一维综合孔径微波辐射计海温反演精度研究

星载一维综合孔径微波辐射计(1D-ASMR)利用天线阵代替传统辐射计的大天线,具有高空间分辨率 和多入射角观测特点,是未来海温遥感的重要载荷。为评估1D-ASMR 亮温测量误差EMb 对海温反演精度的影响以 及为卫星系统的设计提供依据,文中构建了1D-ASMR 亮温仿真模型,采用多元线性回归算法(Multiple Linear Regression, MLR),定量研究了1D-ASMR 海面温度反演误差随入射角和EMb 的变化规律。其中,该1D-ASMR 工作频点为 6. 9 GHz、10. 65 GHz、18. 7 GHz、23. 8 GHz 和36. 5 GHz,极化方式为水平极化和垂直极化,入射角范围为0°~65°,EMb 范围为0~1 K。结果表明:海面温度反演误差随入射角的变化趋势受EMb 的影响,大入射角对应的反演误差低于小 入射角。采用控制变量法,分别研究不同频点EMb 对海面温度反演的影响,可得:在同一入射角下,反演误差会随着 各个频点EMb 的增大而增大,但当EMb 的大小超过0. 5 K 时,反演误差随着EMb 的增大而增大的趋势会明显减缓 且6. 9 GHz 的EMb 对海温反演误差的影响最大。

Research on the Sea Temperature Retrieval Accuracy of Spaceborne One-dimensional Synthetic Aperture Microwave Radiometer

The spaceborne one-dimensional synthetic aperture microwave radiometer (1D-ASMR) which can provide high spatial resolution and operate at multiple incidence angles uses an antenna array to replace the large antenna of a traditional radiometer. It is an important load for future sea temperature remote sensing. In order to research the influence of the 1D-ASMR brightness temperature measurement error EMb on the sea temperature retrieval accuracy and provide a basis for the design of the 1D-ASMR, a 1D-ASMR brightness temperature simulation model is built and a multiple linear regression algorithm (MLR) is used to quantitatively study the variation of the retrieval sea surface temperature error with the incidence angle and EMb. In the study, the 1D-ASMR operates at 6. 9 GHz, 10. 65 GHz, 18. 7 GHz, 23. 8 GHz and 36. 5 GHz, and each operates at vertical and horizontal polarization. In addition, the incidence angle range of the 1D-ASMR is 0°~65°, and the range of EMb is 0~1 K . The results show that the variation trend of the retrieval error with the incidence angle is affected by EMb. The retrieval error corresponding to a large incidence angle is lower than that corresponding to a small incidence angle. Using the controlled variable method to research the influence of EMb at different frequencies on the sea surface temperature retrieval, it shows that at the same incidence angle, the retrieval error will increase with the increase of EMb of each frequency, but when EMb exceeds 0. 5 K, the tendency of retrieval error to increase with the increase of EMb will significantly slow down and EMb at 6. 9 GHz has the greatest impact on the sea surface temperature retrieval error.