Global Variations of Zonal Mean Ozone during Stratospheric Warming Events

Abstract

Eight years of Solar Backscatter Ultraviolet ozone data are examined to study zonal mean ozone variations associated with stratospheric planetary wave (warming) events. These fluctuations are found to he nearly global in extent, with relatively large variations in the tropics, and coherent signatures reaching up to 50° in the opposite (summer) hemisphere. These ozone variations are a manifestation of the global circulation cells associated with stratospheric warming events; the ozone responds dynamically in the lower stratosphere to transport, and pholochemically in the upper stratosphere to the circulation-induced temperature changes. The observed ozone variations in the tropics are of particular interest because transport is dominated by zonal-mean vertical motions (eddy flux divergences and mean meridional transport are negligible), and hence, substantial simplifications to the governing equations occur. The response of the atmosphere to these impulsive circulation changes provides a situation for robust estimates of the ozone-temperature sensitivity in the upper stratosphere.