MLUCM BEP+BEM: An offline one-dimensional Multi-Layer Urban Canopy Model based on the BEP+BEM Scheme

Abstract. The MLUCM BEP+BEM model introduces key innovations in urban microclimate modelling, combining advanced turbulent diffusion schemes with Building Effect Parameterization (BEP) and a Building Energy Model (BEM). Key features include updated turbulent length scales and eddy coefficients accounting for atmospheric stability, as well as the integration of urban vegetation, such as green areas and street trees. This model can be run offline with low computational costs, making it ideal for standalone use, coupling with climate projections, and suitable for running long-term simulations to assess the impacts of different emission scenarios on the urban environment. Validation against data from the Urban-PLUMBER project at a suburban site in Preston (Melbourne, Australia) demonstrates a highly accurate reproduction of shortwave (SW_up), longwave (LW_up) radiation and an accurate reproduction of sensible heat (Q_h) and momentum (Q_tau) fluxes, highlighting the robustness of the model in complex urban environments. Further investigations are required to understand the causes of the unsatisfactory agreement between observed and modelled latent heat flux (Q_le). The versatility of the MLUCM BEP+BEM model enables its application across various climate scenarios for analysing the impact of climate change on urban overheating, energy demands, and for evaluating the effectiveness of strategies like green roofs, cool roofs, and photovoltaic panels.