Ammonia in Jupiter's troposphere from high-resolution 5 μm spectroscopy

Journal article

Jupiter's tropospheric ammonia (NH 3 ) abundance is studied using spatially resolved 5 μm observations from the cryogenic high-resolution infrared spectrograph (CRIRES) at the European Southern Observatory's Very Large Telescope. The high-resolving power (R = 96,000) allows the line shapes of three NH 3 absorption features to be resolved. We find that within the 1-4 bar pressure range, the NH 3 abundance decreases with altitude. The instrument slit was aligned north-south along Jupiter's central meridian, allowing us to search for latitudinal variability. There is considerable uncertainty in the large-scale latitudinal variability, as the increase in cloud opacity in zones compared to belts can mask absorption features. However, we do find evidence for a strong NH 3 enhancement at 4-6°N, consistent with a localized “ammonia plume“ on the southern edge of Jupiter's North Equatorial Belt.

Authors: Giles, R; Fletcher, L; Irwin, P; Orton, G; Sinclair, J

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Geophysical Union
• Journal: Geophysical Research Letters
• Volume: 44
• Issue: 21
• Pages: 10,838–10,844
• Publication date: 2017-11-04
• Acceptance date: 2017-10-06
• DOI: 10.1002/2017GL075221
• EISSN: 1944-8007
• ISSN: 0094-8276
• Keywords: ammonia; Jupiter; troposphere; composition