Venus's Southern Polar Vortex Reveals Precessing Circulation

• Published in: Science (American Association for the Advancement of Science) Vol. 332; no. 6029; pp. 577 - 580
• Main Authors: Luz, D., Berry, D. L., Piccioni, G., Drossart, P., Politi, R., Wilson, C. F., Erard, S., Nuccilli, F.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 29.04.2011; The American Association for the Advancement of Science; American Association for the Advancement of Science (AAAS)
• Subjects: Astronomy; Astrophysics; Atmosphere; Atmospheric circulation; Centroids; Earth, ocean, space; Exact sciences and technology; Kinetics; Neutral atmospheres; Orbits; Physics; Planetary rotation; Planetary, asteroid, and satellite characteristics and properties; Planets, their satellites and rings. Asteroids; Polar orbits; Polar regions; Solar orbits; Solar system; Spectrum analysis; Tropical regions; Venus; Vortices; Antarctica, South Pole; PN, Arctic, North Pole; Planetary atmospheres; Atmospheric circulation; Venus planet; Precession; Vortices; Internal structure; Polar wind
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1201629

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.