Description and Recent Reanalysis
Gridded Data via FTP
Frequently Asked Questions
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. For more
details, see Reynolds, et al (2002).
The weekly and monthly fields through June 2020 are available in binary files in:
Documentation with sample source codes to read the data are available as README files in the above directories.
CPC's archive currently starts in February 2020 and is available at:
Differences during the overlap period are small and can be attributed to a few ship or buoy observations that made it into one analysis and not the other.>
The Data Support Section (DSS) of NCAR makes both available in ASCII at: http://rda.ucar.edu/datasets/ds277.0/
A climatology based on the OI.v2 Reanalysis fields was developed at the Climate Prediction Center using the method of Reynolds and Smith (1995) and Smith and Reynolds (1998). The latest version is available at:
Questions about the climatology or the above site should be directed to Yan.Xue@noaa.gov
Reynolds, R.W., 1988: A real-time global sea surface temperature analysis. J. Climate, 1, 75-86.
Reynolds, R.W., 1993: Impact of Mount Pinatubo aerosols on satellite-derived sea surface temperatures. J. Climate, 6, 768-774.
Reynolds, R. W. and D. C. Marsico, 1993: An improved real-time global sea surface temperature analysis. J. Climate, 6, 114-119.
Reynolds, R. W. and T. M. Smith, 1994: Improved global sea surface temperature analyses. J. Climate, 7, 929-948.
Reynolds, R. W. and T. M. Smith, 1995: A high resolution global sea surface temperature climatology. J. Climate, 8, 1571-1583.
Smith, T. M. and R. W. Reynolds, 1998: A high resolution global sea surface temperature climatology for the 1961-90 base period. J. Climate, 11, 3320-3323.
R. W., N. A. Rayner, T. M. Smith, D. C. Stokes and W. Wang,
2002: An improved in situ and satellite SST
analysis for climate. J. Climate, 15, 1609-1625.
(no longer works for the Environmental Modeling Center but may answer questions as time permits)