EVALUATION OF THE REPRODUCIBILITY OF RIVER DISCHARGE WITH DIFFERENT PRECIPITATION DATA IN JAPAN

Abstract

 The accuracy of the meteorological input data is important for the proper reproduction of the water cycle. In this study, we conducted model simulations of river discharge for the whole of Japan using the integrated water resources model (H08) driven by three different precipitation data based on climate reanalysis, gauges and radar with gauges, and evaluated the reproducibility of river discharge. Regardless of which precipitation data were used, rivers in northern Japan tended to be underestimated their spring peak discharge. The use of precipitation data generated by densely observed gauges and gauges with radar has been confirmed to improve the reproducibility of river discharge than the use of precipitation derived from climate reanalysis. The accuracy of river discharge is relatively the same between experiments with gauges only and gauges with radar. However, in mountainous areas such as the middle basin of the Tenryu River where the precipitation observation network is insufficient, the use of radar precipitation data is expected to improve the reproducibility.