一次复杂地形暖区强降水的特征及触发机制分析  

Analysis of the characteristics and trigger mechanism of the warm-sector heavy precipitation over complex terrain

作　　者：周长春[1] 吴蓬萍[2] 周秋雪[1] 

机构地区：[1]四川省气象台,成都610072 [2]中国气象局成都高原气象研究所,成都610072

出　　处：《暴雨灾害》2015年第1期27-33,共7页Torrential Rain and Disasters

基　　金：中国气象局预报员专项项目(CMAYBY2013-059);四川省气象局课题(川气课题2014-开发-02)

摘　　要：利用常规观测资料、地面自动站降水资料、FY-2E云顶亮温资料及NCEP 1°×1°逐6 h再分析资料,对2012年8月16日20时—18日08时副高边缘复杂地形暖区强降水过程的环流背景、环境条件、中尺度特征及其触发机制进行分析。结果表明:暖区强降水发生在四川盆地与青藏高原东坡的过渡带上,呈狭长带状,小时降水中心与MCS云团TBB梯度大值区对应较好。在南海台风西行及副高位置稳定的环流背景下,稳定的副高和近地层热低压阻止了西风带低值系统和地面冷空气影响龙门山地区,使大气高能高湿状态得以维持。同时冷、暖平流在龙门山上空交汇,使得大气层结不稳定性增强。龙门山对台风"启德"东北侧东南气流的强迫抬升最终触发暖区强降水。To investigate the mesoscale characteristics and trigger mechanism of one warm-zone torrential precipitation （WZTP） over complex terrain from 16 to 18 August 2012, conventional observation data, precipitation data of automatic weather stations, TBB data of FY-2E and NCEP 1°×1° reanalysis data are synthesized and analyzed. The results show that the WZTP occurred in the transitional zone between East- ern slope of Tibet Plateau and Sichuan Basin, and was distributed zonally as a belt. Maximum hourly precipitation was located at the area where TBB gradient of MCS was increased. The circulation associated with the WZTP are mainly attributed by the typhoon westward move- ment in the South China Sea and the steady state of Subtropical High. The Subtropical High and warm low-pressure near the surface pre- vented the westerlies trough and cold air from moving across the Longmen Mountain. As a result, the unstable stratification with high energy and temperature over precipitation region can be maintained for a longtime. Furthermore, the convergence of the cold and warm air advec- tions over Longmen Mountain increased the instability of stratification. Finally, the torrential precipitation was triggered by the orography dy- namic lifted by Longmen Mountain.

关 键 词：副热带高压 复杂地形 对流性降水 触发机制 

分 类 号：P458.121[天文地球—大气科学及气象学]