View source for File:Figure 4.18 - Surface ozone by day for Halley, MacMurdo, Neumayer, Sanae, Syowa and South Pole.png

Annual records (against year calendar day) of surface ozone (in parts per billion by volume (ppbv)) for the Southern Hemisphere stations Halley, MacMurdo, Neumayer, Sanae, Syowa and South Pole, reproduced from Helmig et al. (2007<ref name="Helmig et al, 2007">Helmig, D., Oltmans, S., Carlson, D., Lamarque, J.-F., Jones, A.E., Labuschagne, C., Anlauf, K. and Hayden, K. 2007. A review of surface ozone in the polar regions, ''Atmos. Env.'', '''41''', 5138-5161, doi:10.1016/j.atmosenv.2006.09.053.</ref>).
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