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一次引发极端降水事件的江淮气旋发生发展分析
沈阳1, 孙燕2, 蔡凝昊1, 苏翔1
(1.江苏省气象台;2.江苏省气象学会)
An analysis on the generation and evolution ofa Jiang-huai cyclone with extreme precipitation event
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投稿时间:2017-07-29    修订日期:2018-09-27
中文摘要: 利用NCEP 0.25°× 0.25°再分析数据和多种观测资料,对2017年6月9日-10日在华东地区引发区域性大暴雨并在江苏数个观测站造成极端降水事件的江淮气旋过程进行了分析,从气旋的生成、发展、冷暖峰和相当正压性等方面与前一次降水较弱的江淮气旋过程进行了对比,结论如下:(1)对流层高层正涡度平流及出流区引发高空辐散场,继而导致对流层低层动力减压,是“0609”江淮气旋的启动机制,而“0605”过程中对流层低层强盛的暖平流引起的上升运动导致了气旋的生成;(2)对锋生函数的计算表明“0609”过程中锋生作用较“0605”过程更强,前者暖锋锋区较后者更为陡立且在一定区域内缓慢移动,暖锋附近及暖区一侧上升运动更强且更为深厚,以上因素直接导致了“0609”区域性大暴雨的发生;(3)相对涡度和纬向风0值线的垂直分布表明,“0609”气旋在700hPa以下表现为集中的涡度柱形态,强度较大,系统随高度几近垂直分布,相当正压结构十分明显,而“0605”气旋涡度柱仅存在于850hPa以下,强度较弱,相对涡度和纬向风0值线随高度北倾,斜压性明显;(4)“0609”过程中强降水引起的潜热释放通过涡度混合加强了气旋,加强的气旋又增强了降水,降水和气旋之间建立了类似于“CISK”机制的正反馈过程,这可能是“0609”气旋表现出较强正压性的原因,说明了江淮气旋发展方式的多样性。
Abstract:A Jiang-huai cyclone which caused regional torrential rain in East China and extreme precipitation events at several observatories in Jiangsu province during 9 June,2017 to 10 June was analysed based on NCEP 0.25°× 0.25° reanalysis data and multiple observed data. The generation, development, front structure and equivalent barotropy was researched by compared with another Jiang-huai cyclone with less precipitation. The results are as follows: (1) the divergence caused by positive vorticity advection and distributary at upper troposphere leaded to the generation of "0609" cyclone while the warm advection at lower troposphere triggered the "0605" cyclone; (2) the calculation of frontogenesis function indicated that frontogenesis was much intenser in "0609" cyclone than the other which made the frontal surface less tilted and the upward motion in warm area much stronger and deeper, these factors as well as slow motion of front could be the direct reason for regional torrential rain;(3) vertical profile of relative vorticity and 0 contour of zonal wind indicated that the "0609" cyclone had a intense vorticity column and vertical structure below 700hPa, which made itself some equivalent barotropic, while the "0605" cyclone had a tilted structure and it"s more baroclinic; (4) the latent heat released by intense precipitation could strength the cyclone by mixing vorticity and the cyclone could enhance the precipitation conversely, which made a positive feedback mechanism like CISK between cyclone and its precipitation, this could be the reason for equivalent barotropy of "0609" cyclone which also indicated the multiple evolution pattern of Jiang-huai cyclone.
文章编号:201707290359     中图分类号:    文献标志码:
基金项目:国家自然科学基金资助项目(41575081)和江苏省自然基金资助项目(BK20161603)
引用文本:
沈阳,孙燕,蔡凝昊,苏翔,0.[en_title][J].Meteor Mon,():-.
SHEN Yang,SUN Yan,CAI Ninghao,SU Xiang,0.An analysis on the generation and evolution ofa Jiang-huai cyclone with extreme precipitation event[J].Meteor Mon,():-.