CBERS-02星CCD波段平均太阳辐照度反演及应用

卫星图像波段平均太阳辐照度是计算表观反射率的重要参数。本文采用两种方法对CBERS-02星CCD波段平均太阳辐照度进行了计算,一种方法是利用大气辐射传输软件SBDART模拟大气顶部的太阳光谱曲线,结合CBERS-02星CCD波段响应曲线,计算1～4波段的平均太阳辐照度;另一种方法是用6S模型对波段平均太阳辐照度进行计算。为验证计算结果,用同样的方法,计算了LandsatTM5和ETM的波段平均太阳辐照度,与Landsat公布的数据进行对比,结果表明,用模拟的太阳光谱曲线的计算结果更准确。以2005年8月24日的一景图像为例,计算了图像的表观反射率,经6S模型大气校正后,反演了地表反射率,与地面实测的地表反射率进行了对比,除第四波段误差为4%外,其余1～3波段误差仅为0.01%。

Retrieval and Application of Band Mean Solar Irradiance of CBERS-02 CCD

Mean solar spectral irradiance of satellite is an important parameter for the computation of appearance reflectance.In this paper two methods are used to compute the mean solar spectral irradiances of CBERS-02 CCD,one method is that using the radiation transfer software SBDART to simulate the curves of exo-atomosphere solar spectral irradiances,with the combination of the spectral response curve of CBERS-02 CCD,the mean solar spectral irradiances of band1 to band4 are computed;another method is to use 6S model for the computation.To valid the computing methods,these two methods are used to compute the mean solar spectral irradiances of TM and ETM,compared to the data provided by the government,it is showed that the result of the first method is better than that of the second one.Taking the scene obtained on August 24th, 2005 as an example,the appearance reflectance is computed,after the atmospheric correction using 6S model,the ground reflectance is retrieved,and compared to the measured reflectance value,the relative error of band1 to band2 is 0.01%,and the relative error of band4 is 4%.