The Hunga Tonga-Hunga Ha’apai volcanic eruption, which occurred on January 15, 2022, was the largest volcanic eruption of the 21st century. This eruption ejected a water plume that reached the boundary where Earth’s atmospheric weather and space weather meet (ionosphere), creating atmospheric waves along Earth’s magnetic field lines and a sonic boom that circled the globe twice. Based on data from the Aura Microwave Limb Sounder (MLS) instrument, Luis Millán and colleagues determined that this eruption ejected enough water vapor into the stratosphere to fill 58,000 Olympic-size swimming pools, creating a temporary warming effect from heat trapped in the water vapor. The water vapor crystalized into grains of ice that collided with one another, creating electrical charges that triggered the most extreme lightning event ever detected (400,000 lightning strikes on January 15). NASA’s and ESA’s satellites in the area at the time detected these impacts, providing the first direct evidence of immediate electrodynamic effects from a volcanic explosion in the ionosphere. Consequently, this eruption offers unique insight into Earth’s environmental systems.

Based on data from NASA’s Global Ultraviolet Imager (GUVI) and the Air Force Defense Meteorological Satellite Program (DMSP) Special Sensor Ultraviolet Spectrographic Imager sensors, Larry Paxton and colleagues from Johns Hopkins University showed that the volcanic plume reached higher than 150 kilometers. The imagers flew over the eruption, reporting > 70% reductions in the detection of the major elements (e.g., O, N, and H) over ~1000-kilometer stretches in the Earth’s thermosphere, which is the layer of the atmosphere above the mesosphere and below the height where the atmosphere ends, from ~ 90 kilometers to ~500 -1,000 kilometers above Earth. The DMSP data allowed the decay time of the injected volcanic material (~6 hours) and the time for recovery of the upper atmosphere (~24 hours) to be estimated. Based on these observations, Paxton and the team proposed a link between volcanic processes and the evolution of the upper atmosphere of proto-Earths. READ MORE