Cold Eurasian winter in recent decade: Is it caused by Arctic sea ice?
Seok-Woo Son1, Hye-Jin Kim1, Baek-Min Kim2, Jong-Seong Kug3, Jee-Hoon Jeong4, Jinho Yoon5
1 Seoul National University, Seoul, Rep. of Korea
2 Korea Polar Research Institute, Incheon, Rep. of Korea
3 Pohang University of Science and Technology (POSTECH), Pohang, Rep. of Korea
4 Chonnam National University, Gwangju, Rep. of Korea
5 Gwangju Institute of Science and Technology (GIST), Gwangju, Rep. of Korea
Surface air temperature in the northern mid-latitudes has shown a significant cooling trend in recent winters in spite of increasing greenhouse gas concentrations. Such an unexpected cooling was particularly strong across Eurasia, and this has been partly attributed to Arctic sea ice loss. Here, by performing statistical analyses and climate model experiments, the possible link between Arctic and Eurasian temperature, often referred to as Warm Arctic-Cold Eurasia (WACE) pattern, is re-visited.
A significant time-lagged co-variability is observed between Arctic autumn sea ice concentrations and Eurasian winter surface air temperature. More importantly, the timing of abrupt Arctic sea ice loss is consistent with the timing of Eurasian cooling. These results suggest that both short-term variability and long-term trend of Eurasian winter temperature are likely influenced by Arctic sea ice. Climate model simulations, however, do not fully support this conjecture. While some models, forced by Arctic sea ice loss, successfully reproduce the Eurasian winter cooling, others fail to simulate cooling trend. This clearly indicates that WACE pattern is not robust and its causal relationship is quite uncertain.