American Geophysical Union | 2020 Jan 29
A new type of aurora called “the dunes” discovered by aurora chasers in Finland is helping scientists better understand a mysterious layer of Earth’s atmosphere.A New Type of Aurora Named 'The Dunes'Click to play embedded YouTube video.
Credit: Kari Saari/Minna Palmroth/Lauren Lipuma (AGU)
Music: Lullabye by Density & Time
The aurora – nighttime light displays in the atmosphere near Earth’s poles – take on various shapes and forms. They often appear as rippling curtains of green, red, or purple light. But in October 2018, amateur auroral photographers in Finland discovered a new auroral form they dubbed “the dunes.”
The dunes appear as thin ribbons of green light in the sky, extending toward the equator for hundreds of kilometers. Most auroral light displays are oriented vertically, like curtains hanging down from the sky, but the dunes are arranged horizontally, like fingers reaching toward the horizon. ...
The researchers suspect the dunes are visible manifestations of undulations of air called atmospheric waves. If their theory proves correct, the dunes could provide a way to understand a part of Earth’s upper atmosphere that is notoriously difficult to study. This region of the atmosphere, roughly 80 to 120 kilometers (50 to 75 miles) about Earth’s surface, is sensitive to changes in energy from the Sun and Earth’s lower atmosphere. Energy fluctuations in this region can indirectly affect the trajectories of Earth-orbiting satellites and spacecraft reentry. ...
Citizen scientists discover a new auroral form: Dunes
provide insight into the upper atmosphere ~ M. Palmroth et al
- AGU Advances 1(1):2019AV000133 (28 Jan 2020) DOI: 10.1029/2019AV000133