British Antarctic Survey Ozone

Halley, Rothera and Vernadsky/Faraday

This page gives information about ozone at Halley, Rothera and Vernadsky/Faraday stations and was last updated on 2004 June 22.


Situation at 2004 May 6

The final spring warming took place in early December and brought to an end the 2003 ozone hole.   Ozone values peaked in December and then slowly declined towards the normal autumn minimum.  They are now rising slightly in the normal winter circulation pattern.  Ozone values are generally slightly higher around Antarctica, with lower values over the continent.  They are generally close to  the long term normal.  

Ozone levels dropped quickly during August and September with the return of sunlight.  Depletion exceeded 60% in places, with some areas registering near 100 DU by the end of September.  The ozone hole grew rapidly and peaked in size at around 28 million square kilometres (roughly twice the size of Antarctica) in mid September. It was larger than previously for the time of year in August and early September, and the maximum size equalled the all time record.  Ozone levels  rose during October and briefly exceeded ozone hole limits in mid November.  Values dropped again giving an ozone hole area of a few million square kilometres in late November.  The final spring warming took place in early December, however this left many parts of Antarctica down 10 - 20% on the long term normal.  The tip of South America and the Falkland Islands suffered significant ozone depletion over October 4 - 9.  

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

Halley - Total ozone:   Note that routine ozone observations prior to late September are of low accuracy due to the low solar elevation.  Some measurements made using weak moonlight in early August show ozone values around 220 DU (25% depletion).   Routine solar observations show values declining from late August and by mid September they had dropped to around 130 DU (55% depletion).  They slowly declined to around 125 DU in early October (60% depletion).  Mean values rose rapidly to reach around 240 DU in late October (30% depletion).  Daily values dropped to 160 DU in mid November (mean values 210 DU, 40% depletion) and then rose to reach 300 DU in mid December (15% depletion). They are slowly falling and had reached around 240 DU (20% depletion) by the time the observing season ended in mid April.   This figure [updated 2004 May 6] shows the variation in 2003 - 2004 and the normal for 1957-72.   
Rothera - Total ozone:   In early June values began to fall, reaching around 250 DU by the end of July.  Values began to fall rapidly in August, reaching 110 DU by early October, with day to day variation around 30 DU.  Mean values rose rapidly in October to 310 DU, and remained near this level in early November, with a larger day to day variation around 50 DU and a peak of 350 DU.  In mid November mean values dropped again, reaching 230 DU in late November (daily minimum 169 DU on the 26th), returning to around 290 DU in December.  Values in 2004 fell slowly from 290 DU at the beginning of the year to 270 DU at the equinox and have now risen to around 280 DU.  This figure [updated 2003 May 12] shows the variation in 2002, when the ozone hole split into two, and this figure [updated 2004 May 6] the variation in 2004.  
Rothera - Ozonesondes:  In late September, ozonesonde flights from Rothera showed substantial depletion between 12 and 24 kilometres, with 100% depletion at times at some altitudes between 15 and 21 km.  A flight on October 22 still showed substantial depletion between 12 and 19 km, but ozone levels were much higher above 19.5 km (50hPa).  Our final ozonesonde flight (October 30) shows a peak ozone partial pressure of 23 mPa at 19 km, however there is still significant depletion between 11 and 16 km.  Animation of the ozonesonde flight results [note that although the ozone scale on these graphs reads nanobars, it should read mPa].
Vernadsky - Total ozone:  Observations show ozone values declining from around 270 DU (10% depletion) in late July to around 130 DU (60% depletion) at the end of September.  Values rose rapidly to 290 DU in the first half of October and then more slowly to peak at around 340 DU (5% depletion) in early November, but with large day to day variation.  They declined to around 250 DU (35% depletion) in late November (with a daily minimum of 211 DU on the 26th) before rising to around 300 DU (15% depletion) in early December. They then slowly fell, to reach around 270 DU (10% depletion) in early March before rising towards 290 DU by the end of April.   The daily mean of 160 DU on August 25 was the second lowest recorded for the month.  The monthly mean for September was the second lowest on record.  This figure [updated 2004 May 6] shows the variation in 2003 - 2004 and the normal for 1957-72. 

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 of the ozone layer above Antarctica rose rapidly in late November to summer values.  It is now cooling, but the temperature remains far too warm for PSCs to exist.   Halley reported sighting of PSC on July 28.  They photographed clouds which appear to have similarities to noctilucent clouds on August 8 (image1 / image2).  More clouds were photographed on September 16.  Vernadsky reported nacreous clouds on August 2, September 21, 23.  Rothera photographed some nacreous clouds on July 16.
Halley - 100 hPa temperature:  During October the 100 hPa temperature at Halley rose from winter values near -83°C to -64°C.  It paused for the first half of November, but then rose to reach -46°C in early December.  Values slowly increased to a peak of -43°C in mid December, some 2° below the normal.  By early January they had declined to -45°C, some 5° below the normal, but then rose to -42°C in mid month, a little below the normal of -40°C.  They slowly fell until mid March, when there was a more rapid decline to -55°C by the end of the month.  They are now around -58°C.  The 100 hPa temperature was generally been below the normal from August to February.  This figure [updated 2004 May 6] shows the variation at Halley in 2003 - 2004 and the normal for 1957-72.  
Peninsula - 100 hPa temperature:
  The 100 hPa temperature along the Antarctic Peninsula declined from -76°C at the beginning of August to -79°C at the beginning of October, with variation of a few degrees on a 20 day period.  During October it rose rapidly to reach near normal values around -51°C by the end of the month.  It remained near this value, but fell to -57°C in the last week of the month before rising to around near, though a little below, the normal at -44°C in mid December.  The temperature slowly fell to around -47°C early in January, but returned to near normal by mid month.  Since then it has slowly fallen, remaining a little below the normal.  This figure [updated 2004 May 6] (compiled from flights from Marambio and Rothera) shows the variation in 2003 - 2004 and the normal for 1957-72.  There has been a radiosonde programme of several flights per week at Rothera since 2003 March, increasing to daily flights for the QUOBI project from mid June to mid October 2003.  

Satellite: Satellite imagery gives a global perspective on the ozone hole. TOVS (which can image during the polar night) and TOMS currently have significantly different calibrations, with TOVS showing lower readings than TOMS.  TOMS values are close to ground-based values.  Different satellite operators use slightly different criteria for defining the area of the ozone hole and hence give slightly different areas.  Overall it is clear that this year we had one of the largest ozone holes on record.  The ozone hole or its edge crossed the tip of South America and the Falkland Islands on September 6/7, 20/21, 27-30 and October 4-9.  This region was also affected by areas of low ozone tropical air at the end of March and again around April 24 - 25, and May 4 -5.  Our 2003/2004 Antarctic ozone hole movie [updated 2004 May 6] is produced from TOMS images.  TOMS was out of action between November 27 and December 3.  The NCEP analyses shown on the Canadian Met Service daily ozone maps pages give a good analysis in the Southern Hemisphere but the forecasts tend to increase ozone amounts within the ozone hole. US NWS CPC plots from NOAA show the current area of the ozone hole.

Arctic: Ozone values over the Arctic during the course of a year are shown in our Northern Hemisphere TOMS movie for 2002/2003 (see also this year's movie).  Ozone values are declining from the spring maximum  in northern temperate and polar regions.  Ozone values over the UK are around the normal.  Temperatures are well above the PSC threshold throughout the arctic stratosphere.

Equator: Ozone levels are normally lowest over the topics and TOMS data shows nothing unusual. TOVS data has a calibration problem and shows values that are significantly lower than those that are measured by other means.


Background and related material

  • Royal Astronomical Society ozone fact sheet
  • The 2001 July edition of Weather included an article on the ozone hole entitled 'Back to basics:- The ozone hole'. This version is slightly revised and updated.
  • WMO Press Release on 2003 September 16 (Antarctic ozone hole unusually large)
  • BAS Press Release on 2003 September 12 (BA Festival of Science - The ozone hole)
  • Slides of talk 'The split Antarctic vortex - has it ever happened before ?' given at the RMS/ACSG meeting on 2003 August 29
  • Why does the ozone hole form over Antarctica?
  • Latest ozone bulletin 2002 May 28
  • Download a pdf version of the bulletin
  • BAS is involved in the QUOBI project to contrast the ozone layer over the Arctic with that of the Antarctic.  Trial ozonesonde flights took place at Rothera in 2003 March and regular flights began at the end of June.  Animation of the ozonesonde flight results.
  • Institute of Physics awards BAS Scientists the Charles Chree Medal and Prize
  • SCI Press Release BAS Scientists Awarded Environment Medal. This is what the medal looks like.
  • Severe Arctic ozone depletion in 2000
  • BAS was involved in a big international collaboration to measure the ozone hole in 1999 September and October. Details of ape-gaia are on the project web page.
  • BAS ozone pamphlet. A new (printed) edition was published in 1998 and is available from the BAS publicity section .
  • Statement on stratospheric Ozone and the Ozone Hole
  • The BAS press release of 1997 October 2 'Ozone hole starts to form in midwinter at sunlit edge of Antarctica'. A postscript image shows the calculated ozone depletion on 1994 July 23.
  • An ozone hole did not exist in 1956 (despite suggestions to the contrary) [updated 2002 October 14].
  • UK ozone information from the Met Office.
  • The ozone FAQ
  • Yahoo ozone discussion group
  • Some links to other sources of ozone information (updated 2003 August 13).
  • Canadian Met Service ozone information
  • Somewhat related is the subject of nacreous clouds , which were widely seen over the UK on 1996 February 18 and over Scotland on 1999 November 30. Very low ozone values were recorded over the North Sea on the later occasion, more details are available from NASA-TOMS . This event was probably caused by a combination of stratospheric and tropospheric dynamics (the stratosphere was very cold), with ozone depletion playing a minor role. On 2000 January 29 nacreous clouds were again seen over large parts of the UK. Stratospheric analyses show temperatures over the UK below -75 deg C on that day and the day before. Martin Brown has compiled a page of further information and pictures of the display. Significant ozone depletions of up to 30% were seen in some areas of the Arctic during early March.

  • Ozone bulletins

    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.


    Ozone data

    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 description. You must request permission to reproduce the data and I may be able to supply more suitable or more up to date material.

    Provisional daily mean ozone values for 2003/2004 for Halley  [Updated 2004 April 28] and Vernadsky.  [Updated 2004 June 15]  The data sets commence on August 1.  The instrument constants for Halley were adjusted on 2003 October 23 and those for Vernadsky on 2004 April 5.
    Provisional daily mean ozone values for Faraday/Vernadsky and Halley between 1972 and 2003.
    [Updated 2004 June 15]
    Provisional monthly mean ozone values for Faraday/Vernadsky and Halley between 1956 and 2004.
    Mean daily ozone values for the period 1957 - 1972 for Faraday and Halley .
    Daily ozone values for the period 1957 - 1973
    for Faraday and Halley .

    Temperature and Ozone graphs for Halley and Vernadsky/Faraday. [Updated 2004 June 15]

    Radiosondes are released daily at Halley. The 100 hPa or 70 hPa pressure level is close to the height of the maximum ozone concentration. Over the last 30 years the mean 100 hPa temperature has declined in most months. The most notable change is in November at Halley.
    Monthly 100 hPa temperature means for Bellingshausen/Faraday/Rothera/Marambio/Polarstern and Halley between 1954 and 2003. [Updated 2003 August 5]

    During 2003 we carried out ozone sonde flights at Rothera as part of the QUOBI projectData from these flights is available in NASA-AMES format.

    The SAOZ instrument at Rothera has measured total column nitrogen dioxide and ozone since 1997. The values given here are preliminary and only show general trends in ozone amounts.  In particular, the calibration of the instrument is such that it reads about 15% lower than a Dobson at values around 100 DU.
    Total column nitrogen dioxide 1997/1998.
    Total column nitrogen dioxide and ozone 1998, 1999, 2000, 2001, 2002, 2003 and 2004. [Updated 2004 May 6]  
    There is also a Bentham spectro-radiometer at Rothera. Provisional values for 1997 / 1998 / 1999 / 2000 / 2001 / 2003 / 2004 are available [Updated 2004 April 7]. The original instrument was destroyed in a fire on 2001 September 28, however a replacement was commissioned and became operational on 2003 March 3.

    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 and 2003/2004 [updated 2004 June 22].  A short sequence of the 2001 hole.
    Northern Hemisphere movies for 2000/2001 , 2001/2002 , 2002/2003 and 2003/2004 [updated 2004 June 22]  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 are compiled from daily TOMS images. They begin and end in June.
    Today's TOMS 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.


    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