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arXiv · 1708.05179

Jupiter's North Equatorial Belt expansion and thermal wave activity ahead of Juno's arrival

L. N. Fletcher·G. S. Orton·J. A. Sinclair·P. Donnelly·H. Melin·J. H. Rogers·T. K. Greathouse·Y. Kasaba·T. Fujiyoshi·T. M. Sato·J. Fernandes·P. G. J. Irwin·R. S. Giles·A. A. Simon·M. H. Wong·M. Vedovato
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Abstract

The dark colors of Jupiter's North Equatorial Belt (NEB, $7-17^\circ$N) appeared to expand northward into the neighboring zone in 2015, consistent with a 3-5 year cycle of activity in the NEB. Inversions of thermal-IR imaging from the Very Large Telescope revealed a moderate warming and reduction of aerosol opacity at the cloud tops at $17-20^\circ$N, suggesting subsidence and drying in the expanded sector. Two new thermal waves were identified during this period: (i) an upper tropospheric thermal wave (wavenumber 16-17, amplitude 2.5 K at 170 mbar) in the mid-NEB that was anti-correlated with haze reflectivity; and (ii) a stratospheric wave (wavenumber 13-14, amplitude 7.3 K at 5 mbar) at $20-30^\circ$N. Both were quasi-stationary, confined to regions of eastward zonal flow, and are morphologically similar to waves observed during previous expansion events.

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L. N. Fletcher, G. S. Orton, J. A. Sinclair, P. Donnelly, H. Melin, J. H. Rogers, T. K. Greathouse, Y. Kasaba, T. Fujiyoshi, T. M. Sato, J. Fernandes, P. G. J. Irwin, R. S. Giles, A. A. Simon, M. H. Wong, M. Vedovato. 2017-08-17. Jupiter's North Equatorial Belt expansion and thermal wave activity ahead of Juno's arrival. https://doi.org/10.1002/2017gl073383

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