气溶胶光学厚度和不透水地表覆盖度对城市热岛强度的影响——以关中地区为例

Abstract

城市热岛效应（UHI）是人们最为关注的城市生态环境热点问题之一，城市热岛及其影响因子的研究对生态城市建设具有重要意义。利用城市热岛足迹（UHI FP）、局部G^*指数、Pearson相关系数以及气溶胶定量归因分析法研究了气溶胶光学厚度（AOD）和不透水地表覆盖度（ISP）对城市热岛的影响。研究结果表明：在2000-2018年间，关中地区西安及咸阳（西咸）城区的白天/夜晚城市热岛足迹均有显著增加，城市热岛效应逐年增强。西咸白天/夜晚城市热岛足迹范围比宝鸡市大，城市热岛现象更为明显。西咸城区夜晚热岛足迹范围内被地表温度（LST）高值所占据，夜晚城市热岛效应比白天更明显。宝鸡市虽然热岛足迹范围增减幅度不大，但足迹内白天/夜晚LST次热区面积逐渐增大，城市热岛效应日趋增强。西咸、宝鸡市城区的夜晚城市热岛强度（ΔT）与不透水地表覆盖度呈显著正相关关系，与城乡气溶胶光学厚度之差（ΔAOD）呈明显负相关性。西咸城乡ΔAOD为负，对城市热岛强度的平均贡献度为（0.41±0.14）℃；宝鸡市城乡ΔAOD为正，其平均贡献度为（-0.26±0.25）℃。综上所述，城市不透水地表面积的扩张会使城市热岛效应进一步加剧，西咸与宝鸡市城区气溶胶浓度的增加会抑制城市热岛的形成，但综合其他因子的影响作用，西咸与宝鸡市城市热岛强度仍在逐年增加。;The urban heat island effect (UHI) is one of the hot issues of urban ecological environment that people are most concerned about. It is of great significance to explore urban heat island effect and its impact factors for the construction of eco-city development. In this paper, the effect of aerosol optical depth (AOD) and impervious surface percentage (ISP) on urban heat island was investigated via the urban heat island footprint (UHI FP), Getis-Ord G^*, Pearson correlation and AOD quantitative attribution analysis method. The results show that between 2000 and 2018, the day/night UHI FP in the urban area of Xi'an and Xianyang (Xixian) increased significantly and the influence of UHI was enhanced year by year. The day/night UHI FP of Xixian was wider than that of Baoji, and the UHI phenomenon of Xixian was more obvious. The UHI FP of Xixian at night was almost entirely dominated by the high land surface temperature (LST) value, and UHI at night was more obvious than during the day. Although Baoji's UHI FP did not increase or decrease significantly, the day/night LST sub-heat zone area within UHI FP of Baoji increased gradually, and UHI significantly increased. The impervious surface percentage in the urban area of Xixian, Baoji was significantly positively correlated with night urban island intensity (ΔT). The difference between urban and rural aerosol optical depth (ΔAOD) was also significantly negatively correlated with night ΔT. ΔAOD in the Xixian was negative, and the average contribution was (0.41±0.14) ℃. The ΔAOD of urban and rural values in Baoji were positive, and the average contribution was (-0.26±0.25) ℃. In general, the expansion of urban impervious surface will further worsen UHI, and the increase of AOD in the urban area will inhibit UHI formation. However, UHI intensity of Xixian and Baoji is still increasing year over year due to the comprehensive influence of other factors.