摘要
采用常规观测资料、NCEP 1°×1°再分析资料及自动站、SWAN、风廓线等资料对2014年8月31日至9月1日渝东北地区出现的一次大暴雨天气进行诊断分析,结果表明：1持续性的强降水产生于有利的环流形势下。华南地区副热带高压稳定维持,副高北侧高空低槽缓慢东移,与低空切变线形成了持续性的大尺度强迫作用,使得强降水长时间维持。2强西南暖湿气流与偏东冷流在渝东北地区交汇,锋生作用显著,暴雨期间锋区呈准静止状态,锋区对流层中低层显著的θse差动平流有利于锋区对流性不稳定增强。3风廓线雷达显示暴雨期间西南低空急流显著增强,1-3km高度低空急流维持超过8h,最大风速超过18m·s^-1,并存在显著的高空辐散、低空辐合。4地形对降水的增幅作用显著。TREC风场显示大巴山南麓维持西南气流,风向与山脉走向近乎垂直,地形的强迫抬升作用加大了山前降水,形成了与山脉走向基本一致的大暴雨区。
A heavy rain event took place in the northeast of Chongqing from August 31 to September 2 in 2014. An analysis is made of this process by using data of conventional observations, NCEP 1°×1°, automatic station, SWAN products, and wind profile. The results show： （1） The persistent heavy rain was produced in a favorable situation. A trough at high altitudes in north of the subtropical high moved slowly due to exceptionally stable subtropical high on the southern China. Persistent large-scale forcing induced by the high-altitude trough and the low-level shear line maintained the consequent heavy rainfall. （2） Strong southwest warm air and northeast cold air besides the low-level shear line intersected in the northeastern region of Chongqing, which led to obvious frontogenesis. The frontal zone was quasi stationary during rainstorms. Different θse in different levels were beneficial to the increasing of instability in the middle and lower troposphere in the front area. （3） Wind profiler radar displayed that the southwest LLJ significantly enhanced during the rainstorms; LLJ sustained more than 8 hours between 1 km and 3 km; and the maximum wind speed exceeded 18 m/s. Significant high divergence and low convergence existed during the rainstorms. （4） The interaction between wind and terrain increased precipitation significantly. TREC （Tracking Radar Echoes by Correlation） winds show that the southwest flow maintained to the south of the Daba Hill, and the wind direction was nearly perpendicular to the mountain strike, so that the terrain effect increased precipitation in front of the mountain, which induced the heavy rainfall along the strike of the Daba Hill.
出处
《气象科技》
北大核心
2016年第2期290-296,共7页
Meteorological Science and Technology
基金
公益性行业(气象)科研专项(GYHY201206028)
重庆市气象局业务技术攻关重点项目(ywgg-201409)共同资助
关键词
暴雨
低空切变线
锋生
低空急流
地形
heavy rain
low-level shear line
frontogenesis
low-level jet
terrain
作者简介
邓承之，男，1983年生，工程师，主要从事短期天气预报工作，Email：95640680@qq．com
