Unprecedented Ultraviolet View of Mars Obtained

A new development in the MAVEN mission has shown an incredibly detailed ultraviolet glow from the Martian atmosphere. The pictures display dynamic behavior which was previously invisible, and shed light on how winds circulate at high altitudes. Dayside UV images display shifts in ozone amounts over various seasons and clouds which form over Martin volcanoes.

According to Nick Schneider of the Laboratory of Atmospheric and Space Physics at the University of Colorado, Boulder who said in a NASA news release, these are “some of the best high resolution ultraviolet coverage of Mars ever obtained.”

The two types of images show different characteristics. Nightside images show UV “nightglow” emission from nitric oxide. The term nightglow refers to a common planetary phenomenon in which the sky glows even without external light. On Mars, this is due to chemical reactions that initiate on Mars’ dayside. Winds bring the products of certain reactions to lower altitudes where atoms collide to form nitric oxide, and release energy in the form of UV light.

NO nightglow was a phenomenon predicted by scientists, but this is the first time NASA researchers have seen actual images of the phenomenon. Splotches and streaks are an indicated of where NO recombination is enhanced by winds and exemplify strong irregularities in Mars’ high altitude winds and circulation patterns.

The images will allow for improved determination of the circulation patterns that control the behavior of the atmosphere from approximately 37 to 62 miles (about 60 to 100 kilometers) high.

Dayside images show the surface and atmosphere close to the south pole in UV detail. They were captured when spring started in the southern hemisphere. Ozone is destroyed when water vapor is present, so ozone will accumulate in the winter polar region where the water vapor has frozen out of the atmosphere. The images display ozone lasting into spring, suggesting that global winds are inhibiting the spread of water vapor from the rest of the planet into winter polar regions. Wave patterns in the images, shown by UV absorption from ozone concentrations, are vital to understanding the wind patterns. This enables scientists to have an additional means to study the chemistry and global circulation of the atmosphere.

MAVEN images also display afternoon cloud formation over the four giant volcanoes on Mars, much as clouds form over mountain ranges on Earth. Clouds are important in understanding a planet’s energy balance and water vapor inventory. These images are thus helpful in understanding the daily and seasonal behavior of the atmosphere.

For more information, please visit: www.nasa.gov/

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