Results from the ANTCI 2005 Antarctic Plateau Airborne Study

The 2005 Antarctic Tropospheric Chemistry Investigation (ANTCI 2005) was conducted from late November to mid December 2005. Extensive sampling of the Antarctic Plateau was performed on five of the twelve research flights. The measurements made during those flights extend the database of NO and NMHC observations made during the ANTCI 2003 mission and provide airborne measurements of O3, HNO3, HO2NO2, and SO2 across the Plateau. Vertical chemical profiles compiled from all five Plateau-focused flights are presented. Comparisons with South Pole measurements are made where appropriate. NO, HNO3, and HO2NO2 concentrations all exhibited strong vertical trends with the highest levels observed closest to the surface. Horizontal chemical profiles from the two most geographically diverse flights are also presented. The movement of a high pressure ridge across Antarctica during the study period provided for very different meteorological conditions during these two flights as well, which makes ascription of the differences in chemistry challenging. Although concentrations of short-lived species varied across the Plateau, they were still higher than would be expected in the remote troposphere. This confirms the fact that the Plateau can be considered an expansive chemical reactor. Lastly, the results of a brief firn air experiment conducted at Midpoint C are presented for comparison with South Pole and Summit, Greenland snow experiments.