Midnight Sun to Polar Night: A Model of Seasonal Light in the Barents Sea
Midnight Sun to Polar Night: A Model of Seasonal Light in the Barents Sea
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DOI：
10.1029/2022ms003198
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发表时间：
2022-09
影响因子：
6.8
通讯作者：
Stacey Connan‐McGinty;N. Banas;J. Berge;F. Cottier;Stephen Grant;G. Johnsen;Tomasz P. Kopec;M. Porter;D. McKee
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文献类型：
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作者：
Stacey Connan‐McGinty;N. Banas;J. Berge;F. Cottier;Stephen Grant;G. Johnsen;Tomasz P. Kopec;M. Porter;D. McKee
北极海洋生态系统受到该区域极端季节性光照的强烈影响。准确测定光照对于全面了解动物和水生藻类种群的动态至关重要。目前的水下光场参数化方法依赖于来自卫星或表面辐射测量的短波辐射(300-3000 nm)估计，以填充完整的辐射传输软件。由于北极许多地区无法进入，测量数据并不广泛获得。这项研究提出了巴伦支海无冰条件下光谱分辨水下光的模型。在给定位置和时间的情况下，该模型解释了受当地云层调制的太阳、月球和银河光源在海洋表面的光合作用有效辐射(PAR，400-700 nm)范围(ED PAR)中的下行光谱辐照度。我们演示了在宽带PAR和光谱域中验证的在全年延伸到极地之夜的能力。使用为巴伦支海开发的扩散衰减的生物光学模型，我们显示了时空范围内非均匀水柱深度的准确计算，并通过来自NY-älesund，Svalbard的ArcLight天文台和部署在巴伦支海的现场辐射传感器的时间序列辐射数据进行了验证。最后，与最先进的水柱平均辐射传输模型相比，在阴天条件下，典型的平均绝对误差为<；1μmol m−2 S−1(ED PAR)(晴天条件下为<；6μmol m−2 S−1)，并缩短了因子20的执行时间。
Arctic marine ecosystems are strongly influenced by the extreme seasonality of light in the region. Accurate determination of light is essential for building a comprehensive understanding of the dynamics of animal and aquatic algae populations. Current approaches to underwater light field parameterisations rely upon shortwave radiation (300–3000 nm) estimates from satellites or surface radiometry measurements to populate full radiative transfer software. Due to the inaccessibility of many regions in the Arctic, measured data is not widely available. This study presents a model of spectrally resolved underwater light in ice‐free conditions in the Barents Sea. Given a location and time, the model accounts for downwelling spectral irradiance in the photosynthetically active radiation (PAR, 400–700 nm) range (ED PAR) at the ocean surface from solar, lunar, and galactic light sources, modulated by local cloud cover. We demonstrate the ability to extend over the full year into the period of Polar Night, validated in both broadband PAR and spectral domains. Using a bio‐optical model of diffuse attenuation developed for the Barents Sea, we show accurate calculations to depth for inhomogeneous water columns over a spatial‐temporal range, validated against time series irradiance data from the ArcLight observatory in Ny‐Ålesund, Svalbard and in‐situ irradiance sensors deployed in the Barents Sea. Finally, in comparison to state‐of‐the‐art radiative transfer models, averaged over the water column we demonstrate a typical mean absolute error of <1 μmol m−2 s−1 in ED PAR for overcast conditions (<6 μmol m−2 s−1 for clear‐sky) and reduced execution time of factor 20.