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One of the most powerful volcanic eruptions on the planet shot such a huge amount of water vapor high into the atmosphere that it is likely to temporarily warm the Earth’s surface, according to observations from a NASA satellite.
When the Hunga Tonga-Hunga Ha’apai underwater volcano erupted on January 15, 40 miles (65 kilometers) north of Tonga’s capital, it created a tsunami as well as a sonic boom that swept the world — twice.
The eruption sent a tall column of water vapor into the stratosphere, which is between 8 and 33 miles (12 and 53 kilometers) above the Earth’s surface. That was enough water to fill 58,000 Olympic-sized swimming pools, according to NASA satellite measurements.
The discovery was made by the Microwave Limb Sounder instrument on NASA’s Aura satellite. The satellite measures water vapor, ozone and other atmospheric gases. After the eruption, scientists were surprised by the water vapor readings.
They estimate that the eruption delivered 146 teragrams of water into the stratosphere. One teragram is the equivalent of a trillion grams, and in this case it is equal to 10% of the water already present in the stratosphere.
This is almost four times the amount of water vapor that reached the stratosphere after the 1991 eruption of Mount Pinatubo in the Philippines.
A new study on the findings of water vapor published in July Geophysical Research Letters.
“We’ve never seen anything like this,” study author Luis Millan, an atmospheric scientist at NASA’s Jet Propulsion Laboratory in Southern California, said in a statement. “We had to carefully check all the measurements in the plume to make sure they were reliable.”
The Microwave Limb Sounder instrument can measure natural microwave signals from the Earth’s atmosphere and detect them even through thick ash clouds.
“MLS was the only instrument with a thick enough coating to capture the water vapor plume as it did, and the only one that was not affected by the ash ejected from the volcano,” Milan said.
The Aura satellite was launched in 2004 and since then has measured only two volcanic eruptions that have raised significant water vapor that high into the atmosphere. But the water money from the 2008 Kasatochi event in Alaska and the 2015 Calbuco eruption in Chile dissipated rather quickly.
Normally, powerful volcanic eruptions like Mount Pinatubo or the 1883 Krakatoa event in Indonesia cool the Earth’s surface temperature because the gas, dust, and ash they spew reflect sunlight into space. This “volcanic winter” occurred after the eruption of Mount Tambora in 1815, causing “the year without summerin 1816
The Tonga eruption was different because the water vapor it sent into the atmosphere could trap heat, which could cause higher surface temperatures. The excess water vapor can remain in the stratosphere for several years, according to the researchers.
The extra water vapor in the stratosphere can also lead to chemical reactions that temporarily contribute to the depletion of Earth’s protective ozone.
Fortunately, the warming effect of water vapor is expected to be small and temporary and will disappear as the additional vapor decreases. Researchers do not believe this will be enough to worsen existing conditions due to the climate crisis.
Researchers believe that the main reason for the amount of water vapor rising is due to the depth of the volcano’s caldera at 490 feet (150 meters) below the surface of the ocean.
If it was too deep, the depth of the ocean would muffle the eruption, and if it was too shallow, the amount of seawater heated by the erupting magma would not match what reached the stratosphere, the researchers said.
Scientists are still working to understand the unusually energetic eruption and all its superlatives, including hurricane-force winds reaching space.