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DOI: 10.1109/TGRS.2011.2179051

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IEEE Transactions on Geoscience and Remote Sensing 50, 5 (2012) 1404-1413

A combined optical-microwave method to retrieve soil moisture over vegetated areas

C. Mattar (  Corresponding author ) 1, J.-P. Wigneron 2, J.A. Sobrino 1, N. Novello 2, J.-C. Calvet 3, C. Albergel 4, P. Richaume 5, A. Mialon 5, D. Guyon 2, J.C. Jimenez-Munoz 1, Y.H. Kerr 5

(2012)

A simple approach for correcting for the effect of vegetation in the estimation of the surface soil moisture (wS) from L-band passive microwave observations is presented in this study. The approach is based on semi-empirical relationships between soil moisture and the polarized reflectivity including the effect of the vegetation optical depth which is parameterized as a function of the normalized vegetation difference index (NDVI). The method was tested against in situ measurements collected over a grass site from 2004 to 2007 (SMOSREX experiment). Two polarizations (horizontal/vertical) and five incidence angles (20◦, 30◦, 40◦, 50◦, and 60◦) were considered in the analysis. The best wS estimations were obtained when using both polarizations at an angle of 40◦. The average accuracy in the soil moisture retrievals was found to be approximately 0.06 m3/m3, improving the estimations by 0.02 m3/m3 with respect to the case in which the vegetation effect is not considered. The results indicate that information on vegetation (through a vegetation index such as NDVI) is useful for the estimation of soil moisture through the semi-empirical regressions.

1:	Department of Thermodynamics, Faculty of Physics
	Universidad de Valencia
2:	Écologie fonctionnelle et physique de l'environnement (EPHYSE - UR1263)
	Institut national de la recherche agronomique (INRA) : UR1263
3:	Groupe d'étude de l'atmosphère météorologique (CNRM-GAME)
	CNRS : URA1357 – INSU – Météo France
4:	European Centre for Medium Range Weather Forecast (ECMWF)
	ECMWF
5:	Centre d'études spatiales de la biosphère (CESBIO)
	CNRS : UMR5126 – Institut de recherche pour le développement [IRD] – CNES – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III

subject

:

Life Sciences/Ecology, environment/Ecosystems

keyword(s): L-band – microwave radiometry – normalized vegetation difference index (NDVI) – soil moisture (SM) – surface temperature.

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From: Dominique Bruel <>

Submitted on: Thursday, 24 May 2012 11:21:11

Updated on: Friday, 25 May 2012 09:43:28