HR: 1340h
AN: A33D-1541    [Abstracts]
TI: Photochemical Activity in Mexico City during MILAGRO 2006: results from the T1 site
AU: * Case Hanks, A T
EM: anne.case@gatech.edu
AF: Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA 30332,
AU: Huey, L
EM: greg.huey@eas.gatech.edu
AF: Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA 30332,
AU: Tanner, D
EM: dtanner@eas.gatech.edu
AF: Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA 30332,
AU: Vargas, O
EM: ovargas@eas.gatech.edu
AF: Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA 30332,
AU: Sjostedt, S
EM: ssjosted@chem.utoronto.ca
AF: University of Toronto, Department of Chemistry, Toronto, ON M5S 3H6, Canada
AU: Olson, J R
EM: jennifer.r.olson@nasa.gov
AF: NASA Langley Research Center, NASA Langley Research Center, Hampton, VA 23681, United States
AU: Chen, G
EM: g.chen@nasa.gov
AF: NASA Langley Research Center, NASA Langley Research Center, Hampton, VA 23681, United States
AU: Lefer, B
EM: blefer@uh.edu
AF: University of Houston, Geosciences Department, Houston, TX 77204, United States
AU: Blake, D R
EM: drblake@uci.edu
AF: University of California Irvine, Department of Chemistry, Irvine, CA 92697, United States
AB: A large suite instruments were deployed at a ground based site in Tecámac, México (near the northern boundary of Mexico City) to measure SO₂, NO, CO, O₃, H₂SO₄, OH and HO₂ +RO₂ during MIRAGE-Mex field campaign (March 2006). These and other measurements are used to characterize atmospheric oxidation and predict sulfuric acid and OH concentrations at the site. The observations in conjunction with the NASA LARc Photochemical box model are used to explore ozone production, nitrate and sulfate formation, and radical levels and radical production rates during the day. The 1-minute predicted OH values agreed well with observations (R² = 0.88). Maximum ozone production was calculated to be 25 ppb/hr and 30 ppb/hr from the observations and model predictions, respectively. Most of the photochemical activity is dominated by the radical fluxes in the morning hours, nitrate formation peaks around 10 am LST; this early morning peak is also seen in ozone production. Although the diurnal model predictions agree well with measured species (HO₂ + RO₂ radical Model/observed (M/O) ~0.85 and OH M/O ~ 0.98), there is disagreement between the model and observations within the early morning.
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting