中文摘要：

文中用正压原始方程模式和理想初始场研究了随机分布的小尺度涡度场对台风路径的作用。在模式初始场上,有一个理想的副热带高压脊、一个台风和一个随机生成的小尺度涡度场。设计实施两组试验,记为试验A和试验B,积分时间为56 h。每个试验的初始场上各有100个随机分布的小尺度涡。除了小尺度涡的空间位置不同以外,两组试验其余的试验条件全部相同。模式积分的结果指出：小尺度涡不同的空间分布可以引起台风外围水平风速的差异,进而改变台风环境引导流的强度。在24、36和48小时,试验A沿东西方向环境引导流分别为7.8、8.2和8.7 m/s,24-48小时平均值为8.2 m/s,沿南北方向环境引导流分别为0.9、1.8和2.5 m/s,24-48小时平均值为2.1 m/s;试验B沿东西方向分别为8.3、9.5和9.7 m/s,24-48小时平均值为9.5 m/s,沿南北方向分别为2.3、2.3和5.9 m/s,24-48小时平均值为3.4 m/s。环境引导气流强度的不同导致未来台风中心位置的不同。两组不同的初始随机涡度场可以引起48 h以后台风中心相距约120 km。副热带高压与台风相互作用的动力学表明：当初始台风位于副热带高压脊与赤道之间时,局域的绝对涡度梯度与台风传播的关系是由若干个不规则的散布点表征的。引进随机涡度场以后,副热带高压脊、台风和小尺度涡旋三者的共同作用使得绝对涡度梯度与台风传播之间的关系复杂化,除了会出现不规则散布点的特征外,还可显示出两者之间的高相关特征。

英文摘要：

Impacts of small-scale vortices on tropical cyclone（TC） track in a three component system（an idealized subtropical high ridge,a TC,and small-scale vortices） were examined numerically using a barotropic primitive equation model and idealized initial fields.Two small-scale vorticity fields were generated stochastically.In the two fields,the number,size,structure,as well as the total kinetic energy of the small-scale vortices are the same,except the coordinates of the small scale vortex centers distributed stochastically are different.Two experiments,named ExpA and ExpB,with 56-h,integration time are performed. Comparison of the integration outputs from the two experiments indicates that the various small-scale vorticity field involved could produce both the various horizontal wind in the TC outer area and the various intensity of the environmental steering for TC.The values of the environmental current velocity along east-west direction are 7.8,8.2,and 8.7 m/s in ExpA and 8.3,9.5,and 9.7 m/s in ExpB at t = 24,36,and 48 h,respectively.The values along south-north direction are 0.9,1.8,and 2.5 m/s in ExpA and 2.3,2.3,and 5.9 m/s in ExpB,respectively.The various intensity of the environmental steering could lead to various TC center positions,for example, the difference between the coordinates of TC centers in the two experiments reaches 120 km at t = 48 h,which is about 56%of the prediction error of TC track in the northwestern Pacific region derived from eight operational models. Dynamics of the interplays between a subtropical high ridge and a TC in previous studies has shown that when the TC located equatorward of the subtropical ridge,the relationship between the TC propagation and the local absolute vorticity gradient consists of points scattered around their mean value.After introducing the stochastic vorticity field into the model,the interplays among the subtropical high ridge,the TC,and small scale vortices might make the relationship more complex,that is,besides the scattered points mentioned above,