Figure 5: Covariance in mean ozone aloft in association with the Mt. Pinatubo eruption.

12-Month running mean anomalies (relative to the record mean) of lower-stratospheric to mid-tropospheric ozone above Edmonton in Southern Canada for 1980–2012. Symbols denote the averages of available weekly samples: from ozonesondes at 250–150 hPa (black circles) and 520–380 hPa (grey diamonds), and from the model at 250–150 hPa (orange circles). Solid lines show the model ‘true averages’ of continuous daily sampling for ozone at 250–150 hPa (red) and tracer of stratospheric ozone at 520–380 hPa (blue).