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1.
Focusing on the role of initial condition uncertainty, we use WRF initial perturbation ensemble forecasts to investigate the uncertainty in intensity forecasts of Tropical Cyclone(TC) Rammasun(1409), which is the strongest TC to have made landfall in China during the past 50 years. Forecast results indicate that initial condition uncertainty leads to TC forecast uncertainty, particularly for TC intensity. This uncertainty increases with forecast time, with a more rapid and significant increase a... 相似文献
2.
利用中尺度模式HWRF(Hurricane Weather Research and Forecast System)模拟双热带气旋\"狮子山\"(2010)与\"南川\"(2010)涡旋合并过程,并通过强度敏感性试验揭示两涡旋强度对合并过程的影响。分析表明:在两者的合并过程中,\"狮子山\"涡旋强度明显大于\"南川\";\"狮子山\"涡旋对\"南川\"涡旋具有更大的\"吸引\"效应,两者西侧呈相对强的能量、水汽\"连体\"通道。HWRF能够较好的模拟出双热带气旋\"狮子山\"与\"南川\"的强度、移动路径,尤其是两涡旋的合并过程。进一步分析控制试验双热带气旋水平与垂直结构揭示出两涡旋\"互旋\"过程中,\"弱涡旋\"并入\"强涡旋\"相互影响特征。有关\"狮子山\"与\"南川\"强度的敏感试验亦表明,两者各自涡旋强度\"合并方向\"具有关键影响。在敏感性试验中,改变涡旋强度后两者路径亦存在\"互旋\"现象,但与控制试验两涡旋\"合并方向\"相反,即敏感性试验热带气旋\"狮子山\"涡旋削弱,而\"南川\"涡旋强度相对增强,导致原涡旋西侧水汽、能量输送连体通道明显削弱,同时由于\"南川\"涡旋的强度强于\"狮子山\",两者东侧水汽、能量输送通道亦加强,导致\"南川\"涡旋对\"狮子山\"的涡旋存在\"吸引\"效应。\"狮子山\"涡旋残留云带一部分合并入\"南川\",一部分则随西南气流进入台风\"圆规\"。 相似文献
3.
采用准地转的正压模式, 研究了无非绝热加热时地形和边界层摩擦对登陆热带气旋路径和强度的影响.结果表明: 地形作用对登陆热带气旋西北移动路径的影响比较明显, 而对登陆热带气旋强度的影响不明显; 边界层摩擦可以通过改变热带气旋X方向上和Y方向上的移动速度以及改变热带气旋水平环流结构对登陆热带气旋西北移动路径产生一定的影响, 边界层摩擦对登陆热带气旋强度的影响非常明显, 其中摩擦是造成登陆热带气旋强度迅速减弱的一个重要因素. 相似文献
4.
热带气旋强度与结构研究新进展 总被引：13，自引：6，他引：13
主要回顾热带气旋(TC)强度与结构变化的研究发展近况。以往热带气旋的理论研究认为在给定的大气和海洋热状况下,存在着一个TC所能达到的最大可能强度(MPI)。但实际上,海洋生成的热带气旋达到的最大强度普遍要比由MPI理论计算得到最大强度要低。近几年的研究表明,存在着内部和外部的不利因子通过对TC结构的改变来阻碍其加强,从而限制TC的强度。以往认为在诸多因子中,垂直风切变产生的内核区非对称结构与眼墙区下方海水上涌造成的海面冷却是制约TC达到MPI的主要因子。最新的研究进一步指出,产生TC非对称性的中尺度过程对其强度与结构的变化至关重要。中尺度过程包含有对流耦合的涡旋Rossby波、内外圈螺旋雨带、嵌于TC环流内的中尺度涡旋。外部的环境气流也是通过这些眼墙的中尺度过程影响到TC的强度与结构变化。 相似文献
5.
The boundary layer structure and related heavy rainfall of Typhoon Fitow(2013), which made landfall in Zhejiang Province, China, are studied using the Advanced Research version of the Weather Research and Forecasting model, with a focus on the sensitivity of the simulation to the planetary boundary layer parameterization. Two groups of experiments—one with the same surface layer scheme and including the Yonsei University(YSU), Mellor–Yamada–Nakanishi–Niino Level 2.5,and Bougeault and Lacarrere schemes; and the other with different surface layer schemes and including the Mellor–Yamada–Janjic′ and Quasi-Normal Scale Elimination schemes—are investigated. For the convenience of comparative analysis, the simulation with the YSU scheme is chosen as the control run because this scheme successfully reproduces the track, intensity and rainfall as a whole. The maximum deviations in the peak tangential and peak radial winds may account for 11% and 33%of those produced in the control run, respectively. Further diagnosis indicates that the vertical diffusivity is much larger in the first group, resulting in weaker vertical shear of the tangential and radial winds in the boundary layer and a deeper inflow layer therein. The precipitation discrepancies are related to the simulated track deflection and the differences in the simulated low-level convergent flow among all tests. Furthermore, the first group more efficiently transfers moisture and energy and produces a stronger ascending motion than the second, contributing to a deeper moist layer, stronger convection and greater precipitation. 相似文献
6.
1. IntroductionMuch attention has been paid to the role playedby diabatic heating in the genesis and intensificationof tropical cyclone (TC). Based on a two-dimensionalprimitive equation model, Li (1984) proposed that theevolution of TC should be different if the maximumheating appears at different height. Yang et al. (1995)found that abrupt intensification of TC at the mid-latitudes is closely related to the vertical structure ofconvective heating. May and Holland (1998) suggestedthat the… 相似文献
7.
CAI Ninghao XU Xin SONG Lili BAI Lin MING Jie WANG Yuan 《Acta Meteorologica Sinica》2014,28(1):127-138
This work studies the impact of the vertical shear of gradient wind （VSGW） in the free atmosphere on the tropical cyclone boundary layer （TCBL）. A new TCBL model is established, which relies on five- force balance including the pressure gradient force, Coriolis force, centrifugal force, turbulent friction, and inertial deviation force. This model is then employed to idealize tropical cyclones （TCs） produced by DeMaria＇s model, under different VSGW conditions （non-VSGW, positive VSGW, negative VSGW, and VSGW increase/decrease along the radial direction）. The results show that the free-atmosphere VSGW is particularly important to the intensity of TC. For negative VSGW, the total horizontal velocity in the TCBL is somewhat suppressed. However, with the maximum radial inflow displaced upward and outward, the radial velocity notably intensifies. Consequently, the convergence is enhanced throughout the TCBL, giving rise to a stronger vertical pumping at the TCBL top. In contrast, for positive VSGW, the radial inflow is significantly suppressed, even with divergent outflow in the middle-upper TCBL. For varying VSGW along the radial direction, the results indicate that the sign and value of VSGW is more important than its radial distribution, and the negative VSGW induces stronger convergence and Ekman pumping in the TCBL. which favors the formation and intensification of TC. 相似文献
8.
MA Zhanhong FEI Jianfang HUANG Xiaogang CHENG Xiaoping LIU Lei 《Acta Meteorologica Sinica》2013,27(6):910-922
In this study, the interaction between the tropical cyclone（TC） and the underlying ocean is reproduced by using a coupled atmosphere-ocean model. Based on the simulation results, characteristics of the TC boundary layer depth are investigated in terms of three commonly used definitions, i.e., the height of the mixed layer depth（HVTH）, the height of the maximum tangential winds（HTAN）, and the inflow layer depth（HRAD）. The symmetric height of the boundary layer is shown to be cut down by the ocean response, with the decrease of HVTH slightly smaller than that of HTAN and HRAD. The ocean feedback also leads to evident changes in asymmetric features of the boundary layer depth. The HVTH in the right rear of the TC is significantly diminished due to presence of the cold wake, while the changes of HVTH in other regions are rather small. The decreased surface virtual potential temperature by the cold wake is identified to be dominant in the asymmetric changes in HVTH. The impacts of ocean response on the asymmetric distributions of HTAN are nonetheless not distinct, which is attributed to the highly axisymmetric property of tangential winds. The HRAD possesses remarkable asymmetric features and the inflow layer does not exist in all regions, an indication of the inadequacy of the definition based on symmetric inflow layer depth. Under influences of the cold wake, the peak inflow area rotates counterclockwise distinctly. As a consequence, the HRAD becomes deeper in the east while shallower in the west of the TC. 相似文献
9.
Under two types of initial tropical cyclone structures that are characterized by high and low vorticity zones, four sets of numerical experiments have been performed to investigate the interaction of a tropical cyclone with an adjacent mesoscale vortex (MSV) and its impact on the tropical cyclone intensity change,using a quasi-geostrophic barotropic vorticity equation model with a horizontal resolution of 0.5 km. The results suggest that the interaction of a tropical cyclone characterized by a high vorticity zonal structure and an MSV would result in an intensification of the cyclone. Its central pressure decreases by more than 14 hPa. In the process of tile interaction, the west and middle segments of the high vorticity zone evolve into two peripheral spiral bands of the tropical cyclone, and the merging of the east segment and the inward propagating MSV forms a new vorticity accumulation area, wherein the maximum vorticity is remarkably greater than that in the center of the initial tropical cyclone circulation. It is this process of merging and strengthening that causes a greater pressure decrease in the center of the tropical cyclone. This process is also more complicated than those that have been studied in the past, which indicated that only the inward transfer of vorticity of the MSV can result in the strengthening of the tropical cyclone. 相似文献
10.
A limited-area primitive equation model is used to study the role of the β-effect and a uniform current on tropical cyclone (TC) intensity.It is found that TC intensity is reduced in a non-quiescent environment compared with the case of no uniform current.On an f-plane,the rate of intensification of a tropical cyclone is larger than that of the uniform flow.A TC on a β-plane intensifies slower than one on an f-plane.The main physical characteristic that distinguishes the experiments is the asymmetric thermodynamic (including convective) and dynamic structures present when either a uniform flow or β-effect is introduced.But a fairly symmetric TC structure is simulated on an f-plane.The magnitude of the warm core and the associated subsidence are found to be responsible for such simulated intensity changes.On an f-plane,the convection tends to be symmetric,which results in strong upper-level convergence near the center and hence strong forced subsidence and a very warm core.On the other hand,horizontal advection of temperature cancels part of the adiabatic heating and results in less warming of the core,and hence the TC is not as intense.This advective process is due to the tilt of the vortex as a result of the β-effect.A similar situation occurs in the presence of a uniform flow.Thus,the asymmetric horizontal advection of temperature plays an important role in the temperature distribution.Dynamically,the asymmetric angular momentum (AM) flux is very small on an f-plane throughout the troposphere.However,the total AM exports at the upper levels for a TC either on aβ-plane or with a uniform flow environment are larger because of an increase of the asymmetric as well as symmetric AM export on the plane at radii ＞450 km,and hence there is a lesser intensification. 相似文献
11.
用中国气象局整编的1949-2003年共55年的《台风年鉴》和《热带气旋年鉴》资料,依据平均值与标准差的数学涵义,给出了TC突然增强、缓慢增强、强度稳定、缓慢减弱和突然减弱的标准,分析了西北太平洋热带气旋(TC)强度变化的年代际、年际、月际、日变化和区域分布的基本特征。结果表明:(1)1960年代以前,T℃的年平均增强或减弱幅度较小。(2)在TC出现较为频繁的夏秋季节,8月份TC强度变幅较小。TC在14时(北京时,下同)最易发展,20时最易减弱;08时TC增强速度最快,02时最慢;02时TC减弱速度最快, 20时最慢。(3)TC频数和增强TC频数的高值区位于海南岛以东的南海北部中国近海区域和菲律宾以东洋面,减弱类TC频数极值区在吕宋岛及其东部海域、海南岛以西的北部湾、广东沿岸。(4)TC突然增强不出现在30°N以北的中高纬地区和0—5°N的低纬地区。TC突然减弱多出现在125°E以西的中国近海大范围海域,在0～5°N的低纬地区基本不出现。 相似文献
12.
A western North Pacific tropical cyclone (TC) intensity prediction scheme (WIPS) is developed basedon TC samples from 1996 to 2002 using the stepwise regression technique, with the western North Pacificdivided 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 greaterthan 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. Variancesexplained by the selected predictors suggest that the potential intensity of a TC and the proximity of a TCto land are significant in almost all the forecast equations. Other important predictors include vertical windshear in ECR, 500-hPa geopotential height anomaly at the TC center, zonal component of TC translationspeed in SCR, intensity change of TC 12 or 24 h prior to initial time, and the longitude of TC center inFOR.Independent tests are carried out for TCs in 4 yr (2004-2007), with mean absolute errors of the maximumsurface 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 andpersistence prediction scheme, and the large skill scores (near or over 20%) after 36 h imply that WIPSperforms especially better at longer leading times. Furthermore, it is found that the amendment in TCtrack prediction and real-time model analysis can significantly improve the performance of WIPS in theSCR and ECR. Future improvements will focus on applying the scheme for weakening TCs and those nearthe coastal regions. 相似文献
13.
用数字云图确定热带气旋强度的原理和方法 总被引：5，自引：1，他引：5
本文采用数字云图资料，分析热带气旋强度与热带气旋中云系结构的关系，提出了云系结构紧密度因子的概念并用云带旋转的圈数表示热带气旋强度的方法。本文对原有关于热带气旋中云系结构的某些因子的取值作了适当调整， 改进了用增强红外云图确定热带气旋强度的方法。 经过对2446组样本的拟合，热带气旋强度最大风速估计值的平均绝对误差为2.48 m/s。本方法可以实现人机交互，能更客观地作出定量估计。对1993年12个热带气旋检验，最大风速平均绝对误差为2.31 m/s。 相似文献
14.
西北太平洋热带气旋强度统计释用预报方法研究 总被引：4，自引：1，他引：4
为了提高西北太平洋地区热带气旋（TC）强度预报准确率,在气候持续预报方法基础上,考虑气候持续性因子、天气因子、卫星资料因子,以TC强度变化为预报对象,运用逐步回归统计方法,建立西北太平洋地区24、48、72小时TC强度预报方程。通过不同的分海区试验（远海区域、华东近海、华南近海）,证明回归结果较好。逐一分析选入因子发现：气候持续性因子在方程中相当重要;同时对远海区域和华东近海而言,海温影响也不容忽视,对华南近海而言,反映动力强迫作用的因素也较为重要。卫星资料的加入,对回归结果略有改进。用“刀切法”作独立样本检验,与气候持续法比较,预报误差明显减小。 相似文献
15.
Wei TIAN Ping SONG Yuanyuan CHEN Yonghong ZHANG Liguang WU Haikun ZHAO Kenny Thiam Choy LIM KAM SIAN Chunyi XIANG 《大气科学进展》2025,89(1):111-128
热带气旋（TC）是最严重的自然灾害之一,准确的热带气旋活动预测是预防和减轻灾害的关键。近年来,热带气旋轨迹预测取得重大进展,但强度预测能力明显滞后。目前,热带气旋强度预测的研究以大气再分析数据为研究对象,通过深层学习挖掘热带气旋相关环境因素与强度之间的关系。然而,再分析数据在本质上是非实时的,难以满足业务预报应用需求。强对流云团对称化程度和对流强度,将偏角方差与卫星图像融合来构建热带气旋对流结构与强度的相关性。针对热带气旋复杂的动态过程,本文使用卷积神经网络（CNN）学习其时序特征和空间特征。在实时强度估计这一主任务下,多任务学习起到隐式时序增强作用。模型设计了滚动策略,旨在缓解长期依赖衰减问题,提升短期强度预测的精度。考虑到多个任务之间的相关性,对12小时和24小时的损失函数进行了修正。在西北太平洋TC样本上的实验结果表明,TC-Rolling模型在6小时、12小时和24小时强度预测上的均方根误差（RMSE）分别为4.48 kt、5.78 kt和13.94 kt。通过与官方机构的TC记录对比,验证了该模型的有效性。
相似文献16.
An atmosphere-only model system for making seasonal prediction and projecting future intensities of landfalling tropical cyclones (TCs) along the South China coast is upgraded by including ocean and wave models. A total of 642 TCs have been re-simulated using the new system to produce a climatology of TC intensity in the South China Sea. Detailed comparisons of the simulations from the atmosphere-only and the fully coupled systems reveal that the inclusion of the additional ocean and wave models enable differential sea surface temperature responses to various TC characteristics such as translational speed and size. In particular, interaction with the ocean does not necessarily imply a weakening of the TC, with the coastal bathymetry possibly playing a role in causing a near-shore intensification of the TC. These results suggest that to simulate the evolution of TC structure more accurately, it is essential to use an air-sea coupled model instead of an atmosphere-only model. 相似文献
17.
A new parameterization scheme of sea surface momentum roughness length for all wind regimes, including high winds, under tropical cyclone (TC) conditions is constructed based on measurements from Global Positioning System (GPS) dropsonde. It reproduces the observed regime transition, namely, an increase of the drag coefficient with an increase in wind speed up to 40 m s-1 , followed by a decrease with a further increase in wind speed. The effect of this parameterization on the structure and intensity of TCs... 相似文献
18.
This study examines the long-term change in the threat of landfalling tropical cyclones(TCs) in East Asia over the period 1975–2020 with a focus on rapidly intensifying(RI) TCs. The increase in the annual number of RI-TCs over the western North Pacific and the northwestward shift of their genesis location lead to an increasing trend in the annual number of landfalling RI-TCs along the coast of East Asia. The annual power dissipation index(PDI), a measure of the destructive potential of RI-TCs at landfall, also shows a significant increasing trend due to increases in the annual frequency and mean landfall intensity of landfalling RI-TCs. The increase in mean landfall intensity is related to a higher lifetime maximum intensity(LMI) and the LMI location of the landfalling RI-TCs being closer to the coast. The increase in the annual PDI of East Asia is mainly associated with landfalling TCs in the southern(the Philippines, South China, and Vietnam) and northern parts(Japan and the Korean Peninsula) of East Asia due to long-term changes in vertical wind shear and TC heat potential. The former leads to a northwestward shift of favorable environments for TC genesis and intensification, resulting in the northwestward shift in the genesis, RI, and LMI locations of RI-TCs. The latter provides more heat energy from the ocean for TC intensification, increasing its chances to undergo RI. 相似文献
19.
20.
We use FLIGHT+ aircraft reconnaissance data for tropical cyclones (TCs) in the North Atlantic and Eastern Pacific from 1997 to 2015 to re-examine TC fullness (TCF) characteristics at the flight level. The results show a strong positive correlation between the flight-level TCF and the intensity of TCs, with the flight-level TCF increasing much more rapidly than the near-surface TCF with increasing intensity of the TCs. The tangential wind in small-TCF hurricanes is statistically significantly stronger near the eye center than that in large-TCF hurricanes. Large-TCF hurricanes have a ring-like vorticity structure. No significant correlation is observed between the flight-level TCF and the comparative extent of the vorticity-skirt region occupied in the outer core skirt. The proportion of the rapid filamentation zone in the outer core skirt increases with increasing flight-level TCF. The differences in entropy between the radius of the maximum wind and the outer boundary of the outer core skirt also increase with increasing flight-level TCF. 相似文献