Meridional Transport in the Stratosphere of Jupiter

The Cassini measurements of C2H2 and C2H6 at ∼5 mbar provide a constraint on meridional transport in the stratosphere of Jupiter. We performed a two-dimensional photochemical calculation coupled with mass transport due to vertical and meridional mixing. The modeled profile of C2H2 at latitudes less than 70 follows the latitude dependence of the solar insolation, while that of C2H6 shows little latitude dependence, consistent with the measurements. In general, our model study suggests that the meridional transport timescale above 5-10 mbar altitude level is &1000 years and the time could be as short as 10 years below 10 mbar level, in order to fit the Cassini measurements. The derived meridional transport timescale above the 5 mbar level is a hundred times longer than that obtained from the spreading of gas-phase molecules deposited after the impact of Shoemaker-Levy 9 comet. There is no explanation at this time for this discrepancy. Subject headings: planetary systems—radiative transfer—atmospheric effects— planets and satellites: individual (Jupiter)— methods: numerical