Major differences between two atmospheric reanalyses seen by an aerosol atmospheric river detection algorithm

Aerosol Atmospheric Rivers (AARs) are long, narrow regions in the atmosphere transporting large concentrations of aerosols. Previous literature focused on AARs detected only based on MERRA-2 reanalysis data. In this study, global AAR catalogues of different species (organic carbon, black carbon, and dust) are constructed for the 2003 – 2023 period by applying an AAR detection algorithm to two reanalysis products: MERRA-2 and CAMS. These catalogues provide information regarding the location and extension of the AARs found at 6-hourly timesteps, as well as their geometric characteristics (length, width) and their tracking over time. Results show large discrepancies between the catalogues based on the two reanalyses. Specifically, substantial differences are found between the spatial and temporal frequencies of occurrence of AARs in for each aerosol species considered. These findings underscore the need for caution when using AAR catalogues obtained from only one reanalysis product.