Research in Engineering and Aviation

The Influence of Persistent Companion Clouds on Geophysical Vortex Dynamics

June/July 2010

Author(s): R.P. LeBeau, X. Deng, and C. Palotai

The Influence of Persistent Companion Clouds on Geophysical Vortex Dynamics, 40th AIAA Fluid Dynamics Conference and Exhibit, AIAA 2010-4300, Chicago, IL, Jun 28-Jul 1.


Large geophysical vortices provide some of the most dramatic features in the known atmospheres, from hurricanes on Earth to the Great Red Spot on Jupiter. A notable difference between the Great Red Spot and terrestrial hurricanes is that hurricanes are more dynamic, changing shape and location in response to internal and external conditions. In contrast, large vortices on the outer two gas giant planets, Uranus and Neptune, have exhibited a greater tendency toward dynamics more akin to hurricanes. The most notable of these dynamic vortices was the original Great Dark Spot observed by Voyager II in 1989, which through eight months of observation drifted towards the equator by ten degrees in latitude and oscillated in shape over an eight-day period during the month of closest observation. Also like hurricanes, it now appears that clouds also play a critical role in governing the dynamics of these features, most importantly in terms of persistent orographic companion clouds that form in the vicinity of some of these vortices. However, to better understand the vertical as well as horizontal motions requires highest resolution simulations of these features. This paper will discuss the evidence of cloud effects on the vortex dynamics and progress on achieving the higher resolution vortex simulations that more accurately simulate the cloud physics. A deeper exploration of the cloud-vortex interaction will give us a better understanding of the physics of the ice giant atmospheres. In turn, this may help elucidate the motions of hurricanes on Earth through the application of comparative planetology.