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Reconstituting the Ocean: a tale from U.S. JGOFS

Reconstituting the Ocean: a tale from U.S. JGOFS. Cyndy Chandler (MCG, WHOI) U.S. JGOFS Data Management Office and Ocean Carbon and Biogeochemistry Coordination and Data Management Office 10 August 2005. MBARI-MMI Marine Metadata Workshop Boulder, CO. Question:.

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Reconstituting the Ocean: a tale from U.S. JGOFS

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  1. Reconstituting the Ocean: a tale from U.S. JGOFS Cyndy Chandler (MCG, WHOI) U.S. JGOFS Data Management Officeand Ocean Carbon and Biogeochemistry Coordination and Data Management Office 10 August 2005 MBARI-MMI Marine Metadata Workshop Boulder, CO

  2. Question: What do users want from metadata anyway? This presentation will focus mostly on usage metadata. U.S. JGOFS DMO

  3. Topics in today’s presentation: • Introduction • What is U.S. JGOFS? • Ocean reconstitution explained • merged products • metadata U.S. JGOFS DMO

  4. What is U.S. JGOFS? U.S. Joint Global Ocean Flux Study • part of multinational JGOFS U.S. Global Change Research Program (US GCRP), Scientific Committee on Oceanic Research (SCOR), and International Geosphere-Biosphere Programme (IGBP) • long term (U.S. 1989-2005) • multidisciplinary (bio, chem, PO, geology) • process studies (U.S. 1989-1998), time-series, global surveys, synthesis and modeling, data management • investigate ocean carbon flux U.S. JGOFS DMO

  5. Lessons Learned . . . • metadata is of critical importance • accurate, complete, available with data • monitor emerging standards • define minimum metadata requirements • standards-compliant solutions where possible • complete metadata record enables reuse of data metadata assembly is time consuming, but is the key to enabling secondary (reuse) of data * U.S. JGOFS DMO

  6. metadata documentation providing answers to the who, what, where, when, why and how questions U.S. JGOFS DMO

  7. Lessons Learned . . . • quality assurance is an ongoing process • intense QA process during initial acquisition and ingestion into data system • problems discovered as data are utilized by others • insufficient or inaccurate metadata • process of data product synthesis becomes a valuable diagnostic tool for improving data quality U.S. JGOFS DMO

  8. Data Synthesis • merged data products • combine all data from the same sampling device for a defined geospatial area and time range“attempt to put the ocean back together” U.S. JGOFS DMO

  9. U.S. JGOFS Process Study Areas U.S. JGOFS DMO

  10. CTD photos let the frenzy begin! U.S. JGOFS DMO

  11. Arabian SeaNiskin Bottle Data 73 data entitiesfrom 6 cruises in 1995data contributed by 46 different PIs U.S. JGOFS DMO

  12. Results of Data Synthesis • merged products for bottle and CTD data • bottle data products include many parameters: Arabian Sea > 110 North Atlantic > 80 Equatorial Pacific > 110 Southern Ocean > 170 U.S. JGOFS DMO

  13. The Merging Process • establish rules • which data entities to combine? • common sampling device • what determines the columns and rows? • could not have merged this many different data entities without sufficient metadata U.S. JGOFS DMO

  14. Columns and Rows • each column contains data from a different parameter (variable) parameter names are uniquely defined by long name (definition of term), units (encoding) and methodology • rows are uniquely defined by X,Y,Z and T usually this could be done by matching time, longitude, latitude, depth, station, cast and bottle number U.S. JGOFS DMO

  15. LAS v6Property-DepthArabian SeaNitrate from merged product generated by DMO from in situ Niskin bottle data Property Depth U.S. JGOFS DMO

  16. The Challenge • the originating PI doesn’t need an explicit, written record of metadata during the initial analysis of their data • the metadata supplied with a data contribution is often insufficient to support secondary use of data U.S. JGOFS DMO

  17. Summary What do users want from metadata anyway? users require sufficient information to: • determine data of interest • determine quality of data source • answer basic meta questions: who, what, where, when, how (and sometimes why) U.S. JGOFS DMO

  18. U.S. JGOFS web sitehttp://usjgofs.whoi.edu U.S. JGOFS DMO

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