Abstract :
A numerical 1-dimensional fine grid sea ice thermodynamic model is constructed accounting
specially for: (1) slush formation via flooding and percolation of rain- and snow meltwater,
(2) the consequent snow ice formation via slush freezing, and (3) the effects of snow compaction
on heat diffusion in snow cover. The model simulations from ice winter period 1979–90 are
viewed against corresponding observations at the Kemi fast ice station (65°39.8¾N, 24°31.4¾E).
The 11-year averaged model results show good overall consistency with corresponding total
ice thickness observations. The model slightly overestimates the snow ice thickness and underestimates
the snow thickness in February and March, which is mainly addressed to the model
assumption of isostatic balance (i.e., slush formation via flooding), which was probably not
fully satisfied at the coastal Kemi fast ice station. Supposing that this assumption is nevertheless
generally valid away from the very coastal fast ice zone, an estimate for sea ice sensitivity to
changes in winter precipitation rate is produced. Increased precipitation leads to an increase
only in snow ice thickness with little change in total ice thickness, while a reduction in precipitation
of more than −50% causes a significant increase in total ice thickness. The difference in
modeled total ice thickness for the case of artificially neglecting snow ice physics is about 25%,
which indicates the importance of including snow ice physics in a sea ice model dealing with
the seasonal sea ice zone
