Roy Indrani
University of Exeter, Exeter, EX4 4QE, UK.
Sci Rep. 2018 Mar 20;8(1):4864. doi: 10.1038/s41598-018-22854-0.
This study investigates the role of the eleven-year solar cycle on the Arctic climate during 1979-2016. It reveals that during those years, when the winter solar sunspot number (SSN) falls below 1.35 standard deviations (or mean value), the Arctic warming extends from the lower troposphere to high up in the upper stratosphere and vice versa when SSN is above. The warming in the atmospheric column reflects an easterly zonal wind anomaly consistent with warm air and positive geopotential height anomalies for years with minimum SSN and vice versa for the maximum. Despite the inherent limitations of statistical techniques, three different methods - Compositing, Multiple Linear Regression and Correlation - all point to a similar modulating influence of the sun on winter Arctic climate via the pathway of Arctic Oscillation. Presenting schematics, it discusses the mechanisms of how solar cycle variability influences the Arctic climate involving the stratospheric route. Compositing also detects an opposite solar signature on Eurasian snow-cover, which is a cooling during Minimum years, while warming in maximum. It is hypothesized that the reduction of ice in the Arctic and a growth in Eurasia, in recent winters, may in part, be a result of the current weaker solar cycle.
本研究调查了1979 - 2016年期间11年太阳周期对北极气候的作用。研究表明，在那些年份里，当冬季太阳黑子数（SSN）低于1.35个标准差（或平均值）时，北极变暖从对流层低层延伸到平流层高层；反之，当SSN高于该值时则相反。大气柱中的变暖反映出一种东风带异常，对于SSN最低的年份，这种异常与暖空气和正位势高度异常一致，而对于SSN最高的年份则相反。尽管统计技术存在固有局限性，但合成分析、多元线性回归和相关性分析这三种不同方法均表明，太阳通过北极涛动途径对冬季北极气候具有类似的调制影响。通过展示示意图，本文讨论了太阳周期变化通过平流层途径影响北极气候的机制。合成分析还在欧亚大陆积雪上检测到相反的太阳信号，即太阳活动极小年期间出现降温，而在极大年期间出现升温。据推测，近年来冬季北极冰层的减少和欧亚大陆积雪的增加，可能部分是当前太阳周期较弱的结果。
