QUANTIFICATION AND MAPPING OF AREAL MEAN PRECIPITATION ERROR USING SATELLITE OBSERVATIONS FOR IMPROVEMENT OF RAIN GAUGE NETWORK IN VIETNAM

摘要

Precipitation would be one of the most important inputs for rainfall-runoff (RR) simulations. Therefore, quantifying the Areal Mean Precipitation (AMP) error is important to give the guidance for improving the accuracy and robustness of RR models. Instead of using limited number of rain gauge measurements, satellite based precipitation data would be a surrogate data source. In this study, the capability of remote sensing precipitation including satellite-only GSMaP-MVK and satellite-gauge merged data to evaluate AMP uncertainty is investigated. The adjusted precipitation performances depend upon the number of blended rain gauges, which would not always give superior results than the original data GSMaP-MVK.In addition GSMaP-MVK would be one of the choices for precipitation data source to compute AMP error. Therefore, a map of potential AMP uncertainty in major rivers in Vietnam is produced and utilized for improvement of rain gauge network. In order to ensure the fidelity of stream-flow simulation, rain gauge networks in 10 river basins in Vietnam are suggested to be upgraded for a total of 18 rain gauges. The rain gauge network in three river basins in Central of Vietnam Thach Han, Tam Ky and Lai Giang should be given the highest priority, due to their relatively high AMP uncertainty.