Scientists reveal first global map of Mars’ wind patterns

Credit for this article goes to E&T

Global wind patterns on Mars have been mapped out for the first time by scientists who have been studying the Red Planet’s upper atmosphere.

To carry out the investigation, the team remotely re-programmed Nasa’s MAVEN spacecraft, which has been in orbit around Mars since 2013, in order to capture the data needed for the study.

Researchers from the University of Maryland Baltimore measured the atmosphere for two days per month over the course of two years from 2016 to 2018.

As a result, the team found that the circulation patterns of the winds in the upper atmosphere were varying stability from season to season. However, that wasn’t the case for shorter-term winds.

“On Mars, the average circulation is steady, but if you take a snapshot at any given time, the winds are highly variable,” said Mehdi Benna, a planetary scientist at Nasa and the University of Maryland. “More work is needed to determine why these contrasting patterns exist.” 

The global map of the Red Planet’s wind patterns also indicated “ripple effects” from the extreme terrain below.

Computer-generated visualisation of the orbital paths (white dots) taken by the MAVEN spacecraft
Computer-generated visualisation of the orbital paths (white dots) taken by the MAVEN spacecraft as it mapped winds (blue lines) in the Martian upper atmosphere. Red lines coming from the white dots represent local wind speed and direction, measured by MAVEN’s Neutral Gas and Ion Mass Spectrometer instrument

As the wind sails nearly 190 miles (300km) above the Red Planet’s surface, the team saw changes caused by the Martian landforms below, including mountains, canyons and basins.

A similar effect occurs on Earth, however, the team said they found something unexpected about the effect on Mars, with Benna stating: “On Earth, we see the same kind of waves, but not at such high altitudes. That was a big surprise.”

The researchers suggested two explanations for why this might be happening. Firstly, they theorised that Mars’ atmosphere is much less dense than Earth’s, so these “orthographic waves” might be able to move farther on the Red Planet, just as ripples travel farther in water than they do in molasses (black treacle).

Benna also explained that the second possible factor is that there is a bigger average altitude difference between peaks and valleys on Mars than there is on Earth, especially because many mountains on the Red Planet are twice as high as Mount Everest (which stands roughly 5.5 miles, or 9km).

“The topography of Mars is driving this in a more pronounced way than it is on Earth,” Benna said.

Throughout the investigation, the team documented the global wind circulation patterns on Mars at 75 to 190 miles (120 to 300km) above the surface, using local observations.

To achieve this, the researchers reprogrammed an instrument called the Natural Gas and Ion Mass Spectrometer (NGIMS) on the Mars Atmosphere and Volatile Evolution (MAVEN) orbiter, created by Nasa, to “swing back and forth like a windscreen wiper” rather than staying still.

As a result, the team managed to convince the space agency to make the necessary changes and were able to begin collecting data the same year.

Benna added that the team plan to continue analysing the data from the study as they believe it will help them determine whether the same basic processes are in action in Earth’s upper atmosphere.

“Ironically, we had to go take these measurements on Mars to eventually understand the same phenomenon on Earth,” said Benna. “Ultimately, the results will help us understand the climate of Mars. What is its state and how is it evolving.”

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