Addressing a Gap in Our Understanding of the Polar Energy Balance with the Polar Radiant Energy in the Far Infrared Experiment (PREFIRE)

While the underlying processes governing polar surface energy and mass budgets are reasonably well known, current climate models still struggle to achieve consensus in their predicted rates of Arctic warming, sea ice decline, and ice sheet melt. This may be attributed at least in part, to a lack of observational constraints on fundamental quantities like spectral surface emissivity and the atmospheric greenhouse effect stemming from the challenges of making sustained, high quality atmospheric measurements in the inhospitable polar regions. This observing gap is evident in the large spreads in Arctic and Antarctic energy budget reconstructions derived from recent satellite and reanalysis. This spread, in turn, leads to large differences in both the magnitude and seasonality of the implied surface heat storage and heat transport into polar regions from lower latitudes that likely have substantial implications for predicting changes in sea ice cover, precipitation, ice sheet dynamics, and surface mass balance. The Polar Radiant Energy in the Far Infrared Experiment (PREFIRE) aims to reduce these uncertainties by filling a significant gap in our knowledge of the spatial and temporal variations of thermal energy exchanges in polar regions. PREFIRE plans to make spectrally-resolved measurements across most of the energetically-relevant portion of the infrared spectrum including wavelengths longer than 15 microns that account for up to 60% of all emission in polar regions yet have never been systematically observed from space. Estimates of spectral surface emissivity and the atmospheric greenhouse effect derived from these measurements would dramatically advance models of thermal fluxes in the mid- and high-latitudes.