Spectral and Broadband Albedo of Antarctic Sea-ice Types

南极海冰类型的光谱和宽带反照率

• 批准号: 1141275
• 负责人: Stephen Warren
• 金额: $ 13.25万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1141275&HistoricalAwards=false
• 关键词: Spectral; Broadband; Albedo; Antarctic; Sea

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

反射系数是被照射表面漫反射率的量度。以阳光照射的大气层作为光源，海冰作为漫反射表面，反射率将是入射光返回大气层的部分。一个完美的（白色）反射表面的反射系数为1;一个完美的（黑色）吸收表面的反射系数为0。海冰的反射率用于评估边缘冰区的太阳能收支，计算大气环流和地球系统模式中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行中使用的光谱辐射计，可以将这些测量范围从350纳米扩展到2500纳米，从而可以验证或纠正早期的估计。 在这次研究巡航中遇到的表面预计包括开放水域，油脂冰，尼拉冰，煎饼冰，年轻的灰色冰，年轻的灰白色冰，沿着第一年冰。在这些表面上存在不同量的雪也是有趣的。雪和冰中的光吸收杂质，包括黑碳和有机物（棕碳），与北极海冰中发现的不同，南极远离燃烧源。这可能有助于更好地了解季节周期、能量收支及其最近的空间范围和厚度趋势。该项目还将扩大参与测量活动的美国和澳大利亚学生的教育经验