Titan's atmospheric temperatures, winds, and composition.

Temperatures obtained from early Cassini infrared observations of Titan show a stratopause at an altitude of 310 kilometers (and 186 kelvin at 15°S). Stratospheric temperatures are coldest in the winter northern hemisphere, with zonal winds reaching 160 meters per second. The concentrations of several stratospheric organic compounds are enhanced at mid- and high northern latitudes, and the strong zonal winds may inhibit mixing between these latitudes and the rest of Titan. Above the south pole, temperatures in the stratosphere are 4 to 5 kelvin cooler than at the equator. The stratospheric mole fractions of methane and carbon monoxide are (1.6 ± 0.5) × 10-2 and (4.5 ± 1.5) × 10-5, respectively.