Impact of spectral coupling between urban atmosphere and sky boundary conditions in a street canyon

• Published in: Journal of quantitative spectroscopy & radiative transfer Vol. 326; p. 109107
• Main Authors: Schmitt, Félix, Galtier, Mathieu, Merlier, Lucie, Vergnault, Etienne, André, Frédéric
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2024; Elsevier
• Subjects: Atmospheric and Oceanic Physics; Finite volume method; Mathematical Physics; Monte-Carlo; Participating medium; Physics; Radiative transfer; SLW model; Street canyon; Urban environment; Street canyon; SLW model; Urban environment; Monte-Carlo; Finite volume method; Radiative transfer; Participating medium
• ISSN: 0022-4073; 1879-1352
• DOI: 10.1016/j.jqsrt.2024.109107

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. •The interaction between radiation and the atmosphere is studied in a street canyon.•The strong spectral coupling between sky emission and air absorption is analyzed.•An efficient model (FVM-SLW) is proposed to accurately simulate these interactions.•A parametric study of wall fluxes with respect to street aspect ratio is carried out.