TESTING THE EFFECT OF A 2-WAY-COUPLING OF A METEOROLOGICAL AND A HYDROLOGIC MODEL ON THE PREDICTED LOCAL WEATHER

A land-surface module to couple a meteorological and a hydrologic mode l was developed to simulate the water cycle in a closed manner. The mo dule allows to consider the hydrologic processes of the river catchmen t (translation, retention, lateral discharge) in the meteorological mo del which itself drives the hydrologic model by predicted evapotranspi ration and precipitation. Besides this two-way-coupling, the module al lows to consider subgrid-scale surface processes and to heterogenize p recipitation in the meteorological model. The results of 24-h simulati ons with and without a two-way-coupling of the models substantiate tha t even on a short time scale surface runoff and lateral water flows af fect soil wetness, soil temperature, cloudiness and the thermal regime of the atmospheric boundary layer within the catchment. As expected, the coupling results in a slight trend towards moister valleys and dri er hills. (C) 1997 Elsevier Science B.V.