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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)
[article]
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)
[article]
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]Analytical solar radiation pressure modelling for GLONASS using a pixel array / Marek Ziebart in Journal of geodesy, vol 75 n° 11 (November 2001)
[article]
Titre : Analytical solar radiation pressure modelling for GLONASS using a pixel array Type de document : Article/Communication Auteurs : Marek Ziebart, Auteur ; Peter Dare, Auteur Année de publication : 2001 Article en page(s) : pp 587 - 599 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Technologies spatiales
[Termes IGN] Global Orbitography Navigation Satellite System
[Termes IGN] international GLONASS experiment
[Termes IGN] modélisation
[Termes IGN] orbitographie
[Termes IGN] rayonnement solaireRésumé : (Auteur) A new method for calculating analytical solar radiation pressure models for GNSS spacecraft has been developed. The method simulates the flux of light from the Sun using a pixel array. The method can cope with a high level of complexity in the spacecraft structure and models effects due to reflected light. Models have been calculated and tested for the Russhar global navigation satellite system GLONASS IIv spacecraft. Results are presented using numerical integration of the force model and longarc satellite laser ranging (SLR) analysis. The integrated trajectory differs from a precise orbit calculated using a network of global tracking stations by circa 2 m root mean square over a 160 000km arc. The observed computed residuals for the 400day SLR arc are circa 28 min. Numéro de notice : A2001-136 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s001900000136 En ligne : https://doi.org/10.1007/s001900000136 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21831
in Journal of geodesy > vol 75 n° 11 (November 2001) . - pp 587 - 599[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-01101 RAB Revue Centre de documentation En réserve L003 Disponible 266-01102 RAB Revue Centre de documentation En réserve L003 Disponible ITRS, PZ-90 and WGS 84: current realizations and the related transformation parameters / Zuheir Altamimi in Journal of geodesy, vol 75 n° 11 (November 2001)
[article]
Titre : ITRS, PZ-90 and WGS 84: current realizations and the related transformation parameters Type de document : Article/Communication Auteurs : Zuheir Altamimi , Auteur ; Claude Boucher , Auteur Année de publication : 2001 Article en page(s) : pp 613 - 619 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] international GLONASS experiment
[Termes IGN] International Terrestrial Reference System
[Termes IGN] système de référence géodésique
[Termes IGN] transformation de coordonnées
[Termes IGN] World Geodetic System 1984Résumé : (Auteur) The first results of the International GLONASS Experiment 1998 (IGEX-98) campaign have provided significant material to illustrate the mutual benefits of the GLONASS system and the realization of the International Terrestrial Reference System (ITRS). A specific aspect, namely the relationship between the World Geodetic System 1984 (WGS 84) and the PZ-90 system using ITRS as a primary standard is investigated. A review of current works is carried out. A transformation strategy is proposed for the three systems based on recent results from IGEX-98 and a independent set of transformation parameters derive by the Jet Propulsion Laboratory from ITRF97 and PZ-90 coordinates for 16 global stations. Numéro de notice : A2001-128 Affiliation des auteurs : IGN+Ext (2012-2019) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s001900100208 En ligne : https://doi.org/10.1007/s001900100208 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26405
in Journal of geodesy > vol 75 n° 11 (November 2001) . - pp 613 - 619[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-01101 RAB Revue Centre de documentation En réserve L003 Disponible 266-01102 RAB Revue Centre de documentation En réserve L003 Disponible Laser-based validation of GLONASS orbits by short-arc technique / François Barlier in Journal of geodesy, vol 75 n° 11 (November 2001)
[article]
Titre : Laser-based validation of GLONASS orbits by short-arc technique Type de document : Article/Communication Auteurs : François Barlier, Auteur ; C. Berger, Auteur ; Pascal Bonnefond, Auteur ; Olivier Laurain, Auteur ; J.F. Mangin, Auteur ; J.M. Torre, Auteur Année de publication : 2001 Article en page(s) : pp 600 - 612 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales
[Termes IGN] Global Orbitography Navigation Satellite System
[Termes IGN] international GLONASS experiment
[Termes IGN] orbitographie
[Termes IGN] poursuite de satelliteRésumé : (Auteur) The International GLONASS Experiment (1GEX98) was carried out between 19 October 1998 and 19 April 1999. Among several objectives was the precise orbit determination of GPS and GLONASS satellites and its validation by laser ranging observations. Local laser-based orbit corrections (radial, tangential and normal components in a rotating orbital local reference frame) are computed using a geometrical short-are technique. The order of magnitude of these corrections is at the level of few decimeters, depending on the considered components. The orbit corrections are analyzed as a function of several parameters (date, orbital plane, geographical area). The mean corrections are at the level of several centimeters. However, when averaging over the entire campaign and for all the satellites, no mean radial, tangential and normal orbit corrections are found. The origin of the observed corrections is considered (errors due to the geocentric gravitational constant, the nongravitational forces, the thermal equilibrium of on-board equipment, the reference systems, the location and the signature of the retroreflector array, and the precision of the satellite laser ranges). Some features are also due to errors in the radiotracking GLONASS orbits. Further investigations will be needed to better understand the origin of various biases. Numéro de notice : A2001-137 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s001900100179 En ligne : https://doi.org/10.1007/s001900100179 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21832
in Journal of geodesy > vol 75 n° 11 (November 2001) . - pp 600 - 612[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 266-01101 RAB Revue Centre de documentation En réserve L003 Disponible 266-01102 RAB Revue Centre de documentation En réserve L003 Disponible The international GLONASS experiment: products, progress and prospects / Robert Weber in Journal of geodesy, vol 75 n° 11 (November 2001)Permalinkvol 75 n° 11 - November 2001 - Special issue on GLONASS (Bulletin de Journal of geodesy) / International association of geodesyPermalinkIntérêts scientifiques de la campagne GLONASS IGEX-98 / Muhammad Ali Sammuneh (2001)PermalinkPermalinkGPS, GLONASS and GALILEO : GNSS research at Delft University of Technology / Frank Kleijer in Geoinformatics, vol 3 n° 2 (01/03/2000)PermalinkLa campagne internationale GLONASS : IGEX-98 / Pascal Willis in Navigation aérienne, maritime, spatiale, terrestre, vol 48 n° 189 (01/01/2000)PermalinkDeutsche Beiträge zu GPS-Kampagnen des Scientific Committee on Antarctic Research (SCAR) 1995-1998 / R. Dietrich (2000)PermalinkGeodetic applications of the global navigation satellite system (GLONASS) and of GLONASS-GPS combinations / H. Habrich (2000)PermalinkPermalinkIGEX, International GLONASS Experiment : scientific objectives and preparation / Pascal Willis in Advances in space research, vol 23 n° 4 (01/10/1999)Permalink