Most radiative transfer models developed for the analysis of urban configurations consider a transparent urban atmosphere and gray sky conditions. The aim of the present work is to investigate these assumptions, focusing on the longwave domain. For this purpose, reference Line-by-Line Monte-Carlo calculations are first performed. A more efficient radiative transfer model based on the Finite Volume Method and SLW modeling is also developed to treat several street canyon configurations. The aspect ratio of the street canyon, a parameter frequently encountered in urban scenarios, is considered for the analysis. It is shown that, in most cases, real urban problems need to take into account a non-gray participating atmosphere within the streets, together with its spectral coupling with the non-gray sky downward radiation, to provide accurate net fluxes on urban surfaces and volumetric radiative powers in the urban atmosphere.

中文翻译：

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街道峡谷中城市大气与天空边界条件之间光谱耦合的影响


大多数为分析城市配置而开发的辐射传输模型都考虑透明的城市大气和灰色的天空条件。目前工作的目的是研究这些假设，重点关注长波域。为此，首先执行参考逐行蒙特卡罗计算。还开发了基于有限体积法和 SLW 建模的更有效的辐射传输模型来处理几种街道峡谷配​​置。街道峡谷的纵横比是城市场景中经常遇到的参数，在分析时考虑了这一参数。结果表明，在大多数情况下，真正的城市问题需要考虑街道内的非灰色参与大气，及其与非灰色天空向下辐射的光谱耦合，以提供城市表面的准确净通量和城市大气中的体积辐射功率。