抄録
Mesoscale convective systems (MCSs) that bring rainfall in the vicinity of Kyushu Island, Japan during the late Baiu season in the present and global warming climates are examined by a non-hydrostatic regional climate model (NHM) with the horizontal grid of 5 km.
In the global warming climate, two types of MCSs appear in the vicinity of Kyushu Island. One travels from the Chinese Continent and the other from the southern part of the East China Sea to Kyushu Island. These two MCSs often merge over the sea southwest of Kyushu Island, and they rapidly develop to bring heavy precipitation to the vicinity of Kyushu Island. Among the latter, MCSs with low cloud-tops below 4 km MSL (Mean Sea Level) are found.
In the comparison with the present climate, the averaged cloud and rain water mixing ratios in the vicinity of Kyushu Island become much larger, and the peak altitude of the mixing ratios are about 0.5-1.0 km higher in the global warming climate. The cloud water mixing ratio between 2-4 km MSL increases in the global warming climate, corresponding to MCSs with low cloud-tops.
These results suggest one of the processes to produce heavy rainfall in the vicinity of Kyushu Island in July in the global warming climate.
