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Our next planet Mars in 2016, NASA / ESA's Hubble Space Telescope. Credit: NASA, ESA, Hubble Heritage Team (STScI / AURA), J. Bell (ASU) and M. Wolff (Institute of Space Science)
New research using a decade of data from Mars ESA Express of the complex Martian atmosphere acting as a single interconnected system, with processes occurring at low and medium levels significantly affecting those seen above.
Understanding the Martian atmosphere is a key topic in planetary science, from its current status to its past history. The atmosphere of Mars continuously escapes to space, and is a crucial factor in the past, present and future habitability of the planet – or its lack. The planet has lost most of its formerly much denser and wetter atmosphere, causing it to evolve into the dry and arid world we see today.
However, the tenuous atmosphere that Mars has retained remains complex, and scientists are trying to understand and how its processes are connected in space and time.
A new study based on 10 years of radar instrument data on Mars Express now offers clear evidence of a desired link between upper and lower system atmospheres. planet. Although known to have probed the interior of Mars by radar sounding, the instrument also collected observations of the Martian ionosphere since its inception in 2005.
"The lower and middle levels of The atmosphere of Mars seem to be coupled to levels: there is a clear link between them throughout the Martian year, "says lead author Beatriz Sánchez-Cano of the University from Leicester, United Kingdom
"We found this link by tracking the amount of electrons in the upper atmosphere. this has been measured by the MARSIS radar for more than a decade across different seasons, areas of Mars, hours of the day and more – and correlated with the atmospheric parameters measured by other instruments on Mars Express . "
Credit: ESA / Mars Express / MARSIS / B. Sánchez-Cano et al 2018
The amount of charged particles in the upper atmosphere of Mars – at altitudes between 100 and 200 km – is known to change with the season and local time, driven by changes in solar illumination and activity crucial for this study, the variable composition and density of the atmosphere itself. " We have discovered a surprising and significant increase in the amount of charged particles in the upper atmosphere in spring in the northern hemisphere, that is, when the mass in the lower atmosphere increases. as the ice sublimates from the northern polar cap, "adds Beatriz
the polar ice caps of Mars consist of a mixture of ice water and frozen carbon dioxide. Each winter, up to a third of the mass of the Mars atmosphere condenses to form a layer of ice at each of the poles of the planet. Each spring, some of the mass inside these caps sublimates to reach the atmosphere, and the caps visibly shrink.
"It was thought that this process of sublimation mainly affected the lower atmosphere – we did not expect to see its effects propagating clearly to higher levels," says Olivier Witasse, co-author of the Agency European space, and former ESA scientist for Mars Express
"It is very interesting to find a link like this, suggests that the atmosphere of Mars behaves like a single system
This could help scientists understand how the atmosphere of Mars evolves over time – not only with respect to external disturbances such as space time and the activity of the Sun. With regard to the strong Mars internal variability and surface processes
Mars Express artist print.The bottom is based on a real Mars image taken by the high resolution stereo camera from the spacecraft. Spac ecraft image credit: ESA / ATG medialab; March: ESA / DLR / FU Berlin
Understanding the complex atmosphere of Mars is one of the key objectives of ESA's Mars Express mission, which operates in orbit around the red planet since 2003.
"Mars Express is still," says Dmitri Titov, researcher at ESA's Mars Express project
"Having a long baseline, it's one of Its current main goals are to explore exactly how the Martian atmosphere behaves and how its different layers are connected to each other.Data is fundamental to our study of Mars – there is now more than a decade These data not only cover a long time, but also the whole of Mars and its atmosphere.
"This wealth of complete and complementary observations by different instruments on Mars Express makes possible studies like this and, with the Trace Gas Orbiter and NASA's MAVEN mission, help us unlock the secrets of the Martian atmosphere. "
" Spatial, Seasonal and Solar Cycle Variations in Total Martian Electron Content (TEC): Is the TEC a Good Atmosphere Tracer? cycles? By Sánchez-Cano et al. is published in the Journal of Geophysical Research.
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