The annual Antarctic ozone hole reached an average area of 8.9 million square miles (23.2 million square kilometers) between September 7 and October 13, 2022. This depleted area of the ozone layer above the South Pole was slightly smaller than last year and generally continued the overall downward trend of recent years. “Over time, there is constant progress and the hole is getting smaller,” said Paul Newman, chief scientist for Earth sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We do see some fluctuation as changes in weather and other factors cause the numbers to fluctuate slightly from day to day and week to week. But overall, we see it declining over the last two decades. Eliminating ozone-depleting substances through the Montreal Protocol is shrinking the hole.”
Ozone Depleting Reactions:
The ozone layer – the part of the stratosphere that protects our planet from the sun’s ultraviolet rays – thins every September, creating an “ozone hole” over the South Pole. Chemically active forms of chlorine and bromine in the atmosphere, derived from man-made compounds, join polar clouds at high altitudes every southern winter. Reactive chlorine and bromine then initiate ozone-depleting reactions as the sun rises at the end of the Antarctic winter.
NASA and NOAA researchers detect and measure the growth and decay of the ozone hole using instruments aboard the Aura, Suomi NPP, and NOAA-20 satellites. On October 5, 2022, these satellites observed a one-day ozone hole maximum of 10.2 million square miles (26.4 million square kilometers), slightly larger than last year.
As the auroral sun rises, NOAA scientists also take measurements with a Dobsonian 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 diameter is about 300 Dobsonian units. On October 3, 2022, scientists recorded the lowest value of total ozone in a column of 101 Dobson units over the South Pole. At that time, ozone was almost completely absent at altitudes between 8 and 13 miles (14 and 21 kilometers) — a pattern very similar to last year.
Some scientists have worried about the potential stratospheric impacts of the Hunga Tonga-Hunga Ha’apai volcano eruption in January 2022. The 1991 eruption of Mount Pinatubo released significant amounts of sulfur dioxide, which exacerbated ozone depletion. However, no direct impacts from Hunga Tonga were detected in the Antarctic stratospheric data.
Source : https://www.nasa.gov/esnt/2022/ozone-hole-continues-shrinking-in-2022-nasa-and-noaa-scientists-say
