Penetration of UV-visible solar radiation in the global oceans: Insights from ocean color remote sensing
Penetration of UV-visible solar radiation in the global oceans: Insights from ocean color remote sensing
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全球海洋中紫外-可见太阳辐射的穿透：海洋颜色遥感的见解
DOI：
10.1002/jgrc.20308
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发表时间：
2013-09-01
影响因子：
3.6
通讯作者：
Brewin, Robert
中科院分区：
文献类型：
--
作者：
Lee, Zhongping;Hu, Chuanmin;Brewin, Robert
太阳辐射在海洋中的穿透率由衰减系数（K-d（））决定。根据辐射传输理论，K-d是入射光的角分布和水的吸收和后向散射系数的函数。由于这些光学产品现在通常由卫星测量产生，因此将经验K-d演变为半解析K-d是合乎逻辑的，该半解析K-d不仅在光谱上灵活，而且还明确地考虑了太阳角效应。在这里，Lee等人（2005 b）开发的半解析模型进行了修订，以解释从短波长到长波长的分子和颗粒散射之间的相函数的移位。此外，使用从贫营养海洋到沿海沃茨独立收集的现场数据，覆盖全球海洋>99%的K-d范围，对半解析推导的K-d进行了评估，发现与测量数据在约7- 26%范围内一致。将改进后的处理系统应用于中分辨率成像光谱仪（MODIS）测量，揭示了全球海洋中UVA-可见光辐射的穿透情况，并对拉曼效应进行了经验修正。结果表明，蓝绿辐射对大多数海洋沃茨的穿透深度比通常使用的真光层深度约深30-40%;并证实在50-70 m深度处，大多数贫营养沃茨中仍有约10%的表面UVA辐射（360 nm）。结果表明，有必要修改或扩大从卫星海洋颜色测量的光衰减产品，以更适用于海洋物理和海洋地球化学的研究。
Penetration of solar radiation in the ocean is determined by the attenuation coefficient (K-d()). Following radiative transfer theory, K-d is a function of angular distribution of incident light and water's absorption and backscattering coefficients. Because these optical products are now generated routinely from satellite measurements, it is logical to evolve the empirical K-d to a semianalytical K-d that is not only spectrally flexible, but also the sun-angle effect is accounted for explicitly. Here, the semianalytical model developed in Lee et al. (2005b) is revised to account for the shift of phase function between molecular and particulate scattering from the short to long wavelengths. Further, using field data collected independently from oligotrophic ocean to coastal waters covering >99% of the K-d range for the global oceans, the semianalytically derived K-d was evaluated and found to agree with measured data within approximate to 7-26%. The updated processing system was applied to MODIS measurements to reveal the penetration of UVA-visible radiation in the global oceans, where an empirical procedure to correct Raman effect was also included. The results indicated that the penetration of the blue-green radiation for most oceanic waters is approximate to 30-40% deeper than the commonly used euphotic zone depth; and confirmed that at a depth of 50-70 m there is still approximate to 10% of the surface UVA radiation (at 360 nm) in most oligotrophic waters. The results suggest a necessity to modify or expand the light attenuation product from satellite ocean-color measurements in order to be more applicable for studies of ocean physics and biogeochemistry.