星载高光谱微波辐射计大气温度廓线反演的仿真与分析

Simulation and analysis of atmospheric temperature profiles retrieval using spaceborne hyperspectral microwave radiometer

  • 摘要: 高光谱微波辐射计相比于传统辐射计通道数量大幅度提升,可获得连续、高频率分辨率的亮温探测结果,但由于通道间相关性以及通道细分后灵敏度下降等问题,其对于高光谱微波遥感能力的提升需要进一步的理论研究支撑。针对上述问题及当前未有对地观测高光谱微波辐射计在轨运行载荷的情况,构建星载高光谱微波辐射计亮温仿真与大气温度廓线反演分析平台,该平台基于辐射传输理论和大气微波气体吸收系数模型对星载高光谱微波辐射计探测亮温进行仿真,同时利用仿真数据建立并训练基于神经网络算法的反演模型。基于该平台对50~70 GHz氧气吸收带观测亮温和大气温度廓线反演结果进行分析,对比不同通道数情况下观测亮温、权重函数和反演统计误差结果。实验结果表明,高光谱微波辐射计对各气压层大气温度廓线遥感探测精度均有提升,尤其是对于高层大气温度廓线提升显著。

     

    Abstract: Compared with traditional radiometers, hyperspectral microwave radiometers have significantly increased the number of channels and can obtain continuous and high-frequency resolution brightness temperature detection results. However, due to issues such as channel correlation and reduced sensitivity after channel subdivision, further theoretical research is needed to support the improvement of hyperspectral microwave remote sensing capabilities. In view of issues above and the fact that there is no on-orbit hyperspectral microwave radiometer for Earth observation at present, a platform for brightness temperature simulation and atmospheric temperature profile retrieval analysis of spaceborne hyperspectral microwave radiometer is built. This platform simulates the brightness temperature detected by spaceborne hyperspectral microwave radiometer based on radiation transfer theory and atmospheric microwave gas absorption coefficient model, and constructs and trains an inversion model based on neural network algorithm using the simulated data. The brightness temperature observed in the oxygen absorption band of 50 GHz to 70 GHz and the retrieval results of atmospheric temperature profile are analyzed based on this platform, and the observation brightness temperature, weighting function and statistical errors of retrieval results under different channel numbers are compared. The experimental results show that the hyperspectral microwave radiometer can improve the remote sensing detection accuracy of atmospheric temperature profiles in various pressure layers, especially for the high-altitude atmospheric temperature profile.

     

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