| 冬季斯堪的纳维亚遥相关型在20世纪70年代末的年代际变化 |
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| 引用本文： | 刘毓赟,王林.冬季斯堪的纳维亚遥相关型在20世纪70年代末的年代际变化[J].气候与环境研究,2014,19(3):371-382. |
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| 作者姓名： | 刘毓赟 王林 |
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| 作者单位： | 中国科学院大气物理研究所季风系统研究中心, 北京100190;中国科学院大学, 北京100049;中国科学院大气物理研究所季风系统研究中心, 北京100190 |
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| 基金项目： | 公益性（气象）行业专项项目GYHY201406018，国家自然科学基金项目41230527、41025017 |
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| 摘 要： | 利用NCEP/NCAR再分析资料和PREC-L(Precipitation Reconstruction over Land)降水资料分析了1948/1949~2008/2009年冬季斯堪的纳维亚(SCAND)遥相关型的年代际变化,并讨论了这次年代际变化前后SCAND型的不同时空特征、气候影响及其维持机制。结果表明,SCAND型在1979年前后发生了明显的年代际突变,其500 hPa高度场上的欧洲中心和西伯利亚中心在1979年之后均向东南方向移动,但斯堪的纳维亚半岛附近的中心位置没有明显变化。与此相对应,1979年之后SCAND型对北半球气温的影响有很大加强,主要表现为其正(负)位相引起的极区增温范围明显扩大,欧亚大陆北部的温度负(正)中心显著向东南方向延伸,甚至可以影响到我国长江流域和日本的温度变化。1979年之后,SCAND型正(负)位相可以引起欧亚大陆沿60°N左右纬度带的降水显著减少(增加),这与1979年之前SCAND型主要引起乌拉尔山以西地区的降水变化有所不同。对准地转位势倾向方程的诊断表明,SCAND型在1979年前后的年代际变化基本可以用异常定常波引起的涡度强迫、异常定常波与气候态定常波相互作用引起的涡度强迫以及高频瞬变波引起的涡度强迫三者的变化来解释。
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| 关 键 词： | 斯堪的纳维亚遥相关型 年代际变化 气候突变 |
| 收稿时间： | 2013/3/27 0:00:00 |
| 修稿时间： | 2013/8/27 0:00:00 |
Interdecadal Changes of Scandinavian Teleconnection Pattern in the Late 1970s |
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| LIU Yuyun and WANG Lin.Interdecadal Changes of Scandinavian Teleconnection Pattern in the Late 1970s[J].Climatic and Environmental Research,2014,19(3):371-382. |
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| Authors: | LIU Yuyun and WANG Lin |
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| Institution: | Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100190
;University of Chinese Academy of Sciences, Beijing 100049;Center for Monsoon System Research, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100190 |
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| Abstract: | Based on the reanalysis dataset from the National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) and the Precipitation Reconstruction over Land (PREC-L) dataset, this study investigates the interdecadal changes of the Scandinavian (SCAND) teleconnection pattern in boreal winter. The SCAND pattern is obtained by applying the rotated empirical orthogonal function (REOF) method on the winter mean 500-hPa geopotential height anomalies for the period from 1948/1949 to 2008/2009. The SCAND pattern consists of three primary centers of actions. One is located around the Scandinavian Peninsula and the other two have opposite signs and are located over Western Europe and Siberia, respectively. Analysis of the SCAND index reveals that the SCAND pattern was in its decadal negative phase around 1960, and from the late 1970s to the early 2000s. Its decadal positive phase occurred in the 1950s, from the early 1960s to the late 1970s, and again in recent years. A Lepage test indicates that the SCAND pattern experienced a clear abrupt change in 1979. Further analysis indicates that the centers of both SCAND patterns over Western Europe and Siberia extended further southeastward during the 1979/1980 to 2008/2009 period, as compared with those in the 1948/1949 to 1978/1979 period. The center over the Scandinavian Peninsula, however, showed little change. Accompanied with the changes in spatial pattern, the influences of SCAND pattern on the wintertime surface air temperature and precipitation also changed. For the period between 1979/1980 and 2008/2009, negative surface air temperature anomalies associated with the positive phase of the SCAND pattern over the northern Eurasian continent extended further southeastward, even reaching the lower reaches of the Yangtze River Valley and Japan. Meanwhile, the negative precipitation anomalies associated with the positive phase of SCAND pattern featured a zonally elongated band over the Eurasian continent centered at about 60°N, in contrast to the situation before 1979. Diagnostics using the geopotential height tendency equation suggest that the interdecadal changes in the SCAND pattern can be attributed to the changes in vorticity forcing by anomalous stationary waves, interactions between anomalous and climatological stationary waves, and high-frequency transient eddies. |
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| Keywords: | Scandinavian teleconnection Interdecadal variation Climate shift |
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