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

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

World Climate Research Programme (WCRP)

CLIVAR 1995 GEWEX 1988 SPARC 1992 CliC 2000 WGNE WGCM

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

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 SPARCs Overall Aim & Modus Operandi

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

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)

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)

Structure of the SPARC Programme

Over the past 3 years CCMVal has engaged 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.) CCMVal Activity

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

1980 Now ~ 2100 ODS production Ozone-depleting chlorine and bromine in the stratosphere Global ozone change Ultraviolet radiation change Ozone recovery and climate change 2006 Scientific Assessment of Ozone Depletion ODS production Stratospheric Cl and Br O 3 UV

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

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

Ozone depletion Ozone recovery O3O3 T u 3-month overlapping SAM-index change Ozone recovery will change the sign of the trend in the Southern Annular Mode Perlwitz et al. (2008 GRL)

CCMVal workshop 2007 University of Leeds, Leeds, UK June 25-29, 2007 Workshop Goals: – Encourage discussion of new observations and methods that can be used to evaluate CCMs – Discuss progress in the evaluation of current CCMs – Coordinate the planned SPARC Report on evaluation of CCMs – Discuss and suggest a strategy for CCM simulations for the next round of WMO Ozone and IPCC Climate Assessments Science Sessions (Talk and Posters) and Breakout Groups: Group I: New CCMVal Ref. and Sensitivity Simulations in Support of O 3 / Climate Assessments Group II: CCMVal Diagnostic Tools, Data Archiving and Data Formats Group III: Define a Strategy for Developing Standards for CCMVal Performance Group IV: SPARC CCMVal Report (in plenary)

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 (1)The ability of CCMs to represent the stratospheric ozone layer, stratospheric climate and variability, and (2)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 O 3 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

Grading The Report will (hopefully) assign quantitative scores (grades) to the different data-based diagnostic tests. This will: 1.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; 2.Enable a quantitative assessment of improvements made during model development.

Projections of Stratospheric Ozone Waugh & Eyring, 2008 Large spread in simulated Cl y CCMs with larger peak Cl y tend to have a later recovery to 1980 value Eyring et al., JGR, 2007 Estimated means and uncertainties weighting models equally (red) or according to their skill (blue)

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

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

DynVar will utilize a range of modelling approaches to address a number of issues: Stratospheric Representation in Climate Models Impact of the Stratosphere on Climate Variability Impact of the Stratosphere on Climate Change The SPARC Dynamics and Variability (DynVar) Activity

DynVar Characteristics Focus on how GCMs stratospheric representation affects tropospheric climate, variability, and climate responses. Distinctive aspects from other SPARC activities: 1.Stronger emphasis on tropospheric aspects. 2.Comparison of high-top and low-top models. 3.Investigation of ocean-atmosphere coupling. 4.Requirement that participating GCMs satisfy basic specs. 5.Focus on processes that do not hinge on coupled chemistry feedbacks or solar influences. 6.Inclusion of a significant theoretical component. First DynVar Planning Workshop: University of Toronto, March 27-28, 2008

DJF sea-level pressure response to 2xCO 2 –Primary sensitivity is to orographic gravity-wave drag, which affects planetary-wave drag at high latitudes –Robust dynamical response to climate change is difficult to identify in the wintertime Arctic stratosphere High-top model Low-top (IPCC) model Sigmond, Scinocca & Kushner (GRL, submitted)

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 H 2 O 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 Tropical Tropopause Layer (TTL) SPARC/IGAC/GEWEX Links

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

Courtesy Charles McLandress, University of Toronto Parameterized OGWD Resolved wave drag Total wave drag 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

A TTL paradigm has emerged and remains an active research area In the extratropics: new observations and measurement campaigns, but no significant convergence of ideas Steps toward development of a broader Tropopause Activity include -A summary article (SPARC Newsletter No. 29) -A web site ( -UTLS session at the Fall 2007 AGU meeting, and TTL and Extratropical UTLS sessions at the Spring 2008 EGU meeting The SPARC Tropopause Initiative

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

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

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 SPARCs 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 cant be done right anyway.

Studies on this topic are already happening, but the focus is generally not on the stratospheric impact SPARCs own capacity is limited –CCMVal has its hands full with the SPARC Report –Requires use of coupled models Options for WCRP –Dont 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 What should WCRP do (if anything)?

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) A final thought: What is with the poles?

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 Challenges for SPARC Thanks for your attention!

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

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:

SPARC IPO The SPARC IPO is supported jointly by 1.The Canadian Foundation for Climate and Atmospheric Sciences - Major funding support committed to December 31, 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

Climate-Chemistry Interactions Detection, Attribution, and Prediction of Stratospheric ChangeDetection, 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) Themes of the SPARC Programme

Ted Shepherds 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)