Abstract :
[en] The retreat and acceleration of Greenland glaciers since the mid-1990s have been attributed to the enhanced intrusion of warm Atlantic Waters (AW) into fjords, but this assertion has not been quantitatively tested on a Greenland-wide basis or included in models. Here, we investigate how AW influenced retreat at 226 marine-terminating glaciers using ocean modeling, remote sensing, and in situ observations. We identify 74 glaciers in deep fjords with AW controlling 49% of the mass loss that retreated when warming increased undercutting by 48%. Conversely, 27 glaciers calving on shallow ridges and 24 in cold, shallow waters retreated little, contributing 15% of the loss, while 10 glaciers retreated substantially following the collapse of several ice shelves. The retreat mechanisms remain undiagnosed at 87 glaciers without ocean and bathymetry data, which controlled 19% of the loss. Ice sheet projections that exclude ocean-induced undercutting may underestimate mass loss by at least a factor of 2.
Funding text :
This project was conducted at the University of California Irvine as part of NASA’s OMG Mission and at the Jet Propulsion Laboratory, California Institute of Technology under a contract from NASA. M.W. was supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, California Institute of Technology, administered by the Universities Space Research Association under contract with NASA. ECCO (281945.02.25.03.49) was supported by the NASA Physical Oceanography; Modelling, Analysis, and Prediction; and Cryosphere Programs. M.v.d.B. acknowledges support from the Netherlands Earth System Science Centre (NESSC). B.N. was funded by the Netherlands Organisation for Scientific Research (NWO) VENI grant VI.Veni.192.019. J.M. and R.M. acknowledge support from the French National Research Agency (ANR) grant (ANR-19-CE01-0011-01). M.M. was supported by the National Science Foundation’s ARCSS program (no. 1504230). J.K.W. acknowledges support from the NASA/JPL OMG (87-19754). Copyright: 2020. All rights reserved.
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