A new study involving weather and climate data collected from the various missions to Mars has determined that it does snow on the red planet, year round.
Previously both ground rovers and orbiting surveyor space craft had observed ice or frost on the surface of Mars and what appeared to be snow showers high above the surface, but it was believed that whilst snow formed high in the Martian atmosphere, it was so fine and the distance to the ground so great, and with very few natural forces to make it descend, it evaporated high above the surface.
However in the new study, the findings of which were published this week in the journal Nature Geoscience, researchers found that turbulent forces in the Martian atmosphere made it likely that powerful ‘down drafts’ could cause the high altitude snow to be pushed down to the surface before it had time to evaporate.
“There’s not enough to build a snowman,” says study co-author Aymeric Spiga, a planetary scientist at the French National Centre for Scientific Research who worked on the simulations of the Martian atmosphere on which the study was based. “Still, the snow is probably a substantial player in the planet’s water cycle,” he added.
In 2008 NASA’s Phoenix lander spotted wispy structures high overhead that looked a lot like virga streaks on Earth and scientists concluded that Phoenix had most likely seen a high-altitude snowstorm of water ice. Then in 2012 NASA’s Mars Reconnaissance Orbiter observed what looked like a cloud of carbon dioxide snowflakes over the southern pole.
A full guide to snow on other moons and planets, Snow In Space, has been published.