Water and pollution
After removing some effects generated by the local atmosphere, the researchers examined the spectrum of colors to see what molecules were visible. A few surprises popped up.
For example, they didn't see as much water vapor in the signature as observers saw in a 2009 eclipse that encompassed much of the Northern Hemisphere. (That paper, "Earth’s transmission spectrum from lunar eclipse observations," was published in the journal Nature.)
Another surprise was the abundance of nitrogen dioxide. Normally the nitrogen dioxide is regarded as a pollutant produced by human activities. The Antarctic, however, is quite a barren location — but it did have a volcano.
"We found that the track we observed is close to a volcano, and this volcano can potentially produce nitrogen dioxide," Yan said. [The Biggest Volcanoes on Earth]
He added that other explanations could be possible. In this case, the volcano (Mount Erabus) may not be active enough to produce large amount of nitrogen dioxide. Further investigation found that the nitrogen dioxide was a bio-product of nitrous oxide (which is produced naturally by microbes) that then lingered in the atmosphere and reacted with ozone, creating nitrogen dioxide.
"This was during the spring, and the ice melted in the spring, and according to the vulcanologists this melt releases a lot of nitrous oxide," Fosbury said.
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