The Water Vapor Transport Model at the Regional Boundary during the Meiyu Period

The water vapor transport model at the regional boundary in the Meiyu period is put forward throughdiagnostic analysis. The numerical simulation on the water vapor transport at the boundary of China inthe heavy rainfall period during June-July 1998 shows that the feature of water vapor transport in June isdifferent from that in July. The main body of the water cycle that forms the torrential rain in the Yangtze River Valley is made up of water vapor transport at the western and southern boundaries of the Chinaregion in June, whereas the water vapor flow at the western boundary in middle Tibet turns out to bethe main body of water vapor sources in July. The water vapor transport at the western boundary ofthe Tibetan Plateau and the southern boundary of China plays an important role in the torrential rainin the Yangtze River Valley. The temporal and spatial distribution characteristics of water vapor flow atthe regional boundary and their theoretical model would provide the scientific proof for the heavy rainforecasts in the Yangtze River Valley.