Surface morphology and backscattering of ice-ridge sails in the Baltic Sea

• Published in: Journal of Glaciology
• Main Author: Manninen, A. T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1996
• Subjects: Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/s0022143000030604; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000030604

Abstract The triangular shape of an ice-ridge sail in the Baltic Sea was studied statistically. The dimensions and orientation of individual ice blocks were measured in several ridges. All measurements were carried out from the standpoint of backscattering research. The results confirm that given geometrical properties of the two sides of ice ridges are in general not equal. A slight negative correlation was found between the slope angle and width of the sail. All three orientations and all three size parameters of ice blocks on both sides of the ridges studied can be considered as normally distributed. A log-normal distribution, however, fits slightly better the dimensions of the orientationally best rectangular approximations of the polygonal main facets of flat ice blocks. Three-dimensional modelling of ice ridges is essential, since the total side-facet area visible is typically at least as large as the total main-facet area. Calculated incidence-angle distrubutions show that the broad distributions of orientations and dimensions make different redges appear very similar on radar images.