Regional grid refinement in an Earth system model: impacts on the simulated Greenland surface mass balance

van Kampenhout, Leonardus; Rhoades, Alan M.; Herrington, Adam R.; Zarzycki, Colin M.; Lenaerts, Jan T. M.; Sacks, William J.; van den Broeke, Michiel R.

In this study, the resolution dependence of the simulated Greenland ice sheet surface mass balance (GrIS SMB) in the variable-resolution Community Earth System Model (VR-CESM) is investigated. Coupled atmosphere–land simulations are performed on two regionally refined grids over Greenland at 0.5 (∼55 km) and 0.25 (∼28 km), maintaining a quasi-uniform resolution of 1 (∼111 km) over the rest of the globe. On the refined grids, the SMB in the accumulation zone is significantly improved compared to airborne radar and in situ observations, with a general wetting (more snowfall) at the margins and a drying (less snowfall) in the interior GrIS. Total GrIS precipitation decreases with resolution, which is in line with best-available regional climate model results. In the ablation zone, CESM starts developing a positive SMB bias with increased resolution in some basins, notably in the east and the north. The mismatch in ablation is linked to changes in cloud cover in VR-CESM, and a reduced effectiveness of the elevation classes subgrid parametrization in CESM. Overall, our pilot study introduces VR-CESM as a new tool in the cryospheric sciences, which could be used to dynamically downscale SMB in scenario simulations and to force dynamical ice sheet models through the CESM coupling framework.

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Zitierform:

van Kampenhout, Leonardus / Rhoades, Alan M. / Herrington, Adam R. / et al: Regional grid refinement in an Earth system model: impacts on the simulated Greenland surface mass balance. 2019. Copernicus Publications.

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Rechteinhaber: Leonardus van Kampenhout et al.

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