“格美”台风残涡对湖南溆浦极端强降水影响分析

Analysis of the impact of extreme heavy precipitation in Xupu under the influence of “Gaemi” typhoon residual vortex

摘要

受 2024 年第 3 号台风“格美”残涡影响，当年 7 月 28 日湖南溆浦出现一次极端强降水过程，小时雨量达 120.1 mm，突破当地历史记录。为了深入认识此次极端强降水的发生发展机制，提高极端强降水的预警水平，综合利用多源观测资料和 ERA5 再分析资料，对极端强降水的成因和微物理特征开展了研究。结果表明：在有利的层结、能量和水汽条件下，台风残涡南侧的西南气流水汽输送和西侧的偏北风水汽输送在暴雨区汇合，为极端强降水的发生提供有利的环流背景和环境条件。极端强降水由一个准静止 β 尺度中尺度对流系统 (MCS) 造成，在雷达回波图上该 MCS 表现为鑲嵌在混合云回波中的两个强风暴单体及其合并过程，属于低质心、高效率的暖云降水回波，低层辐合、中高层辐散的垂直结构特征有利于上升运动的维持。中尺度涡旋 (MV) 与次级环流的配合加强了风暴内的垂直上升运动，有利于将低层的暖湿空气输送到上升气流中，产生和维持极端降雨率，导致极端强降水的形成。极端小时降雨时段雨滴直径增大、浓度增加，以暖雨碰并增长为主，极端降雨主要与直径>1 mm 的雨滴贡献有关，其中直径在 (1, 3] mm 区间的雨滴降雨贡献率约占 80%。最后，给出了导致本次极端强降水的概念模型，作为此类天气分析和预报的参考。

Abstract

Affected by the residual vortex of Typhoon “Gaemi” on July 28 2024, an extreme heavy precipitation event occurred in Xupu, Hunan Province, with an hourly rainfall of 120.1 mm·h^-1, breaking the local historical record. To get a deep understanding of the development mechanism of HER and improve the analysis and forecasting ability of EHR, multi-source observations and ERA5 reanalysis data are comprehensively used to analyze the causes and microphysical characteristics of EHR. The results show that under the favorable environmental conditions of stratification, energy, and water vapor, the convergence between the southwest moisture transport from the south side of the typhoon residual vortex and the northerly moisture transport from the west side of the residual vortex triggered the occurrence of extreme heavy precipitation. The EHR is caused by a quasi-stationary β-scale Mesoscale Convective System (MCS). On the radar echo map, this MCS shows as the merging process of two strong storm cells embedded in the mixed cloud echo, which belongs to the low-centroid, high-efficiency warm cloud precipitation echo. The vertical structure characterized by low-level convergence and mid-high-level divergence is conducive to the maintenance of ascending motion. The maintenance of the coupling situation between mesoscale vortex (MV) and secondary circulation strengthens the vertical upward movement within the storms, facilitating the transport of low-level warm and humid air to the updrafts, consequently generating and maintaining extreme rainfall rates, and leading to the occurrence of EHR. During EHR, the diameter and concentration of raindrops increase, mainly due to the collision and growth of warm rain. The rainfall is primarily contributed by raindrops with diameters greater than 1 mm, among which the contribution rate of rainfall in the range of (1, 3] mm accounts for about 80%. Finally, a conceptual model of the EHR was summarized, which provides a reference for future weather analysis and forecasting research.

关键词

极端小时降雨 / 微物理特征 / 中尺度涡旋 / 次级环流

Key words

extreme hourly precipitation / microphysical characteristics / mesoscale vortex (MV) / secondary circulation

参考文献

[1] 丁一汇. 2015.论河南“75.8”特大暴雨的研究:回顾与评述[J].气象学报,73(3):411-424.

[2] Ding Y H. 2015. On the study of the unprecedented heavy rainfall in Henan Province during 4-8 August 1975: Review and assessment [J].Journal of Meteorology,73(3):411-424 (in Chinese). doi:10.11676/qxxb2015.067

[3] 蒋亚平,覃皓,黄妮,等. 2025.广西西南部一次极端暴雨过程成因分析[J].高原山地气象研究,45(1):113-121.

[4] Jiang Y P, Qin H, Huang N, et al. 2025. Cause analysis of an extreme rainstorm in southwest Guangxi [J].Plateau and Mountain Meteorology Research,2025,45(1): 113-121 (in Chinese). doi:10.3969/j.issn.1674-2184.2025.01.013

[5] 罗菊英,张家国,许冠宇,等. 2023. 2020 年夏季鄂西南一次极端暴雨过程 成因分析[J].沙漠与绿洲气象,17(2):26-35.

[6] Luo J Y, Zhang J G, Xu G Y, et al. 2023. Analysis of the causes of an extreme rainstorm in western Hubei in the summer of 2020 [J].Desert and Oasis Meteorol- ogy,17(2):26-35 (in Chinese). doi:10.12057/j.issn.1002-0799.2023. 02.004

[7] 骆凯,李耀东,秦丽. 2010.一次华北暴雨过程的数值模拟及水汽过程分析[J].暴雨灾害,29(4):307-314.

[8] Luo K, Li Y D, Qin L. 2010. Numerical simulation and process analysis of moisture flux on the rainstorm pro- cess in North China [J].Torrential Rain and Disasters,29(4):307-314 (in Chinese).

[9] 闵爱荣,廖移山,张文. 2024. 2021 年 4-10 月我国主要暴雨天气过程简 述[J].暴雨灾害,43(5):617-626.

[10] Min A R, Liao Y S, Zhang W. 2024. Major heavy rainfall events in China from April to October in 2021 [J].Torrential Rain and Disasters,43(5):617-626 (in Chinese). doi:10. 12406/byzh.2024-048

[11] 裴坤宁,王磊,李谢辉,等. 2019.一次变形场背景下的暴雨位涡诊断研究[J].高原气象,38(6):1221-1228.

[12] Pei K N, Wang L, Li X H, et al. 2019. Potential vorticity diagnose on a heavy rainstorm under deformation field [J].Plateau Meteorology,38(6):1221-1228 (in Chinese). doi:10. 7522/j.issn.1000-0534.2019.00021

[13] 冉令坤,李舒文,周玉淑,等. 2021. 2021 年河南"7·20"极端暴雨动、热力 和水汽特征观测分析[J].大气科学,45(6):1366-1383.

[14] Ran L K, Li S W, Zhou Y S, et al. 2021. Observational analysis of the dynamic, thermal, and water vapor characteristics of the "7·20" extreme rain- storm event in Henan Province, 2021 [J].Chinese Journal of Atmo- spheric Sciences,45(6):1366-1383 (in Chinese). doi:10.3878/j.issn. 1006-9895.2109.21160

[15] 沈晓琳,陶亦为,张芳华,等. 2018. 2017 年 4-10 月我国主要暴雨天气过 程简述[J].暴雨灾害,37(2):187-196.

[16] Shen X L, Tao Y W, Zhang F H, et al. 2018. Important heavy rain events in China from April to October in 2017 [J].Torrential Rain and Disasters,37(2):187-196 (in Chinese). doi:10.3969/j.issn.1004-9045.2018.02.011

[17] 王俊,陈宝君,周淑玲,等. 2023.郑州“7·20”特大暴雨雨滴谱特征分析[J].高原气象,42(5):1247-1259.

[18] Wang J, Chen B J, Zhou S L, et al. 2023. Analyzing the characteristics of raindrop size distributions of the“7·20” torrential rain in Zhengzhou on 20 July 2021 [J].Plateau Meteorology,42(5):1247-1259 (in Chinese). doi:10.7522/j.issn. 1000-0534.2022.00089

[19] 王青霞,唐明晖,吴亚昊,等. 2025.基于多源观测资料的长沙“4·29”强对流 天气过程分析[J].暴雨灾害,44(3):309-321.

[20] Wang Q X, Tang M H, Wu Y H, et al. 2025. Analysis of "4·29" severe convective weather event in Changsha based on multi-source observation data [J]. Tor- rential Rain and Disasters,44(3):309-321 (in Chinese). doi:10.12406/ byzh.2024-112

[21] 吴梦雯,罗亚丽. 2019.中国极端小时降水 2010-2019 年研究进展[J].暴 雨灾害,38(5):502-514.

[22] Wu M W, Luo Y L. 2019. Extreme hourly precipitation over China: research progress from 2010 to 2019 [J].Torrential Rain and Disasters,38(5):502-514 (in Chinese). doi:10. 3969/j.issn.1004-9045.2019.05.012

[23] 徐珺,毕宝贵,谌芸,等. 2018. “5.7”广州局地突发特大暴雨中尺度特征及 成因分析[J].气象学报,76(4):511-524.

[24] Xu J, Bi B G, Chen Y, et al. 2018. Mesoscale characteristics and mechanism analysis of the unex- pected local torrential rain in Guangzhou on 7 May 2017 [J].Journal of Meteorology,76(4):511-524 (in Chinese). doi:10.11676/qxxb2018. 016

[25] 俞小鼎,郑媛媛,廖玉芳,等. 2008.一次伴随强烈龙卷的强降水超级单体 风暴研究[J].大气科学,32(3):508-522.

[26] Yu X D, Zheng Y Y, Liao Y F, et al. 2008. Observational investigation of a tornadic heavy precip- itation supercell storm [J].Chinese Journal of Atmospheric Sciences, 32(3):508-522 (in Chinese). doi:10.3878/j.issn.1006-9895.2008.03. 08

[27] 俞小鼎. 2013.短时强降水临近预报的思路与方法[J].暴雨灾害,32(3): 202-209.

[28] Yu X D. 2013. Nowcasting thinking and method of flash heavy rain [J].Torrential Rain and Disasters,32(3):202-209 (in Chi- nese). doi:10.3969/j.issn.1004-9045.2013.03.002

[29] 翟丽萍,梁依玲,周云霞,等. 2024.桂林“5.22”极端强降雨过程的观测分 析[J].暴雨灾害,43(3):313-321.

[30] Zhai L P, Liang Y L, Zhou Y X, et al. 2024. Observation analysis of "5.22" extreme rainfall event in Guilin [J].Torrential Rain and Disasters,43(3):313-321 (in Chinese). doi:10.12406/byzh.2023-141

[31] Davies-Jones R. 1984. Streamwise vorticity: The origin of updraft ro- tation in supercell storms [J].Journal of the Atmospheric Sciences, 41(20):2991-3006. doi:10.1175/1520-0469(1984)041<2991:SVTOO U>2.0.CO;2

[32] James P M, Reichert B K, Heizenreder D. 2018. NowCastMIX: Automat- ic integrated warnings for severe convection on nowcasting time scales at the German weather service [J].Weather and Forecasting, 33(5):1413-1433. doi:10.1175/WAF-D-18-0038.1

[33] Klemp J B. 1987. Dynamics of tornadic thunderstorms [J].Annual Re- view of Fluid Mechanics,19:369-402. doi:10.1146/annurev.fl.19. 010187.002101

[34] Kumjian M R. 2013a. Principles and applications of dual-polarization weather radar. Part I: Description of the polarimetric radar variables [J].Journal of Operational Meteorology,1(19):226-242. doi:10.15191/ nwajom.2013.0119

[35] Kumjian M R. 2013b. Principles and applications of dual-polarization weather radar. Part II: Warm- and cold-season applications [J].Jour- nal of Operational Meteorology,1(20):242-264. doi:10.15191/nwa- jom.2013.0120

[36] Li M X, Luo Y L, Zhang D L, et al. 2021. Analysis of a record-breaking rainfall event associated with a monsoon coastal megacity of south China using multisource data [J].IEEE Transactions on Geoscience and Remote Sensing,59(8):6404-6414. doi:10.1109/TGRS.2020. 3029831

[37] Lu X Q, Yu H, Ying M, et al. 2021. Western North Pacific tropical cy- clone database created by the China Meteorological Administration [J].Advances in Atmospheric Sciences,38(4):690-699. doi:10.1007/ s00376-020-0211-7

[38] Nielsen E R, Schumacher R S. 2020a. Observations of extreme short-term precipitation associated with supercells and mesovortexs [J].Month- ly Weather Review,148(1):159-182. doi:10.1175/MWR-D-19-01 46.1

[39] Nielsen E R. Schumacher R S. 2020b, Dynamical Mechanisms Support- ing Extreme Rainfall Accumulations in the Houston “Tax Day” 2016 Flood [J].Monthly Weather Review,148(1):83-109. doi:10.1175/ MWR-D-19-0206.1

[40] Rotunno R, Klemp J B. 1985. On the rotation and propagation of simulat- ed supercell thunderstorms [J].Journal of the Atmospheric Sciences, 42(3):271-292. doi:10.1175/1520-0469(1985)042<0271:OTRAPO> 2.0.CO;2

[41] Ryzhkov A V, Zhuravlyov V B, Rybakova N A, 1994. Preliminary results of X-band polarization radar studies of clouds and precipitation [J].Journal of Atmospheric and Oceanic Technology, 11(1): 132-139. doi:10.1175/1520-0426(1994)011<0132:PROXBP>2.0.CO;2

[42] Schumacher R S, Johnson R H. 2005. Organization and environmental properties of extreme-rain-producing mesoscale convective syste- ms [J].Monthly Weather Review,133(4):961-976. doi:10.1175/ MWR2899.1

[43] Schumacher R S. 2017. Heavy Rainfall and Flash Flooding[M].Natural Hazard Science: Oxford Research Encyclopedias, 40 pp. doi:10.1093/ acrefore/9780199389407.013.132

[44] Sui C H, Li X, Yang M J. 2007. On the definition of precipitation efficien- cy [J].Journal of the Atmospheric Sciences,64(12):4506-4513. doi:10.1175/2007JAS2332.1

[45] Terti G, Ruin I, Anquetin S, et al. 2017. A situation-based analysis of flash flood fatalities in the United States [J].Bulletin of the American Me- teorological Society,98(2):333-345. doi:10.1175/BAMS-D-15-002 76.1

[46] Wang X M, Zheng Y G, Fan L M, et al. 2023. The key mesoscale systems and mesoscale vortices of the Henan extreme precipitation in 2021 [J].Sustainability,15(6):4875. doi:10.3390/su15064875

[47] Weisman M L, Klemp J B. 1984. The Structure and classification of nu- merically simulated convective storms in directionally varying wind shears [J].Monthly Weather Review,112(12):2479-2498. doi:10. 1175/1520-0493(1984) 112<2479:TSACON>2.0.CO;2

[48] Zhang W X, Zhou T J. 2020. Increasing impacts from extreme precipita- tion on population over China with global warming [J].Science Bul- letin,65(3):243-252. doi:10.1016/j.scib.2019.12.002

基金资助

湖南省自然科学基金重大项目(2021JC0009)

湖南省重大研发专项(2024AQ2016)

湖南省气象局创新发展专项(CXFZ2025-ZDZX01，CXFZ2026-ZDXM11)