【作者】 曹楚；

【导师】 彭加毅； 余锦华；

【作者基本信息】 南京信息工程大学 ， 气象学， 2006， 硕士

【摘要】 本文利用NCEP 1951—2002年的每日四次和月平均的风场的再分析资料(水平分辨率为2.5°×2.5°经/纬度网格)、中国气象局整编出版的《台风年鉴》(1951-1984年)和《热带气旋年鉴》(1985-2002年)所提供的热带气旋的资料和全球地面温度资料,统计分析了在全球变暖的背景下登陆我国台风的特征,并与西北太平洋台风进行了对比;用风场垂直切变和低层涡度这两个参数对西北太平洋热带气旋的发生发展进行了研究,得到如下主要结论:1)在全球变暖背景下,我国登陆台风频数的减少趋势没有西北太平洋台风频数的减少趋势强;登陆台风的平均强度和极端强度均有减弱趋势,极端强度的减弱趋势尤为明显,但其强度弱于西北太平洋台风。在1968—2002年全球明显增暖时段,我国台风登陆位置偏向我国中部,西北太平洋台风在生命史中强度达最强时的位置有向北移动的趋势。2)纬向风切变的零线附近和负切变区为西北太平洋热带气旋的高发区,且纬向风切变的零线与850hp水平流场中东西风切变线的位置很接近,零线西侧由于低层为西风,到高层才转成东风,切变向西为负值,有利于热带气旋的产生,而在零线东侧,和西侧正好相反,切变向东为正值,不利于台风发生。3)负的或弱的风场垂直切变有利于台风的加强发展,而正的大的风场垂直切变不利于台风的发展;风场垂直切变对台风在生命过程中达到最大强度(台风中心的最低气压)的前36小时至后36小时的强度有-1.25—5.5天滞后的相关性,且滞后相关时间在1951—1977年有微弱的上升趋势,而在1977—2002年有微弱的下降趋势。更多还原

【Abstract】 The characteristics of landing typhoon in China is analyzed with global warming, and the differences between the characteristics of landing typhoons in China and the ones of typhoons in the Northwestern Pacific are studied, and tropical cyclogenesis and its development in the Northwestern Pacific are examined through the two parameters of vertical wind shear and low level vorticity by using the NCEP four-time/day reanalysis and monthly mean data for wind field from 1951 to 2002 ( the horizontal resolution of 2.5°x2.5°lat./lon. grid ) , and Typhoon Year-book from 1949 to 1984 and Tropical Cyclone Year-book from 1985 to 2002 extracted from China Meteorological Administration, and the global surface temperature. The main results are as follows: 1) With global warming, the decreasing trend of frequency of typhoon landing in China is weaker than that occurring in the Northwestern pacific, and that average and extreme intensity of typhoon landing in China are both lessening, especially the later, but decreasing trend are weaker than that of typhoon occurring in the Northwestern pacific. In the global warming period of 1968—2002, the landing position of typhoon landing in China situated toward the middle of China and the position of typhoon in the Northwestern Pacific has the trend to the north when it is strongest during its life. 2) The formation potential area of typhoon in the Northwestern Pacific is closed to the zero vertical zonal wind shearing regions and the negative ones, in the same time, the zero line of vertical zonal wind shear is closed to shear line of between east wind and west wind in 850hp and the west of zero wind shear line is in favor of tropical cyclogenesis because of west wind in bottom level and east wind in upper level, that is to say that the wind shear value of the west of zero wind shear line is negative and that topical cyclones have a tendency to occurin the negative vertical wind shear environment, and the east of zero wind shear line, vice verse. 3) The negative or weak wind shear is beneficial to typhoon development, while the great positive one is adverse to typhoon development;in the same time, vertical wind shear has a delay effect of -1.25-5.5 day on the strongest intensity in typhoons’ life, and the delay time has a weak ascending trend in the period of 1951—1977 and a weak decreasing trend in the period of 1978—2002.更多还原