The spatial distribution of snow cover on the central Arctic sea ice is investigated here based on the observations made during the Third Chinese Arctic Expedition. Six types of snow were observed during the expeditio...The spatial distribution of snow cover on the central Arctic sea ice is investigated here based on the observations made during the Third Chinese Arctic Expedition. Six types of snow were observed during the expedition： new/recent snow, melt-fi＇eeze crust, icy layer, depth hoar, coarse-grained, and chains of depth hoar. Across most measurement areas, the snow surface was covered by a melt-freeze crust 2-3 cm thick, which was produced by alternate strong solar radiation and the sharp temperature decrease over the summer Arctic Ocean. There was an intermittent layer of snow and ice at the base of the snow pack. The mean bulk density of the snow was 304.01~29.00 kg/m3 along the expedition line, and the surface values were generally smaller than those of the sub- surface, confirming the principle of snow densification. In addition, the thicknesses and water equivalents of the new/recent and total-layer snow showed a decreasing trend with latitude, suggesting that the amount of snow cover and its spatial variations were mainly determined by precipitation. Snow temperature also presented significant variations in the vertical profile, and ablation and evaporation were not the primary factors in the snow assessment in late summer. The mean temperature of the surface snow was -2.01±0.96℃, which was much higher than that observed in the interface of snow and sea ice.展开更多
基金funded by the Opening Founding of the State Key Laboratory of Cryospheric Sciences (SKLCS 09-07)the Special Polar Program of the Ministry of Finance (CHINARE2012-02-02)the National Natural Science Foundation of China (NSFC) (41121001)
文摘The spatial distribution of snow cover on the central Arctic sea ice is investigated here based on the observations made during the Third Chinese Arctic Expedition. Six types of snow were observed during the expedition： new/recent snow, melt-fi＇eeze crust, icy layer, depth hoar, coarse-grained, and chains of depth hoar. Across most measurement areas, the snow surface was covered by a melt-freeze crust 2-3 cm thick, which was produced by alternate strong solar radiation and the sharp temperature decrease over the summer Arctic Ocean. There was an intermittent layer of snow and ice at the base of the snow pack. The mean bulk density of the snow was 304.01~29.00 kg/m3 along the expedition line, and the surface values were generally smaller than those of the sub- surface, confirming the principle of snow densification. In addition, the thicknesses and water equivalents of the new/recent and total-layer snow showed a decreasing trend with latitude, suggesting that the amount of snow cover and its spatial variations were mainly determined by precipitation. Snow temperature also presented significant variations in the vertical profile, and ablation and evaporation were not the primary factors in the snow assessment in late summer. The mean temperature of the surface snow was -2.01±0.96℃, which was much higher than that observed in the interface of snow and sea ice.
