Airborne Land Surface Temperature for a Pixel to Pixel Calibration Procedure of an Energy Water Balance Model in Barrax
Corbari, Chiara1; Mancini, Marco1; Sobrino, JosŤ A.2
1Politecnico di Milano, ITALY; 2University of Valencia, SPAIN
Airborne land surface temperature data are used to implement a pixel to pixel calibration procedure of soil hydraulic and vegetation parameters into a distributed energy-water balance model in the heterogeneous agricultural area of Barrax (Spain). Soil hydraulic parameters have an important role in hydrological models but their spatial definition is still a difficult issue. These parameters are involved in the computation of the principal mass and energy fluxes, so their definition is a crucial step. A distributed hydrological model, Flash-flood Event-based Spatially-distributed rainfall-runoff Transformation- Energy Water Balance model (FEST-EWB) will be used. The model algorithm solves the system of energy and mass balances in terms of the representative equilibrium temperature that is a critical model state variable. This equilibrium surface temperature is compared to remote sensing land surface temperature to calibrate soil hydraulic and vegetation parameters in each single pixel of the study area minimizing the errors. The procedure will be applied to the Barrax agricultural district characterized by a patchwork of cultivated and non cultivated fields using data from two different field campaigns (2005 SEN2FLEX (ESA) and 2011 EODIX experiments) where ground and airborne data have been acquired. Relative and absolute errors on simulated land surface temperature significantly improve from the simulation with the literature values of soil and vegetation parameters to that using the modified parameters. Evapotranspiration estimates improvement is also verified by means of measurements from eddy covariance towers which were installed during the two experiments.