ocean Surface Topography Science Team Meeting recommended in 2012 to add these millimeter-wave channels to the Jason Continuity of Service (CS) mission. To reduce the risks associated with wet-tropospheric path delay correction over coastal areas and fresh water bodies, we are developing an airborne radiometer with 18.7, 23.8 and 34.0 GHz microwave channels, as well as millimeter-wave window channels at 90, 130 and 166 GHz, and temperature sounding above 118 as well as water vapor sounding below 183 GHz for validation of wet-path delay. For nadir-viewing space-borne radiometers with no moving parts, two-point internal calibration sources are necessary, and the

  9. Tomographic retrieval of cloud liquid water fields from a single scanning microwave radiometer aboard a moving platform – Part 2: Observation system simulation experiments

    SciTech Connect

    Huang, D.; Gasiewski, A.; Wiscombe, W.

    2010-07-01

    Part 1 of this research concluded that many conditions of the 2003 Wakasa Bay experiment were not optimal for the purpose of tomographic retrieval. Part 2 (this paper) then aims to find possible improvements to the mobile cloud tomography method using observation system simulation experiments. We demonstrate that the incorporation of the L{sub 1} norm total variation regularization in the tomographic retrieval algorithm better reproduces discontinuous structures than the widely used L{sub 2} norm Tikhonov regularization. The simulation experiments reveal that a typical ground-based mobile setup substantially outperforms an airborne one because the ground-based setup usually moves slower and has greater contrast in microwave brightness between clouds and the background. It is shown that, as expected, the error in the cloud tomography retrievals increases monotonically with both the radiometer noise level and the uncertainty in the estimate of background brightness temperature. It is also revealed that a lower speed of platform motion or a faster scanning radiometer results in more scan cycles and more overlap between the swaths of successive scan cycles, both of which help to improve the retrieval accuracy. The last factor examined is aircraft height. It is found that the optimal aircraft height is 0.5 to 1.0 km above the cloud top. To summarize, this research demonstrates the feasibility of tomographically retrieving the spatial structure of cloud liquid water using current microwave radiometric technology and provides several general guidelines to improve future field-based studies of cloud tomography.

  10. Sensor Calibration and Ocean Products for TRMM Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Lawrence, Richard J. (Technical Monitor); Wentz, Frank J.

    2003-01-01

    During the three years of fundin& we have carefully corrected for two sensor/platform problems, developed a physically based retrieval algorithm to calculate SST, wind speed, water vapor, cloud liquid water and rain rates, validated these variables, and demonstrated that satellite microwave radiometers can provide very accurate SST retrievals through clouds. Prior to this, there was doubt by some scientists that the technique of microwave SST retrieval from satellites is a viable option. We think we have put these concerns to rest, and look forward to making microwave SSTs a standard component of the Earth science data sets. Our TMI SSTs were featured on several network news broadcasts and were reported in Science magazine. Additionally, we have developed a SST algorithm for VIRS to facilitate IR/MW inter-comparisons and completed research into diurnal cycles and air-sea interactions.

  11. Sensor Calibration and Ocean Products for TRMM Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Wentz, Frank J.; Lawrence, Richard J. (Technical Monitor)

    2003-01-01

    During the three years of finding, we have carefully corrected for two sensor/platform problems, developed a physically based retrieval algorithm to calculate SST, wind speed, water vapor, cloud liquid water and rain rates, validated these variables, and demonstrated that satellite microwave radiometers can provide very accurate SST retrievals through clouds. Prior to this, there was doubt by some scientists that the technique of microwave SST retrieval from satellites is a viable option. We think we have put these concerns to rest, and look forward to making microwave SSTs a standard component of the Earth science data sets. Our TMI SSTs were featured on several network news broadcasts and were reported in Science magazine. Additionally, we have developed a SST algorithm for VIRS to facilitate IR/MW inter-comparisons and completed research into diurnal cycles and air-sea interactions.

  12. Sensor Calibration and Ocean Products for TRMM Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Lawrence, Richard J. (Technical Monitor); Wentz, Frank J.

    2003-01-01

    During the three years of fundin& we have carefully corrected for two sensor/platform problems, developed a physically based retrieval algorithm to calculate SST, wind speed, water vapor, cloud liquid water and rain rates, validated these variables, and demonstrated that satellite microwave radiometers can provide very accurate SST retrievals through clouds. Prior to this, there was doubt by some scientists that the technique of microwave SST retrieval from satellites is a viable option. We think we have put these concerns to rest, and look forward to making microwave SSTs a standard component of the Earth science data sets. Our TMI SSTs were featured on several network news broadcasts and were reported in Science magazine. Additionally, we have developed a SST algorithm for VIRS to facilitate IR/MW inter-comparisons and completed research into diurnal cycles and air-sea interactions.

  13. Comparison of Profiling Microwave Radiometer, Aircraft, and Radiosonde Measurements From the Alliance Icing Research Study (AIRS)

    NASA Technical Reports Server (NTRS)

    Reehorst, Andrew L.

    2001-01-01

    Measurements from a profiling microwave radiometer are compared to measurements from a research aircraft and radiosondes. Data compared is temperature, water vapor, and liquid water profiles. Data was gathered at the Alliance Icing Research Study (AIRS) at Mirabel Airport outside Montreal, Canada during December 1999 and January 2000. All radiometer measurements were found to lose accuracy when the radome was wet. When the radome was not wetted, the radiometer was seen to indicate an inverted distribution of liquid water within a cloud. When the radiometer measurements were made at 15 deg. instead of the standard zenith, the measurements were less accurate.

  14. Stratus cloud liquid water and turbulence profiles using a K{sub {alpha}}-band Doppler radar and a microwave radiometer

    SciTech Connect

    Frisch, A.S.; Fairall, C.W.; Snider, J.B.; Lenschow, D.H.

    1994-12-31

    The goal of the Atlantic Stratocumulus Transition Experiment (ASTEX) held in the North Atlantic during June 1992 was to determine the physical reasons for the transition from stratocumulus to broken clouds. Some possible reasons for this transition were such things as cloud top entrainment instability, and the decoupling effects of drizzle. As part of this experiment, the ETL cloud sensing Doppler radar and three channel microwave radiometer were deployed on the island of Porto Santo in the Madeira Islands of Portugal along with a CO{sub 2} Doppler lider. Drizzle properties in stratus were examined using a log-normal droplet distribution model which related the three parameters of the model to the first 3 Doppler spectral moments of the cloud radar. With these moments, the authors are then able to compute the drizzle droplet concentration, modal radius, liquid water and liquid water flux as a function of height.

  15. Microwave integrated circuit radiometer front-ends for the Push Broom Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Harrington, R. F.; Hearn, C. P.

    1982-01-01

    Microwave integrated circuit front-ends for the L-band, S-band and C-band stepped frequency null-balanced noise-injection Dicke-switched radiometer to be installed in the NASA Langley airborne prototype Push Broom Microwave Radiometer (PBMR) are described. These front-ends were developed for the fixed frequency of 1.413 GHz and the variable frequencies of 1.8-2.8 GHz and 3.8-5.8 GHz. Measurements of the noise temperature of these units were made at 55.8 C, and the results of these tests are given. While the overall performance was reasonable, improvements need to be made in circuit losses and noise temperatures, which in the case of the C-band were from 1000 to 1850 K instead of the 500 K specified. Further development of the prototypes is underway to improve performance and extend the frequency range.

  16. Microwave integrated circuit radiometer front-ends for the Push Broom Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Harrington, R. F.; Hearn, C. P.

    1982-01-01

    Microwave integrated circuit front-ends for the L-band, S-band and C-band stepped frequency null-balanced noise-injection Dicke-switched radiometer to be installed in the NASA Langley airborne prototype Push Broom Microwave Radiometer (PBMR) are described. These front-ends were developed for the fixed frequency of 1.413 GHz and the variable frequencies of 1.8-2.8 GHz and 3.8-5.8 GHz. Measurements of the noise temperature of these units were made at 55.8 C, and the results of these tests are given. While the overall performance was reasonable, improvements need to be made in circuit losses and noise temperatures, which in the case of the C-band were from 1000 to 1850 K instead of the 500 K specified. Further development of the prototypes is underway to improve performance and extend the frequency range.

  17. Application of microwave radiometers for wetlands and estuaries monitoring

    SciTech Connect

    Shutko, A.; Haldin, A.; Novichikhin, E.

    1997-06-01

    This paper presents the examples of experimental data obtained with airborne microwave radiometers used for monitoring of wetlands and estuaries located in coastal environments. The international team of researchers has successfully worked in Russia, Ukraine and USA. The data presented relate to a period of time between 1990 and 1995. They have been collected in Odessa Region, Black Sea coast, Ukraine, in Regions of Pittsville and Winfield, Maryland, USA, and in Region of St. Marks, Florida, USA. The parameters discussed are a soil moisture, depth to a shallow water table, vegetation index, salinity of water surface.

  18. Stable Targets for Spaceborne Microwave Radiometer Calibration

    NASA Technical Reports Server (NTRS)

    Njoku, Eni G.; Chan, S. K.; Armstrong, R. L.; Brodzik, M. J.; Savoie, M. H.; Knowles, K.

    2006-01-01

    Beginning in the 1970s, continuous observations of the Earth have been made by spaceborne microwave radiometers. Since these instruments have different observational characteristics, care must be taken in combining their data to form consistent long term records of brightness temperatures and derived geophysical quantities. To be useful for climate studies, data from different instruments must be calibrated relative to each other and to reference targets on the ground whose characteristics are stable and can be monitored continuously. Identifying such targets over land is not straightforward due to the heterogeneity and complexity of the land surface and cover. In this work, we provide an analysis of multi-sensor brightness temperature statistics over ocean, tropical forest, and ice sheet locations, spanning the period from 1978 to the present, and indicate the potential of these sites as continuous calibration monitoring targets.

  19. Advanced microwave radiometer antenna system study

    NASA Technical Reports Server (NTRS)

    Kummer, W. H.; Villeneuve, A. T.; Seaton, A. F.

    1976-01-01

    The practicability of a multi-frequency antenna for spaceborne microwave radiometers was considered in detail. The program consisted of a comparative study of various antenna systems, both mechanically and electronically scanned, in relation to specified design goals and desired system performance. The study involved several distinct tasks: definition of candidate antennas that are lightweight and that, at the specified frequencies of 5, 10, 18, 22, and 36 GHz, can provide conical scanning, dual linear polarization, and simultaneous multiple frequency operation; examination of various feed systems and phase-shifting techniques; detailed analysis of several key performance parameters such as beam efficiency, sidelobe level, and antenna beam footprint size; and conception of an antenna/feed system that could meet the design goals. Candidate antennas examined include phased arrays, lenses, and optical reflector systems. Mechanical, electrical, and performance characteristics of the various systems were tabulated for ease of comparison.

  20. Microwave radiometer observations of soil moisture in HAPEX-SAHEL

    NASA Astrophysics Data System (ADS)

    Schmugge, Thomas J.; Chanzy, Andre; Kerr, Yann H.; van Oevelen, Peter

    1995-01-01

    Water stored in the soil serves as the reservoir for the evapotranspiration process, thus the interest in trying to map its spatial and temporal variations in experiments studying the soil- plant-atmosphere interactions at the GCM grid scale. During the 8 week intensive observation period (IOP) of HAPEX-Sahel (Hydrologic Atmospheric Pilot Experiment in the Sahel), this was done with two airborne microwave radiometer systems. The five frequency (5 to 90 GHz) PORTOS radiometer on the French ARAT aircraft and the single frequency (1.42 GHz) multibeam pushbroom microwave radiometer (PBMR) on the NASA C-130 were used. These aircraft measurements were supported by ground based observations at the central sites and, because of several rains during the IOP, covered a good range of soil wetness conditions that existed. The PBMR and the 5.05 GHz PORTOS channel in H polarization show a large dynamic range of TB on each day and between different days in response to variations in rainfall and drying conditions ranging from low TBs of 210 to 220 K for the wettest conditions to values of 280 to 290 K for the driest.

  1. Mapping the sky with the COBE differential microwave radiometers

    NASA Technical Reports Server (NTRS)

    Janssen, M. A.; Gulkis, S.

    1992-01-01

    The Differential Microwave Radiometers (DMR) instrument on COBE is designed to determine the anisotropy of the Cosmic Microwave Background by providing all-sky maps of the diffuse sky brightness at microwave frequencies. The principal intent of this lecture is to show how these maps are generated from differential measurements.

  2. Multichannel infrared fiber optic radiometer for controlled microwave heating

    NASA Astrophysics Data System (ADS)

    Drizlikh, S.; Zur, Albert; Katzir, Abraham

    1990-07-01

    An infrared fiberoptic multichannel radiometer was used for monitoring and controlling the temperature of samples in a microwave heating system. The temperature of water samples was maintained at about 40 °C, with a standard deviation of +/- 0.2°C and a maximum deviation of +/- 0.5°C. The temperature was monitored on the same time at several points on the surface and inside the sample. This novel controlled system is reliable and precise. Such system would be very useful for medical applications such as hypothermia and hyperthermi a.

  3. Progress report of FY 1999 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

    SciTech Connect

    Edgeworth R. Westwater; Yong Han

    1999-09-10

    Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this effort is to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. While analyzing data obtained during the Water Vapor Intensive Operating Period'97 at the SGP CART site in central Oklahoma, several questions arose about the calibration of the ARM microwave radiometers (MWR). A large portion of this years effort was a thorough analysis of the many factors that are important for the calibration of this instrument through the tip calibration method and the development of algorithms to correct this procedure. An open literature publication describing this analysis has been accepted.

  4. Passive microwave sensing of coastal area waters

    NASA Technical Reports Server (NTRS)

    Kendall, B. M.

    1980-01-01

    A technique to remotely measure sea-surface temperature and salinity was demonstrated during the 1970's with a dual-frequency microwave radiometer system developed at the NASA Langley Research Center. Accuracies in temperature of 1 C and 1 part per thousand in salinity were obtained using state-of-the-art radiometers. Several aircraft programs for the measurement of coastal area waters demonstrating the application of the microwave radiometer system are discussed. Improvements of the microwave radiometer system during the 1980's and the design and development of new radiometer systems at other frequencies are outlined and related to potential applications.

  5. Sensitivity of Spacebased Microwave Radiometer Observations to Ocean Surface Evaporation

    NASA Technical Reports Server (NTRS)

    Liu, Timothy W.; Li, Li

    2000-01-01

    Ocean surface evaporation and the latent heat it carries are the major components of the hydrologic and thermal forcing on the global oceans. However, there is practically no direct in situ measurements. Evaporation estimated from bulk parameterization methods depends on the quality and distribution of volunteer-ship reports which are far less than satisfactory. The only way to monitor evaporation with sufficient temporal and spatial resolutions to study global environment changes is by spaceborne sensors. The estimation of seasonal-to-interannual variation of ocean evaporation, using spacebased measurements of wind speed, sea surface temperature (SST), and integrated water vapor, through bulk parameterization method,s was achieved with reasonable success over most of the global ocean, in the past decade. Because all the three geophysical parameters can be retrieved from the radiance at the frequencies measured by the Scanning Multichannel Microwave Radiometer (SMMR) on Nimbus-7, the feasibility of retrieving evaporation directly from the measured radiance was suggested and demonstrated using coincident brightness temperatures observed by SMMR and latent heat flux computed from ship data, in the monthly time scale. However, the operational microwave radiometers that followed SMMR, the Special Sensor Microwave/Imager (SSM/I), lack the low frequency channels which are sensitive to SST. This low frequency channels are again included in the microwave imager (TMI) of the recently launched Tropical Rain Measuring Mission (TRMM). The radiance at the frequencies observed by both TMI and SSM/I were simulated through an atmospheric radiative transfer model using ocean surface parameters and atmospheric temperature and humidity profiles produced by the reanalysis of the European Center for Medium Range Weather Forecast (ECMWF). From the same ECMWF data set, coincident evaporation is computed using a surface layer turbulent transfer model. The sensitivity of the radiance to

  6. Sensitivity of Spacebased Microwave Radiometer Observations to Ocean Surface Evaporation

    NASA Technical Reports Server (NTRS)

    Liu, Timothy W.; Li, Li

    2000-01-01

    Ocean surface evaporation and the latent heat it carries are the major components of the hydrologic and thermal forcing on the global oceans. However, there is practically no direct in situ measurements. Evaporation estimated from bulk parameterization methods depends on the quality and distribution of volunteer-ship reports which are far less than satisfactory. The only way to monitor evaporation with sufficient temporal and spatial resolutions to study global environment changes is by spaceborne sensors. The estimation of seasonal-to-interannual variation of ocean evaporation, using spacebased measurements of wind speed, sea surface temperature (SST), and integrated water vapor, through bulk parameterization method,s was achieved with reasonable success over most of the global ocean, in the past decade. Because all the three geophysical parameters can be retrieved from the radiance at the frequencies measured by the Scanning Multichannel Microwave Radiometer (SMMR) on Nimbus-7, the feasibility of retrieving evaporation directly from the measured radiance was suggested and demonstrated using coincident brightness temperatures observed by SMMR and latent heat flux computed from ship data, in the monthly time scale. However, the operational microwave radiometers that followed SMMR, the Special Sensor Microwave/Imager (SSM/I), lack the low frequency channels which are sensitive to SST. This low frequency channels are again included in the microwave imager (TMI) of the recently launched Tropical Rain Measuring Mission (TRMM). The radiance at the frequencies observed by both TMI and SSM/I were simulated through an atmospheric radiative transfer model using ocean surface parameters and atmospheric temperature and humidity profiles produced by the reanalysis of the European Center for Medium Range Weather Forecast (ECMWF). From the same ECMWF data set, coincident evaporation is computed using a surface layer turbulent transfer model. The sensitivity of the radiance to

  7. Precipitation Estimation Using Combined Radar and Microwave Radiometer Observations from - Improvements and Initial Validation

    NASA Astrophysics Data System (ADS)

    Olson, W. S.; Grecu, M.; Munchak, S. J.; Kuo, K. S.; Johnson, B. T.; Haddad, Z. S.; Tian, L.; Liao, L.; Kelley, B. L.; Ringerud, S.

    2015-12-01

    In recent satellite missions, spaceborne radar observations, sometimes in combination with passive microwave radiometer measurements, are being used to estimate vertical profiles of precipitation rates. Launched in 2014, the Global Precipitation Measurement (GPM) mission core satellite observatory features a dual-frequency radar operating at 13.6 and 35.5 GHz (Ku and Ka bands) and a microwave radiometer with thirteen channels from 10 - 183 GHz. The use of combined radar and radiometer observations should yield the most accurate estimates of precipitation profiles from space, and these estimates will ultimately serve as a crucial reference for cross-calibrating passive microwave precipitation estimates from the GPM radiometer constellation. And through the microwave radiometer estimates, the combined algorithm calibration will ultimately be propagated to GPM infrared-microwave multisatellite estimates of surface rainfall. The GPM combined precipitation estimation algorithm performs initial estimates (an "ensemble") of precipitation profiles based upon an observed Ku-band reflectivity profile and different a priori assumptions concerning the size distributions of the precipitation particles and the profiles of cloud water and water vapor in the atmospheric column. The initial ensemble of profiles is then updated using a filter that embodies the physics relating precipitation to the observed Ka reflectivity profile, Ku and Ka path-integrated attenuation (derived from radar surface backscatter measurements), and microwave radiances. The final, filtered ensemble of profiles is consistent with all the available radar-radiometer data and a priori information. Since the GPM launch, the combined radar-radiometer algorithm has been improved to more specifically account for the effects of radar non-uniform beamfilling, multiple-scattering of radar pulses, the different resolutions of the radar and radiometer observations, interrelated radar and passive microwave surface

  8. A Microwave Radiometer for Internal Body Temperature Measurement

    NASA Astrophysics Data System (ADS)

    Scheeler, Robert Patterson

    This thesis presents the analysis and design of a microwave radiometer for internal body temperature measurements. There is currently no available method for non-invasive temperature measurement inside the human body. However, knowledge of both relative and absolute temperature variations over time is important to a number of medical applications. The research presented in this thesis details a proof-of-concept near-field microwave radiometer demonstrating relative thermometry of a multi-layer phantom. There are a number of technical challenges addressed in this thesis for radiometric determination of sub-degree temperature variations in the human body. A theoretical approach is developed for determining sensing depth from known complex layered tissues, which is defined as a figure of merit, and is shown to be dependent on frequency, electrical properties of the tissues, and the near-field probe. In order to obtain depth resolution, multiple frequency operation can be used, so multi-frequency probes are designed and demonstrated in this work. The choice of frequencies is determined not only by the tissue material properties, but also by the ever increasing radio interference in the environment. In this work, quiet bands allocated to radio astronomy are investigated. The radiometer and probe need to be compact to be wearable, and several advancements are made towards a fully wearable device: multi-frequency low-profile probes are designed and fabricated on a flexible substrate and the process of on-chip integration is demonstrated by a GaAs MMIC cold noise source for radiometer calibration. The implemented proof-of-concept device consists of two radiometers at 1.4 GHz and 2.7 GHz, designed with commercial inexpensive devices that can enable sufficient sensitivity. The device is tested on a phantom with two water layers whose temperatures are varied in a controlled manner, and focused on the human body temperature range. Measured results are discussed qualitatively

  9. Intercomparison Between Microwave Radiometer and Radiosonding Data

    NASA Astrophysics Data System (ADS)

    Toanca, Florica; Stefan, Sabina

    2014-05-01

    The aim of this study is to compare relative humidity and temperature vertical profiles measured by ground based Microwave Radiometer (MWR) RPG HATPRO installed at the Romanian Atmospheric Observatory (Magurele, 44.35 N, 26.03 E) and by radio-sounding (RS) (Baneasa, 44.30 N, 26.04 E) provided by National Meteorological Administration. MWR uses passive microwave detection in the 22.335 to 31.4 GHz and 51to 58 GHz bands to obtain the vertical profiles of temperature and relative humidity up to 10km with a temporal resolution of several minutes. The reliability of atmospheric temperature and relative humidity profiles retrieved continuously by the MWR for the winter and summer of year 2013 was studied. The study was conducted, comparing the temperature and humidity profiles from the MWR with the ones from the radio soundings at 0:00 a.m. Two datasets of the humidity show a fairly good agreement for the interval between ground and 1.5 km in the January month for winter and up to 2 km in the July month for summer. Above 2 km, for the both seasons, the humidity profiles present in most of the selected cases the same trend evolution. The temperature vertical profiles agreed in 95% of the cases during summer and 85% during winter. It is very important for intercomparison that for both seasons almost all temperature vertical profiles highlight temperature inversions. Two cases have been analyzed in order to find possible explanations for the discrepancies between vertical profiles, focusing on advantages and disadvantages of MWR measurements.

  10. A 15-meter deployable aperture microwave radiometer

    NASA Technical Reports Server (NTRS)

    Coyner, J. V., Jr.

    1983-01-01

    The Large Antenna Multifrequency Microwave Radiometer (LAMMR) was a 4-meter-diameter mechanically scanned (at 1 rps) antenna operating at frequencies from 4.3 to 36 GHz. This LAMMR system was scheduled to fly on the National Oceanic Satellite System (NOSS) in 1986 to measure sea surface temperature and wind speed along with several other atmospheric and sea ice parameters. The LAMMR was limited to a 4-meter solid reflector to stay within the Shuttle/NOSS launch volume and to operate with radiometric precision up to 36.5 GHz. Under the 4-meter aperture constraint, LAMMR could not meet the user resolution requirement for sea surface temperature (25 km minimum, 50 km goal) in an RFI free band, i.e., 4.3 GHz. This study explores the feasibility of meeting this requirement goal with a 15-meter mechanically scanned deployable reflector. Two other research objectives can also be studied by adding one active (approximately 5 GHz) and two additional passive (1.4 and 6.4 GHz) channels to investigate soil moisture and precipitation profiles over land. These two objectives are closely related because the precipitation is the source of the soil moisture in unirrigated regions, and the soil moisture changes between samples (2/day) could indicate that precipitation may have occurred while the sensor was not in view.

  11. Remote monitoring of soil moisture using airborne microwave radiometers

    NASA Technical Reports Server (NTRS)

    Kroll, C. L.

    1973-01-01

    The current status of microwave radiometry is provided. The fundamentals of the microwave radiometer are reviewed with particular reference to airborne operations, and the interpretative procedures normally used for the modeling of the apparent temperature are presented. Airborne microwave radiometer measurements were made over selected flight lines in Chickasha, Oklahoma and Weslaco, Texas. Extensive ground measurements of soil moisture were made in support of the aircraft mission over the two locations. In addition, laboratory determination of the complex permittivities of soil samples taken from the flight lines were made with varying moisture contents. The data were analyzed to determine the degree of correlation between measured apparent temperatures and soil moisture content.

  12. Progress report of FY 1997 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

    SciTech Connect

    Edgeworth R. Westwater; Yong Han

    1997-10-05

    Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this proposal was to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. The algorithm will include recently-developed quality control procedures for radiometers. The focus of this years activities has been on the intercomparison of data obtained during an intensive operating period at the SGP CART site in central Oklahoma.

  13. Precipitation from the GPM Microwave Imager and Constellation Radiometers

    NASA Astrophysics Data System (ADS)

    Kummerow, Christian; Randel, David; Kirstetter, Pierre-Emmanuel; Kulie, Mark; Wang, Nai-Yu

    2014-05-01

    Satellite precipitation retrievals from microwave sensors are fundamentally underconstrained requiring either implicit or explicit a-priori information to constrain solutions. The radiometer algorithm designed for the GPM core and constellation satellites makes this a-priori information explicit in the form of a database of possible rain structures from the GPM core satellite and a Bayesian retrieval scheme. The a-priori database will eventually come from the GPM core satellite's combined radar/radiometer retrieval algorithm. That product is physically constrained to ensure radiometric consistency between the radars and radiometers and is thus ideally suited to create the a-priori databases for all radiometers in the GPM constellation. Until a robust product exists, however, the a-priori databases are being generated from the combination of existing sources over land and oceans. Over oceans, the Day-1 GPM radiometer algorithm uses the TRMM PR/TMI physically derived hydrometer profiles that are available from the tropics through sea surface temperatures of approximately 285K. For colder sea surface temperatures, the existing profiles are used with lower hydrometeor layers removed to correspond to colder conditions. While not ideal, the results appear to be reasonable placeholders until the full GPM database can be constructed. It is more difficult to construct physically consistent profiles over land due to ambiguities in surface emissivities as well as details of the ice scattering that dominates brightness temperature signatures over land. Over land, the a-priori databases have therefore been constructed by matching satellite overpasses to surface radar data derived from the WSR-88 network over the continental United States through the National Mosaic and Multi-Sensor QPE (NMQ) initiative. Databases are generated as a function of land type (4 categories of increasing vegetation cover as well as 4 categories of increasing snow depth), land surface temperature and

  14. Jupiter's global ammonia distribution inferred from Juno Microwave Radiometer Observations

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Ingersoll, Andrew; Ewald, Shawn; Oyafuso, Fabiano; Janssen, Michael

    2017-04-01

    The Juno microwave radiometer (Juno/MWR) has made several observations of Jupiter's atmosphere by measuring the thermal emission from pressure levels down to a few hundred bars. The main objective of Juno/MWR is to determine Jupiter's deep water abundance because water is the key to understand Jovian meteorology that we observe at the cloud level, and because the deep water abundance hints at a giant planet's volatile and heavy element history. Since ammonia is the major opacity source in the Juno/MWR channels, it is especially important to figure out the ammonia distribution before we can conclude anything on the water abundance. At this stage of our analysis, we have inverted a global map (vertical and latitudinal) of ammonia distribution from the observed brightness temperatures at six wavelengths using the Markov Chain Monte Carlo technique. This method fully calibrates error and explores a wide range of the parameter space to avoid falling into a local minimum. The robustness of the retrieval is explained by matching the features in the ammonia distribution with the features in the microwave spectra. We will also announce the initial result of the retrieval of water abundance using the same technique.

  15. Multibeam 1.4-GHz Pushbroom Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Lawrence, Roland W.; Bailey, Marion C.; Harrington, Richard F.; Hearn, Chase P.; Wells, John G., Jr.; Stanley, William L.

    1990-01-01

    Airborne prototype of multiple-beam pushbroom microwave radiometer (PBMR) developed to advance radiometric technology necessary for remote sensing of geophysical parameters. Instrument used in several joint Langley Research Center/United States Department of Agriculture soil-moisture flight experiments in Virginia, Texas, and California. Data from experiments used to modify, develop, and verify algorithms used to predict soil moisture from remote-sensing measurements. Image data useful in study of effects of characters of beams on radiometer imaging data.

  16. ESTAR - A synthetic aperture microwave radiometer for measuring soil moisture

    NASA Technical Reports Server (NTRS)

    Le Vine, D. M.; Griffis, A.; Swift, C. T.; Jackson, T. J.

    1992-01-01

    The measurement of soil moisture from space requires putting relatively large microwave antennas in orbit. Aperture synthesis, an interferometric technique for reducing the antenna aperture needed in space, offers the potential for a practical means of meeting these requirements. An aircraft prototype, electronically steered thinned array L-band radiometer (ESTAR), has been built to develop this concept and to demonstrate its suitability for the measurement of soil moisture. Recent flights over the Walnut Gulch Watershed in Arizona show good agreement with ground truth and with measurements with the Pushbroom Microwave Radiometer (PBMR).

  17. ESTAR - A synthetic aperture microwave radiometer for measuring soil moisture

    NASA Technical Reports Server (NTRS)

    Le Vine, D. M.; Griffis, A.; Swift, C. T.; Jackson, T. J.

    1992-01-01

    The measurement of soil moisture from space requires putting relatively large microwave antennas in orbit. Aperture synthesis, an interferometric technique for reducing the antenna aperture needed in space, offers the potential for a practical means of meeting these requirements. An aircraft prototype, electronically steered thinned array L-band radiometer (ESTAR), has been built to develop this concept and to demonstrate its suitability for the measurement of soil moisture. Recent flights over the Walnut Gulch Watershed in Arizona show good agreement with ground truth and with measurements with the Pushbroom Microwave Radiometer (PBMR).

  18. Progress report of FY 1998 activities: The application of Kalman filtering to derive water vapor profiles from combined ground-based sensors: Raman lidar, microwave radiometers, GPS, and radiosondes

    SciTech Connect

    Edgeworth R. Westwater; Yong Han

    1999-10-01

    Previously, the proposers have delivered to ARM a documented algorithm, that is now applied operationally, and which derives water vapor profiles from combined remote sensor measurements of water vapor radiometers, cloud-base ceilometers, and radio acoustic sounding systems (RASS). With the expanded deployment of a Raman lidar at the CART Central Facility, high quality, high vertical-resolution, water vapor profiles will be provided during nighttime clear conditions, and during clear daytime conditions, to somewhat lower altitudes. The object of this effort is to use Kalman Filtering, previously applied to the combination of nighttime Raman lidar and microwave radiometer data, to derive high-quality water vapor profiles, during non-precipitating conditions, from data routinely available at the CART site. Input data to the algorithm would include: Raman lidar data, highly quality-controlled data of integrated moisture from microwave radiometers and GPS, RASS, and radiosondes. The focus of this years activities has been on the intercomparison of data obtained during the Water Vapor Intensive Operating Period'97 at the SGP CART site in central Oklahoma.

  19. Microwave radiometer for subsurface temperature measurement

    NASA Technical Reports Server (NTRS)

    Porter, R. A.; Bechis, K. P.

    1976-01-01

    A UHF radiometer, operating at a frequency of 800 MHz, was modified to provide an integral, three frequency voltage standing wave ratio (VSWR) circuit in the radio frequency (RF) head. The VSWR circuit provides readings of power transmission at the antenna-material interface with an accuracy of plus or minus 5 percent. The power transmission readings are numerically equal to the emissivity of the material under observation. Knowledge of material emissivity is useful in the interpretation of subsurface apparent temperatures obtained on phantom models of biological tissue. The emissivities of phantom models consisting of lean beefsteak were found to lie in the range 0.623 to 0.779, depending on moisture content. Radiometric measurements performed on instrumented phantoms showed that the radiometer was capable of sensing small temperature changes occurring at depths of at least 19 to 30 mm. This is consistent with previously generated data which showed that the radiometer could sense temperatures at a depth of 38 mm.

  20. Source analysis of spaceborne microwave radiometer interference over land

    NASA Astrophysics Data System (ADS)

    Guan, Li; Zhang, Sibo

    2016-03-01

    Satellite microwave thermal emissions mixed with signals from active sensors are referred to as radiofrequency interference (RFI). Based on Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) observations from June 1 to 16, 2011, RFI over Europe was identified and analyzed using the modified principal component analysis algorithm in this paper. The X band AMSR-E measurements in England and Italy are mostly affected by the stable, persistent, active microwave transmitters on the surface, while the RFI source of other European countries is the interference of the reflected geostationary TV satellite downlink signals to the measurements of spaceborne microwave radiometers. The locations and intensities of the RFI induced by the geostationary TV and communication satellites changed with time within the observed period. The observations of spaceborne microwave radiometers in ascending portions of orbits are usually interfered with over European land, while no RFI was detected in descending passes. The RFI locations and intensities from the reflection of downlink radiation are highly dependent upon the relative geometry between the geostationary satellite and the measuring passive sensor. Only these fields of view of a spaceborne instrument whose scan azimuths are close to the azimuth relative to the geostationary satellite are likely to be affected by RFI.

  1. Feasibility of detecting aircraft wake vortices using passive microwave radiometers

    NASA Technical Reports Server (NTRS)

    Harrington, Richard F.

    1993-01-01

    The feasibility of detecting the cold core of the wake vortex from the wingtips of an aircraft using a passive microwave radiometer was investigated. It was determined that there is a possibility that a cold core whose physical temperature drop is 10 C or greater and which has a diameter of 5 m or greater can be detected by a microwave radiometer. The radiometer would be a noise injection balanced Dicke radiometer operating at a center frequency of 60 GHz. It would require a noise figure of 5 dB, a predetection bandwidth of 6 GHz, and an integration time of 2 seconds resulting in a radiometric sensitivity of 0.018 K. However, three additional studies are required. The first would determine what are the fluctuations in the radiometric antenna temperature due to short-term fluctuations in atmospheric pressure, temperature, and relative humidity. Second, what is the effect of the pressure and temperature drop within the cold core of the wake vortex on its opacity. The third area concerns the possibility of developing a 60 GHz radiometer with a radio metric sensitivity an order of magnitude improvement over the existing state of the art.

  2. ENVISAT-1 Microwave Radiometer (MWR): validation campaign achievements

    NASA Astrophysics Data System (ADS)

    Bombaci, Ornella; L'Abbate, Michele; Svara, Carlo; Caltagirone, Francesco; Guijarro, J.

    1998-12-01

    Alenia Aerospazio Remote Sensing Division started in 1986 the study of microwave radiometers under Italian Space Agency fundings, and since 1989 the definition and development of radiometric systems under European Space Agency (ESA) contracts. In particular the Multifrequency Imaging Microwave Radiometer (MIMR) and the ENVISAT Microwave Radiometer (MWR) were both developed by the European Industry, with Alenia Aerospazio as Prime Contractor. MWR is an instrument designed and developed as part of the Envisat-1 satellite scientific payload, with Alenia Spazio engaged in the phase C-D as instrument Prime Contractor, leading an industrial consortium of European and American companies. The Flight Model of the Instrument has been delivered to ESA at the end of July 1997, after completion of test and calibration activities. Given the MWR in-flight calibration concept, a specific pre-flight calibration and characterization activity was performed to define a radiometer mathematical model and a relevant ground characterization database including all model coefficients. The model and its database will be used by on-ground processing during instrument in-flight operation to retrieve the antenna-measured temperature. Standing its complexity and iterative measurement concept, the pre-flight characterization and calibration of the instrument is the key aspect of its development phase. Within this paper the key instrument design topics are summarized, and after a summary overview of the overall flight model qualification campaign, emphasis will be on the pre-flight calibration and characterization activities and radiometric performance achievements among several test phases.

  3. Remote sensing of soil moisture with microwave radiometers

    NASA Technical Reports Server (NTRS)

    Schmugge, T.; Wilheit, T.; Webster, W., Jr.; Gloerson, P.

    1976-01-01

    Results are presented that were derived from measurements made by microwave radiometers during the March 1972 and February 1973 flights of National Aeronautics and Space Administration (NASA) Convair-9900 aircraft over agricultural test sites in the southwestern part of United States. The purpose of the missions was to study the use of microwave radiometers for the remote sensing of soil moisture. The microwave radiometers covered the 0.8- to 21-cm wavelength range. The results show a good linear correlation between the observed microwave brightness temperature and moisture content of the 0- to 1-cm layer of the soil. The results at the largest wavelength (21 cm) show the greatest sensitivity to soil moisture variations and indicate the possibility of sensing these variations through a vegetative canopy. The effect of soil texture on the emission from the soil was also studied and it was found that this effect can be compensated for by expressing soil moisture as a percent of field capacity for the soil. The results were compared with calculations based on a radiative transfer model for layered dielectrics and the agreement is very good at the longer wavelengths. At the shorter wavelengths, surface roughness effects are larger and the agreement becomes poorer.

  4. Progress in Low-Power Digital Microwave Radiometer Technologies

    NASA Technical Reports Server (NTRS)

    Piepmeier, Jeffrey R.; Kim, Edward J.

    2004-01-01

    Three component technologies were combined into a digital correlation microwave radiometer. The radiometer comprises a dual-channel X-band superheterodyne receiver, low-power high-speed cross-correlator (HSCC), three-level ADCs, and a correlated noise source (CNS). The HSCC dissipates 10 mW and operates at 500 MHz clock speed. The ADCs are implemented using ECL components and dissipate more power than desired. Thus, a low-power ADC development is underway. The new ADCs arc predicted to dissipated less than 200 mW and operate at 1 GSps with 1.5 GHz of input bandwidth. The CNS provides different input correlation values for calibration of the radiometer. The correlation channel had a null offset of 0.0008. Test results indicate that the correlation channel can be calibrated with 0.09% error in gain.

  5. Simulation of Antenna Brightness Temperatures for the Juno Microwave Radiometer

    NASA Astrophysics Data System (ADS)

    Oyafuso, F. A.; Gulkis, S.; Adumitroaie, V.; Janssen, M. A.; Atreya, S. K.; Brown, S. T.; Bellotti, A.; Li, C.; Ingersoll, A. P.; Santos-Costa, D.; Williamson, R.; Jewell, L. A.

    2016-12-01

    A major objective of the Juno mission is the determination of global Jovian water and ammonia abundances from measurements by the Juno Microwave Radiometer (MWR). To this end, an instrument simulator has been developed to compute antenna brightness temperatures starting from a simplified atmospheric model of Jupiter involving a small set of tunable (and retrievable) parameters. The atmospheric model is the first element in a pipeline comprised of a number of components, including a model for the radiative transfer, a calculation of the instantaneous position and orientation of the antennae, and a set of precomputed skymaps of synchrotron emission and galactic background radiation. The output of this forward model is a time-ordered series of antenna brightness temperatures which can then be compared to measured data. Here, we primarily focus on details of this calculation but also present preliminary comparisons to MWR data and discuss potential improvements that will be needed to better fit the measurements and retrieve Jupiter's global water and ammonia abundances, hence the oxygen and nitrogen elemental ratios.

  6. Soil Moisture Active/Passive (SMAP) L-band microwave radiometer post-launch calibration

    USDA-ARS?s Scientific Manuscript database

    The SMAP microwave radiometer is a fully-polarimetric L-band radiometer flown on the SMAP satellite in a 6 AM / 6 PM sun-synchronous orbit at 685-km altitude. Since April 2015, the radiometer has been under calibration and validation to assess the quality of the radiometer L1B data product. Calibrat...

  7. Inflatable Antenna Microwave Radiometer for Soil Moisture Measurement

    NASA Technical Reports Server (NTRS)

    Bailey, M. C.; Kendall, Bruce M.; Schroeder, Lyle C.; Harrington, Richard F.

    1993-01-01

    Microwave measurements of soil moisture are not being obtained at the required spatial Earth resolution with current technology. Recently, new novel designs for lightweight reflector systems have been developed using deployable inflatable antenna structures which could enable lightweight real-aperture radiometers. In consideration of this, a study was conducted at the NASA Langley Research Center (LaRC) to determine the feasibility of developing a microwave radiometer system using inflatable reflector antenna technology to obtain high spatial resolution radiometric measurements of soil moisture from low Earth orbit and which could be used with a small and cost effective launch vehicle. The required high resolution with reasonable swath width coupled with the L-band measurement frequency for soil moisture dictated the use of a large (30 meter class) real aperture antenna in conjunction with a pushbroom antenna beam configuration and noise-injection type radiometer designs at 1.4 and 4.3 GHz to produce a 370 kilometer cross-track swath with a 10 kilometer resolution that could be packaged for launch with a Titan 2 class vehicle. This study includes design of the inflatable structure, control analysis, structural and thermal analysis, antenna and feed design, radiometer design, payload packaging, orbital analysis, and electromagnetic losses in the thin membrane inflatable materials.

  8. Scanning mechanism study for multi-frequency microwave radiometers

    NASA Technical Reports Server (NTRS)

    Shin, I.

    1976-01-01

    Scanning mode for a microwave radiometer having large aperture antenna is determined from scientific needs by engineering tradeoffs. Two configurations of the scan drive mechanism with an integral momentum compensation are formulated for 1.OM and 1.4M diameter antennas. As the formulation is based on currently available components, it is possible to design and fabricate the formulated mechanism without new hardware development. A preliminary specification for major components of formulated drives is also included in the report.

  9. Multifrequency Aperture-Synthesizing Microwave Radiometer System (MFASMR). Volume 1

    NASA Technical Reports Server (NTRS)

    Wiley, C. A.; Chang, M. U.

    1981-01-01

    Background material and a systems analysis of a multifrequency aperture - synthesizing microwave radiometer system is presented. It was found that the system does not exhibit high performance because much of the available thermal power is not used in the construction of the image and because the image that can be formed has a resolution of only ten lines. An analysis of image reconstruction is given. The system is compared with conventional aperture synthesis systems.

  10. COBE Differential Microwave Radiometer (DMR) data processing techniques

    NASA Technical Reports Server (NTRS)

    Jackson, P. D.; Smoot, G. F.; Bennett, C. L.; Aymon, J.; Backus, C.; Deamici, G.; Hinshaw, G.; Keegstra, P. B.; Kogut, A.; Lineweaver, C.

    1992-01-01

    The purpose of the Differential Microwave Radiometer (DMR) experiment on the Cosmic Background Explorer (COBE) satellite is to make whole-sky maps, at frequencies of 31.5, 53, and 90 GHz, of any departures of the Cosmic Microwave Background (CMB) from its mean value of 2.735 K. An elaborate software system is necessary to calibrate and invert the differential measurements, so as to make sky maps free from large scale systematic errors to levels less than a millionth of the CMB.

  11. COBE DMR results and implications. [Differential Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Smoot, George F.

    1992-01-01

    This lecture presents early results obtained from the first six months of measurements of the Cosmic Microwave Background (CMB) by Differential Microwave Radiometers (DMR) aboard COBE and discusses significant cosmological implications. The DMR maps show the dipole anisotropy and some galactic emission but otherwise a spatially smooth early universe. The measurements are sufficiently precise that we must pay careful attention to potential systematic errors. Maps of galactic and local emission such as those produced by the FIRAS and DIRBE instruments will be needed to identify foregrounds from extragalactic emission and thus to interpret the results in terms of events in the early universe. The current DMR results are significant for Cosmology.

  12. Microwave Radiometer/Scatterometer and Altimeter - Skylab Experiment S193

    NASA Technical Reports Server (NTRS)

    1970-01-01

    This 1970 photograph shows Skylab's Microwave Radiometer/Scatterometer and Altimeter, one of the major components for an Earth Resources Experiment Package (EREP). It was designed to study varying ocean surface, soil erosion, sea and lake ice, snow cover, seasonal vegetational changes, flooding, rainfall and soil types. The overall purpose of the EREP was to test the use of sensors that operated in the visible, infrared, and microwave portions of the electromagnetic spectrum to monitor and study Earth resources. The Marshall Space Flight Center had program management responsibility for the development of Skylab hardware and experiments.

  13. A network suitable microwave radiometer for operational monitoring of the cloudy atmosphere

    NASA Astrophysics Data System (ADS)

    Rose, Thomas; Crewell, Susanne; Löhnert, Ulrich; Simmer, Clemens

    2005-05-01

    The implementation of an operational network of microwave radiometers is presently hampered by the cost and complexity of the available instruments. For this reason, the definition and design of a low-cost microwave radiometer suitable for automatic, high-quality observations of liquid water path (LWP) were one objective of the BALTEX cloud liquid water network: CLIWA-NET. In the course of the project, it turned out that a full profiling radiometer with 14 channels can be produced at only about 30% higher cost than a classical dual-channel IWV/LWP radiometer. The profiling capability allows simultaneous observations of LWP and the lower tropospheric (0-5 km) humidity and temperature profiles with a temporal resolution of less than 10 s and a vertical resolution from 100 m to 1 km in the planetary boundary layer depending on height and atmospheric conditions. The latter is possible due to an elevation scan capability and by the implementation of a new filter bank design. The radiometer has several additional sensors (temperature, humidity, pressure, rain detector and GPS) which guarantee, together with a flexible software package, the operational performance of the system with maintenance intervals of about every 3 months. The performance of the first prototype has been verified during a 3-week campaign at Cabauw, The Netherlands.

  14. Use of a cloud-sensing radar and a microwave radiometer as a stratus cloud profiler

    SciTech Connect

    Frisch, A.S.; Fairall, C.W.; Snider, J.B.

    1994-12-31

    Remote sensors such as radar offer an alternate approach to the study of could and drizzle properties. Combining stratus cloud measurements from a K{sub {alpha}}-band radar and microwave radiometer can give profiles of liquid water and droplet distribution. In addition, in drizzle, the radar measurements can be used to estimate drizzle parameters such as number concentration, liquid water, and droplet distribution.

  15. Aperture synthesis for microwave radiometers in space

    NASA Technical Reports Server (NTRS)

    Levine, D. M.; Good, J. C.

    1983-01-01

    A technique is described for obtaining passive microwave measurements from space with high spatial resolution for remote sensing applications. The technique involves measuring the product of the signal from pairs of antennas at many different antenna spacings, thereby mapping the correlation function of antenna voltage. The intensity of radiation at the source can be obtained from the Fourier transform of this correlation function. Theory is presented to show how the technique can be applied to large extended sources such as the Earth when observed from space. Details are presented for a system with uniformly spaced measurements.

  16. A concept for global crop forecasting. [using microwave radiometer satellites

    NASA Technical Reports Server (NTRS)

    Lovelace, U. M.; Wright, R. L.

    1983-01-01

    The mission, instrumentation, and design concepts for microwave radiometer satellites for continuous crop condition forecasting and monitoring on a global basis are described. Soil moisture affects both crop growth and the dielectric properties of the soil, and can be quantified by analysis of reflected radiance passively received by orbiting spacecraft. A dedicated satellite reading a swath 200 km across, with 1 km and 1 K temperature resolution, could track the time-varying changes of solid moisture, sea ice, and water surface temperature. Launched by the Shuttle into an interim orbit, a boost would place the satellite in a 400 or 700 km orbit. Resolution requirements indicate a 45-725 m diam antenna, with 70 dB gain, operating at frequencies of 1.08, 2.03, and 4.95 GHz to ensure atmospheric transparency. Alternative structural concepts include either double-layer tetrahedral or single-layer geodesic trusses as the basic structural members. An analysis of the electrostatic positioning of the parabolic antenna membrane is outlined.

  17. Design and Development of the SMAP Microwave Radiometer Electronics

    NASA Technical Reports Server (NTRS)

    Piepmeier, Jeffrey R.; Medeiros, James J.; Horgan, Kevin A.; Brambora, Clifford K.; Estep, Robert H.

    2014-01-01

    The SMAP microwave radiometer will measure land surface brightness temperature at L-band (1413 MHz) in the presence of radio frequency interference (RFI) for soil moisture remote sensing. The radiometer design was driven by the requirements to incorporate internal calibration, to operate synchronously with the SMAP radar, and to mitigate the deleterious effects of RFI. The system design includes a highly linear super-heterodyne microwave receiver with internal reference loads and noise sources for calibration and an innovative digital signal processor and detection system. The front-end comprises a coaxial cable-based feed network, with a pair of diplexers and a coupled noise source, and radiometer front-end (RFE) box. Internal calibration is provided by reference switches and a common noise source inside the RFE. The RF back-end (RBE) downconverts the 1413 MHz channel to an intermediate frequency (IF) of 120 MHz. The IF signals are then sampled and quantized by high-speed analog-to-digital converters in the radiometer digital electronics (RDE) box. The RBE local oscillator and RDE sampling clocks are phase-locked to a common reference to ensure coherency between the signals. The RDE performs additional filtering, sub-band channelization, cross-correlation for measuring third and fourth Stokes parameters, and detection and integration of the first four raw moments of the signals. These data are packetized and sent to the ground for calibration and further processing. Here we discuss the novel features of the radiometer hardware particularly those influenced by the need to mitigate RFI.

  18. The Use of Rotating Shadowband Radiometers and Microwave Radiometers to Obtain Cloud Properties in Arctic Environments

    SciTech Connect

    Barnard, James C. ); Liljegren, James C.; Min, Qilong; Doran, J Christopher )

    2001-01-01

    In this paper we discuss the use of rotating shadowband radiometers and microwave radiometers to find shortwave cloud optical depth and cloud effective radius at two Arctic sites. These sites are the SHEBA ice camp site (a field study undertaken in 1997 and 1998) and the ARM Barrow (AK) site. Special measures are necessary to process the data from the SHEBA site to account for the harsh environment in which the instruments reside. The analysis shows that, over the summer of 1998, the median cloud optical depth at the SHEBA site is greater than the median cloud optical depth at the Barrow site. The cloud droplet effective radius is less at the SHEBA site than the Barrow site.

  19. The Water Vapour Radiometer at Effelsberg

    NASA Astrophysics Data System (ADS)

    Roy, A. L.; Teuber, U.; Keller, R.

    We have installed a scanning 18 GHz to 26 GHz water vapour radiometer on the focus cabin of the Effelsberg 100 m telescope for tropospheric phase, delay and opacity correction during high-frequency VLBI observations. It is based on the design by Tahmoush & Rogers (2000) but with noise injection for calibration, weather-proof housing, and temperature stabilization. The radiometer is delivering data into an archive since July 2003, from which they are available for download. The data will be delivered automatically to PIs of EVN experiments in a calibration table attached by the EVN calibration pipeline. This paper describes the radiometer and its performance.

  20. Diurnal Difference Vegetation Water Content (ddVWC) of Advance Microwave Scanning Radiometer-Earth Observing System (AMSR-E) for assessment of crop water stress at regional level

    NASA Astrophysics Data System (ADS)

    Chakraborty, A.; Sesha Sai, M. V. R.

    2014-11-01

    Advance Microwave Scanning Radiometer - Earth Observing System (AMSR-E) derived Vegetation Water Content (VWC) at predawn (01:30 LST, descending pass) and afternoon (13:30 LST; ascending pass) were used to assess crop water stress condition over the selected meteorological subdivisions of India. The temporal profile of Normalized Difference Vegetation Index (NDVI) was used to study the progression of crop growth. The Diurnal Difference Vegetation Water Content (ddVWC) was found to be sensitive to rainfall patterns (wet/dry spell) particularly in moderate to full crop cover condition (NDVI > 0.4). The ddVWC was found to be significantly (p = 0.05) correlated with the rainfall over the rainfed regions. The ddVWC was further characterized to represent different categories of crop water stress considering irrigated flooded rice crop as a benchmark. Inter year comparative analysis of temporal variations of the ddVWC revealed its capability to differentiate normal (2005) and sub-normal years (2008 and 2009) in term of intensity and persistence of crop water stress. Spatio-temporal patterns of ddVWC could capture regional progression of crop water stress at high temporal resolution in near real time.

  1. Data processing for the DMSP microwave radiometer system

    NASA Technical Reports Server (NTRS)

    Rigone, J. L.; Stogryn, A. P.

    1977-01-01

    A software program was developed and tested to process microwave radiometry data to be acquired by the microwave sensor (SSM/T) on the Defense Meteorological Satellite Program spacecraft. The SSM/T 7-channel microwave radiometer and systems data will be data-linked to Air Force Global Weather Central (AFGWC) where they will be merged with ephemeris data prior to product processing for use in the AFGWC upper air data base (UADB). The overall system utilizes an integrated design to provide atmospheric temperature soundings for global applications. The fully automated processing at AFGWC was accomplished by four related computer processor programs to produce compatible UADB soundings, evaluate system performance, and update the a priori developed inversion matrices. Tests with simulated data produced results significantly better than climatology.

  2. Estimating atmospheric temperature profile by an airborne microwave radiometer

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Xu, Jian; Kenntner, Mareike; Schreier, Franz; Doicu, Adrian

    2017-04-01

    As the rising atmospheric issues such as climate change, air pollution, and ozone depletion have extracted extensive attraction worldwide, observing and modeling of atmospheric quantities becomes critical to our understanding of the environment. This work focuses on the performance of an airborne passive microwave radiometer called MTP (Microwave Temperature Profiler). We aim to obtain vertically distributed atmospheric temperature from intensities measured by the instrument in terms of three frequencies and ten viewing angles. A retrieval program TIRAMISU (Temperature InveRsion Algorithm for MIcrowave SoUnding) has been utilized for processing the MTP data. To solve this severely ill-posed inverse problem, an analysis of different ways of constructing the penalty term onto the Tikhonov-type objective function is conducted. This numerical analysis can help us to better understand pros and cons of these regularization methods and to investigate the measurement capabilities of MTP.

  3. Columnar water vapor retrievals from multifilter rotating shadowband radiometer data

    SciTech Connect

    Alexandrov, Mikhail; Schmid, Beat; Turner, David D.; Cairns, Brian; Oinas, Valdar; Lacis, Andrew A.; Gutman, S.; Westwater, Ed R.; Smirnov, A.; Eilers, J.

    2009-01-26

    The Multi-Filter Rotating Shadowband Radiometer (MFRSR) measures direct and diffuse irradiances in the visible and near IR spectral range. In addition to characteristics of atmospheric aerosols, MFRSR data also allow retrieval of precipitable water vapor (PWV) column amounts, which are determined from the direct normal irradiances in the 940 nm spectral channel. The HITRAN 2004 spectral database was used in our retrievals to model the water vapor absorption. We present a detailed error analysis describing the influence of uncertainties in instrument calibration and spectral response, as well as those in available spectral databases, on the retrieval results. The results of our PWV retrievals from the Southern Great Plains (SGP) site operated by the DOE Atmospheric Radiation Measurement (ARM) Program were compared with correlative standard measurements by Microwave Radiometers (MWRs) and a Global Positioning System (GPS) water vapor sensor, as well as with retrievals from other solar radiometers (AERONET’s CIMEL, AATS-6). Some of these data are routinely available at the SGP’s Central Facility, however, we also used measurements from a wider array of instrumentation deployed at this site during the Water Vapor Intensive Observation Period (WVIOP2000) in September – October 2000. The WVIOP data show better agreement between different solar radiometers or between different microwave radiometers (both groups showing relative biases within 4%) than between these two groups of instruments, with MWRs values being consistently higher (up to 14%) than those from solar instruments. We also demonstrate the feasibility of using MFRSR network data for creation of 2D datasets comparable with the MODIS satellite water vapor product.

  4. The Seasat scanning multichannel microwave radiometer /SMMR/ - Instrument description and performance

    NASA Technical Reports Server (NTRS)

    Njoku, E. G.; Stacey, J. M.; Barath, F. T.

    1980-01-01

    The scanning multichannel microwave radiometer (SMMR) is an imaging 5-frequency radiometer flown on the Seasat and Nimbus-7 earth satellites launched in 1978. It measures dual-polarized microwave radiances from the earth's atmosphere and surface, primarily for the purpose of deriving global and nearly all-weather measurements of sea surface temperature, wind speed, and atmospheric liquid water and water vapor. This paper describes the SMMR instrument and its calibration, antenna pattern measurements, and data processing procedures. Analysis of early data from the Seasat SMMR shows that the expected engineering performance in flight was achieved, and the measurement of sea surface temperature and wind speed with accuracies of 1.5 K and 2 m/s, respectively, may be achievable once the geophysical data processing algorithms and analysis have been completed.

  5. The utilization of spaceborne microwave radiometers for monitoring snowpack properties. [United States and Canada

    NASA Technical Reports Server (NTRS)

    Rango, A.; Chang, A. T. C.; Foster, J. L.

    1980-01-01

    Snow accumulation and depletion at specific locations can be monitored from space by observing related variations in microwave brightness temperatures. Using vertically and horizontally polarized brightness temperatures from the Nimbus 6 electrically scanning microwave radiometer, a discriminant function can be used to separate snow from no snow areas and map snowcovered area on a continental basis. For dry snow conditions on the Canadian high plains, significant relationships between snow depth or water equivalent and microwave brightness temperature were developed which could permit remote determination of these snow properties after acquisition of a wider range of data. The presence of melt water in the snowpack causes a marked increase in brightness temperature which can be used to predict snowpack priming and timing of runoff. As the resolutions of satellite microwave sensors improve the application of these results to snow hydrology problems should increase.

  6. The utilization of spaceborne microwave radiometers for monitoring snowpack properties. [United States and Canada

    NASA Technical Reports Server (NTRS)

    Rango, A.; Chang, A. T. C.; Foster, J. L.

    1980-01-01

    Snow accumulation and depletion at specific locations can be monitored from space by observing related variations in microwave brightness temperatures. Using vertically and horizontally polarized brightness temperatures from the Nimbus 6 electrically scanning microwave radiometer, a discriminant function can be used to separate snow from no snow areas and map snowcovered area on a continental basis. For dry snow conditions on the Canadian high plains, significant relationships between snow depth or water equivalent and microwave brightness temperature were developed which could permit remote determination of these snow properties after acquisition of a wider range of data. The presence of melt water in the snowpack causes a marked increase in brightness temperature which can be used to predict snowpack priming and timing of runoff. As the resolutions of satellite microwave sensors improve the application of these results to snow hydrology problems should increase.

  7. Development of the Microwave Radiometer Technology Acceleration (MiRaTA) CubeSat for all-weather atmospheric sounding

    NASA Astrophysics Data System (ADS)

    Cahoy, K.; Blackwell, W. J.; Marinan, A.; Bishop, R. L.; Leslie, V. V.; Shields, M.; Marlow, W.; Kennedy, A.

    2015-12-01

    The Microwave Radiometer Technology Acceleration (MiRaTA) is a 3U CubeSat mission sponsored by the NASA Earth Science Technology Office (ESTO). The science payload on MiRaTA consists of a tri-band microwave radiometer and GPS radio occultation (GPSRO) experiment. The microwave radiometer takes measurements of allweather temperature (V-band, 52-58 GHz), water vapor, and cloud ice (G-band, 175-191 & 207 GHz) to provide key contributions toward improved weather forecasting. The GPSRO experiment, called the Compact TEC (Total Electron Count)/Atmosphere GPS Sensor (CTAGS) measures profiles of temperature and pressure in the upper neutral atmosphere and electron density in the ionosphere. The MiRaTA mission will validate new technologies in both passive microwave radiometry and GPS radio occultation: (1) new ultra-compact and low-power technology for multi-channel and multi-band passive microwave radiometers, and (2) new GPS receiver and patch antenna array technology for both neutral atmosphere and ionospheric GPS radio occultation retrieval on a nanosatellite. In addition, MiRaTA will test (3) a new approach to spaceborne microwave radiometer calibration using adjacent GPSRO measurements.

  8. Thermoelectric temperature control system for the pushbroom microwave radiometer (PBMR)

    NASA Astrophysics Data System (ADS)

    Dillon-Townes, L. A.; Averill, R. D.

    1984-06-01

    A closed loop thermoelectric temperature control system is developed for stabilizing sensitive RF integrated circuits within a microwave radiometer to an accuracy of + or - 0.1 C over a range of ambient conditions from -20 C to +45 C. The dual mode (heating and cooling) control concept utilizes partial thermal isolation of the RF units from an instrument deck which is thermally controlled by thermoelectric coolers and thin film heaters. The temperature control concept is simulated with a thermal analyzer program (MITAS) which consists of 37 nodes and 61 conductors. A full scale thermal mockup is tested in the laboratory at temperatures of 0 C, 21 C, and 45 C to confirm the validity of the control concept. A flight radiometer and temperature control system is successfully flight tested on the NASA Skyvan aircraft.

  9. Thermoelectric temperature control system for the pushbroom microwave radiometer (PBMR)

    NASA Technical Reports Server (NTRS)

    Dillon-Townes, L. A.; Averill, R. D.

    1984-01-01

    A closed loop thermoelectric temperature control system is developed for stabilizing sensitive RF integrated circuits within a microwave radiometer to an accuracy of + or - 0.1 C over a range of ambient conditions from -20 C to +45 C. The dual mode (heating and cooling) control concept utilizes partial thermal isolation of the RF units from an instrument deck which is thermally controlled by thermoelectric coolers and thin film heaters. The temperature control concept is simulated with a thermal analyzer program (MITAS) which consists of 37 nodes and 61 conductors. A full scale thermal mockup is tested in the laboratory at temperatures of 0 C, 21 C, and 45 C to confirm the validity of the control concept. A flight radiometer and temperature control system is successfully flight tested on the NASA Skyvan aircraft.

  10. Limits of Precipitation Detection from Microwave Radiometers and Sounders

    NASA Astrophysics Data System (ADS)

    Munchak, S. J.; Skofronick-Jackson, G.; Johnson, B. T.

    2012-04-01

    The Global Precipitation Measurement (GPM) mission will unify and draw from numerous microwave conical scanning imaging radiometers and cross-track sounders, many of which already in operation, to provide near real-time precipitation estimates worldwide at 3-hour intervals. Some of these instruments were designed for primary purposes unrelated to precipitation remote sensing. Therefore it is worthwhile to evaluate the strengths and weaknesses of each set of channels with respect to precipitation detection to fully understand their role in the GPM constellation. The GPM radiometer algorithm will use an observationally-based Bayesian retrieval with common databases of precipitation profiles for all sensors. Since these databases are still under development and will not be truly complete until the GPM core satellite has completed at least one year of dual-frequency radar observations, a screening method based upon retrieval of non-precipitation parameters related to the surface and atmospheric state is used in this study. A cost function representing the departure of modeled radiances from their observed values plus the departure of surface and atmospheric parameters from the TELSEM emissivity atlas and MERRA reanalysis is used as an indicator of precipitation. Using this method, two datasets are used to evaluate precipitation detection: One year of matched AMSR-E and AMSU-B/MHS overpasses with CloudSat used as validation globally; and SSMIS overpasses over the United States using the National Mosaic and QPE (NMQ) as validation. The Heidke Skill Score (HSS) is used as a metric to evaluate detection skill over different surfaces, seasons, and across different sensors. Non-frozen oceans give the highest HSS for all sensors, followed by bare land and coasts, then snow-covered land and sea ice. Negligible skill is present over ice sheets. Sounders tend to have higher skill than imagers over complex surfaces (coast, snow, and sea ice), whereas imagers have higher skill

  11. A One-Dimensional Synthetic-Aperture Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Doiron, Terence; Piepmeier, Jeffrey

    2010-01-01

    A proposed one-dimensional synthetic- aperture microwave radiometer could serve as an alternative to either the two-dimensional synthetic-aperture radiometer described in the immediately preceding article or to a prior one-dimensional one, denoted the Electrically Scanned Thinned Array Radiometer (ESTAR), mentioned in that article. The proposed radiometer would operate in a pushbroom imaging mode, utilizing (1) interferometric cross-track scanning to obtain cross-track resolution and (2) the focusing property of a reflector for along-track resolution. The most novel aspect of the proposed system would be the antenna (see figure), which would include a cylindrical reflector of offset parabolic cross section. The reflector could be made of a lightweight, flexible material amenable to stowage and deployment. Other than a stowage/deployment mechanism, the antenna would not include moving parts, and cross-track scanning would not entail mechanical rotation of the antenna. During operation, the focal line, parallel to the cylindrical axis, would be oriented in the cross-track direction, so that placement of receiving/radiating elements at the focal line would afford the desired along-track resolution. The elements would be microwave feed horns sparsely arrayed along the focal line. The feed horns would be oriented with their short and long cross-sectional dimensions parallel and perpendicular, respectively, to the cylindrical axis to obtain fan-shaped beams having their broad and narrow cross-sectional dimensions parallel and perpendicular, respectively, to the cylindrical axis. The interference among the beams would be controlled in the same manner as in the ESTAR to obtain along-cylindrical- axis (cross-track) resolution and cross-track scanning.

  12. Precipitation from the GPM Microwave Imager and Constellation Radiometers

    NASA Astrophysics Data System (ADS)

    Kummerow, C. D.

    2012-12-01

    Satellite precipitation retrievals are fundamentally underconstrained requiring either implicit or explicit a-prior information to constrain the solutions. The radiometer algorithm being designed for the GPM core and constellation satellites makes this a-priori information explicit in the form of an a-priori database of possible rain structures and a Bayesian retrieval scheme. The a-priori database has its heritage in the TRMM satellite which ushered in an era of active/passive microwave retrievals. Because the output from such retrievals is physically consistent with the rainfall seen by the radar and the brightness temperatures seen by the radiometer, they are ideally suited for the a-priori database. This approach will be repeated for the Global Precipitation Mission, now scheduled for launch in February 2014. Its core satellite will carry a dual frequency radar and state of the art microwave radiometer. This combination of sensors, and the accompanying multi-sensor algorithm will provide a basis for creating the a-priori database for the radiometer only retrievals that is applicable not only to the wider swath of the GPM Microwave Imager (GMI), but to all the constellation radiometers. This talk will present the pre-launch synthesis of various satellite systems to simulate the core satellite retrieval necessary to have a reasonably robust database in place for the launch of the GPM core satellite. The talk will then focus on the implementation of the algorithm itself. This algorithm has a number of advances over previous versions. Most importantly, is the absence of screening routines that previously identified pixels as being raining or non-raining. This was particularly important over land where the surface could easily be mistaken for ice scattering in raining clouds. By having much better controls over the land surface and land surface emissivities, along with robust a-priori databases, the new algorithm relies completely on the Tb signature to determine

  13. Systems design and analysis of the microwave radiometer spacecraft

    NASA Technical Reports Server (NTRS)

    Garrett, L. B.

    1981-01-01

    Systems design and analysis data were generated for microwave radiometer spacecraft concept using the Large Advanced Space Systems (LASS) computer aided design and analysis program. Parametric analyses were conducted for perturbations off the nominal-orbital-altitude/antenna-reflector-size and for control/propulsion system options. Optimized spacecraft mass, structural element design, and on-orbit loading data are presented. Propulsion and rigid-body control systems sensitivities to current and advanced technology are established. Spacecraft-induced and environmental effects on antenna performance (surface accuracy, defocus, and boresight off-set) are quantified and structured material frequencies and modal shapes are defined.

  14. COBE Differential Microwave Radiometers - Preliminary systematic error analysis

    NASA Technical Reports Server (NTRS)

    Kogut, A.; Smoot, G. F.; Bennett, C. L.; Wright, E. L.; Aymon, J.; De Amici, G.; Hinshaw, G.; Jackson, P. D.; Kaita, E.; Keegstra, P.

    1992-01-01

    The techniques available for the identification and subtraction of sources of dynamic uncertainty from data of the Differential Microwave Radiometer (DMR) instrument aboard COBE are discussed. Preliminary limits on the magnitude in the DMR 1 yr maps are presented. Residual uncertainties in the best DMR sky maps, after correcting the raw data for systematic effects, are less than 6 micro-K for the pixel rms variation, less than 3 micro-K for the rms quadruple amplitude of a spherical harmonic expansion, and less than 30 micro-(K-squared) for the correlation function.

  15. COBE Differential Microwave Radiometers - Preliminary systematic error analysis

    NASA Astrophysics Data System (ADS)

    Kogut, A.; Smoot, G. F.; Bennett, C. L.; Wright, E. L.; Aymon, J.; de Amici, G.; Hinshaw, G.; Jackson, P. D.; Kaita, E.; Keegstra, P.; Lineweaver, C.; Loewenstein, K.; Rokke, L.; Tenorio, L.; Boggess, N. W.; Cheng, E. S.; Gulkis, S.; Hauser, M. G.; Janssen, M. A.; Kelsall, T.; Mather, J. C.; Meyer, S.; Moseley, S. H.; Murdock, T. L.; Shafer, R. A.; Silverberg, R. F.; Weiss, R.; Wilkinson, D. T.

    1992-12-01

    The techniques available for the identification and subtraction of sources of dynamic uncertainty from data of the Differential Microwave Radiometer (DMR) instrument aboard COBE are discussed. Preliminary limits on the magnitude in the DMR 1 yr maps are presented. Residual uncertainties in the best DMR sky maps, after correcting the raw data for systematic effects, are less than 6 micro-K for the pixel rms variation, less than 3 micro-K for the rms quadruple amplitude of a spherical harmonic expansion, and less than 30 micro-(K-squared) for the correlation function.

  16. Global atmospheric temperature anomaly monitoring with passive microwave radiometers

    NASA Technical Reports Server (NTRS)

    Spencer, Roy W.; Christy, John R.

    1990-01-01

    The potential of microwave sounding units (MSU) for augmenting the surface-based thermometer record by providing a measurement representing a significant depth of the troposphere is considered. These radiometers measure the thermal emission by molecular oxygen in the atmosphere at different spectral intervals in the oxygen absorption complex near 60 GHz. Brightness temperature variations measured by NOAA-6 and NOAA-7 MSUs during a near-two year period are analyzed and compared with monthly averaged surface air temperature data. It is demonstrated that MSUs, while of limited use for vertical profiling of the atmosphere, provide stable measurements of vertically average atmospheric temperatures, centered at a constant pressure level.

  17. Clear air turbulence avoidance using an airborne microwave radiometer

    NASA Technical Reports Server (NTRS)

    Gary, B. L.

    1984-01-01

    The avoidance of Clear Air Turbulence (CAT) is theoretically possible by selecting flight levels that are a safe distance from the tropopause and inversion layers. These favored sites for CAT generation can be located by an 'airborne microwave radiometer' (AMR) passive sensor system that measures altitude temperature profiles. A flight evaluation of the AMR sensor shows that most CAT could be avoided by following sensor-based advisories. Some limitations still exist for any hypothetical use of the sensor. The principal need is to augment the sensor's 'where' advisories to include useful 'when' forecasts.

  18. Preliminary separation of galactic and cosmic microwave emission for the COBE Differential Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Bennet, C. L.; Smoot, G. F.; Hinshaw, G.; Wright, E. L.; Kogut, A.; De Amici, G.; Meyer, S. S.; Weiss, R.; Wilkinson, D. T.; Gulkis, S.

    1992-01-01

    Preliminary models of microwave emission from the Milky Way Galaxy based on COBE and other data are constructed for the purpose of distinguishing cosmic and Galactic signals. Differential Microwave Radiometer (DMR) maps, with the modeled Galactic emission removed, are fitted for a quadrupole distribution. Autocorrelation functions for individual Galactic components are presented. When Galactic emission is removed from the DMR data, the residual fluctuations are virtually unaffected, and therefore they are not dominated by any known Galactic emission component.

  19. Airborne Demonstration of Microwave and Wide-Band Millimeter-Wave Radiometers to Provide High-Resolution Wet-Tropospheric Path Delay Corrections for Coastal and Inland Water Altimetry

    NASA Astrophysics Data System (ADS)

    Reising, Steven; Kangaslahti, Pekka; Tanner, Alan; Padmanabhan, Sharmila; Montes, Oliver; Parashare, Chaitali; Bosch-Lluis, Xavier; Hadel, Victoria; Johnson, Thaddeus; Brown, Shannon; Khayatian, Behrouz; Dawson, Douglas; Gaier, Todd; Razavi, Behzad

    2014-05-01

    Current satellite ocean altimeters include nadir-viewing, co-located 18-34 GHz microwave radiometers to measure wet-tropospheric path delay. Due to the size of the surface instantaneous fields of view (IFOV) at these frequencies, the accuracy of wet path retrievals is substantially degraded near coastlines, and retrievals are not provided over land. Retrievals are flagged as not useful within approximately 40 km of the world's coastlines. A viable approach to improve their capability is to add wide-band high-frequency millimeter-wave window channels in the 90-180 GHz band, thereby achieving finer spatial resolution for a limited antenna size. In this context, the upcoming NASA/CNES/CSA Surface Water and Ocean Topography (SWOT) mission is in formulation and planned for launch in late 2020. The primary objectives of SWOT are to characterize ocean mesoscale and sub-mesoscale processes on 10-km and larger scales in the global oceans and provide measurements of the global water storage in inland surface water bodies and the flow rate of rivers. Therefore, an important new science objective of SWOT is to transition satellite altimetry from the open ocean into the coastal zone and over inland water. The addition of 90-180 GHz millimeter-wave window-channel radiometers to current Jason-class 18-34 GHz radiometers is expected to improve retrievals of wet-tropospheric delay in coastal areas and to enhance the potential for over-land retrievals. In 2012 the Ocean Surface Topography Science Team Meeting recommended to add high-frequency millimeter-wave radiometers to the Jason Continuity of Service (CS) mission. To reduce the risks of wet-tropospheric path delay measurement over coastal areas and inland water bodies, we have designed, developed and fabricated a new airborne radiometer, combining three high-frequency millimeter-wave window channels at 90, 130 and 168 GHz, along with Jason-series microwave channels at 18.7, 23.8 and 34.0 GHz, and validation channels sounding

  20. Mission definition for a large-aperture microwave radiometer spacecraft

    NASA Technical Reports Server (NTRS)

    Keafer, L. S., Jr.

    1981-01-01

    An Earth-observation measurements mission is defined for a large-aperture microwave radiometer spacecraft. This mission is defined without regard to any particular spacecraft design concept. Space data application needs, the measurement selection rationale, and broad spacecraft design requirements and constraints are described. The effects of orbital parameters and image quality requirements on the spacecraft and mission performance are discussed. Over the land the primary measurand is soil moisture; over the coastal zones and the oceans important measurands are salinity, surface temperature, surface winds, oil spill dimensions and ice boundaries; and specific measurement requirements have been selected for each. Near-all-weather operation and good spatial resolution are assured by operating at low microwave frequencies using an extremely large aperture antenna in a low-Earth-orbit contiguous mapping mode.

  1. COBE Differential Microwave Radiometers - Instrument design and implementation

    NASA Technical Reports Server (NTRS)

    Smoot, G.; Bennett, Charles; Weber, R.; Maruschak, John; Ratliff, Roger; Janssen, M.

    1990-01-01

    Differential Microwave Radiometers (DMRs) at frequencies of 31.5, 53, and 90 GHz have been designed and built to map the large angular scale variations in the brightness temperature of the cosmic microwave background radiation. The instrument is being flown aboard NASA's Cosmic Background Explorer (COBE) satellite, launched on November 18, 1989. Each receiver input is switched between two antennas pointing 60 deg apart on the sky. The satellite is in near-polar orbit with the orbital plane precessing at 1 deg per day, causing the beams to scan the entire sky in 6 months. In 1 year of observation, the instruments are capable of mapping the sky to an rms sensitivity of 0.1 mK per 7 deg field of view. The mission and the instrument have been carefully designed to minimize the need for systematic corrections to the data.

  2. Low-frequency microwave radiometer for N-ROSS

    NASA Technical Reports Server (NTRS)

    Hollinger, J. P.; Lo, R. C.

    1985-01-01

    The all weather, global determination of sea surface temperature (SST) has been identified as a requirement needed to support naval operations. The target SST accuracy is + or - 1.0 K with a surface resolution of 10 km. Investigations of the phenomenology and technology of remote passive microwave sensing of the ocean environment over the past decade have demonstrated that this objective is presently attainable. Preliminary specification and trade off studies were conducted to define the frequency, polarization, scan geometry, antenna size, and other esstential parameters of the low frequency microwave radiometer (LFMR). It will be a dual polarized, dual frequency system at 5.2 and 10.4 GHz using a 4.9 meter deployable mesh surface antenna. It is to be flown on the Navy-Remote Ocean Sensing System (N-ROSS) satellite scheduled to be launched in late 1988.

  3. Measurement of oceanic wind vector using satellite microwave radiometers

    NASA Technical Reports Server (NTRS)

    Wentz, Frank J.

    1992-01-01

    A feasibility study of deriving both a wind speed and direction from microwave radiometer measurements of the ocean is presented. The study was based on the Special Sensor Microwave/Imager (SSM/I) measurements in conjunction with buoy reports from the National Data Buoy Center. It was found that the SSM/I minus the buoy wind speed difference is correlated with wind direction due to a wind direction signal in the brightness temperatures. When this wind direction signal is removed the rms difference between the SSM/I and buoy winds reduces to 1.3 m/s. The wind direction signal was used to make global, low-resolution maps of the monthly mean oceanic wind vector.

  4. DSN water vapor radiometer development: Recent work

    NASA Technical Reports Server (NTRS)

    Slobin, S. D.; Batelaan, P. D.

    1977-01-01

    A water vapor radiometer (WVR) was developed which measures the atmospheric noise temperature at two different frequencies. These noise temperatures are used in empirical-theoretical equations which yield tropospheric range delay, in centimeters, through the atmosphere along the beam of the WVR. This range correction is then applied to measurements concerning spacecraft range and to very long baseline interferometry determinations.

  5. Millimeter-wave imaging radiometer data processing and development of water vapor retrieval algorithms

    NASA Technical Reports Server (NTRS)

    Chang, L. Aron

    1995-01-01

    This document describes the current status of Millimeter-wave Imaging Radiometer (MIR) data processing and the technical development of the first version of a water vapor retrieval algorithm. The algorithm is being used by NASA/GSFC Microwave Sensors Branch, Laboratory for Hydrospheric Processes. It is capable of a three dimensional mapping of moisture fields using microwave data from airborne sensor of MIR and spaceborne instrument of Special Sensor Microwave/T-2 (SSM/T-2).

  6. Towards the Temperature Retrieval by Using Airborne Microwave Radiometer Data

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    Atmospheric temperature is a key geophysical parameter when dealing with the atmosphere in areas such as climatology and meteorology. In general, thermal emissions of molecular lines (e.g. oxygen, carbon dioxide) can be used for the determination of the temperature profile. The superheterodyne radiometer MTP (Microwave Temperature Profiler) passively detects thermal emission from oxygen lines at a selection of frequencies between 55-60 GHz by scanning the atmosphere from near zenith to near nadir in the flight direction. The MTP instrument was designed to observe the vertical temperature distribution over the upper troposphere and lower stratosphere (UTLS) with a good temporal and spatial resolution. The instrument was originally developed at NASA's JPL and has been recently flown on DLR's HALO research aircraft.To estimate the temperature profile from microwave measurements (e.g. provided by MTP), the retrieval algorithm TIRAMISU (Temperature Inversion Algorithm for Microwave Sounding) has been developed at DLR and is currently used to conduct the data processing of the MTP measurements. This study performs the retrievals from the MTP data with a focus on the ML-CIRRUS mission. The corresponding retrieval performance is investigated by associated error characterization and external comparisons with other ground-based and satellite observations. These observations are important to resolve a variety of phenomena in the UTLS region and to potentially improve the temperature spaceborne soundings.

  7. MWR: Microwave Radiometer for the Juno Mission to Jupiter

    NASA Astrophysics Data System (ADS)

    Janssen, M. A.; Oswald, J. E.; Brown, S. T.; Gulkis, S.; Levin, S. M.; Bolton, S. J.; Allison, M. D.; Atreya, S. K.; Gautier, D.; Ingersoll, A. P.; Lunine, J. I.; Orton, G. S.; Owen, T. C.; Steffes, P. G.; Adumitroaie, V.; Bellotti, A.; Jewell, L. A.; Li, C.; Li, L.; Misra, S.; Oyafuso, F. A.; Santos-Costa, D.; Sarkissian, E.; Williamson, R.; Arballo, J. K.; Kitiyakara, A.; Ulloa-Severino, A.; Chen, J. C.; Maiwald, F. W.; Sahakian, A. S.; Pingree, P. J.; Lee, K. A.; Mazer, A. S.; Redick, R.; Hodges, R. E.; Hughes, R. C.; Bedrosian, G.; Dawson, D. E.; Hatch, W. A.; Russell, D. S.; Chamberlain, N. F.; Zawadski, M. S.; Khayatian, B.; Franklin, B. R.; Conley, H. A.; Kempenaar, J. G.; Loo, M. S.; Sunada, E. T.; Vorperion, V.; Wang, C. C.

    2017-03-01

    The Juno Microwave Radiometer (MWR) is a six-frequency scientific instrument designed and built to investigate the deep atmosphere of Jupiter. It is one of a suite of instruments on NASA's New Frontiers Mission Juno launched to Jupiter on August 5, 2011. The focus of this paper is the description of the scientific objectives of the MWR investigation along with the experimental design, observational approach, and calibration that will achieve these objectives, based on the Juno mission plan up to Jupiter orbit insertion on July 4, 2016. With frequencies distributed approximately by octave from 600 MHz to 22 GHz, the MWR will sample the atmospheric thermal radiation from depths extending from the ammonia cloud region at around 1 bar to pressure levels as deep as 1000 bars. The primary scientific objectives of the MWR investigation are to determine the presently unknown dynamical properties of Jupiter's subcloud atmosphere and to determine the global abundance of oxygen and nitrogen, present in the atmosphere as water and ammonia deep below their respective cloud decks. The MWR experiment is designed to measure both the thermal radiation from Jupiter and its emission-angle dependence at each frequency relative to the atmospheric local normal with high accuracy. The antennas at the four highest frequencies (21.9, 10.0, 5.2, and 2.6 GHz) have ˜12° beamwidths and will achieve a spatial resolution approaching 600 km near perijove. The antennas at the lowest frequencies (0.6 and 1.25 GHz) are constrained by physical size limitations and have 20° beamwidths, enabling a spatial resolution of as high as 1000 km to be obtained. The MWR will obtain Jupiter's brightness temperature and its emission-angle dependence at each point along the subspacecraft track, over angles up to 60° from the normal over most latitudes, during at least six perijove passes after orbit insertion. The emission-angle dependence will be obtained for all frequencies to an accuracy of better than one

  8. A statistical method to sense sea surface temperature from the Nimbus-7 scanning multichannel microwave radiometer

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Wang, I.

    1983-01-01

    Among the five channels in the Scanning Multichannel Microwave Radiometer (SMMR), the brightness temperature measured at 6.6 GHz vertical polarization is least affected by the atmospheric water vapor and liquid water in clouds or rain. Furthermore, as the undisturbed sea surface emissivity at 6.6 GHz is nearly constant over the temperature range 275 to 300 K, this channel has the best sensitivity to sea surface temperature (SST). The 6.6 GHz channel on SMMR is specifically chosen for these reasons to measure SST.

  9. A statistical method to sense sea surface temperature from the Nimbus-7 scanning multichannel microwave radiometer

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Wang, I.

    1983-01-01

    Among the five channels in the Scanning Multichannel Microwave Radiometer (SMMR), the brightness temperature measured at 6.6 GHz vertical polarization is least affected by the atmospheric water vapor and liquid water in clouds or rain. Furthermore, as the undisturbed sea surface emissivity at 6.6 GHz is nearly constant over the temperature range 275 to 300 K, this channel has the best sensitivity to sea surface temperature (SST). The 6.6 GHz channel on SMMR is specifically chosen for these reasons to measure SST.

  10. Advanced Passive Microwave Radiometer Technology for GPM Mission

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Im, Eastwood; Kummerow, Christian; Principe, Caleb; Ruf, Christoper; Wilheit, Thomas; Starr, David (Technical Monitor)

    2002-01-01

    An interferometer-type passive microwave radiometer based on MMIC receiver technology and a thinned array antenna design is being developed under the Instrument Incubator Program (TIP) on a project entitled the Lightweight Rainfall Radiometer (LRR). The prototype single channel aircraft instrument will be ready for first testing in 2nd quarter 2003, for deployment on the NASA DC-8 aircraft and in a ground configuration manner; this version measures at 10.7 GHz in a crosstrack imaging mode. The design for a two (2) frequency preliminary space flight model at 19 and 35 GHz (also in crosstrack imaging mode) has also been completed, in which the design features would enable it to fly in a bore-sighted configuration with a new dual-frequency space radar (DPR) under development at the Communications Research Laboratory (CRL) in Tokyo, Japan. The DPR will be flown as one of two primary instruments on the Global Precipitation Measurement (GPM) mission's core satellite in the 2007 time frame. The dual frequency space flight design of the ERR matches the APR frequencies and will be proposed as an ancillary instrument on the GPM core satellite to advance space-based precipitation measurement by enabling better microphysical characterization and coincident volume data gathering for exercising combined algorithm techniques which make use of both radar backscatter and radiometer attenuation information to constrain rainrate solutions within a physical algorithm context. This talk will discuss the design features, performance capabilities, applications plans, and conical/polarametric imaging possibilities for the LRR, as well as a brief summary of the project status and schedule.

  11. Island based radar and microwave radiometer measurements of stratus cloud parameters during the Atlantic Stratocumulus Transition Experiment (ASTEX)

    SciTech Connect

    Frisch, A.S.; Fairall, C.W.; Snider, J.B.; Lenshow, D.H.; Mayer, S.D.

    1996-04-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, simultaneous measurements were made with a vertically pointing cloud sensing radar and a microwave radiometer. The radar measurements are used to estimate stratus cloud drizzle and turbulence parameters. In addition, with the microwave radiometer measurements of reflectivity, we estimated the profiles of cloud liquid water and effective radius. We used radar data for computation of vertical profiles of various drizzle parameters such as droplet concentration, modal radius, and spread. A sample of these results is shown in Figure 1. In addition, in non-drizzle clouds, with the radar and radiometer we can estimate the verticle profiles of stratus cloud parameters such as liquid water concentration and effective radius. This is accomplished by assuming a droplet distribution with droplet number concentration and width constant with height.

  12. Calibrating ground-based microwave radiometers: Uncertainty and drifts

    NASA Astrophysics Data System (ADS)

    Küchler, N.; Turner, D. D.; Löhnert, U.; Crewell, S.

    2016-04-01

    The quality of microwave radiometer (MWR) calibrations, including both the absolute radiometric accuracy and the spectral consistency, determines the accuracy of geophysical retrievals. The Microwave Radiometer Calibration Experiment (MiRaCalE) was conducted to evaluate the performance of MWR calibration techniques, especially of the so-called Tipping Curve Calibrations (TCC) and Liquid Nitrogen Calibrations (LN2cal), by repeatedly calibrating a fourth-generation Humidity and Temperature Profiler (HATPRO-G4) that measures downwelling radiance between 20 GHz and 60 GHz. MiRaCalE revealed two major points to improve MWR calibrations: (i) the necessary repetition frequency for MWR calibration techniques to correct drifts, which ensures stable long-term measurements; and (ii) the spectral consistency of control measurements of a well known reference is useful to estimate calibration accuracy. Besides, we determined the accuracy of the HATPRO's liquid nitrogen-cooled blackbody's temperature. TCCs and LN2cals were found to agree within 0.5 K when observing the liquid nitrogen-cooled blackbody with a physical temperature of 77 K. This agreement of two different calibration techniques suggests that the brightness temperature of the LN2 cooled blackbody is accurate within at least 0.5 K, which is a significant reduction of the uncertainties that have been assumed to vary between 0.6 K and 1.5 K when calibrating the HATPRO-G4. The error propagation of both techniques was found to behave almost linearly, leading to maximum uncertainties of 0.7 K when observing a scene that is associated with a brightness temperature of 15 K.

  13. Ground registration of data from an airborne Multifrequency Microwave Radiometer (MfMR). [Colby, Kansas

    NASA Technical Reports Server (NTRS)

    Richter, J. C. (Principal Investigator)

    1981-01-01

    The agricultural soil moisture experiment was conducted near Colby, Kansas, in July and August 1978. A portion of the data collected was taken with a five band microwave radiometer. A method of locating the radiometer footprints with respect to a ground based coordinate system is documented. The procedure requires that the airplane's flight parameters along with aerial photography be acquired simultaneously with the radiometer data. The software which documented reads in data from the precision radiation thermometer (PRT Model 5) and attaches the scene temperature to the corresponding multifrequency microwave radiometer data. Listings of the programs used in the registration process are included.

  14. Soil Moisture Active Passive (SMAP) L-Band Microwave Radiometer Post-Launch Calibration

    NASA Technical Reports Server (NTRS)

    Peng, Jinzheng; Piepmeier, Jeffrey R.; Misra, Sidharth; Dinnat, Emmanuel P.; Hudson, Derek; Le Vine, David M.; De Amici, Giovanni; Mohammed, Priscilla N.; Yueh, Simon H.; Meissner, Thomas

    2016-01-01

    The SMAP microwave radiometer is a fully-polarimetric L-band radiometer flown on the SMAP satellite in a 6 AM/ 6 PM sun-synchronous orbit at 685 km altitude. Since April, 2015, the radiometer is under calibration and validation to assess the quality of the radiometer L1B data product. Calibration methods including the SMAP L1B TA2TB (from Antenna Temperature (TA) to the Earth's surface Brightness Temperature (TB)) algorithm and TA forward models are outlined, and validation approaches to calibration stability/quality are described in this paper including future work. Results show that the current radiometer L1B data satisfies its requirements.

  15. Retrieval of Atmospheric Temperature from Airborne Microwave Radiometer Observations

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  16. Wiener filtering of the COBE Differential Microwave Radiometer data

    NASA Technical Reports Server (NTRS)

    Bunn, Emory F.; Fisher, Karl B.; Hoffman, Yehuda; Lahav, Ofer; Silk, Joseph; Zaroubi, Saleem

    1994-01-01

    We derive an optimal linear filter to suppress the noise from the cosmic background explorer satellite (COBE) Differential Microwave Radiometer (DMR) sky maps for a given power spectrum. We then apply the filter to the first-year DMR data, after removing pixels within 20 deg of the Galactic plane from the data. We are able to identify particular hot and cold spots in the filtered maps at a level 2 to 3 times the noise level. We use the formalism of constrained realizations of Gaussian random fields to assess the uncertainty in the filtered sky maps. In addition to improving the signal-to-noise ratio of the map as a whole, these techniques allow us to recover some information about the cosmic microwave background anisotropy in the missing Galactic plane region. From these maps we are able to determine which hot and cold spots in the data are statistically significant, and which may have been produced by noise. In addition, the filtered maps can be used for comparison with other experiments on similar angular scales.

  17. Advanced Microwave Precipitation Radiometer (AMPR) for remote observation of precipitation

    NASA Technical Reports Server (NTRS)

    Galliano, J. A.; Platt, R. H.

    1990-01-01

    The design, development, and tests of the Advanced Microwave Precipitation Radiometer (AMPR) operating in the 10 to 85 GHz range specifically for precipitation retrieval and mesoscale storm system studies from a high altitude aircraft platform (i.e., ER-2) are described. The primary goals of AMPR are the exploitation of the scattering signal of precipitation at frequencies near 10, 19, 37, and 85 GHz together to unambiguously retrieve precipitation and storm structure and intensity information in support of proposed and planned space sensors in geostationary and low earth orbit, as well as storm-related field experiments. The development of AMPR will have an important impact on the interpretation of microwave radiances for rain retrievals over both land and ocean for the following reasons: (1) A scanning instrument, such as AMPR, will allow the unambiguous detection and analysis of features in two dimensional space, allowing an improved interpretation of signals in terms of cloud features, and microphysical and radiative processes; (2) AMPR will offer more accurate comparisons with ground-based radar data by feature matching since the navigation of the ER-2 platform can be expected to drift 3 to 4 km per hour of flight time; and (3) AMPR will allow underflights of the SSM/I satellite instrument with enough spatial coverage at the same frequencies to make meaningful comparisons of the data for precipitation studies.

  18. The NASA Airborne Earth Science Microwave Imaging Radiometer (AESMIR): A New Sensor for Earth Remote Sensing

    NASA Technical Reports Server (NTRS)

    Kim, Edward

    2003-01-01

    The Airborne Earth Science Microwave Imaging Radiometer (AESMIR) is a versatile new airborne imaging radiometer recently developed by NASA. The AESMIR design is unique in that it performs dual-polarized imaging at all standard passive microwave frequency bands (6-89 GHz) using only one sensor headscanner package, providing an efficient solution for Earth remote sensing applications (snow, soil moisture/land parameters, precipitation, ocean winds, sea surface temperature, water vapor, sea ice, etc.). The microwave radiometers themselves will incorporate state-of-the-art receivers, with particular attention given to instrument calibration for the best possible accuracy and sensitivity. The single-package design of AESMIR makes it compatible with high-altitude aircraft platforms such as the NASA ER-2s. The arbitrary 2-axis gimbal can perform conical and cross-track scanning, as well as fixed-beam staring. This compatibility with high-altitude platforms coupled with the flexible scanning configuration, opens up previously unavailable science opportunities for convection/precip/cloud science and co-flying with complementary instruments, as well as providing wider swath coverage for all science applications. By designing AESMIR to be compatible with these high-altitude platforms, we are also compatible with the NASA P-3, the NASA DC-8, C-130s and ground-based deployments. Thus AESMIR can provide low-, mid-, and high- altitude microwave imaging. Parallel filter banks allow AESMIR to simultaneously simulate the exact passbands of multiple satellite radiometers: SSM/I, TMI, AMSR, Windsat, SSMI/S, and the upcoming GPM/GMI and NPOESS/CMIS instruments --a unique capability among aircraft radiometers. An L-band option is also under development, again using the same scanner. With this option, simultaneous imaging from 1.4 to 89 GHz will be feasible. And, all receivers except the sounding channels will be configured for 4-Stokes polarimetric operation using high-speed digital

  19. The NASA Airborne Earth Science Microwave Imaging Radiometer (AESMIR): A New Sensor for Earth Remote Sensing

    NASA Technical Reports Server (NTRS)

    Kim, Edward

    2003-01-01

    The Airborne Earth Science Microwave Imaging Radiometer (AESMIR) is a versatile new airborne imaging radiometer recently developed by NASA. The AESMIR design is unique in that it performs dual-polarized imaging at all standard passive microwave frequency bands (6-89 GHz) using only one sensor headscanner package, providing an efficient solution for Earth remote sensing applications (snow, soil moisture/land parameters, precipitation, ocean winds, sea surface temperature, water vapor, sea ice, etc.). The microwave radiometers themselves will incorporate state-of-the-art receivers, with particular attention given to instrument calibration for the best possible accuracy and sensitivity. The single-package design of AESMIR makes it compatible with high-altitude aircraft platforms such as the NASA ER-2s. The arbitrary 2-axis gimbal can perform conical and cross-track scanning, as well as fixed-beam staring. This compatibility with high-altitude platforms coupled with the flexible scanning configuration, opens up previously unavailable science opportunities for convection/precip/cloud science and co-flying with complementary instruments, as well as providing wider swath coverage for all science applications. By designing AESMIR to be compatible with these high-altitude platforms, we are also compatible with the NASA P-3, the NASA DC-8, C-130s and ground-based deployments. Thus AESMIR can provide low-, mid-, and high- altitude microwave imaging. Parallel filter banks allow AESMIR to simultaneously simulate the exact passbands of multiple satellite radiometers: SSM/I, TMI, AMSR, Windsat, SSMI/S, and the upcoming GPM/GMI and NPOESS/CMIS instruments --a unique capability among aircraft radiometers. An L-band option is also under development, again using the same scanner. With this option, simultaneous imaging from 1.4 to 89 GHz will be feasible. And, all receivers except the sounding channels will be configured for 4-Stokes polarimetric operation using high-speed digital

  20. Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) PARM tape user's guide

    NASA Technical Reports Server (NTRS)

    Han, D.; Gloersen, P.; Kim, S. T.; Fu, C. C.; Cebula, R. P.; Macmillan, D.

    1992-01-01

    The Scanning Multichannel Microwave Radiometer (SMMR) instrument, onboard the Nimbus-7 spacecraft, collected data from Oct. 1978 until Jun. 1986. The data were processed to physical parameter level products. Geophysical parameters retrieved include the following: sea-surface temperatures, sea-surface windspeed, total column water vapor, and sea-ice parameters. These products are stored on PARM-LO, PARM-SS, and PARM-30 tapes. The geophysical parameter retrieval algorithms and the quality of these products are described for the period between Nov. 1978 and Oct 1985. Additionally, data formats and data availability are included.

  1. Microwave radiometer and scatterometer design for the aquarius sea surface Salinity Mission

    NASA Technical Reports Server (NTRS)

    Wilson, William J.; Yueh, Simon H.; Pellerano, Fernando

    2004-01-01

    The measurement of sea surface salinity with L-band microwave radiometers is a very challenging task. Since the L-band brightness temperature variations associated with salinity changes are small, it is necessary to have a very sensitive and stable radiometer. In addition, the corrections for the ocean surface roughness require real time scatterometer measurements. The designs of the Aquarius radiometer and scatterometer are described in this paper.

  2. Calibration of ground-based microwave radiometers - Accuracy assessment and recommendations for network users

    NASA Astrophysics Data System (ADS)

    Pospichal, Bernhard; Küchler, Nils; Löhnert, Ulrich; Crewell, Susanne; Czekala, Harald; Güldner, Jürgen

    2016-04-01

    Ground-based microwave radiometers (MWR) are becoming widely used in atmospheric remote sensing and start to be routinely operated by national weather services and other institutions. However, common standards for calibration of these radiometers and a detailed knowledge about the error characteristics is needed, in order to assimilate the data into models. Intercomparisons of calibrations by different MWRs have rarely been done. Therefore, two calibration experiments in Lindenberg (2014) and Meckenheim (2015) were performed in the frame of TOPROF (Cost action ES1303) in order to assess uncertainties and differences between various instruments. In addition, a series of experiments were taken in Oklahoma in autumn 2014. The focus lay on the performance of the two main instrument types, which are currently used operationally. These are the MP-Profiler series by Radiometrics Corporation as well as the HATPRO series by Radiometer Physics GmbH (RPG). Both instrument types are operating in two frequency bands, one along the 22 GHz water vapour line, the other one at the lower wing of the 60 GHz oxygen absorption complex. The goal was to establish protocols for providing quality controlled (QC) MWR data and their uncertainties. To this end, standardized calibration procedures for MWR were developed and recommendations for radiometer users were compiled. We focus here mainly on data types, integration times and optimal settings for calibration intervals, both for absolute (liquid nitrogen, tipping curve) as well as relative (hot load, noise diode) calibrations. Besides the recommendations for ground-based MWR operators, we will present methods to determine the accuracy of the calibration as well as means for automatic data quality control. In addition, some results from the intercomparison of different radiometers will be discussed.

  3. Quicklook Constituent Abundance and Stretch Parameter Retrieval for the Juno Microwave Radiometer using Neural Networks

    NASA Astrophysics Data System (ADS)

    Bellotti, A.; Steffes, P. G.

    2016-12-01

    The Juno Microwave Radiometer (MWR) has six channels ranging from 1.36-50 cm and the ability to peer deep into the Jovian atmosphere. An Artifical Neural Network algorithm has been developed to rapidly perform inversion for the deep abundance of ammonia, the deep abundance of water vapor, and atmospheric "stretch" (a parameter that reflects the deviation from a wet adiabate in the higher atmosphere). This algorithm is "trained" by using simulated emissions at the six wavelengths computed using the Juno atmospheric microwave radiative transfer (JAMRT) model presented by Oyafuso et al. (This meeting). By exploiting the emission measurements conducted at six wavelengths and at various incident angles, the neural network can provide preliminary results to a useful precison in a computational method hundreds of times faster than conventional methods. This can quickly provide important insights into the variability and structure of the Jovian atmosphere.

  4. Atmospheric moisture measurements - A microwave radiometer-radiosonde comparison

    NASA Technical Reports Server (NTRS)

    England, Martin N.; Schmidlin, F. J.; Johansson, Jan M.

    1993-01-01

    Measurements of the thermal emission of the sky at three frequencies (20.7, 22.2, and 31.4 GHz) with the NASA/Goddard Space Flight Center Crustal Dynamics Project MW Water Vapor Radiometer are reported. These measurements are compared with brightness temperatures inferred from measurements from VAISALA radiosonde packages launched every 3 hr during the experiment period. An error analysis for the radiosonde-inferred brightness temperatures is performed under the assumption of reasonable random uncertainties for the pressure, temperature, and humidity measurements and propagation of these uncertainties through the analysis algorithm. For the assumed uncertainties, the dominant contribution to the total uncertainty comes from the temperature measurement (66-88 percent), whereas the relative humidity measurement contributes only 2-8 percent, except in the vicinity of the water vapor line, where the contribution is 10-20 percent.

  5. Assessing the accuracy of microwave radiometers and radio acoustic sounding systems for wind energy applications

    NASA Astrophysics Data System (ADS)

    Bianco, Laura; Friedrich, Katja; Wilczak, James M.; Hazen, Duane; Wolfe, Daniel; Delgado, Ruben; Oncley, Steven P.; Lundquist, Julie K.

    2017-05-01

    To assess current remote-sensing capabilities for wind energy applications, a remote-sensing system evaluation study, called XPIA (eXperimental Planetary boundary layer Instrument Assessment), was held in the spring of 2015 at NOAA's Boulder Atmospheric Observatory (BAO) facility. Several remote-sensing platforms were evaluated to determine their suitability for the verification and validation processes used to test the accuracy of numerical weather prediction models.The evaluation of these platforms was performed with respect to well-defined reference systems: the BAO's 300 m tower equipped at six levels (50, 100, 150, 200, 250, and 300 m) with 12 sonic anemometers and six temperature (T) and relative humidity (RH) sensors; and approximately 60 radiosonde launches.In this study we first employ these reference measurements to validate temperature profiles retrieved by two co-located microwave radiometers (MWRs) as well as virtual temperature (Tv) measured by co-located wind profiling radars equipped with radio acoustic sounding systems (RASSs). Results indicate a mean absolute error (MAE) in the temperature retrieved by the microwave radiometers below 1.5 K in the lowest 5 km of the atmosphere and a mean absolute error in the virtual temperature measured by the radio acoustic sounding systems below 0.8 K in the layer of the atmosphere covered by these measurements (up to approximately 1.6-2 km). We also investigated the benefit of the vertical velocity correction applied to the speed of sound before computing the virtual temperature by the radio acoustic sounding systems. We find that using this correction frequently increases the RASS error, and that it should not be routinely applied to all data.Water vapor density (WVD) profiles measured by the MWRs were also compared with similar measurements from the soundings, showing the capability of MWRs to follow the vertical profile measured by the sounding and finding a mean absolute error below 0.5 g m-3 in the lowest

  6. Assessing the accuracy of microwave radiometers and radio acoustic sounding systems for wind energy applications

    DOE PAGES

    Bianco, Laura; Friedrich, Katja; Wilczak, James M.; ...

    2017-05-09

    To assess current remote-sensing capabilities for wind energy applications, a remote-sensing system evaluation study, called XPIA (eXperimental Planetary boundary layer Instrument Assessment), was held in the spring of 2015 at NOAA's Boulder Atmospheric Observatory (BAO) facility. Several remote-sensing platforms were evaluated to determine their suitability for the verification and validation processes used to test the accuracy of numerical weather prediction models.The evaluation of these platforms was performed with respect to well-defined reference systems: the BAO's 300 m tower equipped at six levels (50, 100, 150, 200, 250, and 300 m) with 12 sonic anemometers and six temperature (T) and relativemore » humidity (RH) sensors; and approximately 60 radiosonde launches.In this study we first employ these reference measurements to validate temperature profiles retrieved by two co-located microwave radiometers (MWRs) as well as virtual temperature (Tv) measured by co-located wind profiling radars equipped with radio acoustic sounding systems (RASSs). Results indicate a mean absolute error (MAE) in the temperature retrieved by the microwave radiometers below 1.5 K in the lowest 5?km of the atmosphere and a mean absolute error in the virtual temperature measured by the radio acoustic sounding systems below 0.8 K in the layer of the atmosphere covered by these measurements (up to approximately 1.6-2 km). We also investigated the benefit of the vertical velocity correction applied to the speed of sound before computing the virtual temperature by the radio acoustic sounding systems. We find that using this correction frequently increases the RASS error, and that it should not be routinely applied to all data.Water vapor density (WVD) profiles measured by the MWRs were also compared with similar measurements from the soundings, showing the capability of MWRs to follow the vertical profile measured by the sounding and finding a mean absolute error below 0.5 g m-3 in the

  7. Network operability of ground-based microwave radiometers: Calibration and standardization efforts

    NASA Astrophysics Data System (ADS)

    Pospichal, Bernhard; Löhnert, Ulrich; Küchler, Nils; Czekala, Harald

    2017-04-01

    Ground-based microwave radiometers (MWR) are already widely used by national weather services and research institutions all around the world. Most of the instruments operate continuously and are beginning to be implemented into data assimilation for atmospheric models. Especially their potential for continuously observing boundary-layer temperature profiles as well as integrated water vapor and cloud liquid water path makes them valuable for improving short-term weather forecasts. However until now, most MWR have been operated as stand-alone instruments. In order to benefit from a network of these instruments, standardization of calibration, operation and data format is necessary. In the frame of TOPROF (COST Action ES1303) several efforts have been undertaken, such as uncertainty and bias assessment, or calibration intercomparison campaigns. The goal was to establish protocols for providing quality controlled (QC) MWR data and their uncertainties. To this end, standardized calibration procedures for MWR have been developed and recommendations for radiometer users compiled. Based on the results of the TOPROF campaigns, a new, high-accuracy liquid-nitrogen calibration load has been introduced for MWR manufactured by Radiometer Physics GmbH (RPG). The new load improves the accuracy of the measurements considerably and will lead to even more reliable atmospheric observations. Next to the recommendations for set-up, calibration and operation of ground-based MWR within a future network, we will present homogenized methods to determine the accuracy of a running calibration as well as means for automatic data quality control. This sets the stage for the planned microwave calibration center at JOYCE (Jülich Observatory for Cloud Evolution), which will be shortly introduced.

  8. An RFI Detection Algorithm for Microwave Radiometers Using Sparse Component Analysis

    NASA Technical Reports Server (NTRS)

    Mohammed-Tano, Priscilla N.; Korde-Patel, Asmita; Gholian, Armen; Piepmeier, Jeffrey R.; Schoenwald, Adam; Bradley, Damon

    2017-01-01

    Radio Frequency Interference (RFI) is a threat to passive microwave measurements and if undetected, can corrupt science retrievals. The sparse component analysis (SCA) for blind source separation has been investigated to detect RFI in microwave radiometer data. Various techniques using SCA have been simulated to determine detection performance with continuous wave (CW) RFI.

  9. Ultra Stable Microwave Radiometers for Future Sea Surface Salinity Missions

    NASA Technical Reports Server (NTRS)

    Wilson, William J.; Tanner, Alan B.; Pellerano, Fernando A.; Horgan, Kevin A.

    2005-01-01

    The NASA Earth Science System Pathfinder (ESSP) mission Aquarius will measure global sea surface salinity with 100-km spatial resolution every 8 days with an average monthly salinity accuracy of 0.2 psu (parts per thousand). This requires an L-band low-noise radiometer with the long-term calibration stability of less than 0.1 K over 8 days. This three-year research program on ultra stable radiometers has addressed the radiometer requirements and configuration necessary to achieve this objective for Aquarius and future ocean salinity missions. The system configuration and component performance have been evaluated with radiometer testbeds at both JPL and GSFC. The research has addressed several areas including component characterization as a function of temperature, a procedure for the measurement and correction for radiometer system non-linearity, noise diode calibration versus temperature, low noise amplifier performance over voltage, and temperature control requirements to achieve the required stability. A breadboard radiometer, utilizing microstrip-based technologies, has been built to demonstrate this long-term stability. This report also presents the results of the radiometer test program, a detailed radiometer noise model, and details of the operational switching sequence optimization that can be used to achieve the low noise and stability requirements. Many of the results of this research have been incorporated into the Aquarius radiometer design and will allow this instrument to achieve its goals.

  10. Low Power Silicon Germanium Electronics for Microwave Radiometers

    NASA Technical Reports Server (NTRS)

    Doiron, Terence A.; Krebs, Carolyn (Technical Monitor)

    2001-01-01

    Space-based radiometric observations of key hydrological parameters (e.g., soil moisture) at the spatial and temporal scales required in the post-2002 era face significant technological challenges. These measurements are based on relatively low frequency thermal microwave emission (at 1.4 GHz for soil moisture and salinity, 10 GHz and up for precipitation, and 19 and 37 GHz for snow). The long wavelengths at these frequencies coupled with the high spatial and radiometric resolutions required by the various global hydrology communities necessitate the use of very large apertures (e.g., greater than 20 m at 1.4 GHz) and highly integrated stable RF electronics on orbit. Radio-interferometric techniques such as Synthetic Thinned Array Radiometry (STAR), using silicon germanium (SiGe) low power radio frequency integrated circuits (RFIC), is one of the most promising technologies to enable very large non-rotating apertures in space. STAR instruments are composed of arrays of small antenna/receiving elements that are arranged so that the collecting area is smaller than an equivalent real aperture system, allowing very high packing densities for launch. A 20 meter aperture at L-band, for example, will require greater than 1000 of these receiving elements. SiGe RFIC's reduce power consumption enough to make an array like this possible in the power-limited environment of space flight. An overview of the state-of-the-art will be given, and current work in the area of SiGe radiometer development for soil moisture remote sensing will be discussed.

  11. Mixing layer height retrievals by multichannel microwave radiometer observations

    NASA Astrophysics Data System (ADS)

    Cimini, D.; De Angelis, F.; Dupont, J.-C.; Pal, S.; Haeffelin, M.

    2013-06-01

    The mixing layer height (MLH) is a key parameter for boundary layer studies, including meteorology, air quality, and climate. MLH estimates are inferred from in situ radiosonde measurements or remote sensing observations from instruments like lidar, wind profiling radar, or sodar. Methods used to estimate MLH from radiosonde profiles are also used with atmospheric temperature and humidity profiles retrieved by microwave radiometers (MWR). This paper proposes an alternative approach to estimate MLH from MWR data, based on direct observations (brightness temperatures, Tb) instead of retrieved profiles. To our knowledge, MLH estimates directly from Tb observations has never been attempted before. The method consists of a multivariate linear regression trained with an a priori set of collocated MWR Tb observations (multi-frequency and multi-angle) and MLH estimates from a state-of-the-art lidar system. Results show that the method is able to follow both the diurnal cycle and the day-to-day variability as suggested by the lidar measurements, and also it can detect low MLH values that are below the full overlap limit (~ 200 m) of the lidar system used. Statistics of the comparison between MWR- and reference lidar-based MLH retrievals show mean difference within 10 m, RMS within 340 m, and correlation coefficient higher than 0.77. Monthly mean analysis for day-time MLH from MWR, lidar, and radiosonde shows consistent seasonal variability, peaking at ~ 1200-1400 m in June and decreasing down to ~ 600 m in October. Conversely, night-time monthly mean MLH from all methods are within 300-500 m without any significant seasonal variability. The proposed method provides results that are more consistent with radiosonde estimates than MLH estimates from MWR retrieved profiles. MLH monthly mean values agree well within 1 std with bulk Richardson number method applied at radiosonde profiles at 11:00 and 23:00 UTC. The method described herewith operates continuously and it is

  12. Mixing layer height retrievals by multichannel microwave radiometer observations

    NASA Astrophysics Data System (ADS)

    Cimini, D.; De Angelis, F.; Dupont, J.-C.; Pal, S.; Haeffelin, M.

    2013-11-01

    The mixing layer height (MLH) is a key parameter for boundary layer studies, including meteorology, air quality, and climate. MLH estimates are inferred from in situ radiosonde measurements or remote sensing observations from instruments like lidar, wind profiling radar, or sodar. Methods used to estimate MLH from radiosonde profiles are also used with atmospheric temperature and humidity profiles retrieved by microwave radiometers (MWR). This paper proposes an alternative approach to estimate MLH from MWR data, based on direct observations (brightness temperatures, Tb) instead of retrieved profiles. To our knowledge, MLH estimates directly from Tb observations have never been attempted before. The method consists of a multivariate linear regression trained with an a priori set of collocated MWR Tb observations (multifrequency and multi-angle) and MLH estimates from a state-of-the-art lidar system. The proposed method was applied to a 7-month data set collected at a typical midlatitude site. Results show that the method is able to follow both the diurnal cycle and the day-to-day variability as suggested by the lidar measurements, and also it can detect low MLH values that are below the full overlap limit (~200 m) of the lidar system used. Statistics of the comparison between MWR- and reference lidar-based MLH retrievals show mean difference within 10 m, root mean square within 340 m, and correlation coefficient higher than 0.77. Monthly mean analysis for daytime MLH from MWR, lidar, and radiosonde shows consistent seasonal variability, peaking at ~1200-1400 m in June and decreasing down to ~600 m in October. Conversely, nighttime monthly mean MLH from all methods are within 300-500 m without any significant seasonal variability. The proposed method provides results that are more consistent with radiosonde estimates than MLH estimates from MWR-retrieved profiles. MLH monthly mean values agree well within 1 standard deviation with the bulk Richardson number method

  13. Baseline Observations of Hemispheric Sea Ice with the Nimbus 7 Scanning Multichannel Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Gloersen, Per

    1998-01-01

    The Scanning Multichannel Microwave Radiometer (SMMR) on board the NASA Nimbus 7 satellite was designed to obtain data for sea surface temperatures (SSTs), near-surface wind speeds, sea ice coverage and type, rainfall rates over the oceans, cloud water content, snow water equivalent, and soil moisture. In this paper, I shall emphasize the sea ice observations and mention briefly some important SST observations. A prime factor contributing to the importance of SMMR sea ice observations lies in their successful integration into a long-term time series, presently being extended by observations from the series of Special Sensor Microwave/Imager (SSMI) on board the DOD/DMSP F8, Fl1, and F12 satellites. This currently constitutes a 19-year data set. Almost half of this was provided by the SMMR. Unfortunately, the 4-year data set produced earlier by the single-channel Electrically Scanned Microwave Radiometer (ESMR) was not successfully integrated into the SMMR/SSMI data set. This resulted primarily from the lack of an overlap period to provide intersensor adjustment, but also because of the large difference between the algorithms to produce ice concentrations and large temporal gaps in the ESMR data. The lack of overlap between the SeaSat and Nimbus 7 SMMR data sets was an important consideration for also excluding the SeatSat one, but the spatial gaps especially in the Southern Hemisphere daily SeaSat observations was another. The sea ice observations will continue into the future by means of the Advanced Microwave Scanning Radiometer (AMSR) on board the ADEOS II and EOS satellites due to be launched in mid- and late-2000, respectively. Analysis of the sea ice data has been carried out by a number of different techniques. Long-term trends have been examined by means of ordinary least squares and band-limited regression. Oscillations in the data have been examined by band-limited Fourier analysis. Here, I shall present results from a novel combination of Principal

  14. High-resolution imaging of rain systems with the advanced microwave precipitation radiometer

    NASA Technical Reports Server (NTRS)

    Spencer, Roy W.; Hood, Robbie E.; Lafontaine, Frank J.; Smith, Eric A.; Platt, Robert; Galliano, Joe; Griffin, Vanessa L.; Lobl, Elena

    1994-01-01

    An advanced Microwave Precipitation Radiometer (AMPR) has been developed and flown in the NASA ER-2-high-altitude aircraft for imaging various atmospheric and surface processes, primarily the internal structure of rain clouds. The AMPR is a scanning four-frequency total power microwave radiometer that is externally calibrated with high-emissivity warm and cold loads. Separate antenna systems allow the sampling of the 10.7- and 19.35-GHz channels at the same spatial resolution, while the 37.1- and 85.5-GHz channels utilize the same multifrequency feedhorn as the 19.35-GHz channel. Spatial resolutions from an aircraft altitude of 20-km range from 0.6 km at 85.5 GHz to 2.8 km at 19.35 and 10.7 GHz. All channels are sampled every 0.6 km in both along-track and cross-track directions, leading to a contiguous sampling pattern of the 85.5-GHz 3-dB beamwidth footprints, 2.3X oversampling of the 37.1-GHz data, and 4.4X oversampling of the 19.35- and 10.7-GHz data. Radiometer temperature sensitivities range from 0.2 to 0.5 C. Details of the system are described, including two different calibration systems and their effect on the data collected. Examples of oceanic rain systems are presented from Florida and the tropical west Pacific that illustrate the wide variety of cloud water, rainwater, and precipitation-size ice combinations that are observable from aircraft altitudes.

  15. On the Long-Term Stability of Microwave Radiometers Using Noise Diodes for Calibration

    NASA Technical Reports Server (NTRS)

    Brown, Shannon T.; Desai, Shailen; Lu, Wenwen; Tanner, Alan B.

    2007-01-01

    Results are presented from the long-term monitoring and calibration of the National Aeronautics and Space Administration Jason Microwave Radiometer (JMR) on the Jason-1 ocean altimetry satellite and the ground-based Advanced Water Vapor Radiometers (AWVRs) developed for the Cassini Gravity Wave Experiment. Both radiometers retrieve the wet tropospheric path delay (PD) of the atmosphere and use internal noise diodes (NDs) for gain calibration. The JMR is the first radiometer to be flown in space that uses NDs for calibration. External calibration techniques are used to derive a time series of ND brightness for both instruments that is greater than four years. For the JMR, an optimal estimator is used to find the set of calibration coefficients that minimize the root-mean-square difference between the JMR brightness temperatures and the on-Earth hot and cold references. For the AWVR, continuous tip curves are used to derive the ND brightness. For the JMR and AWVR, both of which contain three redundant NDs per channel, it was observed that some NDs were very stable, whereas others experienced jumps and drifts in their effective brightness. Over the four-year time period, the ND stability ranged from 0.2% to 3% among the diodes for both instruments. The presented recalibration methodology demonstrates that long-term calibration stability can be achieved with frequent recalibration of the diodes using external calibration techniques. The JMR PD drift compared to ground truth over the four years since the launch was reduced from 3.9 to - 0.01 mm/year with the recalibrated ND time series. The JMR brightness temperature calibration stability is estimated to be 0.25 K over ten days.

  16. Microwave radiometer measurement of tidally induced salinity changes off the Georgia coast

    SciTech Connect

    Kendall, B.M.; Blanton, J.O.

    1981-07-01

    A quasi-synoptic survey of tidally induced salinity changes off the Georgia coast was performed by using a L band microwave radiometer onboard a NASA aircraft. Salinity maps were obtained for ebb and flood conditions in order to define the salinity distributions near rivers and sounds and major changes that occur from ebb flow to flood flow. The Savannah River plume dominated the salinity regime and extended out from the Savannah River mouth about 12 km during ebb tidal conditions. The plume merged into a band of low salinity water extending along the Georgia-South Carolina coast which was produced by the many river sources of freshwater entering the coastal waters. The changes in salinity observed offshore of the river plume area were consistent with estimates of the changes that would occur over a typical tidal excursion perpendicular to the observed gradient. 7 references, 5 figures.

  17. Advanced systems requirements for ocean observations via microwave radiometers

    NASA Technical Reports Server (NTRS)

    Blume, H.-J. C.; Swift, C. T.; Kendall, B. M.

    1978-01-01

    A future microwave spectroradiometer operating in several frequency bands will have the capability to step or sweep frequencies on an adaptable or programmable basis. The on-board adaptable frequency shifting can make the systems immune from radio interference. Programmable frequency sweeping with on-board data inversion by high speed computers would provide for instantaneous synoptic measurements or sea surface temperature and salinity, water surface and volume pollution, ice thickness, ocean surface winds, snow depth, and soil moisture. Large structure satellites will allow an order of magnitude improvement in the present radiometric measurement spacial resolution.

  18. Advanced systems requirements for ocean observations via microwave radiometers

    NASA Technical Reports Server (NTRS)

    Blume, H.-J. C.; Swift, C. T.; Kendall, B. M.

    1978-01-01

    A future microwave spectroradiometer operating in several frequency bands will have the capability to step or sweep frequencies on an adaptable or programmable basis. The on-board adaptable frequency shifting can make the systems immune from radio interference. Programmable frequency sweeping with on-board data inversion by high speed computers would provide for instantaneous synoptic measurements or sea surface temperature and salinity, water surface and volume pollution, ice thickness, ocean surface winds, snow depth, and soil moisture. Large structure satellites will allow an order of magnitude improvement in the present radiometric measurement spacial resolution.

  19. A New Principle for Construction of Microwave Multireceiver Radiometers Using a Modified Method of Zero Measurement

    NASA Astrophysics Data System (ADS)

    Filatov, A. V.

    2016-11-01

    We consider a microwave multireceiver radiometer based on in-parallel operated receiving channels using the principle of zero balance and measuring the antenna signal by all receivers in the same spectral range with time division. This yields a higher fluctuation sensitivity than in the case of an ideal full-power compensation radiometer while achieving a high stability of measurements by a modified method of zero measurement.

  20. Soil Moisture ActivePassive (SMAP) L-Band Microwave Radiometer Post-Launch Calibration

    NASA Technical Reports Server (NTRS)

    Peng, Jinzheng; Piepmeier, Jeffrey R.; Misra, Sidharth; Dinnat, Emmanuel P.; Hudson, Derek; Le Vine, David M.; De Amici, Giovanni; Mohammed, Priscilla N.; Yueh, Simon H.; Meissner, Thomas

    2016-01-01

    The SMAP microwave radiometer is a fully-polarimetric L-band radiometer flown on the SMAP satellite in a 6 AM/ 6 PM sun-synchronous orbit at 685 km altitude. Since April, 2015, the radiometer is under calibration and validation to assess the quality of the radiometer L1B data product. Calibration methods including the SMAP L1B TA2TB (from Antenna Temperature (TA) to the Earth’s surface Brightness Temperature (TB)) algorithm and TA forward models are outlined, and validation approaches to calibration stability/quality are described in this paper including future work. Results show that the current radiometer L1B data satisfies its requirements.

  1. Microwave remote sensing of soil water content

    NASA Technical Reports Server (NTRS)

    Cihlar, J.; Ulaby, F. T.

    1975-01-01

    Microwave remote sensing of soils to determine water content was considered. A layered water balance model was developed for determining soil water content in the upper zone (top 30 cm), while soil moisture at greater depths and near the surface during the diurnal cycle was studied using experimental measurements. Soil temperature was investigated by means of a simulation model. Based on both models, moisture and temperature profiles of a hypothetical soil were generated and used to compute microwave soil parameters for a clear summer day. The results suggest that, (1) soil moisture in the upper zone can be predicted on a daily basis for 1 cm depth increments, (2) soil temperature presents no problem if surface temperature can be measured with infrared radiometers, and (3) the microwave response of a bare soil is determined primarily by the moisture at and near the surface. An algorithm is proposed for monitoring large areas which combines the water balance and microwave methods.

  2. TOPEX/Poseidon Microwave Radiometer (TMR): 1. Instrument Description and Antenna Temperature Calibration

    NASA Technical Reports Server (NTRS)

    Ruf, C. S.; Keihm, S. J.; Janssen, M. A.

    1993-01-01

    The TOPEX/Poseidon Microwave Radiometer (TMR) is a 3-frequency radiometer flown on the TOPEX/Poseidon (T/P) satellite in low Earth orbit. It operates at 18, 21 and 37 GHz in a nadir only viewing direction which is co-aligned with the T/P radar altimeters. TMR monitors and corrects for the electrical path delay of the altimeter radar signal due to water vapor and non-precipitating liquid water in the atmosphere. This paper describes the TMR instrument and the radiometric instrument calibration required to derive antenna temperature (T_A) from the raw digital data. T_A precision of 0.4 K is predicted on orbit in all expected thermal environments. T_A accuracy of 0.5-0.6 K is expected following a post-launch field calibration campaign. When uncertainties related to antenna sidelobe corrections are included, this T_A accuracy yields a brightness temperature accuracy of 0.7- 0.8 K...

  3. TOPEX/Poseidon Microwave Radiometer (TMR): 1. Instrument Description and Antenna Temperature Calibration

    NASA Technical Reports Server (NTRS)

    Ruf, C. S.; Keihm, S. J.; Janssen, M. A.

    1993-01-01

    The TOPEX/Poseidon Microwave Radiometer (TMR) is a 3-frequency radiometer flown on the TOPEX/Poseidon (T/P) satellite in low Earth orbit. It operates at 18, 21 and 37 GHz in a nadir only viewing direction which is co-aligned with the T/P radar altimeters. TMR monitors and corrects for the electrical path delay of the altimeter radar signal due to water vapor and non-precipitating liquid water in the atmosphere. This paper describes the TMR instrument and the radiometric instrument calibration required to derive antenna temperature (T_A) from the raw digital data. T_A precision of 0.4 K is predicted on orbit in all expected thermal environments. T_A accuracy of 0.5-0.6 K is expected following a post-launch field calibration campaign. When uncertainties related to antenna sidelobe corrections are included, this T_A accuracy yields a brightness temperature accuracy of 0.7- 0.8 K...

  4. Calibration and Performance Of The Juno Microwave Radiometer In Jupiter Orbit

    NASA Astrophysics Data System (ADS)

    Brown, Shannon; Janssen, Mike; Misra, Sid

    2017-04-01

    The NASA Juno mission was launched from Kennedy Space Center on August 5th, 2011. Juno is a New Frontiers mission to study Jupiter and carries as one of its payloads a six-frequency microwave radiometer to retrieve the water vapor abundance in the Jovian atmosphere, down to at least 100 bars. The Juno Microwave Radiometer (MWR) operates from 600 MHz to 22 GHz and was designed and built at the Jet Propulsion Laboratory. The MWR radiometer system consists of a MMIC-based receiver for each channel that includes a PIN-diode Dicke switch and three noise diodes distributed along the front end for receiver calibration. The receivers and electronics are housed inside the Juno payload vault, which provides radiation shielding for the Juno payloads. The antenna system consists of patch-array antennas at 600 MHz and 1.2 GHz, slotted waveguide antennas at 2.5, 5.5 and 10 GHz and a feed horn at 22 GHz, providing 20-degree beams at the lowest two frequencies and 12-degree beams at the others. Since launch, MWR has operated nearly continually over the five year cruise. During this time, the Juno spacecraft is spinning on the sky providing the MWR with an excellent calibration source. Furthermore, the spacecraft sun angle and distance have varied, offering a wide range of instrument thermal states to further constrain the calibration. An approach was developed to optimally use the pre-launch and post-launch data to find a calibration solution which minimizes the errors with respect to the pre-launch calibration targets, the post-launch cold sky data and the component level loss/reflection measurements. The extended cruise data allow traceability from the pre-launch measurements to the science observations. In addition, a special data set was taken at apojove during the capture orbits to validate the antenna patterns in-flight using Jupiter as a source. An assessment of the radiometer calibration performance during the first science orbits will be presented. Both the absolute and

  5. Calibration and Performance of the Juno Microwave Radiometer during the First Science Orbits

    NASA Astrophysics Data System (ADS)

    Brown, S. T.; Misra, S.; Janssen, M. A.; Williamson, R.

    2016-12-01

    The NASA Juno mission was launched from Kennedy Space Center on August 5, 2011 and reached Jupiter orbit on July 4, 2016. Juno is a New Frontiers mission to study Jupiter and carries as one of its payloads a six-frequency microwave radiometer to retrieve the water vapor abundance in the Jovian atmosphere, down to at least 100 bars. The Juno Microwave Radiometer (MWR) operates from 600 MHz to 22 GHz and was designed and built at the Jet Propulsion Laboratory. The MWR radiometer system consists of a MMIC-based receiver for each channel that includes a PIN-diode Dicke switch and three noise diodes distributed along the front end for receiver calibration. The receivers and electronics are housed inside the Juno payload vault, which provides radiation shielding for the Juno payloads. The antenna system consists of patch-array antennas at 600 MHz and 1.2 GHz, slotted waveguide antennas at 2.5, 5.5 and 10 GHz and a feed horn at 22 GHz, providing 20-degree beams at the lowest two frequencies and 12-degree beams at the others. Since launch, MWR has operated nearly continuously over the five year cruise. During this time, the Juno spacecraft is spinning on the sky providing the MWR with an excellent calibration source. Furthermore, the spacecraft sun angle and distance have varied, offering a wide range of instrument thermal states to further constrain the calibration. An approach was developed to optimally use the pre-launch and post-launch data to find a calibration solution which minimizes the errors with respect to the pre-launch calibration targets, the post-launch sky data and the pre-launch RF component level characterization measurements. The extended cruise data allow traceability from the pre-launch measurements to the science observations. In addition, a special data set was taken at apojove during the capture orbits to validate the antenna patterns in-flight using Jupiter as a source. An assessment of the radiometer calibration performance during the first

  6. Short term prediction of dynamic hydra precipitation activity using a microwave radiometer over Eastern Himalaya, India

    NASA Astrophysics Data System (ADS)

    Singh, S.

    2015-12-01

    First ever study of the feasibility of ground based radiometric study to predict a very short term based rain precipitation study has been conducted in eastern Himalaya, Darjeeling (27.01°N, 88.15°E, 2200 masl). Short term prediction or nowcasting relates to forecasting convective precipitation for time periods less than a few hours to avoid its effect on agriculture, aviation and lifestyle. Theoretical models involving radiometric predictions are not well understood and lack in temporal and spatial resolution. In this study specific utilization of a microwave Radiometer (Radiometrics Corporation, USA) for online monitoring of precipitable rainfall activity has been observed repeatability of data has been established. Previous few studies have shown the increase of water vapour and corresponding Brightness Temperature, but in mountain climatic conditions over Darjeeling, due to presence of fog 90 % of the year, water vapour monitoring related predictions can lead to false alarms. The measurement of blackbody emission noise in the bands of 23.8 GHz and 31.4 GHz, using a quadratic regression retrieval algorithm is converted to atmospheric parameters like integrated water vapour and liquid water content. It has been found in our study that the liquid water shows significant activity prior to precipitation events even for mild and stratiform rainfall. The alarm can be generated well 20 mins before the commencement of actual rain events even in the upper atmosphere of 6 Kms, measured by a rain radar also operating in 24 Ghz microwave band. Although few rain events were found and reported which do not respond in the microwave liquid water channel. Efforts to identify such rain events and their possible explanation is going on and shall be reported in near future. Such studies are important to predict flash flooding in the Himalayas. Darjeeling owing to its geographical conditions experiences mild to very heavy rain. Such studies help improve aspects of Himalayas as

  7. Microwave Radiometers from 0.6 to 22 GHz for Juno, a Polar Orbiter around Jupiter

    NASA Technical Reports Server (NTRS)

    P. Pingree; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.; Smith, S.

    2008-01-01

    A compact radiometer instrument is under development at JPL for Juno, the next NASA New Frontiers mission, scheduled to launch in 2011. This instrument is called the MWR (MicroWave Radiometer), and its purpose is to measure the thermal emission from Jupiter's atmosphere at selected frequencies from 0.6 to 22 GHz. The objective is to measure the distributions and abundances of water and ammonia in Jupiter's atmosphere, with the goal of understanding the previously unobserved dynamics of the subcloud atmosphere, and to discriminate among models for planetary formation in our solar system. The MWR instrument is currently being developed to address these science questions for the Juno mission. As part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The entire MWR instrument consists of six individual radiometer channels with approximately 4% bandwidth at 0.6, 1.25,2.6,5.2, 10,22 GHz operating in direct detection mode. Each radiometer channel has up to 80 dB of gain with a noise figure of several dB. The highest frequency channel uses a corrugated feedhorn and waveguide transmission lines, whereas all other channels use highly phase stable coaxial cables and either patch array or waveguide slot array antennas. Slot waveguide array antennas were chosen for the low loss at the next three highest frequencies and patch array antennas were implemented due to the mass constraint at the two lowest frequencies. The six radiometer channels receive their voltage supplies and control lines from an electronics unit that also provides the instrument communication interface to the Juno spacecraft. For calibration purposes each receiver has integrated noise diodes, a Dicke switch, and temperature sensors near each component that contributes to the noise figure. In addition, multiple sensors will be placed along the RF transmission lines and the antennas in order to measure temperature gradients. All antennas and RF

  8. Microwave Radiometers from 0.6 to 22 GHz for Juno, a Polar Orbiter around Jupiter

    NASA Technical Reports Server (NTRS)

    P. Pingree; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.; Smith, S.

    2008-01-01

    A compact radiometer instrument is under development at JPL for Juno, the next NASA New Frontiers mission, scheduled to launch in 2011. This instrument is called the MWR (MicroWave Radiometer), and its purpose is to measure the thermal emission from Jupiter's atmosphere at selected frequencies from 0.6 to 22 GHz. The objective is to measure the distributions and abundances of water and ammonia in Jupiter's atmosphere, with the goal of understanding the previously unobserved dynamics of the subcloud atmosphere, and to discriminate among models for planetary formation in our solar system. The MWR instrument is currently being developed to address these science questions for the Juno mission. As part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The entire MWR instrument consists of six individual radiometer channels with approximately 4% bandwidth at 0.6, 1.25,2.6,5.2, 10,22 GHz operating in direct detection mode. Each radiometer channel has up to 80 dB of gain with a noise figure of several dB. The highest frequency channel uses a corrugated feedhorn and waveguide transmission lines, whereas all other channels use highly phase stable coaxial cables and either patch array or waveguide slot array antennas. Slot waveguide array antennas were chosen for the low loss at the next three highest frequencies and patch array antennas were implemented due to the mass constraint at the two lowest frequencies. The six radiometer channels receive their voltage supplies and control lines from an electronics unit that also provides the instrument communication interface to the Juno spacecraft. For calibration purposes each receiver has integrated noise diodes, a Dicke switch, and temperature sensors near each component that contributes to the noise figure. In addition, multiple sensors will be placed along the RF transmission lines and the antennas in order to measure temperature gradients. All antennas and RF

  9. Interpretation of the cosmic microwave background radiation anisotropy detected by the COBE Differential Microwave Radiometer

    NASA Technical Reports Server (NTRS)

    Wright, E. L.; Meyer, S. S.; Bennett, C. L.; Boggess, N. W.; Cheng, E. S.; Hauser, M. G.; Kogut, A.; Lineweaver, C.; Mather, J. C.; Smoot, G. F.

    1992-01-01

    The large-scale cosmic background anisotropy detected by the COBE Differential Microwave Radiometer (DMR) instrument is compared to the sensitive previous measurements on various angular scales, and to the predictions of a wide variety of models of structure formation driven by gravitational instability. The observed anisotropy is consistent with all previously measured upper limits and with a number of dynamical models of structure formation. For example, the data agree with an unbiased cold dark matter (CDM) model with H0 = 50 km/s Mpc and Delta-M/M = 1 in a 16 Mpc radius sphere. Other models, such as CDM plus massive neutrinos (hot dark matter (HDM)), or CDM with a nonzero cosmological constant are also consistent with the COBE detection and can provide the extra power seen on 5-10,000 km/s scales.

  10. Retrievals on Tropical small scale humidity variability from multi-channel microwave radiometer

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhao; Zuidema, Paquita; Turner, David

    2016-04-01

    Small-scale atmospheric humidity structure is important to many atmospheric process studies. In the Tropics especially, convection is sensitive to small variations in humidity. High temporal-resolution humidity profiles and spatially-resolved humidity fields are valuable for understanding the relationship of convection to tropical humidity, such as at convectively-induced cold pools and as part of the shallow-to-deep cloud transition. Radiosondes can provide high resolution vertical profiles of temperature and humidity, but are relatively infrequent. Microwave radiometers (MWR) are able to profile and scan autonomously and output measurements frequently (~1 Hz). To date, few assessments of microwave humidity profiling in the Tropics have been undertaken. Löhnert et al. (2009) provide one evaluation for Darwin, Australia. We build on this using four months of data from the equatorial Indian Ocean, at Gan Island, collected from University of Miami's (UM) multi-channel radiometer during the Dynamics of Madden-Julian Oscillation (DYNAMO) field campaign. Liquid Water Path (LWP) and Water Vapor Path (WVP) are physically retrieved using the MWR RETrieval (MWRRET) algorithm (Turner et al., 2007b), and humidity profiles in the tropics are retrieved using the Integrated Profiling Technique (Löhnert et al., 2004). Tropical temperature variability is weak and a climatological temperature profile is assumed, with humidity information drawn from five channels between 22 to 30 GHz. Scanning measurements were coordinated with the scanning pattern of NCAR's S-Pol-Ka radar. An analysis of the humidity information content gathered from both the profiling and scanning measurements will be presented.

  11. Active microwave water equivalence

    NASA Technical Reports Server (NTRS)

    Boyne, H. S.; Ellerbruch, D. A.

    1980-01-01

    Measurements of water equivalence using an active FM-CW microwave system were conducted over the past three years at various sites in Colorado, Wyoming, and California. The measurement method is described. Measurements of water equivalence and stratigraphy are compared with ground truth. A comparison of microwave, federal sampler, and snow pillow measurements at three sites in Colorado is described.

  12. Spatial variability of summer Florida precipitation and its impact on microwave radiometer rainfall-measurement systems

    NASA Technical Reports Server (NTRS)

    Turner, B. J.; Austin, G. L.

    1993-01-01

    Three-dimensional radar data for three summer Florida storms are used as input to a microwave radiative transfer model. The model simulates microwave brightness observations by a 19-GHz, nadir-pointing, satellite-borne microwave radiometer. The statistical distribution of rainfall rates for the storms studied, and therefore the optimal conversion between microwave brightness temperatures and rainfall rates, was found to be highly sensitive to the spatial resolution at which observations were made. The optimum relation between the two quantities was less sensitive to the details of the vertical profile of precipitation. Rainfall retrievals were made for a range of microwave sensor footprint sizes. From these simulations, spatial sampling-error estimates were made for microwave radiometers over a range of field-of-view sizes. The necessity of matching the spatial resolution of ground truth to radiometer footprint size is emphasized. A strategy for the combined use of raingages, ground-based radar, microwave, and visible-infrared (VIS-IR) satellite sensors is discussed.

  13. Air temperature profile and air/sea temperature difference measurements by infrared and microwave scanning radiometers

    NASA Astrophysics Data System (ADS)

    Cimini, D.; Shaw, J. A.; Westwater, E. R.; Han, Y.; Irisov, V.; Leuski, V.; Churnside, J. H.

    2003-06-01

    A system of two scanning radiometers has been developed by the National Oceanic and Atmospheric Administration/Environmental Technology Laboratory and deployed on the NOAA R/V Ronald H. Brown during the Nauru99 cruise in the tropical western Pacific in June and July 1999. The system is composed of a high-quality temperature sensor and two independent, vertically scanning radiometers, measuring atmospheric and oceanic emission in the microwave (MW), and infrared (IR) regions. Both radiometers measure emission from a uniformly mixed atmospheric gas: oxygen for MW (60 GHz) and carbon dioxide for IR (14.2 μm). The high atmospheric absorption at these frequencies allows one calibration point from the horizontal atmospheric view using the in situ temperature sensor measurements as a reference. The signal at all other scan angles is scaled relative to that at the horizontal, resulting in a differential technique that is independent of calibration offset. This technique provides continuous and accurate estimates of boundary layer air temperature profile and air/sea temperature difference. The main advantage of this technique is that the water skin temperature can be measured at different optical depths without disturbing the skin layer (magnitude order of microns). We first compare radiometric data collected during the experiment with simulations obtained by atmospheric and oceanic radiative transfer models. We then use statistical inversion techniques to estimate air temperature profiles from upward looking measurements, based on an a priori data set of about 1500 ship-based radiosonde observations. For the "well-posed" problem of air/sea temperature difference estimation, we apply a physical retrieval algorithm to the downward looking measurements, accounting for air attenuation and sea surface roughness. Then we show retrieval results and evaluate the achieved accuracy. Finally, we compare radiometric estimates with in situ measurements, discussing similarities and

  14. Measurement of Rapid Variations in Lower-Tropospheric Humidity Profiles Using Ground-Based Scanning Compact Microwave Radiometers

    NASA Astrophysics Data System (ADS)

    Sahoo, S.; Bosch-Lluis, X.; Reising, S. C.; Vivekanandan, J.

    2012-12-01

    Thermodynamic properties of the troposphere, particularly water vapor content and temperature, change in response to physical mechanisms, including frictional drag, evaporation, transpiration, heat transfer, pollutant emission and flow modification due to terrain. The planetary boundary layer (PBL) is characterized by a greater rate of change in the thermodynamic state of the atmosphere than at higher altitudes in the troposphere. Measurement of these changes, such as large horizontal gradients in water vapor and vertical profiles, provides very important data for improved weather prediction. Sensitivity studies for severe storm prediction indicate that a lack of accurate observations of water vapor densities throughout the lower troposphere limits the forecasting of severe storms. Therefore, measurements of water vapor density using microwave radiometers may help to improve accuracy of severe weather prediction. The HUMidity EXperiment 2011 (HUMEX11) was conducted to validate remote sensing of tropospheric humidity using ground-based scanning Compact Microwave Radiometers for Humidity profiling (CMR-H). Two microwave radiometers were scanned to sample an atmospheric volume at the U.S. Department of Energy (DOE)'s Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Climate Research Facility. Scientific objectives of HUMEX11 were to measure water vapor profiles in the lower troposphere with high vertical and temporal resolution and to track rapid variations in water vapor in the lowest 3 km of the troposphere. The principal reason for conducting the campaign at the SGP Climate Research Facility was the ability to compare the water vapor profile results with other measurements like ARM microwave radiometers and Raman lidar. The Raman lidar water vapor profiles were used as truth for comparison with the retrieved profiles. The study also focuses on optimizing the size of the background data set to minimize retrieval error as well as varying the

  15. Microwave Radiometer Technology Acceleration Mission (MiRaTA): Advancing Weather Remote Sensing with Nanosatellites

    NASA Astrophysics Data System (ADS)

    Cahoy, K.; Blackwell, W. J.; Bishop, R. L.; Erickson, N.; Fish, C. S.; Neilsen, T. L.; Stromberg, E. M.; Bardeen, J.; Dave, P.; Marinan, A.; Marlow, W.; Kingsbury, R.; Kennedy, A.; Byrne, J. M.; Peters, E.; Allen, G.; Burianek, D.; Busse, F.; Elliott, D.; Galbraith, C.; Leslie, V. V.; Osaretin, I.; Shields, M.; Thompson, E.; Toher, D.; DiLiberto, M.

    2014-12-01

    The Microwave Radiometer Technology Acceleration (MiRaTA) is a 3U CubeSat mission sponsored by the NASA Earth Science Technology Office (ESTO). Microwave radiometer measurements and GPS radio occultation (GPSRO) measurements of all-weather temperature and humidity provide key contributions toward improved weather forecasting. The MiRaTA mission will validate new technologies in both passive microwave radiometry and GPS radio occultation: (1) new ultra-compact and low-power technology for multi-channel and multi-band passive microwave radiometers, and (2) new GPS receiver and patch antenna array technology for GPS radio occultation retrieval of both temperature-pressure profiles in the atmosphere and electron density profiles in the ionosphere. In addition, MiRaTA will test (3) a new approach to spaceborne microwave radiometer calibration using adjacent GPSRO measurements. The radiometer measurement quality can be substantially improved relative to present systems through the use of proximal GPSRO measurements as a calibration standard for radiometric observations, reducing and perhaps eliminating the need for costly and complex internal calibration targets. MiRaTA will execute occasional pitch-up maneuvers so that the radiometer and GPSRO observations sound overlapping volumes of atmosphere through the Earth's limb. To validate system performance, observations from both microwave radiometer (MWR) and GPSRO instruments will be compared to radiosondes, global high-resolution analysis fields, other satellite observations, and to each other using radiative transfer models. Both the radiometer and GPSRO payloads, currently at TRL5 but to be advanced to TRL7 at mission conclusion, can be accommodated in a single 3U CubeSat. The current plan is to launch from an International Space Station (ISS) orbit at ~400 km altitude and 52° inclination for low-cost validation over a ~90-day mission to fly in 2016. MiRaTA will demonstrate high fidelity, well-calibrated radiometric

  16. Dual frequency microwave radiometer measurements of soil moisture for bare and vegetated rough surfaces

    NASA Technical Reports Server (NTRS)

    Lee, S. L.

    1974-01-01

    Controlled ground-based passive microwave radiometric measurements on soil moisture were conducted to determine the effects of terrain surface roughness and vegetation on microwave emission. Theoretical predictions were compared with the experimental results and with some recent airborne radiometric measurements. The relationship of soil moisture to the permittivity for the soil was obtained in the laboratory. A dual frequency radiometer, 1.41356 GHz and 10.69 GHz, took measurements at angles between 0 and 50 degrees from an altitude of about fifty feet. Distinct surface roughnesses were studied. With the roughness undisturbed, oats were later planted and vegetated and bare field measurements were compared. The 1.4 GHz radiometer was less affected than the 10.6 GHz radiometer, which under vegetated conditions was incapable of detecting soil moisture. The bare surface theoretical model was inadequate, although the vegetation model appeared to be valid. Moisture parameters to correlate apparent temperature with soil moisture were compared.

  17. Infrared Fiber Radiometer For Thermometry In Therapeutic Microwave And Radio Frequency Heating

    NASA Astrophysics Data System (ADS)

    Katzir, A.; Bowman, F.; Narciso, H.; Asfour, Y.; Zur, A.

    1987-04-01

    Hyperthermia in cancer treatment involves heating malignant tumors to 42.5-43.0°C for an extended period (e.g. 30 min) in an attempt to obtain remission. For superficial and some deep seated tumors electromagnetic (microwave or radio frequency) field induced heating is often used. One of the severe problems with this therapeutic modality is the accurate measurement of temperature in the presence of a strong electromagnetic field. We have under development an infrared fiber-radiometer system which quantifies temperatures by measuring black body emission from the surface. This radiometer is based on a non-metallic, infrared fiber probe, which can operate either in contact or in non contact modes. When the fibers are incorporated in endoscopic catheters, internal body temperatures may be measured at those sites accessible via body orifices. In preliminary investigations the radiometer worked well in a strong microwave field, with an accuracy of ±0.5°C.

  18. Geosynchronous Microwave Atmospheric Sounding Radiometer (MASR) feasibility studies. Volume 1: Management summary

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The mission of the microwave atmospheric sounding radiometer (MASR) is to collect data to aid in the observation and prediction of severe storms. The geosynchronous orbit allows the continuous atmospheric measurement needed to resolve mesoscale dynamics. The instrument may operate in conjunction with this document, Volume 1 - Management, which summarizes the highlights of final reports on both the radiometer instrument and antenna studies. The radiometer instrument summary includes a synopsis of Volume 2 - Radiometer Receiver Feasibility, including design, recommended configuration, performance estimates, and weight and power estimates. The summary of the antenna study includes a synopsis of Volume 3 - Antenna Feasibility, including preliminary design tradeoffs, performance of selected design, and details of the mechanical/thermal design.

  19. Multifrequency Aperture-Synthesizing Microwave Radiometer System (MFASMR). Volume 2: Appendix

    NASA Technical Reports Server (NTRS)

    Wiley, C. A.; Chang, M. U.

    1981-01-01

    A number of topics supporting the systems analysis of a multifrequency aperture-synthesizing microwave radiometer system are discussed. Fellgett's (multiple) advantage, interferometer mapping behavior, mapping geometry, image processing programs, and sampling errors are among the topics discussed. A FORTRAN program code is given.

  20. Design, fabrication and deployment of a miniaturized spectrometer radiometer based on MMIC technology for tropospheric water vapor profiling

    NASA Astrophysics Data System (ADS)

    Iturbide-Sanchez, Flavio

    This dissertation describes the design, fabrication and deployment of the Compact Microwave Radiometer for Humidity profiling (CMR-H). The CMR-H is a new and innovative spectrometer radiometer that is based on monolithic microwave and millimeter-wave integrated circuit (MMIC) technology and is designed for tropospheric water vapor profiling. The CMR-H simultaneously measures microwave emission at four optimally-selected frequency channels near the 22.235 GHz water vapor absorption line, constituting a new set of frequencies for the retrieval of the water vapor profile. State-of-the-art water vapor radiometers either measure at additional channels with redundant information or perform multi-frequency measurements sequentially. The fabrication of the CMR-H demonstrates the capability of MMIC technology to reduce substantially the operational power consumption and size of the RF and IF sections. Those sections comprise much of the mass and volume of current microwave receivers for remote sensing, except in the case of large antennas. The use of the compact box-horn array antenna in the CMR-H demonstrates its capability to reduce the mass and volume of microwave radiometers, while maintaining similar performance to that of commonly-used, bulky horn antennas. Due to its low mass, low volume, low power consumption, fabrication complexity and cost, the CMR-H represents a technological improvement in the design of microwave radiometers for atmospheric water vapor observations. The field test and validation of the CMR-H described in this work focuses on comparisons of measurements during two field experiments from the CMR-H and a state-of-the-art microwave radiometer, which measures only in a volume subtended by the zenith-pointing antenna's beam pattern. In contrast, the CMR-H is designed to perform volumetric scans and to function correctly as a node in a network of radiometers. Mass production of radiometers based on the CMR-H design is expected to enable the

  1. The distribution of ammonia on Jupiter from a preliminary inversion of Juno microwave radiometer data

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Ingersoll, Andrew; Janssen, Michael; Levin, Steven; Bolton, Scott; Adumitroaie, Virgil; Allison, Michael; Arballo, John; Bellotti, Amadeo; Brown, Shannon; Ewald, Shawn; Jewell, Laura; Misra, Sidharth; Orton, Glenn; Oyafuso, Fabiano; Steffes, Paul; Williamson, Ross

    2017-06-01

    The Juno microwave radiometer measured the thermal emission from Jupiter's atmosphere from the cloud tops at about 1 bar to as deep as a hundred bars of pressure during its first flyby over Jupiter (PJ1). The nadir brightness temperatures show that the Equatorial Zone is likely to be an ideal adiabat, which allows a determination of the deep ammonia abundance in the range 362-33+33 ppm. The combination of Markov chain Monte Carlo method and Tikhonov regularization is studied to invert Jupiter's global ammonia distribution assuming a prescribed temperature profile. The result shows (1) that ammonia is depleted globally down to 50-60 bars except within a few degrees of the equator, (2) the North Equatorial Belt is more depleted in ammonia than elsewhere, and (3) the ammonia concentration shows a slight inversion starting from about 7 bars to 2 bars. These results are robust regardless of the choice of water abundance.Plain Language SummaryThe distribution of ammonia gas on Jupiter's atmosphere was derived by fitting the <span class="hlt">microwave</span> spectra measured by the Juno spacecraft. The result showed that the concentration of ammonia gas in the extratropics was much less than expected and had a local minimum near 7 bars of pressure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6481201','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6481201"><span><span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Strickland, J. I.</p> <p>1985-07-02</p> <p>A <span class="hlt">radiometer</span> of the switched type has an R.F. switch connecting a detector selectively either to an antenna whose temperature (in terms of noise energy) is to be determined, or to a reference temperature, i.e. a resistive termination. The detector output is passed through an amplifier whose gain is switched between positive and negative values (for example +1 and -1) synchronously with the R.F. switch. The output of the switched gain amplifier is integrated to produce a rising voltage when the gain is positive and a falling one when it is negative. When it is positive the detector is connected to the antenna. By means of a zero crossing detector, a counter is started when this voltage crosses zero. After a fixed period, the R.F. switch and switched gain amplifier are reversed by the counter to cause the voltage to fall in accordance with the temperature of the resistive termination. The zero crossing detector and a counter measure the time interval until the voltage again crosses zero, such time interval being compared to the fixed period to provide a comparison of the unknown and reference temperatures independent of the gain of the detector, which is a valuable improvement over prior <span class="hlt">radiometers</span>. Also, by measuring time rather than voltage, the arrangement facilitates providing a digital output more suitable for storage and transmission of the data than the analog output of prior <span class="hlt">radiometers</span>. The instrument, which is relatively simple, rugged and compact, lends itself well to unattended use in monitoring the effect of rain storms on transmission in the 11.7 to 12.2 GHz band employed for satelite communication.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20060008091','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20060008091"><span>Relocation of Advanced <span class="hlt">Water</span> Vapor <span class="hlt">Radiometer</span> 1 to Deep Space Station 55</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oswald, J.; Riley, L.; Hubbard, A.; Rosenberger, H.; Tanner, A.; Keihm, S.; Jacobs, C.; Lanyi, G.; Naudet, C.</p> <p>2005-01-01</p> <p>In June of 2004, the Advanced <span class="hlt">Water</span> Vapor <span class="hlt">Radiometer</span> (AWVR) unit no. 1 was relocated to the Deep Space Station (DSS) 55 site in Madrid, Spain, from DSS 25 in Goldstone, California. This article summarizes the relocation activity and the subsequent operation and data acquisition. This activity also relocated the associated <span class="hlt">Microwave</span> Temperature Profiler (MTP) and Surface Meteorology (SurfMET) package that collectively comprise the Cassini Media Calibration System (MCS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005IPNPR.163....1O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005IPNPR.163....1O"><span>Relocation of Advanced <span class="hlt">Water</span> Vapor <span class="hlt">Radiometer</span> 1 to Deep Space Station 55</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oswald, J.; Riley, L.; Hubbard, A.; Rosenberger, H.; Tanner, A.; Keihm, S.; Jacobs, Christopher S.; Lanyi. G. E.; Naudet, C. J.</p> <p>2005-11-01</p> <p>In June of 2004, the Advanced <span class="hlt">Water</span> Vapor <span class="hlt">Radiometer</span> (AWVR) unit no. 1 was relocated to the Deep Space Station (DSS) 55 site in Madrid, Spain, from DSS 25 in Goldstone, California. This article summarizes the relocation activity and the subsequent operation and data acquisition. This activity also relocated the associated <span class="hlt">Microwave</span> Temperature Profiler (MTP) and Surface Meteorology (SurfMET) package that collectively comprise the Cassini Media Calibration System (MCS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810010835','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810010835"><span>A study of radio frequency interference with the Nimbus-7 Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kogut, J. A.</p> <p>1980-01-01</p> <p>One of the important objectives of the NIMBUS-7 Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) is to demonstrate the feasibility of all weather measurements of various ocean parameters; such as sea surface temperature (SST) and near surface wind speed (WS). These ocean parameters can be determined from multispectral measurements of ocean brightness temperatures in the <span class="hlt">microwave</span> region of the electromagnetic spectrum. These <span class="hlt">microwave</span> measurements, however, are distorted if the field of view of the SMMR antenna encounters radio transmissions from terrestrial sources. Sources of terrestrial Radio Frequency Interference (RFI) in the SMMR ocean data were identified. Its extent and characteristics over different ocean areas on the Earth were determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRD..120.1565G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRD..120.1565G"><span>Monitoring a convective winter episode of the Iberian Peninsula using a multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gascón, E.; Sánchez, J. L.; Fernández-González, S.; Hermida, L.; López, L.; García-Ortega, E.; Merino, A.</p> <p>2015-02-01</p> <p>On 4 March 2011, a heavy snowfall episode affected the central Iberian Peninsula. Under the TECOAGUA Project (aimed at the study of winter cloud masses that produce snow in the Guadarrama Mountains near Madrid), measurements using a ground-based multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (MMWR) with vertical range 10 km recorded this episode of winter convection embedded within stratiform precipitation. In contrast to radiosondes, data retrieval from the MMWR has a clear advantage for identifying hazardous weather phenomena of short duration, such as winter convective episodes. From these continuous measurements, we analyzed the behavior of variables such as temperature, surface pressure, relative humidity, liquid <span class="hlt">water</span> content, liquid <span class="hlt">water</span> path, <span class="hlt">water</span> vapor content, and integrated <span class="hlt">water</span> vapor throughout the day. The continuous measurements also permitted construction of skew-T log-P profiles every 15 min during the convective episode, indicating vertical evolution of an event with an appearance similar to a "zipper" in which temperature and dew point temperature profiles are "closed" from the surface to 400 hPa and "reopen" at the end of the event. Finally, we selected six indices of stability most suitable for the study of winter convection, namely, the Showalter index, low-topped convection index, most unstable lifted index, most unstable convective available potential energy (MUCAPE), convective inhibition, and MUCAPE level of free convection. Each of these indices has been evaluated for their capacity to warn of meteorological conditions leading to a convective heavy snowfall event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Icar..241..221L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Icar..241..221L"><span>Iapetus' near surface thermal emission modeled and constrained using Cassini RADAR <span class="hlt">Radiometer</span> <span class="hlt">microwave</span> observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Le Gall, A.; Leyrat, C.; Janssen, M. A.; Keihm, S.; Wye, L. C.; West, R.; Lorenz, R. D.; Tosi, F.</p> <p>2014-10-01</p> <p> most probably >200 J m-2 K-1 s-1/2 is inferred. This suggests a gradient in density with depth or, more likely, that the <span class="hlt">Radiometer</span> has probed the icy substrate underlying the dark layer. Furthermore, the measured thermal emission is found to arise from the upper few meters of the subsurface, which points to tholins, rather than iron oxide compounds, as the primary contaminants of the dark material. We also find that, although there is a latitudinal decrease probably related to the thinning of the dark layer away from the Equator, the CR region exhibits a high 2.2-cm emissivity, 0.87 in average, which is close to the emissivity of Phoebe, a putative source of the dark matter. In the case of RT + ST, model fitting points to a mean thermal inertia of ∼160 J m-2 K-1 s-1/2 along with the possible presence of an absorbing compound in the regolith of the bright terrains. Nevertheless, this layer is transparent enough for the <span class="hlt">Radiometer</span> to capture the seasonal contrast between the northern and southern hemispheres. Lastly, a global decline of the <span class="hlt">microwave</span> emissivity with latitude is revealed; it is probably indicative of a progressive increase of the <span class="hlt">water</span> ice content in the near surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750025495','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750025495"><span>On the determination of atmospheric path length by passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Webster, W. J., Jr.</p> <p>1975-01-01</p> <p><span class="hlt">Microwave</span> <span class="hlt">radiometer</span> techniques were evaluated for use in atmospheric path length correction of Pacific Plate Motion Experiment interferometer measurements. It is shown that passive <span class="hlt">microwave</span> radiometry allows precise measurement of the brightness temperature of the sky. It is also noted that the technological requirements of <span class="hlt">radiometers</span> are very different from the requirements of radio astronomy. The technology was used in the construction of <span class="hlt">radiometers</span> which are sufficient for use in the path length correction problem. A simulation study shows that, when combined with surface meteorology data, passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data would allow a determination of the path length correction to better than 2 cm at the zenith. By a careful choice of frequencies, a dual frequency system would allow a measurement of the path length correction to better than 4 cm at zenith angles as great as 60 deg. Because of the wide range of weather conditions to be expected for the PPME sites (which include Alaska, Hawaii and Massachusetts), it will probably be necessary to use a separate correction algorithm for each site.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.P33C2167L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.P33C2167L"><span>Retrievals of atmospheric parameters from radiances obtained by the Juno <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, C.; Ingersoll, A. P.; Janssen, M. A.</p> <p>2016-12-01</p> <p>The Juno <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (MWR) makes a north-south scan of Jupiter on every perijove pass of the spacecraft (Fig. 1). The planet is observed in six channels, at wavelengths ranging from 1.3 cm to 50 cm, the peaks of whose weighting functions range from 0.6 bars to 30 bars, respectively. Within 25 degrees of the equator each latitude band 1 degree wide is observed at 5-10 different emission angles. Intermediate processing involves conversion of electrical signals into radiances, subtraction of the side lobe contributions, and deconvolution to achieve maximum spatial resolution. After that, one wants to convert the radiances into physical parameters of the atmosphere, all as functions of latitude. The two main goals of the MWR are (1) to determine the global <span class="hlt">water</span> and ammonia abundances and (2) to document the latitude variations of <span class="hlt">water</span>, ammonia, and temperature in the subcloud regions, in effect, to observe the deep Jovian weather. Prior probability is based on the Galileo probe results at 6 degrees north latitude, VLA maps at wavelengths shorter than 7 cm, and moist adiabats calculated from assumed deep abundances of <span class="hlt">water</span> and ammonia. A complication is that ammonia dominates the <span class="hlt">microwave</span> opacity, and <span class="hlt">water</span> is detectable mainly through its effect on the temperature profile and the slope of the moist adiabat. MCMC analysis of synthetic data suggests that the radiances and limb-darkening parameters contain at most 4 pieces of information about the atmosphere at each latitude. Choosing the right parameters is the heart of the effort, and we will report on testing the choices using synthetic and real data. If we have preliminary results concerning objectives (1) and (2) above, we will share them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750008878','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750008878"><span>Soil moisture detection by Skylab's <span class="hlt">microwave</span> sensors. [<span class="hlt">radiometer</span>/scatterometer measurements of Texas</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moore, R. K.; Ulaby, F. T. (Principal Investigator); Barr, J. C.; Sobti, A.</p> <p>1974-01-01</p> <p>The author has identified the following significant results. Terrain <span class="hlt">microwave</span> backscatter and emission response to soil moisture variations were investigated using Skylab's 13.9 GHz RADSCAT (<span class="hlt">radiometer</span>/scatterometer) system. Data acquired on June 5, 1973, over a test site in west-central Texas indicated a fair degree of correlation with composite rainfall. The scan made was cross-track contiguous (CTC) with a pitch of 29.4 deg and no roll effect. Vertical polarization was employed with both <span class="hlt">radiometer</span> and scatterometer. The composite rainfall was computed according to the flood prediction technique using rainfall data supplied by weather reporting stations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750023271','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750023271"><span>A new broadband square law detector. [<span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Reid, M. S.; Gardner, R. A.; Stelzried, C. T.</p> <p>1975-01-01</p> <p>A broadband constant law detector was developed for precision power measurements, radio metric measurements, and other applications. It has a wide dynamic range and an accurate square law response. Other desirable characteristics, which are all included in a single compact unit, are: (1) high-level dc output with immunity to ground loop problems; (2) fast response times; (3) ability to insert known time constants; and (4) good thermal stability. The detector and its performance are described in detail. The detector can be operated in a programmable system with a ten-fold increase in accuracy. The use and performance of the detector in a noise-adding <span class="hlt">radiometer</span> system is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950037379&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddmr','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950037379&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddmr"><span>Angular power spectrum of the <span class="hlt">microwave</span> background anisotropy seen by the COBE differential <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wright, E. L.; Smoot, G. F.; Bennett, C. L.; Lubin, P. M.</p> <p>1994-01-01</p> <p>The angular power spectrum estimator developed by Peebles (1973) and Hauser & Peebles (1973) has been modified and applied to the 2 yr maps produced by the Cosmic Background Explorer Satellite Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (COBE DMR)). The power spectrum of the real sky has been compared to the power spectra of a large number of simulated random skies produced with noise equal to the observed noise and primordial density fluctuation power spectra of power-law form, with P(k) proportional to k(exp n). Within the limited range of spatial scales covered by the COBE DMR, corresponding to spherical harmonic indices 3 less than or = l is less than or approximately = 30, the best-fitting value of the spectral index is n = 1.25(sup +0.39 sub -0.44) with the Harrisson-Zel'dovich value n = 1 approximately 0.5 sigma below the best fit. For 3 less than or = l less than or approximately = 19, the best fit is n = 1.46(sup +0.39 sub -0.44). Comparing the COBE DMR delta-T/T at small l to the delta-T/T at l approximately = 50 from degree scale anisotropy experiments gives a smaller range of acceptable spectral indices which includes n = 1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994ApJ...436..443W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994ApJ...436..443W"><span>Angular power spectrum of the <span class="hlt">microwave</span> background anisotropy seen by the COBE differential <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wright, E. L.; Smoot, G. F.; Bennett, C. L.; Lubin, P. M.</p> <p>1994-12-01</p> <p>The angular power spectrum estimator developed by Peebles (1973) and Hauser & Peebles (1973) has been modified and applied to the 2 yr maps produced by the Cosmic Background Explorer Satellite Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (COBE DMR)). The power spectrum of the real sky has been compared to the power spectra of a large number of simulated random skies produced with noise equal to the observed noise and primordial density fluctuation power spectra of power-law form, with P(k) proportional to kn. Within the limited range of spatial scales covered by the COBE DMR, corresponding to spherical harmonic indices 3 less than or = l is less than or approximately = 30, the best-fitting value of the spectral index is n = 1.25+0.39-0.44 with the Harrisson-Zel'dovich value n = 1 approximately 0.5 sigma below the best fit. For 3 less than or = l less than or approximately = 19, the best fit is n = 1.46+0.39-0.44. Comparing the COBE DMR delta-T/T at small l to the delta-T/T at l approximately = 50 from degree scale anisotropy experiments gives a smaller range of acceptable spectral indices which includes n = 1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.6948E..0KP','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.6948E..0KP"><span>The monitoring of critical infrastructures using <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peichl, Markus; Dill, Stephan; Jirousek, Matthias; Süß, Helmut</p> <p>2008-04-01</p> <p><span class="hlt">Microwaves</span> in the range of 1-300 GHz are used in many respects for remote sensing applications. Besides radar sensors particularly passive measurement methods are used for two-dimensional imaging. The imaging of persons and critical infrastructures for security purposes is of increasing interest particularly for transportation services or public events. Personnel inspection with respect to weapons and explosives becomes an important mean concerning terrorist attacks. <span class="hlt">Microwaves</span> can penetrate clothing and a multitude of other materials and allow the detection of hidden objects by monitoring dielectric anomalies. Passive <span class="hlt">microwave</span> remote sensing allows a daytime independent non-destructive observation and examination of the objects of interest under nearly all weather conditions without artificial exposure of persons or areas. The performance of millimeter-wave radiometric imaging with respect to wide-area surveillance is investigated. Measurement results of some typical critical infrastructure scenarios are discussed. Requirements for future operational systems are outlined exploring a radiometric range equation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JInst...512001Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JInst...512001Z"><span>Modeling the frequency response of <span class="hlt">microwave</span> <span class="hlt">radiometers</span> with QUCS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zonca, A.; Roucaries, B.; Williams, B.; Rubin, I.; D'Arcangelo, O.; Meinhold, P.; Lubin, P.; Franceschet, C.; Jahn, S.; Mennella, A.; Bersanelli, M.</p> <p>2010-12-01</p> <p>Characterization of the frequency response of coherent radiometric receivers is a key element in estimating the flux of astrophysical emissions, since the measured signal depends on the convolution of the source spectral emission with the instrument band shape. Laboratory Radio Frequency (RF) measurements of the instrument bandpass often require complex test setups and are subject to a number of systematic effects driven by thermal issues and impedance matching, particularly if cryogenic operation is involved. In this paper we present an approach to modeling <span class="hlt">radiometers</span> bandpasses by integrating simulations and RF measurements of individual components. This method is based on QUCS (Quasi Universal Circuit Simulator), an open-source circuit simulator, which gives the flexibility of choosing among the available devices, implementing new analytical software models or using measured S-parameters. Therefore an independent estimate of the instrument bandpass is achieved using standard individual component measurements and validated analytical simulations. In order to automate the process of preparing input data, running simulations and exporting results we developed the Python package python-qucs and released it under GNU Public License. We discuss, as working cases, bandpass response modeling of the COFE and Planck Low Frequency Instrument (LFI) <span class="hlt">radiometers</span> and compare results obtained with QUCS and with a commercial circuit simulator software. The main purpose of bandpass modeling in COFE is to optimize component matching, while in LFI they represent the best estimation of frequency response, since end-to-end measurements were strongly affected by systematic effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720009621','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720009621"><span>Development of a satellite <span class="hlt">microwave</span> <span class="hlt">radiometer</span> to sense the surface temperature of the world oceans</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hidy, G. M.; Hall, W. F.; Hardy, W. N.; Ho, W. W.; Jones, A. C.; Love, A. W.; Vannmell, M. J.; Wang, H. H.; Wheeler, A. E.</p> <p>1972-01-01</p> <p>A proposed S-band <span class="hlt">radiometer</span> for determining the ocean surface temperature with an absolute accuracy of + or - 1 Kelvin and a resolution of + or - .1 Kelvin was placed under the Advanced Applications Flight Experiment for further development into Nimbus readiness state. The results of assessing the following are described: effects due to the state of the sea surface, effects caused by the intervening atmosphere, and effects associated with imperfections in the instrument itself. An extensive sea truth program is also described for correlation of aircraft test flight measurements or of satellite remote measurement to in-situ data. An improved <span class="hlt">radiometer</span> design is a modified Dicke-switch type with temperature stabilized, <span class="hlt">microwave</span> integrated circuit, front-end and with a pulsed injection-noise nulling system. The <span class="hlt">radiometer</span> has a multimode rectangular horn antenna with very low ohmic losses and a beam efficiency of 98% or better.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810019816','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810019816"><span>Transfer-matrices for series-type <span class="hlt">microwave</span> antenna circuits. [L-band <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmidt, R. F.</p> <p>1981-01-01</p> <p>Transfer matrices are developed which permit analysis and computer evaluation of certain series type <span class="hlt">microwave</span> antenna circuits associated with an L-Band <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (LBMR) under investigation at Goddard Space Flight Center. This <span class="hlt">radiometer</span> is one of several diverse instrument designs to be used for the determination of soil moisture, sea state, salinity, and temperature data. Four port matrix notation is used throughout for the evaluation of LBMR circuits with mismatched couplers and lossy transmission lines. Matrix parameters in examples are predicted on an impedance analysis and an assumption of an array aperture distribution. The notation presented is easily adapted to longer and more varied chains of matrices, and to matrices of larger dimension.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850014920','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850014920"><span>Studies on Physical Properties of Snow Based on Multi Channel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tsuchiya, K.; Takeda, K.</p> <p>1985-01-01</p> <p>The analysis of the data observed over a snow field with a breadboard model of MSR (<span class="hlt">microwave</span> scanning <span class="hlt">radiometer</span>) to be installed in MOS-1 (Marine Observation Satellite-1) indicates that: (1) the influence of incident angle on brightness temperature is larger in horizontal polarization component than in vertical polarization component. The effect of incident angle depends upon the property of snow with larger value for dry snow; (2) the difference of snow surface configuration consisting of artifically made parallel ditches of 5 cm depth and 5 cm width with spacing of 10 and 30 cm respectively which are oriented normal to electrical axis do not affect brightness temperature significantly; and (3) there is high negative correlation between brightness temperature and snow depth up to the depth of 70 cm which suggests that the snow depth can be measured with a two channel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> up to this depth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000038156&hterms=Discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DDiscrimination','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000038156&hterms=Discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DDiscrimination"><span>Stratiform and Convective Rain Discrimination from <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prabhakara, C.; Cadeddu, M.; Short, D. A.; Weinman, J. A.; Schols, J. L.; Haferman, J.</p> <p>1997-01-01</p> <p>A criterion based on the SSM/I observations is developed to discriminate rain into convective and stratiform types. This criterion depends on the <span class="hlt">microwave</span> polarization properties of the flat melting snow particles that fall slowly in the stratiform clouds. Utilizing this criterion and some spatial and temporal characteristics of hydrometeors in TOGA-COARE area revealed by ship borne radars, we have developed an algorithm to retrieve convective and stratiform rain rate from SSM/I data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000038156&hterms=discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddiscrimination','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000038156&hterms=discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddiscrimination"><span>Stratiform and Convective Rain Discrimination from <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prabhakara, C.; Cadeddu, M.; Short, D. A.; Weinman, J. A.; Schols, J. L.; Haferman, J.</p> <p>1997-01-01</p> <p>A criterion based on the SSM/I observations is developed to discriminate rain into convective and stratiform types. This criterion depends on the <span class="hlt">microwave</span> polarization properties of the flat melting snow particles that fall slowly in the stratiform clouds. Utilizing this criterion and some spatial and temporal characteristics of hydrometeors in TOGA-COARE area revealed by ship borne radars, we have developed an algorithm to retrieve convective and stratiform rain rate from SSM/I data.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820008288&hterms=packaging+design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dpackaging%2Bdesign','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820008288&hterms=packaging+design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dpackaging%2Bdesign"><span>Weight estimates and packaging techniques for the <span class="hlt">microwave</span> <span class="hlt">radiometer</span> spacecraft. [shuttle compatible design</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jensen, J. K.; Wright, R. L.</p> <p>1981-01-01</p> <p>Estimates of total spacecraft weight and packaging options were made for three conceptual designs of a <span class="hlt">microwave</span> <span class="hlt">radiometer</span> spacecraft. Erectable structures were found to be slightly lighter than deployable structures but could be packaged in one-tenth the volume. The tension rim concept, an unconventional design approach, was found to be the lightest and transportable to orbit in the least number of shuttle flights.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ESASP.740E.339K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ESASP.740E.339K"><span>Baltic Sea Ice Concentration Estimation Using Sentinel-1 SAR and <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karvonen, Juha</p> <p>2016-08-01</p> <p>Sea ice concentration (SIC) is an important sea ice parameter in environmental research, weather and ice forecasting and for navigation. We have developed a method for estimation of the Baltic Sea SIC using SENTINEL-1 SAR data and AMSR-2 <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (MWR). Here we present the method and first results of January 2016. Ice concentration of FMI daily ice charts has been used as reference data in this study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820008288&hterms=Packaging+Design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DPackaging%2BDesign','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820008288&hterms=Packaging+Design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DPackaging%2BDesign"><span>Weight estimates and packaging techniques for the <span class="hlt">microwave</span> <span class="hlt">radiometer</span> spacecraft. [shuttle compatible design</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jensen, J. K.; Wright, R. L.</p> <p>1981-01-01</p> <p>Estimates of total spacecraft weight and packaging options were made for three conceptual designs of a <span class="hlt">microwave</span> <span class="hlt">radiometer</span> spacecraft. Erectable structures were found to be slightly lighter than deployable structures but could be packaged in one-tenth the volume. The tension rim concept, an unconventional design approach, was found to be the lightest and transportable to orbit in the least number of shuttle flights.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920052425&hterms=sensor+technology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsensor%2Btechnology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920052425&hterms=sensor+technology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsensor%2Btechnology"><span>Development of <span class="hlt">microwave</span> <span class="hlt">radiometer</span> sensor technology for geostationary earth science platforms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Campbell, T. G.; Lawrence, R. W.; Schroeder, L. C.; Kendall, B. M.; Harrington, R. F.</p> <p>1991-01-01</p> <p>A new research and technology program has been initiated at the Langley Research Center of the National Aeronautics and Space Administration (NASA) for developing advanced, high resolution <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (HI-RES) sensors suitable for Mission to Planet Earth (MPE) remote sensing applications. The objective of this program is to provide the technology needed to enable and enhance the long-term observations, documentation, and understanding of the earth as a system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840011887','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840011887"><span>L band push broom <span class="hlt">microwave</span> <span class="hlt">radiometer</span>: Soil moisture verification and time series experiment Delmarva Peninsula</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jackson, T. J.; Shiue, J.; Oneill, P.; Wang, J.; Fuchs, J.; Owe, M.</p> <p>1984-01-01</p> <p>The verification of a multi-sensor aircraft system developed to study soil moisture applications is discussed. This system consisted of a three beam push broom L band <span class="hlt">microwave</span> <span class="hlt">radiometer</span>, a thermal infrared scanner, a multispectral scanner, video and photographic cameras and an onboard navigational instrument. Ten flights were made of agricultural sites in Maryland and Delaware with little or no vegetation cover. Comparisons of aircraft and ground measurements showed that the system was reliable and consistent. Time series analysis of <span class="hlt">microwave</span> and evaporation data showed a strong similarity that indicates a potential direction for future research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870065932&hterms=pbmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dpbmr','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870065932&hterms=pbmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dpbmr"><span>Results from the pushbroom <span class="hlt">microwave</span> <span class="hlt">radiometer</span> flights over the Konza Prairie in 1985</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmugge, T. J.; Wang, J. R.; Lawrence, R. W.</p> <p>1987-01-01</p> <p>Four flights were conducted by the NASA C-130 aircraft sensor platform bearing the 'pushbroom' <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (PBMR) over the Konza Prairie in central Kansas in 1985, in order to monitor soil surface variations. When the brightness temperature maps thus obtained were analyzed, a striking difference was noted between burned and unburned watersheds; the latter had a very high emissivity despite having saturated soils, while the former had low values that increased with the gradual drying of the soils. The lack of sensitivity for the unburned watershed is tentatively attributed to the build-up of a thatch layer by the decaying vegetation, which serves as a good <span class="hlt">microwave</span> absorber when wet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830064488&hterms=1041&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231041','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830064488&hterms=1041&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231041"><span>Heavy thunderstorms observed over land by the Nimbus 7 scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spencer, R. W.; Olson, W. S.; Martin, D. W.; Weinman, J. A.; Santek, D. A.; Wu, R.</p> <p>1983-01-01</p> <p>Brightness temperatures obtained through examination of <span class="hlt">microwave</span> data from the Nimbus 7 satellite are noted to be much lower than those expected on the strength of radiation emanating from rain-producing clouds. Very cold brightness temperature cases all coincided with heavy thunderstorm rainfall, with the cold temperatures being attributable to scattering by a layer of ice hydrometeors in the upper parts of the storms. It is accordingly suggested that brightness temperatures observed by satellite <span class="hlt">microwave</span> <span class="hlt">radiometers</span> can sometimes distinguish heavy rain over land.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20060039374&hterms=error+correction&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Derror%2Bcorrection','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20060039374&hterms=error+correction&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Derror%2Bcorrection"><span>TOPEX/POSEIDON <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (TMR): III. Wet Troposphere Range Correction Algorithm and Pre-Launch Error Budget</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Keihm, S. J.; Janssen, M. A.; Ruf, C. S.</p> <p>1993-01-01</p> <p>The sole mission function of the TOPEX/POSEIDON <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (TMR) is to provide corrections for the altimeter range errors induced by the highly variable atmospheric <span class="hlt">water</span> vapor content. The three TMR frequencies are shown to be near-optimum for measuring the vapor-induced path delay within an environment of variable cloud cover and variable sea surface flux background. After a review of the underlying physics relevant to the prediction of 5-40 GHz nadir-viewing <span class="hlt">microwave</span> brightness temperatures, we describe the development of the statistical, iterative algorithm used for the TMR retrieval of path delay. Test simulations are presented which demonstrate the uniformity of algorithm performance over a range of cloud liquid and sea surface wind speed conditions...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090040244&hterms=Jupiter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DJupiter','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090040244&hterms=Jupiter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DJupiter"><span><span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> from 0.6 to 22 GHz for Juno, a Polar Orbiter around Jupiter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pingree, Paula J.; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.; Smith, S.</p> <p>2008-01-01</p> <p>A compact instrument called the MWR (<span class="hlt">microwave</span> <span class="hlt">radiometer</span>) is under development at JPL for Juno, the next NASA new frontiers mission, scheduled to launch in 2011. It's purpose is to measure the thermal emission from Jupiter's atmosphere at six selected frequencies from 0.6 to 22 GHz, operating in direct detection mode, in order to quantify the distributions and abundances of <span class="hlt">water</span> and ammonia in Jupiter's atmosphere. The goal is to understand the previously unobserved dynamics of the sub-cloud atmosphere, and to discriminate among models for planetary formation in our solar system. as part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The receivers and control electronics are protected by a radiation-shielding enclosure on the Juno spacecraft that also provides for a benign and stable operating temperature environment. All antennas and RF transmission lines outside the vault must withstand low temperatures and the harsh radiation environment surrounding Jupiter. This paper describes the concept of the MWR instrument and presents results of one breadboard receiver channel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150008603&hterms=Jupiter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DJupiter','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150008603&hterms=Jupiter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DJupiter"><span><span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> from 0.6 to 22 GHz for Juno, A Polar Orbiter Around Jupiter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pingree, P.; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.; Smith, S.</p> <p>2008-01-01</p> <p>A compact instrument called the MWR (<span class="hlt">MicroWave</span> <span class="hlt">Radiometer</span>) is under development at JPL for Juno, the next NASA New Frontiers mission, scheduled to launch in 2011. It's purpose is to measure the thermal emission from Jupiter's atmosphere at six selected frequencies from 0.6 to 22 GHz, operating in direct detection mode, in order to quantify the distributions and abundances of <span class="hlt">water</span> and ammonia in Jupiter's atmosphere. The goal is to understand the previously unobserved dynamics of the sub-cloud atmosphere, and to discriminate among models for planetary formation in our solar system. As part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The receivers and control electronics are protected by a radiation-shielding enclosure on the Juno spacecraft that would provide a benign and stable operating temperature environment. All antennas and RF transmission lines outside the vault must withstand low temperatures and the harsh radiation environment surrounding Jupiter. This paper describes the concept of the MWR instrument and presents results of one breadboard receiver channel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040129509&hterms=sip&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsip','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040129509&hterms=sip&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsip"><span>Science Data Processing for the Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span>: Earth Observing System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goodman, H. Michael; Regner, Kathryn; Conover, Helen; Ashcroft, Peter; Wentz, Frank; Conway, Dawn; Lobl, Elena; Beaumont, Bruce; Hawkins, Lamar; Jones, Steve</p> <p>2004-01-01</p> <p>The National Aeronautics and Space Administration established the framework for the Science Investigator-led Processing Systems (SIPS) to enable the Earth science data products to be produced by personnel directly associated with the instrument science team and knowledgeable of the science algorithms. One of the first instantiations implemented for NASA was the Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> - Earth Observing System (AMSR-E) SIPS. The AMSR-E SIPS is a decentralized, geographically distributed ground data processing system composed of two primary components located in California and Alabama. Initial science data processing is conducted at Remote Sensing Systems (RSS) in Santa Rosa, California. RSS ingests antenna temperature orbit data sets from JAXA and converts them to calibrated, resampled, geolocated brightness temperatures. The brightness temperatures are sent to the Global Hydrology and Climate Center in Huntsville, Alabama, which generates the geophysical science data products (e.g., <span class="hlt">water</span> vapor, sea surface temperature, sea ice extent, etc.) suitable for climate research and applications usage. These science products are subsequently sent to the National Snow and Ice Data Center Distributed Active Archive Center in Boulder, Colorado for archival and dissemination to the at-large science community. This paper describes the organization, coordination, and production techniques employed by the AMSR-E SIPS in implementing, automating and operating the distributed data processing system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870012953','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870012953"><span>The 1982-1983 El Nino Atlas: Nimbus-7 <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liu, W. Timothy</p> <p>1987-01-01</p> <p>Monthly maps of sea surface temperature, atmospheric <span class="hlt">water</span> vapor, and surface level wind speed as measured by the Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) on the Nimbus-7 satellite for the tropical Pacific from June 1982 to October 1983, during one of the most intense El Nino Southern Oscillations (ENSO) episodes, are presented. The non-ENSO annual cycle was compiled by averaging the 1980 and 1981 data for each calendar month and was removed from monthly fields of 1982 and 1983 to reveal the anomalous distributions. The anomaly fields and part of the non-ENSO annual cycle are also presented. This study and earlier evaluations demonstrate that the Nimbus/SMMR can be used to monitor large scale and low frequency variabilities in the tropical ocean. The SMMR data support and extend conventional measurements. The variabilities of the three parameters are found to represent various aspects of ENSO related through ocean atmosphere interaction. Their simultaneous and quantitative descriptions pave the way for the derivation of ocean atmosphere latent heat exchange and further the understanding of the coupled atmospheric and oceanic thermodynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040129509&hterms=beaumont&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbeaumont','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040129509&hterms=beaumont&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbeaumont"><span>Science Data Processing for the Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span>: Earth Observing System</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goodman, H. Michael; Regner, Kathryn; Conover, Helen; Ashcroft, Peter; Wentz, Frank; Conway, Dawn; Lobl, Elena; Beaumont, Bruce; Hawkins, Lamar; Jones, Steve</p> <p>2004-01-01</p> <p>The National Aeronautics and Space Administration established the framework for the Science Investigator-led Processing Systems (SIPS) to enable the Earth science data products to be produced by personnel directly associated with the instrument science team and knowledgeable of the science algorithms. One of the first instantiations implemented for NASA was the Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> - Earth Observing System (AMSR-E) SIPS. The AMSR-E SIPS is a decentralized, geographically distributed ground data processing system composed of two primary components located in California and Alabama. Initial science data processing is conducted at Remote Sensing Systems (RSS) in Santa Rosa, California. RSS ingests antenna temperature orbit data sets from JAXA and converts them to calibrated, resampled, geolocated brightness temperatures. The brightness temperatures are sent to the Global Hydrology and Climate Center in Huntsville, Alabama, which generates the geophysical science data products (e.g., <span class="hlt">water</span> vapor, sea surface temperature, sea ice extent, etc.) suitable for climate research and applications usage. These science products are subsequently sent to the National Snow and Ice Data Center Distributed Active Archive Center in Boulder, Colorado for archival and dissemination to the at-large science community. This paper describes the organization, coordination, and production techniques employed by the AMSR-E SIPS in implementing, automating and operating the distributed data processing system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090040244&hterms=olopatadine+AL-4943A&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchany%26Ntt%3Dolopatadine%2BAL-4943A%2B0.6%2525','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090040244&hterms=olopatadine+AL-4943A&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchany%26Ntt%3Dolopatadine%2BAL-4943A%2B0.6%2525"><span><span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> from 0.6 to 22 GHz for Juno, a Polar Orbiter around Jupiter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pingree, Paula J.; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.; Smith, S.</p> <p>2008-01-01</p> <p>A compact instrument called the MWR (<span class="hlt">microwave</span> <span class="hlt">radiometer</span>) is under development at JPL for Juno, the next NASA new frontiers mission, scheduled to launch in 2011. It's purpose is to measure the thermal emission from Jupiter's atmosphere at six selected frequencies from 0.6 to 22 GHz, operating in direct detection mode, in order to quantify the distributions and abundances of <span class="hlt">water</span> and ammonia in Jupiter's atmosphere. The goal is to understand the previously unobserved dynamics of the sub-cloud atmosphere, and to discriminate among models for planetary formation in our solar system. as part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The receivers and control electronics are protected by a radiation-shielding enclosure on the Juno spacecraft that also provides for a benign and stable operating temperature environment. All antennas and RF transmission lines outside the vault must withstand low temperatures and the harsh radiation environment surrounding Jupiter. This paper describes the concept of the MWR instrument and presents results of one breadboard receiver channel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20150008603&hterms=olopatadine+AL-4943A&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchany%26Ntt%3Dolopatadine%2BAL-4943A%2B0.6%2525','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20150008603&hterms=olopatadine+AL-4943A&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchany%26Ntt%3Dolopatadine%2BAL-4943A%2B0.6%2525"><span><span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> from 0.6 to 22 GHz for Juno, A Polar Orbiter Around Jupiter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pingree, P.; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.; Smith, S.</p> <p>2008-01-01</p> <p>A compact instrument called the MWR (<span class="hlt">MicroWave</span> <span class="hlt">Radiometer</span>) is under development at JPL for Juno, the next NASA New Frontiers mission, scheduled to launch in 2011. It's purpose is to measure the thermal emission from Jupiter's atmosphere at six selected frequencies from 0.6 to 22 GHz, operating in direct detection mode, in order to quantify the distributions and abundances of <span class="hlt">water</span> and ammonia in Jupiter's atmosphere. The goal is to understand the previously unobserved dynamics of the sub-cloud atmosphere, and to discriminate among models for planetary formation in our solar system. As part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The receivers and control electronics are protected by a radiation-shielding enclosure on the Juno spacecraft that would provide a benign and stable operating temperature environment. All antennas and RF transmission lines outside the vault must withstand low temperatures and the harsh radiation environment surrounding Jupiter. This paper describes the concept of the MWR instrument and presents results of one breadboard receiver channel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1815021S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1815021S"><span>The Passive <span class="hlt">Microwave</span> Neural Network Precipitation Retrieval (PNPR) for AMSU/MHS and ATMS cross-track scanning <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sano', Paolo; Casella, Daniele; Panegrossi, Giulia; Cinzia Marra, Anna; Dietrich, Stefano</p> <p>2016-04-01</p> <p> another when an observed precipitation system extends over two or more types of surfaces. As input data, the PNPR algorithm incorporates the TBs from selected channels, and various additional TBs-derived variables. Ancillary geographical/geophysical inputs (i.e., latitude, terrain height, surface type, season) are also considered during the training phase. The PNPR algorithm outputs consist of both the surface precipitation rate (along with the information on precipitation phase: liquid, mixed, solid) and a pixel-based quality index. We will illustrate the main features of the PNPR algorithm and will show results of a verification study over Europe and Africa. The study is based on the available ground-based radar and/or rain gauge network observations over the European area. In addition, results of the comparison with rainfall products available from the NASA/JAXA Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) (over the African area) and Global Precipitation Measurement (GPM) Dual frequency Precipitation Radar (DPR) will be shown. The analysis is built upon a two-years coincidence dataset of AMSU/MHS and ATMS observations with PR (2013-2014) and DPR (2014-2015). The PNPR is developed within the EUMETSAT H/SAF program (Satellite Application Facility for Operational Hydrology and <span class="hlt">Water</span> Management), where it is used operationally towards the full exploitation of all <span class="hlt">microwave</span> <span class="hlt">radiometers</span> available in the GPM era. The algorithm will be tailored to the future European <span class="hlt">Microwave</span> Sounder (MWS) onboard the MetOp-Second Generation (MetOp-SG) satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AMT.....8.2649F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AMT.....8.2649F"><span>GROMOS-C, a novel ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> for ozone measurement campaigns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernandez, S.; Murk, A.; Kämpfer, N.</p> <p>2015-07-01</p> <p>Stratospheric ozone is of major interest as it absorbs most harmful UV radiation from the sun, allowing life on Earth. Ground-based <span class="hlt">microwave</span> remote sensing is the only method that allows for the measurement of ozone profiles up to the mesopause, over 24 hours and under different weather conditions with high time resolution. In this paper a novel ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> is presented. It is called GROMOS-C (GRound based Ozone MOnitoring System for Campaigns), and it has been designed to measure the vertical profile of ozone distribution in the middle atmosphere by observing ozone emission spectra at a frequency of 110.836 GHz. The instrument is designed in a compact way which makes it transportable and suitable for outdoor use in campaigns, an advantageous feature that is lacking in present day ozone <span class="hlt">radiometers</span>. It is operated through remote control. GROMOS-C is a total power <span class="hlt">radiometer</span> which uses a pre-amplified heterodyne receiver, and a digital fast Fourier transform spectrometer for the spectral analysis. Among its main new features, the incorporation of different calibration loads stands out; this includes a noise diode and a new type of blackbody target specifically designed for this instrument, based on Peltier elements. The calibration scheme does not depend on the use of liquid nitrogen; therefore GROMOS-C can be operated at remote places with no maintenance requirements. In addition, the instrument can be switched in frequency to observe the CO line at 115 GHz. A description of the main characteristics of GROMOS-C is included in this paper, as well as the results of a first campaign at the High Altitude Research Station at Jungfraujoch (HFSJ), Switzerland. The validation is performed by comparison of the retrieved profiles against equivalent profiles from MLS (<span class="hlt">Microwave</span> Limb Sounding) satellite data, ECMWF (European Centre for Medium-Range Weather Forecast) model data, as well as our nearby NDACC (Network for the Detection of Atmospheric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMIN31C1019R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMIN31C1019R"><span>Advanced Component Development to Enable Low-Mass, Low-Power High-Frequency <span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> for Coastal Wet-Tropospheric Correction on SWOT</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reising, S. C.; Brown, S.; Gaier, T. C.; Hoppe, D. J.; Dawson, D. E.</p> <p>2009-12-01</p> <p>Critical <span class="hlt">microwave</span> component and receiver technologies are under development to reduce the risk, cost, volume, mass, and development time for a high-frequency <span class="hlt">microwave</span> <span class="hlt">radiometer</span> needed to enable wet-tropospheric correction in the coastal zone on the NRC Decadal Survey-recommended Surface <span class="hlt">Water</span> and Ocean Topography (SWOT) Mission. Current satellite ocean altimeters include a nadir-viewing, co-located 18-37 GHz multi-channel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> to measure wet-tropospheric path delay. However, due to the diameter of the surface instantaneous fields of view (IFOV) at these frequencies, the accuracy of wet path retrievals begins to degrade at approximately 50 km from the coasts. In order to meet the needs of the recommended SWOT mission, higher-frequency <span class="hlt">microwave</span> channels will need to be added to the JASON-class <span class="hlt">radiometers</span> in order to improve retrievals of wet-tropospheric delay in coastal areas and to increase the potential for over-land retrievals. Development of a new high-frequency <span class="hlt">radiometer</span> measurement technique for SWOT requires technology developments in the following two key areas: (1) a low-power, low-mass and small-volume direct-detection millimeter-wave <span class="hlt">radiometer</span> with integrated calibration sources covering frequencies from 90 to 170 GHz that fits within the overall SWOT mission constraints, and (2) a multi-frequency feed horn covering the same frequency range. To accomplish these objectives, one can essentially scale the design of the Advanced <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (AMR) that is currently flying on the OSTM/Jason-2 altimetry mission. The MMIC-based AMR receiver combines three channels at 18.7, 23.8 and 34.0 GHz into a single unit with a single multi-frequency feed horn. The following three key component technologies are being developed to scale the AMR receiver design: a PIN-diode switch for calibration that can be integrated into the receiver front end, a high-Excess Noise Ratio (ENR) noise source and a multi-frequency feed horn. These new components</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H33F1231R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H33F1231R"><span>Advanced Component Development to Enable Low-Mass, Low-Power High-Frequency <span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> for Coastal Wet-Tropospheric Correction on SWOT</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reising, S. C.; Brown, S.; Kangaslahti, P.; Hoppe, D.; Dawson, D.; Lee, A.; Albers, D.; Montes, O.; Gaier, T.; Khayatian, B.</p> <p>2010-12-01</p> <p>Critical <span class="hlt">microwave</span> component and receiver technologies are under development to reduce the risk, cost, volume, mass, and development time for a high-frequency <span class="hlt">microwave</span> <span class="hlt">radiometer</span> needed to enable wet-tropospheric correction in the coastal zone and over land as part of the NRC Decadal Survey-recommended Surface <span class="hlt">Water</span> and Ocean Topography (SWOT) Mission. Current satellite ocean altimeters include a nadir-viewing, co-located 18-37 GHz multi-channel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> to measure wet-tropospheric path delay. However, due to the area of the instantaneous fields of view on the surface at these frequencies, the accuracy of wet path retrievals begins to degrade at approximately 50 km from the coasts. Addition of higher-frequency <span class="hlt">microwave</span> channels to the Jason-class <span class="hlt">radiometers</span> on the recommended SWOT mission will improve retrievals in coastal regions and enable retrievals over land. Specifically, high-frequency window channels at 92, 130 and 166 GHz are optimum for wet path delay retrievals in coastal regions. New, high-sensitivity, wide-bandwidth mm-wave <span class="hlt">radiometers</span> using both window and sounding channels show good potential for over-land wet-path delay retrievals. This work focuses on the design and fabrication of a prototype system consisting of: (1) a low-power, low-mass and small-volume direct-detection millimeter-wave <span class="hlt">radiometer</span> with integrated calibration sources covering frequencies from 90 to 170 GHz that fits within the overall SWOT mission constraints, and (2) a multi-frequency feed horn covering the same frequency range. Three key component technologies are under development to scale the design of the Advanced <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (AMR) on the OSTM/Jason-2 altimetry mission from 18-34 GHz to 90-170 GHz, i.e. a PIN-diode switch for calibration that can be integrated into the receiver front end, a high-Excess Noise Ratio (ENR) noise source and a single, tri-frequency feed horn. These new components are currently in the process of fabrication and testing, after</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760007470','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760007470"><span>Design data collection with Skylab <span class="hlt">microwave</span> <span class="hlt">radiometer</span>-scatterometer S-193, volume 2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moore, R. K.; Ulaby, F. T. (Principal Investigator)</p> <p>1975-01-01</p> <p>The author has identified the following significant results. Skylab S-193 <span class="hlt">radiometer</span>/scatterometer produced terrain responses with various polarizations and observation angles for cells of 100 to 400 sq km area. Classification of the observations into natural categories was achieved by K-means and spatial clustering algorithms. <span class="hlt">Microwave</span> data acquired over the Great Salt Lake Desert area by sensors aboard Skylab and Nimbus 5 indicate that the <span class="hlt">microwave</span> emission and backscatter were strongly influenced by contributions from subsurface layers of sediment saturated with brine. Correlations were noted between <span class="hlt">microwave</span> backscatter response at approximately 33 deg from scatterometer (operating at 13.9 GHz) and the configuration of ground targets in Brazil as discerned from coarse scale maps. With limited, available ground truth, these correlations were sufficient to permit the production of image-like displays which bear a marked resemblance to known terrain features in several instances.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840015921','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840015921"><span><span class="hlt">Microwave</span> <span class="hlt">radiometer</span> experiment of soil moisture sensing at BARC test site during summer 1981</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, J.; Jackson, T.; Engman, E. T.; Gould, W.; Fuchs, J.; Glazer, W.; Oneill, P.; Schmugge, T. J.; Mcmurtrey, J., III</p> <p>1984-01-01</p> <p>Soil moisture was measured by truck mounted <span class="hlt">microwave</span> <span class="hlt">radiometers</span> at the frequencies of 1.4 GHz, 5 GHz, and 10.7 GHz. The soil textures in the two test sites were different so that the soil type effect of <span class="hlt">microwave</span> radiometric response could be studied. Several fields in each test site were prepared with different surface roughnesses and vegetation covers. Ground truth on the soil moisture, temperature, and the biomass of the vegetation was acquired in support of the <span class="hlt">microwave</span> radiometric measurements. Soil bulk density for each of the fields in both test sites was sampled. The soils in both sites were measured mechanically and chemically. A tabulation of the measured data is presented and the sensors and operational problems associated with the measurements are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1349276','SCIGOV-DOEDE'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1349276"><span><span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> - UND Radiometrics MWR, John Day - Reviewed Data</span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Leo, Laura</p> <p>2017-03-31</p> <p>The present dataset contains the post-reprocessed level1 and level2 data files from November 2015 to May 2016. The original raw dataset's (mwr.z02.00) purpose was to monitor real-time profiles of temperature (K), <span class="hlt">water</span> vapor (gm-3), relative humidity (%), and liquid <span class="hlt">water</span> (gm-3) up to 10 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H11L..04O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H11L..04O"><span>Precipitation Estimation Using Combined Radar and <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Observations from GPM- Initial Studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olson, W. S.; Grecu, M.; Munchak, S. J.; McLaughlin, S. F.; Haddad, Z. S.; Kuo, K. S.; Tian, L.; Johnson, B. T.; Masunaga, H.</p> <p>2014-12-01</p> <p>In the Global Precipitation Measurement (GPM) mission, the Dual-Frequency Precipitation Radar - GPM <span class="hlt">Microwave</span> Imager (DPR-GMI) combined radar-<span class="hlt">radiometer</span> precipitation algorithm will provide, in principle, the most accurate and highest resolution estimates of surface rainfall rate and precipitation vertical structure from a spaceborne observing platform. In addition to direct applications of these precipitation estimates, they will serve as a crucial reference for cross-calibrating passive <span class="hlt">microwave</span> precipitation profile estimates from the GPM <span class="hlt">radiometer</span> constellation. And through the <span class="hlt">microwave</span> <span class="hlt">radiometer</span> estimates, the combined algorithm calibration will ultimately be propagated to GPM infrared-<span class="hlt">microwave</span> multisatellite estimates of surface rainfall. The GPM combined DPR-GMI precipitation algorithm is based upon an ensemble filtering technique. At each DPR footprint location, an initial estimate is made of the distribution of possible precipitation profiles consistent with DPR Ku reflectivity observations and a priori information regarding the intercepts of the assumed size distributions of precipitation particles and parameters describing environmental conditions. This Ku-consistent profile distribution is filtered using coincident DPR Ka reflectivities, the vertical path-integrated attenuation at Ku and Ka bands, and GMI brightness temperature observations. The resulting filtered distribution of precipitation profiles is consistent with all of the available data and a priori information; the mean of the profiles gives the best estimate of precipitation, and the standard deviation is a measure of the uncertainty of that estimate. The DPR-GMI algorithm will be evaluated by comparing estimated reflectivity and precipitation profiles against ground-based polarimetric radar data, and also by checking that the "best fit" precipitation distributions lead to forward radiative model simulations that are generally unbiased with respect to the observations. The impacts of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3663004','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3663004"><span>Topographic Effects on the Surface Emissivity of a Mountainous Area Observed by a Spaceborne <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pulvirenti, Luca; Pierdicca, Nazzareno; Marzano, Frank S.</p> <p>2008-01-01</p> <p>A simulation study to understand the influence of topography on the surface emissivity observed by a satellite <span class="hlt">microwave</span> <span class="hlt">radiometer</span> is carried out. We analyze the effects due to changes in observation angle, including the rotation of the polarization plane. A mountainous area in the Alps (Northern Italy) is considered and the information on the relief extracted from a digital elevation model is exploited. The numerical simulation refers to a radiometric image, acquired by a conically-scanning <span class="hlt">radiometer</span> similar to AMSR-E, i.e., flying at 705 km of altitude with an observation angle of 55°. To single out the impact on surface emissivity, scattering of the radiation due to the atmosphere or neighboring elevated surfaces is not considered. C and X bands, for which atmospheric effects are negligible, and Ka band are analyzed. The results indicate that the changes in the local observation angle tend to lower the apparent emissivity of a radiometric pixel with respect to the corresponding flat surface characteristics. The effect of the rotation of the polarization plane enlarges (vertical polarization), or attenuates (horizontal polarization) this decrease. By doing some simplifying assumptions for the <span class="hlt">radiometer</span> antenna, the conclusion is that the <span class="hlt">microwave</span> emissivity at vertical polarization is underestimated, whilst the opposite occurs for horizontal polarization, except for Ka band, for which both under- and overprediction may occur. A quantification of the differences with respect to a flat soil and an approximate evaluation of their impact on soil moisture retrieval are yielded. PMID:27879773</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27879773','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27879773"><span>Topographic Effects on the Surface Emissivity of a Mountainous Area Observed by a Spaceborne <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pulvirenti, Luca; Pierdicca, Nazzareno; Marzano, Frank S</p> <p>2008-03-03</p> <p>A simulation study to understand the influence of topography on the surfaceemissivity observed by a satellite <span class="hlt">microwave</span> <span class="hlt">radiometer</span> is carried out. We analyze theeffects due to changes in observation angle, including the rotation of the polarization plane.A mountainous area in the Alps (Northern Italy) is considered and the information on therelief extracted from a digital elevation model is exploited. The numerical simulation refersto a radiometric image, acquired by a conically-scanning <span class="hlt">radiometer</span> similar to AMSR-E,i.e., flying at 705 km of altitude with an observation angle of 55°. To single out the impacton surface emissivity, scattering of the radiation due to the atmosphere or neighboringelevated surfaces is not considered. C and X bands, for which atmospheric effects arenegligible, and Ka band are analyzed. The results indicate that the changes in the localobservation angle tend to lower the apparent emissivity of a radiometric pixel with respectto the corresponding flat surface characteristics. The effect of the rotation of thepolarization plane enlarges (vertical polarization), or attenuates (horizontal polarization)this decrease. By doing some simplifying assumptions for the <span class="hlt">radiometer</span> antenna, theconclusion is that the <span class="hlt">microwave</span> emissivity at vertical polarization is underestimated,whilst the opposite occurs for horizontal polarization, except for Ka band, for which bothunder- and overprediction may occur. A quantification of the differences with respect to aflat soil and an approximate evaluation of their impact on soil moisture retrieval areyielded.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JIMTW..38..292P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JIMTW..38..292P"><span><span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> for Spectral Observations of Mesospheric Carbon Monoxide at 115 GHz Over Kharkiv, Ukraine</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piddyachiy, Valeriy; Shulga, Valerii; Myshenko, Valeriy; Korolev, Alexey; Antyufeyev, Oleksandr; Shulga, Dmytro; Forkman, Peter</p> <p>2017-03-01</p> <p>We present the results of the development of high sensitivity <span class="hlt">microwave</span> <span class="hlt">radiometer</span> designed for observation of the atmospheric carbon monoxide (CO) emission lines at 115 GHz. The receiver of this <span class="hlt">radiometer</span> has the double-sideband noise temperature of 250 K at a temperature of 10°C. To date, this is the best noise performance for uncooled Schottky diode mixer receiver systems. The designed <span class="hlt">radiometer</span> was tested during the 2014-2015 period at observations of the carbon monoxide emission lines over Kharkiv, Ukraine (50° N, 36.3° E). These tests have shown the reliability of the receiver system, which allows us in the future to use designed <span class="hlt">radiometer</span> for continuous monitoring of carbon monoxide. The first observations of the atmospheric carbon monoxide spectral lines over Kharkiv have confirmed seasonal changes in the CO abundance and gave us reasons to assume the spread of the influence of the polar vortex on the state of the atmosphere up to the latitude of 50° N where our measurement system is located.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS53A1014W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS53A1014W"><span>Two-Look Polarimetric (2LP) <span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> for Ocean Vector Wind Retrieval</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wentz, F. J.; Hilburn, K. A.; Meissner, T.; Brown, S. E.</p> <p>2014-12-01</p> <p>This talk discusses the future utilization of two-look polarimetric (2LP) <span class="hlt">microwave</span> <span class="hlt">radiometers</span> for measuring the ocean surface wind vector. Potentially, these 2LP satellite <span class="hlt">radiometers</span> offer two advantages over conventional scatterometers: unambiguous wind vector retrievals and low-cost. One concept for a 2LP <span class="hlt">radiometer</span> is being developed by JPL and is called the Compact Ocean Wind Vector <span class="hlt">Radiometer</span> (COWVR). A space demonstration of COWVR is planned for 2016 timeframe. To explore the potential of 2LP <span class="hlt">radiometers</span>, we use the 11 years of WindSat observations as a testbed. We only use that portion of the WindSat swath that has both fore and aft observations. WindSat provides fully polarimetric observations (all four Stokes parameters) at 11, 19, and 37 GHz. This represents 12 independent channels for each of the two azimuth directions. A wind vector retrieval algorithm is developed to fully utilize this wide assortment of information. Since this analysis is based on actual observations, it provides a realistic picture of what to expect from future 2LP <span class="hlt">radiometers</span>. To our knowledge, this is the first time that the combination of WindSat's fore and aft observations has been fully utilized for wind vector retrievals. In our talk we compare the 2LP wind vector retrieval performance with that of single-look polarimetric <span class="hlt">radiometers</span> (i.e., WindSat standard product) and scatterometers. We provide basic statistics from a triple collocation between winds from WindSat, QuikScat, and NDBC/PMEL ocean moored buoys. The statistics include the standard deviation of the first ranked ambiguity direction, skill rate, and number of ambiguities. All available data from the common period of operation between WindSat and QuikScat (2003-2009) are used. We characterize the wind direction accuracy as a function of wind speed, and show how 2LP retrievals are able to extend the wind vector accuracy to lower wind speeds than previously considered possible for <span class="hlt">radiometers</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A31G0135N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A31G0135N"><span>Study of aerosol hygroscopicity by combination of lidar and <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Navas-Guzmán, F.; Ortiz, P.; Guerrero-Rascado, J. L.; Moreira, G.; Granados-Muñoz, M. J.; Bedoya, A.; Kaempfer, N.; Alados-Arboledas, L.</p> <p>2016-12-01</p> <p>Aerosol particles size may increase due to <span class="hlt">water</span> uptake (hygroscopic growth) altering their size distribution and their associated optical and microphysical properties under high relative humidity (RH) conditions. In this sense, RH is an essential variable in the description of aerosol-cloud interaction and hygroscopic growth studies. Global radiosonde observations provide most of the RH information required as input in weather-forecast models. However, the temporal resolution of routine observations performed by weather services is rather low. Past studies have shown that lidars can detect aerosol hygroscopic growth with promising results. However, the number of studies about aerosol hygroscopicity is limited and most of them only describe few case studies during specific field campaigns. The major limitation for that arise from the difficulty of having relative humidity profiles with a good spatial and temporal resolution in combination with aerosol profiles. In this study, we assess a multi-instrumental approach to obtain RH profiles with a reasonable good time and spatial resolution in a continuous way. For that, a combination of <span class="hlt">water</span> vapour profiles from a Raman lidar and temperature profiles from <span class="hlt">microwave</span> <span class="hlt">radiometer</span> is done in order to retrieve RH profiles. The measurements were performed during an intensive field campaign carried out at the EARLINET (European Aerosol Research Lidar Network) Granada station (37.16ºN, 3.61ºW, 680m asl, Spain) in Spring 2016. The capability of this approach to provide accurate RH profiles with reasonable spatial resolution has been evaluated by comparing with co-located radiosonde measurements. In addition, the RH profiles obtained from this methodology in combination with aerosol profiles were used to study the aerosol hygroscopic growth by means of the enhancement factors for several case studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950010624&hterms=Walnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWalnut','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950010624&hterms=Walnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWalnut"><span>Large area mapping of soil moisture using the ESTAR passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jackson, T. J.; Levine, D. M.; Swift, C. T.; Schmugge, T. J.</p> <p>1994-01-01</p> <p>Investigations designed to study land surface hydrologic-atmospheric interactions, showing the potential of L band passive <span class="hlt">microwave</span> radiometry for measuring surface soil moisture over large areas, are discussed. Satisfying the data needs of these investigations requires the ability to map large areas rapidly. With aircraft systems this means a need for more beam positions over a wider swath on each flightline. For satellite systems the essential problem is resolution. Both of these needs are currently being addressed through the development and verification of Electronically Scanned Thinned Array <span class="hlt">Radiometer</span> (ESTAR) technology. The ESTAR L band <span class="hlt">radiometer</span> was evaluated for soil moisture mapping applications in two studies. The first was conducted over the semiarid rangeland Walnut Gulch watershed located in south eastern Arizona (U.S.). The second was performed in the subhumid Little Washita watershed in south west Oklahoma (U.S.). Both tests showed that the ESTAR is capable of providing soil moisture with the same level of accuracy as existing systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930010798','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930010798"><span>The Split Window <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SWMR) for hurricane wind speed measurement from space</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Swift, Calvin T.; Black, P. G.</p> <p>1992-01-01</p> <p>The monitoring of hurricanes demands considerable resources each year by the National Oceanic and Atmospheric Administration. Even with the extensive use of satellite and airborne probing of those storms, there is still much uncertainty involved in predicting landfall for timely evacuation of people subject to the threat. The concept of the Split Window <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SWMR) is to add an additional capability of remotely measuring surface winds to hopefully improve prediction capabilities or at least define the severity of the storm while it is far from land. Some of the present science and observational needs are addressed in this report as are remote sensing limitations which impact the design of a minimal system which can be launched into low earth orbit by a low cost launch system. This study has concluded that wind speed and rain rate maps of hurricanes can be generated with an X-Band <span class="hlt">radiometer</span> system with an antenna whose aperture is 2 m on a side.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AMTD....8.3001F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AMTD....8.3001F"><span>GROMOS-C, a novel ground based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> for ozone measurement campaigns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernandez, S.; Murk, A.; Kämpfer, N.</p> <p>2015-03-01</p> <p>Stratospheric ozone is of major interest as it absorbs most of harmful UV radiation from the sun, allowing life on Earth. Ground based <span class="hlt">microwave</span> remote sensing is the only method that allows to measure ozone profiles up to the mesopause, 24 h and under different weather conditions with high time resolution. In this paper a novel ground based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> is presented. It is called GROMOS-C (GRound based Ozone MOnitoring System for Campaigns), and it has been designed to measure the vertical profile of ozone distribution in the middle atmosphere, by observing ozone emission spectra at a frequency of 110.836 GHz. The instrument is designed in a compact way which makes it transportable and suitable for outdoor use in campaigns, an advantageous feature that is lacking in present day ozone <span class="hlt">radiometers</span>. It is operated through remote control. GROMOS-C is a total power <span class="hlt">radiometer</span> which uses a preamplified heterodyne receiver, and a digital Fast Fourier Transform spectrometer for the spectral analysis. Among its main new features stands out the incorporation of different calibration loads, including a noise diode and a new type of blackbody target specifically designed for this instrument, based on Peltier elements. The calibration scheme does not depend on the use of liquid nitrogen, therefore GROMOS-C can be operated at remote places with no maintenance requirements. In addition the instrument can be switched in frequency to observe the CO line at 115 GHz. A description of the main characteristics of GROMOS-C is included in this paper, as well as the results of a first campaign at the High Altitude Research Station in Jungfraujoch (HFSJ), Switzerland. The validation is performed by comparison of the retrieved profiles against equivalent profiles from MLS satellite data, ECMWF model data, as well as our nearby NDACC ozone <span class="hlt">radiometer</span> measuring at Bern.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.H23G1368R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.H23G1368R"><span>Development of Low-Mass, Low-Power High-Frequency <span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> to Improve Coastal and Enable Over-Land Wet-Tropospheric Correction for SWOT</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reising, S. C.; Kangaslahti, P.; Brown, S.; Dawson, D.; Lee, A.; Albers, D.; Hoppe, D.; Montes, O.; Gaier, T.; Khayatian, B.</p> <p>2011-12-01</p> <p>Current satellite ocean altimeters include nadir-viewing, co-located 18-37 GHz multi-channel <span class="hlt">microwave</span> <span class="hlt">radiometers</span> to measure wet-tropospheric path delay. Due to the area of the surface instantaneous fields of view (IFOV) at these frequencies, the accuracy of wet path retrievals begins to degrade at approximately 40 km from the coasts. Higher-frequency <span class="hlt">radiometers</span> with internal calibration are under development to assess their suitability as part of the Surface <span class="hlt">Water</span> and Ocean Topography (SWOT) accelerated Tier-2 mission recommended by the National Research Council's Earth Science Decadal Survey and planned for launch in 2020. The addition of these high-frequency <span class="hlt">radiometers</span> to current Jason-class <span class="hlt">radiometers</span> is expected to improve retrievals of wet-tropospheric delay in coastal areas and to increase the potential for over-land retrievals. Specifically, high-frequency window channels at 92, 130 and 166 GHz are optimum for wet path delay retrievals in coastal regions. New, high-sensitivity, wide-bandwidth mm-wave <span class="hlt">radiometers</span> using both window and sounding channels show good potential for over-land wet-path delay retrievals. Critical <span class="hlt">microwave</span> component and receiver technologies are under development to reduce the risk, cost, volume, mass, and development time for high-frequency <span class="hlt">microwave</span> <span class="hlt">radiometers</span>. This project focuses on the design and fabrication of a prototype system consisting of : (1) low-power, low-mass and small-volume direct-detection millimeter-wave <span class="hlt">radiometers</span> with integrated calibration sources operating from 90 to 170 GHz that fit within the overall SWOT mission constraints, and (2) a multi-frequency feed horn covering the same frequency range. The three key component technologies under development to achieve these objectives are PIN-diode switches for internal calibration that can be integrated into the receiver front end, high-Excess Noise Ratio (ENR) noise sources and a single, tri-frequency feed horn. These new components are being integrated into</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000074793&hterms=doiron&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddoiron','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000074793&hterms=doiron&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddoiron"><span>A Preview of AMSR: Airborne C-band <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (ACMR) Observations from SGP99</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kim, Edward; Doiron, Terence; Principe, Caleb; Gong, Lei; Shiue, James</p> <p>2000-01-01</p> <p>Although L-band is generally considered ideal for passive <span class="hlt">microwave</span> sensing of soil moisture, near-future satellite observing systems such as Advanced Mechanically Scanned <span class="hlt">Radiometer</span> (AMSR) will provide C-band data for several years before any L-band data might become available. The Southern Great Plains'99 (SGP99) Experiment was designed to generate C-band observations suitable for testing and refinement of AMSR-era soil moisture retrieval algorithms. C-band data collected using the Airborne C-band <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (ACMR), a new high-accuracy NASA/GSFC instrument, clearly demonstrated a strong response to a 9-day drydown event as well as to differences between the northern (cooler & wetter) and southern (warmer & dryer) areas covered by the P-3 flights. For example, the H-polarized brightness temperatures observed during the first three days of the drydown increased up to 50 K in the northern areas. These observations represent a preview of what we can expect from AMSR, albeit at 3-km spatial resolution vs. approximately 60 km for AMSR. Initial results of soil-vegetation <span class="hlt">microwave</span> modeling will also be presented to estimate the relative contributions of soil physical temperature, canopy physical temperature, soil moisture, and canopy moisture. Significant radio-frequency interference (RFI) was evident during the experiment, and amelioration strategies will be discussed. The net effect of RFI (an upward bias in brightnesses) when averaged over an AMSR footprint is expected to be more subtle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870057750&hterms=weather+types&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dweather%2Btypes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870057750&hterms=weather+types&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dweather%2Btypes"><span>A <span class="hlt">microwave</span> <span class="hlt">radiometer</span> weather-correcting sea ice algorithm</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Walters, J. M.; Ruf, C.; Swift, C. T.</p> <p>1987-01-01</p> <p>A new algorithm for estimating the proportions of the multiyear and first-year sea ice types under variable atmospheric and sea surface conditions is presented, which uses all six channels of the SMMR. The algorithm is specifically tuned to derive sea ice parameters while accepting error in the auxiliary parameters of surface temperature, ocean surface wind speed, atmospheric <span class="hlt">water</span> vapor, and cloud liquid <span class="hlt">water</span> content. Not only does the algorithm naturally correct for changes in these weather conditions, but it retrieves sea ice parameters to the extent that gross errors in atmospheric conditions propagate only small errors into the sea ice retrievals. A preliminary evaluation indicates that the weather-correcting algorithm provides a better data product than the 'UMass-AES' algorithm, whose quality has been cross checked with independent surface observations. The algorithm performs best when the sea ice concentration is less than 20 percent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/83172','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/83172"><span>Stratus cloud measurements with a K{sub {alpha}}-band Doppler radar and a <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Frisch, A.S.; Fairall, C.W.; Snider, J.B.; Lenschow, D.H.</p> <p>1995-04-01</p> <p>The goal of the Atlantic Stratocumulus Transition Experiment (ASTEX) held in the North Atlantic during June 1992 was to determine the physical reasons for the transition from stratocumulus to broken clouds. Some possible reasons for this transition were such things as cloud top entrainment instability and the decoupling effects of drizzle. As part of this experiment, the Environmental Technology Laboratory`s cloud sensing Doppler radar and three-channel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> were deployed in the island of Porto Santo in the Madeira Islands of Portugal along with a carbon dioxide Doppler lider. Drizzle properties in stratus were examined using a log-normal droplet distribution model that related the model`s three parameters to the first three Doppler spectral moments of the cloud radar. With these moments, we are then able to compute the drizzle droplet concentration, modal radius, liquid <span class="hlt">water</span>, and liquid <span class="hlt">water</span> flux as a function of height.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830042576&hterms=measurement+length&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmeasurement%2Blength','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830042576&hterms=measurement+length&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmeasurement%2Blength"><span>Selection of optimum frequencies for atmospheric electric path length measurement by satellite-borne <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pandey, P. C.; Kakar, R. K.</p> <p>1983-01-01</p> <p>Numerical experiments using regressions by leaps and bounds have been performed to determine the optimum frequencies for satellite-borne <span class="hlt">microwave</span> <span class="hlt">radiometers</span> to estimate atmospheric electrical path length over the sea. The frequency range 5-40 GHz was searched. The effect of surface wind speed, sea surface temperature, and clouds was considered in the optimum frequency selection. The analysis indicates that approximately 0.6-cm rms accuracy is possible for one-way path length measurement using a proper pair of frequencies. The best two-channel subset selected by the leaps and bounds techniques is (16.0, 21.0) GHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20070031192&hterms=combined+heating&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcombined%2Bheating','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20070031192&hterms=combined+heating&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcombined%2Bheating"><span>Bayesian Estimation of Precipitation from Satellite Passive <span class="hlt">Microwave</span> Observations Using Combined Radar-<span class="hlt">Radiometer</span> Retrievals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grecu, Mircea; Olson, William S.</p> <p>2006-01-01</p> <p>Precipitation estimation from satellite passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> observations is a problem that does not have a unique solution that is insensitive to errors in the input data. Traditionally, to make this problem well posed, a priori information derived from physical models or independent, high-quality observations is incorporated into the solution. In the present study, a database of precipitation profiles and associated brightness temperatures is constructed to serve as a priori information in a passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> algorithm. The precipitation profiles are derived from a Tropical Rainfall Measuring Mission (TRMM) combined radar <span class="hlt">radiometer</span> algorithm, and the brightness temperatures are TRMM <span class="hlt">Microwave</span> Imager (TMI) observed. Because the observed brightness temperatures are consistent with those derived from a radiative transfer model embedded in the combined algorithm, the precipitation brightness temperature database is considered to be physically consistent. The database examined here is derived from the analysis of a month-long record of TRMM data that yields more than a million profiles of precipitation and associated brightness temperatures. These profiles are clustered into a tractable number of classes based on the local sea surface temperature, a <span class="hlt">radiometer</span>-based estimate of the echo-top height (the height beyond which the reflectivity drops below 17 dBZ), and brightness temperature principal components. For each class, the mean precipitation profile, brightness temperature principal components, and probability of occurrence are determined. The precipitation brightness temperature database supports a <span class="hlt">radiometer</span>-only algorithm that incorporates a Bayesian estimation methodology. In the Bayesian framework, precipitation estimates are weighted averages of the mean precipitation values corresponding to the classes in the database, with the weights being determined according to the similarity between the observed brightness temperature principal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20070031192&hterms=bayesian&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D40%26Ntt%3Dbayesian','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20070031192&hterms=bayesian&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D40%26Ntt%3Dbayesian"><span>Bayesian Estimation of Precipitation from Satellite Passive <span class="hlt">Microwave</span> Observations Using Combined Radar-<span class="hlt">Radiometer</span> Retrievals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grecu, Mircea; Olson, William S.</p> <p>2006-01-01</p> <p>Precipitation estimation from satellite passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> observations is a problem that does not have a unique solution that is insensitive to errors in the input data. Traditionally, to make this problem well posed, a priori information derived from physical models or independent, high-quality observations is incorporated into the solution. In the present study, a database of precipitation profiles and associated brightness temperatures is constructed to serve as a priori information in a passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> algorithm. The precipitation profiles are derived from a Tropical Rainfall Measuring Mission (TRMM) combined radar <span class="hlt">radiometer</span> algorithm, and the brightness temperatures are TRMM <span class="hlt">Microwave</span> Imager (TMI) observed. Because the observed brightness temperatures are consistent with those derived from a radiative transfer model embedded in the combined algorithm, the precipitation brightness temperature database is considered to be physically consistent. The database examined here is derived from the analysis of a month-long record of TRMM data that yields more than a million profiles of precipitation and associated brightness temperatures. These profiles are clustered into a tractable number of classes based on the local sea surface temperature, a <span class="hlt">radiometer</span>-based estimate of the echo-top height (the height beyond which the reflectivity drops below 17 dBZ), and brightness temperature principal components. For each class, the mean precipitation profile, brightness temperature principal components, and probability of occurrence are determined. The precipitation brightness temperature database supports a <span class="hlt">radiometer</span>-only algorithm that incorporates a Bayesian estimation methodology. In the Bayesian framework, precipitation estimates are weighted averages of the mean precipitation values corresponding to the classes in the database, with the weights being determined according to the similarity between the observed brightness temperature principal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040161491&hterms=land+temperature+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dland%2Btemperature%2Bnear%2Bwater','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040161491&hterms=land+temperature+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dland%2Btemperature%2Bnear%2Bwater"><span>A Model for Estimation of Rain Rate on Tropical Land from TRMM <span class="hlt">Microwave</span> Imager <span class="hlt">Radiometer</span> Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.; Kim, Kyu-Myong</p> <p>2004-01-01</p> <p>Over the tropical land regions observations of the 85 GHz brightness temperature (T(sub 85v)) made by the TRMM <span class="hlt">Microwave</span> Imager (TMI) <span class="hlt">radiometer</span> when analyzed with the help of rain rate (R(sub pR)) deduced from the TRMM Precipitation Radar (PR) indicate that there are two maxima in rain rate. One strong maximum occurs when T(sub 85) has a value of about 220 K and the other weaker one when T(sub 85v) is much colder approx. 150 K. Together with the help of earlier studies based on airborne Doppler Radar observations and radiative transfer theoretical simulations, we infer the maximum near 220 K is a result of relatively weak scattering due to super cooled rain drops and <span class="hlt">water</span> coated ice hydrometeors associated with a developing thunderstorm (Cb) that has a strong updraft. The other maximum is associated with strong scattering due to ice particles that are formed when the updraft collapses and the rain from the Cb is transit2oning from convective type to stratiform type. Incorporating these ideas and with a view to improve the estimation of rain rate from existing operational method applicable to the tropical land areas, we have developed a rain retrieval model. This model utilizes two parameters, that have a horizontal scale of approx. 20km, deduced from the TMI measurements at 19, 21 and 37 GHz (T(sub 19v), T(sub 21v), T(sub 37v). The third parameter in the model, namely the horizontal gradient of brightness temperature within the 20 km scale, is deduced from TMI measurements at 85 GHz. Utilizing these parameters our retrieval model is formulated to yield instantaneous rain rate on a scale of 20 km and seasonal average on a mesoscale that agree well with that of the PR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040161491&hterms=rain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Drain','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040161491&hterms=rain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Drain"><span>A Model for Estimation of Rain Rate on Tropical Land from TRMM <span class="hlt">Microwave</span> Imager <span class="hlt">Radiometer</span> Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.; Kim, Kyu-Myong</p> <p>2004-01-01</p> <p>Over the tropical land regions observations of the 85 GHz brightness temperature (T(sub 85v)) made by the TRMM <span class="hlt">Microwave</span> Imager (TMI) <span class="hlt">radiometer</span> when analyzed with the help of rain rate (R(sub pR)) deduced from the TRMM Precipitation Radar (PR) indicate that there are two maxima in rain rate. One strong maximum occurs when T(sub 85) has a value of about 220 K and the other weaker one when T(sub 85v) is much colder approx. 150 K. Together with the help of earlier studies based on airborne Doppler Radar observations and radiative transfer theoretical simulations, we infer the maximum near 220 K is a result of relatively weak scattering due to super cooled rain drops and <span class="hlt">water</span> coated ice hydrometeors associated with a developing thunderstorm (Cb) that has a strong updraft. The other maximum is associated with strong scattering due to ice particles that are formed when the updraft collapses and the rain from the Cb is transit2oning from convective type to stratiform type. Incorporating these ideas and with a view to improve the estimation of rain rate from existing operational method applicable to the tropical land areas, we have developed a rain retrieval model. This model utilizes two parameters, that have a horizontal scale of approx. 20km, deduced from the TMI measurements at 19, 21 and 37 GHz (T(sub 19v), T(sub 21v), T(sub 37v). The third parameter in the model, namely the horizontal gradient of brightness temperature within the 20 km scale, is deduced from TMI measurements at 85 GHz. Utilizing these parameters our retrieval model is formulated to yield instantaneous rain rate on a scale of 20 km and seasonal average on a mesoscale that agree well with that of the PR.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.A23K..06U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.A23K..06U"><span>Improvements to Stepped Frequency <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Real-time Tropical Cyclone Products</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uhlhorn, E. W.; Klotz, B.</p> <p>2012-12-01</p> <p>With the installation of C-band stepped frequency <span class="hlt">microwave</span> <span class="hlt">radiometers</span> (SFMR) on Air Force Reserve Command WC-130J hurricane reconnaissance aircraft, the SFMR has assumed a prominent role for operational measurement of surface winds, and thus, hurricane intensity estimation. The current SFMR wind retrieval algorithm was developed from GPS dropwindsonde surface wind measurements, and has been successfully implemented across all SFMR-equipped aircraft. The algorithm improvements were specifically targeted at improving surface wind accuracy at hurricane force conditions (> 65 kts, 33 m/s), especially within the eyewall, although the SFMR surface wind vs. emissivity geophysical model function was developed over a broad range of wind speeds (10-140 kts, 5-70 m/s) with the expectation that the hurricane wind field could be readily measured in general. Due to the significant <span class="hlt">microwave</span> absorption by precipitation, a by-product of the wind retrieval process is an estimate of the path-averaged rain rate (in actuality, the rain <span class="hlt">water</span> content). An SFMR surface wind speed high bias in strong precipitation has recently been quantified and is particularly evident at weak-to-moderate wind speeds (<65 kts, 33 m/s) and large rain rates (>20 mm/hr), which has important implications for identifying tropical systems at the depression and storm stages, and additionally for observing significant outer wind radii. A major reason for this wind bias is due to an inaccurate rain absorption model that was used to develop the current surface emissivity vs. wind speed geophysical model function. Observations now suggest that the rain-induced absorption is significantly overestimated by the model, resulting in underestimated rain rate values. With the wind speed bias identified, the rain absorption component of the SFMR geophysical model function is addressed to provide an improved rain rate product. This new absorption model is developed by relating SFMR excess brightness temperature</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930063681&hterms=Walnut&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DWalnut','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930063681&hterms=Walnut&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DWalnut"><span>Soil moisture verification study of the ESTAR <span class="hlt">microwave</span> <span class="hlt">radiometer</span> - Walnut Gulch, AZ 1991</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jackson, T. J.; Le Vine, D. M.; Griffis, A.; Goodrich, D. C.; Schmugge, T. J.; Swift, C. T.; O'Neill, P. E.; Roberts, R. R.; Parry, R.</p> <p>1992-01-01</p> <p>The application of an electronically steered thinned array L-band <span class="hlt">radiometer</span> (ESTAR) for soil moisture mapping is investigated over the arid rangeland Walnut Gulch Watershed. Antecedent rainfall and evaporation for the flights are very different and result in a wide range of soil moisture conditions. The high spatial variability of rainfall events within this region results in moisture conditions with dramatic spatial patterns. Sensor performance is verified using two approaches. <span class="hlt">Microwave</span> data are used in conjunction with a <span class="hlt">microwave</span> emission model to predict soil moisture. These predictions are compared to ground observations of soil moisture. A second verification is possible using an extensive data set. Both tests showed that the ESTAR is capable of providing soil moisture with the same level of accuracy as existing systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860044376&hterms=precipitation+index&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dprecipitation%2Bindex','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860044376&hterms=precipitation+index&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dprecipitation%2Bindex"><span>Correlations between Nimbus-7 Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> data and an antecedent precipitation index</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilke, G. D.; Mcfarland, M. J.</p> <p>1986-01-01</p> <p>Passive <span class="hlt">microwave</span> brightness temperatures from the Nimbus-7 Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) can be used to infer the soil moisture content over agricultural areas such as the southern Great Plains of the United States. A linear regression analysis between three transforms of the five dual polarized SMMR wavelengths of 0.81, 1.36, 1.66, 2.80 and 4.54 cm and an antecedent precipitation index representing the precipitation history showed correlation coefficients greater than 0.90 for pixel aggregates of 25-50 km. The use of surface air temperatures to approximate the temperature of the emitting layer was not required to obtain high correlation coefficients between the transforms and the antecedent precipitation index.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23338200','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23338200"><span>Errors from Rayleigh-Jeans approximation in satellite <span class="hlt">microwave</span> <span class="hlt">radiometer</span> calibration systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Weng, Fuzhong; Zou, Xiaolei</p> <p>2013-01-20</p> <p>The advanced technology <span class="hlt">microwave</span> sounder (ATMS) onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite is a total power <span class="hlt">radiometer</span> and scans across the track within a range of ±52.77° from nadir. It has 22 channels and measures the <span class="hlt">microwave</span> radiation at either quasi-vertical or quasi-horizontal polarization from the Earth's atmosphere. The ATMS sensor data record algorithm employed a commonly used two-point calibration equation that derives the earth-view brightness temperature directly from the counts and temperatures of warm target and cold space, and the earth-scene count. This equation is only valid under Rayleigh-Jeans (RJ) approximation. Impacts of RJ approximation on ATMS calibration biases are evaluated in this study. It is shown that the RJ approximation used in ATMS radiometric calibration results in errors on the order of 1-2 K. The error is also scene count dependent and increases with frequency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870007677','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870007677"><span>Evaluation of geophysical parameters measured by the Nimbus-7 <span class="hlt">microwave</span> <span class="hlt">radiometer</span> for the TOGA Heat Exchange Project</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Liu, W. Timothy; Mock, Donald R.</p> <p>1986-01-01</p> <p>The data distributed by the National Space Science Data Center on the Geophysical parameters of precipitable <span class="hlt">water</span>, sea surface temperature, and surface-level wind speed, measured by the Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) on Nimbus-7, are evaluated with in situ measurements between Jan. 1980 and Oct. 1983 over the tropical oceans. In tracking annual cycles and the 1982-83 E1 Nino/Southern Oscillation episode, the <span class="hlt">radiometer</span> measurements are coherent with sea surface temperatures and surface-level wind speeds measured at equatorial buoys and with precipitable <span class="hlt">water</span> derived from radiosonde soundings at tropical island stations. However, there are differences between SMMR and in situ measurements. Corrections based on radiosonde and ship data were derived supplementing correction formulae suggested in the databook. This study is the initial evaluation of the data for quantitative description of the 1982-83 E1 Nino/Southern Oscillation episode. It paves the way for determination of the ocean-atmosphere moisture and latent heat exchanges, a priority of the Tropical Ocean and Global Atmosphere (TOGA) Heat Exchange Program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850060314&hterms=strategies+location&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dstrategies%2Blocation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850060314&hterms=strategies+location&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dstrategies%2Blocation"><span>Optimum strategies and performance for the remote sensing of path-delay using ground-based <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gary, B. L.; Janssen, M. A.; Keihm, S. J.</p> <p>1985-01-01</p> <p>Computer simulations were used to study the accuracy of remotely sensed <span class="hlt">microwave</span> <span class="hlt">radiometer</span> measurements of excess radio propagation path delay due to atmospheric <span class="hlt">water</span> vapor. A number of strategies were investigated for remote sensing of path delay in order to define baseline parameters for the design of <span class="hlt">water</span> vapor <span class="hlt">radiometers</span> (WVRs) in geodetic applications. Strategies were judged according to their retrieval performance in a variety of climatological regions. An observing approach using the frequency 20.7/22.2/31.4 Gz was found to be close to optimum. A statistical retrieval approach using retrieval coefficients stratified for clear and cloudy weather was identified as a substantial improvement over conventional single-set all-weather retrieval strategies. It is shown that a reasonably well optimized WVR with an estimated calibration uncetainty of 0.5 K can achieve an overall retrieval performance of 0.27 cm in clear weather; and 0.51 cm in cloudy weather. The weather-averaged retrieval performance for individual locations was found to vary by no more than 14 percent from the average for all locations despite a mean path delay of 5 to 26 cm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4934332','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4934332"><span><span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> for Fire Detection in Trains: Theory and Feasibility Study †</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Alimenti, Federico; Roselli, Luca; Bonafoni, Stefania</p> <p>2016-01-01</p> <p>This paper introduces the theory of fire detection in moving vehicles by <span class="hlt">microwave</span> <span class="hlt">radiometers</span>. The system analysis is discussed and a feasibility study is illustrated on the basis of two implementation hypotheses. The basic idea is to have a fixed <span class="hlt">radiometer</span> and to look inside the glass windows of the wagon when it passes in front of the instrument antenna. The proposed sensor uses a three-pixel multi-beam configuration that allows an image to be formed by the movement of the train itself. Each pixel is constituted by a direct amplification <span class="hlt">microwave</span> receiver operating at 31.4 GHz. At this frequency, the antenna can be a 34 cm offset parabolic dish, whereas a 1 K brightness temperature resolution is achievable with an overall system noise figure of 6 dB, an observation bandwidth of 2 GHz and an integration time of 1 ms. The effect of the detector noise is also investigated and several implementation hypotheses are discussed. The presented study is important since it could be applied to the automatic fire alarm in trains and moving vehicles with dielectric wall/windows. PMID:27322280</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27322280','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27322280"><span><span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> for Fire Detection in Trains: Theory and Feasibility Study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alimenti, Federico; Roselli, Luca; Bonafoni, Stefania</p> <p>2016-06-17</p> <p>This paper introduces the theory of fire detection in moving vehicles by <span class="hlt">microwave</span> <span class="hlt">radiometers</span>. The system analysis is discussed and a feasibility study is illustrated on the basis of two implementation hypotheses. The basic idea is to have a fixed <span class="hlt">radiometer</span> and to look inside the glass windows of the wagon when it passes in front of the instrument antenna. The proposed sensor uses a three-pixel multi-beam configuration that allows an image to be formed by the movement of the train itself. Each pixel is constituted by a direct amplification <span class="hlt">microwave</span> receiver operating at 31.4 GHz. At this frequency, the antenna can be a 34 cm offset parabolic dish, whereas a 1 K brightness temperature resolution is achievable with an overall system noise figure of 6 dB, an observation bandwidth of 2 GHz and an integration time of 1 ms. The effect of the detector noise is also investigated and several implementation hypotheses are discussed. The presented study is important since it could be applied to the automatic fire alarm in trains and moving vehicles with dielectric wall/windows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19750049721&hterms=new+product+development+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dnew%2Bproduct%2Bdevelopment%2Bprocess','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19750049721&hterms=new+product+development+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dnew%2Bproduct%2Bdevelopment%2Bprocess"><span>Sensor development in the Shuttle era. [infrared temperature sounders and <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gerding, R. B.; Mantarakis, P. Z.; Webber, D. S.</p> <p>1975-01-01</p> <p>The use of the Space Shuttle in the development of earth observation sensors is examined. Two sensor classes are selected for case histories: infrared temperature sounders and <span class="hlt">microwave</span> <span class="hlt">radiometers</span>. The most significant finding in each of the developmental studies of these two sensor classes is considered to be the feasibility and value of using the Shuttle/Spacelab as a test vehicle for the operation in space of a versatile multimode experimental sensor. The Shuttle Electrically Scanned <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> and the Shuttle Infrared Interferometer are found to be the most effective instruments in this context. The Shuttle/Spacelab Sortie mission characteristics provide opportunities for new approaches to the development of sensors, using the Shuttle as a test vehicle to improve the efficiency of the process with respect to time, cost, and/or quality of the final product. As for crew functions, the short-term Spacelab mission requires some near real-time evaluation of data quality and sensor function in order to insure efficient data collection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790007849&hterms=measure+temperature+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmeasure%2Btemperature%2Bwater','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790007849&hterms=measure+temperature+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmeasure%2Btemperature%2Bwater"><span>DSN <span class="hlt">water</span> vapor <span class="hlt">radiometer</span> development: Recent work, 1978</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Batelaan, P. D.; Slobin, S. D.</p> <p>1978-01-01</p> <p>A <span class="hlt">water</span> vapor <span class="hlt">radiometer</span> (WVR) was developed that measures the atmospheric noise temperature at two different frequencies near 22 GHz. These noise temperature are used in empirical-theoretical equations that yield tropospheric range delay, in centimeters, through the atmosphere along the beam of the WVR. This range correction is then applied, as needed, to measurements concerning spacecraft range and to VLBI baseline determinations. The WVR design and calibration techniques are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812060N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812060N"><span>Validation of stratospheric temperature profiles from a ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> with other techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Navas, Francisco; Kämpfer, Niklaus; Haefele, Alexander; Keckhut, Philippe; Hauchecorne, Alain</p> <p>2016-04-01</p> <p>Vertical profiles of atmospheric temperature trends has become recognized as an important indicator of climate change, because different climate forcing mechanisms exhibit distinct vertical warming and cooling patterns. For example, the cooling of the stratosphere is an indicator for climate change as it provides evidence of natural and anthropogenic climate forcing just like surface warming. Despite its importance, our understanding of the observed stratospheric temperature trend and our ability to test simulations of the stratospheric response to emissions of greenhouse gases and ozone depleting substances remains limited. One of the main reason is because stratospheric long-term datasets are sparse and obtained trends differ from one another. Different techniques allow to measure stratospheric temperature profiles as radiosonde, lidar or satellite. The main advantage of <span class="hlt">microwave</span> <span class="hlt">radiometers</span> against these other instruments is a high temporal resolution with a reasonable good spatial resolution. Moreover, the measurement at a fixed location allows to observe local atmospheric dynamics over a long time period, which is crucial for climate research. This study presents an evaluation of the stratospheric temperature profiles from a newly ground-based <span class="hlt">microwave</span> temperature <span class="hlt">radiometer</span> (TEMPERA) which has been built and designed at the University of Bern. The measurements from TEMPERA are compared with the ones from other different techniques such as in-situ (radiosondes), active remote sensing (lidar) and passive remote sensing on board of Aura satellite (MLS) measurements. In addition a statistical analysis of the stratospheric temperature obtained from TEMPERA measurements during four years of data has been performed. This analysis evidenced the capability of TEMPERA <span class="hlt">radiometer</span> to monitor the temperature in the stratosphere for a long-term. The detection of some singular sudden stratospheric warming (SSW) during the analyzed period shows the necessity of these</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H24C..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H24C..05M"><span>Characterizing L-band Radio-Frequency Interference (RFI) Using SMAP <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mohammed, P.; Piepmeier, J. R.; Bringer, A.; Johnson, J. T.; Soldo, Y.; de Matthaeis, P.</p> <p>2016-12-01</p> <p>The L-band <span class="hlt">microwave</span> <span class="hlt">radiometer</span> on NASA's Soil Moisture Active Passive (SMAP) satellite measures electromagnetic radiation upwelling from Earth within the 1400-1427 MHz band. This relatively low <span class="hlt">microwave</span> frequency is used to achieve penetration through vegetation and first few centimeters of soil. This frequency band is specifically selected, however, because it is exclusively allocated, on a primary basis, to passive sensing in the Earth Exploration Satellite and Radio Astronomy Services by international treaty. Thus, local administrations prohibit intentional transmissions within the band, and any non-natural signal in this band is considered to be radio-frequency interference (RFI). The SMAP <span class="hlt">radiometer</span> has an advanced <span class="hlt">radiometer</span> receiver providing time, frequency, polarization, and statistical diversity information on observed signals for RFI detection and filtering. Here we use this signal information to characterize the RFI environmental on local, regional, and global bases. RFI environment assessment is of interest for several reasons: 1) Reporting instances of interference harmful to SMAP performance to the appropriate regulators; 2) Informing spectrum managers and regulators of the state of the spectrum; and 3) Alerting SMAP users and future developers of trouble spots. We find the RF environment is highly variable around the globe. Global maps of RFI rate-of-occurrence exhibit a contrast in detected RFI between Eastern and Western Hemispheres and between Northern and Southern Hemispheres. Peak-hold maps show both isolated and distributed regions of severe RFI, some of which correspond to populated areas and others to geographically isolated long-range radars. Maps of kurtosis-excess reveal much RFI likely due to terrestrial radar systems, although other analysis indicates proliferation of low-level non-radar sources. In one case of intense RFI there is no kurtosis-excess indicating noise-like behavior due to either the use advanced digital modulation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.637a2010K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.637a2010K"><span>Development of the RF Front-end of a Multi-Channel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> for Internal Body Temperature Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karabetsos, Sotiris; Koulouras, Grigorios; Charamis, Panagiotis; Adamidis, George; Vardiambasis, Ioannis O.; Nassiopoulos, Athanasios</p> <p>2015-09-01</p> <p><span class="hlt">Microwave</span> Thermograph (MT) is based on measuring the electromagnetic field spontaneously emitted by a body in <span class="hlt">micro-wave</span> frequency range. In <span class="hlt">microwave</span> <span class="hlt">radiometers</span>, temperature measurement is made by measuring the thermal noise power. The primary module that is used for detecting this thermal noise power is the RF Front-end, which must meet very challenging requirements in terms of accuracy for measuring the noise power at the input of the receiver. The work that will be presented here will exhibit the design approaches and specifications as well as the trade-offs and performance criteria towards the development and prototyping of the RF Front-end for a Multi-Channel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> for internal body temperature measurements in the l-4GHz frequency bands. The RF Front-end is intended to be integrated and be a part of a full <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> device that targets early detection of malignant tumours. The latter relate with the increase of temperature in cancerous cells and the precise detection of the temperature difference, which is the goal of the <span class="hlt">radiometer</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910021332','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910021332"><span>Rainfall estimation over oceans from scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> and special sensor <span class="hlt">microwave</span>/imager <span class="hlt">microwave</span> data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prabhakara, C.; Dalu, G.; Liberti, G. L.; Nucciarone, J. J.; Suhasini, R.</p> <p>1991-01-01</p> <p>The brightness temperature (T sub b) measured at 37 GHz shows fairly strong emission from rain, and only slight effects caused by scattering by ice above the rain clouds. At frequencies below 37 GHz, were the fov is larger and the volume extinction coefficient is weaker, it is found that the observations do not yield appreciable additional information about rain. At 85 GHz (fov = 15 km), where the volume extinction is considerably larger, direct information about rain below the clouds is usually masked. Based on the above ideas, 37 GHz observations with a 30 km fov from SMMR and SSM/I are selected to develop an empirical method for the estimation of rain rate. In this method, the statistics of the observed T sub b's at 37 GHz in a rain storm are related to the rain rate statistics in that storm. The underestimation of rain rate, arising from the inability of the <span class="hlt">radiometer</span> to respond sensitively to rain rate above a given threshold, is rectified in this technique with the aid of two parameters that depend on the total <span class="hlt">water</span> vapor content in the atmosphere. The retrieved rain rates compare favorably with radar observations and monthly mean global maps of rain derived from this technique over the oceans.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7670E..06S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7670E..06S"><span>Status of VESAS: a fully-electronic <span class="hlt">microwave</span> imaging <span class="hlt">radiometer</span> system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schreiber, Eric; Peichl, Markus; Suess, Helmut</p> <p>2010-04-01</p> <p>Present applications of <span class="hlt">microwave</span> remote sensing systems cover a large variety. One utilisation of the frequency range from 1 - 300 GHz is the domain of security and reconnaissance. Examples are the observation of critical infrastructures or the performance of security checks on people in order to detect concealed weapons or explosives, both being frequent threats in our world of growing international terrorism. The imaging capability of concealed objects is one of the main advantages of <span class="hlt">microwave</span> remote sensing, because of the penetration performance of electromagnetic waves through dielectric materials in this frequency domain. The main physical effects used in passive <span class="hlt">microwave</span> sensing rely on the naturally generated thermal radiation and the physical properties of matter, the latter being surface characteristics, chemical and physical composition, and the temperature of the material. As a consequence it is possible to discriminate objects having different material characteristics like ceramic weapons or plastic explosives with respect to the human body. Considering the use of <span class="hlt">microwave</span> imaging with respect to people scanning systems in airports, railway stations, or stadiums, it is advantageous that passively operating devices generate no exposure on the scanned objects like actively operating devices do. For frequently used security gateways it is additionally important to have a high through-put rate in order to minimize the queue time. Consequently fast imaging systems are necessary. In this regard the conceptual idea of a fully-electronic <span class="hlt">microwave</span> imaging <span class="hlt">radiometer</span> system is introduced. The two-dimensional scanning mechanism is divided into a frequency scan in one direction and the method of aperture synthesis in the other. The overall goal here is to design a low-cost, fully-electronic imaging system with a frame rate of around one second at Ka band. This frequency domain around a center frequency of 37 GHz offers a well-balanced compromise between the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950005966','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950005966"><span>Design studies of large aperture, high-resolution Earth science <span class="hlt">microwave</span> <span class="hlt">radiometers</span> compatible with small launch vehicles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schroeder, Lyle C.; Bailey, M. C.; Harrington, Richard F.; Kendall, Bruce M.; Campbell, Thomas G.</p> <p>1994-01-01</p> <p>High-spatial-resolution <span class="hlt">microwave</span> <span class="hlt">radiometer</span> sensing from space with reasonable swath widths and revisit times favors large aperture systems. However, with traditional precision antenna design, the size and weight requirements for such systems are in conflict with the need to emphasize small launch vehicles. This paper describes tradeoffs between the science requirements, basic operational parameters, and expected sensor performance for selected satellite <span class="hlt">radiometer</span> concepts utilizing novel lightweight compactly packaged real apertures. Antenna, feed, and <span class="hlt">radiometer</span> subsystem design and calibration are presented. Preliminary results show that novel lightweight real aperture coupled with state-of-the-art <span class="hlt">radiometer</span> designs are compatible with small launch systems, and hold promise for high-resolution earth science measurements of sea ice, precipitation, soil moisture, sea surface temperature, and ocean wind speeds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870017883','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870017883"><span>HMMR (High-Resolution Multifrequency <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span>) Earth observing system, volume 2e. Instrument panel report</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1987-01-01</p> <p>Recommendations and background are provided for a passive <span class="hlt">microwave</span> remote sensing system of the future designed to meet the observational needs of Earth scientist in the next decade. This system, called the High Resolution Multifrequency <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (HMMR), is to be part of a complement of instruments in polar orbit. Working together, these instruments will form an Earth Observing System (EOS) to provide the information needed to better understand the fundamental, global scale processes which govern the Earth's environment. Measurements are identified in detail which passive observations in the <span class="hlt">microwave</span> portion of the spectrum could contribute to an Earth Observing System in polar orbit. Requirements are established, e.g., spatial and temporal resolution, for these measurements so that, when combined with the other instruments in the Earth Observing System, they would yield a data set suitable for understanding the fundamental processes governing the Earth's environment. Existing and/or planned sensor systems are assessed in the light of these requirements, and additional sensor hardware needed to meet these observational requirements are defined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840011555&hterms=water+network&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwater%2Bnetwork','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840011555&hterms=water+network&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwater%2Bnetwork"><span>Inversion Algorithms for <span class="hlt">Water</span> Vapor <span class="hlt">Radiometers</span> Operating at 20.7 and 31.4 Ghz</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Resch, G. M.</p> <p>1984-01-01</p> <p>Eight <span class="hlt">water</span> vapor <span class="hlt">radiometers</span> (WVRs) were constructed as research and development tools to support the Advanced System Programs in the Deep Space Network and the Crustal Dynamics Project. These instruments are intended to operate at the stations of the Deep Space Network (DSN), various radio observatories, and obile facilities that participate in very long baseline interferometric (VLBI) experiments. It is expected that the WVRs will operate in a wide range of meteorological conditions. Several algorithms are discussed that are used to estimate the line-of-sight path delay due to <span class="hlt">water</span> vapor and columnar liquid <span class="hlt">water</span> rom the observed <span class="hlt">microwave</span> brightness temperatures provided by the WVRs. In particular, systematic effects due to site and seasonal variations are examined. The accuracy of the estimation as indicated by a simulation calculation is approximately 0.3 cm for a noiseless WVR in clear and moderately cloudy weather. With a realistic noise model of WVR behavior, the inversion accuracy is approximately 0.6 cm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840024608','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840024608"><span>The correction of aberrations computed in the aperture plane of multifrequency <span class="hlt">microwave</span> <span class="hlt">radiometer</span> antennas</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmidt, R. F.</p> <p>1984-01-01</p> <p>An analytical/numerical approach to identifying and correcting the aberrations introduced by a general displacement of the feed from the focal point of a single offset paraboloid antenna used in deployable <span class="hlt">radiometer</span> systems is developed. A 15 meter reflector with 18 meter focal length is assumed for the analysis, which considers far field radiation pattern quality, focal region fields, and aberrations appearing in the aperture plane. The latter are obtained by ray tracing in the transmit mode and are expressed in terms of optical notation. Attention is given to the physical restraints imposed on corrective elements by real <span class="hlt">microwave</span> systems and to the intermediate near field aspects of the problem in three dimensions. The subject of wave fronts and caustics in the receive mode is introduced for comparative purposes. Several specific examples are given for aberration reduction at eight beamwidths of scan at a frequency of 1.414 GHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920021492','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920021492"><span>A conceptual design of a large aperture <span class="hlt">microwave</span> <span class="hlt">radiometer</span> geostationary platform</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garn, Paul A.; Garrison, James L.; Jasinski, Rachel</p> <p>1992-01-01</p> <p>A conceptual design of a Large Aperture <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (LAMR) Platform has been developed and technology areas essential to the design and on-orbit viability of the platform have been defined. Those technologies that must be developed to the requirement stated here for the LAMR mission to be viable include: advanced radiation resistant solar cells, integrated complex structures, large segmented reflector panels, sub 3 kg/m(exp 2) areal density large antennas, and electric propulsion systems. Technology areas that require further development to enhance the capabilities of the LAMR platform (but are not essential for viability) include: electrical power storage, on-orbit assembly, and on-orbit systems checkout and correction.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930072111&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddmr','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930072111&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Ddmr"><span>Noncosmological signal contributions to the COBE DMR anisotropy maps. [Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bennett, C. L.; Hinshaw, G.; Banday, A.; Kogut, A.; Wright, E. L.; Loewenstein, K.; Cheng, E. S.</p> <p>1993-01-01</p> <p>We examine the COBE Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (DMR) data for evidence of noncosmological source contributions. The DMR maps are cross-correlated with maps of rich clusters, extragalactic IRAS sources, HEAO 1 A-2 X-ray emission, and 5 GHz radio sources. We limit the rms contributions from these sources on a 7 deg angular scale to less than 10 micro-K (95 percent confidence level) in the DMR maps, although the LMC probably contributes about 50 micro-K to a limited region of the sky. Thus, our previous interpretation that the fluctuations in the COBE DMR data are most likely due to cosmic fluctuations at the surface of last scattering remains intact. The Comptonization parameter for hot electrons traced by rich clusters is limited to delta(y) less than 2 x 10 exp -6 (95 percent confidence level) averaged over the 7 deg DMR beam.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830028789&hterms=appraisal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dappraisal','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830028789&hterms=appraisal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dappraisal"><span>Nimbus-7 scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> /SMMR/ in-orbit performance appraisal</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gloersen, P.; Cavalieri, D. J.; Gatlin, J. A.</p> <p>1981-01-01</p> <p>Calibration and processing techniques enacted during first year of operation of the Nimbus-7 scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (SMMR) are described. It was found that in-orbit calibration was necessary, as was fine-tuning of the geophysical parameter retrieval parameters to account for anomalies such as lower-than-expected polarization differences in ocean radiances. Phase shifts in the scan angles were corrected in order to avoid polarization mixing. Calibration constants to eliminate cross-talk and phase shift effects were established for radiation reflected from the earth, then averaged over data from 300 orbits to fit points on a sine curve to better than 0.2 K accuracy. An iterative approach was determined to be necessary due to signal anomalies caused by antenna dish oscillations. Global ocean and atmosphere parameters used to construct a radiation model of ten latitude bands are presented for use in radiation transfer equations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150020816','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150020816"><span>Aquarius L-Band <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span>: Three Years of Radiometric Performance and Systematic Effects</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Piepmeier, Jeffrey R.; Hong, Liang; Pellerano, Fernando A.</p> <p>2015-01-01</p> <p>The Aquarius L-band <span class="hlt">microwave</span> <span class="hlt">radiometer</span> is a three-beam pushbroom instrument designed to measure sea surface salinity. Results are analyzed for performance and systematic effects over three years of operation. The thermal control system maintains tight temperature stability promoting good gain stability. The gain spectrum exhibits expected orbital variations with 1f noise appearing at longer time periods. The on-board detection and integration scheme coupled with the calibration algorithm produce antenna temperatures with NEDT 0.16 K for 1.44-s samples. Nonlinearity is characterized before launch and the derived correction is verified with cold-sky calibration data. Finally, long-term drift is discovered in all channels with 1-K amplitude and 100-day time constant. Nonetheless, it is adeptly corrected using an exponential model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810013173','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810013173"><span>Topical cyclone rainfall characteristics as determined from a satellite passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rodgers, E. B.; Adler, R. F.</p> <p>1979-01-01</p> <p>Data from the Nimbus-5 Electrically Scanning <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (ESMR-5) were used to calculate latent heat release and other rainfall parameters for over 70 satellite observations of 21 tropical cyclones in the tropical North Pacific Ocean. The results indicate that the ESMR-5 measurements can be useful in determining the rainfall characteristics of these storms and appear to be potentially useful in monitoring as well as predicting their intensity. The ESMR-5 derived total tropical cyclone rainfall estimates agree favorably with previous estimates for both the disturbance and typhoon stages. The mean typhoon rainfall rate (1.9 mm h(-1)) is approximately twice that of disturbances (1.1 mm h(-1)).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810047736&hterms=forecasting+method&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dforecasting%2Bmethod','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810047736&hterms=forecasting+method&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dforecasting%2Bmethod"><span>An objective method for forecasting tropical cyclone intensity using Nimbus-5 electrically scanning <span class="hlt">microwave</span> <span class="hlt">radiometer</span> measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hunter, H. E.; Rodgers, E. B.; Shenk, W. E.</p> <p>1981-01-01</p> <p>An empirical analysis program, based on finding an optimal representation of the data, is applied to 120 observations of 29 1973 and 1974 North Pacific tropical cyclones. It is found that the algorithms developed from the Nimbus-5 Electrically Scanning <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (ESMR-5) base alone outperformed the Joint Typhoon Warning Center (JTWC) operational forecast for the 48 and 72 hour maximum wind speed. It is also found that the ESMR-5 data base, when combined with the non-satellite base, produced algorithms that improved the 24 and 48 hour maximum wind-speed forecast by as much as 10% and the 72 hour maximum wind forecast by approximately 16% as compared to the forecast obtained from the algorithms developed from the non-satellite data base alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830033643&hterms=geyser&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgeyser','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830033643&hterms=geyser&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dgeyser"><span>Observations of oceanic surface-wind fields from the Nimbus-7 <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miller, J. R.; Geyser, J. E.; Chang, A. T. C.; Wilheit, T. T., Jr.</p> <p>1982-01-01</p> <p>Brightness temperatures from the five-frequency dual-polarized scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (SMMR) on Nimbus 7 have been used to obtain surface wind fields over the ocean. The satellite-derived wind field for 1200Z, Feb. 19, 1979, in the eastern North Pacific has been compared with an operationally generated surface-wind analysis field. Previous point comparisons at selected locations have indicated that satellite winds are accurate to 3 m/sec. The results, although of a preliminary nature, indicate that SMMR-derived winds may be used to determine large-scale wind fields over the ocean, particularly in areas of strong wind gradients such as found in cyclonic systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780025703','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780025703"><span>Geosynchronous <span class="hlt">Microwave</span> Atmospheric Sounding <span class="hlt">Radiometer</span> (MASR) antenna feasibility study. Volume 3: Antenna feasibility</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Villeneuve, A. T.</p> <p>1978-01-01</p> <p>Antenna systems capable of operating with a multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> intended for mapping severe storm activity over patches on the surface of the earth 750 km square were compared. These systems included a paraboloidal reflector with an offset focal point feed, and a symmetrical Cassegrain reflector system. Both systems are acceptable from the point of view of beam efficiency, however, from the point of view of maintaining the required positional accuracies and surface tolerances, as well as from the point of view of manufacturability, cost effectiveness, and technical risk, the symmetrical Casegrain was selected as the preferred configuration. Performance characteristics were calculated and a mechanical design study was conducted to provide estimates of the technical risk, costs, and development time required for the construction of such an antenna system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EPJWC.11915005A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EPJWC.11915005A"><span>Exploring the Turbulent Urban Boundary by Use of Lidars and <span class="hlt">Microwave</span> <span class="hlt">Radiometers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arend, Mark; Valerio, Ivan; Neufeld, Stephen; Bishir, Raymond; Wu, Younghu; Moshary, Fred; Melecio-Vazquez, David; Gonzalez, Jorge</p> <p>2016-06-01</p> <p>A Doppler lidar has been developed using fiber optic based technologies and advanced signal processing techniques. Although this system has been operated in a scanning mode in the past, for this application, the system is operated in a vertically pointing mode and delivers a time series of vertical velocity profiles. By cooperating the Doppler lidar with other instruments, including a back scatter lidar, and a <span class="hlt">microwave</span> <span class="hlt">radiometer</span>, models of atmospheric stability can be tested, opening up an exciting path for researchers, applied scientists and engineers to discover unique phenomena related to fundamental atmospheric science processes. A consistent set of retrievals between each of these instruments emphasizes the utility for such a network of instruments to better characterize the turbulent atmospheric urban boundary layers which is expected to offer a useful capability for assessing and improving models that are in great need of such ground truth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920052427&hterms=salinity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dsalinity','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920052427&hterms=salinity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dsalinity"><span>A synthetic aperture <span class="hlt">microwave</span> <span class="hlt">radiometer</span> to measure soil moisture and ocean salinity from space</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Le Vine, D. M.; Hilliard, L. M.; Swift, C. T.; Ruf, C. S.; Garrett, L. B.</p> <p>1991-01-01</p> <p>A concept is presented for a <span class="hlt">microwave</span> <span class="hlt">radiometer</span> in space to measure soil moisture and ocean salinity as part of an 'Earth Probe' mission. The measurements could be made using an array of stick antennas. The L-band channel (1.4 GHz) would be the primary channel for determining soil moisture, with the S-band (2.65-GHz) and C-band (5.0-GHz) channels providing ancillary information to help correct for the effects of the vegetation canopy and possibly to estimate a moisture profile. A preliminary study indicates that an orbit at 450 km would provide coverage of better than 95 percent of the earth every 3 days. A 10-km resolution cell (at nadir) requires stick antennas about 9.5-m long at L-band. The S-band and C-band sticks would be substantially shorter (5 m and 2.7 m, respectively).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820018649','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820018649"><span>The Effect of Sea-Surface Sun Glitter on <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wentz, F. J.</p> <p>1981-01-01</p> <p>A relatively simple model for the <span class="hlt">microwave</span> brightness temperature of sea surface Sun glitter is presented. The model is an accurate closeform approximation for the fourfold Sun glitter integral. The model computations indicate that Sun glitter contamination of on orbit <span class="hlt">radiometer</span> measurements is appreciable over a large swath area. For winds near 20 m/s, Sun glitter affects the retrieval of environmental parameters for Sun angles as large as 20 to 25 deg. The model predicted biases in retrieved wind speed and sea surface temperature due to neglecting Sun glitter are consistent with those experimentally observed in SEASAT SMMR retrievals. A least squares retrieval algorithm that uses a combined sea and Sun model function shows the potential of retrieving accurate environmental parameters in the presence of Sun glitter so long as the Sun angles and wind speed are above 5 deg and 2 m/s, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010110401&hterms=Discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DDiscrimination','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010110401&hterms=Discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DDiscrimination"><span>TRMM <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Rain Rate Estimation Method with Convective and Stratiform Discrimination</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prabhakara, Cuddapah; Iacovazzi, R.; Weinman, J. A.; Dalu, G.; Einaudi, Franco (Technical Monitor)</p> <p>2000-01-01</p> <p>Tropical Rainfall Measuring Mission (TRMM) <span class="hlt">Microwave</span> Imager (TMI) <span class="hlt">radiometer</span> brightness temperature data in the 85 GHz channel (T85) reveal distinct local minima (T85min) in a regional map containing a Mesoscale Convective System (MCS). A map of surface rain rate for that region, deduced from simultaneous measurements made by the Precipitation Radar (PR) on board the TRMM satellite, reveals that these T85min, produced by scattering, correspond to local PR rain maxima. Utilizing the PR rain rate map as a guide, we have developed a TMI algorithm to retrieve convective and stratiform rain. In this algorithm, two parameters are used to classify three kinds of thunderstorms (Cbs) based on the T85 data: a) the magnitude of scattering depression deduced from local T85mi, and b) the mean horizontal gradient of T85 around such minima. Initially, the algorithm is optimized or tuned utilizing the PR and TMI data of a few MCS events. The areal distribution of light (1-10 mm/hr), moderate (10-20 mm/hr), and intense (greater than or equal to 20 mm/hr) rain rates are retrieved on the average with an accuracy of about 15%. Taking advantage of this ability of our retrieval method, one could derive the latent heat input into the atmosphere over the 760 km wide swath of the TMI <span class="hlt">radiometer</span> in the tropics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090001840&hterms=rain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Drain','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090001840&hterms=rain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Drain"><span>Wind Retrievals under Rain for Passive Satellite <span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> and its Applications to Hurricane Tracking</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Meissner, Thomas; Wentz, Frank J.</p> <p>2008-01-01</p> <p>We have developed an algorithm that retrieves wind speed under rain using C-hand and X-band channels of passive <span class="hlt">microwave</span> satellite <span class="hlt">radiometers</span>. The spectral difference of the brightness temperature signals due to wind or rain allows to find channel combinations that are sufficiently sensitive to wind speed but little or not sensitive to rain. We &ve trained a statistical algorithm that applies under hurricane conditions and is able to measure wind speeds in hurricanes to an estimated accuracy of about 2 m/s. We have also developed a global algorithm, that is less accurate but can be applied under all conditions. Its estimated accuracy is between 2 and 5 mls, depending on wind speed and rain rate. We also extend the wind speed region in our model for the wind induced sea surface emissivity from currently 20 m/s to 40 mls. The data indicate that the signal starts to saturate above 30 mls. Finally, we make an assessment of the performance of wind direction retrievals from polarimetric <span class="hlt">radiometers</span> as function of wind speed and rain rate</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020023454','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020023454"><span>Global Climate Monitoring with the EOS PM-Platform's Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> (AMSR-E)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spencer, Roy W.</p> <p>2002-01-01</p> <p>The Advanced <span class="hlt">Microwave</span> Scanning 2 <span class="hlt">Radiometer</span> (AMSR-E) is being built by NASDA to fly on NASA's PM Platform (now called Aqua) in December 2000. This is in addition to a copy of AMSR that will be launched on Japan's ADEOS-II satellite in 2001. The AMSRs improve upon the window frequency <span class="hlt">radiometer</span> heritage of the SSM/I and SMMR instruments. Major improvements over those instruments include channels spanning the 6.9 GHz to 89 GHz frequency range, and higher spatial resolution from a 1.6 m reflector (AMSR-E) and 2.0 m reflector (ADEOS-II AMSR). The ADEOS-II AMSR also will have 50.3 and 52.8 GHz channels, providing sensitivity to lower tropospheric temperature. NASA funds an AMSR-E Science Team to provide algorithms for the routine production of a number of standard geophysical products. These products will be generated by the AMSR-E Science Investigator-led Processing System (SIPS) at the Global Hydrology Resource Center (GHRC) in Huntsville, Alabama. While there is a separate NASDA-sponsored activity to develop algorithms and produce products from AMSR, as well as a Joint (NASDA-NASA) AMSR Science Team 3 activity, here I will review only the AMSR-E Team's algorithms and how they benefit from the new capabilities that AMSR-E will provide. The US Team's products will be archived at the National Snow and Ice Data Center (NSIDC).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010110401&hterms=discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddiscrimination','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010110401&hterms=discrimination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddiscrimination"><span>TRMM <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Rain Rate Estimation Method with Convective and Stratiform Discrimination</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prabhakara, Cuddapah; Iacovazzi, R.; Weinman, J. A.; Dalu, G.; Einaudi, Franco (Technical Monitor)</p> <p>2000-01-01</p> <p>Tropical Rainfall Measuring Mission (TRMM) <span class="hlt">Microwave</span> Imager (TMI) <span class="hlt">radiometer</span> brightness temperature data in the 85 GHz channel (T85) reveal distinct local minima (T85min) in a regional map containing a Mesoscale Convective System (MCS). A map of surface rain rate for that region, deduced from simultaneous measurements made by the Precipitation Radar (PR) on board the TRMM satellite, reveals that these T85min, produced by scattering, correspond to local PR rain maxima. Utilizing the PR rain rate map as a guide, we have developed a TMI algorithm to retrieve convective and stratiform rain. In this algorithm, two parameters are used to classify three kinds of thunderstorms (Cbs) based on the T85 data: a) the magnitude of scattering depression deduced from local T85mi, and b) the mean horizontal gradient of T85 around such minima. Initially, the algorithm is optimized or tuned utilizing the PR and TMI data of a few MCS events. The areal distribution of light (1-10 mm/hr), moderate (10-20 mm/hr), and intense (greater than or equal to 20 mm/hr) rain rates are retrieved on the average with an accuracy of about 15%. Taking advantage of this ability of our retrieval method, one could derive the latent heat input into the atmosphere over the 760 km wide swath of the TMI <span class="hlt">radiometer</span> in the tropics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999JApMe..38..633O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999JApMe..38..633O"><span>Atmospheric Latent Heating Distributions in the Tropics Derived from Satellite Passive <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Measurements.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olson, William S.; Kummerow, Christian D.; Hong, Ye; Tao, Wei-Kuo</p> <p>1999-06-01</p> <p>A method for the remote sensing of three-dimensional latent heating distributions in precipitating tropical weather systems from satellite passive <span class="hlt">microwave</span> observations is presented. In this method, cloud model simulated hydrometeor/latent heating vertical profiles that have radiative characteristics consistent with a given set of multispectral <span class="hlt">microwave</span> radiometric observations are composited to create a best estimate of the observed profile. An estimate of the areal coverage of convective precipitation within the <span class="hlt">radiometer</span> footprint is used as an additional constraint on the contributing model profiles. This constraint leads to more definitive retrieved profiles of precipitation and latent heating in synthetic data tests.The remote sensing method is applied to Special Sensor <span class="hlt">Microwave</span>/Imager (SSM/I) observations of tropical systems that occurred during the TOGA COARE Intensive Observing Period, and to observations of Hurricane Andrew (1992). Although instantaneous estimates of rain rates are high-biased with respect to coincident radar rain estimates, precipitation patterns are reasonably correlated with radar patterns, and composite rain rate and latent heating profiles show respectable agreement with estimates from forecast models and heat and moisture budget calculations. Uncertainties in the remote sensing estimates of precipitation/latent heating may be partly attributed to the relatively low spatial resolution of the SSM/I and a lack of <span class="hlt">microwave</span> sensitivity to tenuous anvil cloud, for which upper-tropospheric latent heating rates may be significant. Estimated latent heating distributions in Hurricane Andrew exhibit an upper-level heating maximum that strengthens as the storm undergoes a period of intensification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000037974&hterms=precipitation+index&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprecipitation%2Bindex','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000037974&hterms=precipitation+index&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprecipitation%2Bindex"><span>Global Oceanic Precipitation: A Joint View by TOPEX and the TOPEX <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, Ge; Chapron, Bertrand; Tournadre, Jean; Katsaros, Kristina; Vandemark, Douglas</p> <p>1997-01-01</p> <p>The TOPEX/POSEIDON mission offers the first opportunity to observe rain cells over the ocean by a dual-frequency radar altimeter (TOPEX) and simultaneously observe their natural radiative properties by a three-frequency <span class="hlt">radiometer</span> (TOPEX <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (TMR)). This work is a feasibility study aimed at understanding the capability and potential of the active/passive TOPEX/TMR system for oceanic rainfall detection. On the basis of past experiences in rain flagging, a joint TOPEX/TMR rain probability index is proposed. This index integrates several advantages of the two sensors and provides a more reliable rain estimate than the <span class="hlt">radiometer</span> alone. One year's TOPEX/TMR data are used to test the performance of the index. The resulting rain frequency statistics show quantitative agreement with those obtained from the Comprehensive Ocean-Atmosphere Data Set (COADS) in the Intertropical Convergence Zone (ITCZ), while qualitative agreement is found for other regions of the world ocean. A recent finding that the latitudinal frequency of precipitation over the Southern Ocean increases steadily toward the Antarctic continent is confirmed by our result. Annual and seasonal precipitation maps are derived from the index. Notable features revealed include an overall similarity in rainfall pattern from the Pacific, the Atlantic, and the Indian Oceans and a general phase reversal between the two hemispheres, as well as a number of regional anomalies in terms of rain intensity. Comparisons with simultaneous Global Precipitation Climatology Project (GPCP) multisatellite precipitation rate and COADS rain climatology suggest that systematic differences also exist. One example is that the maximum rainfall in the ITCZ of the Indian Ocean appears to be more intensive and concentrated in our result compared to that of the GPCP. Another example is that the annual precipitation produced by TOPEX/TMR is constantly higher than those from GPCP and COADS in the extratropical regions of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000037974&hterms=World+migration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DWorld%2Bmigration','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000037974&hterms=World+migration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DWorld%2Bmigration"><span>Global Oceanic Precipitation: A Joint View by TOPEX and the TOPEX <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, Ge; Chapron, Bertrand; Tournadre, Jean; Katsaros, Kristina; Vandemark, Douglas</p> <p>1997-01-01</p> <p>The TOPEX/POSEIDON mission offers the first opportunity to observe rain cells over the ocean by a dual-frequency radar altimeter (TOPEX) and simultaneously observe their natural radiative properties by a three-frequency <span class="hlt">radiometer</span> (TOPEX <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (TMR)). This work is a feasibility study aimed at understanding the capability and potential of the active/passive TOPEX/TMR system for oceanic rainfall detection. On the basis of past experiences in rain flagging, a joint TOPEX/TMR rain probability index is proposed. This index integrates several advantages of the two sensors and provides a more reliable rain estimate than the <span class="hlt">radiometer</span> alone. One year's TOPEX/TMR data are used to test the performance of the index. The resulting rain frequency statistics show quantitative agreement with those obtained from the Comprehensive Ocean-Atmosphere Data Set (COADS) in the Intertropical Convergence Zone (ITCZ), while qualitative agreement is found for other regions of the world ocean. A recent finding that the latitudinal frequency of precipitation over the Southern Ocean increases steadily toward the Antarctic continent is confirmed by our result. Annual and seasonal precipitation maps are derived from the index. Notable features revealed include an overall similarity in rainfall pattern from the Pacific, the Atlantic, and the Indian Oceans and a general phase reversal between the two hemispheres, as well as a number of regional anomalies in terms of rain intensity. Comparisons with simultaneous Global Precipitation Climatology Project (GPCP) multisatellite precipitation rate and COADS rain climatology suggest that systematic differences also exist. One example is that the maximum rainfall in the ITCZ of the Indian Ocean appears to be more intensive and concentrated in our result compared to that of the GPCP. Another example is that the annual precipitation produced by TOPEX/TMR is constantly higher than those from GPCP and COADS in the extratropical regions of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800020136','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800020136"><span>The development of a stepped frequency <span class="hlt">microwave</span> <span class="hlt">radiometer</span> and its application to remote sensing of the Earth</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Harrington, R. F.</p> <p>1980-01-01</p> <p>The design, development, application, and capabilities of a variable frequency <span class="hlt">microwave</span> <span class="hlt">radiometer</span> are described. This <span class="hlt">radiometer</span> demonstrated the versatility, accuracy, and stability required to provide contributions to the geophysical understanding of ocean and ice processes. A closed-loop feedback method was used, whereby noise pulses were added to the received electromagnetic radiation to achieve a null balance in a Dicke switched <span class="hlt">radiometer</span>. Stability was achieved through the use of a constant temperature enclosure around the low loss <span class="hlt">microwave</span> front end. The Dicke reference temperature was maintained to an absolute accuracy of 0.1 K using a closed-loop proportional temperature controller. A microprocessor based digital controller operates the <span class="hlt">radiometer</span> and records the data on computer compatible tapes. This <span class="hlt">radiometer</span> exhibits an absolute accuracy of better than 0.5 K when the sensitivity is 0.1 K. The sensitivity varies between 0.0125 K and 1.25 K depending upon the bandwidth and integration time selected by the digital controller. Remote sensing experiments were conducted from an aircraft platform and the first radiometeric mapping of an ocean polar front; exploratory experiments to measure the thickness of lake ice; first discrimination between first year and multiyear ice below 10 GHz; and the first known measurements of frequency sensitive characteristics of sea ice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994ApJ...437....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994ApJ...437....1S"><span>Statistics and topology of the COBE differential <span class="hlt">microwave</span> <span class="hlt">radiometer</span> first-year sky maps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smoot, G. F.; Tenorio, L.; Banday, A. J.; Kogut, A.; Wright, E. L.; Hinshaw, G.; Bennett, C. L.</p> <p>1994-12-01</p> <p>We use statistical and topological quantities to test the Cosmic Background Explorer (COBE) Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (DMR) first-year sky maps against the hypothesis that the observed temperature fluctuations reflect Gaussian initial density perturbations with random phases. Recent papers discuss specific quantities as discriminators between Gaussian and non-Gaussian behavior, but the treatment of instrumental noise on the data is largely ignored. The presence of noise in the data biases many statistical quantities in a manner dependent on both the noise properties and the unknown cosmic <span class="hlt">microwave</span> background temperature field. Appropriate weighting schemes can minimize this effect, but it cannot be completely eliminated. Analytic expressions are presented for these biases, and Monte Carlo simulations are used to assess the best strategy for determining cosmologically interesting information from noisy data. The genus is a robust discriminator that can be used to estimate the power-law quadrupole-normalized amplitude, Qrms-PS, independently of the two-point correlation function. The genus of the DMR data is consistent with Gaussian initial fluctuations with Qrms-PS = (15.7 +/- 2.2) - (6.6 +/- 0.3)(n - 1) micro-K, where n is the power-law index. Fitting the rms temperature variations at various smoothing angles gives Qrms-PS = 13.2 +/- 2.5 micro-K and n = 1.7(+0.3(-0.6)). While consistent with Gaussian fluctuations, the first year data are only sufficient to rule out strongly non-Gaussian distributions of fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000038136&hterms=ieee&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dieee','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000038136&hterms=ieee&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dieee"><span>Passive <span class="hlt">Microwave</span> Observation of Soil <span class="hlt">Water</span> Infiltration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jackson, Thomas J.; Schmugge, Thomas J.; Rawls, Walter J.; ONeill, Peggy E.; Parlange, Marc B.</p> <p>1997-01-01</p> <p>Infiltration is a time varying process of <span class="hlt">water</span> entry into soil. Experiments were conducted here using truck based <span class="hlt">microwave</span> <span class="hlt">radiometers</span> to observe small plots during and following sprinkler irrigation. Experiments were conducted on a sandy loam soil in 1994 and a silt loam in 1995. Sandy loam soils typically have higher infiltration capabilities than clays. For the sandy loam the observed brightness temperature (TB) quickly reached a nominally constant value during irrigation. When the irrigation was stopped the TB began to increase as drainage took place. The irrigation rates in 1995 with the silt loam soil exceeded the saturated conductivity of the soil. During irrigation the TB values exhibited a pattern that suggests the occurrence of coherent reflection, a rarely observed phenomena under natural conditions. These results suggested the existence of a sharp dielectric boundary (wet over dry soil) that was increasing in depth with time.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.C21A0564S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.C21A0564S"><span>Snow stratigraphic heterogeneity within ground-based passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> footprints: implications for emission modelling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sandells, M.; Rutter, N.; Derksen, C.; Langlois, A.; Lemmetyinen, J.; Montpetit, B.; Pulliainen, J. T.; Royer, A.; Toose, P.</p> <p>2012-12-01</p> <p>Remote sensing of snow mass remains a challenging area of research. Scattering of electromagnetic radiation is sensitive to snow mass, but is also affected by contrasts in the dielectric properties of the snow. Although the argument that errors from simple algorithms average out at large scales has been used to justify current retrieval methods, it is not obvious why this should be the case. This hypothesis needs to be tested more rigorously. A ground-based field experiment was carried out to assess the impact of sub-footprint snow heterogeneity on <span class="hlt">microwave</span> brightness temperature, in Churchill, Canada in winter in early 2010. Passive <span class="hlt">microwave</span> measurements of snow were made using sled-mounted <span class="hlt">radiometers</span> at 75cm intervals over a 5m transect. Measurements were made at horizontal and vertical polarizations at frequencies of 19 and 37 GHz. Snow beneath the <span class="hlt">radiometer</span> footprints was subsequently excavated, creating a snow trench wall along the centrepoints of adjacent footprints. The trench wall was carefully smoothed and photographed with a near-infrared camera in order to determine the positions of stratigraphic snow layer boundaries. Three one-dimensional vertical profiles of snowpack properties (density and snow specific surface area) were taken at 75cm, 185cm and 355cm from the left hand side of the trench. These profile measurements were used to derive snow density and grain size for each of the layers identified from the NIR image. <span class="hlt">Microwave</span> brightness temperatures for the 2-dimensional map of snow properties was simulated with the Helsinki University of Technology (HUT) model at 1cm intervals horizontally across the trench. Where each of five ice lenses was identified in the snow stratigraphy, a decrease in brightness temperature was simulated. However, the median brightness temperature simulated across the trench was substantially higher than the observations, of the order of tens of Kelvin, dependent on frequency and polarization. In order to understand and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140007380','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140007380"><span><span class="hlt">Microwave</span> Properties of Ice-Phase Hydrometeors for Radar and <span class="hlt">Radiometers</span>: Sensitivity to Model Assumptions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Johnson, Benjamin T.; Petty, Grant W.; Skofronick-Jackson, Gail</p> <p>2012-01-01</p> <p>A simplied framework is presented for assessing the qualitative sensitivities of computed <span class="hlt">microwave</span> properties, satellite brightness temperatures, and radar reflectivities to assumptions concerning the physical properties of ice-phase hydrometeors. Properties considered included the shape parameter of a gamma size distribution andthe melted-equivalent mass median diameter D0, the particle density, dielectric mixing formula, and the choice of complex index of refraction for ice. We examine these properties at selected <span class="hlt">radiometer</span> frequencies of 18.7, 36.5, 89.0, and 150.0 GHz; and radar frequencies at 2.8, 13.4, 35.6, and 94.0 GHz consistent with existing and planned remote sensing instruments. Passive and active <span class="hlt">microwave</span> observables of ice particles arefound to be extremely sensitive to the melted-equivalent mass median diameter D0 ofthe size distribution. Similar large sensitivities are found for variations in the ice vol-ume fraction whenever the geometric mass median diameter exceeds approximately 1/8th of the wavelength. At 94 GHz the two-way path integrated attenuation is potentially large for dense compact particles. The distribution parameter mu has a relatively weak effect on any observable: less than 1-2 K in brightness temperature and up to 2.7 dB difference in the effective radar reflectivity. Reversal of the roles of ice and air in the MaxwellGarnett dielectric mixing formula leads to a signicant change in both <span class="hlt">microwave</span> brightness temperature (10 K) and radar reflectivity (2 dB). The choice of Warren (1984) or Warren and Brandt (2008) for the complex index of refraction of ice can produce a 3%-4% change in the brightness temperature depression.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000014066','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000014066"><span>Global Climate Monitoring with the Eos Pm-Platform's Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> (AMSR-E)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spencer, Roy W.</p> <p>2000-01-01</p> <p>The Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> (AMSR-E) is being built by NASDA to fly on NASA's PM Platform (now called "Aqua") in December 2000. This is in addition to a copy of AMSR that will be launched on Japan's ADEOS-11 satellite in 2001. The AMSRs improve upon the window frequency <span class="hlt">radiometer</span> heritage of the SSM[l and SMMR instruments. Major improvements over those instruments include channels spanning the 6.9 GHz to 89 GHz frequency range, and higher spatial resolution from a 1.6 m reflector (AMSR-E) and 2.0 m reflector (ADEOS-11 AMSR). The ADEOS-11 AMSR also will have 50.3 and 52.8 GHz channels, providing sensitivity to lower tropospheric temperature. NASA funds an AMSR-E Science Team to provide algorithms for the routine production of a number of standard geophysical products. These products will be generated by the AMSR-E Science Investigator-led Processing System (SIPS) at the Global Hydrology Resource Center (GHRC) in Huntsville, Alabama. While there is a separate NASDA-sponsored activity to develop algorithms and produce products from AMSR, as well as a Joint (NASDA-NASA) AMSR Science Team activity, here I will review only the AMSR-E Team's algorithms and how they benefit from the new capabilities that AMSR-E will provide. The U.S. Team's products will be archived at the National Snow and Ice Data Center (NSIDC). Further information about AMSR-E can be obtained at http://www.jzhcc.msfc.nasa.Vov/AMSR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017sgvi.confE..22K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017sgvi.confE..22K"><span>Quantitative Characterisation of Sky Conditions on Paranal with the <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> LHATPRO – Five Years and Learning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kerber, Florian; Querel, R.; Neureiter, B.; Hanuschik, R.</p> <p>2017-09-01</p> <p>"A Low Humidity and Temperature Profiling (LHATPRO) <span class="hlt">microwave</span> <span class="hlt">radiometer</span>, optimized for measuring small amounts of atmospheric precipitable <span class="hlt">water</span> vapour (PWV), has now been in use for more than five years to monitor sky conditions over ESO's Paranal observatory (median PWV 2.5 mm). We'll summarise the performance characteristics of the unit and the current applications of its data in scheduling observations in Service Mode to take advantage of favourable conditions for infrared observations. We'll elaborate on our improved understanding of PWV over Paranal, including an analysis of PWV homogeneity addressing an important calibration issue. In addition we'll describe how the capabilities of the LHATPRO can be used in the future to further strengthen science operations and calibration by also offering line-of-sight support for individual VLT observations. Using its IR data we developed a method for an automated classification of photometric observing conditions in a quantitative way, supporting high precision photometry. Its highly precise PWV measurements enable new low PWV science during episodes of extremely low <span class="hlt">water</span> vapour that result in a strongly increased transmission also outside the standard atmospheric windows. A goal for the future is to combine various diagnostics measurements (altitude resolved profiles) by LHATPRO and other instruments and sophisticated atmospheric modeling to better characterize relevant properties of the atmosphere and to thus enable more precise, local short-term forecasting for optimised science operations."</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920044220&hterms=parts+rocket&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dparts%2Brocket','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920044220&hterms=parts+rocket&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dparts%2Brocket"><span>Tropical Rainfall Measuring Mission (TRMM) project. VI - Spacecraft, scientific instruments, and launching rocket. Part 3 - The electrically Scanning <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> and the Special Sensor <span class="hlt">Microwave</span>/Imager</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilheit, Thomas T.; Yamasaki, Hiromichi</p> <p>1990-01-01</p> <p>The two <span class="hlt">microwave</span> <span class="hlt">radiometers</span> for TRMM are designed to measure thermal <span class="hlt">microwave</span> radiation upwelling from the earth. The Electrically Scanning <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (ESMR) scans from 50 deg to the left through nadir to 50 deg to the right in 78 steps with no moving mechanical parts in a band centered at 19.35 GHz. The TRMM concept uses the radar to develop a climatology of rain-layer thickness which can be used for the interpretation of the <span class="hlt">radiometer</span> data over a swath wider than the radar. The ESMR data are useful for estimating rain intensity only over an ocean background. The Special Sensor <span class="hlt">Microwave</span>/Imager (SSM/I), which scans conically with three dual polarized channels at 19, 37, and 85 GHz and a single polarized channel at 22 GHz, provides a wider range of rainfall intensities. The SSM/I spins about an axis parallel to the local spacecraft vector and 128 uniformly spaced samples of the 85 GHz data are taken on each scan over a 112-deg scan region simultaneously with 64 samples of the other frequencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.4168M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.4168M"><span>The Capability of <span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> In Retrieving Soil Moisture Profiles Using A Neural Networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Macelloni, G.; Paloscia, S.; Santi, E.; Tedesco, M.</p> <p></p> <p>Hydrological models require the knowledge of land surface parameters like soil mois- ture and snow properties with a large spatial distribution and high temporal frequency. Whilst conventional methods are unable to satisfy the constraints of space and time estimation of these parameters, the use of remote sensing data represents a real im- provement. In particular the potential of data collected by <span class="hlt">microwave</span> <span class="hlt">radiometers</span> at low frequencies to extract soil moisture has been clearly demonstrated in several pa- pers. However, the penetration power into the soil depends on frequency and, whereas L-band is able to estimate the moisture of a relatively thick soil layer, higher frequen- cies are only sensitive to the moisture of soil layer closer to the surface. This remark leads to the hypothesis that multifrequency observations could be able to retrieve a soil moisture profile. In several experiments carried out both on agricultural fields and on samples of soil in a tank, by using the IROE multifrequency <span class="hlt">microwave</span> <span class="hlt">radiometers</span>, the effect of moisture and surface roughness on different frequencies was studied. From this experiments the capability of L-band in measuring the moisture of a soil layer of several centimeters, in the order of the wavelength, was confirmed, as well the sensitivity to the moisture of the first centimeters layer at C- and X-bands, and the one of the very first layer of smooth soil at Ka-band. Using an electromagnetic model (Integral Equation Model, IEM) the brightness temperatures as a function of the in- cidence angle were computed at 1.4, 6, 10, and 37 GHz for different soil moisture profiles and different surface roughness. A particular consideration was dedicated to the latter parameter, since, especially at Ka band, surface roughness strongly affects the emission and masks the effect of moisture. Different soil moisture profiles have been tested: increasing and decreasing with depth and also constant for sandy and sandy-loam soils. After this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4821504H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4821504H"><span>Rock infromation of the moon revealed by multi-channel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Guo-Ping; Zheng, Yong-Chun; Chan, Kwing Lam; Xu, Ao-Ao; This work is supported by Science and Technology Development Fund in Macao SAR 048/2012/A2 and 039/2013/A2, and the NSFC program (41490633). The CE data was supported by the Key Laboratory of Lunar and Deep Space Exploration (2013DP173157), National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China.</p> <p>2016-10-01</p> <p>Rock abundance on lunar surface is an important consideration for understanding the physical properties of the Moon. With the deeper penetration power of the <span class="hlt">microwave</span>, data from Chang'E (CE) multichannel (3.0-, 7.8-, 19.35-, and 37-GHz) <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (MRM) are used to constrain the rock distribution on the Moon. The contrasting thermo-physical properties between rocks and regolith fines cause multiple brightness temperature (TB) to be present within the field of view of CE <span class="hlt">microwave</span> data. But these variations could be easily masked by the more significant effect of ilmenite on TB, especially in the mare regions which are rich in ilmenite.To highlight the rock effect in TB, the diurnal TB difference, which has the effect of enlarging the TB difference caused by the rock abundance and reducing the absolute error of the CE <span class="hlt">microwave</span> data, is considered here. The rock information in TB data is distinguished from the ilmenite effect by comparing the diurnal TB difference with a statistical TB model of the mare regions which are relatively low in rock abundance. The employed statistical TB model is a polynomial fitting formula between the selected CE TB data from mare regions and the corresponding TiO2 content data from Clementine UVVIS data. The correlation coefficients of the polynomial fit between TB and TiO2 content are 0.94 at lunar daytime and 0.84 at lunar nighttime, respectively. This polynomial fit forms an approximated relationship between the TiO2 content and TB when rock abundance is zero, with a standard error determined from the regression procedure.Based on the TiO2 map retrieved from Clementine UVVIS data, the TB map that is deflated to a lower TiO2 content shows a distribution trend similar to the rock abundance map retrieved by LRO data, except for the mare regions at the nearside of the Moon. The bigger diurnal TB difference in the mare regions could be either caused by the rich ilmenite rocks or the smaller rocks which cannot be recognized by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860048846&hterms=microwave+imaging&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmicrowave%2Bimaging','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860048846&hterms=microwave+imaging&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmicrowave%2Bimaging"><span><span class="hlt">Microwave</span> backscatter and emission observed from Shuttle Imaging Radar B and an airborne 1.4 GHz <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, J. R.; Schiue, J. C.; Schmugge, T. J.; Engman, E. T.; Mo, T.; Lawrence, R. W.</p> <p>1985-01-01</p> <p>A soil moisture experiment conducted with the Shuttle Imaging Radar B (SIR-B) is reported. SIR-B operated at 1.28 GHz provided the active <span class="hlt">microwave</span> measurements, while a 4-beam pushbroom 1.4 GHz <span class="hlt">radiometer</span> gave the complementary passive <span class="hlt">microwave</span> measurements. The aircraft measurements were made at an altitude of 330 m, resulting in a ground resolution cell of about 100 m diameter. SIR-B ground resolution from 225 km was about 35 m. More than 150 agricultural fields in the San Joaquin Valley of California were examined in the experiment. The effect of surface roughness height on radar backscatter and radiometric measurements was studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994WRR....30.1321S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994WRR....30.1321S"><span>Push broom <span class="hlt">microwave</span> <span class="hlt">radiometer</span> observations of surface soil moisture in Monsoon '90</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmugge, T.; Jackson, T. J.; Kustas, W. P.; Roberts, R.; Parry, R.; Goodrich, D. C.; Amer, S. A.; Weltz, M. A.</p> <p>1994-05-01</p> <p>The push broom <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (PBMR) was flown on six flights of the NASA C-130 to map the surface soil moisture over the U.S. Department of Agriculture's Agricultural Research Service Walnut Gulch experimental watershed in southeastern Arizona. The PBMR operates at a wavelength of 21 cm and has four horizontally polarized beams which cover a swath of 1.2 times the aircraft altitude. By flying a series of parallel flight lines it was possible to map the <span class="hlt">microwave</span> brightness temperature (TB), and thus the soil moisture, over a large area. In this case the area was approximately 8 by 20 km. The moisture conditions ranged from very dry, <2% by volume, to quite wet, >15%, after a heavy rain. The rain amounts ranged from less than 10 mm to more than 50 mm over the area mapped with the PBMR. With the PBMR we were able to observe the spatial variations of the rain amounts and the temporal variation as the soil dried. The TB values were registered to a Universal Transverse Mercator grid so that they could be compared to the rain gage readings and to the ground measurements of soil moisture in the 0- to 5-cm layer. The decreases in TB were well correlated with the rainfall amounts, R2 = 0.9, and the comparison of Tg with soil moisture was also good with an R2 of about 0.8. For the latter, there was some dependence of the relation on location, which may be due to soil or vegetation variations over the area mapped. The application of these data to runoff forecasts and flux estimates will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950040483&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddmr','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950040483&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddmr"><span>Statistics and topology of the COBE differential <span class="hlt">microwave</span> <span class="hlt">radiometer</span> first-year sky maps</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smoot, G. F.; Tenorio, L.; Banday, A. J.; Kogut, A.; Wright, E. L.; Hinshaw, G.; Bennett, C. L.</p> <p>1994-01-01</p> <p>We use statistical and topological quantities to test the Cosmic Background Explorer (COBE) Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (DMR) first-year sky maps against the hypothesis that the observed temperature fluctuations reflect Gaussian initial density perturbations with random phases. Recent papers discuss specific quantities as discriminators between Gaussian and non-Gaussian behavior, but the treatment of instrumental noise on the data is largely ignored. The presence of noise in the data biases many statistical quantities in a manner dependent on both the noise properties and the unknown cosmic <span class="hlt">microwave</span> background temperature field. Appropriate weighting schemes can minimize this effect, but it cannot be completely eliminated. Analytic expressions are presented for these biases, and Monte Carlo simulations are used to assess the best strategy for determining cosmologically interesting information from noisy data. The genus is a robust discriminator that can be used to estimate the power-law quadrupole-normalized amplitude, Q(sub rms-PS), independently of the two-point correlation function. The genus of the DMR data is consistent with Gaussian initial fluctuations with Q(sub rms-PS) = (15.7 +/- 2.2) - (6.6 +/- 0.3)(n - 1) micro-K, where n is the power-law index. Fitting the rms temperature variations at various smoothing angles gives Q(sub rms-PS) = 13.2 +/- 2.5 micro-K and n = 1.7(sup (+0.3) sub (-0.6)). While consistent with Gaussian fluctuations, the first year data are only sufficient to rule out strongly non-Gaussian distributions of fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10186401','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10186401"><span>Correlation function analysis of the COBE differential <span class="hlt">microwave</span> <span class="hlt">radiometer</span> sky maps</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lineweaver, Charles Howe</p> <p>1994-08-01</p> <p>The Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (DMR) aboard the COBE satellite has detected anisotropies in the cosmic <span class="hlt">microwave</span> background (CMB) radiation. A two-point correlation function analysis which helped lead to this discovery is presented in detail. The results of a correlation function analysis of the two year DMR data set is presented. The first and second year data sets are compared and found to be reasonably consistent. The positive correlation for separation angles less than ~20° is robust to Galactic latitude cuts and is very stable from year to year. The Galactic latitude cut independence of the correlation function is strong evidence that the signal is not Galactic in origin. The statistical significance of the structure seen in the correlation function of the first, second and two year maps is respectively > 9σ, > 10σ and > 18σ above the noise. The noise in the DMR sky maps is correlated at a low level. The structure of the pixel temperature covariance matrix is given. The noise covariance matrix of a DMR sky map is diagonal to an accuracy of better than 1%. For a given sky pixel, the dominant noise covariance occurs with the ring of pixels at an angular separation of 60° due to the 60° separation of the DMR horns. The mean covariance of 60° is 0.45%$+0.18\\atop{-0.14}$ of the mean variance. The noise properties of the DMR maps are thus well approximated by the noise properties of maps made by a single-beam experiment. Previously published DMR results are not significantly affected by correlated noise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994PhDT.........2L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994PhDT.........2L"><span>Correlation function analysis of the COBE differential <span class="hlt">microwave</span> <span class="hlt">radiometer</span> sky maps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lineweaver, C. H.</p> <p>1994-08-01</p> <p>The Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (DMR) aboard the COBE satellite has detected anisotropies in the cosmic <span class="hlt">microwave</span> background (CMB) radiation. A two-point correlation function analysis which helped lead to this discovery is presented in detail. The results of a correlation function analysis of the two year DMR data set is presented. The first and second year data sets are compared and found to be reasonably consistent. The positive correlation for separation angles less than approximately 20 deg is robust to Galactic latitude cuts and is very stable from year to year. The Galactic latitude cut independence of the correlation function is strong evidence that the signal is not Galactic in origin. The statistical significance of the structure seen in the correlation function of the first, second and two year maps is respectively greater than 9(sigma), greater than 10(sigma) and greater than 18(sigma) above the noise. The noise in the DMR sky maps is correlated at a low level. The structure of the pixel temperature covariance matrix is given. The noise covariance matrix of a DMR sky map is diagonal to an accuracy of better than 1%. For a given sky pixel, the dominant noise covariance occurs with the ring of pixels at an angular separation of 60 deg due to the 60 deg separation of the DMR horns. The mean covariance of 60 deg is 0.45%-0.14+0.18 of the mean variance. The noise properties of the DMR maps are thus well approximated by the noise properties of maps made by a single-beam experiment. Previously published DMR results are not significantly affected by correlated noise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRF..119..550R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRF..119..550R"><span>Snow stratigraphic heterogeneity within ground-based passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> footprints: Implications for emission modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rutter, Nick; Sandells, Mel; Derksen, Chris; Toose, Peter; Royer, Alain; Montpetit, Benoit; Langlois, Alex; Lemmetyinen, Juha; Pulliainen, Jouni</p> <p>2014-03-01</p> <p>Two-dimensional measurements of snowpack properties (stratigraphic layering, density, grain size, and temperature) were used as inputs to the multilayer Helsinki University of Technology (HUT) <span class="hlt">microwave</span> emission model at a centimeter-scale horizontal resolution, across a 4.5 m transect of ground-based passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> footprints near Churchill, Manitoba, Canada. Snowpack stratigraphy was complex (between six and eight layers) with only three layers extending continuously throughout the length of the transect. Distributions of one-dimensional simulations, accurately representing complex stratigraphic layering, were evaluated using measured brightness temperatures. Large biases (36 to 68 K) between simulated and measured brightness temperatures were minimized (-0.5 to 0.6 K), within measurement accuracy, through application of grain scaling factors (2.6 to 5.3) at different combinations of frequencies, polarizations, and model extinction coefficients. Grain scaling factors compensated for uncertainty relating optical specific surface area to HUT effective grain size inputs and quantified relative differences in scattering and absorption properties of various extinction coefficients. The HUT model required accurate representation of ice lenses, particularly at horizontal polarization, and large grain scaling factors highlighted the need to consider microstructure beyond the size of individual grains. As variability of extinction coefficients was strongly influenced by the proportion of large (hoar) grains in a vertical profile, it is important to consider simulations from distributions of one-dimensional profiles rather than single profiles, especially in sub-Arctic snowpacks where stratigraphic variability can be high. Model sensitivity experiments suggested that the level of error in field measurements and the new methodological framework used to apply them in a snow emission model were satisfactory. Layer amalgamation showed that a three</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713763M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713763M"><span>The New Version of Brightness Temperature Product of <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> AMSR2 onboard GCOM-W1 Satellite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maeda, Takashi; Imaoka, Keiji; Kasahara, Marehito</p> <p>2015-04-01</p> <p>The Japan Aerospace Exploration Agency (JAXA) launched the GCOM-W1 (Global Change Observation Mission 1st - <span class="hlt">Water</span>) satellite on 17 May 2012 (UT). The main mission of the GCOM-W1 satellite is to monitor the global <span class="hlt">water</span> cycle, for which it has onboard the Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span>-2 (AMSR2). The AMSR2 has multifrequency <span class="hlt">microwave</span> receivers, and like many other satellite-borne <span class="hlt">microwave</span> <span class="hlt">radiometers</span> currently in orbit, its multifrequency feedhorns share a single rotating antenna dish. Because AMSR2 is designed to make a sharp antenna beam for each frequency, the FOV (field of view) size of each frequency differs substantially from one another: the higher the frequency, the smaller the FOV size. Therefore, the multifrequency data (brightness temperature, TB) represent responses of areas quite different from one another, even if the multifrequency TB values are obtained by the same measurement. Lack of consideration of the difference in FOV sizes will be an important reason for the deterioration of the accuracy of geophysical values retrieved from multifrequency TB values. To solve this problem, we can consider to replicate a large FOV of low-target frequency by adequately summing small FOV of high-source frequency spreading within it. One way to achieve this is with the Backus-Gilbert (BG) method, and there have been many studies related to this issue. The BG method provides a way to calculate the intensities for small-source FOVs to replicate a large-target FOV as accurately as possible. TB values that correspond to source FOVs (source TB values) are averaged using these intensities as weighting coefficients. Thus, the TB synthesized from the source TB values, i.e., the weighted mean of the source TB values becomes equivalent to the source frequency's TB measured by a target FOV. The source frequency's synthesized TB and the target frequency's TB enable us to evaluate more accurately the difference in the <span class="hlt">microwave</span> emission characteristics between the two</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.595a2017K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.595a2017K"><span>The <span class="hlt">water</span> vapour <span class="hlt">radiometer</span> of Paranal: homogeneity of precipitable <span class="hlt">water</span> vapour from two years of operations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kerber, Florian; Querel, Richard R.; Neureiter, Bianca</p> <p>2015-04-01</p> <p>A Low Humidity and Temperature Profiling (LHATPRO) <span class="hlt">microwave</span> <span class="hlt">radiometer</span>, manufactured by <span class="hlt">Radiometer</span> Physics GmbH (RPG), is used to monitor sky conditions over ESO's Paranal observatory in support of VLT science operations. The unit measures several channels across the strong <span class="hlt">water</span> vapour emission line at 183 GHz, necessary for resolving the low levels of precipitable <span class="hlt">water</span> vapour (PWV) that are prevalent on Paranal (median ∼2.4 mm). The instrument consists of a humidity profiler (183-191 GHz), a temperature profiler (51-58 GHz), and an infrared camera (∼10 μm) for cloud detection. We present a statistical analysis of the homogeneity of all-sky PWV using 24 months of PWV observations. The question we tried to address was whether PWV is homogeneous enough across the sky such that service mode observations with the VLT can routinely be conducted with a user-provided constraint for PWV measured at zenith. We find the PWV over Paranal to be remarkably homogeneous across the sky down to 27.5° elevation with a median variation of 0.07 mm (rms). The homogeneity is a function of the absolute PWV but the relative variation is fairly constant at 2 to 3% (rms). Such variations will not be a significant issue for analysis of astronomical data. Users at ESO can specify PWV - measured at zenith - as an ambient constraint in service mode to enable, for instance, very demanding observations in the infrared. We conclude that in general it will not be necessary to add another observing constraint for PWV homogeneity to ensure integrity of observations. For demanding observations requiring very low PWV, where the relative variation is higher, the optimum support could be provided by observing with the LHATPRO in the same line-of-sight simultaneously. Such a mode of operations has already been tested but will have to be justified in terms of scientific gain before implementation can be considered. We plan to extend our analysis of PWV variations covering a larger parameters space</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P41B2075S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P41B2075S"><span>Forecasting Juno <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Observations of Jupiter's Synchrotron Emission from Data Reconstruction Methods and Theoretical Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Santos-Costa, D.; Bolton, S. J.; Adumitroaie, V.; Janssen, M.; Levin, S.; Sault, R. J.; De Pater, I.; Tao, C.</p> <p>2015-12-01</p> <p>The Juno spacecraft will go into polar orbit after it arrives at Jupiter in mid-2016. Between November 2016 and March 2017, six <span class="hlt">MicroWave</span> <span class="hlt">Radiometers</span> will collect information on Jupiter's atmosphere and electron belt. Here we present simulations of MWR observations of the electron belt synchrotron emission, and discuss the features and dynamical behavior of this emission when observations are carried out from inside the radiation zone. We first present our computation method. We combine a three-dimensional tomographic reconstruction method of Earth-based observations and a theoretical model of Jupiter's electron belt to constrain the calculations of the volume emissivity of the synchrotron radiation for any frequency, location in the Jovian inner magnetosphere (radial distance < 4 Rj), and observational direction. Values of the computed emissivity are incorporated into a synchrotron simulator to predict Juno MWR measurements (full sky maps and temperatures) at any time of the mission. Samples of simulated MWR observations are presented and examined for different segments of Juno trajectory. We also present results of our ongoing investigation of the radiation zone distribution around the planet and the sources of variation on different time-scales. We show that a better understanding of the spatial distribution and variability of the electron belt is key to realistically forecast Juno MWR measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950035594&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddmr','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950035594&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddmr"><span>Comments on the statistical analysis of excess variance in the COBE differential <span class="hlt">microwave</span> <span class="hlt">radiometer</span> maps</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wright, E. L.; Smoot, G. F.; Kogut, A.; Hinshaw, G.; Tenorio, L.; Lineweaver, C.; Bennett, C. L.; Lubin, P. M.</p> <p>1994-01-01</p> <p>Cosmic anisotrophy produces an excess variance sq sigma(sub sky) in the Delta maps produced by the Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (DMR) on cosmic background explorer (COBE) that is over and above the instrument noise. After smoothing to an effective resolution of 10 deg, this excess sigma(sub sky)(10 deg), provides an estimate for the amplitude of the primordial density perturbation power spectrum with a cosmic uncertainty of only 12%. We employ detailed Monte Carlo techniques to express the amplitude derived from this statistic in terms of the universal root mean square (rms) quadrupole amplitude, (Q sq/RMS)(exp 0.5). The effects of monopole and dipole subtraction and the non-Gaussian shape of the DMR beam cause the derived (Q sq/RMS)(exp 0.5) to be 5%-10% larger than would be derived using simplified analytic approximations. We also investigate the properties of two other map statistics: the actual quadrupole and the Boughn-Cottingham statistic. Both the sigma(sub sky)(10 deg) statistic and the Boughn-Cottingham statistic are consistent with the (Q sq/RMS)(exp 0.5) = 17 +/- 5 micro K reported by Smoot et al. (1992) and Wright et al. (1992).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890017918','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890017918"><span>Attitude angle effects on Nimbus-7 Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> radiances and geophysical parameter retrievals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Macmillan, Daniel S.; Han, Daesoo</p> <p>1989-01-01</p> <p>The attitude of the Nimbus-7 spacecraft has varied significantly over its lifetime. A summary of the orbital and long-term behavior of the attitude angles and the effects of attitude variations on Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) brightness temperatures is presented. One of the principal effects of these variations is to change the incident angle at which the SMMR views the Earth's surface. The brightness temperatures depend upon the incident angle sensitivities of both the ocean surface emissivity and the atmospheric path length. Ocean surface emissivity is quite sensitive to incident angle variation near the SMMR incident angle, which is about 50 degrees. This sensitivity was estimated theoretically for a smooth ocean surface and no atmosphere. A 1-degree increase in the angle of incidence produces a 2.9 C increase in the retrieved sea surface temperature and a 5.7 m/sec decrease in retrieved sea surface wind speed. An incident angle correction is applied to the SMMR radiances before using them in the geophysical parameter retrieval algorithms. The corrected retrieval data is compared with data obtained without applying the correction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012cosp...39.2030U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39.2030U"><span>Evolution of Mesoscale Convective System over the South Western Peninsular India: Observations from <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> and Simulations using WRF</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uma, K. N.; Krishna Moorthy, K.; Sijikumar, S.; Renju, R.; Tinu, K. A.; Raju, Suresh C.</p> <p>2012-07-01</p> <p>Meso-scale Convective Systems (MCS) are important in view of their large cumulous build-up, vertical extent, short horizontal extent and associated thundershowers. The <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Profiler (MRP) over the equatorial coastal station Thiruvanathapuram (Trivandrum, 8.55oN, 76.9oE), has been utilized to understand the genesis of Mesoscale convective system (MCS), that occur frequently during the pre-monsoon season. Examination of the measurement of relative humidity, temperature and cloud liquid <span class="hlt">water</span> measurements, over the zenith and two scanning elevation angles (15o) viewing both over the land and the sea respectively revealed that the MCS generally originate over the land during early afternoon hours, propagate seawards over the observational site and finally dissipate over the sea, with accompanying rainfall and latent heat release. The simulations obtained using Advanced Research-Weather Research and Forecast (WRF-ARW) model effectively reproduces the thermodynamical and microphysical properties of the MCS. The time duration and quantity of rainfall obtained by the simulations also well compared with the observations. Analysis also suggests that wind shear in the upper troposphere is responsible for the growth and the shape of the convective cloud.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999evga.conf..161G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999evga.conf..161G"><span>Comparison of atmospheric parameters estimated from VLBI, GPS and <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gradinarsky, L. P.; Haas, R.; Johansson, J. M.; Elgered, G.</p> <p>1999-03-01</p> <p>Very Long Baseline Interferometry (VLBI) is colocated with a permanent Global Positioning System (GPS) receiver and a <span class="hlt">Water</span> Vapour <span class="hlt">Radiometer</span> (WVR) at the Onsala Space Observatory (OSO). Both VLBI and GPS data are affected by the propagation delay of radio waves in the atmosphere, while the WVR is sensitive to the atmospheric emission close to the center of the 22 GHz <span class="hlt">water</span> vapour emission line and provides wet delay estimates. The authors present a comparison of estimated atmospheric parameters (equivalent zenith wetdelay and linear horizontal delay gradients) derived from an independent analysis of simultaneous VLBI, GPS and WVR observations. They study and compare the estimated parameters using different elevation cut off angles for the analysis of VLBI data with those obtained from the GPS and the WVR data analyses. The parameters are estimated for 90, 180 and 360 minutes long intervals, which allows to study the averaging effect on the integrated parameters of the turbulent atmosphere.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900062619&hterms=vine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dvine','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900062619&hterms=vine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dvine"><span>Initial results in the development of a synthetic aperture <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Le Vine, David M.; Kao, Michael; Tanner, Alan B.; Swift, Calvin T.; Griffis, Andrew</p> <p>1990-01-01</p> <p>A <span class="hlt">radiometer</span> that measures the complex correlation of the voltage from pairs of antennas at many different baselines is being developed. Each baseline produces a sample point in the Fourier transform of the scene, and a map of the scene is obtained after all measurements have been made by inverting the transform. A substantial reduction in the antenna collecting area required compared to a conventional imaging <span class="hlt">radiometer</span> can be obtained in this manner. An aircraft prototype being developed is a hybrid which uses real aperture antennas to obtain resolution along-track (stick antennas) and uses aperture synthesis to obtain resolution across-track. The prototype was flight-tested aboard the NASA P-3 in June 1988. During this flight a map was made of the Delmarva Peninsula south of NASA's Wallops Flight Facility. This initial map shows the major land/<span class="hlt">water</span> features and compares very favorably with a Landsat image of the area, suggesting a bright outlook for the development of this technique in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840038167&hterms=water+speed&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dwater%2Bspeed','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840038167&hterms=water+speed&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dwater%2Bspeed"><span>Global measurements of sea surface temperature, wind speed and atmospheric <span class="hlt">water</span> content from satellite <span class="hlt">microwave</span> radiometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Njoku, E. G.; Swanson, L.</p> <p>1983-01-01</p> <p>The Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) was launched on the Seasat and Nimbus 7 satellites in 1978. The SMMR has the ability to measure sea surface temperature and wind speed with the aid of <span class="hlt">microwaves</span>. In addition, the instrument was designed to measure <span class="hlt">water</span> vapor and cloud liquid <span class="hlt">water</span> with better spatial resolution than previous <span class="hlt">microwave</span> <span class="hlt">radiometers</span>, and to make sea-ice measurements with higher precision. A description is presented of the results of global analyses of sea surface temperature, wind speed, <span class="hlt">water</span> vapor, and cloud liquid <span class="hlt">water</span>, taking into account data provided by the SMMR on the Seasat satellite. It is found that the SMMR data show good self-consistency, and can usefully measure global distributions of sea surface temperatures, surface winds, <span class="hlt">water</span> vapor, and cloud liquid <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840038167&hterms=measure+temperature+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmeasure%2Btemperature%2Bwater','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840038167&hterms=measure+temperature+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmeasure%2Btemperature%2Bwater"><span>Global measurements of sea surface temperature, wind speed and atmospheric <span class="hlt">water</span> content from satellite <span class="hlt">microwave</span> radiometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Njoku, E. G.; Swanson, L.</p> <p>1983-01-01</p> <p>The Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) was launched on the Seasat and Nimbus 7 satellites in 1978. The SMMR has the ability to measure sea surface temperature and wind speed with the aid of <span class="hlt">microwaves</span>. In addition, the instrument was designed to measure <span class="hlt">water</span> vapor and cloud liquid <span class="hlt">water</span> with better spatial resolution than previous <span class="hlt">microwave</span> <span class="hlt">radiometers</span>, and to make sea-ice measurements with higher precision. A description is presented of the results of global analyses of sea surface temperature, wind speed, <span class="hlt">water</span> vapor, and cloud liquid <span class="hlt">water</span>, taking into account data provided by the SMMR on the Seasat satellite. It is found that the SMMR data show good self-consistency, and can usefully measure global distributions of sea surface temperatures, surface winds, <span class="hlt">water</span> vapor, and cloud liquid <span class="hlt">water</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4822306T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4822306T"><span>Chang'E <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Data Calibration with LRO Diviner Data and Machine Learning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsang, Ken; Hu, Guo-Ping; Zheng, Yong-Chun; This work is supported by BNU-HKBU United International College Research Grant R201626, Zhuhai Premier Discipline Enhancement Grant code: R1050, and Science and Technology Development Fund in Macao SAR 039/2013/A2</p> <p>2016-10-01</p> <p>Following usual practice in <span class="hlt">microwave</span> remote sensing, raw data from multi-channel <span class="hlt">microwave</span> <span class="hlt">radiometers</span> (MR) onboard the Chinese Chang'E lunar obiters (CE1 & CE2) were acquired as observed antenna voltages, which were then calibrated and converted to brightness temperatures (TB) by a two-point calibration procedure. While the CE cold calibration antenna is supposed to point to the deep space and taking data for the cold reference point in the two-point calibration scheme, in reality, it picked up undesirable thermal <span class="hlt">microwave</span> radiation from the lunar surface. Thus the "cold" reference point is not exactly the 2.7K cosmic background assumed and this affects the quality of the calibration.In this work, the small but puzzling differences between the two sets of Level 2C MR data released for CE1 & 2 are attributed to the difference in orbital altitudes between CE1 & 2. This leads to the different degrees of contamination to the cold antenna on CE1 & 2 by thermal radiations from the lunar surface, which showed up as persistent lower night-time TB values in the Level 2C CE2 dataset.We proposed a machine learning approach applied directly to pre-Level 2C data in the voltages to TB convertion process. Since all the antenna voltage data as well as the high temperature referencing point in the calibration procedure are directly measurable, optimized regression algorithms have been employed to determine the effective low temperature referencing points and obtain a single set of statistical consistent TB by combining raw data from CE1 & 2, due to the fact that seasonal variations are less than resolution of the CE MR data from low to medium latitudes.Finally, the Lunar Reconnaissance Orbiter (LRO) Diviner IR data are used as constraints on the boundary condition of the top layer regolith temperature to obtain a consistent sub-surface temperature profile, from which the measured CE MR data can be computed through multi-layer radiation transfer model. This step removes most of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010stt..conf..389C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010stt..conf..389C"><span><span class="hlt">Water</span> Vapor <span class="hlt">Radiometer</span> for ALMA: Optical Design and Verification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cherednichenko, S.; Emrich, A.; Peacocke, T.</p> <p>2010-03-01</p> <p>Atacama Large Millimeter wave Array (ALMA) is being built at a high altitude Atacama Desert in Chile. It will consist of 50 12m telescopes with heterodyne instruments to cover a large frequency range from about 30GHz to nearly 1THz. In order to facilitate the interferometer mode of operation all receivers have to be phase synchronized. It will be accomplished by phase locking of all local oscillators from a single reference source. However, a noticeable part of the phase error is caused as the signal propagates through the Earth atmosphere. Since this effect originates from the fluctuations of <span class="hlt">water</span> vapors, it can be accounted for by carefully measuring the spectral width of one of <span class="hlt">water</span> vapor resonance absorption lines. This will be done with a submillimeter heterodyne <span class="hlt">radiometer</span>, <span class="hlt">Water</span> Vapor <span class="hlt">Radiometer</span> (WVR). WVR will measure the sky brightness temperature in the beam path of every telescope across the 183GHz <span class="hlt">water</span> line with a spectral resolution of about 1GHz. Accuracy of the calculated optical delay is determined by the combination of the radiometric accuracy of the WVR and of the errors originated in the WVR illumination of the telescope. We will describe major challenges in the design of the WVR to comply with the stringent requirements set to the WVR. Several approaches to simulate the quasioptical waveguide which brings the signal from the telescope's subreflector to the mixer horn, were used: fundamental mode Gaussian beam propagation, combined ray tracing with diffraction effects (using package ZEMAX), and a full vector electromagnetic simulations (using GRASP). The computational time increases rapidly from the first method to the last one. We have found that ZEMAX results are quite close to the one from GRASP, however obtained with nearly instant computation, which allows multiple iterations during system optimization. The beam pattern of the WVR and of WVR with the optical Relay (used to bring the signal from the telescope's main axis to the WVR input</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000021399','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000021399"><span>A TRMM <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Rain Rate Estimation Method with Convective and Stratiform Discrimination</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prabhakara, C.; Iacovazzi, R., Jr.; Weinman, J. A.; Dalu, G.</p> <p>1999-01-01</p> <p>Tropical Rainfall Measuring Mission (TRMM) <span class="hlt">Microwave</span> Imager (TMI) <span class="hlt">radiometer</span> brightness temperature data in the 85 GHz channel (T85) reveal distinct local minima (T85min) in a regional map containing a Mesoscale Convective System (MCS). This is because of relatively small footprint size (approximately 5.5 km) and strong extinction properties in this channel of the TMI. A map of surface rain rate for that region, deduced from simultaneous measurements made by the Precipitation Radar (PR) on board the TRMM satellite, reveals that these T85(sub min), produced by scattering, correspond to local PR rain maxima. Utilizing the PR rain rate map as a guide, we infer empirically from TMI data the presence of three different kinds of thunderstorms or Cbs. These Cbs are classified as young, mature, and decaying types, and are assumed to have a scale of about 20 km on the average. Two parameters are used to classify these three kinds of Cbs based on the T85 data: a) the magnitude of scattering depression deduced from local T85(sub min) and b) the mean horizontal gradient of T85 around such minima. Knowing the category of a given Cb, we can estimate the rain rate associated with it. Such estimation is done with the help of relationships linking T85min to rain rate in each Cb type. Similarly, a weak background rain rate in all the areas where T85 is less than 260 K is deduced with another relationship linking T85 to rain rate. In our rain retrieval model, this background rain constitutes stratiform rain where the Cbs are absent. Initially, these relationships are optimized or tuned utilizing the PR and TMI data of a few MCS events. After such tuning, the model is applied to independent MCS cases. The areal distribution of light (1-10 mm/hr), moderate (10-20 mm/hr), and intense (>= 20 mm/hr) rain rates are retrieved satisfactorily. Accuracy in the estimates of the light, moderate, and intense rain areas and the mean rain rates associated with such areas in these independent MCS</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JMoSp.328....7T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JMoSp.328....7T"><span>Spectroscopy underlying <span class="hlt">microwave</span> remote sensing of atmospheric <span class="hlt">water</span> vapor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tretyakov, M. Yu.</p> <p>2016-10-01</p> <p>The paper presents a spectroscopist's view on the problem of recovery of the atmosphere humidity profile using modern <span class="hlt">microwave</span> <span class="hlt">radiometers</span>. Fundamental equations, including the description of their limitations, related to modeling of atmospheric <span class="hlt">water</span> vapor absorption are given. A review of all reported to date experimental studies aimed at obtaining corresponding numerical parameters is presented. Best estimates of these parameters related to the Voigt (Lorentz, Gross, Van Vleck - Weisskopf and other equivalent) profile based modeling of the 22- and 183-GHz <span class="hlt">water</span> vapor diagnostic lines and to non-resonance absorption as well as corresponding uncertainties are made on the basis of their comparative analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.2361S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.2361S"><span>Passive <span class="hlt">Microwave</span> Soil Moisture Retrieval through Combined Radar/<span class="hlt">Radiometer</span> Ground Based Simulator with Special Reference to Dielectric Schemes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Srivastava, Prashant K., ,, Dr.; O'Neill, Peggy, ,, Dr.</p> <p>2014-05-01</p> <p>Soil moisture is an important element for weather and climate prediction, hydrological sciences, and applications. Hence, measurements of this hydrologic variable are required to improve our understanding of hydrological processes, ecosystem functions, and the linkages between the Earth's <span class="hlt">water</span>, energy, and carbon cycles (Srivastava et al. 2013). The retrieval of soil moisture depends not only on parameterizations in the retrieval algorithm but also on the soil dielectric mixing models used (Behari 2005). Although a number of soil dielectric mixing models have been developed, testing these models for soil moisture retrieval has still not been fully explored, especially with SMAP-like simulators. The main objective of this work focuses on testing different dielectric models for soil moisture retrieval using the Combined Radar/<span class="hlt">Radiometer</span> (ComRAD) ground-based L-band simulator developed jointly by NASA/GSFC and George Washington University (O'Neill et al., 2006). The ComRAD system was deployed during a field experiment in 2012 in order to provide long active/passive measurements of two crops under controlled conditions during an entire growing season. L-band passive data were acquired at a look angle of 40 degree from nadir at both horizontal & vertical polarization. Currently, there are many dielectric models available for soil moisture retrieval; however, four dielectric models (Mironov, Dobson, Wang & Schmugge and Hallikainen) were tested here and found to be promising for soil moisture retrieval (some with higher performances). All the above-mentioned dielectric models were integrated with Single Channel Algorithms using H (SCA-H) and V (SCA-V) polarizations for the soil moisture retrievals. All the ground-based observations were collected from test site-United States Department of Agriculture (USDA) OPE3, located a few miles away from NASA GSFC. Ground truth data were collected using a theta probe and in situ sensors which were then used for validation. Analysis</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960003215','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960003215"><span>Millimeter-wave Imaging <span class="hlt">Radiometer</span> (MIR) data processing and development of <span class="hlt">water</span> vapor retrieval algorithms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, L. Aron</p> <p>1995-01-01</p> <p>This document describes the progress of the task of the Millimeter-wave Imaging <span class="hlt">Radiometer</span> (MIR) data processing and the development of <span class="hlt">water</span> vapor retrieval algorithms, for the second six-month performing period. Aircraft MIR data from two 1995 field experiments were collected and processed with a revised data processing software. Two revised versions of <span class="hlt">water</span> vapor retrieval algorithm were developed, one for the execution of retrieval on a supercomputer platform, and one for using pressure as the vertical coordinate. Two implementations of incorporating products from other sensors into the <span class="hlt">water</span> vapor retrieval system, one from the Special Sensor <span class="hlt">Microwave</span> Imager (SSM/I), the other from the High-resolution Interferometer Sounder (HIS). <span class="hlt">Water</span> vapor retrievals were performed for both airborne MIR data and spaceborne SSM/T-2 data, during field experiments of TOGA/COARE, CAMEX-1, and CAMEX-2. The climatology of <span class="hlt">water</span> vapor during TOGA/COARE was examined by SSM/T-2 soundings and conventional rawinsonde.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990041153','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990041153"><span>Millimeter-Wave Imaging <span class="hlt">Radiometer</span> (MIR) Data Processing and Development of <span class="hlt">Water</span> Vapor Retrieval Algorithms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, L. Aron</p> <p>1998-01-01</p> <p>This document describes the final report of the Millimeter-wave Imaging <span class="hlt">Radiometer</span> (MIR) Data Processing and Development of <span class="hlt">Water</span> Vapor Retrieval Algorithms. Volumes of radiometric data have been collected using airborne MIR measurements during a series of field experiments since May 1992. Calibrated brightness temperature data in MIR channels are now available for studies of various hydrological parameters of the atmosphere and Earth's surface. <span class="hlt">Water</span> vapor retrieval algorithms using multichannel MIR data input are developed for the profiling of atmospheric humidity. The retrieval algorithms are also extended to do three-dimensional mapping of moisture field using continuous observation provided by airborne sensor MIR or spaceborne sensor SSM/T-2. Validation studies for <span class="hlt">water</span> vapor retrieval are carried out through the intercomparison of collocated and concurrent measurements using different instruments including lidars and radiosondes. The developed MIR <span class="hlt">water</span> vapor retrieval algorithm is capable of humidity profiling under meteorological conditions ranging from clear column to moderately cloudy sky. Simulative <span class="hlt">water</span> vapor retrieval studies using extended <span class="hlt">microwave</span> channels near 183 and 557 GHz strong absorption lines indicate feasibility of humidity profiling to layers in the upper troposphere and improve the overall vertical resolution through the atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28613264','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28613264"><span>A Novel Sensor Based on a Single-Pixel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> for Warm Object Counting: Concept Validation and IoT Perspectives.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alimenti, Federico; Bonafoni, Stefania; Roselli, Luca</p> <p>2017-06-14</p> <p>Controlled measurements by a low-cost single-pixel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> operating at 12.65 GHz were carried out to assess the detection and counting capability for targets warmer than the surroundings. The adopted reference test targets were pre-warmed <span class="hlt">water</span> and oil; and a hand, both naked and wearing a glove. The results showed the reliability of <span class="hlt">microwave</span> radiometry for counting operations under controlled conditions, and its effectiveness at detecting even warm targets masked by unheated dielectric layers. An electromagnetic model describing the scenario sensed by the <span class="hlt">radiometer</span> antenna is proposed, and comparison with the experimental observations shows a good agreement. The measurements prove that reliable counting is enabled by an antenna temperature increment, for each target sample added, of around 1 K. Starting from this value, an analysis of the antenna filling factor was performed to provide an instrument useful for evaluating real applicability in many practical situations. This study also allows the direct people counting problem to be addressed, providing preliminary operational indications, reference numbers and experimental validation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870001672','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870001672"><span>Design and development of a multibeam 1.4 GHz pushbroom <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lawrence, R. W.; Bailey, M. C.; Harrington, R. F.; Hearn, C. P.; Wells, J. G.; Stanley, W. D.</p> <p>1986-01-01</p> <p>The design and operation of a multiple beam, digital signal processing <span class="hlt">radiometer</span> are discussed. The discussion includes a brief description of each major subsystem and an overall explanation of the hardware requirements and operation. A series of flight tests was conducted in which sea-truth sites, as well as an existing <span class="hlt">radiometer</span> were used to verify the Pushbroom <span class="hlt">Radiometer</span> performance. The results of these tests indicate that the Pushbroom <span class="hlt">Radiometer</span> did meet the sensitivity design goal of 1.0 kelvin, and exceeded the accuracy requirement of 2.0 kelvin. Additional performance characteristics and test results are also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000114843','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000114843"><span>A Texture-Polarization Method for Estimating Convective/Stratiform Precipitation Area Coverage from Passive <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Olson, William S.; Hong, Ye; Kummerow, Christian D.; Turk, Joseph; Einaudi, Franco (Technical Monitor)</p> <p>2000-01-01</p> <p>Observational and modeling studies have described the relationships between convective/stratiform rain proportion and the vertical distributions of vertical motion, latent heating, and moistening in mesoscale convective systems. Therefore, remote sensing techniques which can quantify the relative areal proportion of convective and stratiform, rainfall can provide useful information regarding the dynamic and thermodynamic processes in these systems. In the present study, two methods for deducing the convective/stratiform areal extent of precipitation from satellite passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> measurements are combined to yield an improved method. If sufficient <span class="hlt">microwave</span> scattering by ice-phase precipitating hydrometeors is detected, the method relies mainly on the degree of polarization in oblique-view, 85.5 GHz radiances to estimate the area fraction of convective rain within the <span class="hlt">radiometer</span> footprint. In situations where ice scattering is minimal, the method draws mostly on texture information in <span class="hlt">radiometer</span> imagery at lower <span class="hlt">microwave</span> frequencies to estimate the convective area fraction. Based upon observations of ten convective systems over ocean and nine systems over land, instantaneous 0.5 degree resolution estimates of convective area fraction from the Tropical Rainfall Measuring Mission <span class="hlt">Microwave</span> Imager (TRMM TMI) are compared to nearly coincident estimates from the TRMM Precipitation Radar (TRMM PR). The TMI convective area fraction estimates are slightly low-biased with respect to the PR, with TMI-PR correlations of 0.78 and 0.84 over ocean and land backgrounds, respectively. TMI monthly-average convective area percentages in the tropics and subtropics from February 1998 exhibit the greatest values along the ITCZ and in continental regions of the summer (southern) hemisphere. Although convective area percentages. from the TMI are systematically lower than those from the PR, monthly rain patterns derived from the TMI and PR rain algorithms are very similar</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140002292','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140002292"><span>Integrating a <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> into Radar Hardware for Simultaneous Data Collection Between the Instruments</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McLinden, Matthew; Piepmeier, Jeffrey</p> <p>2013-01-01</p> <p>The conventional method for integrating a <span class="hlt">radiometer</span> into radar hardware is to share the RF front end between the instruments, and to have separate IF receivers that take data at separate times. Alternatively, the radar and <span class="hlt">radiometer</span> could share the antenna through the use of a diplexer, but have completely independent receivers. This novel method shares the radar's RF electronics and digital receiver with the <span class="hlt">radiometer</span>, while allowing for simultaneous operation of the radar and <span class="hlt">radiometer</span>. Radars and <span class="hlt">radiometers</span>, while often having near-identical RF receivers, generally have substantially different IF and baseband receivers. Operation of the two instruments simultaneously is difficult, since airborne radars will pulse at a rate of hundreds of microseconds. <span class="hlt">Radiometer</span> integration time is typically 10s or 100s of milliseconds. The bandwidth of radar may be 1 to 25 MHz, while a <span class="hlt">radiometer</span> will have an RF bandwidth of up to a GHz. As such, the conventional method of integrating radar and <span class="hlt">radiometer</span> hardware is to share the highfrequency RF receiver, but to have separate IF subsystems and digitizers. To avoid corruption of the <span class="hlt">radiometer</span> data, the radar is turned off during the <span class="hlt">radiometer</span> dwell time. This method utilizes a modern radar digital receiver to allow simultaneous operation of a <span class="hlt">radiometer</span> and radar with a shared RF front end and digital receiver. The <span class="hlt">radiometer</span> signal is coupled out after the first down-conversion stage. From there, the radar transmit frequencies are heavily filtered, and the bands outside the transmit filter are amplified and passed to a detector diode. This diode produces a DC output proportional to the input power. For a conventional <span class="hlt">radiometer</span>, this level would be digitized. By taking this DC output and mixing it with a system oscillator at 10 MHz, the signal can instead be digitized by a second channel on the radar digital receiver (which typically do not accept DC inputs), and can be down-converted to a DC level again digitally. This</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150018099','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150018099"><span>Soil Moisture Active Passive (SMAP) <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Radio-Frequency Interference (RFI) Mitigation: Initial On-Orbit Results</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mohammed, Priscilla N.; Piepmeier, Jeffrey R.; Johnson, Joel T.; Aksoy, Mustafa; Bringer, Alexandra</p> <p>2015-01-01</p> <p>The Soil Moisture Active Passive (SMAP) mission, launched in January 2015, provides global measurements of soil moisture using a <span class="hlt">microwave</span> <span class="hlt">radiometer</span>. SMAPs <span class="hlt">radiometer</span> passband lies within the passive frequency allocation. However, both unauthorized in-band transmitters as well as out-of-band emissions from transmitters operating at frequencies adjacent to this allocated spectrum have been documented as sources of radio frequency interference (RFI) to the L-band <span class="hlt">radiometers</span> on SMOS and Aquarius. The spectral environment consists of high RFI levels as well as significant occurrences of low level RFI equivalent to 0.1 to 10 K. The SMAP ground processor reports the antenna temperature both before and after RFI mitigation is applied. The difference between these quantities represents the detected RFI level. The presentation will review the SMAP RFI detection and mitigation procedure and discuss early on-orbit RFI measurements from the SMAP <span class="hlt">radiometer</span>. Assessments of global RFI properties and source types will be provided, as well as the implications of these results for SMAP soil moisture measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C41D0720R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C41D0720R"><span>Detection of Rain-on-Snow (ROS) Events Using the Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span>-Earth Observing System (AMSR-E) and Weather Station Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ryan, E. M.; Brucker, L.; Forman, B. A.</p> <p>2015-12-01</p> <p>During the winter months, the occurrence of rain-on-snow (ROS) events can impact snow stratigraphy via generation of large scale ice crusts, e.g., on or within the snowpack. The formation of such layers significantly alters the electromagnetic response of the snowpack, which can be witnessed using space-based <span class="hlt">microwave</span> <span class="hlt">radiometers</span>. In addition, ROS layers can hinder the ability of wildlife to burrow in the snow for vegetation, which limits their foraging capability. A prime example occurred on 23 October 2003 in Banks Island, Canada, where an ROS event is believed to have caused the deaths of over 20,000 musk oxen. Through the use of passive <span class="hlt">microwave</span> remote sensing, ROS events can be detected by utilizing observed brightness temperatures (Tb) from AMSR-E. Tb observed at different <span class="hlt">microwave</span> frequencies and polarizations depends on snow properties. A wet snowpack formed from an ROS event yields a larger Tb than a typical dry snowpack would. This phenomenon makes observed Tb useful when detecting ROS events. With the use of data retrieved from AMSR-E, in conjunction with observations from ground-based weather station networks, a database of estimated ROS events over the past twelve years was generated. Using this database, changes in measured Tb following the ROS events was also observed. This study adds to the growing knowledge of ROS events and has the potential to help inform passive <span class="hlt">microwave</span> snow <span class="hlt">water</span> equivalent (SWE) retrievals or snow cover properties in polar regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930005603','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930005603"><span>Investigation of antenna pattern constraints for passive geosynchronous <span class="hlt">microwave</span> imaging <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gasiewski, A. J.; Skofronick, G. M.</p> <p>1992-01-01</p> <p>Progress by investigators at Georgia Tech in defining the requirements for large space antennas for passive <span class="hlt">microwave</span> Earth imaging systems is reviewed. In order to determine antenna constraints (e.g., the aperture size, illumination taper, and gain uncertainty limits) necessary for the retrieval of geophysical parameters (e.g., rain rate) with adequate spatial resolution and accuracy, a numerical simulation of the passive <span class="hlt">microwave</span> observation and retrieval process is being developed. Due to the small spatial scale of precipitation and the nonlinear relationships between precipitation parameters (e.g., rain rate, <span class="hlt">water</span> density profile) and observed brightness temperatures, the retrieval of precipitation parameters are of primary interest in the simulation studies. Major components of the simulation are described as well as progress and plans for completion. The overall goal of providing quantitative assessments of the accuracy of candidate geosynchronous and low-Earth orbiting imaging systems will continue under a separate grant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AMT.....8..315C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AMT.....8..315C"><span>Forecast indices from a ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> for operational meteorology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cimini, D.; Nelson, M.; Güldner, J.; Ware, R.</p> <p>2015-01-01</p> <p>Today, commercial <span class="hlt">microwave</span> <span class="hlt">radiometer</span> profilers (MWRPs) are robust and unattended instruments providing real-time, accurate atmospheric observations at ~ 1 min temporal resolution under nearly all weather conditions. Common commercial units operate in the 20-60 GHz frequency range and are able to retrieve profiles of temperature, vapour density, and relative humidity. Temperature and humidity profiles retrieved from MWRP data are used here to feed tools developed for processing radiosonde observations to obtain values of forecast indices (FIs) commonly used in operational meteorology. The FIs considered here include K index, total totals, KO index, Showalter index, T1 gust, fog threat, lifted index, S index (STT), Jefferson index, microburst day potential index (MDPI), Thompson index, TQ index, and CAPE (convective available potential energy). Values of FIs computed from radiosonde and MWRP-retrieved temperature and humidity profiles are compared in order to quantitatively demonstrate the level of agreement and the value of continuous FI updates. This analysis is repeated for two sites at midlatitude, the first one located at low altitude in central Europe (Lindenberg, Germany) and the second one located at high altitude in North America (Whistler, Canada). It is demonstrated that FIs computed from MWRPs well correlate with those computed from radiosondes, with the additional advantage of nearly continuous updates. The accuracy of MWRP-derived FIs is tested against radiosondes, taken as a reference, showing different performances depending upon index and environmental situation. Overall, FIs computed from MWRP retrievals agree well with radiosonde values, with correlation coefficients usually above 0.8 (with few exceptions). We conclude that MWRP retrievals can be used to produce meaningful FIs, with the advantage (with respect to radiosondes) of nearly continuous updates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AMTD....7.6971C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AMTD....7.6971C"><span>Forecast indices from ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> for operational meteorology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cimini, D.; Nelson, M.; Güldner, J.; Ware, R.</p> <p>2014-07-01</p> <p>Today, commercial <span class="hlt">microwave</span> <span class="hlt">radiometers</span> profilers (MWRP) are robust and unattended instruments providing real time accurate atmospheric observations at ~ 1 min temporal resolution under nearly all-weather conditions. Common commercial units operate in the 20-60 GHz frequency range and are able to retrieve profiles of temperature, vapour density, and relative humidity. Temperature and humidity profiles retrieved from MWRP data are used here to feed tools developed for processing radiosonde observations to obtain values of forecast indices (FI) commonly used in operational meteorology. The FI considered here include K index, Total Totals, KO index, Showalter index, T1 Gust, Fog Threat, Lifted Index, S Index (STT), Jefferson Index, MDPI, Thompson Index, TQ Index, and CAPE. Values of FI computed from radiosonde and MWRP-retrieved temperature and humidity profiles are compared in order to quantitatively demonstrate the level of agreement and the value of continuous FI updates. This analysis is repeated for two sites at midlatitude, the first one located at low altitude in Central Europe (Lindenberg, Germany), while the second one located at high altitude in North America (Whistler, Canada). It is demonstrated that FI computed from MWRP well correlate with those computed from radiosondes, with the additional advantage of nearly continuous update. The accuracy of MWRP-derived FI is tested against radiosondes, taken as a reference, showing different performances depending upon index and environmental situation. Overall, FI computed from MWRP retrievals agree well with radiosonde values, with correlation coefficients usually above 0.8 (with few exceptions). We conclude that MWRP retrievals can be used to produce meaningful FI, with the advantage (with respect to radiosondes) of nearly continuous update.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050000102&hterms=observation+identification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dobservation%2Bidentification','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050000102&hterms=observation+identification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dobservation%2Bidentification"><span>Polarimetric Scanning <span class="hlt">Radiometer</span> C and X Band <span class="hlt">Microwave</span> Observations During SMEX03</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jackson, Thomas J.; Bindlish, Rajat; Gasiewski, Albin J.; Stankov, Boba; Klein, Marian; Njoku, Eni G.; Bosch, David; Coleman, Thomas; Laymon, Charles; Starks, Patrick</p> <p>2004-01-01</p> <p>Soil Moisture Experiments 2003 (SMEX03) was the second in a series of field campaigns using the NOAA Polarimetric Scanning <span class="hlt">Radiometer</span> (PSR/CX) designed to validate brightness temperature data and soil moisture retrieval algorithms for the Advanced during SMEX03 were: calibration and validation of AMSR-E brightness temperature observations over different climate/vegetation regions of the US. (Alabama, Georgia, Oklahoma), identification of possible sources of Radio Frequency Interference (RFI), comparison of X-band observations from TRMM <span class="hlt">Microwave</span> Imager (TMI), AMSR-E and PSR/CX, and exploring the potential of soil moisture retrieval algorithms using C and X band imagery in diverse landscapes. In the current investigation, more than one hundred flightlines of PSR/CX data were extensively processed to produce gridded brightness temperature products for the four study regions. Variations associated with soil moisture were not as large as hoped for due to the lack of significant rainfall in Oklahoma. Observations obtained over Alabama include a wide range of soil moisture and vegetation conditions for C and X band frequencies. These results clearly showed a lack of sensitivity to rainfall/soil moisture under forest canopy cover. Quantitative comparisons made between the PSR/CX, AMSR-E for validated that both the PSR/CX and AMSR-E data were well calibrated. X band comparisons of the PSR/CX high resolution and AMSR-E and TMI low-resolution data indicated a linear scaling for the range of conditions studied in SMEX03. These results will form the basis for further soil moisture investigations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1184892-cloud-detection-algorithm-using-downwelling-infrared-radiance-measured-infrared-pyrometer-ground-based-microwave-radiometer','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1184892-cloud-detection-algorithm-using-downwelling-infrared-radiance-measured-infrared-pyrometer-ground-based-microwave-radiometer"><span>A cloud detection algorithm using the downwelling infrared radiance measured by an infrared pyrometer of the ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Ahn, M. H.; Han, D.; Won, H. Y.; ...</p> <p>2015-02-03</p> <p>For better utilization of the ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span>, it is important to detect the cloud presence in the measured data. Here, we introduce a simple and fast cloud detection algorithm by using the optical characteristics of the clouds in the infrared atmospheric window region. The new algorithm utilizes the brightness temperature (Tb) measured by an infrared <span class="hlt">radiometer</span> installed on top of a <span class="hlt">microwave</span> <span class="hlt">radiometer</span>. The two-step algorithm consists of a spectral test followed by a temporal test. The measured Tb is first compared with a predicted clear-sky Tb obtained by an empirical formula as a function of surface air temperaturemore » and <span class="hlt">water</span> vapor pressure. For the temporal test, the temporal variability of the measured Tb during one minute compares with a dynamic threshold value, representing the variability of clear-sky conditions. It is designated as cloud-free data only when both the spectral and temporal tests confirm cloud-free data. Overall, most of the thick and uniform clouds are successfully detected by the spectral test, while the broken and fast-varying clouds are detected by the temporal test. The algorithm is validated by comparison with the collocated ceilometer data for six months, from January to June 2013. The overall proportion of correctness is about 88.3% and the probability of detection is 90.8%, which are comparable with or better than those of previous similar approaches. Two thirds of discrepancies occur when the new algorithm detects clouds while the ceilometer does not, resulting in different values of the probability of detection with different cloud-base altitude, 93.8, 90.3, and 82.8% for low, mid, and high clouds, respectively. Finally, due to the characteristics of the spectral range, the new algorithm is found to be insensitive to the presence of inversion layers.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1184892','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1184892"><span>A cloud detection algorithm using the downwelling infrared radiance measured by an infrared pyrometer of the ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ahn, M. H.; Han, D.; Won, H. Y.; Morris, Victor R.</p> <p>2015-02-03</p> <p>For better utilization of the ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span>, it is important to detect the cloud presence in the measured data. Here, we introduce a simple and fast cloud detection algorithm by using the optical characteristics of the clouds in the infrared atmospheric window region. The new algorithm utilizes the brightness temperature (Tb) measured by an infrared <span class="hlt">radiometer</span> installed on top of a <span class="hlt">microwave</span> <span class="hlt">radiometer</span>. The two-step algorithm consists of a spectral test followed by a temporal test. The measured Tb is first compared with a predicted clear-sky Tb obtained by an empirical formula as a function of surface air temperature and <span class="hlt">water</span> vapor pressure. For the temporal test, the temporal variability of the measured Tb during one minute compares with a dynamic threshold value, representing the variability of clear-sky conditions. It is designated as cloud-free data only when both the spectral and temporal tests confirm cloud-free data. Overall, most of the thick and uniform clouds are successfully detected by the spectral test, while the broken and fast-varying clouds are detected by the temporal test. The algorithm is validated by comparison with the collocated ceilometer data for six months, from January to June 2013. The overall proportion of correctness is about 88.3% and the probability of detection is 90.8%, which are comparable with or better than those of previous similar approaches. Two thirds of discrepancies occur when the new algorithm detects clouds while the ceilometer does not, resulting in different values of the probability of detection with different cloud-base altitude, 93.8, 90.3, and 82.8% for low, mid, and high clouds, respectively. Finally, due to the characteristics of the spectral range, the new algorithm is found to be insensitive to the presence of inversion layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AMTD....7.9413A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AMTD....7.9413A"><span>A cloud detection algorithm using the downwelling infrared radiance measured by an infrared pyrometer of the ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahn, M.-H.; Han, D.; Won, H.-Y.; Morris, V.</p> <p>2014-09-01</p> <p>For a better utilization of the ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span>, it is important to detect the cloud presence in the measured data. Here, we introduce a simple and fast cloud detection algorithm by using the optical characteristics of the clouds in the infrared atmospheric window region. The new algorithm utilizes the brightness temperature (Tb) measured by an infrared <span class="hlt">radiometer</span> installed on top of a <span class="hlt">microwave</span> <span class="hlt">radiometer</span>. The two step algorithm consists of a spectral test followed by a temporal test. The measured Tb is first compared with a predicted clear sky Tb obtained by an empirical formula as a function of surface air temperature and <span class="hlt">water</span> vapor pressure. For the temporal test, the temporal variability of the measured Tb during one minute compares with a dynamic threshold value, representing the variability of the clear sky condition. It is designated as cloud free data only when both the spectral and temporal tests confirm a cloud free data. Overall, most of the thick and uniform clouds are successfully screened out by the spectral test, while the broken and fast-varying clouds are screened out by the temporal test. The algorithm is validated by comparison with the collocated ceilometer data for 6 months, from January 2013 to June 2013. The overall proportion correct is about 88.3% and the probability of detection is 90.8%, which are comparable with or better than those of previous similar approaches. Two thirds of failures occur when the new algorithm detects clouds while the ceilometer does not detect, resulting in different values of the probability of detection with different cloud base altitude, 93.8, 90.3, and 82.8% for low, mid, and high clouds, respectively. Finally, due to the characteristics of the spectral range, the new algorithm is found to be insensitive to the presence of inversion layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AMT.....8..553A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AMT.....8..553A"><span>A cloud detection algorithm using the downwelling infrared radiance measured by an infrared pyrometer of the ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahn, M.-H.; Han, D.; Won, H. Y.; Morris, V.</p> <p>2015-02-01</p> <p>For better utilization of the ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span>, it is important to detect the cloud presence in the measured data. Here, we introduce a simple and fast cloud detection algorithm by using the optical characteristics of the clouds in the infrared atmospheric window region. The new algorithm utilizes the brightness temperature (Tb) measured by an infrared <span class="hlt">radiometer</span> installed on top of a <span class="hlt">microwave</span> <span class="hlt">radiometer</span>. The two-step algorithm consists of a spectral test followed by a temporal test. The measured Tb is first compared with a predicted clear-sky Tb obtained by an empirical formula as a function of surface air temperature and <span class="hlt">water</span> vapor pressure. For the temporal test, the temporal variability of the measured Tb during one minute compares with a dynamic threshold value, representing the variability of clear-sky conditions. It is designated as cloud-free data only when both the spectral and temporal tests confirm cloud-free data. Overall, most of the thick and uniform clouds are successfully detected by the spectral test, while the broken and fast-varying clouds are detected by the temporal test. The algorithm is validated by comparison with the collocated ceilometer data for six months, from January to June 2013. The overall proportion of correctness is about 88.3% and the probability of detection is 90.8%, which are comparable with or better than those of previous similar approaches. Two thirds of discrepancies occur when the new algorithm detects clouds while the ceilometer does not, resulting in different values of the probability of detection with different cloud-base altitude, 93.8, 90.3, and 82.8% for low, mid, and high clouds, respectively. Finally, due to the characteristics of the spectral range, the new algorithm is found to be insensitive to the presence of inversion layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GMD.....9.2721D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GMD.....9.2721D"><span>RTTOV-gb - adapting the fast radiative transfer model RTTOV for the assimilation of ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Angelis, Francesco; Cimini, Domenico; Hocking, James; Martinet, Pauline; Kneifel, Stefan</p> <p>2016-08-01</p> <p>Ground-based <span class="hlt">microwave</span> <span class="hlt">radiometers</span> (MWRs) offer a new capability to provide continuous observations of the atmospheric thermodynamic state in the planetary boundary layer. Thus, they are potential candidates to supplement radiosonde network and satellite data to improve numerical weather prediction (NWP) models through a variational assimilation of their data. However in order to assimilate MWR observations, a fast radiative transfer model is required and such a model is not currently available. This is necessary for going from the model state vector space to the observation space at every observation point. The fast radiative transfer model RTTOV is well accepted in the NWP community, though it was developed to simulate satellite observations only. In this work, the RTTOV code has been modified to allow for simulations of ground-based upward-looking <span class="hlt">microwave</span> sensors. In addition, the tangent linear, adjoint, and K-modules of RTTOV have been adapted to provide Jacobians (i.e., the sensitivity of observations to the atmospheric thermodynamical state) for ground-based geometry. These modules are necessary for the fast minimization of the cost function in a variational assimilation scheme. The proposed ground-based version of RTTOV, called RTTOV-gb, has been validated against accurate and less time-efficient line-by-line radiative transfer models. In the frequency range commonly used for temperature and humidity profiling (22-60 GHz), root-mean-square brightness temperature differences are smaller than typical MWR uncertainties (˜ 0.5 K) at all channels used in this analysis. Brightness temperatures (TBs) computed with RTTOV-gb from radiosonde profiles have been compared with nearly simultaneous and co-located ground-based MWR observations. Differences between simulated and measured TBs are below 0.5 K for all channels except for the <span class="hlt">water</span> vapor band, where most of the uncertainty comes from instrumental errors. The Jacobians calculated with the K-module of RTTOV</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AMTD....5.8085M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AMTD....5.8085M"><span>Biases caused by the instrument bandwidth and beam width on simulated brightness temperature measurements from scanning <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meunier, V.; Löhnert, U.; Kollias, P.; Crewell, S.</p> <p>2012-11-01</p> <p>More so than the traditional fixed <span class="hlt">radiometers</span>, the scanning <span class="hlt">radiometer</span> requires a careful design to ensure high quality measurements. Here the impact of the <span class="hlt">radiometer</span> characteristics (e.g. antenna beam width, receiver bandwidth) and atmospheric propagation (e.g. curvature of the earth and refractivity) on the scanning <span class="hlt">radiometer</span> measurements are presented. A forward radiative transfer model that includes all these effects to represent the instrument measurements is used to estimate the biases as differences between the measurement with and without these characteristics for three commonly used frequency bands: K, V and W-band. The receiver channel bandwidth errors are not so important in K-band and W-band. Thus, the use of a wider bandwidth to improve detection at low signal-to-noise conditions is acceptable. The impact of the antenna beam width is higher than the receiver bandwidth, but, for V-band where they are of similar importance. Using simple regression algorithms, the effects of the bandwidth and beam width biases in liquid <span class="hlt">water</span> path, integrated <span class="hlt">water</span> vapor, and temperature are also examined. The largest errors in liquid <span class="hlt">water</span> path and integrated <span class="hlt">water</span> vapor are associated with the beam width errors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AMT.....6.1171M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AMT.....6.1171M"><span>Biases caused by the instrument bandwidth and beam width on simulated brightness temperature measurements from scanning <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meunier, V.; Löhnert, U.; Kollias, P.; Crewell, S.</p> <p>2013-05-01</p> <p>More so than the traditional fixed <span class="hlt">radiometers</span>, the scanning <span class="hlt">radiometer</span> requires a careful design to ensure high quality measurements. Here the impact of the <span class="hlt">radiometer</span> characteristics (e.g., antenna beam width and receiver bandwidth) and atmospheric propagation (e.g. curvature of the Earth and vertical gradient of refractive index) on scanning <span class="hlt">radiometer</span> measurements are presented. A forward radiative transfer model that includes all these effects to represent the instrument measurements is used to estimate the biases. These biases are estimated using differences between the measurement with and without these characteristics for three commonly used frequency bands: K, V and W-band. The receiver channel bandwidth errors are less important in K-band and W-band. Thus, the use of a wider bandwidth to improve detection at low signal-to-noise conditions is acceptable at these frequencies. The biases caused by omitting the antenna beam width in measurement simulations are larger than those caused by omitting the receiver bandwidth, except for V-band where the bandwidth may be more important in the vicinity of absorption peaks. Using simple regression algorithms, the effects of the bandwidth and beam width biases in liquid <span class="hlt">water</span> path, integrated <span class="hlt">water</span> vapour, and temperature are also examined. The largest errors in liquid <span class="hlt">water</span> path and integrated <span class="hlt">water</span> vapour are associated with the beam width errors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1073035','SCIGOV-DOEDE'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1073035"><span>ARM - Midlatitude Continental Convective Clouds <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Profiler (jensen-mwr)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Jensen, Mike</p> <p>2012-02-01</p> <p>A major component of the Mid-latitude Continental Convective Clouds Experiment (MC3E) field campaign was the deployment of an enhanced radiosonde array designed to capture the vertical profile of atmospheric state variables (pressure, temperature, humidity wind speed and wind direction) for the purpose of deriving the large-scale forcing for use in modeling studies. The radiosonde array included six sites (enhanced Central Facility [CF-1] plus five new sites) launching radiosondes at 3-6 hour sampling intervals. The network will cover an area of approximately (300)2 km2 with five outer sounding launch sites and one central launch location. The five outer sounding launch sites are: S01 Pratt, KS [ 37.7oN, 98.75oW]; S02 Chanute, KS [37.674, 95.488]; S03 Vici, Oklahoma [36.071, -99.204]; S04 Morris, Oklahoma [35.687, -95.856]; and S05 Purcell, Oklahoma [34.985, -97.522]. Soundings from the SGP Central Facility during MC3E can be retrieved from the regular ARM archive. During routine MC3E operations 4 radiosondes were launched from each of these sites (approx. 0130, 0730, 1330 and 1930 UTC). On days that were forecast to be convective up to four additional launches were launched at each site (approx. 0430, 1030, 1630, 2230 UTC). There were a total of approximately 14 of these high frequency launch days over the course of the experiment. These files contain brightness temperatures observed at Purcell during MC3E. The measurements were made with a 5 channel (22.235, 23.035, 23.835, 26.235, 30.000GHz) <span class="hlt">microwave</span> <span class="hlt">radiometer</span> at one minute intervals. The results have been separated into daily files and the day of observations is indicated in the file name. All observations were zenith pointing. Included in the files are the time variables base_time and time_offset. These follow the ARM time conventions. Base_time is the number seconds since January 1, 1970 at 00:00:00 for the first data point of the file and time_offset is the offset in seconds from base_time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AtmRe.163...36Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AtmRe.163...36Y"><span>Implementation of an orographic/nonorographic rainfall classification scheme in the GSMaP algorithm for <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamamoto, Munehisa K.; Shige, Shoichi</p> <p>2015-09-01</p> <p>We incorporate an orographic/nonorographic rainfall classification scheme into the Global Satellite Mapping of Precipitation algorithm for passive <span class="hlt">microwave</span> <span class="hlt">radiometers</span>. It improves rainfall estimation over the entire Asian region. However, low verification scores over the United States and Mexico result because vertical profiles of rainfall over the Sierra Madre Mountains are high even for orographic rainfall conditions. In this region, lightning activity is vigorous, with large amounts of solid particles such as graupels, occurring with strong convections. Hence, the orographic/nonorographic rainfall classification scheme is switched off for regions where strong lightning activity occurs in the rainfall type database. The revised zonal mean rainfall amounts obtained from the Tropical Rainfall Measuring Mission (TRMM) <span class="hlt">Microwave</span> Imager are now in better agreement with those from the version 7 of the TRMM Precipitation Radar over the United States and Mexico, as well as Asia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890005277','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890005277"><span>User's guide for the Nimbus 7 Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) CELL-ALL tape</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cu, C. C.; Han, D.; Kim, S. T.; Gloersen, P.</p> <p>1988-01-01</p> <p>The SMMR instrument onboard the Nimbus-7 satellite has been in operation since October 1978. It provided global coverage of passive <span class="hlt">microwave</span> observations at 6.6, 10.7, 18, 21, and 37 GHz. The oberved brightness temperature can be used to retrieve geophysical parameters, principally sea surface temperature, atmospheric <span class="hlt">water</span> vapor and liquid <span class="hlt">water</span> content over oceans, sea ice concentration, and snow cover over land. The SMME CELL-ALL Tape contains earth-located calibrated brightness temperature data which have been appropriately binned into cells of various grid sizes, allowing intercomparisons of observations made at different frequencies (with corresponding different footprint sizes). This user's guide describes the operation of the instrument, the flow of the data processing the calibration procedure, and the characteristics of the calibrated brightness temperatures and how they are binned. Detailed tape specifications and lists of available data are also provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810057663&hterms=Regime+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DRegime%2Bchange','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810057663&hterms=Regime+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DRegime%2Bchange"><span><span class="hlt">Microwave</span> <span class="hlt">radiometer</span> measurement of tidally induced salinity changes off the Georgia coast</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kendall, B. M.; Blanton, J. O.</p> <p>1981-01-01</p> <p>A quasi-synoptic survey of tidally induced salinity changes off the Georgia coast was performed by using a L band <span class="hlt">microwave</span> radiomater onboard a NASA aircraft. Salinity maps were obtained for ebb and flood conditions in order to define the salinity distributions near rivers and sounds and major changes that occur from ebb flow to flood flow. The Savannah River plume dominated the salinity regime and extended out from the Savannah River mouth about 12 km during ebb tidal conditions. The plume merged into a band of low salinity <span class="hlt">water</span> extending along the Georgia-South Carolina coast which was produced by the many river sources of freshwater entering the coastal <span class="hlt">waters</span>. The changes in salinity observed offshore of the river plume area were consistent with estimates of the changes that would occur over a typical tidal excursion perpendicular to the observed gradient.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950037378&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddmr','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950037378&hterms=dmr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddmr"><span>Cosmic temperature fluctuations from two years of COBE differential <span class="hlt">microwave</span> <span class="hlt">radiometers</span> observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bennett, C. L.; Kogut, A.; Hinshaw, G.; Banday, A. J.; Wright, E. L.; Gorski, K. M.; Wilkinson, D. T.; Weiss, R.; Smoot, G. F.; Meyer, S. S.</p> <p>1994-01-01</p> <p>The first two years of Cosmic Background Explorer (COBE) Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> (DMR) observations of the cosmic <span class="hlt">microwave</span> background (CMB) anisotropy are analyzed and compared with our previously published first year results. The results are consistent, but the addition of the second year of data increases the precision and accuracy detected CMB temperature fluctuations. The 2 yr 53 GHz data are characterized by rms temperature fluctuations of (delta-T)(sub rms) (7 deg) = 44 +/- 7 micro-K and (delta-T)(sub rms) (10 deg) = 30.5 +/- 2.7 micro-K at 7 deg and 10 deg angular resolution, respectively. The 53 x 90 GHz cross-correlation amplitude at zero lag is C(0)(sup 1/2) = 36 +/- 5 micro-K (68% CL) for the unsmoothed (7 deg resolution) DMR data. We perform a likelihood analysis of the cross-correlation function, with Monte Carlo simulations to infer biases of the method, for a power-law model of initial density fluctuations, P(k) proportional to R(exp n). The Monte Carlo simulations indicate that derived estimates of n are biased by +0.11 +/- 0.01, while the subset of simulations with a low quadrupole (as observed) indicate a bias of +0.31+/- 0.04. Derived values for 68% confidence intervals are given corrected (and not corrected) for our estimated biases. Including the quadrupole anisotropy, the most likely quadrupole-normalized amplitude is Q(sub rms-PS) = 14.3(sup + 5.2 sub -3.3) micro-K (12.8(sup + 5.2 sub -3.3) micro-K0 with a spectral index n = 1.42(sup + 0.49 sub -0.55)(n = 1.53(sup + 0.49 sub -0.55). With n fixed to 1.0 the most likely amplitude is 18.2 +/- 11.5 micro-K (17.4 +/- 1.5 micro-K). The marginal likelihood of n is 1.42 +/- 0.37 (1.53 +/- 0.37). Excluding the quadrupole anisotropy, the most likely quadrupole-normalized amplitude is Q(sub rms-PS) = 17.4(sup + 7.5 sub -5.2) micro-K (15.8(sup + 7.5 sub -5.2) micro-K) with a spectral index n = 1.11(sup + 0.60 sub -0.55) (n = 1.22(sup + 0.60 sub -0.55). With n fixed to 1.0 the most likely</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994ApJ...436..423B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994ApJ...436..423B"><span>Cosmic temperature fluctuations from two years of COBE differential <span class="hlt">microwave</span> <span class="hlt">radiometers</span> observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bennett, C. L.; Kogut, A.; Hinshaw, G.; Banday, A. J.; Wright, E. L.; Gorski, K. M.; Wilkinson, D. T.; Weiss, R.; Smoot, G. F.; Meyer, S. S.; Mather, J. C.; Lubin, P.; Loewenstein, K.; Lineweaver, C.; Keegstra, P.; Kaita, E.; Jackson, P. D.; Cheng, E. S.</p> <p>1994-12-01</p> <p>The first two years of Cosmic Background Explorer (COBE) Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometers</span> (DMR) observations of the cosmic <span class="hlt">microwave</span> background (CMB) anisotropy are analyzed and compared with our previously published first year results. The results are consistent, but the addition of the second year of data increases the precision and accuracy detected CMB temperature fluctuations. The 2 yr 53 GHz data are characterized by rms temperature fluctuations of (delta-T)rms (7 deg) = 44 +/- 7 micro-K and (delta-T)rms (10 deg) = 30.5 +/- 2.7 micro-K at 7 deg and 10 deg angular resolution, respectively. The 53 x 90 GHz cross-correlation amplitude at zero lag is C(0)1/2 = 36 +/- 5 micro-K (68% CL) for the unsmoothed (7 deg resolution) DMR data. We perform a likelihood analysis of the cross-correlation function, with Monte Carlo simulations to infer biases of the method, for a power-law model of initial density fluctuations, P(k) proportional to Rn. The Monte Carlo simulations indicate that derived estimates of n are biased by +0.11 +/- 0.01, while the subset of simulations with a low quadrupole (as observed) indicate a bias of +0.31+/- 0.04. Derived values for 68% confidence intervals are given corrected (and not corrected) for our estimated biases. Including the quadrupole anisotropy, the most likely quadrupole-normalized amplitude is Qrms-PS = 14.3+5.2-3.3 micro-K (12.8+5.2-3.3 micro-K0 with a spectral index n = 1.42+0.49-0.55 (n = 1.53+0.49-0.55. With n fixed to 1.0 the most likely amplitude is 18.2 +/- 11.5 micro-K (17.4 +/- 1.5 micro-K). The marginal likelihood of n is 1.42 +/- 0.37 (1.53 +/- 0.37). Excluding the quadrupole anisotropy, the most likely quadrupole-normalized amplitude is Qrms-PS = 17.4+7.5-5.2 micro-K (15.8+7.5-5.2 micro-K) with a spectral index n = 1.11+0.60-0.55 (n = 1.22+0.60-0.55. With n fixed to 1.0 the most likely amplitude is 18.6 +/- 1.6 micro-K (18.2 +/- 1.6 micro-K). The marginal likelihood of n is 1.11 +/- 0.40 (1.22 +/- 0.40). Our best</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995JGR...10025469W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995JGR...10025469W"><span>Some features observed by the L-band push broom <span class="hlt">microwave</span> <span class="hlt">radiometer</span> over the Konza Prairie during 1985-1989</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, J. R.</p> <p>1995-12-01</p> <p>Airborne L-band radiometric measurements were conducted over the Konza Prairie near Manhattan, Kansas, in the summers of 1985, 1987, 1988, and 1989 to study the relationship among surface <span class="hlt">microwave</span> emission, soil moisture, and vegetation cover. The annual surface treatments that were applied to the watersheds in the experimental area appeared to show a significant impact on the surface <span class="hlt">microwave</span> emission. A watershed that was burned every year showed a better sensitivity to soil moisture variation than those burned less frequently. This feature persisted even though the radiometric measurements were made over those watersheds that were burned in the same year. It was concluded that the burning process might not completely remove a thatch layer of efficient <span class="hlt">microwave</span> absorption, which was developed through years of accumulation of senescent vegetation. Results from the analysis of these radiometric data sets also suggest the need of an adequate estimation of vegetation biomass in order to obtain a reliable retrieval of surface soil moisture from L-band radiometric measurements. On the basis of the data acquired from the 1987 and 1989 field campaigns, the push broom <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (PBMR) measurements are likely to give errors of the order of ±0.065 g/cm3 in surface soil moisture estimation if there are no measurements of vegetation biomass. Measurements of vegetation biomass to an accuracy of ±0.46 kg/m2 improve the corresponding PBMR estimation of surface soil moisture to an accuracy of ±0.032 g/cm3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740002268','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740002268"><span><span class="hlt">Microwave</span> signatures of snow and fresh <span class="hlt">water</span> ice</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmugge, T.; Wilheit, T. T.; Gloersen, P.; Meier, M. F.; Frank, D.; Dirmhirn, I.</p> <p>1973-01-01</p> <p>During March of 1971, the NASA Convair 990 Airborne Observatory carrying <span class="hlt">microwave</span> <span class="hlt">radiometers</span> in the wavelength range 0.8 to 21 cm was flown over dry snow with different substrata: Lake ice at Bear Lake in Utah; wet soil in the Yampa River Valley near Steamboat Springs, Colorado; and glacier ice, firm and wet snow on the South Cascade Glacier in Washington. The data presented indicate that the transparency of the snow cover is a function of wavelength. False-color images of <span class="hlt">microwave</span> brightness temperatures obtained from a scanning <span class="hlt">radiometer</span> operating at a wavelength of 1.55 cm demonstrate the capability of scanning <span class="hlt">radiometers</span> for mapping snowfields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7601N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7601N"><span>Comparison of stratospheric temperature profiles from a ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> with lidar, radiosonde and satellite data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Navas-Guzmán, Francisco; Kämpfer, Niklaus; Haefele, Alexander; Keckhut, Philippe; Hauchecorne, Alain</p> <p>2015-04-01</p> <p>The importance of the knowledge of the temperature structure in the atmosphere has been widely recognized. Temperature is a key parameter for dynamical, chemical and radiative processes in the atmosphere. The cooling of the stratosphere is an indicator for climate change as it provides evidence of natural and anthropogenic climate forcing just like surface warming ( [1] and references therein). However, our understanding of the observed stratospheric temperature trend and our ability to test simulations of the stratospheric response to emissions of greenhouse gases and ozone depleting substances remains limited. Stratospheric long-term datasets are sparse and obtained trends differ from one another [1]. Therefore it is important that in the future such datasets are generated. Different techniques allow to measure stratospheric temperature profiles as radiosonde, lidar or satellite. The main advantage of <span class="hlt">microwave</span> <span class="hlt">radiometers</span> against these other instruments is a high temporal resolution with a reasonable good spatial resolution. Moreover, the measurement at a fixed location allows to observe local atmospheric dynamics over a long time period, which is crucial for climate research. TEMPERA (TEMPERature <span class="hlt">RAdiometer</span>) is a newly developed ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> designed, built and operated at the University of Bern. The instrument and the retrieval of temperature profiles has been described in detail in [2]. TEMPERA is measuring a pressure broadened oxygen line at 53.1 GHz in order to determine stratospheric temperature profiles. The retrieved profiles of TEMPERA cover an altitude range of approximately 20 to 45 km with a vertical resolution in the order of 15 km. The lower limit is given by the instrumental baseline and the bandwidth of the measured spectrum. The upper limit is given by the fact that above 50 km the oxygen lines are splitted by the Zeeman effect in the terrestrial magnetic field. In this study we present a comparison of stratospheric</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870027821&hterms=quantitative+Content+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dquantitative%2BContent%2Banalysis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870027821&hterms=quantitative+Content+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dquantitative%2BContent%2Banalysis"><span>Retrieving cloud ice <span class="hlt">water</span> content and geometrical thickness from <span class="hlt">microwave</span> and infrared radiometric observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wu, M.-L. C.</p> <p>1986-01-01</p> <p>Techniques are presented and their application illustrated for analysis of remotely sensed data collected with an aircraft carrying a multispectral cloud <span class="hlt">radiometer</span> and an advanced <span class="hlt">microwave</span> moisture sounder. The instruments were used on NASA high altitude flights to perform cloud field experiments. Sample IR and <span class="hlt">microwave</span> brightness temperature data are provided as functions of the ice <span class="hlt">water</span> path and of the ice <span class="hlt">water</span> content. Quantitative models are described for deriving the cloud ice (or liquid) <span class="hlt">water</span> content and the cloud geometric thickness from the radiometric data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810037406&hterms=properties+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dproperties%2Bwater','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810037406&hterms=properties+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dproperties%2Bwater"><span>Measurement of dielectric properties and determination of <span class="hlt">microwave</span> emissivity of polluted <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Blume, H.-J. C.</p> <p>1980-01-01</p> <p>The dielectric properties of polluted <span class="hlt">waters</span> are measured with a reflection-type resonant cavity at 1.43 GHz. Very small <span class="hlt">water</span> samples in quartz tubes of known volume are placed in the center of the maximum electric field. Measurement of the resonance-frequency variation and a change of the cavity's quality factor are used to determine the dielectric properties. The <span class="hlt">microwave</span> emissivity of the polluted <span class="hlt">water</span> is then calculated via the Fresnel equation and applied to data reductions of <span class="hlt">microwave</span> <span class="hlt">radiometer</span> measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870003663&hterms=working+conditions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dworking%2Bconditions','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870003663&hterms=working+conditions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dworking%2Bconditions"><span>First meeting of the Working Group on the Shuttle <span class="hlt">Microwave</span> Precipitation <span class="hlt">Radiometer</span> (SMPR)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1985-01-01</p> <p>The working group agreed that the first (primary) objective should be the determination of methods for the accurate measurement of total rain <span class="hlt">water</span> and total cloud <span class="hlt">water</span> with passive <span class="hlt">microwave</span> methods. There was no argument on the points concerning nonlinear relationships between T sub B and rain rate (R) over the range of important rain rates (half of oceanic rainfall occurs at rates greater than 15 mm h-1), such that variations in rain rate within a footprint lead to an incorrect measurement of the average rate for that footprint, and one cannot determine the characteristics of the sensed rain area. This is especially true near 18 GHz, where the dynamic range above 15 mm h-1 is very small because this frequency does not clearly fall in either a scattering regime or emissive regime at these wavelengths. It is also not clear whether very low frequency (emissive) techniques will be the best at measuring rain processes, or high frequency (scattering) techniques, where precipitation-size ice plays a major role in the signal attenuation. It is still not known what signal of rain is at certain rates on an observational basis because of the many different conditions that can exist within a single satellite observed footprint.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6172D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6172D"><span>RTTOV-gb - Adapting the fast radiative transfer model RTTOV for the assimilation of ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Angelis, Francesco; Cimini, Domenico; Hocking, James; Martinet, Pauline; Kneifel, Stefan</p> <p>2016-04-01</p> <p>The Planetary Boundary Layer (PBL) is the single most important under-sampled part of the atmosphere. According to the WMO Statement Of Guidance For Global Numerical Weather Prediction (NWP), temperature and humidity profiles (in cloudy areas) are among the four critical atmospheric variables not adequately measured in the PBL. Ground-based <span class="hlt">microwave</span> <span class="hlt">radiometers</span> (MWR) provide temperature and humidity profiles in both clear- and cloudy-sky conditions with high temporal resolution and low-to-moderate vertical resolution, with information mostly residing in the PBL. Ground-based MWR offer to bridge this observational gap by providing continuous temperature and humidity information in the PBL. The MWR data assimilation into NWP models may be particularly important in nowcasting and severe weather initiation. The assimilation of thermodynamic profiles retrieved from MWR data has been recently experimented, but a way to possibly increase the impact is to directly assimilate measured radiances instead of retrieved profiles. The assimilation of observed radiances in a variational scheme requires the following tools: (i) a fast radiative transfer (RT) model to compute the simulated radiances at MWR channels from the NWP model fields (ii) the partial derivatives (Jacobians) of the fast radiative transfer model with respect to control variables to optimize the distances of the atmospheric state from both the first guess and the observations. Such a RT model is available from the EUMETSAT NWPSAF (Numerical Weather Prediction Satellite Application Facility) and well accepted in the NWP community: RTTOV. This model was developed for nadir-viewing passive visible, infrared, and <span class="hlt">microwave</span> satellite <span class="hlt">radiometers</span>, spectrometers and interferometers. It has been modified to handle ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> observations. This version of RTTOV, called RTTOV-gb, provides the tools needed to exploit ground-based upward looking MWR brightness temperatures into NWP variational data</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100031300&hterms=dawson&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Ddawson','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100031300&hterms=dawson&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Ddawson"><span><span class="hlt">Radiometer</span> Testbed Development for SWOT</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kangaslahti, Pekka; Brown, Shannon; Gaier, Todd; Dawson, Douglas; Harding, Dennis; Fu, Lee-Lueng; Esteban-Fernandez, Daniel</p> <p>2010-01-01</p> <p>Conventional altimeters include nadir looking colocated 18-37 GHz <span class="hlt">microwave</span> <span class="hlt">radiometer</span> to measure wet tropospheric path delay. These have reduced accuracy in coastal zone (within 50 km from land) and do not provide wet path delay over land. The addition of high frequency channels to Jason-class <span class="hlt">radiometer</span> will improve retrievals in coastal regions and enable retrievals over land. High-frequency window channels, 90, 130 and 166 GHz are optimum for improving performance in coastal region and channels on 183 GHz <span class="hlt">water</span> vapor line are ideal for over-land retrievals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100031300&hterms=dennis+dawson&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Ddennis%2Bdawson','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100031300&hterms=dennis+dawson&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Ddennis%2Bdawson"><span><span class="hlt">Radiometer</span> Testbed Development for SWOT</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kangaslahti, Pekka; Brown, Shannon; Gaier, Todd; Dawson, Douglas; Harding, Dennis; Fu, Lee-Lueng; Esteban-Fernandez, Daniel</p> <p>2010-01-01</p> <p>Conventional altimeters include nadir looking colocated 18-37 GHz <span class="hlt">microwave</span> <span class="hlt">radiometer</span> to measure wet tropospheric path delay. These have reduced accuracy in coastal zone (within 50 km from land) and do not provide wet path delay over land. The addition of high frequency channels to Jason-class <span class="hlt">radiometer</span> will improve retrievals in coastal regions and enable retrievals over land. High-frequency window channels, 90, 130 and 166 GHz are optimum for improving performance in coastal region and channels on 183 GHz <span class="hlt">water</span> vapor line are ideal for over-land retrievals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.9344C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.9344C"><span>Assimilation of humidity and temperature observations retrieved from ground-based <span class="hlt">microwave</span> <span class="hlt">radiometers</span> into a convective-scale NWP model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caumont, Olivier; Vincendon, Béatrice; Cimini, Domenico; Löhnert, Ulrich; Alados-Arboledas, Lucas; Bleisch, René; Buffa, Franco; Enrico Ferrario, Massimo; Haefele, Alexander; Huet, Thierry; Madonna, Fabio; Pace, Giandomenico</p> <p>2016-04-01</p> <p>Temperature and humidity retrievals from an international network of ground-based <span class="hlt">microwave</span> <span class="hlt">radiometers</span> (MWR) have been collected to assess the potential of their assimilation into a convective-scale Numerical Weather Prediction (NWP) system. Thirteen stations over a domain encompassing the western Mediterranean basin were considered for a time period of forty-one days in autumn, when heavy-precipitation events most often plague this area. Prior to their assimilation, MWR data were compared to very-short-term forecasts. Observation-minus-background statistics revealed some biases, but standard deviations were comparable to that obtained with radiosondes. The MWR data were then assimilated in a three-dimensional variational (3DVar) data assimilation system through the use of a rapid update cycle. A set of sensitivity experiments allowed assessing extensively the impact of the assimilation of temperature and humidity profiles, both separately and jointly. The respective benefit of MWR data and radiosonde data on analyses and forecasts was also investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6747450','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6747450"><span>Retrieval of ocean surface parameters from the scanning multifrequency <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (SMMR) on the Nimbus-7 satellite</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wilheit, T.T.; Chang, E.; Gatlin, J.; Greaves, J.; Han, D.; Krupp, B.M.; Milman, A.S.</p> <p>1984-03-01</p> <p>Sea-surface temperature retrievals have been tested on 2 months of Nimbus-7 scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data. Using the prelaunch versions of the instrument calibration and geophysical parameter retrieval algorithms the initial results were poor. Improved algorithms produced substantially better results. It appears that at least for the night-Southern Hemisphere portion of the Nimbus-7 orbit, a rms measurement accuracy of 1.45/sup 0/C has been achieved. Similar tests with wind speed retrievals yield an accuracy of 2.7 m/s rms with no substantial differences between day and night measurements but limited by availability of surface observations to the Northern Hemisphere. Moreover, it appears that the retrieved wind speed is more nearly related to the square of the wind observed at the surface than to the wind itself.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17272186','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17272186"><span>Five-band <span class="hlt">microwave</span> <span class="hlt">radiometer</span> system for non-invasive measurement of brain temperature in new-born infants: system calibration and its feasibility.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sugiura, T; Kouno, Y; Hashizume, A; Hirata, H; Hand, J W; Okita, Y; Mizushina, S</p> <p>2004-01-01</p> <p>Recent simulation studies have shown that a technique of multi-frequency <span class="hlt">microwave</span> radiometry is feasible for non-invasive measurement of deep brain temperatures in the new-born infants. A five-band <span class="hlt">microwave</span> <span class="hlt">radiometer</span> system has been developed, and its operation in a normal electromagnetic environment is checked. Five receivers operating with a waveguide antenna and at center frequencies of 1.2, 1.65, 2.3, 3.0 and 3.6 GHz (0.4 GHz bandwidth) are calibrated using a temperature-controlled <span class="hlt">water</span>-bath. Temperature resolutions obtained for each receiver are 0.183, 0.273, 0.148, 0.108 and 0.118 K, respectively. A temperature retrieval simulation based on these resolutions and the previously proposed algorithm shows that the confidence interval, as produced by thermal noise, is 0.62 K for the retrieved central brain temperature. If the conductivity of brain is estimated wrong by 10 %, this will result in an error of 0.3-0.4 K. The result of this work is encouraging for realization of radiometric measurement of temperature profile in a baby's head.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840061353&hterms=corn&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dcorn','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840061353&hterms=corn&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dcorn"><span>Effects of corn stalk orientation and <span class="hlt">water</span> content on passive <span class="hlt">microwave</span> sensing of soil moisture</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oneill, P. E.; Blanchard, B. J.; Wang, J. R.; Gould, W. I.; Jackson, T. J.</p> <p>1984-01-01</p> <p>A field experiment was conducted utilizing artificial arrangements of plant components during the summer of 1982 to examine the effects of corn canopy structure and plant <span class="hlt">water</span> content on <span class="hlt">microwave</span> emission. Truck-mounted <span class="hlt">microwave</span> <span class="hlt">radiometers</span> at C (5 GHz) and L (1.4 GHz) band sensed vertically and horizontally polarized radiation concurrent with ground observations of soil moisture and vegetation parameters. Results indicate that the orientation of cut stalks and the distribution of their dielectric properties through the canopy layer can influence the <span class="hlt">microwave</span> emission measured from a vegetation/soil scene. The magnitude of this effect varies with polarization and frequency and with the amount of <span class="hlt">water</span> in the plant, disappearing at low levels of vegetation <span class="hlt">water</span> content. Although many of the canopy structures and orientations studied in this experiment are somewhat artificial, they serve to improve understanding of <span class="hlt">microwave</span> energy interactions within a vegetation canopy and to aid in the development of appropriate physically based vegetation models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840061353&hterms=Corn&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DCorn','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840061353&hterms=Corn&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DCorn"><span>Effects of corn stalk orientation and <span class="hlt">water</span> content on passive <span class="hlt">microwave</span> sensing of soil moisture</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oneill, P. E.; Blanchard, B. J.; Wang, J. R.; Gould, W. I.; Jackson, T. J.</p> <p>1984-01-01</p> <p>A field experiment was conducted utilizing artificial arrangements of plant components during the summer of 1982 to examine the effects of corn canopy structure and plant <span class="hlt">water</span> content on <span class="hlt">microwave</span> emission. Truck-mounted <span class="hlt">microwave</span> <span class="hlt">radiometers</span> at C (5 GHz) and L (1.4 GHz) band sensed vertically and horizontally polarized radiation concurrent with ground observations of soil moisture and vegetation parameters. Results indicate that the orientation of cut stalks and the distribution of their dielectric properties through the canopy layer can influence the <span class="hlt">microwave</span> emission measured from a vegetation/soil scene. The magnitude of this effect varies with polarization and frequency and with the amount of <span class="hlt">water</span> in the plant, disappearing at low levels of vegetation <span class="hlt">water</span> content. Although many of the canopy structures and orientations studied in this experiment are somewhat artificial, they serve to improve understanding of <span class="hlt">microwave</span> energy interactions within a vegetation canopy and to aid in the development of appropriate physically based vegetation models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040021408&hterms=temperature+body+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dtemperature%2Bbody%2Bwater','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040021408&hterms=temperature+body+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dtemperature%2Bbody%2Bwater"><span>Radiant Temperature Nulling <span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2002-01-01</p> <p>A nulling, self-calibrating infrared <span class="hlt">radiometer</span> is being developed for use in noncontact measurement of temperature in any of a variety of industrial and scientific applications. This instrument is expected to be especially well-suited to measurement of ambient or near-ambient temperature and, even more specifically, for measuring the surface temperature of a natural body of <span class="hlt">water</span>. Although this <span class="hlt">radiometer</span> would utilize the long-wavelength infrared (LWIR) portion of the spectrum (wavelengths of 8 to 12 m), its basic principle of operation could also be applied to other spectral bands (corresponding to other temperature ranges) in which the atmosphere is transparent and in which design requirements for sensitivity and temperature-measurement accuracy could be satisfied. The underlying principle of nulling and self-calibration is the same as that of a typical <span class="hlt">microwave</span> <span class="hlt">radiometer</span>, but because of differences between the characteristics of signals in the infrared and <span class="hlt">microwave</span> spectral regions, the principle must be implemented in a different way. A detailed description of the instrument including an infrared photodetector equipped with focusing input optics [e.g., lens(es) and/or mirrors] and an input LWIR band-pass filter is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880003302','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880003302"><span>Non-linearity in measurement systems: Evaluation method and application to <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stelzried, C. T.</p> <p>1987-01-01</p> <p>A simple method for determination and correction of nonlinaearity in measurement systems is presented. The technique is applicable to a wide range of measuring systems. The basic concept, an analysis, and a sample application are given. Nonlinearity of the Goldstone DSS 13 low noise HEMT 2.3 GHz (S-band) <span class="hlt">radiometer</span> system results in noise temperature measurement errors. These errors are successfully correct with this method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040021337&hterms=steven+johnson&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsteven%2Bjohnson','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040021337&hterms=steven+johnson&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsteven%2Bjohnson"><span>Design of an L-Band <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> with Active Mitigation of Interference</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ellingson, Steven W.; Hampson, G. A.; Johnson, J. T.</p> <p>2003-01-01</p> <p>For increased sensitivity in L-band radiometry, bandwidths on the order of 100 MHz are desirable. This will likely require active countermeasures to mitigate RFI. In this paper, we describe a new <span class="hlt">radiometer</span> which coherently samples 100 MHz of spectrum and applies real-time RFI mitigation techniques using FPGAs. A field test of an interim version of this design in a radio astronomy observation corrupted by radar pulses is described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22163943','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22163943"><span>A general analysis of the impact of digitization in <span class="hlt">microwave</span> correlation <span class="hlt">radiometers</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bosch-Lluis, Xavier; Ramos-Perez, Isaac; Camps, Adriano; Rodriguez-Alvarez, Nereida; Valencia, Enric; Park, Hyuk</p> <p>2011-01-01</p> <p>This study provides a general framework to analyze the effects on correlation <span class="hlt">radiometers</span> of a generic quantization scheme and sampling process. It reviews, unifies and expands several previous works that focused on these effects separately. In addition, it provides a general theoretical background that allows analyzing any digitization scheme including any number of quantization levels, irregular quantization steps, gain compression, clipping, jitter and skew effects of the sampling period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Metro..51S.282S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Metro..51S.282S"><span>Spectral irradiance measurement and actinic <span class="hlt">radiometer</span> calibration for UV <span class="hlt">water</span> disinfection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sperfeld, Peter; Barton, Bettina; Pape, Sven; Towara, Anna-Lena; Eggers, Jutta; Hopfenmüller, Gabriel</p> <p>2014-12-01</p> <p>In a joint project, sglux and PTB investigated and developed methods and equipment to measure the spectral and weighted irradiance of high-efficiency UV-C emitters used in <span class="hlt">water</span> disinfection plants. A calibration facility was set up to calibrate the microbicidal irradiance responsivity of actinic <span class="hlt">radiometers</span> with respect to the weighted spectral irradiance of specially selected low-pressure mercury and medium-pressure mercury UV lamps. To verify the calibration method and to perform on-site tests, spectral measurements were carried out directly at <span class="hlt">water</span> disinfection plants in operation. The weighted microbicidal irradiance of the plants was calculated and compared to the measurements of various actinic <span class="hlt">radiometers</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930009336','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930009336"><span>Botswana <span class="hlt">water</span> and surface energy balance research program. Part 2: Large scale moisture and passive <span class="hlt">microwaves</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vandegriend, A. A.; Owe, M.; Chang, A. T. C.</p> <p>1992-01-01</p> <p>The Botswana <span class="hlt">water</span> and surface energy balance research program was developed to study and evaluate the integrated use of multispectral satellite remote sensing for monitoring the hydrological status of the Earth's surface. The research program consisted of two major, mutually related components: a surface energy balance modeling component, built around an extensive field campaign; and a passive <span class="hlt">microwave</span> research component which consisted of a retrospective study of large scale moisture conditions and Nimbus scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> <span class="hlt">microwave</span> signatures. The integrated approach of both components are explained in general and activities performed within the passive <span class="hlt">microwave</span> research component are summarized. The <span class="hlt">microwave</span> theory is discussed taking into account: soil dielectric constant, emissivity, soil roughness effects, vegetation effects, optical depth, single scattering albedo, and wavelength effects. The study site is described. The soil moisture data and its processing are considered. The relation between observed large scale soil moisture and normalized brightness temperatures is discussed. Vegetation characteristics and inverse modeling of soil emissivity is considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950023830','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950023830"><span>Emissivity measurements in thin metallized membrane reflectors used for <span class="hlt">microwave</span> <span class="hlt">radiometer</span> sensors</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schroeder, Lyle C.; Cravey, Robin L.; Scherner, Michael J.; Hearn, Chase P.; Blume, Hans-Juergen C.</p> <p>1995-01-01</p> <p>This paper is concerned with electromagnetic losses in metallized films used for inflatable reflectors. An inflatable membrane is made of tough elastic material such as Kapton, and it is not electromagnetically reflective by design. A film of conducting metal is added to the membrane to enhance its reflective properties. Since the impetus for use of inflatables for spacecraft is the light weight and compact packaging, it is important that the metal film be as thin as possible. However, if the material is not conductive or thick enough, the radiation due to the emissivity of the reflector could be a significant part of the radiation gathered by the <span class="hlt">radiometer</span>. The emissivity would be of little consequence to a radar or solar collector; but for a <span class="hlt">radiometer</span> whose signal is composed of thermal radiation, this contribution could be severe. Bulk properties of the metal film cannot be used to predict its loss. For this reason, a program of analysis and measurement was undertaken to determine the emissivities of a number of candidate metallized film reflectors. This paper describes the three types of measurements which were performed on the metallized thin films: (1) a network analyzer system with an L-band waveguide; (2) an S-band <span class="hlt">radiometer</span>; and (3) a network analyzer system with a C-band antenna free-space transmission system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910009245','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910009245"><span>Atmospheric <span class="hlt">water</span> parameters in mid-latitude cyclones observed by <span class="hlt">microwave</span> radiometry and compared to model calculations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Katsaros, Kristina B.; Hammarstrand, Ulla; Petty, Grant W.</p> <p>1990-01-01</p> <p>Existing and experimental algorithms for various parameters of atmospheric <span class="hlt">water</span> content such as integrated <span class="hlt">water</span> vapor, cloud <span class="hlt">water</span>, precipitation, are used to examine the distribution of these quantities in mid latitude cyclones. The data was obtained from signals given by the special sensor <span class="hlt">microwave</span>/imager (SSM/I) and compared with data from the nimbus scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (SMMR) for North Atlantic cyclones. The potential of <span class="hlt">microwave</span> remote sensing for enhancing knowledge of the horizontal structure of these storms and to aid the development and testing of the cloud and precipitation aspects of limited area numerical models of cyclonic storms is investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20130000263&hterms=Earth+Science&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DEarth%2BScience','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20130000263&hterms=Earth+Science&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DEarth%2BScience"><span>CHARM: A CubeSat <span class="hlt">Water</span> Vapor <span class="hlt">Radiometer</span> for Earth Science</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lim, Boon; Mauro, David; DeRosee, Rodolphe; Sorgenfrei, Matthew; Vance, Steve</p> <p>2012-01-01</p> <p>The Jet Propulsion Laboratory (JPL) and Ames Research Center (ARC) are partnering in the CubeSat Hydrometric Atmospheric <span class="hlt">Radiometer</span> Mission (CHARM), a <span class="hlt">water</span> vapor <span class="hlt">radiometer</span> integrated on a 3U CubeSat platform, selected for implementation under NASA Hands-On Project Experience (HOPE-3). CHARM will measure 4 channels at 183 GHz <span class="hlt">water</span> vapor line, subsets of measurements currently performed by larger and more costly spacecraft (e.g. ATMS, AMSU-B and SSMI/S). While flying a payload that supports SMD science objectives, CHARM provides a hands-on opportunity to develop technical, leadership, and project skills. CHARM will furthermore advance the technology readiness level (TRL) of the 183 GHz receiver subsystem from TRL 4 to TRL 6 and the CubeSat 183 GHz <span class="hlt">radiometer</span> system from TRL 4 to TRL 7.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20130000263&hterms=water+science+technology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwater%2Bscience%2Btechnology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20130000263&hterms=water+science+technology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwater%2Bscience%2Btechnology"><span>CHARM: A CubeSat <span class="hlt">Water</span> Vapor <span class="hlt">Radiometer</span> for Earth Science</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lim, Boon; Mauro, David; DeRosee, Rodolphe; Sorgenfrei, Matthew; Vance, Steve</p> <p>2012-01-01</p> <p>The Jet Propulsion Laboratory (JPL) and Ames Research Center (ARC) are partnering in the CubeSat Hydrometric Atmospheric <span class="hlt">Radiometer</span> Mission (CHARM), a <span class="hlt">water</span> vapor <span class="hlt">radiometer</span> integrated on a 3U CubeSat platform, selected for implementation under NASA Hands-On Project Experience (HOPE-3). CHARM will measure 4 channels at 183 GHz <span class="hlt">water</span> vapor line, subsets of measurements currently performed by larger and more costly spacecraft (e.g. ATMS, AMSU-B and SSMI/S). While flying a payload that supports SMD science objectives, CHARM provides a hands-on opportunity to develop technical, leadership, and project skills. CHARM will furthermore advance the technology readiness level (TRL) of the 183 GHz receiver subsystem from TRL 4 to TRL 6 and the CubeSat 183 GHz <span class="hlt">radiometer</span> system from TRL 4 to TRL 7.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983JApMe..22..779W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983JApMe..22..779W"><span>Profiling Atmospheric <span class="hlt">Water</span> Vapor by <span class="hlt">Microwave</span> Radiometry.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, J. R.; King, J. L.; Wilheit, T. T.; Szejwach, G.; Gesell, L. H.; Nieman, R. A.; Niver, D. S.; Krupp, B. M.; Gagliano, J. A.</p> <p>1983-05-01</p> <p>High-altitude <span class="hlt">microwave</span> radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric <span class="hlt">water</span> vapor profiles over both land and <span class="hlt">water</span>. An algorithm based on an extended Kaiman-Bucy filter was implemented and applied for the <span class="hlt">water</span> vapor retrieval. The results show great promise in atmospheric <span class="hlt">water</span> vapor profiling by <span class="hlt">microwave</span> radiometry heretofore not attainable at lower frequencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830058657&hterms=GESELL&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGESELL','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830058657&hterms=GESELL&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGESELL"><span>Profiling atmospheric <span class="hlt">water</span> vapor by <span class="hlt">microwave</span> radiometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, J. R.; Wilheit, T. T.; Szejwach, G.; Gesell, L. H.; Nieman, R. A.; Niver, D. S.; Krupp, B. M.; Gagliano, J. A.; King, J. L.</p> <p>1983-01-01</p> <p>High-altitude <span class="hlt">microwave</span> radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric <span class="hlt">water</span> vapor profiles over both land and <span class="hlt">water</span>. An algorithm based on an extended kalman-Bucy filter was implemented and applied for the <span class="hlt">water</span> vapor retrieval. The results show great promise in atmospheric <span class="hlt">water</span> vapor profiling by <span class="hlt">microwave</span> radiometry heretofore not attainable at lower frequencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830058657&hterms=water+filter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwater%2Bfilter','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830058657&hterms=water+filter&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwater%2Bfilter"><span>Profiling atmospheric <span class="hlt">water</span> vapor by <span class="hlt">microwave</span> radiometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, J. R.; Wilheit, T. T.; Szejwach, G.; Gesell, L. H.; Nieman, R. A.; Niver, D. S.; Krupp, B. M.; Gagliano, J. A.; King, J. L.</p> <p>1983-01-01</p> <p>High-altitude <span class="hlt">microwave</span> radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric <span class="hlt">water</span> vapor profiles over both land and <span class="hlt">water</span>. An algorithm based on an extended kalman-Bucy filter was implemented and applied for the <span class="hlt">water</span> vapor retrieval. The results show great promise in atmospheric <span class="hlt">water</span> vapor profiling by <span class="hlt">microwave</span> radiometry heretofore not attainable at lower frequencies.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912683R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912683R"><span>Retrieval of cloud and drizzle microphysical properties using ground-based radar, lidar, and <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rusli, Stephanie; Donovan, David; Russchenberg, Herman</p> <p>2017-04-01</p> <p>Owing to their large aerial extent, low-level liquid <span class="hlt">water</span> clouds have a strong impact on the Earth's energy balance. Observations of these clouds to characterize the microphysical and radiative processes are therefore needed for climate studies. In such clouds, drizzle is recognized to be a common occurence and an accurate retrieval of the cloud physical properties has to account for its possible presence. We develop a retrieval technique that exploits the synergy of different remote sensing systems to simultaneously profile the cloud and drizzle properties using ground-based measurements of radar reflectivity, lidar attenuated backscatter and <span class="hlt">microwave</span> brightness temperatures. This technique first identifies the presence of drizzle above the cloud base in an optimized and a physically-consistent manner. Subsequently, physical forward models, coupled to cloud and drizzle structure parametrization are used in an optimal-estimation type framework to derive the best-estimate for the cloud and drizzle properties as a function of height. The cloud retrieval is evaluated using simulated signals generated from large-eddy simulation output, from which it is found that the cloud properties can be retrieved within 5% of the mean truth. The full cloud-drizzle retrieval method is then applied to a selected ACCEPT campaign that took place in the Fall of 2014 in Cabauw, the Netherlands. One-to-one comparisons with three independent cloud-only or drizzle-only retrieval methods from the literature show that the results of our method are generally consistent with what is derived using the three independent methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900047694&hterms=digital+microwave&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddigital%2Bmicrowave','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900047694&hterms=digital+microwave&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Ddigital%2Bmicrowave"><span>Precipitation observed over the South China Sea by the Nimbus-7 Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> during Winter Monex</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Petty, Grant W.; Katsaros, Kristina B.</p> <p>1990-01-01</p> <p>Mesoscale cloud clusters near the northwestern coast of Borneo were observed by the Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) on three occasions during the Winter Monsoon Experiment in December 1978. A nondimensional form of the SMMR 37 GHz polarization difference is introduced and used to identify regions of precipitation, and these are compared with visible and infrared imagery from the GMS-1 geostationary satellite. For two of the three cloud cluster cases, quantitative comparisons are made between nearly simultaneous SMMR observations and reflectivity observations made by the MIT WR-73 digital weather radar at Bintulu. Though limited in scope, these represent the first known direct comparisons between digital radar-derived rain parameters and satellite passive <span class="hlt">microwave</span> observations of near-equatorial precipitation. SMMR 37 GHz observations are found to be much better indicators of fractional coverage of each SMMR footprint by rain than of average rain rate within the footprint. Total area coverage by precipitation is estimated for all three clusters using this result.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040035540&hterms=sampling+design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsampling%2Bdesign','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040035540&hterms=sampling+design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsampling%2Bdesign"><span>Design of an L-band <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> with Active Mitigation of Interference</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ellingson, S. W.; Johnson, J. T.</p> <p>2003-01-01</p> <p>Radio frequency interference (RFI) impairs L-band radiometry outside the protected 20 MHz frequency band around 1413 MHz. However, bandwidths of 100 MHz or more are desired for certain remote sensing applications as well as certain astronomy applications. Because much of the RFI in this band is from radars with pulse lengths on the order of microseconds, traditional <span class="hlt">radiometers</span> (i.e., those which directly measure total power or power spectral density integrated over time scales of milliseconds or greater) are poorly-suited to this task. Simply reducing integration time and discarding contaminated outputs may not be a practical answer due to the wide variety of modulations and pulse lengths observed in L-band RFI signals, the dynamic and complex nature of the associated propagation channels, and the logistical effort associated with post-measurement data editing. This motivates the design and development of <span class="hlt">radiometers</span> capable of coherent sampling and adaptive, real-time mitigation of interference. Such a <span class="hlt">radiometer</span> will be described in this presentation. This design is capable of coherently-sampling up to 100 MHz bandwidth at L-band. RFI mitigation is implemented in FPGA components so that real-time suppression is achieved. The system currently uses a cascade of basic time- and frequency- domain detection and blanking techniques; more advanced algorithms are un- der consideration. The modular FPGA-based architecture provides other benefits, such as the ability to implement extremely stable digital filters and the ability to reconfigure the system "on the fly". An overview of the basic design along with on-the-air results from an initial implementation will be provided in the presentation. Related L-band RFI surveys will be described to illustrate the relevance of this approach in a variety of operating conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030020903&hterms=sampling+design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsampling%2Bdesign','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030020903&hterms=sampling+design&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsampling%2Bdesign"><span>Design of an L-band <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> with Active Mitigation of Interference</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hampson, G. A.; Ellingson, S. W.; Johnson, J. T.</p> <p>2003-01-01</p> <p>Radio frequency interference (RFI) impairs L-band radiometry outside the protected 20 MHz frequency band around 1413 MHz. However, bandwidths of 100 MHz or more are desired for certain remote sensing applications as well as certain astronomy applications. Because much of the RFI in this band is from radars with pulse lengths on the order of microseconds, traditional <span class="hlt">radiometers</span> (i.e., those which directly measure total power or power spectral density integrated over time scales of milliseconds or greater) are poorly-suited to this task. Simply reducing integration time and discarding contaminated outputs may not be a practical answer due to the wide variety of modulations and pulse lengths observed in L-band RFI signals, the dynamic and complex nature of the associated propagation channels, and the logistical effort associated with post-measurement data editing. This motivates the design and development of <span class="hlt">radiometers</span> capable of coherent sampling and adaptive, real-time mitigation of interference. Such a <span class="hlt">radiometer</span> will be described in this presentation. This design is capable of coherently-sampling up to 100 MHz bandwidth at L-band. RFI mitigation is implemented in FPGA components so that real-time suppression is achieved. The system currently uses a cascade of basic time- and frequency-domain detection and blanking techniques; more advanced algorithms are under consideration. The modular FPGA-based architecture provides other benefits, such as the ability to implement extremely stable digital filters and the ability to reconfigure the system "on the fly". An overview of the basic design along with on-the-air results from an initial implementation will be provided in the presentation. Related L-band RFI surveys will be described to illustrate the relevance of this approach in a variety of operating conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002cosp...34E1901V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002cosp...34E1901V"><span>Observations of frozen skin of southern ocean from multifrequency scanning <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (MSMR) onboard oceansat - 1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vyas, N.; Bhandari, S.; Dash, M.; Pandey, P.; Khare, N.</p> <p></p> <p>Encircling the Antarctic, Southern Ocean connects all the three oceans of the world with fastest current system found anywhere in the world. The region is thermally very stable and is covered with ice, which has a strong seasonal variability. The sea ice pulsates annually with seasonal migration varying from 4 million square kilometer to 20 million square kilometer during summer and winter respectively. This has strong influence on energy balance of the ocean-ice-atmosphere system, and hence on atmospheric general circulation affecting weather and climate. Sea ice also works as an insulator thus inhibiting the energy flux between ocean and atmosphere. It also influences the ecosystem of the southern ocean, which has rich fish resources with global economic values such as krill and tooth fish. During winter Krill survives on algae found at the under side of the sea ice. The southern ocean is known to have high nutrition but low concentration of chlorophyll-a, which is a proxy of the phytoplankton. It is now understood that iron is the limiting factor as has been shown by various iron fertilization experiments. Passive <span class="hlt">microwave</span> radiometry from space has been extensively used for the study of sea ice types and concentration in the Arctic and the Antarctic regions. Since late 1970s, data from SMMR and SSM/I have been used to study trends in sea ice extent and area. We have further extended the above studies by using data from OCEANSAT - 1 MSMR. The data, acquired at 18 GHz (H) with 50 kilometer resolution and having a swath of 1360 kilometer and a repeat cycle of 2 days, was processed to generate the brightness temperature maps over the Antarctica for a period of 2 years and the results were analyzed in conjunction with those obtained earlier (since 1978) through the study of SMMR and SSM/I data. Besides strong seasonal variability, our analysis shows an increasing trend in the sea ice extent during the recent years and the rate appears to be accelerating contrary to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016P%26SS..122..101W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016P%26SS..122..101W"><span>Thermal behavior of regolith at cold traps on the moon's south pole: Revealed by Chang'E-2 <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wei, Guangfei; Li, Xiongyao; Wang, Shijie</p> <p>2016-03-01</p> <p>The long-term stability of <span class="hlt">water</span> ice at cold traps depends on subsurface temperature and regolith thermophysical properties. Based on Chang'E-2 <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data, we have inverted attenuation coefficient, thermal gradient and instantaneous temperature profiles at permanently shaded craters (Cabeus, Haworth and Shoemaker) on the Moon's south pole. The nonuniformity of the inverted attenuation coefficient within the craters reflects the inhomogeneous thermophysical properties of regolith. In addition, thermal gradient decreased significantly from the crater walls to the bottoms, which may be caused by scattered sunlight, internal heat flux and earthshine effect. Considering continuous supplement of <span class="hlt">water</span> ice (with volumetric fraction 0-10%) at cold traps, it changes subsurface thermophysical properties but has little effect on thermal gradient. We also assumed that abundant ice (10%) mixed with regolith, the inversion results showed that the maximum difference of diurnal temperatures between "wet" and dry regolith were no more than 0.5 K. That is, the effect of <span class="hlt">water</span> ice on subsurface thermal behavior can be neglected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985SPIE..544..112G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985SPIE..544..112G"><span>An Upward Looking Airborne Millimeter Wave <span class="hlt">Radiometer</span> For Atmospheric <span class="hlt">Water</span> Vapor Sounding And Rain Detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gagliano, J. A.; Platt, R. H.</p> <p>1985-10-01</p> <p>A 90/180 GHz multichannel <span class="hlt">radiometer</span> is currently under development for NASA's 1985 Hurricane Mission onboard the Convair 990 research aircraft. The <span class="hlt">radiometer</span> will be a fixed beam instrument with dual corrugated horns and a common lens antenna designed to operate simultaneously at 90 and 180 GHz. The all solid state front-end will contain three double side band data channels at 90 ± 3 GHz, 180 + 3 GHz, and 180 ± 7 GHz. These frequencies are chosen to coincide with those proposed for the Advanced Moisture Sounding Unit (AMSU) <span class="hlt">radiometer</span> which is scheduled for future orbital deployment onboard a Tiros-N satellite. The airborne <span class="hlt">radiometer</span> will mount in a window port on the CV-990 and will maintain a fixed beam view approximately 14 degrees off zenith. Primary scientific interests for this instrument are the gathering of atmospheric humidity data near the <span class="hlt">water</span> vapor absorption line of 183.35 GHz and the collection of atmospheric precipitation signatures at 90 GHz. The <span class="hlt">radiometer</span> design is a Dicke chopper arrangement selected to achieve maximum absolute temperature accuracy and minimum brightness temperature sensitivity. In addition, the instrument will be self-calibrating with built-in temperature controlled calibration loads. Analog outputs of the three data channels will be calibrated DC voltages representing the observed radiometric brightness temperatures over the selected integration time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810058821&hterms=contamination+soils&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcontamination%2Bsoils','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810058821&hterms=contamination+soils&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcontamination%2Bsoils"><span>Requirements of space-borne <span class="hlt">microwave</span> <span class="hlt">radiometers</span> for detecting soil moisture contents</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burke, H.-H. K.; Burke, W. J.</p> <p>1981-01-01</p> <p>A multilayer radiative transfer model for predicting the relationship between soil moisture content and <span class="hlt">microwave</span> emission is summarized. Attention is also given to the performance of various <span class="hlt">microwave</span> sensors for soil moisture retrieval; here, the requirements of a satellite sensor system for monitoring large-scale soil moisture conditions are discussed. These requirements are presented in terms of (1) the wavelength, (2) atmospheric contamination, (3) polarization, (4) frequency of observation, and (5) spatial resolution. Each parameter is discussed in terms of <span class="hlt">microwave</span> response. Previous aircraft data with extensive ground truth information are used to support the theories proposed. Trade-offs between the parameters and an optimum sensor system for space monitoring soil moisture information are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760007471','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760007471"><span>Design Data Collection with Skylab <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span>-Scatterometer S-193, Volume 1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moore, R. K.; Ulaby, F. T. (Principal Investigator)</p> <p>1975-01-01</p> <p>The author has identified the following significant results. Observations with S-193 have provided radar design information for systems to be flown on spacecraft, but only at 13.9 GHz and for land areas over the United States and Brazil plus a few other areas of the world for which this kind of analysis was not made. Observations only extended out to about 50 deg angle of incidence. The value of a sensor with such a gross resolution for most overland resource and status monitoring systems seems marginal, with the possible exception of monitoring soil moisture and major vegetation variations. The complementary nature of the scatterometer and <span class="hlt">radiometer</span> systems was demonstrated by the correlation analysis. Although <span class="hlt">radiometers</span> must have spatial resolutions dictated by antenna size, radars can use synthetic aperture techniques to achieve much finer resolutions. Multiplicity of modes in the S-193 sensors complicated both the system development and its employment. An attempt was made in the design of the S-193 to arrange optimum integration times for each angle and type of measurement. This unnecessarily complicated the design of the instrument, since the gains in precision achieved in this way were marginal. Either a software-controllable integration time or a set of only two or three integration times would have been better.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/419613','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/419613"><span>Classification of Baltic Sea ice types by airborne multifrequency <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kurvonen, L.; Hallikainen, M.</p> <p>1996-11-01</p> <p>An airborne multifrequency <span class="hlt">radiometer</span> (24, 34, 48, and 94 GHz, vertical polarization) was used to investigate the behavior of the brightness temperature of different sea ice types in the Gulf of Bothnia (Baltic Sea). The measurements and the main results of the analysis are presented. The measurements were made in dry and wet conditions (air temperature above and below 0 C). The angle of incidence was 45{degree} in all measurements. The following topics are evaluated: (a) frequency dependency of the brightness temperature of different ice types, (b) the capability of the multifrequency <span class="hlt">radiometer</span> to classify ice types for winter navigation purposes, and (c) the optimum measurement frequencies for mapping sea ice. The weather conditions had a significant impact on the radiometric signatures of some ice types (snow-covered compact pack ice and frost-covered new ice); the impact was the highest at 94 GHz. In all cases the overall classification accuracy was around 90% (the kappa coefficient was from 0.86 to 0.96) when the optimum channel combination (24/34 GHz and 94 GHz) was used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950048007&hterms=bootstrap&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dbootstrap','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950048007&hterms=bootstrap&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dbootstrap"><span>Arctic sea ice concentrations from special sensor <span class="hlt">microwave</span> imager and advanced very high resolution <span class="hlt">radiometer</span> satellite data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Emery, W. J.; Fowler, C.; Maslanik, J.</p> <p>1994-01-01</p> <p>Nearly coincident data from the special sensor <span class="hlt">microwave</span> imager (SSM/I) and the advanced very high resolution <span class="hlt">radiometer</span> (AVHRR) are used to compute and compare Arctic sea ice concentrations for different regions and times of the year. To help determine overall accuracies and to highlight sources of differences between passive <span class="hlt">microwave</span>, optical wavelength, and thermal wavelength data, ice concentrations are estimated using two operational SSM/I ice concentration algorithms and with visible- and thermal-infrared wavelength AVHRR data. All algorithms capture the seasonal patterns of ice growth and melt. The ranges of differences fall within the general levels of uncertainty expected for each method and are similar to previous accuracy estimates. The estimated ice concentrations are all highly correlated, with uniform biases, although differences between individual pairs of observations can be large. On average, the NASA Team algorithm yielded 5% higher ice concentrations than the Bootstrap algorithm, while during nonmelt periods the two SSM/I algorithms agree to within 0.5%. These seasonal differences are consistent with the ways that the 19-GHz and 37-GHz <span class="hlt">microwave</span> channels are used in the algorithms. When compared to the AVHRR-derived ice concentrations, the Team-algorithm results are more similar on average in terms of correlation and mean differences. However, the Team algorithm underestimates concentrations relative to the AVHRR output by 6% during cold months and overestimates by 3% during summer. Little seasonal difference exists between the Bootstrap and AVHRR results, with a mean difference of about 5%. Although the mean differences are less between the SSM/I-derived concentrations and concentrations estimated using AVHRR channel 1, the correlations appear substantially better between the SSM/I data and concentrations derived from AVHRR channel 4, particularly for the Team algorithm output.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950048007&hterms=high+resolution+melt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhigh%2Bresolution%2Bmelt','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950048007&hterms=high+resolution+melt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhigh%2Bresolution%2Bmelt"><span>Arctic sea ice concentrations from special sensor <span class="hlt">microwave</span> imager and advanced very high resolution <span class="hlt">radiometer</span> satellite data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Emery, W. J.; Fowler, C.; Maslanik, J.</p> <p>1994-01-01</p> <p>Nearly coincident data from the special sensor <span class="hlt">microwave</span> imager (SSM/I) and the advanced very high resolution <span class="hlt">radiometer</span> (AVHRR) are used to compute and compare Arctic sea ice concentrations for different regions and times of the year. To help determine overall accuracies and to highlight sources of differences between passive <span class="hlt">microwave</span>, optical wavelength, and thermal wavelength data, ice concentrations are estimated using two operational SSM/I ice concentration algorithms and with visible- and thermal-infrared wavelength AVHRR data. All algorithms capture the seasonal patterns of ice growth and melt. The ranges of differences fall within the general levels of uncertainty expected for each method and are similar to previous accuracy estimates. The estimated ice concentrations are all highly correlated, with uniform biases, although differences between individual pairs of observations can be large. On average, the NASA Team algorithm yielded 5% higher ice concentrations than the Bootstrap algorithm, while during nonmelt periods the two SSM/I algorithms agree to within 0.5%. These seasonal differences are consistent with the ways that the 19-GHz and 37-GHz <span class="hlt">microwave</span> channels are used in the algorithms. When compared to the AVHRR-derived ice concentrations, the Team-algorithm results are more similar on average in terms of correlation and mean differences. However, the Team algorithm underestimates concentrations relative to the AVHRR output by 6% during cold months and overestimates by 3% during summer. Little seasonal difference exists between the Bootstrap and AVHRR results, with a mean difference of about 5%. Although the mean differences are less between the SSM/I-derived concentrations and concentrations estimated using AVHRR channel 1, the correlations appear substantially better between the SSM/I data and concentrations derived from AVHRR channel 4, particularly for the Team algorithm output.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011RaSc...46.0F08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011RaSc...46.0F08S"><span>Five-band <span class="hlt">microwave</span> <span class="hlt">radiometer</span> system for noninvasive brain temperature measurement in newborn babies: Phantom experiment and confidence interval</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sugiura, T.; Hirata, H.; Hand, J. W.; van Leeuwen, J. M. J.; Mizushina, S.</p> <p>2011-10-01</p> <p>Clinical trials of hypothermic brain treatment for newborn babies are currently hindered by the difficulty in measuring deep brain temperatures. As one of the possible methods for noninvasive and continuous temperature monitoring that is completely passive and inherently safe is passive <span class="hlt">microwave</span> radiometry (MWR). We have developed a five-band <span class="hlt">microwave</span> <span class="hlt">radiometer</span> system with a single dual-polarized, rectangular waveguide antenna operating within the 1-4 GHz range and a method for retrieving the temperature profile from five radiometric brightness temperatures. This paper addresses (1) the temperature calibration for five <span class="hlt">microwave</span> receivers, (2) the measurement experiment using a phantom model that mimics the temperature profile in a newborn baby, and (3) the feasibility for noninvasive monitoring of deep brain temperatures. Temperature resolutions were 0.103, 0.129, 0.138, 0.105 and 0.111 K for 1.2, 1.65, 2.3, 3.0 and 3.6 GHz receivers, respectively. The precision of temperature estimation (2σ confidence interval) was about 0.7°C at a 5-cm depth from the phantom surface. Accuracy, which is the difference between the estimated temperature using this system and the measured temperature by a thermocouple at a depth of 5 cm, was about 2°C. The current result is not satisfactory for clinical application because the clinical requirement for accuracy must be better than 1°C for both precision and accuracy at a depth of 5 cm. Since a couple of possible causes for this inaccuracy have been identified, we believe that the system can take a step closer to the clinical application of MWR for hypothermic rescue treatment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.H21C..07W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.H21C..07W"><span>Evaluation of Data from the Multi-frequency Scanning <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (MSMR) and Its Potential for Soil Moisture Retrieval</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wen, J.; Jackson, T. J.; Bindlish, R.; Su, Z. B.</p> <p>2003-12-01</p> <p>The Multi-frequency Scanning <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (MSMR) aboard the India Space Research Organization - Oceansat-1 (IRS-P4) platform measured land surface brightness temperature at low frequencies and provided an opportunity for exploring large-scale soil moisture retrieval during its two years period of observation. Several data issues had to be addressed before using the data. These included geolocation errors, data calibration and anthropogenic Radio-frequency Interference (RFI). Calibration was evaluated by comparisons to the Tropical Rainfall Measuring Mission/<span class="hlt">Microwave</span> Imager (TRMM/TMI) measured brightness temperatures. A negative bias of 3.4 and 3.6 K were observed for the 10.6 GHz horizontal and vertical polarization bands respectively, negative differences of 14.0 and 10.1 K were found between the MSMR 6.6 GHz and TMI 10.6 GHz horizontal and vertical polarizations over land surface. These results suggested that additional calibration of the MSMR data was required. Comparisons between the MSMR measured brightness temperature and ground measured volumetric soil moisture collected during two field campaigns indicated that the lower frequency and horizontal polarization had higher sensitivity to the ground soil moisture. Using a previously developed soil emission model, multi-temporal soil moisture was retrieved for the continental United States. Comparisons between the MSMR based soil moisture and ground measured volumetric soil moisture indicated an uncertain error of 3.8 percent in the estimated soil moisture. This data may provide a valuable extension to the SMMR and AMSR instruments since it covers a portion of the time between the two missions. Keywords: passive <span class="hlt">microwave</span>, brightness temperature, soil moisture, satellite remote sensing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H41L..06P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H41L..06P"><span>Using Passive <span class="hlt">Microwaves</span> for Open <span class="hlt">Water</span> Monitoring and Flood Forecasting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parinussa, R.; Johnson, F.; Sharma, A.; Lakshmi, V.</p> <p>2015-12-01</p> <p>One of the biggest and severest natural disasters that society faces is floods. An important component that can help in reducing the impact of floods is satellite remote sensing as it allows for consistent monitoring and obtaining catchment information in absence of physical contact. Nowadays, passive <span class="hlt">microwave</span> remote sensing observations are available in near real time (NRT) with a couple of hours delay from the actual sensing. The Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> 2 (AMSR2) is a multi-frequency passive <span class="hlt">microwave</span> sensor onboard the Global Change Observation Mission 1 - <span class="hlt">Water</span> that was launched in May 2012. Several of these frequencies have a high sensitivity to the land surface and they also have the capacity to penetrate clouds. These advantages come at the cost of the relatively coarse spatial resolution (footprints range from ~5 to ~50 km) which in turn allows for global monitoring. A relatively simple methodology to monitor the fraction of open <span class="hlt">water</span> from AMSR2 observations is presented here. Low frequency passive <span class="hlt">microwave</span> observations have sensitivity to the land surface but are modulated by overlying signals from physical temperature and vegetation cover. We developed a completely <span class="hlt">microwave</span> based artificial neural network supported by physically based components to monitor the fraction of open <span class="hlt">water</span>. Three different areas, located in China, Southeast Asia and Australia, were selected for testing purposes and several different characteristics were examined. First, the overall performance of the methodology was evaluated against the NASA NRT Global Flood Mapping system. Second, the skills of the various different AMSR2 frequencies were tested and revealed that artificial contamination is a factor to consider. The different skills of the tested frequencies are of interest to apply the methodology to alternative passive <span class="hlt">microwave</span> sensors. This will be of benefit in using the numerous multi-frequency passive <span class="hlt">microwaves</span> sensors currently observing our Earth</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=308109','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=308109"><span>Amplitude of the diurnal temperature cycle as observed by thermal infrared and <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Land surface temperature (LST) is a key input to physically-based retrieval algorithms of hydrological states and fluxes, and global measurements of LST are provided by many satellite platforms. Passive <span class="hlt">microwave</span> (MW) observations offer an alternative to conventional thermal infrared (TIR) LST retri...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27411122','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27411122"><span>Stray light effects in above-<span class="hlt">water</span> remote-sensing reflectance from hyperspectral <span class="hlt">radiometers</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Talone, Marco; Zibordi, Giuseppe; Ansko, Ilmar; Banks, Andrew Clive; Kuusk, Joel</p> <p>2016-05-20</p> <p>Stray light perturbations are unwanted distortions of the measured spectrum due to the nonideal performance of optical <span class="hlt">radiometers</span>. Because of this, stray light characterization and correction is essential when accurate radiometric measurements are a necessity. In agreement with such a need, this study focused on stray light correction of hyperspectral <span class="hlt">radiometers</span> widely applied for above-<span class="hlt">water</span> measurements to determine the remote-sensing reflectance (R<sub>RS</sub>). Stray light of sample <span class="hlt">radiometers</span> was experimentally characterized and a correction algorithm was developed and applied to field measurements performed in the Mediterranean Sea. Results indicate that mean stray light corrections are appreciable, with values generally varying from -1% to +1% in the 400-700 nm spectral region for downward irradiance and sky radiance, and from -1% to +4% for total radiance from the sea. Mean corrections for data products such as R<sub>RS</sub> exhibit values that depend on <span class="hlt">water</span> type varying between -0.5% and +1% in the blue-green spectral region, with peaks up to 9% in the red in eutrophic <span class="hlt">waters</span>. The possibility of using one common stray light correction matrix for the analyzed class of <span class="hlt">radiometers</span> was also investigated. Results centered on R<sub>RS</sub> support such a feasibility at the expense of an increment of the uncertainty typically well below 0.5% in the blue-green and up to 1% in the red, assuming sensors are based on spectrographs from the same production batch.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930004274','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930004274"><span>Phased array feed design technology for Large Aperture <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (LAMR) Earth observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schuman, H. K.</p> <p>1992-01-01</p> <p>An assessment of the potential and limitations of phased array antennas in space-based geophysical precision radiometry is described. Mathematical models exhibiting the dependence of system and scene temperatures and system sensitivity on phased array antenna parameters and components such as phase shifters and low noise amplifiers (LNA) are developed. Emphasis is given to minimum noise temperature designs wherein the LNA's are located at the array level, one per element or subarray. Two types of combiners are considered: array lenses (space feeds) and corporate networks. The result of a survey of suitable components and devices is described. The data obtained from that survey are used in conjunction with the mathematical models to yield an assessment of effective array antenna noise temperature for representative geostationary and low Earth orbit systems. Practical methods of calibrating a space-based, phased array <span class="hlt">radiometer</span> are briefly addressed as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800009067','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800009067"><span>Alternative Beam Efficiency Calculations for a Large-aperture Multiple-frequency <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (LAMMR)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmidt, R. F.</p> <p>1979-01-01</p> <p>The fundamental definition of beam efficiency, given in terms of a far field radiation pattern, was used to develop alternative definitions which improve accuracy, reduce the amount of calculation required, and isolate the separate factors composing beam efficiency. Well-known definitions of aperture efficiency were introduced successively to simplify the denominator of the fundamental definition. The superposition of complex vector spillover and backscattered fields was examined, and beam efficiency analysis in terms of power patterns was carried out. An extension from single to dual reflector geometries was included. It is noted that the alternative definitions are advantageous in the mathematical simulation of a <span class="hlt">radiometer</span> system, and are not intended for the measurements discipline where fields have merged and therefore lost their identity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AMTD....5.5107R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AMTD....5.5107R"><span>First middle-atmospheric zonal wind profile measurements with a new ground-based <span class="hlt">microwave</span> Doppler-spectro-<span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rüfenacht, R.; Kämpfer, N.; Murk, A.</p> <p>2012-07-01</p> <p>We report on the wind <span class="hlt">radiometer</span> WIRA, a new ground-based <span class="hlt">microwave</span> Doppler-spectro-<span class="hlt">radiometer</span> specifically designed for the measurement of middle-atmospheric horizontal wind by observing ozone emission spectra at 142.17504 GHz. Currently, wind speeds in five levels between 30 and 79 km can be retrieved what makes WIRA the first instrument able to continuously measure horizontal wind in this altitude range. For an integration time of one day the measurement error on each level lies at around 25 m s-1. With a planned upgrade this value is expected to be reduced by a factor of 2 in the near future. On the altitude levels where our measurement can be compared to wind data from the European Centre for Medium-Range Weather Forecasts (ECMWF) very good agreement in the long-term statistics as well as in short time structures with a duration of a few days has been found. WIRA uses a passive double sideband heterodyne receiver together with a digital Fourier transform spectrometer for the data acquisition. A big advantage of the radiometric approach is that such instruments can also operate under adverse weather conditions and thus provide a continuous time series for the given location. The optics enables the instrument to scan a wide range of azimuth angles including the directions east, west, north, and south for zonal and meridional wind measurements. The design of the <span class="hlt">radiometer</span> is fairly compact and its calibration does not rely on liquid nitrogen what makes it transportable and suitable for campaign use. WIRA is conceived in a way that it can be operated remotely and does hardly require any maintenance. In the present paper, a description of the instrument is given, and the used techniques for the wind retrieval based on the determination of the Doppler shift of the measured atmospheric ozone emission spectra are outlined. Their reliability was tested using MonteCarlo simulations. Finally, a first time series of 11 months of zonal wind measurements over Bern (46°57</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140017808','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140017808"><span>In-situ <span class="hlt">Microwave</span> Brightness Temperature Variability from Ground-based <span class="hlt">Radiometer</span> Measurements at Dome C in Antarctica Induced by Wind-formed Features</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Royer, A.; Picard, G.; Arnaud, L.; Brucker, L.; Fily, M..</p> <p>2014-01-01</p> <p>Space-borne <span class="hlt">microwave</span> <span class="hlt">radiometers</span> are among the most useful tools to study snow and to collect information on the Antarctic climate. They have several advantages over other remote sensing techniques: high sensitivity to snow properties of interest (temperature, grain size, density), subdaily coverage in the polar regions, and their observations are independent of cloud conditions and solar illumination. Thus, <span class="hlt">microwave</span> <span class="hlt">radiometers</span> are widely used to retrieve information over snow-covered regions. For the Antarctic Plateau, many studies presenting retrieval algorithms or numerical simulations have assumed, explicitly or not, that the subpixel-scale heterogeneity is negligible and that the retrieved properties were representative of whole pixels. In this presentation, we investigate the spatial variations of brightness temperature over arange of a few kilometers in the Dome C area (Antarctic Plateau).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1015232','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1015232"><span><span class="hlt">Microwave</span> and Millimeter-Wave Radiometric Studies of Temperature, <span class="hlt">Water</span> Vapor and Clouds</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Westwater, Edgeworth</p> <p>2011-05-06</p> <p>The importance of accurate measurements of column amounts of <span class="hlt">water</span> vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both <span class="hlt">microwave</span> <span class="hlt">radiometers</span> (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable <span class="hlt">Water</span> Vapor (PWV) and Liquid <span class="hlt">Water</span> Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of <span class="hlt">water</span> vapor, this is especially important during the Arctic winter, when PWV is frequently less than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - <span class="hlt">Water</span> Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the <span class="hlt">radiometer</span> group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning <span class="hlt">Radiometer</span> (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved <span class="hlt">water</span> vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of <span class="hlt">radiometers</span> to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of <span class="hlt">microwave</span> and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third year of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860011207','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860011207"><span>Development of UHF <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kendall, B. M.; Blume, H. J. C.; Cross, A. E.</p> <p>1985-01-01</p> <p>A wideband multifrequency UHF <span class="hlt">radiometer</span> was initially developed to operate in the 500 to 710 MHz frequency range for the remote measurement of ocean <span class="hlt">water</span> salinity. However, radio-frequency interference required a reconfiguration to operate in the single-frequency radio astronomy band of 608 to 614 MHz. Details of the <span class="hlt">radiometer</span> development and testing are described. Flight testing over variable terrain provided a performance comparison of the UHF <span class="hlt">radiometer</span> with an L-band <span class="hlt">radiometer</span> for remote sensing of geophysical parameters. Although theoretically more sensitive, the UHF <span class="hlt">radiometer</span> was found to be less desirable in practice than the L-band <span class="hlt">radiometer</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A53A0369R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A53A0369R"><span>Development of the Tropospheric <span class="hlt">Water</span> Vapor and Cloud ICE (TWICE) Millimeter- and Sub-millimeter Wave <span class="hlt">Radiometer</span> Instrument for 6U-Class Nanosatellites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reising, S. C.; Kangaslahti, P.; Schlecht, E.; Bosch-Lluis, X.; Ogut, M.; Padmanabhan, S.; Cofield, R.; Chahat, N.; Brown, S. T.; Jiang, J. H.; Deal, W.; Zamora, A.; Leong, K.; Shih, S.; Mei, G.</p> <p>2015-12-01</p> <p>Measurements of upper-tropospheric <span class="hlt">water</span> vapor and cloud ice at a variety of local times are critically needed to provide information not currently available from <span class="hlt">microwave</span> sensors in sun-synchronous orbits. Such global measurements would enable increasingly accurate cloud and moisture simulations in global circulation models, improving both climate predictions and knowledge of their uncertainty. In addition, this capability would address the need for measurements of cloud ice particle size distribution and <span class="hlt">water</span> content in both clean and polluted environments. Complementary measurements of aerosol pollution would allow investigation of its effects on cloud properties and climate. This is particularly important since the uncertainty in the aerosol effect on climate is at least four times as great as the uncertainty in greenhouse gas effects. To address this unmet need, a collaborative team among Colorado State University, Caltech Jet Propulsion Laboratory and Northrop Grumman Corporation is developing and fabricating the Tropospheric <span class="hlt">Water</span> and Cloud ICE (TWICE) <span class="hlt">radiometer</span> instrument. TWICE is designed with size, mass, power consumption and downlink data rate compatible with deployment aboard a 6U-Class nanosatellite. TWICE is advancing the state of the art of spaceborne millimeter- and submillimeter-wave <span class="hlt">radiometers</span> by transitioning from Schottky mixer-based front ends to InP HEMT MMIC low-noise amplifier front ends, substantially reducing the <span class="hlt">radiometer</span>'s mass, volume and power consumption. New low-noise amplifiers and related front-end components are being designed and fabricated by JPL and Northrop Grumman based on InP HEMT MMIC technology up to 670 GHz. The TWICE instrument will provide 16 <span class="hlt">radiometer</span> channels, including window frequencies near 240, 310 and 670 GHz to perform ice particle sizing and determine total ice <span class="hlt">water</span> content, as well as four sounding channels each near 118 GHz for temperature sounding and near 183 GHz and 380 GHz for <span class="hlt">water</span> vapor sounding</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.4275P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.4275P"><span>LIRAS mission for lunar exploration by <span class="hlt">microwave</span> interferometric <span class="hlt">radiometer</span>: Moon's subsurface characterization, emission model and numerical simulator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pompili, Sara; Silvio Marzano, Frank; Di Carlofelice, Alessandro; Montopoli, Mario; Talone, Marco; Crapolicchio, Raffaele; L'Abbate, Michelangelo; Varchetta, Silvio; Tognolatti, Piero</p> <p>2013-04-01</p> <p>The "Lunar Interferometric <span class="hlt">Radiometer</span> by Aperture Synthesis" (LIRAS) mission is promoted by the Italian Space Agency and is currently in feasibility phase. LIRAS' satellite will orbit around the Moon at a height of 100 km, with a revisiting time period lower than 1 lunar month and will be equipped with: a synthetic aperture <span class="hlt">radiometer</span> for subsurface sounding purposes, working at 1 and 3 GHz, and a real aperture <span class="hlt">radiometer</span> for near-surface probing, working at 12 and 24 GHz. The L-band payload, representing a novel concept for lunar exploration, is designed as a Y-shaped thinned array with three arms less than 2.5 m long. The main LIRAS objectives are high-resolution mapping and vertical sounding of the Moon subsurface by applying the advantages of the antenna aperture synthesis technique to a multi-frequency <span class="hlt">microwave</span> passive payload. The mission is specifically designed to achieve spatial resolutions less than 10 km at surface and to retrieve thermo-morphological properties of the Moon subsurface within 5 m of depth. Among LIRAS products are: lunar near-surface brightness temperature, subsurface brightness temperature gross profile, subsurface regolith thickness, density and average thermal conductivity, detection index of possible subsurface discontinuities (e.g. ice presence). The following study involves the preliminary design of the LIRAS payload and the electromagnetic and thermal characterization of the lunar subsoil through the implementation of a simulator for reproducing the LIRAS measurements in response to observations of the Moon surface and subsurface layers. Lunar physical data, collected after the Apollo missions, and LIRAS instrument parameters are taken as input for the abovementioned simulator, called "LIRAS End-to-end Performance Simulator" (LEPS) and obtained by adapting the SMOS End-to-end Performance Simulator to the different instrumental, orbital, and geophysical LIRAS characteristics. LEPS completely simulates the behavior of the satellite</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900039519&hterms=Nimbus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DNimbus','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900039519&hterms=Nimbus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DNimbus"><span>The beam filling error in the Nimbus 5 electronically scanning <span class="hlt">microwave</span> <span class="hlt">radiometer</span> observations of Global Atlantic Tropical Experiment rainfall</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Short, David A.; North, Gerald R.</p> <p>1990-01-01</p> <p>A comparison of rain rates retrieved from the Nimbus 5 electronically scanning <span class="hlt">microwave</span> <span class="hlt">radiometer</span> brightness temperatures and observed from shipboard radars during the Global Atlantic Tropical Experiment (GATE) phase I shows that the beam filling error is the major source of discrepancy between the two. When averaged over a large scene (the GATE radar array, 400 km in diameter), the beam filling error is quite stable, being 50 percent of the observed rain rate. This suggests the simple procedure of multiplying retrieved rain rates by 2 (correction factor). A statistical model of the beam filling error is developed by envisioning an idealized instrument field-of-view that encompasses an entire gamma distribution of rain rates. A modeled correction factor near 2 is found for rain rate and temperature characteristics consistent with GATE conditions. The statistical model also suggests that the correction factor varies from 1.5 to 2.5 for suppressed to enhanced tropical convective regimes, and decreases to 1.5 as the freezing level and average depth of the rain column decreases to 2.5 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002PCE....27..309P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002PCE....27..309P"><span>Comparison of atmospheric parameters derived from GPS, VLBI and a ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> in Italy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pacione, R.; Fionda, E.; Ferrara, R.; Lanotte, R.; Sciarretta, C.; Vespe, F.</p> <p></p> <p>Integrated Precipitable <span class="hlt">Water</span> Vapor (IPWV) derived from GPS, <span class="hlt">water</span> vapor <span class="hlt">radiometer</span> WVR-1100 and RAdiosonde OBservation (RAOB) have been compared for the Cagliari site (Italy) on a seasonal and annual bases. The comparison analysis on estimating IPWV among the three independent techniques (GPS, WVR-110 and RAOB) has shown high accuracy equal to 0.136 cm with a bias of -0.049 cm throughout 1999. Furthermore, a comparison has been made between the estimated atmospheric parameters, equivalent zenith tropospheric delay (ZTD) and horizontal gradient, as resulting from independent analyses of GPS and VLBI data for the three Italian collocated stations: Matera, Medicina and Noto. We have realized that VLBI ZTD estimates are lower than that obtained by GPS of about 1.0-1.5 cm, while the standard deviations range from 0.5 to 2.0 cm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090009345','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090009345"><span>Combining Satellite <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> and Radar Observations to Estimate Atmospheric Latent Heating Profiles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grecu, Mircea; Olson, William S.; Shie, Chung-Lin; L'Ecuyer, Tristan S.; Tao, Wei-Kuo</p> <p>2009-01-01</p> <p>In this study, satellite passive <span class="hlt">microwave</span> sensor observations from the TRMM <span class="hlt">Microwave</span> Imager (TMI) are utilized to make estimates of latent + eddy sensible heating rates (Q1-QR) in regions of precipitation. The TMI heating algorithm (TRAIN) is calibrated, or "trained" using relatively accurate estimates of heating based upon spaceborne Precipitation Radar (PR) observations collocated with the TMI observations over a one-month period. The heating estimation technique is based upon a previously described Bayesian methodology, but with improvements in supporting cloud-resolving model simulations, an adjustment of precipitation echo tops to compensate for model biases, and a separate scaling of convective and stratiform heating components that leads to an approximate balance between estimated vertically-integrated condensation and surface precipitation. Estimates of Q1-QR from TMI compare favorably with the PR training estimates and show only modest sensitivity to the cloud-resolving model simulations of heating used to construct the training data. Moreover, the net condensation in the corresponding annual mean satellite latent heating profile is within a few percent of the annual mean surface precipitation rate over the tropical and subtropical oceans where the algorithm is applied. Comparisons of Q1 produced by combining TMI Q1-QR with independently derived estimates of QR show reasonable agreement with rawinsonde-based analyses of Q1 from two field campaigns, although the satellite estimates exhibit heating profile structure with sharper and more intense heating peaks than the rawinsonde estimates. 2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790011020','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790011020"><span>Feasibility Study of Graphite Epoxy Antenna for a <span class="hlt">Microwave</span> Limb Sounder <span class="hlt">Radiometer</span> (MLSR)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1979-01-01</p> <p>Results are presented of a feasibility study to design graphite epoxy antenna reflectors for a jet propulsion laboratory <span class="hlt">microwave</span> limb sounder instrument (MLSR). Two general configurations of the offset elliptic parabolic reflectors are presented that will meet the requirements on geometry and reflector accuracy. The designs consist of sandwich construction for the primary reflectors, secondary reflector support structure and cross-tie members between reflector pairs. Graphite epoxy materials of 3 and 6 plies are used in the facesheets of the sandwich. An aluminum honeycomb is used for the core. A built-in adjustment system is proposed to reduce surface distortions during assembly. The manufacturing and environmental effects are expected to result in surface distortions less than .0015 inch and pointing errors less than .002 degree.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950048946&hterms=interest+rate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dinterest%2Brate','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950048946&hterms=interest+rate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dinterest%2Brate"><span>Model studies of the beam-filling error for rain-rate retrieval with <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ha, Eunho; North, Gerald R.</p> <p>1995-01-01</p> <p>Low-frequency (less than 20 GHz) single-channel <span class="hlt">microwave</span> retrievals of rain rate encounter the problem of beam-filling error. This error stems from the fact that the relationship between <span class="hlt">microwave</span> brightness temperature and rain rate is nonlinear, coupled with the fact that the field of view is large or comparable to important scales of variability of the rain field. This means that one may not simply insert the area average of the brightness temperature into the formula for rain rate without incurring both bias and random error. The statistical heterogeneity of the rain-rate field in the footprint of the instrument is key to determining the nature of these errors. This paper makes use of a series of random rain-rate fields to study the size of the bias and random error associated with beam filling. A number of examples are analyzed in detail: the binomially distributed field, the gamma, the Gaussian, the mixed gamma, the lognormal, and the mixed lognormal ('mixed' here means there is a finite probability of no rain rate at a point of space-time). Of particular interest are the applicability of a simple error formula due to Chiu and collaborators and a formula that might hold in the large field of view limit. It is found that the simple formula holds for Gaussian rain-rate fields but begins to fail for highly skewed fields such as the mixed lognormal. While not conclusively demonstrated here, it is suggested that the notionof climatologically adjusting the retrievals to remove the beam-filling bias is a reasonable proposition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750021530','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750021530"><span>A feasibility study of a <span class="hlt">microwave</span> <span class="hlt">water</span> vapor measurement from a space probe along an occultation path</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Longbothum, R. L.</p> <p>1975-01-01</p> <p>Stratospheric and mesospheric <span class="hlt">water</span> vapor measurements were taken using the <span class="hlt">microwave</span> lines at 22 GHz (22.235 GHz) and 183 GHz (183.31 GHz). The resonant cross sections for both the 22 GHz and the 183 GHz lines were used to model the optical depth of atmospheric <span class="hlt">water</span> vapor. The range of optical depths seen by a <span class="hlt">microwave</span> <span class="hlt">radiometer</span> through the earth's limb was determined from radiative transfer theory. <span class="hlt">Radiometer</span> sensitivity, derived from signal theory, was compared with calculated optical depths to determine the maximum height to which <span class="hlt">water</span> vapor can be measured using the following methods: passive emission, passive absorption, and active absorption. It was concluded that measurements using the 22 GHz line are limited to about 50 km whereas the 183 GHz line enables measurements up to and above 100 km for <span class="hlt">water</span> vapor mixing ratios as low as 0.1 ppm under optimum conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1392927','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1392927"><span>An Improved Liquid <span class="hlt">Water</span> Absorption Model at <span class="hlt">Microwave</span> Frequencies for Supercooled Liquid <span class="hlt">Water</span> Clouds</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Turner, D. D.; Kneifel, Stefan; Cadeddu, M. P.</p> <p>2016-01-01</p> <p>An improved liquid <span class="hlt">water</span> absorption model is developed for frequencies between 0.5 and 500 GHz. The empirical coefficients for this model were retrieved from a dataset that consists of both laboratory observations of the permittivity of liquid <span class="hlt">water</span> (primarily at temperatures above 0 degrees C) and field observations collected by <span class="hlt">microwave</span> <span class="hlt">radiometers</span> in three separate locations with observations at temperatures as low as -32 degrees C. An optimal estimation framework is used to retrieve the model's coefficients. This framework shows that there is high information content in the observations for seven of the nine model coefficients, but that the uncertainties in all of the coefficients result in less than 15% uncertainty in the liquid <span class="hlt">water</span> absorption coefficient for all temperatures between -32 degrees and 0 degrees C and frequencies between 23 and 225 GHz. Furthermore, this model is more consistent with both the laboratory and field observations over all frequencies and temperatures than other popular absorption models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6442012','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6442012"><span>Interaction of oil with sea ice. Appendix 4. The Bering Sea ice cover during March 1979: comparison of surface and satellite data with the Nimbus-7 smmr (scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span>)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Martin, S.; McNutt, S.L.; Cavalieri, D.J.; Gloersen, P.</p> <p>1982-01-01</p> <p>During March 1979, field operations were carried out in the Marginal Ice Zone (MIZ) of the Bering Sea. This report presents the results of a comparison between surface and aircraft observations, and images from the Tiros-N satellite, with ice concentrations derived from the <span class="hlt">microwave</span> radiances of the Nimbus-7 Scanning Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996ApJ...460....1K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996ApJ...460....1K"><span>High-Latitude Galactic Emission in the COBE Differential <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> 2 Year Sky Maps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kogut, A.; Banday, A. J.; Bennett, C. L.; Gorski, K. M.; Hinshaw, G.; Reach, W. T.</p> <p>1996-03-01</p> <p>We cross-correlate the COBE6 DMR 2 year sky maps with spatial templates from long-wavelength radio surveys and the far-infrared COBE DIRBE maps. We place an upper limit on the spectral index of synchrotron radiation βsynch < -2.9 between 408 MHz and 31.5 GHz. We obtain a statistically significant cross-correlation with the DIRBE maps, whose dependence on the DMR frequencies indicates a superposition of dust and free-free emission. The high-latitude dust emission (|b| > 30°) is well fitted by a single dust component with temperature T = 18+3-7 K and emissivity ν ∝ (υ/ν0)β with β = 1.9+3.0-0.5. The free-free emission is spatially correlated with the dust on angular scales larger than the 70 DMR beam, with rms variations 5.3±1.8 μK at 53 GHz and angular power spectrum p ∝ l-3. If this correlation persists to smaller angular scales, free-free emission should not be a significant contaminant to measurements of the cosmic <span class="hlt">microwave</span> anisotropy at degree angular scales for frequencies above 20 GHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..217a2035Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..217a2035Y"><span>Modelling batch <span class="hlt">microwave</span> heating of <span class="hlt">water</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yeong, S. P.; Law, M. C.; Lee, C. C. Vincent; Chan, Y. S.</p> <p>2017-07-01</p> <p>A numerical model of the <span class="hlt">microwave</span> heating of distilled <span class="hlt">water</span> is developed using COMSOL Multiphysics software to investigate the <span class="hlt">microwave</span> effects on the heating rate. Three frequencies (0.915GHz, 2GHz and 2.45 GHz) have been applied in the model in order to study their influences on the <span class="hlt">water</span> temperature. It is found that the <span class="hlt">water</span> heats up at 2GHz and 2.45GHz, however, there is no sign of heating at 915MHz. This is supported with the figures of the electric field distribution in the <span class="hlt">microwave</span> cavity. The results shown in the developed model is validated with the experimental results obtained at 2.45 GHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E2074M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E2074M"><span>Influence of (FeO + TiO2) abundance on the thermal emission from the lunar regolith using Chang'E-2 <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meng, Zhiguo; Ping, Jinsong; Xu, Yi; Cai, Zhanchuan; Zheng, Yongchun</p> <p></p> <p>Abstract:The <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data obtained from Chang’E-2 mission (CELMS data) has provided new opportunity to study the influence of the (FeO+TiO2) abundance on the <span class="hlt">microwave</span> thermal emission of the lunar regolith. In this paper, the radiative transfer simulation is employed to study the change of the brightness temperature with (FeO+TiO2) abundance at different frequencies and surface temperature. The (FeO+TiO2) abundance are derived from Clementine UV-VIS data and the samples from Apollo, Luna and Surveyor projects. The simulation results along the Equator indicate that the (FeO+TiO2) abundance has strong impact on the <span class="hlt">microwave</span> thermal emission of the lunar regolith. However, the data along the Longitude 0° shows that the (FeO+TiO2) abundance is not the dominant influential factor of the <span class="hlt">microwave</span> thermal emission of the lunar regolith. Specifically, the abnormal brightness temperature at 160°W (Unnamed crater), 138°W (Crater Vavilov), 125°W (Crater Hertzsprung), 116°E (Crater Abul Wáfa), 119°E (Crater Heron), 130°E (Crater Catena Gregory) and 140°E (Crater Catena Mendeleev) shows that the (FeO+TiO2) abundance is not the only influential factor for the observed brightness temperature. In addition, the correlations between the four-channel brightness temperature and the (FeO+TiO2) abundance in Apollo landing site and along the Equator both indicate that the (FeO+TiO2) abundance is slightly decreasing with depth. The research is essential for the inversion of the lunar regolith parameters with the <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data from Chang’E satellites. Keywords: lunar regolith, <span class="hlt">microwave</span> thermal emission, CELMS data, (FeO+TiO2) abundance</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AMT.....5.1359N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AMT.....5.1359N"><span>PHOCUS <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nyström, O.; Murtagh, D.; Belitsky, V.</p> <p>2012-06-01</p> <p>PHOCUS - Particles, Hydrogen and Oxygen Chemistry in the Upper Summer Mesosphere is a Swedish sounding rocket experiment, launched in July 2011, with the main goal of investigating the upper atmosphere in the altitude range 50-110 km. This paper describes the SondRad instrument in the PHOCUS payload, a <span class="hlt">radiometer</span> comprising two frequency channels (183 GHz and 557 GHz) aimed at exploring the <span class="hlt">water</span> vapour concentration distribution in connection with the appearance of noctilucent (night shining) clouds. The design of the <span class="hlt">radiometer</span> system has been done in a collaboration between Omnisys Instruments AB and the Group for Advanced Receiver Development (GARD) at Chalmers University of Technology where Omnisys was responsible for the overall design, implementation, and verification of the <span class="hlt">radiometers</span> and backend, whereas GARD was responsible for the <span class="hlt">radiometer</span> optics and calibration systems. The SondRad instrument covers the <span class="hlt">water</span> absorption lines at 183 GHz and 557 GHz. The 183 GHz channel is a side-looking <span class="hlt">radiometer</span>, while the 557 GHz <span class="hlt">radiometer</span> is placed along the rocket axis looking in the forward direction. Both channels employ sub-harmonically pumped Schottky mixers and Fast Fourier Transform Spectrometers (FFTS) backends with 67 kHz resolution. The <span class="hlt">radiometers</span> include novel calibration systems specifically adjusted for use with each frequency channel. The 183 GHz channel employs a continuous wave CW pilot signal calibrating the entire receiving chain, while the intermediate frequency chain (the IF-chain) of the 557 GHz channel is calibrated by injecting a signal from a reference noise source through a directional coupler. The instrument collected complete spectra for both the 183 GHz and the 557 GHz with 300 Hz data rate for the 183 GHz channel and 10 Hz data rate for the 557 GHz channel for about 60 s reaching the apogee of the flight trajectory and 100 s after that. With lossless data compression using variable resolution over the spectrum, the data set was</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AMTD....5..271N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AMTD....5..271N"><span>PHOCUS <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nyström, O.; Murtagh, D.; Belitsky, V.</p> <p>2012-01-01</p> <p>PHOCUS - Particles, Hydrogen and Oxygen Chemistry in the Upper Summer Mesosphere is a Swedish sounding rocket experiment, launched in July 2011, with the main goal of investigating the upper atmosphere in the altitude range 50-110 km. This paper describes the SondRad instrument in the PHOCUS payload, the <span class="hlt">radiometer</span> comprising two frequency channels, 183 GHz and 557 GHz, aimed at exploring the <span class="hlt">water</span> vapour concentration distribution in connection with the appearance of noctilucent (night shining) clouds. The design of the <span class="hlt">radiometer</span> system has been done in a collaboration between Omnisys Instruments AB and the Group for Advanced Receiver Development (GARD) at Chalmers University of Technology where Omnisys was responsible for the overall design, implementation, and verification of the <span class="hlt">radiometers</span> and backend whereas GARD was responsible for the <span class="hlt">radiometer</span> optics and calibration systems. The SondRad instrument covers the <span class="hlt">water</span> absorption lines at 183 GHz and 557 GHz. The 183 GHz channel is a side-looking <span class="hlt">radiometer</span> while the 557 GHz <span class="hlt">radiometer</span> is placed along the rocket axis looking in the forward direction. Both channels employ sub-harmonically pumped Schottky mixers and FFT spectrometer backends with 67 kHz resolution. The <span class="hlt">radiometers</span> include novel calibration systems specifically adjusted for use with each frequency channel. The 183 GHz channel employs a CW-pilot signal calibrating the entire receiving chain while the IF-chain of the 557 GHz channel is calibrated by injecting a signal from a reference noise source through a directional coupler. The instrument collected complete spectra for both the 183 GHz and the 557 GHz with 300 Hz data rate for the 183 GHz channel and 10 Hz data rate for the 557 GHz channel for about 60 s reaching the apogee of the flight trajectory and 100 s after that. With lossless data compression using variable resolution over the spectrum, the data set was reduced to 2 × 12 MByte. The first results indicate that the instrument has</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900009944','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900009944"><span>Millimeter <span class="hlt">radiometer</span> system technology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, W. J.; Swanson, P. N.</p> <p>1989-01-01</p> <p>JPL has had a large amount of experience with spaceborne <span class="hlt">microwave</span>/millimeter wave <span class="hlt">radiometers</span> for remote sensing. All of the instruments use filled aperture antenna systems from 5 cm diameter for the <span class="hlt">microwave</span> Sounder Units (MSU), 16 m for the <span class="hlt">microwave</span> limb sounder (MLS) to 20 m for the large deployable reflector (LDR). The advantages of filled aperture antenna systems are presented. The requirements of the 10 m Geoplat antenna system, 10 m multified antenna, and the MLS are briefly discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AMT....10..155Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AMT....10..155Z"><span>Uncertainties of ground-based <span class="hlt">microwave</span> <span class="hlt">radiometer</span> retrievals in zenith and off-zenith observations under snow conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Wengang; Xu, Guirong; Liu, Yuanyuan; Yan, Guopao; Li, Dejun; Wang, Shengbo</p> <p>2017-01-01</p> <p>This paper is to investigate the uncertainties of <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (MWR) retrievals in snow conditions and also explore the discrepancies of MWR retrievals in zenith and off-zenith observations. The MWR retrievals were averaged in a ±15 min period centered at sounding times of 00:00 and 12:00 UTC and compared with radiosonde observations (RAOBs). In general, the MWR retrievals have a better correlation with RAOB profiles in off-zenith observations than in zenith observations, and the biases (MWR observations minus RAOBs) and root mean square errors (RMSEs) between MWR and RAOB are also clearly reduced in off-zenith observations. The biases of temperature, relative humidity, and vapor density decrease from 4.6 K, 9 %, and 1.43 g m-3 in zenith observations to -0.6 K, -2 %, and 0.10 g m-3 in off-zenith observations, respectively. The discrepancies between MWR retrievals and RAOB profiles by altitude present the same situation. Cases studies show that the impact of snow on accuracies of MWR retrievals is more serious in heavy snowfall than in light snowfall, but off-zenith observation can mitigate the impact of snowfall. The MWR measurements become less accurate in snowfall mainly due to the retrieval algorithm, which does not consider the effect of snow, and the accumulated snow on the top of the radome increases the signal noise of MWR measurements. As the snowfall drops away by gravity on the sides of the radome, the off-zenith observations are more representative of the atmospheric conditions for RAOBs.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9640E..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9640E..08S"><span>Performance test of the synergetic use of simulated lidar and <span class="hlt">microwave</span> <span class="hlt">radiometer</span> observations for mixing-layer height detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saeed, Umar; Rocadenbosch, Francesc; Crewell, Susanne</p> <p>2015-10-01</p> <p>There are several instruments and methods to retrieve the atmospheric Mixing Layer Height (MLH). However, none of these instruments or methods can measure the development of the MLH under all atmospheric conditions. For example, aerosol signatures measured by backscatter lidars can be used to determine the MLH but this approach is reasonable only when the atmosphere is well-mixed. <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (MWR) derived profiles have low vertical resolution and cannot resolve fine structures in the boundary layer, especially, at higher altitudes. Here we propose a method which combines data from a ground-based lidar and a MWR, in simulated as well as real measurements scenarios, to overcome these limitations. The method works by fitting an erf-like transition model function to the section of range-corrected lidar backscatter signal. The section of the lidar backscatter signal for fitting the model function is obtained by incorporating the MWR estimates of MLH along with their uncertainties. The fitting is achieved by using an extended Kalman filter (EKF). The proposed approach, by exploiting the synergy between the two instruments, enables to detect MLH with original vertical and temporal resolutions. Test cases combining simulated data for a co-located lidar-ceilometer and a MWR are presented. The simulated data is obtained from the Dutch Atmospheric Large Eddy Simulation (DALES) model for boundary layer studies. Doppler wind lidar along with radiosondes (whenever available) data is used to assess the quality of the synergetic MLH estimates. Data from the HD(CP)2 Observational Prototype Experiment (HOPE) campaign at Jülich, Germany is used to test the proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C43D..02D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C43D..02D"><span>a Bayesian retrieval of Greenland ice sheet internal temperature from ultra-wideband software-defined <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (UWBRAD) measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duan, Y.; Durand, M. T.; Jezek, K. C.; Yardim, C.; Bringer, A.; Aksoy, M.; Johnson, J. T.</p> <p>2016-12-01</p> <p>The ultra-wideband software-defined <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (UWBRAD) is designed to provide ice sheet internal temperature product via measuring low frequency <span class="hlt">microwave</span> emission. Twelve channels ranging from 0.5 to 2.0 GHz are covered by the instrument. A four channel prototype of UWBRAD was completed and operated at Dome-C, Antarctic from a tower. A Greenland air-borne demonstration is scheduled for September 2016. A Bayesian framework is designed to retrieve the ice sheet internal temperature from simulated UWBRAD brightness temperature (Tb) measurements over Greenland flight path with limited prior information of the ground. A 1-D heat-flow model, the Robin Model, is used to model the ice sheet internal temperature profile with ground information. Synthetic UWBRAD Tbobservations was generated via the coherent radiation transfer model, which utilizes the Robin model temperature profile and an exponential fit of ice density from Borehole measurement as input, and corrupted with noise. The effective surface temperature, geothermal heat flux and the variance of upper layer ice density are treated as unknown variables within the retrieval framework. Each parameter is defined with its possible range and set to be uniformly distributed. The Markov Chain Monte Carlo (MCMC) approach is applied to make the unknown parameters randomly walk in the parameter space. We investigate whether the variables can be improved over priors using the MCMC approach and contribute to the temperature retrieval theoretically. Experiment results are examined for science goals on three levels: estimation of the 10-m firn temperature, the average temperature integrated with depth, and the entire temperature profile. With 47 points examined, the 10 m temperatures are all estimated within ± 1 K, and mostly within ± 0.5 K despite a consistent high correlation, over 0.75, between surface temperature and density variation is observed. The RMS error of the temperature estimates are all within 3.3 K</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/894832','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/894832"><span>Millimeter-wave <span class="hlt">Radiometer</span> for High Sensitivity <span class="hlt">Water</span> Vapor Profiling in Arid Regions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pazmany, Andrew</p> <p>2006-11-09</p> <p>Abstract - ProSensing Inc. has developed a G-band (183 GHz) <span class="hlt">water</span> Vapor <span class="hlt">Radiometer</span> (GVR) for long-term, unattended measurements of low concentrations of atmospheric <span class="hlt">water</span> vapor and liquid <span class="hlt">water</span>. Precipitable <span class="hlt">water</span> vapor and liquid <span class="hlt">water</span> path are estimated from zenith brightness temperatures measured from four double-sideband receiver channels, centered at 183.31 1, 3 and 7, and 14 GHz. A prototype ground-based version of the instrument was deployed at the DOE ARM program?s North Slope of Alaska site near Barrow AK in April 2005, where it collected data continuously for one year. A compact, airborne version of this instrument, packaged to operate from a standard 2-D PMS probe canister, has been tested on the ground and is scheduled for test flights in the summer of 2006. This paper presents design details, laboratory test results and examples of retrieved precipitable <span class="hlt">water</span> vapor and liquid <span class="hlt">water</span> path from measured brightness temperature data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780013629','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780013629"><span>Snow parameters from Nimbus-6 electrically scanned <span class="hlt">microwave</span> <span class="hlt">radiometer</span>. [(ESMR-6)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abrams, G.; Edgerton, A. T.</p> <p>1977-01-01</p> <p>Two sites in Canada were selected for detailed analysis of the ESMR-6/ snow relationships. Data were analyzed for February 1976 for site 1 and January, February and March 1976 for site 2. Snowpack <span class="hlt">water</span> equivalents were less than 4.5 inches for site 1 and, depending on the month, were between 2.9 and 14.5 inches for site 2. A statistically significant relationship was found between ESMR-6 measurements and snowpack <span class="hlt">water</span> equivalents for the Site 2 February and March data. Associated analysis findings presented are the effects of random measurement errors, snow site physiolography, and weather conditions on the ESMR-6/snow relationship.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050180453','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050180453"><span>A Broadband <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Technique at X-band for Rain and Drop Size Distribution Estimation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Meneghini, R.</p> <p>2005-01-01</p> <p>Radiometric brightess temperatures below about 12 GHz provide accurate estimates of path attenuation through precipitation and cloud <span class="hlt">water</span>. Multiple brightness temperature measurements at X-band frequencies can be used to estimate rainfall rate and parameters of the drop size distribution once correction for cloud <span class="hlt">water</span> attenuation is made. Employing a stratiform storm model, calculations of the brightness temperatures at 9.5, 10 and 12 GHz are used to simulate estimates of path-averaged median mass diameter, number concentration and rainfall rate. The results indicate that reasonably accurate estimates of rainfall rate and information on the drop size distribution can be derived over ocean under low to moderate wind speed conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=266167','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=266167"><span>Soil moisture retrievals from the WindSat spaceborne polarimetric <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Surface soil moisture plays an important role in many <span class="hlt">water</span>- and energy-balanced related studies. It is an important parameter in several applications, such as numerical weather predictions, global change modelling, forecasting of surface runoff and modelling of evaporation. Soil moisture is conside...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JGRD..11115209D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JGRD..11115209D"><span>New dual-frequency <span class="hlt">microwave</span> technique for retrieving liquid <span class="hlt">water</span> path over land</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deeter, M. N.; Vivekanandan, J.</p> <p>2006-08-01</p> <p>We present and demonstrate a new methodology for retrieving liquid <span class="hlt">water</span> path over land using satellite-based <span class="hlt">microwave</span> observations. As input, the technique exploits Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> for EOS (AMSR-E) brightness temperature polarization-difference signals at 37 and 89 GHz. Regression analysis performed on model simulations indicates that over variable atmospheric and surface conditions these polarization-difference signals can be simply parameterized in terms of the surface emissivity polarization-difference (Δɛ), surface temperature, liquid <span class="hlt">water</span> path (LWP), and precipitable <span class="hlt">water</span> vapor (PWV). By exploiting the weak frequency dependence of Δɛ, a simple expression is obtained which enables fast and direct (noniterative) retrievals of LWP. The new methodology is demonstrated and validated using several months of AMSR-E observations over (1) the Southern Great Plains (SGP) of the United States and (2) an area near Montreal, Canada, instrumented during the Alliance Icing Research Study II (AIRS II) field campaign. Comparisons are also made with MODIS LWP retrieval results for one scene over the SGP region. Retrieval results in clear-sky conditions indicate an uncertainty on the order of 0.06 mm, in agreement with theoretical estimates. In cloudy conditions, results using the new method are systematically smaller than results for both ground-based <span class="hlt">microwave</span> <span class="hlt">radiometers</span> and MODIS but are well correlated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AMT.....9.4587N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AMT.....9.4587N"><span>Validation of brightness and physical temperature from two scanning <span class="hlt">microwave</span> <span class="hlt">radiometers</span> in the 60 GHz O2 band using radiosonde measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Navas-Guzmán, Francisco; Kämpfer, Niklaus; Haefele, Alexander</p> <p>2016-09-01</p> <p>In this paper, we address the assessment of the tropospheric performance of a new temperature <span class="hlt">radiometer</span> (TEMPERA) at 60 GHz. With this goal, an intercomparison campaign was carried out at the aerological station of MeteoSwiss in Payerne (Switzerland). The brightness temperature and the tropospheric temperature were assessed by means of a comparison with simultaneous and collocated radiosondes that are launched twice a day at this station. In addition, the TEMPERA performances are compared with the ones from a commercial <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (HATPRO), which has some different instrumental characteristics and uses a different inversion algorithm. Brightness temperatures from both <span class="hlt">radiometers</span> were compared with the ones simulated using a radiative transfer model and atmospheric profiles from radiosondes. A total of 532 cases were analyzed under all weather conditions and evidenced larger brightness temperature deviations between the two <span class="hlt">radiometers</span> and the radiosondes for the most transparent channels. Two different retrievals for the TEMPERA <span class="hlt">radiometer</span> were implemented in order to evaluate the effect of the different channels on the temperature retrievals. The comparison with radiosondes evidenced better results very similar to the ones from HATPRO, when the eight more opaque channels were used. The study shows the good performance of TEMPERA to retrieve temperature profiles in the troposphere. The inversion method of TEMPERA is based on the optimal estimation method. The main advantage of this algorithm is that there is no necessity for radiosonde information to achieve good results in contrast to conventional methods as neural networks or lineal regression. Finally, an assessment of the effect of instrumental characteristics as the filter response and the antenna pattern on the brightness temperature showed that they can have an important impact on the most transparent channels.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009GeoRL..36.6803C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009GeoRL..36.6803C"><span>Can liquid <span class="hlt">water</span> profiles be retrieved from passive <span class="hlt">microwave</span> zenith observations?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crewell, Susanne; Ebell, Kerstin; Löhnert, Ulrich; Turner, D. D.</p> <p>2009-03-01</p> <p>The ability to determine the cloud boundaries and vertical distribution of cloud liquid <span class="hlt">water</span> for single-layer liquid clouds using zenith-pointing <span class="hlt">microwave</span> <span class="hlt">radiometers</span> is investigated. Simulations are used to demonstrate that there is little skill in determining either cloud base or cloud thickness, especially when the cloud thickness is less than 500 m. It is also shown that the different distributions of liquid <span class="hlt">water</span> content within a cloud with known cloud boundaries results in a maximum change in the brightness temperature of less than 1 K at the surface from 20 to 150 GHz, which is on the order of the instrument noise level. Furthermore, it is demonstrated using the averaging kernel that the number of degrees of freedom for signal (i.e., independent pieces of information) is approximately 1, which implies there is no information on vertical distribution of liquid <span class="hlt">water</span> in the <span class="hlt">microwave</span> observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IPNPR.203A...1M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IPNPR.203A...1M"><span>A Statistical Comparison of Meteorological Data Types Derived from Deep Space Network <span class="hlt">Water</span> Vapor <span class="hlt">Radiometers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morabito, D. D.; Keihm, S.; Slobin, S.</p> <p>2015-11-01</p> <p><span class="hlt">Water</span> vapor <span class="hlt">radiometers</span> measure the sky brightness along a path through the atmosphere. This sky brightness is a combination of the atmospheric "noise" temperature and the cosmic background. By removing the cosmic contribution, the remaining atmospheric noise temperature contribution can be used to infer atmospheric attenuation and atmospheric noise temperature used in telecommunications link budgets. <span class="hlt">Water</span> vapor <span class="hlt">radiometer</span> (WVR) data also have been used to calibrate or experimentally characterize atmospheric error sources in phase data gathered from radio science and very long baseline interferometry (VLBI) experiments. A previous article reported on the comparison of atmospheric attenuation derived from WVR data with that estimated from International Telecommunication Union (ITU) models for the three Deep Space Network (DSN) sites. The focus of this current article is to examine and cross-compare the statistics of the meteorological data types (integrated precipitable <span class="hlt">water</span> vapor, integrated liquid <span class="hlt">water</span> content, and wet path delay) extracted from the WVR measurements for all three DSN sites. In this article, we will also compare some of the statistical estimates against those available using ITU models and prediction methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002SPIE.4815...36N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002SPIE.4815...36N"><span>Measurements of atmospheric <span class="hlt">water</span> vapor above Mauna Kea using an infrared <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Naylor, David A.; Chapman, Ian M.; Gom, Bradley G.</p> <p>2002-09-01</p> <p>Astronomical arrays operating at (sub)millimeter wavelengths are seriously compromised by rapid variations in atmospheric <span class="hlt">water</span> vapor that distort the phase coherence of incoming celestial signals. The signal received by each antenna of the array suffers a phase delay that varies rapidly with time and from antenna to antenna. Unless corrected, these distortions limit the coherence time of the array and seriously compromise its sensitivity and image quality. Building on the success of a prototype infrared <span class="hlt">radiometer</span> for millimeter astronomy (IRMA), which operates in the 20 micrometers region to measure the column abundance of atmospheric <span class="hlt">water</span> vapor, this paper presents results obtained with a second generation IRMA operating at the James Clerk Maxwell telescope (JCMT) between January and July 2001. The results are compared with other measures of <span class="hlt">water</span> vapor available on the summit of Mauna Kea, including: the JCMT SCUBA bolometer camera, the California Institute of Technology (CSO) opacity monitors, the JCMT 183GHz <span class="hlt">water</span> vapor <span class="hlt">radiometer</span> and Hilo-launched radiosonde data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E2730R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E2730R"><span>Comparison of Relative Humidity obtained from SAPHIR on board Megha-Tropiques and Ground based <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Profiler over an equatorial station</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Renju, Ramachandran Pillai; Uma, K. N.; Krishna Moorthy, K.; Mathew, Nizy; Raju C, Suresh</p> <p></p> <p>A comparison has been made between the SAPHIR on board Megha-Tropiques (MT) derived Relative Humidity (RH (%)) with that derived from a ground based multi-frequency <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> Profiler (MRP) observations over an equatorial station Thiruvananthapuram (8.5(°) N and 76.9(°) E) for a one year period. As a first step, the validation of MRP has been made against the radiosonde for two years (2010 and 2011) during the Indian monsoon period July-September. This analysis shows a wet bias below 6 km and dry bias above. The comparison between the MRP and the MT derived RH has been made at five different altitudinal levels (0.75, 2.25, 4.0, 6.25 and 9.2 km range) strictly under clear sky condition. The regression analysis between the two reveals very good correlation (>0.8) in the altitudinal layer of 2.25 to 6.25 km. The differences between the two observations had also been explained interms of percentage of occurrence between MT and the MRP at each altitudinal layer. About 70-80% of the time, the difference in the RH is found to below 10% at first three layer. The RMSE of 2% is observed at almost all the height layers. The differences have been attributed to the different measurement and retrieval techniques involved in the ground based and satellite based measurements. Since MRP frequecy channels are not sensitive to small <span class="hlt">water</span> vapor variabilities above 6 km, large differences are observed. Radiative Transfer computation for the channels of both MRP and SAPHIR will be carried out to understand the variabilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AMTD....5.3117E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AMTD....5.3117E"><span>Ice hydrometeor profile retrieval algorithm for high frequency <span class="hlt">microwave</span> <span class="hlt">radiometers</span>: application to the CoSSIR instrument during TC4</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Evans, K. F.; Wang, J. R.; O'C Starr, D.; Heymsfield, G.; Li, L.; Tian, L.; Lawson, R. P.; Heymsfield, A. J.; Bansemer, A.</p> <p>2012-04-01</p> <p>A Bayesian algorithm to retrieve profiles of cloud ice <span class="hlt">water</span> content (IWC), ice particle size (Dme), and relative humidity from millimeter-wave/submillimeter-wave <span class="hlt">radiometers</span> is presented. The first part of the algorithm prepares an a priori file with cumulative distribution functions (CDFs) and empirical orthogonal functions (EOFs) of profiles of temperature, relative humidity, three ice particle parameters (IWC, Dme, distribution width), and two liquid cloud parameters. The a priori CDFs and EOFs are derived from CloudSat radar reflectivity profiles and associated ECMWF temperature and relative humidity profiles combined with three cloud microphysical probability distributions obtained from in situ cloud probes. The second part of the algorithm uses the CDF/EOF file to perform a Bayesian retrieval with a hybrid technique that uses Monte Carlo integration (MCI) or, when too few MCI cases match the observations, uses optimization to maximize the posterior probability function. The very computationally intensive Markov chain Monte Carlo (MCMC) method also may be chosen as a solution method. The radiative transfer model assumes mixtures of several shapes of randomly oriented ice particles, and here random aggregates of hexagonal plates, spheres, and dendrites are used for tropical convection. A new physical model of stochastic dendritic snowflake aggregation is developed. The retrieval algorithm is applied to data from the Compact Scanning Submillimeter-wave Imaging <span class="hlt">Radiometer</span> (CoSSIR) flown on the ER-2 aircraft during the Tropical Composition, Cloud and Climate Coupling (TC4) experiment in 2007. Example retrievals with error bars are shown for nadir profiles of IWC, Dme, and relative humidity, and nadir and conical scan swath retrievals of ice <span class="hlt">water</span> path and average Dme. The ice cloud retrievals are evaluated by retrieving integrated 94 GHz backscattering from CoSSIR for comparison with the Cloud Radar System (CRS) flown on the same aircraft. The rms difference in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930010900','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930010900"><span>Airborne full polarization radiometry using the MSFC Advanced <span class="hlt">Microwave</span> Precipitation <span class="hlt">Radiometer</span> (AMPR)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gasiewski, Al J.; Kunkee, D. B.</p> <p>1993-01-01</p> <p>The applications of vertically and horizontally polarized brightness temperatures in both atmospheric and surface remote sensing have been long recognized by many investigators, particularly those studying SMMR and SSM/I data. Here, the large contrast between the first two Stokes' parameters (T(sub V) and T(sub H)) can be used for detection of sea ice, measurement of ocean surface wind speed, and measurement of cloud and <span class="hlt">water</span> vapor opacity. High-resolution aircraft data from instruments such as the NASA/MSFC AMPR is crucial for verifying radiative transfer models and developing retrieval algorithms. Currently, the AMPR is outfitted with single-polarization channels at 10, 18, 37 and 85 GHz. To increase its utility, it is proposed that additional orthogonal linearly polarized channels be added to the AMPR. Since the AMPR's feedhorns are already configured for dual orthogonal linearly polarized modes, this would require only a duplication of the currently existing receivers. To circumvent the resulting polarization basis skew caused by the cross-track scanning mechanism, the technique of Electronic Polarization Basis Rotation is proposed to be implemented. Implementation of EPBR requires precise measurement of the third Stokes parameter and will eliminate polarization skew by allowing the feedhorn basis skew angle to be corrected in software. In addition to upgrading AMPR to dual polarization capability (without skew), the modifications will provide an opportunity to demonstrate EPBR on an airborne platform. This is a highly desirable intermediate step prior to satellite implementation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810011961','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810011961"><span>Snow <span class="hlt">water</span> equivalent determination by <span class="hlt">microwave</span> radiometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, A. T. C.; Foster, J. L.; Hall, D. K.; Rango, A.; Hartline, B. K.</p> <p>1981-01-01</p> <p>One of the most important parameters for accurate snowmelt runoff prediction is snow <span class="hlt">water</span> equivalent (SWE) which is contentionally monitored using observations made at widely scattered points in or around specific watersheds. Remote sensors which provide data with better spatial and temporal coverage can be used to improve the SWE estimates. <span class="hlt">Microwave</span> radiation, which can penetrate through a snowpack, may be used to infer the SWE. Calculations made from a microscopic scattering model were used to simulate the effect of varying SWE on the <span class="hlt">microwave</span> brightness temperature. Data obtained from truck mounted, airborne and spaceborne systems from various test sites were studied. The simulated SWE compares favorable with the measured SWE. In addition, whether the underlying soil is frozen or thawed can be discriminated successfully on the basis of the polarization of the <span class="hlt">microwave</span> radiation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19760045119&hterms=DDR&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DDDR','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19760045119&hterms=DDR&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DDDR"><span>Evaluation of the dual differential <span class="hlt">radiometer</span> for remote sensing of sediment and chlorophyll in turbid <span class="hlt">waters</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Witte, W. G.</p> <p>1975-01-01</p> <p>The dual differential <span class="hlt">radiometer</span> (DDR) was tested to determine its capability for measuring suspended sediment and chlorophyll in turbid <span class="hlt">waters</span>. Measurements were obtained from a boat dock and from a helicopter with combinations of sample and reference filters with peak transmissions at various wavelengths. <span class="hlt">Water</span> samples were taken concurrently and were analyzed for light scattering, particle count, and total chlorophyll. Least-squares estimates of the linear relationship between DDR output and the <span class="hlt">water</span> parameters yielded correlation coefficients of less than 0.7. Under the turbid <span class="hlt">water</span> conditions of the present tests, the DDR did not accurately measure either suspended sediment or chlorophyll. A precise knowledge of the spectral signatures of various pollutants might enable appropriate filters to be selected for tuning the DDR to monitor a particular pollutant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ACP....1610455M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ACP....1610455M"><span>The natural oscillations in stratospheric ozone observed by the GROMOS <span class="hlt">microwave</span> <span class="hlt">radiometer</span> at the NDACC station Bern</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moreira, Lorena; Hocke, Klemens; Navas-Guzmán, Francisco; Eckert, Ellen; von Clarmann, Thomas; Kämpfer, Niklaus</p> <p>2016-08-01</p> <p>A multilinear parametric regression analysis was performed to assess the seasonal and interannual variations of stratospheric ozone profiles from the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) <span class="hlt">microwave</span> <span class="hlt">radiometer</span> at Bern, Switzerland (46.95° N, 7.44° E; 577 m). GROMOS takes part in the Network for the Detection of Atmospheric Composition Change (NDACC). The study covers the stratosphere from 50 to 0.5 hPa (from 21 to 53 km) and extends over the period from January 1997 to January 2015. The natural variability was fitted during the regression analysis through the annual and semi-annual oscillations (AO, SAO), the quasi-biennial oscillation (QBO), the El Niño-Southern Oscillation (ENSO) and the solar activity cycle. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the upper stratosphere. Regarding the interannual variations, they are primarily present in the lower and middle stratosphere. In the lower and middle stratosphere, ozone variations are controlled predominantly by transport processes, due to the long lifetime of ozone, whereas in the upper stratosphere its lifetime is relatively short and ozone is controlled mainly by photochemistry. The present study shows agreement in the observed naturally induced ozone signatures with other studies. Further, we present an overview of the possible causes of the effects observed in stratospheric ozone due to natural oscillations at a northern midlatitude station. For instance regarding the SAO, we find that polar winter stratopause warmings contribute to the strength of this oscillation since these temperature enhancements lead to a reduction in upper stratospheric ozone. We have detected a strong peak amplitude of about 5 % for the solar cycle in lower stratospheric ozone for our 1.5 cycles of solar activity. Though the 11-year ozone oscillation above Bern is in phase with the solar cycle, we suppose that the strong amplitude is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2802S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2802S"><span>Estimation of soil <span class="hlt">water</span> content in Mongolian grasslands using a spectral <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sekiyama, Ayako; Shimada, Sawahiko; Toyoda, Hiromichi; Yokohama, Michinari</p> <p></p> <p>Harsh winter conditions, called dzud, experienced in Mongolia in recent years have caused significant damage to their livestock. Grassland deterioration resulting from soil <span class="hlt">water</span> shortage coupled with the lack of precipitation during summer is one of the causative factors of this damage. Collecting grassland information over a wide area by satellite remote sensing is useful for spatial prediction of dzud. In this study, we conducted a fundamental experiment to estimate soil <span class="hlt">water</span> content using a spectral <span class="hlt">radiometer</span> (observed wavelength range, 302.9-1145.8 nm), which uses the same sensor as a satellite. Soil spectral reflectance was measured under open-air conditions using a spectral <span class="hlt">radiometer</span> at the experiment station. The soil <span class="hlt">water</span> content was controlled in several samples by adding <span class="hlt">water</span>, and the spectral reflectance of the sample surface was measured. Four spectral bands were selected under the observed wavelength for application to the satellite data. The soil spectral reflectance was normalized by the sum of the reflectance values of each band. It was found that a normalized soil reflectance pattern changed to a flat pattern with a decrease in soil <span class="hlt">water</span> content. Fujiwara et al. (1996) proposed a pattern decomposition method to decompose a mixed spectral reflectance pattern, e.g., land cover of soil and vegetation, into its respective parts. The decomposition coefficient for each pattern was calculated based on the mixed content of the reflectance patterns. In this study, a new spectral pattern, observed as a flat shape in the reflectance curve, was derived to extract the components of soil <span class="hlt">water</span> content. Pattern decomposition was conducted using soil and flat model patterns, and their decomposition coefficients were calculated. The correlation between soil <span class="hlt">water</span> content and the flat model pattern decomposition coefficient was calculated by regression analysis. To apply this method to field data, we conducted site investigations in Mongolian grasslands</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27879839','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27879839"><span>Temporal Variability Corrections for Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> E (AMSR-E) Surface Soil Moisture: Case Study in Little River Region, Georgia, U.S.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Choi, Minha; Jacobs, Jennifer M</p> <p>2008-04-14</p> <p>Statistical correction methods, the Cumulative Distribution Function (CDF) matching technique and Regional Statistics Method (RSM) are applied to adjust the limited temporal variability of Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> E (AMSR-E) data using the Common Land Model (CLM). The temporal variability adjustment between CLM and AMSR-E data was conducted for annual and seasonal periods for 2003 in the Little River region, GA. The results showed that the statistical correction techniques improved AMSR-E's limited temporal variability as compared to ground-based measurements. The regression slope and intercept improved from 0.210 and 0.112 up to 0.971 and -0.005 for the non-growing season. The R² values also modestly improved. The Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) products were able to identify periods having an attenuated <span class="hlt">microwave</span> brightness signal that are not likely to benefit from these statistical correction techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780025569','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780025569"><span>Remote sensing of atmospheric <span class="hlt">water</span> vapor, liquid <span class="hlt">water</span> and wind speed at the ocean surface by passive <span class="hlt">microwave</span> techniques from the Nimbus-5 satellite</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, A. T. C.; Wilheit, T. T.</p> <p>1977-01-01</p> <p>The <span class="hlt">microwave</span> brightness temperature measurements for Nimbus-5 electrically scanned <span class="hlt">microwave</span> <span class="hlt">radiometer</span> and Nimbus E <span class="hlt">microwave</span> spectrometer are used to retrieve the atmospheric <span class="hlt">water</span> vapor, liquid <span class="hlt">water</span> and wind speed by a quasi-statistical retrieval technique. It is shown that the brightness temperature can be utilized to yield these parameters under various weather conditions. Observations at 19.35 GHz, 22.235 GHz and 31.4 GHz were input to the regression equations. The retrieved values of these parameters for portions of two Nimbus-5 orbits are presented. Then comparison between the retrieved parameters and the available observations on the total <span class="hlt">water</span> vapor content and the surface wind speed are made. The estimated errors for retrieval are approximately 0.15 g/sq cm for <span class="hlt">water</span> vapor content, 6.5 mg/sq cm for liquid <span class="hlt">water</span> content and 6.6 m/sec for surface wind speed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900034627&hterms=Environmental+Justice&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DEnvironmental%2BJustice','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900034627&hterms=Environmental+Justice&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DEnvironmental%2BJustice"><span>Comparison of data from the Scanning Multifrequency <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) with data from the Advanced Very High Resolution <span class="hlt">Radiometer</span> (AVHRR) for terrestrial environmental monitoring - An overview</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Townshend, J. R. G.; Choudhury, B. J.; Tucker, C. J.; Giddings, L.; Justice, C. O.</p> <p>1989-01-01</p> <p>Comparison between the <span class="hlt">microwave</span> polarized difference temperature (MPDT) derived from 37 GHz band data and the normalized difference vegetation index (NDVI) derived from near-infrared and red bands, from several empirical investigations are summarized. These indicate the complementary character of the two measures in environmental monitoring. Overall the NDVI is more sensitive to green leaf activity, whereas the MPDT appears also to be related to other elements of the above-ground biomass. Monitoring of hydrological phenomena is carried out much more effectively by the MPDT. Further work is needed to explain spectral and temporal variation in MPDT both through modelling and field experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900034627&hterms=recursos&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drecursos','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900034627&hterms=recursos&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drecursos"><span>Comparison of data from the Scanning Multifrequency <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SMMR) with data from the Advanced Very High Resolution <span class="hlt">Radiometer</span> (AVHRR) for terrestrial environmental monitoring - An overview</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Townshend, J. R. G.; Choudhury, B. J.; Tucker, C. J.; Giddings, L.; Justice, C. O.</p> <p>1989-01-01</p> <p>Comparison between the <span class="hlt">microwave</span> polarized difference temperature (MPDT) derived from 37 GHz band data and the normalized difference vegetation index (NDVI) derived from near-infrared and red bands, from several empirical investigations are summarized. These indicate the complementary character of the two measures in environmental monitoring. Overall the NDVI is more sensitive to green leaf activity, whereas the MPDT appears also to be related to other elements of the above-ground biomass. Monitoring of hydrological phenomena is carried out much more effectively by the MPDT. Further work is needed to explain spectral and temporal variation in MPDT both through modelling and field experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.5552N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.5552N"><span>High time resolution observations of the polar stratosphere and mesosphere using a ground-based 230-250 GHz <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newnham, D. A.; Espy, P. J.; Clilverd, M. A.; Maxfield, D. J.; Hartogh, P.; Holmén, K.; Blindheim, S.; Horne, R. B.</p> <p>2012-04-01</p> <p><span class="hlt">Microwave</span> radiometry is used to measure thermal emission by the Doppler- and pressure-broadened molecular rotational lines of atmospheric gases, from which vertical abundance profiles can be determined. Since solar radiation is not required for the measurement, the technique has the advantage that continuous observations are possible including throughout the polar winter. We describe the development of a passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> [Espy, P. J., P. Hartogh, and K. Holmen (2006), Proc. SPIE, 6362, 63620P, doi:10.1117/12.688953] for ground-based remote sensing of the polar middle atmosphere. The instrument measures nitric oxide (NO), ozone (O3), and carbon monoxide (CO) vertical profiles over the altitude range 35-90 km with time resolution as high as 15 minutes, allowing the diurnal variability of trace chemical species to be investigated. Heterodyne detection of atmospheric emission at 230 GHz and 250 GHz (wavelength ~1.25 mm) with a receiver noise temperature of 300 K is achieved using a superconductor-insulator-superconductor (SIS) mixer cooled to 4 K. The down-converted signals at 1.35 GHz and 2.10 GHz are analysed using both a moderate-resolution (28 kHz, 220 MHz bandwidth) and a high-resolution (14 kHz, 40 MHz bandwidth) chirp-transform spectrometer (CTS). The instrument was operated semi-autonomously at Troll station (72° 01'S 02° 32'E, 1270 m above sea level), Antarctica during 2008-10 and at the Arctic LIDAR Observatory for Middle Atmosphere Research (ALOMAR, 69° 16'N, 16° 00'E, 380 m above sea level), northern Norway during 2011-12. NO volume mixing ratio (VMR) profiles have been inverted from calibrated brightness temperature spectra of the NO line centred at 250.796 GHz, observed above Troll station, using the <span class="hlt">Microwave</span> Observation Line Estimation and Retrieval (MOLIERE) version 5 code. A priori pressure, temperature, ozone, <span class="hlt">water</span> vapour, and NO profiles above 30 km were calculated using the Sodankylä Ion and Neutral Chemistry (SIC, version 6</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SPIE.4820..908N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SPIE.4820..908N"><span>Remotely operated infrared <span class="hlt">radiometer</span> for the measurement of atmospheric <span class="hlt">water</span> vapor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Naylor, David A.; Gom, Bradley G.; Schofield, Ian S.; Tompkins, Gregory J.; Chapman, Ian M.</p> <p>2003-01-01</p> <p>Astronomical arrays operating at (sub)millimeter wavelengths are seriously compromised by rapid variations in atmospheric <span class="hlt">water</span> vapor that distort the phase coherence of incoming celestial signals. The signal received by each antenna of the array suffers a phase delay that varies rapidly with time and from antenna to antenna. Unless corrected, these distortions limit the coherence time of the array and seriously compromise its sensitivity and image quality. Building on the success of a prototype infrared <span class="hlt">radiometer</span> for millimeter astronomy (IRMA), which operates in the 20μm region to measure the column abundance of atmospheric <span class="hlt">water</span> vapor, this paper describes the latest version of the IRMA concept, which has been developed for operation at Llano de Chajnantor, future site of the Atacama Large Millimeter Array (ALMA). Since there is presently limited infrastructure at the Chilean site the design must pay careful attention to all aspects of remote operation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140007334','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140007334"><span>Hurricane Imaging <span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cecil, Daniel J.; James, Mark W.; Roberts, J. Brent; Bisawas, Sayak K.; Jones, W. Linwood; Johnson, James; Farrar, Spencer; Sahawneh, Saleem; Ruf, Christopher S.; Morris, Mary; Black, Peter G.</p> <p>2014-01-01</p> <p>The Hurricane Imaging <span class="hlt">Radiometer</span> (HIRAD) is a synthetic thinned array passive <span class="hlt">microwave</span> <span class="hlt">radiometer</span> designed to allow retrieval of surface wind speed in hurricanes, up through category five intensity. The retrieval technology follows the Stepped Frequency <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (SFMR), which measures surface wind speed in hurricanes along a narrow strip beneath the aircraft. HIRAD has flown in the NASA Genesis and Rapid Intensification Processes (GRIP) experiement in 2010 on a WB-57 aircraft, and on a Global Hawk unmanned aircraft system (UAS) in 2012 and 2013 as part of NASA's Hurricane and Severe Storms Sentinel (HS3) program. The GRIP program included flights over Hurricanes Earl and Karl (2010). The 2012 HS3 deployment did not include any hurricane flights for the UAS carrying HIRAD. Hurricane flights are expected for HIRAD in 2013 during HS3. This presentation will describe the HIRAD instrument, its results from the 2010 hurricane flights, and hopefully results from hurricane flights in August and September 2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990JGR....9516673J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990JGR....9516673J"><span>Passive <span class="hlt">microwave</span> remote sensing of cloud liquid <span class="hlt">water</span> over land regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jones, Andrew S.; Vonder Haar, Thomas H.</p> <p>1990-09-01</p> <p>Techniques for cloud liquid <span class="hlt">water</span> retrieval over land are developed using data from the Special Sensor <span class="hlt">Microwave</span>/Imager 85.5 GHz (3.5 mm) channels. To minimize the effect of surface emittance variability on the calculations, the surface emittance was estimated with the aid of surface skin temperature retrievals from the Visible Infrared Spin Scan <span class="hlt">Radiometer</span> in geosynchronous orbit. The high sensitivity of the 85.5 GHz channels to cloud liquid <span class="hlt">water</span> allows for the estimation of integrated cloud liquid <span class="hlt">water</span> based on the <span class="hlt">microwave</span> brightness temperature depression caused by attenuation and emission of <span class="hlt">microwave</span> radiation at the colder ambient temperature of the cloud. The method assumes nonscattering radiative processes are dominant, therefore only nonprecipitating cloud liquid <span class="hlt">water</span> is considered. Integrated cloud liquid <span class="hlt">water</span> retrievals show good qualitative agreement with other available data sources. Numerical error sensitivity analysis show integrated cloud liquid <span class="hlt">water</span> error estimates of 0.05-0.50 kg m-2 depending on the contrast of cloud over background.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.A41H0163P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.A41H0163P"><span>TEMPEST-D MM-Wave <span class="hlt">Radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Padmanabhan, S.; Gaier, T.; Reising, S. C.; Lim, B.; Stachnik, R. A.; Jarnot, R.; Berg, W. K.; Kummerow, C. D.; Chandrasekar, V.</p> <p>2016-12-01</p> <p>The TEMPEST-D <span class="hlt">radiometer</span> is a five-frequency millimeter-wave <span class="hlt">radiometer</span> at 89, 165, 176, 180, and 182 GHz. The direct-detection architecture of the <span class="hlt">radiometer</span> reduces its power consumption and eliminates the need for a local oscillator, reducing complexity. The Instrument includes a blackbody calibrator and a scanning reflector, which enable precision calibration and cross-track scanning. The MMIC-based millimeter-wave <span class="hlt">radiometers</span> take advantage of the technology developed under extensive investment by the NASA Earth Science Technology Office (ESTO). The five-frequency millimeter-wave <span class="hlt">radiometer</span> is built by Jet Propulsion Laboratory (JPL), which has produced a number of state-of-the-art spaceborne <span class="hlt">microwave</span> <span class="hlt">radiometers</span>, such as the <span class="hlt">Microwave</span> Limb Sounder (MLS), Advanced <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (AMR) for Jason-2/OSTM, Jason-3, and the Juno <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (MWR). The TEMPEST-D Instrument design is based on a 165 to 182 GHz <span class="hlt">radiometer</span> design inherited from RACE and an 89 GHz receiver developed under the ESTO ACT-08 and IIP-10 programs at Colorado State University (CSU) and JPL. The TEMPEST reflector scan and calibration methodology is adapted from the Advanced Technology <span class="hlt">Microwave</span> Sounder (ATMS) and has been validated on the Global Hawk unmanned aerial vehicle (UAV) using the High Altitude MMIC Sounding <span class="hlt">radiometer</span> (HAMSR) instrument. This presentation will focus on the design, development and performance of the TEMPEST-D <span class="hlt">radiometer</span> instrument. The flow-down of the TEMPEST-D mission objectives to instrument level requirements will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=214637','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=214637"><span>Remote Sensing Observatory Validation of Surface Soil Moisture Using Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> E, Common Land Model, and Ground Based Data: Case Study in SMEX03 Little River Region, Georgia, U.S.</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Optimal soil moisture estimation may be characterized by inter-comparisons among remotely sensed measurements, ground-based measurements, and land surface models. In this study, we compared soil moisture from Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> E (AMSR-E), ground-based measurements, and Soil-Vege...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800050110&hterms=water+speed&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwater%2Bspeed','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800050110&hterms=water+speed&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwater%2Bspeed"><span>Remote sensing of atmospheric <span class="hlt">water</span> vapor, liquid <span class="hlt">water</span>, and wind speed at the ocean surface by passive <span class="hlt">microwave</span> techniques from the Nimbus 5 satellite</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, A. T. C.; Wilheit, T. T.</p> <p>1979-01-01</p> <p>The <span class="hlt">microwave</span> brightness temperature measurements for Nimbus 5 electrically scanned <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (ESMR) and Nimbus-E <span class="hlt">microwave</span> spectrometer (NEMS) are used to retrieve the atmospheric <span class="hlt">water</span> vapor, liquid <span class="hlt">water</span>, and wind speed by a quasi-statistical retrieval technique. It is shown that the brightness temperature can be utilized to yield these parameters under various weather conditions. Observations at 19.35, 22.235, and 31.4 GHz were input to the regression equations. The retrieved values of these parameters for portions of two Nimbus 5 orbits are presented. Then comparison between the retrieved parameters and the available observations on the total <span class="hlt">water</span> vapor content and the surface wind speed are made.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ACP....12.7753S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ACP....12.7753S"><span>Observations of middle atmospheric H2O and O3 during the 2010 major sudden stratospheric warming by a network of <span class="hlt">microwave</span> <span class="hlt">radiometers</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scheiben, D.; Straub, C.; Hocke, K.; Forkman, P.; Kämpfer, N.</p> <p>2012-08-01</p> <p>In this study, we present middle atmospheric <span class="hlt">water</span> vapor (H2O) and ozone (O3) measurements obtained by ground-based <span class="hlt">microwave</span> <span class="hlt">radiometers</span> at three European locations in Bern (47° N), Onsala (57° N) and Sodankylä (67° N) during Northern winter 2009/2010. In January 2010, a major sudden stratospheric warming (SSW) occurred in the Northern Hemisphere whose signatures are evident in the ground-based observations of H2O and O3. The observed anomalies in H2O and O3 are mostly explained by the relative location of the polar vortex with respect to the measurement locations. The SSW started on 26 January 2010 and was most pronounced by the end of January. The zonal mean temperature in the middle stratosphere (10 hPa) increased by approximately 25 Kelvin within a few days. The stratospheric vortex weakened during the SSW and shifted towards Europe. In the mesosphere, the vortex broke down, which lead to large scale mixing of polar and midlatitudinal air. After the warming, the polar vortex in the stratosphere split into two weaker vortices and in the mesosphere, a new, pole-centered vortex formed with maximum wind speed of 70 m s-1 at approximately 40° N. The shift of the stratospheric vortex towards Europe was observed in Bern as an increase in stratospheric H2O and a decrease in O3. The breakdown of the mesospheric vortex during the SSW was observed at Onsala and Sodankylä as a sudden increase in mesospheric H2O. The following large-scale descent inside the newly formed mesospheric vortex was well captured by the H2O observations in Sodankylä. In order to combine the H2O observations from the three different locations, we applied the trajectory mapping technique on our H2O observations to derive synoptic scale maps of the H2O distribution. Based on our observations and the 3-D wind field, this method allows determining the approximate development of the stratospheric and mesospheric polar vortex and demonstrates the potential of a network of ground-based instruments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.C42B..04D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.C42B..04D"><span>Assessing Scale Effects on Snow <span class="hlt">Water</span> Equivalent Retrievals Using Airborne and Spaceborne Passive <span class="hlt">Microwave</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Derksen, C.; Walker, A.; Goodison, B.</p> <p>2003-12-01</p> <p>The Climate Research Branch (CRB) of the Meteorological Service of Canada (MSC) has a long-standing research program focused on the development of methods to retrieve snow cover information from passive <span class="hlt">microwave</span> satellite data for Canadian regions. Algorithms that derive snow <span class="hlt">water</span> equivalent (SWE) have been developed by CRB and are used to operationally generate SWE information over landscape regions including prairie, boreal forest, and taiga. New multi-scale research datasets were acquired in Saskatchewan, Canada during February 2003 to quantify the impact of spatially heterogeneous land cover and snowpack properties on passive <span class="hlt">microwave</span> SWE retrievals. MSC <span class="hlt">microwave</span> <span class="hlt">radiometers</span> (6.9, 19, 37, and 85 GHz) were flown on the National Research Council (NRC) Twin Otter aircraft at two flying heights along a grid of flight lines, covering a 25 by 25 km study area centered on the Old Jack Pine Boreal Ecosystem Research and Monitoring Site (BERMS). Spaceborne Special Sensor <span class="hlt">Microwave</span>/Imager (SSM/I) and Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> (AMSR-E) brightness temperatures were also acquired for this region. SWE was derived for all passive <span class="hlt">microwave</span> datasets using the CRB land cover sensitive algorithm suite. An intensive, coincident ground sampling program characterized in situ snow depth, density, <span class="hlt">water</span> equivalent and pack structure using a land cover based sampling scheme to isolate the variability in snow cover parameters within and between forest stands and land cover types, and within a single spaceborne passive <span class="hlt">microwave</span> grid cell. The passive <span class="hlt">microwave</span> data sets that are the focus of this investigation cover a range of spatial resolutions from 100-150 m for the airborne data to 10 km (AMSR-E) and 25 km (SSM/I) for the satellite data, providing the opportunity to investigate and compare <span class="hlt">microwave</span> emission characteristics, SWE retrievals and land cover effects at different spatial scales. Initial analysis shows that the small footprint airborne passive <span class="hlt">microwave</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JARS....5a3558L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JARS....5a3558L"><span>Retrieval of columnar <span class="hlt">water</span> vapor using multispectral <span class="hlt">radiometer</span> measurements over northern China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Chaoshun; Li, Yun; Gao, Wei; Shi, Runhe; Bai, Kaixu</p> <p>2011-01-01</p> <p><span class="hlt">Water</span> vapor is an important component in hydrological processes that basically involve all types of seasons, including dry (e.g., drought) or wet (e.g., hurricane or monsoon). This study retrieved columnar <span class="hlt">water</span> vapor (CWV) with the 939.3 nm band of a multifilter rotating shadowband <span class="hlt">radiometer</span> (MFRSR) using the modified Langley technique. Such an investigation was in concert with the use of the atmospheric transmission model MODTRAN for determining the instrument coefficients required for CWV estimation. Results of the retrieval of CWV by MFRSR from September 23, 2004 to June 20, 2005 at the XiangHe site are presented and analyzed in this paper. To improve the credibility, the MFRSR results were compared with those obtained from the AErosol RObotic NETwork CIMEL sun-photometer measurements, co-located at the XiangHe site, and the moderate resolution imaging spectroradiometer (MODIS) near-infrared total precipitable <span class="hlt">water</span> product (MOD05), respectively. These comparisons show good agreement in terms of correlation coefficients, slopes, and offsets, revealing that the accuracy of CWV estimation using the MFRSR instrument is reliable and suitable for extended studies in northern China.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8523E..13S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8523E..13S"><span>Modeling of tropospheric integrated <span class="hlt">water</span> vapor content using GPS, radiosonde, <span class="hlt">radiometer</span>, rain gauge, and surface meteorological data in a tropical region (French Polynesia)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Serafini, Jonathan; Barriot, Jean-Pierre; Hopuare, Marania; Sichoix, Lydie; Fadil, Abdelali</p> <p>2012-11-01</p> <p>The integrated precipitable <span class="hlt">water</span> vapor (IPW) is characterized by strong spatial and temporal variability, especially over tropical regions where the troposhere is not purely in hydrostatic equilibrium (convection). As an evidence, the survey of <span class="hlt">water</span> vapor distibution as permanently as possible is an important issue and should serve as inputs for tropical climate modelling. In this paper, we present an estimation of the IPV from ground­ ba,.sed GPS receivers, which we compare to radiosondes and <span class="hlt">microwave</span> <span class="hlt">radiometer</span>. The data used here were collected in the vicinity of French Polynesia University site, during eight years from 2001 to 2008. In addition, we also include the IPW calculated using Era-Interim reanalyses (ECMWF). The main purpose of this paper is to highlight precision, qualities and limitations of each method available on the Island of Tahiti. During wet periods, the radiosondes vertical profiles of <span class="hlt">water</span> vapor show an efficient mixing of <span class="hlt">water</span> vapor between the the boundary layer (below trade winds inversion at Tahiti) and the free troposphere. Thus the rainy event detection allows to better constrain the validity range of a model of the vertical distribution of <span class="hlt">water</span> vapor, which is based on a pseudo-adiabatic saturated evolution of the temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/841634','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/841634"><span>New Technique for Retrieving Liquid <span class="hlt">Water</span> Path over Land using Satellite <span class="hlt">Microwave</span> Observations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Deeter, M.N.; Vivekanandan, J.</p> <p>2005-03-18</p> <p>We present a new methodology for retrieving liquid <span class="hlt">water</span> path over land using satellite <span class="hlt">microwave</span> observations. As input, the technique exploits the Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> for earth observing plan (EOS) (AMSR-E) polarization-difference signals at 37 and 89 GHz. Regression analysis performed on model simulations indicates that over variable atmospheric and surface conditions the polarization-difference signals can be simply parameterized in terms of the surface emissivity polarization difference ({Delta}{var_epsilon}), surface temperature, liquid <span class="hlt">water</span> path (LWP), and precipitable <span class="hlt">water</span> vapor (PWV). The resulting polarization-difference parameterization (PDP) enables fast and direct (noniterative) retrievals of LWP with minimal requirements for ancillary data. Single- and dual-channel retrieval methods are described and demonstrated. Data gridding is used to reduce the effects of instrumental noise. The methodology is demonstrated using AMSR-E observations over the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site during a six day period in November and December, 2003. Single- and dual-channel retrieval results mostly agree with ground-based <span class="hlt">microwave</span> retrievals of LWP to within approximately 0.04 mm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100003168','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100003168"><span>Solutions Network Formulation Report. Visible/Infrared Imager/<span class="hlt">Radiometer</span> Suite and Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> Data Products for National Drought Monitor Decision Support</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Estep, Leland</p> <p>2007-01-01</p> <p>Drought effects are either direct or indirect depending on location, population, and regional economic vitality. Common direct effects of drought are reduced crop, rangeland, and forest productivity; increased fire hazard; reduced <span class="hlt">water</span> levels; increased livestock and wildlife mortality rates; and damage to wildlife and fish habitat. Indirect impacts follow on the heels of direct impacts. For example, a reduction in crop, rangeland, and forest productivity may result in reduced income for farmers and agribusiness, increased prices for food and timber, unemployment, reduced tax revenues, increased crime, foreclosures on bank loans to farmers and businesses, migration, and disaster relief programs. In the United States alone, drought is estimated to result in annual losses of between $6 - 8 billion. Recent sustained drought in the United States has made decision-makers aware of the impacts of climate change on society and environment. The eight major droughts that occurred in the United States between 1980 and 1999 accounted for the largest percentage of weather-related monetary losses. Monitoring drought and its impact that occurs at a variety of scales is an important government activity -- not only nationally but internationally as well. The NDMC (National Drought Mitigation Center) and the USDA (U.S. Department of Agriculture) RMA (Risk Management Agency) have partnered together to develop a DM-DSS (Drought Monitoring Decision Support System). This monitoring system will be an interactive portal that will provide users the ability to visualize and assess drought at all levels. This candidate solution incorporates atmospherically corrected VIIRS data products, such as NDVI (Normalized Difference Vegetation Index) and Ocean SST (sea surface temperature), and AMSR-E soil moisture data products into two NDMC vegetation indices -- VegDRI (Vegetation Drought Response Index) and VegOUT (Vegetation Outlook) -- which are then input into the DM-DSS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900047899&hterms=Water+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWater%2Blaw','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900047899&hterms=Water+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWater%2Blaw"><span>Wave number spectra from temperature-humidity infrared <span class="hlt">radiometer</span> 6.7-micron <span class="hlt">water</span> vapor data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Manney, Gloria L.; Stanford, John L.</p> <p>1990-01-01</p> <p>Wave number spectra from Nimbus 7 temperature-humidity infrared <span class="hlt">radiometer</span> 6.7-micron <span class="hlt">water</span> vapor data are analyzed using series 4800 km long, in regions free of high clouds and frontal zones. In these regions, the brightness temperatures approximate temperatures on a <span class="hlt">water</span> vapor isosteric (constant density) surface, rather than averages over a broad vertical layer. Power above the noise can be extracted down to wavelengths of about 60 km. Fitting the power spectrum versus horizontal wave number k to a k to the -nth power law for wavelengths from 60 to a few hundred kilometers gives slopes of n = 2.7 to 3.0, depending on the exact wave numbers that are fitted. Thunderstorms and convective cloud systems may constitute an energy source for the reverse energy cascade which produces a -5/3 spectral slope. The results suggest that when these features are not present, the enstrophy-cascading process that gives a -3 slope may govern the motion at scales smaller than it has heretofore been observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/175904','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/175904"><span><span class="hlt">Microwave</span> treatment of industrial waste <span class="hlt">water</span> sludge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Goodwill, J.E.</p> <p>1995-12-31</p> <p>Steel mills in the US generate approximately 1 million tons of sludge annually. This is mainly a residue of cooling <span class="hlt">water</span>, lubricating oils, and metallic fines from hot strip rolling mills and other operations. At present the separation of sludge from the liquid requires large settling tanks, takes several hours of time, and produces a residue that must be disposed of at high cost. The EPRI Center for Materials Production, sponsored by the Electric Power Research Institute (EPRI), has supported development of a <span class="hlt">microwave</span> based treatment system. This new process, developed by Carnegie Mellon Research Institute of Carnegie Mellon University, and patented by EPRI is 30 times faster, requires 90% less space, and eliminates land-filling by producing materials of value. Electricity usage is only 0.5 kWh per gallon. A review by the American Iron and Steel Institute (AISI) Waste Recycle Technology Task Force of this and various other approaches, concluded that further work on the <span class="hlt">microwave</span> technology was justified. Subsequently additional work was undertaken toward optimizing the process for treating metallic waste sludges containing lime and polymers. This effort cofunded by EPRI and the AISI was successfully concluded in late 1994. Next a two phase program is being developed to commercialize the process. Phase 1 will demonstrate the technology in a large scale batch mode. Phase 2 will be a commercial scale continuous installation at a steel mill site projected for 1996.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810015969','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810015969"><span>Remote sensing of precipitable <span class="hlt">water</span> over the oceans from Nimbus-7 <span class="hlt">microwave</span> measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Prabhakara, C.; Change, H. D.; Chang, A. T. C.</p> <p>1981-01-01</p> <p>Global maps of precipitable <span class="hlt">water</span> over derived from scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (SMMR) data reveal salient features associated with ocean currents and the large scale general circulation in the atmosphere. Nimbus-7 SMMR brightness temperature measurements in the 21 and 18 GHz channels are used to sense the precipitable <span class="hlt">water</span> in the atmospheric over oceans. The difference in the brightness temperature (T sub 21 -T sub 18), both in the horizontal and vertical polarization, is found to be essentially a function of the precipitable <span class="hlt">water</span> in the atmosphere. An equation, based on the physical consideration of the radiative transfer in the <span class="hlt">microwave</span> region, is developed to relate the precipitable <span class="hlt">water</span> to (T sub 21 - T sub 18). It shows that the signal (T sub 21- T sub 18) does not suffer severely from the noise introduced by variations in the sea surface temperature, surface winds, and liquid <span class="hlt">water</span> content in non rain clouds. The rms deviation between the estimated precipitable <span class="hlt">water</span> from SMMR data and that given by the closely coincident ship radiosondes is about 0.25 g/ sq cm</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/166792','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/166792"><span>Comparison of ClO measurements by airborne and spaceborne <span class="hlt">microwave</span> <span class="hlt">radiometers</span> in the Arctic winter stratosphere 1993</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Crewell, S.; Fabian, R.; Kuenzi, K.</p> <p>1995-06-15</p> <p>In February 1993 measurements of chlorine monoxide ClO, one of the key substances in catalytic ozone destruction, were performed over Scandinavia by two <span class="hlt">microwave</span> receivers, the Submillimeter Atmospheric Sounder (SUMAS) on board the German research aircraft FALCON and the <span class="hlt">Microwave</span> Limb Sounder (MLS) on board the Upper Atmospheric Research Satellite (UARS). High ClO concentrations (>1 ppb) inside the polar vortex at approximately 20km altitude were detected by both experiments. A comparison shows good agreement of both sensors in the location of enhanced ClO. 11 refs., 5 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930047412&hterms=measure+temperature+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmeasure%2Btemperature%2Bwater','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930047412&hterms=measure+temperature+water&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmeasure%2Btemperature%2Bwater"><span>Ground-based <span class="hlt">microwave</span> remote sensing of <span class="hlt">water</span> vapor in the mesosphere and stratosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Croskey, Charles L.; Olivero, John J.; Martone, Joseph P.</p> <p>1991-01-01</p> <p>A ground-based, portable <span class="hlt">microwave</span> <span class="hlt">radiometer</span> that will be used to measure <span class="hlt">water</span> vapor in the 30-80-km altitude region, and is to operate 24 hr a day, is described. The thermally excited 22.235-GHz rotational-transition line of <span class="hlt">water</span> vapor is employed. The emission from this region produces a signal with an apparent brightness temperature of the order 0.1 to 0.5 K. A steerable reflector is used to provide optimal viewing angles, depending on the geographic location and season. Periodic tipping curve scans by this reflector permit determination of the amount of tropospheric correction that is applied to the data. All local oscillators in the receiver are crystal-controlled so that narrow-band spectral analysis of the received line shape can be performed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960009473','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960009473"><span><span class="hlt">Water</span> vapor <span class="hlt">radiometer</span> measurements of the tropospheric delay fluctuations at Goldstone over a full year</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Keihm, S. J.</p> <p>1995-01-01</p> <p>One year of near-continuous <span class="hlt">water</span> vapor <span class="hlt">radiometer</span> (WVR) measurements at DSS 13 has provided a database for characterizing the Goldstone tropospheric delay properties in a statistical sense. The results have been expressed in terms of the Allan standard deviation of delay and compared to a previous model for Goldstone fluctuations and the specifications of the Cassini Gravitational Wave Experiment (GWE). The new WVR data indicate that average fluctuation levels at hour time scales or less are approximately 30 percent lower than the earlier Goldstone model predictions. At greater than 1 h time scales, the WVR indicated fluctuation levels are in closer agreement with the model, although noise floor limitations may be artificially raising the average WVR-derived atmospheric fluctuation levels at the longer time scales. When scaled to two-way Doppler tracking at 20 deg elevation, as will occur for the GWE, these results indicate that Goldstone winter tropospheric delay fluctuations will typically be a factor of 10 larger than the GWE requirements at 1000 s and a factor of 4 larger at 10,000 s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ChPhL..30f5204Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ChPhL..30f5204Y"><span>Hydrogen Generation from the Dissociation of <span class="hlt">Water</span> Using <span class="hlt">Microwave</span> Plasmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yong, Ho Jung; Soo Ouk, Jang; Hyun Jong, You</p> <p>2013-06-01</p> <p>Hydrogen is produced by direct dissociation of <span class="hlt">water</span> vapor, i.e., splitting <span class="hlt">water</span> molecules by the electrons in <span class="hlt">water</span> plasma at low pressure (<10-50 Torr) using <span class="hlt">microwave</span> plasma discharge. This condition generates a high electron temperature, which facilitates the direct dissociation of <span class="hlt">water</span> molecules. A <span class="hlt">microwave</span> plasma source is developed, utilizing the magnetron of a <span class="hlt">microwave</span> oven and a TE10 rectangular waveguide. The quantity of the generated hydrogen is measured using a residual gas analyzer. The electron density and temperature are measured by a Langmuir probe, and the neutral temperature is calculated from the OH line intensity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982prnc.rept.....F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982prnc.rept.....F"><span>Maser <span class="hlt">radiometer</span> for cosmic background radiation anisotropy measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fixsen, D. J.; Wilkinson, D. T.</p> <p>1982-06-01</p> <p>A maser amplifier was incorporated into a low noise <span class="hlt">radiometer</span> designed to measure large-scale anisotropy in the 3 deg K <span class="hlt">microwave</span> background radiation. To minimize emission by atmospheric <span class="hlt">water</span> vapor and oxygen, the <span class="hlt">radiometer</span> is flown in a small balloon to an altitude to 25 km. Three successful flights were made - two from Palestine, Texas and one from Sao Jose dos Campos, Brazil. Good sky coverage is important to the experiment. Data from the northern hemisphere flights has been edited and calibrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820022662','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820022662"><span>Maser <span class="hlt">radiometer</span> for cosmic background radiation anisotropy measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fixsen, D. J.; Wilkinson, D. T.</p> <p>1982-01-01</p> <p>A maser amplifier was incorporated into a low noise <span class="hlt">radiometer</span> designed to measure large-scale anisotropy in the 3 deg K <span class="hlt">microwave</span> background radiation. To minimize emission by atmospheric <span class="hlt">water</span> vapor and oxygen, the <span class="hlt">radiometer</span> is flown in a small balloon to an altitude to 25 km. Three successful flights were made - two from Palestine, Texas and one from Sao Jose dos Campos, Brazil. Good sky coverage is important to the experiment. Data from the northern hemisphere flights has been edited and calibrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740011870','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740011870"><span>Measurement of atmospheric precipitable <span class="hlt">water</span> using a solar <span class="hlt">radiometer</span>. [<span class="hlt">water</span> vapor absorption effects</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pitts, D. E.; Dillinger, A. E.; Mcallum, W. E.</p> <p>1974-01-01</p> <p>A technique is described and tested that allows the determination of atmospheric precipitable <span class="hlt">water</span> from two measurements of solar intensity: one in a <span class="hlt">water</span>-vapor absorption band and another in a nearby spectral region unaffected by <span class="hlt">water</span> vapor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22590984','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22590984"><span>The scientific base of heating <span class="hlt">water</span> by <span class="hlt">microwave</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Akdoğan, Ender; Çiftçi, Muharrem</p> <p>2016-03-25</p> <p>This article is based on the master thesis [4] related to our invention which was published in World Intellectual Property Organization (WO/2011/048506) as a <span class="hlt">microwave</span> <span class="hlt">water</span> heater. In the project, a prototype was produced to use <span class="hlt">microwave</span> in industrial heating. In order to produce the prototype, the most appropriate material kind for <span class="hlt">microwave-water</span> experiments was determined by a new energy loss rate calculation technique. This new energy loss calculation is a determinative factor for material permeability at <span class="hlt">microwave</span> frequency band (1-100 GHz). This experimental series aim to investigate the rationality of using <span class="hlt">microwave</span> in heating industry. Theoretically, heating <span class="hlt">water</span> by <span class="hlt">microwave</span> (with steady frequency 2.45 GHz) is analyzed from sub-molecular to Classical Mechanic results of heating. In the study, we examined Quantum Mechanical base of heating <span class="hlt">water</span> by <span class="hlt">microwave</span> experiments. As a result, we derived a Semi-Quantum Mechanical equation for <span class="hlt">microwave-water</span> interactions and thus, Wien displacement law can be derived to verify experimental observations by this equation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1722n0001A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1722n0001A"><span>The scientific base of heating <span class="hlt">water</span> by <span class="hlt">microwave</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akdoǧan, Ender; ćiftçi, Muharrem</p> <p>2016-03-01</p> <p>This article is based on the master thesis [4] related to our invention which was published in World Intellectual Property Organization (WO/2011/048506) as a <span class="hlt">microwave</span> <span class="hlt">water</span> heater. In the project, a prototype was produced to use <span class="hlt">microwave</span> in industrial heating. In order to produce the prototype, the most appropriate material kind for <span class="hlt">microwave-water</span> experiments was determined by a new energy loss rate calculation technique. This new energy loss calculation is a determinative factor for material permeability at <span class="hlt">microwave</span> frequency band (1-100 GHz). This experimental series aim to investigate the rationality of using <span class="hlt">microwave</span> in heating industry. Theoretically, heating <span class="hlt">water</span> by <span class="hlt">microwave</span> (with steady frequency 2.45 GHz) is analyzed from sub-molecular to Classical Mechanic results of heating. In the study, we examined Quantum Mechanical base of heating <span class="hlt">water</span> by <span class="hlt">microwave</span> experiments. As a result, we derived a Semi-Quantum Mechanical equation for <span class="hlt">microwave-water</span> interactions and thus, Wien displacement law can be derived to verify experimental observations by this equation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012Icar..218..807G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012Icar..218..807G"><span>Diurnal physical temperature at Sinus Iridum area retrieved from observations of Chinese Chang'E-1 <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gong, Xiaohui; Jin, Ya-Qiu</p> <p>2012-04-01</p> <p>According to the incidence and azimuth angles of the Sun during observations of Chinese Chang'E-1 (CE-1) lunar satellite, brightness temperatures (Tb) at different lunar local time observed by the CE-1 multi-channel <span class="hlt">radiometers</span>, especially at the Sinus Iridum (i.e. Bay of Rainbow) area, are collected from the transformation between the principal and local coordinates at the observed site, which demonstrates the Tb distribution and its diurnal variation. Based on a three-layer radiative transfer model of the lunar media, the CE-1 Tb data at 19.35 and 37.0 GHz channels are applied to invert the physical temperatures of both the dust and the regolith layer at Sinus Iridum area, where might be the CE-3 landing site, at different lunar local times. The physical temperature variations with the lunar local time and other geophysical parameters of lunar layered media are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611522R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611522R"><span>First continuous time series of tropical, mid-latitudinal and polar middle-atmospheric wind profile measurements with a ground-based <span class="hlt">microwave</span> Doppler-spectro-<span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rüfenacht, Rolf; Kämpfer, Niklaus; Murk, Axel; Eriksson, Patrick; Buehler, Stefan A.; Kivi, Rigel; Keckhut, Philippe; Hauchecorne, Alain; Duflot, Valentin</p> <p>2014-05-01</p> <p>Wind is one of the key parameters for the characterisation of the atmosphere and the understanding of its dynamics. Despite this, no continuously operating instrument for wind measurements in the upper stratosphere and lower mesosphere existed so far. Aiming to contribute to the closing of this data gap by exploiting the potential of <span class="hlt">microwave</span> radiometry the Institute of Applied Physics of the University of Bern built a ground-based 142 GHz Doppler-spectro-<span class="hlt">radiometer</span> with the acronym WIRA (WInd <span class="hlt">RAdiometer</span>). WIRA is specifically designed for the measurement of middle-atmospheric horizontal wind and is sensitive to the altitude range between 35 and 70 km. The architecture of the <span class="hlt">radiometer</span> is fairly compact what makes it transportable and suitable for campaign use. WIRA is conceived in a way that it can be operated remotely and does hardly require any maintenance. The operational use of WIRA started in September 2010. Since a technical upgrade in autumn 2012 which drastically increased the signal to noise ratio of the instrument, the meridional component is permanently measured along with the zonal wind to get a full picture of the horizontal wind field. During the last year the wind retrieval algorithm has been entirely rebuilt and tested. It is now based on the optimal estimation technique (OEM) and uses an upgraded version of the ARTS/QPACK radiative transfer and inversion model. Time series of middle-atmospheric wind from measurement campaigns of 7 to 11 months duration at mid and high latitude sites (Bern, 46°57' N, 7°26' E; Sodankylä, 67°22' N, 26°38' E; Observatoire de Haute-Provence, 43°56' N, 5°43' E) have been obtained. In September 2013 WIRA was moved to Observatoire du Maïdo (21°04' S, 55°23' E) to study the dynamics of the tropical middle atmosphere. The measurements have been compared to the data from the ECMWF model. Generally good agreement has been found in the stratosphere, however systematic discrepancies exist in the mesosphere. At the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800018139','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800018139"><span>A 94/183 GHz aircraft <span class="hlt">radiometer</span> system for Project Storm Fury</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gagliano, J. A.; Stratigos, J. A.; Forsythe, R. E.; Schuchardt, J. M.; Welch, J. M.; Gallentine, D. O.</p> <p>1980-01-01</p> <p>A <span class="hlt">radiometer</span> design suitable for use in NASA's WB-57F aircraft to collect data from severe storm regions was developed. The design recommended was a 94/183 GHz scanning <span class="hlt">radiometer</span> with 3 IF channels on either side of the 183.3 GHz <span class="hlt">water</span> vapor line and a single IF channel for a low loss atmospheric window channel at 94 GHz. The development and construction of the 94/183 GHz scanning <span class="hlt">radiometer</span> known as the Advanced <span class="hlt">Microwave</span> Moisture Sounder (AMMS) is presented. The <span class="hlt">radiometer</span> scans the scene below the aircraft over an angle of + or - 45 degrees with the beamwidth of the scene viewed of approximately 2 degrees at 94 GHz and 1 degree at 183 GHz. The AMMS data collection system consists of a microcomputer used to store the <span class="hlt">radiometer</span> data on the flight cartridge recorder, operate the stepper motor driven scanner, and collect housekeeping data such as thermistor temperature readings and aircraft time code.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980git..rept.....G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980git..rept.....G"><span>A 94/183 GHz aircraft <span class="hlt">radiometer</span> system for Project Storm Fury</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gagliano, J. A.; Stratigos, J. A.; Forsythe, R. E.; Schuchardt, J. M.; Welch, J. M.; Gallentine, D. O.</p> <p>1980-04-01</p> <p>A <span class="hlt">radiometer</span> design suitable for use in NASA's WB-57F aircraft to collect data from severe storm regions was developed. The design recommended was a 94/183 GHz scanning <span class="hlt">radiometer</span> with 3 IF channels on either side of the 183.3 GHz <span class="hlt">water</span> vapor line and a single IF channel for a low loss atmospheric window channel at 94 GHz. The development and construction of the 94/183 GHz scanning <span class="hlt">radiometer</span> known as the Advanced <span class="hlt">Microwave</span> Moisture Sounder (AMMS) is presented. The <span class="hlt">radiometer</span> scans the scene below the aircraft over an angle of + or - 45 degrees with the beamwidth of the scene viewed of approximately 2 degrees at 94 GHz and 1 degree at 183 GHz. The AMMS data collection system consists of a microcomputer used to store the <span class="hlt">radiometer</span> data on the flight cartridge recorder, operate the stepper motor driven scanner, and collect housekeeping data such as thermistor temperature readings and aircraft time code.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810010998&hterms=snowpack&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsnowpack','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810010998&hterms=snowpack&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsnowpack"><span>Monitoring snowpack properties by passive <span class="hlt">microwave</span> sensors on board of aircraft and satellites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, A. T. C.; Foster, J. L.; Hall, D. K.; Rango, A.</p> <p>1980-01-01</p> <p>Snowpack properties such as <span class="hlt">water</span> equivalent and snow wetness may be inferred from variations in measured <span class="hlt">microwave</span> brightness temperatures. This is because the emerged <span class="hlt">microwave</span> radiation interacts directly with snow crystals within the snowpack. Using vertically and horizontally polarized brightness temperatures obtained from the multifrequency <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (MFMR) on board a NASA research aircraft and the electrical scanning <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (ESMR) and scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (SMMR) on board the Nimbus 5, 6, and 7 satellites, linear relationships between snow depth or <span class="hlt">water</span> equivalent and <span class="hlt">microwave</span> brightness temperature were developed. The presence of melt <span class="hlt">water</span> in the snowpack generally increases the brightness temperatures, which can be used to predict snowpack priming and timing of runoff.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810010998&hterms=priming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpriming','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810010998&hterms=priming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpriming"><span>Monitoring snowpack properties by passive <span class="hlt">microwave</span> sensors on board of aircraft and satellites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chang, A. T. C.; Foster, J. L.; Hall, D. K.; Rango, A.</p> <p>1980-01-01</p> <p>Snowpack properties such as <span class="hlt">water</span> equivalent and snow wetness may be inferred from variations in measured <span class="hlt">microwave</span> brightness temperatures. This is because the emerged <span class="hlt">microwave</span> radiation interacts directly with snow crystals within the snowpack. Using vertically and horizontally polarized brightness temperatures obtained from the multifrequency <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (MFMR) on board a NASA research aircraft and the electrical scanning <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (ESMR) and scanning multichannel <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (SMMR) on board the Nimbus 5, 6, and 7 satellites, linear relationships between snow depth or <span class="hlt">water</span> equivalent and <span class="hlt">microwave</span> brightness temperature were developed. The presence of melt <span class="hlt">water</span> in the snowpack generally increases the brightness temperatures, which can be used to predict snowpack priming and timing of runoff.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020010583','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020010583"><span>Resolution Enhancement of Spaceborne <span class="hlt">Radiometer</span> Images</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Krim, Hamid</p> <p>2001-01-01</p> <p>Our progress over the last year has been along several dimensions: 1. Exploration and understanding of Earth Observatory System (EOS) mission with available data from NASA. 2. Comprehensive review of state of the art techniques and uncovering of limitations to be investigated (e.g. computational, algorithmic ...). and 3. Preliminary development of resolution enhancement algorithms. With the advent of well-collaborated satellite <span class="hlt">microwave</span> <span class="hlt">radiometers</span>, it is now possible to obtain long time series of geophysical parameters that are important for studying the global hydrologic cycle and earth radiation budget. Over the world's ocean, these <span class="hlt">radiometers</span> simultaneously measure profiles of air temperature and the three phases of atmospheric <span class="hlt">water</span> (vapor, liquid, and ice). In addition, surface parameters such as the near surface wind speed, the sea surface temperature, and the sea ice type and concentration can be retrieved. The special sensor <span class="hlt">microwaves</span> imager SSM/I has wide application in atmospheric remote sensing over the ocean and provide essential inputs to numerical weather-prediction models. SSM/I data has also been used for land and ice studies, including snow cover classification measurements of soil and plant moisture contents, atmospheric moisture over land, land surface temperature and mapping polar ice. The brightness temperature observed by SSM/I is function of the effective brightness temperature of the earth's surface and the emission scattering and attenuation of the atmosphere. Advanced <span class="hlt">Microwave</span> Scanning <span class="hlt">Radiometer</span> (AMSR) is a new instrument that will measure the earth radiation over the spectral range from 7 to 90 GHz. Over the world's ocean, it will be possible to retrieve the four important geographical parameters SST, wind speed, vertically integrated <span class="hlt">water</span> vapor, vertically integrated cloud liquid <span class="hlt">water</span> L.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Icar..294...72H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Icar..294...72H"><span>Comparison and evaluation of the Chang'E <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data based on theoretical computation of brightness temperatures at the Apollo 15 and 17 sites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Guo-Ping; Chan, Kwing L.; Zheng, Yong-Chun; Tsang, Kang T.; Xu, Ao-Ao</p> <p>2017-09-01</p> <p>There are significant differences (in the order of 3 to 20 K) between the lunar brightness temperatures (TBs) as measured by the <span class="hlt">microwave</span> <span class="hlt">radiometers</span> (MRM) onboard Chang'E (CE)-1 and -2. To determine which set is more accurate, we have carried out a dataset comparison using theoretical calculations of the TBs (four frequency channels) versus local time at the Apollo 15 and 17 landing sites, where the thermal parameters are well-constrained by the in-situ measurements. Based on these parameters, we sought to constrain fits between theory and observation, as uncertainties still exist in parameters involved in the <span class="hlt">microwave</span> transfer computation. We found that: (i) CE-1/2 TBs have almost constant biases (negative, different for different channels) from the theoretical TBs. The averaged biases for each channel are smaller for CE-1; (ii) TBs of the high frequency channels (19.35/37 GHz) show a better fit with theory than the low frequency channels. The channel 4 (37 GHz) TBs from CE-1 are consistently shifted by about 1 K from the theoretical values. Adjustments in the order of 20 K are instead needed for the two CE-2 low frequency channels (3/7.8 GHz). Based on this comparison, we conclude that the CE-1 dataset to be more accurate than CE-2 one in terms of temperature accuracy (not spatial resolution). We also offer a possible explanation for the significant TB differences between CE-1 and CE-2, and propose a possible recalibration method as a starting point towards the realignment of the two datasets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Icar..232...34F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Icar..232...34F"><span>High frequency thermal emission from the lunar surface and near surface temperature of the Moon from Chang’E-2 <span class="hlt">microwave</span> <span class="hlt">radiometer</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fang, Tuo; Fa, Wenzhe</p> <p>2014-04-01</p> <p>Near surface temperature of the Moon and thermal behaviors of the lunar regolith can provide important information for constraining thermal and magmatic evolution models of the Moon and engineering constrains for in situ lunar exploration system. In this study, China’s Chang’E-2 (CE-2) <span class="hlt">microwave</span> <span class="hlt">radiometer</span> (MRM) data at high frequency channels are used to investigate near surface temperature of the Moon given the penetration ability of <span class="hlt">microwave</span> into the desiccated and porous lunar regolith. Factors that affect high frequency brightness temperature (TB), such as surface slope, solar albedo and dielectric constant, are analyzed first using a revised Racca’s temperature model. Radiative transfer theory is then used to model thermal emission from a semi-infinite regolith medium, with considering dielectric constant and temperature profiles within the regolith layer. To decouple the effect of diurnal temperature variation in the uppermost lunar surface, diurnal averaged brightness temperatures at high frequency channels are used to invert mean diurnal surface and subsurface temperatures based on their bilinear profiles within the regolith layer. Our results show that, at the scale of the spatial resolution of CE-2 MRM, surface slope of crater wall varies typically from about 20° to 30°, and this causes a variation in TB about 10-15 K. Solar albedo can give rise to a TB difference of about 5-10 K between maria and highlands, whereas a ∼2-8 K difference can be compensated by the dielectric constant on the other hand. Inversion results indicate that latitude (ϕ) variations of the mean diurnal surface and subsurface temperatures follow simple rules as cos0.30ϕ and cos0.36ϕ, respectively. The inverted mean diurnal temperature profiles at the Apollo 15 and 17 landing sites are also compared with the Apollo heat flow experiment data, showing an inversion uncertainty <4 K for surface temperature and <1 K for subsurface temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Icar..275...97W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Icar..275...97W"><span>Inversions of subsurface temperature and thermal diffusivity on the Moon based on high frequency of Chang'E-1 <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wei, Guangfei; Li, Xiongyao; Wang, Shijie</p> <p>2016-09-01</p> <p>Thermal behavior of regolith reflects its thermophysical properties directly on the Moon. In this study, we employed the Fourier temperature model and inverted mean subsurface temperature and thermal diffusivity from high frequency of Chang'E-1 <span class="hlt">microwave</span> <span class="hlt">radiometer</span> data. The result showed that the mafic lunar mare endured higher thermal regime than that of feldspathic highland in a lunar cycle. As expected, the highland diffusivity with mean value 2.5 × 10-4 cm2/s is greater than the mean value 0.3 × 10-4 cm2/s of lunar mare. It indicated that the highland material responded more quickly than that of lunar mare to the changes of surface temperature in a diurnal day. In addition, thermal anomalous regions and hot/cold spots were also identified by diffusivity. For the thermal anomalous regions, Mare Tranquillitatis for example, with more contents of (FeO+TiO2), agglutinate and high maturity index corresponded to greater diffusivity (∼1.0 × 10-4 cm2/s) and is more sensitive to the variations of temperature than the neighboring Mare Serenitatis (∼0.3 × 10-4 cm2/s). Thus, inversion and comparison of regolith thermophysical properties can reveal more information of geological evolution on the Moon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920035396&hterms=radebaugh&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dradebaugh','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920035396&hterms=radebaugh&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dradebaugh"><span>A comparison of sea ice parameters computed from Advanced Very High Resolution <span class="hlt">Radiometer</span> and Landsat satellite imagery and from airborne passive <span class="hlt">microwave</span> radiometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Emery, W. J.; Radebaugh, M.; Fowler, C. W.; Cavalieri, D.; Steffen, K.</p> <p>1991-01-01</p> <p>AVHRR-derived sea ice parameters from the Bering Sea are compared with those computed from nearly coincident (within 6 hr) Landsat MSS imagery and from the Aircraft Multichannel <span class="hlt">Microwave</span> <span class="hlt">Radiometer</span> (AMMR) flown on the NASA DC-8 in order to evaluate the accuracy and reliability of AVHRR-mapped sea-ice concentration and ice edge. Mean ice-concentration differences between AVHRR near-infrared (channel 2) and Landsat MSS data ranged from -0.8 to 1.8 percent with a mean value of 0.5 percent; rms differences ranged from 6.8 to 17.7 percent. Mean differences were larger for AVHRR thermal infrared (channel 4) ice concentrations ranging from -2.2 to 8.4 percent with rms differences from 8.6 to 26.8 percent. Mean differences between AVHRR channel 2 concentrations and the AMMR data ranged from -19.7 to 18.9 percent, while rms values went from 17.0 to 44.8 percent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987PhDT.........4C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987PhDT.........4C"><span>A sky temperature survey at 19.2 GHz using a balloon borne Dicke <span class="hlt">radiometer</span> for anisotropy tests of the cosmic <span class="hlt">microwave</span> background</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cottingham, David A.</p> <p></p> <p>A large area sky survey at a resolution of 3 degrees carried out with a balloon-borne Dicke <span class="hlt">radiometer</span> using a liquid helium cooled ruby maser amplifier is described. The instrument and method of observation are described. The data from one flight of the instrument are analyzed to produce a map of sky temperature covering roughly declination -15 to +75 degrees and right ascension 7 to 23 h at a typical sensitivity of 1.5 mK per 3 degrees resolution element. The calibration of this map in terms of antenna temperature is accurate to 3 percent. Analysis of the sky map indicates that the components of the dipole anisotropy of the cosmic <span class="hlt">microwave</span> background (CMB) are (in thermodynamic temperature) Taux = -3.46 + or - 0.09 mK, Tauy = 0.41 + or - 0.07 mK, Tauz = -0.50 + or - 0.08 mK, implying that the magnitude is Tau = 3.52 + or - 0.08 mK and has its bright pole at alpha = 11 h 33 m + or - 6 m, delta + -8.2 deg + or - 1.5 deg (statistical errors). These data place an upper bound of delta T/T less than .0002 (95 percent confidence level) on anisotropy of the CMB other than the dipole at all angular scales greater than 3 degrees.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890018809','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890018809"><span><span class="hlt">Microwave</span> remote sensing of soil moisture</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shiue, J. C.; Wang, J. R.</p> <p>1988-01-01</p> <p>Knowledge of soil moisture is important to many disciplines, such as agriculture, hydrology, and meteorology. Soil moisture distribution of vast regions can be measured efficiently only with remote sensing techniques from airborne or satellite platforms. At low <span class="hlt">microwave</span> frequencies, <span class="hlt">water</span> has a much larger dielectric constant than dry soil. This difference manifests itself in surface emissivity (or reflectivity) change between dry and wet soils, and can be measured by a <span class="hlt">microwave</span> <span class="hlt">radiometer</span> or radar. The <span class="hlt">Microwave</span> Sensors and Data Communications Branch is developing <span class="hlt">microwave</span> remote sensing techniques using both radar and radiometry, but primarily with <span class="hlt">microwave</span> radiometry. The efforts in these areas range from developing algorithms for data interpretation to conducting feasibility studies for space systems, with a primary goal of developing a <span class="hlt">microwave</span> <span class="hlt">radiometer</span> for soil moisture measurement from satellites, such as EOS or the Space Station. These efforts are listed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/138020','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/138020"><span><span class="hlt">Microwave</span> measurements of the <span class="hlt">water</span> content of bentonite</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Latorre, V.R.; Glenn, H.D.</p> <p>1991-01-01</p> <p>The theory of operation of <span class="hlt">microwave</span> coaxial resonators is described. Sample preparation and the application of resonator techniques to the measurement of the permittivity (dielectric constant) of bentonite is discussed. The results indicate a fairly linear change in resonant frequency for saturation levels at 10, 30, 50, 70, and 90%. The results clearly demonstrate that this <span class="hlt">microwave</span> technique is a viable method for measuring <span class="hlt">water</span> content of soils. A discussion of additional applications of <span class="hlt">microwave</span> methods for determining <span class="hlt">water</span> content in materials is presented. 3 refs., 5 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070018802','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070018802"><span><span class="hlt">Microwave</span> Extraction of <span class="hlt">Water</span> from Lunar Regolith Simulant</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ethridge, Edwin C.; Kaukler, William</p> <p>2007-01-01</p> <p>Nearly a decade ago the DOD Clementine lunar orbital mission obtained data indicating that the permanently shaded regions at the lunar poles may have permanently frozen <span class="hlt">water</span> in the lunar soil. Currently NASA's Robotic Lunar Exploration Program, RLEP-2, is planned to land at the lunar pole to determine if <span class="hlt">water</span> is present. The detection and extraction of <span class="hlt">water</span> from the permanently frozen permafrost is an important goal for NASA. Extraction of <span class="hlt">water</span> from lunar permafrost has a high priority in the In-Situ Resource Utilization, ISRU, community for human life support and as a fuel. The use of <span class="hlt">microwave</span> processing would permit the extraction of <span class="hlt">water</span> without the need to dig, drill, or excavate the lunar surface. <span class="hlt">Microwave</span> heating of regolith is potentially faster and more efficient than any other heating methods due to the very low thermal conductivity of the lunar regolith. Also, <span class="hlt">microwaves</span> can penetrate into the soil permitting <span class="hlt">water</span> removal from deep below the lunar surface. A cryogenic vacuum test facility was developed for evaluating the use of <span class="hlt">microwave</span> heating and <span class="hlt">water</span> extraction from a lunar regolith permafrost simulant. <span class="hlt">Water</span> is obtained in a cryogenic cold trap even with soil conditions below 0 C. The results of <span class="hlt">microwave</span> extraction of <span class="hlt">water</span> experiments will be presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20090042919&hterms=consumer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dconsumer','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20090042919&hterms=consumer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dconsumer"><span>Using <span class="hlt">Microwaves</span> for Extracting <span class="hlt">Water</span> from the Moon</span></a></p> <p><a target="_blank" href=