Spatial pattern of anthropogenic heat flux in monocentric and polycentric cities: The case of Chengdu and Chongqing

• Anthropogenic heat flux (AHF) had spatial variations under distinct urban forms. • Building and traffic contributed more AHF than industry and human metabolism. • AHF pattern was contiguous in Chengdu and clustered in Chongqing. • High AHF gathered in Chengdu's center but dispersed in Chongqing's several centers. Although anthropogenic heat emission (AHE) has been acknowledged as a significant threat to urban thermal environment, little attention has been paid to the differences in the intensity of AHE, namely anthropogenic heat flux (AHF), under distinct urban forms. Therefore, we chose one monocentric city (Chengdu) and one polycentric city (Chongqing) in China to compare the spatial pattern of AHF. AHE was calculated from four aspects of buildings, traffic, industries, and human metabolism for the whole cities and then allocated to the blocks using the inventory-based method. The results showed that building and traffic heat accounted for major AHE. In Chengdu, annual mean AHF decreased from the urban core to the suburbs, forming a circular and contiguous pattern. In Chongqing, AHF concentrated in several hotspots of the (sub)centers, resulting in a balanced and clustered pattern. AHF from buildings and human metabolism were contiguous and concentrated within city centers. In contrast, AHF from traffic and industries were scattered and dispersed in line with the road networks and industrial patterns. The results reflected that the spatial pattern of AHF varied with different urban forms, which called for planners to consider the differences and make related policies to mitigate AHF for urban sustainability.