Met Office Hadley Centre observations datasets
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The Met Office Hadley Centre's sea surface temperature data set, HadSST. is a monthly global field of SST on a 5° latitude by 5° longitude grid from 1850 to date. The data have been adjusted to minimise the effects of changes in instrumentation throughout the record. The data set is presented as a set of interchangeable realisations that capture the temporal and spatial characteristics of the estimated uncertainties in the biases. In addition there are files providing the measurement and sampling uncertainties which must be used in addition to the ensemble to obtain a comprehensive estimate of the uncertainty. The data are not interpolated.

The data set initially runs from 1850 to presnet with regular monthly updates.

Brief description of the data

The SST data are taken from release 3.0.0 of the International Comprehensive Ocean-Atmosphere Data Set, ICOADS (external web page), from 1850 to 2014 and from ICOADS release 3.0.1 from 2015 onwards. From January 2016, these are supplemented by drifting buoy observations "Generated using E.U. Copernicus Marine Service Information" from CMEMS (Copernicus Marine Environment Monitoring Service). HadSST. is produced by taking in situ measurements of SST from ships and buoys, rejecting measurements that fail quality checks, converting the measurements to anomalies by subtracting climatological values from the measurements, and calculating a robust average of the resulting anomalies on a 5° by 5° degree monthly grid. After gridding the anomalies, bias adjustments are applied to reduce the effects of changes in SST measuring practices. The uncertainties arising from under-sampling and measurement error have been calculated for the gridded monthly data as have the uncertainties on the bias adjustments following the procedures described in the paper.

Comparison of HadSST4 to instrumentally homogeneous series

Update of Figure 11 from the paper shows a comparison between HadSST. in black (grey shading indicated 95% uncertainty range) and three instrumentally homogeneous data sets: (a) Argo(purple), (c) ARC (red), and (e) Buoys (blue). Panels (b), (d) and (f) show the coverage of each data set, with HadSST4 in grey and the comarison data sets with colours as in panels (a,c,e).

Go to download page Data are available from the download page without charge under the Open Government Licence v3. Please read the terms and conditions.


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

Kennedy, J. J., Rayner, N. A., Atkinson, C. P., & Killick, R. E. (2019). An ensemble data set of sea‐surface temperature change from 1850: the Met Office Hadley Centre HadSST. data set. Journal of Geophysical Research: Atmospheres, 124.

Product User Guide

An introduction to the data set is available as a pdf, which includes a "quick start" guide as well as more inx depth material including how to work with the uncertainty information.

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Other information

Dataset produced in collaboration with:

Met Office ICOADS