In this infrared view of the South Pole of Venus, the yellow area at the bottom is the daylit side of the planet. The two "eyes" of the polar vortex appear as red blobs near the pole (at center of image). Part of the cold collar that surrounds the polar vortices is visible in blue on the night side (upper half) of the image.
Click on image for full size
Image courtesy ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA.

The Polar Atmosphere of Venus

Venus has odd, swirling vortices in its atmosphere above each of the planet's poles. These vortex structures were first detected over the North Pole by NASA's Pioneer Venus Orbiter in 1978. The European Space Agency's (ESA) Venus Express discovered, and has been observing, vortices over the South Pole since it went into orbit in April 2006.

Polar vortices are actually common features on planets with atmospheres. A polar vortex forms in the winter at each pole on Earth. Saturn, too, has polar vortices. The vortices on Venus are peculiar because they are double vortices; each polar vortex has two "eyes" which the winds and clouds swirl around. Scientists don't fully understand the Venusian vortices and are continuing to study their behaviors.

Large, bright clouds periodically form over the poles. The clouds sometimes appear and dissipate within a few hours. These bright clouds can increase the albedo of the polar atmosphere by 30% as they reflect more sunlight back into space. Some scientists think that upwelling of sulfur dioxide from the lower atmosphere, stirred by the polar vortices, creates these clouds.

The polar vortices on Venus are surrounded by "collars" of colder air. These collars may form some sort of boundary between the polar vortices and the flow of the atmosphere at lower latitudes. Venus, like Earth, has a Hadley cell atmospheric circulation pattern on either side of the equator. The Venusian Hadley cell extends nearly to the poles, reaching about 60 north and south latitude (as compared to ~30 on Earth). The cold collars appear between about 60 and 70 latitude.

Venus has high-speed winds in its upper cloud deck, about 60-70 km (37-43 miles) above the planet's surface. At equatorial latitudes these winds rip along at 360 km/hr (224 mph). Poleward of 50 latitude the wind speeds quickly decline, dropping to zero at the poles.

The surface temperatures on Venus are extremely high, around 464 C (867 F). The incredibly dense atmosphere spreads this heat evenly over the surface and keeps it very steady through time. The nighttime side of the planet is just as hot as the daytime side, and poles of Venus are just as scorching hot as the equator. The spin axis of Venus is tilted a mild 3 (compared to Earth's 23). Due to this minimal tilt and the thick atmosphere, there are no seasons on Venus. Wherever you go... and whenever you go... on Venus, you can count on it being hot!

Last modified May 18, 2009 by Randy Russell.

You might also be interested in:

The Poles of Venus

Would you expect to find ice caps and snow fields on Venus? Not likely! Venus is the hottest planet in our Solar System, and those high temperatures extend right on up to the poles. Though there aren't...more


Clouds can come in all sizes and shapes, and can form near the ground or high in the atmosphere. Clouds are groups of tiny water droplets or ice crystals in the sky and are formed by different processes....more

Hadley Cell

The Hadley cell is an atmospheric circulation pattern in the tropics that creates winds called the tropical easterlies and the trade winds. In the Hadley cell, air rises up into the atmosphere at or near...more

Latitude and Longitude

The most common way to locate points on the surface of the Earth is by standard, geographic coordinates called latitude and longitude. These coordinates are measured in degrees and represent angular distances...more

An Overview of the Interior and Surface of Venus

Venus is the second planet from the Sun, and is Earth's neighbor in the solar system. Venus is the brightest object in the sky after the Sun and the Moon, and sometimes looks like a bright star in the...more

History of Venus Transits

Transits of Venus are extremely rare astronomical phenomena. They occur in pairs, separated by eight years, with more than a century elapsing between successive pairs of transits. There will be two Venus...more

Transits of Venus

The planet Venus periodically passes directly between Earth and the Sun. This event, which is somewhat similar to a solar eclipse, is called a transit of Venus. Viewed from Earth, Venus and Mercury are...more

The Polar Atmosphere of Venus

Venus has odd, swirling vortices in its atmosphere above each of the planet's poles. These vortex structures were first detected over the North Pole by NASA's Pioneer Venus Orbiter in 1978. The European...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