On the importance of the albedo parameterization for the mass balance of the Greenland ice sheet in EC-Earth
| Autor: | Helsen, Michiel M., Van De Wal, Roderik S.W., Reerink, Thomas J., Bintanja, Richard, Madsen, Marianne S., Yang, Shuting, Li, Qiang, Zhang, Qiong, Sub Dynamics Meteorology, Marine and Atmospheric Research |
|---|---|
| Přispěvatelé: | Sub Dynamics Meteorology, Marine and Atmospheric Research, Isotope Research, Ocean Ecosystems |
| Rok vydání: | 2017 |
| Předmět: |
010504 meteorology & atmospheric sciences
Greenland ice sheet Ice-albedo feedback Forcing (mathematics) 010502 geochemistry & geophysics Atmospheric sciences 01 natural sciences VALIDATION WEST GREENLAND Glacier mass balance DARK REGION lcsh:Environmental sciences MELT 0105 earth and related environmental sciences Earth-Surface Processes Water Science and Technology lcsh:GE1-350 ABLATION ZONE geography geography.geographical_feature_category lcsh:QE1-996.5 Albedo Snow lcsh:Geology VARIABILITY CLIMATE MODEL MAR SNOW Climatology Environmental science ENERGY-BALANCE Ice sheet SYSTEM Ablation zone |
| Zdroj: | Cryosphere, 11(4), 1949-1965. COPERNICUS GESELLSCHAFT MBH Cryosphere, 11(4), 1949. Copernicus Publications The Cryosphere, Vol 11, Pp 1949-1965 (2017) |
| ISSN: | 1994-0424 1994-0416 |
| Popis: | The albedo of the surface of ice sheets changes as a function of time due to the effects of deposition of new snow, ageing of dry snow, bare ice exposure, melting and run-off. Currently, the calculation of the albedo of ice sheets is highly parameterized within the earth system model EC-Earth by taking a constant value for areas with thick perennial snow cover. This is an important reason why the surface mass balance (SMB) of the Greenland ice sheet (GrIS) is poorly resolved in the model. The purpose of this study is to improve the SMB forcing of the GrIS by evaluating different parameter settings within a snow albedo scheme. By allowing ice-sheet albedo to vary as a function of wet and dry conditions, the spatial distribution of albedo and melt rate improves. Nevertheless, the spatial distribution of SMB in EC-Earth is not significantly improved. As a reason for this, we identify omissions in the current snow albedo scheme, such as separate treatment of snow and ice and the effect of refreezing. The resulting SMB is downscaled from the lower-resolution global climate model topography to the higher-resolution ice-sheet topography of the GrIS, such that the influence of these different SMB climatologies on the long-term evolution of the GrIS is tested by ice-sheet model simulations. From these ice-sheet simulations we conclude that an albedo scheme with a short response time of decaying albedo during wet conditions performs best with respect to long-term simulated ice-sheet volume. This results in an optimized albedo parameterization that can be used in future EC-Earth simulations with an interactive ice-sheet component. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|