Relationships between inherent optical properties and the depth of penetration of solar radiation in optically complex coastal waters
Relationships between inherent optical properties and the depth of penetration of solar radiation in optically complex coastal waters
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DOI：
10.1002/jgrc.20182
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发表时间：
2013-05-01
影响因子：
3.6
通讯作者：
McKee, David
中科院分区：
文献类型：
--
作者：
Cunningham, Alex;Ramage, Leanne;McKee, David
向下的平面辐照度的衰减可以通过（K）除以bar（d）（E-10%，λ）来量化，从表面到深度计算的漫射衰减系数，其中波长λ处的辐照度E-d福尔斯到其表面值的10%。Gordon（1989）和Lee等人（2005 a）的理论研究表明，（K）超过bar（d）（E-10%，λ）可以从吸收系数a（λ）和反向散射系数B（B）（λ）导出，使用包含太阳天顶角（θ（α））或地下分布函数（D-0）的方程和由辐射传输模型导出的经验系数。然而，这些结果还没有得到验证，对现场测量。因此，我们使用英国沿海沃茨100个站点的a（lambda）、B（B）（lambda）和（K）与bar（d）（E-10%，lambda）的测量值评估了两种模型的性能。从Lee等人（2005 a）的模型中获得了最佳结果，其中在440 nm至665 nm范围内，超过90%的预测（K）/bar（d）（E-10%，lambda）值在原位测量值的+/-0.1 m（-1）范围内。在490 nm处的（K）/条（d）（E-10%，λ）与真光区中点深度的倒数（z（10%），PAR）之间发现了强线性关系（R-2 > 0.95，平均相对差5.4%）。这使得（z（10%），PAR）可以从a（490 nm），B（B）（490 nm）和θ（a）的测量值中预测，使用Lee等人的模型作为中间步骤，在我们的数据集所覆盖的2.5-25.0 m范围内RMS误差为1.25 m。
The attenuation of downward planar irradiance can be quantified by (K) over bar (d) (E-10%, lambda), the diffuse attenuation coefficient calculated from the surface to the depth where the irradiance E-d at wavelength lambda falls to 10% of its surface value. Theoretical studies by Gordon (1989) and Lee et al. (2005a) suggest that (K) over bar (d) (E-10%, lambda) can be derived from the absorption coefficient, a(lambda) and the backscattering coefficient, b(b)(lambda), using equations incorporating either the solar zenith angle (theta(a)) or the subsurface distribution function (D-0) and empirical coefficients derived by radiative transfer modeling. These results have not, however, been validated against in situ measurements. We have therefore assessed the performance of both models using measurements of a(lambda), b(b)(lambda), and (K) over bar (d) (E-10%, lambda) for 100 stations in UK coastal waters. Best results were obtained from the Lee et al. (2005a) model, for which over 90% of the predicted (K) over bar (d) (E-10%, lambda) values in the 440 nm to 665 nm range were within +/-0.1 m(-1) of those measured in situ. A strong linear relationship (R-2 > 0.95, mean relative difference 5.4%) was found between (K) over bar (d) (E-10%, lambda) at 490 nm and the reciprocal of the depth of the midpoint of the euphotic zone (z(10%), PAR). This allowed (z(10%), PAR) to be predicted from measured values of a(490 nm), b(b)(490 nm) and theta(a), using the Lee et al. model as an intermediate step, with an RMS error of 1.25 m over the 2.5-25.0 m range covered by our data set.