基于比值法的地表反射率测量系统研究

Research on surface reflectivity measurement system based on ratio method

为了实现地表反射率长期自动化观测,提高场地定标频次,提出了一种基于比值辐射测量的地表反射率测量方法。利用场地反射率监测辐射仪和野外光谱辐照度仪进行同步观测,获取同一时间的地表辐亮度和大气总照度,通过比值法即可直接获得地表反射率参数。设计了基于标准辐射源的实验室辐射定标,分别获取辐射计和照度仪的定标系数,进而获得基于比值法测量地表反射率的输入系统参数。在室外开展了标准板测量比对实验,在可见-近红外波段比值辐射测量结果与实验室定标后参考板方向反射率数值的相对偏差在3%以内,验证了该测量系统的有效性。

In order to realize long-term automatic observation of surface reflectivity and improve the frequency of site calibration,a method of surface reflectivity measurement based on ratiometric radiation measurement is proposed.Synchronous observation is carried out by using spectally-reflective automatic spectroradiometer and hyperspectral irradiance meter.Surface radiance and total atmospheric illuminance at the same time are obtained,and the surface reflectance parameters can be obtained by the ratio method.The laboratory radiation calibration based on standard radiation source is designed to obtain the calibration coefficients of the radiometer and illuminometer respectively,and then the input system parameters based on the ratio method to measure the surface reflectivity are obtained.The standard board measurement comparison experiment is carried out outdoors.The relative deviation between the visible-near-infrared ratio radiation measurement and the reference plate reflectance value after laboratory calibration is within 3%,and the effectiveness of the measurement system is verified.