Active Layer Thermal Regime 1991–1996 at Qeqertarsuaq, Disko Island, Central West Greenland

Abstract

Air, ground surface, and active layer temperatures, and wind and net radiation measurements were obtained at 30-min intervals from 1991 through 1996 at 16 m a.s.l., near Qeqertarsuaq (69°15′N, 53°34′W) in Central West Greenland. Snow depth measurements were made on a daily basis. The mean annual air temperature was −5.1°C during the observation period. The typical maximum thickness of the active layer (sandy sediments) was about 175 to 180 cm and is typically attained in late September. Freezing of the active layer commences early October or late September. Below-freezing conditions typically prevails in the entire active layer from late-December or early January. Warming of the active layer in spring is rapid and usually occurs in early June or late May. This event is at least partly the result of infiltration of surface meltwater. In general, air temperature represents the major control on active layer temperatures at Qeqertarsuaq. Other important controls are exercised by wind speed and snow-cover thickness.