HR: 0800h
AN: A51C-0074    [Abstracts]
TI: Lagrangian Model of the Sacramento Urban Plume
AU: * Becking, S G
EM: lubluvas@yahoo.com
AF: University of California at Berkeley, Department of Chemistry, Latimer Hall, Berkeley, CA 94720 United States
AU: Murphy, J G
EM: j.g.murphy@uea.ac.uk
AF: University of East Anglia, School of Environmental Sciences, Norwich, NR4 7TJ United Kingdom
AU: Cohen, R C
EM: cohen@cchem.berkeley.edu
AF: University of California at Berkeley, Department of Chemistry, Latimer Hall, Berkeley, CA 94720 United States
AU: Dillon, M
EM: dillon7@llnl.gov
AF: Lawrence Livermore National Laboratory, Atmospheric Science Division, PO Box 808, L-103, Livermore, CA 94551 United States
AU: Day, D
EM: daday@ucdavis.edu
AF: University of California at Davis, Land, Air and Water Resources Departmnet, Davis, CA 95616 United States
AU: Cleary, P
EM: patricia@chemistry.leeds.ac.uk
AF: University of Leeds, School of Chemistry, Leeds, LS2 9JT United Kingdom
AU: Wooldridge, P J
EM: pjwool@socrates.berkeley.edu
AF: University of California at Berkeley, Department of Chemistry, Latimer Hall, Berkeley, CA 94720 United States
AU: Schade, G W
EM: schade@ariel.met.tamu.edu
AF: Texas A&M University, Department of Atmospheric Sciences, College Station, TX 77843 United States
AU: Millet, D B
EM: millet@eps.harvard.edu
AF: Harvard University, Department of Earth and Planetary Sciences, Cambridge, MA 02138 United States
AU: Goldstein, A
EM: agoldstein@nature.berkeley.edu
AF: University of California at Berkeley, Department of Environmental Science, Policy, and Managment, Berkeley, CA 94720 United States
AB: To better understand the Sacramento urban plume evolution, measurements of hydrocarbons, nitrogen oxides, and ozone were obtained during summer 2001 near the University of California Blodgett Forest Research Station (UC BFRS) on the western slope of the Sierra Nevada Mountains and at Granite Bay, an eastern suburb of Sacramento. The measurements were used to constrain a Lagrangian plume model coupled to a full photochemical model. Model input included the temperature, pressure, boundary layer height, deposition rate of HNO₃, concentration of H₂O, appropriate rate constants, estimates of the background concentrations of VOC, NOy, O₃, CO, and the concentrations of these chemicals at Granite Bay at time=0 and at UC BFRS at time=5 hours. Fitting to the data using a nonlinear least squares routine where the only adjustable parameters are the dilution rate and the H₂CO concentration, we find that the dilution rate was 0.37 hr^-1, and the formaldehyde concentration was 11 ppb. We varied the branching ratio to alkyl nitrate production and found an optimum at a value of 0.03. The model predicts an average OH concentration of 3.0 × 10⁶ molecules/cm³.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005