针对PM_2.5污染比较严重的川渝地区，本研究利用日本静止葵花卫星（Himawari-8）反演的气溶胶光学厚度（AOD）进行垂直订正和湿度订正估算川渝地区2017年—2018年09：00—16：00时的PM_2.5浓度。首先，基于气象观测的能见度（vis）数据与消光系数σa(λ)之间的关系，引入“标高（Ha）”对气溶胶光学厚度进行垂直订正；其次，根据匹配的气象和环境监测数据对每一个站点逐一拟合1—12月份的吸湿增长因子，并采用反距离加权空间插值（IDW）方法构建吸湿订正因子网格，从而进行湿度订正估算。研究结果表明，经垂直订正和湿度订正后，相比AOD与PM_2.5之间的相关性，“干”消光系数σdry与PM_2.5的相关性显著提高，相关系数（r）由0.12—0.45提高至0.32—0.69；验证09：00至16：00时卫星估算结果，相关系数（r）均大于0.7，均方根误差（RMSE）为18.59±2.26 μg/m³；提取所有观测站点进行验证，r=0.82，RMSE=18.64 μg/m³。

Together with the sustained and rapid development of China’s economy in the past few years, the continuous improvement of the national economy, and the trend of urbanization, is the unceasing decline of China’s air quality. As a result, frequent occurrence of haze pollution weather has seriously affected people’s health. As the main pollutant of haze, PM_2.5 has become a major concern of all people. Studies have shown that people exposed to PM_2.5 for a long time are likely to suffer from respiratory and cardiovascular diseases, and even die prematurely. Therefore, it is of particular importance to monitor and evaluate PM_2.5 effectively and accurately. According to the requirements of national development, Sichuan Province and Chongqing City (hereinafter referred to as Sichuan and Chongqing Area) will work together to build a two-city economic circle in Chengdu-Chongqing Area. Therefore, it is urgent to study and evaluate the regional atmospheric environmental air quality. However, due to the unique topography and meteorological conditions in Sichuan and Chongqing, estimating the near-surface PM_2.5 concentration by using satellite remote sensing method is difficult. Considering the complicated topography in Sichuan and Chongqing Area, “Elevation (Ha)” was introduced for vertical correction of regional Aerosol Optical Depth. Moreover, considering the large difference of humidity and pollutant emission in different months, the hygroscopic correction factor grid was constructed for humidity correction by fitting the hygroscopic growth factor month by month and site by site. Therefore, first, the retrieval accuracy of AOD of Japanese geostationary Himawari satellite (Himawari-8) was verified in this study. Second, the vertical correction and humidity correction methods were used to estimate the hourly near-surface PM_2.5 concentration from 09:00 to 16:00 in 2017—2018 in the Sichuan-Chongqing Area, and the accuracy was verified. The area PM_2.5 concentration is helpful for the detailed analysis of pollutant generation, migration and dissipation hour by hour, which provides effective data support for regional pollution prevention and control. We arrive at the following conclusions: (1) Owing to the large differences in the hygroscopic growth characteristics of aerosol particles in different regions and time ranges, the four stations, namely, Ziyuan Station in Chengdu City, Rongxian Administrative Center Station in Zigong City, Shangqing Temple Station in Chongqing City, and Jingtan 2nd Road Station in Chongqing City, are selected to analyze the temporal and spatial differences in aerosol hygroscopic growth characteristics. Results show that the aerosol hygroscopic growth capacity of different sites in the same month is different. The aerosol hygroscopic growth capacity of the same site in different months is also different, and the relative humidity of different sites at different times changes greatly. Therefore, the hygroscopic correction factor grid constructed must be used by fitting the hygroscopic growth factor month by month and site by site during the humidity correction to estimate PM_2.5. (2) Compared with PM_2.5 and AOD, the correlation coefficient between PM_2.5 and σdry has significantly improved after vertical correction and humidity correction; it increased from 0.12—0.45 to 0.32—0.69. The correlation coefficient between the satellite estimated value and ground-based observation value is relatively high (r=0.82), and the RMSE is 18.64 μg/m³, which is a good estimation result. A comparison of the hourly and monthly scales shows that the estimation results from the afternoon are better than that from the morning, and that from autumn and winter are better than that from spring and summer. (3) According to the annual average spatial distribution of PM_2.5 in 2017 and 2018, the concentration of PM_2.5 in Sichuan and Chongqing Area is the highest in winter, lowest in summer, followed by that in spring and autumn. The vertical correction and humidity correction methods are used to estimate PM_2.5 mass concentration in Sichuan and Chongqing Area in 2017 and 2018, with high accuracy and good estimation results. However, the topography and aerosol components are not considered in the estimation process. Therefore, the experimental results still needs to be improved.