A side meeting on "Ozone Profile Trend Uncertainty" is planned following the Quadrennial ozone symposium. The meeting aims to address the fundamental question of whether the positive trend of ozone in the post-2000 period is statistically significant or not. Among topics for discussion are uncertainties of ozone trend estimates, statistical tools, comparison between observation and model trend estimates, and next steps for the upcoming WMO ozone assessment of 2018. This meeting is a follow up of the 2011-2014 SPARC/IO3C/IGACO initiative (SI2N).

9 September 2016, 16:00-18:00 and 10 September 2016, 9:00 – 12:00

The University of Edinburgh Outreach Centre, Holyrood Road, Edinburgh, EH8 8AQ

Organisers: Irina Petropavlovskikh, Sophie Godin- Beekmann, Elizabeth Weatherhead, Richard Stolarski, Paul Newman, and Neil Harris.

Proposed presentations:

1. Serge Gullias (UCL) – Presentation of results published by Ah Yeon (ACP) and Kai-Lan (AMT), with emphasis on uncertainties in statistical analysis of data for trends (a functional principal component analysis and stochastic partial differential equation (SPDE) approach with the covariance-based kriging).
2. Jos Laat de (KNMI) – Presentation from the perspective of ozone depletion in the Antarctic Ozone Hole.
3. René Stübi (MeteoSwiss) – Report on the updated trend from Payerne soundings and comparison with those evaluated from the ESA CCI-Ozone satellites records. The problem of “too” short time series to accurately determine the proxies could be also discussed as well as the fact that some proxies have themselves an underlying trend.
4. Roeland Van Malderen (Royal Meteorological Institute of Belgium (RMI), Belgium) – Correction strategies of ozonesonde data and their impact on (simple linear) trends (with 2-sigma uncertainties), and how sampling frequency (once a week vs 3 times a week) affects these trends (by comparing Uccle and De Bilt datasets).
5. Johanna Tamminen (Finnish Meteorological Institute) – Statistical significance of estimated trends in stratospheric ozone profiles.
6. Herman Smit (Research Centre Jülich, Germany) – Uncertainty of ozonesondes, particularly from the most recent ozonesonde-homogenization efforts.
7. Thomas von Clarmann (IMK, KIT) – Desiderata for a community analysis tool, summary of is available from IMK, problems encountered, ongoing activities on uncertainty assessment (particularly of satellite data), etc.
8. Victoria Sofieva (FMI) – ESA Ozone_CCI experience of satellite limb ozone profiles merging and uncertainty characterization.
9. Robert Domadeo (LARC, NASA) – Limitations of the multiple linear regression tool commonly used for trend analysis and how things like diurnal variability, drifts, and sampling patterns fundamentally limit what datasets can be used for these analyses.
10. Daan Hubert (Royal Belgian Institute for Space Aeronomy, Belgium) – The Monte Carlo approach to estimating ozone trend uncertainties.

If you are interested in participating, please contact Irina Petropavlovskikh: