Reconstruction of the 1979–2006 Greenland ice sheet surface mass balance using the regional climate model MAR

Abstract

Abstract.Results from a 28-year simulation over the Greenland ice sheet (GrIS) reveal an increase of solid precipitation (+0.4±2.5 km 3 yr −2 ) and runoff (+7.9±3.3 km 3 yr −2 ) of surface meltwater. The net effect of these competing factors is a significant Surface Mass Balance (SMB) loss of −7.2±5.1 km 3 yr −2 . The contribution of changes in the net water vapour flux (+0.02±0.09 km 3 yr −2 ) and rainfall (+0.2±0.2 km 3 yr −2 ) to the SMB variability is negligible. The meltwater supply has increased because the GrIS surface has been warming up +2.4 • C since 1979. Sensible heat flux, latent heat flux and net solar radiation have not varied significantly over the last three decades. However, the simulated downward infrared flux has increased by 9.3 W m −2 since 1979. The natural climate variability (e.g. the North Atlantic Oscillation) does not explain these changes. The recent global warming, due to the greenhouse gas concentration increase induced by human activities, could be a cause of these changes. The doubling of surface meltwater flux into the ocean over the period suggests that the overall ice sheet mass balance has been increasingly negative, given the likely meltwater-induced acceleration of outlet glaciers. This study suggests that increased melting overshadows over an increased accumulation in a warming scenario and that the GrIS is likely to keep losing mass in the future. An enduring GrIS melting will probably affect in the future an certain effect on the stability of the thermohaline circulation and the global sea level rise.

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

“…Summer temperatures compare especially well around the coast and margin of the ice sheet, where temperature is most important for diagnosing melt. (Box et al, 2006), MAR (Fettweis, 2007) and RACMO2/GR (Ettema et al, 2009 Figure 4 shows annual accumulation and total precipitation patterns simulated by REMBO, as well as the most recent estimates obtained from station data and several ice core samples, compiled by Bales et al (2009). The simulated fields agree reasonably well with observations in large-scale patterns, despite local discrepancies.…”

“…The use of high-resolution, regional models driven by GCMs could additionally improve the representation of climate change over Greenland (Box et al, 2006;Fettweis, 2007;Ettema et al, 2009). However, for longer time scales, coupled GCMs are not only computationally expensive, but gradual changes in the topography and ice sheet extent should also be taken into account.…”

Temperature and Wind Climate of the Antarctic Peninsula as Simulated by a High-Resolution Regional Atmospheric Climate Model

“…Dynamical downscaling using high-resolution regional atmospheric climate models (RCMs) has proven to be a good method to represent climate at 5-10-km resolution. Moreover, RCMs can be specifically adapted to simulate the climate and surface mass balance of glaciated regions, such as the Antarctic ice sheet (Lenaerts et al 2012c;Van Wessem et al 2014b), but also of smaller partly glaciated regions, such as Greenland (Fettweis 2007;Ettema et al 2010), Patagonia (Lenaerts et al 2014), and Svalbard (Claremar et al 2012;Lang et al 2015).…”

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

“…[21] There are two main categories of SMB model that have been used to date; positive degree day (PDD) [Reeh, 1991] and energy balance (EB) models [Bougamont et al, 2005;Box et al, 2004;Fettweis, 2007;Greuell and Konzelmann, 1994]. PDD schemes are highly parameterized and computationally efficient, but they are tuned to present-day climatic conditions and so future projections can be called into question.…”