Development and Application of Computational Simulations for Observed Persistant and Time-Varying Phenomena in the Atmospheres of the Ice Giants

It has now been nearly two decades since our last close look at Uranus and Neptune with Voyager II. Since that time, the atmospheres ofthese planets have experienced dramatic changes observed through the Hubble Space Telescope and other terrestrial observations. Since there is no immediate prospect for a new GaIileo or Cassini-type mission to these planets, the quality and frequency of observational data for these planets is not going to change dramatically in the near future. Therefore, this project aims to leverage the past and current observations by creating a general circulation model specifically oriented towards utilizing features typically observed--primarily clouds and larger vortices. This model starts with the EPIC GCM, which has already been used to simulate vortex and cloud features on the ice giants, but refines it to specifically address available data for Uranus and Neptune. Previous observations, including Voyager II, will provide the basis for validating this model, while current and future observations will be used to provide initial conditions and modeling constraints. The model will also provide linkage between discrete observational data sets, effectively filling in the evolutionary gaps while providing a means to further investigate the physics underlying new phenoma. In the long term, the model will hopefully prove predictive, being able to suggest the evolution offeatures and thereby guide proposed observations of these planets. In conjunction with similar ongoing simulation efforts by others of Jupiter and Saturn, this effort will also create a comparative planetology computational laboratory. Such results will directly support Strategic Goal 3 of NASA, specifically sub-goals 3B and 3C, while providing a framework in which to consider observations of Uranus and Neptune, promoting a greater understanding of these planets. FORM NRESS-300 Version 2.0 Apr-06-05