New insights into radiative transfer within sea ice derived from autonomous optical propagation measurements
New insights into radiative transfer within sea ice derived from autonomous optical propagation measurements
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DOI：
10.5194/tc-15-183-2021
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发表时间：
2021-01-11
期刊：
影响因子：
5.2
通讯作者：
Hoppmann, Mario
中科院分区：
文献类型：
--
作者：
Katlein, Christian;Valcic, Lovro;Hoppmann, Mario
短波太阳辐射通过极地海洋海冰覆盖层的辐射传递是大气-冰-海洋界面能量分配的一个关键方面。需要详细了解海冰覆盖如何反射和透射阳光，以便准确表示气候和生态系统模型中的关键过程，例如冰-冰反馈。由于与冰内部测量相关的挑战，大多数关于海冰辐射传输的信息都是通过海冰上方和下方的光学测量获得的。为了提高我们对冰本身内辐射传输过程的理解，我们开发了一种新型仪器，该仪器配备了许多可以冻结到冰中的多光谱光传感器。第一个原型由2.3米长的48个侧向平面辐照度传感器组成，垂直间距为0.05米，于2018年8月下旬部署在地理北极，在秋季期间提供冰盖内的自主垂直分辨光测量。在这里，我们提出了这种仪器的第一个结果，讨论了原型的优点和应用，并提供了第一个新的见解海冰本身内的辐射传输的时空方面。特别是，我们调查如何测得的衰减系数与光学特性的冰袋，并表明，侧向平面辐照度的测量是等效的总标量辐照度的测量。
The radiative transfer of shortwave solar radiation through the sea ice cover of the polar oceans is a crucial aspect of energy partitioning at the atmosphere-ice-ocean interface. A detailed understanding of how sunlight is reflected and transmitted by the sea ice cover is needed for an accurate representation of critical processes in climate and ecosystem models, such as the ice-albedo feedback. Due to the challenges associated with ice internal measurements, most information about radiative transfer in sea ice has been gained by optical measurements above and below the sea ice. To improve our understanding of radiative transfer processes within the ice itself, we developed a new kind of instrument equipped with a number of multispectral light sensors that can be frozen into the ice. A first prototype consisting of a 2.3 m long chain of 48 sideward planar irradiance sensors with a vertical spacing of 0.05 m was deployed at the geographic North Pole in late August 2018, providing autonomous, vertically resolved light measurements within the ice cover during the autumn season. Here we present the first results of this instrument, discuss the advantages and application of the prototype, and provide first new insights into the spatiotemporal aspect of radiative transfer within the sea ice itself. In particular, we investigate how measured attenuation coefficients relate to the optical properties of the ice pack and show that sideward planar irradiance measurements are equivalent to measurements of total scalar irradiance.