JISAO data

NCEP optimal interpolation sea surface temperature and sea ice concentration
November 1981 - February 2006

Image of SST.
PostScript | JPEG
September 2001 eastern Pacific SST showing the equatorial cold tongue and warmer SSTs to the north. Contours: light and dark shading for SSTs of 19-20 and 17-18C, respectively; and contours for SSTs > 20C.

NOAA NCEP, the providers of this data set, have a very good WWW page documenting the data set and providing it in a binary format. From that WWW page:

The optimum interpolation (OI) sea surface temperature (SST) analysis is produced weekly on a one-degree grid. The analysis uses in situ and satellite SSTs plus SSTs 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). A description of the OI analysis can be found in Reynolds and Smith (1994). The bias correction improves the large scale accuracy of the OI.

In November 2001, the OI fields were recomputed for late 1981 onward. The new version will be referred to as OI.v2.

The most significant change for the OI.v2 is the improved simulation of SST obs from sea ice data following a technique developed at the UK Met Office. This change has reduced biases in the OI SST at higher latitudes. Also, the update and extension of COADS has provided us with improved ship data coverage through 1997, reducing the residual satellite biases in otherwise data sparse regions.

The data:

  • multiple formats
    IRI has both the SST and ice datasets, updated monthly, available in multiple formats.
  • netCDF
    At JISAO these files are at /home/disk/muggy/data/sst_ncep/oi
    All errors in the netCDF file are due to Todd Mitchell.
    monthly-mean sea surface temperature (40 Mb)
    monthly-mean sea ice concentration (40 Mb) Land values set to missing.
    land mask (1 water, 0 land) (<1 Mb)
  • Binary
    Monthly and weekly files are available through ftp.
    They are also available at the National Center for Atmospheric Research

    Reynolds, R. W., N. A. Rayner, T. M. Smith, and D. C. Stokes, 2002: An Improved In Situ and Satellite SST Analysis for Climate. J. Climate, 15, 1609-1625.

    March 2006
    Todd Mitchell ( mitchell@atmos.washington.edu )
    JISAO data