Meridional transport in the stratosphere of Jupiter

The Cassini measurements of C_2H_2 and C_2H_6 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 C_2H_2 at latitudes less than 70° follows the latitude dependence of the solar insolation, while that of C_2H_6 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 yr, and the time could be as short as 10 yr below 10 mbar level, in order to fit the Cassini measurements. The derived meridional transport timescale above the 5 mbar level is 100 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.