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Retrieval of soil moisture from passive and active L/S band sensor (PALS) observations during the soil moisture experiment in 2002 (SMEX) / U. Narayan in Remote sensing of environment, vol 92 n° 4 (30 September 2004)
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Titre : Retrieval of soil moisture from passive and active L/S band sensor (PALS) observations during the soil moisture experiment in 2002 (SMEX) Type de document : Article/Communication Auteurs : U. Narayan, Auteur ; V. Lakshmi, Auteur ; E. Njoku, Auteur Année de publication : 2004 Article en page(s) : pp 483 - 496 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] bande L
[Termes IGN] bande S
[Termes IGN] bande spectrale
[Termes IGN] capteur actif
[Termes IGN] capteur passif
[Termes IGN] Glycine max
[Termes IGN] humidité du sol
[Termes IGN] Iowa (Etats-Unis)
[Termes IGN] maïs (céréale)
[Termes IGN] Passive and Active L and S band Sensor
[Termes IGN] régression
[Termes IGN] Soil Moisture Experiment
[Termes IGN] teneur en eau de la végétation
[Termes IGN] transfert radiatifRésumé : (Auteur) The Soil Moisture Experiments in 2002 (SMEX02) were conducted in Iowa between June 25th and July 12th, 2002. A major aim of the experiments was examination of existing algorithms for soil moisture retrieval from active and passive microwave remote sensors under high vegetation water content conditions. The data obtained from the passive and active L and S band sensor (PALS) along with physical variables measured by in situ sampling have been used in this study to demonstrate the sensitivity of the instrument to soil moisture and perform soil moisture retrieval using statistical regression and physical modeling techniques. The land cover conditions in the region studied were predominantly soybean and corn crops with average vegetation water contents ranging from 0 to ~ 5 kg/m2. The PALS microwave sensitivity to soil moisture under these vegetation conditions was investigated for both passive and active measurements. The performance of the PALS instrument and retrieval algorithms has been analyzed, indicating soil moisture retrieval errors of approximately 0.04 g/g gravimetric soil moisture. Statistical regression techniques have been shown to perform satisfactorily with soil moisture retrieval error of around 0.05 g/g gravimetric soil moisture. The retrieval errors were higher for the corn than for the soybean fields due to the higher vegetation water content of the corn crops. However, the algorithms performed satisfactorily over the full range of vegetation conditions. Numéro de notice : A2004-414 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.05.018 En ligne : https://doi.org/10.1016/j.rse.2004.05.018 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26941
in Remote sensing of environment > vol 92 n° 4 (30 September 2004) . - pp 483 - 496[article]SMEX02: field scale variability, time stability and similarity of soil moisture / J.M. Jacobs in Remote sensing of environment, vol 92 n° 4 (30 September 2004)
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Titre : SMEX02: field scale variability, time stability and similarity of soil moisture Type de document : Article/Communication Auteurs : J.M. Jacobs, Auteur ; B.P. Mohanty, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 436 - 446 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse diachronique
[Termes IGN] Argile
[Termes IGN] bassin hydrographique
[Termes IGN] flore locale
[Termes IGN] humidité du sol
[Termes IGN] Iowa (Etats-Unis)
[Termes IGN] pente
[Termes IGN] point de vérification
[Termes IGN] précision
[Termes IGN] Soil Moisture Experiment
[Termes IGN] stabilité dans le tempsRésumé : (Auteur) Evaluation of air- or space-bome remote sensors measuring soil moisture requires strategic ground-based sampling. As part of the Soil Moisture Experiment 2002 (SMEX02), daily surface soil moisture sampling at 90-140 locations were conducted in four fields in Walnut Creek watershed, Iowa. Various combinations of soils, vegetation, and topography characterize the fields. Depending on the field's characteristics and soil moisture content, 3 - 32 independent measurements were necessary to capture the field mean volumetric soil moisture with a + 2% bias and 95% confidence interval. Validation of the retrieved soil moisture products from the aircraft microwave instruments using the average of 14 samples per field is more appropriate for dry (25% volumetric soil moisture) range than for intermediate soil moisture range. Time stability analysis showed that an appropriately selected single sampling point could provide similar accuracy across a range of soil moisture conditions. Analyses based on landscape position (depression, hilltop, steep slope, and mild slope) showed that locations with mild slopes consistently exhibit time stable features. Hilltop and steep slope locations consistently underestimated mean field soil moisture. Soils parameters could not be used to identify time stable features as sampling locations with relatively high sand content consistently underestimated the field mean while those locations with relatively high clay content consistently overestimated the field mean. However, the slope position characterization of time stable features was enhanced using soils properties. The mild slope locations having the best time-stable features are those with moderate to moderately high clay content as compare to the field average (28-30% clay). Numéro de notice : A2004-413 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.02.017 En ligne : https://doi.org/10.1016/j.rse.2004.02.017 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26940
in Remote sensing of environment > vol 92 n° 4 (30 September 2004) . - pp 436 - 446[article]Watershed scale temporal and spatial stability of soil moisture and its role in validating satellite estimates / M.H. Cosh in Remote sensing of environment, vol 92 n° 4 (30 September 2004)
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Titre : Watershed scale temporal and spatial stability of soil moisture and its role in validating satellite estimates Type de document : Article/Communication Auteurs : M.H. Cosh, Auteur ; Thomas J. Jackson, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 427 - 435 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Advanced Microwave Scanning Radiometer
[Termes IGN] analyse comparative
[Termes IGN] bassin hydrographique
[Termes IGN] étalonnage des données
[Termes IGN] humidité du sol
[Termes IGN] Iowa (Etats-Unis)
[Termes IGN] ligne de partage des eaux
[Termes IGN] limite de résolution géométrique
[Termes IGN] Soil Moisture ExperimentRésumé : (Auteur) Watershed scale soil moisture estimates are necessary to validate current remote sensing products, such as those from the Advanced Microwave Scanning Radiometer (AMSR). Unfortunately, remote sensing technology does not currently resolve the land surface at a scale that is easily observed with ground measurements. One approach to validation is to use existing soil moisture measurement networks and scale these point observations up to the resolution of remote sensing footprints. As part of the Soil Moisture Experiment 2002 (SMEX02), one such soil moisture gaging system in the Walnut Creek Watershed, Iowa, provided robust estimates of the soil moisture average for a watershed throughout the summer of 2002. Twelve in situ soil moisture probes were installed across the watershed. These probes recorded soil moisture at a depth of 5 cm from June 29, 2002 to August 19, 2002. The sampling sites were analyzed for temporal and spatial stability by several measures including mean relative difference, Spearman rank, and correlation coefficient analysis. Representative point measurements were used to estimate the watershed scale (3 25 km) soil moisture average and shown to be accurate indicators with low variance and bias of the watershed scale soil moisture distribution. This work establishes the validity of this approach to provide watershed scale soil moisture estimates in this study region for the purposes of satellite validation with estimation errors as small as 3%. Also, the potential sources of error in this type of analysis are explored. This study is a first step in the implementation of large-scale soil moisture validation using existing networks such as the Soil Climate Analysis Network (SCAN) and several Agricultural Research Service watersheds as a basis for calibrating satellite soil moisture products, for networks design, and designing field experiments. Numéro de notice : A2004-412 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.02.016 En ligne : https://doi.org/10.1016/j.rse.2004.02.016 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26939
in Remote sensing of environment > vol 92 n° 4 (30 September 2004) . - pp 427 - 435[article]Assessment of the new national geoid height model, GEOID03 / D.R. Roman in Surveying and land information science, vol 64 n° 3 (01/09/2004)
[article]
Titre : Assessment of the new national geoid height model, GEOID03 Type de document : Article/Communication Auteurs : D.R. Roman, Auteur ; Y.M. Wang, Auteur ; J. Hamilton, Auteur Année de publication : 2004 Article en page(s) : pp 153 - 162 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] analyse comparative
[Termes IGN] conversion altimétrique
[Termes IGN] Etats-Unis
[Termes IGN] géoïde altimétrique
[Termes IGN] géoïde gravimétrique
[Termes IGN] géoïde local
[Termes IGN] point d'appui
[Termes IGN] point de vérificationRésumé : (Auteur) The GEOID03 model was developed in the same manner as GEOID99 using an underlying gravimetric geoid, USGG2003, and updated GPS ellipsoidal heights on leveled benchmarks (GPSBMs). USGG2003 is similar to G99SSS, however, it includes an updated model for gravity anomalies in the deep ocean areas, GSF00.1. The convention surface for GEOID03 was developed from 14,185 GPSBMs at a 5 arc-minute grid interval, which provided a substantial increase in the spatial coverage and reduced errors due to the interpolation. The fit to these same points afterwards was 4.8 (2s), which was comprised of both correlated (attribuate to GEOID03) and uncorrelated (GPS observation error) signals. The uncorrelated signal was 4.2 cm (2s) and correlated signal was 2.0 cm (2s), with a 3.5km correlation wavelength. GEOID03 thus had a very good fit with the GPSBMs, and can be relied upon to convert between the NAD 83 and Navd88 datums to the centimeter level. Numéro de notice : A2004-601 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27117
in Surveying and land information science > vol 64 n° 3 (01/09/2004) . - pp 153 - 162[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 121-04031 SL Revue Centre de documentation Revues en salle Disponible Evaluating airborne hyperspectral imagery for rangeland assessment in south Texas / James H. Everitt in Geocarto international, vol 19 n° 3 (September - November 2004)
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Titre : Evaluating airborne hyperspectral imagery for rangeland assessment in south Texas Type de document : Article/Communication Auteurs : James H. Everitt, Auteur ; C. Yang, Auteur ; M.R. Davis, Auteur Année de publication : 2004 Article en page(s) : pp 23 - 31 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] bande visible
[Termes IGN] composition colorée
[Termes IGN] ERDAS Imagine
[Termes IGN] flore locale
[Termes IGN] image hyperspectrale
[Termes IGN] occupation du sol
[Termes IGN] rayonnement proche infrarouge
[Termes IGN] réflectance spectrale
[Termes IGN] Texas (Etats-Unis)Résumé : (Auteur) Airborne hyperspectral imagery was evaluated for differentiating among rangeland ecological variables on two range sites (tight sandy loam and shallow ridge) on south Texas rangelands. Field spectroradiometric reflectance measurements made on dominant vegetation (plant species and vegetation mixtures) and soil land-use types on the two sites identified six wavelengths [five visible and one near-infrared (NIR)] where significant spectral differences occurred among the parameters. The spectral bands that corresponded to these wavelengths were extracted from the 128-band hyperspectral images obtained of each site and used to develop false color composites that were subjected to computer classifications and accuracy assessments. The bands selected for the composites included the green (498.9 nm), yellow-green (549.7 nm), orange (629.6 nm), red (651.3 nm), dark red (680.4 nm), and NIR (825.5 tim). Accuracy assessments performed on the classification maps of four false color composites of the tight sandy loam site had overall accuracies ranging from 76% to 85%; the highest accuracy was obtained from the composite made up of the NIR, red, and yellow-green bands. Accuracy assessments performed on the classification maps of three composites of the shallow ridge site had overall accuracies ranging from 74% to 77%; the highest accuracy was acquired from a composite comprised of the NIR, orange, and yellow-green bands. Overall accuracies were considered good and indicate that several band combinations can be used successfully to differentiate among, rangeland parameters in southern Texas. Key Words: remote sensing, hyperspectral imagery, reflectance, false color composite imagery, accuracy assessment. Numéro de notice : A2004-478 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106040408542314 Date de publication en ligne : 02/01/2008 En ligne : https://doi.org/10.1080/10106040408542314 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26996
in Geocarto international > vol 19 n° 3 (September - November 2004) . - pp 23 - 31[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 059-04031 RAB Revue Centre de documentation En réserve L003 Disponible A spatial access-oriented implementation of a 3-D GIS topological data model for urban entities / J. Lee in Geoinformatica, vol 8 n° 3 (septembre - novembre 2004)
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