Vertical Distribution of Saharan Dust during the NASA CPEX-CV Campaign

Saharan dust has a number of effects on the atmosphere, such as changes to radiative forcing and influence on tropical cyclones. The vertical distribution of this dust needs to be well understood to fully characterize its effects. Previous research has focused on the climatological distribution of Saharan dust and case studies into specific plumes. However, interactions between dust and tropical cyclones are more complex. This research characterizes the vertical distribution of Saharan dust during the NASA Convective Processes Experiment – Cabo Verde (CPEX-CV) campaign, with analyses performed for the full campaign and for dust near Tropical Storm Hermine. For the full campaign, data mainly come from the High Altitude Lidar Observatory (HALO) airborne instrument. Aerosol composition is determined using dust mixing ratio and aerosol ID, and vertical distribution is determined using backscatter profiles. Dust tends to occur in either the low-to-mid-troposphere (1 km to 6 km) or the mixing layer (below 1 km), and the altitude of dust tends to decrease going westward. These results are consistent with the established understanding of the long-term distribution of Saharan dust. For the analysis of dust near Tropical Storm Hermine, data mainly come from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument aboard the CALIPSO satellite. Again, aerosol ID is used to determine composition, while backscatter profiles indicate the distribution of dust in the atmosphere. Profiles of dust before and after the passage of Hermine are used to characterize the vertical redistribution of dust caused by the storm. Further research will combine data from CPEX-CV flights near and into Hermine with results from CALIOP to gain more insight into the dust redistribution process. Ultimately, this may improve our understanding of how dust and tropical cyclones interact.