Saturn has a huge hurricane-like storm at its South Pole. The vast, swirling vortex is about 8,000 km (5,000 miles) across! The Cassini spacecraft captured this image in October 2006.
Click on image for full size
Image courtesy of NASA/JPL/Space Science Institute.

Saturn's Southern Polar Vortex

Saturn's South Pole is an extremely stormy and surprisingly warm region. A vast, hurricane-like storm centered on the South Pole dominates the area. Astonishingly, the pole is also warmer than any other place on the ringed planet.

Infrared images from the Keck telescope in Hawaii in 2005 provided astronomers with a "thermal map" of Saturn. With it, scientists were able to see which parts of Saturn are especially warm and which places are cooler. To their astonishment, the astronomers saw that Saturn's South Pole is the hottest part of the ringed planet! A bright dot at the pole in the infrared image indicated that the temperature at the pole is about 60° C (108° F) higher than at the equator! One scientist commented that if this temperature pattern were seen on Earth, it would be "like discovering that Antarctica is hotter than the Sahara Desert". Saturn's Southern Hemisphere has been experiencing the summer season, and thus greater warming by the Sun, for several years (a year on Saturn is almost 30 Earth years long, so seasons on the ringed planet last 7+ years). However, the extent of the heating at the pole and the sharp rise in temperature very close to the pole cannot be explained by seasonal warming alone.

On Earth, a large atmospheric structure called a "polar vortex" often forms over each pole during its winter season. Earthly polar vortices trap especially cold air around the poles. On Saturn, the atmospheric flows around the South Pole are reminiscent of the polar vortex structures on Earth. However, they seem to trap warmer air - not colder - near the poles. Scientists are trying to figure out why this is the case.

High temperatures at the pole probably provide the energy that drives the enormous hurricane-like storm found there. Discovered by the Cassini spacecraft in October 2006, the storm has spiral cloud bands, high wind speeds, and a gigantic eyewall reminiscent of hurricanes on Earth. Unlike Earthly hurricanes, which move around, Saturn's "polar hurricane" seems locked in place over the pole.

How big of a storm is this "polar hurricane"? Much larger than its Earthly counterparts, the storm on Saturn extends outward thousands of kilometers (miles) from the pole. The central eye is about 1,500 kilometers (930 miles) in diameter. Clouds in the eyewall tower 30 to 75 kilometers (19 to 47 miles) above their surroundings, some 2 to 5 times higher than in hurricanes on Earth. Winds around the polar vortex can reach speeds of 550 km/hour (342 miles per hour), spawning hundreds of smaller, swirling storms.

Saturn's "polar hurricane" is the first storm with an eyewall discovered beyond Earth. Even Jupiter's Great Red Spot, which is much larger than Saturn's storm, does not have an eye or an eyewall.

Last modified January 20, 2009 by Randy Russell.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

The Poles of Saturn and Its Moons

There's a lot of strange and interesting stuff going on at both the North and South Poles of Saturn. Features at the poles of two of Saturn's moons, Titan and Enceladus, have also grabbed the attention...more

Antarctica

Antarctica is unique. It is the coldest, windiest, and driest continent on Earth. The land is barren and mostly covered with a thick sheet of ice. Antarctica is almost entirely south of the Antarctic Circle...more

The Desert Biome

Deserts are full of interesting questions. How can anything survive in a place with hardly any water? Why is it so dry to begin with? You can find at least one desert on every continent except Europe....more

What Causes the Seasons?

Let's get rid of some common misconceptions about the seasons. The Earth's orbit is in the shape of an ellipse, so that sometimes the Earth is a little bit closer to the Sun than at other times. Is this...more

The Polar Atmosphere

Phenomena in the Polar Atmosphere There are some unique phenomena that happen in the atmosphere that is above the Earth's polar regions. Read on to discover more about some of the unique parts of the polar...more

An Overview of Motions in Saturn's Atmosphere

The most important motions in the atmosphere are winds. The major winds in Saturn's atmosphere are the zonal winds which are composed of alternating belts and zones flowing in opposite directions. Belts...more

Cassini

The Cassini probe began its journey to Saturn on October 15, 1997. It flew by Earth in August, 1999, before heading towards the distant planet. Cassini passed Jupiter in 2000 and then burned towards its...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA