Calibration of a Distributed Hydrological Model using Satellite Data of LST and Ground Discharge Measurements
Corbari, Chiara1; Mancini, Marco1; Li, Jiren2; Su, Zhongbo3
1Politecnico di Milano, ITALY; 2China Institute of Water Resources and Hydropower Research, CHINA; 3University of Twente, NETHERLANDS
Calibration and validation of distributed models at basin scale generally refer to external variables, which are integrated catchment model outputs, and usually depend on the comparison between simulated and observed discharges at the available rivers cross sections, which are usually very few. However distributed models allow an internal validation due to their intrinsic structure, so that internal processes and variables of the model can be controlled in each cell of the domain. In particular this work investigates the potentiality to control evapotranspiration and its spatial and temporal variability through the detection of land surface temperature from satellite remote sensing. This study proposes a methodology for the calibration of distributed hydrological models at basin scale through the constraints on an internal model variable using remote sensing data of land surface temperature. The model (FEST-EWB) algorithm solves the system of energy and mass balances in term of the equilibrium pixel temperature or representative equilibrium temperature that governs the fluxes of energy and mass over the basin domain. This equilibrium surface temperature, which is a critical model state variable, is compared to land surface temperature from MODIS and AATSR. So soil hydraulic parameters and vegetation variables will be calibrated according to the comparison between observed and simulated land surface temperature minimizing the errors. A similar procedure will also be applied performing the traditional calibration using only discharge measurements.
These analyses are performed for Upper Yangtze River basin (China) in framework of DRAGON-2 and DRAGON-3 Programme funded by NRSCC and ESA.