A statistical analysis of Arctic pressure ridge morphology

Individual pressure ridges were identified on both sensors: the shape on the upward looking sonar was used to obtain draft and apparent slopes and width of each ridge, while the orientation of the ridge as revealed by the side scan sonar was used to convert these figures into absolute slopes and width. The data set comprises 729 ridges. It was found that in addition to ridge spacing, ridge drafts fit a lognormal distribution better than a negative exponential; that the mean draft of ridges diminishes with downstream distance in the Trans‐3Polar Drift Stream at about 0.625 m per degree, suggesting a faster melt rate for ridge bottoms than for the ice as a whole; and that ridge widths and slopes also fit lognormal distributions. An empirical relationship was found relating ridge slope to the ratio of half width to draft. The mean ridge slope varied with location but always lay in the range 21.7° to 26.5°.