CLIVAR Data Sets

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CLIVAR Data Sets

• David M. Legler
• August 31, 2006

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Introduction

• Motivation
• Data Requirements
• CLIVAR Reference Data Sets
• CLIVAR data centers (DACs)
• Other data centers and data of interest
• Summary and requirements questions

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Scientific Data Stewardship (SDS)

• Functions of a comprehensive SDS
• Real-time monitoring of obs system performance
  for long-term applications (e.g. detection of
  small biases in the instrumental records)
• Generates authoritative, long-term records
• Uses authoritative records to assess current
  state of the environment and put it into
  historical perspective
• Insures complete archival and access capabilities

Currently we do not have a complete SDS system
for ocean data
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Ocean Reanalysis Workshop (2004)

• Recommendation to develop data requirements for
  ocean reanalyses
• Such requirements could provide guidance to
  exiting CLIVAR (and other) data centers
• Provision of data
• Development of products
• Supplying other information (e.g. uncertainties,
  errors, biases)

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Data requirements for ocean syntheses

• Two purposes
• Assimilated observations/data
• Evaluation of assimilations and simulations
• What data??
• Which variables (all physical, some
  biogeochemical, acoustic, optical, etc)?
• Time span of interest (most likely 1950s to
  present)??
• Spatial extent (polar regions, marginal seas, and
  coastal regions?)
• Data information (e.g. metadata, quality
  information, biases, errors, etc) - how much do
  we need and who will provide it?

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Requirements

• How
• Do we identify authoritative set of records or
  allow a market-driven set of alternatives to
  develop?
• Collection and assemblage how organized and
  coordinated does it need to be?
• When
• Timeliness of provision of data and products?
• Aim for new generation of reanalyses products in
  time for next IPCC?

In order to make more orderly progress in
developing suitable data systems for ocean
syntheses, need to establish a timeline for major
ocean reanalyses activities
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CLIVAR Reference Data Sets

• Data and products
• Publicly available through known servers
• Highest quality against established standards
• Where possible, should include accuracy estimate
• Identified initially by CLIVAR basin panels,
  WGOMD, and data assimilation experts (see Stammer
  and Lee report)
• Not clear there is a data home for all these
  data sets (should there be?)

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Data Providers

• CLIVAR Data Assembly Centers (DACs)
• Other data centers (e.g. WDC, Intl Ctrs, Argo,)
• Aggregators/synthesis programs (e.g. GODAE,
  ENACT, )
• Researchers with products

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WOCE Data System
Data Assembly Centers (DACs) Special Analysis
Centers (SACs) Data Information Unit (DIU)
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Legacy of WOCE
WOCE V3 DVDs 2 DVDs, 12GB data 10 yrs of
in-situ satellite ocean data and
products netCDF-COARDS compliant files Consistent
and documented QC Common metadata stds,
conventions, etc. Search tool/file pointers
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CLIVAR and Data Management

• WOCE heritage CLIVAR has picked up some parts of
  the WOCE (ocean) data systemBUT CLIVAR is more
  than the oceans!
• CLIVAR is the home for
• Some observation system elements and their data
  systems
• Field experiment observation data (UCAR-JOSS)
• Numerous model and value-added products
• Various regional/system-wide data/product
  activities
• Many (not all) of these consider data management
  issues, but all should be encouraging and helping
  develop Scientific Data Stewardship activities
  for ocean data

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Reference data from limited observing studies
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CLIVAR DACs
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Hydrography, tracers
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ADCP
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Surface Drifters
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Current Meters
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Sea Level
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Surface Meteor/Air-Sea Fluxes
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Upper Ocean Thermal
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CLIVAR DACs

• Upper Ocean Thermal (XBT) MEDS, NOAA/AOML, AODC
• Drifters AOML and Meds
• Ocean surface topography,
• vector winds, and SST JPL and CERSAT
• Moorings BODC
• Sea Surface Salinity IFREMER
• Sea Level Univ Hawaii and BODC
• ADCP NOAA/Univ Hawaii JODC
• Marine Surface Meteorology Florida State
  University
• CLIVAR Carbon Hydrography Scripps

Increasing level of sustained institutional
support
The DACs assemble and distribute data metadata,
supply QC attributes, develop and distribute
products
Some DACs are not financially stable. Engagement
expressions of support would be helpful.
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Other data centers important for ocean syntheses

• NOAA-NODC
• NCAR
• NASA DAACs/ESA Data Ctrs
• APDRC
• TAO, OceanSites, GOSUD, GHRSST
• Etc.

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Yet more sources of data

• Aggregators and synthesis centers
• ENACT
• GODAE (and GODAE servers)
• Mersea
• .

• Are all data of interest accessible? Of known
  quality?What about the CLIVAR Reference Data
  sets?
• Lots of datais it sufficiently organized?

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Discussion

• Results presented at 2004 Reanalyses Workshop
  demonstrated that ocean syntheses are being
  produced
• What do we know and what can we learn from these
  analyses?
• How strongly is the utilization of these results
  linked to the quality and fidelity of the input
  data? of the evaluation products?
• What more needs to be done from the data and
  products point of view?

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My questions to prompt discussion of input for a
requirements document

• Which data require assembly and in what time
  frame?
• Are all data sufficiently integrated? Described
  by metadata? Bias-free?
• Do we need to bring more order to the ocean data
  base? Who has the authoritative collection of
  ocean observations (what does authoritative
  mean)?
• Sensitivity of assimilation products to different
  input data? (does it matter which XBT data sets
  are used? are quality flags required? what are
  the benchmarks for data quality?)
• What about the need for search/discovery tools?
• Which data centers are providing needed
  information?
• Which CLIVAR Reference data sets are not readily
  accessible or adequately described?
• What has been built already (e.g. ENACT) and
  could we build off of it rather than create
  something new?

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CLIVARs Role in Data Management

• Helps to develop and assess requirements of the
  systems that will deliver climate data, products,
  and information
• Implements some (e.g. ocean) elements of the
  observing system and their respective data
  management systems, the frontline for new obs
  technology and data systems
• Develops synthesis frameworks (e.g. data
  assimilation/reanalyses) that utilize (and
  assess) the climate observations, products, and
  information
• Contributes assembled data, products and their
  attributes
• Cooperates with other activities (DMAC, OTI,
  OOPC, etc) leading data system development
• Provides feedback on acceptable metadata and data
  models
• Help sustain current Data Assembly Centers
  (DACs), regional, and specialized data centers
• CLIVAR Global Synthesis and Observations Panel
  (GSOP) is the CLIVAR group charged with
  addressing data management issues. Second meeting
  is being planned (December 2006)

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Further Information
www.clivar.org
www.usclivar.org