As Tonga deals with the consequences of the volcano’s eruption, this image illustrates how the cloud of sulfur dioxide is spreading across the planet
Using data from ESA’s Copernicus Sentinel-5P mission, the image shows the huge plume of sulfur dioxide on January 18 over Australia, more than 7000 km west of the eruption.
The Hunga-Tonga-Hunga-Ha’apai volcano near Tonga in the South Pacific erupted with such force on January 15 that it is believed to be the largest eruption recorded on the planet in 30 years.
Sending tsunami waves across the Pacific, the effects of this underwater eruption were felt as far away as the United States and Japan. Sonic booms from the eruption were heard across the Pacific and as far as Alaska, more than 9,000 km away, and the shock wave altered atmospheric pressure around the world.
The volcano spewed ash, gas and steam 30 kilometers into the atmosphere. Hazardous ash has smothered the island nation of Tonga, causing an unprecedented disaster.
Copernicus Sentinel-5P is dedicated to monitoring air pollution by measuring a multitude of trace gases and aerosols, all of which affect the air we breathe.
The gas that cools the planet
Apart from free oxygen, generated by the photosynthesis of plants, all atmospheric gases came from the interior of the earth and were released by volcanic eruptions. Of all of them, sulfur dioxide is responsible for acid rain, and when it escapes into the stratosphere, it generates a “parasol” that cools the planet.
The eruption of the Pinatubo volcano in the Philippines, which occurred on June 15, 1991, is estimated to have injected a cloud of sulfur dioxide of up to 20 million tons into the stratosphere.
The largest volcanic impact on the earth’s short-term weather patterns is caused by sulfur dioxide gas.
In the cold lower atmosphere, it is converted to sulfuric acid by the sun’s rays reacting with stratospheric water vapor to form sulfuric acid aerosol layers.
The aerosol remains in suspension long after the solid ash particles have fallen to the ground and forms a layer of sulfuric acid droplets between 15 and 25 kilometers high. Fine ash particles from an eruption column fall too quickly to significantly cool the atmosphere for an extended period of time, no matter how large the eruption is.
Sulfur aerosols last for many years and several historical eruptions show a good correlation of sulfur dioxide layers in the atmosphere with a decrease in the average temperature of subsequent years. The close correlation was first established after the eruption of the Agung volcano in Indonesia in 1963, when sulfur dioxide was found to reach the stratosphere and remain as an aerosol of sulfuric acid.
Without replenishment, the sulfuric acid aerosol layer around the earth gradually depletes, but is renewed with each sulfur dioxide-rich eruption. This was confirmed by data collected after the eruptions of El Chichon, Mexico (1982) and Pinatubo, Philippines (1991), both of which were carriers of high-sulfur compounds such as Agung, Indonesia.