In January 2016, the Arctic experienced an extremely anomalous warming event after an extraordinary increase in air temperature at the end of 2015. During this event, a strong intrusion of warm and moist air and an increase in downward longwave radiation, as well as a loss of sea ice in the Barents and Kara seas, were observed. Observational analyses revealed that the abrupt warming was triggered by the entry of a strong Atlantic windstorm into the Arctic in late December 2015, which brought enormous moist and warm air masses to the Arctic. Although the storm terminated at the eastern coast of Greenland in late December, it was followed by a prolonged blocking period in early 2016 that sustained the extreme Arctic warming. Numerical experiments indicate that the warming effect of sea ice loss and associated upward turbulent heat fluxes are relatively minor in this event. This result suggests the importance of the synoptically driven warm and moist air intrusion into the Arctic as a primary contributing factor of this extreme Arctic warming event.

Intense storms have been more frequently observed in the Arctic during recent years, in coincidence with extreme sea ice loss events. However, it is still not fully understood how storms drive such events due to deficient observations and modeling discrepancies. Here we address this problem by analyzing in situ observations acquired during an Arctic expedition, which uniquely captured an intense storm in summer 2016. The result shows a pronounced acceleration of sea ice loss during the storm process. Diagnostic analysis indicates a net energy loss at the ice surface, not supporting the accelerated melting. Although the open water surface gained net heat energy, it was insufficient to increase the mixed‐layer temperature to the observed values. Dynamic analysis suggests that storm‐driven increase in ocean mixing and upward Ekman pumping of the Pacific‐origin warm water tremendously increased oceanic heat flux. The thermal advection by the Ekman pumping led to a warmed mixed layer by 0.05°C–0.12°C and, in consequence, an increased basal sea ice melt rate by 0.1–1.7 cm day⁻¹.

In the Northwestern Pacific, the meridionally propagating Rossby waves, known as the Pacific‐Japan (PJ) pattern, is the dominant teleconnection pattern and is considered as a source of heatwaves in East Asia. In this study, the circulation and thermodynamic characteristics of these patterns were investigated based on daily timescale to evaluate their relationship with the likelihood of heatwaves in Korea and Japan. The investigations reveal that stations in Korea and Japan record approximately 90% increase in extremely hot days (T_max > 35°C) during the positive PJ pattern events. According to thermodynamic budget, horizontal heat advection is a key factor for the observed near‐surface warming during the positive PJ. The circulation pattern during the positive PJ largely explains the enhanced warm advection and physical heating due to the increased insolation and adiabatic heating are secondary factors for near‐surface warming. This phenomenon is robustly observed regardless of the definition.

The harmony of the Southern Ocean and Antarctic terrain is the pacemaker of Antarctic climate change under global warming.