| 2011～2012年冬季欧亚大陆低温严寒事件与平流层北极涛动异常下传的影响 |
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| 引用本文： | 兰晓青,陈文.2011～2012年冬季欧亚大陆低温严寒事件与平流层北极涛动异常下传的影响[J].大气科学,2013,37(4):863-872. |
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| 作者姓名： | 兰晓青 陈文 |
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| 作者单位： | 1.中国科学院大气物理研究所季风系统研究中心,北京100190;中国科学院研究生院,北京100049 |
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| 基金项目： | 国家重点基础研究发展规划项目2010CB428603,国家自然科学基金资助项目 41025017 |
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| 摘 要： | 利用NCEP-NCAR 再分析资料分析了2011～2012 年冬季发生在欧亚大陆的一次异常低温严寒事件的大气环流演变过程以及可能的成因。这次低温事件,主要出现在2012 年1 月下旬至2 月上旬,持续大约3 周左右,非常强的低温异常覆盖了几乎整个欧洲以及东亚的西伯利亚、蒙古国和我国东北、华北等地。这次低温事件的演变与对流层北极涛动(AO)由正位相转变为负位相的时间相匹配,意味着AO 可能发挥重要作用。进一步分析表明,前期行星波的异常上传导致平流层发生爆发性增温现象,极夜急流减弱,AO 位相首先在平流层由正变负;在2～3 周左右的时间内,平流层AO 异常信号逐渐下传,使得对流层AO 也转为负位相;随后,乌拉尔山阻塞高压异常发展,极区的冷空气不断向南爆发,先后在东亚和欧洲造成剧烈的降温,导致低温严寒事件。因此,考虑平流层环流的异常可能有助于提高欧亚大陆冬季低温严寒事件的预测能力。
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| 关 键 词： | 冬季低温严寒事件 北极涛动 平流层环流 行星波 |
| 收稿时间： | 2012/4/14 0:00:00 |
| 修稿时间： | 9/7/2012 12:00:00 AM |
Strong Cold Weather Event over Eurasia during the Winter of 2011/2012 and a Downward Arctic Oscillation Signal from the Stratosphere |
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| LAN Xiaoqing and CHEN Wen.Strong Cold Weather Event over Eurasia during the Winter of 2011/2012 and a Downward Arctic Oscillation Signal from the Stratosphere[J].Chinese Journal of Atmospheric Sciences,2013,37(4):863-872. |
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| Authors: | LAN Xiaoqing and CHEN Wen |
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| Institution: | 1.Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100190;Graduate University of Chinese Academy of Sciences, Beijing 1000492.Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100190 |
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| Abstract: | The circulation evolution and possible causes of a severe cold event over the Eurasian continent during the winter of 2011/2012 were investigated with the NCEP-NCAR reanalysis data. Strong cold anomalies covering most of Europe, Mongolia, and northeastern China began in late January 2012 and lasted for about 3 weeks. Analysis results indicate that this cold event coincided with the phase of the Arctic Oscillation (AO) changing from positive to negative, which implied a possible impact of the AO. Before this AO phase change, a minor warming occurred in the stratosphere caused by an anomalous upward propagation of planetary waves. The polar night jet then decelerated and the AO changed its sign in the stratosphere. Within 2-3 weeks, the stratospheric AO signal gradually propagated downward and accordingly the tropospheric AO evolved into the negative phase. Thus, a strong Ural blocking high developed, and cold air invaded Europe and East Asia from the polar region, which induced the decreasing temperature there. Our results suggest that improvements can be made in predicting severe winter cold events over Eurasia by taking into account the stratospheric circulation anomaly. |
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| Keywords: | Severe cold event during winter Arctic Oscillation Stratospheric circulation Planetary wave |
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