Urban areas are prone to extremely high temperatures as a result of climate change and the urban heat island effect. Urban micro-climate modelling has become an important tool to evaluate the effect of heat mitigating measures and develop climate-sensitive urban designs. However, many models lack the accurate fine scale simulation of evapotranspiration influence and soil moisture conditions to predict human thermal comfort (HTC).
This works objective is to better understand the coupling of the heat and water balance for micro-climate predictions of urban squares and its influence on the HTC, especially under the influence of greening. Therefore, a literature review on recent model developments was conducted. Additionally, a case study was performed for the Heat Square in the Green Village using the model VTUF-3D, chosen based on the literature review.
Five urban micro-climate models work on the fine scale water balance representation, namely ENVI-met, i-Tree Hydro+, Solene-Microclimat, ST, and VTUF-3D. ENVI-met offers comprehensive analysis options of greening solutions and user-friendliness, while VTUF-3D excels in detailing soil and plant characteristics. Given the detailed water balance simulation and the accurate trend prediction for the latent heat flux, it is expected that greening effects on the urban micro-climate of the Heat Square can be predicted accurately with VTUF-3D, if not for spatial and human thermal comfort assessment.
The reviewed models require further model development towards a comprehensive water balance representation and related greening analysis options. Additionally, further efforts towards model applicability are needed, including validation and user-friendliness. VTUF-3D requires improvement of spatial variability representation and HTC prediction.
Note, the literature review is no holistic assessment and does not provide a conclusion on the overall performance of the models. The case study was limited in model feature configuration.