Abnormal atmospheric circulation lead to Northeast of China's drought and flood climate directly, some specific circumferences merges with their mutual configuration are the significant conditions to form a severe and extensive drought or flood. Hence, it is quite important for us to deeply analysis and summarize those atmospheric circulate, so we can move forward in deepling the causes of our drought and flood climate, as well as taking precautions against disaster and reducing those disaster.
According to analysis of storm, the large scope rainfall is intimately related to interaction of Westerly systems, subtropical gyres and tropical circulation systems. In a certain large-scale circulation, it is easy to generate the cold and warm air for exchanging airflow, during this progress, mesoscale circulation background will be emerged and developed. Strong vapor and instability response energy can creat continued strong ascending motion, which offers conditions for large range storm. One of the circulation situation of rainstorm in northeast of China is that:
Typhoon type on west road
Typhoon landed in Zhejiang province, Fujian province or norther along coast to 30ºN. Northwest Pacific subtropical whose center lies in 130º~150ºE and 33º~40ºN, and whose ridge suits in 30º~40ºN had a high pressure into zonal distribution. The tropical convergence zone on the south side also included tropical vortex activity, and it can move north or northwest continuously.
In three days, not landing typhoon or those landfall typhoon with a depression low pressure would turn to the northeast of China, combining with westerly trough and forming regional heavy rain or local torrential rain. The three typhoon storms in early and middle August in 1985 belongs to this kind of reasons., which brought flood disaster for Liaohe River drainage.
The information is provided from Disaster Risk Reduction Knowledge Service.
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