2005年夏季中国登陆台风的环流特征  

The Circulation Characteristics of Frequent Activities of Typhoons over Eastern China during the Summer of 2005

作　　者：刘舸[1] 张庆云[1] 孙淑清[1] 

机构地区：[1]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室

出　　处：《大气科学》2007年第5期909-918,共10页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展规划项目2004CB418303;中国科学院知识创新工程重要方向项目KZCX3-SW-221;国家自然科学基金资助项目40523001

摘　　要：利用NCEP/NCAR再分析资料和中国台风网提供的2005年台风资料,研究了2005年夏季台风登陆及中国东部频发性台风暴雨的环流特征及南北半球环流系统的相互作用。2005年夏季登陆我国的台风存在显著的阶段性变化,即6月10日~7月11日西太平洋无热带气旋生成,7月12日~9月30日西太平洋热带气旋频繁活动,造成登陆我国台风间隔时间短、频数高、强度强,使得我国东部台风暴雨频繁发生。研究指出,6月10日~7月11日西太平洋无热带气旋生成与西太平洋副热带高压位置偏南、越赤道气流较弱、东亚热带辐合带(5°N^15°N,120°E^150°E)对流偏弱有关。而在7月12日~9月30日,西太平洋热带气旋活动频繁与西风槽的多次南下、西太平洋副热带高压断裂(或东撤)、东亚热带辐合带对流加强有关。进一步研究发现,气候平均态的西太平洋越赤道气流分别位于125°E和145°E附近,2005年夏季125°E和145°E附近的越赤道气流减弱,然而在7月12日~9月30日,130°E^135°E附近的越赤道气流加强并维持时间较长。130°E^135°E附近越赤道气流加强与澳大利亚高压东移以及140°E^180°E赤道低压加深有关。Landing typhoons exert important influence on the rainfall over eastern China. Several intense rainfalls over eastern China are caused by landing typhoons in 2005, moreover they are frequent after the middle of July. The activity of tropical cyclones （TCs） over the western North Pacific in 2005 has its own features. The frequency of tropical cyclogenesis in 2005 is a little less than the mean frequency （1951 - 2000）. However, the intensity of tropi- cal cyclone is stronger, and the percentage of the frequency of landing typhoons to the frequency of cyclogenesis is greater. These frequent landing typhoons result in intense rainfalls over eastern China. The activity of tropical cyclones can be divided into two phases., the first phase, less TC phase （10 June - 11 July） and the second phase, more TC phase （12 July- 30 September）. To explain the above phenomenon, the climatological feature of rainfall caused by landing typhoon is studied, and the relationship between tropical cyclone activity and north （south） hemispherical low latitude circulations is primarily researched in this paper. The results show that, in the less TC phase, the western Pacific subtropical high was more southern than normal, and it restrained the cross-equatorial flow. The convection over the inter-tropical convergence zone （ITCZ） （5°N- 15°N, 120°E- 150°E） was weaker. Thus no TC originated in this phase. In the more TC phase （12 July- 30 September）, the waves of westerly were frequent, the influence of trough of westerly wind was more southern than normal, the convection over the ITCZ was stronger, and the western Pacific subtropical high moved north and east accompanied by several breaks in the same phase. In brief, there were more TCs in this phase because of the influence of westerly trough, subtropical high and ITCZ. The reason why the above circulations occur in the more TC phase is studied. It is found that, there are two crossequatorial flows in climatological average years, which are located near 125

关 键 词：热带气旋 赤道辐合带 越赤道气流 澳大利亚高压 赤道低压 

分 类 号：P444[天文地球—大气科学及气象学]