Three-dimensional landscape features impact on urban surface wind velocity during a heatwave: Relative contribution and marginal effect

Abstract

Accelerating the flow of surface air through urban areas at a faster rate is one of the important nature-based solutions for reducing the threat of urban overheating. Previous studies have focused on analyzing the correlation between two-dimensional landscape patterns and sky conditions. However, the relative contribution of three-dimensional (3D) landscape features to urban wind and the marginal effect during a heatwave remain unclear. In this study, the Weather Research and Forecasting (WRF) model was used to simulate the development of the wind field during heat events with weak synoptic wind. The regions were clustered based on land cover characteristics. The impact of 3D landscape features on the wind velocities in each cluster was further explored. Results revealed that ventilation corridors predominantly occurred in the morning, dissipating by midday. Diurnal wind velocities were primarily influenced by Forest Canopy Density (FCD), Building Congestion (BC), and Landscape Shape. Specifically, in suburban areas, the negative effect on surface wind velocities stabilized when BC exceeded 0.12. This phenomenon also occurred when the FCDs were higher than 0.75. Based on these findings, the study proposes urban planning strategies aimed at enhancing natural ventilation in cities, assisting planners in developing sustainable cities with cool winds.