| 摘要: |
| 基于观测和ERA-Interim再分析资料，对2018年8月3—4日云南发生的连续性强降水过程进行诊断分析，发现：强降水发生前，云南位于两高（滇缅高压和位于南海地区的高压）之间的辐合区，台风及青藏高原东侧低涡对两高之间辐合区的正相对涡度输送，促使两高之间辐合区形成低涡；低涡在向南向西移动过程中，其中心自下而上保持西北—东南向倾斜；雨带随低涡切变移动，降水中心和低涡中心基本保持一致；在低层辐合、高层辐散的配置下，强降水中心出现在θse大值区，且与强上升运动大值区相一致；过程期间，云南为净水汽收入，东边界在整个过程中保持水汽收入，西边界和南边界水汽收支则随着低涡的移动在整个过程中出现输入输出反向变化。 |
| 关键词: 低涡；强降水；两高之间辐合区；高原系统；诊断分析 |
| DOI： |
| 投稿时间：2021-01-11 |
| 基金项目:国家自然科学基金:北极涛动对低纬高原地区冬半年降水影响的机理研究（41665005）、高原涡影响下的云南大雨暴雨分布特征及其形成机理研究（41765003）；国家重点研发计划课题（2018YFC1507603）:复杂地形区强降水预报评估与特征分析 |
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| The Diagnostic Analysis for a Low-vortex Heavy Rain Process Occurred in Midsummer over Yunnan Province |
| MA Wenqian,XIANG Ying,NIU Fabao,SUN Jihua,MA Zhimin,PEI Yue |
| (Yunnan Meteorological Observatory,Kunming 650034 , China;Zhaotong Meteorological Observatory of Yunnan Province,Zhaotong 657000 , China) |
| Abstract: |
| Based on observation and ERA-Interim reanalysis data, the diagnostic analysis for a continuous heavy rain occurred over Yunnan Province during Aug. 3 to Aug. 4, 2018 was conducted. Before the heavy rain, Yunnan Province was controlled by the convergence area between two highs (high pressure over Yunnan-Burma and the South China Sea). The positive advection of relative vorticity from the typhoon and the low vortex over the east of the Tibetan Plateau to the convergence area made the convergence area develop into a low vortex. During the westward and southward movement of the low vortex, the center of the low vortex kept northwest-southeast tilting from the low-level troposphere to the middle troposphere. The rain moved along with the shear line of the vortex, and the center of the heavy rain was almost consistent with that of the low vortex. Under the situation of low-level convergence and high-level divergence, the rain occurred in the area with high θse and kept consistent with that of strong upward motion. During the process, there was a net inflow of water vapor over Yunnan Province, and also an inflow at the east boundary. At the west and south boundaries, there was a reverse change in the flow of water vapor as the low vortex moved. |
| Key words: low vortex； heavy rain； the convergence area between two highs； systems over the Tibetan Plateau； diagnostic analysis |
