Simulations of large scale cloud features on Outer Solar System planets
Abstract
In recent years, observations of solar system objects have skyrocketed, and we have high resolution maps of surface and atmospheric features. Ubiquitous among these are clouds, especially in the gas giant planets, e.g., Juno's observations of the Great Red Spot as well as multiple smaller vortical features and recent discoveries of companion clouds around new Dark Spots on Neptune (Wong et al, 2015), to name a few. With this explosion in data, there is more potential than ever to understand the underlying phenomenon that drive the atmosphere of these giant planets. In this work, we use the updated Explicit Planetary Isentropic-Coordinate (EPIC) model coupled with active, multi-species cloud microphysics, which has previously been used to study the Great Red Spot and Oval BA (Palotai et al, 2014), to simulate the 24-degree north jet on Jupiter and the Great Dark Spot of 1989 on Neptune. We present results from our 3-dimensional hydrodynamic simulations with the addition of water and ammonia condensation on Jupiter, and a methane cycle on Neptune to model the effects of cloud on large scale vortical systems. On Jupiter, we introduce small scale perturbations randomly throughout the jet region. These perturbations evolve to form distinct cloud features whose vertical structure varies significantly within and outside the jet. We test the effect of different bulk abundance of the condensibles on the stability and progression of these features. We see that the ammonia cloud layer is generally higher in altitude inside the jet, and also the inception of warm, dry areas which are lacking in clouds. On Neptune, Voyager 2 observed the Great Dark Spot in 1989, and its oscillation in shape and equatorward latitudinal drift. We analyze the effect of different deep abundance values and initial supersaturation of methane on the stability and the drift rate of the vortex, and its influence on the formation of companion clouds. Our initial results show that the deep abundance strongly impacts both the drift rate and the stability of the vortex, with higher values being more stable and some cases showing strong agreement with the observed drift rate.
- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #50
- Pub Date:
- October 2018
- Bibcode:
- 2018DPS....5050308S