资源环境科技发展态势分析平台

This paper presents the observed seasonal aerosol variations over Zhoushan, an eastern coastal Chinese city. Data were obtained from the Cloud - Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite from the period of June 2007 to May 2017. We compared the columnar Aerosol Optical Depth (AOD) data from the GAUPSO and MODerate resolution Imaging Spectroradiometer (MODIS). Results showed good consistency, but the former was systematically lower than the latter. The temporal distribution of columnar AOD showed significant variations with the highest in spring and lowest in summer. Similarly, the seasonal scatter plots suggested that the highest correlation coefficient was 0.56 in winter and summer, followed by the autumn (0.53), and spring (0.40) seasons. In addition, the results revealed that the polluted dust and polluted continental aerosols (38.9% and 30.5%, respectively) were dominant aerosol subtypes observed in winter, whereas, the polluted dust (47.2%) aerosol subtype was found dominant in spring. The polluted continental aerosol subtype appeared dominant during the summer and autumn seasons, with the frequencies of about 56.0% and 47.4%, respectively. These findings can be reasonably explained using the air mass cluster analysis computed for the obtained backward trajectories derived from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Furthermore, the aerosol vertical extinction coefficient measured at the wavelength of 532 nm was found to be highest near the surface (similar to 0.2 km(-1)) in winter and autumn and decreased sharply as the altitude increased indicating that aerosols were present at an altitude < 2 km. However, during spring, the values of extinction coefficient remained > 0.15 km(-1) at an altitude range of 0-3.5 km due to convection and strong vertical mixing lifting aerosols to slightly higher levels. Furthermore, during the spring, approximately 54% of the particulate depolarization ratio (PDR) values were <= 0.2, and the remaining 46% of the PDR were > 0.2, suggesting both spherical and irregular particles were present in the atmosphere.