Author(s): Matti Lepparanta; John E. Lewis; Hardy B. Granberg
Linked Author(s): Matti Leppäranta
Keywords: No Keywords
Abstract: Results of helicopter-borne laser profiling of ice surface in the Baltic Sea in March 1988 are described. The laser was a PRAM III system with a measurement frequency of 1-4 kHz, a footprint 20 cm and a potential vertical resolution 2.0 cm. In this paper, the overall distributions of the size and spacing of ice ridges in the Bay of Bothnia are described. They are based on the total of 29 profiles of length 12 km. The profiles were divided into three groups representing different ice conditions. Ice ridges were identified using the Rayleigh criterion and a cutoff height of 50 cm. The ridge height was on average 65-71 cm with a maximum 198 cm. The number of ridges was 0.5-3.9 km-1. The distributions of the ridge height and spacing showed qualitative agreement with the exponential distribution; however, the occurrence of large ridges and spacings are underestimated with a universal exponential distribution.
Year: 1990