Surface albedo is a fundamental climate parameter as it governs the amount of solar energy available for absorption by the surface of the earth. In the polar regions, the high albedo sea ice allow very little solar energy to be absorbed by the darker ocean. Open water absorbs between 85 and 95% of the incoming solar energy, whereas, only 30-50% is absorbed by sea ice. However, as the areal extent of sea ice continues to decrease, the heat input into the ocean increases. The increased absorption of energy from the sun further warms the water column, delaying autumn freeze-up and slowing ice growth. The recent pattern of significantly lower Arctic sea ice extent is consistent with the ice-albedo feedback in the Arctic system that enhances the link between warming and reduced ice. Explaining the rapid retreat of Arctic sea ice during the last few years requires understanding of all the relevant processes contributing to the loss of ice, including the ice-albedo feedback process. However, high-quality and consistent observations of Arctic sea ice are currently lacking. The recently released NRC report on �Toward an Integrated Arctic Observing Network� [NRC, 2006] identified Arctic sea ice albedo as a critical observational gap in our understanding of environmental change in the Arctic. This project will fill this observational gap and further our understanding of how the ice-albedo feedback process is influencing change in the Arctic by developing an algorithm to compute Arctic sea ice albedo from MODIS, with applicability to future sensors, such as the NPP/NPOESS VIIRS instrument. In order to be able to quantify and understand the rapid environmental changes currently taking place in the Arctic, it is essential that steps are taken now to fill observational gaps such as the gap in sea ice albedo.
