Soil moisture modelling of a SMOS pixel: interest of using the PERSIANN database over the Valencia Anchor Station

Abstract

Abstract. In the framework of Soil Moisture and Ocean Salinity (SMOS) Calibration/Validation (Cal/Val) activities, this study addresses the use of the PERSIANN-CCS 1 database in hydrological applications to accurately simulate a whole SMOS pixel by representing the spatial and temporal heterogeneity of the soil moisture fields over a wide area (50×50 km 2 ). The study focuses on the Valencia Anchor Station (VAS) experimental site, in Spain, which is one of the main SMOS Cal/Val sites in Europe.A faithful representation of the soil moisture distribution at SMOS pixel scale (50×50 km 2 ) requires an accurate estimation of the amount and temporal/spatial distribution of precipitation. To quantify the gain of using the comprehensive PERSIANN database instead of sparsely distributed rain gauge measurements, comparisons between in situ observations and satellite rainfall data are done both at point and areal scale. An overestimation of the satellite rainfall amounts is observed in most of the cases (about 66%) but the precipitation occurrences are in general retrieved (about 67%).To simulate the high variability in space and time of surface soil moisture, a Soil Vegetation Atmosphere Transfer (SVAT) model -ISBA (Interactions between Soil Biosphere Atmosphere) is used. The interest of using satellite rainCorrespondence to: S. Juglea

Evaluating Satellite Products for Precipitation Estimation in Mountain Regions: A Case Study for Nepal

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Soil Moisture for Hydrological Applications: Open Questions and New Opportunities

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“…This leads to the deviations between satellite and ground-based measurements. To diminish the deviations, the in situ efforts should focus on separation of the respective contribution of these factors under a broad range of environmental conditions (Bircher et al, 2012;Juglea et al, 2010) before the planned refinement of the retrieval algorithm and data reprocessing (Dente et al, 2012). This should allow one to obtain more consistent data and yield quantitative maps of global soil moisture dynamics that is one of the main objectives of the SMOS mission .…”