Multi-scale effects of LCZ and urban green infrastructure on diurnal land surface temperature dynamics

Abstract

The impact of urban green infrastructure (UGI) on land surface temperature (LST) has been widely discussed as a strategy to improve urban thermal environments. However, most studies have focused primarily on daytime conditions. Due to the limitations of polar-orbiting satellites like the Landsat series, the influence of UGI on LST over a 24-hour cycle remains unclear. To assess the relative influence and interdependence of UGI characteristics on LST across four different grid scales over the diurnal cycle, this study, conducted within Beijing's Fifth Ring Road during the summer, utilized a random forest (RF) regression model. The results indicate that: (1) UGI's impact on LST follows two distinct patterns: daytime (morning and afternoon) and non-daytime (night and dawn), which indicates the intensity of sunlight as a key driving factor; (2) tree landscape pattern indices are the most significant factors affecting LST; (3) during non-daytime periods (night and dawn), cropland's cooling effect is equally important as that of trees. These findings are valuable for prioritizing and strategically placing different types of UGI in urban planning. However, as this study focuses on a specific area, future research should include comparative studies in cities with different climatic conditions.