Evidence for a CO increase in the SH during the 20th century based on firn air samples from Berkner Island, Antarctica

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Assonov, S. S., Brenninkmeijer, C. A. M., Jöckel, P., Mulvaney, R., Bernard, S., Chappellaz, J.
• Format: Text
• Language: English
• Published: 2018
• Subjects: Antarctic; Berkner Island; Antarc*; Antarctica
• Online Access: https://doi.org/10.5194/acp-7-295-2007; https://www.atmos-chem-phys.net/7/295/2007/

Trends of carbon monoxide (CO) for the past 100 years are reported as derived from Antarctic firn drilling expeditions. Only one of 3 campaigns provided high quality results. The trend was reconstructed using a firn air model in the forward mode to constrain age distributions and assuming the CO increase to be proportional to its major source, namely CH 4 . The results suggest that CO has increased by ~38%, from 38±7 to 52.5±1.5 ppbv over a period of roughly 100 years. The concentrations are on the volumetric scale which corresponds to ~1.08 of the scale used by NOAA/CMDL. The estimated CO increase is somewhat larger than what is estimated from the CO budget estimations and the CH 4 growth alone. The most likely explanation might be an increase in biomass burning emissions. Using CH 3 Cl as another proxy produces a very similar reconstruction.