CPP-09. Observations of Seasonal Changes in the Arctic Energy Budget

Strong positive climate feedbacks in the Arctic cause surface temperatures to rise much faster than the global average and modify the top-of-atmosphere (TOA) energy budget. With the Arctic climate strongly controlled by annual cycles in solar insolation, sea ice extent, cloud properties, and meridional heat transport, seasonal trends observed at the TOA capture changes in climate processes active at different times of the year. Using nearly two decades of continuous observations of short- and longwave irradiance from the CERES and AIRS satellite missions, we investigate seasonal trends in the Arctic energy budget. We find statistically significant increases in broadband absorbed shortwave radiation during the boreal summer and fall, consistent with the observed decline in Arctic sea ice extent. Outgoing longwave radiation increases significantly in the fall but is nearly unchanged during the summer, reflecting the delayed emission of the shortwave energy resulting from sea ice melt and ocean uptake. Spectrally-resolved observations from AIRS show similar trends and help to identify the role of water vapor and other atmospheric absorbers in Arctic warming.