Characterization of a huge transatlantic smoke transport event by constructing an Aeolus smoke dataset in synergy with multi-platform data

Abstract. During the wildfire season on the West Coast of the US in September 2020, biomass burning smoke aerosol was continually generated, and several transatlantic smoke transports occurred. The ALADIN lidar onboard Aeolus satellite measured global wind and aerosol profiles from August 2018 to April 2023. As a high spectral resolution lidar (HSRL), ALADIN could directly retrieve the extinction coefficient. Targeting a large-scale tropospheric smoke transport event originating from the western US on 14 September and arriving over Europe on 21 September, a method for constructing an Aeolus smoke dataset was developed based on ALADIN observations, in synergy with multi-platform data. The backscatter coefficient in the smoke dataset was corrected using a linear depolarization ratio of 0.15, since ALADIN detected only co-polarized backscattered signals and the averaged smoke depolarization ratio remained relatively stable throughout the transport. Utilizing the selected cross-sections from the Aeolus smoke dataset, we acquired the vertical structure of the smoke layers and characterized their features. These layers show good agreement with the HYSPLIT simulations and are considered representative of different transport phases. Statistical analyses of the complete Aeolus smoke dataset from 14 to 21 September reveal the evolution of the smoke plume throughout its transatlantic transport. We illustrated the variations in aerosol optical depth, layer altitude and lidar ratio throughout the transport process. To our knowledge, this paper represents the first use of a spaceborne HSRL for observations and analyses of a large-scale tropospheric smoke transport. The comprehensive characterization presented offers valuable information for advancing global aerosol research.