A Long-lived Sharp Disruption on the Lower Clouds of Venus



Planetary-scale waves are thought to play a role in powering the yet-unexplained atmospheric superrotation of Venus.

Puzzlingly, while Kelvin, Rossby and stationary waves manifest at the upper clouds (65--70 km), no planetary-scale waves or stationary patterns have been reported in the intervening level of the lower clouds (48--55 km), although the latter are probably Lee waves.

Using observations by the Akatsuki orbiter and ground-based telescopes, we show that the lower clouds follow a regular cycle punctuated between 30∘N--40∘S by a sharp discontinuity or disruption with potential implications to Venus's general circulation and thermal structure. This disruption exhibits a westward rotation period of ∼4.9 days faster than winds at this level (∼6-day period), alters clouds' properties and aerosols, and remains coherent during weeks.

Past observations reveal its recurrent nature since at least 1983, and numerical simulations show that a nonlinear Kelvin wave reproduces many of its properties.

J. Peralta, T. Navarro, C. W. Vun, A. Sánchez-Lavega, K. McGouldrick, T. Horinouchi, T. Imamura, R. Hueso, J. P. Boyd, G. Schubert, T. Kouyama, T. Satoh, N. Iwagami, E. F. Young, M. A. Bullock, P. Machado, Y. J. Lee, S. S. Limaye, M. Nakamura, S. Tellmann, A. Wesley, P. Miles

Comments: 21 pages, 10 figures, 2 animated figures and 2 tables
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Atmospheric and Oceanic Physics (physics.ao-ph)
Journal reference: Geophysical Research Letters, Volume 47, Issue 11, 16 June 2020, e2020GL087221
DOI: 10.1029/2020GL087221
Cite as: arXiv:2005.13540 [astro-ph.EP] (or arXiv:2005.13540v1 [astro-ph.EP] for this version)
Submission history
From: Javier Peralta
[v1] Wed, 27 May 2020 17:23:15 UTC (36,195 KB)

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