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Contents:




SST from NOAASea Surface Temperature from NOAA NCEP

This dataset contains the National Center for Environmental Prediction (NCEP), formally the National Meteorological Center (NMC) Optimal Interpolation (OI) monthly mean sea surface temperature (SST) data (Reynolds and Smith, 1994) which starts with November 1981 and continues to the present. Also included are climatological values for each of the twelve months (Reynolds and Smith, 1995). The temperatures were derived over water areas on a 1° x 1° latitude and longitude world grid. An Optimal Interpolation (OI) analysis was used to combine measurements from satellite-borne instruments and in situ ship and buoy platforms. The monthly SST values are presented in two forms: the actual values, and as differences (anomalies) from the climatological temperatures for the month. These SST measurements provide a means of monitoring both the long- and short-term variability of the dynamic and thermodynamic properties of the ocean on a global scale. On this site, this relatively new OI SST dataset replaces the original Climate Analysis Center "blended" SST dataset (Reynolds, 1988). The OI analysis, derived on a 1° x 1° grid, shows greater regional detail than the "blended" analysis which was derived on 2° x 2° grid.

Documentation available on CD-ROM


The data is available on Volume 1 of the CIDC CD set.


temperature deviationsTemperature Deviations from University of East Anglia

Monthly Surface air temperature anomalies for the period 1851-1996 have been calculated by the Climate Research Unit (CRU) of the University of East Anglia, using data from several sources (Jones et al., 1986 a,  b &  c, and 1991). The anomalies consist of land and ocean temperature departures from the 1961-1990 reference period, and are given on a 5° x 5° world grid. Hemispherical and global monthly and annual means are also included starting with 1856. Please note that this dataset was recently revised (Jones, 1994); in the older dataset the reference period was 1951-1970, fewer stations were included, and the gridding method was a little different. This dataset is very important for climate change studies. Despite relatively poor data coverage initially and around the two World Wars, the generally cold end of the nineteenth century and substantial warming from 1920 to 1940 are clearly shown. Slight cooling of the Northern Hemisphere took place between the 1950s and 1994, but this was followed by a warming trend in the 1980s and 1990s (Parker et al., 1994; Jones, 1994).

The temperature records were obtained from various archives: the World Weather Records, published by the Smithsonian Institution (1927, 1935, 1947), and the U. S. Weather Bureau (1959-1982); material collected in the meteorological archives; and sea surface temperature data derived from the United Kingdom Meteorological Office's data bank (UKMO; Bottomley et al., 1990), and the Comprehensive Ocean Atmosphere Data Set (COADS; Woodruff et al., 1987). The data from the several sources were carefully examined and corrections were made to compensate for known measurement problems. A brief discussion of the necessary corrections is given in Jones et al. (1991) and Parker et al., (1994). Hansen and Lebedeff (1987) and Vinnikov et al. (1990) have also formed surface temperature anomaly datasets covering essentially the same period. All three datasets draw most of their land measurements from the same data archives and on hemispherical and global scales show similar temperature trends. The CRU East Anglia dataset is however unique in combining land and ocean temperature anomalies for long term analysis. Thus it shows regional mid ocean temperature anomalies that are suppressed in the land measurement only datasets. The corrections for the land measurements also differ among the three datasets; thus while the general trends of the three datasets are similar there are some differences.

For the convenience of the user, the Goddard Institute for Space Studies (GISS) Global Monthly and Annual Average Temperature Deviations are given for comparison purposes. Also available on this site is the Southern Oscillation Index. It is the normalised sea surface pressure difference between Tahiti and Darwin. The method of calculation is given in Ropelewski and Jones (1987). All missing Darwin data are infilled from Djakarta. Missing Tahiti data are infilled from Apia, Suva and Santiago. Because of the missing data, some of the years before about 1920 are slightly less reliable than the later values.

Documentation available on CD-ROM


The data is available on Volume 1 of the CIDC CD set.


southern oscillation index Southern Oscillation Index from University of East Anglia

Concerns have grown over recent years about the low-frequency fluctuations in the El Niño - Southern Oscillation (ENSO) and its possible modulation by the greenhouse effect. In order to gain a greater understanding of the longer term variability and influence of this near global, ocean-atmosphere phenomenon, attempts have been made to distinguish between wider ranging ENSO phases based on related eastern hemisphere events and more localised El Niño events, which influence only the immediate South American region. The Southern Oscillation Index (SOI) based on the Tahiti-Darwin mean sea level pressure difference is an important indicator in the study of these events.

The method of calculation for the SOI is given in Ropelewski and Jones (1987). There are various ways of differencing the Tahiti and Darwin data. All missing Darwin data are infilled from Djakarta. Missing Tahiti data are infilled from Apia, Samoa Suva, Fiji and Santiago, Chile. Because of the missing data, some of the years before about 1920 are somewhat less reliable than the later values.

Documentation available on CD-ROM


The data is available on Volume 1 of the CIDC CD set.


air temperature anomalies Global Mean Surface Air Temperature Anomalies from NASA GISS

Global mean monthly, seasonal and annual temperature anomalies are given. The anomalies are variations from the means determined for the base period 1951-1980. These data are an update of the analyses described by Hansen and Lebedeff (1987 & 1988). The input data for these analyses come from about 4000 meteorological stations around the world. This work was done at the Goddard Institute for Space Studies (GISS) by Dr. James Hansen and his colleagues. On their site, they update the analysis each month. The data for earlier months and years changes slightly as additional stations are added and as the preliminary data for the most recent months are replaced by final values. The annual-mean global-mean temperature anomaly in recent decades is estimated to have a two-sigma uncertainty of about 0.07 degrees C due to incomplete spatial coverage of stations. Thus the relative rank of different years is uncertain for years whose temperatures differ by less than that amount. At this Goddard site the tables are updated periodically, but not monthly. The complete GISS analysis considers regional as well as global mean temperature variations. In the brief summary presented at this site only the global means are given.

Documentation available on CD-ROM


The data is available on Volume 1 of the CIDC CD set.