Earth’s thermosphere, the second-highest layer of the atmosphere, recently experienced a near 20-year temperature peak due to the energy absorbed from geomagnetic storms that occurred this year. This temperature increase is expected to continue in the coming years as solar activity intensifies, which could have implications for Earth-orbiting satellites, according to experts.
The thermosphere extends from around 53 miles (85 kilometers) above the ground to approximately 372 miles (600 km) above the ground, with outer space beginning beyond the exosphere, as stated by NASA. For over two decades, NASA has been measuring the temperature of the thermosphere using infrared radiation emitted by carbon dioxide and nitric oxide molecules. Data collected by NASA’s Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite is converted into the Thermosphere Climate Index (TCI), measured in terawatts (TW). The TCI value reached its peak on March 10, reaching 0.24 TW, the highest since December 2003. However, this data is yet to be peer-reviewed.
The temperature spike in the thermosphere was caused by three geomagnetic storms in January and February. Geomagnetic storms are major disturbances to Earth’s magnetic field triggered by coronal mass ejections (CMEs) and solar wind, which are ejected by the sun. These storms deposit energy in the thermosphere, resulting in increased heating and higher levels of infrared emission from nitric oxide and carbon dioxide. Normally, infrared emissions after a storm cool the thermosphere, but consecutive storms can maintain high temperatures.
Since the temperature spike, at least two more geomagnetic storms have occurred, with the TCI values remaining high but not surpassing the March peak. Geomagnetic storms become more frequent and intense during solar maximum, a phase in the roughly 11-year solar cycle when the sun is most active. As a result, Earth’s thermosphere also follows an 11-year cycle. Government scientists from NASA and NOAA predict that the next solar maximum will occur in 2025, indicating that the warming trend in the thermosphere will likely continue in the coming years.
The changes in the thermosphere pose challenges for satellites in low-Earth orbit positioned around its upper boundary. The thermosphere expands as it warms, resulting in increased aerodynamic drag on satellites and space debris. This increased drag can pull satellites closer to Earth, potentially causing collisions or complete orbital failure. Satellite operators can mitigate these issues by adjusting the spacecraft’s orbit, but the unpredictability of space weather makes it difficult to anticipate when such maneuvers are necessary.
There is also a possibility that solar maximum could arrive sooner than predicted. A recent study published in the journal Frontiers in Astronomy and Space Sciences suggests that the solar activity peak could occur as early as late 2023 and be more powerful than initially anticipated. If this scenario unfolds, the risk of satellite disasters would further increase.
However, over longer timescales, temperatures in the thermosphere are declining due to excess CO2 caused by climate change. This excess CO2 increases infrared emissions into space, as revealed by a study published in the journal Earth Atmospheric and Planetary Sciences on May 8.
The temperature fluctuations in the thermosphere highlight the complex interactions between Earth’s atmosphere and space weather. Monitoring and understanding these changes are crucial for the safe operation of satellites and the overall study of Earth’s climate system.
How does the increased temperature in the thermosphere due to geomagnetic storms affect Earth-orbiting satellites?
The thermosphere, which is the second-highest layer of Earth’s atmosphere, recently experienced a significant increase in temperature due to the energy absorbed from geomagnetic storms. Experts predict that this temperature rise will continue in the future as solar activity becomes more intense. This could pose challenges for Earth-orbiting satellites.
According to NASA, the thermosphere extends from approximately 53 miles to 372 miles above the ground, with outer space beginning beyond the exosphere. To measure the temperature of the thermosphere, NASA has been utilizing infrared radiation emitted by carbon dioxide and nitric oxide molecules for over two decades. Data collected by NASA’s TIMED satellite is converted into the Thermosphere Climate Index (TCI), which is measured in terawatts. On March 10, the TCI value reached its peak at 0.24 TW, the highest since December 2003. However, it is important to note that this data has yet to undergo peer review.
The temperature spike in the thermosphere was caused by three geomagnetic storms that occurred in January and February. Geomagnetic storms are major disruptions to Earth’s magnetic field that result from coronal mass ejections and solar wind ejected by the sun. These storms deposit energy in the thermosphere, leading to increased heating and higher levels of infrared emission from nitric oxide and carbon dioxide. Normally, the thermosphere cools down after a storm as a result of infrared emissions. However, consecutive storms can maintain high temperatures.
Since the temperature spike, there have been at least two more geomagnetic storms, resulting in the TCI values remaining high but not surpassing the March 10 peak.
This is a concerning development as the rising temperature in Earth’s thermosphere poses a significant threat to our satellites. It’s crucial that we prioritize finding sustainable solutions to mitigate this potential damage and safeguard our vital technological infrastructure.
This article sheds light on the concerning temperature peak in Earth’s thermosphere and its potential implications for satellites. It is imperative for scientists and space agencies to closely monitor these changes to ensure the safety and integrity of our vital communication and navigation systems in space.