微波辐射计的定标精度直接影响其对大气参数的反演精度.基于美国大气辐射测量计划中地基微波辐射计所运用的自定标方法,推导出适用于地基微波辐射计的普遍自定标形式,并针对大气水平不均匀的情况下原始自定标方法的误差,提出一种改进的自定标方法.即原始自定标之后,在不同仰角的定标值附近搜索最佳补偿误差,使回归曲线逼近原点,相关系数接近1,从而修正由水平不均匀大气带来的误差,提高定标精度.利用双通道微波辐射计自定标后的实测数据与探空的仿真结果进行对比,验证了此方法的有效性.
The calibration precision of the microwave radiometer affects the retrieval precision of atmosphere directly.Based on the self-calibration technology of the ground-based microwave radiometer in the American Atmospheric Radiation Measurement Program,this article deduces the general forms of self-calibration by the ground-based microwave radiometer. Due to the error of self-calibration during nonstratified atmosphere conditions,an improved method of self-calibration is proposed which searches for the best expiation error of different elevations after original self-calibration.The regression curve will approach the origin and the relative coefficient will approach 1 .The measured brightness temperature of the dual-frequency microwave radiometer after self-calibration is compared with the brightness temperature simulated by the sounding data.The results show the validity of the improved self-calibration technology.