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1.
In order to provide an operational reference for tropical cyclone precipitation forecast,this study investigates the spatial distributions of precipitation associated with landfalling tropical cyclones(TCs) affecting China using Geostationary Meteorological Satellite 5(GMS5)-TBB dataset.All named TCs formed over the western North Pacific that made direct landfall over China during the period 2001-2009 are included in this study.Based on the GMS5-TBB data,this paper reveals that in general there are four types of distribution of precipitation related to landfalling TCs affecting China.(a) the South-West Type in which there is a precipitation maximum to the southwestern quadrant of TC;(b) the Symmetrical South Type in which the rainfall is more pronounced to the south side of TC in the inner core while there is a symmetrical rainfall distribution in the outer band region;(c) the South Type,in which the rainfall maxima is more pronounced to the south of TC;and(d) the North Type,in which the rainfall maxima is more pronounced to the north of TC.Analyses of the relationship between precipitation distributions and intensity of landfalling TCs show that for intensifying TCs,both the maximum and the coverage area of the precipitation in TCs increase with the increase of TC intensity over northern Jiangsu province and southern Taiwan Strait,while decreasing over Beibu Gulf and the sea area of Changjiang River estuary.For all TCs,the center of the torrential rain in TC shifts toward the TC center as the intensity of TC increases.This finding is consistent with many previous studies.The possible influences of storm motion and vertical wind shear on the observed precipitation asymmetries are also examined.Results show that the environmental vertical wind shear is an important factor contributing to the large downshear rainfall asymmetry,especially when a TC makes landfall on the south and east China coasts.These results are also consistent with previous observational and numerical studies. 相似文献
2.
利用CMORPH降水资料，将热带气旋（TC）登陆后的降水分为路径左侧降水（L型）和右侧降水（R型）两类，并针对登陆华东地区TC的 L型和R型降水的大气环流场、环境水平风垂直切变以及台风环流内的动热力条件进行对比分析，结果表明:2005～2014年间登陆华东地区的20例TC中包括12例L型和8例R型。总体来看，大气环流因子对于登陆华东TC降水分布起主要作用。L型降水TC高层南亚高压主要呈纬向带状分布，在登陆过程中路径左侧维持偏东风高空辐散气流，中层西风槽偏东，西太平洋副热带高压（简称副高）偏南，环境水平风垂直切变指向西南。R型降水TC高层南亚高压断裂，呈经向分布。TC路径左侧风场较均匀，右侧东南风高空辐散气流明显。副高的位置偏北呈块状，同时环境水平风垂直切变指向东北，有利于路径右侧降水。台风环流内，低层冷暖平流输送以及水汽辐合与降水落区也有较好对应关系。L型TC低层暖平流的输送使TC西南象限低层增暖，大气稳定度降低。同时水汽辐合区也主要位于西南象限，有利于TC路径左侧降水。而R型TC副高位置偏北可将南侧的东南暖湿气流向台风环流更西部输送，东北象限维持暖平流，有利于路径右侧降水发生。 相似文献
3.
Tropical cyclone (TC) rainfall asymmetry is often influenced by vertical wind shear and storm motion. This study examined the effects of environmental vertical wind shear (200-850 hPa) and storm motion on TC rainfall asymmetry over the North Indian Ocean (NIO): the Bay of Bengal (BoB) and the Arabian Sea (AS). Four TC groups were used in this study: Cyclonic Storm (CS), Severe Cyclonic Storm (SCS), Very Severe Cyclonic Storm (VSCS) and Extreme Severe Cyclonic Storm (ESCS). The Fourier coefficients for wave number-1 was used to analyze the structure of TC rainfall asymmetry. Results show that the maximum TC rainfall asymmetry was predominantly in the downshear left quadrant in the BoB, while it placed to downshear right quadrant in the AS, likely due to the different primary circulation strength of the TC vortex. For the most intense cyclone (ESCS), the maximum TC rainfall asymmetry was in the upshear left quadrant in the BoB, whereas it was downshear right quadrant in the AS. It is evident for both basins that the magnitude of TC rainfall asymmetry declined (increased) with TC intensity (shear strength). This study also examined the collective effects of vertical wind shear and storm motion on TC rainfall asymmetry. Here, the analysis in case of the strong shear environment (>7 m s-1) omitted for the AS because the maximum value for this basin was about 7 m s-1. The result showed that the downshear left quadrant was dominant in the BoB for the maximum TC rainfall asymmetry. In a weak shear environment (<5 m s-1), on the other hand, downshear right quadrant is evident for the maximum TC rainfall asymmetry in the BoB, while it placed dominantly downshear left quadrant in the AS. In the case of motion-relative wavenumber-1, the maximum TC rainfall asymmetry was dominantly downshear for both basins. 相似文献
4.
The mean kinematic and thermodynamic structures of tropical cyclones （TCs） making landfall in main-land China are examined by using sounding data from 1998 to 2009. It is found that TC landfall is usually accompanied with a decrease in low-level wind speed, an expansion of the radius of strong wind, weakening of the upper-level warm core, and drying of the mid-tropospheric air. On average, the warm core of the TCs dissipates 24 h after landfall. The height of the maximum low-level wind and the base of the stable layer both increase with the increased distance to the TC center;however, the former is always higher than the latter. In particular, an asymmetric structure of the TC after landfall is found. The kinematic and thermodynamic structures across various areas of TC circulation diff er, especially over the left-front and right-rear quadrants （relative to the direction of TC motion）. In the left-front quadrant, strong winds locate at a smaller radius, the upper-level temperature is warmer with the warm core extending into a deep layer, while the wet air occupies a shallow layer. In the right-rear quadrant, strong wind and wet air dwell in an area that is broader and deeper, and the warmest air is situated farther away from the TC center. 相似文献
5.
Observation from automatic weather stations, radars and TRMM satellites are employed
to investigate the precipitation distribution of tropical cyclone (TC) Koppu (0915) that made
landfall on Guangdong province in 2009. The results show that the precipitation of landfall TC
Koppu is featured by significant asymmetry and mesoscale structure, and occurs mainly to the
left of its moving path. By examining the sea surface temperature (SST), water vapor flux, Q
vector, vertical wind shear of environment etc., it is found out that the distribution of SST,
water vapor convergence, low-level convective ascending and vertical wind shear facilitates
the TC precipitation to take place to the left of the TC moving path. The mesoscale structure
separated by Barnes band-pass filter presents that the precipitation of landfall KOPPU has
some organized mesoscale spiral structures, which is around the TC center and composed of the
form of belts or blocks. The heavy local rainfall of landfall TC Koppu is primarily associated
with the rainfall due to mesoscale spiral structure. 相似文献
6.
Combined with TRMM products and Tropical Cyclone (TC) best track data in Northwest Pacific from 1 January 2003 to 31 December 2009, a total of 118 TCs, including 336 instantaneous TC precipitation observations are established as the TRMM TC database, and the database is stratified into four intensity classes according to the standard of TC intensity adopted by China Meteorological Administration (CMA): Severe Tropical Storm (STS), Typhoon (TY), Severe Typhoon (STY) and Super Typhoon (SuperTY). For each TC snapshot, the mean rainfall distribution is computed using 10-km annuli from the TC center to a 300-km radius, then the axisymmetric component of TC rainfall is represented by the radial distribution of the azimuthal mean rain rate; the mean rain rates, rain types occurrence and contribution proportion are computed for each TC intensity class; and the mean quadrantal distribution of rain rates along TCs motion is analyzed. The result shows that: (1) TCs mean rain rates increase with their intensity classes, and their radial distributions show single-peak characteristic gradually, and furthermore, the characteristics of rain rates occurrence and contribution proportion change from dual-peak to single-peak distribution, with the peak rain rate at about 5.0 mm/h; (2) Stratiform rain dominate the rain type in the analysis zone, while convective rain mainly occurred in the eye-wall region; (3) The values of mean rain rate in each quadrant along TCs motion are close to each other, relatively, the value in the right-rear quadrant is the smallest one. 相似文献
7.
登陆福建的热带气旋对广东降水的影响 总被引：1，自引：21，他引：1
普查1970~2005年登陆福建省的热带气旋(TC)资料可知:(1)36年间平均每年有1.4个TC登陆福建省,其中以强热带风暴及以上级别为主;6~10月都有TC登陆福建省,7~9月尤其8月份是登陆的高峰期;登陆福建的TC具有明显的年际变化。(2)登陆福建省的TC主要集中于3种路径:偏北、偏西、西北型路径,其中偏北、偏西型路径以登陆闽中、闽南为主,而西北型路径有一半登陆闽中,登陆闽北以及闽南的几率相当。(3)偏西型路径的TC登陆后仍以偏西或西南的路径移动,一般有西南季风的配合,80%对广东有显著影响;西北型路径的TC登陆闽北时由于继续以西北或偏北路径移动且在广东上空没有强劲的西南季风的配合,则对广东基本无影响,登陆闽中南的TC登陆后移向偏西或西南,或者有强劲的西南季风的配合对广东造成显著影响的占47.8%,而减弱快同时没有西南季风配合的形势则对广东的影响不显著。 相似文献
8.
登陆中国不同强度热带气旋的变化特征 总被引：4，自引：3，他引：1
根据《热带气旋等级》国家标准(2006),将热带气旋(TC)划分为热带低压(TD)、热带风暴(TS)、强热带风暴(STS)、台风(TY)、强台风(STY)、超强台风(SSTY)6个等级,利用中国气象局整编的1949—2006年共58年的《台风年鉴》和《热带气旋年鉴》资料,分析了登陆中国大陆、海南和台湾不同强度TC变化特征。结果表明：(1) 不同强度登陆TC频数存在年际和年代际变化,在长期趋势上,TD、TS登陆频数呈现显著的线性递减趋势,STY登陆频数呈现显著增加趋势。(2) 登陆TD、TS、STS存在6—8年的周期变化,TY具有准16年的周期变化。(3) 登陆TD、TS主要生成于南海东北部海面,登陆TY、STY、SSTY多生成于巴士海峡东南部海面和菲律宾以东洋面。(4) 在年代际变化上,南海生成的登陆TD、TS频数有减少趋势,TY、STY有增多趋势。 相似文献
9.
登陆台湾岛热带气旋强度和结构变化的统计分析 总被引：2，自引：0，他引：2
利用1949—2008年共60年的《台风年鉴》、《热带气旋年鉴》资料及CMA-STI热带气旋最佳路径数据集,2001—2008年美国联合台风警报中心(JTWC)热带气旋尺度相关资料及日本气象厅(JMA)的TBB资料,统计分析西北太平洋(包括南海)热带气旋(TC)在登陆台湾过程中强度和结构变化的基本特征,主要结论有:(1)TC登陆台湾时强度为台风及以上级别的样本数占总样本数约60%,主要出现在6—9月,东部登陆TC的强度一般比在西部登陆的强;(2)大部分TC在岛上维持6 h左右,登陆时最大风速≤5级和强度为超强台风的TC穿越台湾岛时移动比较缓慢;(3)126个登陆台湾的TC样本过岛后近中心海平面气压平均增加5.61 hPa,近中心最大风速平均减小3.58 m/s,在台湾东部地区登陆TC的衰减率比在西部登陆的大3倍左右;(4)TC在登陆台湾前6 h至离岛后6 h期间其8级和10级风圈半径均明显减小,TC形状略呈长轴为NE-SW向的椭圆状,而其最大风速的半径却逐渐增大;(5)TBB分析结果显示,TC登陆台湾前,其外围对流主要出现在南侧和西侧,结构不对称,登陆以后,TC北部及东部的对流显著发展,外围结构区域对称;但中心附近的强对流则从登陆前6 h开始逐渐减弱消失。表明TC穿越台湾过程中内核结构松散、强度减弱。 相似文献
10.
南海-西北太平洋地区大气准双周振荡对TC生成的调节作用 总被引：3，自引：1，他引：2
通过对南海-西北太平洋地区大气10～20 d准双周振荡(QBWO)不同位相的划分(A～D),研究了QBWO对南海-西北太平洋海域热带气旋(TC)生成的调节作用。将TC分为强热带风暴及以下级别(TS)和台风及以上级别(TY),并将QBWO分为干湿位相,发现南海海域生成的TS(TY)在干湿位相的比与西北太平洋海域生成的TS(TY)在干湿位相的比相等,这表明QBWO对TS(TY)生成的调节作用在南海和西太平洋地区可能相同。从A位相到C位相,南海和西北太平洋地区TC的生成频数均逐渐增多,D位相时期,TC生成最少,多数TC发生在QBWO的对流活动湿位相,少数TC发生在干位相。南海-西北太平洋海域TC的生成受到QBWO的明显调制。从位相A到位相C,低频对流和低频风场逐渐向西北方向移动,低频对流强度持续加强,低频风场逐渐由异常西风-东风-西风转为异常东风-西风-东风配置,西北太平洋地区季风槽加强,使得TC生成频数逐渐增多。此外,在QBWO活跃位相,非绝热加热增强和纬向风垂直切变减弱也有利于TC的生成。 相似文献
11.
利用逐小时风速观测资料以及台风年鉴资料,分析了2008~2014年登陆我国大陆地区的51次热带气旋（TC）的地面风场分布特征,包括TC登陆期间大陆地面风场演变和大风分布特征、海岛站和内陆站的风速差异以及海拔对风力造成的影响等。结果表明:6级及以上大风主要发生在距离TC中心300 km内、TC强度达到台风（TY）以上时,并主要位于TC移动方向的右侧,尤其是右前象限;华南区TC风场分布主要由在此区域登陆的TC（Ⅰ类）造成,较大风速区包括广东西南部沿海、雷州半岛附近和海南西部沿岸;华东区TC风场分布主要由在此区域登陆的TC（Ⅱ类）造成,杭州湾出海口以及浙闽沿海是较大风速区;6级及以上大风广泛分布在华南和华东沿海,6~7级地面大风高频站主要位于杭州湾附近,8级及以上地面大风高频站点在杭州湾和福建沿海分布比广东西南部更为密集;TC登陆前后均可能造成大风,大风出现时间与站点至TC中心的距离密切相关;同等强度TC在海岛站造成的风速比陆地站更大,对高海拔站点造成的风力大于低海拔站点。本文研究结论对于TC大陆地面风场的预报具有一定参考价值。 相似文献
12.
ASYMMETRIC DISTRIBUTION OF CONVECTION ASSOCIATED WITH TROPICAL CYCLONES MAKING LANDFALL ON THE EAST CHINA COAST 总被引：1，自引：1，他引：0
The asymmetric distribution of convection associated with tropical cyclones making landfall on the east China coast is studied with black-body temperature (TBB) data from Fengyun-2 (FY-2) geostationary weather satellite. The convection in various quadrants of the TCs is examined for the period of -24 to 6 h relative to landfall. The convection to the southern side of the TCs was much more intense than that to the northern side during the whole landfall period. The convection to the western side of the TCs was stronger than that to the eastern side for the time -8 h before and at the landfall. After landfall, the situation reverses. The asymmetric convection of the TCs was partly due to the vertical wind shear and storm motion, and partly because the process of landfall restrained the convection in relevant quadrants. Besides, the orographic uplift along the east of China was favorable to the enhancement of convection in the eastern side of the TCs. From the characteristics of convective asymmetry of the TCs landing on the south and east of China, it is known that their main difference might be the included angle between the TC path and the coastline as well as the terrain along the coast. 相似文献
13.
Tropical cyclone potential hazard in Southeast China and its linkage with the East Asian westerly jet 总被引：1，自引：0，他引：1
A new synthesized index for estimating the hazard of both accumulated strong winds and heavy rainfall from a tropical cyclone (TC) is presented and applied to represent TC potential hazard over Southeast China. Its relationship with the East Asian westerly jet in the upper troposphere is also investigated. The results show that the new TC potential hazard index (PHI) is good at reflecting individual TC hazard and has significantly higher correlation with economic losses. Seasonal variation of TC-PHI shows that the largest TC-PHI on average occurs in July-August, the months when most TCs make landfall over mainland China. The spatial distribution of PHI at site shows that high PHI associated with major landfall TCs occurs along the southeast coast of China. An East Asian westerly jet index (EAWJI), which represents the meridional migration of the westerly jet, is defined based on two regions where significant correlations exist between TC landfall frequency and zonal wind at 200 hPa. Further analyses show that an anomalous easterly steering flow occurred above the tracks of TCs, and favored TCs making landfall along the southeast coast of China, leading to an increase in the landfall TC when the EAWJ was located north of its average latitude. Meanwhile, anomalous easterly wind shear and positive anomaly in low-level relative vorticity along TCs landfall-track favored TC development. In addition, anomalous water vapor transport from westerly wind in the South China Sea resulted in more condensational heating and an enhanced monsoon trough, leading to the maintenance of TC intensity for a longer time. All of these environmental factors increase the TC potential hazard in Southeast China. Furthermore, the EAWJ may affect tropical circulation by exciting meridional propagation of transient eddies. During a low EAWJI phase in July-August, anomalous transient eddy vorticity flux at 200 hPa propagates southward over the exit region of the EAWJ, resulting in eddy vorticity flux convergence and the weakening in the zonal westerly flow to the south of the EAWJ exit region, producing a favorable upper-level circulation for a TC making landfall. 相似文献
14.
According to the national standard(2006)on tropical cyclone(TC)intensity,TCs are categorized into six intensity types,namely,tropical depression(TD),tropical storm(TS),severe tropical storm(STS), typhoon(TY),severe typhoon(STY),and super severe typhoon(SSTY).Fifty-eight years(1949–2006)of the datasets from the Yearbook of Typhoons and Yearbook of Tropical Cyclones were used to study the variation characteristics of TCs making landfalls in mainland China,Hainan and Taiwan islands.The main results are as foll... 相似文献
15.
1. IntroductionStudies on the tracks of tropical cyclones (TCs)have been one of the core problems in TC dynamics.In earlier researches, TCs are often viewed aspoint vortices, Rankine vortices. For example, Yeh(1950) and Kuo (1969), adopting dynamical methods,studied the motions of TCs and the effects of environ-ments. Their findings indicated that the motion tracksof TCs are characterized by cyclonic trochoidal oscil-lations.Syono (1955), by solving the barotropic vorticityequation, obta… 相似文献
16.
为进一步完善热带气旋大风风圈的分析和预报业务,利用中央气象台（NMC）发布的热带气旋报文资料、ERA5再分析资料,研究了2015年6月30日至2020年12月31日热带气旋最大强度时的7、10和12级风圈的非对称性特征及成因。统计结果表明: 热带气旋的7级风圈半径非对称性最大,10级次之,12级最小;非对称分布热带气旋的7、10和12级风圈最大半径大多分布在东北、东南和西北象限;同一热带气旋的7级和10级风圈最大半径大多分布在相同的象限。将7级风圈单一象限分布的热带气旋与多象限分布的热带气旋各按象限分布分成4类,分析4类7级风圈单一象限分布的热带气旋生成季节、地面10 m风特征及风圈非对称分布的成因发现:各类热带气旋具有明显的季节特征;地面10 m风场呈不对称分布;风圈非对称分布与西太平洋副热带高压、西南气流及地面冷高压等天气系统与热带气旋的相互作用造成的各象限位势高度梯度非对称分布密切相关。 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.
利用1985—2015年6—8月登陆中国东南部(福建和浙江)的35个西北行热带气旋(TC)和站点观测的日降水量,根据区域TC过程降水量,分为强降水、适量降水和弱降水TC,分析影响各级TC降水的环境场异常特征及其季节内振荡(ISO)的调制作用。(1)对流层低层850 hPa表现为中心位于福建东部强的气旋异常,来自孟加拉湾和南海强水汽输送在中国东南部产生强的水汽辐合促使TC强降水的发生,其中10~20天和30~60天ISO的环流和水汽输送都有贡献,但东南部的水汽辐合主要受10~20天ISO的影响;与TC强降水相比,TC弱降水对应的异常气旋和水汽辐合明显减弱。(2)影响TC强降水的10~20天ISO环流异常在TC登陆过程,自菲律宾群岛附近向西北方向传播至中国东南部,30~60天ISO环流异常自南海向东北偏北方向传播至台湾西南部,且环流异常强度不断加强。(3)影响TC弱降水的10~20天ISO环流异常自菲律宾西部向北传播,30~60天ISO环流异常自南海南部向东北方向传播。 相似文献
19.
登陆广东热带气旋的降水分布和移速变化 总被引：2，自引：4，他引：2
利用1980～2001年登陆广东的72个热带气旋的路径和降水资料,计算了热带气旋登陆前后的移动速度和加速度,比较分析了热带气旋主要降水落区与热带气旋移速变化的关系.计算结果统计表明登陆广东的热带气旋中,有66.1%的个例在登陆时移速加快.当主要降水落区位于热带气旋前进方向右侧时,热带气旋的12小时平均加速度为正的占了大部分(81.8%);当主要降水落区位于热带气旋前进方向左侧时,近八成(78.6%)的热带气旋平均加速度为负.这些统计结果进一步从诊断事实上说明了地形以及非绝热加热等因子对台风移动的可能影响. 相似文献
20.
A non-parametric method is used in this study to analyze and predict short-term rainfall due to tropical cyclones(TCs) in a coastal meteorological station. All 427 TCs during 1953-2011 which made landfall along the Southeast China coast with a distance less than 700 km to a certain meteorological station- Shenzhen are analyzed and grouped according to their landfalling direction, distance and intensity. The corresponding daily rainfall records at Shenzhen Meteorological Station(SMS) during TCs landfalling period(a couple of days before and after TC landfall) are collected. The maximum daily rainfall(R-24) and maximum 3-day accumulative rainfall(R-72) records at SMS for each TC category are analyzed by a non-parametric statistical method, percentile estimation. The results are plotted by statistical boxplots, expressing in probability of precipitation. The performance of the statistical boxplots is evaluated to forecast the short-term rainfall at SMS during the TC seasons in 2012 and 2013. Results show that the boxplot scheme can be used as a valuable reference to predict the short-term rainfall at SMS due to TCs landfalling along the Southeast China coast. 相似文献