风云二号静止气象卫星可见光通道辐射校正场定标方法研究

Calibration of the Visible and Near-Infrared Channels of the FY-2C/FY-2D GEO Meteorological Satellite at Radiometric Site

为了对风云二号C星(FY-2C)与D星(FY-2D)扫描辐射计(VISSR)的可见光通道进行定标,国家卫星气象中心联合多家单位在中国遥感卫星辐射校正场敦煌场开展了时间跨度达3个月的场地替代定标同步试验,获取了多组试验数据。通过使用刘京晶建立的敦煌地表反射比双向反射分布函数(BRDF)模型对实测的敦煌地表反射比数据进行方向性修正;使用6S模型计算表观反射比并进行天顶角余弦和日地距离修正;从4 d试验数据中计算得到了相对标准偏差小于5.6%(FY-2C)和2.4%(FY-2D)的4组定标系数。在不同野外环境、不同太阳几何位置参数下获得了相对一致的定标系数,说明定标算法的准确性和稳定性。

In order to calibrate the visible and near-infrared channels of FY-2C ＆ FY-2D＇s visible and infrared spinscanning radiometer （VISSR）, National Satellite Meteorlogical Center （NSMC） associated with other organizations went to China radiometric calibration site of remote sensing satellite-Dunhuang to take site vicarious calibration synchronous experiment. The experiment continued for three months and a lot of experimental data have been gotten. From four days＇ experimental data, the calibration coefficients with relative standard deviations below 5.6 % （FY-2C） and 2.4% （FY-2D） are calculated. The reflectance of Dunhuang was corrected by the bidirectional reflectance distribution function （BRDF） model calculated by Liu Jingjing, the apparent reflectance was calculated by the use of 6S model and was corrected by the sun zenith cosine and sun-earth distance. From the different experimental data measured in different field conditions and sun position, the accordant calibration coefficients were gotten, and it showed the veracity and stability of the calibration arithmetic.