1906.11088v1.pdf (4.6 MB)
Jupiter's Atmospheric Variability from Long-term Ground-based Observations at 5 μm
journal contributionposted on 2019-07-03, 09:09 authored by A Antuñano, LN Fletcher, GS Orton, H Melin, S Milan, J Rogers, T Greathouse, J Harrington, PT Donnelly, R Giles
Jupiter's banded structure undergoes strong temporal variations, changing the visible and infrared appearance of the belts and zones in a complex and turbulent way through physical processes that are not yet understood. In this study, we use ground-based 5-μm infrared data captured between 1984 and 2018 by eight different instruments mounted on the Infrared Telescope Facility in Hawai'i and on the Very Large Telescope in Chile to analyze and characterize the long-term variability of Jupiter's cloud-forming region at the 1–4 bar pressure level. The data show a large temporal variability mainly at the equatorial and tropical latitudes, with a smaller temporal variability at mid-latitudes. We also compare the 5-μm-bright and -dark regions with the locations of the visible zones and belts, and we find that these regions are not always colocated, especially in the southern hemisphere. We also present Lomb–Scargle and Wavelet Transform analyses in order to look for possible periodicities of the brightness changes that could help us understand their origin and predict future events. We see that some of these variations occur periodically in time intervals of 4–8 yr. The reasons for these time intervals are not understood, and we explore potential connections to both convective processes in the deeper weather layer and dynamical processes in the upper troposphere and stratosphere. Finally, we perform a Principal Component analysis to reveal a clear anticorrelation on the 5 μm brightness changes between the North Equatorial Belt and the South Equatorial Belt, suggesting a possible connection between the changes in these belts.
AA and LNF are supported by a European Research Council Consolidator Grant under the European Union’s Horizon 2020 research and innovation program, grant agreement number 723890, at the University of Leicester. LNF is also supported by a Royal Society Research Fellowship. HR is supported by UK Science and Technology Facilities Council (STFC) Grant ST/N000749/1. PTD is supported by UK Science and Technology Facilities Council (STFC). A portion of this work was performed by GSO at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. We are grateful to thank all those involved in the acquisition of these 5-µm data over many years, including but not limited to Kevin Baines, Jim Friedson, Tom Momary, Jose Luis Ortiz, John Spencer and Padma YanamandraFisher. Part of this investigation is based on data acquired at the Infrared Telescope Facility, which is operated by the University of Hawaii under Cooperative Agreement no. NNX-08AE38A with the National Aeronautics and Space Administration, Science Mission Directorate, Planetary Astronomy Program. We recognize the significant cultural role of Maunakea within the indigenous Hawaiian community, and we appreciate the opportunity to conduct our Jupiter observations from this revered site.
CitationAstronomical Journal, 2019 AJ 158 130
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
- AM (Accepted Manuscript)