Surface mass balance of the Greenland icesheet in the regional climate model HIRHAM5: Present state and future prospects

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Ruth Mottram, Fredrik Boberg, Peter Langen, Shuting Yang, Christian Rodehacke, Jens Hesselbjerg Christensen, Marianne Sloth Madsen

Surface mass balance (SMB) is the builder of the Greenland ice sheet and the driver of ice dynamics. Quantifying the past, present and future state of SMB is important to understand the drivers and climatic processes that control SMB, and to both initialize and run ice sheet models which will help clarify sea level rise, and how likely changes in ice sheet extent feedback within the climate system. Regional climate models (RCMs) and climate reanalysis are used to quantify SMB estimates. Although different models have different spatial and temporal biases and may include different processes giving significant uncertainty in both SMB and the ice sheet dynamic response to it, all RCMs show a recent declining trend in SMB from the Greenland ice sheet, driven primarily by enhanced melt rates. Here, we present new simulations of the Greenland ice sheet SMB at 5 km resolution from the RCM HIRHAM5. The RCM is driven by the ERA-Interim reanalysis and the global climate model (GCM) EC-Earth v2.3 to make future projections for climate scenarios RCP8.5 and RCP4.5. Future estimates of SMB are affected by biases in driving global climate models, and feedbacks between the ice sheet surface and the global and regional climate system are neglected, likely resulting in significant underestimates of melt and precipitation over the ice sheet. These challenges will need to be met to better estimate the role climate change will have in modulating the surface mass balance of the Greenland ice sheet.
OriginalsprogDansk
TidsskriftLow Temperature Science. Series A. Physical Science
Vol/bind75
Sider (fra-til)105-115
Antal sider10
ISSN0439-3538
DOI
StatusUdgivet - 2017
Eksternt udgivetJa

    Forskningsområder

  • Greenland ice sheet surface mass balance climate climate modelling ice sheet modelling

ID: 186947335