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1.
2008年西北太平洋热带气旋活动特征分析 总被引：2，自引：1，他引：1
对2008年西北太平洋及我国南海热带气旋的活动特征进行总结,并从多方面分析其成因.结果指出:2008年西北太平洋热带气旋活动的主要特征为生成总数少,源地集中,位置偏西;登陆数多、时间早;登陆地点偏南、时间集中等.其原因主要在于:在热带气旋的多发期副热带高压面积偏大、强度偏强、西伸脊点异常偏西,且脊线偏南,造成西北太平洋热带地区盛行偏东风,不利于热带扰动的生成和发展;同时,也使得在其南侧生成的热带气旋易在偏东气流的引导下登陆我国南方.另外,季风槽、垂直风切变、海表温度和热带辐合带上的对流活动等因子的异常分布都不利于热带气旋在西北太平洋东部海域生成,直接导致这一年热带气旋生成总数明显偏少,源地显著偏西. 相似文献
2.
1994年西北太平洋(包括南海)共生成热带气旋37个(包括:台风、强热带风暴和热带风暴),其中19个发展成台风。有12个热带气旋在我国登陆,比常年(9.3个)偏多。9417号台风在浙江登陆,对浙江影响很大。另外,125°E以西近海北上的热带气旋有3个较常年略偏多,明显多于去年,对浙江沿海影响较大。热带气旋路径以中低纬西,西北行,中纬北上转向型为主。登陆我国的热带气旋位置比常年偏北。 相似文献
3.
赤道中东太平洋表层水温异常与热带气旋活动的统计关系 总被引：7，自引：4，他引：3
利用1950-2005年西北太平洋热带气旋(TC)和赤道中东太平洋表层水温(SST)资料,统计分析了赤道中东太平洋表层水温异常与TC频数、强度、源地和路径等的关系.结果表明,赤道中东太平洋暖异常年:(1)TC发生频数偏少,较常年平均偏少2～3个,但强度偏强,强台风和超强台风发生数偏多,较常年平均偏多1个左右,且随着暖异常强度的增强,TC发生频数偏少,强度增强愈加明显;(2)TC生成位置偏东偏南,145°E以东海区TC生成频数较冷异常年和La Nina年增加明显;(3)TC路径偏东,转向路径出现频次增加,西向路径出现频次减少,从而导致日本东部海区TC通过频数增加,而我国南海和华东沿海TC通过频数减少;(4)在我国登陆的TC频数偏少,较常年平均偏少1～2个.赤道中东太平洋冷异常年,情况基本与上相反.上述影响主要是由于赤道中东太平洋SST异常导致大气环流发生异常造成的. 相似文献
4.
越赤道气流准双周振荡对西北太平洋台风路径的调制作用 总被引：4，自引：4，他引：0
利用美国联合台风预警中心（Joint Typhoon Warning Center,JTWC）热带气旋（tropicalcy—clone,TC）数据、NCEP／NCAR再分析风场资料,研究了越赤道气流准双周振荡对西北太平洋台风路径的调制作用。将西北太平洋台风路径划分为：西行路径、西北行路径、转向登陆中国路径、转向中日之间路径、转向登陆日本路径、转向日本以东路径和140°E以东路径。利用超前滞后回归方法,合成分析了6—10月不同路径台风对应的越赤道气流准双周振荡的低频环流演变过程。结果表明,925hPa越赤道气流及与其相联系的经向风存在明显10～20d准双周振荡现象,且对西北太平洋台风路径预报具有一定的指示作用。在西太平洋赤道地区,低频越赤道气流强度、演变特征影响着西北太平洋低频气旋的位置和移动方向,调节风场强辐合带与季风槽的位置与强度,继而对台风生成位置、移动路径产生重要的影响。初步认为,强向北低频越赤道气流分量有利于北侧低频气旋加强和向北传播,继而使得强辐合带、季风槽位置偏北,台风易于在此区域生成且沿着强辐合带位置移动。而弱向北低频分量或向南低频分量则不利于台风转向移动。 相似文献
5.
通过统计分析,本文研究了强El Ni〖AKn~D〗o年西北太平洋及南海热带气旋（TC）的活动特征并详细分析了造成2015年TC活动的大气环流特征。强El Ni〖AKn~D〗o年上半年TC生成偏多,台风活跃季（6—10月）TC生成偏少,登陆我国TC偏少,TC的生成位置较偏东南,并且台风路径多发生向东北的偏转。2015年生成的TC符合这一规律。El Ni〖AKn~D〗o成熟前赤道西太平洋存在大面积的西风异常,同时El Ni〖AKn~D〗o使得西北太平洋地区对流活动受到抑制,而副热带高压位置偏南,导致热带辐合带（ITCZ）位置偏南,这些因素综合作用导致了2015年台风季TC数量偏少。强El Ni〖AKn~D〗o年台风不但整体强度偏强,个体台风的强度也偏强,这是由于强El Ni〖AKn~D〗o年的副热带高压面积和强度偏小,有利于TC活动的加强。强El Ni〖AKn~D〗o年西北太平洋东南部生成的TC偏多,并且强度偏大;东北部生成的TC偏少。2015年的TC活动特征符合上述规律,生成于我国南海的TC个数少、强度偏小。从路径上来看,2015年台风路径多呈抛物线型,发生了向东北方向的转向,进入我国南海的TC明显偏少,这与副热带高压西伸脊点偏东,西北太平洋上空500 hPa异常的西北气流有关。 相似文献
6.
采用1949-2015年上海台风所提供的热带气旋资料、NCEP/NCAR全球再分析格点资料、国家气候中心提供的74项大气环流指数以及青藏高原积雪等资料,对7-9月登陆华南的热带气旋TC(不含热带低压)和台风TY(含台风及台风以上的热带气旋)的气候变化特征以及大尺度环流特征进行了分析,结果发现:7-9月登陆华南TC及TY频数均有微弱的上升趋势,且年际变化显著,但TC和TY年际变化和准十年波动变化并不总是一致,尤其是近10a来登陆华南的强台风有明显增加的趋势。7-9月登陆华南的TC占登陆中国的一半以上,并且有约3/4是来自西北太平洋生成的台风。从登陆华南TC的区间分布特征来看,以中路最多,西路次之,东路最少。亚洲季风偏弱、西太平洋副高偏西,登陆华南TY偏多,反之亦然。TC偏多(少)年,西太平洋副高偏强偏西(偏强偏东)。TC偏多年110oE以东引导气流出现的反气旋式和气旋式环流对较TC偏少年偏西,反气旋环流南部的东风异常一直延伸到华南地区东部,这样的东风引导气流异常有利于引导热带气旋登陆华南。另外,青藏高原东部和西部积雪偏多、华南气温偏高及西北太平洋海温异常偏暖的情况下也均有利于台风登陆华南。 相似文献
7.
《气象》2016,(9)
通过统计分析,本文研究了强El Nio年西北太平洋及南海热带气旋(TC)的活动特征并详细分析了造成2015年TC活动的大气环流特征。强El Nio年上半年TC生成偏多,台风活跃季(6—10月)TC生成偏少,登陆我国TC偏少,TC的生成位置较偏东南,并且台风路径多发生向东北的偏转。2015年生成的TC符合这一规律。El Nio成熟前赤道西太平洋存在大面积的西风异常,同时El Nio使得西北太平洋地区对流活动受到抑制,而副热带高压位置偏南,导致热带辐合带(ITCZ)位置偏南,这些因素综合作用导致了2015年台风季TC数量偏少。强El Nio年台风不但整体强度偏强,个体台风的强度也偏强,这是由于强El Nio年的副热带高压面积和强度偏小,有利于TC活动的加强。强El Nio年西北太平洋东南部生成的TC偏多,并且强度偏大;东北部生成的TC偏少。2015年的TC活动特征符合上述规律,生成于我国南海的TC个数少、强度偏小。从路径上来看,2015年台风路径多呈抛物线型,发生了向东北方向的转向,进入我国南海的TC明显偏少,这与副热带高压西伸脊点偏东,西北太平洋上空500 hPa异常的西北气流有关。 相似文献
8.
利用挪威卑尔根的全球大气-海洋-海冰耦合模式的300年气候态数值积分结果,结合观测资料,分析了夏季亚洲-太平洋涛动(APO)的年际变化对与西北太平洋热带气旋生成频数相关联的大尺度环流背景的影响。模式结果表明,当夏季APO异常偏强(弱)时,西太平洋副热带高压位置偏东(西)偏北(南),南亚高压位置偏北(南),西北太平洋低层大气异常辐合(辐散),高层大气异常辐散(辐合),对流活动加强(减弱)。这种环流背景条件有(不)利于西北太平洋热带气旋的发生发展,西北太平洋热带气旋频数因而偏多(少)。 相似文献
9.
西北太平洋热带气旋强度的年际变化特征及其大气环流背景场分析 总被引：4，自引：0，他引：4
利用上海台风研究所整理的1949—2007年CMA-STI热带气旋最佳路径资料,对1949—1975年、1976—1987年、1988—2007年这三个时段7—10月强度达到热带风暴及以上的热带气旋(简称为TC)强度的年际变化特征进行了分析比较,对TC活动强、弱年的大气环流背景场做了合成分析,并对各年TC强度与对应的西北太平洋副热带高压(简称为西太副高)、东亚副热带西风急流、热带东风急流、季风槽各特征指数做了相关分析,揭示了西北太平洋TC强度年际变化的机理。结果表明:(1) 这三个时段TC强度都有明显的年际变化特征;(2) 当TC强度偏大时,西太副高减弱东退,东亚副热带西风急流位置偏南,热带东风急流强度偏大,位置偏东,南半球冷空气活动偏强,越赤道气流偏强,季风槽较活跃、位置偏东,倾斜指数偏小;反之亦然;(3) 当越赤道气流偏强,季风槽较活跃时,有利于TC生成源区热带低压扰动的发生发展;而西太副高减弱东退,热带东风急流位置偏东时,TC生成源区850 hPa低空为正相对涡度异常,200 hPa高空为正散度异常。这样,低层水平辐合强、高层水平辐散强的配置使得该地区辐合上升运动、高层气流的辐散流出得以维持,且TC生成源区垂直风切变偏小,从而有利于TC的发生发展,TC强度偏大;反之亦然。 相似文献
10.
副热带高压脊线北跳日期预测及其与中国初台关系的研究 总被引：1，自引：0，他引：1
基于西太平洋副热带高压(副高)变化与西北太平洋热带气旋(TC)活动的关系,利用1980—2013年NCEP/NCAR 再分析日平均、月平均数据,计算副高脊线第一次北跳至25 °N或以北,30 °N以南的副高北跳日期序列。选取超前于副高北跳日期的三个气候变量为预测因子,建立了1980—2008年的副高北跳日期的多元线性回归方程模型,并由此预测2009—2013年的副高北跳日期。模型的整体模拟能力较好,但在某些年份的模拟结果与实际偏差较大;模型的回报预测结果能较好地描述2009—2013年副高北跳日期的年际变化特征。进一步利用美国联合台风预警中心数据,分析显示中国初台的登陆日期与副高北跳日期显著正相关;在多数年份中,副高北跳后的1~7天内,有西北太平洋TC登陆中国。通过对比副高北跳早晚年的大气环流场发现:副高早(晚)跳年,5—7月平均的西太平洋季风槽较常年偏东(较常年不明显),季风槽南侧纬向风辐合异常(纬向风辐合异常中心偏东、偏北);同期的副高中心较常年偏北(偏南)。这些环流异常可能有利于(不利于)西北太平洋TC生成并向中国方向移动,从而造成中国初台登陆日期容易偏早(偏晚)。 相似文献
11.
In this paper, we summarized the characteristics of tropical cyclones (TC) activity over the western North Pacific in 2004 and analyzed their causation. Compared with the normal, the annual frequency of TC in 2004 was slightly higher, tropical cyclones in 2004 had a longer life span and occurred in a concentrated period, the source of TC were situated eastward; in all tracks of TC, the recurvature tracks took up larger proportion, the landfall regions of TC were located northward, which concentrated from East China to Japan. The primary causes were revealed as follows. Firstly, the intensity and area of the western North Pacific subtropical high was stronger and larger than usual respectively, and its ridge was frequently in the form of cells and stretched northwestward. Secondly, the convergence of intertropical convergence zone (ITCZ) was reinforced and the convergence zone moved more eastward than average. Thirdly, the meridionality of the westerlies was larger than average and the cell-shaped ridge formed a saddle region, which is in favor of TC northward motion and recurature. 相似文献
12.
Based on the CMA tropical cyclone(TC) best track data as well as the reanalysis datasets from the NCEP/NCAR and NOAA, the variation characteristics of TC number from 1949 to 2013 over the western North Pacific(including the South China Sea) are examined. Notably, the time series of TC number exhibits a significant abrupt change from more to less around 1995. Comparative analysis indicates that the environmental factors necessary to TC formation also change significantly around the mid-1990 s. After 1995, accompanying with anomalous warm sea surface temperature(SST) in western equatorial Pacific, a La Nia-like pattern in tropical Pacific appears obviously. However,compared with the period before 1995, the vertical upward movement decreases, vertical shear of tropospheric zonal wind increases, and sea level pressure(SLP) rises, all of which are unfavorable to TC formation and work together to make TC number reduce markedly after 1995. Furthermore, when the typical interannual more and less TCs years are selected in the two separate stages before and after 1995, the relative importance of oceanic and atmospheric environments in interannual TC generation is also investigated respectively. The results imply that the SST over the tropical Pacific exerts relatively important influence on TC formation before 1995 whereas the atmospheric circulation plays a more prominent role in the generation of TC after 1995. 相似文献
13.
The Impact of Horizontal Resolution on the CNOP and on Its Identified Sensitive Areas for Tropical Cyclone Predictions 总被引：1，自引：0，他引：1
In this study,the impacts of horizontal resolution on the conditional nonlinear optimal perturbation (CNOP) and on its identified sensitive areas were investigated for tropical cyclone predictions.Three resolutions,30 km,60 km,and 120 km,were studied for three tropical cyclones,TC Mindulle (2004),TC Meari (2004),and TC Matsa (2005).Results show that CNOP may present different structures with different resolutions,and the major parts of CNOP become increasingly localized with increased horizontal resolution.CNOP produces spiral and baroclinic structures,which partially account for its rapid amplification.The differences in CNOP structures result in different sensitive areas,but there are common areas for the CNOP-identified sensitive areas at various resolutions,and the size of the common areas is different from case to case.Generally,the forecasts benefit more from the reduction of the initial errors in the sensitive areas identified using higher resolutions than those using lower resolutions.However,the largest improvement of the forecast can be obtained at the resolution that is not the highest for some cases.In addition,the sensitive areas identified at lower resolutions are also helpful for improving the forecast with a finer resolution,but the sensitive areas identified at the same resolution as the forecast would be the most beneficial. 相似文献
14.
西北太平洋迅速加强热带气旋的高空外流特征分析 总被引：1，自引：0，他引：1
选择西北太平洋1979—2012年的259个TC迅速加强 (RI) 阶段,利用IBTrACS的TC最佳路径观测资料、高分辨率的卫星观测资料 (GOES-10/12 CIMSS、Digital Typhoon),以及高分辨率的大气再分析资料 (ERA Interim),针对TC的高空外流通道类型、TC高空外流与周边环境场相互作用的类型进行分类分析。结果表明,迅速加强热带气旋的高空外流特征分为5类:单通道朝向赤道型 (SE)、单通道朝向极地型 (SP)、双通道分别朝向极地与赤道型 (D)、无急流通道型 (N)、通道转换型 (T)。SE、SP、D型的RI过程分为8种TC高空外流与周围环境场相互作用的基础类型,南亚高压、南半球的反气旋环流、位于TC东部与西部的中纬度高空槽（或TUTT）是影响TC高空外流的主要天气系统。 相似文献
15.
Three typhoon cases are selected to conduct a series of simulations that are initialized from sequential analyses. The results show that the forecast error in crucial area where a tropical cyclone (TC) interactes with the upstream trough is highly correlated to the track forecast error after the TC recurvature. Furthermore, sensitivity experiments confirm that the developments of the midlatitude downstream circulations and then the TC track after its recurvature are highly sensitive to the TC intensity and its location relative to the upstream trough, which can give an example or one way of sensitivity of the TC track to the TC-trough interaction. If the TC interacts with the upstream trough more strongly (e.g., the TC being intensified or getting closer to the upstream trough), the downstream circulations will be more meridional, thus the TC track will be more northerly and westerly; otherwise, the downstream circulations will be more zonal, and the TC track will be more southerly and easterly. 相似文献
16.
热带气旋路径偏折内在原因的动力分析 总被引：15，自引：4，他引：11
视热带气旋（以下简称ＴＣ）为半径等于Ｒ的圆形涡旋,对其水平运动方程作整个ＴＣ区域的平均,进而得到ＴＣ的移动方程。同时,视ＴＣ的移动轨迹为一特征弧线,导出了ＴＣ移动路径的曲率方程,并对ＴＣ的结构及其变化所引起的ＴＣ路径偏折规律进行了讨论。结果表明,ＴＣ的尺度大小、最大风速及春半径等的变化均能导致路径的偏折,此外,ＴＣ的非对称结构也是路径偏折的重要原因。 相似文献
17.
Based on the data(including radius of maximum winds) from the JTWC(Joint Typhoon Warning Center),the tropical cyclones(TCs) radii of the outermost closed isobar, TCs best tracks from Shanghai Typhoon Institute and the Black Body Temperature(TBB) of the Japanese geostationary meteorological satellite M1 TR IR1, and combining13 tropical cyclones which landed in China again after visiting the island of Taiwan during the period from 2001 to2010, we analyzed the relationship between the number of convective cores within TC circulation and the intensity of TC with the method of convective-stratiform technique(CST) and statistical and composite analysis. The results are shown as follows:(1) The number of convective cores in the entire TC circulation is well corresponding with the outer spiral rainbands and the density of convective cores in the inner core area increases(decreases) generally with increasing(decreasing) TC intensity. At the same time, the number of convective cores within the outer spiral rainbands is more than that within the inner core and does not change much with the TC intensity. However, the density of convective cores within the outer spiral rainbands is lower than that within the inner core.(2) The relationship described above is sensitive to landing location to some extent but not sensitive to the structure of TC.(3) The average value of TBB in the inner core area increases(decreases) generally with increasing(decreasing) of TC intensity, which is also sensitive to landing situation to some extent. At the same time, the average value of TBB within the outer spiral rainbands is close to that within the entire TC circulation, and both of them are more than that within the inner core. However, they do not reflect TC intensity change significantly.(4) The results of statistical composite based on convective cores and TBB are complementary with each other, so a combination of both can reflect the relationship between TC rainbands and TC intensity much better. 相似文献
18.
A South China Sea （SCS） local TC （SLT） is defined as a tropical cyclone （TC） that forms within the SCS region and can reach the grade of tropical storm （TS） or above. The statistical features of the SLTs from 1985 to 2007 are analyzed first. It is found that over the SCS about 68% of the TCs can develop into TSs. The SLT intensity is relatively weak and associated with its genesis latitude as well as its track. The SLT monthly number presents a seasonal variation with two peaks in May and July to September. Based on the daily heat flux data from the Woods Hole Oceanographic Institution_Objectively Analyzed air-sea Fluxes （WHOI_OAFlux） in the same period, the air-sea exchange during the process of generation and development of the SLT is studied. Results show that the heat fluxes released to the atmosphere increase significantly day by day before cyclogenesis. The ocean to the south to the TC center provides the main energy. Along with the development of SLT, the regions with large heat fluxes spread clockwise to the north of TC, which reflects the energy dispersion property of vortex Rossby waves in the periphery of the TC. Once the SLT forms the heat fluxes are not intensified as much. During the whole process, the net heat, latent heat and sensible heat flux display a similar evolution, while the latent heat flux makes a main contribution to the net heat flux. The maximum air-sea heat exchange always occurs at the left side of the TC moving direction, which may reflect the influence of the SCS summer monsoon on TC structure. 相似文献
19.
Based on the Joint Typhoon Warning Center (JTWC) best-track dataset between 1965 and 2009 and the characteristic parameters including tropical cyclone (TC) position, intensity, path length and direction, a method for objective classification of the Northwestern Pacific tropical cyclone tracks is established by using K-means Clustering. The TC lifespan, energy, active season and landfall probability of seven clusters of tropical cyclone tracks are comparatively analyzed. The characteristics of these parameters are quite different among different tropical cyclone track clusters. From the trend of the past two decades, the frequency of the western recurving cluster (accounting for 21.3% of the total) increased, and the lifespan elongated slightly, which differs from the other clusters. The annual variation of the Power Dissipation Index (PDI) of most clusters mainly depended on the TC intensity and frequency. However, the annual variation of the PDI in the northwestern moving then recurving cluster and the pelagic west-northwest moving cluster mainly depended on the frequency. 相似文献
20.
一个与卫星TBB相匹配的人造台风构造方案 总被引：6，自引：4，他引：2
在台风数值预报中需要重点考虑的问题是初值条件,特别是人造台风的构造(typhoon bogusing)在当中起着重要作用.一个新的人造台风构造方案被提出,该方案在初值中引入了较真实的台风结构,尝试利用卫星探测TBB资料来改进人造台风中对流加热的分布,确定与卫星TBB协调一致的人造台风径向环流场,这能改善风-压平衡,使得模式对强加入的人造台风更协调. 相似文献