Sea surface temperature from HadISST1

HadISST monthly global SST, Jan 1870. Copyright: UHH/CEN/AJB

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Access

RESTRICTED: This link to the data set is only available for a restricted user group. The data set is only accessible in CEN/MPI net or accessible from external nets with a customer account. Please contact ICDC if you would like to access this data from outside the network.

View HadISST data at LAS
Access HadISST data via OPeNDAP
Data access via file system: /data/icdc/ocean/hadisst1/

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Description

The HadISST1 data set is a blend of historical SST and modern SST observations from ships, buoys, drifters, etc. and sea ice observations, partly from historical ship- and air-borne and partly from satellite data.

Global mean Hadley SST — Fig. 1: Time series of the global mean HadISST SST (Hadley SST). Copyright: UHH/CEN/S. Kern

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, see references) 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.

For a detailed description of the dataset, see the web page at the Hadley Centre and the paper by Rayner et al. (see references).

The top right figure 1 shows the time series of the global mean HadISST SST. We note explicitely that this time-series is based on a simple arithmetic mean of the SST of the ice-free grid cells without any weighing with information about data density and quality - like is used to create the global SST and temperature anomalies of the HadCRUT and CRUTEM data sets.

Last update of data set at ICDC: August 15, 2024

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Parameters

Parameters of the HadISST data set
Name	Unit
SST	°C
Sea ice cover	%

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Coverage, spatial and temporal resolution

Period and temporal resolution:

1870-01 to 2024-06
Monthly

Coverage and spatial resolution:

Global
Spatial resolution: 1.0° x 1.0°, cartesian grid
Geographic latitude: -89.5°N to 89.5°N
Geographic longitude: -179.5°E to 179.5°E
Dimension: 360 columns x 180 rows
Altitude: 0.0 m

Format:

NetCDF

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Data quality

The offered data set does not include uncertainty estimates. Information about uncertainties are, however, given in the two publications listed in the references section.

In addition we cite two notions from the metoffice data set web page here:

"We have switched to using unadjusted (for continuity with the HadSST2 data previously used) HadSST4 as the basis for updates to the in situ data in HadISST. HadSST4 data are used for January 2021 onwards."

"We have changed the data source used to provide satellite SST retrievals. This was previously supplied by NOAA (as described in the HadISST paper). We now use SST retrievals from METOP which are extracted from the Met Office data base. The first month to use METOP data is June 2020 and every month thereafter. While we have found no obvious discontinuity in the mean or the appearance of the SST fields, a change of data source can introduce unexpected changes. Please be aware of this when using the data. Note that HadISST1 has a cool bias in recent years because no adjustment is made to account for changing ship biases and the known offset between buoy and ship measurements."

Investigations have revealed some inconsistencies which are discussed and summarized in the Technical Report (Chelton, 2016, see references).

ICDC recommends users of the HadISST1 data set to not use the sea ice concentration for quantitative investigations but only for qualitative purposes - e.g. for the delineation of the ice edge. Reasons for this are as follows:

The sea ice concentration data is based on an inhomogeneous number and type of data; only with begin of the satellite era in 1978/79 data for sea ice concentration retrieval have been available quasi-daily. This applies in particular for the Southern Ocean.
The Arctic sea ice concentrations contains artifacts.
1. Between November 1973 and February 1974 there is an inconsistency across the entire Arctic Ocean with unrealistic patches of around 90% and 100% sea ice concentration.
2. During late spring to early winter there is an unrealistic sea ice concentration gradient in the marginal ice zone. First the sea ice concentration increases from the ice edge towards the pack ice and eventually reaches 100%. But then there is a jump to values of 90% to 92% over large areas along the marginal ice zone before further to the north the sea ice concentration again increases towards 100%.

An alternative sea-ice concentration data set has been released: HadISST2; this data set can be downloaded at the Met Office Hadley Centre Website (see references).

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Contact

Nick Rayner
Met Office Hadley Centre, FitzRoy Road, Exeter, Devon EX1 3PB
United Kingdom
email: nick.rayner (at) metoffice.gov.uk

John Kennedy
Met Office Hadley Centre, FitzRoy Road, Exeter, Devon EX1 3PB
United Kingdom
email: john.kennedy (at) metoffice.gov.uk

Stefan Kern
University of Hamburg
email: stefan.kern (at) uni-hamburg.de

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References

Literature:

Chelton, D, Risien, C., Technical Report: Zonal and Meridional Discontinuities and Other Issues withthe HadISST1.1Datase, 2016, https://ir.library.oregonstate.edu/concern/defaults/kw52j9632
Rayner, N. A., Parker, D. E., Horton, E. B., Folland, C. K., Alexander, L. V., Rowell, D. P., Kent, E. C., and Kaplan, A. (2003), Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century, J. Geophys. Res., 108, 4407, doi:10.1029/2002JD002670, D14. https://doi.org/10.1029/2002JD002670
Brohan, P., Kennedy, J. J., Harris, I., Tett, S. F. B., and Jones, P. D. (2006), Uncertainty estimates in regional and global observed temperature changes: A new data set from 1850, J. Geophys. Res., 111, D12106, doi:10.1029/2005JD006548. https://doi.org/10.1029/2005JD006548

Websites:

ICOADS, https://icoads.noaa.gov/
Hadley Centre Sea Ice and Sea Surface Temperature data set (HadISST), Met Office Hadley Centre observations datasets, https://www.metoffice.gov.uk/hadobs/hadisst/

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Data citation, License, and Acknowledgments

Please cite the data as follows:

Rayner, N. A., Parker, D. E., Horton, E. B., Folland, C. K., Alexander, L. V., Rowell, D. P., Kent, E. C., and Kaplan, A. (2003) Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century, J. Geophys. Res., 108(D14), 4407, doi: 10.1029/2002JD002670

“HadISST data were obtained from https://www.metoffice.gov.uk/hadobs/hadisst/ and are © British Crown Copyright, Met Office, [year of first publication], provided under a Non-Commercial Government Licence http://www.nationalarchives.gov.uk/doc/non-commercial-government-licence/version/2/ ”.

Distributed in netCDF format by the Integrated Climate Data Center (ICDC), CEN, University of Hamburg, Hamburg, Germany [last access date: August 7, 2024].

and with the following acknowledgments:

Thanks to ICDC, CEN, University of Hamburg for data support.

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