水下光谱辐射计光学特性的测试与分析

为适应高精度水下光学测量的需求，设计研制了多通道水下光谱辐射计。该辐射计可同步测量12波段的下行／上行光谱辐照度和7波段的上行光谱辐亮度。对该辐射计的主要性能指标，如余弦响应特性、浸没因子、光谱辐射精度、稳定性和重复性进行了室内测试和分析，用MonteCarlo方法模拟了阴影误差，给出并分析了现场实验数据及部分推导的物理量。结果表明，该光谱辐射计各波段的中心波长和带宽偏差小于1．6nm，稳定性优于5％，阴影误差可控制在5％之内，具有良好的余弦响应特性，满足当前定量化水色遥感现象光辐射测量的技术要求。

TEST AND ANALYSIS ON OPTICAL CHARACTERISTICS OF AN UNDERWATER MULTI-CHANNEL SPECTRAL RADIOMETER

To meet the need of high-accuracy underwater optical measurements in ocean color remote sensing, an underwater multi-channel spectral radiometer, which can measure downward irradiance and upward irradiance at twelve wavelengths and upward radiance at seven wavelengths simultaneously, have been designed and constructed. In this paper, some of the key specifications of this radiometer such as cosine characteristics of the irradiance collector, immersion factors of each channel and the spectral radiometric accuracy are tested in laboratory, shading errors are modeled by Monte Carlo simulation, the field experimental data and some optical properties derived from these data are described and analyzed. The results indicate that, the errors of the center wavelength and bandwidth of each channel are smaller than 1.6nm, which are compatible to those of remote sensors such as SeaWiFS; the stability of each channel is larger than 5%; the shading errors can bee controlled within 5%; the cosine characteristics is very good. It is very suitable for application to the in situ optical measurements in ocean color remote sensing.