New paper about global tropospheric ozone changes assessment

The paper entitled “Recent tropospheric ozone changes – A pattern dominated by slow or no growth” by Oltmans et al. (2013) has been recently published in Atmospheric Environment.

The full reference is:

Oltmans, S., Lefohn, A., Shadwick, D., Harris, J., Scheel, H. Galbally, I., Tarasick, D., Johnson, B., Brunke, E., Claude, H., Zeng, G., Nichol, S., Schmidlin, F., Davies, J., Cuevas, E., Redondas, A., Naoe, H., Nakano, T., and Kawasato, T.: Recent tropospheric ozone changes – A pattern dominated by slow or no growth, Atmos. Environ., 67, 331–351, 2013.

This paper is the latest review and summary of the observations of tropospheric ozone on a global scale.

Longer-term (20–40 years) tropospheric ozone (O₃) time series obtained from surface and ozonesonde observations have been analyzed to assess possible changes with time through 2010. The long-term surface ozone record of Izaña GAW station has been included in this study.

Main results:

1. Many of the longer time series (∼30 years) in mid-latitudes of the Northern Hemisphere show a pattern of significant increase in the earlier portion of the record, with a flattening or even declining over the last 10–15 years.
2. In the southern hemisphere subtropics and mid-latitudes, the significant increase observed in the early part of the record has leveled off in the most recent decade.
3. At the South Pole, a decline observed during the first half of the 35-year record has reversed, and O₃ has recovered to levels similar to the beginning of the record.
4. Although there are still many uncertainties about the causes of the longer-term changes, It appears that in the mid-latitudes of the northern hemisphere, controls on O₃ precursors have likely been a factor in the observed leveling off or decline from earlier O₃ increases.

The paper is available here.