EAST ANTARCTIC SEA-ICE - ALBEDO, THICKNESS DISTRIBUTION, AND SNOW COVER
EAST ANTARCTIC SEA-ICE - ALBEDO, THICKNESS DISTRIBUTION, AND SNOW COVER
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DOI：
10.1029/93jc00648
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发表时间：
1993-07-15
影响因子：
3.6
通讯作者：
WARREN, SG
中科院分区：
文献类型：
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作者：
ALLISON, I;BRANDT, RE;WARREN, SG
1988年10月至12月，澳大利亚国家南极研究考察队在一次巡航中调查了东南极洲春季海冰的特征。每小时对船舶附近区域的海洋表面的覆盖率、冰厚度和几种冰类型中的每一种的积雪厚度进行估计。这些观察在船在冰中的4周期间连续进行。整个区域普遍存在较薄和较年轻的冰型，观测结果表明，按面积加权的浮冰总厚度（包括开放水域）有系统地增加，从冰缘50公里以内的仅0.2米增加到靠近海岸的0.45米。仅冰层覆盖区域的平均冰层厚度也相对较薄，从冰缘附近的0.35米到内部的0.65米不等。这些值可能是该地区冬季平均厚度的典型值。冰面上的平均积雪厚度从冰缘附近的0.05 m增加到内陆的0.15 m。平均冰浓度从冰缘附近的不到6/10增加到内部的8/10。船只观测到的浓度与被动微波卫星图像得出的浓度非常一致，但某些高浓度区域除外。在这些区域，卫星测得的浓度始终低于船上估计的浓度，这可能是因为卫星传感器无法区分在整个区域内观测到的极薄冰的可观百分比。测量了nilas，年轻的灰色冰，灰白色冰，白雪覆盖的冰的光谱。以及波长从420到1000纳米的开放水域。通过使用光谱测量值以及近红外光谱和模拟光谱太阳通量的估计值来计算全波光谱。本文利用具有代表性的全波反射率和逐时冰型观测资料，得到了东南极海冰区春季的面积平均反射率。这些面积平均的表面反射率从冰缘处的约0.35增加到距冰缘350公里处的约0.5，到南极洲海岸仍为0.5。低的平均温度部分是由于大部分的开放水域内包，但广泛的部分几乎无雪的薄冰也发挥了重要作用。
Characteristics of springtime sea ice off East Antarctica were investigated during a cruise of the Australian National Antarctic Research Expedition in October through December 1988. The fractional coverage of the ocean surface, the ice thickness, and the snow cover thickness for each of several ice types were estimated hourly for the region near the ship. These observations were carried out continuously during the 4 weeks the ship was in the ice. Thin and young ice types were prevalent throughout the region, and the observations show a systematic increase in the total area-weighted pack ice thickness (including open water area) from only 0.2 m within 50 km of the ice edge to 0.45 m close to the coast. Ice thickness averaged over the ice-covered region only is also relatively thin, ranging from 0.35 m near the ice edge to 0.65 m in the interior. These values am probably typical of average winter thickness for the area. The average snow cover thickness on the ice increased from 0.05 m near the ice edge Lo 0.15 m in the interior. Average ice concentration increased from less than 6/10 near the ice edge to 8/10 in the interior. The ship-observed concentrations were in good agreement with concentrations derived from passive microwave satellite imagery except in some regions of high concentration. In these regions the satellite-derived concentrations were consistently lower than those estimated from the ship, possibly because of the inability of the satellite sensors to discriminate the appreciable percentage of very thin ice observed within the total area. Spectral albedo was measured for nilas, young grey ice, grey-white ice, snow-covered ice. and open water at wavelengths from 420 to 1000 nm. Allwave albedo was computed by using the spectral measurements together with estimates of near-infrared albedo and modeled spectral solar flux. Area-averaged albedos for the East Antarctic sea ice zone in spring were derived from representative allwave albedos together with the hourly observations of ice types. These area-averaged surface albedos increased from about 0.35 at the ice edge to about 0.5 at 350 km from the edge, remaining at 0.5 to the coast of Antarctica. The low average albedo is in part due to the large fraction of open water within the pack, but extensive fractions of almost snow-free thin ice also play an important role.