Nitrogen, oxygen and water vapor molecules are broken apart by lightning and associated weaker electrical discharges, generating the reactive gases NO, O3, HO2, and the atmosphere’s cleanser, OH. IMAGE: JENA JENKINS
UNIVERSITY PARK, Pa. — Lightning bolts break apart nitrogen and oxygen molecules in the atmosphere and create reactive chemicals that affect greenhouse gases. Now, a team of atmospheric chemists and lightning scientists have found that lightning bolts and, surprisingly, subvisible discharges that cannot be seen by cameras or the naked eye produce extreme amounts of the hydroxyl radical — OH — and hydroperoxyl radical — HO2.
The hydroxyl radical is important in the atmosphere because it initiates chemical reactions and breaks down molecules like the greenhouse gas methane. OH is the main driver of many compositional changes in the atmosphere.
“Initially, we looked at these huge OH and HO2 signals found in the clouds and asked, what is wrong with our instrument?” said William H. Brune, distinguished professor of meteorology at Penn State. “We assumed there was noise in the instrument, so we removed the huge signals from the dataset and shelved them for later study.”