How urban expansion affects the thermal environment? A study of the impact of natural cities on the thermal field value and footprint of thermal environment

Urban expansion is an important factor affecting the urban thermal environment. Moreover, understanding how urban expansion affects the thermal environment, both inside and outside the region, can be effectively applied to urban planning and management. Therefore, we conducted a quantitative study on how urban expansion affects the thermal environment. We compared the changes in Natural cities (NCs) to understand urban expansion and used the thermal field value (TFV) (for assessing the thermal environment inside the region) and the thermal environment (TE FP) (for assessing the thermal environment outside the region) to represent the thermal environment. We found that urban expansion has a positive effect on the thermal environment both inside and outside NC. In addition, we confirmed that there was no correlation between the NC area and the mean TFV or the TE FP of the NC. Further, we found that in all 2020-NCs composed of a 2015-NC (O-NC) and a new expansion NC (E-NC), the mean TFV of the O-NC is higher than that of the E-NC. That is, there is a difference in the mean TFVs of the O-NC and the E-NC. Finally, we confirmed the proportion of the O-NC area as a factor affecting the mean TFV and TE FP of the NC.

Automated summary

Urban expansion has a positive impact on the thermal environment, both inside and outside Natural cities (NCs). The study shows that there is a difference in thermal field values between old and new urban areas within NCs, and the proportion of urban area contributes to the mean temperature field value and thermal environment outside the region.