| 东北一次雪飑事件的触发机制研究 |
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| 作者单位： | Key Laboratory of Meteorological Disaster,Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing,China;Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing,China;Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing,China;Key Laboratory of Meteorological Disaster,Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai,China;Jilin Weather Modification Office,Changchun,China |
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| 基金项目： | the National Key Research and Development Pro-gram，grant numbers 2018YFC1507104 and 2019YFC1510400;This study was supported by the Strategic Priority Research Pro-gram of the Chinese Academy of Sciences，grant numbers XDA17010105 and XDA20100304;and the National Natural Sci-ence Foundation of China，grant numbers 41775140 and 41790471;the Key Projects of Jilin Province Science and Technology Development Plan，grant numbers 20180201035SF |
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| 摘 要： | 2017年1月26日,中国东北地区发生了一次短时强降雪过程.本文利用ECMWF再分析数据诊断该过程的可能触发机制.分析表明,该过程可分两个阶段:初生阶段降雪远离高地形,低层锋生和有利的辐散场配置激发上升运动释放不稳定;增强阶段雪带接近长白山,低层锋生,地形环流以及与低空急流有关的风切变共同释放锋前不稳定.本文进一步计算了包含广义位温的修正Q矢量方程.结果表明,锋生项对沿湿等熵线的负Q矢量散度贡献较大,而拟涡度项在暖区强风切变区域中比较显著,两项在激发上升运动中同等重要.
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| 关 键 词： | 雪飑 锋生 Q矢量 |
Trigger mechanism of a snow burst event in Northeast China |
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| Authors: | Baofeng Jiao Lingkun Ran Xinyong Shen Yanbin Qi |
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| Abstract: | A snow burst event characterized by brief heavy snowfall affected Northeast China and caused serious social im-pact on 26 January 2017,with the snowband generally aligned with a northeast-southwest-oriented cold front.ECMWF reanalysis data were used to diagnose the possible trigger mechanism.Results showed there were two stages:(a)an initial stage far away from the Changbai Mountains,and(b)an enhancement stage under the influ-ence of high terrain.During the initial stage,the coupling of low-level frontogenesis and a favorable convergence pattern caused strong upward motion,contributing to the release of instability.When the snowband approached the high terrain during the enhancement stage,the various instabilities were triggered by the low-level frontoge-nesis,terrain circulation,and strong wind shear associated with the low-level jet.Further,a modified Q-vector divergence including generalized potential temperature was calculated to diagnose the vertical motion.It showed that the frontogenesis terms contributed greatly to the negative Q-vector divergence along the moist isentropes,while the pseudo-vorticity terms played a role in the regions with strong wind shear associated with the low-level jet in the warm section,suggesting both were important in stimulating the ascending motion.The regions with negative Q-vector divergence had a close relationship with the vertical structure of convection,indicating the potential to track the development of the snowband in the next few hours. |
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| Keywords: | Snow burst Frontogenesis Q-vector |
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