DEVELOPMENT OF A STATISTICAL BIAS CORRECTION METHOD FOR DAILY PRECIPITATION DATA OF GCM20

In this study, a simple statistical method is developed to correct bias in the precipitation simulated by GCM20, an atmospheric general circulation model with 20 km spatial resolution developed by the Meteorological Research Institute. The method primarily aims to correct intensity of GCM20 daily precipitation samples to express both seasonal patterns and extreme values appropriately. The basic idea of the bias correction is to adjust the probability distribution of GCM20 daily precipitation to that of its observed counterparts. To examine the correction performance the proposed method is applied to the Yoshino River basin in Japan. The results show that it appropriately corrects the GCM20 bias in both monthly and extreme daily precipitation.