Vol. 6, No. 1, 38-46, 2007

Abstract
This study is aimed at demonstrating the feasibility of the MODIS Land Surface Temperature (LST) product as a source for calculating spatially distributed daily mean air temperature to be used as input for hydrological or environmental models. The test area is located in the Italian Alpine area. The proposed procedure solves, by empirical approaches, the problem of relating LST to the Air Temperature (T_air) and instantaneous T_air values to daily mean values, exploiting ground data weather station measurements as a reference. The relationship between LST and T_air is determined by correlation analysis and equation generalisation for spatial distribution. The extrapolation of daily mean values of T_air from instantaneous values is addressed again by correlation analyses taking into account the altitude variability and exploiting historical series. Validation was accomplished by accuracy assessment procedures both punctual and spatially distributed, the latter performed by comparison with the Inverse Distance Weighting (IDW) interpolation method.

The proposed methodology produced satisfactory results as related to the objective: The daily mean air temperatures derived by LST showing an overall RMSE of 1.89°C, and slightly outperforms the interpolation method used as comparison.

ISSN 1729-3782