热带气旋西行造成的远距离降雨特征分析

2018年7月27~28日凉山州地区出现了持续性的强降水天气过程,本文运用水平分辨率为1°×1°的NECP6小时再分析资料、新型监测资料及常规观测资料进行分析。发现此次过程不同于常规的降水过程,环流背景上受副高外围的东南气流和热带气旋形成的东风波倒槽共同作用形成的急流轴影响,为降水地提供充足的水汽和能量补充,从而形势上形成了热带气旋远距离降水,同时副热带高压的稳定维持也阻挡了高原上的低值系统快速东移,使得降水机制长时间停滞,对降水地造成影响。     

1994年影响山东的热带气旋分析

１９９４年为影响我国的热带气旋明显偏多年。利用常规天气图和海温资料，对本年度登陆北上热带气旋偏多的环流背景和海温场特征进行了分析，指出，西太平洋副热带高压稳定偏北和海面温度明显偏高，是北上热带气旋偏多的主要原因。同时，还对热带气旋移动路径、所在位置与山东降水的时空分布及降水强度之间的关系进行了简单的统计分析，其结果可供热带气旋的业务预报参考。     

一种识别热带气旋降水的数值方法

提出了一种有于识别热带气旋降水的数值方法。这一方法是在中国国家气候中心与美国国家气候资料中心的双边合作研究中得以实现的。该方法的识别结果与天气图人工判别结果相比较表明，两者结论十分一致。     

热带气旋BOLA产生的温带降水的诊断研究

热带气旋ＢＯＬＡ产生的温带降水的诊断研究１引言热带气旋Ｂｏｌａ（１９８８年３月）是袭击新西兰的最有破坏力的风暴之一，给这个国家带来了人们记忆中最大的一次降雨。本研究采用欧洲中心中期天气预报初始化分析结合观测资料来描述这一事件，并评价与这场雨有关的动力...     

热带气旋与文昌降水

通过研究热带气旋的活动规律以及对文昌天气的影响,揭示了各类路径的热带气旋在不同的位置与文昌降水的关系。     

热带气旋远距离暴雨的研究

用中国国家气象信息中心整编的1971-2006年中国693个地面基准站日降水资料、同期美国JTWC最佳路径资料和NCEP/NCAR再分析资料,对热带气旋(TC)远距离暴雨进行统计分析和诊断研究.结果表明:36 a中有14.7％的TC产生远距离暴雨.TC远距离暴雨事件遍及中国大陆27个省(市、自治区),其中,环渤海地区和川陕交界处为中国TC远距离暴雨高发区.远距离暴雨集中发生在6-9月.34.6％的TC远距离暴雨具有影响范围广、降水强度大的特点.诊断分析表明,TC远距离暴雨能否产生的关键在于热带气旋东侧环流能否将水汽输送到中纬度槽前,如果有高气压或偏北气流对水汽输送的阻断,就不会形成远距离暴雨.     

STATISTICAL ANALYSIS OF SUMMER TROPICAL CYCLONE REMOTE PRECIPITATION EVENTS IN EAST ASIA FROM 2000 TO 2009 AND NUMERICAL SIMULATION

Using 1°×1° final analysis(FNL) data from the National Centers for Environmental Prediction(NCEP),precipitation data from the Tropical Rainfall Measuring Mission(TRMM) and the best-track tropical cyclone(TC)dataset provided by the Japan Meteorological Agency(JMA) for June-August of 2000-2009, we comprehensively consider the two factors low-level moisture channel and interaction between TCs and mid-latitude systems and implement a statistical analysis of remote precipitation in East Asia to the north of 0° and to the west of 150° E. 48 cases of remote precipitation occurred in this period, which are categorized into five classes. After a composite analysis of the different classes, the main systems at 850 h Pa and 500 h Pa that impact the remote precipitation are as follows:TC, mid-latitude trough, subtropical high and water vapor channel. In particular, the water vapor channel which usually connects with Indian monsoon has the most significant impact on remote heavy rainfall. Another important factor is the mid-latitude trough. The type of north trough/vortex-south TC remote precipitation events happen most frequently,accounting for 68.8% of the total incidence. Most remote precipitation events occur on the right side of the TC path(representing 71% of the total number). At 200 h Pa, the remote precipitation events usually occur on the right rear portion of a high-altitude jet stream, and there is an anti-cyclonic vortex to the east and west of the TCs. When there is no anti-cyclonic vortex to the east of the TC, the TC is relatively weak. When the remote precipitation occurs to the northwest of the TC and there is a trough in the northwest direction, the TC is relatively strong. Numerical experiments are carried out using Weather Research and Forecast(WRF) model. The results shows that the TC plays a main role in producing the heavy precipitation and results in the enhancement of precipitation by impacting the water vapor channel.     

热带气旋中β偶极涡的数值模拟

通过数值模拟来研究热带气旋中的β偶极涡环流，结果可见，在中层的偏差流场上，有清晰的β偶极涡环流，即涡旋中心以西为气旋性环流，以东为反气旋性涡旋，理论分析表明，该β偶极涡环流是由地转涡度平流造成的。     

海洋飞沫对热带气旋影响的数值试验

将最新版的Andreas海洋飞沫通量参数化方案与中尺度大气模式MM5V3耦合,对0514号热带气旋Nabi进行数值模拟,探讨海洋飞沫蒸发对热带气旋发展和演变的影响.模拟结果表明,考虑海洋飞沫的作用后,热带气旋范围内(气旋中心附近600 km左右范围内)的潜热和感热通量明显增强,尤其是潜热通量,最大值可提高35%～80%,潜热通量的大值区对应热带气旋眼墙处的最大风速区.无论是否考虑海洋飞沫作用,模式均能较好地模拟出热带气旋Nabi的移动路径,但考虑飞沫作用后,由于飞沫对海气界面通量交换的贡献,使得模拟热带气旋中心的最低海平面气压降低,最大风速增强,暖心结构更加明显.     

台风远距离暴雨的研究进展

台风是最强的暴雨天气系统，针对台风暴雨的研究由来已久，并把台风暴雨分为台风环流本身的暴雨和台风远距离暴雨。近几十年来，有关台风远距离暴雨的研究有了一些新的进展和成果。2007年的第十四届全国热带气旋研讨会上还给出了最新的台风远距离暴雨定义。谨从此定义出发，简要总结国内外在台风远距离暴雨方面的研究成果，并在分析归纳的基础上提出存在的问题和可能的研究方向。     

一种初始涡旋重定位方法及热带气旋路径数值模拟试验

采用平滑滤波和柱形滤波技术,从背景场中分离出初始涡旋环流和大尺度环境场,然后把分离出的涡旋环流进行平移和再植入到观测位置,最终得到一种初始涡旋重定位方法。针对2006—2007年7个热带气旋共23个时次,采用背景场直接加入热带气旋bogus模型和背景场进行初始涡旋重定位后加入热带气旋bogus模型2种方案,分别进行了对比模拟试验。结果表明:对背景场进行初始涡旋重定位后加入热带气旋bogus模型的方案模拟的24和48小时热带气旋路径平均误差都相对较小,初始涡旋重定位方法可以减小热带气旋模式因热带气旋初始位置偏差而引起的误差,有助于提高热带气旋模式的路径预报水平,有较好的业务应用前景。     

NUMERICAL STUDY ON NONLINEAR INTERACTION BETWEEN TROPICAL CYCLONE AND SEA

Given time-independent monthly mean sea temperature,numerical simulation was done of the path of the tropicalcyclone Forrest and its related physical quantity field in terms of the improved version of the σ-coordinate 10-levelprimitive equation model for tropical cyclones developed by the Guangzhou Institute of Marine Meteorology.Resultssuggest the similarity between the simulated and observed physical quantity fields except that the simulated path was tothe right of the observed,with the deviation increasing with time.Sea and tropical cyclone,in effect,interact mutually.In an attempt to compare the results from coupling anduncoupling experiments,an oceanic mixed layer model was formulated based on experiments with sea response to cy-clone and integrated in synchronous coupling with the aforementioned version of tropical cyclones,the computationaldomain covering the western North Pacific with the coastal configuration involved.The coupling experiment shows thatthe negative feedback of the interaction between sea and mature cyclone leads to weaker sea response as compared to theuncoupling case.Except for the location of the divergence core of oceanic current,the mixed layer depth andinhomogeneous distribution of sea surface temperature (SST) caused by the cyclone-core position and intensity,the val-ues of the maximum oceanic current,departure of the mixed layer depth and SST drop were smaller in the coupling thanin the uncoupling case,and so was the maximum wind near the cyclone core.The path from the coupling run is to theleft of the course in the uncoupling experiment but closer to the observed one though remaining somewhat leftward.Even on a scale of less than 3 days,the effects of sea and sea-cyclone interaction on the cyclone were by no means negli-gible.     

NUMERICAL STUDY ON FUNCTIONS AFFECTING TROPICAL CYCLONE STRUCTURE AND MOTION

By using a beta-plane quasigeostrophic barotropic model,four numerical experiments withintegration time more than five days are performed.Results show that the vorticity advection termand beta term are two basic factors significantly affecting tropical cyclone structure and motion.     

A NUMERICAL EXPERIMENTAL STUDY OF TROPICAL CYCLONE CROSSING SUBTROPICAL HIGH

The barotropic primitive equations model is used in a numerical study of a tropical cyclone crossing the Subtropical high. It is revealed that apart from its own characteristics, sensitive factors having immediate effects on the motion of the tropical cyclone also include its radial distance from the center of the subtropical high, the variation in latitudinal location and intensity. A complex mechanism for nonlinear interactions among the tropical,subtropical high and β effect is also shown in the experiment, and expected to serve for the diagnosis and prediction of abnormal motion.     

NUMERICAL SIMULATION OF TROPICAL CYCLONE MOVEMENT WITH THE RELATED CRITICAL POINT PHENOMENON

A study is made of the paths of tropical cyclones under the joint action of environmental flow and heating fields interms of a quasi-geostrophic barotropic model with the thermal forcing and dissipation terms involved,in which 16 ex-periments are designed and integrated for more than 7 model days.Results show that for different parameter values ofthe environmental flow and heating field,and the cyclone scale, such paths as counterclockwise looping, zigzag form andwestward march with an abrupt turning towards the north are reproduced clearly in the model atmosphere,exhibitingtheir critical points of nonlinear character.