Auroras punched a 250-mile-wide in the ozone in Earth’s mesosphere, which resides 50 to 80 kilometers above Earth’s surface. Scientists captured the damage caused by an isolated proton aurora.
A research team that included scientists from Japan, Canada, and the United States say the aurora had more of an impact on the ozone than expected. This suggested at least one variable that the researchers hadn’t accounted for in their simulations.
The upper layers of Earth’s atmosphere, including the mesosphere, are constantly bombarded by solar radiation, cosmic rays, and high-energy plasma particles like ions and electrons. Electrons are frequently steered along magnetic lines by Earth’s magnetic field as they fall through Earth’s atmosphere. As they fall, they can ionize the upper atmosphere and create nitrogen oxides and hydrogen oxides. This does damage to Earth’s protective ozone layer.
The high-energy plasma particles are not easily observed, making it difficult to measure their impact on the upper atmosphere. Scientists do know that their interactions with the upper atmosphere can generate the isolated proton auroras. This type of aurora is often observable at lower latitudes than the more familiar “Northern Lights.” The aurora that researchers took a closer look at for this study was weaker than the Northern Lights typically are, but was still observable.
The research team could collect data from scientific instruments on the International Space Station, satellite remote sensing, and ground-based electromagnetic wave observations. The data revealed the hole in the ozone layer in the mesosphere. The damage did not extend to the more protective ozone layer in the stratosphere.
Up to 60% of the mesospheric ozone layer was destroyed within 90 minutes of the aurora’s appearance. However, scientists say that the damage quickly begain to repair itself when it was over.
The research team emphasized that their work could improve modeling of the ozone layer by providing a more clear picture of one of many variables that could lead to ozone depletion. The impact of the high-energy plasma particles were previously poorly understood.
“This study revealed that radiation belt electrons falling into the atmosphere from space around the Earth have a rapid and localized effect on the composition of the microatmosphere, including ozone. … This result strongly suggests that the influence of radiation belt electrons cannot be ignored in predicting changes in the Earth’s atmospheric environment,” the research team wrote in a statement announcing the results.
The research paper was published in Scientific Reports.
(Yes, holes in the ozone layer are a problem and some of the problem was caused by humans sending harmful chemicals into the atmosphere. However, NASA’s data suggests that the hole in the ozone layer over Antarctica is shrinking with reduced use of ozone-depleting CFCs.)