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Geoscience and Remote Sensing, IEEE Transactions on

Issue 3 • Date March 2006

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Displaying Results 1 - 25 of 34
  • [Front cover]

    Page(s): c1
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  • IEEE Transactions on Geoscience and Remote Sensing publication information

    Page(s): c2
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  • Table of contents

    Page(s): 465 - 466
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  • List of reviewers

    Page(s): 469
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  • Calibration of WindSat polarimetric channels with a vicarious cold reference

    Page(s): 470 - 475
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    Absolute calibration of WindSat's third and fourth Stokes brightness temperatures (T3 and T4) is needed at the tenth of Kelvin level in order to adequately resolve their dependence on wind direction. Previous aircraft based fully polarimetric microwave radiometers have generally relied on "circle flights", during which a single area of the ocean is observed at all azimuth angles, to estimate residual biases in the calibration of its polarimetric channels. WindSat, the first spaceborne fully polarimetric microwave radiometer, operates in low Earth orbit and thus cannot execute this traditional calibration technique. A new method is presented to estimate the residual biases that are present in WindSat's T3 and T4 estimates. The method uses a vicarious cold reference brightness temperature applied to measurements made by WindSat at ±45° slant linear (TP and TM) and left- and right-hand circular (TL and TR) polarization. WindSat derives the third and fourth Stokes brightness temperatures by the differences TP-TM and TL-TR, respectively. The method is demonstrated by applying it to the 10.7-GHz WindSat observations. Calibration biases of 0.2-0.6 K are determined with a precision of 0.04 K. View full abstract»

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  • Deep-space calibration of the WindSat radiometer

    Page(s): 476 - 495
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4864 KB) |  | HTML iconHTML  

    The WindSat microwave polarimetric radiometer consists of 22 channels of polarized brightness temperatures operating at five frequencies: 6.8, 10.7, 18.7, 23.8, and 37.0 GHz. The 10.7-, 18.7-, and 37.0-GHz channels are fully polarimetric (vertical/horizontal, ±45° and left-hand and right-hand circularly polarized) to measure the four Stokes radiometric parameters. The principal objective of this Naval Research Laboratory experiment, which flys on the USAF Coriolis satellite, is to provide the proof of concept of the first passive measurement of ocean surface wind vector from space. This paper presents details of the on-orbit absolute radiometric calibration procedure, which was performed during of a series of satellite pitch maneuvers. During these special tests, the satellite pitch was slowly ramped to +45° (and -45°), which caused the WindSat conical spinning antenna to view deep space during the forward (or aft portion) of the azimuth scan. When viewing the homogeneous and isotropic brightness of space (2.73 K) through both the main reflector and the cold-load calibration reflector, it is possible to determine the absolute calibration of the individual channels and the relative calibration bias between polarimetric channels. Results demonstrate consistent and stable channel calibrations (with very small brightness biases) that exceed the mission radiometric calibration requirements. View full abstract»

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  • Geolocation and pointing accuracy analysis for the WindSat sensor

    Page(s): 496 - 505
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    Geolocation and pointing accuracy analyses of the WindSat flight data are presented. The two topics were intertwined in the flight data analysis and will be addressed together. WindSat has no unusual geolocation requirements relative to other sensors, but its beam pointing knowledge accuracy is especially critical to support accurate polarimetric radiometry. Pointing accuracy was improved and verified using geolocation analysis in conjunction with scan bias analysis. Two methods were needed to properly identify and differentiate between data time tagging and pointing knowledge errors. Matchups comparing coastlines indicated in imagery data with their known geographic locations were used to identify geolocation errors. These coastline matchups showed possible pointing errors with ambiguities as to the true source of the errors. Scan bias analysis of U, the third Stokes parameter, and of vertical and horizontal polarizations provided measurement of pointing offsets resolving ambiguities in the coastline matchup analysis. Several geolocation and pointing bias sources were incrementally eliminated resulting in pointing knowledge and geolocation accuracy that met all design requirements. View full abstract»

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  • Polarization rotation and the third Stokes parameter: the effects of spacecraft attitude and Faraday rotation

    Page(s): 506 - 515
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB) |  | HTML iconHTML  

    The third Stokes parameter of ocean surface brightness temperatures measured by the WindSat instrument is sensitive to the rotation angle between the polarization vectors at the ocean surface and the instrument. This rotation angle depends on the spacecraft attitude (roll, pitch, yaw) as well as the Faraday rotation of the electromagnetic radiation passing through the Earth's ionosphere. Analyzing the WindSat antenna temperatures, we find biases in the third Stokes parameter as function of the along-scan position of up to 1.5 K in all feedhorns. This points to a misspecification of the reported spacecraft attitude. A single attitude correction of -0.16° roll and 0.18° pitch for the whole instrument eliminates all the biases. We also study the effect of Faraday rotation at 10.7 GHz on the accuracy of the third Stokes parameter and the sea surface wind direction retrieval and demonstrate how this error can be corrected using values from the International Reference Ionosphere for the total electron content when computing Faraday rotation. View full abstract»

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  • WindSat on-orbit warm load calibration

    Page(s): 516 - 529
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (776 KB) |  | HTML iconHTML  

    Postlaunch calibration of the WindSat polarimetric microwave radiometer indicates the presence of thermal gradients across the calibration warm load during some portions of the year. These gradients are caused by reflected solar illumination or eclipse and increase total calibration errors. This paper describes the WindSat warm load and presents the measured on-orbit data which clearly illustrate the anomalous responses seen in the warm load calibration data. Detailed thermal modeling predictions of the WindSat on-orbit performance are presented along with the satellite orbital geometry model with solar inputs in order to explain the physical causes of the thermal gradients. To reduce the resultant calibration errors during periods of anomalous warm load behavior, a correction algorithm was developed which uses the physical temperatures of the gain stages in the receiver electronics to calculate an effective gain. This calibration algorithm is described, and its performance and expected accuracy are examined. View full abstract»

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  • WindSat radio-frequency interference signature and its identification over land and ocean

    Page(s): 530 - 539
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB) |  | HTML iconHTML  

    Radio-frequency interference (RFI) in the spaceborne multichannel radiometer data of WindSat and the Advanced Microwave Scanning Radiometer-EOS is currently being detected using a spectral difference technique. Such a technique does not explicitly utilize multichannel correlations of radiometer data, which are key information in separating RFI from natural radiations. Furthermore, it is not optimal for radiometer data observed over ocean regions due to the inherent large natural variability of spectral difference over ocean. In this paper, we first analyzed multivariate WindSat and Scanning Multichannel Microwave Radiometer (SMMR) data in terms of channel correlation, information content, and principal components of WindSat and SMMR data. Then two methods based on channel correlation were developed for RFI detection over land and ocean. Over land, we extended the spectral difference technique using principal component analysis (PCA) of RFI indices, which integrates statistics of target emission/scattering characteristics (through RFI indices) and multivariate correlation of radiometer data into a single statistical framework of PCA. Over ocean, channel regression of X-band can account for nearly all of the natural variations in the WindSat data. Therefore, we use a channel regression-based model difference technique to directly predict RFI-free brightness temperature, and therefore RFI intensity. Although model difference technique is most desirable, it is more difficult to apply over land due to heterogeneity of land surfaces. Both methods improve our knowledge of RFI signatures in terms of channel correlations and explore potential RFI mitigation, and thus provide risk reductions for future satellite passive microwave missions such as the NPOESS Conical Scanning Microwave Imager/Sounder. The new RFI algorithms are effective in detecting RFI in the C- and X-band Windsat radiometer channels over land and ocean. View full abstract»

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  • A polarimetric survey of radio-frequency interference in C- and X-bands in the continental united states using WindSat radiometry

    Page(s): 540 - 548
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB) |  | HTML iconHTML  

    Transmissions from ground-based systems in C- and X-bands present a significant challenge to the use of these bands for passive microwave remote sensing from aircraft and satellites. Because future missions plan to continue to use these frequencies, it is important to characterize and understand the nature of interference in as much of the candidate spectrum as possible. This paper presents a statistical analysis of interference observed in the continental U.S. using six months of data collected from the C- and X-band channels of the WindSat microwave radiometer. Our findings are consistent with those of previous studies by Li et al. and Njoku et al., which are based on data obtained from the Advanced Microwave Scanning Radiometer-EOS using somewhat similar center frequencies and bandwidths. Results show significant radio-frequency interference (RFI) at C-band, including brightnesses in horizontal and vertical polarizations in excess of 330 K, while X-band RFI is less obvious through direct examination of measured linearly polarized brightnesses. Evidence of lower levels of RFI is provided through use of the spectral and polarization indexes of Li et al., which reveal likely RFI contributions at X-band as well. Further confirmation of X-band RFI is obtained through analysis of the polarimetric channels, which are shown to provide direct evidence of RFI in contrast to the linearly polarized channels. A temporal analysis of the largest C-band RFI sources is also provided in an attempt to further understand their properties. View full abstract»

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  • Comparison of WindSat brightness temperatures with two-scale model predictions

    Page(s): 549 - 559
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    Predictions of the polarized microwave brightness temperatures over the ocean are made using a two-scale surface bidirectional reflectance model combined with an atmospheric radiative transfer model. The reflected atmospheric radiation is found to contribute significantly to the magnitude and directional dependence of the brightness temperatures. The predicted brightness temperatures are also sensitive to the form of the shortwave spectrum. Calculations are made using a new physically based model for the wave spectrum, and preliminary comparisons are made with WindSat observations at 10.7, 18.7, and 37 GHz, for wind speeds ranging from 0-20 m/s and for vertically integrated atmospheric water vapor concentrations from 0-70 mm. Predictions of the mean (azimuthally averaged) brightness temperatures for vertical and horizontal polarization agree quite well with WindSat observations over this range of wind speeds and water vapor concentrations. The predicted azimuthal variations of the third and fourth Stokes parameters also agree fairly well with the observations, except for the fourth Stokes parameter at 37 GHz. Further adjustments of the wave spectrum are expected to improve the agreement. View full abstract»

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  • An efficient two-scale model for the computation of thermal emission and atmospheric reflection from the sea surface

    Page(s): 560 - 568
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    An efficient implementation of the two-scale model of sea surface thermal emission and atmospheric reflection is described. The model is applied in a study of the reflection of downwelling atmospheric radiation. Results show that reflected downwelling radiation can increase azimuthal variations of total observed brightnesses. View full abstract»

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  • Effects of foam on ocean surface microwave emission inferred from radiometric observations of reproducible breaking waves

    Page(s): 569 - 583
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3144 KB) |  | HTML iconHTML  

    WindSat, the first satellite polarimetric microwave radiometer, and the NPOESS Conical Microwave Imager/Sounder both have as a key objective the retrieval of the ocean surface wind vector from radiometric brightness temperatures. Available observations and models to date show that the wind direction signal is only 1-3 K peak-to-peak at 19 and 37 GHz, much smaller than the wind speed signal. In order to obtain sufficient accuracy for reliable wind direction retrieval, uncertainties in geophysical modeling of the sea surface emission on the order of 0.2 K need to be removed. The surface roughness spectrum has been addressed by many studies, but the azimuthal signature of the microwave emission from breaking waves and foam has not been adequately addressed. Recently, a number of experiments have been conducted to quantify the increase in sea surface microwave emission due to foam. Measurements from the Floating Instrumentation Platform indicated that the increase in ocean surface emission due to breaking waves may depend on the incidence and azimuth angles of observation. The need to quantify this dependence motivated systematic measurement of the microwave emission from reproducible breaking waves as a function of incidence and azimuth angles. A number of empirical parameterizations of whitecap coverage with wind speed were used to estimate the increase in brightness temperatures measured by a satellite microwave radiometer due to wave breaking in the field of view. These results provide the first empirically based parameterization with wind speed of the effect of breaking waves and foam on satellite brightness temperatures at 10.8, 19, and 37 GHz. View full abstract»

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  • Polarimetric microwave wind radiometer model function and retrieval testing for WindSat

    Page(s): 584 - 596
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    A geophysical model function (GMF), relating the directional response of polarimetric brightness temperatures to ocean surface winds, is developed for the WindSat multifrequency polarimetric microwave radiometer. This GMF is derived from the WindSat data and tuned with the aircraft radiometer measurements for very high winds from the Hurricane Ocean Wind Experiment in 1997. The directional signals in the aircraft polarimetric radiometer data are corroborated by coincident Ku-band scatterometer measurements for wind speeds in the range of 20-35 m/s. We applied an iterative retrieval algorithm using the polarimetric brightness temperatures from 18-, 23-, and 37-GHz channels. We find that the root-mean-square direction difference between the Global Data Assimilation System winds and the closest WindSat wind ambiguity is less than 20° for above 7-m/s wind speed. The retrieval analysis supports the consistency of the Windrad05 GMF with the WindSat data. View full abstract»

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  • A nonlinear optimization algorithm for WindSat wind vector retrievals

    Page(s): 597 - 610
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (848 KB) |  | HTML iconHTML  

    WindSat is a space-based polarimetric microwave radiometer designed to demonstrate the capability to measure the ocean surface wind vector using a radiometer. We describe a nonlinear iterative algorithm for simultaneous retrieval of sea surface temperature, columnar water vapor, columnar cloud liquid water, and the ocean surface wind vector from WindSat measurements. The algorithm uses a physically based forward model function for the WindSat brightness temperatures. Empirical corrections to the physically based model are discussed. We present evaluations of initial retrieval performance using a six-month dataset of WindSat measurements and collocated data from other satellites and a numerical weather model. We focus primarily on the application to wind vector retrievals. View full abstract»

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  • An emissivity-based wind vector retrieval algorithm for the WindSat polarimetric radiometer

    Page(s): 611 - 621
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1048 KB) |  | HTML iconHTML  

    The Naval Research Laboratory WindSat polarimetric radiometer was launched on January 6, 2003 and is the first fully polarimetric radiometer to be flown in space. WindSat has three fully polarimetric channels at 10.7, 18.7, and 37.0 GHz and vertically and horizontally polarized channels at 6.8 and 23.8 GHz. A first-generation wind vector retrieval algorithm for the WindSat polarimetric radiometer is developed in this study. An atmospheric clearing algorithm is used to estimate the surface emissivity from the measured WindSat brightness temperature at each channel. A specular correction factor is introduced in the radiative transfer equation to account for excess reflected atmospheric brightness, compared to the specular assumption, as a function wind speed. An empirical geophysical model function relating the surface emissivity to the wind vector is derived using coincident QuikSCAT scatterometer wind vector measurements. The confidence in the derived harmonics for the polarimetric channels is high and should be considered suitable to validate analytical surface scattering models for polarized ocean surface emission. The performance of the retrieval algorithm is assessed with comparisons to Global Data Assimilation System (GDAS) wind vector outputs. The root mean square (RMS) uncertainty of the closest wind direction ambiguity is less than 20° for wind speeds greater than 6 m/s and less than 15° at 10 m/s and greater. The retrieval skill, the percentage of retrievals in which the first-rank solution is the closest to the GDAS reference, is 75% at 7 m/s and 85% or higher above 10 m/s. The wind speed is retrieved with an RMS uncertainty of 1.5 m/s. View full abstract»

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  • The accuracy of preliminary WindSat vector wind measurements: comparisons with NDBC buoys and QuikSCAT

    Page(s): 622 - 637
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB) |  | HTML iconHTML  

    Two preliminary, six-month long global WindSat vector wind datasets are validated using buoys and QuikSCAT measurements. Buoy comparisons yield speed and direction root mean square accuracies of 1.4 m/s and 25° for the "NESDIS0" product and 1.3 m/s and 23° for the more recently produced "B1" product from the Naval Research Laboratory. WindSat along- and across-wind random component errors of 0.7-1.0 and 2.6-2.8 m/s (respectively) are larger than those calculated for QuikSCAT in the same period. Global WindSat-QuikSCAT comparisons generally confirmed the buoy analyses. While simple rain flags based directly on WindSat brightness temperature measurements alone are shown to overflag for rain systematically, the advanced "Environmental Data Record" rain flag in the B1 product matches well with Special Sensor Microwave/Imager rain detection frequency and preserves the accuracy of the unflagged vector wind measurements. View full abstract»

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  • Evaluation of WindSat wind vector performance with respect to QuikSCAT estimates

    Page(s): 638 - 644
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB) |  | HTML iconHTML  

    The WindSat instrument was launched on January 6, 2003 as part of a risk reduction effort to assess the potential of using spaceborne fully polarimetric radiometry to measure the marine wind vector. Microwave radiometry on the Special Sensor Microwave/Imager onboard the Defense Meteorological Satellite Program satellites has long provided wind speed measurements. Fully polarimetric radiometry offers the additional possibility of obtaining wind direction as well. By contrast, the QuikSCAT satellite uses active microwave measurements to estimate the wind vector from space. It represents the most comprehensive satellite dataset against which to compare WindSat measurements. In this paper, we systematically compare temporally and spatially coincident WindSat and QuikSCAT wind vector measurements against the design goals of the WindSat instrument, taking into consideration expected differences related to instrument precision and the spatial and temporal variability of the wind field. View full abstract»

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  • Observations of tropical cyclone structure from WindSat

    Page(s): 645 - 655
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1432 KB) |  | HTML iconHTML  

    Passive microwave (PMW) radiometric observations of clouds from multichannel imaging sensors onboard low Earth-orbiting environmental satellites are now a vital operational dataset. The first operational passive microwave sensor was the Special Sensor Microwave/Imager onboard the Defense Meteorological Satellite Program satellites, which has been gathering hydrological data records since 1987, and continued with the Tropical Rainfall Measuring Mission (TRMM) and the Advanced Microwave Scanning Radiometer onboard Aqua. These sensors view the underlying scene with an Earth incidence angle near 53° and with a variable azimuthal angle, depending upon the orbit direction and scan position. The WindSat sensor onboard the Coriolis satellite, launched in January 2003, is a five-channel polarimetric PMW radiometer designed to optimize ocean surface wind vector retrievals. While it does not have 85-GHz channels, an added feature is its unique fore-aft viewing capability across a portion of its fore scan swath. This provides a view of the underlying scene from two separate azimuthal directions, which provides added information on the three-dimensional (3-D) structure of clouds and their evolution. In this paper, we compare WindSat and TRMM Precipiation Radar observations of tropical cyclones (TCs) with Monte Carlo radiative transfer simulations performed on idealized 3-D convective cloud structures. The TC 3-D structure and possible tilt in the convective cloud structure are inferred from the difference between the 37-GHz equivalent blackbody brightness temperatures (TB) from the corresponding fore and aft view observations. The information gained from this analysis is important since asymmetries in the cloud vertical and horizontal structure may be an indication of upper level wind shear, which plays a major role in influencing changes of the TC intensity. View full abstract»

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  • Evaluation of hurricane ocean vector winds from WindSat

    Page(s): 656 - 667
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    The ability to accurately measure ocean surface wind vectors from space in all weather conditions is important in many scientific and operational usages. One highly desirable application of satellite-based wind vector retrievals is to provide realistic estimates of tropical cyclone intensity for hurricane monitoring. Historically, the extreme environmental conditions in tropical cyclones (TCs) have been a challenge to traditional space-based wind vector sensing provided by microwave scatterometers. With the advent of passive microwave polarimetry, an alternate tool for estimating surface wind conditions in the TC has become available. This paper evaluates the WindSat polarimetric radiometer's ability to accurately sense winds within TCs. Three anecdotal cases studies are presented from the 2003 Atlantic Hurricane season. Independent surface wind estimates from aircraft flights and other platforms are used to provide surface wind fields for comparison to WindSat retrievals. Results of a subjective comparison of wind flow patterns are presented as well as quantitative statistics for point location comparisons of wind speed and direction. View full abstract»

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  • An evaluation of the potential of polarimetric radiometry for numerical weather prediction using QuikSCAT

    Page(s): 668 - 675
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (528 KB) |  | HTML iconHTML  

    It has been proposed that wind vector information derived from passive microwave radiometry may provide an impact on numerical weather forecasts of similar magnitude to that achieved by scatterometers. Polarimetric radiometers have a lower sensitivity to wind direction than scatterometers at low wind speed but comparable sensitivity at high windspeed. In this paper, we describe an experiment which aimed to determine if an observing system only capable of providing wind direction information at wind speeds over 8 ms-1 can provide comparable impact to one providing wind vectors at wind speeds over 2 ms-1. The QuikSCAT dataset used in the experiments has a wide swath and is used operationally by several forecast centers. The results confirm that assimilation of wind vectors from QuikSCAT only for wind speeds above 8 ms-1 gives similar analysis increments and forecast impacts to assimilating wind vectors at all wind speeds above 2 ms-1. Measurements from the WindSat five frequency polarimetric radiometer are compared with calculations from Met Office global forecast fields, and this also confirms that WindSat measurement and radiative transfer model accuracy appears to be sufficiently good to provide useful information for numerical weather prediction. View full abstract»

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  • Stratospheric ozone isotope enrichment studied by submillimeter wave heterodyne radiometry: the observation capabilities of SMILES

    Page(s): 676 - 693
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    The isotopic ratio of molecules often provides valuable information about past or presently occurring processes in the atmosphere because chemical and physical processes may give rise to isotope fractionation of molecular species. However, there are so far no published satellite measurements on the spatial and temporal variations of ozone isotopes in the stratosphere. Spectroscopic remote sensing methods can theoretically be used to observe ozone isotope fractionation on a global scale, but sufficient accuracy has not yet been achieved. A new generation of submillimeter-wave receivers employing sensitive superconductor-insulator-superconductor (SIS) detector technology will provide new opportunities for precise remote sensing measurements of ozone isotopes on a global scale. We have estimated the observation capabilities of two different SIS instruments, namely the space-station-borne Japanese Experimental Module/Sub-Millimeter-wave Limb Emission Sounder (JEM/SMILES) instrument, currently planned for launch in 2008, as well as the airborne Submillimeter wave Atmospheric Sounder/Airborne Submillimeter SIS Radiometer (SUMAS/ASUR) sensor. Measurements of the airborne sensor, conducted in 1996, are presented in order to demonstrate the detection of normal-O3 and asymmetric-18-O3 in the SMILES frequency bands. In the ideal case, JEM/SMILES has the capability to measure the ozone isotope enrichment (δMO3) in the middle stratosphere with a precision of ∼120/00, ∼110/00, and ∼90/00, for asymmetric-18-O3, symmetric-17-O3, asymmetric-17-O3, respectively, for a daily zonal mean product with resolution of 10° in latitude. The systematic error, including contributions of all instrumental and spectroscopic uncertainties, is estimated to be of the order of 1000/00 to 2000/00 and should be reduced by prelaunch laboratory measurements and in-flight calibrations. A remaining bias in the SMILES measurements will have to be quantified by dedicated validation campaigns. JEM/SMILES should then be capable to provide valuable information on the global distribution and seasonal variation of ozone isotope fractionation in the stratosphere. Thi- s new technology will allow us to shed new light on this still open issue in atmospheric sciences. View full abstract»

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  • RFI detection and mitigation for microwave radiometry with an agile digital detector

    Page(s): 694 - 706
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1128 KB) |  | HTML iconHTML  

    A new type of microwave radiometer detector has been developed that is capable of identifying high and low levels of radio-frequency interference (RFI) and of reducing or eliminating its effect on the measured brightness temperatures. High-level, localized RFI can be easily identified by its unnatural appearance in brightness temperature imagery. Low-level or persistent RFI can be much more difficult to identify and filter out. The agile digital detector (ADD) can discriminate between RFI and natural thermal emission signals by directly measuring higher order moments of the signal than the variance that is traditionally measured. After detection, the ADD then uses spectral filtering methods to selectively remove the RFI. ADD performance is experimentally verified in controlled laboratory tests and in the field near a commercial air traffic control radar. High-level RFI is easily identified and removed. Very low level RFI contamination, with power levels as low as the radiometric measurement uncertainty of the radiometer, is also shown to be reliably detected and removed. View full abstract»

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING (TGRS) is a monthly publication that focuses on the theory, concepts, and techniques of science and engineering as applied to sensing the land, oceans, atmosphere, and space; and the processing, interpretation, and dissemination of this information.

 

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Editor-in-Chief
Antonio J. Plaza
University of Extremadura