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This image of Martian clouds illustrates the fact that they are found only in the equatorial region.
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Image from: Hubble

Martian Clouds

Unlike the Earth, where clouds are found around the entire globe, on Mars, clouds seem to be plentiful only in the middle latitudes, as shown in this Hubble telescope image. This may be because water of Mars may only be found at mid-latitudes. Many of the cloud formations also seem to be due to topographic forcing by Olympus Mons.

As early as 1796 scientists were reporting "yellow", and "white" or "bluish" clouds in the Martian atmosphere. However, it wasn't until the Mariner 9 mission that clouds of water were positively identified. Mars Global Surveyor is providing more proof of the existence of water clouds.

More study is needed to understand just how the clouds come and go in the Martian atmosphere. For example, even though clouds have been found, there is still little evidence when and where it actually rains on Mars, if at all. Atmospheric temperatures reported by Mars Pathfinder during its decent indicate that it may be too cold in the cloud forming region of the Martian atmosphere for droplets to fall to the ground as liquid, but it may be cold enough for the condensation of CO2 droplets.

As a first step in answering some of those questions, Mars Pathfinder took measurements of many clouds in the Martian sky from the surface of Mars itself. Scientists are studying images of the Martian sky from the 80-day mission to get their first assessment of Martian weather patterns. The Mars '98 mission will carry a weather sounder, much like a terrestrial weather satellite. Then scientists expect to receive much more comprehensive data about Martian weather.

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Clouds

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

The Transfer of Water in Martian History

The unusual global geography of Mars helps to explain the fact that water has been drawn from the southern hemisphere to the northern hemisphere of the planet through all of Martian history (that is, from...more

Olympus Mons

The largest volcano in the solar system is Olympus Mons, shown in the image to the left. Olympus Mons is a Martian shield volcano. The altitude of Olympus Mons is three times the altitude of the largest...more

The Mariner Missions to Mars

Prior to the Mariner missions, we had to rely on ground-based observations to look at Mars. Using ground-based observations, scientists were able to identify channels, polar caps which varied with season,...more

Weather found by Mars Pathfinder

This is the first image showing clouds of Mars taken from the lander. Ground based viewing of Mars has shown that clouds seem to be plentiful only in the middle latitudes This may be because water of Mars...more

Mars Global Surveyor Measures Martian Surface Temperatures

This image shows how cold the surface of Mars can be. The temperature data is from the Mars Global Surveyor mission. The scale to the left shows that purple regions are the coldest, about -170 degrees...more

Martian Storm

This is an image of a storm moving across the Martian terrain. The camera is looking down upon the storm and the storm front forms a spiral pattern, the same way terrestrial storms are presented on the...more

Martian Surface Winds

The surface pressure of Mars is about 1/150th that of the surface pressure of the Earth. This means that there are much fewer molecules in the atmosphere. This means that the atmosphere near the surface...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF