An Overview of the Centennial Progress in Research on the Arctic-Midlatitude Connection

This paper provides a brief summary of the representative research outcomes on the Arctic-midlatitude connection since the founding of the Chinese Meteorological Society in 1924: （1）The revelation of the North Atlantic Oscillation, the Arctic Oscillation, and the Arctic Dipole anomaly represents three significant milestones in the study of large-scale Arctic-midlatitude teleconnections. （2）Before the mid-1990s, Chinese scholars revealed the key pathways by which Arctic cold air affects cold wave processes in East Asia, the key areas for cold waves, and the dynamical processes of cold high pressure during cold waves. These findings are outstanding representatives of Arctic-midlatitude connection research and have profoundly influenced the development of meteorology in China and the prediction of cold wave processes in winter.（3）The melting of Arctic sea ice and Arctic warming anomalies influence mid-latitude weather events and climate variations by affecting the evaporation of water vapor from the ocean surface, turbulent heat flux between atmosphere and ocean, the meridional temperature gradient of the atmosphere, zonal winds, the path and intensity of the storm track, the propagation of large-scale horizontal teleconnection patterns and planetary waves between the troposphere and stratosphere.（4）The melting of Arctic sea ice plays important roles in modulating the interdecadal variations of the winter atmospheric circulation, leading to alternative occurrence of a warm Arctic-cold Eurasia (2004/05-2012/13) and a warm Arctic-warm Eurasia (2013/14-2018/19). The former strengthens the connection between the Arctic and mid-latitudes, while the latter corresponds to a noticeable weakening of the Arctic-mid-latitude connection.（5）The melting of Arctic sea ice facilitates the frequent occurrence of Arctic cold anomalies in the middle and lower troposphere during summer, leading to the formation of blocking circulation anomalies in high-latitude regions that are conducive to the occurrence of heatwaves and wildfires in some regions of high-latitudes.（6）The frequency of summer heatwaves averaged over the Tibetan Plateau to the mid and low latitude areas of eastern China has a direct dynamical link with the frequent occurrence of summer Arctic cold anomalies in the middle and lower troposphere. The systematic northward shift of the troposphere zonal winds over East Asia is the intrinsic mechanism that connects the Arctic cold anomalies with the heatwaves in East Asia. Future research on Arctic-midlatitude connections should pay more attention to the role of Arctic sea ice melting in the low-frequency variability of atmospheric circulation, particularly emphasizing the impacts of both different spatial anomalies and anomalous amplitudes in Arctic sea ice concentrations. It is necessary to quantitatively examine the role of Arctic sea ice melting in extreme weather and climate events.