面向城市场景的地表等效发射率方向性差异核驱动模型

提升城市地表温度遥感反演的精度正面临诸多困难，其中由于复杂的城市结构形态所引发反演温度的“角度效应”，日益成为主导限制因素。地表等效发射率的方向性差异研究被认为是解决角度效应问题的重要途径，而核驱动模型则为刻画等效发射率方向性差异提供了有效手段。项目针对不同城市场景，围绕地表等效发射率，旨在阐明其方向性差异的内在规律，构建其核驱动模型，进而发展城市地表遥感反演温度的角度效应消除方法。.研究内容包括：1）通过不同城市场景简化、模拟及生成，构建城市场景热辐射传输模型和几何光学模型，揭示等效发射率方向性差异的驱动机制；2）搭建核驱动模型理论框架，构建“核”的数学表达，厘定核驱动模型的适用范围和不确定性；3）耦合等效发射率方向性差异核驱动模型与“劈窗算法”，发展角度效应消除方法。以多角度静止轨道卫星与多时间极轨卫星相结合，构建城市地表遥感反演温度的角度效应消除模式，并开展角度效应消除的交叉验证。

Improving urban surface temperature inversion accuracy from remote sensing approach is facing many difficulties. The angular behavior of land surface temperature (LST) caused by heterogeneous urban surface structure is becoming a dominant limiting factor. Studies on the angular variation in effective emissivity are considered as an important way to address the angular effects and the kernel driven model shows its ability to quantify the directional effective emissivity. This project plans to construct urban scenes of different characteristics and describes the basic law that underlies the angular anisotropy from the perspective of effective emissivity. A kernel driven model will be developed to correct the angular effects of LST derived from remote sensing data. .This study includes the following: (1) We will construct a radiative transfer model and a geometric optical model to analyze driving kernels of directional effective emissivity through simplifying, simulating and generating different urban scenes. (2) We manage to construct a theoretical framework for the kernel driven model, elicit its mathematical forms and discuss its applicability and uncertainty. (3) We will propose an algorithm to address angular effects coupling the kernel driven model for effective emissivity anisotropy with the split window algorithm for retrieving directional-independent LST. A pattern to address urban surface temperature directional anisotropy will be proposed and cross-validated by using multi-angular data from geostationary satellites and multi-temporal data from polar orbiting satellites.