影响福建热带气旋活动特征分析

CHARACTERISTICS OF FUJIAN-INFLUENING TROPICAL CYCLONES ACTIVITIES

分析了1960—2005年影响福建热带气旋(简称TC)的活动特征,结果表明:影响TC频数呈减少趋势;7—9月影响频数多,8月为最多;影响频次的空间分布呈东南-西北递减的带状分布;南海是影响TC生成频数最多的集中区域。分析了TC异常活动的环境场,在TC异常偏多年份,低层ITCZ位置偏北,西北太平洋(WNP)生成TC位置也较偏北,同时在中国东南沿海为异常的气旋性距平环流控制,非常有利于TC的生成和发展。对于低压环流影响年份,在WNP区域TC生成频数偏多偏北情况下影响中国东南沿海地区TC较频繁,则影响福建TC数偏多;反之,ITCZ明显偏弱,中国东南沿海为异常的反气旋性距平环流控制时,影响福建TC数偏少。对亚洲地区500 hPa大气环流分析发现,影响福建TC异常偏多(少)年份,副热带高压位置偏北(南)。

Characteristics of Fujian-influencing Tropical Cyclones（TCs） activities from 1960 to 2005 were analyzed in this paper.The results indicated that the TCs influening Fujian were more frequent in July-September,with the most in August.TC frequencies gradually decreased from the coastal region of southeast Fujian to the mainland of northwest Fujian.The primary source region of affecting typhoons was in the South China Sea.Analysing the interrelation between the WNP circulation abnormalies and TC activities,the authors discovered that in the years of positive anomalous frequencies of TC in Fujian,ITCZ was located more northward and TCs were generated more frequently.Cyclonic convergence circulation controlled Southeast China at low levels,which helped TCs to form and develop.In the years of low-pressure circulation,there were more TCs affecting the coastal area in Southeast China when more TCs formed and were located more northward in the WNP and then there were more TCs influening Fujian,and vice versa.Analysis of atmospheric circulation at 500 hPa over Asia showed that in the years of negative anomalous,the subtropical high was located more northward,and vice versa.