Supraglacial lake spatial structure in western Greenland during the 2007 ablation season

Abstract

[1] Increases in surface melt rates along the Greenland ice sheet margin have accelerated meltwater production, resulting in supraglacial lakes that can drain rapidly and enhance basal sliding. In this study, supraglacial lakes in western Greenland are mapped from multitemporal Landsat panchromatic imagery during the 2007 melt season. The analysis models lake spatial structure and establishes sequencing of drainage from 6 June through 9 August 2007. Results indicate high spatial clustering at lower elevations (between ∼100 and 700 m), with minimum lake-to-lake distances of ∼100–500 m and lake sizes <0.5 km2. At higher elevations (700–1200 m), clustering decreases with minimum distances on the order of 900–1400 m and lake sizes between 0.5 and 1 km2. Lakes at elevations above 1200 m exhibit less clustering and smaller areas. Clustering was spatially heterogeneous within elevation bands, with high clustering between ice streams and fewer lakes along shear margins. Spatial patterns of lake drainage throughout the 2007 melt season exhibit strong spatial coherency. The magnitude of clustering reveals patterns caused by surface melt production and water routing through surface streams as well as in situ drainage. Cluster patterns are influenced by proximity to crevasses fields, shear margins, as well as topographic structure.