Europlanet Science Congress 2022
Palacio de Congresos de Granada, Spain
18 – 23 September 2022
Europlanet Science Congress 2022
Palacio de Congresos de Granada, Spain
18 September – 23 September 2022
EPSC Abstracts
Vol. 16, EPSC2022-208, 2022
Europlanet Science Congress 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Results from the professional-amateur collaboration to investigate the Cloud Discontinuity phenomenon in Venus’ atmosphere

Emmanouil Kardasis1, Javier Peralta2, Grigoris Maravelias1,3,4, Masataka Imai5, Anthony Wesley6, Tiziano Olivetti7, Yaroslav Naryzhniy8, Luigi Morrone9,10, Antonio Gallardo11, Giovanni Calapai12, Joaquin Camarena13, Paulo Casquinha14, Dzmitry Kananovich15, Niall MacNeill16, Christian Viladrich17, and Alexia Takoudi1
Emmanouil Kardasis et al.
  • 1Hellenic Amateur Astronomy Association, Glyfada-Athens, Greece (
  • 2Departamento de FAMN, Facultad de Física, Universidad de Sevilla, 41012 Sevilla, Spain
  • 3IAASARS, National Observatory of Athens, Lofos Nymfon, Thission, 11810 Athens, Greece
  • 4Institute of Astrophysics, FORTH, 70013 Heraklion, Greece
  • 5Faculty of Science, Kyoto Sangyo University, Kyoto 603-8555, Japan
  • 6Astronomical Society of Australia, Rubyvale, QLD 4702, Australia
  • 7Union of Italian Amateur Astronomers, Via Lazio, 14-00040 Rocca di Papa, 26100 Cremona, Italy
  • 8Independent Researcher, 09200 Kagarlyk, Kiev Region, Ukraine
  • 9AstroCampania Association, 80051 Agerola, Italy
  • 10British Astronomical Association, Burlington House, Piccadilly, London W1J 0DU, UK
  • 11Asociación Astronómica del Campo de Gibraltar “Luz Cero”, 11351 Castellar de la Frontera, Spain
  • 12Private Astronomical Observatory in Massa S. Giorgio, 98100 Messina, Italy
  • 13Agrupación Astronómica de la Safor, 46003 Valencia, Spain
  • 14Portuguese Association of Amateur Astronomers, 2780-048 Oeiras, Portugal
  • 15Faculty of Chemistry, Tallinn University of Technology, 19086 Tallinn, Estonia
  • 16Astronomy Society of NSW, P.O. Box 870, Epping, NSW 1710, Australia
  • 17Astroqueyras, 05350 Saint-Véran, France

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

How to cite: Kardasis, E., Peralta, J., Maravelias, G., Imai, M., Wesley, A., Olivetti, T., Naryzhniy, Y., Morrone, L., Gallardo, A., Calapai, G., Camarena, J., Casquinha, P., Kananovich, D., MacNeill, N., Viladrich, C., and Takoudi, A.: Results from the professional-amateur collaboration to investigate the Cloud Discontinuity phenomenon in Venus’ atmosphere, Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-208,, 2022.


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