1. ANTCI Overall Objective To provide a more comprehensive understanding of Antarctic atmospheric chemistry with the goal of providing new insights related to the interpretation of the levels and distributions of C, S, and N climate proxy species contained within ice cores

2. Specific Scientific Objectives: Evaluate the detailed chemical and dynamical processes that control spring/summertime levels of NO x /NO y and OH/HO x at South Pole. Evaluate the detailed chemical and dynamical processes that control spring/summertime levels of NO x /NO y and OH/HO x at South Pole. Assess the representativeness of South Pole fast photochemistry, as driven by photodenitrification of snow, to the larger polar plateau region Assess the representativeness of South Pole fast photochemistry, as driven by photodenitrification of snow, to the larger polar plateau region Investigate the relative importance of the oxidative processes involved in the coast-to- plateau transport of reduced sulfur and determing the principal regions of chemical transition. Investigate the relative importance of the oxidative processes involved in the coast-to- plateau transport of reduced sulfur and determing the principal regions of chemical transition.

3. Secondary Objectives: Investigate snow/firn chemical species that undergo extensive exchange with the atmosphere (e.g., NO x, HNO 3, CH 2 O, H 2 O 2, monocarboxylic acids). Investigate snow/firn chemical species that undergo extensive exchange with the atmosphere (e.g., NO x, HNO 3, CH 2 O, H 2 O 2, monocarboxylic acids). Assess the different chemical forms of the trace element Hg and their relationship to the levels of O 3, OH and other potential oxidants. Assess the different chemical forms of the trace element Hg and their relationship to the levels of O 3, OH and other potential oxidants.

4. Questions Which Remain ● Why does NOx increase at SP when the wind is from the east? ● How does a shift away from a 24 hr constant sun light environment affect the emission rate of NOx on the plateau? ● How does NO x decrease as it flows toward the coast? Upward Mixing, Diurnal Cycling, Surface Chemistry, Other? ● Where does the reactive nitrogen observed at the Pole come from? Stratosphere, Lightening in the Southern Oceans? ●How do oxidation rates [OH] change with altitude and geographical location over the plateau, i.e. what is the range of the OH oxidizing canopy? ● Where is the MS/SO 4 = ratio determined? Near the coast at higher altitudes or gradually as sulfur is transported inland, i.e. why is this ratio typically 0.07 over most of the plateau?

5. ● Are NO, NO 2, CH2O, H2O2 and other compounds emitted from the snow surface over the whole plateau region? Near the coast? ●How much of the nitrogen formed over the continent flows out of glacial valleys to the sea General Questions: ●What can we learn about transport from reactive and passive chemical tracers? ●How much is the MS/SO 4 = ratio effected by deposition location as opposed to sulfur sources or temperature?

6. ANTCI 2005 Flight Missions and Constrains We have 1 Otter from ~Nov. 14 – Dec. 17 Missions: We have proposed ~ 14 flights out of McMurdo & 4 out of the South Pole (7 days at the South Pole - 2 flights to Weddell Sea, 1 to Max alt., & 1 return to McMurdo) Constrains: Fuel along Ross coast, low latitude, and maybe for Weddell Sea

8. Boundary Layer Inflow ANTCI 2005

9. Compound InvestigatorTechniqueSensitivity HNO3 HueySICIMS 5 pptv HO2NO2HueySICIMS SO2HueySICIMS Aerosol SO4,MS, NO3? Huey Weber PILS-IC /CNN 1 pptv ? OHEisele/MauldinSICIMS 1x10 5 mol/cm 3 HO2/RO2Eisele/MauldinSICIMS 5x10 5 mol/cm 3 H2SO4Eisele/MauldinSICIMS 1x10 5 mol/cm 3 MSAEisele/MauldinSICIMS NO Buhr/DavisChemiluminescence 5 pptv NO y Buhr/DavisChemiluminescence 10 pptv DMS Blake Grab sample GC/MS 1 pptv NMHC& HC Blake Grab sample GC/MS 0.1-1 pptv Actinic flux Shetter/LeferSpectroradiometerN/A Twin Otter Measurements

11. Flight LocationDescriptionFlight Time McM-McMSouth along Ross Sea coast & up Byrd Glacier & return (refuel if possible)6 if possible McM-McMSouth along Ross Sea coast & up Byrd Glacier & return (refuel if possible)4 McM-McM NO loss, flight to 75 S/150 E (or further Northeast, refuel if possible)6 if at all possible McM-McMSouth along Ross Sea coast & up Byrd Glacier & return (refuel if possible)6 if possible McM-Vostok-McMOutflow & sulfur sub. (refuel at TAMSEIS11 McM-McMIce shelf and ice edge survey4 McM-McMUp coast to Terra Nova and return (refuel if possible)6 if possible McM-McMIce shelf and ice edge survey4 McM-McMUp coast to Terra Nova and return (refuel if possible)6 if possible McM-SPPlateau & outflow 3 refueling stop (Ref. J. English,Seismic,TAMSEIS,AGO4) 10 SP-Weddell Sea-SPIn/out flow. Refueling stop on the way out and back at the same site11 SP- 82 S/75 E -SPsubsidence flight to about 82 S /75 E. Refueling stop on the way out & back at AGO4 11 SP-Weddell Sea-SPIn/out flow. Refueling stop on the way out and back at the same site11 SP-McMLow altitude outflow. 3 refueling stops (Ref. J. English,Seismic,TAMSEIS,AGO4) 10 McM-McMSouth along Ross Ice Shelf to Byrd Glacier and return6 McM-McMUp coast to Terra Nova and return4 McM-McMSouth along Ross Ice Shelf to Byrd Glacier and return6 McM-McMIce shelf and ice edge survey4 TotalThe flight campaign will start and end at McMurdo126 LC-130 Fuel Flight LC-130Airdrop fuel at AGO2/LaPaz Icefields8