Ice-sheet contributions to future sea-level change

Gregory, Jonathan M.; Huybrechts, Philippe

doi:10.1098/rsta.2006.1796

Cited by 199 publications

(224 citation statements)

References 33 publications

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“…To determine future SMB changes, Gregory and Huybrechts (2006) combined annual time-series of temperature and precipitation simulated by low resolution AOGCM's, with spatial and seasonal patterns simulated by 4 high-resolution Atmosphere General Circulation Models (AGCM). This results in empirical relations of the form…”

Section: Antarctic and Greenland Ice Sheetmentioning

confidence: 99%

Towards regional projections of twenty-first century sea-level change based on IPCC SRES scenarios

et al. 2011

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Sea-level change is often considered to be globally uniform in sea-level projections. However, local relative sea-level (RSL) change can deviate substantially from the global mean. Here, we present maps of twenty-first century local RSL change estimates based on an ensemble of coupled climate model simulations for three emission scenarios. In the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4), the same model simulations were used for their projections of global mean sea-level rise. The contribution of the small glaciers and ice caps to local RSL change is calculated with a glacier model, based on a volume-area approach. The contributions of the Greenland and Antarctic ice sheets are obtained from IPCC AR4 estimates. The RSL distribution resulting from the land ice mass changes is then calculated by solving the sea-level equation for a rotating, elastic Earth model. Next, we add the pattern of steric RSL changes obtained from the coupled climate models and a model estimate for the effect of Glacial Isostatic Adjustment. The resulting ensemble mean RSL pattern reveals that many regions will experience RSL changes that differ substantially from the global mean. For the A1B ensemble, local RSL change values range from -3.91 to 0.79 m, with a global mean of 0.47 m. Although the RSL amplitude differs, the spatial patterns are similar for all three emission scenarios. The spread in the projections is dominated by the distribution of the steric contribution, at least for the processes included in this study. Extreme ice loss scenarios may alter this picture. For individual sites, we find a standard deviation for the combined contributions of approximately 10 cm, regardless of emission scenario.

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Section: Antarctic and Greenland Ice Sheetmentioning

confidence: 99%

Towards regional projections of twenty-first century sea-level change based on IPCC SRES scenarios

et al. 2011

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“…GrIS SMB has been estimated through the statistical downscaling of low resolution re-analysis data Hanna et al ( , 2005Hanna et al ( , 2002, and low resolution global climate model data (Huybrechts et al, 2004;Gregory and Huybrechts, 2006) through regional climate models (Box et al, 2004Ettema et al, 2010a, b;Fettweis, 2007;Fettweis et al, 2008;Lucas-Picher et al, 2012) and also through the interpolation of in situ observations from ice cores, snow pits, stake measurements and automatic weather stations ; however, these measurements are limited in both spatial and temporal coverage and are unable to separate components of SMB. The release of high-quality and consistent historical weather reanalysis data has made possible the modelling of the processes controlling SMB over the whole ice sheet.…”

Section: Introductionmentioning

confidence: 99%

Surface mass balance model intercomparison for the Greenland ice sheet

et al. 2013

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Abstract. A number of high resolution reconstructions of the surface mass balance (SMB) of the Greenland ice sheet (GrIS) have been produced using global re-analyses data extending back to 1958. These reconstructions have been used in a variety of applications but little is known about their consistency with each other and the impact of the downscaling method on the result. Here, we compare four reconstructions for the period 1960-2008 to assess the consistency in regional, seasonal and integrated SMB components. Total SMB estimates for the GrIS are in agreement within 34 % of the four model average when a common ice sheet mask is used. When models' native land/ice/sea masks are used this spread increases to 57 %. Variation in the spread of components of SMB from their mean: runoff 42 % (29 % native masks), precipitation 20 % (24 % native masks), melt 38 % (74 % native masks), refreeze 83 % (142 % native masks) show, with the exception of refreeze, a similar level of agreement once a common mask is used. Previously noted differences in the models' estimates are partially explained by ice sheet mask differences. Regionally there is less agreement, suggesting spatially compensating errors improve the integrated estimates.Modelled SMB estimates are compared with in situ observations from the accumulation and ablation areas. Agreement is higher in the accumulation area than the ablation area suggesting relatively high uncertainty in the estimation of ablation processes. Since the mid-1990s each model estimates a decreasing annual SMB. A similar period of decreasing SMB is also estimated for the period 1960-1972. The earlier decrease is due to reduced precipitation with runoff remaining unchanged, however, the recent decrease is associated with increased precipitation, now more than compensated for by increased melt driven runoff. Additionally, in three of the four models the equilibrium line altitude has risen since the mid-1990s, reducing the accumulation area at a rate of approximately 60 000 km 2 per decade due to increased melting. Improving process representation requires further study but the use of a single accurate ice sheet mask is a logical way to reduce uncertainty among models.

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“…Robinson et al: The Greenland Ice Sheet response to climate change Most studies of the short-and long-term response of the GIS to global warming use a rather simple approach, in which a simulated temperature anomaly field or a constant temperature offset is added to the modern climatological temperatures and a simple correction for elevation change is employed (e.g., Greve, 2000;Huybrechts et al, 2004;Parizek and Alley, 2004;Gregory and Huybrechts, 2006). While such an approach is justified for short-term predictions, it becomes less applicable on longer time scales, when the GIS can change dramatically.…”

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confidence: 99%

An efficient regional energy-moisture balance model for simulation of the Greenland Ice Sheet response to climate change

2010

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Abstract. In order to explore the response of the Greenland ice sheet (GIS) to climate change on long (centennial to multi-millennial) time scales, a regional energy-moisture balance model has been developed. This model simulates seasonal variations of temperature and precipitation over Greenland and explicitly accounts for elevation and albedo feedbacks. From these fields, the annual mean surface temperature and surface mass balance can be determined and used to force an ice sheet model. The melt component of the surface mass balance is computed here using both a positive degree day approach and a more physically-based alternative that includes insolation and albedo explicitly. As a validation of the climate model, we first simulated temperature and precipitation over Greenland for the prescribed, present-day topography. Our simulated climatology compares well to observations and does not differ significantly from that of a simple parameterization used in many previous simulations. Furthermore, the calculated surface mass balance using both melt schemes falls within the range of recent regional climate model results. For a prescribed, ice-free state, the differences in simulated climatology between the regional energy-moisture balance model and the simple parameterization become significant, with our model showing much stronger summer warming. When coupled to a threedimensional ice sheet model and initialized with present-day conditions, the two melt schemes both allow realistic simulations of the present-day GIS.

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Ice-sheet contributions to future sea-level change

Cited by 199 publications

References 33 publications

Towards regional projections of twenty-first century sea-level change based on IPCC SRES scenarios

Towards regional projections of twenty-first century sea-level change based on IPCC SRES scenarios

Surface mass balance model intercomparison for the Greenland ice sheet

An efficient regional energy-moisture balance model for simulation of the Greenland Ice Sheet response to climate change

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