The areal ice distribution in a pack ice field is described using a number of classes, characterized by different ice thicknesses. Each class may have a snow layer on top and evolves according to the thermodynamic forcing (same for all classes) and is followed through time. Mechanical forcing leads to ice export and deformation. The ice export is quantified by the parameter e describing the areal export of ice per unit of time. The deformation is quantified by the parameter r describing the area of open water generated by deformation per unit of time. The fraction of summer heat absorbed in leads and utilized for ice melting is quantified by the parameter gop. The model is applied to the Arctic Ocean. It is run to a steady state for different combinations of e, r, and gop, and the response of the thickness distribution to these parameters may thereby be quantified. It is shown that the ice generally gets thinner for increasing export. The response to deformation is dependent on gop such that the mean thickness increases with r for small gop (i.e., no effect or just a small melting effect of the heat absorbed in leads) but decreases with r for large gop. The overall effect of gop is that the mean thickness decreases with increasing gop. For gop close to 1 and moderate values of e and r the ice sheet melts completely in the summer. ¿ American Geophysical Union 1992