HR: 09:00h
AN: A21D-05    [Abstracts]
TI: HO$_{x}$ at the South Pole: Measurements and Model Predictions
AU: * Mauldin, L
EM: mauldin@ucar.edu
AF: National Center for Atmospheric Research, 1850 Table Mesa, Boulder, CO 80305 United States
AU: Eisele, F
EM: eisele@ucar.edu
AF: National Center for Atmospheric Research, 1850 Table Mesa, Boulder, CO 80305 United States
AU: Eisele, F
EM: eisele@ucar.edu
AF: Georgia Institute of Technology - School of Earth and Atmospheric Sciences, 311 Ferst St., Atlanta, GA 30332 United States
AU: Kosciuch, E
EM: kosciuch@ucar.edu
AF: National Center for Atmospheric Research, 1850 Table Mesa, Boulder, CO 80305 United States
AU: Henry, B
EM: henry@ucar.edu
AF: National Center for Atmospheric Research, 1850 Table Mesa, Boulder, CO 80305 United States
AU: Davis, D
EM: dpigarden@aol.com
AF: Georgia Institute of Technology - School of Earth and Atmospheric Sciences, 311 Ferst St., Atlanta, GA 30332 United States
AU: Chen, G
EM: g.chen@larc.nasa.gov
AF: NASA Langley Research Center, NASA Langley Research Center, Hampton, VA 23681 United States
AU: Crawford, J
EM: j.h.crawford@larc.nasa.gov
AF: NASA Langley Research Center, NASA Langley Research Center, Hampton, VA 23681 United States
AB: Recent studies have revealed an unexpected and complex chemistry in the lower atmosphere at the South Pole. The combination of low sun angle and low water concentrations would be thought to produce minimal OH concentrations. However during ISCAT-1 and ISCAT-2000, consistently high levels OH were observed and found to be a result of elevated NO levels cycling HO$_{2}$ back into OH. The Antarctic Tropospheric Chemistry Investigation (ANTCI) was conducted at the South Pole during the austral spring of 2003 (22 November to 29 December). This program builds upon the previous ISCAT studies conducted at the South Pole in November-December of 1998 and 2000. Once again elevated levels of OH were observed (peak values of ~4-6 x 10$^{6}$ molecule cm$^{-3}$) and found to correlate with NO concentrations. HO$_{2}$ (HO$_{2}$ + RO$_{2}$) measurements which were interleaved with those of OH, were found to vary as expected in an anti-correlated manner with NO concentrations. Results of measurements and model simulations of OH and HO$_{2}$ will be presented. Special attention will be paid to the occurrence of a partial solar eclipse (86%), during which the concentrations of OH, HO$_{2}$, and NO all responded to the rapid changes in sunlight.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting