越赤道气流准双周振荡对西北太平洋台风路径的调制作用  

The modulation of quasi-biweekly oscillation of cross-equatorial flow on typhoon tracks over the western North Pacific

作　　者：赵小平[1,2] 沈新勇[1] 王咏青[1] 朱文达[1] 张广鑫 

机构地区：[1]南京信息工程大学气象灾害省部共建教育部重点实验室,江苏南京210044 [2]西昌卫星发射中心气象室,四川西昌615000 [3]赣榆县气象局,江苏连云港221000

出　　处：《大气科学学报》2012年第5期603-619,共17页Transactions of Atmospheric Sciences

基　　金：国家重点基础研究发展计划973项目(2009CB421503;2011CB403405);国家自然科学基金资助项目(41075039;41175065);公益性行业科研专项(GYHY200806009);江苏省青蓝工程资助项目

摘　　要：利用美国联合台风预警中心(Joint Typhoon Warning Center,JTWC)热带气旋(tropical cyclone,TC)数据、NCEP/NCAR再分析风场资料,研究了越赤道气流准双周振荡对西北太平洋台风路径的调制作用。将西北太平洋台风路径划分为:西行路径、西北行路径、转向登陆中国路径、转向中日之间路径、转向登陆日本路径、转向日本以东路径和140°E以东路径。利用超前滞后回归方法,合成分析了6—10月不同路径台风对应的越赤道气流准双周振荡的低频环流演变过程。结果表明,925hPa越赤道气流及与其相联系的经向风存在明显10～20d准双周振荡现象,且对西北太平洋台风路径预报具有一定的指示作用。在西太平洋赤道地区,低频越赤道气流强度、演变特征影响着西北太平洋低频气旋的位置和移动方向,调节风场强辐合带与季风槽的位置与强度,继而对台风生成位置、移动路径产生重要的影响。初步认为,强向北低频越赤道气流分量有利于北侧低频气旋加强和向北传播,继而使得强辐合带、季风槽位置偏北,台风易于在此区域生成且沿着强辐合带位置移动,而弱向北低频分量或向南低频分量则不利于台风转向移动。This paper discusses the modulation effect of Quasi-biweekly oscillation of cross-equatorial flow on typhoon tracks over the Western North Pacific by using the tropical cyclones （TCs） data from the American Joint Typhoon Warning Center （JTWC） and NCEP/NCAR reanalysis wind data. The ty- phoon tracks are divided into seven types and the evolution of low-frequency circulation in the period of the atmospheric quasi-biweekly oscillation （QBWO） is synthetically analyzed through the methods of lead and lag regression. The results show that the meridional wind and cross-equatorial flow at 925 hPa bear the characteristics of periodic oscillations of 10 to 20 days and it is useful in forecasting the ty- phoon tracks over Northwest Pacific. In the equatorial region of North Pacific, the low-frequency crossequatorial flow and meridional wind can influence the low-frequency cyclone and anticyclone and mod- ulate the typhoon tracks by regulating the position and strength of intertropical convergence zone （ITCZ）. The component of the strong northward low-frequency cross-equatorial flow is beneficial for the low-frequency cyclone, and makes the ITCZ move northward. Typhoons can move along the zone of the ITCZ. The component of weak northward low-frequency flow or of southward low-frequency flow goes against the movement of typhoons.

关 键 词：越赤道气流 准双周振荡 台风路径 经向风 低频气旋 

分 类 号：P444[天文地球—大气科学及气象学]