Asian outflow and chemical evolution of ozone and nitrogen oxides over the Pacific Mathew Evans, Daniel Jacob, Harvard Group, TRACE-P Science Team et al.

Questions How well do we understand the behavior of the O3-HOx-NOx system in Asian outflow? What is the relative contribution of different sources on O3 and nitrogen oxides in Asian outflow over the Pacific?

GEOS CHEM vs observations Model sampled along flight tracks Outputs concentrations and rates O3 CO NO NO2 NOy PAN PPN HNO3 OH HO2 RO2 H2O2 CH2O CH3OOH C2H6 C3H8 Acetone Acetaldehyde j(O1D) j(NO2) H2O Temp

Comparison of model and GOME NO2 preliminary slant column K Chance, T Kurosu Smithsonian Astrophysical Observatory R.V. Martin, P.I. Palmer, Harvard

Comparison of model and GOME CH2O preliminary slant column

Model and observed O3 West Mid North South Model / Measurements

Model and observed NO West Mid North South Model / Measurements

Model and observed OH West Mid North South Model / Measurements

NOy to CO Anthropogenic vs Biomass burning sources North South

O3 - PAN relationship Model versus observations (color = Latitude) High latitude Boundary layer Low latitude Free troposphere

Impact of anthro. emissions on March NOx Fractional decrease in NOx when anthropogenic emissions are shut off Fractional decrease in NOx concentration

Impact of anthro. emissions on March O3 Decrease in concentration when anthropogenic emissions are shut off Difference in O3 concentration (ppbv)

O3 model / observed ensemble of TRACE-P data and sensitivity simulations

Preliminary conclusions Distribution of NOx observed during TRACEP is consistent with our understanding of combustion sources Large O3 anthropogenic enhancement in boundary layer Asian outflow with destruction during aging over Pacific. Free tropospheric O3 in Asian outflow has comparable sources from anthropogenic, biomass burning and lightning Large model overestimate of HOx and H2O2 and CH2O??? Mystery VOC source over Hainan???