台风“珍珠”螺旋雨带的数值模拟与诊断分析

利用1°×1°的NCEP/NCAR再分析资料,应用非静力中尺度模式WRF对0601号台风＂珍珠＂进行数值模拟,研究暴雨的成因以及螺旋雨带内部结构特征。数值模拟结果表明,台风中的气旋式涡度、垂直运动、动量和热量都集中在螺旋雨带中。进一步研究指出,螺旋雨带上空高层的强辐散与中低层的强辐合相配合产生的强烈＂抽吸作用＂、螺旋雨带两侧的干中心挤压螺旋雨带产生的＂毛细效应＂都导致了低层高湿空气加速向上输送,有利于对流的发展,这也是台风螺旋雨带得以维持的主要原因。

Numerical Simulation and Diagnosis Analysis of Spiral Rain Bands in Typhoon "Pearl"

Through utilizing the NCEP/NCAR 1°×1° reanalysis data and the none-hydrostatic meso-scale model WRF,numerical simulations of typhoon ＂perl＂（0601） were conducted to investigate the formation of typhoon torrential rain and the structure of spiral rain bands.Simulation results show that the cyclonic vorticity,vertical motion,momentum and heat flux of the typhoon mostly concentrated in spiral rain bands.Further analyses suggest that the coupled with strong convergence below the bands at middle-low levels produced violent ＂pumping＂ effect,and the squeeze of spiral rain bands by dry centers on their both sides generated the ＂capillary effect＂,which accelerated the upward transport of the wet air at low levels,thus favorable for the development of convection.And this is also the major reason for the maintenance of the spiral rain bands.