基于NCEP再分析资料、 常规观测站点降水数据, 研究了2013年5月14 -15日发生的一次西南涡诱生气旋的结构演变特征及其在湖南产生大暴雨的动力学机理, 最后利用Okubo-Weiss参数（OW）及位势涡度（Potential Vorticity, PV）定量分析了西南涡切变线和诱生气旋的发展过程。结果表明: （1）此次大暴雨是一例由西南涡诱生气旋引发的强降水过程。在气旋波生成阶段, 西南涡风场由对称结构变成不对称结构; 在诱生气旋的成熟阶段, 西南涡风场再次发展为对称结构。切变线上的不稳定为气旋性扰动的生成提供了有利环境条件, 导致西南涡诱生气旋波沿切变线东移并随之产生大暴雨。（2）在气旋波生成之前, 西南涡环流及西风绕流涡度带表现为OW参数和PV大值区, 西南涡外围是OW参数负值环绕区, 有利于切变线的生成和维持。在绕流涡度带与切变线结合之后, 切变线的旋转性加强, 风场的旋转性诱生出气旋性扰动。（3）诱生气旋发展的主要原因是气旋波在有利的高低空形势场配置下不断积累正位涡, OW极大值和PV极大值重合并远超停滞的西南涡。
Based on the NCEP reanalysis data and the conventional station precipitation data, the structural evolution features and the dynamic mechanism of the large-scale heavy rainstorm in Hunan Province of the induced cyclone of a Southwest Vortex (SWV) that took place from 14 to 15 May 2013 were studied, and the Okubo-Weiss (OW) parameter and the Potential Vorticity (PV) were used to analyze the development of the shear line and the induced cyclone of SWV.The results show that: （1）The strong precipitation in Hunan Province was a typical heavy rainstorm process triggered by the induced cyclone of SWV.At the generation stage of the cyclone wave, the SWV wind field changed from a symmetrical structure to an asymmetric structure.At the maturity stage of the induced cyclone, the SWV wind field developed into a symmetrical structure again.The instability on the horizontal shear line provided favorable environmental conditions for the generation of cyclonic disturbances, which caused the cyclone wave induced by SWV to move eastward along the horizontal wind shear and produce a heavy rainstorm.（2）Before the cyclone wave was generated, the SWV and the vorticity band of the westerly flow were shown as the OW parameter and the PV large value area, and the periphery of SWV was a surrounding negative-value area of the OW parameter, which was conducive to the generation and stability of the shear line.After the vorticity band was combined with the wind shear, the rotation of shear line is enhanced, and the rotation of the wind field induced cyclonic disturbance.（3）The main reason for the development of the induced vortex was that the cyclone wave accumulated positive vorticity under the favorable high and low altitude situations, and the area of OW maxima and the area of PV maxima overlapped to exceed the stagnant SWV.
[1]Hoskins B, 1997.A potential vorticity view of synoptic development[J].Meteorological Applications, 4(4): 325-334.DOI: 10. 1017/S1350482797000716.
[2]Okubo A, 1970.Horizontal dispersion of floatable particles in the vicinity of velocity singularities such as convergences[J].Deep Sea Research and Oceanographic Abstracts, 17(3): 445-454.DOI: 10.1016/0011-7471(70)90059-8.
[3]Wang W, Kuo Y H, Warner T T, 1993.A diabatically driven mesoscale vortex in the lee of the Tibetan Plateau[J].Monthly Weather Review, 121(9): 2542-2561.DOI: 10.1175/1520-0493(1993)121<2542: addmvi>2.0.co; 2.
[4]Weiss J, 1991.The dynamics of enstrophy transfer in two-dimensional hydrodynamics[J].Physica D-nonlinear Phenomena, 48(2/3): 273-294.DOI: 10.1016/0167-2789(91)90088-Q.
[5]Zhong R, Zhong L, Hua L, al et, 2014.A climatology of the Southwest Vortex during 1979-2008[J].Atmospheric and Oceanic Science Letters, 7(6): 577-583.DOI: 10.3878/AOSL20140042.
[6]陈启智, 黄奕武, 王其伟, 等, 2007.1990 -2004年西南低涡活动的统计研究[J].南京大学学报（自然科学版）, 43(6): 633-642.DOI: 10.3321/j.issn: 0469-5097.2007.06.008.
[7]陈忠明, 闵文彬, 2000.西南低涡的统计研究[C]//陶诗言, 陈联寿, 徐祥德, 等编著.第二次青藏高原大气科学实验理论研究进展.北京: 气象出版社, 368-378.
[8]陈贵川, 谌芸, 王晓芳, 等, 2018.一次冷性停滞型西南低涡结构的演变特征[J].高原气象, 37(6): 1628-1642.DOI: 10.7522/j.issn.1000-0534.2018.00093.
[9]傅慎明, 赵思雄, 孙建华, 等, 2010.一类低涡切变型华南前汛期致洪暴雨的分析研究[J].大气科学, 34(2): 235-252.DOI: 10. 3878/j.issn.1006-9895.2010.02.01.
[10]傅慎明, 2009.引发强降水的西南低涡结构特征及其发生发展机理研究[D].北京: 中国科学院大气物理研究所, 1-211.
[11]高文良, 郁淑华, 2018.高原涡诱发西南涡伴行个例的环境场与成因分析[J].高原气象, 37(1): 54-67.DOI: 10.7522/j.issn. 1000-0534.2017.00020.
[12]高笃鸣, 李跃清, 程晓龙, 2018.基于西南涡加密探空资料同化的一次奇异路径耦合低涡大暴雨数值模拟研究[J].气象学报, 76(3): 343-360.DOI: 10.11676/qxxb2018.008.
[13]何光碧, 2012.西南低涡研究综述[J].气象, 38(2): 155-163.DOI: 10.7519/j.issn.1000-0526.2012.2.003.
[14]李超, 李跃清, 蒋兴文, 2017.夏季长生命史盆地涡活动对川渝季节降水的影响[J].高原气象, 36(3): 685-696.DOI: 10.7522/j.issn.1000-0534.2016.00064.
[15]李国平, 陈佳, 2018.西南涡及其暴雨研究新进展[J].暴雨灾害, 37(4): 293-302.DOI: 10.3969/j.issn.1004-9045.2018.04.001.
[16]李山山, 李国平, 2017.一次高原低涡与高原切变线演变过程与机理分析[J].大气科学, 41(4): 713-726.DOI: 10.3878/j.issn. 1006-9895.1611.16179.
[17]李跃清, 徐祥德, 赵兴炳, 2012.西南涡大气科学试验的观测布局理论与实践[J].中国工程科学, 14(9): 35-45.DOI: 10.3969/j.issn.1009-1742.2012.09.005.
[18]廖移山, 冯新, 石燕, 等, 2011.2008年“7.22”襄樊特大暴雨的天气学机理分析及地形的影响[J].气象学报, 69(6): 945-955.DOI: 10.11676/qxxb2011.082.
[19]马勋丹, 智协飞, 王静, 等, 2018.1979-2016年夏季西南涡活动及其与降水的关系[J].大气科学学报, 41(2): 198-206.DOI: 10.13878/j.cnki.dqkxxb.20171015001.
[20]寿绍文, 2010.位涡理论及其应用[J].气象, 36(3): 9-18.DOI: 10.7519/j.issn.1000-0526.2010.3.002.
[21]王其伟, 谈哲敏, 2006.地形对西南低涡涡源形成的动力影响作用[EB/OL].北京: 中国科技论文在线[2006-11-20].http: //.
[22]王晓芳, 廖移山, 闵爱荣, 等, 2007.影响“05.06.25”长江流域暴雨的西南低涡特征[J].高原气象, 26(1): 187-196.
[23]王毅, 何立富, 代刊, 等, 2017.集合敏感性方法在高原涡和西南涡引发暴雨过程中的应用[J].高原气象, 36(5): 1245-1256.DOI: 10.7522/j.issn.1000-0534.2016.00102.
[24]朱禾, 邓北胜, 吴洪, 2002.湿位涡守恒条件下西南涡的发展[J].气象学报, 60(3): 343-351.DOI: 10.3321/j.issn: 0577-6619. 2002.03.010.
