四川盆地突发性暖区暴雨特征及环境场条件分析  

Characteristics and environmental conditions of the sudden warm-sector rainstorms in Sichuan basin

作　　者：肖递祥[1,2,3] 王佳津 曹萍萍[2] 罗辉[2] XIAO Dixiang;WANG Jiajin;CAO Pingping;LUO Hui(Chengdu Institute of Plateau Meteorology,CMA,Chengdu 610072,China;Sichuan Provincial Meteorological Observatory,Chengdu 610072,China;Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province,Chengdu 610072,China)

机构地区：[1]中国气象局成都高原气象研究所,四川成都610072 [2]四川省气象台,四川成都610072 [3]高原与盆地气象灾害四川省重点实验室,四川成都610072

出　　处：《自然灾害学报》2020年第3期110-118,共9页Journal of Natural Disasters

基　　金：中国科学院战略性先导科技专项(A类,XDA23090103);中国气象局气象预报业务关键技术发展专项[YBGJXM(2018)1A];四川省气象局强对流预报创新团队(川气函[2017]313号)。

摘　　要：本文统计了2012~2018年四川盆地在弱天气系统影响条件下出现的30次突发性暖区暴雨过程,按850hPa影响系统将其分为了偏东风型、偏南风型和低涡型3类,并利用地面自动站和实况探空观测资料统计了暴雨的时空分布特征和相关物理量阈值,利用ERA-Interim再分析资料对各类暴雨的环流平均场进行了分析。主要结论为:(1)偏东风型和偏南风型暴雨均出现在盆地西部,其中偏东风型雨带更靠近龙门山脉,低涡型暴雨主要出现在盆地南部,3类暴雨过程中的短时强降水具有明显的日变化特征,都是夜间增多,次日上午减少;(2)暖区暴雨临近时,500hPa四川盆地为西太平洋副热带高压外围的偏南或弱波动气流,700 hPa云贵至四川盆地为西南气流,850 hPa贵州至四川盆地为偏东或偏南气流,平均风速增大2~4m·s-1,暴雨主要出现在850hPa风速辐合及浅薄的低涡环流区域,在偏东风型暴雨过程中,龙门山地形的强迫抬升也起到了重要作用。(3)暖区暴雨发生在异常高能高湿的条件下,850 hPa平均比湿达16.8 g·kg-1、CAPE平均值达1956 J·kg-1、K指数平均值达40.1℃,显著高于气候平均值和一般暴雨过程。The 30 sudden warm-sector rainstorms are analyzed over Sichuan basin during 2012-2018.According to the main trigger systems,they are divided into 3 types:easterly wind,southerly wind,and low vortex.By using the ground automatic stations and the live telecast sounding data,the time-space distribution characteristics and related physical quantities of the warm-sector rainstorms are analyzed,and all kinds of average rainstorm circulation field is analyzed by using ERA-Interim analysis data,the main conclusion is:(1)Both easterly and southerly rainstorms occur in the western part of Sichuan basin.The easterly wind storm belt is closer to the Longmen Mountains,and the low-vortex storm occurs mainly in the southern part of the basin.The short-time heavy precipitation in the process of the three types of rainstorms has obvious diurnal variation characteristics,which increases at night and decreases in the next morning.(2)When warm-sector rainstorm is approaching,Sichuan basin is located on south flow or weak fluctuation at 500hPa,which is the periphery of the western Pacific subtropical high.And there are the southwest flow from Yunnan-Guizhou to Sichuan Basin at 700 hPa,the east or south flow from Guizhou to Sichuan Basin at 850 hPa,easterly or southerly winds will increase to 2~4m·s-1 at 850hPa.The rainstorm mainly appeared in the convergence of wind speed at 850hPa and shallow low-eddy circulation area,among which the easterly type rainstorm also had the forced lifting effect of the landform of Longmen Mountain.(3)The warm-sector rainstorms occur under the condition of abnormal high energy and humidity.The 850hPa average specific humidity is 16.8 g·kg-1,CAPE average value is 1956 J·kg-1,K index average value is 40.1℃.The energy condition in the warm area is significantly higher than the average climatic value and the general rainstorm process.

关 键 词：环境场条件 特征 突发性 暖区暴雨 四川盆地 

分 类 号：P458.1[天文地球—大气科学及气象学] X43[环境科学与工程—灾害防治]