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Ozone Hole 2005

Ozone Hole Area

Minimum Ozone

(million km2) (DU)
Maximum Daily Minimum Daily
Year Date Value Date Value
2005 11 September  27.3  30 September 103

http://ozonewatch.gsfc.nasa.gov

http://www.cpc.ncep.noaa.gov/products/stratosphere/sbuv2to/ozone_hole.sht

NASA Goddard Space Flight Center-On September 11, 2005, ozone thinning over Antarctica reached its maximum extent for the year at 27 millions of square kilometers. On October 1, 2005 the minimum ozone value was recorded at 102 Dobson Units.

 

 Situation at 2005 December 19 British Antarctic Survey Ozone BulletinStratospheric temperatures rose rapidly in November and the 2005 ozone hole is over. Generally ozone levels are at their summer maximum. There is, however, still a small area over the south pole with ozone levels below 250 DU, which is over 30% down on the normal for the time of year. The 2005 ozone hole was one of the deepest and largest recorded, with a peak of 25 million square kilometres in early September. Ozone values at Rothera in September were among the lowest recorded at this time of year, and values around 110 DU were reached on September 11, 19 and 20. Both Halley and Vernadsky recorded their second lowest values ever during September. The tip of South America and the Falkland Islands were affected by the edges of the ozone hole between August 30 and September 2; September 10 and 12; September 16 and 18; September 25 and 27. During these periods values dropped to over 20% below the normal for the time of year, and in the end of September event were over 30% down, with values below 200 DU. The region was affected by severe ozone depletion from October 7 to 10, when ozone amounts dropped 50% below the normal levels. South Georgia experienced low ozone values from October 9 to October 22. The Arctic ozone layer is in its winter state and temperatures near the top of the ozone layer are cold enough for stratospheric clouds to form. Ozone amounts over most of the Northern Hemisphere are generally between 250 and 400 DU. Stratospheric temperatures over the north Atlantic are below -75°C and ozone values over the northern UK are below 250 DU, which is approaching 30% below the normal for this time of year. Chemical ozone depletion is likely to be taking place. Elsewhere ozone values are generally not far from the normal.

Situation at 2005 October 28-The 2005 ozone hole was one of the deepest and largest recorded. The atmospheric circulation over the Antarctic continent is now emerging from its winter state. Stratospheric temperatures are however still cold enough for stratospheric clouds to exist, although temperatures are rising. Stratospheric clouds have been observed at Rothera and Vernadsky. There is still widespread ozone depletion over the continent, with ozone amounts over 50% down on the normal for the time of year in many places. Lowest ozone amounts are below 150 DU, though the ozone hole is beginning to fill. The lowest ozone areas are over the Elsworth Mountains. Overall the area of the ozone hole is around 13 million square kilometres. It is now significantly smaller than its peak of 25 million square kilometres in early September. Ozone values at Rothera in September were among the lowest recorded at this time of year, and values around 110 DU were reached on September 11, 19 and 20. The tip of South America and the Falkland Islands were affected by the edges of the ozone hole between August 30 and September 2; September 10 and 12; September 16 and 18; September 25 and 27. During these periods values dropped to over 20% below the normal for the time of year, and most recently have been over 30% down, with values below 200 DU. The region was affected by severe ozone depletion from October 7 to 10, when ozone amounts dropped 50% below the normal levels. South Georgia experienced low ozone values from October 9 to October 22. Temperatures in the Arctic stratosphere were cold enough for stratospheric clouds to form until mid March. Very low ozone levels (230 DU) were recorded over the UK from March 18 to 21. A rapid spring warming then took place and it is now too warm for such clouds to exist in the Arctic stratosphere. Ozone amounts over most of the Northern Hemisphere are generally between 220 and 350 DU. Parts of Siberia are 20% below the normal, but elsewhere they are generally 5 - 15% below the normal. Values over the UK are around 300 DU, which is a little above the normal for this time of year. Generally ozone amounts are declining towards the normal autumn minimum.

October  18 2005This year's seasonal ozone hole over Antarctica was the third largest on record, but forecasters are uncertain how it will behave in the future, the World Meteorological Organisation (WMO) said Tuesday.

October  13 2005 World Meteorological Organization- No 5/2005 Executive summary Since the last WMO Antarctic Ozone Bulletin 14 days ago, the area where temperatures are below the threshold for formation of PSCs of type I (nitric acid trihydrate, NAT) has continued to decrease and is now close to zero. This area has been close to the 2003 values and well above the 1995-2004 average throughout the month of September and the first week of October. The area where the total ozone column is less than 220 DU is now on the way down after reaching its maximum around 20 September. Although the ozone hole area has remained nearly constant during the last two weeks, it is now being filled up with ozone, and minimum values, as seen by satellites, are now around 125 DU, after being down to 106 DU on 30 September. Ground-based observations from Belgrano showed a total ozone column of 94 DU on 4 October, which is the lowest ever measured at that station. The maximum observed UV index at Antarctic stations has increased since the previous Bulletin from 4.4 to 6. At Ushuaia, Argentina, the UV index reached 8 on 8 October, which is unusually high for this time of the year.

Situation at 2005 October 6-British Antarctic Survey Ozone Bulletin 

The 2005 ozone hole is one of the deepest and largest recorded. The atmospheric circulation over the Antarctic continent is emerging from its winter state. Stratospheric temperatures have been cold enough for stratospheric clouds to form, and although temperatures are rising they are still widespread. Stratospheric clouds have been observed at Rothera and Vernadsky. There is widespread ozone depletion over the continent, with ozone amounts over 50% down on the normal for the time of year in many places. Lowest ozone amounts are below 100 DU, with all areas of the edge region below 200 DU, though amounts are beginning to rise. The lowest ozone areas are near Halley. Overall the area of the ozone hole is around 22 million square kilometres but is a little smaller in size than the 2003 hole, which was one of the largest on record. It is a little smaller than its peak of 25 million square kilometres in early September. Ozone values at Rothera in September were among the lowest recorded at this time of year, and values around 110 DU were reached on September 11, 19 and 20. The tip of South America and the Falkland Islands were affected by the edges of the ozone hole between August 30 and September 2; September 10 and 12; September 16 and 18; September 25 and 27. During these periods values dropped to over 20% below the normal for the time of year, and most recently have been over 30% down, with values below 200 DU. The region is likely to be affected by severe ozone depletion from October 8 to 10, when ozone amounts may drop 50% below the normal levels. South Georgia is likely to experience low ozone values until October 13.

Situation at 2005 September 23-British Antarctic Survey Ozone Bulletin 

The atmospheric circulation over the Antarctic continent is in its winter state. Stratospheric temperatures are cold enough for stratospheric clouds to form and they have been observed at Rothera and Vernadsky. There is widespread ozone depletion over the continent, with ozone amounts over 50% down on the normal for the time of year in places. Lowest ozone amounts are approaching 100 DU, with most areas of the edge region below 200 DU. The lowest ozone areas are over the base of the Antarctic Peninsula and the Weddell Sea. Overall the area of the ozone hole is around 22 million square kilometres but is a little smaller in size than the 2003 hole, which was one of the largest on record during August. Ozone values at Rothera are amongst the lowest recorded at this time of year. The tip of South America and the Falkland Islands was affected by the very edge of the ozone hole for a few days at the end of August and beginning of September, when values dropped to over 20% below the normal for the time of year.The tip of South America was again affected by the edge of the hole from September 10 to 13.  The area is likely to be affected again around September 22 - 25  

30 August 2005 European Space Agency-This season's Antarctic ozone hole has swollen to 

an area of ten million square kilometres from mid-August - approximately the same size as Europe 

and still expanding. It is expected to reach maximum extent during September, and ESA satellites 

are vital for monitoring its development. 

 

This year's hole is large for this time of year, based on results from the last decade: only the ozone 

holes of 1996 and 2000 had a larger area at this point in their development. Envisat's Scanning 

Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) routinely monitors 

ozone  levels on a global basis, continuing a dataset of measurements stretching back to mid-1995, previously made by the Global Ozone Monitoring Experiment (GOME) aboard the earlier ESA 

spacecraft ERS-2.

 

ESA data form the basis of an operational near-real time ozone monitoring and forecasting service forming part of the PROMOTE (PROtocol MOniToring for the GMES Service Element) consortium,

made up of more than 30 partners from 11 countries, including the Royal Dutch Meteorological Institute (KNMI).As part of the PROMOTE service, the satellite results are combined with meteorological data and wind field models so that robust ozone and ultraviolet forecasts can be made. In a first for ESA, these results are being used by the World Meteorological Organisation (WMO) to compile their regularly-updated Antarctic Ozone Bulletin.The precise time and range of Antarctic ozone hole occurrences are determined by regional meteorological variations. During the southern hemisphere winter, the atmospheric mass above the Antarctic continent is kept cut off from exchanges with mid-latitude air by prevailing winds known as the polar vortex. This leads to very low temperatures, and in the cold and continuous darkness of this season, polar stratospheric clouds are formed that contain chlorine.

The stratospheric ozone layer that protects life on Earth from harmful ultraviolet (UV) radiation is 

vulnerable to the presence of certain chemicals in the atmosphere such as chlorine, originating from man-made pollutants like chlorofluorocarbons (CFCs).

Now banned under the Montreal Protocol, CFCs were once widely used in aerosol cans and 

refrigerators. CFCs themselves are inert, but ultraviolet radiation high in the atmosphere breaks them down into their constituent parts, which can be highly reactive with ozone.

As the polar spring arrives, the combination of returning sunlight and the presence of polar stratospheric clouds leads to splitting of chlorine into highly ozone-reactive radicals that break ozone down into individual oxygen molecules. A single molecule of chlorine has the potential to break down thousands of molecules of ozone.


 The PROMOTE atmospheric ozone forecast seen here has atmospheric ozone measured in Dobson Units (DUs), which stands for the total thickness of ozone in a given vertical column if it were 

concentrated into a single slab at standard temperature and atmospheric pressure – 400 DUs is equivalent to a thickness of four millimetres, for example.

 

Developing out of the successful precursor Tropospheric Emission Monitoring Information Service (TEMIS), PROMOTE is a portfolio of information services covering the atmosphere part of the Earth System, operating as part of ESA's initial Services Element of Global Monitoring for Environment and Security (GMES). This is a joint initiative between ESA and the European Commission to combine all available ground- and space-based information sources and develop a global environmental monitoring capability for Europe.

August 22 2005 World Meteorological Organization-

From May to mid-August the meteorological conditions in the Antarctic stratosphere were close to the 1995-2004 average, colder than 2004, but a little warmer than in 2003.The total ozone column along the edge of the Antarctic air mass (vortex) is significantly smaller than at the same time in 2004 and also somewhat smaller than in 2003, when the largest ozone hole on record occurred. It is still too early in the season to give a reliable statement about the size and depth of this year's Antarctic ozone hole. WMO, in collaboration with the ozone science community, is using ozone observations and meteorological data to keep a close eye on the development during the coming weeks and months.

 

Most of Antarctica still remains under winter darkness, so the average rate of ozone loss there remains relatively low. However, total ozone column maps synthesised by the World Ozone and UV Data Centre at Environment Canada, using surface-based WMO/GAW network observations and satellite data, show that the sunlit parts of the vortex in mid-August have total ozone column values well below 200 DU and even close to 150 DU along the vortex edge, and in particular in the regions around the Antarctic Peninsula. 

This is considerably lower than at the same time in 2004 when the lowest ozone column was around 

240 DU and also somewhat lower than in mid-August 2003. This result has been confirmed by independent analyses and forecasts carried out by the Royal Netherlands Meteorological Institute

 

Temperatures are still sufficiently low within the polar vortex to maintain the chemical processes 

required for the formation of the annually recurring Antarctic ozone hole The ozone hole usually 

does not reach its maximum size until mid- to late September, but already by mid-August, one 

can see the first signs of ozone destruction. As the sun rises over Antarctica during the coming 

weeks, the ozone hole is expected to deepen. The amount of ozone loss will be dependent upon prevailing meteorological conditions in the stratosphere, particularly during September and October. This situation is expectedto continue as long as the stratosphere contains an excess of ozone depleting substances. In August, ozone loss is limited and the sun is still low in the sky, so the intensity of ultraviolet (UV) radiation in areas usually affected by the ozone hole is modest. UV levels will be reported in future ozone bulletins. 

 

Situation at 2005 June 20-British Antarctic Survey Ozone Bulletin

The atmospheric circulation over the Antarctic continent is in its early winter state.  The ozone layer over much of the Southern Hemisphere south of 50° is 10 - 15% below the long term normal.  Ozone values are below 230 DU over parts of Antarctica.  Stratospheric temperatures are now cold enough for stratospheric clouds to begin forming.

Information about the 2004 ozone hole is in the archive report for 2004/5.

Temperatures in the Arctic stratosphere were cold enough for stratospheric clouds to form until mid March.  A rapid spring warming then took place and it is now too warm for such clouds to exist in the Arctic stratosphere.  Ozone amounts over parts of the Northern Hemisphere  are over 15% below the normal, but all areas have ozone levels above 300 DU.  Although values over the UK are around 300 DU, this is 10% below the normal for this time of year, hence there is a high risk of sun-burn.  Values are expected to remain below normal for the next few days. Very low ozone levels (230 DU) were recorded over the UK from March 18 to 21.

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.  Prior to the formation of ozone holes, Antarctic ozone values were normally at their lowest in the autumn (ie March).

Halley - Total ozone:   The 2005 observing season will start in late August.  This figure [updated 2005 April 20] shows the variation in 2004 - 2005 and the normal for 1957-72.   

Rothera - Total ozone:   Mean values in 2005 fell slowly from 285 DU at the beginning of the year to 260 DU at the winter solstice, with long period  variation of around 20 DU from the mean, and shorter period variation of 30 DU.  This figure [updated 2005 June 28] shows the variation during the year.  

Vernadsky - Total ozone:  The 2005 observing season will start in July.  This figure [updated 2005 June 10] shows the variation in 2004 - 2005 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 at this height becomes sufficiently cold that polar stratospheric clouds (PSCs) can exist widely during the winter.   
Halley - 100 hPa temperature:   The temperature is at winter values of -80°C.  This figure [updated 2005 April 20] shows the variation at Halley in 2004 - 2005 and the normal for 1957-72.  
Peninsula - 100 hPa temperature:
   Since the beginning of January the 100 hPa temperature has been close to the long term normal.  This figure [updated 2005 June 10] (compiled from flights from Marambio, Rothera and the Polarstern) shows the variation in 2004 - 2005 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.  Strong winds on 2004 October 2 & 3 damaged the hangar at Rothera and this has significantly restricted the conditions under which sondes can be launched.  The Polarstern was stationed in the western Weddell Sea from early December 2004 to early January 2005 and launched one or two sondes each day.

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.  Our 2004/2005 Antarctic ozone hole movie [updated 2005 June 28] is produced from TOMS 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.

Arctic: Ozone values over the Arctic since June are shown in our Northern Hemisphere TOMS movie.  Ozone values declined from the spring maximum  in northern temperate and polar regions reaching the normal autumn minimum in early October.  The lowest ever UK reading from Lerwick was recorded on 2004 October 31.  Ozone values dropped below 200 DU over parts of the Arctic in early December.  Winter temperatures in the stratosphere were significantly colder than normal allowing extensive formation of stratospheric clouds.  This led to substantial ozone depletion, at times over 40%.  Very low ozone values, around 230 DU, were recorded over the UK between March 18 and 21.  Ozone values over the northern hemisphere are now at summer levels between 300 and  420 DU.  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 is broadly comparable to that seen in the Antarctic ozone hole.

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.