CRUTEM3 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 CRUTEM3 (the best estimate data are unchanged). If you have downloaded CRUTEM3 before November 20th 2007 please see this page.

We've recently corrected a minor bug in the error ranges provided for CRUTEM3 (the best estimate data are unchanged). If you have downloaded CRUTEM3 before October 27th 2006 please see this page.

CRUTEM3 is a gridded dataset of global historical land 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.

The gridded data are based on an archive of monthly mean temperatures provided by more than 4000 weather stations distributed around the world. Each station temperature is converted to an anomaly from the 1961-90 average temperature for that station, and each grid-box value is the mean of all the station anomalies within that grid box. As well as the mean anomaly, estimates are made of the uncertainties caused by poor measurements, uncertainties in the station data, sampling uncertainties caused by the limited number of measurements available, and large-scale biases such as urbanisation. 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. (Copyright 2006 AGU) (PDF)

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.

Frequently Asked Questions.

Dataset produced in collaboration with:

Maintained by: John Kennedy Last updated: 6/3/2007 Expires: 6/3/2008 Hosted by: Met Office Hadley Centre for Climate Change

© Crown Copyright