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Soil moisture experiment 2004 (SMEX04) (Bulletin de Remote sensing of environment) / Thomas J. Jackson

Public [n° ou bulletin]  Titre : Soil moisture experiment 2004 (SMEX04) Type de document : Périodique Auteurs : Thomas J. Jackson, Editeur scientifique ; S. Moran, Editeur scientifique ; P. O'neill, Editeur scientifique Editeur : Amsterdam [Pays Bas] : Elsevier Année de publication : 2008 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Télédétection [Termes IGN] humidité du sol [Termes IGN] SOIL MOISTURE EXPERIMENT Numéro de notice : 110-0802 Thématique : IMAGERIE Nature : Numéro de périodique Permalink : https://documentation.ensg.eu/index.php?lvl=bulletin_display&id=10445 [n° ou bulletin]

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• Spatial sampling uncertainty in SMEX04 soil moisture fields: a data-based resampling experiment / M. Gebremichael in Remote sensing of environment, vol 112 n° 2 (15/02/2008)

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Spatial sampling uncertainty in SMEX04 soil moisture fields: a data-based resampling experiment / M. Gebremichael in Remote sensing of environment, vol 112 n° 2 (15/02/2008)

Public [article]  inRemote sensing of environment > vol 112 n° 2 (15/02/2008) . - pp 326 - 336 Titre : Spatial sampling uncertainty in SMEX04 soil moisture fields: a data-based resampling experiment Type de document : Article/Communication Auteurs : M. Gebremichael, Auteur ; E.R. Vivoni, Auteur Année de publication : 2008 Article en page(s) : pp 326 - 336 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] échantillonnage d'image [Termes IGN] humidité du sol [Termes IGN] image aérienne [Termes IGN] image PSR [Termes IGN] image radar [Termes IGN] incertitude des données [Termes IGN] Mexico (Mexique) [Termes IGN] SOIL MOISTURE EXPERIMENT Résumé : (Auteur) A data-based resampling experiment is performed to estimate sampling errors of area-averaged soil moisture estimates due to spatial sampling by ground-based sensors. The data consists of high-resolution soil moisture images derived from the Polarimetric Scanning Radiometer (PSR/CX) sensor flown on an aircraft as part of the summer field experiment (SMEX04 — Soil Moisture Experiment 2004) in the monsoon region of Sonora, Mexico. The sampling characteristics are investigated by accounting for random networks and evenly spaced networks. For random network designs, we develop a simple model that can be used to estimate the sampling uncertainty (expressed as standard deviation of sampling error as a percentage of the areal mean soil moisture) as a function of the number of sensors, mean soil moisture content and averaging area. This model is valid for five or more sensors. The model should prove useful to those wishing to assess the area-averaged performance of a soil moisture network. Furthermore, the method of analysis is applicable to other study regions (Oklahoma, Iowa, Alabama, Georgia, and Arizona) where soil moisture fields have been mapped at high resolution using airborne passive microwave remote sensors. Copyright Elsevier Numéro de notice : A2008-035 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29030 [article]

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High-resolution change estimation of soil moisture using L-band radiometer and Radar observations made during the SMEX02 experiments / U. Narayan in IEEE Transactions on geoscience and remote sensing, vol 44 n° 6 (June 2006)

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 44 n° 6 (June 2006) . - pp 1545 - 1554 Titre : High-resolution change estimation of soil moisture using L-band radiometer and Radar observations made during the SMEX02 experiments Type de document : Article/Communication Auteurs : U. Narayan, Auteur ; V. Lakshmi, Auteur ; Thomas J. Jackson, Auteur Année de publication : 2006 Article en page(s) : pp 1545 - 1554 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] bande L [Termes IGN] coefficient de rétrodiffusion [Termes IGN] détection de changement [Termes IGN] humidité du sol [Termes IGN] image AIRSAR [Termes IGN] image ALOS [Termes IGN] Iowa (Etats-Unis) [Termes IGN] limite de résolution radiométrique [Termes IGN] radiomètre à hyperfréquence [Termes IGN] rugosité du sol [Termes IGN] simulation numérique [Termes IGN] SOIL MOISTURE EXPERIMENT [Termes IGN] température de luminance Résumé : (Auteur) The soil moisture experiments held during June-July 2002 (SMEX02) at lowa demonstrated the potential of the L-band radiometer (PALS) in estimation of near surface soil moisture under dense vegetation canopy conditions. The L-band radar was also shown to be sensitive to near surface soil moisture. However, the spatial resolution of a typical satellite L-band radiometer is of the order of tens of kilometers, which is not sufficient to serve the full range of science needs for land surface hydrology and weather modeling applications. Disaggregation schemes for deriving subpixel estimates of soil moisture from radiometer data using higher resolution radar observations may provide the means for making available global soil moisture observations at a much finer scale. This paper presents a simple approach for estimation of change in soil moisture at a higher (radar) spatial resolution by combining L-band copolarized radar backscattering coefficients and L-band radiometric brightness temperatures. Sensitivity of AIRSAR L-band copolarized channels has been demonstrated by comparison with in situ soil moisture measurements as well as PALS brightness temperatures. The change estimation algorithm has been applied to coincident PALS and AIRSAR datasets acquired during the SMEX02 campaign. Using AIRSAR data aggregated to a 100-m resolution, PALS radiometer estimates of soil moisture change at a 400-m resolution have been disaggregated to 100-m resolution. The effect of surface roughness variability on the change estimation algorithm has been explained using integral equation model (IEM) simulations. A simulation experiment using synthetic data has been performed to analyze the performance of the algorithm over a region undergoing gradual wetting and dry down. Copyright IEEE Numéro de notice : A2006-260 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27987 [article]

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Utilizing calibrated GPS reflected signals to estimate soil reflectivity and dielectric constant: results from SMEX02 / S.J. Katzberg in Remote sensing of environment, vol 100 n° 1 (15/01/2006)

Public [article]  inRemote sensing of environment > vol 100 n° 1 (15/01/2006) . - pp 17 - 28 Titre : Utilizing calibrated GPS reflected signals to estimate soil reflectivity and dielectric constant: results from SMEX02 Type de document : Article/Communication Auteurs : S.J. Katzberg, Auteur ; O. Torres, Auteur ; et al., Auteur Année de publication : 2006 Article en page(s) : pp 17 - 28 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] bande L [Termes IGN] constante diélectrique [Termes IGN] données de terrain [Termes IGN] étalonnage géométrique [Termes IGN] humidité du sol [Termes IGN] Iowa (Etats-Unis) [Termes IGN] réflectance de surface [Termes IGN] réflectivité [Termes IGN] réflexion spéculaire [Termes IGN] signal GPS [Termes IGN] SOIL MOISTURE EXPERIMENT [Termes IGN] sol arable [Termes IGN] télédétection en hyperfréquence Résumé : (Auteur) Extensive reflected GPS data was collected using a GPS reflectometer installed on an HC130 aircraft during the Soil Moisture Experiment 2002 (SMEX02) near Ames, Iowa. At the same time, widespread surface truth data was acquired in the form of point soil moisture profiles, areal sampling of near-surface soil moisture, total green biomass and precipitation history, among others. Previously, there have been no reported efforts to calibrate reflected GPS data sets acquired over land. This paper reports the results of two approaches to calibration of the data that yield consistent results. It is shown that estimating the strength of the reflected signals by either (1) assuming an approximately specular surface reflection or (2) inferring the surface slope probability density and associated normalization constants give essentially the saine results for the conditions encountered in SMEX02. The corrected data is converted to surface reflectivity and then to dielectric constant as a test of the calibration approaches. Utilizing the extensive in-situ soil moisture related data, this paper also presents the results of comparing the GPS-inferred relative dielectric constant with the Wang - Schmugge model frequently used to relate volume moisture content to dielectric constant. It is shown that the calibrated GPS reflectivity estimates follow the expected dependence of permittivity with volume moisture, but with the following qualification: The soil moisture value governing the reflectivity appears to come from only the top 1 - 2 cm of soil, a result consistent with results found for other microwave techniques operating at L-band. Nevertheless, the experimentally derived dielectric constant is generally lower than predicted. Possible explanations are presented to explain this result. Numéro de notice : A2006-014 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27741 [article]

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Land cover-based optimal deconvolution of PALS L-band microwave brightness temperatures / A.S. Limaye in Remote sensing of environment, vol 92 n° 4 (30 September 2004)

Public [article]  inRemote sensing of environment > vol 92 n° 4 (30 September 2004) . - pp 497 - 506 Titre : Land cover-based optimal deconvolution of PALS L-band microwave brightness temperatures Type de document : Article/Communication Auteurs : A.S. Limaye, Auteur ; William L. Crosson, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 497 - 506 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] agriculture [Termes IGN] biomasse [Termes IGN] capteur actif [Termes IGN] capteur passif [Termes IGN] déconvolution [Termes IGN] Glycine max [Termes IGN] Iowa (Etats-Unis) [Termes IGN] luminance lumineuse [Termes IGN] maïs (céréale) [Termes IGN] Passive and Active L and S band Sensor [Termes IGN] SOIL MOISTURE EXPERIMENT [Termes IGN] température de luminance Résumé : (Auteur) An optimal deconvolution (ODC) technique has been developed to estimate microwave brightness temperatures of agricultural fields using microwave radiometer observations. The technique is applied to airborne measurements taken by the Passive and Active L and S band (PALS) sensor in Iowa during Soil Moisture Experiments in 2002 (SMEX02). Agricultural fields in the study area were predominantly soybeans and corn. The brightness temperatures of corn and soybeans were observed to be significantly different because of large differences in vegetation biomass. PALS observations have significant over-sampling; observations were made about 100 m apart and the sensor footprint extends to about 400 m. Conventionally, observations of this type are averaged to produce smooth spatial data fields of brightness temperatures. However, the conventional approach is in contrast to reality in which the brightness temperatures are in fact strongly dependent on land cover, which is characterized by sharp boundaries. In this study, we mathematically deconvolve the observations into brightness temperature at the field scale (500-800 m) using the sensor antenna response function. The result is more accurate spatial representation of field-scale brightness temperatures, which may in turn lead to more accurate soil moisture retrieval. Numéro de notice : A2004-415 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26942 [article]

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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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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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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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