Improving of the thermal mapping of coastal and river waters obtained from satellite remote sensing

The temperature of coastal and river water is very important in various areas of environmental concern. Very often, the heat released by human activities in water bodies is classified as a pollutant and it is subjected to regulatory. Remote sensing images acquired by the satellite sensor ASTER could be a very valuable tool in this area. Nevertheless, the spatial resolution (90 m) of this sensor in the thermal infrared is very important limiting factor for the compute of temperature of narrow watercourses or of coastal waters. In this work, an algorithm for the improvement of ASTER images acquired in the TIR based on information on the type of coverage of the area extracted from ASTER images acquired in the VIS-NIR and with spatial resolution varying between 15 m and 30 m. The algorithm produces a downscaling of the ASTER TIR images, from 90 m to 30 m, more complete than those obtainable by usual interpolation techniques. In this paper it is given a summary description of the structure of the algorithm followed by two applications on the coastal areas of the lagoon of Venice and the Po River delta.