中文摘要：

利用WRF模式较成功地模拟出2009年发生在西太平洋上的三个台风（“天鹅”、“莫拉克”和“艾涛”）,并在此基础上,对三个台风中的水平涡度、垂直涡度及它们的相互作用进行分析和诊断.结果发现,在这三个台风演变过程中,水平涡度与垂直涡度的合矢量有较固定的模式,在900 hPa以下低层有水平涡度的辐合,900～ 800hPa左右有水平涡管的流出,800～ 700hPa有水平涡管的流入,当有多个风速中心存在时,在风速中心之下有水平涡管向台风中心辐合、之上有自中心向外的辐散.特别是在低层通过涡管形成的垂直环流相互作用,这种环流主要由自西向东、或自东向西的水平涡度矢量构成,其上升支有云和降水产生,多从左台风的东北部流向右台风的西南部.由完全涡度方程分析可见,在850hPa以下的最大风速中心附近有水平涡度向垂直涡度转化,其转化最剧烈的时期与台风的风速增长期一致,涡度平流的作用与之相反,起到减弱台风的作用.800～ 600hPa有垂直涡度向水平涡度转化,低层最大风速之上风速减小.

英文摘要：

Three typhoons,Goni,Morakot and Etau,which were generated in Western Pacific in 2009,are successfully simulated by the WRF model.The horizontal and vertical vorticity and their inteaction are analyzed and diagnosed by using the simulation results.It is shown that their co-vector has a certain pattern in the evolution process of the three typhoons：the horizontal vorticity converges to the tropical cyclone （TC） center below 900 hPa,flows out from it around 900 ～ 800 hPa,and flows in between 800 hPa and 700 hPa.If multiple maximum wind speed centers show up,the horizontal vorticity converges to the center of the typhoon below the maximum wind speed center and diverges from the TC center above the maximum wind speed center.At low levels,the three typhoons interact with each other through vertical circulation generated by the vortex tube.This circulation is mainly generated by the eastward or westward horizontal vorticity vectors.Clouds and precipitation are generated on the ascending branch of the vertical circulation.The vortex tubes often flow toward the southwest of the right TC from the northeast of the left TC.According to the full vorticity equation,the horizontal vorticity converts to the vertical vorticity near the maximum wind speed below 850 hPa,and the period of most intense conversion is consistent with the intensification period of TC,while the vorticity advection is against the intensification.The vertical vorticity converts to the horizontal vorticity from 800 hPa to 600 hPa,and the wind speed decreases above the maximum wind speed at low levels.