A long-lasting megastorm in the atmosphere above Venus’ south pole is more chaotic and unpredictable than previously thought. This is the finding of a new study that looked at the planet's polar atmosphere in greater detail than ever before, which was published Mar. 24 in Nature Geoscience.
Venus has a dense carbon-dioxide atmosphere that creates a surface pressure more than 90 times stronger than Earth’s at sea level and temperatures greater than 450 degrees Celsius, hot enough to melt lead. Though the planet rotates very slowly — a day on Venus lasts 243 Earth-days — its atmosphere travels at speeds of 360 km/hr, whipping around the planet in just four Earth-days. Satellites have spotted an S-shaped vortex with two eyes near each of its poles.
A polar vortex is a gigantic persistent cyclone-like storm hovering high in the atmosphere over a planet’s antipodes. Almost every planet or moon with a substantial atmosphere has been shown capable of possessing one, including Earth. They interact with and shape the long-term climatological patterns of an atmosphere and, at least on our own world, are important in modeling climate change and ozone depletion.
source @ http://www.wired.com/wiredscience/2013/03/venus-chaotic-vortex/?cid=co6639664