Decline of Arctic Sea-Ice Thickness as Evidenced by Submarine Measurements

• Activity Number: 630
• Type: Invited
• Date/Time: Thursday, August 2, 2012 : 10:30 AM to 12:20 PM
• Sponsor: ASA Advisory Committee on Climate Change Policy
• Author(s): Donald Bame Percival*+
• Companies: University of Washington
• Keywords: long-range dependence ; long-memory processes ; multiple regression ; space-time analysis ; climate change

Abstract

Starting in 1958, U.S. Navy submarines recorded the draft (93% of thickness) of Arctic sea ice over selected underwater transects and at selected times. Using previously and newly archived data from cruises spanning 1975 to 2001, we investigate the question of whether the average draft of Arctic sea ice has declined significantly. Our analysis differs from previous analyses both in the use of significantly more data and in the use of a multiple regression model to separate the interannual change, the annual cycle and the spatial field. The model also assumes error terms that take into account so-called `long-range' (or `long-memory') dependence. The results of our analysis support the contention that there has been a significant decline in Arctic sea-ice thickness. The overall mean ice draft from the fitted model is 2.97 m. Annual mean draft declined from a peak of 3.42 m in 1980 to a minimum of 2.29 m in 2000, a decrease of 1.13 m overall (1.25 m in thickness).