Sensitivity of Global Modeling Initiative chemistry and transport model simulations of radionuclide tracers and ozone to input meteorological data

Chemical transport models (CTMs) are useful tools for studying anthropogenic perturbations to tropospheric composition and chemistry. Large uncertainties exist, however, in model predictions due to the use of different input meteorological fields. We improve our understanding of these uncertainties by incorporating output from the NOAA GFDL's AM3 chemistry-climate model into the Global Modeling Initiative (GMI) modeling framework, where the GMI CTM can also be driven by several other meteorological fields (e.g., fvGCM, GEOS-4 DAS, and GEOS5-MERRA). We characterize transport of radionuclide tracers (222Rn, 210Pb, and 7Be) in the GMI/AM3 simulations in comparison with those simulations driven by other meteorological datasets and with long term observational datasets for radionuclide tracers. We assess the cross-tropopause transport of 7Be in all simulations and discuss the consequences for model predictions of tropospheric ozone. The GMI model full-chemistry simulations are evaluated with ozone climatology from ozonesonde measurements and tropospheric ozone columns determined from the satellite (TOMS/SBUV and OMI/MLS) measurements. In particular, we test the model's capability to reproduce the mid-tropospheric O3-CO correlations observed by the Tropospheric Emission Spectrometer (TES) aboard the EOS Aura satellite. Discrepancies in the O3-CO correlations simulated with different meteorological fields will be discussed.