摘要
2021年7月17~22日,河南省发生了致灾严重的极端暴雨过程,气象观测站最大6日累积降水量为1122.6 mm(鹤壁市),最大小时雨强高达201.9 mm(郑州市),突破了中国内陆小时雨强历史纪录.利用气象雨量站、探空和多普勒天气雷达等观测资料以及ERA5再分析资料对极端暴雨概况和多尺度特征进行了初探.结果表明,此次极端暴雨过程是在对流层高、中、低层以及中、低纬度多尺度大气系统共同作用,并叠加地形影响下产生的:(1)西南季风将南海的水汽向西北太平洋输送并经由热带气旋“烟花”向北抽吸,西北太平洋上的水汽经“烟花”北部的偏东低空急流和异常偏北偏强的副热带高压西南缘的东南气流向河南输送;这条异常的东进河南的热带气旋远距离接力水汽输送通道导致河南可降水量正异常.(2)对流层高层,河南位于短波槽前辐散区;对流层低层,河南及附近为低涡或倒槽影响,这些均有利于低层大气的辐合和上升.此外,伏牛和太行等山脉对水汽的汇聚和对低层偏东或东南气流的抬升有作用.(3)副热带高压和异常偏强的大陆高压连成“高压坝”,阻碍了中高纬度冷空气南下,郑州极端暴雨发生在暖湿层深厚的环境场中,降水系统呈现低质心热带型雷达回波特征.在郑州降水最为集中的2日内,新生对流不断从东南、南或西南方向并入团状的对流主体,使得中尺度对流系统长时间维持.
During July 17–22, 2021, a disastrous extreme rainfall event occurred in Henan Province, China, with the maximum 6-day accumulated rainfall obtained from meteorological observations being 1122.6 mm(Hebi City). The maximum hourly rainfall reached 201.9 mm(Zhengzhou city), which broke the record in the inland of China. The daily rainfall of 1/6 of the national rain gauge stations in Henan Province exceeded their respective records. In this study, a comprehensive review and a preliminary investigation on the multi-scale atmospheric processes are conducted by using rain gauge observations,sounding data, Doppler weather radar observations and the ERA5 reanalysis data. Results show that this extreme rainfall event was caused by the joint effect of multi-scale atmospheric systems in the middle and low latitudes, and the effect of local topography:(1) The western Pacific subtropical high is abnormally northerly and strong, as compared with the mean circulation in July during the 30-year period of 1991–2020. It prevented the tropical cyclone “In-fa” from moving northward, and was conducive to the westward movement of “In-fa” along its southern periphery. An easterly low-level jet formed between the subtropical high and “In-fa”, which strengthened the water vapor transport to East China.(2) The water vapor was transported from the South China Sea to the Northwest Pacific by the southwest monsoon, and then was carried northwards by the tropical cyclone “In-fa”. The water vapor over the Northwest Pacific was transported to Henan Province by the easterly jet on the north of “In-fa” and the southeast flow around the southwestern periphery of the western Pacific subtropical high. This abnormal remote water vapor transport associated with the tropical cyclone caused a positive anomaly in precipitable water in Henan.(3) In the upper troposphere, the location of Henan Province was in front of an upper-troposphere trough. In the lower troposphere, there was a low-level vortex or an inverted trough over Henan and its periphery. The synoptic conditions over Henan were conducive to the convergence and upward motion of lowertropospheric atmosphere. In addition, the Funiu and Taihang mountain ranges favored the convergence of water vapor and the uplift of the approaching easterly or southeasterly airflow.(4) The subtropical high and the abnormally strong continental high connected and formed a “high-pressure dam”, which prevented mid-latitude cold air from moving southward. The extreme rainfall in Zhengzhou occurred in a warm-humid environment which resulted in a low-centroid precipitation resembling tropical precipitation. During the two days with the heaviest rainfall in Zhengzhou, convection was initiated continuously and merged into the main convective cluster from the southeast, south and southwest respectively, which helped maintain the mesoscale convective system in Henan for a long time.
作者
梁旭东
夏茹娣
宝兴华
张霞
王新敏
苏爱芳
符娇兰
李浩然
吴翀
于淼
胡皓
杨俊
刘璐
徐洪雄
祝从文
刘伯奇
胡宁
王晓芳
陈国民
陈丽娟
Xudong Liang;Rudi Xia;Xinghua Bao;Xia Zhang;Xinmin Wang;Aifang Su;Jiaolan Fu;Haoran Li;Chong Wu;Miao Yu;Hao Hu;Jun Yang;Lu Liu;Hongxiong Xu;Congwen Zhu;Boqi Liu;Ning Hu;Xiaofang Wang;Guomin Chen;Lijuan Chen(State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China;Henan Meteorological Observatory,Zhengzhou 450003,China;National Meteorological Center,Beijing 100081,China;Institute of Heavy Rain,China Meteorological Administration,Wuhan 430074,China;Shanghai Typhoon Institute of China Meteorological Administration,Shanghai 200030,China;National Climate Center,Beijing 100081,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2022年第10期997-1011,共15页
Chinese Science Bulletin
基金
中国气象局创新发展专项(CXFZ2022J014)
国家自然科学基金(42030610,41775002)
北京市自然科学基金(8222079)
灾害天气国家重点实验室基本科研业务费资助。
关键词
极端降水
河南
大尺度环流
中尺度对流
热带气旋
extreme rainfall
Henan
large-scale circulation
mesoscale convection
tropical cyclone
