Quantifying the Role of Atmospheric and Surface Albedo on Polar Amplification Using Satellite Observations and CMIP6 Model Output

Abstract

AbstractUnderstanding polar amplification (PA) and its underlying processes is key to accurately predicting the climate system's response to increasing anthropogenic forcings. We examine the amplified warming in the Arctic and Antarctic in 17 global climate models from the Coupled Model Intercomparison Project 6 (CMIP6) against satellite data. Large hemispheric differences in PA strength was found in the CMIP6 models. Changes in surface temperature and strength of PA is closely coupled to changes in albedo. The planetary albedo of Earth (αp) is partitioned into a component associated with surface albedo (defined as surface contribution to planetary albedo, ), and a component associated with atmospheric albedo (atmospheric contribution to planetary albedo, ). To assess the hemispheric differences in PA strengths, the relative importance of and were investigated. The surface reflection looks different as seen at the surface (defined as surface albedo, αsurf) compared to (as seen at the top of the atmosphere). We find a stronger correlation between surface temperature and αsurf in the Arctic than in the Antarctic, with correlation coefficients of −0.94 and −0.88, respectively. Interestingly, the correlation for surface temperature and is stronger in the Antarctic than in the Arctic with correlation coefficients of −0.93 and −0.90, respectively. In the southern high latitudes, albedo changes at the surface are more important than changes in the atmosphere, while the opposite applies in the northern high latitudes. Surface temperature changes in the low‐ and mid‐latitudes are strongly associated with changes in , dominated by changes in cloud properties.