台风与冷空气对重庆“9.17”大暴雨的影响分析  

Analysis of the “9.17” heavy rainfall in Chongqing under the influence of the typhoon and cold air

作　　者：陈鹏 庞玥 张虹 刘毅 何军 

机构地区：[1]重庆市气象台,重庆401147

出　　处：《暴雨灾害》2017年第3期227-234,共8页Torrential Rain and Disasters

基　　金：中国气象局预报员专项(CMAYBY2016-060)

摘　　要：利用实况降水资料、雷达资料以及NCEP 1°×1°逐6 h再分析资料,对2014年9月17—19日发生在重庆的大暴雨过程进行分析研究。结果表明:(1)大暴雨的环流背景场在中高纬为"两槽一脊"的形势,高原上高空槽东移至四川盆地中东部,并引导槽后冷空气扩散南下影响西南地区。(2)台风"海鸥"减弱并演变成切变线,热带低压环流"凤凰"加强发展并向北移动,从而对副热带高压形成"挤压",使得副热带高压主体稳定少动且经向度逐渐加大,并与"海鸥"相互作用,将南海与孟加拉湾的暖湿气流及不稳定能量输送至降水区。(3)降水初期,降水区上空整层都为暖平流控制,此后随着槽后冷空气的侵入,降水区对流层低层出现弱的冷平流,且强度逐渐增强。(4)偏北冷空气由低层侵入与偏南暖湿气流交汇,引起锋生,形成一条向西北倾斜的能量锋区,同时随着冷空气向南逐渐扩散,暖湿空气沿能量锋区向上爬升,触发强烈的垂直上升运动,降水增强。Based on observed precipitation data, radar data and NCEP 6 h interval reanalysis data with 1°×1° resolution, we analyze the heavy rainfall event in Chongqing from September 17 th to September 19 th, 2014. The results are as follows.(1) The circulation background of that heavy rainfall maintains the'two troughs and one ridge'situation in mid-latitudes. The plateau trough moves eastward to the middle and eastern part of the Sichuan Basin to cause cold air behind the trough flowing southward and affecting Southwestern China. The tropical cyclone'Seagull'transports warm air and instability from South China Sea to the heavy rainfall region, together with water vapor from the bay of Bengal.(2) Typhoon 'Seagull' weakened and evolved into a shear line. The tropical depression 'Phoenix' strengthens and presses subtropical anticyclone, which makes subtropical anticyclone stable in motion and meridional circulation increases. The typhoon 'Seagull' interact with typhoon 'Phoenix' that transport the warm and humid air and unstable energy of South China Sea and the bay of Bengal to the precipitation area together.(3) The entire layer of the precipitation area is controlled by warm advection at the beginning of the heavy rainfall, while weak cold flow appears and gradually intensifies in the lower troposphere as the cold air behind the trough pours into the area.(4) The cold air from the north pouring into the lower layer converges with the warm and wet air from the South, resulting in an energy front tilting northwest,and the warm and wet air climbs along the energy front with the cold air spreading south, leading to enhanced ascending motion in the precipitation area to increase rainfall.

关 键 词：暴雨 水汽通量散度 台风 能量锋区 冷空气 

分 类 号：P458.121.1[天文地球—大气科学及气象学]