GOLD Level 2 data showing the temporal and spatial evolution of the thermosphere during the storm on 11 May. The first and second rows are the 1356 Å and LBH absolute radiances used as input to the ΣO/N2 algorithm, while the last two rows show the GOLD ΣO. /N2 and TDISK values. The full disk images shown are individual northern and southern hemisphere scans. The times listed at the top of each row are the times the Northern Hemisphere scan began. Scan starting at 08:10 UT, minimum daytime data not shown. The black line represents the geomagnetic equator. – Geophysical Research Letters
On May 11, a beautiful aurora dazzled stargazers across the southern United States. That same weekend, the GPS-guided tractor missed its mark.
What does visibility of the northern lights have in common with compromised farm equipment in the Midwest?
A uniquely powerful geomagnetic storm, according to two newly published papers co-authored by Virginia Tech’s Scott England.
„The Northern Lights are caused by energetic, charged particles hitting our upper atmosphere, which are affected by many factors in space, including the Sun,” said Kevin D. England, associate professor in the Grafton Department of Aerospace and Ocean Engineering, said. „During solar geomagnetic storms, there’s a lot of these energetically charged particles in the space around Earth, so we see the Northern Lights brighten, and they spread out over an area where you can see them to include places like the lower 48 states. You don’t normally see this display.
A team of UK and university and industry collaborators monitored the upper atmospheric event on May 11 using NASA’s GOLD instrument. It is the strongest geomagnetic storm captured in the past 20 years. Their findings were recently published in Geophysical Research Letters in two studies, both co-authored by England. The first study, by first author Deepak Karan of the University of Colorado, Boulder, showed unprecedented changes in the location and distribution of particles in the upper atmosphere. In the second study, first author and Virginia Tech alumnus J. Scott Evans ’88, documented changes in composition and temperature.
Among the data collected, England noted that for the first time some „exciting vortex patterns” were observed, and the dramatic movement of air from the aurora created enormous eddies that moved the air in a vortex larger than a hurricane. Specific observations include:
- The unpredictable movement of low-energy charged particles from around the equator towards the aurora
- Charged particles can be divided into two buckets: low-energy and high-energy, the latter of which can harm humans and damage electronics.
- Changes in temperature and pressure lead to eddies and eddies
- Changes in the locations and distribution of low-energy particles that negatively affect GPS, satellites, and even the power grid
„As the aurora intensifies, you see more lights, but with that, more energy enters the atmosphere, so it warms the atmosphere near the poles more, which starts to push air away from the poles and toward the equator,” England said. „Did something different happen during this geomagnetic storm than before, or do we have better tools to measure the changes?” This data raises several questions such as
And what do those changes mean for man-made technology orbiting that part of the atmosphere?
The Northern Lights are more than they show
Earth’s upper atmosphere, extending from about 60 to 400 miles above us, borders outer space and is the hang-out zone for satellites and the International Space Station. The upper atmosphere is made up of some of the same particles as the lower atmosphere in which we live and breathe. But it also has another side, the ionosphere is almost like an electric blanket – highly charged and constantly fluctuating. These charged particles in the ionosphere are one thing that makes this region of space so energetic. Changes in temperature and composition of the upper atmosphere and ionosphere are common. In fact, it does so predictably during the day and night and even changes overtime with the seasons.
Particles in the Earth’s atmosphere are affected by many factors in space, including the activity of the Sun, England said. During a solar geomagnetic storm burst, an intense burst of radiation from the Sun changes the composition and velocity of particles in Earth’s atmosphere. Why have the northern lights been seen in places around the world in recent months that have never been seen before?
„The number of sunspots, flares and storms changes in an 11-year cycle, which we call the solar cycle,” England said. „The number of flares we see has been steadily increasing over the last couple of years as we head towards the peak of the solar cycle.”
In addition to the sighting of the Northern Lights, geomagnetic storms have many different effects on our technology. Because radio and GPS signals travel through this constantly fluctuating „electric blanket,” changes in this layer of the atmosphere disrupt the signals and disrupt communication systems such as navigation and GPS. A variety of factors from both Earth’s weather and space weather can affect this critical layer, but much remains to be learned about why changes in the upper and lower atmosphere occur and how they can affect life as we know it.
„These storms can increase the currents that flow around the Earth, which can affect technical devices that use very long wires. In recent years, high currents flowing through power lines have caused damage to the power grid. During the Carrington Event, the largest geomagnetic storm ever recorded in 1859, „These telegraph systems — state-of-the-art at the time — fueled the fire,” England said.
Scientists suspect that if a storm like the 1859 Carrington event happened today, it could cause a cyber disaster, sending scores of people and businesses offline. Although the May 11 storm did not cause serious disruptions, and is expected to peak in the solar cycle in July 2025, we are still a year away from knowing those potential effects.
„One of the reasons we study geomagnetic storms is to try to develop models to predict their impacts,” England said. „Based on the solar cycle, we expect the conditions we’re seeing this year to be there for the next couple of years.”
Gold observations of the thermospheric response to the 10–12 May 2024 Canaan superstorm.Geophysical Research Letters (Open Access)
Astronomy, space weather