太赫兹波段冰云散射辐射的极化特征研究

冰云对全球气候变化研究以及预警侦察、精确制导等军事应用有重要影响，提高冰云微物理参数的测量准确性是大气遥感领域的前沿课题。太赫兹波与典型冰云粒子尺度处于同一量级，是理论上遥感冰云微物理参数的最佳波段，而太赫兹辐射计通道极化辐射的充分利用有助于提升冰云参数的测量精度。项目针对星载太赫兹辐射计通道测量辐射的极化特征进行研究，定量分析冰晶粒子形状、水平取向等属性对星载太赫兹辐射计极化特征的影响，明确冰云散射辐射极化特征的主要影响因素，开展极化通道的敏感性试验；在此基础上，建立通道辐射极化特征对反演结果的约束条件，构建融合极化特征的反演方法，并设计极化特征约束反演方案的有效性验证试验，形成闭合研究。项目的研究充分挖掘太赫兹辐射计极化测量的潜在应用，预期成果对于进一步提高冰云参数的反演精度具有重要意义，同时可为我国星载太赫兹辐射计的研制奠定理论和技术基础。

Ice clouds have a serious impact on global climate change research, early warning and reconnaissance system, precision guided weapon system and and other military applications. Improving the measurement accuracy of ice cloud microphysical parameters is a frontier topic in the field of atmospheric remote sensing. With terahertz wavelengths on the order of the size of typical cirrus cloud particles and therefore being sensitive to cirrus clouds, terahertz wave is expected to have a promising prospect concerning measuring cirrus microphysical parameters. The full utilization of the polarimetric radiation of the terahertz radiometer channels is helpful to improve the measurement accuracy of the ice cloud parameters. In this project, the polarimetric characteristics of spaceborne terahertz radiometer channels are studied. The influence of ice particle shapes, horizontal orientations and other characteristics on spaceborne terahertz polarization characteristics is quantitatively analyzed, and the main influencing factors of ice cloud scattering radiation polarimetric characteristics are identified. The sensitivity of polarization channels is carried out. On this basis, the approximate relationship between channel radiation polarimetric characteristics and inversion results is established. Based on the beam condition, the inversion method combining polarization characteristics is constructed, and the effectiveness verification test of the inversion scheme constrained by polarization characteristics is designed to form a closed loop study. The expected results are of great significance for further improving the retrieval accuracy of ice cloud parameters, and can lay a theoretical and technical foundation for the development of space borne terahertz radiometer in China.