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The Ozone Hole 2018
 

Antarctic Situation at 2018 September 14British Antarctic Survey Ozone Bulletin

Antarctic ozone today:  Ozone values are dropping across the continent and the 2018 ozone hole has formed.  The hole is currently of average size for the decade at 20 million square kilometres.  The lowest ozone values, about 170 DU, are near McMurdo.  Amounts are higher, over 400 DU in places over the southern ocean, particularly south of Australia and New Zealand.  Ozone depletion is increasing, with values widely below the ozone hole threshold of 220 DU.  Ozone values over the continent range from around 170 DU to 260 DU.  There are marked differences between the various satellite ozone measurements and analyses across the Southern Hemisphere.  The KNMI analysis and TEMIS forecasts are close to the observed values, whereas the Canadian analysis seems largely based on SMOBA data and is clearly at variance with ground based observations.   The southern polar vortex is near its maximum size.  The atmospheric circulation is still in winter mode.   Temperatures in the ozone layer are just past their minimum and with the temperature widely below  -78°C Polar Stratospheric Clouds (PSC) are extensive in the central part of the ozone layer over the continent.  Ozone values are continuing to drop across the continent.  Temperatures are highest in a broad ring around 45°S and decline towards the pole, where they are coldest, and to the equator .  They are generally a little below the normal within the polar vortex.  The vortex area is a little larger than the decadal mean at around 34 million square kilometres near the centre of the ozone layer.  The area with PSCs present has passed its largest of around 27 million square kilometres, and has shrunk to around 20 million square kilometres, close to the decadal mean.  In general the lower stratosphere is of above average stability for the time of year and hence the vortex is roughly circular in shape.

The 2018 ozone hole:  The polar vortex began to form in early May and reached its maximum area in mid September at around 34 million square kilometres.  It was a little larger than the decadal mean in size, and was generally of average or above average stability.  PSCs began to form in mid May and the maximum area with potential PSCs was larger than the decadal mean and close to the maximum of the last decade at around 27 million square kilometres.  Ozone hole values below 220 DU were reached in late August, later than in the past couple of years; this was largely due to the stability in the stratosphere this year.  The ozone hole grew rapidly and by mid September was of average size for the decade at 20 million square kilometres.  Ozone values continue to drop across the continent.  Ozone depletion is expected to intensify over the coming week.

 

 
The graphs above show the progress of the ozone hole for 2018. The gray shading indicates the highest and lowest values measured since 1979. The red numbers are the maximum or minimum values. The stratospheric temperature and the amount of sunlight reaching the south polar region control the depth and size of the Antarctic ozone hole. The dashed line in the minimum temperature plot indicates the temperature below which Type I (NAT) PSCs can form.   https://ozonewatch.gsfc.nasa.gov

Antarctic Situation at 2018 September 3British Antarctic Survey Ozone Bulletin

Antarctic ozone today:  Ozone values are dropping across the continent and the 2018 ozone hole has formed.  The southern polar vortex is near its maximum size.  The atmospheric circulation is in winter mode with generally lower ozone over the continent and higher ozone over the Southern Ocean.   The lowest ozone values, below 200 DU, are near Halley.  Amounts are higher, over 400 DU in places over the southern ocean, particularly south of Australia.  Ozone depletion is increasing, with values below the ozone hole threshold of 220 DU.  Ozone values over the continent range from around 190 DU to 270 DU.  There are marked differences between the various satellite ozone measurements and analyses across the Southern Hemisphere.  The KNMI analysis is close to the observed values, whereas the Canadian analysis seems largely based on SMOBA data and is clearly at variance with ground based observations.   Temperatures in the ozone layer are nearing their minimum and with the temperature widely below  -78°C Polar Stratospheric Clouds (PSC) are extensive in the central part of the ozone layer over the continent.  Ozone values are continuing to drop over sunlit parts of the continent.  Temperatures are highest in a broad ring around 45°S and decline towards the pole, where they are coldest, and to the equator .  They are generally a little below the normal within the polar vortex.  The vortex area is close to the decadal mean at around 32 million square kilometres near the centre of the ozone layer.  The area with PSCs present is past its largest of around 27 million square kilometres, and has shrunk to around 24 million square kilometres, still a little larger than the decadal mean.  In general the lower stratosphere is a little above average stability for the time of year and hence the vortex is roughly circular in shape.

The 2018 ozone hole:  The polar vortex began to form in early May and reached its maximum area in mid August at around 32 million square kilometres.  It was a little larger than the decadal mean in size, and was generally of average or above average stability.  PSCs began to form in mid May and the maximum area with potential PSCs was larger than the decadal mean and close to the maximum of the last decade at around 27 million square kilometres.  Ozone hole values below 220 DU were reached in late August.  Ozone values are dropping over sunlit parts of the continent.  Ozone depletion is expected to intensify over the coming week.



Antarctic Situation at 2018 August 24British Antarctic Survey Ozone Bulletin

Antarctic ozone today:  Ozone values are dropping across the continent.  The southern polar vortex continues to grow, but is nearing its maximum size.  The atmospheric circulation is in winter mode with generally lower ozone over the continent and higher ozone over the Southern Ocean.   The lowest values, just below 220 DU, are on the northern fringes of the continent, but amounts are higher, near 450 DU in places, and building, over the southern ocean, particularly south of Australia and India.  Ozone depletion is increasing, with values at the ozone hole threshold of 220 DU.  Most short-term variation in ozone amount is due to dynamic processes.  Ozone values over the continent range from around 220 DU to 290 DU.  There are marked differences between the various satellite ozone measurements and analyses across the Southern Hemisphere.   Temperatures in the ozone layer are nearing their minimum and with the temperature widely below  -78°C Polar Stratospheric Clouds (PSC) have formed in the central part of the ozone layer over the continent.  Ozone values are dropping over sunlit parts of the continent, but have not quite reached ozone hole levels on a continuous basis.  Temperatures are highest in a broad ring around 45°S and decline towards the pole, where they are coldest, and to the equator .  They are generally a little below the normal within the polar vortex.  The vortex is growing in area, and is a little larger in size than the decadal mean at around 32 million square kilometres near the centre of the ozone layer.  The area with PSCs present is near its largest and is larger than the decadal mean and close to the maximum for the decade at around 27 million square kilometres.  In general the lower stratosphere is a little above average stability for the time of year and hence the vortex is roughly circular in shape.

The 2018 ozone hole:  The polar vortex is nearing its maximum area.  It is a little larger than the decadal mean in size, and generally of average stability.  The area with potential PSCs is larger than the decadal mean and close to the maximum of the last decade.  Ozone values are dropping over sunlit parts of the continent, and are near ozone hole levels.  Ozone depletion is expected to intensify over the coming week.

Provisional indications suggest that ozone hole levels were reached in the Arctic on 2018 February 3.  The region affected was between Svalbard and Scandinavia.  Very low ozone occurred over the west coast of Canada on February 12, 13, 16 and 17 in an event that was probably dynamically forced, although PSCs were seen.  A spring warming has occurred and all parts of the Arctic ozone layer are now above the PSC formation threshold.