Towards an operational daily soil moisutre index derived from combination of MODIS, ASAR and AMSR-E data

Abstract

This work aims at deriving a methodology for calculation of a soil moisture index based on the apparent thermal inertia (ATI) approach. For the processing, MODIS images have been exploited which have a higher resolution (1 km) if compared with METEOSAT images and are suitable for the ATI calculation. Furthermore, the approach considers the soil moisture estimates derived from SAR sensors and use them to calibrate the information coming from the optical data. The main advantage of this approach is to transform a soil moisture index derived from optical images in soil moisture values by using a comparison between spatial distributed data. In order to make the calibration more robust and consider the variability from different areas, three main test sites have been chosen located in Italian regions with different meteorological and landscape characteristics. In case of anomalous values due to the not appropriate acquisition time, AMSRE soil moisture data are used as prior information in order to improve the estimates.