Snyder W C, Wan Z
Appl Opt. 1996 May 1;35(13):2216-20. doi: 10.1364/AO.35.002216.
Land surface temperature algorithms for the moderate resolution imaging spectroradiometer satellite instrument will require the spectral bidirectional reflectance distribution function (BRDF) of natural surfaces in the thermal infrared. We designed the spectral infrared bidirectional reflectance and emissivity instrument to provide such measurements by the use of a Fourier transform infrared spectrometer. A problem we encountered is the unavoidable surface heating caused by the source irradiance. For our system, the effects of the heating can cause a 30% error in the measured BRDF The error caused by heating is corrected by temporally curve fitting the radiance signal. This curve-fitting technique isolates the radiance caused by reflected irradiance. With this correction, other factors dominate the BRDF error. It is now ~5% and can be improved further. The method is illustrated with measurements of soil BRDF.
用于中分辨率成像光谱仪卫星仪器的陆地表面温度算法将需要热红外波段自然表面的光谱双向反射分布函数（BRDF）。我们设计了光谱红外双向反射率和发射率仪器，通过使用傅里叶变换红外光谱仪来进行此类测量。我们遇到的一个问题是源辐照度不可避免地导致表面升温。对于我们的系统，升温效应会在测量的BRDF中造成30%的误差。通过对辐射信号进行时间曲线拟合来校正由升温引起的误差。这种曲线拟合技术分离出由反射辐照度引起的辐射。通过这种校正，其他因素成为BRDF误差的主要来源。目前误差约为5%，并且可以进一步改进。该方法通过土壤BRDF的测量进行了说明。
