Aerosol-Cloud Measurements During the NASA NAAMES Campaign: Summary of Data and Cloud Droplet Sensitivities

We present a compiled dataset of airborne in situ measurements of aerosol and cloud microphysical properties and cloud condensation nuclei (CCN) spectra carried out during 2015-2018 as part of the 5-year North Atlantic Aerosols and Marine Ecosystems Study (NAAMES). These field campaigns target distinct cycles in the atmosphere above the annually-occurring North Atlantic phytoplankton bloom, which provide excellent opportunities to examine the influence of biogenic aerosols on CCN and clouds against a backdrop of both the presence and absence of anthropogenic pollution. Aerosol and cloud droplet number concentrations observed during November, 2015, were extremely low, while the addition of aerosol (by ~10- fold) during the Springtime increases cloud droplet number concentrations substantially. Results obtained during Fall 2017 are similar to those obtained in Spring 2016 in terms of mean aerosol loading. Meanwhile, the shape of the CCN supersaturation spectrum remains similar across all three deployments. In addition, we report the cloud droplet sensitivity to aerosol number, hygroscopicity, and cloud updraft velocity. The results of NAAMES and sensitivity of cloud droplet number to aerosol loading will be contextualized within the results of past airborne campaign targeting aerosol-cloud interactions.