TY - JOUR
T1 - On the recent contribution of the Greenland ice sheet to sea level change
AU - Van Den Broeke, Michiel R.
AU - Enderlin, Ellyn M.
AU - Howat, Ian M.
AU - Kuipers Munneke, Peter
AU - Noël, Brice P.Y.
AU - Jan Van De Berg, Willem
AU - Van Meijgaard, Erik
AU - Wouters, Bert
N1 - Publisher Copyright:
© Author(s) 2016.
PY - 2016/9/6
Y1 - 2016/9/6
N2 - We assess the recent contribution of the Greenland ice sheet (GrIS) to sea level change. We use the mass budget method, which quantifies ice sheet mass balance (MB) as the difference between surface mass balance (SMB) and solid ice discharge across the grounding line (D). A comparison with independent gravity change observations from GRACE shows good agreement for the overlapping period 2002-2015, giving confidence in the partitioning of recent GrIS mass changes. The estimated 1995 value of D and the 1958-1995 average value of SMB are similar at 411 and 418Gt yr-1, respectively, suggesting that ice flow in the mid-1990s was well adjusted to the average annual mass input, reminiscent of an ice sheet in approximate balance. Starting in the early to mid-1990s, SMB decreased while D increased, leading to quasi-persistent negative MB. About 60% of the associated mass loss since 1991 is caused by changes in SMB and the remainder by D. The decrease in SMB is fully driven by an increase in surface melt and subsequent meltwater runoff, which is slightly compensated by a small ( < 3%) increase in snowfall. The excess runoff originates from low-lying (< 2000ma.s.l.) parts of the ice sheet; higher up, increased refreezing prevents runoff of meltwater from occurring, at the expense of increased firn temperatures and depleted pore space. With a 1991-2015 average annual mass loss of ∼ 0.47±0.23mm sea level equivalent (SLE) and a peak contribution of 1.2mm SLE in 2012, the GrIS has recently become a major source of global mean sea level rise.
AB - We assess the recent contribution of the Greenland ice sheet (GrIS) to sea level change. We use the mass budget method, which quantifies ice sheet mass balance (MB) as the difference between surface mass balance (SMB) and solid ice discharge across the grounding line (D). A comparison with independent gravity change observations from GRACE shows good agreement for the overlapping period 2002-2015, giving confidence in the partitioning of recent GrIS mass changes. The estimated 1995 value of D and the 1958-1995 average value of SMB are similar at 411 and 418Gt yr-1, respectively, suggesting that ice flow in the mid-1990s was well adjusted to the average annual mass input, reminiscent of an ice sheet in approximate balance. Starting in the early to mid-1990s, SMB decreased while D increased, leading to quasi-persistent negative MB. About 60% of the associated mass loss since 1991 is caused by changes in SMB and the remainder by D. The decrease in SMB is fully driven by an increase in surface melt and subsequent meltwater runoff, which is slightly compensated by a small ( < 3%) increase in snowfall. The excess runoff originates from low-lying (< 2000ma.s.l.) parts of the ice sheet; higher up, increased refreezing prevents runoff of meltwater from occurring, at the expense of increased firn temperatures and depleted pore space. With a 1991-2015 average annual mass loss of ∼ 0.47±0.23mm sea level equivalent (SLE) and a peak contribution of 1.2mm SLE in 2012, the GrIS has recently become a major source of global mean sea level rise.
UR - http://www.scopus.com/inward/record.url?scp=84986294540&partnerID=8YFLogxK
U2 - 10.5194/tc-10-1933-2016
DO - 10.5194/tc-10-1933-2016
M3 - Article
AN - SCOPUS:84986294540
SN - 1994-0416
VL - 10
SP - 1933
EP - 1946
JO - Cryosphere
JF - Cryosphere
IS - 5
ER -