Surface soil moisture evaluation by a multitemporal satellite approach

The Multitemporal Ts-VI (MTVI) method has been proposed as a modified extension of the well known Temperature-Vegetation Dryness Index (TVDI), taking advantage of the self-consistency of TVDI but at the same time trying to overcome its greatest constraint for better characterizing and monitoring surface soil moisture conditions over large and heterogeneous areas and so extending the operational applicability of the Ts-VI relationship. In order to test the performances of the MTVI method, a multitemporal sequence of Landsat TM-ETM+ images, acquired over a wide area in Umbria region (Italy), were selected and processed. The derived MTVI soil moisture maps reveal a better agreement with ground measurements recorded at rain gauge stations, both for a long- (the same month in different years) and a short-term (the same season in different dates) sequence of satellite imagery, than those obtained by the application of the standard Ts-VI method.