Comparison of different satellite rainfall products over the Italian territory

In this study, a preliminary analysis of three satellite-derived rainfall products is carried out in order to evaluate their reliability and accuracy. Specifically, two state-of-art rainfall products are used: the PR-OBS-5 provided by EUMETSAT within the Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF) project and the 3B42-RT product from the Tropical Rainfall Measuring Mission (TRMM) Multiple Precipitation Analysis (TMPA). The third product is obtained by applying a new inversion method, called SM2RAIN, to satellite soil moisture data. In this latter approach, the soil is considered to be a "natural raingauge" that is employed for "measuring" rainfall. As benchmark, quality checked daily rainfall observations throughout the Italian territory for the period 2010-2011 are used. The comparison with ground observations is carried out in terms of correlation coefficients, R, and root mean square error, RMSE. The results show satisfactory R-values (and low RMSEs) between satellite and observed 5-day rainfall data with median R-values greater than 0.50. Moreover, by analyzing the error spatial patterns, and by considering the different temporal resolution of the products, the potential of integrating them in space and time is underlined as this can be expected to further improve the estimation of rainfall for hydrological applications over the Italian territory.