Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 5 2005 10.5194/acpd-5-8209-2005 http://www.atmos-chem-phys-discuss.net/5/8209/2005/ http://www.atmos-chem-phys-discuss.net/5/8209/2005/acpd-5-8209-2005.html http://www.atmos-chem-phys-discuss.net/5/8209/2005/acpd-5-8209-2005.pdf 8209 8232 2005-09-08 A redistribution of water due to pileus cloud formation near the tropopause T. J. Garrett C. Liu J. Dean-Day B. K. Barnett G. G. Mace D. G. Baumgardner C. R. Webster T. P. Bui W. G. Read Department of Meteorology, University of Utah, Salt Lake City, UT, USA Atmospheric Chemistry and Dynamics Branch, NASA Ames Research Center, Moffett Field, CA, USA WB-57 Program Office, NASA Johnson Space Center,Ellington Field, Houston, Texas, USA Universidad Nacional Autonoma de Mexico, Mexico City, Mexico Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA, USA Thin stratiform clouds called pileus can form in the earth's atmosphere when humid air is lifted above rising convection. In the lower troposphere pileus lifetimes are short, so they have been considered little more than an attractive curiosity. This paper describes pileus cloud forming near the tropopause at low-latitudes, and discusses how they may be associated with a redistribution of water vapor and ice at cold temperatures.