Evidence for photochemical production of ozone at the South Pole surface

Observations of OH, NO, and actinic flux at the South Pole surface during December 1998 suggest a surprisingly active photochemical environment which should result in photochemical production of ozone. Long-term South Pole in situ ozone data as well as sonde data also appear to support this conclusion. Other possible factors contributing to ozone variability such as stratospheric influence and the origin of air transported to the South Pole are also explored. Based on box model calculations it is estimated that photochemistry could add 2.2 to 3.6 ppbv/day of ozone to surface air parcels residing on the Antarctic polar plateau. Although the oxidizing potential of the polar plateau appears to be exceptionally high for a remote site, it is unlikely that it has a significant impact on surrounding regions such as the Southern Ocean and the Antarctic free troposphere. These new findings do suggest, however, that the enhanced oxidizing power of the polar plateau may need to be considered in interpreting the chemical history of climate proxy species in ice cores.