粤港澳大湾区气溶胶对白天城市热岛强度的影响

以粤港澳大湾区为例，利用卫星遥感资料结合大气化学模式模拟，分析2003―2018年城市热岛强度、气溶胶光学厚度的变化规律，定性和定量研究气溶胶对白天城市热岛强度的影响。结果表明：2003―2018年粤港澳大湾区城市热岛强度呈波动上升趋势，夏季热岛强度最大，冬季热岛强度最小；气溶胶光学厚度呈波动下降趋势，春季气溶胶光学厚度最大，冬季气溶胶光学厚度最小。在年际和季节尺度，城市热岛强度与城区、郊区气溶胶光学厚度之差均呈弱的正相关。基于WRF-Chem的模拟实验表明，气溶胶的存在导致城区、郊区地表向下总辐射减少、地表温度降低，且城区地表向下总辐射减少多于郊区、降温幅度大于郊区，进而导致了热岛强度减弱。气溶胶对城市热岛强度的贡献率为?2.187%，冬季贡献率绝对值略高于夏季。

The Impact of Aerosols on Daytime Urban Heat Island Intensity in Guangdong-Hong Kong-Macao Greater Bay Area

Both of urban heat island effect and particulate pollution are hot social issues during the construction of Guangdong-Hong Kong-Macao Greater Bay Area. Taking Guangdong-Hong Kong-Macao Greater Bay Area as an example, the article analyzed change rules of urban heat island intensity (UHII) and aerosol optical depth (AOD), and the relationship between them based on satellite remote sensing data from 2003 to 2018. Then the change of UHII with the presence and absence of aerosols were simulated based on WRF-Chem, and the influence of aerosols on UHII in daytime was quantitatively studied. The results showed that UHII in Guangdong-Hong Kong -Macao Bay area fluctuated upwardly in the past 16 years, with the seasonal maximum in summer, and the seasonal minimum in winter. The maximum months were June and July, and the minimum month was February. The AOD fluctuated downwardly in the past 16 years, with the seasonal maximum in spring and the seasonal minimum in winter. The maximum month was April, and the minimum month was November. There was a weak positive correlation between UHII and difference of AOD between urban areas and rural areas on the interannual and seasonal scales. The simulation experiments based on WRF-Chem showed that the existence of aerosols led to the decreases of downward total radiation at ground surface and land surface temperature in urban and rural areas. Because the decrease of downward total radiation at ground surface in urban areas was more than that in rural areas, the cooling effect was greater than that in rural areas, which led to the weakening of UHII. The contribution percentage of aerosols to UHII was ?2.187%, and the absolute value of contribution percentage in winter was slightly higher than that in summer.