An Overview of Saharan Dust Outbreaks Observed During the NASA Convective Processes Experiment – Cabo Verde (CPEX-CV)

The NASA CPEX-CV field campaign deployed the NASA DC-8 to Sal Island, Cabo Verde to measure Saharan dust, winds, temperature, water vapor, and clouds and precipitation during September 2022. The DC-8 payload included a suite of active, passive, and in situ instrumentation equipped to study the impacts of convective environments across various spatiotemporal scales (e.g. tropical cyclones, African Easterly Waves, cold pools) on dust transport processes and variability in vertical and optical properties in the data-sparse tropical northern East Atlantic. In particular, dust-focused CPEX-CV flights targeted process-level sampling of transport and convective processes that are responsible for the transport of giant-sized dust particles across the tropical North Atlantic to the Caribbean. Additional operations in the field included close collaboration with the ground-based ASKOS and airborne (Calibration and Validation for Aeolus – Aerosols and Winds (CAVA-AW) components of the NASA-ESA Joint Aeolus Tropical Atlantic Campaign (JATAC) for coordinated validation of ESA’s spaceborne Aeolus wind lidar.

Here, we present analysis that investigates evolution of Saharan dust vertical distributions, optical properties, and particle size distribution with transport for several CPEX-CV Saharan dust events, including dust interactions with what would become Hurricane Fiona and a major outbreak with optical depth close to 4. Additionally, we highlight impacts of small-scale processes on dust variability, including the impact of orography on transport dust vertical distributions and presence of water vapor on dust optical properties. Finally, we compare observed dust distributions and variability to simulations from the NASA Goddard Earth Observing System (GEOS) global aerosol transport model to evaluate simulated dust non-sphericity and particle size distribution evolution with transport compared to those observed by the CPEX-CV payload.