O3 variability in the troposphere as observed by IASI

A study by Wespes et al. (2017) presents global patterns of the main geophysical drivers of IASI O₃ variations, obtained by applying appropriate annual and seasonal multivariate regression models on time series of spatially gridded averaged O₃. They show that the models are able to explain most of the O₃ variability captured by IASI and that they allow identifying clear significant dynamical features (namely NAO, QBO and ENSO) with marked regional differences. They also show that the ENSO perturbs the O₃ variability far from the tropics into mid- and high latitudes where a significant 4-month time-lag in the response of O₃ to ENSO is identified for the first time.