The kinetic photochemistry of the Marine Atmosphere

The diurnal kinetic photochemistry of the natural marine atmosphere has been simulated by a series of computations including oxygen-, hydrogen-, nitrogen-, halogen-and carbon-containing species. Concentrations consistent with oceanic data for the `precursor compounds' CH₄, C₂H₂, C₂H₄, C₂H₆, C₃H₆, CO, CH₃Cl, HCl, H₂, NH₃, NO_x, and O₃ result from the calculation. The low concentrations of hydrocarbons and NO_x cause relatively high concentrations of free radicals such as HO ·, HO₂ ·, CH₃O₂ ·, and ClO · and of the radical recombination products CH₃OOH, H₂O₂, and HOCl. Global oceanic fluxes of the precursor compounds are estimated from the amounts required to balance chemical removal. The values for CH₃Cl (1.8×10¹² g/yr) and HCl (2.0×10¹² g/yr) are among the first flux estimates derived to date. The values for CH₄ and total hydrocarbons are small fractions of the total global emission fluxes of these compounds as estimated by alternate techniques. For NH₃ and NO the oceanic source fluxes appear to constitute several percent of total global emissions. The oceanic emission flux for CO (0.3-1.8×10¹⁴ g/yr for two different assumptions of the average background concentration) is a significant fraction (7-39%) of the total global emission flux of this important atmospheric compound.