Greenland climate simulations show high Eemian surface melt

• Main Authors: Plach, Andreas, Vinther, Bo M., Nisancioglu, Kerim H., Vudayagiri, Sindhu, Blunier, Thomas
• Format: Text
• Language: English
• Published: 2020
• Subjects: Greenland; Tac; Greenland ice core; GRIP; ice core
• Online Access: https://doi.org/10.5194/cp-2020-101; https://cp.copernicus.org/preprints/cp-2020-101/

This study presents simulations of Greenland surface melt for the Eemian interglacial period (~130000 to 115000 years ago) derived from regional climate simulations with a coupled surface energy balance model. Surface melt is of high relevance for ice core records because it can influence observations, e.g., lower the preserved total air content (TAC) used to infer past surface elevation. An investigation of surface melt is particularly interesting for warm periods, such as the Eemian interglacial period, with enhanced surface melt. Furthermore, Eemian ice is the deepest and most compressed ice preserved on Greenland, which means that melt layers can not be identified visually. Therefore, a knowledge of potential melt layers would be advantageous. The simulations presented here show Eemian surface melt at all deep Greenland ice core locations. Estimated TAC, based on simulated melt during the Eemian, could explain the lower TAC observations: at the summit of Greenland (GRIP) a refreezing ratio of more than 25 % of the annual accumulation is simulated. As a consequence, elevated levels of surface melt during warm periods should be considered when interpreting Greenland TAC measurements as surface elevation changes. Additionally to estimating the influence of melt on past TAC in ice cores, the simulated surface melt could also be used to identify potential coring locations where Greenland ice might be best preserved.