Abstract:
As most glaciers in southern Chile, the Mocho-Choshuenco ice cap has experienced large mass losses during the last decades. The projected global warming during the21st century gives reason to expect a further decreasing surface mass balance. In orderto estimate the consequences exerted by temperature enhancement on the dynamic be-haviour of the ice cap, the ice sheet model SICOPOLIS is applied to the ice cap. Todate, the Mocho-Choshuenco ice cap is by far the smallest cryospheric object analysedwith SICOPOLIS. First, the equations of the shallow ice approximation which are in-corporated by the model are derived from the basic principles of mass and momentumbalance. Then, a new surface mass balance parametrisation accounting for local differ-ences in the equilibrium line altitude due to wind deposition and solar radiation effectsis introduced and tested. Afterwards, the relevance of sliding on ice flow of the ice cap isanalysed. Finally, the ice cap is modelled up to the year 2065 under the increasing tem-peratures of the RCP2.6 and RCP8.5 scenarios. The shallow ice approximation provesto work well on the plateau of the ice cap, but shows difficulties at locations with higherslopes. The new surface mass balance parametrisation is able to improve the simulationof the ice extent, while sliding improves the ice thickness and velocity reproduction ofthe observed ice cap. However, the total ice volume is higher in the model than in reality.The future scenarios predict a strong decrease in ice mass: 47% and 74% of the ice capwould disappear until 2065 under the RCP2.6 and RCP8.5 scenarios, respectively. Thissuggests a possible complete disappearance of the ice cap until the end of the centuryunder the most pessimistic scenario.