The relationship between the high frequency areas of tropical cyclone in north-west Pacific and the circulation
Analyses of 41-yr (1965-2005) tropical cyclone (TC) activity over the western North Pacific (WNP)lead to a number of new findings on the climatological and interannual variation of the tropical cyclone activity and the relationship between the tropical cyclone activity and background circulation.We found two regions of high TC frequency (P region and S region) where their TC interannual variations are different.The P region is over the Philippine Sea and the corresponding index is index-p,shows about 10-year decadal variation and 1.8~4 years interannual variability.The index-s shows the frequency over the South China Sea,which display about 10-year decadal oscillation and 1.8~3 years interannual variability.In this paper,we talk about relationships between the TC activity in high frequency regions and the circulation on decadal time scale.On this scale we find that in P region,this relationship between them shows significant correlation coefficients in the Pacific.We find that P region as a high frequency region is mainly because it is the genesis of many TCs.The anomalous circulation shows warmer sea surface temperatures in the tropical central and eastern Pacific,lower sea level pressure,stronger low-level anomalous cyclonic vorticity and reduced vertical wind shear in P region when there are more TC in this region.All of these are favorable for TC to build up.It differs from P region,there are more TCs appearing in S region is because the tracks of many TCs pass this region.The relationship between them display that anomaly variability of the steering flow favor more cyclone comes trough the region.
Yuxing YANG Fei HUAGN
The Lab for Ocean-Atmosphere and Climate(OAC).Department of Marine Meteorology,Ocean University of C Department of Meteorology,and International Pacific Research Center,University of Hawaii at Manoa,Ho
国内会议
青岛
英文
108-118
2007-08-01（万方平台首次上网日期，不代表论文的发表时间）