Stratospheric Processes and their Role in Climate (SPARC)

1. Stratospheric Processes and their Role in Climate (SPARC) A Core Project of the World Climate Research Programme Co-Chairs: Ted Shepherd and Tom Peter SPARC Themes

2. World Climate Research Programme (WCRP) Objectives • Study climate system, determine its variability and predictability • Determine human influence on climate

3. World Climate Research Programme (WCRP)

4. CLIVAR 1995  SPARC 1992 WGNE WGCM CliC 2000 GEWEX 1988 

5. CLIVAR 1995  Atmospheric Chemistry and Climate (AC&C) SPARC 1992 WGNE WGCM CliC 2000 GEWEX 1988  SOLAS

6. SPARC’s Overall Aim & Modus Operandi To bring knowledge of the stratosphere to bear on relevant issues in climate variability and climate prediction To identify “bite sized” deliverables in a well-defined strategic plan for evolution

7. SPARC vehicles include SPARC Newsletter (194 citations in the WoS) SPARC Reports (105 citations in the WoS) Refereed review papers Interdisciplinary workshops to cross boundaries Working groups, e.g. data assimilation, dynamic variability, and many more General Assemblies (every 4 years) Next one is in Bologna, Italy, August 31–September 5, 2008

8. SPARC Reports have had a particularly important role in past assessments Ozone profile trends Stratospheric temperature trends Water vapour trends Aerosol assessment Provided direct input into the last three WMO/UNEP Ozone Assessments (14 citations in WMO/UNEP 2006; 7 citations in AR4)

9. SPARC has continually evolved, largely dynamics-oriented at start, has recently Recognized need for coupled chemistry, initiated links to IGAC Recognized importance of data assimilation for climate studies and brought in the academic community Recognized potential of cloud-resolving models to exploit high-resolution measurements in the Tropical Tropopause Layer (TTL)

10. Structure of the SPARC Programme

11. CCMVal Activity • http://www.pa.op.dlr.de/CCMVal/ • Over the past 3 years CCMVal hasengaged in a comprehensive assessment of the current generation of Chemistry-Climate Models (CCMs) to support: • WMO/UNEP 2006 Assessment, in particular • Chapter 6: The Ozone Layer in the 21st Century (Greg Bodeker, Darryn Waugh et al.) • IPCC AR4, in particular • Chapter 7: Couplings Between Changes in the Climate System and Biogeochemistry • (Ken Denman, Guy Brasseur et al.)

12. CCMVal Deliverables • Reference simulations defined by CCMVal (transient runs covering past & future) • Forcing data sets made available (e.g. SSTs, GHGs, • halogens) • Model output made available to the wider community • for further analyses • Key results documented in two refereed journal articles • (Eyring et al., 2006, 2007, JGR, Parts 1 & 2) • CCMVal is a core component of the WCRP/IGBP Atmospheric Chemistry and Climate (AC&C) Cross-cutting Activity

13. ODS production ODS production Ozone recovery and climate change Stratospheric Cl and Br Ozone-depleting chlorine and bromine in the stratosphere 2006 Scientific Assessment of Ozone Depletion O3 Global ozone change UV Ultraviolet radiation change 1980 Now~ 2100

14. CCMVal simulations from the REF2 reference run (smoothed) Black is obs Eyring et al. (2007 JGR)

15. It is interesting to compare with how things were for the 2002 Ozone Assessment This is what motivated CCMVal! Austin et al. (2003)

16. SPARC Report on Evaluation of Coupled Chemistry Models The “SPARC Report on Evaluation of Chemistry Climate Models” aims to provide a comprehensive, up-to-date assessment of • The ability of CCMs to represent the stratospheric ozone layer, stratospheric climate and variability, and • The coupled ozone-climate response to natural and anthropogenic forcing. • The report will be completed in time (late 2009) to provide useful and timely information for the 2010 WMO/UNEP O3 and IPCC AR5. It will: • Allow a better overall evaluation of the models • Couple assessments of models with analysis of the science • Improve input of CCM community to the assessments

17. Grading The Report will (hopefully) assign quantitative scores (grades) to the different data-based diagnostic tests. This will: Make it possible to assign relative weights to the prediction by the different models and to form a best estimate that takes into account differing abilities of models to reproduce key processes; Enable a quantitative assessment of improvements made during model development.

18. Skill scores by metric and model Waugh & Eyring, 2008 Based on Eyring et al., 2006 (JGR)

19. Courtesy of A.R. Ravishankara, Phil Rasch and Sarah Doherty

20. Tropical Tropopause Layer (TTL) SPARC/IGAC/GEWEX Links • The role of convection in the TTL: • Follow-on from 2006 SPARC/GEWEX/IGAC workshop, • new Cloud Resolving Model (CRM) case studies on overshooting convection and different microphysical processes in H2O budget, • to be discussed at GEWEX Pan-GCSS workshop • Supersaturation workshop (Karlsruhe, June, 2007) • Topics: RHI in the TTL, instrumental issues • AquaVIT, AIDA hygrometer intercomparison campaign, 3 weeks • in October 2007, double-blind experiments, international referees • AquaVIT workshop in Zurich in May 2008 • WAVAS II - Updated Assessment of Tropospheric and Stratospheric Water Vapour •  A new WCRP/SPARC report or review paper

21. Supersaturation workshop (Karlsruhe, June, 2007) Topics: RHI in the TTL, instrumental issues

22. Rejuvenated SPARC Gravity-Wave Activity CCMs consistently show a strengthening of the Brewer-Dobson circulation as a result of climate change A major component of the trend (in this case, 60%) appears to be from orographic gravity-wave drag Total wave drag Resolved wave drag Parameterized OGWD Courtesy Charles McLandress, University of Toronto

23. SPARC Study on The Role of Halogens in Ozone Depletion From Marc von Hobe, Science 2007 • Workshop in summer 2008. • White paper and a peer-reviewed paper planned. • Time line: deliverables 12-18 months (completion is critical for the UNEP/WMO ozone assessment in 2010)

24. Lessons from IPCC • AR4 had an unprecedented level of “SPARC-friendly” authorship • Discrepancy between what the report says in terms of understanding and what is in models: • we need to show modelling groups why stratosphere is relevant if they are going to commit resources • need to provide information in user friendly way for IPCC report (calculate forcings, give advice on model resolution) • Some key gaps: • - stratospheric ozone not updated since the IPCC TAR • - stratospheric water vapour remains a key uncertainty • solar effects on chemistry not evaluated • relate stratosphere to regional surface changes outside Antarctica

25. THE GEOENGINEERING DILEMMA An issue for the WCRP? Crutzen Proposal - Should SPARC speak? • Should we proceed as we would on any other scientific problem, at least for theoretical and modeling studies? • Pros: • This is happening in SPARC’s backyard, we have the knowledge, we • should influence the outcome, we should help with doing it “right”, we are in the best position for influencing politicians to take the best measures for avoiding/starting geoengineering solutions. • Cons: • It is scientifically not feasible, it distracts from the actual problem • (reducing GHGs), it channels the resources into the wrong direction, it • gives the wrong sign to politicians, it has unbearable political/social/ • legal consequences (winners/losers), it can’t be done “right” anyway.

26. What should WCRP do (if anything)? • Studies on this topic are already happening, but the focus is generally not on the stratospheric impact • SPARC’s own capacity is limited • CCMVal has its hands full with the SPARC Report • Requires use of coupled models • Options for WCRP • Don’t touch it • However both WMO/UNEP and IPCC will be obliged to assess this work • Wait until there is a body of work to assess • Define experimental protocols so that groups perform their studies in a way that can be meaningfully compared

27. A final thought: What is with the poles? • A major open issue for SPARC: climate change in the polar stratosphere • Models show no convergence • Sensitivity to model details • Strong low-frequency variability makes detection of trends a challenge • Yet polar regions are where we expect the strongest coupling between ozone depletion/recovery and climate change (also between troposphere and stratosphere) • Polar science cuts across many aspects of both WCRP and IGBP; it needs a long-term home (not just IPY)

28. Challenges for SPARC • SPARC IPO funding from CFCAS ends in 2010 with no current prospect for renewal • Long-term “homes” for SPARC science? • New scientific issues continue to arise • Bologna, Italy, 31 August–5 September, 2008 Coordinated with IGAC Conf. the following week in France € 141,700 in financial requests for SPARC GA Thanks for your attention!

29. Stratospheric Processes and their Role in Climate (SPARC) Thank you! SPARC Themes

30. The Fourth SPARC General Assembly • Bologna, Italy, 31 August–5 September, 2008 • Coordinated with IGAC Conf. the following week in France • Major topics • - stratosphere-troposphere dynamical coupling • - stratospheric variability and climate change • - extra-tropical upper troposphere/lower stratosphere • - detection, attribution and prediction of stratospheric change • - tropical tropopause layer (TTL) • - atmospheric chemistry and climate • - stratospheric data assimilation • - gravity-wave processes and their parameterization • - stratospheric and upper tropospheric water vapour • Conference site: http://www.cmcc.it/sparc-ga2008

31. SPARC IPO • The SPARC IPO is supported jointly by • The Canadian Foundation for Climate and Atmospheric Sciences • - Major funding support committed to December 31, 2010 • - Subsidiary funding for SPARC-IPY Coordinator • 2. The Canadian Space Agency • - Current funding grant ended on March 31, 2008 • but renewal expected • 3. Environment Canada • - Ongoing in-kind support • 4. The University of Toronto • - Ongoing in-kind support

32. Themes of the SPARC Programme • Climate-Chemistry Interactions • Detection, Attribution, and Prediction of Stratospheric Change • Stratosphere-Troposphere Dynamical Coupling • Ongoing activities within these themes include • - Stratospheric Temperature Trends Working Group • - Data Assimilation Working Group (SPARC-DAWG) • - Solar Influence Activity (SOLARIS) • - SPARC-IPY (closely coupled with SPARC-DAWG • activities) • - CCMVal (and associated AC&C activities)

33. Ted Shepherd’s straw proposal for possible future WCRP projects • Long-term climate change (joint with IGBP) – input into mitigation needs • (Multi-)decadal predictability – input into impacts needs • Regional climate downscaling – direct input to users • Improving the models (joint with WWRP) – “connecting climate physics to climate modelling” (P. Morel) • Air quality and biosphere impacts (joint with IGBP)