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Improving the spatial bias correction algorithm in SMOS image reconstruction processor : validation of soil moisture retrievals with in situ data / Ali Khazaal in IEEE Transactions on geoscience and remote sensing, vol 57 n° 1 (January 2019)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 57 n° 1 (January 2019) . - pp 277 - 290 Titre : Improving the spatial bias correction algorithm in SMOS image reconstruction processor : validation of soil moisture retrievals with in situ data Type de document : Article/Communication Auteurs : Ali Khazaal, Auteur ; Philippe Richaume, Auteur ; François Cabot, Auteur ; Eric Anterrieu, Auteur ; Arnaud Mialon, Auteur ; Yann H. Kerr, Auteur Année de publication : 2019 Article en page(s) : pp 277 - 290 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] correction d'image [Termes IGN] erreur systématique [Termes IGN] humidité du sol [Termes IGN] image SMOS [Termes IGN] résidu [Termes IGN] télédétection en hyperfréquence [Termes IGN] température de luminance Résumé : (Auteur) SMOS is a space mission led by the European Space Agency and designed to provide global maps of Soil Moisture and Ocean salinity, two important geophysical parameters for understanding the water cycle variations and climate change. The SMOS payload is a 2-D interferometer operating at L-band that consists of 69 elementary antennas located along a Y-shaped structure. Important spatial biases persist in the retrieved brightness temperature (BT) images mainly due to the phenomenon of aliasing inside the field of view of SMOS but also due to the Gibbs oscillations near land/ocean transitions. To minimize these biases, a differential image reconstruction algorithm is used in the operational processor that reduces the contrast of the image to be retrieved. To do that, the contribution of a constant artificial temperature map is removed from the measurements prior to reconstruction and then added back after the reconstruction. In this paper, we show that strong residual biases are still present in the retrieved images. To reduce them, we propose to improve the bias correction algorithm by using a more realistic artificial temperature scene based on separating the land and ocean regions and assigning a constant temperature over land and a Fresnel BT model over the ocean. The artificial scene is also improved by means of representing each pixel by its water fraction percentage to smooth the land/ocean transitions. The improved algorithm is validated over the ocean by comparing the retrieved temperatures to a forward geophysical model but also over land by comparing the retrieved soil moisture to in situ measurements. Numéro de notice : A2019-106 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2018.2853619 Date de publication en ligne : 09/08/2018 En ligne : https://doi.org/10.1109/TGRS.2018.2853619 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92412 [article]

The soil moisture and ocean salinity (SMOS) mission: first results and achievements / Yann H. Kerr in Revue Française de Photogrammétrie et de Télédétection, n° 200 (Novembre 2012)  

Public [article]  inRevue Française de Photogrammétrie et de Télédétection > n° 200 (Novembre 2012) . - pp 12 - 19 Titre : The soil moisture and ocean salinity (SMOS) mission: first results and achievements Type de document : Article/Communication Auteurs : Yann H. Kerr, Auteur ; P. Waldteufel, Auteur ; Jean-Pierre Wigneron, Auteur ; J. Boutin, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 12 - 19 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Missions spatiales [Termes IGN] aérosol [Termes IGN] bande L [Termes IGN] humidité du sol [Termes IGN] hydrosphère [Termes IGN] image SMOS [Termes IGN] océanographie spatiale [Termes IGN] salinité Résumé : (Auteur) The SMOS (Soil Moisture and Ocean Salinity) satellite was successfully launched in November 2009. This ESA led mission for Earth Observation is dedicated to providing soil moisture over continental surface (with an accuracy goal of 0.04 nf/nf) and ocean salinity (with a goal of 0.1 psu). These two geophysical features are important as they control the energy balance between the surface and the atmosphere. Their knowledge is of interest at global scales for climatic and weather research in particular for improving model forecasts. But it also has impact on various domains, ranging from hurricane monitoring to water resource management. The first six months after the launch, the so called commissioning phase, was dedicated to testing the functionalities of the spacecraft, the instrument and the ground segment including data processing. This phase was successfully completed in May 2010, and SMOS has since been in the routine operation phase, providing data products for the scientific community for over two years. The instrument performance and data quality fit the specifications. However, radio frequency interferences have been detected over large parts of Europe, China, Southern Asia, and the Middle East. The generation of Level 2 soil moisture and ocean salinity data is an on-going activity with continuously improved processings. Numéro de notice : A2012-563 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : 10.52638/rfpt.2012.57 En ligne : https://doi.org/10.52638/rfpt.2012.57 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32009 [article]

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018-2012041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

ESA's Soil Moisture and Ocean Salinity mission : mission performance and operations / S. Mecklenburg in IEEE Transactions on geoscience and remote sensing, vol 50 n° 5 Tome 1 (May 2012)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 50 n° 5 Tome 1 (May 2012) . - pp 1354 - 1366 Titre : ESA's Soil Moisture and Ocean Salinity mission : mission performance and operations Type de document : Article/Communication Auteurs : S. Mecklenburg, Auteur ; M. Drusch, Auteur ; Yann H. Kerr, Auteur ; J. Font, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 1354 - 1366 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] image SMOS [Termes IGN] interférence [Termes IGN] mission spatiale [Termes IGN] performance [Termes IGN] SMOS [Termes IGN] température de luminance Résumé : (Auteur) The European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission was launched on the 2nd of November 2009. The first six months after launch, the so-called commissioning phase, were dedicated to test the functionalities of the spacecraft, the instrument, and the ground segment including the data processors. This phase was successfully completed in May 2010, and SMOS has since been in the routine operations phase and providing data products to the science community for over a year. The performance of the instrument has been within specifications. A parallel processing chain has been providing brightness temperatures in near-real time to operational centers, e.g., the European Centre for Medium-Range Weather Forecasts. Data quality has been within specifications; however, radio-frequency interference (RFI) has been detected over large parts of Europe, China, Southern Asia, and the Middle East. Detecting and flagging contaminated observations remains a challenge as well as contacting national authorities to localize and eliminate RFI sources emitting in the protected band. The generation of Level 2 soil moisture and ocean salinity data is an ongoing activity with continuously improved processors. This article will summarize the mission status after one year of operations and present selected first results. Numéro de notice : A2012-205 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2012.2187666 Date de publication en ligne : 03/04/2012 En ligne : https://doi.org/10.1109/TGRS.2012.2187666 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31652 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-2012051A	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Evaluation of SMOS soil moisture products over continental U.S. using the SCAN/SNOTEL network / A. Al Bitar in IEEE Transactions on geoscience and remote sensing, vol 50 n° 5 Tome 1 (May 2012)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 50 n° 5 Tome 1 (May 2012) . - pp 1572 - 1586 Titre : Evaluation of SMOS soil moisture products over continental U.S. using the SCAN/SNOTEL network Type de document : Article/Communication Auteurs : A. Al Bitar, Auteur ; D. Leroux, Auteur ; Yann H. Kerr, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 1572 - 1586 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] bande L [Termes IGN] Etats-Unis [Termes IGN] humidité du sol [Termes IGN] image SMOS [Termes IGN] validation des données [Termes IGN] zone humide Résumé : (Auteur) The Soil Moisture and Ocean Salinity (SMOS) satellite has opened the era of soil moisture products from passive L-band observations. In this paper, validation of SMOS products over continental U.S. is done by using the Soil Climate Analysis Network (SCAN)/SNOwpack TELemetry (SNOTEL) soil moisture monitoring stations. The SMOS operational products and the SMOS reprocessing products are both used and compared over year 2010. First, a direct node-to-site comparison is performed by taking advantage of the oversampling of the SMOS product grid. The comparison is performed over several adjacent nodes to site, and several representative couples of site-node are identified. The impact of forest fraction is shown through the analysis of different cases across the U.S. Also, the impact of water fraction is shown through two examples in Florida and in Utah close to Great Salt Lake. A radiometric aggregation approach based on the antenna footprint and spatial description is used. A global comparison of the SCAN/SNOTEL versus SMOS is made. Statistics show an underestimation of the soil moisture from SMOS compared to the SCAN/SNOTEL local measurements. The results suggest that SMOS meets the mission requirement of 0.04 m3/m3 over specific nominal cases, but differences are observed over many sites and need to be addressed. Numéro de notice : A2012-208 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2012.2186581 Date de publication en ligne : 04/04/2012 En ligne : https://doi.org/10.1109/TGRS.2012.2186581 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31655 [article]

Exemplaires(1)

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065-2012051A	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Evaluating an improved parameterization of the soil emission in L-MEB / Jean-Pierre Wigneron in IEEE Transactions on geoscience and remote sensing, vol 49 n° 4 (April 2011)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 49 n° 4 (April 2011) . - pp 1177 - 1189 Titre : Evaluating an improved parameterization of the soil emission in L-MEB Type de document : Article/Communication Auteurs : Jean-Pierre Wigneron, Auteur ; A. Chanzy, Auteur ; Yann H. Kerr, Auteur ; et al., Auteur Année de publication : 2011 Article en page(s) : pp 1177 - 1189 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] bande L [Termes IGN] biosphère [Termes IGN] emissivité [Termes IGN] étalonnage de modèle [Termes IGN] humidité du sol [Termes IGN] rugosité du sol [Termes IGN] télédétection en hyperfréquence Résumé : (Auteur) In the forward model [L-band microwave emission of the biosphere (L-MEB)] used in the Soil Moisture and Ocean Salinity level-2 retrieval algorithm, modeling of the roughness effects is based on a simple semiempirical approach using three main “roughness” model parameters: HR, QR, and NR. In many studies, the two parameters QR and NR are set to zero. However, recent results in the literature showed that this is too approximate to accurately simulate the microwave emission of the rough soil surfaces at L-band. To investigate this, a reanalysis of the PORTOS-93 data set was carried out in this paper, considering a large range of roughness conditions. First, the results confirmed that QR could be set to zero. Second, a refinement of the L-MEB soil model, considering values of NR for both polarizations (namely, NRV and NRH), improved the model accuracy. Furthermore, simple calibrations relating the retrieved values of the roughness model parameters HR and (NRH - NRV) to the standard deviation of the surface height were developed. This new calibration of L-MEB provided a good accuracy (better than 5 K) over a large range of soil roughness and moisture conditions of the PORTOS-93 data set. Conversely, the calibrations of the roughness effects based on the Choudhury approach, which is still widely used, provided unrealistic values of surface emissivities for medium or large roughness conditions. Numéro de notice : A2011-130 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2010.2075935 Date de publication en ligne : 09/11/2010 En ligne : https://doi.org/10.1109/TGRS.2010.2075935 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30909 [article]

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Exploring the water cycle of the 'blue planet': the Soil Moisture and Ocean Salinity (SMOS) mission / M. Drinkwater in ESA bulletin, n° 137 (February 2009)  

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Star in the sky, the SMOS playload: MIRAS / M. Drinkwater in ESA bulletin, n° 137 (February 2009)  

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Phenomenological analysis of simulated signals observed over shaded areas in an urban scene / Christophe Miesch in IEEE Transactions on geoscience and remote sensing, vol 42 n° 2 (February 2004)  

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Use of meteorological satellites for water balance monitoring in sahelian regions / B. Seguin in International Journal of Remote Sensing IJRS, vol 10 n° 6 (June 1989)  

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NOAA AVHRR and its uses for rainfall and evapotranspiration monitoring / Yann H. Kerr in International Journal of Remote Sensing IJRS, vol 10 n°4-5 (May 1989)  

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