Analysis of the Causes of Typhoon"Chaba"Heavy Precipitation Under Strong Southwest Monsoon Background
-
摘要: 基于中国气象局热带气旋最佳路径数据集、地面自动站雨量数据和ERA5再分析资料,分析了2203号台风“暹芭”给华南造成大范围持续性强降水的成因。结果表明:(1)“暹芭”与2022年最强盛的西南季风长时间联结,在与季风相互作用的过程中获得了持续不断的水汽和不稳定能量供应。(2)异常加强的高层出流叠加在异常加强的低空的西南急流之上,形成强烈的耦合和抽吸作用,造成低层强烈的辐合和上升运动。(3)低空西南急流穿越大陆暖气团获得增温,向广东输送强暖平流;强烈的上升运动将低层的对流不稳定向上层输送,导致对流不稳定层增厚,同时假相当位温平流随高度减弱也使得局地对流不稳定性增强,二者共同导致了广东地区大气不稳定层结长时间维持。(4)“暹芭”登陆后,低层气流受山脉引导和阻挡而迅速辐合抬升,产生的次级环流有利于局地涡度增长和暴雨发生。另外,较小的环境风垂直切变使得“暹芭”登陆后高层暖心结构仍不消失,使高空形成辐散流场,也有利于强降水发生。Abstract: Based on the best tropical cyclone track data provided by China Meteorological Administration, rainfall observations data and ERA5 reanalysis data, the causes of large-scale sustained heavy rainfall caused by Typhoon 2203 Chaba in South China were analyzed. The results show that: (1) Chaba is connected with the strongest Southwest monsoon in 2022 for a long time, and obtains continuous water vapor and unstable energy supply in the process of interacting with the monsoon. (2) The abnormally strengthened upper level outflow superimposed on the abnormally strengthened lower level southwest jet, forming a strong coupling and suction effect, resulting in strong convergence and upward movement at the lower level. (3) The low-level southwest jet passes through the continental warm air mass and is heated, transporting strong warm advection to Guangdong; The strong upward movement transported the convective instability from the lower layer to the upper layer, which resulted in the thickening of the convective instability layer, and the weakening of the pseudo equivalent temperature advection with height also resulted in the strengthening of the local convective instability, which together led to the long-term maintenance of the atmospheric instability stratification in Guangdong.(4) After the landfall of Chaba, the low-level air flow was guided and blocked by mountains, and the secondary circulation generated was conducive to the local vorticity growth and the occurrence of heavy rain. In addition, the small environmental vertical wind shear makes the high-level warm core structure still not disappear after the landfall of Chaba, forming a divergence flow field in the upper air, which is also conducive to the occurrence of heavy precipitation.
-
Key words:
- tropical cyclones /
- monsoon /
- high level outflow /
- convective instability
-
-
[1] ZHANG Q, WU L, LIU Q. Tropical cyclone damages in China 1983—2006[J]. Bull Amer Meteor Soc, 2009, 90(4): 489-496. [2] 陈超, 卢山, 任志杰, 等. 强西南季风背景下1311号台风"尤特" 的暴雨特征分析[J]. 广东气象, 2015, 37(2): 13-17. [3] 吴天贻, 周玉淑, 王咏青, 等. 两次不同季风强度背景下的西行台风登陆过程降水特征对比分析[J]. 大气科学, 2021, 45(6): 1 173-1 186. [4] 程正泉, 陈联寿, 李英. 登陆热带气旋与夏季风相互作用对暴雨的影响[J]. 应用气象学报, 2012, 23(6): 660-671. [5] 卢山, 吴乃庚, 薛登智. 南海季风槽影响下热带气旋暴雨增幅的研究[J]. 气象, 2008, 34(6): 53-59. [6] 王慧, 丁一汇, 何金海. 西北太平洋夏季风的变化对台风生成的影响[J]. 气象学报, 2006, 64(3): 345-356. [7] 吴恒强. 影响广西的热带气旋与热带季风的某些关系[J]. 气象, 2002, 28(9): 27-32. [8] 丁一汇, 刘月贞. 7507号台风中水汽收支的研究[J]. 海洋学报, 1986, 8(3): 291-301. [9] 姚胜芳, 唐文, 何慧, 等. 西南季风和热带气旋耦合的暴雨过程诊断分析[J]. 海洋预报, 2008, 25(1): 88-94. [10] 王黎娟, 高辉, 刘伟辉. 西南季风与登陆台风耦合的暴雨增幅诊断及其数值模拟[J]. 大气科学学报, 2011, 34(6): 662-671. [11] 林爱兰, 万齐林, 梁建茵, 等. 热带西南季风对0214号热带气旋"黄蜂" 的影响[J]. 气象学报, 2004, 62(6): 841-850. [12] 李英, 陈联寿, 徐祥德. 水汽输送影响登陆热带气旋维持和降水的数值试验[J]. 大气科学, 2005, 29(1): 91-98. [13] MENG W, WANG Y. A diagnostic study on heavy rainfall induced by landfalling Typhoon Utor (2013) in South China: 2. Postlandfall rainfall[J]. J Geophys Res: Atmos, 2016, 121(21): 12 803-12 819. [14] 黄燕燕, 蒙伟光, 冯业荣, 等. 华南登陆台风降水不对称性及持续性问题[J]. 气象, 2023, 49(4): 385-399. [15] 梁建茵, 吴尚森, 游积平. 南海夏季风的建立及强度变化[J]. 热带气象学报, 1999, 15(2): 97-105. [16] 程正泉. 登陆台风与环境因子相互作用对暴雨的影响研究综述[J]. 广东气象, 2008, 30(5): 4-7. [17] 肖婷, 杨怀滨, 张兰. 两个登陆粤西的相似台风降水成因分析[J]. 广东气象, 2024, 46(4): 15-19. [18] 程正泉, 陈联寿, 李英. 登陆台风降水的大尺度环流诊断分析[J]. 气象学报, 2009, 67(5): 840-850. [19] 程正泉, 林良勋, 杨国杰, 等. 超强台风威马逊快速增强及大尺度环流特征[J]. 应用气象学报, 2017, 28(3): 318-326. [20] 吕心艳, 董林, 高拴柱. 台风"米克拉" 在台湾海峡南部快速增强的原因分析[J]. 气象学报, 2023, 81(6): 866-878. [21] 程正泉, 林良勋, 沙天阳, 等. "尤特"特大暴雨过程的热力条件分析[J]. 气象, 2014, 40(12): 1 507-1 512. [22] 周芯玉, 程正泉, 涂静, 等. 台风艾云尼非对称降水及动热力结构演变特征分析[J]. 气象学报, 2020, 78(6): 899-913. [23] 程正泉, 陈联寿, 李英. 地形作用对登陆台风螺旋雨带的影响[C]//第27届中国气象学会年会灾害天气研究与预报分会场论文集. 北京: 中国气象学会, 2010. [24] 陈联寿, 丁一汇. 西太平洋台风概论[M]. 北京: 科学出版社, 1979. [25] 颜玲, 周玉淑, 王咏青. 相似路径台风Soudelor (1513)与Matmo (1410)登陆前后的降水分布特征及成因的对比分析[J]. 大气科学, 2019, 43(2): 297-310. -