The UVS instrument on the Juno mission records far-ultraviolet reflected sunlight from Jupiter. These spectra are sensitive to the abundances of chemical species in the upper atmosphere and to the distribution of the stratospheric haze layer. We combine observations from the first 30 perijoves of the mission in order to study the meridional distribution of acetylene (C2H2) in Jupiter's stratosphere. We find that the abundance of C2H2 decreases towards the poles by a factor of 2-4, in agreement with previous analyses of mid-infrared spectra. This result is expected from insolation rates: near the equator, the UV solar flux is higher, allowing more C2H2 to be generated from the UV photolysis of CH4. The decrease in abundance towards the poles suggests that horizontal mixing rates are not rapid enough to homogenize the latitudinal distribution.
@article{arxiv.2107.11295,
title = {Meridional variations of C$_2$H$_2$ in Jupiter's stratosphere from Juno UVS observations},
author = {Rohini S. Giles and Thomas K. Greathouse and Vincent Hue and G. Randall Gladstone and Henrik Melin and Leigh N. Fletcher and Patrick G. J. Irwin and Joshua A. Kammer and Maarten H. Versteeg and Bertrand Bonfond and Denis C. Grodent and Scott J. Bolton and Steven M. Levin},
journal= {arXiv preprint arXiv:2107.11295},
year = {2021}
}