Soil Surface Moisture From EnviSat RA-2: From Modelling Towards Implementation
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This paper presents the current status of ongoing research into the extraction of soil surface moisture data from Radar Altimeter backscatter. One of the motivations for this work is to facilitate comparisons with GRACE data over specific targets such as the Okavango Delta.
Natural land targets for the monitoring of Radar Altimeter backscatter have previously been identified and modelled, utilising data provided by the ERS-1 Geodetic and 35-day Missions. These spatial models have been employed for cross-calibration between ERS-1/2 ice and ocean mode sigma0. The inherent variability of all but a few desert regions meant that the original techniques could not be used beyond these calibration zones.
A new automated technique has made it possible to develop models of wetter regions with the aim of taking these models as close to “dry earth” conditions as possible.
In parallel with this process a semi-empirical model of Radar Altimeter backscatter, which makes use of engineering and scientific parameters, has been developed and is undergoing final calibration.
The use of the spatial models in conjunction with the new semi-empirical backscatter model will enable predictions of soil surface moisture levels using values provided by EnviSat RA-2 backscatter.
KeywordsSigma0 Model Soil Surface Moisture Okavango Delta Radar Altimeter Grace Data
The authors would like to thank the European Space Agency for providing the ERS and Envisat data used in this study.
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