Enhanced Cooling Efficiency of Urban Trees on Hotter Summer Days in 70 Cities of China  

作　　者：Limei YANG Jun GE Yipeng CAO Yu LIU Xing LUO Shiyao WANG Weidong GUO 

机构地区：[1]School of Atmospheric Sciences,Nanjing University,Nanjing 210023,China [2]Joint International Research Laboratory of Atmospheric and Earth System Sciences,Nanjing University,Nanjing 210023,China [3]Frontiers Science Center for Critical Earth Material Cycling,Nanjing University,Nanjing 210023,China

出　　处：《Advances in Atmospheric Sciences》2024年第11期2259-2275,共17页大气科学进展（英文版）

基　　金：supported by the Natural Science Foundation of Jiangsu Province (Grant No. BK20240170);Open fund by Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control (KHK2203);the Jiangsu Meteorological Bureau Youth Fund (KQ202314);the Fundamental Research Funds for the Central Universities (2024300330);Jiangsu Collaborative Innovation Center for Climate Change。

摘　　要：Increasing the urban tree cover percentage(TCP) is widely recognized as an efficient way to mitigate the urban heat island effect. The cooling efficiency of urban trees can be either enhanced or attenuated on hotter days, depending on the physiological response of urban trees to rising ambient temperature. However, the response of urban trees' cooling efficiency to rising urban temperature remains poorly quantified for China's cities. In this study, we quantify the response of urban trees' cooling efficiency to rising urban temperature at noontime [~1330 LT(local time), LT=UTC+8] in 17summers(June, July, and August) from 2003–19 in 70 economically developed cities of China based on satellite observations. The results show that urban trees have stronger cooling efficiency with increasing temperature, suggesting additional cooling benefits provided by urban trees on hotter days. The enhanced cooling efficiency values of urban trees range from 0.002 to 0.055℃ %-1 per 1℃ increase in temperature across the selected cities, with larger values for the lowTCP-level cities. The response is also regulated by background temperature and precipitation, as the additional cooling benefit tends to be larger in warmer and wetter cities at the same TCP level. The positive response of urban trees' cooling efficiency to rising urban temperature is explained mainly by the stronger evapotranspiration of urban trees on hotter days.These results have important implications for alleviating urban heat risk by utilizing urban trees, particularly considering that extreme hot days are becoming more frequent in cities under global warming.

关 键 词：urban trees cooling efficiency China's cities EVAPOTRANSPIRATION SUMMER hot days 

分 类 号：P423[天文地球—大气科学及气象学] X16[环境科学与工程—环境科学]