Studying drop production by collective bubble bursting for various bubble size distributions in laboratory experiments*

Bubbles entrained by breaking waves rise to the ocean surface, where they cluster before bursting and releasing droplets into the atmosphere. The ejected aerosols affect cloud formation and the radiative balance of the atmosphere, motivating a controlled study of drop production by collective bubble bursting through a laboratory-scale experiment. Using a 50x50x60 cm³ bubbling tank filled with solutions of artificial seawater, we make measurements of bulk bubbles, surface bubbles, drops, and dry particles for cases with a variety of initial bubble size distributions. As the bubble size distribution is changed, we analyze the corresponding change in the drop size distribution and attribute ejected drops of sizes 0.05-500 microns to associated bursting bubbles spanning 0.03-5 millimeters. We demonstrate that the measured drop production by collective bubble bursting can be described relatively well by the drop size distribution obtained by integrating scaling laws developed for single bubble bursting over the various bubble sizes measured in our experiments.