Resolving shallow cumulus clouds: insights from high-resolution airborne measurements 

During the EUREC4A field campaign over the Atlantic Ocean near Barbados, we flew the Max Planck CloudKite aboard the German research vessel Maria S. Merian. In addition to three-dimensional wind speed, temperature, and humidity data, the scientific payload aboard CloudKite captured about one million holograms and half a million particle-image-velocimetry images, primarily in shallow cumulus clouds. The collected data allow us to capture the droplet size distribution and turbulence features with unprecedented resolution, thanks to the fast acquisition rate of the instruments combined with the low true air speed of the tethered CloudKite aerostat. We found that the clouds exhibit extreme variations in droplet size distribution both near the edge and in the core. The cloud droplets also exhibit clusters and empty regions, especially near the cloud edge.