Cross-seasonal Regulation Mechanism of Arctic Sea Ice on Mid-latitude Eurasian Weather Fluctuations from an Energetic Perspective

The Arctic is warming at a rate far exceeding the global average, accompanied by a dramatic decline in sea ice extent. Its impact on the weather and climate over the densely populated mid-latitude Eurasia has long been a core and highly controversial scientific issue in climate dynamics. Limited by bottlenecks such as subjective metrics and low signal-to-noise ratio, previous studies have not reached a consensus on the existence and physical mechanism of this linkage. Most focused on winter processes, while dynamic analysis of cross-seasonal regulation in summer remains particularly insufficient.

This study adopts eddy kinetic energy (EKE) and eddy available potential energy (EAPE) as objective dynamic metrics to quantify circulation and temperature fluctuations associated with weather patterns, and systematically reveals the cross-seasonal regulation of Arctic sea ice on weather fluctuations over mid-latitude Eurasia. The results show that sea ice loss in key regions such as the Barents-Kara Sea in early autumn can lead to a significant enhancement of low-frequency eddy energy over northern Eurasia in the subsequent winter via southward energy propagation of polar low-frequency Rossby waves, corresponding to more frequent persistent weather events, while weakened local baroclinicity suppresses synoptic eddy activities. Further evidence confirms that the Barents-Kara Sea ice anomaly in the preceding February can drive southward propagation of 10-30-day low-frequency waves through the cross-seasonal memory of subpolar North Atlantic sea surface temperature anomalies, superimposed with the meridional amplification of mid-summer circulation, thus significantly modulating subseasonal temperature fluctuations in central Asia in August. This study clarifies the winter-summer seasonal differences of the Arctic-midlatitude teleconnection, and provides a critical Arctic predictability source for extended-range to subseasonal prediction of Eurasian weather and climate.