Tuesday, 16 January 2007: 2:15 PM
A comparison of AURA/MLS CO measurement with 2 global chemical models
212A (Henry B. Gonzalez Convention Center)
In the troposphere, CO is formed by the incomplete combustion of fossil-fuels and by biomass burning. CO is also formed by the oxidation of CH4 and other hydrocarbons initiated by OH and ozone. The lifetime of CO is a few months in the tropics where there are largest OH mixing ratios. With a lifetime of this magnitude it can serve as a tracer of tropospheric motions. Recent satellite measurements have shown that large plumes of carbon monoxide can reach the upper troposphere through deep convection. Biomass burning in the tropics is a major source of CO and is currently not well represented in the global emission inventories available to the chemical modelling community. To further understand and quantify the impacts of biomass burning and deep convective transport on the chemical constituents in the upper troposphere, comparisons with satellite observations from AURA-MLS were made against two global three-dimensional global air quality models, GEOS-CHEM which is a chemical transport model and GEM-AQ which is an on-line air quality model embedded in GEM, the Canadian wether forecast model . The results show an underestimation of CO during the peak burning seasons, suggesting a deficiency in the emission inventory used in the models. The results of the inter-model and MLS and MOPITT comparisons also reveal dynamical features captured by the models.