SMOS-IC: an alternative SMOS soil moisture and 3 vegetation optical depth product
FERNÁNDEZ-MORÁN, Roberto
Interactions Sol Plante Atmosphère [UMR ISPA]
Universitat de València = University of Valencia [UV]
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Interactions Sol Plante Atmosphère [UMR ISPA]
Universitat de València = University of Valencia [UV]
FERNÁNDEZ-MORÁN, Roberto
Interactions Sol Plante Atmosphère [UMR ISPA]
Universitat de València = University of Valencia [UV]
< Réduire
Interactions Sol Plante Atmosphère [UMR ISPA]
Universitat de València = University of Valencia [UV]
Langue
en
Document de travail - Pré-publication
Ce document a été publié dans
2017
Résumé en anglais
The main goal of the Soil Moisture and Ocean Salinity (SMOS) mission over land surfaces is the production of global maps of soil moisture (SM) and vegetation optical depth (τ) based on multi-angular brightness temperature ...Lire la suite >
The main goal of the Soil Moisture and Ocean Salinity (SMOS) mission over land surfaces is the production of global maps of soil moisture (SM) and vegetation optical depth (τ) based on multi-angular brightness temperature (TB) measurements at L-band. The operational SMOS Level 2 and Level 3 soil moisture algorithms account for different surface effects, such as vegetation opacity and soil roughness at 4 km resolution, in order to produce global retrievals of SM and τ. In this study, we present an alternative SMOS product which was developed by INRA (Institut National de la Recherche Agronomique) and CESBIO (Centre d’Etudes Spatiales de la BIOsphère). This SMOS-INRA-CESBIO (SMOS-IC) product provides daily SM and τ at the global scale and differs from the operational SMOS Level 3 (SMOSL3) product in the treatment of retrievals over heterogeneous pixels. Specifically, SMOS-IC is much simpler and does not account for corrections associated to the antenna pattern and the complex SMOS viewing angle geometry. It considers pixels as homogeneous to avoid uncertainties and errors linked to inconsistent auxiliary data sets which are used to characterize the pixel heterogeneity in the SMOS L3 algorithm. SMOS-IC also differs from the current SMOSL3 product (Version 300, V300) in the values of the effective vegetation scattering albedo (ω) and soil roughness parameters. An inter-comparison is presented in this study based on the use of ECMWF (European Center for Medium range Weather Forecasting) SM outputs and NDVI (Normalized Difference Vegetation Index) from MODIS (Moderate-Resolution Imaging Spectroradiometer). A 6 year (2010-2015) inter-comparison of the SMOS products SMOS-IC and SMOSL3 SM (V300) with ECMWF SM yielded higher correlations and lower ubRMSD (unbiased root mean square difference) for SMOS-IC over most of the pixels. In terms of τ, SMOS-IC τ was found to be better correlated to MODIS NDVI in most regions of the globe, with the exception of the Amazonian basin and of the northern mid-latitudes.< Réduire
Mots clés
SMOS
SMOS-IC
soil moisture
NDVI
Mots clés en anglais
L-band
Level 3
ECMWF
vegetation optical depth
MODIS
Origine
Importé de halUnités de recherche