Briefing for U.S. Senate Staff

1
Data Archives for Atmospheric Research

• Briefing for U.S. Senate Staff
• Steven Worley, CISL/NCAR

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Outline

• Research Data Archive, definition and metrics
• A few samples
• Stewardship activities
• What we do
• What we dont do

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Research Data Archive (RDA) definition

• Collection of reference datasets used in
  atmospheric and related sciences
• Over 600 datasets
• 10-20 new datasets added annually
• First established about 40 years ago
• Basic metrics
• 548K files
• 100.5 TB
• 2-3K unique users annually

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What types of data?

• Conventional Observations, global
• Land surface and upper air soundings
• Marine surface, upper air sounding, and
  subsurface profiles

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What types of data?

• Operational Atmospheric Analyses, global
• NWP from U.S. and Europe
• Research Atmospheric Reanalyses, global
• Like NWP work, but much better for climate
  studies
• More and varied data with better QC
• Long time period (25-50 years) analyzed with a
  fixed assimilation scheme and model
• Focused analyses single data types

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Content additions

• 70 collections updated annually
• Some weekly
• Mainly modern period extensions
• Recover data from historical time periods
• Data exchanges in U.S. and internationally
• Rescue data from old magnetic media
• Promote and collaborate in digitization efforts

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Land Surface Data
1900
1925
1950
1975

• poor global prior to 1950
• 1950, low China, Canada, S. America
• -300 for 1975 to 2000
• Russia
• Australia

2000
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Upper Air Data
1960
1950
1970
1980
1990
1998
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Marine Surface Data
ICOADS, One day observation distribution January
15 of the year shown
1960
1970
1990
1980
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Stewardship - What we do

• Collect, archive, and document the data
• Organize the data for research
• E.g. synoptically sort
• Correct systematic errors
• Fix station position and elevations
• Hydrostatic check profiles, fix ordering
• Broad climatic range checks, label grossly
  erroneous data
• Collaborate with sister organizations to improve
  archives
• U.S., NOAA (NCEP, NCDC, NODC), NASA (GSFC,JPL),
  plus others
• International ECMWF, JMA, MPI, CMA, RIHMI, plus
  others

My worst nightmare, International restriction on
data distribution Have WMO Res. 40 Always being
challenged - countries want big for data
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Stewardship - What we dont do

• Adjust data for observing system changes
• Instruments vary in type, distribution, and
  accuracy
• Measurement homogenizing is a science and
  statistical problem
• Analyze irregularly space observation onto grids
• E.g. create a latitude/longitude grid of SST
• Target space and time scales dictate appropriate
  methods
• Blend satellite data with observations
• Increase global temporal and spatial coverage
  since 1979
• Bias adjust satellite data for
• Atmospheric aerosols, water vapor, volcanic dust,
  etc
• Big and complex problems - leave to world experts

However, we do collect and offer these
specialized data products to the community
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• Conclusion
• Building research data archives is critical for
  documenting and understanding the climate. Our
  historical data records can be greatly improved.
  We intend to stay on course to meet this
  challenge.