The concept of effective emissivity of nonisothermal mixed pixel and its test  

作　　者：CHEN Liangfu ZHUANG Jiali XU Xiru NIU Zheng ZHANG Renhua XIANG Yueqing 

机构地区：[1]Institute of RS and CIS,Peking University,Beijing 100871,China [2]Institute of Remote Sensing,Chinese Academy of Sciences,Beijing 100101,China [3]Institute of Geography,Chinese Academy of Sciences,Beijing 100101,China

出　　处：《Chinese Science Bulletin》2000年第9期788-795,共8页

摘　　要：Based on two preconditions, the local thermal equilibrium is satisfied and emissivities donot change with temperature, the concept of component effective emissivity of nonisothermal mixed pixel has been put forward and then the radiant directionality model of nonisothermal mixed pixel constructed from it. Our study shows that the component effective emissivity is associated with geometric structure, optical properties of target, and viewing angle, but does not depend on the component temepratures. The component temperatures can only change the ratio of component radiance to the total radiance of the mixed-pixel. The total effective emissivity of this pixel is the complement of its directional-hemisphere reflectance. After the simulation of component effective emissivity of the discrete cones and continuous vegetation canopy (winter wheat) by the Monte Carlo method, our model of radiant directionality of nonisothermal mixed pixel have been proved by lab and field measurements.Based on two preconditions, the local thermal equilibrium is satisfied and emissivities do not change with temperature, the concept of component effective emissivity of nonisothermal mixed pixel has been put forward and then the radiant directionality model of nonisothermal mixed pixel constructed from it. Our study shows that the component effective emissivity is associated with geometric structure, optical properties of target, and viewing angle, but does not depend on the component temepratures. The component temperatures can only change the ratio of component radiance to the total radiance of the mixed-pixel. The total effective emissivity of this pixel is the complement of its directional-hemisphere reflectance. After the simulation of component effective emissivity of the discrete cones and continuous vegetation canopy (winter wheat) by the Monte Carlo method, our model of radiant directionality of nonisothermal mixed pixel have been proved by lab and field measurements.

关 键 词：NONISOTHERMAL MIXED PIXEL component EFFECTIVE EMISSIVITY multiple scattering. 

分 类 号：TP79[自动化与计算机技术—检测技术与自动化装置]