Energy balance modeling of agricultural areas by remote sensing

Abstract

The integrated water resource management required to face the water scarcity situation in semiarid regions relies on the ability to obtain accurate information about the use of water by crops and natural vegetation. Thermal remote sensing provides key data about the vegetation water status. The integration of this remotely sensed data into water and energy balance models help to better estimate evapotranspiration under heterogeneous cropping and natural vegetation patterns, extending the field of application of these models from point to basin and regional scales. In this work, we present an approach to estimate spatially distributed surface energy fluxes using a series of Landsat TM satellite images combined with simulation modeling and ground-based measurements. A physically-based method for the energy budget partitioning following the Two Source Model [1, 2] has been applied over an heterogeneous agricultural area located in southern Spain. The study was performed during 2009 crop growing season and the results were validated with field data collected with an eddy covariance system installed over a corn field during the season. The instantaneous and daily estimations were compared to the measured data, obtaining a general good adjustment at both scales and setting the basis for a larger scale application that may assist a decision - making tool for water resources planning in the region.