Wind-driven modulation of warm water supply to a proglacial fjord, Jorge Montt Glacier, Patagonia

Abstract

Projections of sea level rise due to ice loss from the land to the ocean have been hampered by a lack of understanding of the role the ocean is playing in glacier retreat, including the processes that contribute to the supply of warm water to the ice-ocean interface. Here shipboard, moored, and weather station data collected off Jorge Montt, a rapidly retreating glacier in Patagonia, are analyzed to understand the influence of wind forcing. During summer, synoptic-scale down-fjord wind events enhance an estuarine-like two-layer flow, increasing the inflow of oceanic deep water. During up-fjord wind events, the inflow of deep water is significantly reduced, and a three-layer exchange flow develops. Overall, along-fjord wind forcing is shown to modulate the inflow of warm water to the fjord by a factor of 2.5 The results sug- gest that local, channelized winds can be an important process modulating warm water supply and melting of tidewater glaciers.