Characteristics and formation mechanisms of Arctic amplification: progress, challenges and ways forwardOA

In recent decades, the Arctic has experienced persistent warming, with near-surface warming three to four times higher than the global average, accompanied by the melting of sea ice, snow cover, and ice sheets. This anomalous warming phenomenon is referred to as Arctic amplification(referred to as AA). With the recent advances in AA research, significant understanding has been developed regarding its temporal evolution, spatial distribution, and influencing mechanisms. However, controversies remain concerning the primary drivers of AA, the quantitative contributions of various drivers, and some of the underlying processes. This paper synthesizes recent research findings, revisiting the spatiotemporal characteristics of AA and its driving factors, and analyzes the influencing mechanisms from four perspectives, including albedo feedback, temperature feedback, aerosol–water vapor–cloud feedback, and poleward energy transport via ocean and atmosphere circulation. Existing studies are summarized to several major conclusions, including: AA is characterized by a short emergence time(appearing in the last ~40 years), a strong influence from underlying surface properties, albeit with significant seasonal variations;AA is influenced by a combination of drivers both within and outside the Arctic, and the interactions among these factors are highly complex, preventing a conclusive, overarching understanding of the formation mechanisms from being established. We suggest that future research would benefit from the following three key foci:(1) enhancing studies on the impacts of land surface albedo feedback, aerosols, the Atlantic Meridional Overturning Circulation, and stratospheric processes on AA;(2) optimizing parameterizations of cloud–aerosol and land surface processes in climate and Earth system models, and integrating sea ice drift dynamics into these models;and(3) investigating the interactive mechanisms among various driving factors from a holistic perspective.