Venus’s Southern Polar Vortex Reveals Precessing Circulation

• Main Authors: Luz, David, Berry, David, Piccioni, Giuseppe, Drossart, Pierre, Politi, Romolo, Wilson, Colin, Erard, Stéphane, Nuccilli, Fabrizio
• Format: Article in Journal/Newspaper
• Language: English
• Published: Science 2011
• Subjects: Venus; Atmosphere; Vortex; North Pole; South pole
• Online Access: http://hdl.handle.net/10174/4178

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 non symmetric and varying precession of the polar atmospheric circulation with respect to the planetary axis.