On the Use of Coupled Atmospheric and Hydrologic Models at Regional Scale

Abstract

Abstract. The purpose of this study is to present the possibilities offered by coupled atmospheric and hydrologic models as a new tool to validate and interpret results produced by atmospheric models. The advantages offered by streamflow observations are different from those offered by conventional precipitation observations. The dependence between basins and sub-basins can be very useful, and the integrating effect of the large basins facilitates the evaluation of state of-the-art atmospheric models by filtering out some of the spatial and temporal variability that complicate the point-by-point verifications that are more commonly used. The streamflow predicted by the coupled atmospheric-hydrologic model versus the measured streamflow is sufficiently sensitive to clearly assess atmospheric model improvements resulting from increasing horizontal resolution and altering the treatment of precipitation processes in the model. A case study for several southern Ontario river basins is presented with the Watflood hydrologic model developed at the University of Waterloo. It is passively coupled to a nonhydrostatic mesoscale atmospheric model (mc2) that is integratedc at horizontal resolutions of 35, 10 and 3 km. The Watflood model is also driven by radar derived precipitation amounts from King City Radar observations. It is demonstrated that the hydrological model is sufficiently sensitive and accurate to diagnose model and radar errors. This tool brings an additional degree of verification that will be very important in the improvement of technologies associated with atmospheric models, radar observations and the water resources management.KeywordsAtmospheric ModelRadar ObservationRadar ErrorPrecipitation ObservationAtmospheric SimulationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.