ROPOSAL OF THE CORRECTION FORMULA OF PROBABILITY RAINFALL PRODUCED BY 20-km d4PDF FOR GIFU PREFECTURE

Abstract

 This study proposes the simple correction formula of probability rainfall of 20-km d4PDF (database for Policy Decision making for Future climate change) for Gifu prefecture. Probability rainfalls by current climate simulation data of d4PDF and ground-based observation data by JMA are compared each by cumulative rainfall time. The relationships of the t-hour cumulative extreme rainfall of d4PDF and ground-based observation are proposed as follows: G1’_T =1.74 D1’_T, G168’_T =0.74 D168’_T., where, Dt’_T, and Gt’_T are T-year extreme probability t-hour cumulative rainfall of d4PDF and ground-based observation gage, respectively. RMSE for hourly rainfall is 18.1 mm, which is 22% of average value, and also RMSE for 168-hourly rainfall is 168mm, which is 30% of average value. The authors obtain the correction formula for short term rainfall with good accuracy and for long term rainfall with enough accuracy to predict landslide disaster.