A three-dimensional climate/ ice-sheet model applied to the Last Glacial Maximum

• Main Authors: Huybrechts, Philippe, T'siobbel, S.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 1997
• Subjects: Annals of Glaciology; Ice Sheet; North Atlantic
• Online Access: https://epic.awi.de/id/eprint/1475/; https://epic.awi.de/id/eprint/1475/1/Huy1997b.pdf; https://hdl.handle.net/10013/epic.12066; https://hdl.handle.net/10013/epic.12066.d001

A quasi-three-dimensional climate model (Sellers, 1983) was used to simulate the climate of the Last Glacial Maximum in order to provide climatic input forthe modelling of the northern hemisphere ice sheets. The climate model is basically a coarse-gridded GCM with simplified dynamics, and was subject toappropriate boundary conditions for ice-sheet elevation, atmospheric CO2 concentration and orbital parameters. When compared with the present-daysimulation, the simulated climate at the Last Glacial Maximum is characterized by a global annual cooling of 3.5deg.C and a reduction in global annualprecipitation of 7.5%, which agrees well with results from other, more complex GCM's. Also the patterns of temperature change compare fairly with mostother GCM results, except for a smaller cooling over the North Atlantic and the larger cooling predicted for the summer rather than for the winter overEurasia. The climate model is able to simulate changes in northern hemisphere tropospheric circulation, yielding enhanced westerlies in the vicinity of theLaurentide and Eurasian ice sheets. However, the simulated precipitation patterns are less convincing, and show a distinct mean precipitation increase over theLaurentide ice sheet. Nevertheless, when using the mean-monthly fields of LGM minus present-day anomalies of temperature and precipitation rate to drive athree-dimensional thermomechanical ice-sheet model, it was demonstrated that within realistic bounds of the ice-flow and mass-balance parameters, veryreasonable reconstructions of the Last Glacial Maximum ice sheets could be obtained.