Temporal characteristics of urban heat island and its response to heat waves and energy consumption in the mountainous Chongqing, China

In this study, the time series of temperature in Chongqing, China, from 1979 to 2018 was statistically analyzed, and both the interdecadal and seasonal variation characteristics of urban heat island intensity (UHII) were studied. The results show that the temperature in Chongqing has risen significantly in the past 40 years and that the temperature of the Chongqing urban area is approximately 1.6 times higher than the global warming trend. During the study period, the annual average UHII at urban and rural stations increased significantly at a rate of +1.3 degrees C/century. The seasonal variation in the nighttime UHII was higher in summer, while the seasonal variation in the daytime UHII was higher in winter. In addition, the annual average UHII was found to be related to the heat wave (HW) days, cooling degree days (CDD), and heating degree days (HDD). With an increase of 1 degrees C in the UHII, the HW days in urban area increased by approximately 10 d, the average difference of the CDD increased by approximately 72 degrees C center dot d, and the average difference of the HDD decreased by approximately 86 degrees C center dot d.