| 一次华北飑线天气过程中环境条件与对流发展机制研究 |
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| 引用本文： | 陈涛,代刊,张芳华.一次华北飑线天气过程中环境条件与对流发展机制研究[J].气象,2013,39(8):945-954. |
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| 作者姓名： | 陈涛 代刊 张芳华 |
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| 作者单位： | 国家气象中心,北京,100081 |
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| 基金项目： | 公益性行业(气象)科研专项（GYHY200906011）和国家气象中心暴雨预报团队项目共同资助 |
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| 摘 要： | 利用多种观测和分析数据对2008年6月23日午后华北地区一次持续时间较长的强飑线天气过程进行了研究。分析表明这是一次在夏季冷涡背景下发生的强对流天气过程,相对孤立的MCSs在副冷锋附近发生发展。此次飑线天气过程中强风暴对流单体、超级单体活跃,对流组织化过程与地面风场辐合线以及锋面有紧密的关系。天气分析表明22日夜间主冷锋过境后,变性高压后部的偏东风以及偏南回流导致在华北东部的锋区开始增强,通过地面观测订正的探空分析表明,对流天气发生前华北地区局地具有较明显的对流潜势。从23日午后开始,河套地区对流层中低层有明显的短波槽扰动发展,在冷涡后部有副冷锋向华北地区逼近,对流的触发与副冷锋密切相关,并通过次级环流方程进一步诊断了锋面所造成的垂直运动;来自气旋后部对流层中高层的强下沉气流,造成了华北地区垂直方向上干湿对比明显,形成较强位势不稳定,有利于对流的触发以及地面大风的形成。通过对垂直风廓线结构和飑线移动速度的分析,表明在此次过程中冷池边界扩张速度与低层风垂直切变大致相当,因此MCS具有较强的强度并维持较长时间。
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| 关 键 词： | 飑线 对流环境条件 锋面 垂直切变 |
| 收稿时间： | 7/5/2012 12:00:00 AM |
| 修稿时间： | 1/6/2013 12:00:00 AM |
Study on Ambient Condition and Initialization Mechanism of Convection in a Severe Squall Line Storm Event in North China |
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| CHEN Tao,DAI Kan and ZHANG Fanghua.Study on Ambient Condition and Initialization Mechanism of Convection in a Severe Squall Line Storm Event in North China[J].Meteorological Monthly,2013,39(8):945-954. |
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| Authors: | CHEN Tao DAI Kan and ZHANG Fanghua |
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| Institution: | National Meteorological Centre, Beijing 100081;National Meteorological Centre, Beijing 100081;National Meteorological Centre, Beijing 100081 |
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| Abstract: | One long lasting squall line storm that struck North China severely in the afternoon of 23 June 2008 is analyzed based on various observation and analysis data collected by radar, satellite, and auto weather stations, etc. This servere convection developed in the background of cold vortex in summer, and an isolated MCS evolved near the sub cold front. Strong convective cells and several super cell storms were active in premature period of the squll line, and the organization of convection is attributed to the surface wind convergence line or front. After the main cold front left at the night of 22 June, the easterly and southerly wind rearside of the high pressure transported warm moist air into the increasing intensity of the frontal zone. On the other hand, from the afternoon of 23 June, a short wave trough near the Hetao Area with high relative humidity developed in the mid and lower levels of troposphere, corresponding to the sub cold front moving towards North China and conecting to the initiation of the convection, and the updraft motion due to the front was diagnosed by the secondary circulation equations. In the rearside of the cyclone, the dry and cold air with obvious subsiding made strong potential instability which is favorable for the convection initiation and formation of strong surface wind. By analyzing the vertical wind profile and the movement of squall line, it is indicated that the boundary moves approximately at the same speed as the lower level vertical shear, so MCS maintains the strength and the lasting time. |
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| Keywords: | squall line convection ambient condition front vertical shear |
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