Abstract European monthly temperatures undergo strong fluctuations from one year to the other. The variability is controlled by natural processes such as Atlantic cycles, changes in solar activity, volcanic eruptions, unforced internal atmospheric variability, as well as anthropogenic factors. This contribution investigates the role of key natural drivers for European temperature variability, namely the Atlantic Multidecadal Oscillation (AMO), the North Atlantic Oscillation (NAO) and solar activity changes. We calculated Pearson correlation coefficients r for AMO, NAO and sunspots compared to monthly temperature data of 39 European countries for the period 1901–2015 in order to search for ‘fingerprints’ of the natural drivers. A cross correlation window of 11 months was chosen for AMO, NAO and of 120 months for SILSO to account for possible time lags or phase shifts. The r coefficients were mapped out across Europe on a monthly basis to document regional and seasonal changes of the correlation strength. The NAO dominates European temperature variability during the winter months, with strongest relationship in February. The AMO modulates temperatures in March to November, with best correlations occurring in summer, but also in April. Regions of strongest AMO and NAO impacts shift across the continent from month to month, forming systematic patterns. Direct correlation of the solar 11-year Schwabe cycle with temperatures was identified only in some countries in certain multidecadal intervals during February, March, June and September. Previous studies have suggested a significant solar influence on the AMO and NAO. It is likely that the greatest impact of solar activity on European temperatures is of a non-linear, indirect nature by way of interaction with Atlantic cycles.

中文翻译：

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欧洲温度的年代际和年代际自然变化

摘要 欧洲的月度温度从一年到另一年经历剧烈波动。可变性受大西洋循环、太阳活动变化、火山爆发、非受迫内部大气可变性以及人为因素等自然过程的控制。这项贡献调查了欧洲温度变化的关键自然驱动因素的作用，即大西洋多年涛动 (AMO)、北大西洋涛动 (NAO) 和太阳活动变化。我们计算了 AMO、NAO 和太阳黑子的 Pearson 相关系数 r 与 1901-2015 年期间 39 个欧洲国家的月度温度数据相比，以寻找自然驱动因素的“指纹”。为 AMO 选择了 11 个月的互相关窗口，NAO 和 SILSO 的 120 个月，以考虑可能的时间滞后或相移。r 系数按月在整个欧洲绘制，以记录相关强度的区域和季节性变化。NAO 在冬季月份主导着欧洲的温度变化，与 2 月份的关系最为密切。AMO 在 3 月至 11 月调节温度，最佳相关性发生在夏季，但也发生在 4 月。AMO 和 NAO 影响最强的区域逐月在整个大陆转移，形成系统模式。仅在某些国家在 2 月、3 月、6 月和 9 月期间的某些几十年间隔内，才确定了太阳 11 年施瓦贝周期与温度的直接相关性。先前的研究表明，太阳对 AMO 和 NAO 有显着影响。