ionosphere

Alouette I ionogram data

Launched in 1962, Alouette I sent radio waves of different frequencies into the topmost layer of the atmosphere, known as the ionosphere, and collected data on the depth of penetration of these waves. The results of this were sent to ground stations around the world and stored on films, a portion of which have now been digitized. These data were used to fuel hundreds of scientific papers at the time. Although ionosphere data derived from inversions and this dataset are readily available, the raw data from Alouette I’s ionograms allow for further studies due to scientific advancements since they were acquired. In the past, accessing this data was difficult, which limited its use, interpretation, and analysis on a larger scale.

Fun Facts About the Ionosphere

It’s home to all the charged particles in Earth's atmosphere

Earth’s ionosphere overlaps the top of the atmosphere and the very beginning of space.

The Sun cooks gases there until they lose an electron or two, which creates a sea of electrically charged particles.

It's home to many of our satellites

This boundary to space is right where many of our Earth-orbiting satellites hang out, including the International Space Station.

That means these satellites can be affected by the constantly changing conditions in the ionosphere — including sudden swells of charged particles that increase drag on satellites and shorten their orbital lifetimes, or how long they can continue orbiting Earth.

It’s influenced by space weather

Because the ionosphere is made up of charged particles, it's uniquely reactive to the changing magnetic and electric conditions in space. These conditions — along with other events like bursts of charged particles — are called space weather and usually connected to solar activity. Along with regular weather from here on Earth, space weather is the other major factor that impacts the ionosphere.

The ionosphere constantly glows

Airglow is what we call the bright swaths of light that shine from Earth's upper atmosphere. It happens when atoms and molecules in the upper atmosphere, excited by sunlight, emit light to shed their excess energy. Or, it can happen when atoms and molecules that have been ionized by sunlight collide with and capture a free electron. In both cases, they eject a particle of light — called a photon — in order to relax again. Airglow isn't just a beautiful sight: It's a useful marker for what happens in the ionosphere. Each atmospheric gas has its own favored airglow color depending on the gas, altitude region, and excitation process, so we can use airglow to study where these gases are and how they behave.

Page updated

Report abuse