CLIVARGODAE Synthesis Evaluation Meeting

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CLIVAR/GODAE Synthesis Evaluation Meeting

• ECMWF
• Aug.31/Sept. 1, 2006

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CLIVARs Synthesis Needs

• Develop an improved data base and reference data
  sets for climate research.
• Describe the state of the time-varying global
  ocean over the past several decades.
• Quantify the interaction of the ocean with the
  atmosphere.
• Deliver improved boundary conditions for
  regional/basin scale modeling and assimilation
  efforts.
• Facilitate the initialization of coupled models
  for studies and prediction of seasonal-to-decadal
  variability as a step toward coupled data
  assimilation.
• Provide guidance on the effectiveness of the
  ocean observing system for monitoring climate
  variability and climate change.

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Challenges

• This spectrum of applications of ocean synthesis
  for climate variability and prediction purposes
  spans over seasonal-to-interannual,
  decadal-to-centennial, and even millennial time
  scales.
• These applications pose a range of accuracy and
  robustness requirements on ocean reanalyses.
  Consequently, they necessitate somewhat different
  data assimilation approaches and evaluation.

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Ongoing Synthesis

• Several global ocean data assimilation products
  are available today that in principle can be used
  for climate applications.
• Underlying assimilation schemes range from simple
  and computationally efficient (e.g., optimal
  interpolation) to sophisticated and
  computationally intensive (e.g., adjoint and
  Kalman filter-smoother).
• Intrinsically those efforts can be summarized as
  having three different goals, namely
• climate-quality hintcasts,
• high-resolution nowcasts, and
• the best initialization of forecast models.

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Synthesis Evaluation Effort

• Is needed to determine the quality of existing
  global ocean analysis/synthesis products and to
  assess their usefulness for climate research.
• Is needed to make recommendations for resource
  allocations in the future.
• Should be oriented along global science
  questions.
• Should focus on global results and their
  usefulness for climate research purposes,
  globally and for basins.
• Needs to be done in a close collaboration with
  CLIVAR's basin panels to their serve
  implementation, e.g., ongoing and planned
  regional process experiments.
• Should include process modeling and IPCC
  communities.

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GSOP/GODAE Synthesis Evaluation Workshop,
Aug.31,Sept. 1, 2006 at ECMWF.

• The overall goals of the inter-comparison of
  global synthesis efforts are to
• (Begin to) Evaluate the quality and skill of
  available global synthesis products and determine
  their usefulness for CLIVAR.
• (Begin to) Identify the common strength and
  weakness of these systems and the differences
  among them, as well as to identify what
  application can be best served by what synthesis
  approach.
• Define and test climate-relevant indices that in
  the future should be provided routinely by
  ongoing or planned synthesis efforts in support
  CLIVAR and of the wider community.
• Define climate data sets and standards required
  for CLIVAR syntheses.

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Global Science Questions

• 1) THE OCEANS IN THE PLANETARY HEAT BALANCE
• heat storage,
• heat transports and
• ocean/atmosphere feedbacks.
• 2) THE GLOBAL HYDROLOGICAL CYCLE
• water balance,
• rainfall variability
• salinity and convection.
• 3) SEA LEVEL
• sea level rise
• sea level variability.

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Reference Data Sets

• CLIVAR is engaged in the WCRP-wide climate data
  sets reprocessing effort.
• In the context of CLIVAR's synthesis, CLIVAR
  reference data sets and there error fields are
  required for (1) the analysis of climate
  processes (2) for the evaluation of assimilation
  and WGOMD simulations and (3) as data constraints
  input to global synthesis.
• CLIVAR reference data sets include in situ and
  satellite data sets, as well as surface flux
  reference data sets, among others.

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CLIVAR Reference Data Sets

• Beyond CLIVAR's own needs, climate reference
  datasets are also required to meet wider needs
  for climate information (GCOS Implementation
  Plan).
• In particular the GCOS IP identifies the need for
  analysed products for all Essential Climate
  Variables (ECVs).
• Given CLIVARs responsibilities for the role of
  the oceans in climate within WCRP, one of
  CLIVARs primary (but indeed not sole) concerns
  lies in the area of reference datasets for the
  ocean ECVs and those related to air-sea exchange.
  
• We need to help defining essential climate
  variable (ECVs) and to define CLIVARs effort in
  climate data reprocessing (insitu and satellite).

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Other Reference Data Sets

• Examples include
• SST Fields Reynolds or Pathfinder SST, GHRSST-PP
  SST Reanalysis
• SSH Fields TOPEX/Poseidon and JASON-1 sea level
  anomaly from AVISO or PO-DAAC
• Time-mean sea surface topography synthesized from
  drifter data and T/P data (Niiler) and GRACE
  data.
• De-tided tide-gauge data at selected stations
  with IB correction applied.
• Selected WOCE lines and corresponding times P01
  (50º N), P03 (25º N), P04 (10º N), P06 (30º S),
  P14 (dateline). A05 (25º N), A16N (20º W). I03
  (20º S), I08N (80º E). TOGA-TAO, BATS, HOT, and
  Station P time series.
• Levitus climatological of temperature and
  salinity.
• Velocity Fields Surface drifter (Niiler), 900-m
  float (Davis) velocities ADCP data.
• Surface Flux fields as defined by white paper of
  Josey and Smith (2006).

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Charge to Meeting

• Begin a quantitative evaluation of synthesis
  results with respect to their skill and
  usefulness for CLIVAR.
• Identify strength and weakness of systems and
  explain differences among them.
• Define pilot set of climate-indices and
  diagnostic quantities to be produced on a regular
  basis as prototype synthesis support of global
  and regional CLIVAR research.
• Define data set required as input and identify
  present gabs.
• Discus modeling standards for ocean synthesis.
• Discus forcing standards for ocean synthesis.

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Outcome

• Quantitative statement of the skill of available
  global synthesis products and their usefulness
  for CLIVAR.
• Identification of common strength and weakness of
  systems and the differences among them.
• Prototype synthesis support of global and
  regional CLIVAR research (will be extended as
  work progresses).
• Basis set of recommendations with regard to
  future synthesis resource planning.
• Recommendations for CLIVAR data processing and
  management.
• GSOP Web site to present climate indices from
  ocean syntheses over last 50 years (counter part
  to OOPC indices from data alone).
• Stimulation for WGOMD and IPCC to join in.

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Agenda (1)

• THURSDAY, AUGUST, 31
• 830 Goal of Synthesis Evaluation Effort and
  Charge to the meeting (D. Stammer)
• 845 CLIVAR Data Sets (David Legler)
• 915 CLIVAR Surface Flux Reference Data (Simon
  Josey)
• 945 Discussion of Data and Error Requirements
  (Carl Wunsch)
• 1015 Coffee Break
• SUMMARY of individual Synthesis Projects (10 min.
  each hand outs)
• 1200 Lunch Break
• 1410 Ocean Indices from Data (OOPC, Albert
  Fischer)
• 1430 CLIVAR/GODAE Metrics for Ocean Analysis
  (Detlef Stammer)
• 1450 Data archiving/DODS (Peter Hacker and Paco
  Doblas-Reyes) (10 min. each)
• 1500 Coffee Break
• 1530 Group RMS Model-Data misfits (P. Heimbach,
  D. Menemenlis)
• 1630 Group Meridional Transports (A. Köhl)
• 1730 General Discussion
• 1800 Adjourn

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Agenda (2)

• FRIDAY, SEPTEMBER, 1
• 830 Group Surface Fluxes (L. Yu)
• 930 Group Changes in Sea Level, Heat and Salt
  Content (Magdalena Alonso-Balmaseda and
  Anthony Weaver)
• 1030 Coffee Break
• 1100 Group Transports through key regions (T.
  Lee)
• 1200 Lunch Break
• 1300 Group Water Masses (K. Haines and T. Lee)
• 1400 Group Indices (A. Fischer)
• 1500 Coffee Break
• 1530 Carbon Program and Synthesis (D. Wallace)
• 1550 General Discussion
• 1630 Summary and Next Steps
• 1700 END OF MEETING

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• Thank You!