Long-term observations of near surface air temperature and sea surface temperature play a key role for climate system analysis.
CRUTEM3 and CRUTEM4, HadCRUT3 and HadCRUT4, and the 1961-1990 temperature climatology (Land: CRU, Jones et al. 1999, Ocean: HadSST.18.104.22.168) which are offered via this website are gridded data sets of global historical land surface (and sea surface) temperature anomalies. HadCRUT4 and CRUTEM4 are from version 22.214.171.124. Data are available for each month since January 1850, on a 5 degree grid. The data sets are collaborative products of the Met Office Hadley Centre and the Climatic Research Unit at the University of East Anglia.
CRUTEM3 and CRUTEM4 are limited to land stations; HadCRUT3 (HadCRUT4) is a blend of the CRUTEM3 (CRUTEM4) land-surface air temperature data set and the HadSST2 (HadSST3) sea-surface temperature data set.
Common to all these data sets is that these display the anomaly of the respective observations relative to the period 1961-1990. First the anomaly of the station values is computed and then all anomalies are gridded into a 5° x 5° grid.
Last update of this data set at ICDC: October 26, 2018.