基于3DVPAS模式模拟的热力扰动在台风涡旋中的螺旋特征分析

Analysis on Spiral Characteristics of Thermal Disturbance in Typhoon Vortex Based on 3DVPAS Model

利用WRF模式模拟了2007年04号台风"万宜"环流,选取发展初期的低层风场作为基本气流代入三维涡旋扰动分析和模拟模式(3DVPAS),模拟分析了理想的热力扰动在该基本气流中的演变特征。结果表明:基本气流的低层流场特征在热力扰动演变过程中起重要作用。虽然发生在不同径向距离处的热力扰动都会导致基本气流偏离静力平衡状态,但在距离涡旋中心较近的地方,静力平衡状态恢复更快。扰动的演变可分为快速调整阶段和准平衡阶段。在快速调整阶段,扰动沿径向内外同时传播,向外传播的扰动逐渐减弱,向内传的扰动不断在台风眼壁附近聚集,经过一段时间的演变,在内聚集的热力扰动开始向外传播,随着时间的发展向外传播的扰动逐渐减弱。同时,伴随着螺旋带的发展及消亡,热力扰动的演变也表现出不对称的结构。

The process of typhoon＂Manyi＂（200704）was simulated by using WRF model.The low-level wind field of early developing Typhoon was selected as the basic flow to add into 3DVPAS,and the evolution of ideal thermal disturbance in the basic flow was simulated and discussed.The results showed that the low-level flow of the basic flow played an important role in the evolution of disturbance,although the thermal disturbance occurred at different radial distances would cause the basic flow to deviate from the static balance state,the static balance state can recover faster in the vicinity of the vortex center.The evolution of disturbance can be divided into rapid adjustment stage and quasi-equilibrium stage.In the rapid adjustment stage,the disturbance propagated along the radial and inner side,but the disturbance of outward propagation gradually weakened.The inward spread of the disturbance constantly concentrated in the eye wall.After a period of evolution,the disturbance began to spread outward,and the disturbance of the external propagation weakened gradually with time.The evolution of disturbance al-so showed asymmetric structure,accompanied with the development and extinction of spiral bands.