The CH⁴ concentration over the ocean and its possible variation with latitude

Abstract

Measurements of the CH₄ concentration over the North Atlantic and the Pacific are presented. The Pacific data indicate a difference of about 0.1 ppmv between Northern and Southern Hemispheres. From this difference and a plausible distribution of CH₄ sources a tropospheric CH₄ lifetime between 3.5 and 11 years is estimated.