Recent observations have revealed that the thermosphere of the Earth has reached its peak temperature in the past 20 years, and what’s more surprising is that it is anticipated to continue heating up even after reaching this zenith. NASA has now shed light on the intriguing cause of this boiling-hot phenomenon occurring within one of the atmospheric layers.
Sitting as the second highest layer of the Earth’s atmosphere, the thermosphere, also known as the ionosphere, plays a crucial role as the Earth’s shield by absorbing a significant portion of the Sun’s ultraviolet radiation. Moreover, the ions generated within the thermosphere are essential for the utilization of radio signal reflection from one part of the globe to another.
Delving into the mechanics behind this scorching thermosphere, NASA elucidates that solar activity is at the core of this phenomenon. Solar storms generate geomagnetic storms, which are subsequently ejected towards the Earth, ultimately leading to the temperature surge observed in the thermosphere.
The thermosphere resides at an altitude of approximately 85 kilometers above the Earth’s surface, while beyond it lies the exosphere, extending up to 600 kilometers from the Earth. These atmospheric layers form a critical part of our planet’s intricate structure.
NASA has been actively involved in monitoring and measuring the thermosphere’s temperature for more than two decades. This has been accomplished through the utilization of infrared radiation emitted by specific molecules like carbon dioxide and nitric oxide.
By employing the Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED) satellite, data collected over this extensive period has been converted into the Thermosphere Climate Index (TCI). This index, measured in terawatts (TW), provides valuable insights into the thermosphere’s temperature dynamics.
The most recent TCI value surge occurred on March 10, peaking at an impressive 0.24 TW. Martin Mlynczak, a distinguished researcher from NASA’s Langley Research Center in Virginia and the creator of TCI, commented on this significant development, stating, “The last time TCI reached such a high level was on December 28, 2003.” These findings have been disseminated, but it’s important to note that they are still awaiting thorough peer review.
Multiple geomagnetic storms that took place during the months of January and February are responsible for triggering the remarkable temperature surge in the thermosphere. These storms, propelled by fast-moving coronal mass ejections (CMEs) and occasionally high-charged particle streams, induce substantial disturbances in the Earth’s magnetic field. This energy, in turn, gets deposited into the thermosphere, leading to its heating.
Mlynczak further explains, “The elevated heating results in higher levels of infrared emissions from nitric oxide and carbon dioxide in the thermosphere.” Interestingly, while infrared emissions typically cool down the thermosphere after a storm, the persistence of subsequent storms sustains the heightened temperature levels.
Since this initial temperature surge, the Earth has experienced at least two more geomagnetic storms. The first occurred on March 24, ranking as the most potent solar storm in over six years, and was followed by another equally powerful event on April 24. The TCI value has remained elevated following these storms, although it has not surpassed the peak recorded in March.
Geomagnetic storms, which become increasingly frequent and intense during the Solar Maximum phase, form a crucial part of the 11-year solar cycle when the Sun is at its most active state. This phase is characterized by the presence of dark sunspots and plasma loops ejecting CMEs and solar wind. Consequently, the Earth’s thermosphere aligns with this approximate 11-year cycle, showcasing its interplay with solar dynamics.
Leading scientists from NASA and the National Oceanic and Atmospheric Administration (NOAA) predict that the next Solar Maximum will transpire in 2025, indicating that the ongoing warming trend in the thermosphere is likely to persist for several more years. As we delve deeper into the intricacies of our planet’s atmosphere, these remarkable observations provide valuable insights into the interconnections between the Sun and Earth’s atmospheric layers.