Atmosphere (Feb 2022)

Amateur Observers Witness the Return of Venus’ Cloud Discontinuity

  • Emmanuel (Manos) Kardasis,
  • Javier Peralta,
  • Grigoris Maravelias,
  • Masataka Imai,
  • Anthony Wesley,
  • Tiziano Olivetti,
  • Yaroslav Naryzhniy,
  • Luigi Morrone,
  • Antonio Gallardo,
  • Giovanni Calapai,
  • Joaquin Camarena,
  • Paulo Casquinha,
  • Dzmitry Kananovich,
  • Niall MacNeill,
  • Christian Viladrich,
  • Alexia Takoudi

DOI
https://doi.org/10.3390/atmos13020348
Journal volume & issue
Vol. 13, no. 2
p. 348

Abstract

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Firstly identified in images from JAXA’s orbiter Akatsuki, the cloud discontinuity of Venus is a planetary-scale phenomenon known to be recurrent since, at least, the 1980s. Interpreted as a new type of Kelvin wave, this disruption is associated to dramatic changes in the clouds’ opacity and distribution of aerosols, and it may constitute a critical piece for our understanding of the thermal balance and atmospheric circulation of Venus. Here, we report its reappearance on the dayside middle clouds four years after its last detection with Akatsuki/IR1, and for the first time, we characterize its main properties using exclusively near-infrared images from amateur observations. In agreement with previous reports, the discontinuity exhibited temporal variations in its zonal speed, orientation, length, and its effect over the clouds’ albedo during the 2019/2020 eastern elongation. Finally, a comparison with simultaneous observations by Akatsuki UVI and LIR confirmed that the discontinuity is not visible on the upper clouds’ albedo or thermal emission, while zonal speeds are slower than winds at the clouds’ top and faster than at the middle clouds, evidencing that this Kelvin wave might be transporting momentum up to upper clouds.

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