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刘扬, 刘屹岷. 斯堪的纳维亚遥相关对我国西南西部深秋降水的影响[J]. 气候与环境研究, 2017, 22(1): 80-88. DOI: 10.3878/j.issn.1006-9585.2016.16029
引用本文: 刘扬, 刘屹岷. 斯堪的纳维亚遥相关对我国西南西部深秋降水的影响[J]. 气候与环境研究, 2017, 22(1): 80-88. DOI: 10.3878/j.issn.1006-9585.2016.16029
Yang LIU, Yimin LIU. The Impact of the Scandinavian Teleconnection Pattern on Late Autumn Rainfall in the Western Region of Southwest China[J]. Climatic and Environmental Research, 2017, 22(1): 80-88. DOI: 10.3878/j.issn.1006-9585.2016.16029
Citation: Yang LIU, Yimin LIU. The Impact of the Scandinavian Teleconnection Pattern on Late Autumn Rainfall in the Western Region of Southwest China[J]. Climatic and Environmental Research, 2017, 22(1): 80-88. DOI: 10.3878/j.issn.1006-9585.2016.16029

斯堪的纳维亚遥相关对我国西南西部深秋降水的影响

The Impact of the Scandinavian Teleconnection Pattern on Late Autumn Rainfall in the Western Region of Southwest China

  • 摘要: 使用中国台站降水数据和NCEP/NCAR再分析资料,分析了1961~2012年深秋斯堪的纳维亚遥相类型(SCA)与同期我国西南西部降水的关系,以及SCA型环流异常影响西南西部降水的具体物理过程。结果表明:SCA型遥相关与西南西部降水存在显著的负相关关系,且具有非对称性:SCA正位相时西南西部降水偏少,而SCA负位相与西南西部降水的关系不显著。SCA正位相年西南西部的降水偏少与该地区对流层中下层的异常下沉运动有关。垂直运动方程诊断结果表明该异常下沉运动主要是由冷平流异常维持。气候态风场对温度异常场的平流在西南西部的冷平流异常中起主要作用。SCA正位相时,西南西部地区的东侧有暖异常,而其西侧的印度半岛北部及伊朗高原地区为冷异常,在平均西风作用下,西南西部有冷平流异常,造成该地区的异常下沉运动,从而降水偏少。

     

    Abstract: Based on rainfall datasets obtained from meteorological stations in China and the NCEP/NCAR reanalysis data, the simultaneous relationship between the Scandinavian teleconnection pattern (SCA) and late autumn precipitation over the western region of Southwest China (WSWC) during 1961-2012 is investigated. Results show that there is a significant negative correlation between the SCA index and the rainfall over WSWC. The negative correlation is asymmetric. During the positive SCA years, the rainfall in WSWC is less than that in normal years. However, during the negative SCA years, the relationship between the SCA index and the rainfall over WSWC is not significant. The negative rainfall anomaly over WSWC during positive SCA years is consistent with local anomalous descending motion in the lower and middle troposphere. The diagnostic analysis of the vertical motion equation indicates that the local descending motion is primarily maintained by anomalous cold temperature advection. The advection of anomalous temperature by mean westerlies contributes most to the anomalous cold temperature advection in WSWC. The downstream Rossby wave propagation triggered by the positive SCA pattern weakens the East Asian trough. Consequently, the eastern part of Southwest China becomes warmer. The climatological westerly wind brings anomalously cold air into the WSWC area, resulting in local descending motion and drought.

     

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