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Antarctic Ozone Hole Continues to Shrink, Researchers Say

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The annual ozone hole over the South Pole reached an average area of 23.2 million km2 (8.9 million square miles) between September 7 and October 13, 2022, according to scientists from NASA and NOAA.

This map shows the size and shape of the ozone hole over the South Pole on October 5, 2022, when it reached its single-day maximum extent for the year. Image credit: Joshua Stevens / NASA’s Earth Observatory.

The ozone layer is a portion of Earth’s stratosphere that protects our planet from the Sun’s ultraviolet rays. It thins to form an ozone hole above the South Pole every September.

Chemically active chlorine and bromine in the atmosphere, derived from human-produced compounds, attach to high-altitude polar clouds each southern winter.

They then initiate ozone-destroying reactions as the Sun rises at the end of Antarctica’s winter.

Researchers measure the growth and breakup of the ozone hole with instruments aboard NASA’s Aura satellite, the NASA/NOAA Suomi NPP and NOAA-20 (previously known as JPSS-1 while in development) satellites.

On October 5, 2022, those satellites observed a single-day maximum ozone hole of 26.4 million km2 (10.2 million square miles).

When the polar Sun rises, NOAA scientists also make measurements with a Dobson spectrophotometer, an optical instrument that records the total amount of ozone between the surface and the edge of space — known as the total column ozone value. Globally, the total column average is about 300 Dobson Units.

On October 3, 2022, the researchers recorded a lowest total-column ozone value of 101 Dobson Units over the South Pole.

At that time, ozone was almost completely absent at altitudes between 14 and 21 km (8 and 13 miles) — a pattern very similar to last year.

Some scientists were concerned about potential stratospheric impacts from the January 2022 eruption of the Hunga Tonga-Hunga Ha’apai volcano.

The 1991 Mount Pinatubo eruption released substantial amounts of sulfur dioxide that amplified ozone layer depletion. However, no direct impacts from Hunga Tonga have been detected in the Antarctic stratospheric data.

“Over time, steady progress is being made, and the hole is getting smaller,” said Dr. Paul Newman, chief scientist for Earth sciences at NASA’s Goddard Space Flight Center.

“We see some wavering as weather changes and other factors make the numbers wiggle slightly from day to day and week to week.”

“But overall, we see it decreasing through the past two decades.”

“The elimination of ozone-depleting substances through the Montreal Protocol is shrinking the hole.”

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This article is based on text provided by the National Aeronautics and Space Administration.

Source : Breaking Science News

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