Decomposing Shortwave Radiative Flux Variability in Terms of Surface and Atmospheric Contributions Using CERES Observations

Variations in both surface and atmospheric properties influence Earth's albedo. Here, we use simple diagnostic model of Earth’s albedo and CERES Energy Balanced and Filled (EBAF) Ed4.0 data for March 2000-February 2016 to quantify interannual variations in SW TOA flux associated with variations in surface albedo and variations in atmospheric reflectance and transmittance, primarily associated with clouds. Changes in Arctic surface albedo due mainly to variations in sea-ice concentration are examined from both a regional and global context. Surface albedo variations account for 4% of the total SW TOA flux variance globally, and < 1% in non-polar regions. Variations in atmospheric reflectance and transmittance account for 81% of the global SW TOA flux variance, with the remaining 15% explained by the co-variance of surface albedo and atmospheric reflectance/transmittance. Equatorward of 60-degree latitude, the atmospheric contribution exceeds that of the surface by at least an order-of-magnitude. In contrast, surface and atmospheric variations contribute equally poleward of 60S and surface variations account for twice as much as the atmosphere poleward of 60N. However, as much as 40% of the total SW TOA flux variance poleward of 60N is explained by the covariance of surface albedo and atmospheric reflectance/transmittance, highlighting the tight coupling between sea-ice concentration and cloud properties over the Arctic Ocean. The presentation will expand this analysis to regional and seasonal space-time scales and will examine trends in surface and atmospheric contributions in the context of declining Arctic sea-ice concentration since 2000.