A new study published in journal Nature Geoscience has suggested that Mars is buffeted by turbulent snowstorms that occur only at night and that the ice-water particles swirling in a storm hit the ground within minutes, rather than descending gently for hours.
It has been believed until now that snow falling from low-lying Martian clouds settled slowly and sparsely to the ground in a environment bereft of violent winds. However, the new study suggests the contrary.
While the snow may fuel hopes for winter sports on Mars, scientists say that’s not going to be the case because it is mostly dry ice and not the water ice that we humans are used to. If you are on Mars, you wouldn’t see a thick blanket of snow, but rather will be greeted with a layer of frost – conditions that are not ideal for winter sports.
The atmosphere of Mars is 100 times thinner than Earth’s, though still thick enough to support weather, including clouds and wind. But there’s very little moisture. Indeed, the Red Planet is essentially a bone-cold desert with virtually no liquid water on its surface.
In the Martian arctic, however, water ice lurks just under a layer of dust. This was detected up close by NASA’s Phoenix lander, which scraped below the planet’s surface with a shovel in 2008. The stationary robot lab also analysed local weather, detecting signs of precipitation below water-ice clouds. A pair of orbiting satellites also picked up clues suggesting night-time weather, especially over the northern polar region. Both observations perplexed scientists at the time.
To probe further, authors of the new study devised a new atmospheric model to simulate weather on Mars, based on more fine-grained data. Cooling of water-ice cloud particles during the cold Martian night, they found, can create unstable conditions in clouds. Scientists were able to show through their model that precipitation of snow below the clouds is transported by very violent, descending winds, which are akin to small, localised weather phenomena on Earth called microbursts.
The Martian atmosphere is 95 percent carbon dioxide (also present as frozen dry ice), along with two percent each argon and nitrogen, with trace amounts of oxygen, nitrogen oxide, neon, and krypton. A whispy atmosphere and its greater distance from the sun make Mars very cold, with an average temperature of 63 degrees Celsius (minus 76 degrees Fahrenheit). Earth, by comparison, is a balmy 16 C (61 F).