Physically based inversion of surface snow concentrations of H2O2 to atmospheric concentrations at South Pole

Inversion of chemical records archived in ice cores to atmospheric concentrations requires a detailed understanding of atmosphere-to-snow-to-ice transfer processes. A unique year-round series of surface snow samples, collected from November, 1994 through January, 1996 at South Pole and analyzed for H2O2, were used to test a physically based model for the atmosphere-to-snow component of the overall transfer function. A comparison of photochemical model estimates of atmospheric H2O2, which are in general agreement with the first measurements of atmospheric H2O2 at South Pole, with the inverted atmospheric record (1) demonstrate that the surface snow acts as an excellent archive of atmospheric H2O2 and (2) suggest that snow temperature is the dominant factor determining atmosphere-to-surface snow transfer at South Pole. The estimated annual cycle in atmospheric H2O2 concentration is approximately symmetric about the summer solstice, with a peak value of similar to 280 pptv and a minimum around the winter solstice of similar to 1 pptv, although some asymmetry results from the springtime stratospheric ozone hole over Antarctica.