ANTCI Science Overview

The ANtarctic Tropospheric Chemical Investigation (ANTCI) is a four year NSF supported "collaborative research" program involving ten major institutions. The broad based goal of this program is that of enhancing our understanding of the specific processes that control tropospheric chemical levels and distributions over Antarctica. In our achieving this, it can be expected that our overall understanding of the chemical environment of this major polar region will be vastly improved. These results, in turn, should provide considerable new insight about the atmospheric factors that influence the levels and distribution of several climate proxy species found in Antarctic ice cores. Of particular relevance to this study will be species in the nitrogen and sulfur chemical families.

ANTCI has been designed to build on the findings of two earlier field programs spearheaded by members of this research team, i.e., SCATE (Sulfur Chemistry in the Antarctic Troposphere Experiment) and ISCAT (Investigation of Sulfur Chemistry in the Antarctic Troposhere). Major field studies are scheduled for 2003 and 2005 during the Austral spring/summer months. Specific science objectives include: 1) evaluating the detailed dynamical and chemical processes that control plateau-levels of NO_x/NO_y and OH/HO_x; 2) assessing the representativeness of the geographically limited measurements recorded in earlier field studies (i.e., South Pole and Palmer Station) to the larger polar plateau and the more extensive shoreline areas of Antarctica; and 3) investigating the plateau budgets of nitrogen and sulfur along with the possible role played by the newly identified oxidative OH canopy enshrouding the plateau.

Reflecting the new findings from the earlier ISCAT program, the scope of measurements performed during ANTCI is quite comprehensive. These are being made from ground-based (e.g., Atmospheric Research Obervatory at South Pole), aircraft (Twin Otter) and balloon platforms. The measurement array is most extensive at the ground-based South Pole station and includes the species/parameters, O₃, H₂O, OH, HO₂, H₂O₂, CO, O₃, NO, NO₂, HNO₃, HO₂NO₂, PAN, HONO, NOy, DMS, SO₂, MSA, H₂SO₄, CH₂O, NMHC's, aerosol MS, nss-SO₄^-2, Cl^-, Na⁺, Hg, and Pressure, Temperature, and UV irradiance. Measurement methodologies range from innovative configurations of the chemical ionization mass spectrometry (CIMS) technique (OH, HO₂, HNO₃, HO₂NO₂, SO₂) to state-of-the-science laser-induced fluorescence (LIF) technology (CH₂O, HONO), to several off-the-shelve conventional measurement techniques. With but two exceptions, the above species are sampled simultaneously at a resolution of 5 min or higher. When combined with the available meteorological data, these observations provide an extraordinarily rich database for use as input to interpretive models. The latter range from process oriented box models to regionally focused GCTM's.

In addition to its major advancement of Antarctic atmospheric chemistry, and the new insights it provides to the glaciochemistry community, the ANTCI program should also provide training for five to six new Ph.Ds. Through a continuously updated website and our teacher "outreach program," it will also bring our on-going Antarctic research activity to the attention of other professionals, college and high school students, as well as to the general public. Finally, the data base generated from these studies will be archived, and thus, made available to all USA investigators for further use. It will also be exchanged with international Antarctic research groups such as those operating at the coastal stations at Neumeyer and Halley Bay.