ASSIMILATION OF SOIL-MOISTURE INFERRED FROM INFRARED REMOTE-SENSING IN A HYDROLOGICAL MODEL OVER THE HAPEX-MOBILHY REGION

Hydrological models are generally unable to simulate correctly water exchanges at the soil-atmosphere interface and the time evolution of surface soil humidity. This drawback often leads to poor simulation of water flows after periods of low flows because of the wrong estimation of the surface soil water content. In this paper, we describe how remote sensing can be used to account for the vegetation in the estimation of the actual evapotranspiration, and to estimate soil moisture regularly throughout the year and use it to correct the model simulation. This work has been done on the Adour river basin, in the framework of the HAPEX-MOBILHY experiment. The results presented show the improvements that result from the use of remote sensing data in hydrological modelling: better simulation of the soil moisture and of water flows at the outlets, and more realistic calculation of evaporation.