Abstract
In Japan, flooding damages by rainfall are increasing in recent years, because Japanese river is located steep hillslopes and severe rainfall is increasing. Therefore, it is of great importance to improve the long-term forecast of rainfall for reservoir efficient operation. In this study, we research the verification accuracy of ensemble forecast of precipitation provided by Japan Meteorological Agency at a basin of Tenryu River. And we research a technique of extreme event forecast using the probability distribution of ensemble forecast. As a result, one month ensemble rainfall forecast underestimate heavy rain, and overestimate weak rain, but we can compensate this underestimation and overestimation by using probability distribution. And we can forecast heavy rain using extreme event forecast.
