Master Thesis Defense by Filomila Dimitra Avdi

Title: Assessing urbanization impacts on meteorology over Copenhagen using the Enviro-HIRLAM model: A focus on canopy-layer Urban Heat Island

Abstract:
This study investigates how urbanization and anthropogenic heat fluxes (AHF) affect near-surface urban climate in the Copenhagen Metropolitan Area using the Enviro-HIRLAM model. Local Climate Zones (LCZs) generated by the World Urban Database and Access Portal Tool (WUDAPT) were implemented in the model’s Building Effect Parametrization (BEP) scheme to provide a more realistic representation of urban morphology. An addition of anthropogenic heat fluxes of 23 and 57 W/m² was integrated for urban grid cells in the model simulations. A sensitivity study was conducted for 1-7 September 2010, to explore the effect of different land-use change and AHF scenarios on two meter temperature, canopy-layer urban heat island (UHI) detection, and surface heat fluxes.

The implemented land-use change alone increased mean nighttime urban 2 meter-temperature by up to 0.3^oC, while the addition of AHF intensified urban warming, reaching a difference of up to 1.1 ^oC on specific days compared to a simulation with no urban or AHF parametrization. Simulated UHI magnitude reached approximately 2.2 ^oC, with the AHF=57 W/m² scenario agreeing best with observations (RMSE = 0.53 ^oC). Its observed diurnal mean was captured adequately by all model simulations (r> 0.83). Urban sensible heat flux peaked sharply at midday and scaled with AHF, while latent heat flux remained near zero in the urban site, contrasting with reanalysis data. Rural sensible and latent heat fluxes showed close agreement between datasets. Overall, this study highlights the importance of developing a detailed and reliable urban climate modeling framework that can support adaptation and evidence-based urban planning in Copenhagen.

Supervisors: Alexander Baklanov, Jens Hesselbjer Christensen

Censor: Martin Drews DTU