Two‐dimensional model studies of methyl chloroform in the troposphere

The tropospheric measurements, atmospheric release rates, and OH reaction rates for methyl chloroform are consistent with present estimates of the tropospheric OH distribution and a methyl chloroform lifetime of about 5 years. Reaction with OH radicals is found to be the major atmospheric removal process for this species. Although excellent agreement is obtained in the northern hemisphere, recent southern hemisphere observations have indicated a much more rapid growth than can be accounted for by model calculations. A comparison of the two‐dimensional model with simpler formulations such as global, hemispheric or one‐dimensional models, shows that the simpler models may not adequately represent tropospheric transport and removal by OH radicals.