While the night sky with the reflection of the “northern lights” or aurora borealis has attracted the attention of scientists and sky watchers for centuries, little is known about the carbon dioxide-related aurora borealis. In a new study published in the journal Geophysical Research LettersScientists have published global observations of the aurora borealis bound to carbon dioxide using satellite measurements.

When we think of the aurora borealis, we often imagine dazzling green and red lights dancing across the sky. However, the aurora borealis has a large number of associated emissions that occur in different parts of the atmosphere, most of which are invisible to the human eye.

Earth’s atmosphere consists of several layers. In the troposphere, we experience most of the air on Earth. The next layer, the stratosphere, contains the Earth’s ozone layer, which protects us from the sun’s harmful ultraviolet radiation. The middle layer is the mesosphere, where meteorites burn as they collide with the rapidly increasing density of Earth’s atmosphere. Above this layer is the thermosphere, which is located 80 to 700 km above the Earth’s surface and overlaps with the ionosphere, the part of the atmosphere filled with charged ions and electrons.

Near the bottom of the thermosphere, at an altitude of about 100 km, is the “edge of space”, also known as the Kármán line. The Karman line shows the altitude at which the satellites can orbit. A lot of polar radiation occurs in the thermosphere and ionosphere of the Earth’s atmosphere. Commonly observed green and red auroras occur at altitudes of about 100 km and 250 km, respectively, due to the excited state of atomic oxygen.

When energetic particles strike Earth’s atmosphere, they interact with a mixture of atoms and molecules. One such molecule is carbon dioxide. Although carbon dioxide is known for its effect on the troposphere as a greenhouse gas, it is also present in trace amounts in the Earth’s atmosphere at the edge of space.

About 90 km (56 miles) above Earth, carbon dioxide begins to fluctuate during the aurora borealis, emitting more infrared radiation than is normally seen in the atmosphere.

Lead author and Arizona State University scientist Katrina Bossert and an international research team used the Atmospheric Infrared Sounder, which collects infrared energy emitted from the Earth’s surface and atmosphere each year, to observe the increased infrared signals from carbon dioxide during the auroras. day. Its data provides three-dimensional measurements of temperature and water vapor in the atmospheric column, and a range of trace gases, surface features, and clouds aboard NASA’s Aqua satellite.

An international scientific team has observed an increase in infrared signals from carbon dioxide during the auroras. This work of isolating emissions provides a dataset for future studies of the northern lights and the fallout of energetic particles around the world.

“This offers a new way to observe Earth’s aurora from space. “Different auroral emissions can be correlated with different heights and energies of particles,” said Bossert, an associate professor in ASU’s School of Earth and Space Studies and the School of Mathematical and Statistical Sciences. “Auroral carbon dioxide emissions occur slightly lower than the normal orbits of satellites, in a region we think of as the edge of space. The observations can provide insight into the physical processes associated with the aurora.”

Although it was previously known that carbon dioxide could be induced during the aurora borealis, this dataset and analysis method provides the first daily global observations of the Northern and Southern Hemisphere regions using a rare imaging satellite. Satellite measurements span over 20 years and can be used for future studies of aurora and interactions of energetic particles with Earth’s atmosphere. Source