Environmental Influence on NbS (Nature-Based Solution) Mitigation of Diurnal Surface Urban Heat Islands (SUHI)

Utilizing 58 Landsat-7 images taken over 10 years, the current study investigated the relationship between the mitigation of surface urban heat islands (SUHIs) by NbSs (Nature-based Solutions) and influential variables such as physical variables of NbSs, environmental variables of the streets, and meteorological variables. Parks and permeable pavements are the two types of NbS devices under examination. Reference (i.e., unaffected by any NbS) and experimental (i.e., affected by only one NbS) areas were selected to perform the analysis. Areas affected by large water bodies or more than one NbS device were excluded. The cooling effect caused by NbS was linked to the influential variables by multiple regression models. Key findings included the following: Firstly, the distance to an NbS is more important than the area of an individual NbS, implying that small and evenly distributed NbS devices might have better overall cooling effects than large but sparsely placed NbS devices. Secondly, NbSs do not significantly contribute to cooling in districts with grid-type streets, while exhibiting significant cooling for districts with complex street patterns. Older districts with complex street patterns should be the focus of NbS implementation, not newer, modern districts. However, NbS cooling is sensitive to several variables in districts with complex patterns. NbS installation in those districts requires careful planning to maximize engineering investment. Lastly, maintenance can be essential to sustain the cooling capacity of NbSs over time.