Member of the Helmholtz-Association Tropospheric Ozone Changes Preliminary Workshop Summary Toulouse, April 2011

Member of the Helmholtz-Association Tropospheric ozone change from preindustrial to present % Gauss et al., 2006 (ACP) 4/10 models

Tarasova

Member of the Helmholtz-Association

Agenda Monday Session 1 – Data analysis in the UT/LS, global analysis Poster Session Session 2 – Data analysis over Asia Tuesday Session 3 – Data analysis over SH and Tropics Session 4 – Updates of analyses over North America and Europe Session 5 – Discussion session: State-of-the-art and future needs Wednesday Session 6 – Evaluation of long-term model runs Session 7 – Common methodologies and standard data sets

Member of the Helmholtz-Association

Tropospheric Ozone Standard Deviation o N TOTAL STRATOS ANTHRO Solid: Intregated Below 300 hPa Dotted: At 500 hPa Dashed: At Surface Stratosphere Explains Large Scale Variance Stratosphere Explains 81% of the area averaged variance at 500 hPa Stratosphere Explains 77% of the area averaged variance at surface Stratosphere Explains Much Less of Site Level Variance Stratosphere Explains on average 50% of variance at particular sites at 500 hPa Stratosphere Explains 25% of the variance at particular sites at surface Hess&Zbinden

Asian measurements Arshinov: „TOR“ Siberia Logan: Japan summaryCristofanelli: NepalX. Xu: Mt. WaliguanZbinden: Japan Naha=tropical

Cape Grim Surface Ozone Seasonal Trend Analysis based on monthly anomalies. Surface ozone in Austral spring (SON) and summer (DJF) show positive trends in the 1980’s and 1990’s and non-significant trends in the 2000’s and positive trends over the three decades combined Surface ozone in Austral autumn (MAM) and winter (JJA) show non-significant trends in each of the three decades. Over the three decades there are ambivalent results concerning an upward trend in these seasons. Galbally Southern Hemisphere and Tropics

Luppo and Cupeiro Overlaying Ushuaia, Cape Point and Cape Grim gives very coherent time series

Tropical upper troposphere Morioka et al. SHADOZ MOZAIC Cammas et al.

Member of the Helmholtz-Association Europe Gilge MOZAIC Sondes Logan

Member of the Helmholtz-Association US surface ozone trends Lefohn Trend depends on the metrics you choose

Member of the Helmholtz-Association How well do we model tropospheric ozone? Stevenson et al (ACCENT)

Member of the Helmholtz-Association M. Lin

Member of the Helmholtz-Association Publication(s) Collect and post presentations: default=use what’s there, updates by 30 April Proceedings! Oksana to provide template very soon; deadline for submission: mid June IGAC Newsletter: deadline mid August; also consider SPARC newsletter, deadline November – don’t forget EOS Review article(s). HTAP (Parrish), ACCENT plus (Monks), « global » review article? Discussion: way forward of this initiative Database(s) Identify suitable data sets as common starting point for modelers: Define core (or benchmark) subset with sufficient density and quality … !

Member of the Helmholtz-Association Future activities (discussion not concluded yet) Establish expert-team on tropospheric ozone in GAW Establish specific tasks (O3 sondes reana, databases; metrics/diagnostics, transcom process…) Organize task meetings Another big workshop? Opportunities: -Ozone symposium Toronto (August 2012) -ACCENT Plus (Urbino)

Member of the Helmholtz-Association (Common) method for model evaluation ? Common period ? Background ? Quantitatively / qualitatively Differences surface/FT/UT/LS Main processes & emissions : how well are they reproduced ?  Seasonal behaviors  Strat-trop exchanges  El-Nino  Climate changes ? (GHG, O3 hole/recovery)  Asian emissions ?

M.J. Prather, X. Zhu, Q. Tang, J. Hsu, J.L. Neu (2011), An atmospheric chemist in search of the tropopause, J. Geophys. Res., 116: D04306, doi: /2010JD UTLS ozone: a new definition for the tropopause „e90“ tropopause

Oman et al. Ziemke Ozone ENSO Index

Member of the Helmholtz-Association Summary statements Datasets: Network density and length of time series rather inhomogeneous across the world Europe has probably highest density: yet issues with consistency Data sampling frequency remains a problem for free troposphere

Member of the Helmholtz-Association Summary statements (Global) Models: can successfully reproduce seasonal cycles and magnitude of tropospheric ozone more and more models capture some aspects of interannual variability, in particular in free troposphere fail to reproduce decadal surface ozone changes (when compared to „key data sets“) Reasons unclear  need a more systematic community approach (AEROCOM strategy) Topics: strato. (STE) changes, biogenic emissions, vertical mixing, emission changes, chemical processes(?)

Member of the Helmholtz-Association Summary statements General: More focus on variability and „patterns“ rather than trends Avoid the term „background“ Need to assess climate variability before attributing trends Try to make use of the momentum of an assessment? Tropospheric ozone is (still) very interesting!