Preliminary Study On The Rainfall And The Tracks Variation Of Landfalling Tropical Cyclone In East China

Typhoon is one of the most typical meteorological disasters in East China. Presently many achievements have been gained in area rainfall, but research on area TC precipitation was limited to nationwide and North China, and no according research was launched on East China, that was severely influenced by typhoon. Besides, no matter research or making long-range precipitation forecast, TC precipitation was not partitioned from total rainfall.First, the precipitation caused by typhoon "Rananin" partitioned by the Objective Synoptic Analysis Technique (OSAT) was compared with that by subjective analysis technique. Besides, we adjusted the parameters in the OSAT and contrasted the different results. Results show that, two outcomes are consistent. The OSTA is more objective and reasonable than subjective analysis technique in distinguishing precipitation from distant range TCs.Secondly, the landfalling tropical cyclone precipitation (TCP) is partitioned in East China by OSAT and its improvement programs. The climate characteristic of TCP was analyzed, and was compared with according characteristic of total rain in East China. The results show that, the spatial distribution of TCs rainfall is severely uneven in East China and the highest rainfall occurs in southeast Fujian Province with a decrease trend from southeast to northwest. This trend is consistent with terrain and other factors. The change of volume of TCP is evident with inter-annual and inter-decadal oscillations, with a decrease before the seventies. The inter-decadal decrease of TCP in East China happened 10 years earlier than that in North China. The climate characteristic of total precipitation is greatly different from that of TCP. Thus it makes sense to extract TCP from total precipitation before making long-time precipitation prediction.Last, the influenced areas and the distribution of strong wind and heavy rainfall are closely related with TC tracks after its landfalling. So the motion tracks of tropical cyclones (velocity is equal to or above 17.2m/s) landing at East China were statistically analyzed with best track data from 1945 to 2006, and we got some climatic rules. Results show that motion tracks of the landing typhoons is not only related to seasons, but also to landing positions.