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What kinds of clouds form in the atmosphere of Mars?
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Mars
An especially serene view of Mars (Tharsis side), a composite of images taken by the Mars Global Surveyor spacecraft in April 1999. The northern polar cap and encircling dark dune field of Vastitas Borealis are visible at the top of the globe. White water-ice clouds surround the most prominent volcanic peaks, including Olympus Mons near the western limb, Alba Patera to its northeast, and the line of Tharsis volcanoes to the southeast. East of the Tharsis rise can be seen the enormous near-equatorial gash that marks the canyon system Valles Marineris.
Despite the low water content in the Martian atmosphere, it remains near saturation, making water-ice clouds a common feature on Mars. These clouds take several forms:1
- Water-ice clouds: Most clouds observed on the planet, including the white clouds noted by early astronomers, are composed of water ice.1
- Low-lying clouds and fogs: These are frequently observed within topographic depressions, such as craters and valleys.1
- Morning clouds: Thin clouds often appear at the morning terminator, which is the line dividing the lit and unlit portions of the planet.1
- Orographic clouds: These form when moist air is lifted over elevated terraināsuch as volcanoes and cratersāand subsequently cools.1
Additionally, while not classified as clouds in the traditional sense, dust storms and dust devils are significant atmospheric phenomena on Mars. During the winter, spiral-shaped storm systems are also regularly observed at midlatitudes.1