CLIVAR/GSOP Activities

1. CLIVAR/GSOP Activities OOPC-12 May 3-5, 2007

2. GSOP TOR • 1. Develop, promote and seek to implement strategies for a synthesis of global ocean, atmosphere and coupled climate information through analysis and reanalysis efforts and through the use of other techniques where appropriate. Initial emphasis will be on global ocean synthesis efforts, building on previous experiences and developments. • 2. Be responsible for the definition and fulfilment of CLIVAR's global needs for sustained observations (in collaboration with relevant WMO and IOC bodies, including GCOS, GTOS, GOOS, AOPC and OOPC, and JCOMM), and for the development of a strategy for their evolution/optimization based on new science and reanalysis insights, and fostering the use of resulting data sets in global synthesis efforts. • 3. Promote activities to develop the surface flux data sets required by CLIVAR in liaison with the WGNE, global atmospheric reanalysis efforts and the WCRP Working Group on Surface Fluxes. • 4. Provide an overview of and directions to CLIVAR data management and information activities in collaboration with other WCRP projects and in liaison with CLIVAR-relevant data centres and DACS and the ICPO. • 5. Liaise and collaborate with CLIVAR Panels and Working Groups in identifying the requirements for and coordinating the development of an observing system for CLIVAR.

3. The Global Synthesis and Observations Panel (GSOP) was setup in 2004 with the task to oversee CLIVAR’S ocean synthesis and data management activities. • The Panel Terms of Reference are: • 1. Develop, promote and seek to implement strategies for a synthesis of global ocean, atmosphere and coupled climate information through analysis and reanalysis efforts and through the use of other techniques where appropriate. Initial emphasis will be on global ocean synthesis efforts, building on previous experiences and developments. • 2. Be responsible for the definition and fulfilment of CLIVAR's global needs for sustained observations (in collaboration with relevant WMO and IOC bodies, including GCOS, GTOS, GOOS, AOPC and OOPC, and JCOMM), and for the development of a strategy for their evolution/optimization based on new science and reanalysis insights, and fostering the use of resulting data sets in global synthesis efforts. • 3. Promote activities to develop the surface flux data sets required by CLIVAR in liaison with the WGNE, global atmospheric reanalysis efforts and the WCRP Working Group on Surface Fluxes. • 4. Provide an overview of and directions to CLIVAR data management and information activities in collaboration with other WCRP projects and in liaison with CLIVAR-relevant data centres and DACS and the ICPO. • 5. Liaise and collaborate with CLIVAR Panels and Working Groups in identifying the requirements for and coordinating the development of an observing system for CLIVAR.

4. WCRP Strategic Framework • Move from physics-only to Earth-System models (with IGBP) • Prediction across all timescales “seamless prediction”. • Develop sustained climate observing system with GCOS, GEOSS… • Integration of models and data • Use of data assimilation to initialize models over widest range of climate prediction timescales possible • Synthesis through reanalysis (atmosphere, ocean, coupled) • Link to applications through existing mechanisms (e.g. START, WCAP) & new ones

5. SSG-14 • Sought development of CLIVAR Roadmap against science themes of ENSO/TV, Monsoons, Decadal/THC, ACC, Role of Oceans in Climate, Global Modeling & Prediction. • Was organized around a series of mini-assessments of current status of each themes. • Background of sponsor/context setting WCRP, IOC, WMO, IGBP

6. CLIVAR Road Map - key timescales/issues IPCC AR5, (Assume Report by 2013 with inputs by 2011) CLIVAR “sunset date” of 2013 - what will be the legacy of CLIVAR What will follow CLIVAR (and sunsets of other WCRP Projects - issue for the JSC)

7. CLIVAR Road Map - key element: • Development of ocean reanalyses + coupled reanalysis concept (with WOAP) including d/a aspects. • Realization of multiple model reanalyses. • Input to AR5 development of coupled reanalyses. • Syntheses as part of “CLIVAR legacy; initial coupled reanalyses

8. Ocean observations/CLIVAR • Continue close cooperation with OOPC & others through CLIVAR Basin Panels and CLIVAR Global Synthesis & Observation Panel to develop sustained ocean observing system • Complete & validate multiple global reanalyses in time for IPCC AR5; assess ocean component of coupled reanalyses • Stimulate international activity to evaluate the current state & development vector of the global ocean observing system (revisit OceanObs’99 in 2008 timeframe?) • Aim by the end of CLIVAR to have: • Developed a global description of subsurface ocean variability • Have in place a truly global ocean observation system

9. Ocean observations/CLIVAR • SSG to work on 2013 vision/legacy & develop data management requirements • Choose a few foci crafted around the ocean’s role in climate: e.g. • Exchange (with atmosphere); including joint global flux project (with GEWEX) focused around water cycle • Storage (heat/salt/CO2) • Transports and utilise new observing capabilities to develop key datasets for CLIVAR legacy • Develop common climate indices for models/observations as component • Develop concept of post-CLIVAR activity (with GEWEX/IGBP). Possible theme of data synthesis decade post-CLIVAR

10. SSG-14 Actions for GSOP Lend CLIVAR support to the campaign to create an Ocean Observation System Centre (to be expanded in discussion of roadmap) (SSG co-chairs, ICPO). GSOP to identify and and coordinate development of CLIVAR reference data sets, including error bars where possible, and develop ideas on how to make them widely accessible. (GSOP) Develop plans for an "OceanObs 200X" and consult potential sponsors regarding sponsorship. To be seen as part of CLIVAR annual workshop devoted to the Oceans' role in climate; include issues such as Ocean Obs Data Centre, measurement of ocean currents and transports, etc. (GSOP)

11. Second Global Synthesis and Observations Panel meetingLa Jolla, CA, USA08 - 09 December 20006 • Report from CLIVAR SSG and CLIVAR Roadmap (Detlef Stammer) • OOPC-11 (Albert Fischer) • WOAP-2 (Detlef Stammer) • WCRP/COPES Sea Level Workshop (Stan Wilson) • Repeat Hydrography Workshop (Masao Fukasawa) • CLIVAR Synthesis Workshop (Detlef Stammer) • Global Carbon and Synthesis needs (Chris Sabine) • Global heat content (Josh Willis) • Shallow overturning in the Pacific (Mike McPhaden) • Trends in mid-latitude ocean circulation (Wenju Cai) • Climate Impacts of Subantarctic Mode Water and Antarctic Intermediate Water: Pathways (Bernadette Sloyan) • Atlantic (Martin Visbeck) • Indian (Mike McPhaden) • Pacific (Axel Timmermann) • Southern Ocean (Sarah Gille) • Arctic Ocean / IPY (Vladimir Ryabinin) • Review of CLIVAR data sets and data centres (David Legler) • Flux evaluation guidelines (Shawn Smith) • Sea Surface Salinity (Detlef Stammer) • OOPC/CLIVAR climate indices (Albert Fischer) • Ocean observations and societal relevance (Dean Roemmich) • Future activities: Velocity workshop, Upper Ocean Thermal Review, OceanObs0X

12. Second Session of the Global Synthesis and Observations PanelLa Jolla, CA, USA, 8-9 December 2006 • Develop data release specification, quality and timeliness for each major data stream (M. McPhaden to lead) • CCHDO and ICPO to strengthen contact with NODCs in order to facilitate flow of hydrographic data (ICPO, CCHDO) • GSOP co-chairs to write to ICPO Director endorsing the JCOMMOPS Ocean Observation System Centre (GSOP co-chairs) • Albert Fischer to circulate JCOMM document that discuss the expansion of JCOMMOPS, and GSOP co-chairs to comment on it. (A. Fischer, GSOP co-chairs) • Summarise a document with data streams timeliness, and write an article to Exchanges (ICPO, GSOP co-chairs) • White paper on CLIVAR datasets, identifying gaps and prioritise focus on data streams. Circulate to GSOP members for comments (D. Stammer, D. Roemmich, D. Behringer) • Contact basin panels encouraging the use of ocean synthesis outputs (ICPO) • Consult with David Anderson on his availability and report to WOAP. (D. Stammer)

13. Contact basin panels to review indices used in the ocean synthesis effort (D. Stammer, ICPO) • Start discussion of a strategy for ocean synthesis with group leads from the CLIVAR/GODAE Synthesis meeting (D. Stammer) • GSOP to recommend to CLIVAR SSG the need of a carbon representative to GSOP (D. Stammer) • Start plans to develop a small pilot project for joint synthesis activities between GSOP and Carbon community (D. Stammer, C. Sabine) • Liaise with OOPC regarding coordinated way in voicing sustainability of the observing system (GSOP co-chairs) • Co-chairs to write to (???) promoting the ideas of sustained observing system in the Indian Ocean and free/open exchange data, particularly from India (GSOP co-chairs) • GSOP to start planning with ocean synthesis/reanalysis groups on the assimilation of IPY-generated dataset (D. Stammer, A. Weaver) • Prepare a data requirements document with identification of needs and suggestion of specific tasks (D. Legler, D. Stammer) • GSOP to endorse FSU activity of intercomparison of global fluxes (GSOP co-chairs to write to S. Smith) • Include links to ocean heat and freshwater transport estimates on GSOP’s webpage (N. Caltabiano, S. Josey, S. Smith) • Invite panels to provide the “top five” indices from observations and proposed some new indices, and liaise with OOPC (ICPO) • Draft a white paper on the societal relevance of the ocean observing system and circulate to panel for comments (D. Roemmich, D. Stammer) • GSOP co-chairs to write to Alex Ganachaud and Rick Lumpkim inviting them to develop the rationale for an ocean velocity workshop (GSOP co-chairs)

14. 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.

15. 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.

16. 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: 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.

17. 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.

18. 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.

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

25. K-7 Global Heat Transport Ganachaud&Wunsch(1996)

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

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

28. K-7 Heat transport 25oN

29. Heat transport 48oN K-7

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

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

32. Max. MOC 48oN K-7

33. ECCO-50y

34. SODA

36. SST in boxes

39. 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

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

41. Unfiltered

42. Unfiltered

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

45. 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). • GSOP Web site to present climate indices from ocean syntheses over last 50 years (counter part to OOPC indices from data alone).

46. 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).

47. 2nd Synthesis Evaluation • Possible dates: Sept. 24/25 • Think about reasons for existing differences in syntheses and try to pin them down a bit more. • Start a discussion about error information required as input to the assimilation approaches and required to complement the estimated fields. • Think about what CLIVAR needs and what we have. That might include also initialization of coupled models or even coupled model assimilation. • We might want to address ice assimilation as well. • Produce recommendations with regard to future synthesis resource planning and recommendations for CLIVAR data processing and management. • Stimulation for WGOMD and IPCC to join in.