When the Hunga Tonga-Hunga Há’apai volcano erupted on January 15, 2022, it sent atmospheric shock waves, sonic booms and waves of tsunami around the world. Now scientists are discovering that the effects of the volcano have also reached into space, as research reveals. published in the review Geophysical Research Letters.
When the volcano erupted, it pushed a giant cloud of gas, water vapor and dust into the sky. The explosion also created significant pressure disturbances in the atmosphere, resulting in high winds. As the winds expanded upward into thinner atmospheric layers, they began to move faster. When they reached the ionosphere and the outer reaches of space, ICON recorded wind speeds of up to 724 kilometers per hour, making them the strongest winds below 193 kilometers altitude, measured by the mission since launch.
In the ionosphere, extreme winds also affected electrical currents. Particles in the ionosphere regularly form an eastward-flowing electric current — called the equatorial electrojet — powered by winds from the lower atmosphere. After the eruption, the equatorial electrojet increased up to five times its normal peak power and changed direction dramatically, flowing west for a short time.
Effects on the ionosphere
“It’s very surprising to see the electrojet very inverted by something that happened on the Earth’s surface,” said Joanne Wu, a physicist at the University of California at Berkeley and co-author of the new study. . “This is something we’ve only seen before with strong geomagnetic storms, which are a form of weather in space caused by particles and radiation from the Sun.”
The new research contributes to scientists’ understanding of how the ionosphere is affected by events on Earth and in space. A strong equatorial electrojet is associated with the redistribution of material in the ionosphere, which can disrupt GPS and radio signals transmitted through the region.
Understanding how this complex area of our atmosphere responds to strong forces from above and below is a key part of NASA research. NASA’s upcoming Geospace Dynamics Constellation (GDC) mission will use a fleet of small satellites, along with ground-based weather sensors, to track electrical currents and atmospheric winds passing through the region. By better understanding what affects electrical currents in the ionosphere, scientists could be better equipped to predict serious problems caused by such disturbances.