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气象:2010,36(4):7-15
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移出与未移出高原的两类低涡环流特征的对比分析
(1.四川省气象台, 成都 610072 ;2.成都市气象台, 成都 610072)
Comparison Analysis of the Circulation Characteristics of Plateau Vortex Moving out of and not out of the Plateau
(1.Sichuan Provincial Meteorological Observatory, Chengdu 610072;2.Chengdu Meteorological Observatory, Chengdu 610072)
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投稿时间:2009-05-20    修订日期:2009-11-19
中文摘要: 利用NECP再分析资料,采用对比分析方法,对2000—2004年汛期(6—9月)的高原低涡活动过程进行普查,并对移出高原低涡与未移出高原低涡在其生成时刻的环流特征场,以及移出高原低涡的移出高原时刻与未移出高原低涡的强盛时刻的环流特征场进行对比分析。分析表明: 500 hPa上,移出高原低涡背景环流中巴尔喀什湖低槽、东亚大槽比未移出高原低涡深,蒙古高压脊更强,背景环流经向度大,而且副热带高压比未移出高原低涡西伸明显;暖平流对高原低涡的生成很重要,而涡后新疆冷平流有利于高原低涡移出高原主体;青藏高原上的正涡度平流有利于高原低涡的生成和加深,河套地区正涡度平流带的存在有利于高原低涡的移出。在200 hPa上,南亚高压的存在有利于高原低涡的生成,移出高原低涡上空的南亚高压强度要强于未移出高原低涡;青藏高原东北部、四川盆地到陕西一带位于高空急流入口区南侧时有利于高原低涡东移。找出高原低涡移出与未移出高原主体的环流场、温度平流场、涡度平流场的异同特征,为高原低涡能否东移出高原主体提供科学依据。
Abstract:Using the NCEP reanalysis data, based on the comparison analysis, the general circulation and impacting systems of plateau vortex moving out of the plateau or not in summer from 2000 to 2004 are analyzed. The research indicates that at 500 hPa level, the circulation background of the plateau vortex moving out of the plateau abbreviated as PV (out), including the trough in the Balkhash Lake, East Asian major trough and high pressure ridge at Mongolia is stronger compared to the circulation background of plateau vortex moving not out of the plateau abbreviated as PV (not out), that is, the circulation background of PV (out) has the meridional circulation increased. And the Pacific subtropical high westward extension is significant in the circulation background of PV (out) compared with PV (not out). In the middle troposphere the warm advection is very important to the generation of the plateau vortex and vortex is apt to move eastward when there is a cold advection in Xinjiang. On the Tibeten Plateau, the positive vorticity advection in the middle troposphere is very important to the generation of the plateau vortex. The positive vorticity advection of PV (out) is weaker compared with it of PV (not out), and the vortex is apt to move eastward when there is a positive vorticity advection in Ordos Region. In the upper troposphere, the existence of South Asia high is beneficial to the generation of plateau vortex, and over PV (out), the strength of South Asia high is stronger than it of PV (not out).And when northeastern part of the Tibetan Plateau, the Sichuan Basin, Shanxi Province are located in the south side of the entrance of the upper jet stream, it is beneficial to plateau vortex to move eastward. Analysis of the similarities and differences between PV (out) and PV (not out) in the general circulation,the temperature advection and the vorticity advection could put forward the scientific basis to the prediction of PV(out) and PV (not out).
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基金项目:国家自然科学基金项目“青藏高原低涡切变线形成维持机制研究”(40775032)、“青藏高原东北部强降水天气过程的演变特征及其机理研究”(40675059)和四川省气象局重点课题“西太平洋副热带高压对四川暴雨的影响研究”(2009-02)资助
引用文本:
顾清源,师锐,徐会明,2010.移出与未移出高原的两类低涡环流特征的对比分析[J].气象,36(4):7-15.
GU Qingyuan,SHI Rui,XU Huiming,2010.Comparison Analysis of the Circulation Characteristics of Plateau Vortex Moving out of and not out of the Plateau[J].Meteor Mon,36(4):7-15.