Abstract

Measurements of the shape of the sea ice underside by submarine and other methods have enabled us to determine the statistical distributions which described under-ice morphology. Two of the most interesting findings are that (a) the probability density function of deep ice draft
and of the drafts of individual pressure ridges both obey a negative exponential distribution, and (b) the distribution of the spacings between successive pressure ridge keels obey a log-normal distribution. Agreement with the equations is very close. Other parameters of the ice underside, including fractal properties, are much more variable, as are characteristics such as the slop angles of pressure ridges. We examine to what extent the topography of the upper ice surface (freeboard instead of draft; sails instead of keels) obeys the same relationships, and speculate on the physical reasons for these distributions.