基于地球红外背景模拟的 水云大气影响初步分析

Preliminary Analysis of the Water-Cloud Atmosphere’s Effect Based on Earth-Background Infrared Simulation

摘要:

为支持地球红外背景的模拟研究,以天基观测为前提,计算了2个大气窗口下,4个具有典型大气和地表特 征的区域在水云大气下的路径透过率和各成分辐射亮度。通过相对变化比例,讨论了地球背景模拟中水云与地表 的图像区分以及地域的影响。结果表明,水云对地球背景辐射传输影响显著:云层下方辐射会被强烈衰减,同时观 测路径中的散射辐射大幅增强。在同一选定区域下,积云大气的观测路径亮度相对无云大气下变化最大,在相同 水云类型条件下,大气散射和太阳散射亮度在不同区域区别较大,说明在模拟水云地球背景时不能忽略地域的影 响。计算和分析结果可为地球背景模拟中的水云红外图像生成提供一定的数据基础和技术支持。

Abstract:

To improve the earth-background radiation model, path transmittance of water-cloud atmosphere and compo? nents of earth-background radiance in 4 target areas, based on real surface type and climate, were calculated. Through rel? ative change ratio, the identification of water-clouds IR picture and the influence of aerosol and atmospheric models over the solar and atmospheric scattered radiation were analyzed. The results showed that water-clouds exert significant influ? ence on the process. Radiance below the clouds were rapidly attenuated while the scattered radiance were greatly en? hanced. In the same area, cumulus causesd the biggest change to observing-path radiance. Besides, scattered radiance dif? fered respectively from each other in different areas, which proved aerosol and atmospheric model are indispensible factors for simulating water-clouds in earth-background radiance. The calculation and analysis results could provide data and technology support for generating water-clouds' IR picture in earth-background radiation simulation.