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Centre d'études spatiales de la biosphère |  |
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Centre d'études spatiales de la biosphère | |
| HAL : hal-00574653, version 1 |
| DOI : 10.1109/TGRS.2010.2075935 |
| Fiche détaillée |  Récupérer au format |
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| IEEE Transactions on Geoscience & Remote Sensing Issue 99 (2011) 1-13 |
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| Evaluating an Improved Parameterization of the Soil Emission in L-MEB |
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Jean Pierre Wigneron 1A. Chanzy 2 |
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| SMOS Collaboration(s) |
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| (08/11/2011) |
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| 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. |
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| 1 : | Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263) |
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Institut national de la recherche agronomique (INRA) : UR1263 |
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| 2 : | UMR Environnement Méditerranéen et Modélisation des AgroHydrosytèmes EMMAH |
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Institut national de la recherche agronomique (INRA) |
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| 3 : | Centre d'études spatiales de la biosphère (CESBIO) |
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CNRS : UMR5126 – Institut de recherche pour le développement [IRD] – CNES – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III |
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| 4 : | Laboratoire de l'intégration, du matériau au système (IMS) |
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CNRS : UMR5218 – Université Sciences et Technologies - Bordeaux I – Institut Polytechnique de Bordeaux |
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| 5 : | Institue for Computational Earth System Science |
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University of California, Santa Barbara |
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| 6 : | Radiophysics of remote sensing laboratory |
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Kirensky Institute of Physics |
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| 7 : | European Centre for Medium Range Weather Forecast (ECMWF) |
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ECMWF |
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| Domaine | : | Sciences de l'ingénieur/Electromagnétisme Planète et Univers/Sciences de la Terre Physique/Physique/Géophysique Planète et Univers/Sciences de la Terre/Géophysique |
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| Geophysical measurements – L-band – Microwave remote sensing – Rough surfaces – Soil – Soil Moisture and Ocean Salinity (SMOS) – Soil measurements – Surface roughness – Temperature measurement – radiometry – roughness – soil moisture (SM) – soil surface |
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| hal-00574653, version 1 | |
| http://hal.archives-ouvertes.fr/hal-00574653 | |
| oai:hal.archives-ouvertes.fr:hal-00574653 | |
| Contributeur : François Demontoux | |
| Soumis le : Mardi 8 Mars 2011, 15:34:03 | |
| Dernière modification le : Mardi 8 Mars 2011, 15:34:03 | |
