Greenland Surface Mass Balance as Simulated by the Community Earth System Model. Part I: Model Evaluation and 1850–2005 Results

Abstract

This study presents the first twenty-first-century projections of surface mass balance (SMB) changes for the Greenland Ice Sheet (GIS) with the Community Earth System Model (CESM), which includes a new ice sheet component. For glaciated surfaces, CESM includes a sophisticated calculation of energy fluxes, surface albedo, and snowpack hydrology (melt, percolation, refreezing, etc.). To efficiently resolve the high SMB gradients at the ice sheet margins and provide surface forcing at the scale needed by ice sheet models, the SMB is calculated at multiple elevations and interpolated to a finer 5-km ice sheet grid. During a twenty-firstcentury simulation driven by representative concentration pathway 8.5 (RCP8.5) forcing, the SMB decreases from 372 6 100 Gt yr 21 in 1980-99 to 278 6 143 Gt yr 21 in 2080-99. The 2080-99 near-surface temperatures over the GIS increase by 4.7 K (annual mean) with respect to 1980-99, only 1.3 times the global increase (13.7 K). Snowfall increases by 18%, while surface melt doubles. The ablation area increases from 9% of the GIS in 1980-99 to 28% in 2080-99. Over the ablation areas, summer downward longwave radiation and turbulent fluxes increase, while incoming shortwave radiation decreases owing to increased cloud cover. The reduction in GIS-averaged July albedo from 0.78 in 1980-99 to 0.75 in 2080-99 increases the absorbed solar radiation in this month by 12%. Summer warming is strongest in the north and east of Greenland owing to reduced sea ice cover. In the ablation area, summer temperature increases are smaller due to frequent periods of surface melt.

Corrigendum to "Dependence of Eemian Greenland temperature reconstructions on the ice sheet topography" published in Clim. Past, 10, 1221–1238, 2014

“…Qualitatively, Fig. 9f remains the same, but the values on the y axis have been changed and now correspond more closely to simulated albedo values shown in previous studies (e.g., Vizcaino et al, 2013). Moreover, in Sect.…”

Coupled ice sheet–climate modeling under glacial and pre-industrial boundary conditions

“…One way to obtain this and keep the models consistent would be to run an energy balance model on different height levels in the GCM and force the ISM with the modeled surface mass balance (Vizcaíno et al, 2013). We do not change the energy balance of the surface scheme of the atmosphere model and therefore do not introduce any www.clim-past.net/10/1817/2014/ new energy sources or sinks.…”

Modelling the climate and surface mass balance of polar ice sheets using RACMO2 – Part 1: Greenland (1958–2016)

“…positive degree day (PDD) models forced by statistically downscaled re-analyses (Hanna et al, 2011;Wilton et al, 2016), mass balance models forced by the climatological output of an RCM (HIRHAM4) (Mernild et al, 2010(Mernild et al, , 2011 and reconstruction of SMB obtained by combining RCM outputs with temperature and ice core accumulation measurements . In addition, Vizcaíno et al (2013) and Cullather et al (2014) respectively used the Community Earth System Model (CESM) at 1 • resolution (∼ 100 km) and the Goddard Earth Observing System model version 5 (GEOS-5) at 0.5 • resolution (∼ 50 km) to estimate recent and future mass losses of the GrIS.…”