Credit: Michael S. Helfenbein. Image courtesy NASA/JPL–Caltech
Scientists are preparing for crewed missions to distant planets and moons. They've recognized a need beyond rockets and rovers.
Accurate weather forecasts are essential. Without them, any trip up to the surface could be one step away from disaster.
Yale University has published a new study that helps to lay the groundwork for better, more accurate forecasts. It uses a phenomenon from Earth's jet stream to predict weather patterns on Mars, Titan, and Saturn's largest moon, Titan. Nature Astronomy published the study.
J. Michael Battalio is a Yale postdoctoral researcher in Earth and planetary science. He believes that the first accurate forecasts of Mars's days are only a decade away. It is simply a matter of combining more refined observational data with sufficient numerical models.
"But, until then we can rely on connections between climate and weather to help us anticipate dust storms."
Annular modea variability of atmospheric flow is what causes storm systems to occur in the middle latitudes on Earth. It is not related to the cycle of seasons. Annular modes have an impact on the jet stream, precipitation and cloud formations all over the globe. They account for up to one third of variability in wind-driven "eddies," such as blizzards and severe storm outbreaks throughout the Midwest.
Battalio was inspired to create the new study after noticing the similarity in the frequency of dust storms on Mars' Southern Hemisphere. After looking at 15 years worth of Mars atmospheric observations, Battalio discovered that Mars has the same annular modes as Earth.
Juan Lora, a Yale assistant professor of Earth-planetary sciences and Earth science, was Battalio’s lab supervisor. He suggested that they also search for annular modes on Titan. Lora developed the Titan Atmospheric Model, a highly respected global climate model that simulates the atmosphere for Titan.
Battalio & Lora discovered that annular modes were also prominent in their Titan simulations. Researchers found that annular modes are more important on Mars and Titan than on Earth. They are responsible for at least half the wind variability in Mars, and up to three-quarters in Titan.
Lora, coauthor of the study, said that methane clouds and surface changes due to methane rain on Titan had been seen before. These events may be linked to changes in Titan's strong jetstream, which is influenced by its annular mode.
Battalio added: "The fact we have found annular mode on worlds as distinct from Earth like Mars and Titan also suggests that they may be widespread in planetary atmospheres from Venus to the gas giants and exoplanets."
Mars' dust storms vary from small dust devils that occur constantly to large-scale dust storms that circle the planet every few years. While smaller storms may last for a few days, the larger global events can last several months. Regional events can also last from days to weeks.
Battalio stated that it is crucial to understand and predict these events for safety, especially for missions that rely on solar energy, as well for all missions landing on the surface. The dust can sometimes become so dense during larger regional events that it makes the day appear as dark as the middle night. Regional storms can occur even without large-scale, dramatic events.
Researchers believe that this periodicity could be used to predict dust storms by using annular modes. Each of the Earth's modes, Titan and Mars, occur on a regular basis. Real-time analysis allows for simple predictions of dust storms because the annular mode's impact on the eddies that create dust storms.
In 2004, the Opportunity robotic rover arrived on Mars for a 90-day mission. It operated for over 14 years partly by hibernating in dust storms. InSight, the robotic lander for Interior Exploration using Seismic Investigations and Geodesy (InSight), arrived on Mars in 2018.
Battalio stated that while a global event was what ended Opportunity's rover, the slow accumulation dust is currently threatening the survival of InSight.
Continue exploring Dust storms on Mars
Additional information: J. Michael Battalio et., Annular modes in variability in the atmospheres Mars and Titan, Nature Astronomy (2021). Information from Nature Astronomy J. Michael Battalio and colleagues, Annular modes in variability in the atmospheres Mars and Titan (2021). DOI: 10.1038/s41550-021-01447-4