When
3:45 p.m., Nov. 17, 2015
Where
Kuiper Space Sciences 312
Dr. Morgan O'Neill
Postdoctoral Fellow
Weizmann Institute of Science
A Theory for Polar Cyclones on Giant Planets
The poles of Saturn, Uranus and Neptune each have a 'hot spot' that is observable from Earth. Saturn, which has been observed in great detail by the orbiting Cassini mission, additionally exhibits Earth-sized hurricane-like cyclones on each pole. These massive cyclones have been present since they were first observed in 2004 and may be permanent. Our study proposes a mechanism for their creation: numerous small, moist convective thunderstorms, similar to those found embedded in Earth's hurricanes. These thunderstorms are ubiquitous features on Jupiter and Saturn. Hundreds of simulations suggest that these very small, short-lived storms can build and maintain a deep, rapid, large polar cyclone like we see on Saturn. Furthermore, an exploration of cyclone sensitivity to the Rossby deformation radius and total energy forcing suggests that Uranus and Neptune have transient polar cyclones, and Jupiter will not exhibit them. This last prediction will be tested for the first time next year, when the NASA Juno mission reaches Jupiter and finally observes the Jovian poles.
Host: Dr. Adam Showman
Postdoctoral Fellow
Weizmann Institute of Science
A Theory for Polar Cyclones on Giant Planets
The poles of Saturn, Uranus and Neptune each have a 'hot spot' that is observable from Earth. Saturn, which has been observed in great detail by the orbiting Cassini mission, additionally exhibits Earth-sized hurricane-like cyclones on each pole. These massive cyclones have been present since they were first observed in 2004 and may be permanent. Our study proposes a mechanism for their creation: numerous small, moist convective thunderstorms, similar to those found embedded in Earth's hurricanes. These thunderstorms are ubiquitous features on Jupiter and Saturn. Hundreds of simulations suggest that these very small, short-lived storms can build and maintain a deep, rapid, large polar cyclone like we see on Saturn. Furthermore, an exploration of cyclone sensitivity to the Rossby deformation radius and total energy forcing suggests that Uranus and Neptune have transient polar cyclones, and Jupiter will not exhibit them. This last prediction will be tested for the first time next year, when the NASA Juno mission reaches Jupiter and finally observes the Jovian poles.
Host: Dr. Adam Showman
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