Abstract By analyzing NCEP-NCAR reanalysis daily data for 1979–2016, the modulation by Madden-Julian Oscillation (MJO) of the wintertime surface air temperature (SAT) over high latitude is examined. The real-time multivariate MJO (RMM) index, which divides the MJO into eight phases, is used. It is found that a significantly negative SAT anomaly over the northern high latitude region of (180°–60 °W, 60°–90 °N) lags the MJO convection for 1∼2 weeks in phase 3, in which the enhanced convective activity exists over the Indian Ocean. While a significantly positive SAT anomaly appears over the same region following the MJO phase 7, as the tropical heating shows an opposite sign. Analysis of the anomalous circulation indicates that the observed SAT signal is probably a result of the northeastward propagating Rossby wave train triggered by MJO-related tropical forcing through Rossby wave energy dispersion. By using an anomalous atmospheric general circulation model (AGCM), the significant effect of tropical forcing on organizing the extratropical circulation anomaly is confirmed. Analysis of a temperature tendency equation further reveals that the intraseasonal SAT anomaly is primarily attributed to the advection of the mean temperature by the wind anomaly associated with the anomalous circulation of the MJO-related variability.

中文翻译：

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北方冬季马登-朱利安振荡对高纬度地表气温的影响

摘要 通过分析 1979-2016 年 NCEP-NCAR 再分析日数据，研究了 Madden-Julian Oscillation (MJO) 对高纬度地区冬季地表气温 (SAT) 的调制。使用实时多元 MJO (RMM) 指数，将 MJO 分为八个阶段。发现北部高纬地区（180°-60°W, 60°-90°N）的SAT显着负异常在第3阶段滞后MJO对流1~2周，其中对流活动增强存在于印度洋上空。在 MJO 阶段 7 之后，同一区域出现显着正的 SAT 异常，因为热带加热显示出相反的迹象。对异常环流的分析表明，观测到的卫星信号可能是由与 MJO 相关的热带强迫通过罗斯比波能量色散引发的向东北传播的罗斯比波列的结果。通过使用异常大气环流模式（AGCM），证实了热带强迫对组织温带环流异常的显着影响。温度趋势方程的分析进一步表明，季节内SAT异常主要归因于与MJO相关变异性异常环流相关的风异常对平均温度的平流。证实了热带强迫对组织温带环流异常的显着影响。温度趋势方程的分析进一步表明，季节内SAT异常主要归因于与MJO相关变异性异常环流相关的风异常对平均温度的平流。证实了热带强迫对组织温带环流异常的显着影响。温度趋势方程的分析进一步表明，季节内SAT异常主要归因于与MJO相关变异性异常环流相关的风异常对平均温度的平流。