Satellite-based spatiotemporal analysis of urban park cooling efficiency: A decade-long shift from scale-driven to quality-driven dynamics in Zibo, China

The increasing incidence and severity of extreme heat events, attributable to global warming, constitute a substantial threat to urban areas. Despite the dearth of quantitative scholarship concerning the spatio-temporal coolness benefits of parks, the development of park cities is imperative for the transformation of industrial cities and for coping with high heat events. This study takes Zibo City as an example, which is a typical representative of the transformation of an old industrial city and a "whole-area park city." The study utilizes vector data and Landsat 8 satellite imagery from 2015 (90 parks), 2020 (105 parks), and 2025 (120 parks) to illustrate the dynamic features of the park cooling effect. The research investigates the effects of parks’ own features and the adjacent landscape on cooling efficiency, employing correlation analysis, Random Forest (RF) regression, and Boosted Regression Tree (BRT) methodologies. The results indicate that (1) by 2025, regions exceeding 40°C have diminished by 16%, attributable to an augmentation in the magnitude and extent of urban green spaces; and (2) during the period from 2015 to 2025, park cooling intensity increased from 0.48 to 0.75°C. Park maximum cooling intensity and park cumulative cooling intensity also grew simultaneously; (3) in the spatial dimension, the maximum cooling distance has been expanded from 300 meters to 330 meters. Park cooling area has significantly expanded, and park cooling efficiency is more suitable for small parks; (4) The roles of park green space configuration, surrounding green infrastructure, and the normalized difference vegetation index in enhancing cooling performance have progressively exceeded that of park area, indicating a shift from a “scale-driven” to a “quality-driven” paradigm. The research results are expected to reveal the ecological regulation mechanism of urban parks, providing a theoretical framework and empirical basis with regional characteristics and universal value for the climate-adaptive planning of high-density cities.