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11.
用2002年3个热带气旋登陆广东的过程中自动站的降水资料, 对TRMM准全球、准实时的3 h降水估测资料进行了检验, 表明该资料与地面3 h降水有很好的相关性, 可以反映出热带气旋3 h降水变化的特征。利用该资料分析了这3个热带气旋登陆过程中不同半径、不同方向降水的时空变化特征, 并分析了不同热带气旋之间降水差异的大尺度环流背景。研究发现, 3个热带气旋登陆过程中心附近降水沿半径方向存在收缩和扩展的变化, 除了低层水汽输送的变化和地形对降水造成影响之外, “北冕”和“黄蜂”都发现热带气旋外围降水加强会导致其中心附近降水减弱, 这与以往的观测及研究成果类似。 相似文献
12.
The NCEP 1°×1°reanalysis of June-to-September dataset between 2002 to 2009 is used in this study to conduct statistical analysis of the relationship between the environmental potential vorticity(PV)on 150 hPa located at the south edge of South Asia High(SAH)and TCs making landfall.The results show that 23 of the TCs are affected by the PV on 150 hPa located at the south edge of SAH between 2002 to2009,and three TCs'center pressure decline after the high-value environmental PV moves to the center of the TCs.These three TCs are Senlaku(0216),Bilis(0604)and Linfa(0903).Through diagnostic analysis from the viewpoint of isolines,we determined the relationship between the intensification of these TCs and the PV anomaly at high levels;the isentropic surface is close to the high level’s PV anomaly under the influence of the 150-hPa PV anomaly,leading to the decline of isentropic surfaces on both sides of the PV anomaly.Then the warm core of the middle and high levels of the TC strengthens and PV increases at the middle level,and both of them are beneficial to the reinforcement of the cyclonic vorticity in the low level.As a result,the center pressure of the TC declines.According to Wu’s theory of Slantwise Vorticity Development(SVD),the incline of the isentropic surfaces leads to the development of vertical vorticity,contributing to the vertical motion and the release of the latent heat.Then the warm core of the TC strengthens and the TC strengthens,too.Otherwise,piecewise PV inversion also shows that the high-level PV influences the mid-level more than the low level. 相似文献
13.
RESEARCH PROGRESS ON THE STRUCTURE AND INTENSITY CHANGE FOR THE LANDFALLING TROPICAL CYCLONES 总被引：2，自引：2，他引：0
陈联寿 《热带气象学报(英文版)》2012,18(2):113-118
Landfalling tropical cyclones(LTCs)include those TCs approaching the land and moving across the coast.Structure and intensity change for LTCs include change of the eye wall,spiral rain band,mesoscale vortices,low-layer shear lines and tornadoes in the envelope region of TC,pre-TC squall lines,remote rain bands,core region intensity and extratropical transition(ET)processes,etc.Structure and intensity change of TC are mainly affected by three aspects,namely,environmental effects,inner core dynamics and underlying surface forcing.Structure and intensity change of coastal TCs will be especially affected by seaboard topography,oceanic stratification above the continental shelf and cold dry continental airflow,etc.Rapid changes of TC intensity,including rapid intensification and sudden weakening and dissipation,are the small probability events which are in lack of effective forecasting techniques up to now.Diagnostic analysis and mechanism study will help improve the understanding and prediction of the rapid change phenomena in TCs. 相似文献
14.
Radiocarbon assays of sediments from Lake Shelby, US Gulf Coast, exhibit substantial 14C deficiencies of 9.3% and 4.7% for the limnic sapropel and associated fresh-water clams Rangia cuneata, respectively. Measured radiocarbon dates from the sapropel and clams require corrections of 785 ± 80 and 365 ± 90 14C yr (1σ), respectively, in order to achieve consistency with the radiocarbon time scale. Lake sediments of the US Gulf Coast serve as unique repositories of pre-historic hurricane strikes. Previously unrecognized radiocarbon deficiencies likely render compromised chronologies of the paleo-hurricane records, and erroneous estimates of return period and landfall probability that are derived from the storm chronologies. The recalculated severe hurricane chronologies suggest that the annual landfall probabilities of the last millennium on the US Gulf Coast are equal to, or higher than, the preceding three millennia. 相似文献
15.
Bangladesh is highly susceptible to tropical cyclones. Unfortunately, there is a dearth of climatological studies on the tropical
cyclones of Bangladesh. The Global Tropical Cyclone Climatic Atlas (GTCCA) lists historical storm track information for all
the seven tropical cyclone ocean basins including the North Indian Ocean. Using GIS, tropical cyclones that made landfall
in Bangladesh during 1877–2003 are identified and examined from the climatological perspective. For the convenience of study,
the coast of Bangladesh is divided into five segments and comparisons are made among the coastal segments in terms of cyclone
landfall and vulnerability. There is a large variability in the year-to-year occurrence of landfalling tropical cyclones in
Bangladesh. Most of the tropical cyclones (70%) hit in the months of May–June and October–November generally show the well-known
pattern of pre- and post-monsoon cyclone seasons in that region. 相似文献
16.
本文使用西北太平洋累积气旋能量(ACE)月尺度异常序列,对850 hPa相对涡度、地表纬向风、柱水汽含量、OLR、降水和SST等大尺度环境场变量进行时滞回归分析,讨论了月尺度TC活动对大尺度环境场的影响及其与周尺度的区别和联系.结果表明:(1)月尺度ACE回归出的纬向风无论是强度还是范围都要明显大于周尺度ACE回归结果,TC的频繁发生,尤其是强度大且持续时间长的近赤道TC,对于激发或加强TC活动区域南侧的低纬地区西风异常有一定的积极作用,持续并且强度较大的西风异常可能导致西风的爆发,而西风爆发会在很大程度上影响ENSO事件的发生和演变.(2)在月尺度上,OLR、柱水汽含量、降水和SST等物理量均呈现出较为明显的E1Nino型分布,而在周尺度上,仅SST呈现出明显的El Nino型分布,这在一定程度上反映了月尺度TC活动和太平洋ENSO信号之间存在更密切的关联.(3)在TC发生后1-2月,TC的主要生成区域柱水汽含量减少、OLR增大,这会在一定程度上降低该区域生成TC的潜能.虽然TC所引起SST降低的空间尺度很小,但其通过大气和海洋的传导会扩大到更大尺度上,由于这种反馈具有一定的滞后性,所以月尺度TC对大尺度环境场影响的信号更为显著. 相似文献
17.
台风登陆前后异常变化的研究进展 总被引：15，自引：1，他引：14
国家重点基础研究发展计划（973计划）项目——“台风登陆前后异常变化及机理研究”经过5年（2009—2013年）的研究完成研究任务。项目系统性地开展了16个台风的外场观测试验,在浅水区的海气拖曳系数、边界层高度变化等方面获得新的观测结果;发展了针对登陆台风的多源资料融合方法,例如台风雷达风场反演和同化技术取得进展;揭示了不同尺度系统活动导致台风路径突变、登陆台风复苏、双眼壁的形成等的物理机制;改进了涡旋初始化和积云对流参数化技术,提出了新的云辐射参数化方案,建立了台风海-陆-气耦合模式,台风数值预报关键技术的研发取得明显进展,文中介绍该项目所取得的代表性成果,对台风登陆前后异常变化的科学问题及研究进展进行综述。 相似文献
18.
登陆中国热带气旋入海强度变化的统计特征 总被引：3，自引：2，他引：1
利用1949—2006年热带气旋资料分析登陆中国又入海的热带气旋(LSTC)的强度变化,重点给出明显加强的LSTC(RLSTC)发生频率、时空分布、路径及强度演变特征。主要结论:(1)LSTC入海有24%加强,主要在我国海域,也有少部分进入朝鲜海峡、日本海和鄂霍次克海加强;登陆大陆入海加强的比率明显高于登陆台湾或登陆海南的比率。(2)RLSTC年平均有0.7个,逐年代减少,8月最多。(3)中心最低气压和最大风速加强最强的月份分别在8月和10月、加强最强的海域分别在南海和东黄海。(4)登陆时强度为强热带风暴的最多;其路径除了移向稳定者外,在南海和北部湾还有迂回盘转式。(5)明显加强主要发生在入海时刻,很少持续明显加强。进入东黄海的RLSTC以最大风速先于中心气压变化或仅有风速加强的情况居多,进入南海、北部湾入海后的风速、气压基本同步加强,迂回路径可在入海后72～132小时还会加强。 相似文献
19.
1011号台风“凡亚比”登陆过程数值模拟及诊断分析 总被引：2，自引：0，他引：2
利用中尺度非静力数值模式WRF V3.2.1对“凡亚比”台风(1011)的登陆过程开展了高分辨率数值模拟,模拟采用三重嵌套,最高分辨率为3 km,共积分120 h(5 d)。利用收集到的观测资料对模式模拟的结果进行了较细致的对比验证。结果表明,模式较好地模拟再现了“凡亚比”台风的发展演变以及两次登陆过程,模拟的台风路径与观测路径较为一致,模式也较好地把握住了“凡亚比”台风的强度演变过程,模拟取得了初步的成功。进一步利用高分辨率模拟资料对此次台风登陆过程的强降水开展了初步诊断分析,结果表明,在整个研究时段内,散度垂直通量绝对值的垂直积分<|Q|>与地面降水区有很好的对应,两者在空间分布和时间演变上比较一致,在降水大的区域<|Q|>的值也大,这表明<|Q|>对“凡亚比”台风强降水具有较好的诊断和指示意义。 相似文献
20.
A method is introduced for assessing the probabilities and intensities of tropical cyclones at landfall and applied to data
from the North Atlantic. First, a recently developed model for the basin-wide Monte-Carlo simulation of tropical cyclone tracks
is enhanced and transferred to the North Atlantic basin. Subsequently, a large number of synthetic tracks is generated by
means of an implementation of this model. This synthetic data is far more comprehensive than the available historical data,
while exhibiting the same basic characteristics. It, thus, creates a more sound basis for assessing landfall probabilities
than previously available, especially in areas with a low historical landfall frequency. 相似文献