A new approach to thermal inertia determination using NOAA-AVHRR data: Application to the Iberian Peninsula

摘要

The thermal inertia, P, is denned as a measure of the resistance offered by materials to change their temperature. P is the most important single thermal property which governs surface temperature variation. Therefore thermal inertia is of great interest to geological and hydrological studies and climate modeling. An attractive and unique way to map and monitoring this parameter over large scale is to use space observation from satellite in the visible and thermal infrared bands. In this paper we present a new algorithm, based on Xue and Cracknell's model, which allows to obtain the thermal inertia combining afternoon and morning NOAA satellites. The algorithm was tested with a set of measurements made on a region of Niger in the frame of HAPEX-Sahel experiment. The behaviour of the model was analyzed by comparing the predicted surface temperatures with the measured ones every ten minutes along the daytime, and by comparing the predicted and measured maximum and minimum surface temperature valuesas well as their times in the daytime. Our results indicate that for the 90 per cent of the cases the absolute difference between predicted and measured surface temperature is lower than 2 K, with a standard deviation of 1.5 K that improves to 1 K whenpredicting the maximum and minimum surface temperatures. In this situation the FTM predicts also their respective times with a standard deviation lower than 30 minutes, this makes possible building images of minimum surface temperature and their date from NOAA data. This fact is of great interest in the case of frosting with clear sky conditions. Following the proposed algorithm a map of thermal inertia of the Iberian peninsula is presented. The results are consistent with the known properties of this area.