(ORDO NEWS) — The image below shows the Martian Mount Arsia, which is a long-extinct volcano, and an orographic cloud hovering over it with a length of about 1,500 kilometers.
Clouds are common in this region of the Red Planet, but it was this massive atmospheric formation that appeared out of season.
Clouds usually form over Mount Arsia when Mars is farthest from the Sun (local summer) because the atmosphere is colder (closer to the water condensation point) and the northern ice cap supplies enough water vapor to it.
However, this long band of clouds formed as Mars approached the Sun. These non-seasonal long clouds appear over Arsia around the same time of the Martian year, due to the delicate balance of local climatic conditions.
Fragile Martian balance
- As we approach the Sun, the summer equinox begins at the south pole of Mars, the atmosphere becomes denser and more saturated with moisture
- The atmosphere in the region of Mount Arsia, as the planet approaches the Sun, receives additional heat
- The next stage of the approach of Mars to the Sun leads to the fact that dust begins to rise in the southern hemisphere, which ensures the effective condensation of fine water particles (the southern Martian spring/summer is known to be dusty – almost all global dust storms ever observed began in this time period). interval)
- With each sunrise, westerly winds begin to blow in the region, which push the “air” up the eastern slope of Mount Arsia. The mountain is over 20 kilometers high, so the water condenses as the “air” rises and cools
These conditions are in equilibrium only during 30-60 days of the Martian year. Prior to Mars’ approach to the Sun, the “air” is too dry because the southern ice cap hasn’t released enough water.
When the planet is close (relatively) to the Sun, Mars becomes too warm for water to condense.
Without dust, which lowers the temperature of the atmosphere and creates a condensation center, these conditions may not be satisfied for long or not at all.
The natural color image attached to the top of this article was taken by the European Space Agency (ESA) Mars Express on September 21, 2018.
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