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Hadley Centre Sea Ice and Sea Surface Temperature data set (HadISST)

We are planning a new version of HadISST, and we would like advice from its users. We have plans for several improvements to both the SEA ICE and SEA SURFACE TEMPERATURE components, but we would also like to know what you think. If you have used HadISST, or plan to, please contact us and tell us what changes or improvements you would like in a new version. We can't guarantee to please everyone, but we will consider all suggestions.

The Met Office Hadley Centre's sea ice and sea surface temperature (SST) data set, HadISST1, replaces the Global sea Ice and Sea Surface Temperature (GISST) data sets, and is a unique combination of monthly globally-complete fields of SST and sea ice concentration on a 1 degree latitude-longitude grid from 1870 to date.

Fields for the month-before-last (see image below) are added to the data set on the 2nd of every new month (for users who need faster updates, there is a preliminary version available earlier). In the picture white areas represent land and 100% ice cover.

From May 2007 the data set of in situ measurements used in HadISST has changed. The MOHSST data set, which was previously used has been discontinued, and HadSST2 is now being used in its place. The two systems ran in parallel for several months prior to the changeover and no significant differences were seen.

Brief description of the data

The SST data are taken from the Met Office Marine Data Bank (MDB), which from 1982 onwards also includes data received through the Global Telecommunications System (GTS). In order to enhance data coverage, monthly median SSTs for 1871-1995 from the Comprehensive Ocean-Atmosphere Data Set (COADS) (now ICOADS) were also used where there were no MDB data. The sea ice data are taken from a variety of sources including digitized sea ice charts and passive microwave retrievals.

HadISST1 temperatures are reconstructed using a two stage reduced-space optimal interpolation procedure, followed by superposition of quality-improved gridded observations onto the reconstructions to restore local detail. The sea ice fields are made more homogeneous by compensating satellite microwave-based sea ice concentrations for the impact of surface melt effects on retrievals in the Arctic and for algorithm deficiencies in the Antarctic, and by making the historical in situ concentrations consistent with the satellite data. SSTs near sea ice are estimated using statistical relationships between SST and sea ice concentration.

For a detailed description of the dataset and its production process, see the cited paper (in references section). We recommended you read this before using the data.

	Data are available from the download page without charge for the purposes of private study and scientific research, but please read the terms and conditions. You do not have to register, but it will help us if you do.

For problems getting or understanding the data, or to suggest some improvement please leave feedback. If you find the data useful, please return and tell us what you did with it.

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References

When using the data set in a paper, the following is the correct citation to use:

Rayner, N. A.; Parker, D. E.; Horton, E. B.; Folland, C. K.; Alexander, L. V.; Rowell, D. P.; Kent, E. C.; Kaplan, A. (2003) Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century J. Geophys. Res.Vol. 108, No. D14, 4407 10.1029/2002JD002670 (pdf ~9Mb)

Other information

We are planning a new version of HadISST, and we would like advice from its users. We have plans for several improvements, but we would also like to know what you think. If you have used HadISST, or plan to, please contact us and tell us what changes or improvements you would like in a new version. We can't guarantee to please everyone, but we will consider all suggestions.

Various diagnostics are produced from the monthly gridded fields.

Dataset produced in collaboration with: