Development and evaluation of a simple method to estimate evaporation from satellite data

Abstract

Evaporation is a key factor in climate monitoring, agricultural meteorology, and the validation of climate models, numerical weather prediction models, and hydrological models. Methods using satellite data have the advantage that they provide data with a large, up to global coverage, while surface measurements typically provide local values only. Moreover, the density of surface measurements is usually quite low throughout the world. Hence, in many regions satellite instruments are the only available observation source for the estimation of evaporation. This paper compares different semi-empirical methods for determining potential and actual evaporation from satellite data with a spatial resolution of 0.05 degree over Europe. The results for potential evaporation are compared to data of the network of the Deutscher Wetterdienst in order to evaluate the best method. In a second step satellite-based actual evaporation is compared with data from different land-surface models and observations for the time period from September 2005 to August 2006. The proposed methods provide actual evaporation in good agreement with the other models and observations, but at a higher spatial resolution.