Tropospheric Chemistry and Climate Impacts of VSL Halogens: Pre-Industrial to Present day

DOUGLAS E. KINNISON; ALFONSO SAIZ-LOPEZ; JEAN-FRANCOISE LAMARQUE; CARLOS ORDOÑEZ; RAFAEL PEDRO FERNÁNDEZ; SIMONE TILMES

Viena

Conferencia; European Geosciences Union General Assembly - (EGU 2013); 2013

European Geosciences Union

Ozone in the troposphere is one of the most important short-lived gases contributing to greenhouse radiative forc-ing (IPCC, 2007) and is of central importance to the chemistry of this region of the atmosphere. Tropospheric ozone is produced by photochemical oxidation of carbon monoxide, methane and non-methane volatile organic compounds in the presence of nitrogen oxide. A large fraction of the tropospheric ozone loss occurs within the tropical marine boundary layer via photolysis to excited oxygen atoms followed by reaction with water vapor, re-actions with odd hydrogen radical, and surface deposition. In addition, inorganic halogens (i.e. chlorine, bromine, and iodine species) are known to destroy ozone through efficient catalytic reaction cycles. In this study, we usethe NCAR 3D chemistry climate model (CAM-CHEM). The model has a full representation of tropospheric and stratospheric chemistry. Its scope has been extended to include halogen sources, reactive halogen chemistry, and related atmospheric processes (Ordonez et al. 2012; Saiz-Lopez et al. 2012). The purpose of this work is to contrast the pre-industrial importance of tropospheric halogen driven ozone loss to present day conditions; specifically the importance of iodine chemistry.