Multi-pixel Calibration of a Distributed Energy Water Balance Model Using Satellite Data of Land Surface Temperature and Eddy Covariance Data

Abstract

Distributed hydrological models of energy and mass balance usually need in input many soil and vegetation parameters, which are usually difficult to define. This paper will try to approach this problem performing a parameters calibration based on satellite land surface temperature data (LST) as a complementary method to the traditional calibration with ground data.A pixel to pixel calibration procedure of soil hydraulic and vegetation parameters for each pixel of the domain is proposed according to the comparison between observed and simulated land surface temperature.A distributed hydrological model, FEST-EWB, that solves the system of energy and mass balance equations as a function of the representative equilibrium temperature (RET) will be used. RET is comparable to the land surface temperature as retrieved from operational remote sensing data. LST is a critical model state variable and remote sensing LST can be effectively used, in combination with energy and mass balance modeling, to monitor latent and sensible heat fluxes. The analyses are performed over the Consorzio Muzza basin for an area that covers 74,000ha in the middle of the Po Valley, near Lodi city.The reliability of the hydrological model estimates will be evaluated against measurements of latent heat flux and soil moisture acquired by an eddy-covariance station.Moreover, distributed evapotranspiration estimates will be compared with the results obtained from a simplified version of FEST-WB model with computes crop evapotranspiration with Hargreaves equation and crop coefficient values.