白莉娜,何敏,王元,任福民,陈联寿. 2010. 西北太平洋风速垂直切变异常对热带气旋活动年际变化的影响[J]. 气象学报, 68(6):877-884, doi:10.11676/qxxb2010.083
西北太平洋风速垂直切变异常对热带气旋活动年际变化的影响
The influence of the vertical wind shear variation on interannual changes in the tropical cyclone activity in the western North Pacific.
投稿时间:2008-10-10  修订日期:2009-05-18
DOI:10.11676/qxxb2010.083
中文关键词:  风速垂直切变, 热带气旋, 季风槽, 低层涡度, 高低层散度
英文关键词:Vertical wind shear, Tropical cyclone, Monsoon trough, Vorticity in the lower troposphere, Divergence in the upper and lower troposphere
基金项目:国家自然科学基金项目 (40830958、40730948、40775046、90715031)、国家重点基础研究发展规划项目(973)课题 (2009CB421502)与上海台风研究基金课题(2008ST08)
作者单位
白莉娜 南京大学大气科学学院中尺度灾害性天气教育部重点实验室南京210093 
何敏 国家气候中心北京100081 
王元 南京大学大气科学学院中尺度灾害性天气教育部重点实验室南京210093 
任福民 国家气候中心北京100081 
陈联寿 中国气象科学研究院北京100081  
摘要点击次数: 3511
全文下载次数: 2938
中文摘要:
      应用中国《台风年鉴》资料、欧洲中心40年月平均再分析资料和NOAA的逐月海温资料,研究了西北太平洋(5°—30°N,110°E—180°)风速垂直切变异常对热带气旋(TC)活动年际变化的影响。研究发现,西北太平洋所有TC、风暴以上级别的TC (TSTY, 即达到热带风暴级别及以上的所有TC) 和所有台风(WTY,包括台风、强台风和超强台风) 年频数与西北太平洋风速垂直切变都显著负相关。西北太平洋风速垂直切变大小对生成源地在南海 (5°—30°N,110°—120°E) TC和西北太平洋西部海域 (5°—30°N,120°—150°E) TC的影响较小,而对西北太平洋东部海域 (5°—30°N,150°E—180°) 生成的TC影响最大:即西北太平洋风速垂直切变负异常年,有利于西北太平洋东部海域TC生成发展,使得负异常年较正异常年TC频数偏多和源地平均位置偏东;并且风速垂直切变的变化对TC频数和生成源地影响的显著性,随着TC强度的增加而增加。对TSTY生成环境场的进一步分析表明,西北太平洋风速垂直切变偏小年,季风槽偏强位置偏东,它的东端位于宽阔的太平洋洋面,与弱风速垂直切变区相配合,暖的海温加上低层强烈的正涡度和强烈辐合,且相应的高层有强的气流辐散区,这些环境场都有利于TSTY在主要源地尤其是西北太平洋东部海域生成,这是风速垂直切变偏小年TSTY偏多和生成源地偏东的重要原因。
英文摘要:
      Based on the tropical cyclone data from China Meteorological Administration (CMA), the sea surface temperature monthly data from National Oceanic and Atmospheric Administration (NOAA) and the monthly reanalysis data provided by the European Center for Medium range Weather Forecasts(ECMWF) for the period of 1958-2001, the influence of the vertical wind shear variation on interannual changes in the tropical cyclone (TC) activity in the western North Pacific was examined. It is found that there exist strong negative correlations between occurrence frequencies of TC the whole/TSTY (all the TC with the maximum sustained wind equal or greater than 17.2 m/s)/WTY (including typhoon, severe typhoon and super typhoon) and vertical wind shear in the western North Pacific (WNP, 5°-30°N,110°E-180°). Such an effect is not significant for the TCs initiated in South China Sea (5°-30°N, 110°-120°E) and the western part of the WNP (5°-30°N, 120°-150°E), while the TC frequency of the eastern part of the WNP (5°-30°N, 150°E-180°) varies remarkably according to vertical wind shear. In the weaker vertical wind shear years, TC frequencies in South China Sea and the western part of the WNP are not very different from those in normal years, while the TC number of the eastern part of the WNP is much larger than that in normal years, which makes the total TC number in the WNP being larger and causes the average original location to shift more eastward than the normal. In stronger wind shear years, the statistical results are reverse. Furthermore, the effect of vertical wind shear on the TC annual frequency and the position becomes more significant for stronger TCs. At last, the difference of climatic environmental field between weaker vertical wind shear years and stronger years has been compared. In weaker vertical wind shear years, the monsoon trough is more vigorous and extends eastward to the 160°E, and the vorticity and convergence in the lower troposphere, as well as the divergence in the upper troposphere are all enhanced significantly over the warmer ocean. These environment conditions are favorable to the TSTY genesis in the WNP, which results in a larger number of TSTY during weaker vertical wind shear years. The largest difference of these environmental conditions between weaker and stronger wind shear years is in the eastern part of the WNP, which is an important reason causing the eastward movement of the genesis location in weaker wind shear years.
HTML   查看全文   查看/发表评论  下载PDF阅读器
分享按钮