基于Gordon模型的多次散射项参数化研究

Parameterization of Multiple Scattering Item Based on the Gordon Model

针对内陆湖泊高散射特性水体，利用Hydrolight模拟软件模拟不同散射系数、风速、太阳天顶角条件下水表面以下辐照度比R（0^-）与bb／（a＋bb）的比值g，利用Gordon线性方程和二次方程对g值进行拟合，分析散射系数、风速、太阳天顶角等因素对拟合方程系数和多次散射项的影响，分析结果表明二次方程系数受太阳天顶角和风速影响的范围明显小于线性方程，并且与线性方程相比二次方程对多次散射作用的表达和实际状况以及前人研究结果更加相符，从而建立高散射特性水体中考虑多次散射作用的水表面以下辐照度比R（0^-）与bb／（a＋bb）的改进关系式，利用新的模拟数据对该表达形式进行检验，误差范围为-4．0158％～4．4981％，说明该模型能够较好地应用于R（0^-）的精确计算或利用R（0^-）准确反演固有光学属性，在湖泊水色遥感方面具有较好的应用前景．

Using the optical simulation software Hydrolight, this paper simulates the specific value g between the irradiance reflectance under water surface and the bb/（ a ＋ bb ） with different scattering coefficients, wind speeds and solar zenith angle in high scattering water body. Utilizing the Gordon linear equation and quadratic equation to fit the value g, this paper analyses the scattering coefficients,wind speeds and solar zenith angle affect on the parameter of fit equation and the item of muhiple scattering expressed by Gordon＇ s linear equation and quadratic equation. Compared to the Gordon linear equation, the result of analyses indicate that not only the range of affection that the wind speeds and solar zenith angle on the quadratic equation＇ s parameter is much narrow, but also the expression of the item of multiple scattering by quadratic equation is much more consistent to the fact condition and the result by forerunner＇s research. Accordingly, considering the item of multiple scattering in the high scattering characteristic water body in the inland lake, we finally establish the improved relationship between the R（0^- ） and bb/（ a ＋ bb ）, and perfect express equation of value g. Using the simulate data to test the equation,the range of error is -4. 015 8% -4. 498 1%, and it shows that this model can be applied to calculate the R（0^- ） exactly or inverse the inherent optical property from the R（0^- ） nicety, so the model has a good prospect in study on water color remote sensing in lake.