New DelhiScientists have discovered that the local time a solar storm strikes the Earth is just as critical as the storm’s power in determining how much it scrambles our upper atmosphere.
They achieved this by analysing GPS signals, providing a better understanding of space weather over the Earth's magnetic equator.
During a solar storm, the Sun unleashes massive clouds of plasma known as coronal mass ejections.
These solar winds slam into Earth's magnetic shield, triggering geomagnetic storms that create energetic electrical currents in the sky.
When solar storms warp this atmospheric layer, signals can drop out entirely, leaving ships, aircraft, and digital infrastructure vulnerable.
New Delhi
Scientists have discovered that the local time a solar storm strikes the Earth is just as critical as the storm’s power in determining how much it scrambles our upper atmosphere. Researchers from CSIR-National Physical Laboratory, Academy of Scientific and Innovative Research (AcSIR), and SASTRA Deemed University tracked three intense geomagnetic storms between March 2023 and May 2024 at a station in Thanjavur, Tamil Nadu. They mapped the drastic changes in the ionosphere, part of Earth’s upper atmosphere, which stretches from about 60 km to 1,000 km and is composed of electrically charged particles.
They achieved this by analysing GPS signals, providing a better understanding of space weather over the Earth's magnetic equator. The ionosphere is heavily influenced by the Sun. During a solar storm, the Sun unleashes massive clouds of plasma known as coronal mass ejections. These solar winds slam into Earth's magnetic shield, triggering geomagnetic storms that create energetic electrical currents in the sky. During these events, two competing forces act in the ionosphere. The first is a rapid electric field that forces a fountain of charged particles upward, increasing the electron density high above the equator. However, a delayed secondary force driven by atmospheric heating acts like a global wind, pushing the particles back down into lower altitudes where they are destroyed, leading to massive, sudden drops in electron density.
The research team used ground-based GPS receivers to measure these opposing forces. As GPS satellites beam signals down to Earth, those signals must travel through the ionosphere. By calculating the slight delays in the signals caused by colliding with charged particles, the scientists could precisely measure the total electron content directly above the receivers. They compared the electron levels during the violent storms to the calmest days of the month, tracking extreme surges and sudden crashes in particle density.
The scientists noticed a pattern where a record-breaking storm in May 2024 that struck during the local midnight hours caused wild, rapid swings in particle density, whereas storms hitting closer to midday produced a much slower, prolonged swelling of the ionosphere. Their study shows that the physically most intense storm does not necessarily cause the greatest local atmospheric turbulence. An April 2023 storm actually triggered the largest percentage drop in electron density, plummeting by over 78% before suddenly surging back up, largely due to the specific evening hours during which its main phase developed.
This study provides one of the first direct, comparative ground-based analyses of multiple intense storms of completely different origins, specifically over the Indian near-equatorial sector. While earlier studies often examined single events or broad global patterns, this research highlights how local-time preconditioning dictates whether a storm will swell or shrink the atmospheric plasma. However, while the study offers regional insights, it is inherently limited by its reliance on a single observation station in Thanjavur to draw its regional conclusions. The researchers also acknowledge the extreme complexity of tracking these interacting atmospheric waves, making it a monumental scientific challenge to accurately predict their chaotic fluctuations across the entire globe.
The ionosphere is the invisible highway for the signals that power our GPS systems, aviation navigation, and long-distance communications. When solar storms warp this atmospheric layer, signals can drop out entirely, leaving ships, aircraft, and digital infrastructure vulnerable. By understanding precisely how the time of day and the nature of a solar storm alter the atmosphere, scientists can develop far more accurate space weather forecasting models, ultimately helping to protect the crucial satellite technology that our interconnected world relies upon every day.
