中红外大气辐射传输解析模型及遥感成像模拟

Mid-Infrared Atmosphere Radiation Transfer Analytic Model and Remote Sensing Images Simulation

为了建立完整的星载高分辨率中红外成像模拟系统,并为航天器载荷设计等相关工作提供有力参考,需要对大气辐射传输这一环节进行重点考虑,设计出切实可行,精度较高的大气辐射传输数值成像模拟方法。针对中红外大气辐射传输具有大气散射和自身发射的特性,将整个大气辐射传输过程进行了合理分解,并利用MODTRAN4对各辐射分量进行求解,以查找表方式实现了大气辐射传输成像模拟。此外,针对大气散射导致的邻近效应进行了分析,将原有PSF模型扩展至中红外波段,并与大气辐射传输解析模型相互耦合共同完成模拟成像。最后对模型进行了初步验证和成像模拟,结果表明:模型具有较好的模拟精度,通过给定观测几何和大气条件,并根据地表输入的温度和发射率等,实现逐像元的大气辐射传输计算。

In order to establish a complete set of simulation system for high-resolution mid-infrared remote sensing and provide a powerful reference for spacecraft design and related works, the importance of atmospheric radiative transfer simulation in this system was considered, and a reasonable and high precision imaging numerical simulation method was expected. Taking into account the characteristics of MIR, including scattering and thermal emission, terms of atmospheric radiative transfer were decomposed based on radiative transfer principle, and images of,top of atmosphere （TOA） were simulated according to MODTRAN4 and look-up table method. Besides, adjacency effect caused by atmospheric scattering of neighboring pixels radiation was considered, and an extended point spread function in mid-infrared was coupled with analytical model of atmospheric radiative transfer to simulate TOA images. Finally, a preliminary test and simulation results show that the simulation model has better accuracy. If parameters of observation geometry and atmosphere were given and the land surface temperature/emissivity was determined, the calculation of pixel-level atmospheric radiative transfer was to be achieved.