贵州2次MCC暴雨诊断和触发机制对比分析  

Comparison diagnosis and discussion of trigger mechanism of two MCC heavy rain systems in Guizhou

作　　者：熊伟 罗喜平 周明飞 

机构地区：[1]贵州省气象台,贵州贵阳550002

出　　处：《云南大学学报（自然科学版）》2014年第1期66-78,共13页Journal of Yunnan University(Natural Sciences Edition)

基　　金：国家自然科学基金(41065003);公益性行业(气象)科研专项(GYHY201306059)

摘　　要：用FY2-D卫星红外云图云顶亮温(TBB)、常规观测资料和NCEP1°×1°格点再分析资料对2008年5月29—30日("0529")与2010年6月16—17日("0616")贵州2次MCC暴雨天气过程进行诊断分析和触发机制讨论.结果显示:2次MCC发展的历程不同,"0529"MCC最初由多个较小的对流系统合并发展形成中β尺度对流系统,"0616"MCC却由单个对流系统迅速发展形成.2次MCC过程大气低层的影响天气系统明显不同,"0529"MCC天气过程中冷空气占据主导地位,"0616"MCC天气过程中,西南低空急流起到了关键性的作用.诊断分析发现:"0529"MCC,大气低层的动力条件和水汽辐合剧烈,因此对流和短时强降水更强."0616"MCC,动力条件和水汽辐合垂直方向伸展的高度高,水汽的输送持续,形成了较广范围的暴雨天气.利用锋生函数针对2次MCC过程触发机制的讨论显示:"0529"MCC,受冷锋影响,加大了经向风的东西向切变,Af伸长变形明显;同时形成θse密集区,有利的热力锋生条件,使得锋生加强."0616"MCC,低空急流的建立和加强,形成有利的动力锋生条件,使得伸长变形A f和切变变形B f均对锋生作出明显贡献.Two MCC heavy rain processes in 29th -30th May 2008 （＂0529＂） and 16th -17th June 2010 （＂0616＂） in Guizhou Province have been analyzed on the base of the TBB of FY2 -D meteorological satellite, conventionally observational data and the NCEP 1° × 1° reanalysis data. The results showed that the development processes of two MCC heavy rainfalls were different. In the＂0529＂ MCC case, several meso -fl -scale convective cells grew up and combined to generate MCC. In the＂0616＂ MCC case,the single convective cell grew up quick- ly, finally converted to the MCC. The two cases had different effects on the synoptic system at low level. Cold air took hold in ＂0529＂ MCC case, while southwester low - level jet took hold in ＂0616＂ MCC case. After diagnostic analysising, we also found that the convergence of dynamic conditions and moisture was acute, so convection cur- rent and short - term heavy rainfall were strong in ＂0529＂ MCC case. While the convergence of dynamic condi- tions and moisture extended high at vertical, water -vapor persistently transferred long, which formatted the stormy weather for long time. The frontogenesis function of the two MCC case has been analyzed. It showed that in ＂0529＂ MCC case, elongation deformation Af had obvious effect on frontogenesis. In ＂0616＂ MCC case, elonga- tion deformation Af and shear deformation Bf were both crucial to the formation of frontogenesis.

关 键 词：中尺度对流复合体(MCC) 暴雨 锋生函数 

分 类 号：P426.62[天文地球—大气科学及气象学]