Interannual variability of stratospheric and tropospheric ozone determined from satellite measurements

Long-term satellite records have been used in previous studies to examine both trends and interannual variability (IAV) of ozone in the stratosphere. In this study, we use satellite measurements to produce long-term records of both tropospheric and stratospheric ozone and we examine the IAV of these data sets. Our analysis of the stratospheric component of these observations is consistent with previous findings for total ozone that show a strong correlation with the quasi-biennial oscillation (QBO) at low latitudes. For tropospheric ozone, we find that there are strong regional enhancements due to in situ generation from large emissions. The IAV of some of these regional enhancements, on the other hand, are strongly correlated with the phase of El Nino-Southern Oscillation (ENSO) and are consistent with our understanding of how regions of subsidence are more conducive to the in situ production of ozone pollution. The insight gained from this study will hopefully provide a better understanding between prevailing meteorological conditions and the evolution of widespread ozone episodes on shorter timescales with the eventual goal of producing an air quality forecasting capability so that exposure of the human population to elevated levels of ozone can be reduced.