The Arctic warming response to rising greenhouse fuel is considerably higher than the remainder of the globe. It has been recommended that this phenomenon, generally known as Arctic amplification, and its peak in boreal fall and winter end result primarily from the so-called lapse-rate suggestions, which is related to the vertical construction of tropospheric warming, relatively than from the sea-ice albedo suggestions, which operates primarily in boreal summer time. Nonetheless, future local weather mannequin projections present persistently that an total discount of sea-ice within the Arctic area results in a gradual weakening of Arctic amplification, thereby implying a key position for sea-ice albedo suggestions. To resolve this obvious contradiction, a brand new examine accepted in Earth’s Future carried out a complete evaluation utilizing atmosphere-ocean reanalysis datasets and quite a lot of local weather mannequin simulations. This examine confirmed that the Arctic Ocean acts as a warmth capacitor, storing anomalous warmth ensuing from the sea-ice loss throughout summer time, which is then launched again into the environment throughout fall and winter. The ocean heat-driven sturdy air-sea warmth fluxes in fall and winter in sea-ice retreat areas together with a stably stratified decrease troposphere result in a surface-intensified warming and moistening, augmenting longwave suggestions processes to additional improve the pronounced Arctic warming within the chilly season. These outcomes strongly counsel that the warm-season ocean warmth recharge and cold-season warmth discharge hyperlink and combine the nice and cozy and chilly season feedbacks, and thereby successfully clarify the predominance of the Arctic amplification in fall and winter.
Determine 8 from Chung et al. (2020): A schematic diagram illustrating the contribution of anomalous seasonal ocean warmth uptake and launch to fall and winter Arctic amplification. The higher ocean shops warmth ensuing from GHG-induced sea-ice loss throughout summer time, and the amassed warmth is then launched again into the environment throughout fall and winter. Attributable to a steady situation within the lowermost a part of the environment through the chilly season, a big fraction of the warmth and moisture launched from sea-ice retreat areas is trapped in that layer. The surface-intensified warming and moistening in flip acts to additional promote LW suggestions processes, together with the lapse-rate suggestions, to reinforce the warming.
Chung, E.S., Ha, Okay.J., Timmermann, A., Stuecker, M.F., Bodai, T., & Lee, S.-Okay. (2020). Chilly‐Season Arctic Amplification Pushed by Arctic Ocean‐Mediated Seasonal Power Switch. Earths Future, 8, e2020EF001898 https://doi.org/10.1029/2020EF001898.