HadCRUT3 dataset

We have recently changed the way that the smoothed time series of data were calculated. Data for 2008 were being used in the smoothing process as if they represented an accurate esimate of the year as a whole. This is not the case and owing to the unusually cool global average temperature in January 2008, it looked as though smoothed global average temperatures had dropped markedly in recent years, which is misleading.

We've recently corrected a minor bug in the error ranges provided for HadCRUT3 (the best estimate data are unchanged). If you have downloaded HadCRUT3 before November 20th 2007 please see this page.

We've recently corrected a minor bug in the error ranges provided for HadCRUT3 (the best estimate data are unchanged). If you have downloaded HadCRUT3 before October 27th 2006 please see this page.

HadCRUT3 is a gridded dataset of global historical surface temperature anomalies. Data are available for each month since January 1850, on a 5 degree grid. The dataset is a collaborative product of the Met Office Hadley Centre and the Climatic Research Unit at the University of East Anglia.

Brief description of the data

The gridded data are a blend of the CRUTEM3 land-surface air temperature dataset and the HadSST2 sea-surface temperature dataset. As well as a best-estimate valuue for the surface temperature, a comprehensive set of uncertainty estimates are available. The image below shows near surface temperature anomalies for the most recent available month. A plus sign in any grid box indicates that the temperature anomaly in that grid box this month is the highest since the dataset starts in January 1850. Similarly a minus sign signals the lowest anomaly since 1850.

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. Commercial and media enquiries You can access the Met Office Customer Centre, any time of the day or night by phone, fax or e-mail. Trained staff will help you find the information or products that are right for you. Contact the Met Office Customer Centre References When using the data set in a paper, the following is the correct citation to use: P. Brohan, J.J. Kennedy, I. Harris, S.F.B. Tett and P.D. Jones, Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850. J. Geophys. Res, 111, D12106, doi:10.1029/2005JD006548. (pdf 1.2Mb)

Other information

Various diagnostics are produced from the monthly gridded fields. These include images of monthly anomaly patterns, and global, regional and local time-series.

Dataset produced in collaboration with:

Maintained by: John Kennedy Last updated: 23/02/2008 Expires: 23/02/2009 Hosted by: Met Office Hadley Centre for Climate Change

© Crown Copyright