A scheme for process-tagged SO4and BC aerosols in NCAR CCM3: Validation and sensitivity to cloud processes

摘要: [1] A life cycle scheme for sulfate (SO4) and black carbon (BC) is implemented in an extended version of the National Center Atmospheric Research (NCAR) Community Climate Model 3 (CCM3). The includes emissions dimethyl sulfide (DMS), SO2, natural anthropogenic origins BC from biomass burning fossil fuel combustion. Chemistry aerosol physics are parameterized based on prescribed oxidant levels background aerosols marine, continental, polar origins. Aqueous chemistry depends estimated exchange rate cloudy clear air. Particulate SO4 tagged by-production mechanisms off-line reconstruction optical water activity properties. With International Panel Change (IPCC), calculations without feedback produce atmospheric turnover times (days) 1.5 (SO2), 3.5 (SO4), 4.7 year 2000 1.6 4.0 2100 A2 emission scenario. modeled SOx compounds compare within a factor 2 with observations at ground level North America Europe free troposphere. For BC, ground-level concentrations well 10 over several regions. too low Arctic winter, which can partly be linked to spurious low-level winter cloudiness. high latitudes, upper tropospheric SO2 largely missing. These major model biases caused by neglected transport scavenging efficiency cumulus clouds. Cloud processes discussed sensitivity tests. found very sensitive vertical convective More research should aim improved cloud parameterization schemes that address key associated reduce uncertainties climate effects aerosols.