Transcript (SPARC) (Thomas Peter, ETH Zurich)

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
World Climate Research
Programme (WCRP)
Objectives


Study climate system, determine its
variability and predictability
Determine human influence on climate
World Climate Research
Programme (WCRP)
CLIVAR 1995 
SPARC 1992
WGNE
WGCM
GEWEX 1988 
CliC 2000 
CLIVAR 1995 
SPARC 1992
Atmospheric
Chemistry and
Climate
(AC&C)
WGNE
WGCM
CliC 2000 
GEWEX 1988 
SOLAS
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 welldefined strategic plan for evolution
• 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
CCMVal Activity
http://www.pa.op.dlr.de/CCMVal/
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 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
ODS
production
Ozone-depleting
chlorine and bromine
in the stratosphere
ODS
production
Ozone
recovery
and climate
change
Stratospheric
Cl and Br
2006 Scientific
Assessment of
Ozone Depletion
Global ozone
change
O3
Ultraviolet radiation
change
UV
1980
Now
~ 2100
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)
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 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
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.
Skill scores by metric
and model
Waugh &
Eyring, 2008
Based on
Eyring et al.,
2006 (JGR)
Courtesy of A.R. Ravishankara, Phil Rasch and Sarah Doherty
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
Supersaturation workshop
(Karlsruhe, June, 2007)
Topics: RHI in the TTL,
instrumental issues
Rejuvenated SPARC Gravity-Wave Activity
CCMs consistently show a strengthening of the BrewerDobson 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
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)
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 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.
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
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)
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!
Stratospheric Processes
and their Role in Climate
(SPARC)
Thank you!
SPARC Themes
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
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, 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
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)
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)