Details

Autor(en) / Beteiligte

• Fletcher, Leigh N
• Melin, H
• Adriani, A
• Simon, A A
• Sanchez-Lavega, A
• Donnelly, P T
• Antuñano, A
• Orton, G S
• Hueso, R
• Kraaikamp, E
• Wong, M H
• Barnett, M
• Moriconi, M L
• Altieri, F
• Sindoni, G

Titel

Jupiter's Mesoscale Waves Observed at 5 μ m by Ground-based Observations and Juno JIRAM

Ist Teil von

• The Astronomical journal, 2018-08, Vol.156 (2), p.67

Ort / Verlag

United States: IOP Publishing

Erscheinungsjahr

2018

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• We characterize the origin and evolution of a mesoscale wave pattern in Jupiter's North Equatorial Belt (NEB), detected for the first time at 5 m using a 2016-17 campaign of "lucky imaging" from the VISIR instrument on the Very Large Telescope and the NIRI instrument on the Gemini observatory, coupled with -band imaging from Juno's JIRAM instrument during the first seven Juno orbits. The wave is compact, with a 1°.1-1°.4 longitude wavelength (wavelength 1300-1600 km, wavenumber 260-330) that is stable over time, with wave crests aligned largely north-south between 14°N and 17°N (planetographic). The waves were initially identified in small (10° longitude) packets immediately west of cyclones in the NEB at 16°N but extended to span wider longitude ranges over time. The waves exhibit a 7-10 K brightness temperature amplitude on top of an ∼210 K background at 5 m. The thermal structure of the NEB allows for both inertio-gravity waves and gravity waves. Despite detection at 5 m, this does not necessarily imply a deep location for the waves, and an upper tropospheric aerosol layer near 400-800 mbar could feature a gravity wave pattern modulating the visible-light reflectivity and attenuating the 5- m radiance originating from deeper levels. Strong rifting activity appears to obliterate the pattern, which can change on timescales of weeks. The NEB underwent a new expansion and contraction episode in 2016-17 with associated cyclone-anticyclone formation, which could explain why the mesoscale wave pattern was more vivid in 2017 than ever before.