A large cloud outburst at Titan's south pole

• Published in: Icarus
• Main Authors: Schaller, Emily L., Brown, Michael E., Roe, Henry G., Bouchez, Antonin H.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier 2006
• Subjects: Titan; Infrared observations; Atmospheres; dynamics; Meteorology; Griffith; South Pole; South pole
• Online Access: https://doi.org/10.1016/j.icarus.2005.12.021

Images of Titan acquired over five nights in October 2004 using the adaptive optics system at the Keck Observatory show dramatic increases in tropospheric cloud activity at the south pole compared with all other images of Titan clouds to date. During this time, Titan's south polar clouds brightened to more than 18 times their typical values. The Cassini Ta flyby of Titan occurred as this storm was rapidly dissipating. We find that the brightness of this cloud outburst is consistent with the dramatic transient brightening of Titan observed in atmospheric windows on two nights in 1995 by Griffith et al. [Griffith, C.A., Owen, T., Miller, G.A., Geballe, T., 1998. Nature 395 (6702) 575–578] if we scale the brightness of the cloud by projecting it onto the equator. While apparently infrequent, the fact that large cloud events have been observed in different seasons of Titan's year indicates that these large storms might be a year-round phenomenon on Titan. We propose possible mechanisms to explain these occasional short-term increases in Titan's cloud activity. © 2006 Elsevier Inc. Received 8 July 2005; revised 6 December 2005. Available online 13 February 2006. E.L.S. is supported by an NSF Graduate Research Fellowship. H.G.R. is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under Award AST-0401559. Additional support was provided by NSF Award AST-0307929. We thank Andy Ingersoll and two anonymous referees for helpful comments. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The observatory was made possible by the generous financial support of the W.M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community.We are most fortunate to have the opportunity ...