NOAA Optimum Interpolation Sea Surface Temperature Analysis

blue dot Analysis Description and Recent Reanalysis
Latest Plots and Plot Archives
Gridded Data via FTP
Climatology
Related Links
References
Contact Information
Frequently Asked Questions

Analysis Description and Recent Reanalysis

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).

Latest Plots and Plot Archives

Weekly Global SST Anomaly
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Tropical Pacific weekly mean and anomaly SSTs
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Monthly Global SST
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Monthly Global SST Anomaly
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Weekly Ship and Buoy Observations with estimated Ice Cover
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Weekly AVHRR SST Retrievals

The following links will take you to directories containing plots for past weeks/months.

Weekly Anomaly Plot Archive
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Tropical Pacific Weekly Mean and Anomaly Plot Archive
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Monthly Global SST Plot Archive
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Monthly Global SST Anomaly Plot Archive

You can make your own plots through the NCEP NOMADS Meteorological Data Server

Instructions to make maps are here
Instructions to make time series are here

Gridded Data via FTP

The weekly fields are available in binary files in:

ftp://ftp.emc.ncep.noaa.gov/cmb/sst/oisst_v2/

Monthly fields are available in:

ftp://ftp.emc.ncep.noaa.gov/cmb/sst/oimonth_v2/

Documentation with sample source codes to read the data are available as README files in the above directories.

The Data Support Section (DSS) of NCAR makes both available in ASCII at: http://dss.ucar.edu/datasets/ds277.0/data/oiv2/
The NCAR archives may not be updated in real-time. So we have made recent data in NCAR's ascii format available on our server at:
ftp://ftp.emc.ncep.noaa.gov/cmb/sst/oisst_v2/ASCII_UPDATE
and
ftp://ftp.emc.ncep.noaa.gov/cmb/sst/oimonth_v2/ASCII_UPDATE
for weekly and monthly fields respectively.

The NOAA Earth System Research Laboratory (ESRL) makes these data availabe in NETCDF at: http://www.cdc.noaa.gov/cdc/data.noaa.oisst.v2.html

Climatology

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). This climatology is described in:

http://www.cpc.noaa.gov/products/predictions/30day/SSTs/sst_clim.html

and available in:

ftp://ftp.cpc.ncep.noaa.gov/wd52yx/sstclim/