The Effect of Arctic Vertical Warming on East Asia temperature variability on a monthly time scale and its predictability.

Recent studies have widely discussed arctic warming and its effect on the temperature variability over Eurasia. They agreed that Eurasia is cold while the arctic is warm during the boreal winter. Yet, the differences in month-to-month features and their predictability have not been examined. In this research, we categorized Arctic vertical warming into four types – Deep Arctic Warming (DAW), Shallow Arctic Warming (SAW), Arctic Warming Aloft, and Others – based on the vertical temperature distribution in the Barents-Kara Sea. And we discussed two significant events, DAW and SAW, which are closely related to the cold event over East Asia. The result shows that the temperature variability over East Asia associated with the Arctic events is significant in January and February but not in December. The multi-model ensemble of seasonal prediction models can distinguish the four types of Arctic events well than the individual models. In contrast, the individual models show better skill in reproducing the circulation patterns associated with the DAW than MME. Models tend to exhibit higher predictability over Eurasia in January and February compared to December. We suggest that this is partly due to the models' better representation of DAW in those months,  which is helpful for the better simulation of Arctic-midlatitude linkage.