Cassini CIRS retrievals of ammonia in Jupiter's upper troposphere

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2005.12.020 Byline: Richard K. Achterberg (a), Barney J. Conrath (b), Peter J. Gierasch (b) Keywords: Jupiter; atmosphere; Atmospheres; structure; Atmospheres; dynamics Abstract: The zonal mean ammonia abundance on Jupiter between the 400- and 500-mbar pressure levels is inferred as a function of latitude from Cassini Composite Infrared Spectrometer data. Near the Great Red Spot, the ammonia abundance is mapped as a function of latitude and longitude. The Equatorial Zone is rich in ammonia, with a relative humidity near unity. The North and South Equatorial Belts are depleted relative to the Equatorial Zone by an order of magnitude. The Great Red Spot shows a local maximum in the ammonia abundance. Ammonia abundance is highly correlated with temperature perturbations at the same altitude. Under the assumption that anomalies in ammonia and temperature are both perturbed from equilibrium by vertical motion, we find that the adjustment time constant for ammonia equilibration is about one third of the radiative time constant. Author Affiliation: (a) Science Systems and Applications, Inc., 10210 Greenbelt Road, Suite 600, Lanham, MD 20706, USA (b) Astronomy Department, Cornell University, Ithaca, NY 14853, USA Article History: Received 10 December 2004; Revised 8 December 2005