A storm on Mars shortened the winter in the southern hemisphere


Images of Mars in clear conditions (left) and during the 2018 Global Dust Storm (right).

Images of Mars in clear conditions (left) and during the 2018 Global Dust Storm (right).
EP

A dust storm that engulfed Mart in 2018 destroyed a vortex of cold air around the planet’s south pole and brought an early spring to the hemisphere. Rather, the storm caused only minor distortions in the polar vortex in the northern hemisphere and it did not cause dramatic seasonal changes, according to new research presented at the National Astronomy Meeting (NAM 2021) of the British Royal Astronomical Society.

For two weeks in early June 2018, localized dust storms combined and spread to form an impenetrable layer of dust that obscured almost the entire surface of the planet. The global dust storm, that coincided with the Mart’s equinoxand lasted until mid-September, it proved fatal to NASA’s Opportunity rover, which runs solar energy.

Dr. Paul Streeter and his colleagues from the Open University, NASA and the Russian Academy of Sciences examined the effects of the event on the Martian atmosphere combining data from a global climate model of Mars with data from the ExoMars TGO (Trace Gas Orbiter) of ESA / Roscosmos and MRO (Mars Reconnaissance Orbiter) of the POT.

“This was a perfect opportunity to investigate how global dust storms impact the atmosphere at the Martian poles, which are surrounded by powerful jets of wind in winter. Since the last global storm in 2007, several new missions and instruments have reached the orbit of Mars, making the 2018 event the most observed to date, “said Streeter.

Effect on temperatures and polar winds

Previous research has shown that high levels of dust in the atmosphere can have significant effects on temperatures and polar winds. The vortices at the winter poles also affect temperatures and the transport of air, dust, water and chemicals, so their alteration could mean substantial changes in the Martian atmosphere.

The team found that the 2018 storm had profoundly different effects in each hemisphere. At the south pole, where the vortex was nearly destroyed, temperatures rose and wind speeds dropped dramatically. While the vortex may have already begun to decompose due to the start of the spring, the dust storm appears to have had a decisive effect in ending the winter early.

The North Pole vortex, by contrast, was stable and early fall followed its usual pattern. However, the normally elliptical northern vortex was changed by the storm to become more symmetrical. Researchers link this to the high dust content in the atmosphere that suppresses atmospheric waves. caused by extreme topography in the Northern Hemisphere, which has volcanoes twice as high as Mount Everest and craters as deep as Earth’s mountains.

“Global dust storms at the equinox may improve transportation to the south pole due to the shrinking vortex, while eThe more robust northern vortex continues to act as an effective barrier. If this pattern of global dust storms persists over the thousands of years that Mars maintains this particular axial tilt, it has implications for how dust is deposited at the north and south poles and our understanding of the planet’s climatic history, “explains Streeter. .

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