Seaborne measurements of near infrared water-leaving reflectance: The similarity spectrum for turbid waters
Seaborne measurements of near infrared water-leaving reflectance: The similarity spectrum for turbid waters
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DOI：
10.4319/lo.2006.51.2.1167
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发表时间：
2006-03-01
影响因子：
4.5
通讯作者：
Moore, G
中科院分区：
文献类型：
--
作者：
Ruddick, KG;De Cauwer, V;Moore, G
本文介绍了混浊沃茨离水反射率的理论和海上测量结果。根据理论，近红外光谱的形状主要由纯水吸收决定，因此几乎是不变的。通过在780 nm处归一化来定义“相似性”NIR反射光谱。此光谱计算从海运反射率测量，并与来自实验室的水吸收测量。从理论上分析了影响相似谱形状的因素，并通过辐射传输模拟进行了分析。这些模拟表明，相似性谱对于中等浑浊（例如，在780 nm处的10（-4）量级的离水反射率或0.3 g/m（-3）量级的总悬浮物浓度）到极浑浊（例如，在780 nm处的反射率为10（-1）级或总悬浮物为200 g/m（-3）级）。分析了测量的不确定性，指出了海气界面校正对低反射率测量的重要性。概述了近红外相似光谱在海洋水色数据大气校正和混浊沃茨中海上、空中和星载反射率测量质量控制中的应用。
Theory and seaborne measurements are presented for the near infrared (NIR: 700-900 nm) water-leaving reflectance in turbid waters. According to theory, the shape of the NIR spectrum is determined largely by pure water absorption and is thus almost invariant. A "similarity" NIR reflectance spectrum is defined by normalization at 780 nm. This spectrum is calculated from seaborne reflectance measurements and is compared with that derived from laboratory water absorption measurements. Factors influencing the shape of the similarity spectrurn are analyzed theoretically and by radiative transfer simulations. These simulations show that the similarity spectrum is valid for waters ranging from moderately turbid (e.g., water-leaving reflectance at 780 nm of order 10(-4) or total suspended matter concentration of order 0.3 g m(-3)) to extremely turbid (e.g., reflectance at 780 nm of order 10(-1) or total suspended matter of order 200 g m(-3)). Measurement uncertainties are analyzed, and the air-sea interface correction is shown to be critical for low reflectances, Applications of the NIR similarity spectrum to atmospheric correction of ocean color data and to the quality control of seaborne, airborne, and spaceborne reflectance measurements in turbid waters are outlined.