非均质场景热辐射方向性模型构建与应用研究

项目名称： 非均质场景热辐射方向性模型构建与应用研究

项目编号： No.41501366

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 天文学、地球科学

项目作者： 曹彪

作者单位： 中国科学院遥感与数字地球研究所

项目金额： 20万元

中文摘要： 热辐射方向性是制约当前地表温度产品精度提高及后续应用有效开展的瓶颈之一，地表温度产品及上行长波辐射产品的业务运行算法中均对该问题予以回避。现有的热辐射方向性模型多针对均质场景，对非均质场景刻画能力的欠缺在很大程度上限制了其在像元尺度上的应用。本项目尝试以植被、道路、房屋三种端元构成的典型非均质场景为例，提出可表征端元间邻接关系的空间异质性表达方法，探讨光子在端元内部及端元之间的辐射传输过程，构建考虑空间格局、三维结构和温度分布对热辐射影响的非均质场景热辐射方向性模型。在利用多尺度观测数据对模型进行验证的基础之上，尝试基于该模型深入分析方向辐射温度与半球辐射温度之间的差异。本项目有望成为链接热辐射方向性建模研究和地表温度反演研究的桥梁，有望进一步提高地表温度产品及上行长波辐射产品的精度。

中文关键词： 热辐射方向性；非均质场景；混合像元；地表温度；上行长波辐射

英文摘要： Thermal radiation directionality is one of the bottlenecks in the improvement of the accuracy of land surface temperature (LST) product and the applications of LST product. This problem has been ignored in the operational algorithms of LST product and upwelling longwave radiation (ULR) product. Most of current directional thermal radiation models are designed for homogeneous scene, and thus is not feasible for the heterogeneous scenes, especially at the satellite pixel scale. A typical heterogeneous scene composed of vegetation, road and house endmembers will be taken as an example, and a new spatial heterogeneity expression method will be proposed to characterize the adjacency relationship between different endmembers. Based on the understanding of photon radiative transfer process within and among different endmembers, we intend to build a new directional thermal radiation model for typical heterogeneous scene which can consider the effect of spatial pattern, three dimensional structure and temperature distribution. After validating the new model using multi-scale observations, we attempt to analyze the error of ULR when using directional radiation temperature as input, and analyze the feasibility of the validation method which uses longwave radiation observations as input. This project is expected to become the bridge linking the research of thermal radiation directionality modeling and the research of LST retrieval. And the new model is expected to improve the accuracy of LST and ULR products.

英文关键词： thermal radiation directionality;heterogeneous scene;mixed pixel;land surface temperature;upwelling longwave radiation