Linking Radiative‐Advective Equilibrium Regime Transition to Arctic Amplification

Abstract Emission of anthropogenic greenhouse gases has resulted in greater Arctic warming compared to global warming, known as Arctic amplification (AA). From an energy‐balance perspective, the current Arctic climate is in radiative‐advective equilibrium (RAE) regime, in which radiative cooling is balanced by advective heat flux convergence. Exploiting a suite of climate model simulations with varying carbon dioxide (CO2) concentrations, we link the northern high‐latitude regime variation and transition to AA. The dominance of RAE regime in northern high‐latitudes under CO2 reduction relates to stronger AA, whereas the RAE regime transition to non‐RAE regime under CO2 increase corresponds to a weaker AA. Examinations on the spatial and seasonal structures reveal that lapse‐rate and sea‐ice processes are crucial mechanisms. Our findings suggest that if CO2 concentration continues to rise, the Arctic could transition into a non‐RAE regime accompanied with a weaker AA.