WICHITA, Kan. (KSNW) — Our atmosphere can produce some amazing types of weather phenomenon in the troposphere, the lowest level of Earth’s atmosphere where we live. One key driver of the fascinating weather pattern on this planet is derived from the sun. The sun provides heat and energy that increases or decreases our temperatures daily and can charge our atmosphere for the development of storms. The sun can have far-reaching impacts outside of our tropospheric bubble. The study of these impacts revolves around space weather.
The study of space weather has nothing to do with rain and rumbles that occur in outer space. Instead, it focuses on the physics behind the sun, such as why the sun emits large solar flares, has sunspots, has solar cycles and how these things impact us here on Earth.
The outermost part of the sun is known as the corona. It is visible during a total solar eclipse, but must be viewed with proper eye protective coverings. Remember, looking directly at the sun is never advised as it can cause serious damage to your eyes.
The corona has extremely high temperatures. These high temperatures are the cause of ions moving so rapidly that they take on charges creating a strong magnetic field around the sun. Approximately every 11 years, the charges of the magnetic field around the sun change places from one pole to the next.
Scientists can keep track of this cycle by monitoring the number of sunspots on the surface of the sun. As solar activity increases, so will the number of sunspots. These sunspots are relatively cooler temperatures on the surface of the sun checking in around 6,500°F!
The magnetic field around these sunspots is much stronger and can cause things like solar flares and coronal mass ejections (CME) to occur. These eruptions can lead to bursts of solar wind which can travel at incredibly highs speeds between 800,000 and five million mph and vary in duration.
Scientists use satellite data to monitor the sun for these coronal mass ejections. If a CME was occurring in the image selected below, it would look like a thin white arc extending outward from the solid blue circle in the center where the lighter blue and white rays are extending outward.
If these eruptions on the surface of the sun are pointed in the direction of Earth, this can have significant impacts on our magnetic field that surrounds our planet. Events such as these are known as geomagnetic storms. Scientists can monitor solar activity to better prepare for impacts on Earth’s magnetic field. Geomagnetic storm watches and warnings can be issued if solar flares and CMEs look to impact Earth. At the end of October, a strong coronal mass ejection triggered a geomagnetic storm.
Using data such as the plasma density and velocity, scientists can forecast when a geomagnetic storm may have impacts for us here on Earth. In this instance, the effects of this geomagnetic storm occurred in early November. Geomagnetic storm watches and warnings were issued similarly to how weather watches and warnings work here in Kansas. The watch signaled that conditions were favorable for impacts here on Earth and the warning was issued once effects were felt.
This storm was considered a G3 storm meaning it was strong enough to lead to some disruptions, and it was able to produce the auroras as far south as the mid-latitudes. Some of the first places to feel these impacts were the top layers of our atmosphere where satellites are in orbit in the thermosphere. It is in this layer that we would also be able to see the auroras.
One of the more common impacts we typically think of associated with space weather is the appearance of the aurora borealis, also referred to as the northern lights, here in the Northern Hemisphere, closer to the polar regions. They can occur in the Southern Hemisphere as well, and there they are called aurora australis, or southern lights. There are forecasting products that are issued by the Space Weather Prediction Center that can help determine if the auroras will be visible and where that will be possible provided a clear sky is in place.
An index, known as the Kp Index, is used to measure geomagnetic activity over a period of time. Typically Kp values of 4 are required to see that faint green glow on the horizon. With more stunning northern lights shows, a Kp value of 7, or above, is required.
The ionosphere and thermosphere experience heating and expanding during these magnetic storms which can impact technology we use. Errors can occur in Global Positioning Systems (GPS). Radio communications can become altered or lead to blackouts. The orbits of satellites can shift. There is an increased level of radiation to high-altitude pilots and astronauts. This can also lead to stability issues on power grids.
As of this writing, we are currently working toward a solar maximum which is predicted to occur in July 2024. This means we may see more geomagnetic storms of varying strength and duration that could impact us on Earth. As activity increases the closer you get to a solar maximum in the sun cycle, solar flares and coronal mass ejections are more likely in the direction of Earth.
— Meteorologist Erika Paige