Venus's southern polar vortex reveals precessing circulation.

• Published in: Science
• Main Authors: Luz, D, Berry, D, Piccioni, G, Drossart, P, Politi, R, Wilson, C, Erard, S, Nuccilli, F
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: North Pole; South Pole; Venus; South pole
• Online Access: https://doi.org/10.1126/science.1201629; https://ora.ox.ac.uk/objects/uuid:b810e2fa-7fb2-4962-9b99-b44fbfdebdf6

Initial images of Venus's south pole by the Venus Express mission have shown the presence of a bright, highly variable vortex, similar to that at the planet's north pole. Using high-resolution infrared measurements of polar winds from the Venus Express Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument, we show the vortex to have a constantly varying internal structure, with a center of rotation displaced from the geographic south pole by ~3 degrees of latitude and that drifts around the pole with a period of 5 to 10 Earth days. This is indicative of a nonsymmetric and varying precession of the polar atmospheric circulation with respect to the planetary axis.