Characterization of Aerosol-type Dependent Vertical Distributions in Relation to Convective Cloud Using Long-term A-train Satellite Observations

Aerosol vertical distribution is a significant contributor to uncertainties in aerosol forcing estimation, impacting the micro- and macrophysics of convective clouds, as the cloud-aerosol-radiation interaction largely depends on the relative position of aerosol layers with respect to clouds. However, a comprehensive understanding of the characteristics of aerosol vertical distribution and its dependence on aerosol types at a long-term and large scale remains elusive, especially from an observational perspective. In this study, we integrate 11 years of CALIPSO and CloudSat satellite measurements (2007-2017) to investigate aerosol vertical distribution in relation to convective clouds over East Asia, a region characterized by diverse aerosol emission sources and significant aerosol pollution variations. We identify four primary groups of aerosol vertical distribution patterns in East Asia, including “Bottom”, “Middle”, “Top”, and “Random”. Specifically, the Bottom group is characterized by aerosol layers mainly existing near the surface and below the cloud level, while the Middle and Top groups exhibit aerosol layers mainly around and above the cloud level, respectively. In the Random type, aerosols are randomly distributed throughout the tropospheric column. Notably, the Bottom and Random groups dominate the total aerosol-cloud collocation cases, with each accounting for more than 30% of the observations. Moreover, we observe clear variations of seasonal distributions for the Bottom and Top groups, with the Bottom group being more prevalent in summer and fall, and the Top group showing maximum occurrence in spring. The variations of aerosol types across aerosol vertical distribution are examined based on the aerosol type information from CALIPSO detections. The results demonstrate that the aerosol type seasonal distributions are closely linked to aerosol vertical distributions. For example, in the Bottom group, polluted dust, polluted continental, and clean marine aerosols are the most frequent types, with occurrences varying by season. Elevated smoke is more frequently detected in the Top group, while both elevated smoke and polluted dust dominate in the Middle group. In the Random group, clean marine aerosols are prominent. The long-term and large-scale observational perspective will provide comprehensive information on the aerosol vertical distribution associated with convective clouds over East Asia, which can be utilized to assess aerosol-cloud interactions more precisely.