Crucial physical characteristics of sea ice in the Arctic section of 143-180W during August and early September 2008

• Published in: 海洋学报：英文版 Vol. 31; no. 4; pp. 65 - 75
• Main Author: LEI Ruibo LI Zhijun LI Na LU Peng CHENG Bin
• Format: Journal Article
• Language: English
• Published: 2012
• Subjects: 低纬度地区; 北极地区; 平均密度; 海冰厚度; 物理特性; 航行记录; 覆盖面; 高纬度地区
• ISSN: 0253-505X; 1869-1099

Sea-ice physical characteristics were investigated in the Arctic section of 143~-180~W during Au- gust and early September 2008. Ship-based observations show that both the sea-ice thickness and concentration recorded during southward navigation from 30 August to 6 September were remark- ably less than those recorded during northward navigation from 3 to 30 August, especially at low latitudes. Accordingly, the marginal ice zone moved from about 74.0~N to about 79.5~N from mid-August to early September. Melt-pond coverage increased with increasing latitude~ peaking at 84.4~N, where about 27% of ice was covered by melt ponds. Above this latitude, melt-pond coverage decreased evidently as the ice at high latitudes experienced a relatively short melt season and commenced its growth stage by the end of August. Regional mean ice thickness increased from 0.8 （~=0.5） m at 75.0~N to 1.5 （＋0.4） m at 85.0~N along the northward navigation while it decreased rapidly to 0.6 （-t-0.3） m at 78.0~N along the southward navigation. Because of relatively low ice concentration and thin ice in the investigated Arctic sector, both the short-term ice stations and ice camp could only be set up over multiyear sea ice. Observations of ice properties based on ice cores collected at the short-term ice stations and the ice camp show that all investigated floes were essentially isothermal with high temperature and porosity, and low density and salinity. Most ices had salinity below 2 and mean density of 800-860 kg/m3. Significant ice loss in the investigated Arctic sector during the last 15 a can be identified by comparison with the previous observations.