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’ CH 4 , C 2 H 2 , C 2 H 4 , C 2 H 6 , C 3 H 6 , CO, CH 3 Cl, HCl, H 2 , NH 3 , NO x , and O 3 result from the calculation. The low concentrations of hydrocarbons and NO x cause relatively high concentrations of free radicals such as HO ·, HO 2 ·, CH 3 O 2 ·, and ClO · and of the radical recombination products CH 3 OOH, H 2 O 2 , and HOCl. Global oceanic fluxes of the precursor compounds are estimated from the amounts required to balance chemical removal. The values for CH 3 Cl (1.8×10 12 g/yr) and HCl (2.0×10 12 g/yr) are among the first flux estimates derived to date. The values for CH 4 and total hydrocarbons are small fractions of the total global emission fluxes of these compounds as estimated by alternate techniques. For NH 3 and NO the oceanic source fluxes appear to constitute several percent of total global emissions. The oceanic emission flux for CO (0.3–1.8×10 14 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.