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该文给出了热带气旋暖心垂直倾斜度参数FTC-VGP(TC vertical gradient parameter) 的定义。使用卫星微波遥感的温度垂直分布以及热带气旋最佳路径数据等资料,对2009—2011年典型热带气旋的暖心垂直倾斜度进行计算,并研究其与气旋强度变化的关系。结果表明:暖心垂直倾斜度参数FTC-VGP变化与气旋自身强度变化有较好的对应性,该参数的变化能够明显地指示气旋强度增强、减弱以及强度突变, 能够指示环境场变化 (冷空气侵入) 等;其与气旋强度变化的周期不同,在强度增强或减弱阶段,倾斜度参数是经过快速适应性调整才完成了对热带气旋变化过程的贡献。因此,FTC-VGP参数的计算和研究结果实现了对于热带气旋内部三维结构特征的定量描述,可以准确把握热带气旋强度和变化趋势,并对热带气旋的监测、预报具有一定业务参考价值。 相似文献
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基于改进的累积气旋能量指数评估西北太平洋TC活动与ENSO的关系 总被引：1，自引：1，他引：0
采用1977—2008年日本气象厅(JMA)TC最佳路径集资料和美国气候预测中心(CPC)的ENSO资料,设计了一个考虑热带气旋(TC)尺度信息的累积气旋能量指数(SACE),据此分析了西北太平洋TC活动与ENSO之间的关系。结果表明:相比于不考虑尺度效应的ACE,引入TC尺度信息的SACE增加了较大强度、较大尺度TC活动水平的权重,能够更加准确地刻画TC强度及其影响,其与Ni1o指数的相关性进一步增强。SACE能够更好地表征西北太平洋TC活动与ENSO年际变化的关系,其对ENSO位相的依赖性相对于ACE更为敏感,是一个能更好预测ENSO状态的因子。TC强度、生命史、频数以及尺度均对SACE有一定的贡献,但生命史的贡献最大,这一方面说明ENSO主要通过调制TC生命史来影响SACE,另一方面也说明相对于强度、频数和尺度而言,TC生命史更能影响SACE中的ENSO信号。 相似文献
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热带气旋(TC)的结构(含形态)与强度及其变化关系密切,著名的Dvorak定强技术即为TC形态(水平)变化与强度关系的生动描述,近年来水平尺度与强度变化的关系也渐受关注。然而,至今未涉及整体形态(即体积)与TC强度变化的关系。利用欧洲中期数值预报中心(ECMWF)0.25 °的ERA-Interim再分析资料,统计并初步分析了2006—2015年西北太平洋TC的外围水平尺度和“体积”的特征及其与强度的可能关系:水平尺度与TC强度的相关性总体较弱;而TC“体积”与强度的相关性更显著,且TC“体积”随强度增强而增大的关系适用于所有强度级别;此外,TC垂直尺度(正涡度区伸展高度)与强度也有一定的正相关,且在TC较弱时(台风强度以下)更显著。伴随较弱TC增强的主要是垂直尺度的增大,当TC达到台风强度后,与TC强度继续增强相伴随的主要是水平尺度的增大。TC“体积”能较好地综合表征水平尺度和垂直尺度与TC强度变化的关系,借助TC“体积”对TC强度预报有一定的参考价值。 相似文献
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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
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In order to investigate whether adaptive observations can improve tropical cyclone （TC） intensity forecasts,observing system simulation experiments （OSSEs） were conducted for 20 TC cases originating in the western North Pacific during the 2010 season according to the conditional nonlinear optimal perturbation （CNOP） sensitivity,using the fifth version of the PSU/NCAR mesoscale model （MM5） and its 3DVAR assimilation system.A new intensity index was defined as the sum of the number of grid points within an allocated square centered at the corresponding forecast TC central position,that satisfy constraints associated with the Sea Level Pressure （SLP）,near-surface horizontal wind speed,and accumulated convective precipitation.The higher the index value is,the more intense the TC is.The impacts of the CNOP sensitivity on the intensity forecast were then estimated.The OSSE results showed that for 15 of the 20 cases there were improvements,with reductions of forecast errors in the range of 0.12％-8.59％,which were much less than in track forecasts.The indication,therefore,is that the CNOP sensitivity has a generally positive effect on TC intensity forecasts,but only to a certain degree.We conclude that factors such as the use of a coupled model,or better initialization of the TC vortex,are more important for an accurate TC intensity forecast. 相似文献
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以三个西北太平洋热带气旋（TC）为例,利用WRF（Weather Research and Forecasting）模式进行了一系列海表温度（SST）敏感性数值试验,揭示了西北太平洋SST增暖对TC的强度、尺度及潜在破坏力的影响及其机理。结果表明,在距TC中心100 km以内区域的SST升高有利于TC强度增加,但会减小TC内核尺度;而在距TC中心100 km以外的SST升高并不会使TC强度明显增加甚至使TC强度减弱,但同时会增加TC内核尺度。伴随着低层向眼墙的入流,升高的外区SST会使TC区表层的大气温度和湿度升高,造成眼墙附近海气温差和湿度差及向内的气压梯度力减小,进而减少进入TC眼墙内的感热和潜热,不利于TC增强,但有利于眼墙向外移动,使TC内核尺度增加。内区SST升高与外区SST升高对TC强度及尺度变化的作用机理相反。因此,当TC移过冷或暖洋面时,TC的强度和尺度的变化不仅取决于局地洋面的冷或暖状况,还取决于TC内区和外区SST的差异。由于TC内区和外区SST对TC强度和内核尺度的不同作用,可能存在一个临界范围,当暖池范围在这个临界范围之内时TC潜在破坏力随暖池范围的扩大而增大,但当暖池范围超过这个临界范围时TC潜在破坏力便不会随着暖池范围的继续扩大而增大,甚至会有所减小。 相似文献
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Summary Current understanding of tropical cyclone (TC) structure and intensity changes has been reviewed in this article. Recent studies in this area tend to focus on two issues: (1) what factors determine the maximum potential intensity (MPI) that a TC can achieve given the thermodynamic state of the atmosphere and the ocean? and (2) what factors prevent the TCs from reaching their MPIs? Although the MPI theories appear mature, recent studies of the so-called superintensity pose a potential challenge. It is notable that the maximum intensities reached by real TCs in all ocean basins are generally lower than those inferred from the theoretical MPI, indicating that internal dynamics and external forcing from environmental flow prohibit the TC intensification most and limit the TC intensity. It remains to be seen whether such factors can be included in improved MPI approaches.Among many limiting factors, the unfavorable environmental conditions, especially the vertical shear-induced asymmetry in the inner core region and the cooling of sea surface due to the oceanic upwelling under the eyewall region, have been postulated as the primary impediment to a TC reaching its MPI. However, recent studies show that the mesoscale processes, which create asymmetries in the TC core region, play key roles in TC structure and intensity changes. These include the inner and outer spiral rainbands, convectively coupled vortex Rossby waves, eyewall cycles, and embedded mesovortices in TC circulation. It is also through these inner core processes that the external environmental flow affects the TC structure and intensity changes. It is proposed that future research be focused on improving the understanding of how the eyewall processes respond to all external forcing and affect the TC structure and intensity changes. Rapid TC intensity changes (both strengthening and weakening) are believed to involve complex interactions between different scales and to be worthy of future research.The boundary-layer processes are crucial to TC formation, maintenance, and decaying. Significant progress has been made to deduce the drag coefficient on high wind conditions from the measurements of boundary layer winds in the vicinity of hurricane eyewalls by Global Positioning System (GPS) dropsondes. This breakthrough can lead to reduction of the uncertainties in the calculation of surface fluxes, thus improving TC intensity forecast by numerical weather prediction models. 相似文献
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探讨了一种利用海岛自动站、石油平台站、海洋气象浮标观测站、船载自动气象站等在内的海基观测资料来改进南海热带气旋强度分析的客观估计方案,并利用该方案对近几年（2013—2016年）出现在南海海域的18个热带气旋强度进行了分析。结果表明：该方案的估计误差与基于卫星遥感资料分析得到的结果水平相当,其估计效果与热带气旋的自身强度和有效样本数量有关,同时是否有观测样本位于热带气旋最大风速半径内也会影响估计的准确性。在传统基于卫星遥感资料对热带气旋强度主客观分析出现不一致时,利用海基观测来估计台风的强度可以作为一种补充方案来提高强度分析的可靠性。 相似文献
10.
The Dynamic and Thermodynamic Effects of Relative and Absolute Sea Surface Temperature on Tropical Cyclone Intensity 总被引：1，自引：0，他引：1 
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下载免费PDF全文 Several numerical experiments were performed to investigate the dynamic and thermodynamic effects of sea surface temperature(SST) on tropical cyclone(TC) intensity.The results reveal that the relative SST within a radius of 2-3 times the radius of maximum wind contributes positively and greatly to TC intensity,while the remote SST far away from the TC center could reduce storm intensity.The change of air-sea temperature and moisture differences may be the reason why TC intensity is more sensitive to the relative rather than the absolute SST.As the inflow air moves toward the eyewall,warmer(colder) remote SST can gradually increase(decrease) the underlying surface air temperature and moisture,and thus decrease(increase) the air-sea temperature and moisture differences,which lead to less(more) energy fluxes entering the eyewall and then decrease(increase) the TC intensity and make it less sensitive to the absolute SST change.Finally,with all the related dynamic and thermodynamic processes being taken into account,a schematic diagram for the effects of relative SST and absolute SST on TC intensity is proposed. 相似文献
11.
The role of sea surface temperature (SST) forcing in the development and predictability of tropical cyclone (TC) intensity is examined using a large set of idealized numerical experiments in the Weather Research and Forecasting (WRF) model. The results indicate that the onset time of rapid intensification of TC gradually decreases, and the peak intensity of TC gradually increases, with the increased magnitude of SST. The predictability limits of the maximum 10 m wind speed (MWS) and minimum sea level pressure (MSLP) are ~72 and ~84 hours, respectively. Comparisons of the analyses of variance for different simulation time confirm that the MWS and MSLP have strong signal-to-noise ratios (SNR) from 0-72 hours and a marked decrease beyond 72 hours. For the horizontal and vertical structures of wind speed, noticeable decreases in the magnitude of SNR can be seen as the simulation time increases, similar to that of the SLP or perturbation pressure. These results indicate that the SST as an external forcing signal plays an important role in TC intensity for up to 72 hours, and it is significantly weakened if the simulation time exceeds the predictability limits of TC intensity. 相似文献
12.
It has been challenging to project the tropical cyclone(TC) intensity,structure and destructive potential changes in a warming climate.Here,we compare the sensitivities of TC intensity,size and destructive potential to sea surface warming with and without a pre-storm atmospheric adjustment to an idealized state of Radiative-Convective Equilibrium(RCE).Without RCE,we find large responses of TC intensity,size and destructive potential to sea surface temperature(SST) changes,which is in line with some previous studies.However,in an environment under RCE,the TC size is almost insensitive to SST changes,and the sensitivity of intensity is also much reduced to 3%?C-1–4%?C-1.Without the pre-storm RCE adjustment,the mean destructive potential measured by the integrated power dissipation increases by about 25%?C-1 during the mature stage.However,in an environment under RCE,the sensitivity of destructive potential to sea surface warming does not change significantly.Further analyses show that the reduced response of TC intensity and size to sea surface warming under RCE can be explained by the reduced thermodynamic disequilibrium between the air boundary layer and the sea surface due to the RCE adjustment.When conducting regional-scale sea surface warming experiments for TC case studies,without any RCE adjustment the TC response is likely to be unrealistically exaggerated.The TC intensity–temperature sensitivity under RCE is very similar to those found in coupled climate model simulations.This suggests global mean intensity projections under climate change can be understood in terms of a thermodynamic response to temperature with only a minor contribution from any changes in large-scale dynamics. 相似文献
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热带气旋的登陆及其与中纬度环流系统相互作用的研究 总被引：36，自引：6，他引：36
热带气旋的主要灾害往往在登陆前后造成，登陆问题是当今热带气旋 研究的重点。热带气旋与中纬度环流系统相互作用，不仅影响热带气旋的结构和强度变化， 也对中纬度地区天气产生重大影响。西风槽强度的变化可使热带气旋的降水突然 增幅３０％。环境场的急剧调整常引起热带气旋运动突变，在弱环境场中，热带气旋的异常运 动与非对称结构关系紧密。中纬度系统对热带气旋的非对称结构有重要影响。另一方面，热 带气旋向极移动过程中携带了大量可供中纬度地区降水的水汽，在气旋性切变的环境场中， 热带气旋还向环境场输送能量，并激发和增强中纬度气旋性环流系统的发展，触发严重的灾 害性天气。热带气旋有时也会截断低纬向中纬度的水汽输送及中纬度波动的能量频散，９５％ 左右的南海热带气旋对梅雨有显著影响，其中约８６％的热带气旋会导致梅雨减弱中断甚至结 束。 相似文献
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利用日本MTSAT (multi-functional transport satellite) 红外亮温资料,提取热带气旋云团中云顶较高、对流较旺盛的深对流信息,根据提取的对流核数量、对流核距热带气旋中心距离、对流核亮温极值等信息表征热带气旋强弱,初步建立了热带气旋强度估测模型;并根据该估算模型的误差分布对强度 (用最大风速表示) 大于40 m·s-1和小于18 m·s-1的样本结果进行了线性修正,修正后的结果与中国气象局《热带气旋年鉴》热带气旋最佳路径资料比较得到非独立样本和独立样本的强度平均绝对误差分别为5.5 m·s-1和5.9 m·s-1, 均方根误差分别为6.9 m·s-1和7.7 m·s-1;对于热带低压、强台风及以上的估计平均绝对误差分别降至4.9,4.7 m·s-1,准确度较好。试验表明:利用热带气旋云团中的对流核数量、分布、冷暖与其强度建立的统计关系模型是可行的,该算法的估算精度与Dvorak方法、AMSU (advanced microwave sounding unit) 定强算法相当。 相似文献
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A western North Pacific tropical cyclone (TC) intensity prediction scheme (WIPS) is developed based
on TC samples from 1996 to 2002 using the stepwise regression technique, with the western North Pacific
divided into three sub-regions: the region near the coast of East China (ECR), the South China Sea region
(SCR), and the far oceanic region (FOR). Only the TCs with maximum sustained surface wind speed greater
than 17.2 m s-1 are used in the scheme. Potential predictors include the climatology and persistence factors,
synoptic environmental conditions, potential intensity of a TC and proximity of a TC to land. Variances
explained by the selected predictors suggest that the potential intensity of a TC and the proximity of a TC
to land are significant in almost all the forecast equations. Other important predictors include vertical wind
shear in ECR, 500-hPa geopotential height anomaly at the TC center, zonal component of TC translation
speed in SCR, intensity change of TC 12 or 24 h prior to initial time, and the longitude of TC center in
FOR.
Independent tests are carried out for TCs in 4 yr (2004-2007), with mean absolute errors of the maximum
surface wind being 3.0, 5.0, 6.5, 7.3, 7.6, and 7.9 m s-1 for 12- to 72-h predictions at 12-h intervals,
respectively. Positive skills are obtained at all leading time levels as compared to the climatology and
persistence prediction scheme, and the large skill scores (near or over 20%) after 36 h imply that WIPS
performs especially better at longer leading times. Furthermore, it is found that the amendment in TC
track prediction and real-time model analysis can significantly improve the performance of WIPS in the
SCR and ECR. Future improvements will focus on applying the scheme for weakening TCs and those near
the coastal regions. 相似文献
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Du Duc Tien Thanh Ngo-Duc Hoang Thi Mai Chanh Kieu 《Meteorology and Atmospheric Physics》2013,122(1-2):55-64
This study examines the dependence of the tropical cyclone (TC) intensity errors on the track errors in the Weather Research and Forecasting (WRF-ARW) model. By using the National Centers for Environmental Prediction global final analysis as the initial and boundary conditions for cloud-resolving simulations of TC cases that have small track errors, it is found that the 2- and 3-day intensity errors in the North Atlantic basin can be reduced to 15 and 19 % when the track errors decrease to 55 and 76 %, respectively, whereas the 1-day intensity error shows no significant reduction despite more than 30 % decrease of the 1-day track error. For the North-Western Pacific basin, the percentage of intensity reduction is somewhat similar with the 2- and 3-day intensity errors improved by about 15 and 19 %, respectively. This suggests that future improvement of the TC track forecast skill in the WRF-ARW model will be beneficial to the intensity forecast. However, the substantially smaller percentages of intensity improvement than those of the track error improvement indicate that ambient environment tends to play a less important role in determining the TC intensity as compared to other factors related to the vortex initialization or physics representations in the WRF-ARW model. 相似文献
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热带气旋结构和强度变化研究进展 总被引：2，自引：0，他引：2
热带气旋结构和强度变化的物理过程和影响因子十分复杂,其登陆过程中海-陆-气三者之间的复杂作用常使其结构和强度发生突变,给热带气旋预报带来较大困难。近年来外场科学试验及数值模拟等科学方法都取得较大改进,在此基础上对热带气旋结构和强度研究取得了新的进展,如热带气旋强度突变及不同下垫面对热带气旋强度变化的影响等。但对热带气旋非对称结构对其强度的影响及热带气旋内部结构变化与其强度之间的联系等问题的研究仍不全面。本文通过查阅国内外相关研究文献,从环境气流、下垫面及内部结构3个主要方面,总结影响热带气旋结构和强度变化的主要因子,以期为改进热带气旋结构和强度的预报方法提供有意义的理论依据。 相似文献
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A Statistical Analysis on the E ect of Vertical Wind Shear on Tropical Cyclone Development 下载免费PDF全文
下载免费PDF全文 Using tropical cyclone (TC) best track and intensity of the western North Pacific data from the Joint TyphoonWarning Center (JTWC) of the United States and the NCEP/NCAR reanalysis data for the period of 1992-2002, the effects of vertical wind shear on TC intensity are examined. The samples were limited to the westward or northwestward moving TCs between 5°N and 20°N in order to minimize thermodynamic effects. It is found that the effect of vertical wind shear between 200 and 500 hPa on TC intensity change is larger than that of the shear between 500 and 850 hPa, while similar to that of the shear between 200 and 850 hPa. Vertical wind shear may have a threshold value, which tends to decrease as TC intensifies. As the intensifying rate of TC weakens, the average shear increases. The large shear has the obvious trend of inhibiting TC development. The average shear of TC which can develop into typhoon (tropical depression or tropical storm) is below 7 m s-1 (above 8 m s-1). 相似文献