Temperature differences spawned this storm at Mars’s north pole
LARGE dust storms on Mars might have far-reaching effects. They can affect the entire atmosphere, possibly seeding new weather systems that can combine to form planet-wide storms unlike anything we see on Earth.
Advertisement
Dust storms are not uncommon on Mars. Local ones are those that cover an area less than 100,000 square kilometres – roughly half the size of the UK – and these occur several hundred times every year, although they last less than a Martian day. Regional ones can be as large as 1 million square kilometres – roughly the size of Alaska – and happen a dozen times every year. They are also more persistent.
Global storms blanket Mars in a thick haze and can last for hundreds of days. Luckily these only come about every three to four Martian years. But how do they form?
“That is one of the great unanswered questions,” says at Johns Hopkins University in Maryland. Should researchers find out, they might be able to forecast these mega-storms. That could in turn help ensure the safety of rovers and future astronauts alike.
Toigo and his colleagues applied a weather model designed for Earth to Mars, simulating several local and regional storms. They wanted to study how those affect the atmosphere elsewhere on the planet and test a long-standing prediction: that smaller storms cascade into larger ones.
“Future human colonies will need to worry about distant regional storms as well as local ones”
The team found that local storms have little to no effect on the atmosphere beyond their borders, so probably do not swell up into anything more menacing.
Regional storms, on the other hand, especially ones that last for more than a few days, can boost winds or raise the temperature far from their location. The increased dust absorbs more sunlight and heats the atmosphere, driving large-scale dynamics across the planet, similar to how heating at Earth’s equator causes the jet streams. Such changes might create spin-off storms across Mars and could explain how regional storms combine to form global ones (Icarus, ).
“Regional dust storms occur with some frequency on Mars – so the fact that they can influence the global atmospheric condition on Mars is pretty striking,” says Brian Jackson at Boise State University in Idaho. That could mean that future human colonies will need to worry about distant regional storms as well as local ones.
Although dust storms are nowhere near as damaging as the one depicted in the film The Martian, they produce enough static electricity to short-circuit electronics. They also leave enough dust in the atmosphere to hinder solar energy generation.
That’s a big concern for Jennifer Herman, the power subsystem operations team lead for the Opportunity rover at NASA’s Jet Propulsion Laboratory in Pasadena, California. And it’s not her only worry. Once storms dissipate, the dust rains down on the rover’s solar panel, blocking the sun’s rays until cleared away by the wind. “It’s kind of like a double whammy,” Herman says.
The last global dust storm on Mars happened in 2007, so one is overdue. Some scientists speculate that the next one will occur in 2018, although Toigo points out that this is a statistical guess. He says his study and others will help better forecast when the next mega Martian dust storm may hit.
This article appeared in print under the headline “Mars storms snowball and can turn humongous”
