平成30年7月豪雨の特性と地球温暖化

Abstract

The characteristics of the heavy rainfall event in July 2018 are long-lasting and widespread rainfall causing much total rainfall amount over Western Japan. We found a few hail in not so high clouds of this event compared with those of a typical back-building type heavy rainfall during Baiu season by analyzing the three-dimensional cloud information obtained from X-band multi-polarimetric Doppler radar. In terms of disasters, even though many hillslopes, river basins, and dam reservoirs have already almost reached the limits of patience by long-lasting rainfall till then, line-shaped rainfall have relentlessly passed again and again, and caused disasters and emergency discharges from dams as if hit continuously with a hammer. And for the impact assessment of global warming, it was not found the increasing trend in the frequency of atmospheric pattern of this heavy rainfall event in the future climate. On the other hand, the amount of water vapor inflow into Japan during the event was almost worst level in the present climate, moreover, it was extreme level even in the future climate.