全天空红外测云系统辐射传感器的替代定标

VICARIOUS CALIBRATION ON THE SENSOR OF WHOLE SKY INFRARED CLOUD MEASURING SYSTEM

为了实现全天空红外测云系统辐射传感器业务运行过程中的定标,提出了一种以晴空辐射为标准辐射场的替代定标方法.根据SBDART辐射传输模式计算出的晴空大气向下红外辐射以及辐射传感器对天空观测的输出量化值,利用线性回归方法确定出传感器全场各像元的响应率和偏移量.定标结果分析表明,响应率不确定度为2.03DN unit/(W.m-2.sr-1),偏移量具有明显的正态分布特征,为空间随机噪声.标准黑体检验表明温度反演平均误差不超过±1.5℃,能够满足系统定量化应用的要求.

In order to calibrate the sensor of whole sky infrared cloud measuring system（WSIRCMS） in operational period, a vicarious calibration method was proposed based on the clear sky infrared radiance field. The response rates and the offsets of the whole array were obtained by linear regression methodon the basis of the clear sky infrared radiance modeled by SBDART, and the DN values were observed. Our results show that the uncertainty of the response rates is 2.03DN unit/ （W·m^-2 · sr^-1）, and the offsets have a character of normal distribution which can be considered as spatial random noise. The average error of temperature retvieved is within ±1.5℃ according to the validation of the blackbody test data, which can satisfy the quantitative applications of WSIRCMS.