【作者】 赵小平；

【导师】 沈新勇；

【作者基本信息】 南京信息工程大学 ， 应用气象学， 2012， 硕士

【摘要】 根据美国联合台风预警中心(JTWC)热带气旋(TC)数据(1979-2010年)、NCEP/NCAR再分析风场及高度场格点资料,本文从气候学角度研究了近32年夏季(6-10月)热带地区大气准双周振荡(QBWO)对西北太平洋台风路径的影响。并在此基础上,利用风场资料,研究了越赤道气流准双周振荡特征对西北太平洋台风路径的调制作用。根据台风路径传统分类方法,本文将西北太平洋台风路径细分为：西行路径、西北行路径、转向登陆中国型路径、转向中日之间型路径、转向登陆日本型路径、转向日本以东型路径和140°E以东型路径。利用带通滤波、超前滞后回归等方法,合成分析了6-10月不同路径台风生成时刻的原始环流、低频环流、QBWO周期内低频环流演变过程以及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。通过分析大气准双周振荡特征对不同路径台风的影响,发现对流层低层至中层大气存在明显的10-20天准双周振荡特征,并且对西北太平洋台风路径预报有很好的指示作用。在西北太平洋地区,大气QBWO主要通过低频气旋和反气旋的分布、变化特征,影响南海季风槽、副热带高压的强度和位置,继而影响台风的生成位置与移动路径。菲律宾以东地区生成的热带低频气旋为南海季风槽的加强和台风的生成提供了有利的初始条件,低频气旋的正涡度带走向和移动趋势预示着台风未来的移动方向。分析发现,在副热带地区存在一支自西向东传播的大气QBWO波列。热带和副热带大气QBWO相互配合,共同作用,对西北太平洋台风路径产生重要影响。另外,对越赤道气流的准双周振荡特征分析发现,925hPa越赤道气流及与其相联系的径向风同样存在明显10-20天准双周振荡现象,且对西北太平洋台风路径预报有一定的指示作用。在西太平洋赤道地区,低频越赤道气流为南北半球能量、动量等输送提供有利条件,其强度、演变特征影响着西北太平洋低频气旋的位置和移动方向,调节赤道辐合带、副热带高压的位置与强度,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赤道辐合带位置偏北,易于台风转向北移,而弱向北低频分量或低频越赤道气流分量向南时则不利于台风转向。更多还原

【Abstract】 By using the Tropical cyclones(TCs) data from the American joint typhoon woring center (JTWC),reanalysis wind and height data by NCEP/NCAR, this paper discusses the modulation of typhoon tracks over the Western North Pacific by the atmospheric quasi-biweekly oscillation(QBWO) in the summer (June through october) for the nearly32years. In addition,by using of the wind data, This paper discusses the modulation of Quasi-biweekly oscillation of cross-equatorial flow on typhoon tracks over the Western North Pacific by using the Tropical cyclones (TCs) data and the wind data. We divide the typhoon tracks into seven types:straight west-moving typhoons, northwest-moving typhoons, typhoons recurving and landing in China, typhoons recurving to the regions between China and Japan, typhoons recurving and landing in Japan, typhoons recurving to the east of Japan and typhoons east of140°E. By the methods of band-pass filtering and the methods of lead and lag regression, this paper ananlyzes the original circulation, low-frequency circulation and the evolution of low-frequency circulation in the period of the atmospheric QBWO and the evolution of Low-frequency circulation of the cross-equatorial flow in925hPa. By analyzing the impact on the typhoons over the Western North Pacific of atmospheric quasi-biweekly oscillation, we find that the atmospheric have the characteristics of QBWO. The atmospheric QBWO influences the intensity and position of monsoon trough and subtropical high by the low-frequency cyclone and low-frequency anticyclone,thus influencing the formed location and movement of typhoon tracks. The low-frequency cyclone east of the Philippines will conducive to the formation of typhoons.The zone of positive vorticity of low-frequency cyclone will affect the movement of typhoon. In addition, the atmospheric QBWO eastward propagation in the subtropics also influences the typhoon tracks. The interaction of tropical and subtropical QBWO performs an important function on the typhoon tracks. Additionally, by analyzing the impact on the typhoons of the quasi-biweekly oscillation of cross-equatorial flow in925hPa, we find that the radial wind and cross-equatorial flow in925hPa have the characteristics of periodic oscillations of10to20days. In the equatorial region of Western North Pacific, the low-frequency cross-equatorial flow and radial wind provide advantageous conditions of energy and water vapor transport of Northern and Southern Hemisphere. The low-frequency cross-equatorial flow can influences the low-frequency cyclone and anticyclone and modulate the typhoon tracks by regulating the position and strength of ITCZ and subtropical high.更多还原