A new river flooding scheme for global climate applications: Off-line evaluation over South America

International audienceGiven their strong interaction with both climate and the carbon cycle, wetlands and surface waters need to be parameterized in global general circulation models. For this purpose, a new simple flooding river scheme is proposed and evaluated over South America. The flood dynamics is described through the coupling between the ISBA land surface model and the TRIP river routing model including a prognostic flood reservoir. This reservoir fills when the river height exceeds a critical value and vice versa. The reservoir interacts with the soil hydrology through infiltration and with the overlying atmosphere through precipitation interception and free water surface evaporation. The model is tested in off-line mode using the 10-year ISLSCP-2 atmospheric forcing. The evaluation is made against satellite-derived inundation estimates as well as in situ river discharge observations. Besides a basin-scale increase in annual surface evaporation, the results show improved monthly discharges over the Amazon and Parana rivers, as well as a reasonable agreement between the simulated flooded areas and satellite-derived inundation estimates