Convective cloud heights as a diagnostic for methane environment on Titan

The appearance of convective clouds in Titan's troposphere has been documented from ground-based observation for more than a decade. Cloud tops have been reported between 14 and 25 km. Higher resolution Cassini data have shown smaller portions of the cloud system can reach up to 42 km. We use the Titan Regional Atmospheric Modeling System (TRAMS) to explore environments which allow convective clouds to reach the tropopause. In general, cloud tops remain below 30 km, but for environments where the surface humidity of methane is greater than 50%, a small portion at the center of the cloud rises briefly to higher altitudes for >= 65% humidity, the cloud top reaches nearly to the tropopause (similar to 40 km). A number of other parameters also have noticeable affects on cloud top such as nucleation critical saturation, haze abundance, and collisional growth of cloud particles. (C) 2009 Elsevier Inc. All rights reserved.