Study On Climatic Characteristics Of Jiang-Huai Cyclone

By using the historical weather charts during the period of1961to2009from the Central Meteorological Observatory. The track, origin, frequency, intensity of Jiang-huai cyclone were collected. The results showed that there were declining trend in decadal variations on frequency of cyclone and rising trend in generated intensity of cyclone. Moreover, the frequency of Jiang-huai cyclone had apparent inter-annual and decadal variations periodic characteristics by the analysis of wavelet. It was obviously different from months and seasons. In particular, April and spring were the periods that the Jiang-huais cyclone most favorably occurred. Influenced by topography、 underlying surface and other factors, the Jiang-huai cyclones occurred in three regions:near Dabie Mountains and northeast of it、upper reaches of Huaihe and Jiangsu、Anhui and Zhejiang junction; There were mainly three paths: from Northwest Road、North Road、South Road to eastward. and the moving paths of cyclone had significant seasonal changes and month changes.Based on the historical weather charts from the Central Meteorological Observatory and using the ways of EOF and probability density, the relationship between the height and frequency of Jiang-huai cyclones were discussed. In addition, two-dimensional probability density (PDF) was analyzed from principal component coefficients that derived from decomposition of EOF according to the daily high field data. The results showed that time-Varying trend on Jiang-huai cyclones were associated with two regimes named the A regime and B regime. The B regime was associated with the frequency of Jiang-huai cyclones generated in spring and summer, and the A regime with the comparatively autumn and winter.Monthly、seasonal and decadal variations of Jiang-huai cyclones are closely related to environmental field.In spring, the correlation analysis shows that there is a negative correlation between the occurrence of Jiang-huai cyclones and the Asian Continental cold high, as well as a positive correlation between the occurrence of Jiang-huai cyclones and the Western Pacific Subtropical High. Moreover, there is absolutely different between the four typical years of the most and least Jiang-huai cyclones. The intensity of Asian Continental cold high and trough of east Asia in the most years of Jiang-huai cyclones are stronger than corresponding one. There is a low sea temperature in the most years of Jiang-huai cyclones in Jiang-huai.river basin; There is a high sea temperature in the least years of Jiang-huai cyclones in Jiang-huai river basin.Resrarching on the typical case of Jiang-huai cyclones,it shows that Jiang-huai cyclones generate in the unstable atmosphere,and often accompanied with the strong winds and precipitation process, moreover, Jiang-huai cyclones is the the weather system that have the frontal structre.