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Steep Glacier Bed Knickpoints Mitigate Inland Thinning in Greenland
Author(s) -
Felikson Denis,
Catania Ginny,
Bartholomaus Timothy C.,
Morlighem Mathieu,
Noël Brice P. Y.
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl090112
Subject(s) - geology , thinning , glacier , glacier ice accumulation , glacier morphology , ice stream , greenland ice sheet , ice sheet , geomorphology , glacier terminus , tidewater glacier cycle , glacier mass balance , surge , rock glacier , oceanography , physical geography , cryosphere , sea ice , geography , ice calving , pregnancy , lactation , biology , genetics , forestry
Greenland’s outlet glaciers have been a leading source of mass loss and accompanying sea‐level rise from the Greenland Ice Sheet (GrIS) over the last 25 years. The dynamic component of outlet glacier mass loss depends on both the ice flux through the terminus and the inland extent of glacier thinning, initiated at the ice‐ocean interface. Here, we find limits to the inland spread of thinning that initiates at glacier termini for 141 ocean‐terminating outlet glaciers around the GrIS. Inland diffusion of thinning is limited by steep reaches of bed topography that we call “knickpoints.” We show that knickpoints exist beneath the majority of outlet glaciers but they are less steep in regions of gentle bed topography, giving glaciers in gentle bed topography the potential to contribute to ongoing and future mass loss from the GrIS by allowing the diffusion of thinning far into the ice sheet interior.