SPARC DynVar Status Plans Paul Kushner University of Toronto

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					SPARC DynVar Status & Plans
           Paul Kushner
        University of Toronto
                Background



•   The SPARC DynVar project was initiated at
    the 2006 SPARC SSG meeting.
•   The project’s broad aim is to understand
    the role of the stratosphere in tropospheric
    climate, using GCMs as the principal tools.
•   The project is described in a planning paper
    in the SPARC Newsletter, July 2007.
•   This is the DynVar project’s organizing group. I’ve
    highlighted the names of the project’s coordinators.
                    Project Aims


•   We ask how GCMs’ stratospheric representation
    affects tropospheric climate, variability, and climate
    responses (high-top vs. low-top).
•   We focus on circulation & dynamics
    (complementing CCMVal and SOLARIS)
•   We center on comprehensive GCMs, but include
    a component on theory and simplified models.
•   We want to document the costs and benefits of
    including a realistic stratosphere in an Earth
    Systems Model.
     Analysis Areas & their Coordinators
The project is roughly divided into 4 analysis areas:
A. DynVar Top (Giorgetta, Sassi): Effect of model
stratospheric representation on the circulation and
variability of the climate system.
B. DynVar Intraseasonal (Perlwitz): Intraseasonal strat-
trop coupling, with a view to seasonal prediction.
C. DynVar Climate Change (Manzini): Stratospheric
control of response to climate forcings.
D. DynVar Ideal (Polvani): Cross-cutting theme, analysis
of stratospheric influence using theoretical and
simple-modelling approaches.
                   Simulations

•   We want to set out coordinated experiments and
    analyses. Interested modeling groups include
    CCCma (Canada), NCAR, GFDL, UKMO, MPI.
•   We want to elucidate the role of the stratosphere
    for various degrees of coupling to the land-ocean
    surface:

    •   Prescribed SST AGCM, Mixed-layer ocean/
        AGCM, Dynamical ocean/AGCM,
    •   Forced with standard climate forcings.
•   Theoretical component: explain the GCM results
    with simple models and theory.
           Overview of Activities
•   Our main activies for this year:

    •   September 2007 Santorini Chapman
        Conference.

    •   March 2008 planning workshop.

    •   Participation in Ozone Forcing Dataset
        workshop in Bologna September 2008.

•   Main activities for coming year:

    •   Setup of DynVar server

    •   Publication of plan

    •   Starting coordinated runs.
Emerging Research Results Relevant to DynVar



•   There were several papers over the last year
    (Santorini, March DynVar Workshop, Bologna)
    that were connected in one way or another to
    DynVar themes.

•   Most directly relevant to DynVar were papers
    that emphasized a systematic comparison
    between high top and low top models.

•   This is an area where I think the project can
    make progress in the short term.
Hi-Top/Low-Top Intercomparison: ECHAM Models

      Hi Top Minus Low Top: Temperature
               (OAGCM)                    (AMIP)




          Hi Top Minus Low Top: w*
                            (OAGCM)




                                      Giorgetta et al.
      Circulation Response to Global Warming
                                                     U         SLP
The Hi-Top Canadian GCM (CMAM)
gets a tropospheric NAM response to     CMAM
2XCO2.                                  Hi-Top
                                      10-3 hPa Lid
The Low-Top Canadian GCM
(Standard) does not.                   Standard
                                       Low-Top
But a Low-Top version of CMAM also     3 hPa Lid
gets the NAM response.

Orographic GWD (OGWD) settings          CMAM
turn out to control the response.      Low-Top
                                      10 hPa Lid


                                       Standard
                                       Low-Top,
                                        CMAM
                                       OGWD
                                                          Sigmond et al. 2008
       Circulation Response to Global Warming
                                                     U        SLP
If the CMAM GWD settings are put in
the Standard GCM, it gets a NAM         CMAM
response too.                           Hi-Top
                                      10-3 hPa Lid
The OGWD controls lower
stratospheric winds; stratospheric     Standard
resolution is secondary here.          Low-Top
                                       3 hPa Lid


                                        CMAM
                                       Low-Top
                                      10 hPa Lid


                                       Standard
                                       Low-Top,
                                        CMAM
                                       OGWD
                                                          Sigmond et al. 2008
 Control of Tropospheric Response to Stratospheric Cooling

Hi-Top and Low-Top CMAM get a                              U               SLP
tropospheric SAM+ response to
Antarctic stratospheric cooling.       CMAM
                                       Hi-Top
But non-orographic GWD can
control the response.
                                       CMAM
The bottom row shows the impact       Low-Top
of using a non-conservative
boundary condition on the GWD.
                                        CMAM
Low-top models might represent        Low-Top;
SAM sensitivity accurately, but you   Flux GWs
have to be careful with               to Space!
implementation details.
                                                  Shaw, Sigmond, Shepherd & Scinocca 2008
         ENSO Teleconnections
Hi Top         Low Top          Obs




                         Cagnazzo & Manzini
       DynVar Planning Workshop

•   The workshop aimed to plan DynVar activities for
    the coming 2-3 years.

•   It consisted of a day of presentations and
    discussions on the project’s research themes, and a
    second day of working meetings on project plans.

•   The workshop was open to all DynVar organizers
    and participants, and the DynVar project itself is
    open to all interested researchers.

•   The workshop was held in conjunction with the
    GWD Initiative workshop. We met in plenary for
    part of the meeting, to coordinate on diagnostics.
           DynVar Planning Workshop
Aims of the planning component of the workshop:

•   Summarize the science goals of DynVar and Analysis
    Area subprojects. (Completed)

•   Specify in detail which simulations will be run for the
    intercomparison (multiple high top and low top
    models). (Partially completed.)

•   Specify in detail the diagnostic requirements for the
    subprojects. (Partially completed.)

•   Outline a data access policy and distribution approach
    for model output. (Completed.)

•   Tentatively outline a plan for dissemination of the
    results. (Not started --- too soon.)
       DynVar Planning Workshop




•   To prepare for the planning meeting, we
    distributed a survey to gauge interest,
    projects, potential contributions from
    modelling centres.
•   The survey results provide input into the
    diagnostic requirements for the project.
Lecture by Alan Plumb
Thanks SPARC IPO!
    Science Content of the Workshop


•   We attracted some new people from
    outside the “usual suspects”. E.g.
    participants like David Straus from COLA/
    IGES.
•   The idea to meet jointly with the GWD
    workshop was successful overall.
    •   Appropriate diagnostics identified from
        global GCMs to be used by the GWD
        project.
              Planning Session


•   D. Waugh: overview of CCMVal plans & data
    policy.
•   F. Sassi: outline of DynVar simulations. The
    real question is who wants to commit to
    these runs?
•   J. Perlwitz: outline of survey results. Looks
    like about 20 or so research projects could
    use the data.
•   P. Kushner: Data policy.
           Data Policy and Server

•   DynVar will follow the CCMVal two-phase data
    policy and data formats (netcdf/CFMIP).

•   Data contributed to the projected will be
    served from the server dynvar that is being
    installed at U of T this month:

    •   Server with 4TB of backed up storage.

    •   Users will log in and will be able to
        preprocess the data before downloading
        (standard utilities installed)

    •   Cost of about CDN$10K on NSERC funds.
                Simulations

•   Basic starting points for prescribed SST
    runs is CCMVal Ref 1 (prescribed radiative
    forcings).
•   CCMVal runs have occupied the groups
    fully this year. A clear commitment for any
    groups to do runs specifically for DynVar
    has not been actively solicited or provided.
•   An unresolved question is how to treat
    ozone forcing in such runs. Let’s focus on
    this issue.
               AM Signatures: Ozone Depletion
                  Trend,         Projection of   GCM Response to
                1968-1998      Trend onto SAM    Ozone Depletion



   Z500




   Surface
  winds and
temperatures


                                           Thompson & Solomon 2002,
                                            Gillett and Thompson 2003

     • Southern Hemisphere trends are strongly SAM related.
     • Photochemical ozone loss and recovery control a lot
          of this (see Son et al., Perlwitz et al.).
     Prescribed Ozone Forcing Runs
•   For DynVar models to test the effects of stratospheric
    resolution on the response to ozone forcing, we want
    to force a variety of AGCMs with a prescribed ozone
    forcing dataset.

•   At the time of the March workshop, we were pointed
    to the Bodeker et al. effort to establish an ozone forcing
    dataset.

•   PJK attended the ozone dataset workshop in Bologna
    and has proposed that DynVar become an early user of
    the dataset.

•   One idea would be to run tests on the new dataset that
    would look at the basic response to the 1970-2000
    period of photochemical ozone loss, as in Gillett and
    Thompson.
              Status/Discussion

•   We have been busy, but PJK was not able to sustain
    the pace of DynVar past March 2008. PJK’s
    research group had major technical problems over
    the summer from which we are still recovering.

•   DynVar server should be up and running soon, and
    we can upload some data on it.

•   Revised project plan will be submitted to
    Newsletter (ok Diane?)

•   We have proposed to hold a follow on workshop
    for April 27-28 2009 in Hamburg. Marco Giorgetta
    will host. SPARC IPO support is now requested.
            Status/Discussion

•   We need to development a firm
    commitment from modelling groups to do
    some runs. But it seems unrealistic to get
    such a commitment right now with CCMVal
    being an overwhelming priority for many
    groups.
•   Need a clearer path forward for ozone
    forcing.
•   Should groups coordinate on coupled
    ocean/high-top atmosphere model testing?

				
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