贵州望谟初夏暴雨环境场和物理量场合成分析  

Synthetic Analyses on Environmental and Physical Field of Rainstorm in Early Summer in Wangmo,Guizhou

作　　者：杜小玲[1,2] 杨静 彭芳 许可 

机构地区：[1]贵州省气象台,贵州贵阳550002 [2]贵州省山地气候与资源重点实验室,贵州贵阳550002

出　　处：《高原气象》2013年第5期1400-1413,共14页Plateau Meteorology

基　　金：国家自然科学基金项目(40965004;40930951);贵州省科技厅黔科合J字(20102059)

摘　　要：利用NCEP/NCAR 1°×1°格点再分析资料、FY-2C相当黑体亮温TBB和温度、降水两要素逐时降水资料,选取5次形态相近的望谟夏初暴雨过程,对暴雨发生前、暴雨初期、强盛期及减弱期多个时次的环境场和物理量场进行了合成分析。结果表明,望谟夏初暴雨的主要影响系统是高原短波槽、低层切变线、低空急流和地面弱冷空气,其相互作用诱发了地面辐合线的锋生,导致暴雨发生;暴雨主要集中在23:00-03:00(北京时)之间;中尺度对流复合体MCC或准MCC的形成和发展对望谟暴雨有直接影响;暴雨发生前关键区处于高湿不稳定层结和正涡度辐合中。暴雨强盛时刻,低层辐合、高层辐散的结构特征最为显著;锋生造成的强降水出现在锋区南侧和暖湿空气北侧的强上升运动区;锋生函数揭示出对流层低层锋生出现在800hPa附近;正压非平衡强迫负值区位于贵州西南部,负值中心最强时刻出现在强降水峰值发生前10h左右,这可能是望谟强降水启动的一种机制。合成分析揭示了望谟产生暴雨的共性,为今后预报此类暴雨提供了思路。但这类方法同时可能会平滑部分个性特征,在分析或预报某一次过程时,系统强弱和物理量上可能存在一定差异。Using 1°×1° reanalysis data from the NCEP/NCAR, TBB data of FY-2C, and the hourly precip- itation data for these two elements, the environmental and physical field at stage prior to the occurrence of torrential rain storm, developing, mature, and dissipation stages were synthetic analyzed to selecte five similar rainstorm processes in early summer in Wangmo. The results show that the main influence systems are plateau short wave trough, low-level shear line, low-level jet stream and weak surface cold air. The in- teractions of these systems induce the frontogenesis of surface convergence line to finally result in the tor- rential rainstorm. The rainstorm in Wangmo mainly occurs from 23：00 to 03：00 （Beijing time）. The for- mation and evolution of MCC or quasi-MCC have direct influence on the rainstorm in Wangmo. The key area is located in high moisture unstable stratification and the positive vorticity convergence zone before the torrential rainstorm occurring. At the mature stage of torrential rainstorm, the structural characteristics of low level convergence and high level divergence are prominent. The heavy precipitation caused by fronto- genesis occurs in the south of front and north of warm-moist air. The frontogenesis function reveals that frontogenesis in low level troposphere occur near 800 hPa. Negative non-equilibrium forced area is located in southwest Guizhou. The strongest moment of the negative center is about 10 h before the peak of heavy precipitation, it might be a start mechanism of heavy precipitation. The synthetic analysis reveals the com- monality of the formation of torrential rainstorm in Wangmo, provides a way for forecasting this type of torrential rainstorm in the future. However, this method may be also some smooth characteristics, to ana- lyze or forecast a process, the strength of systems and physical quantities might be different.

关 键 词：暴雨 合成分析 锋生 正压非平衡强迫 

分 类 号：P458.121.1[天文地球—大气科学及气象学]