高原低涡结构特征模拟与诊断的初步研究

利用二重嵌套的非静力中尺度数值模式MM5对2005年7月28—29日的一次高原低涡过程进行了数值模拟，并利用模拟结果对此次低涡的结构进行了初步分析。结果表明：MM5模式对此次低涡过程有较好的模拟能力，模拟出的位势高度场分布和涡度场结构与实况基本吻合。此次高原低涡具有同热带气旋相似的涡眼（空心）结构和暖心结构。在流场上，高原低涡在涡眼区下层表现为辐散下沉运动，上层为辐合上升运动；而在涡心四周下层表现为辐合上升运动，上层为辐散下沉运动；在涡度场上，高原低涡下层为正涡度区，上层为负涡度区。

Study of Character Simulation and Diagnoses of Plateau Vortex

By using the two-dimension nested non-hydrostatic meso-scale numerical model MM5, a plateau vortex occurring during July 28 -29, 2005 is simulated, and the structure of the vortex is analyzed on the basis of the simulation results. The results show that the MM5 model has enough ability to simulate the vortex structure. The vortex eye structure and the warm core structure of the plateau vortex are similar to the tropical cyclone. On the flow field, the vortex eye of the plateau vortex in the lower level is divergent downward flows and the upper level is convergent upward flows; and around the vortex core in the lower level is convergent upward flows and the upper level is divergent downward flows. On the vorticity field, the plateau in the lower level is positive vorticity area and the upper level is negative vorticity area.