Methane, ethane, and mixed clouds in Titan's atmosphere: Properties derived from microphysical modeling

Convective cloud heights as a diagnostic for methane environment on Titan

“…The microphysics package was adapted from Barth and Toon (2006) and operates independently on each column. The model solves the continuity equation for a particle n of volume v, with the form…”

“…16 and 17 shows the Beard and Ochs (1984) coalescence and collision efficiencies for various particle sizes. Barth and Toon (2006) found coalescence to be negligible in their optically thin methane and ethane clouds (particle numbers were of order 10 À4 cm À3 , severely limiting the number of collisions). However, the greater number densities in convective clouds (e.g., Barth and Rafkin, 2007) increase the likelihood of collisions and coalescence is necessary to grow droplets large enough to create abundant precipitation.…”

Far-infrared opacity sources in Titan’s troposphere reconsidered

“…Solid CH 4 clouds are modelled using Mie theory and the optical constants of Martonchik and Orton (1994). We use a log-normal distribution of particle sizes, with an effective radius of 100 µm and a log(σ) value of 0.3 (after Barth and Toon, 2006). This distribution includes particles sizes between ∼40-250 µm and results in a flat extinction cross-section between 250-550 cm −1 and single scattering albedos close to unity.…”

Titan at 3 microns: Newly identified spectral features and an improved analysis of haze opacity

“…e Result of Coustenis et al (2007) for stratosphere. f Chudamani et al (1985) and Blass et al (1987) measured nitrogen-broadened line widths of C 2 H 6 to be 0.168 and 0.090 cm −1 atm −1 at 150 and 296 K, respectively; from which we derive the temperature dependent exponent to be 0.92. g Result of Coustenis et al (2007) for P < 30 mbar; the theoretical mixing ratio of Barth and Toon (2006) was adopted for P > 30 mbar.…”