The urban weather generator

TLDR

Urban heat island effects raise air temperatures and are often ignored in building energy simulations, yet they can markedly influence energy use, especially in low‑heat‑gain or naturally ventilated buildings. The study introduces an urban weather generator that estimates canyon air temperatures from measurements at an open‑area weather station, enabling UHI effects to be incorporated into building energy models. The generator was calibrated and validated using field data from Basel, Switzerland, and Toulouse, France, demonstrating its applicability across different urban settings. Prediction errors remained within the natural temperature variability across urban canyon locations, indicating reliable performance.

Abstract

The increase in air temperature produced by urbanization, a phenomenon known as the urban heat island (UHI) effect, is often neglected in current building energy simulation practices. The UHI effect can have an impact on the energy consumption of buildings, especially those with low internal heat gains or with an inherent close interaction with the outdoor environment (e.g. naturally-ventilated buildings). This paper presents an urban weather generator (UWG) to calculate air temperatures inside urban canyons from measurements at an operational weather station located in an open area outside a city. The model can be used alone or integrated into existing programmes in order to account for the UHI effect in building energy simulations. The UWG is evaluated against field data from Basel (Switzerland) and Toulouse (France). The error of UWG predictions stays within the range of air temperature variability observed in different locations of the same urban area.