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ANTARCTIC OZONE

This page gives information about ozone at Halley, Rothera and Vernadsky/Faraday stations. It was either updated or new data was added on 2007 June 14.

Situation at 2007 June 4

Ozone levels across Antarctica dropped rapidly in September and were generally at their minimum in early October.  The ozone hole grew rapidly from mid August and reached nearly 28 million square kilometres in size at the equinox.  The ozone hole was at record or near record size from mid September until late November, when it began to decline rapidly.   The ozone hole persisted until early December.   Although not an absolute record in size it was a record for the amount of ozone destroyed.  Halley recorded 99 DU on October 7, amongst the lowest daily values recorded at the station.  When the ozone hole became more elliptical the edge of the ozone hole passed over the tip of South America and South Georgia, and over the latter uv levels reached similar values to those seen at mid-day in the tropics.  

The winter polar vortex is beginning to build, and higher ozone values are seen outside the vortex.  The temperature of the ozone layer is declining from the summer high and temperatures in the ozone layer are now close to the mean of the last few decades, having generally been below the mean from March 2006 until March 2007.  A significant part of the Antarctic stratosphere is now below the temperature  at which stratospheric clouds can form.  

A prediction made at the SCAR conference in Hobart in July suggested that the 2006 ozone hole was likely to be one of the larger and deeper ones (perhaps 28 million square kilometres), based on a correlation with the 100 hPa temperature.  [This prediction was clearly confirmed.]  Adrian Tuck predicted a significant spring warming before mid October [no significant warming occurred].  In early June 2007 the minimum temperature of the Antarctic stratosphere was close to the normal, suggesting the likelihood of an average ozone hole year.

Note:  The Antarctic ozone hole is usually largest in early September and deepest in late September to early October.  September 16 is world ozone day.  2007 is the International Year of the Ozone Layer.  Prior to the formation of ozone holes, Antarctic ozone values were normally at their lowest in the autumn (ie March).  

Halley - Total ozone:   A few moon observations carried out on August 8 suggested that ozone values were not far from normal at around 300 DU.  Mean values then dropped fairly steadily, reaching around 110 DU in early October (65% down on the normal for the time of year).  This corresponds to a decline of roughly 1% per day since early August.  Provisionally, the minimum daily value recorded was 99 DU on October 7, the lowest ever recorded at the station.  Values rose to just above 180 DU (50% down on the normal for the time of year), but remained roughly constant until late November, when a spring warming began.  There was something of a standstill in early December, but after mid month values rose again to reach around 300 DU (15% depletion) at the solstice.  Values declined and were around 250 DU (15% depletion) by early April.  Note that the instrument constants were revised on 2007 February 5 and previously published values have changed significantly.  Further revisions will occur, but future changes should be smaller.  The ozone observing season has now finished.

Rothera - Total ozone:   Ozone values for the first two months of 2006 were around 270 DU, but slowly increased to around 300 DU at the winter solstice.  Mean values fell after the solstice and reached a minimum of around 120 DU in early October.  The minimum daily value was 105 DU on September 18.  A significant rise in ozone amount to 280 DU occurred in early October, but values then fell to 220 DU at the end of the month.  They slowly increased and had risen to around 300 DU by the end of the year.  By early January they had commenced the decline to the autumn minimum and were around 250 DU in mid March.  Daily values rose above 300 DU at the beginning of April, but have generally been around 270 DU, with variation due to planetary wave activity.

Vernadsky - Total ozone:   Vernadsky station is run by the National Antarctic Scientific Centre of Ukraine.  The early observations made in late July showed significant ozone depletion.  Vernadsky was often near the edge of the polar vortex, and consequently saw large day to day changes in ozone amount.  Depletion averaged around 40%.  The lowest daily value  recorded was 131 DU on September 18.  Ozone values rose to around 290 DU in mid October and remained near this level, though with considerable day to day variation.   Values were around 310 DU (15% depletion) at the summer solstice.  During the first half of 2007 they have been around 270 DU (10% depletion), though with variation over timescales of up to a month.  

Temperature and PSCs:   The 100 hPa pressure level is near the base of the ozone layer, but is reached by most radiosonde flights.    The temperature at this height is sufficiently cold from July to October that polar stratospheric clouds (PSCs) can form.   The temperature is currently above the PSC threshold across Antarctica but is cooling towards winter.  PSCs were reported from Rothera during spring 2006.
Halley - 100 hPa temperature:     The 2006 Antarctic spring was exceptionally cold at this level.  September was the 2nd coldest, October the 3rd coldest and November the coldest on record.  The value of -69.1°C recorded on December 1st is the second lowest recorded for the month, with 1996, which had a very late warming, setting the record.  The temperature at the 100 hPa level slowly warmed from the mid September minimum of  -85°C, reaching -70°C in early December some 25 degrees below the normal.  A more rapid warming then commenced, albeit with an interruption around December 11 and reached -43°C at the solstice , still 3 degrees below the normal.  The temperature remained near this value, with a drop in mid January, until mid February, when the decline to winter values began, with the temperature a little below the long term normal.  The temperature had dropped to around -60°C by early May, which is close to the long term normal.  
Peninsula - 100 hPa temperature:     The temperature at the 100 hPa level was below or close to the normal during August and September.  It generally declined during September and was substantially below the normal by early October.  It rose to near normal levels in mid October but was again substantially below the normal from mid November to mid December.  The temperature peaked near the normal at around the time of the solstice and began to decline.  There was a drop to significantly below normal values in late January and another in early March. 

Satellite: Satellite imagery gives a global perspective on the ozone hole.  Our 2006/2007 Antarctic ozone hole movie [updated 2007 February 28] is produced from OMI images.   The NCEP and KNMI analyses shown on the Canadian Met Service daily ozone maps pages give a good analysis in the Southern Hemisphere but the NCEP forecasts tend to increase ozone amounts within the ozone hole. US NWS CPC plots from NOAA show the current area of the ozone hole.  The ozone hole passed over the tip of South America and the Falkland Islands around October 4, October 7 to 10 and over South Georgia between September 18 to 24, October 9 to 12 and 22 to 25, November 16.  The Sciamachy uv index from the ESA  Tropospheric Emission Monitoring Internet Service shows the exposure risk at any location.

Arctic:  The spring warming is now over and maximum ozone values are subsiding.  The 2007 spring was sufficiently cold for stratospheric clouds to form and thus for chemical ozone depletion to take place, particularly over the general area of the European arctic.  Ozone values never dropped to ozone hole levels, however there was substantial depletion at times.  Ozone values over the Arctic since June are shown in our Northern Hemisphere TOMS movie.   For more UK information see the DEFRA UK Stratospheric Ozone Measurements page.    

Reports of a substantial Arctic ozone hole forming in response to a solar proton event in the spring of 2004 are somewhat exaggerated.  Although this did lead to substantial depletion of up to 60% near the top of the ozone layer, less than 10% of the total ozone column is in this region.  The event therefore had less effect than normal day to day changes and no ozone hole was formed.  The spring of 2005 by contrast had much lower stratospheric temperatures and significant chemical ozone depletion did take place.  Although the column ozone never quite dropped to "ozone hole" levels, the amount of ozone affected by chemical depletion was broadly comparable to that seen in the Antarctic ozone hole.

Equator: Ozone levels are normally lowest over the topics and OMI data shows nothing unusual.

The BAS ozone bulletins contained the actual ozone values reported together with an analysis of the situation. These were distributed by email on request, but are now superceded by this web site.  The last ozone bulletin was issued on 2002 May 28.  The final situation report of each season is archived for historical reference.

Some data is available on line, however please note that this is provisional and likely to change without warning. To help interpret the data you should to read this metadata description [updated 2007 June 14]. You must request permission to reproduce the data and I may be able to supply more suitable or more up to date material.  If data from Halley is used you must give the station name as Halley;  Halley Bay was a geographical feature that no longer exists.

Provisional daily mean ozone values for 2006/2007 for Halley  [Updated 2007 May 3] and Vernadsky.  [Updated 2007 May 24]  
Provisional daily mean ozone values for Faraday/Vernadsky and Halley between 1972 and 2007. [Updated 2007 May 25]
Provisional monthly mean ozone values for Faraday/Vernadsky and Halley between 1956 and 2007.
Mean daily ozone values for the period 1957 - 1972 for Faraday and Halley. [NB: not corrected to Bass-Pauer]
Daily ozone values for the period 1957 - 1973 for Faraday and Halley.  [NB: not corrected to Bass-Pauer]

Temperature and Ozone graphs for Halley and Vernadsky/Faraday. [Updated 2006 August 31].  The historic period shown in the inline graphs is for 1957 - 1972.

Stratospheric Temperature
Monthly 100 hPa temperature means for The Antarctic Peninsula and Halley between 1954 and 2005. [Updated 2006 August 31]

Rothera - Ozonesondes:  During 2003 we carried out ozone sonde flights at Rothera as part of the QUOBI project.  Data from these flights is available in NASA-AMES format.  Animation of the ozonesonde flight results [note that although the ozone scale on these graphs reads nanobars, it should read mPa].

Rothera - Ozone & nitrogen dioxide:  
SAOZ total column nitrogen dioxide and ozone 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 and 2007 [Updated 2007 June 4].  
Bentham ozone. Provisional values for 1997 / 1998 / 1999 / 2000 / 2001 / 2003 / 2004 [updated 2004 November 5 ]. 

Some background information on Halley, Rothera and Faraday stations is available from BAS. Information about Vernadsky station is also available from the Ukrainian Antarctic Centre. Information about Vladimir Ivanovich Vernadsky

Some surface and upper air synoptic data is also available on line from our public data page.

Southern Hemisphere ozone hole movies for 1997/1998 , 1998/1999 , 1999/2000 , 2000/2001 , 2001/2002 , 2002/2003 , 2003/2004 , 2004/2005 , 2005 [TOMS], 2005/2006 and 2006/2007 [OMI, updated 2007 May 3].  A short sequence of the 2001 ozone hole.
Northern Hemisphere movies for 2000/2001 , 2001/2002 , 2002/2003 , 2003/2004 , 2004/2005 , 2005 [TOMS], 2005/2006 and 2006/2007 [OMI updated 2007 May 3]  A short sequence of ozone depletion during the 2002/03 northern winter showing the difference from the normal.
These annual movies are each about 8Mb and were compiled from daily TOMS images until the end of 2005; from 2005/06 they are compiled from OMI images. The movies begin and end in June.
Today's OMI global image
The current area of the hole and other latest details are available from the NOAA Climate Prediction Center.
Environment Canada have an excellent set of daily maps showing both northern and southern ozone levels from a variety of sources.
The Sciamachy uv index from the ESA  Tropospheric Emission Monitoring Internet Service.  Note that west longitude is negative when entering co-ordinates.

Contacts

Requests for permission to use this data or for further information should be sent to Jon Shanklin who maintains these pages.

NERC / BAS / MET