Reconciling Debates on the Controls on Surface Urban Heat Island Intensity: Effects of Scale and Sampling.

Variations in the surface urban heat island intensity (SUHII) are regulated mainly by three types of control: surface property, background climate (or weather) conditions, and overall urban metric. However, intensive debates arise over the relative importance of these three control types. Here, over 896 Chinese city clusters, we reconcile these debates by showing that the priorities of the three SUHII control types depend closely on the scale and sampling criteria, although they are all crucial in regulating SUHII variations. With increasing temporal scale, the contributions from climate (or weather) conditions decrease, while those from surface property and overall urban metric increase. We find no consistent ranking in the relative importance of these three control types on various spatial scales. The sampling style of city cluster also contributes to disagreements regarding SUHII controls. Our findings potentially help resolve the long‐standing debate on the relative importance of SUHII controls. Plain Language Summary: Surface urban heat islands (SUHIs) have a profound impact on the lives of urban residents. Previous studies have suggested three major types of factors that control SUHI intensity (SUHII) variations: surface property, background climate (or weather) conditions, and overall urban metric. Debates however appear over the priorities of these three types of factors on regulating SUHIIs, and the lack of studies that can reconcile these debates has hindered significantly the in‐depth understanding of the SUHII mechanisms. Through an empirical analysis of the SUHII controls, our results show that these three types of factors are all indispensable in regulating the SUHII variations; and their priorities closely depend on the scale and sampling style. Furthermore, this study summarizes the types of factors that matter the most to the SUHIIs under different scenarios, and therefore has the potential to help develop the most efficient SUHI mitigation strategies. Key Points: Contributions from climate condition to surface urban heat island intensity (SUHII) gradually decrease with increasing temporal scaleNo common rank exists in the relative importance of main types of SUHII controls over different spatial scalesSampling style of city cluster by urban area or climate zone contributes to debates on ranks of SUHII controls [ABSTRACT FROM AUTHOR]