A STUDY OF RAPID DECAY TYPHOONS IN OFFSHORE WATERS OF CHINA     

郑峰  曾智华  雷小途  陈联寿  杨涛  朱景 《热带气象学报(英文版)》2017,23(4):471-480

On the basis of NCEP/NCAR reanalysis data and yearbooks of CMA tropical cyclones, statistical analysis is performed for 1949—2013 offshore typhoons subjected to rapid decay(RD). This analysis indicates that RD typhoons are small-probability events, making up about 2.2% of the total offshore typhoons during this period. The RD events experience a decadal variation, mostly in the 1960 s and 1970 s(maximal in the 1970 s), rapidly decrease in the 1980 s and 1990 s and quickly increase from 2000. Also, RD typhoons show remarkable seasonal differences: they arise mainly in April and July-December, with the prime stage being in October-November. The offshore RD typhoons occur mostly in the South China Sea(SCS) and to a lesser extent in the East China Sea(ECS); however, none are observed over the Huang Sea and Bo Sea.Composite analysis and dynamic diagnosis of the RD typhoon-related large-scale circulations are performed.Physical quantities of the composite analysis consist of 500-h Pa height and temperature fields, vapor transfer, vertical wind shear(VWS), density of core convection(DCC), and high-level jet and upper-air outflow of the typhoon. The results suggest that(1) at the 500-h Pa height field, the typhoon is ahead of a westerly trough and under the effects of its passing trough;(2) at the temperature field, the typhoon is ahead of a temperature trough, with an invading cold tongue present;(3) at the vapor transfer field, water transfer into the RD typhoon is cut off; and(4) at higher levels, the related jet weakens and the outbreak of convection becomes attenuated in the typhoon core. In addition, VWS bears a relation to the RD typhoon; in particular, strong VWS favors RD occurrence.The differences in RD events between the SCS and ECS show that for the RD, the VWS of the ECS environmental winds is markedly stronger in comparison with its SCS counterpart. The cold advection invading into the typhoons is more intense in the SCS than in the ECS, and the low-level vapor transfer and high-level outflow are weaker in the SCS RD typhoons.Data analysis shows that sea surface temperature(SST), VWS, and DCC can be employed as efficient factors to predict RD occurrence. With appropriate SST, VWS, and DCC, a warning of RD occurrence can be given 36, 30-36,and 30 h, respectively, in advance. These values suggest that atmospheric SST responses lag. Owing to this time lag,the prediction of RD typhoons is possible.  相似文献   

非绝热加热对热带气旋径向非均匀结构的影响   总被引：14，自引：2，他引：12  

雷小途 《海洋学报》2000,22(4):24-30

利用平面极坐标系下无摩擦有外源(非绝热加热)的正压无辐散方程,将热带气旋的物理量分解成环境场和扰动,进而求出了热带气旋扰动的行波解,并分析了风场(切向、径向)和重力位势扰动场的径向非均匀松紧结构.表明:这种松紧结构与热带气旋所在纬度的科氏参数(f)、热带气旋的强度(Ω)、热带气旋扰动的圆频率(ω)、热带气旋扰动在θ方向的角波数(m)有关,且不同要素的松紧结构不尽相同;同时还受非绝热加热(Q₁)的影响,这种影响主要表现在使风场(切向、径向)呈内紧外松的非均匀分布.  相似文献   

DYNAMIC ANALYSIS OF INHERENT CAUSES FOR DEVIATION OF TROPICAL CYCLONE TRACKS     

雷小途 《热带气象学报(英文版)》2001,7(1):53-62

To have a clearer picture of mechanisms responsible for the deviation of tropical cyclone (to be simplified as TC hereafter) tracks, the current work assumes the TC as a circular vortex with a radius of R. A general motion equation of TC is then determined by averaging its horizontal motion equation over the sentire region of TC. In the meantime, with the moving track of TC assumed as a characteristic arc, the curvature equation is derived for the track of movement and patterns of its deviation due to TC structure and variation are discussed. The result shows that the scale, size, maximum wind speed and radius are factors causing the deviation of TC tracks. In addition, asymmetric structure of TC is also important for the deviation of tracks. The results, achieved with hypothesis, agree with facts in some cases but disagree with them in others, which are to be verified with more observations or numerical simulations.  相似文献   

西北太平洋热带气旋最佳定位的精度分析   总被引：11，自引：3，他引：11  

雷小途 《热带气象学报》2001,17(1):65-70

用正交小波变换方法分析了近121年来季节的南方涛动指数与北大西洋涛动指数的演变特征，结果表明南方涛动指数（SOI）最显著的变化是周期约为2－7年的年际变化，它们的方差贡献率为55．1％。1920年以前和1960年以后SO年际及年代际变化较强，其余时段较弱。而NAOI最明显的变化是周期在2年以下的变化，方差贡献率为64．3％。近百年NAOI年际及年代际变化有减弱趋势。近百年来SOI有－0．52／百年的减小趋势，而NAOI有0．25／百年的增大趋势。SOI与NAOI的气候基本态之间有显著的负相关，在年代际和年尺度变化上它们相关不明显。近期北半球处于SOI低基本态高年际及年代际变率，NAOI高基本态低年际及年代际变率的慢变过程下。  相似文献   

Winnie(1997)和Bilis(2000)变性过程的湿位涡分析   总被引：29，自引：8，他引：29       下载免费PDF全文

李英  陈联寿  雷小途 《热带气象学报》2005,21(2):142-152

9711号台风Winnie和0010号台风Bills均在中国大陆发生变性，但前者变性后再度加强，而后者变性后减弱消亡。从湿位涡理论出发，对比分析两者的变性过程，结果表明：作为变性台风，Winnie和Bilis均在北上过程中与中纬度西风槽发生作用，但前者与高空槽发生耦合，后者仅接近高空槽底部，没有发生耦合；Winnie变性加强过程表现为一个温带气旋在低层锋区上的强烈发展过程，主要与高层正位涡扰动下传、低层锋区及热带气旋低压环流之间的相互作用有关。Pm湿斜压项增长引起的倾斜涡度发展是登陆热带气旋变性加强的主要因子。在Bills变性过程中，高层无明显的正位涡扰动下传，热带气旋低压环流内无锋区面出现，大气斜压性弱且变化不明显。  相似文献   

CHARACTERISTICS OF TROPICAL CYCLONES ACTIVITIES VARYING WITH ENVIRONMENTAL FIELDS OF MID- AND LOWER- LATITUDES     

雷小途  陈联寿 《热带气象学报(英文版)》2003,9(1):19-30

1INTRODUCTIONTropicalcyclones(tobedesignatedTChereafter)actwithsignificantlatitudinaldifference[1],someofwhichhavebeenwelldocumented.Forinstance,TCisavortexsystemthatformsandmaintainswiththesupportofsomeextentofCoriolisforce,whichisweakinareasneartheequator(southof4N)andenableslittleTCactivity[2].AsTCismainlysuppliedbylatentheating,higherSSTissuretobeadvantageoustothegenerationanddevelopmentofTC;thesummertimeSSTdecreaseswithincreasinglatitudeinthenorthwesternPacific[3],beingnear26.…  相似文献   

西北太平洋热带气旋变性的客观判据研究     

郭蓉  雷小途  汤杰 《热带气象学报》2018,34(3):353-359

用体现热带气旋（TC）热力学特征的“相空间”（简称CPS）方法,加入了体现TC动力学特征的两个参数,即中低层风速切变参数和涡倾斜参数,对2000—2007年的222个TC进行检验。结果表明,CPS方法在增加了动力学参数后,可以更好地描述西北太平洋地区的TC变性过程,弥补了CPS方法对TC动力学特征描述的欠缺,同时客观判据的判断结果与《热带气旋年鉴》资料更相近。   相似文献   

EFFECTS OF SST, VWS, AND DCC UPON RAPID INTENSIFICATION OF OFF-SHORE TYPHOONS IN CHINA SEAS     

郑峰  岳彩军  陈佩燕  曾智华  雷小途  陈联寿  张灵杰 《热带气象学报(英文版)》2019,25(1):11-23

In this study, we employed National Centers for Environmental Prediction(NCEP)/National Center for Atmospheric Research(NCAR) reanalysis data and records from the China Meteorological Administration(CMA)Yearbook of Tropical Cyclones to investigate three factors: sea-surface temperature(SST), vertical wind shear(VWS),and the density of the core convection(DCC), which are responsible for the rapid intensification(RI) of 1949-2013 offshore typhoons. Our analysis results of these composite factors show that in the environmental wind field the typhoons are far away from the outer strong VWS; in the SST field they are in the high SST area; and the core convective activity is robust and takes a bimodal pattern. The difference in RI between typhoons over the East China Sea(ECS) and the South China Sea(SCS) is a smaller VWS for the ECS typhoons, which may be one of the reasons why typhoons in the ECS are more intense than those in the SCS. Our study results indicate that SST, VWS, and DCC can result in an RI after a certain time interval of 36 h, 24 h to 30 h, and 24 h, respectively. The RI indicates a lag in the atmospheric response to oceanic conditions. This lag characteristic makes it possible to predict RI events. In summary, where the SST is high(≥28 ℃), the VWS is small, and the DCC is high, an RI will occur. Where mid-range SSTs occur(26 ℃≤SST≤28 ℃), with small VWS, and high DCC, the RI of typhoons is also likely to occur.  相似文献   

西南低涡移动的初步分析     

卢敬华  雷小途 《成都信息工程学院学报》1996,(Z1)

从描述西南低涡运动的中尺度原始方程组出发，对低涡系统作水平分布的零阶Ｂｅｓｓｅｌ函数近似，在铅直方向上取６层斜压模式近似；导出了西南低涡移动速度的控制方程，得到了影响低涡移动的较为全面的因子，并通过对个例进行６层斜压模式的数值计算和诊断分析，找出了对低涡移动取决定性作用的决定性因子、一般影响因子、作用较小的修正因子和贡献极其在弱的不影响因子。然后分析和讨论了各因子对低涡移动作用的物理意义，为认识西南低涡移动的物理机制及用于业务预报提供参考。  相似文献   

气象灾害风险评估业务发展研究     

陈海燕  雷小途  潘劲松  张磊 《气象科学进展》2018,(4):15-21

根据气象灾害特点,对灾害风险评估的概念进行了再认识,分析比较了气象灾害与其他自然灾害(地震、地质灾害)风险评估的不同特点,气象灾害由于可预报性,其风险评估的应用范围更广、业务化能力相对更强;继而以浙江省为例,分析了防灾减灾以及主要行业的需求,以需求为牵引,分析了气象灾害风险评估的业务分类,提出了适应气象监测预报能力的五种风险评估服务产品。针对服务产品类型、空间精度、评估精度等开展了需求调查分析,结果表明:五种风险评估产品都有需求,其中实时综合类风险评估产品需求最大,灾后评估产品需求最小;空间尺度以县(市、区)和乡镇(街道)为单位的需求最大,其次以格点为单位;目前半定量化的"等级"评估精度基本满足服务需求,尚不具有一定精度的定量风险评估需求并不大。最后根据发展目标,架构了气象灾害风险评估的科学研究框架,提出了主要研究内容,初步分析了关键技术及解决方案。  相似文献