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孙淑清, 刘舸, 宋文玲, 彭京备. 中国东部冬季温度异常偶极型模态的一个前兆信号[J]. 大气科学, 2014, 38(4): 727-741. DOI: 10.3878/j.issn.1006-9895.2013.13211
引用本文: 孙淑清, 刘舸, 宋文玲, 彭京备. 中国东部冬季温度异常偶极型模态的一个前兆信号[J]. 大气科学, 2014, 38(4): 727-741. DOI: 10.3878/j.issn.1006-9895.2013.13211
SUN Shuqing, LIU Ge, SONG Wenling, PENG Jingbei. A Precursory Signal for the Dipole Mode of Winter Temperature Anomaly over Eastern China[J]. Chinese Journal of Atmospheric Sciences, 2014, 38(4): 727-741. DOI: 10.3878/j.issn.1006-9895.2013.13211
Citation: SUN Shuqing, LIU Ge, SONG Wenling, PENG Jingbei. A Precursory Signal for the Dipole Mode of Winter Temperature Anomaly over Eastern China[J]. Chinese Journal of Atmospheric Sciences, 2014, 38(4): 727-741. DOI: 10.3878/j.issn.1006-9895.2013.13211

中国东部冬季温度异常偶极型模态的一个前兆信号

A Precursory Signal for the Dipole Mode of Winter Temperature Anomaly over Eastern China

  • 摘要: 利用中国160站逐月温度、NCEP再分析、NOAA-CIRES 20世纪再分析以及NOAA海表温度等资料,分析了中国东部(100°E以东地区)冬季温度年际变化的主要模态,并重点研究了其中第2模态(即偶极型模态)的成因机理和前期信号。同时,也以2012~2013年冬季为例,探讨了这一温度异常模态的预测方法。研究主要发现:除中国东部大范围一致偏冷或偏暖模态以外,110°E以东的北方地区偏冷(暖)还经常对应着华南和110°E以西地区的偏暖(冷),构成温度异常反向变化的偶极型模态。这种偶极型模态也是冬季气候变化的一个主要模态,2012~2013年冬季温度异常即属于这一模态。中国东部冬季温度一致型模态主要与前期秋季中东太平洋海温异常、亚洲大陆北部积雪,及其邻近的北冰洋地区海冰密集度异常联系紧密。而对于偶极型模态,海温的影响并不明显,前期秋季的东亚中纬度地区积雪、北冰洋斯瓦尔巴群岛、法兰士约瑟夫地群岛附近海域的海冰密集度异常,以及它们引起的表面温度异常分布可能具有重要贡献,其中北冰洋海冰密集度异常导致的该地区表面温度异常的影响可能更为重要。综合了海冰和积雪信号的前期秋季北冰洋—东亚温度差异(Arctic Ocean-East Asian temperature contrast,简称AE)指数与中国东部冬季温度异常偶极型模态具有显著联系,可以作为一个重要的预测因子。2012年秋季赤道中东太平洋海温的正常状态以及北冰洋暖异常和东亚中纬度地区冷异常的表面温度分布特征,都不利于中国东部冬季温度南北一致型异常的发生,而是有利于偶极型异常分布。利用AE指数可以有效地预测2012~2013年中国东部冬季温度异常特征。

     

    Abstract: In this study, the dominant modes of winter temperature over eastern China (to the east of 100°E) are analyzed using the monthly temperature data recorded at 160 stations in China, National Centers for Environmental Prediction (NCEP) reanalysis data, National Oceanic and Atmospheric Administration-Cooperative Institute for Research in Environmental Sciences (NOAA-CIRES) 20th century reanalysis data, and NOAA Sea Surface Temperature (SST) data. The formation mechanism and precursory signals for the second (dipole) mode are primarily studied. Moreover, the prediction method for the second mode is explored by using the winter of 2012-2013 as an example. The results indicate that in addition to the unanimously colder or warmer first mode, the dipole mode, which is characterized as a colder (warmer) region over northern China and to the east of 110°E accompanied by a warmer (colder) region over southern China and to the west of 110°E, is also a main mode dominating the region over eastern China. The winter of 2012-2013 belongs to the second mode. The first mode is related mainly to the SST anomalies in the tropical eastern and central Pacific, the snow cover anomalies over the northern Asian continent, and the sea ice concentration anomalies in the Arctic Ocean along northern Asia during the previous autumn. For the second (dipole) mode, the SST anomalies have no clear influence; however the snow cover anomalies over the middle latitudes over East Asia, the sea ice concentration anomalies from the Svalbard archipelago to the Franz Josef Land archipelago of the Arctic Ocean during the previous autumn, and the surface air temperature pattern of the Arctic Ocean-East Asian temperature contrast caused by the aforementioned snow cover and sea ice anomalies seem to be important. The previous autumn Arctic Ocean-East Asian temperature contrast (AE) index, which involves the synthesized signals of snow cover and sea ice concentration, is closely related to the second mode and should be considered as an important predictor. In the autumn of 2012, several previous signals, such as the normal SST state in the equatorial Eastern and central Pacific, the warmer surface air temperature over the Arctic Ocean, and the colder surface air temperature over the middle latitudes of East Asia, are not conducive to the first mode but are favorable for the second (northern-colder-southern-warmer) mode. By using the previous AE index, the anomalous temperature pattern over eastern China in the winter of 2012-2013 can be effectively predicted.

     

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