2022年9月台风“梅花”引发烟台暴雨的多尺度特征分析

Multi-Scale Characteristics of Extreme Rainstorm Caused by Typhoon “Muifa” in Yantai in September 2022

摘要: 利用欧洲中心再分析数据、逐时自动气象站降雨量等资料，从水汽条件、动力条件、热力条件等重要物理量场对2022年9月14~16日由台风“梅花”引起的烟台历史极端暴雨的多尺度特征进行研究。结果表明：(1) 此次过程整层水汽深厚，一是台风倒槽携带大量水汽，偏东南急流沿副热带高压底后部气流向西北偏北输送。二是台风登陆北上，台风主体从海上携带大量水汽，东南急流头部在暴雨区形成强烈的水汽辐合区，产生大暴雨；(2) 低空急流把大量水汽和不稳定能量向降水区输送，也有利于对流不稳定层结的建立和维持，触发不稳定能量释放；同时低层东南风急流正好位于高空急流入口区右侧，低层辐合、高层辐散，高低空急流耦合抽吸作用，也为降水产生提供了有利动力条件；(3) 此次降水有水汽先行、东南急流滞后的特征；(4) 随着台风北上，由于冷空气的作用破坏了热带气旋的对称结构，造成变性，使降水由稳定性降水向对流性降水转变。干冷空气由台风西侧侵入台风环流内部，弱的冷空气有利于斜压锋生，产生不稳定能量，对降水有利。

Abstract: Using data from the European Center for reanalysis and hourly automated weather station precipitation, this study investigates the multi-scale characteristics of the historically extreme rainstorm in Yantai caused by Typhoon “Muifa” from September 14 to 16, 2022, by analyzing key physical fields such as moisture, dynamic, and thermodynamic conditions. The results indicate that: (1) The entire atmospheric column was characterized by deep moisture during this event. First, the typhoon inverted trough transported substantial moisture, with a southeasterly low-level jet conveying it northwestward to northward along the rear of the subtropical high. Second, as the typhoon made landfall and moved northward, its circulation carried abundant moisture from the ocean. The leading edge of the southeasterly jet formed an intense moisture convergence zone over the rainstorm area, resulting in heavy precipitation. (2) The low-level jet transported both ample moisture and unstable energy into the precipitation area, facilitating the establishment and maintenance of convectively unstable stratification and triggering the release of unstable energy. Simultaneously, the low-level southeasterly jet was located to the right of the entrance region of the upper-level jet. The coupling of low-level convergence and upper-level divergence, along with the pumping effect of the coupled low- and upper-level jets, provided favorable dynamic conditions for precipitation. (3) The precipitation event was characterized by moisture arriving ahead of the southeasterly jet. (4) As the typhoon moved northward, the intrusion of cold air disrupted the symmetric structure of the tropical cyclone, leading to its extratropical transition. This caused a shift from stable to convective precipitation. The intrusion of dry, cold air into the typhoon’s circulation from the west promoted weak baroclinicity and frontogenesis, generating unstable energy that was conducive to precipitation.