论文部分内容阅读
凭借能够测量海面辐射全部4个Stokes参数的能力,全极化微波辐射计成为测量海面风场的一种新手段。由于风向信号仅仅只有几K甚至更小的振幅,故对全极化微波辐射计极化通道的定标精度要求颇高。使用WindSat实测亮温及其海面参数匹配数据集,基于海面风向信号的谐波特征,对WindSat极化通道亮温的定标偏差和仪器噪声进行了计算和分析。研究结果表明:WindSat的10.7、18.7和37.0GHz这3个频率的极化通道均存在明显的定标偏差,并且该定标偏差会随着升轨和降轨、前向刈幅和后向刈幅等不同观测模态发生变化。另外,WindSat极化通道的仪器噪声较小,其中T3的仪器噪声在0.2K以内,T4的仪器噪声在0.1K以内。
With the ability to measure all four Stokes parameters of the sea surface radiation, the fully polarized microwave radiometer becomes a new measure of the sea surface wind field. As the wind direction signal is only a few K or even smaller amplitude, so the polarization of the polarization channel of fully polarized microwave radiometer calibration accuracy is high. WindSat measured brightness temperature and its sea surface parameter matching dataset were used to calculate and analyze the calibration deviation of WindSat polarization channel temperature and instrument noise based on the harmonic characteristics of sea surface wind direction signal. The results show that there are obvious calibration deviations in the WindSat polarization channels at 10.7, 18.7 and 37.0 GHz, and the scaling error will vary with ascending and descending trajectories, forward swath and backward mowing Different observation modes such as amplitude change. In addition, WindSat polarization channel instrument noise is small, including T3 instrument noise within 0.2K, T4 instrument noise within 0.1K.