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1.
路径突变是台风路径预报中的一个难题。2010年第10号台风Meranti（1010）在台湾岛南部海域西移过程中突然北折,而欧洲中期天气预报中心（ECMWF）集合预报对其北翘路径存在较大分歧。选取预报成功与不成功两组集合成员各8例,对比分析台风Meranti路径变化的主要原因。结果表明:（1）一个来自热带对流层上部槽的切断高空冷涡（UTCL）是该台风路径变化的一个重要影响系统。Meranti北翘路径跟它与UTCL的南北向耦合有关;（2）UTCL通过改变台风上层的环境气流影响台风引导气流。在UTCL移至台风北部过程中,台风的偏南风引导气流明显加强,有利于其路径北翘;（3）UTCL对台风Meranti北翘路径的影响还与其自身结构有关。水平环流宽且气旋性涡旋向下垂直伸展更深的UTCL对台风路径变化影响更明显;（4）位涡倾向方程的诊断分析表明,在TC与UTCL南北向耦合过程中,台风北部的正位涡水平平流项输送显著,有利于台风向北运动,且UTCL影响下产生的非对称风场在其中起主要作用。 相似文献
2.
局地海表温度异常影响热带气旋路径的模拟研究 总被引：6，自引：4，他引：2
本文以热带气旋"鲇鱼"(2010)为例,利用WRF模式和"鲇鱼"移动路径上不同的局地海表温度(SST)强迫进行了敏感性数值模拟。控制试验(CTRL)采用NCEP的SST强迫,敏感性试验分别在"鲇鱼"登陆菲律宾前的路径上增加(EXP1)和减小(EXP2)SST。结果表明:CTRL试验模拟的热带气旋路径与实况非常一致,EXP1试验模拟的热带气旋路径提前转向,移动路径偏东,EXP2试验模拟的热带气旋路径转向滞后,且移动路径偏西。对SST异常导致热带气旋路径出现差异的原因分析发现,热带气旋在吕宋岛东侧经过异常暖SST海面时,热带气旋强度增强,产生异常的正涡度平流,且500 h Pa以上凝结潜热释放增强副热带高压敏感区出现温度场的正异常,500h Pa以下水凝物的混合和蒸发作用增强造成副热带高压敏感区温度场的负异常,加之正的异常涡度平流和异常的上暖下冷温度场配置使得500 h Pa位势高度降低,副热带高压强度减弱,副热带高压西伸范围减小,导致热带气旋提前向北转向,移动路径偏东。反之,当热带气旋在吕宋岛东侧经过异常冷SST海面时,副热带高压西伸范围扩大,导致热带气旋向北转向滞后,路径偏西。 相似文献
3.
强台风Chanchu（0601）的数值研究：转向前后内核结构和强度变化 总被引：3，自引：0，他引：3
使用FY卫星TBB资料和新一代非静力中尺度模式WRF分析南海强台风Chanchu(0601)"急翘"转向前后内核结构和强度变化过程。结果表明:转向后内核结构非对称特征明显。WRF数值模式较好地模拟出Chanchu强度和异常路径变化过程,再现了内核结构演变:转向前,垂直切变较弱,有利于快速加强,内核结构较为对称;转向后,垂直切变明显增大,强回波位于垂直切变下风方向的左侧,显示为内核非对称结构。使用傅立叶变换方法分解模拟结果中的雷达回波,发现眼壁和内螺旋雨带的2波非对称沿方位角移速与涡旋罗斯贝波(VRWs)的理论波速一致,Chanchu快速加强过程中断和强度维持的可能原因为:眼壁传播的VRWs受到外螺旋雨带的扰动以及涡旋倾斜加剧引起眼壁非对称性加强导致"急翘"时眼壁破裂,此后眼区和眼壁区水平混合过程加强,850 hPa眼区相当位温明显增加,抑制高层相对暖干空气和低层相对冷湿空气相互交换,使得随眼壁内侧下沉气流向下输送的暖干空气减少,低层增温作用减弱,快速加强过程中断;VRWs径向内传导致高值涡度由眼壁内侧向眼心传播,引起最大风速半径(RMW)内侧切向风速增大,RMW随时间向眼心延伸,眼壁进一步收缩,一定程度上抵消了垂直切变加大的负面影响,Chanchu维持强度。 相似文献
4.
使用中国气象局热带气旋资料中心的热带气旋最佳路径数据集和NCEP/NCAR再分析资料提供的月平均数据,对北上影响山东的热带气旋（tropical cyclone,TC）及其造成的极端降水进行统计分析,并揭示了有利于 TC北移影响山东的大气环流特征。结果表明：影响山东的 TC主要出现 于 6—9 月,其中盛夏时节（7、8 月）TC对山东影响最大;TC影响山东时,强度主要为台风及以下等 级,或已发生变性;TC会引发山东极端降水事件,TC极端降水多出现在夏秋季（7—9 月）,其中8月的占比最大,9月次之,TC降水在极端降水事件中的占比约为 10%,但年际变化大,有些年份占比达60%以上,特别是1990 年以来 TC对极端降水的贡献显著增强;影响山东的 TC主要生成于西 北太平洋,多为转向型路径;当500 hPa位势高度异常场呈太平洋一日本遥相关型的正位相时,TC更易北上影响山东,此时西北太平洋副热带高压位置偏北,其外围气流会引导TC北上转向,对华东地区造成影响;850 hPa上,南海至西北太平洋存在异常气旋式环流,对流活跃,夏季风环流和季风槽加强,有利于TC的生成和发展,同时,华东、华南上空有异常上升运动,涡度增大,垂直风切变减小,水汽充沛,TC登陆后强度能得到较好的维持。 相似文献
5.
Yuxing Wang Yuan Sun Qianfeng Liao Zhong Zhong Yijia Hu Kefeng Liu 《Acta Meteorologica Sinica》2017,31(5):946-954
Typhoon Megi, the 13th typhoon of the 2010 typhoon season, was selected for case study by utilizing the Weather Research and Forecasting (WRF) model. Twelve sensitivity experiments with various initial tropical cyclone (TC) intensities and sizes were conducted to investigate their impacts on the simulation of typhoon track. Interaction between TC and the western Pacific subtropical high (WPSH) was also analyzed to explore the mechanism for the impact on TC track of the initial TC intensity and size. Numerical results indicate that the simulated TC size and TC track are sensitive to initial TC intensity and size. Stronger initial TC intensity and larger initial TC size often lead to larger simulated TC size and make TC turn northward earlier. Further analysis suggests that, with the increase of initial TC intensity and size, more air mass enters into the TC region, which subsequently reduces the extent of WPSH. As a result, the steering flow changes significantly and eventually causes the TC to turn northward earlier. The present study confirms that the initial TC intensity and size have certain influences on the TC track simulation, which demonstrates the importance of accurate initial condition for successful simulation of the TC intensity and TC track. Moreover, it also deepens our understanding of the interaction between TC and WPSH, provides helpful clues for the TC track change study, and discusses the future directions for improvement of TC track forecast. 相似文献
6.
西北太平洋热带气旋移动方向变化异常的环流特征 总被引：3，自引：2，他引：1
基于中国气象局和上海台风研究所整编的1972-2011年热带气旋(TC)best-track资料,采用极端天气气候事件定义的百分位法确定TC移动方向异常变化的阈值,利用Lanczos滤波法将大气环流分解成为季节内振荡(MJO)、准两周振荡(QBW)和天气3种尺度环流场,研究这3种尺度环流对热带气旋在南海地区异常北折的影响。结果表明:近40 a的资料统计显示,热带气旋12 h内移向逆时针方向偏转50°以及顺时针方向偏转47°为TC移动方向变化的95%分位数值,将12 h移动方向变化大于该数值的TC定义为移动方向变化异常。TC异常路径平均每年发生2.68次,9月份发生的概率最大,约为7%,最常发生在南海海域。分析3个发生在南海地区热带气旋异常北折的引导气流发现,在TC转向前,向西的引导气流纬向速度减慢,经向分量先向南加速,随后突然转为向北加速。天气尺度对应的引导气流对TC异常右偏影响最为明显,对流层中高层热带气旋中心东南侧强天气尺度西南气流引导TC异常右偏。 相似文献
7.
超强台风“天鹅”（2015）路径突变过程机理研究 总被引：2，自引：0，他引：2
本文采用中国气象局的最佳台风路径数据和美国国家环境预报中心1°×1°每6 h再分析资料作为研究工作的基本场,运用了分部位涡反演方法探讨影响2015年第15号超强台风“天鹅”路径突变的物理机制,得到以下结论:（1）就天气系统而言,“天鹅”整个移动过程中都受到周围环境场及引导气流的影响,主要的影响系统包括西北太平洋副热带高压、季风涡旋、邻近台风“艾莎尼”及台风外围反气旋;（2）定量分析了与各影响系统扰动位涡相关的引导气流矢量,发现整个过程中超强台风“天鹅”的移动始终受西北太平洋副热带高压的影响,其次是来自季风涡旋及台风外围反气旋的贡献,而当“天鹅”有向北转向趋势时,与外围反气旋相关的东北向引导气流导致了台风的路径北折;（3）进一步定量分析了总扰动位涡在不同高度层上相关引导气流的贡献,结果表明在垂直方向上对流层中层系统的引导气流矢量与“天鹅”的移动最为吻合,而形成于低层系统的偏南风气流与“天鹅”向北突然转向有着密切的联系,并在转向后逐渐向中高层发展增强。 相似文献
8.
Typhoon Chan-Hom(2015) underwent a weakening in the tropical western North Pacific(WNP) when it interacted with a monsoon gyre, but all operational forecasts failed to predict this intensity change. A recent observational study indicated that it resulted from its interaction with a monsoon gyre on the 15–30-day timescale. In this study, the results of two numerical experiments are presented to investigate the influence of the monsoon gyre on the intensity changes of Typhoon Chan-Hom(2015). The control experiment captures the main observed features of the weakening process of Chan-Hom(2015) during a sharp northward turn in the Philippine Sea, including the enlargement of the eye size, the development of strong convection on the eastern side of the monsoon gyre, and the corresponding strong outer inflow. The sensitivity experiment suggests that intensity changes of Chan-Hom(2015) were mainly associated with its interaction with the monsoon gyre. When Chan-Hom(2015) initially moved westward in the eastern part of the monsoon gyre, the monsoon gyre enhanced the inertial stability for the intensification of the typhoon. With its coalescence with the monsoon gyre, the development of the strong convection on the eastern side of the monsoon gyre prevented moisture and mass entering the inner core of Chan-Hom(2015), resulting in the collapse of the eyewall. Thus, the weakening happened in the deep tropical WNP region. The numerical simulations confirm the important effects of the interaction between tropical cyclones and monsoon gyres on tropical cyclone intensity. 相似文献
9.
In this study,the effect of vertical wind shear(VWS)on the intensification of tropical cyclone(TC)is investigated via the numerical simulations.Results indicate that weak shear tends to facilitate the development of TC while strong shear appears to inhibit the intensification of TC.As the VWS is imposed on the TC,the vortex of the cyclone tends to tilt vertically and significantly in the upper troposphere.Consequently,the upward motion is considerably enhanced in the downshear side of the storm center and correspondingly,the low-to mid-level potential temperature decreases under the effect of adiabatic cooling,which leads to the increase of the low-to mid-level static instability and relative humidity and then facilitates the burst of convection.In the case of weak shear,the vertical tilting of the vortex is weak and the increase of ascent,static instability and relative humidity occur in the area close to the TC center.Therefore,active convection happens in the TC center region and facilitates the enhancement of vorticity in the inner core region and then the intensification of TC.In contrast,due to strong VWS,the increase of the ascent,static instability and relative humidity induced by the vertical tilting mainly appear in the outer region of TC in the case with stronger shear,and the convection in the inner-core area of TC is rather weak and convective activity mainly happens in the outer-region of the TC.Therefore,the development of a warm core is inhibited and then the intensification of TC is delayed.Different from previous numerical results obtained by imposing VWS suddenly to a strong TC,the simulation performed in this work shows that,even when the VWS is as strong as 12 m s-1,the tropical storm can still experience rapid intensification and finally develop into a strong tropical cyclone after a relatively long period of adjustment.It is found that the convection plays an important role in the adjusting period.On one hand,the convection leads to the horizontal convergence of the low-level vorticity flux and therefore leads to the enhancement of the low-level vorticity in the inner-core area of the cyclone.On the other hand,the active ascent accompanying the convection tends to transport the low-level vorticity to the middle levels.The enhanced vorticity in the lower to middle troposphere strengths the interaction between the low-and mid-level cyclonical circulation and the upper-level circulation deviated from the storm center under the effect of VWS.As a result,the vertical tilting of the vortex is considerably decreased,and then the cyclone starts to develop rapidly. 相似文献
10.
A study on the impact of asymmetric components around tropical cyclone center on the accuracy of bogus data and the track forecast 总被引：6，自引：0，他引：6
M. Ueno 《Meteorology and Atmospheric Physics》1995,56(1-2):125-134
Summary The Japan Meteorological Agency (JMA) has used a tropical cyclone bogus insertion procedure to produce correctlypositioned, cyclone-like vortices within the initial analyses and to track the vortices throughout the model forecasts. The TC bogus soundings are constructed from a standard axisymmetric vortices for well developed tropical cyclones based on a few manually-analyzed parameters such as storm position, central pressure and radius of gale force wind. Mainly because of such an axi-symmetric property of JMA TC bogus data, which is likely to remove the steering flow from the central core region of TC, all the JMA models have a noticeable slow-start bias error and also northward drifting blas error in TC movement. In order to investigate the impact of asymmetric wind components on the TC track forecast, an experimental analysis-forecast cycle is conducted using the JMA global spectral model, in which asymmetric components extracted from the first guess fields are added to the axisymmetric TC bogus. It is found from the experiment that both the slow-start bias error and northward bias error can be reduced by introducing the asymmetric components into the TC bogus. Besides the impact study, a statistical verification study of the bogus data was also made against real data such as sonde data and superiority of the preparation method of asymmetric components was proved.With 9 Figures 相似文献
11.
利用中国气象局(CMA)提供的热带气旋最佳路径资料和欧洲中心(ECMWF)提供的ERA interim再分析资料,对2018年两个北上影响山东的台风"摩羯"和"温比亚"路径差异的原因进行分析发现:"摩羯"和"温比亚"台风路径的差异主要与周围天气系统分布差异有关,两台风均先后受到副热带高压和大陆高压的影响,"温比亚"还受高空槽的影响,使其转向角度较大,而台风与高压系统相互作用形成的引导气流是影响这两个台风路径的主要因素。"摩羯"和"温比亚"的最佳引导气流均位于台风中心5个纬度半径内,不同阶段所受引导气流的高度存在差异,台风登陆前中低层引导气流对台风移向的指示作用均优于高层,登陆后转向前纬向引导气流均优于经向,但稳定性稍差,转向后除"温比亚"经向引导气流相关较差外均整层相关较好,中高层略优于低层,且高层风(300～200hPa)可以提前12h预报台风转向。此外,台风总是向着台风附近的正涡度平流方向移动,正涡度平流越强,台风移动越快。 相似文献
12.
基于气候系统模式FGOALS-g2的热带气旋活动及其影响的动力降尺度模拟 总被引：2，自引：2，他引：0
热带气旋是气候模拟关注的重要对象,但是,由于当前的气候系统模式分辨率较低,难以合理再现热带气旋分布特征,因此,动力降尺度就成为一种有效的手段。本文使用区域气候模式RegCM3,对中国科学院大气物理研究所气候系统模式FGOALS-g2的模拟结果进行动力降尺度,基于热带气旋路径追踪法,从热带气旋的路径、强度和降水三个方面,检验了动力降尺度在热带气旋模拟能力上的增值。结果表明,动力降尺度结果大幅提升了热带气旋路径频率的模拟,较之全球模式,其与观测的路径频率分布的空间相关系数从0.57提升至0.74;区域模式模拟的热带气旋强度与观测更为一致,全球模式难以模拟40 m s?1以上风速的热带气旋,区域模式能够模拟风速为60 m s?1的热带气旋;在热带气旋降水方面,降尺度后的热带气旋降水贡献率和平均热带气旋降水强度均有所改善,在西北太平洋区域较之全球模式,区域模式将热带气旋降水贡献率和降水强度提高了10%和4.7 mm d?1。动力降尺度后TC（tropical cyclone）的模拟技巧得到提升的区域为西北太平洋区域,但在中国南海区域,技巧提升的不显著甚至有所下降。关于动力降尺度结果在西北太平洋区域的技巧提升,分析表明能够更好体现CISK（Conditional Instability of the Second Kind）机制是主要原因,区域模式模拟的水汽增多、正涡度增强、上升运动增强而垂直风切变减弱都有显著贡献。 相似文献
13.
Considering the feature of tropical cyclones (TCs) that strong positive vorticity exists in the lower layers of troposphere, this study proposed to use vorticity at 850 hPa as cost function to find the conditional nonlinear optimal perturbation (CNOP), which was largely different from those previous studies using total energy of perturbed forecast variables. The CNOP was obtained by an ensemble-based approach. All of the sensitive areas determined by CNOP with vorticity at 850 hPa as cost function for the three cases were located over the TC core region and its vicinity. The impact of the CNOP-based adaptive observations on TC forecasts was evaluated with three cases via observational system simulation experiments (OSSEs). Results showed obvious improvements in TC intensity or track forecasts due to the CNOP-based adaptive observations, which were related to the main error source of the verification area, i.e., intensity error or location error. 相似文献
14.
随机分布的小尺度涡旋场对台风路径影响的研究 总被引：2，自引：1，他引：1
文中用正压原始方程模式和理想初始场研究了随机分布的小尺度涡度场对台风路径的作用.在模式初始场上,有一个理想的副热带高压脊、一个台风和一个随机生成的小尺度涡度场.设计实施两组试验,记为试验A和试验B,积分时间为56 h.每个试验的初始场上各有100个随机分布的小尺度涡.除了小尺度涡的空间位置不同以外,两组试验其余的试验条件全部相同.模式积分的结果指出:小尺度涡不同的空间分布可以引起台风外围水平风速的差异,进而改变台风环境引导流的强度.在24、36和48小时,试验A沿东西方向环境引导流分别为7.8、8.2和8.7 m/s,24-48小时平均值为8.2 m/s,沿南北方向环境引导流分别为0.9、1.8和2.5 m/s,24-48小时平均值为2.1 m/s;试验B沿东西方向分别为8.3、9.5和9.7 m/s,24-48小时平均值为9.5 m/s,沿南北方向分别为2.3、2.3和5.9 m/s,24-48小时平均值为3.4 m/s.环境引导气流强度的小同导致未来台风中心位置的不同.两组不同的初始随机涡度场可以引起48 h以后台风中心相距约120 km.副热带高压与台风相互作用的动力学表明:当初始台风位于副热带高压脊与赤道之间时,局域的绝对涡度梯度与台风传播的关系足南若干个不规则的散布点表征的.引进随机涡度场以后,副热带高压脊、台风和小尺度涡旋三者的共同作用使得绝对涡度梯度与台风传播之间的关系复杂化,除了会出现不规则散布点的特征外,还可显示出两者之间的高相关特征. 相似文献
15.
利用1979—2012年西北太平洋热带气旋最佳路径资料,Hadley中心的海温资料和NCEP/NCAR再分析资料等,研究了夏季(6—10月)热带北大西洋海温异常与西北太平洋热带气旋(Tropical Cyclone,TC)生成的关系及其可能机制。结果表明,夏季热带北大西洋海温异常与同期西北太平洋TC生成频次之间存在显著的负相关关系。热带北大西洋海温的异常增暖可产生一对东—西向分布的偶极型低层异常环流,其中气旋性异常环流位于北大西洋/东太平洋地区,反气旋异常环流位于西北太平洋地区。该反气旋环流异常使得TC主要生成区的对流活动受到抑制、低层涡度正异常、中低层相对湿度负异常、中层下沉气流异常,这些动力/热力条件均不利于TC生成。此外,西北太平洋地区低层涡旋动能负异常,同时来自大尺度环流的涡旋动能的正压转换也受到抑制,不能为TC的生成和发展提供额外能量源。反之亦然。 相似文献
16.
两类El Niño型对西北太平洋季风槽及热带气旋生成的可能影响 总被引：1，自引：0，他引：1
通过对1948~2015年不同El Ni?o事件下西北太平洋季风槽变化和热带气旋(tropical cyclone,TC)生成进行分析,初步探讨了不同El Ni?o型事件对季风槽及其对TC的可能影响。分析结果表明,较东太平洋增暖(eastern Pacific warming,EPW)年,中太平洋增暖(central Pacific warming,CPW)年季风槽偏弱,位置相对偏西、偏北。在CPW年,中(西和东)太平洋海温增暖(降低)引起了从中到西太平洋热带地区的西风异常和中太平洋地区上升运动及对流活动加强,使得季风槽加强东伸,同时西太平洋副高偏弱、偏北,季风槽向北推进;而在EPW年,赤道东(西)太平洋海温增暖(降低)使得赤道地区西风异常显著加强东扩,异常Walker环流的上升支东移至东太平洋,季风活动加强,副高偏强、偏南,这使得季风槽较CPW年相比更强、更偏东。利于TC生成的大尺度环境因子随季风槽强度和位置的变化而发生改变,在CPW年,低层气旋性涡度、高层辐散、高的中层相对湿度以及低垂直风切变区随着季风槽向北移动;而在EPW年,这些因子随季风槽向南、向东偏移。这些大尺度环境因子的变化使得西北太平洋TC生成的位置在CPW年比EPW年更加偏北、偏西。 相似文献
17.
利用中国气象局上海台风研究所（CMA/STI）整编的热带气旋最佳路径资料、美国飓风联合警报中心（JTWC）最佳路径资料、美国国家海洋与大气管理局（NOAA）的全球多平台热带气旋风场资料（MTCSWA）和CMORPH降水资料、日本卫星云顶黑体辐射温度（TBB）资料等,分析1987～2016年30年间西北太平洋228个变性热带气旋（ETTC）的活动规律、风与降水分布及其演变特征。结果表明:（1）ETTC年均7.6个,除1～2月,各月均有分布,峰值在9月。约90.4%的ETTC变性位置在30°N以北,仅约9.6%在30°N以南较低纬度,且多发生于春夏和秋冬交替季节。（2）TC（热带气旋）变性通常发生在其转向后,半数以上移速加快,大多数中心气压升高或维持,仅10.5%降低。（3）变性过程中ETTC近中心最大风速减小,最大风速半径增大,内核趋于松散。其34节风圈半径北侧明显大于南侧,风场结构非对称性增强。（4）ETTC强风和强降水呈显著非对称性分布,其强风区主要出现在ETTC中心东侧,即路径右后方;强降水区主要出现在北侧,且变性后在东北象限向外扩张。（5）较强的环境水平风垂直切变（VWS）是影响ETTC风及降水分布的重要因子。强降水主要出现在顺风切方向及其左侧,强风（去除TC移速时）出现在切变左侧。 相似文献
18.
Super Typhoon Mangkhut (2018) was the most high-impact typhoon in 2018 because of its long lifespan and significant intensity. The operational track forecasts in the short-to-medium range (deterministic and probabilistic forecast) showed a great uncertainty and the forecast landing points varied with different lead times. This study applied ensembles of high-resolution ECMWF forecasts to investigate the major factors and mechanisms of the bias production of the Mangkhut forecast track. The ensembles with the largest track bias were analyzed to examine the possible bias associated factors. The results suggested that environmental steering flows were the main cause for the erroneous southward track error with a variance contribution of 72%. The tropical cyclone (TC) size difference and the interaction of the TC with the subtropical high (SH) were other two key factors that contributed to the track error. Particularly, larger TCs may have led to a stronger erosion of the southern part of the SH, and thus induced significant changes in the large-scale environment and eventually resulted in an additional northward movement of TC.
相似文献19.
Super Typhoon Mangkhut(2018)was the most high-impact typhoon in 2018 because of its long lifespan and significant intensity.The operational track forecasts in the short-to-medium range(deterministic and probabilistic forecast)showed a great uncertainty and the forecast landing points varied with different lead times.This study applied ensembles of high-resolution ECMWF forecasts to investigate the major factors and mechanisms of the bias production of the Mangkhut forecast track.The ensembles with the largest track bias were analyzed to examine the possible bias associated factors.The results suggested that environmental steering flows were the main cause for the erroneous southward track error with a variance contribution of 72%.The tropical cyclone(TC)size difference and the interaction of the TC with the subtropical high(SH)were other two key factors that contributed to the track error.Particularly,larger TCs may have led to a stronger erosion of the southern part of the SH,and thus induced significant changes in the large-scale environment and eventually resulted in an additional northward movement of TC. 相似文献
20.
Simulated impacts of two types of ENSO events on tropical cyclone activity in the western North Pacific: large-scale atmospheric response 总被引：1，自引：0，他引：1
The present paper uses an atmospheric general circulation model to explore large-scale atmospheric response to various El Niño-Southern Oscillation events associated with tropical cyclone (TC) activity in the western North Pacific. The simulated response is basically consistent with and confirms the observed results. For eastern Pacific warm (EPW) event, anomalously wet ascent occurs over the tropical central/eastern Pacific and dry descent is over the western Pacific. This Walker circulation is associated with anomalous low-level convergence, reduced vertical wind shear (VWS), and enhanced genesis potential index (GPI) in the southeast sub-region. These are consistent with the observed increase of the TC formation in the southeast sub-region but decrease in the northwest sub-region during July–September (JAS) and the increase in the southwest and northwest sub-regions during October–December (OND). In addition, the strong westerly anomalies of the TC steering flow prevail in the East Asian coast, suppressing the TC northwestward or westward tracks. For eastern Pacific cold (EPC) event, all of the simulated variables show almost a mirror image of EPW. For central Pacific warm event, the anomalous Walker circulation shifts westward because of the westward shift of the maximum SST anomaly forcing. The anomalous subsidence associated with the western branch of the Walker circulation during OND shifts northward to the South China Seas, resulting in a decrease of the TC genesis there. The TC steering flow patterns during JAS are favorable for TCs to make landfall over Japan and Korea. Compared with EPC, the descending motion in the central/eastern Pacific is much stronger for central Pacific cold (CPC) event, accompanied by more enhanced VWS and reduced GPI in the southeast sub-region. Therefore, CPC provides a more adverse environment to the TC formation there during JAS and OND, consistent with the observed decrease of TC formation there. Moreover, the easterly anomalies of the TC steering flow dominate the tropics during JAS, enhancing TC activity in the east coast of China. Additionally, the convection over the western Pacific moves to the South China Sea during OND, favoring the TC genesis there. 相似文献