Albedo, or surface reflectivity, of the late summer Arctic sea-ice zone is decreasing, reports a study published online this week in Nature Climate Change. Sea-ice albedo is an important source of variability in climate model forecasts of sea-ice extent, and therefore this work may be important in improving projections.
Aku Riihela and colleagues use a new satellite-derived data set of albedo to investigate surface changes in Arctic sea-ice over three decades, from 1982 to 2009. They study the summer months, May-August, for both open-water and sea-ice regions of the Arctic Ocean. Excluding the sea-ice zone in May, all albedo trends show a significant reduction, with the strongest negative trend in August. These decreases are due to the increasing loss of sea-ice in the summer, and can be explained by a combination of sea-ice concentration, surface air temperature and time from start of the summer melt. The team also notes that the remaining sea-ice in August has a reduced albedo.