The effects of additional black carbon on the albedo of Arctic sea ice: variation with sea ice type and snow cover
The effects of additional black carbon on the albedo of Arctic sea ice: variation with sea ice type and snow cover
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DOI：
10.5194/tc-7-1193-2013
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发表时间：
2013-07
期刊：
影响因子：
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通讯作者：
A. A. Marks-A.;M. King
中科院分区：
文献类型：
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作者：
A. A. Marks-A.;M. King
抽象的。计算了裸海冰和雪覆盖海冰对黑碳加入量的响应。可见光吸收和光散射截面的一个典型的第一年和多年的海冰与“干”和“湿”雪类型。这些横截面是使用20世纪70年代实地研究的数据得出的，该研究记录了北极海冰和海冰上的雪的反射率和光穿透率。可见光吸收截面的变化表明黑碳是主要的吸光杂质。使用辐射传输模型计算了第一年和多年海冰融化对155厘米厚海冰顶部5厘米层中黑碳从1到1024 ng g−1增加的响应。与多年海冰相比，第一年海冰的冰量对额外的黑碳负荷更为敏感。在500 nm波长处，增加8 ng g−1的黑碳会导致第一年海冰的原始吸收度下降到98.7%，而多年海冰的吸收度下降到99.7%。令人惊讶的是，海冰的溶解度对高达100 ng g-1的额外黑碳没有反应。海冰上的雪层可能会减轻海冰中黑碳的影响。在海冰表面上添加0.5、1、2、5和10 cm深的湿雪层和干雪层。计算了雪表面的冰量，同时增加了底层海冰中的黑碳。一层0.5厘米厚的雪大大减少了海冰中的黑碳对表面冰的影响。2-5厘米雪层（小于雪的e折叠深度）的反射率仍然受到底层海冰的影响，但海冰中额外黑碳的影响被掩盖了。
Abstract. The response of the albedo of bare sea ice and snow-covered sea ice to the addition of black carbon is calculated. Visible light absorption and light-scattering cross-sections are derived for a typical first-year and multi-year sea ice with both "dry" and "wet" snow types. The cross-sections are derived using data from a 1970s field study that recorded both reflectivity and light penetration in Arctic sea ice and snow overlying sea ice. The variation of absorption cross-section over the visible wavelengths suggests black carbon is the dominating light-absorbing impurity. The response of first-year and multi-year sea ice albedo to increasing black carbon, from 1 to 1024 ng g−1, in a top 5 cm layer of a 155 cm-thick sea ice was calculated using a radiative-transfer model. The albedo of the first-year sea ice is more sensitive to additional loadings of black carbon than the multi-year sea ice. An addition of 8 ng g−1 of black carbon causes a decrease to 98.7% of the original albedo for first-year sea ice compared to a decrease to 99.7% for the albedo of multi-year sea ice, at a wavelength of 500 nm. The albedo of sea ice is surprisingly unresponsive to additional black carbon up to 100 ng g−1 . Snow layers on sea ice may mitigate the effects of black carbon in sea ice. Wet and dry snow layers of 0.5, 1, 2, 5 and 10 cm depth were added onto the sea ice surface. The albedo of the snow surface was calculated whilst the black carbon in the underlying sea ice was increased. A layer of snow 0.5 cm thick greatly diminishes the effect of black carbon in sea ice on the surface albedo. The albedo of a 2–5 cm snow layer (less than the e-folding depth of snow) is still influenced by the underlying sea ice, but the effect of additional black carbon in the sea ice is masked.