The Impact of Bare Ice Duration and Geo-Topographical Factors on the Darkening of the Greenland Ice Sheet

Abstract

Dark (low albedo) surface ice on the Greenland Ice Sheet enhances melting and subsequent runoff, a major mass loss contributor during the ablation season. The accumulation of both biological (e.g., glacier ice algae) and abiotic (e.g., mineral dust) light-absorbing particulates are important darkening factors, that are potentially influenced by the duration of snow-free, bare ice (a phenological factor), and other geo-topographical factors such as elevation, slope, aspect and the distance from the ice margin. Here, we present the first medium-resolution (30 m) analysis of the phenological and geo-topographical controls on the distribution of dark ice in SE and SW Greenland from statistical analysis of data derived from a harmonized satellite albedo product and ArcticDEM. The duration of bare ice primarily controls the distribution of dark surface ice, allowing for algae growth on inland ice surfaces in particular, whereas geo-topographical factors are only secondary controls.