Multiple convective storms within a single cyclone on Saturn

Abstract

Here we describe a cyclone at 50∘N in the atmosphere of Saturn that was the source of eight separate convective storms. The storm clouds that appeared bright in scattered sunlight were identified using images from the Cassini Imaging Science Subsystem (ISS) and ground-based telescopes. The Cassini Radio and Plasma Wave Science (RPWS) instrument detected Saturn Electric Discharge (SED) signals from the lightning within the storms, which were correlated to the sudden appearance of bright storm clouds in and surrounding the cyclone. Using the number and flash rate of SEDs we infer the duration and intensity of the storms. Although previous storms have been observed to erupt from within cyclones, the cyclone studied here is unusual in that it survived six storms before being disrupted by the seventh and strongest storm. An eighth storm occurred in the remnant of the disrupted cyclone. We conjecture that the anticyclonic circulation generated by the seventh storm was enough to overwhelm the cyclone’s gradient wind balance.