共查询到19条相似文献，搜索用时 125 毫秒
1.
为进一步认识影响台风强度预报的因素,提升对台风最大强度预报的能力,利用高精度集合模拟试验对2020年第4号台风“黑格比”的发展增强过程进行了分析,探讨了初期涡旋和大尺度环境背景对台风最大强度的影响。结果表明：描述初期台风涡旋特征的10 m最大轴对称切向风、最大风速半径附近及其外侧低层的轴对称切向风和入流以及涡旋的丰满度均与台风最大强度有较好的相关：最大轴对称切向风能够更早且更准确地指示台风最大强度;最大风速半径附近及其外侧低层的轴对称切向风和入流越强,其伴随的向台风内核区输入的角动量越大,台风的最大强度也越强;初期台风涡旋的丰满度与最大强度的相关远高于外围风圈和最大风速半径与最大强度的相关,意味着对于小台风“黑格比”而言,只要初期涡旋丰满度大,其最大强度也会很强。“黑格比”的最大强度与其西侧“森拉克”台风和东侧副热带高压也密切相关,若这两者都偏强,不仅使得“黑格比”引导气流的向北分量偏强,导致台风快速北移受到干空气影响,还会使得“黑格比”的环境风垂直切变增大,不利于台风达到更强的最大强度。对于这类台风而言,初始涡旋结构和邻近台风及副热带高压的准确描述是提高台风最大强度预报能力的重要前提... 相似文献
2.
双台风涡旋运动及其相互作用的数值研究 总被引：2，自引：1，他引：2
本文采用正压原始方程模式对不同强度、间距和基本气流条件下的双台风涡旋作了一系列数值试验,试验结果表明:在无环境风场条件下,双台风在某一临界距离内作明显的相互旋转运动,这个临界距离是随台风强度以及风场分布的特征而改变的。双台风有明显的相互吸引作用的临界距离远小于相互旋转的临界距离。双台风相互旋转速率与台风强度成正比、与台风切向风速向外减小率和台风中心的间距成反比。均匀的环境气流对双台风相互作用影响甚微,但有了基本气流以后,两个台风对基本气流的扰动具有不同敏感性。在西风基本气流中,西台风移动稳定而东台风移动稳定性差。在有切变的环境气流中,台风运动既受环境气流的平流作用也受β效应作用和台风相互作用,当台风中心间距大于相互旋转的临界距离时,主要受环境气流和β效应作用。此外,本文还把试验结果与西北太平洋的台风统计资料作了比较,並讨论了试验结果对预报的启示。 相似文献
3.
涡旋Rossby波传播和台风切向风速变化的数值研究 总被引：1，自引：0，他引：1
余锦华 《南京气象学院学报》2003,26(2):172-180
设计了一个高分辨率f平面准地转正压涡度方程半谱模式，用以研究非线性对台风切向风速变化，以及不同初始异常条件下台风环流内涡旋Rossby波传播和台风切向风速变化特征。6类(14组)试验的数值结果表明：非线性使台风切向风速的增强减弱，可能使最大风速半径收缩。初始扰动中心位置对涡旋Rossby波传播和台风切向风速变化的影响明显。扰动中心在最大风速半径附近时，台风最大切向风速增强最多；异常中心在台风外区时，使最大切向风速减小。初始异常尺度(范围)减小对台风最大切向风速变化的影响减弱。双涡分布条件下，台风环流外区的涡旋使内区或近眼壁区对流涡旋对台风最大切向风速的影响减弱。 相似文献
4.
本文使用柱坐标系下的正压浅水方程组以及斜压扰动方程组,分析得出台风涡旋系统中的涡旋Rossby波划分为两种类型。由于切向基本气流的二阶径向水平切变或者基本气流的垂直涡度在径向方向的变化(β*因子)所导致的涡旋Rossby波称之为第一类涡旋Rossby波(正压涡旋Rossby波),它产生的根本原因是β*因子的作用。这种第一类涡旋Rossby波相对于切向基本气流是单向传播的,其传播方向则与β*因子的正负符号有关。当基本流场垂直涡度-ζz沿着径向r方向增大时,第一类涡旋Rossby波是沿着切向圆周方向逆时针方向传播的;反之则是沿着切向圆周方向顺时针方向传播。如果考虑切向基流的二次垂直切变时,可以得到台风涡旋系统中第二类涡旋Rossby波(斜压涡旋Rossby波)的相速度表达式,第二类涡旋Rossby波产生的物理根源是切向基本流场风速的二次垂直切变或者基本流场径向r方向的平均涡度在空间z方向上的不均匀性(亦即β**因子)。第二类涡旋Rossby波相对于切向基本气流也是单向传播的,当-ζr沿着空间z方向上增大时,第二类涡旋Rossby波就是相对于基本气流-V0是顺时针方向传播的;反之则是相对于基本气流逆时针方向传播。在基本流场的风速-V存在二次径向水平切变或者垂直切变时,台风中的波动可能是混合的涡旋Rossby波——重力波;而当基本流场的风速-V仅仅存在线性切变,不存在二次切变时,此时根本不存在涡旋Rossby波,台风系统中的波动则仅仅是重力惯性波。最后,采用WRF模式对“云娜”台风进行了数值模拟,验证了上述结论。 相似文献
5.
环流非对称结构与台风移速关系的数值研究 总被引：4，自引：0，他引：4
利用准地转正压模式,在无环境气流的情况下,对初始轴对称和非轴对称理想台风实施两组共13个数值试验,研究台风环流不同区域的非对称性与其移速的关系。结果表明：（1）台风环流某些区域的非对称性与其移速有稳定的强相关,如,大风半径外围50～100KM附近东—西向东北—西南向的非对称性;（2）大风半径的位角,使台风外围环流的非对称性与其移速相关增强,而最大风速和初始非对称方位用的变化对上述相关性几乎没有影响。 相似文献
6.
热带气旋强度影响其移动的物理机制 总被引：3，自引：2，他引：3
应用无基本气流的无辐射正压模式研究热带气旋强度影响其移动的物理机制，结果表明，（１）弱（强）热带气旋的大度尺β涡旋弱（强）通风气流速度小（大），因而其移速慢（快）（２）弱的与强的热带气旋的大尺度β涡旋的方位位相之差，通风气流方向之差都很小，因此其移向的差别也很小；（３）热带气旋移速振荡和移向摆动的周期与小尺度涡旋活动的周期相接近，在热带气旋内部区域；弱（强）热带气旋的切向风速小（大），小尺度涡旋活 相似文献
7.
1330号台风海燕强烈发展和快速移动原因分析 总被引：3，自引：1，他引：2
本文运用NCEP再分析资料(水平分辨率1°×1°,垂直层次26层)和各种常规观测资料以及中央气象台台风实时定位定强数据对2013年全球最强台风海燕的特点和极端性展开分析,并运用天气学分析和动力学诊断的方法探讨"海燕"强度发展的动力机制和快速移动的原因,同时发掘预报着眼点,以提高中央气象台对类似台风的综合预报能力。本文主要研究结论为:(1)"海燕"在登陆菲律宾之前的持续加强和高强度维持发生在副热带西风急流加强南压和副热带高压南侧对流层各层低纬东风同时加强的条件下。(2)副热带西风急流加强南压是导致西太平洋副热带高压加强和副热带高压南侧对流层各层低纬东风加强及"海燕"高速靠近并登陆菲律宾的重要原因。(3)"海燕"的水平风速分布存在明显不对称,呈现台风北侧东风大于南侧西风、台风东侧南风大于西侧北风的特点,其中纬向风的不对称更显著。而由台风海燕东西两侧经向风和南北两侧纬向风的不对称分布导致的切变正涡度的增加可能是台风强度持续增强的重要原因之一。(4)对流层低层水平辐合的显著加强和台风海燕南北两侧经向垂直环流圈的加强和建立也是"海燕"强度持续加强的重要原因之一。(5)台风海燕持续加强和高强度维持的主要动力机制为内核区对流层低层水平辐合和对流层中低层涡度的持续增长以及台风所处环境的高层辐散的明显增加和高低层垂直切变的减小。(6)预报启示为:对于秋冬季的台风而言,除了西太平洋副热带高压、西风槽、对流层低层偏东风、越赤道气流外,还需关注对流层上层副热带西风急流的变化,特别是对于偏西行台风而言,副热带西风急流的加强南压可能会导致台风移速的加快和强度的明显加强。另外对流层上层不光是台风的出流层,能影响台风高层出流的变化,对流层上层的环流还可能对台风移动造成一定影响。 相似文献
8.
针对1980～1996年间发生在南海地区的两类中层气旋（MTC）典型个例分别进行合成分析,研究了它们的结构特点。研究发现,西风扰动类MTC在强度上要强于东风扰动类MTC;而东风扰动类在垂直三维结构上随高度向西南方向倾斜的程度远远大于西风扰动类,但它们都是一种冷心结构并且随高度向西南方向倾斜的系统。两类中层气旋的涡度、风速都在中层有最大值,对流层中层为辐合区,300hPa以上为补偿辐散区,垂直上升运动在400hPa达到最大。分析各自的演变过程,发现在MTC的发展过程中,西风扰动类MTC基本处于准静止状态略有西移,而东风扰动类MTC由于其发展过程的独特性,往往向西北方向移动并且移速较大。东风扰动类MTC所在的位置较西风扰动类MTC偏高,这是由于夏季南海地区处于西南季风控制下,东风气流所在位置偏高所致。我们还发现西风扰动类MTC西边的西风气流与MTC发展过程相对应有一个风速加大、维持和减弱的过程;东风扰动类MTC东面的东风气流也有类似过程。同时,与两类MTC相对应的代表副高强度的东风气流随MTC发展的演变表明,当有西风扰动类MTC时,副高有减弱的征兆,而有东风扰动类MTC时,副高并未减弱,反而东风有所加强。对1998年个例进行数值实验表明：MTC系统的对流加热在500hPa达到最大,且对流加热对MTC的发展具有很重要的作用,对流加热越弱,系统发展越弱。 相似文献
9.
运用热带气旋曲率理论模型，选择不同环境及移速特征的台风个例，通过动力学诊断分析，揭示了台风异常运动的关键影响因子的物理机制及其规律。研究结果表明，热带气旋曲率理论模型中影响台风移动的相关特征能够在一定程度上描述出天气系统等环境因子对台风异常运动的综合影响规律。诊断分析结果表明，台风移速、涡旋动力结构、外围副热带高压带及西风槽的非定常变化均可影响台风移动轨迹曲率，尤其是对异常路径和转向点的影响，其突变规律符合台风移动规律。台风移动与系统动力结构有关，台风最大风速与中心气压突然增强或减弱时都会导致台风的突然转向。 相似文献
10.
2016年中国国家气象中心区域台风模式（GRAPES_TYM）对第18号热带气旋（记为TC 1618）的路径预报出现了较大的误差:其平均路径误差显著大于全年的平均误差。分析了涡旋初始化方案（包括涡旋重定位以及涡旋强度调整）对其路径预报的影响。结果显示,涡旋强度调整是造成TC1618预报路径平均误差偏大的主要原因。不同的强度调整半径（r0=12°,9°,6°,3°）对TC1618路径影响的敏感性试验结果显示,强度调整半径越大,其平均路径预报误差越大。500 hPa副热带高压以及平均海平面涡旋尺度分析发现:较大的强度调整半径（r0=12°,9°）其初始时刻的涡旋尺度较大,涡旋北侧邻近区域副热带高压等值线相对偏北,副热带高压相对偏弱。尺度大的涡旋其北移速度较大,并且在积分过程中其环流邻近区域副热带高压进一步减弱,导致涡旋环流会更早与其西北侧东移的西风槽结合,移速偏快。 相似文献
11.
Typhoon is regarded as a convergent,modified Rankine vortex.Based on the vorticity equations written attwo levels,higher and lower in the troposphere,typhoon motions are discussed in this study.The analyticalexpressions of vortex motion direction and speed have been derived for simple homogeneous basic flows at twolevels.The expressions indicate that in the easterties,vertical wind shear enhances the steering of east flow,causing the vortex moving westward faster,otherwise,in the westerlies,it reduces the steering of the west flow,causing the vortex moving eastward slower.These results explain theoretically that“cyclones in the easterliesmove to the right of,and faster than the basic flow;conversely,cyclones in the westerlies move to the left of,andslower than the basic flow.” 相似文献
12.
IMPACTS OF UPPER-LEVEL COLD VORTEX ON THE RAPID CHANGE OF INTENSITY AND MOTION OF TYPHOON MERANTI (2010) 总被引：2，自引：0，他引：2
Typhoon Meranti originated over the western North Pacific off the south tip of the Taiwan Island in 2010.It moved westward entering the South China Sea,then abruptly turned north into the Taiwan Strait,got intensified on its way northward,and eventually made landfall on Fujian province.In its evolution,there was a northwest-moving cold vortex in upper troposphere to the south of the Subtropical High over the western North Pacific(hereafter referred to as the Subtropical High).In this paper,the possible impacts of this cold vortex on Meranti in terms of its track and intensity variation is investigated using typhoon best track data from China Meteorological Administration,analyses data of 0.5×0.5 degree provided by the global forecasting system of National Centers for Environmental Prediction,GMS satellite imagery and Taiwan radar data.Results show as follows:(1)The upper-level cold vortex was revolving around the typhoon anticlockwise from its east to its north.In the early stage,due to the blocking of the cold vortex,the role of the Subtropical High to steer Meranti was weakened,which results in the looping of the west-moving typhoon.However,when Meranti was coupled with the cold vortex in meridional direction,the northerly wind changed to the southerly at the upper level of the typhoon;at the same time the Subtropical High protruded westward and its southbound steering flow gained strength,and eventually created an environment in which the southerly winds in both upper and lower troposphere suddenly steered Meranti to the north;(2)The change of airflow direction above the typhoon led to a weak vertical wind shear,which in return facilitated the development of Meranti.Meanwhile,to the east of typhoon Meranti,the overlapped southwesterly jets in upper and lower atmosphere accelerated its tangential wind and contributed to its cyclonic development;(3)The cold vortex not only supplied positive vorticity to the typhoon,but also transported cold advection to its outer bands.In conjunction with the warm and moist air masses at the lower levels,the cold vortex increased the vertical instability in the atmosphere,which was favorable for convection development within the typhoon circulation,and its warmer center was enhanced through latent heat release;(4)Vertical vorticity budget averaged over the typhoon area further shows that the intensification of a typhoon vorticity column mainly depends on horizontal advection of its high-level vorticity,low-level convergence,uneven wind field distribution and its convective activities. 相似文献
13.
A tropical cyclone is a kind of violent weather system that takes place in warmer tropical oceans
and spins rapidly around its center and at the same time moves along surrounding flows. It is generally
recognized that the large-scale circulation plays a major role in determining the movement of tropical
cyclones and the effects of steering flows are the highest priority in the forecasting of tropical cyclone
motion and track. This article adopts a new method to derive the steering flow and select a typical
swerving track case (typhoon Dan, coded 9914) to illustrate the validity of the method. The general
approach is to modify the vorticity, geostropical vorticity and divergence, investigate the change in the
non-divergent stream function, geoptential and velocity potential, respectively, and compute a modified
velocity field to determine the steering flow. Unlike other methods in regular use such as weighted average
of wind fields or geopoential height, this method has the least adverse effects on the environmental field
and could derive a proper steering flow which fits well with storm motion. Combined with other internal
and external forcings, this method could have wide application in the prediction of tropical cyclone track. 相似文献
14.
贺海晏 《热带气象学报(英文版)》1995,1(1):12-22
A basic equation governing the movement of a typhoon has been derived based on the system of primitive equations of motion in the atmosphere. The role of several forcing factors which cause the deviation of the typhoon from the steering current have been discussed based on the governing equation. What is presented in Part Ⅰ is a theoretical analysis on the effects of diabatic heating and the horizontal temperature distribution. It is shown that the accelerations of a typhoon caused by diabatic heating and temperature advection coincide with the direction of the volume-averaged "diabatic steering velocity" QV and the "steering velocity of temperature advection" ATV (V is the air velocity,Q the diabatic heating rate and AT the temperature advection ), respectively. The precipitation (or condensation heating) on the right (left) side of a typhoon will accelerate (decelerate) the typhoon. The precipitation in the front (rear ) of the typhoon will turn it to the left (right) of its ordainal path. A typhoon will speed up (slow down) when it moves towards a region of cold (warm) air. 相似文献
15.
用一个高分辨率的 f平面正压涡度方程模式 ,实施了时间积分为 36h的 2 1组试验 ,研究相邻中尺度涡旋与台风涡旋的相互作用。结果指出 :这种相互作用能否导致台风加强 ,取决于两类因子 :一是台风涡旋最大风速的取值以及圆形基流切变的强弱 ;二是切变基流中的中尺度涡旋的自身条件 ,包括中尺度涡旋的分布、尺度、强度和结构。台风强度与初始中尺度涡旋的尺度、强度之间存在着非线性的联系 相似文献
16.
Recurvature dynamics of a typhoon 总被引：1，自引：0，他引：1
T. N. Krishnamurti H. S. Bedi K. S. Yap D. Oosterhof G. Rohaly 《Meteorology and Atmospheric Physics》1992,50(1-3):105-126
Summary In this paper we present some recent work on typhoon prediction with a high resolution global model. The emphasis of this paper is on typhoon recurvature. Here we include examples of successful typhoon recurvature track forecasts made from a very high resolution global spectral model. The main objective of this study however is to go beyond the forecasts, i.e. to interrogate the history tapes and to diagnose residue-free budgets of the divergence and vorticity. The premise of this paper is that the recurvature of the typhoons depends on both the usual advection of vorticity by the layer mean winds and the advection of divergence in the outflow layers of the storm.The region immediately outside the heavy rain area of the storm experiences large values of divergent outflows which contribute a significant advection of divergence. Through the Dine's compensation this region must, in consort, experience an enhancement of low level convergence and of deep convection, thus contributing to the storm motion. We distinguish two facets of storm motion and recurvature, one based on the conventional steering that invokes the advection of vorticity by a vertical integrated flow, the other is the generation mechanism proposed here. During recurvature the storm appears to move in a direction which is influenced by the rotational and the divergent flow dynamics. Increased vertical resolution in the outflow layer is shown to resolve stronger amplitudes in the outflow layer divergence and thus to contribute to improved forecasts of recurvature. A number of processes seem to simultaneously evolve, these include the strong advection of divergence part of the wind, enhancement of cumulus convection over this region, an enhancement of lower tropospheric convergence, generation of vorticity of the lower troposphere and the attendant recurvature.With 16 Figures 相似文献
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1 INTRODUCTION The typhoon is a destructive weather phenomenon that stands at the top of ten major natural disasters[1]. Typhoon-related damages are the immediate consequences of weather it brings forth, which include heavy rain, strong winds and storm surges (water gain). They cause flash floods, bring down houses and break through dams[1]. Of the research on typhoons for the recent 10 years[2], new advances have been reported on abrupt changes in the motion, structure and intensity of… 相似文献
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我寫這篇文章的動機是由於繪製中國之温度圖而起,當我作温度圖時.發现一個特殊的現象,就是中國東部沿海岸及以島嶼上的温度,常是比較兩旁的温度為低。就是說比左邊的大陸和右邊的大洋,温度統要低些,這可拿年平均温度來代表(第一圖)。這種現象在中國東岸有兩個區域特别顯著,一個是山東半島東端和江蘇北部的東海徐州一带,一個是在台灣海峽内。我們名上述兩個區域,一個為黃海西區一,個為台灣海峽區。在這兩個區域内,等温線的分布,格外特别。如黃海西區,等温線在山東半島南部向陸地突入,經東海徐州成一舌狀。 相似文献