The Thermal Regulator Role of Urban Green Spaces: The Case of Coimbra (Portugal)

Abstract

Urban transformations, driven by human activities, result in unique urban ecosystems that significantly impact thermal environments. This study delves into the implications of anthropogenic climate change on diverse urban structures, aiming to enhance urban resilience. A key question arises: how do different urban structures affect the urban thermal environments at multiple scales? This study explores the relationship between urban morphology and temperature variations at both surface and vertical levels during different times of the day. Using data loggers and vertical temperature recordings through UAV, temperature data were collected on pre-established pedestrian pathways that cover different urban morphologies. The selection of the routes covered different densities of urbanized areas and green spaces. This facilitated the creation of a study examining the impact of both 2D and 3D urban green space structures on the thermal landscape of a Mediterranean city—Coimbra, Portugal. The gathered data provided insight into (1) the role of green spaces in the climatic regulation of the city, regardless of the time of the day; (2) the direct relation between surface temperatures and green space morphology; (3) the fact that green spaces act as a cell of fresh air, even in urban areas where there is a measurable urban heat island; (4) the fact that urban areas with green spaces with high tree density present great thermal inertia specific to each morphology in the first 30 m, whereas from 30 to 200 m all profiles present similarly; (5) urban areas with green spaces with high tree density show differentiated temperatures, both at the surface and at altitude. This research underscores the pivotal role of urban green spaces in city planning, emphasizing their importance for bolstering climate change resilience. Acknowledging the thermal regulation benefits offered by green spaces is imperative for aligning with sustainable development objectives in modern cities.