Dominant trajectories and influenced regions of the near-surface cold air in the Arctic during positive and negative AO/NAM events
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摘要:
本文以拉格朗日观点分析北极涛动（Arctic Oscillation，AO），也被称为北半球环状模（Northern Hemisphere Annular Mode，NAM）的指数异常事件中北极近地面冷气团的活动路径，直接地表现出了异常事件中冷气团运动的优势路径，从而反映出AO/NAM对地面气温的直接调控作用.在正AO/NAM指数异常事件中，极区近地面冷气团活动轨迹以纬向环流为主，表现为环绕北半球中高纬地区的冷气团活动轨迹特征明显.而在负AO/NAM指数异常事件中，极区冷气团以反气旋式轨迹流出极区后，流入中纬度海洋上的低气压区，这种由极区向中纬度地区流动的经向运动轨迹特点显著.并且在指数下降的中后期出现两种强烈影响欧亚大陆的运动轨迹.正负事件中冷气团运动轨迹很好地解释了传统公认的AO/NAM对北半球不同地区冬季气温的影响.特别是对中国冬季气温的影响上，正AO/NAM指数异常事件中的中低层冷气团活动有利于南支槽加深，进而为南方地区冰冻雨雪天气提供了有利条件；而负事件中的极地近地面冷气团可直接影响东北地区，形成寒潮降温天气.
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关键词:
- 北极涛动/北半球环状模 /
- 冷空气优势路径 /
- 冬季气温
Abstract:The Arctic Oscillation (AO)/Northern Hemisphere Annular Mode (NAM) has a strong influence on weather and climate on different time scales, of which the intrinsic time scale is about 10~20 days. The synoptic time-scale variable of the AO/NAM determines its intrinsic and direct influence on weather. And usually extreme weather events occur corresponding to the abnormal AO/NAM indices. This is because the AO/NAM can modulate the movement of near-surface cold air in the Arctic that can affect the atmospheric circulation in the North Hemisphere and is the direct cause of cold surges and cold air outbreaks. Therefore, it is of great importance to investigate the motions of the near-surface cold air over the Polar under the modulation of the AO/NAM. Based on previous studies, we track trajectories of the near-surface air parcels pole ward of 60°N during AO/NAM events from the Lagrangian viewpoint. The dominant trajectories during the AO/NAM events are direct reflections of the AO/NAM's modulation to surface air temperature. During positive AO/NAM events, the near-surface atmospheric masses are restricted in the regions pole ward of 45°N. The air parcels converge in the regions of Aleutian islands and Norwegian Sea consistent with low pressure. The prominent feature of the cold air parcels during positive AO/NAM events is that latitudinal circulation prevails at middle and high latitudes, which limits the cold surge outbreak. During negative AO/NAM events, the air parcels flow out anticyclonically from the polar to the northern Pacific and Atlantic, respectively, especially in the valley of the AO/NAM index. Of particular importance, there are two dominant trajectories strongly influencing the Eurasian continent during the middle and later phases of the negative AO/NAM index decreasing stage. The trajectories of the near-surface air parcels over the polar match the correlation map of wintertime surface air temperature with the AO/NAM index very well and the results give a visualized interpretation of the AO/NAM's influence on weather. Also, near-surface air parcels during the positive and negative AO/NAM events exert different effects on northern and southern China. During positive AO/NAM events, the south-branch trough strengthens, which favors the transfer of cold air from mid-and high-latitude areas of Europe as well as water vapor from the Bay of Bengal to southern China, which results in conditions that favor the formation of cold waves and even frozen rain and snow in southern China. In comparison, during negative AO/NAM events, near-surface cold air in the eastern New Island and northern Iceland affect most of Europe and the easterly movement of these cold air masses directly affect northeastern China and key cold-wave regions. With the Siberian High and the East Asian Major Trough, the latter can cause temperature decreases, e.g., cold waves and strong winds, and further influence temperature in other regions of China.
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图 1
正负AO/NAM指数异常事件的AO/NAM指数合成
Figure 1.
Composite AO/NAM indexes of positive and negative AO/NAM events
图 2
(a) 轨迹质点出发点在地球表面等距离均匀的空间分布；(b)正AO/NAM指数异常事件中-10~-8天中冷气团轨迹在地球表面上的投影；(c)负AO/NAM指数异常事件中-10~-8天中冷气团轨迹在地球表面上的投影
Figure 2.
(a) Distribution in an equal spherical distance of starting dots on the Earth surface; (b) Projected trajectories of the cold air from lag -10 day to lag -8 day during the positive AO/NAM events; (c) Projected trajectories of the cold air from lag -10 day to lag -8 day during negative AO/NAM events
图 3
正AO/NAM指数异常事件(a~j)和负AO/NAM指数异常事件(k~t)中聚类分析后主要的冷气团质心轨迹在地球表面上的投影
Figure 3.
Dominant projected cluster centers of the cold air during positive AO/NAM events (a~j) and negative AO/NAM events (k~t)
图 4
正AO/NAM指数异常事件(a~f)和负AO/NAM指数异常事件(g~l)冷气团质心轨迹在地球表面上投影的示意图
Figure 4.
Schematic diagram depicting generalized features of dominant trajectories and surface temperature of the positive and negative AO/NAM events
图 5
冬季平均的AO/NAM指数与地面气温的相关系数分布
Figure 5.
Correlation efficients of winter-mean surface air temperature and AO/NAM index
图 6
正AO/NAM指数异常事件中指数下降阶段影响欧亚大陆地区的冷气团活动质心轨迹和700 hPa位势高度异常场
Figure 6.
Schematic diagram depicting dominant trajectories during early phase of the positive AO/NAM index decreasing stage
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Benedict J J, Lee S, Feldstein S B. 2004. Synoptic view of the North Atlantic Oscillation. Journal of the Atmospheric Sciences, 61(2): 121-144. doi: 10.1175/1520-0469(2004)061<0121:SVOTNA>2.0.CO;2
Ding Y H. 2005. Advanced Synoptic Meteorology. 2nd ed (in Chinese). Beijing: Meteorological Press, 256-266.
Feldstein S B. 2000. The timescale, power spectra, and climate noise properties of teleconnection patterns. J. Climate, 13(24): 4430-4440. doi: 10.1175/1520-0442(2000)013<4430:TTPSAC>2.0.CO;2
Feldstein S B. 2002. The recent trend and variance increase of the annular mode. J. Climate, 15(1): 88-94. doi: 10.1175/1520-0442(2002)015<0088:TRTAVI>2.0.CO;2
Feldstein S B. 2003. The dynamics of NAO teleconnection pattern growth and decay. Quarterly Journal of the Royal Meteorological Society, 129(589): 901-924. doi: 10.1256/qj.02.76
Feldstein S B, Franzke C. 2006. Are the North Atlantic oscillation and the Northern annular mode distinguishable?. Journal of the Atmospheric Sciences, 63(11): 2915-2930. doi: 10.1175/JAS3798.1
Gong D Y, Wang S W. 2003. Influence of arctic oscillation on winter climate over China. Acta Geographica Sinica (in Chinese), 58(4): 559-568. http://www.cnki.com.cn/Article/CJFDTotal-ZGDE200302010.htm
Kalnay E, Kanamitsu M, Kistler R, et al. 1996. The NCEP/NCAR 40-year reanalysis project. Bull. Amer. Meteor. Soc., 77(3): 437-471. http://intl-icb.oxfordjournals.org/external-ref?access_num=10.1175/1520-0477(1996)0772.0.CO;2&link_type=DOI
Kenyon J, Hegerl G C. 2008. Influence of modes of climate variability on global temperature extremes. J. Climate, 21(15): 3872-3889. doi: 10.1175/2008JCLI2125.1
Kenyon J, Hegerl G C. 2010. Influence of modes of climate variability on global precipitation extremes. J. Climate, 23(23): 6248-6262. doi: 10.1175/2010JCLI3617.1
Li L, Li C Y, Song J. 2012. Arctic Oscillation anomaly in winter 2009/2010 and its impacts on weather and climate. Sci. China Earth Sci., 55(4): 567-579, doi: 10.1007/s11430-011-4329-4.
Liang S J, Ding Y H, Zhao N, et al. 2014. Analysis of the Interdecadal Changes of the Wintertime Surface Air Temperature over Mainland China and Regional Atmospheric Circulation Characteristics during 1960-2013. Chinese Journal of Atmospheric Sciences (in Chinese), 38(5): 974-992, doi: 10.3878/j.issn.1006-9895.1401.13234.
Limpasuvan V, Hartmann D L. 1999. Eddies and the annular modes of climate variability. Geophysical Research Letters, 26(20): 3133-3136. doi: 10.1029/1999GL010478
Pan A D, Li Z X, Ni D H, et al. 2011. The 500 hPa circulation anomaly over Europe and its relationship with China climate anomaly in winter. Journal of the Meteorological Sciences (in Chinese), 31(2): 129-134. http://en.cnki.com.cn/Article_en/CJFDTotal-QXKX201102003.htm
Park T W, Ho C H, Yang S. 2011. Relationship between the Arctic Oscillation and cold surges over East Asia. J. Climate, 24(1): 68-83. doi: 10.1175/2010JCLI3529.1
Rigor I G, Wallace J M, Colony R L. 2002. Response of sea ice to the Arctic Oscillation. J. Climate, 15: 2648-2663. doi: 10.1175/1520-0442(2002)015<2648:ROSITT>2.0.CO;2
Sillmann J, Croci-Maspoli M. 2009. Present and future atmospheric blocking and its impact on European mean and extreme climate. Geophysical Research Letters, 36: L10702, doi: 10.1029/2009GL038259.
Suo M Q, Ding Y H. 2009. The structures and evolutions of the wintertime southern branch trough in the subtropical westerlies. Chinese Journal of Atmospheric Sciences (in Chinese), 33(3): 425-442. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=daqikx200903003
Tao S Y. 1957. A study of activities of cold airs in East Asian winter.//Chinese Meteorological Administration: Handbook of Short-Term Forecast (in Chinese).
Thompson D W J, Wallace J M. 1998. The Arctic Oscillation signature in the wintertime geopotential height and temperature fields. Geophysical Research Letters, 25(9): 1297-1300. doi: 10.1029/98GL00950
Thompson D W J, Wallace J M. 2001. Regional climate impacts of the Northern Hemisphere annular mode. Science, 293(5527): 85-89. doi: 10.1126/science.1058958
Wallace J M. 2000a. North Atlantic oscillation/annular mode: two paradigms-one phenomenon. Quarterly Journal of the Royal Meteorological Society, 126(564): 791-805. doi: 10.1256/smsqj.56401
Wallace J M. 2000b. On the Arctic and Antarctic Oscillations. NCAR Summer Colloquium Lecture Notes.
Wallace J M, Thompson D W J. 2002. The Pacific center of action of the Northern Hemisphere annular mode: Real or artifact?. J. Climate, 15(14): 1987-1991. doi: 10.1175/1520-0442(2002)015<1987:TPCOAO>2.0.CO;2
Wang L, Chen W. 2010. Downward Arctic Oscillation signal associated with moderate weak stratospheric polar vortex and the cold December 2009. Geophysical Research Letters, 37: L09707, doi: 10.1029/2010GL042659.
Wei J H, Lin Z H. 2009. The leading mode of wintertime cold wave frequency in northern China during the last 42 years and its association with Arctic Oscillation. Atmos. Oceanic Sci. Lett., 2(3): 130-134. doi: 10.1080/16742834.2009.11446794
Wu B Y, Wang J. 2002. Possible impacts of winter Arctic Oscillation on Siberian high, the East Asian winter monsoon and sea-ice extent. Advances in Atmospheric Sciences, 19(2): 297-320. http://link.springer.com/article/10.1007/s00376-002-0024-x
Zhang T F, Lu Y B, Zhang J, et al. 2006. Diagnostic analysis of a heavy snowstorm processe in Lower Latitude Plateau of China. Plateau Meteorology (in Chinese), 25(4): 696-703. http://en.cnki.com.cn/Article_en/CJFDTOTAL-GYQX200604017.htm
Zhang Z J, Qian W H. 2012. Precursors of regional prolonged low temperature events in China during winter half year. Chinese Journal of Atmospheric Sciences (in Chinese), 36(6): 1269-1279. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=daqikx201206015
Zhao N, Liang S J, Ding Y H. 2012. Coupling modes among action centers of wave-mean flow interaction and their association with the AO/NAM. J. Climate, 25(2): 447-458. doi: 10.1175/2011JCLI4240.1
Zhao N, Liang S J, Ding Y H. 2014. Underlying low-order dynamics of nonlinear interaction among Northern Hemisphere teleconnection patterns and its association with the AO/NAM. J. Climate, 27(3): 1315-1335. doi: 10.1175/JCLI-D-13-00356.1
Zhu Q G, Lin J R, Shou S W, et al. 1992. Weather Principles and Methods (in Chinese). Beijing: China Meteorological Press, 377-418.
丁一汇. 2005.高等天气学. 2版.北京:气象出版社, 256-266.
龚道溢, 王绍武. 2003.近百年北极涛动对中国冬季气候的影响.地理学报, 58(4): 559-568. doi: 10.3321/j.issn:0375-5444.2003.04.010
李琳, 李崇银, 宋洁. 2011. 2009/2010年冬季北极涛动异常及其影响分析.中国科学:地球科学, 41(12): 1771-1785. http://www.cqvip.com/QK/98491A/201112/40711768.html
梁苏洁, 丁一汇, 赵南等. 2014.近50年中国大陆冬季气温和区域环流的年代际变化研究.大气科学, 38(5): 974-992, doi: 10.3878/j.issn.1006-9895.1401.13234.
潘敖大, 李忠贤, 倪东鸿等. 2011.欧洲冬季500hPa环流异常及与中国气候异常的关系.气象科学, 31(2): 129-134. doi: 10.3969/j.issn.1009-0827.2011.02.002
索渺清, 丁一汇. 2009.冬半年副热带南支西风槽结构和演变特征研究.大气科学, 33(3): 425-442. doi: 10.3878/j.issn.1006-9895.2009.03.03
陶诗言. 1957.东亚冬季冷空气活动的研究.//中央气象局编.短期预报手册.
张腾飞, 鲁亚斌, 张杰等. 2006.一次低纬高原地区大到暴雪天气过程的诊断分析.高原气象, 25(4): 696-703. doi: 10.3321/j.issn:1000-0534.2006.04.018
张宗婕, 钱维宏. 2012.中国冬半年区域持续性低温事件的前期信号.大气科学, 36(6): 1269-1279. http://d.old.wanfangdata.com.cn/Periodical/daqikx201206015
朱乾根, 林锦瑞, 寿绍文等. 1992.天气学原理和方法.北京:气象出版社, 377-418.
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