Mars has snowstorms at night

A Martian meteorology study reveals rapidly falling snow above the planet’s surface.

Although Mars has very little water vapor in its atmosphere, ice clouds can still form above the red planet. Now, new research finds that these clouds unleash rapidly falling snow at night. One of the study’s authors, Franck Montmessin, tells us more about the dramatic snowstorms on Mars.

ResearchGate: How do these storms compare to other weather conditions on Mars?

Franck Montmessin: There are various types of storms on Mars. The most famous are dust storms, made of mineral particles lifted from the ground. We report a different type of storm, made of water ice particles. Other studies have pointed to the existence of CO2 ice snow storms in the deep polar night of Mars, but no water ice storm has ever been suggested to exist on Mars until now.

RG: What are the snowstorms like?

Montmessin: Most of the time, Martian cloud particles evaporate before they reach the surface, like virgas on Earth. Water-ice cloud particles form during the cold Martian night. Because they are able to cool the surrounding atmosphere—by losing heat through the emission of infrared radiation—they can lead to cold air over warmer air within the cloud. This unstable condition triggers a descending plume of snow. These turbulent storms, which can only form at night, act to vigorously mix the atmosphere, and in some places, deposit snow on the Martian surface.

We propose that Martian snowstorms are analogous to small localized storms on Earth called microbursts, in which cold dense air carrying snow or rain is rapidly transported downwards from a cloud.

Nature Geoscience. Published online: 21 August, 2017.

RG: How did you determine that they happen?

Montmessin: Through a combination of numerical simulations performed with a Mars weather model, which are supported by temperature profile observations from previous missions. There has been no direct observation of a water ice snow storm, which I’m sorry to say means no pictures! But the predictions performed by the model show their existence, and this is corroborated by temperature measurements.

Also, some clouds were observed close to the surface of the Martian north pole by the Phoenix mission, and while their discoverers initially suggested a different type of cloud formation, our article shows that they could also be explained by a local snow storm.

RG: Does this have implications for any future missions to Mars?

Montmessin: Well, the associated winds found in the storm are rather vigorous. Since they occur in the lower part of the atmosphere, one might want to avoid these turbulent events to ensure a safe landing.

 



Featured image: Carbon dioxide ice on the surface of Mars. Courtesy of  ESA/DLR/FU Berlin (G. Neukum), CC BY-SA 3.0 IGO.