“23·8”黑龙江极端强降水过程特征与成因  

Characteristics and Causes of Extreme Heavy Rainfall in Heilongjiang Province During August 2023

作　　者：齐铎[1] 王承伟[1] 白雪梅[1] 公衍铎 孙琪[1] 栾晨[1] 唐凯[1] 赵玉洁 Qi Duo;Wang Chengwei;Bai Xuemei;Gong Yanduo;Sun Qi;Luan Chen;Tang Kai;Zhao Yujie(Heilongjiang Meteorological Observatory,Harbin 150030;Daxing’anling Meteorological Office of Heilongjiang Province,Jiagedaqi 165000)

机构地区：[1]黑龙江省气象台,哈尔滨150030 [2]黑龙江省大兴安岭气象局,加格达奇165000

出　　处：《应用气象学报》2024年第3期257-271,共15页Journal of Applied Meteorological Science

基　　金：中国气象局创新发展专项(CXFZ2023011);黑龙江省自然科学基金项目(LH2022D021);黑龙江省科技厅省院合作项目(YS2018Z01);中国气象局2024年复盘总结专项(FPZJ2024-036);黑龙江省气象局“智能网格预报及数值模式释用创新团队”。

摘　　要：利用多源观测资料及ERA5(ECMWF reanalysis version 5)再分析资料,从气候统计、天气分析及物理量诊断等角度,分析2023年8月2—4日黑龙江省东南部一次极端强降水过程。高空持续辐散、副热带高压和东北北部冷涡稳定少动、西南低空急流持续水汽输送等有利条件是此次强降水过程持续时间较长的主要原因。该过程可分为两个阶段:第1阶段,经向水汽净收入层和大气饱和层深厚,大气层结为弱对流不稳定;中层受西北气流控制,低层西南急流发展、伴随弱低涡东移,形成水平风速辐合及系统性上升运动,产生大范围持续性降水;该阶段以层积混合云为主,降水效率高,个别时段伴有列车效应,造成极端小时降水量及较大累积降水量。第2阶段,经向水汽净收入集中在对流层低层,且中心强度较大,对流层低层暖湿、饱和,中高层干冷,大气具有较强对流不稳定;在中层槽和低层暖式切变的系统性抬升以及地形辐合抬升的共同作用下,局地有积云发展,引发短时强降水,降水强度分布不均。From 2 August to 4 August in 2023,a prolonged and extensive extreme heavy rainfall event occurrs in the southeast of Heilongjiang Province.Utilizing multiple observations and ERA5 reanalysis data,characteristics of the precipitation process are analyzed focusing on large-scale circulation background,mesoscale circulation system evolution,environmental conditions from perspectives of climate statistics,weather analysis,and physical quantity diagnosis.Factors contributing to the prolonged extreme heavy rainfall event are explored.Main causes for the long duration of this heavy precipitation event are the stable maintenance of favorable large-scale conditions,such as the persistent divergence of the upper troposphere,the stable location of the west Pacific subtropical high(WPSH)and Northeast China cold vortex(NCCV),and continuous water vapor transport by the southwest jet.Due to the strong southwest jet,there is abundant moisture transfer,primarily through the advection of water vapor,which is the primary source for heavy rainfall.The process can be divided into two stages due to significant differences of rainfall,atmospheric stratification,and local circulation characteristics.In the first stage,the meridional water vapor inflow layer and the saturated layer are thick,resulting in high tropospheric humidity.The atmospheric condition is characterized by weak convective instability.Under the control of the northwest airflow at 500 hPa,the development of southwest jet,along with the influence of a weak eastward-moving vortex system at 850 hPa,results in horizontal wind speed convergence and systematic upward motion,leading to widespread and prolonged precipitation.The heavy rainfall area is mainly composed of cumulus embedded stratus,with a large coverage area of the cloud system,low echo centroid height,and high precipitation efficiency.With weak convective instability that promotes the development of convection and train effect in some periods,extreme hourly precipitation and large cumulative precipitation occur.In

关 键 词：极端强降水 西南急流 列车效应 地形效应 

分 类 号：P458.121.1[天文地球—大气科学及气象学]