Atmospheric Chemical Transport Models - Examples and Measurement Systems 2

(c) Methane Simulations using MATCH: Y. Chen, Ph.D. Thesis, contd. CH4 Observational Sites (1996-2001) Ref: Chen & Prinn, J. Geophys. Res., 2005, doi:10.1029/2004JD005542 Reference Simulation (color) vs. Observed (black) CH4 at 5 AGAGE Sites MATCH Simulates Effects of ENSO Transport on CH4 at Samoa AGAGE observations versus MATCH model at Samoa El Nino winds MIRROR PLOT La Nina winds MIRROR PLOT Chen & Prinn, J. Geophys. Res., in press, 2005 MATCH simulates effect of North Atlantic Oscillation on CH4 AGAGE Observations versus MATCH Model at MaceHead, Ireland MIRROR PLOT NAO plus MIRROR PLOT NAO minus (d) Dimethyl Sulfide-Aerosol Connections MSA is CH3SO2OH DMSO DMSO2 MSA oxidation condensation condensation DMS is CH3SCH3 activation DMS cloud droplet oxidation condensation SO2 evaporation evaporation condensation oxidation = gas-phase CCN growth H2SO4 = aerosol/cloud CN nucleation Motivation for new chemical mechanisms altitude (km) Original mechanism does a poor job simulating aircraft data (red dots) time (hours) altitude (km) Modified mechanism does a better job (model is black dots with grey model error bars) time (hours) DMS Oxidation Mechanism Increasing Oxidation and Solubility, Decreasing Chemical Reactivity Arrows: White=Basic Mechanism, Red & Yellow=New Pathways HO2 O O O2 CH3SCH3 CH3SCH3 HO2 O OH OH CH3 O CH3SOH O H2SO4 C2 C1 O2 H2O O O NO2 CH3SOO CH3SOONO2 O O NO2 NO CH3SO3 O3 O2 NO2 NO Iso CH3 OH CH3SOO O CH3SCH3 O CH3SOH HO2 OH OH H2O CH3SCH2 OH C1 O2 CH3SCH3 SO3 O2 OH CH3SCH3 CH3SOH CH3 HO2 OH H-abstraction H2O CH3SCH2OO NO2 CH3SCH2O O3 NO2 NO2 O O CH3SOONO2 CH3SOO NO2 NO O2 NO CH3 O2 CH3SO SO2 OH-addition NO CH3SO2 H2O OH O2 O2 O3 NO2 NO NO2 CH3SOO O2 NO O2 CH2O CH3S Iso NO2 CH3SOONO2 MATCH MODEL RUNS:DMS Emissions Image removed due to copyright considerations. See Figure 1. Lucas, D.D. and R.G. Prinn, Sensitivities of gas-phase dimethylsulfide oxidation products to the assumed mechanisms in a chemical transport model, Journal of Geophysical Research, 110, D21312, doi:10.1029/2004JD005386, 2005.