Do solar storms influence Martian weather? New study finds evidence that dust storms get affected

When solar storms coincide with Martian dust storms, they may warm the Red Planet's lower atmosphere, a new study reveals. Astronomers from Lancaster University, the University of Leicester, and the Instituto de Astrofísica de Andalucía-CSIC in Granada, Spain, have found evidence that the planet's lower atmosphere warmed during one such combined event in June 2018. The discovery, presented this week at the Royal Astronomical Society's National Astronomy Meeting in Birmingham, could change how scientists understand weather on Mars and improve future climate models of our neighboring world.

Solar flares and coronal mass ejections unleash energetic particles, triggering solar energetic particle (SEP) events. Previous research has shown that SEP events affect the Red Planet’s upper atmosphere, triggering auroras, ionizing atmospheric gases, and disrupting the propagation of radio signals. But could these phenomena affect the lower atmosphere? To find the answer, the team analyzed five SEP events. They compared temperature predictions from the Mars Climate Database with data from NASA's MAVEN spacecraft and the European Space Agency's Trace Gas Orbiter, aiming to determine whether the solar events produced any measurable warming.

"We expected that these highly energetic particles might have some effect on temperatures in Mars' lower atmosphere,” said lead researcher Lana Williams, a PhD researcher at Lancaster University, in a statement. Four of the SEP events didn’t leave any measurable effects, but the fifth did. It occurred in June 2018, coinciding with a global dust storm that blanketed Mars. (This was the same massive storm that blocked sunlight and permanently ended the mission of NASA's Opportunity rover). "The one exception occurred while a global dust storm was expanding across the planet," Williams added.

The researchers detected that the lower atmosphere showed signs of warming unlike anything seen during the other solar events. While a single observation cannot definitively prove that an SEP event influences Martian dust storms to warm the lower atmosphere, such a combination warming the Red Planet’s lower atmosphere has not been previously explored. While dust storms absorb sunlight and warm parts of the planet's atmosphere, the dust storm alone was not responsible for the specific pattern of heating observed in 2018. Instead, the researchers detected evidence suggesting that the solar particles and the dust storm may have interacted, producing an atmospheric response that neither phenomenon would have caused independently.

"Dust storms were not originally part of our investigation, so finding one happening at the same time as the heating was unexpected,” said Williams. “It suggests that Mars' atmosphere and weather may respond to several events acting together, rather than each source of heating operating independently." Although more observations are needed, the latest research suggests that Mars’ weather may also be driven by a delicate partnership between the Sun and the planet itself.

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