Journal Article

Exploring the Diurnal Dynamics Mechanism of the Cold Island Effect in Urban Parks of Island Cities: A Three-Dimensional Spatial Morphology Perspective

Li, Junyi, Ding, Guochang, Wang, Jingjing, Zhu, Zhipeng, Xu, Xiaoling, Wu, Yongshu, Fu, Weicong

2025

Overview

Urban parks play a crucial role in mitigating urban heat stress and maintaining ecological stability through their cold island effect (PCIE). However, studies examining how multidimensional urban morphology influences these effects, particularly from a diurnal perspective in island cities, remain limited. This study investigates 30 representative urban parks within a typical island city, exploring how two-dimensional and three-dimensional spatial morphological factors affect four key PCIE indicators: park cooling intensity (PCI), park cooling gradient (PCG), park cooling area (PCA) and park cooling efficiency (PCE) across different times of day and night. The results reveal that: (1) coastal zones exhibit significantly lower land surface temperature (LST) than inland zones, with peak LST occurring at 5:00 p.m.; (2) the four cold island indicators follow a diurnal pattern of 5:00 p.m. > 1:00 a.m. > 7:00 a.m.; (3) morphological construction factors—such as building density (BD) and built-up proportion (BP)—positively contribute to cooling effects at 7:00 a.m., while park perimeter (PP) enhances cooling performance at both 5:00 p.m. and 1:00 a.m. Additionally, vegetation characteristics surrounding parks, including the normalized difference vegetation index (NDVI) and green space proportion (GP), influence daytime cooling in directions opposite to those of the aforementioned construction-related factors. These findings offer valuable insights into the temporal dynamics and spatial determinants of urban park cooling in island cities, providing a scientific basis for scientifically informed park planning and contributing to healthier and more sustainable urban development.

• Publisher: MDPI AG
• Subject: Cities / Climate change / Coastal zone / Coastal zones / Cold / cold island effect / Construction / Cooling / Cooling effects / Distribution / Diurnal / Earth temperature / Environmental aspects / Environmental economics / Forecasts and trends / GDP / Green infrastructure / Gross Domestic Product / Heat stress / Heat tolerance / Influence / island city / Island effects / Land surface temperature / Measurement / Morphology / Normalized difference vegetative index / Parks & recreation areas / Pollution / Surface temperature / Sustainable development / Temperature / three-dimensional urban morphology / Urban areas / Urban development / urban green space planning / Urban heat islands / Urban parks / Urban planning / Urbanization / Vegetation / Vegetation index / Well being