2020 Arctic Ozone Hole is Largest Ever Observed
The largest recorded ozone layer hole over the Arctic has been detected by the OSIRIS instrument. Normally, holes of this magnitude form only over the South Pole, as the conditions required to form an ozone hole over the North Pole are rare. The last hole to form over the North Pole was in 2011.
A stable polar vortex formed this year over the North Pole, which allowed the ozone-depleting CFCs to reduce the region's ozone layer without being dissipated by the surrounding atmosphere.
Figure 1 shows ten days of OSIRIS measurements over mid-March at various altitudes. The hole is apparent, especially when compared to all of the March 2018 measurements shown in Figure 2, which represent typical values.
Figure 3 shows OSIRIS ozone profiles from different areas around the Pole, some profiles inside the ozone hole region and others outside for comparison.
Unprecedented Forest Fire Aerosol in the Stratosphere
In this study we use satellite measurements, including OSIRIS, that observe the vertical structure of the atmosphere with high sensitivity to thin aerosol layers to report on the long‐lasting stratospheric effect of western North American wildfires from the summer of 2017. Aerosol from these fires was known to reach the stratosphere and circulate throughout the Northern Hemisphere. However, these satellite measurements, which have a record that stretches almost 40 years, show that this fire generated a stratospheric aerosol cloud almost 10 times thicker than background levels and lasted for more than 5 months. This is the largest impact from wildfires ever observed in the 40‐year satellite record.
OSIRIS Ozone Contributes to 2018 Scientific Assessment of Ozone Depletion
OSIRIS stratospheric ozone profile measurements from 2002-2018 were used to assess the trends in ozone recovery reported in the 2018 Ozone Assessment. These data helped to conclude that the start of the recovery of stratospheric ozone has begun, and that the continued success of the Montreal Protocol in protecting stratospheric ozone depends on continued compliance.