Variability of Reactive Nitrogen Species linked to the stratospheric

Variability of Reactive Nitrogen Species linked to the stratospheric QBO
Mijeong Park, National Center for Atmospheric Research, Boulder, CO
In the stratosphere, reactive nitrogen species, including nitrogen oxides (NO and NO2, collectively
NOx) are produced through the oxidation of nitrous oxide (N2O) and are closely linked with
stratospheric ozone (O3) through catalytic loss processes. Interannual variability of nitrogen species
and O3 are strongly influenced by the stratospheric quasi-biennial oscillation (QBO) in the tropical
stratosphere. In this study, we examine variability of nitrogen species, and their links with O3, using
over 10 years of satellite measurements from the Optical Spectrograph and InfraRed Imaging System
(OSIRIS) instrument onboard the Odin spacecraft, together with the Aura Microwave Limb Sounder
(MLS). We furthermore compare observations with simulations from the Whole Atmosphere
Community Climate Model (WACCM4) global chemistry-climate model. Simulations of nitrogen
species from WACCM4 enable a comprehensive analysis of the reactive nitrogen budget and
variations linked to the QBO, and we find good agreement with observations. The model also shows
evidence for coherent changes in the lower stratosphere associated with El Nino - Southern Oscillation