VERIFICATION ON STATIONARITY OF SUMMER PRECIPITATION BY USING HISTORICAL CLIMATE SIMULATION DATA OF d4PDF

Abstract

 This study aimed to verify the stationarity of historical and simulated precipitation data from the Database for Policy Decision-Making for Future Climate Change (d4PDF) by performing the nonparametric trend test. The test was conducted on summer precipitation data from seven locations in Japan. As a result of separately testing each ensemble member of d4PDF, it was found that the percentage with an increasing trend was significantly higher than the percentage with a decreasing trend. Results of testing all ensemble member together confirmed that the increasing trend was significant and thus also verified the nonstationarity of precipitation. After removing the trend from the combined d4PDF data, stationarity of the data was confirmed. 100-year precipitation data were calculated via the nonparametric method. As a result of comparing the observational data from the seven locations and the 100-year precipitation, we determined that 1-hour precipitation of d4PDF was underestimated.