Several models have been developed to simulate mass balance at the glacier surface, from empirical/statistical approaches using temperature only to physically-based approaches including all the energy fluxes at the glacier surface.
Empirical approaches are based on relations between monthly or annual precipitation and accumulation on one side, and temperature and ablation on the other side, to compute the glacier mass balance. Thus, the use of simple glacier MB models is often justified by their modest forcing needs. However, such empirical models are likely to miss important feedbacks related to the strong influence of the snow/ice albedo on glacier SMB (Sicart et al., 2008).
Physical approaches consider all energy exchanges between the glacier and the atmosphere and are able to represent snowmelt spatial and temporal variability, such as those related to albedo variations. Yet, such approaches require more atmospheric variables that are difficult to measure and simulate at the glacier.
In the IFROG project, a twin experience will be done by simulating the future change of glacier MB using, the physical snow model Crocus and a simpler degree day model to simulate the future changes of the three glaciers by 2100. The comparison of these two approaches will provide valuable clues for the choice of the model complexity to simulate future change of surface mass balance in a warming context.