Click on the image for the animation
This animation shows "beacons" of hot air seen in the infrared that appeared during a great springtime storm on Saturn from January 2011 to March 2012. These infrared hotspots in Saturn's northern hemisphere are shown in a side view and a top view of Saturn.
As clouds broke out in Saturn's stormy troposphere (true pattern not represented here), waves of heat travelled hundreds of miles (kilometers) upwards, depositing their energy as two vast "beacons" of hot air in the stratosphere. Both hotspots traveled in a westerly direction around the planet, but the larger of the two traveled much faster, lapping the smaller one before they merged to create an enormous vortex that for a brief period exceeded even the size of Jupiter's famous Great Red Spot. The giant vortex was visible only to infrared cameras, and persisted long after the clouds from the storm had faded away. The beacon complete a circuit around the planet once every 120 days and is expected to dissipate by the end of 2013.
The animation was created by the European Space Agency.