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贾丹, 简茂球. 中国冬季月地面气温的年际变化[J]. 气候与环境研究, 2015, 20(4): 454-464. DOI: 10.3878/j.issn.1006-9585.2015.14240
引用本文: 贾丹, 简茂球. 中国冬季月地面气温的年际变化[J]. 气候与环境研究, 2015, 20(4): 454-464. DOI: 10.3878/j.issn.1006-9585.2015.14240
JIA Dan, JIAN Maoqiu. Interannual Variability of Wintertime Monthly Surface Air Temperature in China[J]. Climatic and Environmental Research, 2015, 20(4): 454-464. DOI: 10.3878/j.issn.1006-9585.2015.14240
Citation: JIA Dan, JIAN Maoqiu. Interannual Variability of Wintertime Monthly Surface Air Temperature in China[J]. Climatic and Environmental Research, 2015, 20(4): 454-464. DOI: 10.3878/j.issn.1006-9585.2015.14240

中国冬季月地面气温的年际变化

Interannual Variability of Wintertime Monthly Surface Air Temperature in China

  • 摘要: 基于观测资料和再分析资料,对我国冬季各月地面气温的年际变异时空演变以及它们之间的相互关系、相关的环流异常特征进行了统计诊断分析,并对大气内部的影响过程和机制进行解释。我国冬季各月地面气温的主要年际变异模态是除青藏高原地区外的全国一致型,其次为南北反号分布型。我国冬季1月与2月气温的主要年际变异模态之间存在显著的同相变化关系,而它们与前期12月气温的主要变异型存在一定程度的反相变化关系。我国冬季各月地面气温主要年际变异模态又与欧亚大陆更大范围的高纬—中低纬度地区气温的反号变异型直接相关。与我国冬季各月大范围的地面气温变异相关的温度异常信号存在于深厚的对流层,其中异常信号在地面最显著,其强度随高度逐渐衰减。地表温度异常可以通过地表向上长波辐射通量异常来影响近地面乃至更高层次的气温异常。在冬季各月,欧亚大陆北部上空对流层各层出现的明显西风异常加强,使得高纬度的冷空气南侵活动减弱,从而造成我国乃至更大范围且垂直深厚的气温暖异常。

     

    Abstract: Based on observed and reanalysis data, this study analyzes the spatiotemporal variations of monthly surface temperature in winter in China, their interrelationship, and the related anomalous circulation on the interannual timescale. The atmospheric internal mechanisms for the interannual variation of surface temperature is also discussed. The dominant interannual mode is uniform across China, except in the Tibetan Plateau, for all winter months, while the second mode is a north-south dipole mode with opposite sign. The dominant interannual modes of surface temperature in January and February are closely correlated to each other in phase, but are to some extent negatively correlated with that in the prior December. The dominant interannual modes of monthly surface temperature in winter are also linked to the opposite-sign dipole anomalous patterns of surface temperature in the Eurasian continent. The anomalous temperature signals associated with the nationwide winter surface temperature anomalies may extend up to high levels in the troposphere, with the most intense signals at the surface. The surface temperature anomalies may induce the air temperature anomalies from the near surface to the upper troposphere via the upward longwave radiation flux anomalies emitted from the underlying surface. In all winter months, the intensified westerly over the northern Eurasian continent hinders the southward intrusion of cold air from high latitudes, and then results in a deep warm anomaly over winter in China, and an even larger part of the Eurasian continent.

     

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