New map of Mars' upper atmosphere shows wind patterns on the Red Planet are much simpler than those on Earth
This will help scientists better understand the workings of the Martian climate, giving them a more accurate picture of its ancient past and its ongoing evolution
Winds circulating high above Mars' surface holds clues to understanding how the Red Planet lost the thick atmosphere that it once enjoyed. So far, we do not know a lot about what caused it.
Bringing us one step closer towards unraveling this mystery is a new study that maps Mars' upper atmosphere. The latest data shows that Mars' wind circulates in simpler ways than on Earth, in patterns that linger or remain stable over varying seasons.
"This is like saying that on the East Coast of the US, throughout the year, weather systems generally flow from the West to the East in a predictable way," says study authors.
The new map of Mars' upper atmospheric winds will help us better understand the workings of the Martian climate, giving us a more accurate picture of its ancient past and its ongoing evolution, say authors of the study.
Studying Mars' wind patterns is important as its atmosphere continues to thin. "Atmospheric escape [of gases] at Mars takes place through the outermost layer of its atmosphere – the thermosphere," Mehdi Benna, a Planetary Scientist at NASA and lead author of the study, tells MEA WorldWide (MEAWW).
"To understand the inner workings of the loss process, one needs to characterize not only the composition of this upper layer of the atmosphere but also how it distributes around the planet," Benna shares.
The study builds on data collected from MAVEN — the spacecraft which has been exploring the tenuous upper atmosphere of Mars, since 2014.
"These are truly special observations. MAVEN and the NGIMS – the Neutral Gas and Ion Mass Spectrometer – were not designed to carry over this type of observation."
"It took a lot of clever 'remote reengineering' to operate the spacecraft and the instrument in a manner that made these measurements possible. The collected data turned out to be a very rich data set that would keep scientists busy for years," Benna adds.
To map the atmospheric circulation, MAVEN dived into the Martian upper atmosphere, measuring wind patterns at roughly 140-240 kilometers above the surface. By capturing molecules in the wind, the instruments aboard the spacecraft analyzed them, informing scientists about the speed of wind flow.
Besides concluding that Mars' wind patterns are simpler than what we see back home, scientists also found that the wind hundreds of kilometers above the planet's surface held information about landforms below, like mountains, canyons, and basins.
This indicated that, in some locations, information from the surface traveled vertically to the upper atmosphere, in the form of mountain waves. "On Earth, we see the same kind of waves, but not at such high altitudes. That was a big surprise, that these can go up to 280 kilometers high," says Benna.
This could be due to two reasons. First, Mars has a thinner atmosphere than Earth, which allows these waves to travel longer distances.
Second, the peaks on Mars are a lot higher, with some of them standing 20 kilometers tall, in comparison Mt. Everest which is not even nine kilometers tall, and most peaks on Earth are much shorter. These findings could also provide insights on Earth's upper atmosphere.
"Since the physics that is in play in the extraterrestrial atmosphere of Mars is similar to that controlling the Earth’s atmosphere, the knowledge that is being gained from these measurements will ultimately serve to further our understanding of the processes that drives our atmosphere and climate at Earth," Benna adds.