Time Scales in Atmospheric Chemistry: Coupled Perturbations to N 2 O, NO y , and O 3

Abstract

Nitrous oxide (N 2 O) is one of the top three greenhouse gases whose emissions may be brought under control through the Framework Convention on Climate Change. Current understanding of its global budget, including the balance of natural and anthropogenic sources, is largely based on the atmospheric losses calculated with chemical models. A representative one-dimensional model used here describes the photochemical coupling between N 2 O and stratospheric ozone (O 3 ), which can easily be decomposed into its natural modes. The primary, longest lived mode describes most of the atmospheric perturbation due to anthropogenic N 2 O sources, and this pattern may be observable. The photolytic link between O 3 and N 2 O is identified as the mechanism causing this mode to decay 10 to 15 percent more rapidly than the N 2 O mean atmospheric lifetime, affecting the inference of anthropogenic sources.