高原低涡移出高原的动力结构特征分析  

Analysis on the Dynamic Structure of Vortex Moving out of the Tibetan Plateau

作　　者：柳草[1,2] 李跃清[2] 李德俊 

机构地区：[1]中国气象科学研究院,北京100081 [2]中国气象局成都高原气象研究所,成都610072 [3]湖北省恩施州气象局,恩施州445000

出　　处：《高原山地气象研究》2009年第3期8-11,共4页Plateau and Mountain Meteorology Research

基　　金：江苏省气象灾害重点基金项目(KLME050210);国家重点基础研究发展计划(2003CB415201-6);中国气象局气候变化专项(CCSF2007-23)

摘　　要：利用ECMWF资料对2001年6月1～5日东移出高原的低涡个例的动力结构进行了诊断分析。结果表明：（1）低涡东移过程中，闭合等高线或者闭合气旋式环流的垂直厚度随时间呈加厚趋势；（2）高原低涡在东移过程中，垂直方向上几乎都是正涡度，500hPa上正涡度随时间呈增强趋势；（3）在高原上时涡区明显低层辐合、高层辐散；移出高原后表现为微弱的低层辐合、高层辐散，甚至低层辐散、中层辐合、高层辐散。（4）处于高原上时涡区整层都为上升运动，移出高原以后上升运动微弱，中低空经常为下沉运动。（5）低涡处于高原上时，涡区在边界层始终有水汽辐合，移出高原以后在低空只有微弱的水汽辐合甚至辐散。涡区外围东南侧的槽前脊后区存在低空急流，是水汽通量和水汽辐合的大值区。Using the ECMWF data,we researched the dynamic structure of the vortex case ＂01.6.1 -5＂ moving out of the Tibetan Plateau. Conclusions are obtained as follows： i）In the process of moving eastwardly, the thickness of closed contour or closed cyclonic circumfluence of vortex shows increasing trend with time ; ii） In the process of moving eastwardly, in the vertical direction,the ＂01.6. 1 -5＂ shows almost positive vorticity. At 500hpa, positive vorticity displays increasing trend with time. iii） When it is on the plateau, lower - level convergence and upper - level divergence are clearly in the vortex. When it move out of the plateau, lower - level convergence and upper - level divergence are weak in the vortex, iv） When it is on the plateau, in the vortex, the total atmosphere rise. When it move out of the plateau, rising slows down, even sinking usually at middle -low level, v）When it is on the plateau, near the boundary there is always water vapor convergence in the vortex. When it moves out of the plateau, at the lower - level water vapor convergence turns weak, even turns to divergence. While at the area before trough and after ridge, there is lowerlevel jet, so both water vapor flux and convergence are obvious .

关 键 词：高原低涡 移出 动力结构 

分 类 号：P434[天文地球—大气科学及气象学]