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Title: Reactivation of Kamb Ice Stream tributaries triggers century-scale reorganization of Siple Coast ice flow in West Antarctica

Ongoing, centennial-scale flow variability within the Ross ice streams of West Antarctica suggests that the present-day positive mass balance in this region may reverse in the future. Here we use a three-dimensional ice sheet model to simulate ice flow in this region over 250 years. The flow responds to changing basal properties, as a subglacial till layer interacts with water transported in an active subglacial hydrological system. We show that a persistent weak bed beneath the tributaries of the dormant Kamb Ice Stream is a source of internal ice flow instability, which reorganizes all ice streams in this region, leading to a reduced (positive) mass balance within decades and a net loss of ice within two centuries. This hitherto unaccounted for flow variability could raise sea level by 5 mm this century. Furthermore, better constraints on future sea level change from this region will require improved estimates of geothermal heat flux and subglacial water transport.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [3]
  1. Univ. of Cambridge, Cambridge (United Kingdom)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Univ. of California, San Diego, La Jolla, CA (United States)
  4. Univ. of California, Santa Cruz, CA (United States)
Publication Date:
OSTI Identifier:
1255085
Report Number(s):
LA-UR--15-27433
Journal ID: ISSN 0094-8276
Grant/Contract Number:
NE/E005950/1; NE/J005800/1; 0338295; ANT-0838885; AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 42; Journal Issue: 20; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 97 MATHEMATICS AND COMPUTING