Relating Atmospheric Circulation Patterns to Intense Surface Melt Periods along Coastal West Greenland

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Wednesday, 5 February 2014
Hall C3 (The Georgia World Congress Center )
Nathan Amador, Bucknell University, Lewisburg, PA; and A. M. Carleton

Supraglacial melt lakes have been found to be an important component to ice sheet hydrology as they have the propensity to drain large amounts (4.4 x 107 m3) of water in a short amount of time (~2 hours), and with little predictability. Melt lake drainage events (hydrofracturing) triggers an increase in velocity at nearby outlet glaciers by lubrication at the ice-bedrock interface (Zwally Effect); this process further enhances the ice sheet's contribution to sea level rise. We seek to better understand the controls on melt lake growth by analyzing synoptic-scale atmospheric circulation (via Synoptic indexing) over western Greenland during the peak time of the ablation season (late June) during the 2000-2012 summers. We identify a relationship between the North Atlantic Oscillation (NAO) and melt lake areas, in that summers with highly negative NAO values (NAO-) correlate with high melt years. We suggest two mechanisms responsible for anomalous melt patterns in the ablation (or melt) zone in coastal west Greenland: 1) Melting resulting from in-situ solar radiative forcing and 2) Advection of relatively Warm Maritime Air (from the North Atlantic).