Interannual Oscillations of Arctic Summertime TOA Fluxes

Arctic albedo in the summer months (June-August) is subject to large year-to-year variability from the regional warming, as perennial sea ice and snow cover continue to decrease. In this paper we report coherent interannual oscillatory features of the summer Arctic and subarctic top-of-atmosphere (TOA) fluxes from by Clouds and the Earth’s Radiant Energy System (CERES) since 2000. The monthly CERES TOA flux data are analysed by simply removing the multi-year means, to highlight their fluctuations as a function of time and latitude. The summer fluxes oscillate strongly with a period of ~4 years since 2009 with clear equatorward progression at 60°N-85°N latitudes. The interannual oscillations in the summer total TOA flux are dominated by the shortwave (SW) flux, consistent independent albedo observations from the Multiangle Imaging SprectroRadiometer (MISR) instrument. The SW and total TOA flux time series are further decomposed into poleward and equatorward components, in which the equatorward component contributes approximately two third of the variance. A further empirical orthogonal function (EOF) analysis identifies two Arctic regions, Beaufort Sea and Queen Elizabeth Islands (BS-QEI) and the Barents-Kara Sea (BKS), which are strongly associated with the observed interannual oscillations due to vulnerability in spring snow cover and summer sea ice extent. The excessive and deficient Arctic TOA energy fluctuations have profound impacts on mid-latitude weather and climate at intra-seasonal and interannual scales.