台风“莫兰蒂”海陆边界层结构差异性分析

Differential Analysis of Sea-land Boundary Layer Structure of Typhoon Moranti

关键词:  风廓线雷达  台风边界层  最大切向风速高度  入流层高度  湍流

Key words:  wind profile radar  typhoon boundary layer  height of the maximum tangential wind speed  height of the inflow layer  turbulence

摘要:

在超强台风莫兰蒂(1614)系统影响下，主要利用福建沿海风廓线雷达观测资料对“海洋”和陆地下垫面的台风边界层结构差异性进行了详细分析，结果表明，气球探空资料反演的热力学边界层高度和动力学边界层高度存在明显的分离，风廓线雷达风场资料反演最大切向风速高度(Hvtmax)和入流层高度(Hinflow)在晴空天气下具有较高的可靠性，在降雨条件下只能定性反映台风边界层特征。在台风莫兰蒂外雨带(距台风中心200~100km)，“海洋”下垫面的Hvtmax位于Hinflow下方，在外围晴空(距台风中心600~400km)，“海洋”下垫面的Hvtmax和Hinflow处于同一高度水平，而陆地下垫面受摩擦效应影响Hvtmax始终位于Hinflow之上，陆地下垫面的切向风速比“海洋”下垫面的偏小，陆地下垫面的Hvtmax比“海洋”下垫面的偏高。此外，在台风莫兰蒂外围晴空，“海洋”下垫面的湍流活动主要分布在Hinflow上或其下方；而陆地下垫面的湍流活动更强，主要分布在Hvtmax和Hinflow之间，表明在台风边界层高度上下有着复杂的湍流活动。可见，不同下垫面形成不同的台风边界层结构分布特征，这些结果希望能够为评估和改进台风模型中的边界层方案提供有用的信息。

Abstract:

Under the influence of the super typhoon Moranti (1614) system, a detailed analysis was conducted on the differences in typhoon boundary layer structures between the "ocean" and the land underlying surface using observation data from Fujian coastal wind profile radar. The results showed that there was a significant separation between the thermodynamic boundary layer height and the dynamic boundary layer height inverted by sounding radar data, and the maximum tangential wind speed height (Hvtmax) and inflow layer height (Hinflow) inverted by wind profile radar wind field data has high reliability in clear sky weather, and can only qualitatively reflect the characteristics of the typhoon boundary layer under rainfall conditions. In the outer rain belt of Typhoon Meranti (200-100 km from the center of the typhoon),the Hvtmax of the "ocean" surface is located below the Hinflow, in the outer clear sky (600-400 km from the center of the typhoon), the Hvtmax and Hinflow of the "ocean" surface is at the same height level, while the Hvtmax of the land surface is always located above the Hinflow affected by the frictional effect,the tangential wind speed of the land underground surface is smaller than that of the "ocean" underlying surface, and the Hvtmax of the land underground surface is higher than the Hvtmax of the "ocean" underground surface. In addition, on the periphery of Typhoon Meranti, turbulent activity on the underlying surface of the "ocean" is mainly distributed in or below the Hinflow; And the turbulent activity on the underlying surface of the land is stronger, mainly distributed between Hvtmax and Hinflow, there are more complex turbulent activities near the top of typhoon boundary layer. So,It can be seen that different underlying surfaces form different structural distribution characteristics of the typhoon boundary layer, these results hope to provide useful information for evaluating and improving the boundary layer scheme in the typhoon model.