Phase and Amplitude Relationships Between Ozone, Temperature, and Circulation in the Quasi‐Biennial Oscillation

Abstract The phase and amplitude relationships between dynamical quantities and ozone within the quasi‐biennial oscillation (QBO) are explored. An initial assessment of this is done by applying a principal oscillation pattern analysis to observations (SWOOSH for Ozone) and reanalysis data (ERA5). This analysis highlights features of the ozone and temperature variability including two peaks in amplitude at different heights in the QBO region as well as more subtle phase differences that cannot be explained by a simple QBO theory. We also quantify the sizes of the ozone and temperature advection terms and show that the contribution of background upwelling on variations in the ozone gradient is not negligible . A radiative‐convective equilibrium and photochemical equilibrium model, with the imposed ERA5 QBO variation in upwelling and OSIRIS variations, is used to further understand ozone and temperature changes. The results show that photochemistry and transport are important at all levels, and it is misleading to divide the QBO into separate regimes. Prominent aspects of the variability can be reproduced if ERA5 upwelling is reduced by between 15 and where ERA5 is likely overpredicting the strength of the secondary meridional circulation. Finally, we demonstrate that nonlocality in the vertical plays a major role in QBO dynamics. This arises from ozone transport, the dependence on column ozone of photochemical production, and radiative transfer between layers.