减弱热带气旋附近的倾斜涡度发展

THE DEVELOPMENT OF SLANTWISE VORTICITY NEAR A WEAKENED TROPICAL CYCLONE

使用WRF有限区域模式对2002年第5号台风(Rammasun)减弱后在长白山脉诱生新涡旋产生复合系统的过程进行了60h的模拟。通过对模拟结果的倾斜涡度发展分析,揭示了当减弱的热带气旋移近较高大山脉时,通过与环境场的相互作用可以使空气产生沿倾斜等熵面的下滑运动。在此基础上,热带气旋减弱引起的风的垂直切变的改变可以引起垂直涡度的发展从而诱生新的涡旋中心。

By using the WRY mesoscale model, a 60-h simulation is performed to reproduce the generation of a vortex that linked to a weakened Tropical Cyclone（TC） Rammasun（2002） near the Changbai Mountain. The analysis of the simulation, according to the theory of Slantwise Vorticity Development （SVD） proposed by Wu et al., indicates that, approaching high mountains, the TC interacts with the environment to force air masses to slide down slantwise isentropic surfaces. Furthermore, the change of the vertical wind shear due to TC＇s weakening can result in the development of vertical vorticity and the occurrence of a new vortex center.