【作者】 苏丽欣；

【导师】 周锁铨； 余锦华；

【作者基本信息】 南京信息工程大学 ， 气候系统与全球变化， 2007， 硕士

【摘要】 本文利用NCEP／NCAR每6h一次和月平均的再分析资料、《热带气旋年鉴》和美国联合台风警报中心(JTWC)热带气旋资料，分析了环境风垂直切变对西北太平洋热带气旋(Tropical Cyclone，简称TC)强度影响的年际和年代际变化；分别从环境风垂直切变、SST、低层涡度和对流层中层相对湿度这四个因子，分析了近十年来西北太平洋海域登陆台风大尺度环境背景场的特征；选取了三个具有代表性的热带气旋个例(碧利斯、珍珠和桑美)，分析在台风整个生命史中热带气旋强度和垂直切变的变化关系；并利用WRF模式对台风Bilis进行了数值模拟。得出如下结论：(1)西北太平洋热带气旋最大风速和环境风垂直切变，在时间上有相反的变化趋势，即当环境风垂直切变小时，TC的最大风速是增大的，弱的环境风垂直切变有利于TC强度的增大。(2)西北太平洋热带气旋达到极大强度之前12h的环境风垂直切变，对TC强度的影响最大，即环境风垂直切变对TC最大强度的影响有12h的时间滞后。两者在年际变化和振荡周期方面的表现也都是一致的。(3)空间上，环境风垂直切变在西北太平洋TC最强的年份表现为：环境风切变值小，在该区域TC发生密集；最弱的年份表现为：环境风切变值大，并且在该区域TC发生稀疏，弱的环境风垂直切变有利于TC强度的增大。(4)在台风的发现点主要集中的区域范围：SST值高于其它区域，都在26.5℃以上；相对涡度几乎都为正值，正的相对涡度有利于台风的发展；对流层中层相对湿度大有利于上升浮力和潜热释放的维持，使热带气旋得以发展。(5) WRF模式对台风路径的模拟具有一定的合理性，对海平面气压的模拟存在着一定的误差；环境风垂直切变和台风强度在时间上有相反的变化趋势，即环境风垂直切变随着时间逐渐减小，而台风强度随着时间逐渐增大。更多还原

【Abstract】 Using tropical cyclone (TC) best track and intensity data of Northwestern Pacific from theJoint Typhoon Warning Center (JTWC) of U.S.A. and the NCEP/NCAR Reanalysis data, theeffects of vertical wind shear on TC intensity of interannual as well as interdecadal variation areexamined. The characteristic of large-scale parameters on TC activity is analyzed from verticalwind shear, SST, low-level relative vorticity and mid-level in troposphere moisture, in recentlydecade landing typhoon of Northwestern Pacific. Three typhoons (Bills, Chanchu, Saomai) arechosen to analyze the effects of vertical wind shear on TC intensity in the whole process. ModelWRF is used to model the typhoon Bilis in statistical analysis. The main results are as follow:(1)There is contrary change trend of time between maximum wind speed and environmentalvertical shear. The weak environmental vertical shear is propitious to the development of tropicalcyclones. (2)The most impact of environmental vertical shear to intensity change of tropicalcyclones, the intensities of which are above tropical storm in the Northwestern Pacific, appears a12 h time lag. (3)In space, when TC is strong the environmental vertical shear is small, and thereare more tropical cyclones; when TC is weak the environmental vertical shear is large, and thereare few tropical cyclones. (4)The SST is higher in more tropical cyclones region than others,besides the SSTs are above 26.5℃; low-level relative vorticity is nearly positive and mid-levelmoisture in troposphere is larger, which are in favor of the development of tropical cyclones.(5)It’s reasonable that using Model WRF to model the path of TC, but there are some errors forair pressure on sea level. There is same change trend of time between TC center lower airpressure and environmental vertical shear.更多还原