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1.
Development of an Integrated Vertical-Slantwise Convective Parameterization Scheme and Its Associated Numerical Experiments 
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下载免费PDF全文 FEI Jianfang WU Rongsheng HUANG Xiaogang WANG Yuan CHENG Xiaoping 《Acta Meteorologica Sinica》2011,25(4):405-418
An integrated vertical-slantwise convective parameterization scheme,based on the vertical Kuo-Anthes and the slantwise Nordeng convective parameterization schemes,is introduced into the MM5 model.By employing the MM5 model with the proposed scheme,numerical simulations of a snowstorm event that occurred over southern China on 28 29 January 2008 and of Typhoon Haitang (2005) are conducted.The results indicate that during the snowstorm event,the atmosphere was convectively stable in the vertical direction but with conditional symmetric instability (CSI) in the lower troposphere,and when the area of CSI developed and extended to upper levels,strong rising motion occurred and triggered the release of large amount of energy,producing enhanced convective precipitation with the total precipitation much closer to the observation.The development and strengthening of CSI corresponded to changes in the intensity of snowfall,convergence,and ascending motions of air,revealing that CSI was responsible for the initiation and growth of the snowstorm.The results from a 72-h explicit simulation of Typhoon Haitang indicate that CSI occurred mainly at lower levels with a well-defined spiral structure,and it tended to have a larger impact on the intensity of typhoon than on its track.The minimum pressure at the typhoon center for the 72-h runs with the integrated vertical-slantwise convective parameterization scheme was on average 3 hPa (maximum 8 hPa) lower than that from the runs with only the vertical cumulus parameterization scheme.Introducing the influence of CSI into the model has improved the warm core structure at the middle and upper levels of the typhoon,with stronger and persistent upward motions causing increased precipitation,and the latent heat released through convection in turn made the typhoon develop further. 相似文献
2.
垂直-倾斜对流一体化参数化方案的实现及数值试验 总被引：1，自引：0，他引：1
在Kuo-Anthes垂直对流参数化方案和Nordeng倾斜对流参数化方案基础上,提出了垂直-倾斜对流一体化参数化方案,并引入MM5模式中.利用该方案对2008年1月28-29日发生在中国南方的一次暴雪过程和2005年"海棠"台风过程进行了数值模拟,模拟结果表明,此次暴雪过程在垂直方向主要表现对流稳定状态,但在对流层低层始终存在条件件对称不稳定层,并且当条件性对称不稳定区向高层发展时,伴随着强上升运动作为触发机制,引发条件性对称不稳定能量的释放,产生更多的对流降水,使模拟的总降水量与实况更加一致.条件性对称不稳定的发展加强与降雪强度、辐合辐散和上升运动变化一致,条件性对称不稳定是造成暴雪发展加强的主要机制之一.通过对"海棠"台风72 h的模拟表明,条件性对称不稳定主要发生在台风的低层,且其水平分布呈螺旋状结构.条件性对称不稳定效应对台风路径影响较小,但对台风强度影响较大,在模式中考虑垂直-倾斜对流一体化参数化方案后,与仅考虑垂直积云对流参数化方案相比,72 h模拟的平均台风中心最低气压降低了3 hPa,最大达8 hPa.在模式中考虑条件性对称不稳定的影响,可使模式台风中上层的暖心结构更加明显,上升运动和对流性降水增强,对流释放的更多凝结潜热使台风得到进一步加强. 相似文献
3.
The impact of different cloud microphysics parameterization schemes on the intensity and structure of the
Super-strong Typhoon Rammasun (1409) in 2014 is investigated using the Weather Research and Forecasting model
version 3.4 with eight cloud microphysics parameterization schemes. Results indicate that the uncertainty of cloud
microphysics schemes results in typhoon forecast uncertainties, which increase with forecast time. Typhoon forecast
uncertainty primarily affects intensity predictions, with significant differences in predicted typhoon intensity using the
various cloud microphysics schemes. Typhoon forecast uncertainty also affects the predicted typhoon structure.
Greater typhoon intensity is accompanied by smaller vortex width, tighter vortex structure, stronger wind in the
middle and lower troposphere, greater height of the strong wind region, smaller thickness of the eyewall and the
outward extension of the eyewall, and a warmer warm core at upper levels of the eye. The differences among the
various cloud microphysics schemes lead to the different amounts and distributions of water vapor and hydrometeors
in clouds. Different hydrometeors have different vertical distributions. In the radial direction, the maxima for the
various hydrometeors forecast by a single cloud microphysics scheme are collocated with each other and with the
center of maximum precipitation. When the hydrometeor concentration is high and hydrometeors exist at lower
altitudes, more precipitation often occurs. Both the vertical and horizontal winds are the strongest at the location of
maximum precipitation. Results also indicate that typhoon intensities forecast by cloud microphysics schemes
containing graupel processes are noticeably greater than those forecast by schemes without graupel processes. Among
the eight cloud microphysics schemes investigated, typhoon intensity forecasts using the WRF Single-Moment 6-class
and Thompson schemes are the most accurate. 相似文献
4.
利用常规观测资料、NCEP FNL再分析资料、卫星和雷达资料等对2012年台风“达维”（过程1）和2017年台风“海棠”（过程2）导致的辽宁东南半岛两次极端暴雨过程的降水特征及成因进行对比分析。结果表明: 两次过程的降水特征存在差异,过程1是大范围的稳定持续性暴雨,受台风倒槽触发的多个中尺度云团造成的列车效应影响,持续时间长达30 h; 而过程2的小时雨强更大,最强达到113 mm·h-1,小尺度积云不断新生并涌入到中尺度云团中,雷达图存在后向传播特征,强风暴基本反射率达到50—60 dBz,中尺度辐合风场伸展高度达到9 km,对流云发展更旺盛,过程2的对流性降水特征更明显。过程1暴雨在台风倒槽里发展,过程2在台风输送的暖湿空气与对流层干冷空气的相互作用中产生。两次过程中,台风残涡与副热带高压间均形成了横跨10个纬距的水汽输送带,850 hPa水汽通量均达到20—25 g-1·cm-1·hPa-1·s-1,比湿和水汽通量散度达到辽宁登陆台风暴雨物理量的预报阈值; 远距离台风对阻挡副热带高压南落和建立北上台风引导气流起到关键作用。过程1受“达维”残涡倒槽影响,辐合层由地面伸展到500 hPa,动力抬升条件更强; 过程2中850 hPa假相当位温达到354 K,由于中层干空气侵入,位势不稳定较强,在大尺度辐合和地形强迫抬升作用下,形成更为深厚对流云,对流性降水特征明显。 相似文献
5.
YU Zhenshou NI Donghong GAO Shouting MIN Jinzhong REN Hongxiang 《Acta Meteorologica Sinica》2008,22(2):224-238
Typhoons landing in the central and north of Fujian Province often seriously impact Zhejiang Province. Much attention has been given to exceptionally torrential rain in the South/North Yandang mountainous regions in the southeast of Zhejiang Province associated with typhoon-landing. Typhoon Haitang （2005） is a typical case of such a category, which landed in Huangqi Town of Lianjiang County in Fujian Province, and meanwhile greatly impacted Southeast Zhejiang. A numerical simulation has been performed with the PSU/NCAR non-hydrostatic model MM5V3 to study the torrential rain associated with Typhoon Haitang. The comparison of simulated and observed rainfalls shows that the MM5V3 was able to well simulate not only the intensity but also the locations of severe heavy rain of Typhoon Haitang, especially the locations of the south/north heavy rain center areas in the South/North Yandang mountainous regions. Meanwhile, the diagnostic analysis has been also carried out for better understanding of the severe heavy rain mechanism by using the model output data of high resolution. The diagnostic analysis indicates that the westward tilt of the axis of vorticity from lower layer to upper layer over the south heavy rain center area and the coupled structure of convergence in the lower layer and divergence in the upper level over the north heavy rain center area, were both propitious to stronger upward motion in the layers between the mid and upper atmosphere, and the secondary circulation induced by the vertical shear of the ambient winds further strengthened the upward motion in the heavy rain areas. After Haitang passed through Taiwan Island into the Taiwan Strait, the water vapor east of Taiwan Island was continuously transferred by typhoon circulation towards South Wenzhou, leading to the torrential rainfall in the South Yandang mountainous region south of Wenzhou. Subsequently~ Haitang moved northwards, the water vapor belt east of Taiwan Island slowly advanced northwards, the precipitation rate obviously enhanced i 相似文献
6.
By using WRF mesoscale model, this paper carries out a numerical simulation and diagnostic
analysis of the structural characteristics of the asymmetric spiral rain bands around the landing of Typhoon
Haitang during the period of July 19 to 20, 2005. The result indicated that the two rainbands associated
with the precipitation centre was mainly located northeast of the typhoon centre. The movement and
intensity of the southern rainband corresponded well with the 850-hPa positive vorticity band from 0200 to
1800 UTC July 19, 2005. Under the effect of cyclonic circulation, the positive vorticity band at 850 hPa
connected with a southern rain band, leading to the intensification of rainfall in the southern centre of the
precipitation. The southward rainband gradually moved toward and then merges with the northward one,
strengthening the rainfall in the northern centre of the precipitation. Besides, the relationship between the
heavy rainfall and the divergence field of vertical shear wind in the high altitude is analyzed. Finally, the
relationship is revealed between the development of the vertical component of convective vorticity vector
and the rainfall near the two centres of precipitation in the low altitude. 相似文献
7.
利用常规观测、NCEP FNL、葵花8号卫星、GNSS反演大气可降水量、智能网格实况产品等资料,分析2017年“海棠”台风造成辽宁西部朝阳地区和东南部岫岩县的极端暴雨成因。结果表明：辽宁西部和东南半岛均出现区域性的极端特大暴雨,岫岩县小时雨强更大,最大雨强达到113 mm·h-1,对流性降水特征明显。两个区域暴雨过程均受到热带、副热带、西风带系统共同作用,狭长型“海棠”台风沿着副热带高压西侧逐渐北上,并且与西风带短波槽相互作用,导致辽宁西部出现强降水,随后加强的涡旋系统后侧干冷空气与低空暖湿水汽输送带相互作用,导致岫岩县出现极端暴雨过程。热带台风“奥鹿”对副热带高压南落东退起到阻挡作用。两个区域均具有来自于南海的水汽通道,另外东南半岛也受到了“奥鹿”台风北侧水汽输送的影响。朝阳市和岫岩县大气可降水量值长时间接近65 mm和70 mm,异常指数最高达到3.0和2.5,表明此次暴雨水汽条件的极端性。辽宁西部降水期间动力不稳定更强,辐合层由地面伸展到500 hPa,而东南半岛降水期间上干下湿的水汽分布以及更强的冷暖空气交汇,有利于产生对流性降水。两个区域均受到多个中尺度云团的共同影响,朝阳地区初期降水由中γ尺度辐合线触发,后期台风在北上过程中与高空槽后部的干冷空气相互作用,形成的暖锋云系以及冷锋云系导致朝阳地区出现持续性强降水;加强的涡旋后部干空气侵入到暖湿水汽输送带中,配合岫岩县山区地面辐合线稳定不动,不断有积云触发并且直接影响岫岩县,导致岫岩县产生极端对流性暴雨。 相似文献
8.
台风“海棠”特大暴雨数值模拟研究 总被引：12，自引：1，他引：12
在福建中北部登陆的台风,往往会严重影响浙江,尤其值得注意的是台风引起特大暴雨经常会发生在浙江东南沿海的南雁荡山区和北雁荡山区,2005年在福建省连江黄歧登陆的台风"海棠"(0505)对浙江东南沿海造成严重影响,是这类台风比较典型个例。文中利用非静力模式MM5模拟"海棠"台风在浙东南沿海造成的特大暴雨,模拟结果与实况对比分析表明,模式较好地模拟了台风降水强度和分布,特别是成功模拟出南雁荡山区特大暴雨中心(南部暴雨区)和雁荡山区特大暴雨中心(北部暴雨区);运用高时空分辨率模拟资料对特大暴雨成因进行诊断分析表明,南部暴雨区涡度低层到高层向西倾斜结构和北部暴雨区高低空强辐散辐合的耦合结构有利于形成暴雨区强烈上升运动,环境风场垂直切变产生次级环流进一步加强暴雨区上升运动;暴雨区持续不稳定层结和特殊水汽输送通道为特大暴雨提供热力条件和水汽条件。最后对浙南闽北地形对台风特大暴雨影响进行数值敏感性试验表明,温州南、北雁荡山脉地形等高线与台风水汽输送路径正交是造成特大暴雨的重要原因,地形使暴雨增幅明显,地形越高对暴雨增幅越明显,降水分布更加不均匀。比较台风造成南、北特大暴雨条件,发现两者既有环境风场垂直切变产生次级环流进一步加强暴雨区上升运动、持续不稳定层结以及地形对暴雨增幅作用等相同之处,又有动力结构、维持持续不稳定层结条件以及水汽输送等不同之处。 相似文献
9.
利用地面观测资料、雷达资料、FY-2G卫星云图资料及欧洲中心细网格资料,对台风利奇马登陆北上引发山东特大暴雨的成因进行分析。发现:利奇马登陆北上过程中,冷空气先后从台风的西部、西南部与南部侵入至台风中心内部,使其暖心结构逐渐减弱,其变性时段发生在10日20:00至11日08:00。山东的特大暴雨主要出现在台风变性前12h至台风变性后6h。变性之前的暴雨主要是由于台风螺旋云带与高空槽尾部云系相叠加造成的,变性之后的暴雨则是由于冷空气侵入致使台风外围云系演变成强对流复合体造成的。变性之前,对流层内800～500hPa风速小,500～250hPa风速大,气层内有暖平流,整层的上升运动,降水以暖区对流降水为主;变性之后800～500hPa风速大,500～250hPa风速小,500hPa至地面是上升运动,以上为下沉运动,降水以斜压锋区附近的对流降水为主。当500hPa至地面气层内出现冷平流时,湿层变薄,降水趋于减弱。特大暴雨区出现在台风中心西北方向,与850hPa假相当位温锋区与水汽通量散度辐合大值区相吻合。 相似文献
10.
The distribution of precipitation field from the typhoon Haitang (2005)
during its landing on Fujian province shows obvious asymmetric feature. Based on
the NCEP/NCAR FNL (Final Analysis) data, this study reveals the contributions of
atmospheric factor to the asymmetrical distribution characteristics of
precipitation associated with the typhoon, through the analysis of water vapor
condition, vertical ascending motion condition, the calculation of the dry Q
vector and its decomposition, and adiabatic heating in the air column of 1000hPa
-600hPa (lower atmosphere) and 500hPa-100hPa (upper atmosphere). The results are
as follows: (1) In the lower atmosphere, the humidity on both sides of typhoon
path can be equivalent, while it is more wet on the right side than left in the
upper atmosphere, which obviously presents asymmetric distribution
characteristics. (2) Both range and intensity of the vertical motion on the right
side are wider and stronger than counterparts on the left side no matter in the
lower or upper atmosphere. (3) In the upper atmosphere, forcing role of
atmosphere in vertical upward motion on the right side of typhoon path is the
same as that on the left, while it is significantly different in the lower
atmosphere, which is significantly broader in scope and stronger in the
intensity, along with obvious asymmetric distribution characteristics. In
addition, the further analysis of the Q vector decomposition indicates that the
forcing effect of mesoscale weather systems on vertical upward motion is stronger
than that of large scale weather systems in the lower atmosphere. (4) The
adiabatic heating always exists on both lower and upper atmosphere, and the range
and intensity of the adiabatic heating forcing showed asymmetric distribution on
both lower and upper atmosphere. (5) In a summary, the upper atmosphere humidity
conditions, the forcing role of lower atmosphere in vertical upward motion,
especially, to mesoscale weather system, and adiabatic heating in the lower
atmosphere, all show similar asymmetric distribution characteristics to that of
precipitation field from the typhoon Haitang (2005), that is to say, the
atmospheric factors as mentioned above are all contributed to genesis of the
asymmetric distribution characteristics of precipitation. 相似文献
11.
2003年春季江淮一次暴雪过程的模拟研究 总被引：24，自引：3，他引：24
采用NCEP全球再分析资料和常规地面、高空观测资料，利用非静力中尺度数值模式MM5（V3．6）对2003年2月江淮地区暴雪过程进行了数值模拟。结果表明，MM5能够较好地模拟出地面及中低空大、中尺度环流系统，能够成功模拟出暴雪中尺度低涡的发生、发展及结构演变；低空西南急流与暴雪有着密切关系，对暴雪天气预报有很好的指导作用；对涡度场、散度场和垂直速度场的诊断表明，运动场和热力场的相互配置及耦合关系非常有利于暴雪切变线的发展及暴雪形成与维持。还利用模拟雷达反射率因子检验了模拟的正确性。对温度场的分析可知。降水性质与700hPa、850hPa温度平流有直接关系。 相似文献
12.
大连两次台风暴雨过程对比分析 总被引：1，自引：0，他引：1
利用常规气象资料、加密气象自动观测站资料及NCEP再分析资料对2017年8月3日和2012年8月3日发生在大连地区的“海棠”(1710)和“达维”(1210)两次台风暴雨过程进行对比诊断分析。通过对台风路径、环流形势、双台风相互作用等方面进行对比分析。结果表明:这两次台风暴雨过程的降水系统为典型的双台风降水模型,在两个台风的北部都有不同强度的冷空卷入,触发对流不稳定,有利于中尺度暴雨云团的发展。低层850hPa上均有不同程度的切变辐合,高空有急流的建立;两次过程主要降水时段内强降水中心从低层到高层均出现了强烈的上升运动,暴雨中心上空维持着高层辐散、低层辐合。日本海南部存在台风迫使副热带高压转为径向型或形成阻塞高压,双台风或三台风与副热带高压之间形成的低空急流为暴雨的生成和维持提供了有利的动力条件和水汽条件。台风“海棠”残余环流与高空槽相结合,高空槽带来的冷空气更加强烈,锋生效果更加明显,这种情况更有利于强对流的发生发展。台风“苏拉”与影响大连的台风“达维”相互作用导致强降水阶段暖湿气流更加旺盛,降水持续时间更长,范围更广。 相似文献
13.
Betts对流调整方案在移动套网格台风数值模式中的初步试验 总被引：1，自引：1，他引：0
Betts对流调整方案采用的是垂直温湿场向观测的准平衡热力结构松驰的方法。本文在一个考虑了台风初值化的移动套网格台风数值模式中,对Betts方案进行了初步试验。结果表明：Betts方案能较好的预报出台风移动的路径和降水过程,并在台风路径、降水落区预报以及对流增温的垂直分布等方面都略优于Kuo方案的预报结果。 相似文献
14.
利用云南省自动气象站雨量资料、卫星和闪电定位仪资料、雷达回波资料、NCEP 1 °×1 °再分析资料和地面、高空常规观测资料对云南一次典型的台风前侧短时强降水过程的成因进行分析,结果表明:在2017年13号台风“天鸽”西行影响云南的天气背景之下,短时强降水出现在台风前侧700 hPa风速辐合区和边界层辐合线附近。台风前侧偏东低空急流向云南境内输送水汽和能量,边界层辐合线触发垂直上升运动,700 hPa风速辐合区利于垂直上升运动的维持和加强,促使水汽的辐合与不稳定能量的释放,引发短时强降水。在中等强度深层垂直风切变的作用下,云南东部中尺度对流系统(MCS)频繁产生并向西传播发展,MCS相互作用组织成飑线系统,在东北气流的引导下,飑线从云南中部移至云南西南部,MCS和飑线是大范围短时强降水的直接影响系统。 相似文献
15.
16.
A Study on Typhoon-Induced Rainfalls over Beijing: Statistics and Case Analysis 总被引：1，自引：0，他引：1 下载免费PDF全文
下载免费PDF全文 Based on the Shanghai Typhoon Institute (STI) Typhoon Year Book and typhoon precipitation data,
Japan Meteorological Agency satellite TBB data, and National Centers for Environmental Prediction (NCEP)
reanalysis data, the climatic characteristics of rainfalls in Beijing associated with typhoons were analyzed
for the period 1949–2006, and two typhoon cases with remarkable differences in rainfall intensity over Beijing
were compared and diagnosed. The 58-yr statistical results show that rainfall events associated with
typhoons occurred in Beijing about once every three years during June–September. These typhoons were
mainly active in the region 20?–50?N, 109?–128?E and most of them moved northwestward while the others
turned to the northeast. The typhoon rainfall over Beijing in general sustained for 2–5 days. Typhoon
centers were usually located in the areas from Jiangxi to Anhui, the Yellow Sea, or near Beijing, when rainstorms
occurred over Beijing. Case study indicates that the 2-day torrential rainfall event that happened in
Beijing in 1984 was due to the interaction between Typhoon Freda (8407) and a westerly trough, while only
a medium-strength rainfall event occurred in Beijing in 2005 in spite of the dominating cyclonic circulation
of Typhoon Matsa (0509) directly over Beijing. It is found that both Freda and Matsa underwent extratropical
transition and possessed an asymmetric structure. The rainfall difference was caused by the fact
that Beijing was located in different convective development areas of the two typhoons. On the other hand,
the lifting conditions were different although plentiful atmospheric moisture and convective unstable energy
existed over Beijing during both events. The ascending motion of warm southerly in Beijing was stronger
and deeper and a larger vertical wind shear was associated with Typhoon Freda. However, the lifting of
water vapor was restrained by the descending motion of northerly cold airflow in Beijing under the impact of
Typhoon Matsa. Besides, it is also found that topography played an important role in the typhoon rainfall
over Beijing. 相似文献
17.
利用一次较成功地模拟了"95.1"青藏高原暴雪过程的MM5中尺度模式输出资料,用非纬向非平行基流中的对称不稳定模式,对"95.1"暴雪发生发展过程的动力学机制进行了三维基流中二维非线性对称不稳定数值模拟试验,结果表明:ψ场和w场的三维配置在降雪发生初期和发展过程中与暴雪带基本一致,说明非线性对称不稳定是这次高原暴雪启动的一种动力学机制。 相似文献
18.
利用气象卫星、多普勒天气雷达、区域自动气象观测站及常规气象观测资料,结合NCEP/NCAR逐日6 h再分析资料（0.25°×0.25°）,对2018年18号台风“温比亚”及其残骸长时间影响山东引发特大暴雨的成因进行分析发现：1）此次极端降水可分为三个阶段,分别受台风外围螺旋云系、倒槽和变性后温带气旋冷锋影响,其中弱冷空气与台风倒槽相互作用对强降水的产生和维持起到了重要作用。2）“温比亚”缓慢北上过程中,强降水落区从台风东侧逆时针转至其北部倒槽附近,并逐渐远离台风中心,台风强度逐渐减弱。3）冷空气在对流层中层与台风倒槽相互作用,中层冷暖平流增强形成锋区,斜压不稳定能量增强,暖湿空气在锋区附近上升,并与低层倒槽辐合上升运动相配合,引发了倒槽附近特大暴雨的发生。4）此次过程中,低空急流稳定维持,源源不断地将水汽自东海输送至台风倒槽附近,水汽输送集中在800 hPa以下,850 hPa水汽通量辐合强度大于8×10-6 g·cm-2·hPa-1·s-1区域与暴雨落区的形态和位置对应良好。5）对流层中层的弱冷空气和低层的强暖湿气流促进了对流不稳定层结的发展和维持,低层强风速带在鲁中山区迎风坡强迫抬升不断触发中尺度对流系统,在中高层气流引导和地形作用下产生“列车效应”,也是此次过程中局地特大暴雨产生的重要因素。 相似文献
19.
The Penn State/ NCAR Mesoscale Model (MM5) is used to simulate the precipitation event that occurred during 1–2 May 1994 to
the south of the Yangtze River. In five experiments the Kain–Fritsch scheme is made use of for the subgrid–scale convective
precipitation, but five different resolvable–scale microphysical parameterization schemes are employed. They are the simple
super-saturation removal scheme, the warm rain scheme of Hsie et al. (1984), the simple ice scheme of Dudhia (1989), the complex
mixed–phase scheme developed by Reisner et al. (1993), and the GSFC microphysical scheme with graupel. Our interest is how
the various resolvable-scale schemes affect the domain-averaged precipitation, the precipitation distribution, the sea level
pressure, the cloud water and the cloud ice. Through a series of experiments about a warm sector rainfall case, results show
that although the different resolvable-scale scheme is used, the differences of the precipitation characteristics among all
five runs are not very obvious. However, the precipitation is over-predicted and the strong mesoscale low is produced by the
simple super-saturation removal scheme. The warm rain scheme with the inclusion of condensation and evaporation under-predicts
the precipitation and allows the cloud water to reach the 300 hPa level. The scheme of the addition of graupel increases the
resolvable-scale precipitation by about 20%-30%. The inclusion of supercooled liquid water in the grid-scale scheme does not
affect significantly the results. 相似文献
20.
The climatology of near-equatorial typhoons over the western-north
Pacific are fully investigated using the JTWC (Joint Typhoon Warning Center)
typhoon record from 1951 to 2006. The result shows that there are seasonal and
decadal variations, as well as a distinctive spatial distribution, of such
events. Among them, Typhoon Vamei is an example of a near-equatorial typhoon
that occurred near Singapore in December of 2001. Using the WRF (Weather and
Research Forecast) model, we attempt to find out how the well known ``wind
surge" of this event contributes to the development of Typhoon Vamei. It is
found that the strong wind surge not only helps to provide advection of
positive vorticity to Vamei between 800 and 500 hPa, but also increases the
convective instability of the lower troposphere, and thus helps to induce
convective outbreaks and rapid intensification. Furthermore, sensitivity
experiments show that terrain and the land-sea distribution have very limited
effects on the formation of Typhoon Vamei in the simulation, but an adequate
Coriolis parameter ($f)$ is still needed for the development of Vamei. 相似文献