区域气候背景对城市热岛效应的影响规律

城市热岛效应受到区域气候背景的影响而具有显著的时空差异性，尚缺少大尺度对比研究。利用1991-2019年的月均气象数据，量化了我国69个典型城市的大气城市热岛效应强度，从热带、干带、暖温带、冷温带和极地带五个气候带，分析城市热岛效应的时空特征规律。结果表明：（1）区域差异：干带热岛效应明显高于其他气候带，极地带最弱，且表现为较强的冷岛效应，热带、暖温带、冷温带热岛效应较弱，而冷温带的京津冀地区由于城市化程度较高，表现出较强的热岛效应，温暖带中西南地区较为明显；（2）季节性差异：不同季节城市热岛效应的强弱关系在不同气候带有所不同，秋季热岛效应较为稳定，热岛和冷岛效应均主要处于弱强度范围，春、冬热岛效应较为波动，易出现强热岛、强冷岛效应的极端现象，夏季热岛效应发生率最高；（3）时间演变规律：城市热岛效应的多年演变规律在相同气候带较为一致，2010年前后是各气候带各季节城市热岛效应的变化拐点，2010年后，干带、冷温带、暖温带热岛效应均有所下降，热带、极地带有所上升。

Impacts of regional climate on urban heat islands in China

Urban heat island (UHI) has significantly temporal and spatial differences because of the impacts of regional climate background, and large-scale comparative studies are still lacking. Using the monthly average meteorological data from 1991 to 2019, we quantified the air UHI intensity of 69 typical cities in China, and the spatial and temporal characteristics of UHI were analyzed from five climatic zones, namely Equatorial climate, Arid climate, Warm temperate climate, Snow climate and Polar climate. The results show that: (1) Regional differences: the UHI in the Arid climate is significantly higher than that in other climatic zones, and the Polar climate is the weakest, even showing stronger urban cold island (UCI). The UHI in the Equatorial climate, Warm temperate climate, Snow climate are weaker, among of them, which is more obvious in the Beijing-Tianjin-Hebei region because of the high degree of urbanization in snow climate, and more obvious in the southwest in Warm temperate climate. (2) Seasonal differences: the strong and weak relations of UHI in different seasons vary with different climatic zones. However, nationwide, the UHI of all cities are relatively stable in autumn, both the UHI and UCI are mainly in the range of weak intensity. In spring and winter, the UHI is relatively fluctuant, prone to extreme phenomena such as strong UHI and strong UCI. The incidence of summer UHI is the highest, but its intensity is relatively weaker.(3) Time evolution: the variations of UHI in all seasons show a significantly uniform trend year by year in each climatic zone. Around 2010 is the inflection point of the UHI in all climate zones in all seasons. After 2010, the UHI has decreased in Arid climate, Warm temperate climate, Snow climate, while that in Equatorial climate and Polar climate has increased.