NOAA Optimum Interpolation (OI) Sea Surface Temperature (SST) V2

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One-Line Description:

  • NOAA Optimum Interpolation (OI) Sea Surface Temperature (SST) V2

Temporal Coverage:

  • Weekly means from 1981/10/29 to 1989/12/28.
  • Weekly means from 1989/12/31 to present.
  • Monthly means from 1981/12 to present.
  • Long term monthly means, derived from data for years 1961 - 1990.
  • Long term monthly means, derived from data for years 1971 - 2000.

Spatial Coverage:

  • 1.0 degree latitude x 1.0 degree longitude global grid (180x360).
  • 89.5N - 89.5S, 0.5E - 359.5E.

Levels:

  • Sea Surface

Update Schedule:

  • Weekly
  • Monthly

Download/Plot Data:

Variable Statistic Level Download File Create Plot/Subset
Sea Surface Temperature Mean Surface sst.wkmean.1981-1989.nc
sst.wkmean.1990-present.nc		 plot
Ice Concentration Mean Surface icec.wkmean.1981-1989.nc
icec.wkmean.1990-present.nc		 plot
Normalized Error Variance Mean Surface err.wkmean.1981-1989.nc
err.wkmean.1990-present.nc		 plot
Sea Surface Temperature Mean Surface sst.mnmean.nc plot
Ice Concentration Mean Surface icec.mnmean.nc plot
Sea Surface Temperature Long Term Mean Surface sst.ltm.1961-1990.nc
sst.ltm.1971-2000.nc		 plot
Land Sea Mask Mask Surface lsmask.nc plot

Usage Restrictions:

  • None

Detailed Description:

  • The Climate Diagnostics Center has collected and made available in (COARDS and CF-1.0 compliant) netCDF files, the weekly, monthly NOAA OI SST V2 data and monthly long-term mean from NCEP (Y. Xue) based on the V2 data.
    Weekly Data
    The optimum interpolation (OI) sea surface temperature (SST) analysis is produced weekly on a one-degree grid. The analysis uses in situ and satellite SST's plus SST's simulated by sea-ice cover. Before the analysis is computed, the satellite data is adjusted for biases using the method of Reynolds (1988) and Reynolds and Marsico (1993).
    The dates used in the netCDF files are the dates of the beginning of the 7-day average period. For the more recent period, 1990-present, the weeks are defined to be centered on Wednesday. During the period 1981-1989, the weeks are centered on Sunday.

    The latitude/longitude values in the netCDF coordinate variables are the centers of the grid cells.
    The ice field shows the weekly median ice concentration values input to the SST analysis. Ice concentration is stored as the percentage of area covered. For the ice fields, the land and coast have been set to the netCDF missing value. Note, the ice land mask is a function of the ice analysis and may change periodically.
    The OI analysis is done over all ocean areas and the Great Lakes. There is no analysis over land. The land values are filled by a Cressman interpolation to produce a complete grid for possible interpolation to other grids. The ocean and land areas are defined by a land sea mask (the lsmask.nc file). Land values for sst do not necessarily coincide with land values from ice analysis.
    Monthly Data
    The NOAA OI.v2 SST monthly fields are derived by a linear interpolation of the weekly optimum interpolation (OI) version 2 fields to daily fields then averaging the daily values over a month. The monthly fields are in the same format and spatial resolution as the weekly fields.
    The ice field shows the approximate monthly average of the ice concentration values input to the SST analysis. Ice concentration is stored as the percentage of area covered. For the ice fields, the land and coast grid cells have been set to the netCDF missing value.
    Monthly Long-term mean Data
    A climatology based on these fields was derived by Yan Xue of the NCEP Climate Prediction Center following the technique of Reynolds and Smith (1995) and Smith and Reynolds (1998). The climatology is available here in the sst.ltm.*.nc files.
    For more information see http://www.emc.ncep.noaa.gov/research/cmb/sst_analysis/.

Caveats:

  • The current weekly means are generally one week behind the current date.

Related File Naming & Structure Information:

File Names:

  • var.stat.time.nc   (In directory: /Datasets/noaa.oisst.v2/)

Dataset Format and Size:

  • CDC standard NetCDF 55 Mbyte file for each weekly 1981-1989 file (packed).
  • CDC standard NetCDF >110 Mbyte file for each weekly 1990-present file (packed).
  • CDC standard NetCDF >38 Mbyte file for each monthly file (packed).
  • CDC standard NetCDF 2 Mbyte file for each LTM file (packed).
  • CDC standard NetCDF 133 Kbyte file for each mask file.

Missing Data:

  • Missing data is flagged with a value of 32767s.
  • Land and coast set to missing for ice fields.
  • SST land areas can be masked using the lsmask.nc file.

Citation:

  • Please note: If you acquire NOAA_OI_SST_V2 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 NOAA_OI_SST_V2 data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at http://www.cdc.noaa.gov/ 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 NOAA_OI_SST_V2 data set freely available online in the future. Thank you!

References:

Original Source:

  • Climate Modeling Branch W/NP24
    NCEP/NWS/NOAA
    5200 Auth Road, Room 807
    Camp Springs, MD 20746 USA

Contact:

  • Physical Sciences Division: Data Management
    NOAA/ESRL/PSD
    325 Broadway
    Boulder, CO 80305-3328
    esrl.psd.data@noaa.gov