Quantifying the Contribution of Urbanization to Summer Extreme High-Temperature Events in the Beijing-Tianjin-Hebei Urban Agglomeration

Determining the contribution of urbanization to extreme high-temperature events is essential to the coordinated development of Beijing, Tianjin, and Hebei (BTH). Based on the dynamic data of land-use change in every 5 years, this study uses the coupled WRF-Building Effect Parameterization/Building Energy Model (BEP/BEM) at 1-km grid spacing to quantify the contribution of BTH urbanization to the intensity and frequency of hourly extreme high-temperature events in summer. From 1990 to 2015, extreme events over Beijing and its south increased by similar to 1.5 degrees-2 degrees C in intensity and by 50-100 h in frequency, both of which were even higher in central Beijing and Shijiazhuang. The increases of multiyear average urbanization contribution ratios to the intensity and frequency reached 3.3% and 51.6% at the 99% confidence level (p < 0.01) from 1990 to 2015, respectively. The corresponding contributions increased 1.8 and 1.2 times more significantly in the megacities (i.e., Beijing, Tianjin, and Shijiazhuang) than small and medium-sized cities. Therefore, the rapid urbanization has substantially enhanced the extreme high-temperature events in BTH. It is necessary to limit the urbanization growth rate and implement effective adaptation and mitigation strategies to sustain BTH development.

Automated summary

This study quantifies the contribution of urbanization to extreme high-temperature events in Beijing, Tianjin, and Hebei. The research finds that urbanization has significantly increased the intensity and frequency of these events, especially in larger cities. Therefore, it is crucial to limit the rate of urbanization and implement effective strategies for adaptation and mitigation in order to sustain development.