Key Laboratory of Regional Ecology and Environmental Change, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China; Hunan Key Laboratory of Remote Sensing of Ecological Environment in Dongting Lake Area, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China.
Key Laboratory of Regional Ecology and Environmental Change, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China; Hunan Key Laboratory of Remote Sensing of Ecological Environment in Dongting Lake Area, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China.
Sci Total Environ. 2021 Jun 10;772:145607. doi: 10.1016/j.scitotenv.2021.145607. Epub 2021 Feb 4.
The canopy layer urban heat island (CLUHI) and surface urban heat island (SUHI) refer to higher canopy layer and land surface temperatures in urban areas than in rural areas, respectively. The long-term trends of CLUHIs are poorly understood at the regional scale. In this study, 1 km resolution air temperature (Ta) data for the 2001-2018 period in the mainland of China were mapped using satellite data and station-based Ta data. Subsequently, the temporal trends of the CLUHI and SUHI intensities (CLUHII and SUHII, respectively) were investigated in 272 cities in the mainland of China. The Ta was estimated with high accuracy, with a root mean square error ranging from 0.370 °C to 0.592 °C. The CLUHII and SUHII increased significantly in over half of the cities in spring and summer, over one-third of the cities in autumn, and over one-fifth of the cities in winter. The trends of the nighttime SUHII were strongly related to the CLUHII calculated using mean and minimum Ta (correlation coefficients ranging from 0.613 to 0.770), whereas the relationships between the trends of the daytime SUHII and CLUHII were relatively weak. Human activities were the major driving forces for the increase in the CLUHII and SUHII. The difference in impervious surfaces between urban and rural areas was significantly correlated with the CLUHII and SUHII in approximately half of the cities. Meteorological factors were significantly correlated with the CLUHII and SUHII in few cities. This study highlights the trends of the significant increase in the CLUHII and SUHII in the mainland of China, which may have negative effects on humans and the environment.
林冠层城市热岛（CLUHI）和地表城市热岛（SUHI）分别指城市地区的林冠层和地表温度高于农村地区。在区域尺度上，人们对 CLUHI 的长期趋势知之甚少。本研究利用卫星数据和基于站点的 Ta 数据，绘制了中国大陆 2001-2018 年期间 1km 分辨率的空气温度（Ta）数据。随后，在中国大陆的 272 个城市中，研究了 CLUHI 和 SUHI 强度（分别为 CLUHII 和 SUHII）的时间趋势。Ta 的估计具有很高的精度，均方根误差范围在 0.370°C 到 0.592°C 之间。在春、夏两季，超过一半的城市，秋、冬两季超过三分之一的城市，Ta 均呈现出显著增加。夜间 SUHII 的趋势与使用平均和最小 Ta 计算的 CLUHII 密切相关（相关系数范围在 0.613 到 0.770 之间），而白天 SUHII 趋势与 CLUHII 之间的关系则相对较弱。人类活动是 CLUHII 和 SUHII 增加的主要驱动因素。城市和农村之间不透水面的差异与大约一半城市的 CLUHII 和 SUHII 显著相关。气象因素与 CLUHII 和 SUHII 在少数城市显著相关。本研究强调了中国大陆 CLUHII 和 SUHII 显著增加的趋势，这可能对人类和环境产生负面影响。
