Statistical Character Analyze of Tropical Cyclone During 1977-2008 in North Indian Ocean

doi:10.3969/j.issn.1673-7148.2011.03.002

Abstract：Adopting the tropical cyclone（TC） data during 1977-2008 in North Indian Ocean provided by JTWC,high-resolution blended data during 1982-2008 provided by NOAA,global reanalysis data during 1982-2008 provided by NCEP,the paper statistical analyzes 167 tropical cyclone cases in North Indian Ocean and the results show that： 1）The origin area of tropical cyclone was lie in the eastern of Arabian sea and middle of Bengal Bay.The tropical cyclones in Arabian sea was more frequent than that in Bengal Bay,the moved path of tropical cyclones in Arabian sea was often along with the western Ghats and moved toward northwest,landed over south of Pakistan,and the tropical cyclones in Bengal Bay usually landed over Bengal and the south of Burma.2）By using wavelet analysis,we found that the inter-annual variation of tropical cyclone in North Indian Ocean had the character of 2-4 years and 4-8 years significant cycle.3）Analyzed the intensity of the tropical cyclone and found out that there were 20 tropical cyclones meet the typhoon standard,3 tropical cyclones meet the severe typhoon standard,18 tropical cyclones meet the super typhoon standard.4）Obvious seasonal variation exhibited the form of high-low-high-low in spring,summer,autumn and winter;the spring and autumn were the high frequently season of tropical cyclone.The results of analyzing the stream field in 500 hPa show that the variation of convergence zone in 500 hPa stream field well explained seasonal changes of tropical cyclone.5）Sea surface temperature and monsoon impacted on occurrence frequency of tropical cyclone,high sea surface temperature and weak vertical wind shear were in favor of occurrence of tropical cyclone.