地面热源强迫对青藏高原低涡作用的动力学分析
A DYNAMICAL STUDY OF THE ROLE OF SURFACE HEATING ON THE TIBETAN PLATEAU VORTICES
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摘要: 将一类暖性青藏高原低涡考虑为受加热和摩擦强迫作用并满足热成风平衡的轴对称涡旋系统,给定符合高原地面加热特点的加热分布函数,通过求解简化后的柱坐标系中的涡旋模式,得到了低涡对应的流函数、水平流场、水平散度场和垂直运动场的解析解,分析了地面热源对高原低涡流场结构的作用,给出了高原低涡眼壁内、外侧以及不同高度上的水平流场、水平散度场和垂直流场的结构特征,对影响低涡生成的主要因子进行了讨论。研究结果揭示了地面热源强迫对高原低涡的形成及结构特征的重要作用。Abstract: The plateau vortex in this study is a type of vortex generated over the main part of the Tibetan Plateau. It is mainly on 500 hPa isobaric surface with its horizontal scale from 400 to 500 km and life circle from one to three days. The temperature structure of most plateau vortexes is warm. The Tibetan Plateau vortex is advantageous to severe weather processes. They usually induce storm rainfall or thunderstorm on large scale in the upper reaches of the Yangtze River (especially in Sichuan Basin) and even in the downstream of the plateau, when they develop and move eastward out of the plateau. In this paper, the vortices over the Tibetan Plateau are assumed to be axisymmetrical and thermal-wind balanced systems forced by specific surface heating and friction, and solved as an initial-value problem of linearized vortex equation set in cylindrical coordinates. The role of surface heating on the structure of plateau vortices is analyzed in detail and horizontal and vertical flow field and divergence of the vortex are drawn. The results show that surface heating play an important role in the genesis of plateau vortex and its structure.
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Key words:
- vortex /
- Tibetan plateau /
- surface heating source /
- heating function /
- flow field /
- structure
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[1] 杨克明,毕宝贵,李月安,等.1998年长江上游致洪暴雨的分析研究[J].气象,2001,27(8):9-14. [2] KEVIN W,WATTERSON I G.Tropical cyclone-like vortices (TCLV) in a limited area model-comparison with observed climatology[J].J Climate,1997,10 (9):2240-2259. [3] 叶笃正,高由禧.青藏高原气象学[M].北京:科学出版社,1979:122-126. [4] 简茂球,罗会邦,乔云亭.青藏高原东部和西太平洋暖池区大气热源与中国夏季降水的关系[J].热带气象学报,2004,20(4):355-364. [5] 单寅,林珲,付慰慈,等.夏季青藏高原上中尺度对流系统初生阶段特征[J].热带气象学报,2003,19(1):61-66. [6] 乔全明,张雅高.青藏高原天气学[M].北京:气象出版社,1994:120-155. [7] 周明煜,徐祥德,卞林根,等.青藏高原大气边界层观测分析与动力学研究[M].北京:气象出版社,2000:57-78. [8] 盛华,陶诗言.青藏高原和落基山对气旋的动力影响[J].气象学报,1988,46(2):130-141. [9] 罗四维.青藏高原及其邻近地区几类天气系统的研究[M].北京:气象出版社,1992:7-55. [10] 陈伯民,钱正安,张立盛.夏季青藏高原低涡形成和发展的数值模拟[J].大气科学,1996,20(4):491-502. [11] 郁淑华,何光壁.对流层中上部水汽对高原低涡形成影响的数值试验[J].南京气象学院学报,2001,24(4):553-559. [12] 高守亭.行星边界层内低涡的环流结构[J].气象学报,1983,41(3):285-295. [13] 高守亭.流场配置及地形对西南低涡形成的动力作用[J].大气科学,1987,11(3):263-271. [14] 李国平,蒋静.一类奇异孤波解及其在高原低涡结构分析中的应用[J].气象学报,2000,58(4):447-456. [15] 李国平.青藏高原动力气象学[M].北京:气象出版社,2002:135-193. [16] GRAY S L,CRAIG G C.A simple theoretical model for the intensification of tropical cyclones and polar lows[J].Quart J Roy Meteorol Soc,1998,124:919-947.
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