地表发射率多时间尺度变化规律及遥感反演模型研究

发射率作为地表辐射过程的一个基础参数，是影响地表温度遥感反演精度最为直接的因子。然而，由于连续实测资料的限制，目前对不同时间尺度上发射率变化规律及其影响因子的认识还存在不足，缺乏深入考虑发射率变化规律的遥感反演模型，无法将发射率变化规律与地表温度遥感反演相联系。项目将以精确反演地表发射率为目标，以地表水热差异显著的西北地区为研究区，通过野外协同观测试验获得连续的发射率数据及对应的地表参数，研究典型植被和裸土下垫面发射率时空变化特征，揭示不同下垫面状况及地表过程对发射率的影响，确定不同时间尺度上影响发射率变化的关键因子，并通过参数化发射率变化规律建立考虑地表生物物理过程的遥感反演模型。该项目的完成不仅会对地表发射率的时空变化规律形成系统认识，提高发射率的反演精度，而且能够为地表温度反演精度的提高奠定基础。

Emissivity, as a basic parameter of land surface radiation process, is the most direct factor affecting the accuracy of land surface temperature retrieval. However, due to the limitation of continuous measured data, the understanding of emissivity variation law and its influencing factors on different time scales is still insufficient, and the remote sensing retrieval model considering emissivity variation law is lack, which cannot link emissivity variation law with land surface temperature retrieval. This project will take the emissivity accurate retrieval as the goal, take the Northwest China with significant difference in surface water and heat as the research area, obtain continuous emissivity data and corresponding land surface parameters through field collaborative observation experiment, study the temporal and spatial variation characteristics of emissivity for typical vegetation and bare soil underlying surface, reveal the influence of different underlying surface conditions and surface processes on emissivity, and determine the key factors that affect the emissivity change at different scales, and the remote sensing retrieval model considering the surface biophysical process is established by parameterizing the emissivity change law. The completion of this project will not only form a systematic understanding of the temporal and spatial variation for emissivity, improve the retrieval accuracy of emissivity, but also lay a foundation for the retrieval accuracy improvement of land surface temperature.