Author(s): Ole-Christian Ekeberg; Knut Hoyland; Edmond Hansen; Mark Tschudi
Linked Author(s): Knut Hoyland
Keywords: No Keywords
Abstract: The present study identified ice ridges from upward looking sonar data from the period 2006-2011in the Fram Strait. During this period there has been a decrease in the fraction of ice deeper than5 m. This is a reduction in the part of the ice which typically is deformed and thus the change is primarily within the ridged part of the ice population. Ridges were identified using the Rayleigh criterion with a threshold of 2.5 m and a minimum draft of 5 m. Both the number of ridges (-204 to-792 ridges/year) and the mean draft (-7.2 to-13.2 cm/year) decreased during the period2006-2011. We argue that an increasing fraction of first-year ridges-a result of the recent basin wide decrease in ice age-is an important contributing factor, through its greater sensitivity to melting/disintegration than old ridges.