Variations in Sea Ice Thickness in the Polar Regions

• Main Author: Wadhams, Peter
• Other Authors: CAMBRIDGE UNIV (UNITED KINGDOM)
• Format: Text
• Language: English
• Published: 1992
• Subjects: Snow; Ice and Permafrost; Meteorology; *POLAR REGIONS; *SEA ICE; *CLIMATE; *ENVIRONMENTAL IMPACT; CONSISTENCY; DRIFT; DRILLING; ICE; OCEANS; PROFILES; SEASONS; SONAR; THICKNESS; VARIATIONS; GREENHOUSE EFFECT; *Ice thickness; *Global climate change; Component Reports; Antarctic; Arctic; Fairbanks; The Antarctic; Weddell; Weddell Sea; Antarc*; Climate change; Ice; permafrost; Sea ice; Alaska
• Online Access: http://www.dtic.mil/docs/citations/ADP007260; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADP007260

An overview paper is presented on the evidence for variations in sea ice thickness in the polar regions. Most ice thickness data in the Arctic come from upward-looking sonar profiling by submarines. The available dataset is large, but the sampling has been necessarily unsystematic, so that only very few cases exist of directly comparable profiles from different years or seasons in the same location. Comparisons made so far are reviewed. They show that large fluctuations of mean ice thickness can occur over significant areas (15% over 300,000 km2) but that these are associated strongly with variability in the field of ice motion in regions upstream of land boundaries, where ice deformation is usually an important contributor to the mean draft. Comparisons made in the Trans Polar Drift Stream far from land boundaries show a remarkable consistency in mean draft between seasons and years. In the Antarctic ice thickness data are much sparser, and most have been obtained by direct drilling. Most of the available winter data come from only two cruises, the 1986 and 1989 Weddell Sea cruises of F.S. Polarstern. They show that first-year ice, which comprises most of the ice in the Antarctic, is remarkably thin, with a mean thickness of about 60 cm when undeformed. Second-year ice, found in the western Weddell Sea, is much thicker (1.17 m mean thickness when undeformed). This article is from 'Proceedings of the International Conference on the Role of the Polar Regions in Global Change Held in Fairbanks, Alaska on 11-15 June 1990. Volume 1', AD-A253 027, p4-13. See also Volume 2, AD-A253 028.