Kim Hye-Jin, Son Seok-Woo, Moon Woosok, Kug Jong-Seong, Hwang Jaeyoung
School of Earth and Environmental Sciences, Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, 08826, South Korea.
Department of Mathematics, Stockholm University, Stockholm, Sweden.
Sci Rep. 2021 Feb 18;11(1):4081. doi: 10.1038/s41598-021-83486-5.
The subseasonal relationship between Arctic and Eurasian surface air temperature (SAT) is re-examined using reanalysis data. Consistent with previous studies, a significant negative correlation is observed in cold season from November to February, but with a local minimum in late December. This relationship is dominated not only by the warm Arctic-cold Eurasia (WACE) pattern, which becomes more frequent during the last two decades, but also by the cold Arctic-warm Eurasia (CAWE) pattern. The budget analyses reveal that both WACE and CAWE patterns are primarily driven by the temperature advection associated with sea level pressure anomaly over the Ural region, partly cancelled by the diabatic heating. It is further found that, although the anticyclonic anomaly of WACE pattern mostly represents the Ural blocking, about 20% of WACE cases are associated with non-blocking high pressure systems. This result indicates that the Ural blocking is not a necessary condition for the WACE pattern, highlighting the importance of transient weather systems in the subseasonal Arctic-Eurasian SAT co-variability.
利用再分析数据重新审视了北极与欧亚大陆地表气温（SAT）之间的亚季节关系。与之前的研究一致，在11月至2月的寒冷季节观察到显著的负相关，但在12月下旬出现局部最小值。这种关系不仅由暖北极 - 冷欧亚（WACE）模式主导，该模式在过去二十年中变得更加频繁，还由冷北极 - 暖欧亚（CAWE）模式主导。预算分析表明，WACE和CAWE模式主要由与乌拉尔地区海平面气压异常相关的温度平流驱动，部分被非绝热加热抵消。进一步发现，尽管WACE模式的反气旋异常大多代表乌拉尔阻塞，但约20%的WACE情况与非阻塞高压系统有关。这一结果表明，乌拉尔阻塞不是WACE模式的必要条件，突出了瞬变天气系统在亚季节北极 - 欧亚SAT共变率中的重要性。
