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气象:2022,48(5):545-555
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对流层高层冷涡对“21·7”河南持续性极端暴雨影响分析
蔡芗宁,陈涛,谌芸,符娇兰,胡宁
(国家气象中心,北京 100081;中国气象科学研究院灾害天气国家重点实验室,北京 100081;南方海洋科学与工程广东省实验室(珠海),珠海 519082)
Dynamic Impact of Upper Tropospheric Cold Low on Persistent Extreme Rainstorm of Henan During 17-22 July 2021
CAI Xiangning,CHEN Tao,CHEN Yun,FU Jiaolan,HU Ning
(National Meteorological Centre, Beijing 100081;State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081;Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082)
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投稿时间:2021-11-01    修订日期:2022-02-18
中文摘要: 2021年7月17—22日河南出现历史罕见持续性特大暴雨,期间我国东部海区上空的对流层高层冷涡(upper tropospheric cold low,UTCL)与河南降水几乎同步增强,对降水天气形势发展存在影响。强降水过程期间河套高空短波槽、黄淮高压脊、UTCL以及日本海阻塞高压形成准静止波列,环流系统异常稳定,由于UTCL在我国东部海区上空停滞,导致西风急流在河南及其以东地区形成大尺度持续性辐散分流。河南暴雨高空辐散区的建立和增强与UTCL西侧的西北风急流增强直接相关;UTCL东侧急流增强了台风烟花的高层流出,有利于台风加强进而影响河南暴雨区水汽输送;UTCL引起的高空下沉运动增强了副热带高压的稳定性,间接增强了从东部海区向河南的偏东风水汽输送。UTCL数值预报不确定性较大,随着预报时效临近,UTCL环流中心不断向偏北方向调整、强度增强,对应河南暴雨落区有向东调整的趋势。集合预报成员中强、弱UTCL环流分组对比表明,较强的UTCL环流有利于增强河南上空的反气旋性辐散流出,对降水增强较为有利,基于集合预报敏感性的诊断进一步证实了上述结论。
Abstract:Extreme rainstorms struck Henan Province during 17 to 22 July 2021. With the enhancing of the upper tropospheric cold low (UTCL) over the China East Sea, the precipitation in Henan burst almost simultaneously, indicating that UTCL has potential impact on the development of the precipitation. From 19 to 22 July, the upper-level short-wave trough over Hetao Area, the high ridge over Huanghuai Region, UTCL and the blocking high over Japan Sea formed a wave train which led to the almost stationary synoptic circulations. During the heavy rainfall, UTCL stagnated over the eastern seas of China, resulting in large-scale divergence in westerly jet over Henan Provice and its eastern region. The establishment and enhancement of the upper-level divergence over Henan was clearly related to the acceleration of northwest jet on the west part of UTCL. Meanwhile, south flow jet on the eastside of UTCL enhanced the upper-level outflows of Typhoon In-fa, which was conducive to the growth of In-fa’s circulation and the water vapor transportation to the rainstorm area of Henan. On the other hand, the upper-level sinking caused by UTCL enhanced the stability of the subtropical high, and also enhanced the low-level water vapor transportation from the East China Sea to Henan. The UTCL showed obvious forecast uncertainty. From adjacent forecast cycles, the center of UTCL continued to adjust to the north, intensifying and the heavy rainfall area in Henan also tended to adjust to the east direction. The comparison between strong and weak UTCL circulation among ensemble members shows that, strong UTCL circulation was conducive to enhance the anticyclonic divergent outflow over Henan and was more conducive to the enhancement of precipitation in Henan, which has been also proved by ensemble sensitivity analysis.
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基金项目:国家重点研发计划(2019YFC151040),灾害天气国家重点实验室开放课题(2021LASW-A16)共同资助
引用文本:
蔡芗宁,陈涛,谌芸,符娇兰,胡宁,2022.对流层高层冷涡对“21·7”河南持续性极端暴雨影响分析[J].气象,48(5):545-555.
CAI Xiangning,CHEN Tao,CHEN Yun,FU Jiaolan,HU Ning,2022.Dynamic Impact of Upper Tropospheric Cold Low on Persistent Extreme Rainstorm of Henan During 17-22 July 2021[J].Meteor Mon,48(5):545-555.