Gordon H R
Appl Opt. 1992 Apr 20;31(12):2116-29. doi: 10.1364/AO.31.002116.
For interpretating remotely sensed diffuse reflectance of stratified case 1 waters, Gordon and Clark [Appl. Opt. 19, 3428 (1980)] suggested that the reflectance of a stratified ocean is identical to that of a hypothetical homogeneous ocean with a phytoplankton pigment concentration (?C?) that is a depthweighted average of the actual depth-varying concentration [C(z)]. However, this hypothesis has not been tested experimentally or theoretically. In this paper, the hypothesis is examined with Monte Carlo simulations of radiative transfer in case 1 waters by using a refined bio-optical model of the inherent optical properties of the medium. This bio-optical model, which includes separate plankton and detrital particle absorption and scattering, parameterized by the pigment concentration, is presented and tuned to Morel's statistical analysis of the average diffuse attenuation coefficient over the euphotic zone. It provides a reasonable fit to diffuse attenuation and reflectance data of individual stations. The tratification model of Morel and Berthon [Limnol. Oceanogr. 34, 1545 (1989)] characteristic of open ocean case 1 waters and a synthetic model of somewhat stronger stratification (maximum stratification of the pigment concentration |dC/dz| asymptotically equal to 0.43 mg/m(3)/m) are tested first. Two scenarios are used to relate the inherent optical properties to the pigment profile. In the first, the particle absorption and the scattering coefficients covary with C(z) and simulations show that the maximum error in the hypothesis is less, similar 2-3% for the pigment profiles considered. In contrast, in the second scenario, the particle absorption coefficient was permitted to covary with C(z), but the scattering coefficient was independent of depth. Here, errors in the hypothesis of as much as 22% were observed for the stronger stratifications. Finally, a synthetic example of strong stratification |dC/dz|, as large as 8.9 mg/m(3)/m) is examined, and errors in the hypothesis of the order of 20-25% are found when both the particle absorption and the scattering covary with C; however, for the depth-independent particle scattering case, the hypothesis can lead to large errors in R. Interestingly, for both scenarios, the ratio of reflectances at two wavelengths shows a much smaller deviation from the hypothesis than the reflectance itself.
为了解释分层的一类水体的遥感漫反射，戈登和克拉克[《应用光学》19, 3428 (1980)]提出，分层海洋的反射率与假设的均匀海洋相同，该均匀海洋的浮游植物色素浓度（(\bar{C})）是实际随深度变化的浓度[C(z)]的深度加权平均值。然而，这一假设尚未经过实验或理论验证。在本文中，通过使用介质固有光学特性的精细生物光学模型，对一类水体中的辐射传输进行蒙特卡罗模拟，来检验这一假设。给出了这个生物光学模型，它包括浮游生物和碎屑颗粒的吸收与散射，并由色素浓度参数化，且针对莫雷尔对光合层平均漫衰减系数的统计分析进行了调整。它能合理地拟合各个站点的漫衰减和反射率数据。首先测试了莫雷尔和伯特兰[《湖沼学与海洋学》34, 1545 (1989)]的一类开阔海洋水体典型分层模型以及一个分层稍强的合成模型（色素浓度的最大分层(\vert dC/dz\vert)渐近等于0.43 mg/m³/m）。使用两种情况将固有光学特性与色素剖面联系起来。在第一种情况中，颗粒吸收系数和散射系数随C(z)共同变化，模拟表明，对于所考虑的色素剖面，该假设中的最大误差较小，类似2 - 3%。相比之下，在第二种情况中，允许颗粒吸收系数随C(z)共同变化，但散射系数与深度无关。在此情况下，对于较强分层，观察到该假设中的误差高达22%。最后，研究了一个(\vert dC/dz\vert)高达8.9 mg/m³/m的强分层合成示例，当颗粒吸收和散射都随C共同变化时，发现该假设中的误差约为20 - 25%；然而，对于与深度无关的颗粒散射情况，该假设可能会导致反射率R出现较大误差。有趣的是，对于这两种情况，两个波长处反射率的比值与该假设的偏差远小于反射率本身。
