Quantifying temperature reduction and expansion range of urban green spaces

Abstract

This study, grounded in policy promotion and practical land-use planning. The cooling effects of green spaces of different scales and types on surrounding microclimates were first assessed and then simplified into two key metrics. The first metric, Degree of cooling Effect (△T), quantifies the degree of cooling provided by green spaces, expressed as the difference between the reference air temperature at the outer boundary of each green space and the air temperature in its surrounding areas (°C). The second metric, Range of cooling Effect (RE), indicates the distance and extent over which green spaces exert measurable cooling on the surrounding microclimate. Interpolation techniques were subsequently applied to generate air temperature distribution maps, which were validated against results reported in previous studies. Based on these methods, a schematic urban cross-section of cooling effects was developed using Daan Forest Park as a representative case, providing a clear visual representation of the contributions of green spaces to microclimate cooling and supporting policy and practical planning applications. Since the primary analysis focused on park-square-type green spaces, this study further examines the cooling effects of greenways and tree-lined boulevards and explores alternative methods for evaluating the cooling performance of green spaces.