Forskning ved Københavns Universitet - Københavns Universitet


Greenland ice sheet surface mass-balance modeling in a 131-Yr perspective, 1950-2080

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

Fluctuations in the Greenland ice sheet (GrIS) surface mass balance (SMB) and freshwater influx to the surrounding oceans closely follow climate fluctuations and are of considerable importance to the global eustatic sea level rise.Astate-of-the-art snow-evolution modeling system(SnowModel) was used to simulate variations in theGrISmelt extent, surfacewater balance components, changes inSMB, and freshwater influx to the ocean. The simulations are based on the Intergovernmental Panel on Climate Change scenario A1B modeled by the HIRHAM4 regional climate model (RCM) using boundary conditions from the ECHAM5 atmosphere-ocean general circulation model (AOGCM) from 1950 through 2080. In situ meteorological station [Greenland Climate Network (GC-Net) andWorld Meteorological Organization (WMO)DanishMeteorological Institute (DMI)] observations from inside and outside the GrIS were used to validate and correct RCM output data before they were used as input for SnowModel. Satellite observations and independent SMB studies were used to validate the SnowModel output and confirmthemodel's robustness. The authors simulated an ~90% increase in end-of-summer surface melt extent (0.483 × 106 km2) from 1950 to 2080 and a melt index (above 2000-m elevation) increase of 138% (1.96 × 106 km2 × days). The greatest difference in melt extent occurred in the southern part of theGrIS, and the greatest changes in the number of melt dayswere seen in the eastern part of the GrIS (~50%-70%) and were lowest in the west (~20%-30%). The rate of SMB loss, largely tied to changes in ablation processes, leads to an enhanced average loss of 331 km3 from 1950 to 2080 and an average SMB level of 299 km3 for the period 2070-80. GrIS surface freshwater runoff yielded a eustatic rise in sea level from 0.8±0.1 (1950-59) to 1.9±0.1 mm(2070-80) sea level equivalent (SLE) yr-1. The accumulated GrIS fresh water run off contribution from surface melting equaled 160-mm SLE from 1950 through 2080.

TidsskriftJournal of Hydrometeorology
Udgave nummer1
Sider (fra-til)3-25
Antal sider23
StatusUdgivet - 1 feb. 2010

ID: 186940874