Page 194 - 《高原气象》2026年第1期

高 原 气 象 45 卷
190

Study on the Impact of Urbanization on Summer Heat Waves

in Yangtze River Delta

WU Yujia 1， 2， 3 ， LI Yarong ， HE Jianjun ， CHEN Liang 1， 2
3
3， 4
（1. Key Laboratory of Geographic Information Science（Ministry of Education）， East China Normal University， Shanghai 200241， China；
2. School of Geographic Sciences， East China Normal University， Shanghai 200241， China；
3. State Key Laboratory of Severe Weather Meteorological Science and Technology， Chinese Academy
of Meteorological Sciences， Beijing 100081， China；
4. College of Earth and Environmental Sciences， Lanzhou University， Lanzhou 730000， Gansu， China）

Abstract： Under the background of global climate warming and rapid urbanization， extreme heat events have be‐
come a significant threat to human health and social sustainable development， particularly in Yangtze River Delta
（YRD）， a densely populated and economically developed region. Based on meteorological observations from
1961 to 2020， this study systematically analyzes the trends of daily maximum temperature， daily mean tempera‐
ture， and heat wave indices in the YRD. Additionally， sensitivity experiments using the WRF model are conduct‐
ed to assess the impact of urban land use on extreme high temperature events. The results show that： （1） Both
daily maximum temperature and daily mean temperature in the YRD have exhibited significant upward trends
over the past few decades， with the increase in daily maximum temperature ［0. 194 ℃·（10a）］ being more pro‐
-1
-1
nounced than that in daily mean temperature ［0. 187 ℃·（10a）］. Pettitt test results indicate a significant change
point in 1993， with temperatures showing a downward trend before the change point and shifting to an upward
trend after the change point.（2） The frequency， duration， and intensity of heat waves have significantly in‐
-1
-1
creased at rates of 0. 190 time·（10a） ， 0. 475 d·（10a） and 0. 772 ℃·time ·（10a） ， respectively， indicating
-1
-1
that the frequency， duration and intensity of heat waves increased significantly. The change point for heat wave
indices lags behind that of temperature change point and occurring in 2000. It showed an insignificant downward
trend before the change point， and turning into a significant upward trend after the change. Intensity of heat wave
increasing at a much higher rate than frequency and duration.（3） Urbanization has a significant impact on tem‐
perature and heat waves. The daily maximum temperature ［0. 243 ℃·（10a）］ and daily mean temperature
-1
-1
-1
［0. 261 ℃·（10a）］ of urban stations being significantly higher than those of rural stations ［0. 171 ℃·（10a） 、
0. 167 ℃·（10a）］， suggesting that urbanization has an amplifying effect on warming. The increasing trends of
-1
heat wave indices at urban stations are also significantly stronger than those at rural stations， indicating that ur‐
banization may enhance the occurrence of heat waves.（4） The WRF model can effectively simulate the hourly
variation of temperature， and urban land use significantly affect urban station temperatures， especially during hot
days， with a more pronounced effect at night. Urban underlying surfaces enhance the surface energy changes of
urban stations during hot days by changing the surface energy budget （such as sensible heat flux， latent heat flux
and surface heat storage）， which intensifies the temperature during hot days， while rural stations are less affect‐
ed by urbanization. This indicates that the urbanization process has a more obvious impact on extreme high tem‐
perature events in urban areas. The frequency， intensity and duration of heat waves in the Yangtze River Delta re‐
gion have shown a significant upward trend in the past few decades， and urbanization has played an important
amplifying role in this. With the further development of urbanization， the frequency and intensity of extreme
high temperature events are likely to increase further， highlighting the necessity of developing effective adapta‐
tion strategies and mitigation measures.
Key words： WRF； urbanization； underlying surface； heat waves； Yangtze River Delta