CHANGE OF PRECIPITATION AND RIVER DISCHARGE IN KYUSHU ISLAND BY GLOBAL WARMING BASED ON LARGE ENSEMBLE EXPERIMENTS

Abstract

 We analyzed the characteristics of changes in rainfall and river discharge due to global warming in four first-class river basins in Kyushu, focusing on the 48-hour annual maximum precipitation events in each year from the d4PDF past experiment and the 4°C rise experiment. It was found that the frequency of the summer season was higher in southern Kyushu than in northern Kyushu. Next, in addition to the increase in the frequency of major floods in all basins due to global warming, the peak number of hyetograph showed a decreasing trend in all basins, and the number of heavy rainfall events causing one- and two-peaks floods increased. This study indicates that global warming may cause not only an increasing precipitation, but also a decrease in the peak number of hyetograph, resulting in an increase in peak flood discharge.