Chemical budgets of the stratosphere

Abstract

A review is given of the stratospheric budgets of odd oxygen, odd nitrogen, nitrous oxide, methane and carbonyl sulfide. The stratospheric column production rate of NO by the reaction N 2O + O( 1D) → 2 NO is 1.1–1.9 × 10 8 molecules cm −2 s −1. The stratospheric loss rates for N 2O, CH 4 and COS are equal to 0.9–1.4 × 10 9, 1 × 10 10 and 0.5 × 10 7 molecules cm −2 s −1, respectively. From currently available information on the global distributions of N 2O and CH 4 there are some indications of about two times smaller OH concentrations below 35 km than those which are calculated based on the latest compilation of kinetic data. Most significantly, however, it is shown that photochemical models and available ozone observations cannot be reconciled and that there may be particularly severe problems in the 25–35 km region. This issue is thoroughly discussed. Volcanic emissions of SO 2 to the stratosphere may locally lead to much enhanced ozone concentrations and heating rates. These may influence the dynamic behaviour of volcanic plumes before their dispersion over large volumes of the stratosphere.