Arctic sea ice albedo: Spectral composition, spatial heterogeneity, and temporal evolution observed during the MOSAiC drift

The magnitude, spectral composition, and variability of the Arctic sea ice surface albedo are key to understanding numerically simulating Earth’s shortwave energy budget. Spectral broadband albedos were spatially temporally sampled by on-ice observers along individual survey lines throughout sunlit season (April–September, 2020) during Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition. seasonal evolution MOSAiC year was constructed from averaged values each line. Specific locations identified as representative types, including accumulated dry snow, melting bare ice, refreezing ponded sediment-laden ice. area-averaged progression total recorded showed remarkable similarity that 22 years prior on multiyear Surface Heat Budget Ocean (SHEBA) In accord with these other previous field efforts, relatively thick, snow-free, shows invariance across location, decade, type. particular, indistinguishable second-year suggesting highly scattering layer forms summer is robust stabilizing. contrast, observed be variable at visible wavelengths. Notable temporal changes in documented melt freeze onset, formation deepening ponds, While model simulations show considerable agreement progression, disparities suggest need improve how both thin, simulated.