Articles | Volume 5, issue 4
The Cryosphere, 5, 809–819, 2011

Special issue: Ice2sea – estimating the future contribution of continental...

The Cryosphere, 5, 809–819, 2011

Research article 12 Oct 2011

Research article | 12 Oct 2011

An improved semi-empirical model for the densification of Antarctic firn

S. R. M. Ligtenberg, M. M. Helsen, and M. R. van den Broeke S. R. M. Ligtenberg et al.
  • Institute for Marine and Atmospheric research Utrecht (IMAU) P.O. Box 80000, 3508 TA Utrecht, The Netherlands

Abstract. A firn densification model is presented that simulates steady-state Antarctic firn density profiles, as well as the temporal evolution of firn density and surface height. The model uses an improved firn densification expression that is tuned to fit depth-density observations. Liquid water processes (meltwater percolation, retention and refreezing) are also included. Two applications are presented. First, the steady-state model version is used to simulate the strong spatial variability in firn layer thickness across the Antarctic ice sheet. Second, the time-dependent model is run for 3 Antarctic locations with different climate conditions. Surface height changes are caused by a combination of accumulation, melting and firn densification processes. On all 3 locations, an upward trend of the surface during autumn, winter and spring is present, while during summer there is a more rapid lowering of the surface. Accumulation and (if present) melt introduce large inter-annual variability in surface height trends, possibly hiding ice dynamical thickening and thinning.