Theoretical estimates of light reflection and transmission by spatially complex and temporally varying sea ice covers
Theoretical estimates of light reflection and transmission by spatially complex and temporally varying sea ice covers
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DOI：
10.1029/jc095ic06p09557
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发表时间：
1990-06
影响因子：
--
通讯作者：
D. Perovich
中科院分区：
文献类型：
--
作者：
D. Perovich
雪和冰盖对可见光和近红外波长的光的反射、吸收和传输对于许多地球物理问题是重要的。本文的重点是空间非均匀和时间变化的海冰对光的反射和透过。这是使用一个双流，多层辐射传输模型在400到1000 nm的波长范围内进行研究的。该模型计算简单，并利用了现有的海冰光学性质的实验数据。冰盖的特征是一种分层的介质，由九种不同类型的雪和冰组成。提供了三个案例研究，说明了(1)空间不均匀的冰盖、(2)经历融化循环的均匀冰盖和(3)时间变化的空间变化的冰盖的光谱反照率、透射率和透光性有效辐射(PAR)的值。结果表明，积雪深度和冰层厚度的小尺度水平变化可以导致光透射率变化3个数量级以上。预计在融化季节的早期，随着冰盖从不透明的、白雪覆盖的介质演变为半透明的裸露或池塘冰，光的反射和透射率将发生戏剧性的变化。
The reflection, absorption, and transmission of light at visible and near-infrared wavelengths by snow and ice covers is important for a number of geophysical problems. The focus of this paper is on the reflection and transmission of light by spatially inhomogeneous and temporally varying sea ice covers. This is investigated using a two-stream, multilayer radiative transfer model in the wavelength region from 400 to 1000 nm. The model is computationally simple and utilizes the available experimental data on the optical properties of sea ice. The ice cover is characterized as a layered medium composed of selections from nine distinct snow and ice types. Three case studies are presented illustrating values of spectral albedo, transmittance, and transmitted photosynthetically active radiation (PAR) for (1) a spatially inhomogeneous ice cover, (2) a uniform ice cover as it undergoes a melt cycle, and (3) a temporally changing spatially variable ice cover. Results indicate that small-scale horizontal variations in snow depth and ice thickness can cause light transmission to change over 3 orders of magnitude. Dramatic changes in light reflection and transmission are predicted in the early part of the melt season as the ice cover evolves from an opaque, snow-covered medium to translucent bare or ponded ice.