利用敦煌辐射校正场对FY-2B静止气象卫星进行可见光通道的在轨辐射定标

RADIOMETRIC CALIBRATION ON ORBIT FOR FY-2B METEOROLOGICAL SATELLITE'S VISIBLE CHANNELS WITH THE RADIOMETRIC CALIBRATION SITE OF DUNHUANG

FY 2B由于杂散光的影响 ,其可见光通道的发射前定标存在较大误差。利用敦煌戈壁滩辐射校正场可进行FY 2B可见光通道的在轨绝对定标。由于FY 2B对于敦煌场区的卫星天顶角接近 5 0°,需要进行场地的方向特性BRDF修正。 2 0 0 2年 7月对FY 2B进行了场地地表反射率、大气消光、探空等项同步测量 ,并对场地的方向特性进行了测量。资料处理结果表明 ,FY 2B可见光通道杂散光可影响定标精度达 2 0 %。长期监视表明FY 2B可见光通道探测器输出十分稳定。该文将 4个可见光通道探测器场地定标得出的定标查找表列出 。

Pre-launch calibration of the FY-2B's visible channels has much error due to the influence of stray light. The radiometric calibration on orbit for FY-2B's visible channels might be running with the radiometric calibration site of Dunhuang's Gobi. There are must calibrated the BRDF of bi-direction characteristic of Dunhuang's site, because the zenith is close to 50°. The reflectance of the Gobi, light extinction of atmosphere and radiosonde observation were measured in synchronization for FY-2B in July 2002, while the bi-direction characteristics of the site were measured. The data processed results indicate that the calibration precision are debased 20% due to influence of stray light for FY-2B's visible channels, and the output of FY-2B's visible channels is very stabilization after long stakeout. The calibration tables calibrated by the site of four visible channels were listed.