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Geoscience and Remote Sensing, IEEE Transactions on

Issue 4 • Date Jul 1998

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Displaying Results 1 - 25 of 26
  • Prelaunch algorithm and data format for the Level 1 calibration products for the EOS-AM1 Moderate Resolution Imaging Spectroradiometer (MODIS)

    Page(s): 1142 - 1151
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    The Moderate Resolution Imaging Spectroradiometer (MODIS) radiometric calibration product (Level 1B) is described for the thermal emissive and reflective solar bands. A band-integrated radiance is produced for all measurements. A reflectance factor product is also produced for the reflected solar band measurements. Specific sensor design characteristics are identified to assist in understanding how the calibration algorithm software product is designed. The product file format is summarized, and the location for the current file format is provided View full abstract»

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  • Improvements in coverage frequency of ocean color: combining data from SeaWiFS and MODIS

    Page(s): 1350 - 1353
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB)  

    Large improvements in coverage frequency (daily to four-day) can be expected by combining ocean color data from the Sea-Viewing Wide Field Of-View Sensor (SeaWiFS) and Moderate Resolution Imaging Spectrometer (MODIS) missions. Results indicated 40-47% increases in global coverage over SeaWiFS alone in one day and >100% in low latitudes. The missions are highly complementary for observation of short-term processes View full abstract»

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  • Calibration strategy for the Earth Observing System (EOS)-AM1 platform

    Page(s): 1056 - 1061
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (96 KB)  

    The Earth Observing System (EOS) is an international, 18-year program in global remote sensing of the Earth comprising multiple instruments flown on several satellite platforms. The first EOS platform, AM1, scheduled for launch in 1998, includes five instruments designed to make radiometric and reflectance measurements of the Earth over a wavelength range extending from the visible to the thermal infrared. The goal of the EOS-AM1 platform and instruments is to advance the scientific understanding of the Earth in the areas of clouds, aerosols, radiative balance, terrestrial and oceanic characterization, and the carbon cycle. In order to achieve this goal, the EOS-AM1 instruments must produce state-of-the-art accurate, precise, and consistent radiance and reflectance measurements over their five-year lifetimes. In addition, the production of continuous remote-sensing data from multiple instruments on several platforms requires that the remote-sensing measurements of the AM1 platform be radiometrically tied to the measurements made by instruments on successive platforms. This is achieved through careful prelaunch and postlaunch instrument calibration, cross-calibration, and level 1B data validation (i.e. vicarious calibration). This paper presents an overview of the calibration, cross-calibration, and level 1B data validation strategy for the AM1 platform View full abstract»

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  • Earth Observing System AM1 mission to Earth

    Page(s): 1045 - 1055
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB)  

    In 1998, NASA launches EOS-AMI, the first of a series of the Earth Observing System (EOS) satellites. EOS will monitor the evolution of the state of the earth for 18 years, starting with the morning observations of EOS-AM1 (10:30 a.m. equatorial crossing time). An integrated view of the earth, as planned by EOS, is needed to study the interchange of energy, moisture, and carbon between the lands, oceans, and atmosphere. The launch of EOS-AM1 and other international satellites marks a new phase of climate and global change research. Both natural and anthropogenic climate change have been studied for more than a century. It is now recognized that processes that vary rapidly in time and space-e.g. aerosol, clouds, land use, and exchanges of energy and moisture-must be considered to adequately explain the temperature record and predict future climate change. Frequent measurements with adequate resolution, as only possible from spacecraft, are key tools in such an effort. The versatile and highly accurate EOS-AM1 data, together with previous satellite records, as well as data from ADEOS, TRMM, SeaWiFS, ATSR, MERIS, ENVISAT, EOS-PM1, Landsat and ground-based networks is expected to revolutionize the way scientists look at climate change. This article introduces the EOS-AM1 mission and the special issue devoted to it. Following a brief historical perspective for an insight into the purpose and objectives of the mission, the authors summarize the characteristics of the five instruments onboard EOS-AM1. Specifically, they concentrate on the innovative elements of these five instruments and provide examples of the science issues that require this type of data View full abstract»

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  • Clouds and the Earth's Radiant Energy System (CERES): algorithm overview

    Page(s): 1127 - 1141
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    The Clouds and the Earth's Radiant Energy System (CERES) is part of NASA's Earth Observing System (EOS), CERES objectives include the following. (1) For climate change analysis, provide a continuation of the Earth Radiation Budget Experiment (ERBE) record of radiative fluxes at the top-of-the-atmosphere (TOA), analyzed using the same techniques as the existing ERBE data. (2) Double the accuracy of estimates of radiative fluxes at TOA and the Earth's surface. (3) Provide the first long-term global estimates of the radiative fluxes within the Earth's atmosphere. (4) Provide cloud property estimates collocated in space and time that are consistent with the radiative fluxes from surface to TOA. In order to accomplish these goals, CERES uses data from a combination of spaceborne instruments: CERES scanners, which are an improved version of the ERBE broadband radiometers, and collocated cloud spectral imager data on the same spacecraft. The CERES cloud and radiative flux data products should prove extremely useful in advancing the understanding of cloud-radiation interactions, particularly cloud feedback effects on the Earth's radiation balance. For this reason, the CERES data should be fundamental to the ability to understand, detect, and predict global climate change. CERES results should also be very useful for studying regional climate changes associated with deforestation, desertification, anthropogenic aerosols, and ENSO events. This overview summarizes the Release 3 version of the planned CERES data products and data analysis algorithms. These algorithms are a prototype for the system that will produce the scientific data required for studying the role of clouds and radiation in the Earth's climate system View full abstract»

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  • Prelaunch calibrations of the Clouds and the Earth's Radiant Energy System (CERES) Tropical Rainfall Measuring Mission and Earth Observing System morning (EOS-AM1) spacecraft thermistor bolometer sensors

    Page(s): 1173 - 1185
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    The Clouds and the Earth's Radiant Energy System (CERES) spacecraft scanning thermistor bolometer sensors measure Earth radiances in the broadband shortwave solar (0.3-5.0 μm) and total (0.3->100 μm) spectral bands as well as in the 8-12-μm water vapor window spectral band. On November 27, 1997, the launch of the Tropical Rainfall Measuring Mission (TRMM) spacecraft placed the first set of CERES sensors into orbit, and 30 days later, the sensors initiated operational measurements of the Earth radiance fields. In 1998, the Earth Observing System morning (EOS-AM1) spacecraft will place the second and third sensor sets into orbit. The prelaunch CERES sensors' count conversion coefficients (gains and zero-radiance offsets) were determined in vacuum ground facilities. The gains were tied radiometrically to the International Temperature Scale of 1990 (ITS-90). The gain determinations included the spectral properties (reflectance, transmittance, emittance, etc.) of both the sources and sensors as well as the in-field-of-view (FOV) and out-of-FOV sensor responses. The resulting prelaunch coefficients for the TRMM and EOS-AM1 sensors are presented. Inflight calibration systems and on-orbit calibration approaches are described, which are being used to determine the temporal stabilities of the sensors' gains and offsets from prelaunch calibrations through on-orbit measurements. Analyses of the TRMM prelaunch and on-orbit calibration results indicate that the sensors have retained their ties to ITS-90 at accuracy levels better than ±0.3% between the 1995 prelaunch and 1997 on-orbit calibrations View full abstract»

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  • MISR prelaunch instrument calibration and characterization results

    Page(s): 1186 - 1198
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB)  

    Each of the nine cameras that compose the Multi-angle Imaging SpectroRadiometer (MISR) has been rigorously tested, characterized, and calibrated. Requirements on these tests include a 3% (1σ) radiometric calibration requirement, spectral response function determination of both the in- and out-of-band regions, and distortion mapping. The latter test determines the relative look-angle to the ground corresponding to each focal plane detector element. This is established to within one-tenth of the instantaneous field-of-view. Most of the performance testing was done on the cameras as they completed assembly. This was done to take advantage of the serial delivery of the hardware, minimize the required size of the thermal-vacuum facilities, and allow testing to occur early in the schedule allocated for the hardware build. This proved to be an effective strategy, as each of the test objectives was met. Additional testing as an integrated instrument included verification of the data packetization, camera pointing, and clearances of the fields-of-view. Results of these studies have shown that the MISR cameras are of high quality and will meet the needs of the MISR science community. Highly accurate calibration data are on-hand and available for conversion of camera output to radiances View full abstract»

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  • ASTER Level-1 data processing algorithm

    Page(s): 1101 - 1112
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is an advanced multispectral imager with high spatial, spectral, and radiometric performance built for the EOS-AM1 polar orbiting spacecraft. ASTER covers a wide spectral region from visible to thermal infrared with 14 spectral bands. To meet this wide spectral coverage, ASTER has three optical-sensing subsystems: visible and near-infrared (VNIR), shortwave infrared (SWIR), and thermal infrared (TIR). In addition, the VNIR subsystem has two telescopes (nadir and backward telescopes) for stereo data acquisition. This ASTER instrument configuration with multitelescopes requires highly refined ground processing for the generation of Level-1 data products that are radiometrically calibrated and geometrically corrected. The algorithm developed for the ASTER Level-1 data processing is described View full abstract»

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  • ASTER as a source for topographic data in the late 1990s

    Page(s): 1282 - 1289
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    Topography is a fundamental Earth characteristic that can be measured for studies of the land surface. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) onboard the EOS-AM1 platform will acquire along-track stereo data for topographic mapping. ASTER is capable of recording 771 digital stereo pairs per day, each covering 60×60 km on the ground, at 15-m resolution, with a base-to-height ratio of 0.6. According to present plans, approximately 30 digital elevation models (DEMs), accurate to within ±7 to ±50 m (RMSEz) will be produced daily by processing facilities in Japan and the United States. The Land Processes Distributed Active Archive Center (LP-DAAC) at the United States Geological Survey's (USGS's) EROS Data Center (EDC) will emphasize the use of automated stereocorrelation procedures to produce absolute DEMs tied to ground control. During the six-year mission, ASTER has the potential to provide a coherent, digital stereo data set covering all of the Earth's land surface. At minimum, ASTER DEMs will augment topographic data from other sources. Results of simulations of ASTER stereo data using existing satellite and aircraft data over validation sites in Huntsville, AL, and Iguala, Mexico, illustrate the value of high-resolution ASTER DEMs and how actual ASTER DEMs will be validated View full abstract»

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  • Prelaunch characteristics of the Moderate Resolution Imaging Spectroradiometer (MODIS) on EOS-AM1

    Page(s): 1088 - 1100
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (340 KB)  

    The Moderate Resolution Imaging Spectroradiometer (MODIS), with 36 bands and 0.25-, 0.5-, and 1.0-km geometric instantaneous-fields-of-view (GIFOVs) at nadir, has completed system level testing and has been integrated onto the Earth Observing System (EOS)-AM1 spacecraft, which is slated for launch in 1998. Raytheon Santa Barbara Remote Sensing (SBRS), Goleta, CA, the MODIS developer, has performed extensive characterization and calibration measurements that have demonstrated a system that meets or exceeds most of NASA's demanding requirements. Based on this demonstrated capability, the MODIS Science Team, an international group of 28 land, ocean, atmosphere, and calibration remote-sensing scientists, has commenced delivery of algorithms that will routinely calculate 42 MODIS standard data products postlaunch. These products range from atmospheric aerosols, snow cover, and land and water surface temperature to leaf area index, ocean chlorophyll concentration, and sea ice extent, to name just a few. A description of the Science Team, including members' research interests and descriptions of their MODIS algorithms, can be found at the MODIS homepage (http://ltpwww.gsfc.nasa.gov/MODIS/MODIS.html). The MODIS system level testing included sufficient measurements in both ambient and thermal-vacuum environments to both demonstrate specification compliance and enable postlaunch implementation of radiometric calibration algorithms. The latter will include calculations to account for changes in response versus scan angle, response versus temperature, and response linearity. The system level tests also included performance verification of the onboard calibration systems, including the solar diffuser stability monitor (SDSM), the blackbody (BB), and the spectral radiometric calibration assembly (SRCA), which will enahle monitoring of MODIS performance postlaunch. Descriptions of these subsystems are also on the MODIS homepage View full abstract»

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  • Overview of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)

    Page(s): 1062 - 1071
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a research facility instrument provided by the Ministry of International Trade and Industry (MITI), Tokyo, Japan to be launched on NASA's Earth Observing System morning (EOS-AM1) platform in 1998. ASTER has three spectral hands in the visible near-infrared (VNIR), six bands in the shortwave infrared (SWIR), and five bands in the thermal infrared (TIR) regions, with 15-, 30-, and 90-m ground resolution, respectively. The VNIR subsystem has one backward-viewing band for stereoscopic observation in the along-track direction. Because the data will have wide spectral coverage and relatively high spatial resolution, it will be possible to discriminate a variety of surface materials and reduce problems in some lower resolution data resulting from mixed pixels. ASTER will, for the first time, provide high-spatial resolution multispectral thermal infrared data from orbit and the highest spatial resolution surface spectral reflectance temperature and emissivity data of all of the EOS-AM1 instruments. The primary science objective of the ASTER mission is to improve understanding of the local- and regional-scale processes occurring on or near the Earth's surface and lower atmosphere, including surface-atmosphere interactions. Specific areas of the science investigation include the following: (1) land surface climatology; (2) vegetation and ecosystem dynamics; (3) volcano monitoring; (4) hazard monitoring; (5) aerosols and clouds; (6) carbon cycling in the marine ecosystem; (7) hydrology; (8) geology and soil; and (9) land surface and land cover change. There are three categories of ASTER data: a global map, regional monitoring data sets, and local data sets to be obtained for requests from individual investigators View full abstract»

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  • Multi-angle Imaging SpectroRadiometer (MISR) instrument description and experiment overview

    Page(s): 1072 - 1087
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB)  

    The Multi-angle Imaging SpectroRadiometer (MISR) instrument is scheduled for launch aboard the first of the Earth Observing System (EOS) spacecraft, EOS-AM1. MISR will provide global, radiometrically calibrated, georectified, and spatially coregistered imagery at nine discrete viewing angles and four visible/near-infrared spectral bands. Algorithms specifically developed to capitalize on this measurement strategy will be used to retrieve geophysical products for studies of clouds, aerosols, and surface radiation. This paper provides an overview of the as-built instrument characteristics and the application of MISR to remote sensing of the Earth View full abstract»

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  • A temperature and emissivity separation algorithm for Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images

    Page(s): 1113 - 1126
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB)  

    The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) scanner on NASA's Earth Observing System (EOS)-AM1 satellite (launch scheduled for 1998) will collect five bands of thermal infrared (TIR) data with a noise equivalent temperature difference (NEΔT) of ⩽0.3 K to estimate surface temperatures and emissivity spectra, especially over land, where emissivities are not known in advance. Temperature/emissivity separation (TES) is difficult because there are five measurements but six unknowns. Various approaches have been used to constrain the extra degree of freedom. ASTER's TES algorithm hybridizes three established algorithms, first estimating the normalized emissivities and then calculating emissivity band ratios. An empirical relationship predicts the minimum emissivity from the spectral contrast of the ratioed values, permitting recovery of the emissivity spectrum. TES uses an iterative approach to remove reflected sky irradiance. Based on numerical simulation, TES should be able to recover temperatures within about ±1.5 K and emissivities within about ±0.015. Validation using airborne simulator images taken over playas and ponds in central Nevada demonstrates that, with proper atmospheric compensation, it is possible to meet the theoretical expectations. The main sources of uncertainty in the output temperature and emissivity images are the empirical relationship between emissivity values and spectral contrast, compensation for reflected sky irradiance, and ASTER's precision, calibration, and atmospheric compensation View full abstract»

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  • Techniques for the retrieval of aerosol properties over land and ocean using multiangle imaging

    Page(s): 1212 - 1227
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (484 KB)  

    Aerosols are believed to play a direct role in the radiation budget of Earth, but their net radiative effect is not well established, particularly on regional scales. Whether aerosols heat or cool a given location depends on their composition and column amount and on the surface albedo, information that is not routinely available, especially over land. Obtaining global information on aerosol and surface radiative characteristics, over both ocean and land, is a task of the Multi-angle Imaging SpectroRadiometer (MISR), an instrument to be launched in 1998 on the Earth Observing System EOS-AM1 platform. Three algorithms are described that will be implemented to retrieve aerosol properties globally using MISR data. Because of the large volume of data to be processed on a daily basis, these algorithms rely on lookup tables of atmospheric radiative parameters and predetermined aerosol mixture models to expedite the radiative transfer (RT) calculations. Over oceans, the “dark water” algorithm is used, taking full advantage of the nature of the MISR data. Over land, a choice of algorithms is made, depending on the surface types within a scene-dark water bodies, heavily vegetated areas, or high-contrast terrain. The retrieval algorithms are tested on simulated MISR data, computed using realistic aerosol and surface reflectance models. The results indicate that aerosol optical depth can be retrieved with an accuracy of 0.05 or 10%, whichever is greater, and some information can be obtained about the aerosol chemical and physical properties View full abstract»

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  • Determination of land and ocean reflective, radiative, and biophysical properties using multiangle imaging

    Page(s): 1266 - 1281
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    Knowledge of the directional and hemispherical reflectance properties of natural surfaces, such as soils and vegetation canopies, is essential for classification studies and canopy model inversion. The Multi-angle Imaging SpectroRadiometer (MISR), an instrument to be launched in 1998 onboard the EOS-AM1 platform, will make global observations of the Earth's surface at 1.1-km spatial resolution, with the objective of determining the atmospherically corrected reflectance properties of most of the land surface and the tropical ocean. The algorithms to retrieve surface directional reflectances, albedos, and selected biophysical parameters using MISR data are described. Since part of the MISR data analyses includes an aerosol retrieval, it is assumed that the optical properties of the atmosphere (i.e. aerosol characteristics) have been determined well enough to accurately model the radiative transfer process. The core surface retrieval algorithms are tested on simulated MISR data, computed using realistic surface reflectance and aerosol models, and the sensitivity of the retrieved directional and hemispherical reflectances to aerosol type and column amount is illustrated. Included is a summary list of the MISR surface products View full abstract»

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  • An overview of MODIS capabilities for ocean science observations

    Page(s): 1250 - 1265
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    The Moderate Resolution Imaging Spectroradiometer (MODIS) will add a significant new capability for investigating the 70% of the Earth's surface that is covered by oceans, in addition to contributing to the continuation of a decadal scale time series necessary for climate change assessment in the oceans. Sensor capabilities of particular importance for improving the accuracy of ocean products include high SNR and high stability for narrow or spectral bands, improved onboard radiometric calibration and stability monitoring, and improved science data product algorithms. Spectral bands for resolving solar-stimulated chlorophyll fluorescence and a split window in the 4-μm region for SST will result in important new global ocean science products for biology and physics. MODIS will return full global data at 1-km resolution. The complete suite of Levels 2 and 3 ocean products is reviewed, and many areas where MODIS data are expected to make significant, new contributions to the enhanced understanding of the oceans' role in understanding climate change are discussed. In providing a highly complementary and consistent set of observations of terrestrial, atmospheric, and ocean observations, MODIS data will provide important new information on the interactions between Earth's major components View full abstract»

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  • The Airborne Multi-angle Imaging SpectroRadiometer (AirMISR): instrument description and first results

    Page(s): 1339 - 1349
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    An Airborne Multi-angle Imaging SpectroRadiometer (AirMISR) instrument has been developed to assist in validation of the Earth Observing System (EOS) MISR experiment. Unlike the EOS MISR, which contains nine individual cameras pointed at discrete look angles, AirMISR utilizes a single camera in a pivoting gimbal mount. The AirMISR camera has been fabricated from MISR brassboard and engineering model components and, thus, has similar radiometric and spectral response as the MISR cameras. This paper provides a description of the AirMISR instrument and summarizes the results of engineering flights conducted during 1997 View full abstract»

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  • Atmospheric correction of ASTER

    Page(s): 1199 - 1211
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    An atmospheric correction algorithm for operational use for the high-spatial resolution, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is presented. The correction is a straightforward approach relying on inputs from other satellite sensors to determine the atmospheric characteristics of the scene to be corrected. Methods for the solar reflective and thermal infrared (TIR) are presented separately. The solar-reflective approach uses a lookup table (LUT) based on output from a Gauss-Seidel iteration radiative transfer code. A method to handle adjacency effects is included that relies on model output, assuming a checkerboard surface. An example of a numerical simulation shows that the effect of a land surface on the radiance over the ocean is stronger just off the coastal zone and decreases exponentially with increasing distance from the land. A typical numerical simulation is performed over the Tsukuba lake area in Japan. The TIR approach relies on the radiative transfer code Moderate Resolution Atmospheric Radiance and Transmittance Model (MODTRAN). The code is run for a given set of atmospheric conditions for multiple locations in the scene for several representative elevations. Pixel-by-pixel radiances are then found using spatial interpolation. Sensitivity analysis of the methods indicate that the results of the atmospheric correction will be limited by the accuracies of the input parameters View full abstract»

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  • Eos AM-1 Platform, Instruments, And Scientific Data

    Page(s): 0_2 - 0_3
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    First Page of the Article
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  • The ASTER polar cloud mask

    Page(s): 1302 - 1312
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    This research is concerned with the problem of producing polar cloud masks for satellite imagery. The results presented are for Thematic Mapper (TM) data from the northern and southern polar regions, however, the techniques discussed will be applied to ASTER data when it becomes available. A series of classification techniques have been implemented and tested, the most promising of which is a neural network classifier. To use a neural network classifier, the pixels in the data must be transformed into feature vectors, some of which are used for training the network and the remainder of which are reserved for testing the final system. The first challenge is the identification of pure pixel samples from the imagery. The Interactive Visual Image Classification System (IVICS) was developed specifically for this project to make this task simpler for the human expert. After labeling the pixels, the feature vectors are generated. One hundred and forty potential vector elements, consisting of linear and nonlinear combinations of the satellite channel data, have been identified. Because smaller input vectors reduce the difficulty of training and can improve classification accuracy, the set of potential vector elements must be reduced. Two techniques have been tested: a histogram-based selection method and a fuzzy logic method. Both have proven effective for this task. Although the polar region is the only area considered in this work, a system that can produce cloud masks for all areas of the globe will be required. Thus, speed, extensibility, and flexibility requirements must be added to the accuracy constraint. To achieve these goals, a two-stage classification approach is used. The first stage uses a series of static and adaptive thresholds derived from statistical analysis of the polar scenes to reduce the set of possible classes to which a pixel may be assigned, once a cluster of classes has been selected, a neural network trained to distinguish between the classes in the cluster is used to make the ultimate classification View full abstract»

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  • ASTER preflight and inflight calibration and the validation of Level 2 products

    Page(s): 1161 - 1172
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    Describes the preflight and inflight calibration approaches used for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The system is a multispectral, high-spatial resolution sensor on the Earth Observing System's EOS-AM1 platform. Preflight calibration of ASTER uses well-characterized sources to provide calibration and preflight round-robin exercises to understand biases between the calibration sources of ASTER and other EOS sensors. These round-robins rely on well-characterized, ultra-stable radiometers. An experiment field in Yokohama, Japan, showed that the output from the source used for the visible and near-infrared (VNIR) subsystem of ASTER may be underestimated by 1.5%, but this is still within the 4% specification for the absolute, radiometric calibration of these bands. Inflight calibration will rely on vicarious techniques and onboard blackbodies and lamps. Vicarious techniques include ground-reference methods using desert and water sites. A recent joint field campaign gives confidence that these methods currently provide absolute calibration to better than 5%, and indications are that uncertainties less than the required 4% should be achievable at launch. The EOS-AM1 platform will also provide a spacecraft maneuver that will allow ASTER to see the Moon, allowing further characterization of the sensor. A method for combining the results of these independent calibration results is presented. The paper also describes the plans for validating the Level 2 data products from ASTER. These plans rely heavily upon field campaigns using methods similar to those used for the ground-reference, vicarious calibration methods View full abstract»

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  • Design and preflight performance of ASTER instrument protoflight model

    Page(s): 1152 - 1160
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    The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is an advanced multispectral imager with high spatial, spectral, and radiometric resolution, built to fly on the EOS-AM1 spacecraft along with four other instruments, which will be launched in 1998. The ASTER instrument covers a wide spectral region, from visible to thermal infrared with 14 spectral bands. To meet the wide spectral coverage, optical sensing units of ASTER are separated into three subsystems: visible and near-infrared (VNIR) subsystem, shortwave infrared (SWIR) subsystem, and thermal infrared (TIR) subsystem. ASTER also has an along-track stereoscopic viewing capability using one of the near-infrared bands. To acquire the stereo data, the VNIR subsystem has two telescopes, one for nadir and another for backward viewing. Several new technologies are adopted as design challenges to realize high performance. Excellent observational performances are obtained by a pushbroom VNIR radiometer with a high spatial resolution of 15 m, a pushbroom SWIR radiometer with high spectral resolution, and a whiskbroom-type TIR radiometer with high spatial, spectral, and radiometric resolutions. The preflight performance is evaluated through a protoflight model (PFM) View full abstract»

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  • MODIS land data storage, gridding, and compositing methodology: Level 2 grid

    Page(s): 1324 - 1338
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    The methodology used to store a number of the Moderate Resolution Imaging Spectroradiometer (MODIS) land products is described. The approach has several scientific and data processing advantages over conventional approaches used to store remotely sensed data sets and may be applied to any remote-sensing data set in which the observations are geolocated to subpixel accuracy. The methodology will enable new algorithms to be more accurately developed because important information about the intersection between the sensor observations and the output grid cells are preserved. The methodology will satisfy the very different needs of the MODIS land product generation algorithms, allow sophisticated users to develop their own application-specific MODIS land data sets, and enable efficient processing and reprocessing of MODIS land products. A generic MODIS land gridding and compositing algorithm that takes advantage of the data storage structure and enables the exploitation of multiple observations of the surface more fully than conventional approaches is described. The algorithms are illustrated with simulated MODIS data, and the practical considerations of increased data storage are discussed View full abstract»

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  • MISR photogrammetric data reduction for geophysical retrievals

    Page(s): 1290 - 1301
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    The theoretical concept, based on modern photogrammetric methods, underlying the design of the Multi-angle Imaging SpectroRadiometer (MISR) science data processing system, responsible for the autonomous and continuous georectification of multiangle imagery, is the subject of this paper. The algorithm partitions effort between the MISR Science Computing Facility and the Earth Observing System (EOS) Distributed Active Archive Center (DAAC) in a way that minimizes the amount of processing required at the latter location to rectify and map project remotely sensed data online, as it comes from the instrument. The algorithm deals with the following issues: (1) removal of the errors introduced by inaccurate navigation and attitude data; (2) removal of the distortions introduced by surface topography; (3) attainment of a balance between limited hardware resources, huge data volume and processing requirements, and autonomous and nonstop aspects of the production system View full abstract»

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  • Key characteristics of MODIS data products

    Page(s): 1313 - 1323
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    Forty science products totaling 600 GB of storage volume per day will be produced from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS). Eighty-five percent of this data volume is in products that are in the instrument's scan geometry (processing Levels 1 and 2) that are not Earth located. Before ordering MODIS data products, users should consider processing level, data formats, product size, and the unique characteristics of MODIS products. Given the data volumes associated with the MODIS Levels 1 and 2 products, the resources required to process them and the issues associated with the scanning geometry of the instrument, users are encouraged to order data products that are Earth located. These include Level 3 products, which are produced on fixed global grids and Level 2G products, in which observations and their Earth location have been stored in bins of the MODIS global grids View full abstract»

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Aims & Scope

 

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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Meet Our Editors

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