Effects of glaciers on annual runoff east of Nuuk/Godthåb, West Greenland

Abstract

The Kangerluarsunnguaq basin east of Nuuk/Godthåb has only a slight glacier cover while glaciers contribute about 80 per cent of the total runoff from Isortuarsuup Tasia. The two basins have similar seasonal variations of runoff and very different year-to-year variation. For example, annual runoff from Kangerluarsunnguaq closely follows annual precipitation variations in Nuuk, confirming that the basin is essentially a precipitation basin. By contrast annual runoff from Isortuarsuup Tasia is in anti-phase to precipitation with a lower amplitude. This is an example of the 'glacier smoothing' effect whereby ablation variations tend to offset precipitation variations. However, runoff from Isortuarsuup Tasia is also influenced by ice-dammed lakes which absorb water for several years and then drain suddenly.