Mar 25, 2016

Bathymetry data reveal glaciers vulnerable to ice-ocean interaction in Uummannaq and Vaigat glacial fjords, west Greenland

by
E. Rignot, I. Fenty, Y. Xu, C. Cai, I. Velicogna, C. Ó Cofaigh, J. A. Dowdeswell, W. Weinrebe, G. Catania, D. Duncan
,
Geophysical Research Letters
  • States that marine-terminating glaciers play a critical role in controlling Greenland's ice sheet mass balance
  • States that such glaciers' frontal margins interact vigorously with the ocean, but our understanding of this interaction is limited, in part, by a lack of bathymetry data (which is the underwater equivalent to topography)
  • Presents a multibeam echo sounding survey of 14 glacial fjords in the Uummannaq and Vaigat fjords, west Greenland, which extends from the continental shelf to the glacier fronts
  • Data reveals valleys with shallow sills, overdeepenings (>1300 m) from glacial erosion, and seafloor depths 100–1000 m deeper than in existing charts
  • Detects—where fjords are deep enough—the pervasive presence of warm, salty Atlantic Water (AW) (>2.5°C) with high melt potential
  • Also finds numerous glaciers grounded on shallow (<200 m) sills, standing in cold (<1°C) waters in otherwise deep fjords, i.e., with reduced melt potential
  • States bathymetric observations extending to the glacier fronts are critical to understand the glacier evolution