Impact of spatial resolution on the modelling of the Greenland ice sheet surface mass balance between 1990–2010, using the regional climate model MAR

Abstract

Abstract. With the aim to force an ice dynamical model, the Greenland ice sheet (GrIS) surface mass balance (SMB) was modelled at different spatial resolutions (15-50 km) for the period 1990-2010, using the regional climate model MAR (Modèle Atmosphérique Régional) forced by the ERA-INTERIM reanalysis. This comparison revealed that (i) the inter-annual variability of the SMB components is consistent within the different spatial resolutions investigated, (ii) the MAR model simulates heavier precipitation on average over the GrIS with decreasing spatial resolution, and (iii) the SMB components (except precipitation) can be derived from a simulation at lower resolution with an "intelligent" interpolation. This interpolation can also be used to approximate the SMB components over another topography/ice sheet mask of the GrIS. These results are important for the forcing of an ice dynamical model needed to enable future projections of the GrIS contribution to sea level rise over the coming centuries.

On the importance of the albedo parameterization for the mass balance of the Greenland ice sheet in EC-Earth

“…3c). This is in broad agreement with results from Franco et al (2012), who did RCM experiments with MAR on a range of spatial resolutions. Ice-sheet-integrated snowfall of the EC-Earth reference run is 95 Gt yr −1 larger than snowfall from RACMO2 (Table 2), but uncertainty estimates based on the interannual variability from these fields are quite large.…”

Surface mass balance model intercomparison for the Greenland ice sheet

“…However, unlike the PMM5 model, MAR is not recalibrated or corrected against in situ data. This iteration of MAR has notably been used in studies by Box et al (2012), Reijmer et al (2012) and Franco et al (2012).…”

A daily, 1 km resolution data set of downscaled Greenland ice sheet surface mass balance (1958–2015)

“…However, the current spatial resolution of RCMs, typically 5-20 km, remains too coarse to accurately resolve glaciated areas in topographically complex regions such as small isolated ice caps and marginal outlet glaciers flowing into narrow fjords. In these regions, the relatively coarse elevation and land ice masks used in RCMs might result in runoff underestimation (Franco et al, 2012;Noël et al, 2015), hampering realistic regional SMB estimates. Performing higher resolution simulations to address these issues would require a substantial computational effort and is thus restricted to case studies of small regions and relatively short time periods.…”

“…Vertical gradients of climate parameters were iteratively calibrated to enable the mass balance model to generate a realistic melt distribution for the period 1980-2010, but the very high resolution restricted the analysis to a few regions. Franco et al (2012) statistically downscaled GrIS SMB by interpolating each component of the Modèle Atmosphérique Régional (MAR) from the original 25 km grid to a 15 km resolution. This method used local daily vertical gradients, except for precipitation, to correct for elevation differences between MAR and a down-sampled version of the 5 km DEM from Bamber et al (2001).…”