Cloud morphology and dynamics in Saturn's northern polar region
| Autor: | Teresa del Río-Gaztelurrutia, Arrate Antuñano, Agustín Sánchez-Lavega, Javier Rodríguez-Aseguinolaza |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Baroclinity Astronomy and Astrophysics Astrophysics Atmospheric sciences 01 natural sciences Vortex Space and Planetary Science Anticyclone Polar vortex Barotropic fluid Saturn 0103 physical sciences Polar Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Physics::Atmospheric and Oceanic Physics Saturn's hexagon 0105 earth and related environmental sciences |
| Zdroj: | Icarus. 299:117-132 |
| ISSN: | 0019-1035 |
| Popis: | We present a study of the cloud morphology and motions in the north polar region of Saturn, from latitude ∼ 70°N to the pole based on Cassini ISS images obtained between January 2009 and November 2014. This region shows a variety of dynamical structures: the permanent hexagon wave and its intense eastward jet, a large field of permanent “puffy” clouds with scales from 10 – 500 km, probably of convective origin, local cyclone and anticyclones vortices with sizes of ∼1,000 km embedded in this field, and finally the intense cyclonic polar vortex. We report changes in the albedo of the clouds that delineate rings of circulation around the polar vortex and the presence of “plume-like” activity in the hexagon jet, in both cases not accompanied with significant variations in the corresponding jets. No meridional migration is observed in the clouds forming and merging in the field of puffy clouds, suggesting that their mergers do not contribute to the maintenance of the polar vortex. Finally, we analyze the dominant growing modes for barotropic and baroclinic instabilities in the hexagon jet, showing that a mode 6 barotropic instability is dominant at the latitude of the hexagon. |
| Databáze: | OpenAIRE |
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