抄録
Future changes in precipitation extremes and role of tropical cyclones are investigated by a large ensemble experiment, 6,000 years for the present and 5,400 years under +4 K warming, with a 60-km mesh atmospheric general circulation model (MRI-AGCM3.2). As in the previous findings by the authors, the annual maximum 1-day precipitation total (Rx1d) is projected to increase in the future warmer world almost all over the world, except in the western North Pacific where a projected decrease of tropical cyclone frequency results in only small change or even reduction of Rx1d. Furthermore, the large ensemble size enables us to investigate changes in the tails of the Rx1d distribution. It is found that 90- and 99-percentile values of Rx1d associated with tropical cyclones will increase in a region extending from Hawaii to the south of Japan. In this region, interannual variability of Rx1d associated with tropical cyclones is also projected to increase, implying an increasing risk of rare heavier rainfall events by global warming.
