Decadal Prediction XCut

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Decadal Prediction X-Cut

• Jochem Marotzke
• Max Planck Institute for Meteorology (MPI-M)
• Howard Cattle
• ICPO, CLIVAR, NOCS

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Outline

• Basic Rationale for Decadal Prediction as X-Cut
• Current status of WCRP decadal prediction
  activities
• Ad-hoc Joint Working Group
• CLIVAR Panels
• Policy Relevance
• Organization and Governance of WCRP

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Basic Rationale for Decadal Prediction as X-Cut

• Objectives of WCRP
• 1. to determine the predictability of climate,
  and
• 2. to determine the effect of human activities on
  climate
• Both objectives meet in decadal prediction
  anthropogenic climate change and natural
  variability expected to be equally important
• Meeting ground weather climate communities
  (seamlessness, WCRP Strategic Framework)
• Data assimilation initialization (weather, S-I)
  cryosphere, biogeochemistry (centennial)

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Current status WCRP decadal prediction activities

• WCRP CLIVAR WGCM WGSIP ad-hoc group (Tim
  Stockdale Gabi Hegerl (lead), Tim Palmer, )
• Assess skill of decadal predictions
• Objective 1 Short-term prediction of climate for
  the next 30 years to 2030 or 2035
• Objective 2 Developing the science of
  multi-decadal prediction in the context of a
  changing climate
• Part of (?) motivation arose from preparations
  for AR5 (Aspen 2006), calling for shorter (30-yr)
  hi-res simulations, in addition to centennial
  runs
• Aspen 2006 needed elaboration Keep runs short
  to save computer time only works if you know how
  to initialize (cf., climate drift)
• Working Group tackles initialization
  uncertainties of decadal prediction head-on

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Current status WCRP decadal prediction activities

• CLIVAR Panels
• Global Synthesis Observations Panel (GSOP)
• Ocean initialization (N.B. ocean so far the only
  focus)
• Comparison of existing ocean synthesis products
• Atlantic Implementation Panel (AIP)
• Most decadal prediction efforts so far under AIP
  remit
• Funding commitment in Europe (e.g., funded
  RAPID-WATCH, including Atlantic MOC decadal
  predictability EU FP7 IP THOR submitted FP7 IP
  COMBINE to-be-launched German research program
  on decadal predictability)
• US Funding commitment pending (AMOC)

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Current status WCRP decadal prediction activities

• CLIVAR Panels
• Pacific Panel Assessed decadal predictability of
  the 2nd kind arising from changing GHG aerosol
  concentrations signal-to-noise from AR4 runs
• Indian Ocean Panel No activities yet on decadal
  predictability and prediction

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First Decadal Climate Prediction
D. M. Smith et al., Science 10 August 2007
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Decadal climate prediction North Atlantic SST
Annual
Assimilation HadISST Hindcasts Free model
Pentadal
Decadal
Pohlmann et al. (2008)
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MOC at 25?N in ocean syntheses (GSOP)
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First observed MOC time series, 26.5?N Atlantic
Florida Current
MOC
Ekman
Upper mid-ocean
S. A. Cunningham et al., Science (17 August
2007)
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Modelled vs. observed MOC variability at 26.5?N
Correlation
RMS variability

• Observations
• ECCO (Ocean Synthesis)
• ECHAM5/MPI-OM

Baehr et al. (2008)
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Policy relevance

• Long-term planning in industry, business
  public sector overwhelmingly occurs on the
  decadal timescale
• Adaptation planning to climate change
  overwhelmingly occurs on the decadal timescale
• Clear that, in addition to the multi-decadal
  mitigation planning very-long term perspective,
  decadal timescale is crucial

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Organization and Governance of WCRP

• Decadal prediction is a vibrant effort if one
  considers the focus on
• CLIVAR science
• Ocean initialization
• Atlantic
• We need to develop broader scope concerning
• Areas other than the Atlantic
• Roles in initialization of
• Soil moisture (GEWEX)
• Cryosphere (CliC)
• Stratosphere (SPARC)
• The science of coupled data assimilation
  initialization has not been developed yet
  WCRP-wide effort needed

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• Thank you for your attention