首页|宜昌市致洪中尺度极端降水成因分析

宜昌市致洪中尺度极端降水成因分析

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  • 国家科技期刊平台
  • NETL
  • NSTL
  • 万方数据
极端降水对河流防洪调控、水库蓄水泄洪等具有重要的影响,研究极端降水成因成为强化区域洪水资源管理的必要环节.基于多源观测资料和ERA5 再分析资料,利用HYSPLIT 后向轨迹模式和锋生强度诊断等方法,对2023 年8 月26 日夜间宜昌市致洪中尺度极端降水成因进行分析.结果表明:① 此次极端降水过程关键影响系统为低空急流、超低空急流、边界层冷空气和中尺度低涡.强降水可以分为中尺度低涡新生、低空急流发展,冷暖对峙、冷锋南下,低涡中心东移3 个阶段.② 此次过程中低层主要有4 条暖湿输送通道,强降水区水汽通量超800 kg/(m·s),可降水量超70 mm.③强降水时段低层相对涡度正值中心与垂直速度负值中心基本重合,加之锋生作用增强,强降水中心低层垂直速度达-7.1 Pa/s.④ 强降水时段,地形过渡带附近形成θse(假相当位温)能量锋区,垂直方向上出现高能舌,800 hPa附近中心强度达360 K以上.⑤ 中尺度地形形成了"西北冷干、东南暖湿"中尺度温湿锋区,并起到了阻挡抬升和触发作用,使强降水出现在山前喇叭口内.研究成果可为汛期区域洪水资源管理策略制定提供依据.
Causes of a flood-causing mesoscale extreme precipitation in Yichang City
Extreme precipitation has an important impact on flood control and water dispatch of rivers and reservoirs.Studying the causes of extreme precipitation is a necessary stage to strengthen regional water resources management.Based on multi-source observation data and ERA5 reanalysis data,using HYSPLIT backward trajectory model and frontogenesis intensity diagno-sis,the causes of a flood-causing extreme heavy precipitation in Yichang City on the night of August 26,2023,were analyzed.The results indicated that:① In this extreme precipitation process,the low-level jet,super low-level jet,boundary layer cold air,and mesoscale vortex were the key influencing systems.The heavy rainfall period could be divided into three stages:the for-mation of the mesoscale vortex and the development of low-level jets,the confrontation between the cold and warm streams and the southward movement of the cold front,and the eastward movement of the vortex center.②There were four main warm and wet transport channels in the middle and lower layers of the process,which made the water vapor flux in the heavy precipitation area o-ver 800 kg/(m·s)and PWV(Precipitable Water Vapor)over 70 mm.③During the heavy rainfall period,the positive vorticity center and the negative velocity center basically coincided,the frontogenesis was enhanced,and the vertical ascending motion was strong,the vertical velocity at the lower level reached-7.1 Pa/s.④ During the heavy rainfall period,the θse energy front zone was formed near the terrain transition zone,the high-energy tongue was formed in the vertical direction,and the center of 800 hPa θse reached over 360 K.⑤ The combination of mesoscale topography and jet stream formed a mesoscale temperature and hu-midity frontal zone of"northwest cold and dry,southeast warm and wet".The terrain played a role in blocking the uplift and trig-gering so that heavy rainfall appeared in the front of the mountain.The research results could provide a basis for formulating re-gional water management strategies during the flood season.

extreme heavy precipitationsuper low-level jetcold air in the boundary layermesoscale frontal zoneinflu-ence of topographyHYSPLIT backward trajectory modelYichang City

成勤、王清龙、孟芳、李芳、彭福强、雷东洋

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三峡国家气候观象台,湖北宜昌 443000

湖北省宜昌市气象局,湖北宜昌 443000

中国地质大学海洋学院,湖北 武汉 430074

极端降水 超低空急流 边界层冷空气 中尺度锋区 地形作用 HYSPLIT后向轨迹模式 宜昌市

湖北省自然科学基金项目三峡局地气候监测项目湖北省气象局科技发展基金项目

2023AFD106SK20230192023Y13

2024

10.16232/j.cnki.1001-4179.2024.07.012

人民长江
水利部长江水利委员会

人民长江

CSTPCD北大核心
影响因子：0.451
ISSN：1001-4179
年,卷(期)：2024.55(7)
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