Spectral and Broadband Albedo of Antarctic Sea-ice Types

反照率，或反射系数，是对受辐射表面漫反射率的测量。以阳光充足的大气为光源，以海冰为漫反射表面，反照率将是返回大气的入射光的一部分。一个完美的(白色)反射表面的反照率将为1；一个完美的(黑色)吸收表面的反照率将为0。海冰反照率用于评估边缘冰区的太阳能量收支，计算大气环流和地球系统模式辐射收支中的部分太阳波段，也用于解释遥感图像数据产品。现代光谱辐射计，例如将在这次从霍巴特到南极洲的南大洋航程中使用的光谱辐射计，可以将这些反照率测量从350纳米扩大到2500纳米，从而能够验证或修正早先的估计。预计在这次研究巡航中将遇到的表面包括开阔水域、油脂冰、尼拉冰、薄煎饼冰、年轻的灰色冰、年轻的灰白色冰，以及第一年的冰。在这些表面上存在不同数量的雪也是令人感兴趣的。冰雪中的吸光杂质，包括黑碳和有机物(棕色碳)，与北冰洋冰中发现的不同，因为南极离燃烧源太远了。这可能有助于更好地了解季节周期、能量收支及其在空间范围和厚度方面的最新趋势。该项目还将扩大参加测量活动的美国和澳大利亚学生的教育经验

The albedo, or reflection coefficient, is a measure of the diffuse reflectivity of an irradiated surface. With the sunlit atmosphere as a light source, and sea-ice as a diffuse reflecting surface, the albedo would be the fraction of incident light that is returned to the atmosphere. A perfect (white) reflecting surface would have an albedo of 1; a perfect (black) absorbing surface would have an albedo of 0. The albedo of sea-ice is needed to assess the solar energy budget of the marginal ice zone, to compute the partial solar bands in radiation budgets in general circulation and earth system models, and is also needed to interpret remote sensing imagery data products.Applications requiring albedos further into the near IR, out to 2500nm, are assumed or approximated. Modern spectral radiometers, such as will be used in this campaign on a Southern Ocean voyage from Hobart to Antarctica, can extend these measurements of albedo from 350 to 2500nm, allowing earlier estimates to be verified, or corrected. Surfaces to be encountered on this research cruise are expected to include open water, grease ice, nila ice, pancake ice, young grey ice, young grey-white ice, along with first year ice. The presence of variable amounts of snow on these surfaces is also of interest. Light absorbing impurities in the snow and ice, including black carbon and organic matter (brown carbon) are different from those found in Arctic Sea ice, the Antarctic being so remote from combustion sources. This may allow better understanding of the seasonal cycles, energy budgets and their recent trends in spatial extent and thickness. The project will also broaden the educational experiences of both US and Australian students participating in the measurement campaign