Surface urban heat islands in 932 urban region agglomerations in China during the morning and before midnight: spatial-temporal changes, drivers, and simulation

Abstract

Research was insufficient on the surface urban heat islands (SUHIs) in China during the morning and before midnight. Therefore, we studied the spatio-temporal variations and ten determinants of SUHI intensities (SUHIIs) at ∼10:30 am and ∼10:30 pm of 932 urban region agglomerations in the five ecological regions in China and further simulate these SUHIIs using the machine learning algorithm. The main findings were as follows. (1) The daytime SUHIIs in all regions were largest in the summer, and when the humid regions had higher SUHIIs than other regions. The maximum SUHIIs were usually significantly positively correlated with the minimum ones. (2) The SUHIIs were significantly partially correlated with the enhanced vegetation index, nighttime light intensity, PM_2.5, albedo, population density, precipitation, urban area size and landscape shape index in many or a few cases. (3) The root-mean-square errors of simulated daytime and nighttime SUHIIs were mostly less than 1.22 and 2.00 °C, respectively.

Keywords:

• Urban thermal environment
• land surface temperature
• remote sensing
• general regression neural network
• influencing factors

Data availability

The data in this study are available from the corresponding author upon request.

Disclosure statement

The authors have no relevant financial or non-financial interests to disclose.

Additional information

Funding

This research was funded by the Natural Science Foundation of China (Grant No. 41901235), Key Scientific Research Project of Universities and Colleges of Henan Province (Grant No. 21A170005), Henan Provincial Youth Natural Science Foundation (Grant No. 212300410103), Key Scientific and Technological Research Projects of Henan Province (Grant No. 212102310005 & No.192102310274), Key Scientific and Technological Project of Education Department of Henan Province (Grant No. 202102310337).