Greenland ice sheet surface mass balance of glaciers

Guest post by NedThe Greenland ice sheet has a negative mass balance, meaning that it is losing ice (Velicogna 2009, Jiang 2010). This loss occurs because the gain of new ice (in the form of snowfall within the ice sheet's interior zone of accumulation) cannot keep up with the rapid loss of ice through melting and the discharge of ice by marine terminating outlet glaciers (van den Broeke 2009).

Antarctic glaciers terminate on land or in the sea, as floating ice shelves or grounded or floating outlet glaciers. The Antarctic Ice Sheet contains 25,400,000 km 3 of ice, which, if it melted, would be equivalent to a sea level rise of 58 m[1]. The ice sheet is over 4000 m thick in places, and in places,... Surface mass balance (averaged over the period 1989–2009) of the Antarctic ice sheets (left) and the Greenland Ice Sheet (right) from the regional climate model RACMO2.3p2 in kg m −2 yr-1 (van Wessem et al., 2018; Noël et al., 2018a). Elevation contour levels (dashed) are shown every 500 m.

Dec 16, 2015 · To estimate the mass-balance history of the Greenland Ice Sheet — the time course of differences between mass gained by snow accumulation and that lost by melting and calving of icebergs ... In Greenland, the contribution from surface melting and runoff is comparable to calving and basal melting at the fronts of marine terminating outlet glaciers. In recent years, increasingly negative surface mass balance dominated the mass loss from the Greenland ice sheet (Enderlin et al., 2014).

The surface mass balance was nearly negative in 1998 (26 km 3 yr −1), consistent with Hanna et al. (2002), suggesting a strong negative mass balance for the ice sheet as a whole, given that iceberg discharge and basal melting would represent relatively large negative mass budget terms, approximately 239 and 32 km 3 yr −1, respectively ... The surface mass balance of the glacier is the difference of accumulating snow on the ice sheet (its income) and snow and ice losses from melting and calving (its expenditures). The volume of the ice sheet is its asset. On an ice sheet, the main factor driving flow is simply the mass balance input in the accumulation zone. Glacier ice today stores about three-fourths of all the fresh water in the world. Glacier ice covers about 11 percent of the world’s land area and would cause a world sea-level rise of about 90 metres (300 feet) if all existing ice melted. Glaciers occur in all parts of the world and at almost all latitudes. We reconstruct the mass balance of the Greenland Ice Sheet using a comprehensive survey of thickness, surface elevation, veloc-ity, and surface mass balance (SMB) of 260 glaciers from 1972 to 2018. We calculate mass discharge, D, into the ocean directly for 107 glaciers (85% of D) and indirectly for 110 glaciers (15%) Bangladesh,... The contribution of the Greenland ice sheet SMB decrease to the sea level rise is currently evaluated to be 5-10 cm by 2100 (Gregoryand Huybrechts, 2006; Fettweis et al., Estimation of the Sea Level Rise by 2100 Resulting from Changes in the Surface Mass Balance of the Greenland Ice Sheet 25 www.intechopen.com Greenland Ice Sheet Surface Mass Budget: DMI The trajectories were very different last year and this year, but the final result was about the same. Lining the two graphs up side by side, you can see the more than one trillion tons of ice which Greenland’s surface has gained over the past two years.