对流涡度矢量垂直分量在西南涡暴雨中的应用  

Application of Vertical Component of Convective Vorticity Vector to the Diagnosis of a Rainstorm Brought by Southwest Vortex

作　　者：陶丽[1] 李国平[1] 

机构地区：[1]成都信息工程学院大气科学学院,成都610225

出　　处：《应用气象学报》2012年第6期702-709,共8页Journal of Applied Meteorological Science

基　　金：国家自然科学基金项目(41175045);公益性行业(气象)科研专项(201106012;201006014)

摘　　要：将对流涡度矢量(CVV)应用于浅薄系统西南低涡引发的暴雨中,特别是将对流涡度矢量垂直分量(C_z)应用在2010年7月16—18日由西南涡引发的一次暴雨过程诊断中。研究了CVV垂直积分的各个分量与6 h累积降水量的关系,尤其是CVV垂直分量在西南涡暴雨过程中的指示意义。诊断结果表明:CVV垂直分量与西南涡引发的暴雨有一定对应关系,强降水发生时段与C_z垂直积分峰值出现的时间对应一致;在对流层低层850 hPa水平分布上,暴雨区位于CVV垂直分量的正值中心附近,偏向其梯度较大处;沿暴雨中心的CVV垂直分量,当对流层低层至高层呈现一致的正值时,暴雨强度会明显加强。Convective vorticity vector （CVV） is employed to analyze the rainstorm caused by the shallow system of southwest vortex during 16--18 July 2010, using convective vorticity vector vertical component （C~）. The relationship between every component of the CVV and the 6-hour accumulated precipitation is investi- gated, particularly the meaning of vertical component in rainstorms caused by southwest vortex. It show~ that the vertical component of CVV is a good indicator of the rainstorm caused by southwest vortex. Th~ occurring time of strong precipitation and the peak value of vertical component of CVV are consistent. If [-C~ reaches an extreme value, the precipitation will change significantly,probably leading to heavy rain phenomenon. Thus the peak time of [-C^3 can be an indicator of the heavy rain forecast. When the rain- storm begins, the precipitation region shows consistently positive values of C~, with the heavy rain to strengthen. When the positive values of C~ expand larger, the contours become intensive, and the gradient increases. The scope of positive values of C~ and the rain belt are largely the same. In the distribution of lower troposphere 850 hPa level, the rainstorm area locates near the center of the positive values of C~ and tend to the larger gradient of C~. The main cause is the positive vorticity advection in front of the westerly trough, so that the vorticity in southern Sichuan and eastern Sichuan enhance, and the wet isentropic sur- face becomes steeply. The rising movement and the water vapor deliver strengthens, which is beneficial to the formation of heavy rain. Along the vertical distribution of C~ in the storm center, the storm intensity increases significantly when vertical components from lower to higher troposphere show consistent positive values. This rainstorm case confirms that the convective vorticity vector can be used for analyzing the shal- low meso-scale system like southwest vortex. However, there are very limited cases, so further validation and improvements are nee

关 键 词：对流涡度矢量 西南涡 暴雨 

分 类 号：P426.62[天文地球—大气科学及气象学]