Regression Analysis of the Relationship between Urban Heat Island Effect and Urban Canopy Characteristics in a Mountainous City, Chongqing

Abstract

In order to guide the urban planning of thermal environment in a mountainous city, this paper reports a study which investigated the impact of four canopy characteristics: impermeable rate (IR), building density (BD), water body percentage (WBP) and planting rate (PR), on the average ambient air temperature (AAT) within seven built-up areas in the metropolitan city of Chongqing. A rural area was also monitored as a control for the investigation. Oziexplorer was used to measure the IR, BD, WP and PR within a radius of 100 m to 500 m of the locations investigated. Univariate linear regression was used to determine the correlation degree (CD) between each canopy characteristics and AAT. Different trends were observed and this correlated with the increasing radius of different sites. The maximum correlation coefficient between IR and AAT was observed within a 100-m radius of the investigated site. It was found that with an increase of radius, the influence of IR on AAT became weaker. The influence of BD on AAT became more significant and reached a maximum within 250 m radius. The multivariate linear regression analysis has illustrated the order of importance of canopy characteristics as: IR > WBP > PR > BD on daily mean air temperature within a 100-m radius of the locations investigated in Shapingba, Chongqing.