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Title: High resolution (1 km) positive degree-day modelling of Greenland ice sheet surface mass balance, 1870–2012 using reanalysis data

Here, we show results from a positive degree-day (PDD) model of Greenland ice sheet (GrIS) surface mass balance (SMB), 1870–2012, forced with reanalysis data. The model includes an improved daily temperature parameterization as compared with a previous version and is run at 1 km rather than 5 km resolution. The improvements lead overall to higher SMB with the same forcing data. We also compare our model with results from two regional climate models (RCMs). While there is good qualitative agreement between our PDD model and the RCMs, it usually results in lower precipitation and lower runoff but approximately equivalent SMB: mean 1979–2012 SMB (± standard deviation), in Gt a –1, is 382 ± 78 in the PDD model, compared with 379 ± 101 and 425 ± 90 for the RCMs. Comparison with in situ SMB observations suggests that the RCMs may be more accurate than PDD at local level, in some areas, although the latter generally compares well. Dividing the GrIS into seven drainage basins we show that SMB has decreased sharply in all regions since 2000. Finally we show correlation between runoff close to two calving glaciers and either calving front retreat or calving flux, this being most noticeablemore » from the mid-1990s.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4]
  1. Univ. of Sheffield, Sheffield (United Kingdom)
  2. Utrecht Univ., Utrecht (The Netherlands)
  3. Univ. of Liege, Liege (Belgium)
  4. Vrije Univ. Brussel, Brussels (Belgium)
Publication Date:
Grant/Contract Number:
SC0009988
Type:
Accepted Manuscript
Journal Name:
Journal of Glaciology
Additional Journal Information:
Journal Volume: 63; Journal Issue: 237; Journal ID: ISSN 0022-1430
Publisher:
International Glaciological Society
Research Org:
Univ. of Sheffield, Sheffield (United Kingdom)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; arctic glaciology; ice-sheet mass balance; bass-balance reconstruction
OSTI Identifier:
1358439