ICOADS Long-Term Means

ICOADS has been updated from R2.5 to R3.0. The previous version will be available for a period of time.

Brief Description:

  • The International Comprehensive Ocean-Atmosphere Data Set (ICOADS) is the most extensive collection of surface marine data spanning the past three centuries, together with simple gridded monthly summary products extending from 1800 forward.

Temporal Coverage:

  • Long-term monthly means, and percentage of years with extant data making up each climatological mean value, derived from data spanning 1971 - 2000 and 1981 - 2010.
  • Long-term monthly means, derived from data for years 1950 - 1979.

Spatial Coverage:

  • 2.0 degree latitude x 2.0 degree longitude global grid (90x180).
  • 89.0N - 89.0S, 1.0E - 359.0E.


  • Sea Surface

Update Schedule:

  • Static

Download/Plot Data:

  • 1950 - 1979 long-term monthly means based on original COADS Release 1 (1854-1979) data.
    Variable Statistic Level Download File Create Plot/Subset
    Sea Surface Temperature (S) Long-Term Mean Surface sst.ltm.nc plot
    Air Temperature (A) Long-Term Mean Surface air.ltm.nc plot
    Scalar Wind (W) Long-Term Mean Surface wspd.ltm.nc plot
    U-wind (U) Long-Term Mean Surface uwnd.ltm.nc plot
    V-wind (V) Long-Term Mean Surface vwnd.ltm.nc plot
    Sea Level Pressure (P) Long-Term Mean Surface slp.ltm.nc plot
    Cloudiness (C) Long-Term Mean Surface cldc.ltm.nc plot
    Specific Humidity (Q) Long-Term Mean Surface shum.ltm.nc plot
    Relative Humidity (R) Long-Term Mean Surface rhum.ltm.nc plot
    Sensible Heat Parameter ([S-A]*W) Long-Term Mean Surface sflx.ltm.nc plot
    Latent Heat Parameter ([Qs-Q]*W) Long-Term Mean Surface lflx.ltm.nc plot
    U-wind Stress (U*W) Long-Term Mean Surface upstr.ltm.nc plot
    V-wind Stress (V*W) Long-Term Mean Surface vpstr.ltm.nc plot

Usage Restrictions:

  • None

Detailed Description:

  • Simple long-term monthly means, and percentage of years with extant data making up each climatological mean value, derived from ICOADS Release 2.5 enhanced data through 2007 and preliminary 2008 through present data. (note: Following the Release 2.5 end date data are based exclusively on real-time GTS data with minimal quality control. These data should be considered preliminary and will be subject to change in new releases.)
  • Simple long-term monthly mean files constructed from the original COADS Release 1 (1854-1979) data.
Please refer to the ICOADS Website for more information about the ICOADS project, observational and summary products, and associated metadata.


  • Small numerical biases in previous netCDF files are described here.

Related File Naming & Structure Information:

File Names:

  • var.stat[.perc].nc   (In directory: /Datasets/icoads/2degree/enh/LTMs1981-2010)
  • var.stat[.perc].nc   (In directory: /Datasets/icoads/2degree/enh/LTMs1971-2000)
  • var.stat.nc   (In directory: /Datasets/icoads/2degree/LTMs1950-1979)

Dataset Format and Size:

  • PSD standard NetCDF >392 Kbyte file for each long-term mean and percentage of years in climatology files (packed).
  • PSD standard NetCDF >781 Kbyte file for each long-term mean wspd3 file.

Missing Data:

  • Missing data is flagged with a value of 32766s.


  • Please note: If you acquire ICOADS data products from PSD, we ask that you acknowledge us in your use of the data. This may be done by including text such as ICOADS data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.esrl.noaa.gov/psd/ in any documents or publications using these data. We would also appreciate receiving a copy of the relevant publications. This will help PSD to justify keeping the ICOADS data set freely available online in the future. Thank you!


Original Source:

  • Multinational. The US contribution is the result of a cooperative project between the National Oceanic and Atmospheric Administration (NOAA)--specifically its Earth System Research Laboratory (ESRL), its National Climatic Data Center (NCDC), and the Cooperative Institute for Research in Environmental Sciences (CIRES), conducted jointly with the University of Colorado--and the National Science Foundation's National Center for Atmospheric Research (NCAR).


  • NetCDF questions:

    Physical Sciences Division: Data Management
    325 Broadway
    Boulder, CO 80305-3328
  • Data questions:

    Eric Freeman, Team STG, Inc./ERT
    NOAA National Centers for Environmental Information (NCEI)
    Center for Coasts, Oceans and Geophysics (CCOG)
    151 Patton Avenue
    Asheville, NC 28801-5001 USA
    Phone: +1 828-271-4463 (Fax: -4022)
    e-mail: Eric.Freeman@noaa.gov