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介绍一种简单的新方法以实现对野外有限区域内粗糙表面反射率的测算, 新方法的测量主要步骤有:1) 在目标表面正上方约50 cm处正反安装2个太阳辐射仪;2) 通过遮光罩限制下表面辐射仪接收到仅来自目标表面的反射量, 并相应地记录入射太阳辐射和反射辐射;3) 在目标区域表面上覆盖一张具有非选择性光谱且已知反射率的参照板, 并记录入射太阳辐射和反射辐射.理论分析发现该方法可消除仪器阴影和周围环境变量的影响.对比ASTME1918-06规范计算结果表明新方法可通过测量有限范围内目标区域, 如1 m2正方形或直径1m等各种均质粗糙表面反射率并估算整体的反射率, 具有操作简单、可靠、实用的特点.“,”This paper establishes a new method to measure and calculate the reflectivity for a rough surface in timited area. The measurement procedure includes three steps:1) centering and leveling two pyranometers back to back over target area with 50 cm nigh;2) installing a baffle concentrically to the lower pyranometer such that the sensor receives the reflection from the target only, then recording the incident and reflected radiations respectively;3) covering the target area with a spectrally unselective solar-opaque mask, then recording the incident and reflected radiation respectively. The theory of the new method reveals that the errors caused by the shallow of the instrument are eliminated.The new method is practically simpler and require less testing time, compared to the existing method such as ASTM E1918-06.