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气象:2007,33(1):99-106
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青藏高原东侧突发性暴雨的湿位涡诊断分析
(1.陕西榆林市气象局 719000;2.陕西省气象台;3.河北沧州市气象台)
Diagnostic Analysis of Moist Potential Vorticity for Abrupt Rainstorm in Eastern Qinghai Tibetan Plateau
(1.Yulin Meteorological Office, Shaanxi Province 719000;2.Shaanxi Meteorological Bureau;3.Cangzhou Meteorological Office, Hebei Province)
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投稿时间:2006-06-12    修订日期:2006-10-23
中文摘要: 利用MICAPS系统提供的常规观测资料对2004年6月29日、2004年8月10日发生在关中和 陕北的突发性大暴雨进行湿位涡诊断分析。分析表明,700 hPa等压面上,MPV1≤-0.3PVU 中尺度对流不稳定区的生成、伴随对流不稳定区临近上游MPV1≥0.3PVU中尺度对流 稳定区的生成,是形成突发性暴雨的湿正压场特征。伴随高原槽东移入河套(或关中),槽 后有MPV2<0湿斜压中心生成,槽前有MPV2>0湿斜压中心生成,正负湿斜压中 心在暴雨区及其临近上游生成MPV2等值线密集区,形成了突发性暴雨的700hPa湿斜压 场特征。暴雨区上空有深厚湿位涡负值层的形成,伴随暴雨区上游对流层中低层有正 湿位涡柱东移在暴雨区形成陡直的湿位涡等值线密集区,对突发性暴雨的发生有指示意义。 扰动湿位涡的三维空间结构及其演变也是青藏高原东侧突发性暴雨预报当中可利用的重要 信息。
Abstract:Using the observational data provided by MICAPS, the characteristics of the moist potential vorticity of two abrupt torrential rain events in Guanzho ng, Shaanxi on June 29, 2004, and in northern Shaanxi on August 10, 2004 are ana lyzed. The results show that at 700 hPa level, the generation of a mesoscale c onvective instable area with MPV1≤-0.3 PVU and a mesoscale convective stab le area with MP1≥0.3 PVU at the upper stream, is favorable for moist barotropi c features, and contributes to the occurrence of abrupt torrential rains. The favorabl e moist baroclinic features develop at 700hPa level, while the plateau trough mo ves eastwardsto Hetao area or Guanzhong area. A moist baroclinic center with MPV 2<0 generates at the rear of the trough, as a moist baroclinic center with t he MP2>0 is in front of the trough. The positive and negative moist barocl inic centers above rainfall location and its neighboring upper stream, form an isoline concentrated zone of MPV2, which coupled with the mesoscale convective i nstable center with MPV1≤-0.3 PVU accords to the rainfall location. On MPV 1 zonal cross section chart, an MPV column, nearly through upper and low levels, builds up in west tilting with height at neighboring upper stream of the rainfall location before the Guanzhong torrential rain. While at Ansai, a funnel like positive  MPV extends from upper level down to the lower troposphere, which overlaps the nega tive MPV area developing in the boundary layer. The deep negative MPV la yer develops above the rainfall location. Simultaneously, at the mid low level of tropo sphere, the positive MPV column moves eastwards to the rainfall location to f orm a steep isoline concentrated zone of MPV, which holds indicative meaning to theoccurrence of abrupt torrential rains. The MPV disturbance owns the characte ristic of spreading from high to low latitudes. Its three dimensional structure and evolution are the useful information in predicting abrupt torrential rain occurr ing in the eastern Tibetan Plateau.
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井喜,李明娟,王淑云,胡春娟,2007.青藏高原东侧突发性暴雨的湿位涡诊断分析[J].气象,33(1):99-106.
Jing Xi,Li Mingjuan,Wang Shuyun,Hu Chunjuan,2007.Diagnostic Analysis of Moist Potential Vorticity for Abrupt Rainstorm in Eastern Qinghai Tibetan Plateau[J].Meteor Mon,33(1):99-106.