文章基本信息

标题：Jupiter's Mesoscale Waves Observed at 5μm by Ground-based Observations and Juno JIRAM
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作者：Leigh N. Fletcher ; H. Melin ; A. Adriani 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2018
卷号：156
期号：2
页码：1-13
DOI：10.3847/1538-3881/aace02
语种：English
出版社：American Institute of Physics
摘要：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 μm 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 M-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 μm. The thermal structure of the NEB allows for both inertio-gravity waves and gravity waves. Despite detection at 5 μm, 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-μm 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.
关键词：planets and satellites: atmospheres;planets and satellites: gaseous planets;infrared: planetary systems