A new, high‐resolution digital elevation model of Greenland fully validated with airborne laser altimeter data

Bamber, Jonathan; Ekholm, Simon; Krabill, William B.

doi:10.1029/2000jb900365

Cited by 199 publications

(195 citation statements)

References 27 publications

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“…The implications of feedback effects become more important as the length of simulation increases. A fixed ice sheet topography according to the digital elevation model (DEM) of Bamber et al [2001a] is also implemented in the simulations. This assumption is common in SMB modeling as compensating effects on SMB induced ice elevation and dynamic flow approximately cancel over short time periods [Huybrechts and de Wolde, 1999].…”

Section: Simulationmentioning

confidence: 99%

Exploration of parametric uncertainty in a surface mass balance model applied to the Greenland ice sheet

et al. 2012

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[1] Computational modeling of Earth system processes often requires simplifying assumptions of the real system. These necessary assumptions result in the definition of internal model parameters that can take a number of different values but must be explicitly defined for any one model simulation. The main issue with such an uncertain multidimensional input space is that many simulations are needed to adequately explore it. This study presents a generalized parameter screening experiment for use in future earth system modeling. This approach identifies model parameters that dominate uncertainty, therefore reducing to a manageable number the simulations required to explore the input space. The approach we adopt is relatively inexpensive to implement and can be applied at both the aggregate and disaggregate (e.g., regional) level. To demonstrate the potential of such a method, it is applied to a surface mass balance model of intermediate complexity over the Greenland ice sheet. All identified parameters were related to the surface melt parameterization, with albedo parameters being identified as the most important. Spatial distributions of the parameter sensitivities show that, in recent years, most parameter sensitivities are concentrated around the southwest and northern ice sheet margins. Simulations for the 21st century indicate an increase in sensitivity in these high melt areas especially in the northeast. Melt contributions from temperature and radiative effects are shown to be important on the order of parameters identified, and as a consequence, sensitivities are dependent on the present climate used for modeling surface mass balance.Citation: Fitzgerald, P. W., J. L. Bamber, J. K. Ridley, and J. C. Rougier (2012), Exploration of parametric uncertainty in a surface mass balance model applied to the Greenland ice sheet,

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Section: Simulationmentioning

confidence: 99%

Exploration of parametric uncertainty in a surface mass balance model applied to the Greenland ice sheet

et al. 2012

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“…The AWS are also equipped with Kipp & Zonen (K&Z) CNR1 net radiometers, results of which were reported in Van Figure 1. MODIS scene of west Greenland (August 23, 2006) with AWS locations (white dots) and ice sheet elevation contours (dashed lines, height interval 250 m, from Bamber et al, 2001). This figure is available in colour online at www.interscience.wiley.com/ijoc den .…”

Section: Automatic Weather Stationsmentioning

confidence: 99%

“…With a potential sea level rise of 7 m, the Greenland ice sheet (GrIS) is the largest source of fresh water in the Northern Hemisphere (Bamber et al, 2001). Recent observations suggest that the GrIS is significantly contributing to ongoing sea level rise (Cazenave, 2006;Lemke et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Surface layer climate and turbulent exchange in the ablation zone of the west Greenland ice sheet

Broeke

Smeets

Ettema

2008

Intl Journal of Climatology

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ABSTRACT:A comprehensive description is presented of the surface layer (SL) wind, temperature and humidity climate and the resulting sensible and latent heat exchange in the ablation zone of the west Greenland ice sheet. Over a four-year period (August 2003-August 2007, data were collected using three automatic weather stations (AWS) located along the 67°N latitude circle at 6, 38 and 88 km from the ice sheet margin at elevations of 490, 1020 and 1520 m asl. In the lower ablation zone, surface momentum roughness peaks in summer, which enhances the mechanical generation of turbulence in the stable SL. The SL is stably stratified throughout the year: in summer, the surface temperature is maximised at the melting point and therefore remains colder than the overlying air, in winter the surface is cooled by a radiation deficit. The resulting downward directed sensible heat flux cools the SL air. Humidity gradients between surface and air are small in winter, in response to low temperatures, but peak in spring, when the surface is not yet melting and can freely increase its temperature. This is especially true for the lower ablation zone, where winter accumulation is small so that the dark ice surface is already exposed at the onset of spring, allowing significant convection and sublimation. During summer, when the surface is melting, the sensible heat flux becomes directed towards the surface and sublimation changes into deposition in the lower ablation zone. The SL wind climate is dominated by katabatic forcing, with high directional constancy in summer and winter. The katabatic forcing is important to maintain turbulent exchange in the stable Greenland SL.

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“…For diagnostic simulations of the present-day climatology and surface mass balance of the GIS, we used the 5 km resolution gridded topography from Bamber et al (2001), aggregated to the resolution of the ice sheet model (20 km). Temperature and accumulation fields obtained from REMBO for the present-day Greenland topography have been compared to best estimates from observational data sets (correcting for elevation differences via the free atmospheric lapse rate).…”

Section: Simulations Of Climatology and Surface Mass Balance With Fixmentioning

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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A new, high‐resolution digital elevation model of Greenland fully validated with airborne laser altimeter data

Cited by 199 publications

References 27 publications

Exploration of parametric uncertainty in a surface mass balance model applied to the Greenland ice sheet

Exploration of parametric uncertainty in a surface mass balance model applied to the Greenland ice sheet

Surface layer climate and turbulent exchange in the ablation zone of the west 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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