Ocean-induced Melt Triggers Glacier Retreat in Northwest Greenland
[11-Jul-2018] In recent decades, tidewater glaciers in Northwest Greenland have contributed significantly to sea level rise but have also exhibited a complex spatial pattern of retreat that remained unexplained. In this new study, NASA's Oceans Melting Greenland (OMG) data are used in combination with ECCO model outputs to assess the role of the ocean in triggering the retreat of these glaciers.
The timing of glacier retreat coincides with the timing of increased ocean-induced melting of the ice faces above average, which is driven by increases in ocean temperature and surface melt. While glacier retreat is initiated by the ocean, the calving of icebergs remains the dominant process of mass loss at the ice fronts (71%). The speed of retreat varies strongly with the slope of the glacier bed: fast retreats occur in deep fjords exposed to warm water and slow retreats in shallow fjords with cold water. These results highlight the dominant role of ice-ocean interactions on the mass balance of the Greenland ice sheet.