Revisiting the Relationship between Atlantic Dust and Tropical Cyclone Activity using Aerosol Optical Depth Reanalyses: 2003-2018

Previous studies have noted a relationship between African dust and Atlantic tropical cyclone (TC) activity. However, due to the limitations of past dust analyses, the strength of this relationship remains uncertain. The emergence of aerosol reanalyses, including the Navy Aerosol Analysis and Prediction System Aerosol Optical Depth (AOD) reanalysis and the NASA MERRA-2, enables an investigation of the relationship between African dust and TC activity over the tropical Atlantic and Caribbean in a consistent way both temporally and spatially for 2003-2018. Significant negative correlations are obtained between June-August-averaged (JJA) Caribbean dust AOD (DAOD) and seasonal Atlantic Accumulated Cyclone Energy (ACE), while the correlation between JJA tropical North Atlantic DAOD and seasonal ACE is somewhat weaker. A composite analysis of three high versus three low JJA Caribbean DAOD years reveals large differences in overall Atlantic TC activity. We also show that JJA Caribbean DAOD is significantly correlated with large-scale fields associated with variability in interannual Atlantic TC activity including zonal wind shear, mid-level moisture and SST, as well as ENSO and the Atlantic Meridional Mode, implying confounding effects of these factors on the dust-TC relationship. Possible causes of this relation are also discussed.