光学浮标阴影效应的蒙特卡洛模拟

Monte Carlo Simulations of the Optical Buoy's Shading Effects

通过假设水体的漫射衰减系数和单次散射反照率等光学参数 ,运用蒙特卡罗方法模拟了浮标浮体阴影及其安装的仪器自阴影对水下光辐射测量的影响。结果表明仪器自阴影误差随仪器直径增大而增大。为使浮标引起的阴影误差小于 5 % ,直径小于 2m的浮体比较合适。如果相对于浮体中心线对称安装两个相同的仪器 ,则其中必定有一个仪器的阴影误差处于最小的状态。阴影误差还与太阳天顶角、太阳方位角、浮体倾角等因素有关 ,因此 ,浮标应该同时安装GPS定位系统、倾角和方位角等辅助传感器 ,以便在数据处理过程中根据这些辅助参数对浮标阴影误差大小进行分析。

Given the beam attenuation coefficient and single scattering albedo of sea water, the shading effects of the buoy structure on underwater optical measurements were simulated by using Monte Carlo method. The results indicated that the self-shading error increase with the increasing of the diameter of the instrument. The buoy structures shading error is a complex function of solar zenith and azimuth angle, buoy bodys diameter and inclination, and the optical properties of sea water. For general use, the diameter of the buoy body must be less than 2m so that its shading error not greater than 5 percent. If two similar sensors are symmetrically mounded on the buoy, one of the sensors must be in the case of miniature shading effects. Because buoys shading effect is a complex function, auxiliary data such as GPS, solar azimuth and buoys inclination are useful to optical data processing.