基于AERONET的中国地区典型站点气溶胶类型变化特征

基于AERONET网站中多个站点2006~2018年的观测数据，利用气溶胶光学厚度和气溶胶相对光学厚度，对中国华北北京、华东太湖、华南香港、西北SACOL多个站点的气溶胶进行分类，研究了中国地区典型站点气溶胶类型的时空变化特征.结果表明，我国华北、华南、华东区域站点以大陆型和城市工业型气溶胶为主，西北区域站点以大陆型气溶胶为主.气溶胶类型占比存在明显的年际变化，我国华北、华东区域站点大陆型气溶胶占比总体呈上升趋势，次大陆型溶胶占比呈下降趋势，其中华东区域站点年际变化较为突出，大陆型气溶胶占比年均上升2.78%，城市工业型气溶胶占比年均下降1.86%；华南区域站点大陆型气溶胶占比年均上升0.78%，且城市工业型气溶胶占比年均下降0.66%；而西北区域作为沙尘的主要源区，沙尘气溶胶变化最为显著，占比年均上升0.51%.我国不同区域气溶胶类型季节变化差异较大，春季华北、华东、西北区域均出现沙尘气溶胶，且西北区域尤为突出（占比19%）；华北区域城市工业型和大陆型气溶胶占比分别在夏、冬两季出现大值，华东区域城市工业型气溶胶在夏、秋两季占比较高，华南区域城市工业型气溶胶在春季占比最多（57%），西北区域大陆型气溶胶在夏、秋两季占比高达83%.

The spatiotemporal variations of aerosol types in representative sites of China basing on the Aerosol Robotic Network (AERONET)

Basing on the aerosol optical depth (AOD) and aerosol relative optical depth (AROD), retrieved from the Aerosol Robotic Network (AERONET) sites in China from 2006 to 2018, we classified the aerosol types and studied its spatiotemporal variations at the sites including Beijing, Taihu, Hong Kong and SACOL, representative of North China, East China, South China and Northwest China, respectively. The continental and urban industry aerosols were the dominant types of aerosols in the North, South and East China. The continental aerosols was the dominant aerosol type in Northwest China. The ratio of different aerosol types to the total aerosol existed distinct interannual variation in each region. Our results showed that the continental aerosols increased while sub-continental aerosols decreased during the past decade in North China, and especially in East China, where the clean continental aerosols' proportion rose at the rate of 2.78% per year, and the proportion of the urban industry aerosols dropped by 1.86% per year. On the other hand, the proportion of continental aerosol grew by 0.78% and urban industrial aerosol fell by 0.66% annually in South China. As the main source area of dust emission, the proportion of dust aerosols changed significantly in Northwest China, with an average annual increase of 0.51%. The seasonal variations of aerosol types were also found to be large in different areas. Dust aerosols occurred frequently during spring in North China, East China and Northwest China, and the percentage of dust in the latter was much higher than the other two regions (19%). The proportions of the urban industrial aerosols and continental aerosols in North China showed the highest values in summer and winter, respectively. The ratio of the urban industry aerosol in East China was substantial in summer and autumn, but the highest ratio of the urban industry aerosol in South China occurred in spring with the value of 57%. As for the Northwest China, the proportion of the continental aerosol was the highest in summer and autumn (83%).