It is possible to take into account the effects of ice coverage on the wave field. Ice covered sea is considered as ‘land’ assuming zero wave energy and boundary conditions at the ice edges are identical to boundary conditions at shorelines.
Mesh points are taken out of the calculations if the ice concentration (defined as the fraction of sea covered with ice) becomes larger than a user-defined concentration (default 0.33). If the ice concentration drops below this value, the corresponding mesh point is ‘re-activated’. The spectrum is then initialised with a PM spectrum based on a local wind direction with a peak frequency corresponding to the second highest discrete frequency.
The treatment of ice coverage follows the discontinuous approach described in e.g. Tolman (2003).
Maps of ice concentration are issued by e.g. meteorological institutes.