Structure of the Jovian stratosphere at the Galileo probe entry site

The structure of the Jovian stratosphere at the Galileo probe entry site is investigated through calculations of radiative heating rates based on measurements of the temperature profile, composition, and aerosol distribution. From analysis of mid-IR observations of Jupiter, we determine a C2H2 mole fraction of 1.1-4.3 x 10(-6) at 0.01 mbar, and a C2H6 mole fraction of 2.8-6.5 x 10-6 at 0.4-10 mbar. The derived distributions imply that C2H6 and C2H2 are the most important coolants in the Jovian stratosphere from 0.004 to 10 mbar, and that the stratosphere is close to radiative equilibrium. In Jupiter's stratosphere, as in the stratosphere of the Earth, photochemical species play an essential role in the energy balance. (C) 2001 Academic Press.