TOTAL OZONE CHANGES OVER THE ANTARCTIC CONTINENT AND 



SOUTHERN OCEAN 



ARLIN J. KRUEGER 



Laboratory for Atmospheres 



NASA-Goddard Space Flight Center 



Greenbelt, MD 20771 



ABSTRACT: Data from the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) are 

 used to measure the change in total ozone over the Antarctic region. During 

 September and October in recent years a pronounced minimum in total ozone has 

 formed over the Antarctic. This minimum, known as the "ozone hole", is a nearly 

 pole centered feature which has deepened and expanded since 1982. Global record 

 low amounts were first found in 1983; these records were broken in 1985 and 1987. 

 The area of ozone hole was larger that the Antarctic continent in the later 

 years. 



Surface fluxes of UV sunlight will increase as the total ozone decreases but the 

 magnitude of the increase depends on the solar zenith angle. Ozone changes late 

 in spring thus have a much larger effect than those taking place in late winter. 

 The average amount of ozone decrease has been computed in October, November, and 

 December using the respective monthly average for the four year period from 1979 

 to 1982 as a reference. During October 1987 the greatest decrease was 140 Dobson 

 units (DU) over the Ross Sea; total ozone over the entire continent decreased by 

 more than 100 DU and changes greater then 50 DU were present over the entire 

 region south of 60 S. The November 1987 decreases were similar to the October 

 decreases in amplitude; the maximum decreases was 140 DU over the coast of Marie 

 Byrd Land centered on 135 E longitude. By December 1987 the larger decreases had 

 dissipated, although nearly the entire southern hemisphere exhibited ozone losses 

 greater than 20 DU; the largest decrease was 60 DU over the Weddell Sea. 



REFERENCES: 



Krueger, A.J., P.E. Ardanuy, F.S. Sechrist, L.M. Penn, D.E. Larko, S.D. Doiron, 

 and R.N. Galimore, 1988. The 1987 Airborne Antarctic Ozone Experiment: The 

 Nimbus 7 TOMS Data Atlas. NASA Ref. Publ . 1201 (March 1988), 245 pp. 



Krueger, A.J., M.R. Schoeberl and R.S. Stolarski, 1987. TOMS observations of 

 total ozone in the 1986 Antarctic spring. Geophys. Res. Lett. 15: 527-530. 



Stolarski, R.S., A.J. Krueger, M.R. Schoeberl, R.D. McPeters, P. A. Newman, and 

 J.C. Alpert, 1986. Nimbus-7 SBUV/TOMS measurements of the spring time Antarctic 

 ozone hole. Nature 322: 808-811. 



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