About the sea surface temperature timeseries graphs

Analyses available

Global Sea Surface Temperature (SST) timeseries are available from 1900 to present. A full ocean domain of global sea surface temperature from 88°S to 88°N is displayed by default, but the standard diagnostic global ocean from 60°S to 60°N is also available from the Region drop-down list. Seasonal means are December-February (DJF), March-May (MAM), June-August (JJA) and September-November (SON).

Note that global sea surface temperature timeseries are presented as anomalies relative to the 1961-1990 climatology period by default. A more recent climatology period of 1991-2020 is also available for selection.

Data used

Since December 2017, the sea surface temperature timeseries are calculated from the NOAA Extended Reconstructed Sea Surface Temperature Version 5 (ERSST v5) data provided by the NOAA/OAR/ESRL PSL, Boulder, Colorado, USA. A full description of the ERSST v5 data can be found in Huang et al., (2017), with the earlier ERSST v4 described in Huang et al., (2015) and Liu et al., (2015). The ERSST v5 dataset metadata catalogue entry and identifier is doi:10.7289/V572FNM.

Changes from v4 to v5 include the use of new data sources (such as Argo floats above 5 meters) and new versions of input datasets, such as ICOADS R3.0 and HadISST2 sea ice concentration. Improved methodologies have been applied, such as the inclusion of additional statistical modes, less spatial-temporal smoothing, better quality control method, and bias correction with baseline to modern buoy observations. The new version improves the spatial structures and magnitudes of El Nino and La Nina events.

Between November 2016 and March 2020 the ERSST v5 dataset was impacted by the reduction of the number of drifting buoy reports into the ICOADS Near-Real-Time product (R3.0.1). This was noted on the NOAA ICOADS website. In March 2020 an updated dataset (ICOADS 3.0.2) that incorporates more complete drifting buoy reports was implemented into ERSSTv5. Data since 2008 have been changed.

The actual data values used to produce each graph are available via the "Raw dataset" link. The format for these data is:

    <start year><start month><end year><end month>   <mean sst anomaly (°C)>

The "Sorted dataset" link provides the timeseries as a sorted list in order to place recent values in historical context.

Please note that any use of these analyses should be acknowledged to the Bureau of Meteorology and the institutions listed above. Apart from the purposes of study, research, criticism and review, no part of these data may be reproduced, or redistributed for any commercial purposes, or distributed to a third party for such purpose, without written permission from the Director of Meteorology.

Further information

Huang, B., P.W. Thorne, V.F. Banzon, T. Boyer, G. Chepurin, J. Lawrimore, M.J. Menne, T.M. Smith, R.S. Vose and H.-M. Zhang, 2017: Extended Reconstructed Sea Surface Temperature version 5 (ERSST.v5): Upgrades, validations and intercomparisons. Journal of Climate doi:10.1175/JCLI-D-16-0836.1

Huang, B., V.F. Banzon, E. Freeman, J. Lawrimore, W. Liu, T.C. Peterson, T.M. Smith, P.W. Thorne, S.D. Woodruff and H.-M. Zhang, 2015: Extended Reconstructed Sea Surface Temperature version 4 (ERSST.v4): Part I. Upgrades and intercomparisons. Journal of Climate 28:3, 911-930 doi:10.1175/JCLI-D-14-00006.1

Liu, W., B. Huang, P.W. Thorne, V.F. Banzon, H.-M. Zhang, E. Freeman, J. Lawrimore, T.C. Peterson, T.M. Smith and S.D. Woodruff, 2015: Extended Reconstructed Sea Surface Temperature version 4 (ERSST.v4): Part II. Parametric and structural uncertainty estimations. Journal of Climate 28:3, 931-951 doi:10.1175/JCLI-D-14-00007.1