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CLIVAR/GODAE Synthesis Evaluation

CLIVAR/GODAE Synthesis Evaluation. 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.

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CLIVAR/GODAE Synthesis Evaluation

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  1. CLIVAR/GODAE Synthesis Evaluation

  2. 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.

  3. The overall goals of the inter-comparison of global synthesis efforts are to: Evaluate the quality and skill of available global synthesis products and determine their usefulness for CLIVAR. 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 standards required for CLIVAR syntheses. Synthesis Evaluation

  4. 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.

  5. Expected 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.

  6. Metrics:How do we measure goodnessin the synthesis evaluation??

  7. Metrics Systematic model-data comparison: RMS model data differences rel. to prior data errors. Comparison to reference data sets, e.g., surface fluxes. Comparison with time series stations. Computation of integral quantities. Budgets, e.g., heat content and its change. Model-Model differences (incl. first guess).

  8. Intercomparison Quantities: 1. RMS Model-Data Misfits: (Discussion Lead: Patrick Heimbach) Difference from WOA01 climatological (monthly, Jan.-Dec.) potential T & S RMS misfit from Reynolds SST RMS misfit from in-situ T & S profiles (including XBT, CTD, Argo, moorings) RMS misfit from altimeter-derived SSH RMS misfit from tide-gauge SSH 2. Meridional Transports: (Discussion Lead: Armin Koehl) Timeseries of meridional MOC of the global ocean, Atlantic and Indo-Pacific as a function of latitude and depth and for the global ocean as a function of latitude and potential density. Timeseries of meridional heat and freshwater transports of the global ocean, Atlantic, and Indo-Pacific as a function of latitude. Time series of maximum MOC strength and heat transport at 25N, 48N in North Atlantic

  9. Intercomparison Quantities: 3. Change in Sea Level, Heat and Salt Content (Discussion Leads: Magdalena Alonso Balmaseda; Anthony Weaver) Monthly means of averaged temperature (proxy to heat content) and salinty over the upper 300m/750m and 3000m. Time series for spatial averages within a list of 30 pre-defined boxes in various parts of the ocean. Monthly means of sea level, and optionally steric height and/or bottom pressure. Time series for spatial averages within a list of 30 pre-defined boxes in various parts of the ocean. 4. Transports through Key Regions: (Dsicussion Lead: Tong Lee) Indonesian throughflow volume transport ACC volume transport through the Drake passage. Florida Strait volume transport, temperature flux, and salinity flux.

  10. Intercomparison Quantities: 6. Water Masses: (Discussion Lead: Keith Haines and Tong Lee) 18-C water volume in the N Atlantic Ocean, volumne-weighted average salinity of the 18C water as a function of month. Annual Maximum mixed layer depth within the Labrador sea and the T,S properties of that mixed layer. Warm-water volume in the equatorial Pacific (5S-5N, 120E-80W) AND tropical Pacific (20S-20N, 120E-80W), Depth of 20 degree isotherm in Pacific Ocean as a function of longitude, latitude, and month. 7. Indices: (Discussion Lead: Albert Fischer) Sea surface temperature anomaly indices averaged over lat-lon boxes in the ocean. Here are the indices: Pacific: Nino1+2; Nino3; Nino3.4; Nino4 Indian: SETIO; WTIO N. Atlantic: Curry and McCartney transport index.

  11. Intercomparison Quantities: 8. Surface Fluxes: (Discussion Lead: Lisan Yu) Monthly means of net surface heat and freshwater flux as function of geographic location. Time mean of net surface heat flux and freshwater flux over entire model domain. Zonal averages of annual mean net surface heat flux and freshwater flux over the model domain.

  12. Synthesis Evaluation Individual synthesis efforts were ask to compute indices from their results prior to the workshop and make them available to the project for further evaluation. Input has been solicited from individual basin panels regarding metrics and indices for global reanalyses and the identification of CLIVAR reference data sets. The evaluation effort will be based on results available from the period 1950 to present, including those that cover the TOPEX/JASON-1 era.

  13. Feedback from Indian Ocean Panel • As extra indices: Intercomparison for the Indian-Ocean heat content, IOD index, and ITF, Wyrtki jet in the equatorial Indian Ocean, Agulhas outflow and related heat and freshwater transports. • One issue for using the products in the Indian Ocean: intraseasonal variability is a key element for the IOP and AAMP, requires to archive the fields at finer intervals (say 3-day averages).

  14. RTS smoother 3D-VAR Some details about legends

  15. Comparison to WOA01 climatology (Forget, Heimbach, and Menemenlis) (A) Maps of mean over seasonal cycle (ia) T, S: lon/lat maps of vertical mean 0 to 750m (ib) T, S: R.M.S. vs. lat. of zonal mean, and vertical mean 0 to 750m (iia) as (ia), but vertical mean 750 to 3250 m (iib) as (ib), but vertical mean 750 to 3250 m (B) Seasonal cycle over top 100m (i) Hovmueller-type diagram of lat-vs-month (0 to 100m) (ii) Time series for following latitudinal band -70 to -50 (ACC); -50 to -30 (SH mid-lat); -30 to -10 (SH sub-tropics) -10 to 10 (tropics); 30 to 30 (NH sub-tropics); 30 to 50 (NH mid-lat) 50 to 70 (NH sub-polar)

  16. Transport Measures Meridional overturning, MOC: MOC on density surfaces: Heat transport (rel. 0oC): Freshwater transport (rel. 35 psu):

  17. Global Heattransport K-7 Ganachaud&Wunsch(1996)

  18. North Atlantic Heattr. ENSEBLES Ganachaud&Wunsch(1996)

  19. Indo-Pac. Heattransport K-7 Ganachaud&Wunsch(1996)

  20. Heat transport 25oN K-7

  21. Heat transport 48oN K-7

  22. Max. MOC 25oN K-7 Bryden et al. (2005) ECMWF

  23. Max. MOC 48oN K-7

  24. Heat/FW transport Global Mean 25N (PW) Global Mean 20S (PW) Ind.-Pac. Mean 25N (PW) Atl. Seasonal 25N (PW) Atl. Drift 25N (PW/10yr) Global Mean FW 30S (Sv) Global Mean FW 25N (Sv) Atl. Mean 25N (PW) Atl. STD 25N (PW) Method Details Model Details Ganachaud& Wunsch (2000) 1.80 -0.80 0.50 1.30 Macdonald (1998) 0.72 -0.3 MIT 1-1/3o, Lev KPP, GM partition Kalman ECCO-JPL 1.45 -1.30 0.44 1.01 0.30 -0.37 0.50 -0.35 ECCO-SIO 1.40 -0.44 0.45 0.96 0.21 0.13 -0.08 0.35 -0.31 MIT 1o, Lev, KPP, GM adjoint ECCO-50yr 1.26 -0.63 0.38 0.88 0.21 0.14 0.034 0.33 -0.31 MIT 1o,Lev, KPP, GM adjoint ECCO-GODAE 1.15 -0.78 0.33 0.82 0.21 0.13 0.033 0.55 -0.31 MIT 1o,Lev adjoint GFDL 1.01 0.22 0.20 0.77 0.31 0.11 -0.018 MOM INGV 2.2 -1.1 0.7 1.45 0.25 0.11 -0.27 0.82 -0.45 OPA 2-1/2o,Lev, TKE, eddy vel multivar. OI SODA 0.99 0.16 -0.08 MOM 1-1/3o Lev KPP,GM OI Heat/FW transport

  25. MOC ENSEBLES l-NADW 92 – 02 3-5km Seasonal MOC 25N (Sv) Mean MOC 48N (Sv) Drift MOC 25N, 92-02 (Sv/10yrs) Min. Ind-Pac MOC(Sv) MOC AABW North-Atl. Max. Atl. MOC (Sv) Mean MOC 25N (Sv) STD MOC 25N (Sv) Method Details Model Details ……….. -4.0 ……… 1.2-2.5 G & W (2000) Bryden et al(2005) 16(<27.72) 19.4-14.8 14(<27.72) ………….. ………. 10.4-6.5 (Yes) too shallow partition Kalman MIT 1-1/3o, Lev KPP, GM ECCO-JPL 19 17 4.0 -7.0 19 No -16 ECCO-SIO (Yes) 1Sv not ov.Eq. (No) 2Sv MIT 1o, Lev, KPP, GM 19 16 3 1.8 -0.7 19 adjoint -11 ECCO-50yr (Yes) not ov.Eq. MIT 1o,Lev, KPP, GM 18 14 3 1.7 0.2 17 adjoint No -8 ECCO-GODAE (Yes) not ov.Eq. (No) 4Sv 17 14 3 1.9 -0.3 17 adjoint -15 MIT 1o,Lev ECMWF (30N) Yes 13Sv 16 2 0.28 -3.1 6Sv OI HOPE 1o,Lev GFDL (No) 7Sv 30 14 3 1.2 -1.5 15 Yes -10 MOM INGV (Yes) only S Atl. multivar. OI Yes 6Sv OPA 2-1/2o,Lev, TKE, eddy vel 25 22 3 1.2 -3.3 18 -15 SODA (Yes) 1Sv no ov. 20S MOM 1-1/3o Lev KPP,GM 22 17 4 1.2 0.6 13 OI No

  26. ECCO-SIO ECCO-SIO/50y + Ref. Bryden et al. (2005)

  27. ECCO-50y ECCO-50y

  28. SODA SODA

  29. Temperature, Salinity and Sea Level:climate variability from ocean reanalyses(Intercomparison Items 3 & 4) Magdalena A. Balmaseda Anthony Weaver

  30. Outline Defining the variability: signal and noise Seasonal cycle removed: Anomalies with respect to the common period (1994-2000) 12-month/3-month running mean Focus on the upper ocean (upper 300m): Equator, Mid latitudes Temperature and salinity: What can we say about climate variability? Time variation of uncertainty Outliers? Source of uncertainty (forcing, model, assimilation method)? Sea Level variations: volume or mass changes? Summary and conclusions

  31. ITF FC ACC ITFt ITFs FCt FCs ACCt ACCs Sv Sv Sv PW PW PW Kg/s Kg/s Kg/s K7 -12.4 157 CRFS-A -12.9 16.6 147 CRFS-2 -13.2 24.2 147 ECCO-50yr -11.0 29.3 129 -1.0 -0.4 2.1 1.1 1.4 4.5 ECCO-SIO -10.7 30.6 154 -0.9 -0.4 2.2 1.1 1.6 5.3 ECMWF -10.6 14.8 148 GFDL -15.7 24.3 171 -1.0 -0.6 1.6 0.8 1.7 6.1 INGV -11.9 24.6 127 2.8 0.9 MOVE-G -23.4 179 ECCO-JPLKF -13.2 27.6 132 -1.2 -0.5 2.3 1.0 1.4 4.6 MCTR 3DVAR -18.7 15.0 142 MCTR KF -12.8 21.8 149 ECCO-GODAE -11.1 26.6 148 -0.9 -0.4 1.9 1.0 1.5 5.1 SODA -14.5 27.5 158 -1.2 -0.5 2.1 1.0 1.7 5.6 Obs. Analysis -10 ~ -15 31.9 120~160 1993-2001 mean transports/fluxes: For Florida Current: black - meridional transport near 26.5N, 80-75W; red – zonal transport between Florida & Cuba.

  32. (all in Sv) ITF FC ACC rms dev. of FC from cable data K7 3.5 7.0 CRFS-A 5.0 4.7 6.4 4.9 CRFS-2 5.2 4.7 6.2 5.3 ECCO-50yr 2.4 1.6 4.1 2.9 ECCO-SIO.it69 2.5 2.2 4.6 3.1 ECMWF 3.0 2.2 4.0 3.0 GFDL 2.5 2.8 5.0 3.6 INGV 3.1 5.6 3.5 5.5 MOVE-G 4.0 6.3 ECCO-JPL RTS smoother 3.0 3.0 4.1 3.4 MCTR 3DVAR 5.5 5.1 6.6 5.3 MCTR KF 3.2 1.4 4.6 2.8 ECCO-GODAE.v2.199 2.6 2.2 4.4 3.3 SODA 4.3 2.6 4.5 5.0 rms diff. among models 2.3 3.0 3.5 Measurement 2.5 1993-2001 rms variability of volume transport, rms difference among models, and rms difference from cable measurements

  33. ITF volume transport (Sv) Total Spinup problem Island Rule doesn’t work? Or effect of geometry/topography? Anomaly relative to 1993-2001 mean Remarkable consistency

  34. ACC salinity flux Total Anomaly relative to 1993-2001 mean

  35. Ocean Water Masses Keith Haines, Greg Smith Environmental Systems Science Centre (ESSC), Reading University

  36. Requested Data Warm-water volume in the equatorial Pacific (5S-5N, 120E-80W) AND tropical Pacific (20S-20N, 120E-80W), = volume of water with T ≥ 20C (excluding Indonesian Seas) based on monthly data Depth of 20C isotherm, 2S-2N average, as a function of longitude and time in Pacific (No results on this yet) Annual means of 17.5-18.5-C water volume in the N Atlantic Ocean north of 22.5N, excluding Med/Gulf, from monthly data Volume-weighted average salinity of the 18C water as a function of month. Annual Maximum mixed layer depth within the Labrador sea and the T,S properties of that mixed layer. Suggested MLD defined as surface temperature - 0.1C (Rather poor results)

  37. Unfiltered

  38. Unfiltered

  39. SST in boxes

  40. Bermuda-Labrador Basin Transport Index Curry and McCartney, JPO 2001

  41. TBD Model standards: a recommendation from WGOMD about model standards that should be followed by assimilation/synthesis efforts would be welcome. Forcing standards: it is intended to provide a flux reference data set against which estimates of surface fluxes can be evaluated. Again a statement about which surface flux fields (e.g., which bulk formula) should be used, would be helpful. Reference data sets are required for assimilation an model evaluation. We need input from WGOMD about what and how is required from CLIVAR DAAC’s.

  42. 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. Reference Data Sets

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