Historical data relating to the ozone layer

compiled by Wm. Robert Johnston
last updated 18 May 2006

See notes


------------------- | year  |  global | (65S-65N) |   (DU) ------------------- |    O1 -------------------

1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958      298.8 S    330.6 1959      297.0 S    336.0 1960      297.0 S    339.6 1961      289.9 S    316.1 1962      294.9 S    329.9 1963      294.9 S    328.9 1964      294.9 S    321.6 1965      297.3 S    327.4 1966      296.7 S 1967      296.4 S    322.8 1968      301.2 S    333.2 1969      298.2 S    331.2 1970      301.7 S    339.5 1971      298.8 S    330.3 1972      298.2 S    333.9 1973      296.1 S    332.1 1974      296.1 S    325.5 1975      296.4 S    319.8 1976      297.0 S    329.5 1977      297.9 S    333.0 1978      297.0 S    324.3 1979      299.7 1980      297.3 1981      297.7 1982      297.4 1983      292.4 1984      293.6 1985      288.6 1986      290.6 1987      291.1 1988      291.3 1989      295.2 1990      291.3 1991      293.2 1992      287.4 1993      280.6 P    299.1 1994      287.8 P    315.1 1995      282.2 P    304.9 1996      288.5 P    314.8 1997      286.1 1998      290.0 1999      288.0 2000      287.1 2001      288.2 2002      285.8 2003      285.0 2004      281.2 2005      283.5 2006

------------------- |    O1 ------------------- | year  |  global | (65S-65N) |   (DU) -------------------

after table for explanations and sources. -------------------------------------------------------------------------------- column total ozone, annual average | sunspot | anthrop. | anthropogenic Arosa N. hemis. equator S. pole | number | chlorine | chlorine in (47N) (25N-50N) (10S-10N) (90S) | | emissions | atmosphere (DU) (DU) (DU) (DU) | | (Mg/yr) | (Mg) -------------------------------------------------------------------------------- O2 O3 O4 O5 | S1 | CL1 | CL2 -------------------------------------------------------------------------------- 37.6 26.1 14.2 5.8 16.7 44.3 289.0 P 63.9 330.8 69.0 313.6 77.8 371.1 P 64.9 295.8 P 35.7 301.1 P 21.2 323.5 11.1 0 0 E 344.3 5.7 59 60 E 324.7 8.7 120 180 E 332.5 36.1 182 350 E 333.3 79.7 320 650 E 336.4 114.4 496 1110 E 323.6 109.6 685 1730 E 319.6 88.8 1050 2680 E 360.2 67.8 1361 3880 E 349.0 47.5 1849 5500 E 336.1 30.6 2223 7400 E 328.1 16.3 2784 9800 E 321.3 9.6 3756 12900 E 333.5 33.2 4849 17000 E 322.7 92.6 8648 24700 E 336.2 151.6 13472 36700 E 327.6 136.3 16331 50900 E 326.9 134.7 18587 66000 E 332.3 83.9 21612 84000 E 335.8 P 69.4 25097 104000 E 345.5 31.5 28618 127000 E 336.0 P 13.9 34558 154000 E 333.0 P 4.4 41102 186000 E 331.4 38.0 49689 225000 E 330.4 141.7 61479 273000 E 318.3 190.2 71456 328000 E 184.8 73160 380000 E 159.0 82229 437000 E 112.3 101458 509000 E 53.9 118598 593000 E 37.6 145164 700000 E 27.9 171887 820000 E 300.9 P 10.2 201633 960000 E 287.3 P 15.1 234310 1130000 E 332.5 P 301.6 P 47.0 275850 1330000 E 319.0 P 93.7 324994 1550000 E 323.6 P 105.9 375012 1810000 E 292.7 P 105.5 430638 2100000 E 303.0 P 104.5 471417 2410000 E 297.2 P 66.6 526453 2770000 E 356.0 P 68.9 603849 3180000 E 292.8 P 38.0 700274 3650000 E 283.9 P 34.5 777692 4160000 E 289.0 P 15.5 767178 4610000 E 292.6 P 12.6 828579 5090000 E 290.7 P 27.5 879843 5440000 E 291.9 P 259.6 P 292.4 P 92.5 894847 5960000 E 332.3 322.2 260.4 296.9 P 155.4 881478 6439400 324.4 319.9 267.0 287.7 P 154.6 900129 6758200 327.9 320.7 261.5 284.1 P 140.5 919000 7106300 327.9 323.6 263.2 272.3 P 115.9 900828 7434000 312.1 311.7 258.3 310.0 P 66.6 936275 7812200 327.4 316.7 255.9 256.9 P 45.9 1008649 8079300 313.7 307.1 266.2 244.5 P 17.9 1033721 8511300 322.3 313.1 256.6 243.3 P 13.4 1065012 8942800 324.1 316.2 259.5 241.8 P 29.2 1101675 9451100 326.5 P 308.0 260.7 263.2 P 100.2 1142927 9906300 317.1 313.7 262.8 249.2 P 157.6 1118191 10243700 315.2 309.6 270.3 230.5 P 142.6 1076222 10562900 325.9 316.8 259.2 250.6 P 145.7 974587 10817700 304.7 306.4 260.4 250.4 P 94.3 921088 11094600 293.6 P 256.3 P 246.4 P 54.6 730082 10975100 304.9 P 256.2 P 242.1 P 29.9 578771 10734400 287.1 P 257.6 P 234.7 P 17.5 520118 10511000 280.9 P 257.1 P 226.3 P 8.6 397255 10282000 306.3 302.5 260.0 247.0 P 21.5 330317 10022300 323.2 310.3 257.3 233.8 P 64.3 296784 9796800 318.7 302.7 266.0 230.8 P 93.3 278881 9592800 308.3 304.3 257.7 250.2 P 119.6 261953 9453500 319.1 305.9 255.7 215.0 P 111.0 9297500 314.9 299.5 260.6 257.5 P 104.0 9148800 320.4 304.7 252.2 231.2 P 63.7 9034400 312.8 297.3 259.3 248.4 P 40.4 8926800 E 333.8 P 301.7 252.2 236.7 P 29.8 15.3 P -------------------------------------------------------------------------------- O2 O3 O4 O5 | S1 | CL1 | CL2 -------------------------------------------------------------------------------- column total ozone, annual average | sunspot | anthrop. | anthropogenic Arosa N. hemis. equator S. pole | number | chlorine | chlorine in (47N) (25N-50N) (10S-10N) (90S) | | emissions | atmosphere (DU) (DU) (DU) (DU) | | (Mg/yr) | (Mg) --------------------------------------------------------------------------------

P = partial year data only
S = supplementary data from alternative sources/methods
E = estimated from model fit to data

Other notes, caveats on data, and sources:

O1: column total ozone, global average (65°S to 65°N)
combined series from ground-based observations through 1977 and observations from various satellites (Nimbus 7, Meteor 3, GOME, and Earth Probe) from 1978 Ground-based observations have limited spatial coverage; satellite observations may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone. 1958-1977, from Angell, J. K., and J. Korshover, 1989, "Annual and Seasonal Global Variation in Total Ozone and Layer-Mean Ozone, 1958-1987", CDIAC, on line [http://cdiac.ornl.gov/ftp/ndp023/ndp023.txt]; 1978-1992, from "Nimbus 7 TOMS Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/nimbus7/data/zonal_means/ozone/ZM_month_ozone_N7.txt]; 1993-1994, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/meteor3/data/zonal_means/ozone/ZM_month_ozone_M3.txt]; 1995, from M. Weber, 2005, "Monthly and zonal mean GOME WFDOAS total ozone," GOME Homepage, on line [http://www.iup.uni-bremen.de/gome/wfdoas/GOME_WFDOAS_zonal.dat]; 1996-2005, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/eptoms/data/zonal_means/ozone/ZM_month_ozone_ept.txt].

O2: column total ozone, Arosa, Switzerland (47°N)
ground-based measurements from Arosa station Data may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone; observations from a single site may be affected by significant local variations. "Total ozone series in Arosa, Switzerland", Aug. 2004, Environmental Science at the ETH Zurich, on line [http://www.iac.ethz.ch/en/research/chemie/tpeter/totozon.html].

O3: column total ozone, Northern hemisphere midlatitudes (25°N to 50°N)
combined series from several satellites (Nimbus 7, Meteor 3, GOME, and Earth Probe) Satellite observations may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone. 1978-1992, from "Nimbus 7 TOMS Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/nimbus7/data/zonal_means/ozone/ZM_month_ozone_N7.txt]; 1993-1994, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/meteor3/data/zonal_means/ozone/ZM_month_ozone_M3.txt]; 1995, from M. Weber, 2005, "Monthly and zonal mean GOME WFDOAS total ozone," GOME Homepage, on line [http://www.iup.uni-bremen.de/gome/wfdoas/GOME_WFDOAS_zonal.dat]; 1996-2005, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/eptoms/data/zonal_means/ozone/ZM_month_ozone_ept.txt].

O4: column total ozone, equatorial (10°S to 10°N)
combined series from several satellites (Nimbus 7, Meteor 3, GOME, and Earth Probe) Satellite observations may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone. 1978-1992, from "Nimbus 7 TOMS Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/nimbus7/data/zonal_means/ozone/ZM_month_ozone_N7.txt]; 1993-1994, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/meteor3/data/zonal_means/ozone/ZM_month_ozone_M3.txt]; 1995, from M. Weber, 2005, "Monthly and zonal mean GOME WFDOAS total ozone," GOME Homepage, on line [http://www.iup.uni-bremen.de/gome/wfdoas/GOME_WFDOAS_zonal.dat]; 1996-2005, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/eptoms/data/zonal_means/ozone/ZM_month_ozone_ept.txt].

O5: column total ozone, South Pole (90°S)
ground-based observations from the Amundsen-Scott South Pole Station, Antarctica Data may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone at this location; observations from a single site may be affected by significant local variations. "Total ozone data archive: Amundsen-Scott South Pole Station, Antarctica," 2006, NOAA ESRL Global Monitoring Division, on line [http://www.cmdl.noaa.gov/ozwv/dobson/ozone/ams/ams_sel.txt].

S1: annual average sunspot numbers, combined Annual averages. R. A. M. Van der Linden and SIDC, 2005, "Sunspot Data," RWC Belgium, on line at World Data Center for the Sunspot Index, Royal Observatory of Belgium, [http://sidc.oma.be/html/sunspot.html].

C1: Annual anthropogenic chlorine emissions (MG/yr)
total chlorine mass only in emissions of CFC-11, CFC-12, HCFC-22, and methyl chloroform, based on emissions models and production data Data is limited to these four anthropogenic compounds; emissions of most other chlorine-containing compounds are smaller, with the exception of carbon tetrachloride. Stated figures are chlorine only, not the total mass of included compounds. Model-based values involve various assumptions. A. McCulloch, 20 Feb. 2005, "Review of CFC-11: Metadata on Distributed Emissions," GEIA, on line [http://www.geiacenter.org/reviews/cfc11.html]; A. McCulloch, 20 Feb. 2005, "Review of CFC-12: Metadata on Distributed Emissions," GEIA, on line [http://www.geiacenter.org/reviews/cfc12.html]; A. McCulloch, 28 Feb. 2005, "Review of HCFC-22: Metadata on Distributed Emissions," GEIA, on line [http://www.geiacenter.org/reviews/hcfc22.html]; A. McCulloch, 28 Feb. 2005, "Review of Methyl chloroform: Metadata on Distributed Emissions," GEIA, on line [http://www.geiacenter.org/reviews/mcf.html].

C2: Anthropogenic chlorine in atmosphere (Mg)
combined observational (1977-2005) and model-based series for total mass of chlorine in the troposphere associated with CFC-11, CFC-12, HCFC-22, and methyl chloroform Data is limited to these four anthropogenic compounds; quantities of most other chlorine-containing compounds are smaller, with the exception of carbon tetrachloride which accounts for chlorine in quantities about 20% of the listed values from 1977-2005. Stated figures are chlorine only, not the total mass of included compounds. Pre-1977 values are based on a model fit using the emissions data for these four compounds. World Data Centre for Greenhouse Gases, online [http://gaw.kishou.go.jp/wdcgg.html].

O1: column total ozone, global average (65°S to 65°N) combined series from ground-based observations through 1977 and observations from various satellites (Nimbus 7, Meteor 3, GOME, and Earth Probe) from 1978	Ground-based observations have limited spatial coverage; satellite observations may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone.	1958-1977, from Angell, J. K., and J. Korshover, 1989, "Annual and Seasonal Global Variation in Total Ozone and Layer-Mean Ozone, 1958-1987", CDIAC, on line [http://cdiac.ornl.gov/ftp/ndp023/ndp023.txt]; 1978-1992, from "Nimbus 7 TOMS Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/nimbus7/data/zonal_means/ozone/ZM_month_ozone_N7.txt]; 1993-1994, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/meteor3/data/zonal_means/ozone/ZM_month_ozone_M3.txt]; 1995, from M. Weber, 2005, "Monthly and zonal mean GOME WFDOAS total ozone," GOME Homepage, on line [http://www.iup.uni-bremen.de/gome/wfdoas/GOME_WFDOAS_zonal.dat]; 1996-2005, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/eptoms/data/zonal_means/ozone/ZM_month_ozone_ept.txt].
O2: column total ozone, Arosa, Switzerland (47°N) ground-based measurements from Arosa station	Data may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone; observations from a single site may be affected by significant local variations.	"Total ozone series in Arosa, Switzerland", Aug. 2004, Environmental Science at the ETH Zurich, on line [http://www.iac.ethz.ch/en/research/chemie/tpeter/totozon.html].
O3: column total ozone, Northern hemisphere midlatitudes (25°N to 50°N) combined series from several satellites (Nimbus 7, Meteor 3, GOME, and Earth Probe)	Satellite observations may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone.	1978-1992, from "Nimbus 7 TOMS Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/nimbus7/data/zonal_means/ozone/ZM_month_ozone_N7.txt]; 1993-1994, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/meteor3/data/zonal_means/ozone/ZM_month_ozone_M3.txt]; 1995, from M. Weber, 2005, "Monthly and zonal mean GOME WFDOAS total ozone," GOME Homepage, on line [http://www.iup.uni-bremen.de/gome/wfdoas/GOME_WFDOAS_zonal.dat]; 1996-2005, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/eptoms/data/zonal_means/ozone/ZM_month_ozone_ept.txt].
O4: column total ozone, equatorial (10°S to 10°N) combined series from several satellites (Nimbus 7, Meteor 3, GOME, and Earth Probe)	Satellite observations may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone.	1978-1992, from "Nimbus 7 TOMS Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/nimbus7/data/zonal_means/ozone/ZM_month_ozone_N7.txt]; 1993-1994, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/meteor3/data/zonal_means/ozone/ZM_month_ozone_M3.txt]; 1995, from M. Weber, 2005, "Monthly and zonal mean GOME WFDOAS total ozone," GOME Homepage, on line [http://www.iup.uni-bremen.de/gome/wfdoas/GOME_WFDOAS_zonal.dat]; 1996-2005, from "Zonal means", 2006, Total Ozone Mapping Spectrometer, on line [ftp://toms.gsfc.nasa.gov/pub/eptoms/data/zonal_means/ozone/ZM_month_ozone_ept.txt].
O5: column total ozone, South Pole (90°S) ground-based observations from the Amundsen-Scott South Pole Station, Antarctica	Data may be incomplete for some years, which may significantly affect averages due to significant seasonal variations in ozone at this location; observations from a single site may be affected by significant local variations.	"Total ozone data archive: Amundsen-Scott South Pole Station, Antarctica," 2006, NOAA ESRL Global Monitoring Division, on line [http://www.cmdl.noaa.gov/ozwv/dobson/ozone/ams/ams_sel.txt].
S1: annual average sunspot numbers, combined	Annual averages.	R. A. M. Van der Linden and SIDC, 2005, "Sunspot Data," RWC Belgium, on line at World Data Center for the Sunspot Index, Royal Observatory of Belgium, [http://sidc.oma.be/html/sunspot.html].
C1: Annual anthropogenic chlorine emissions (MG/yr) total chlorine mass only in emissions of CFC-11, CFC-12, HCFC-22, and methyl chloroform, based on emissions models and production data	Data is limited to these four anthropogenic compounds; emissions of most other chlorine-containing compounds are smaller, with the exception of carbon tetrachloride. Stated figures are chlorine only, not the total mass of included compounds. Model-based values involve various assumptions.	A. McCulloch, 20 Feb. 2005, "Review of CFC-11: Metadata on Distributed Emissions," GEIA, on line [http://www.geiacenter.org/reviews/cfc11.html]; A. McCulloch, 20 Feb. 2005, "Review of CFC-12: Metadata on Distributed Emissions," GEIA, on line [http://www.geiacenter.org/reviews/cfc12.html]; A. McCulloch, 28 Feb. 2005, "Review of HCFC-22: Metadata on Distributed Emissions," GEIA, on line [http://www.geiacenter.org/reviews/hcfc22.html]; A. McCulloch, 28 Feb. 2005, "Review of Methyl chloroform: Metadata on Distributed Emissions," GEIA, on line [http://www.geiacenter.org/reviews/mcf.html].
C2: Anthropogenic chlorine in atmosphere (Mg) combined observational (1977-2005) and model-based series for total mass of chlorine in the troposphere associated with CFC-11, CFC-12, HCFC-22, and methyl chloroform	Data is limited to these four anthropogenic compounds; quantities of most other chlorine-containing compounds are smaller, with the exception of carbon tetrachloride which accounts for chlorine in quantities about 20% of the listed values from 1977-2005. Stated figures are chlorine only, not the total mass of included compounds. Pre-1977 values are based on a model fit using the emissions data for these four compounds.	World Data Centre for Greenhouse Gases, online [http://gaw.kishou.go.jp/wdcgg.html].