Temporal Variations in the Vertical Structure of Jupiter's Atmosphere
Abstract
We present models of Jupiter's center-to-limb reflectivity at wavelengths ranging from the near-ultraviolet to the near-infrared, the largest wavelength range ever used in such an analysis. In particular, we modeled center-to-limb scans of four latitudes using a multi-layered model of Jupiter's atmospheric vertical structure. Modeling Jupiter's center-to-limb reflectivity in methane absorption bands of different strengths allows us to probe the optical depths of the different gas layers. Modeling at continuum wavelengths yields information about the haze and cloud layers. The imaging data were collected using the Apache Point Observatory 3.5 meter telescope, the New Mexico State University 0.6 meter telescope, and the Hubble Space Telescope. Our standard model for the jovian atmospheric structure consists of two cloud decks and a stratospheric haze layer, all interleaved with aerosol-free gas layers. The radiative transfer code uses a doubling adding algorithm that performs a gradient search of the parameter space using a linearization of the fitting function. We added new opacity sources and the associated calculations to an existing program to adapt the model to our extended wavelength range. The model was also used to fit reflectivity variations of the convective plumes and adjacent dark regions in the north Equatorial Zone, at the latitude of the Galileo Probe entry. We find that the recovery time of Jupiter's atmosphere after a convective disturbance can be as long as seven years. Episodic events such as a South Equatorial Belt Disturbance can result in a variation in the ammonia cloud single scattering albedo and the optical depth of the stratospheric haze layer. Access to near-infrared wavelengths has allowed us to characterize the variability of the stratosphere for the first time. The stratospheric haze layer has its highest extent (not including the polar regions) above the northern Equatorial Zone. Active convection is likely the source of at least some of this haze material. The Comet Shoemaker-Levy 9 impacts into the jovian atmosphere also likely had an effect on the atmospheric vertical structure in Jupiter's southern hemisphere. There does not appear to be a difference in cloud top altitude for the equatorial plumes and the adjacent dark regions. Sensitivity tests motivated by the preliminary results from the Galileo probe net flux radiometer and nephelometer experiments indicate that the ammonia cloud deck may have a patchy structure.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- November 1997
- Bibcode:
- 1997PhDT.........8C
- Keywords:
-
- CONVECTIVE DISTURBANCE;
- CENTER TO LIMB REFLECTIVITY;
- Physics: Astronomy and Astrophysics, Physics: Atmospheric Science