The Cryosphere Discuss., 8, 1151-1189, 2014
1Potsdam Institute for Climate Impact Research, Potsdam, Germany
2Universidad Complutense Madrid, 28040 Madrid, Spain
3Instituto de Geociencias, UCM-CSIC, 28040 Madrid, Spain
Abstract. In this paper, we propose a new sub-grid scale parameterization for the ice discharge into the ocean through outlet glaciers and inspect the role of different observational and palaeo constraints for the choice of an optimal set of model parameters. This parameterization was introduced into the polythermal ice-sheet model SICOPOLIS, which is coupled to the regional climate model of intermediate complexity REMBO. Using the coupled model, we performed large ensemble simulations over the last two glacial cycles. We exploit two major parameters: a melt parameter in the surface melt scheme of REMBO and an ice discharge parameter in our parameterization of ice discharge. Our constraints are the present-day Greenland ice sheet surface elevation, surface mass balance partition (ratio between ice discharge and total precipitation) and the Eemian interglacial elevation drop relative to present-day in the vicinity of the NEEM ice core. We show that the ice discharge parameterization enables us to simulate both the correct ice-sheet shape and mass balance partition at the same time without explicitly resolving the Greenland outlet glaciers. For model verification, we compare simulated total and sectoral ice discharge with those from other findings, including observations. For the model versions, which are inside the range of observational and palaeo constraints, our simulated Greenland ice sheet contribution to Eemian sea level rise relative to present-day amounts to 1.4 m on average (in the range of 0.6 and 2.5 m)
During the Hypsithermal, 5,000 years ago, when the Sahara still supported large animals, fish and humans. sea level was 2 meters (6 feet) higher than now.ReplyDelete
I have confirmed this by field work and so have many others.