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Extended Reconstructed Sea Surface Temperature (ERSST) v4

The Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly sea surface temperature dataset derived from the International Comprehensive Ocean–Atmosphere Dataset (ICOADS). It is produced on a 2° × 2° grid with spatial completeness enhanced using statistical methods. This monthly analysis begins in January 1854 continuing to the present and includes anomalies computed with respect to a 1971–2000 monthly climatology. The newest version of ERSST, version 4, is based on optimally tuned parameters using the latest datasets and improved analysis methods.

Monthly and globally averaged ERSST v4 anomaly from 1854–2014. Note that the data are more reliable after the 1940s.

The monthly analysis extends from January 1854 to the present, but because of sparse data in the early years, there is damping of the analyzed signal before 1880. After 1880, the strength of the signal is more consistent over time. ERSST is suitable for long-term global and basin-wide studies, and smoothed local and short-term variations are used in the dataset. The NOAA Global Surface Temperature (NOAAGlobalTemp) (formerly known as the Merged Land-Ocean Surface Temperature dataset) product uses ERSST as input along with land surface air temperature data from the Global Historical Climatology Network-Monthly dataset.

Data Access

To receive email notifications for ERSST updates, please visit the ERSST Data Optional Registration page. For information about the data status, changes to processes, and corrections, visit the ERSST status page.


The following publications describe the processes and procedures for each version of the ERSST dataset.


Smith, T.M., and R.W. Reynolds, 2003: Extended reconstruction of global sea surface temperatures based on COADS data (1854–1997). Journal of Climate, 16, 1495–1510. doi:10.1175/1520-0442-16.10.1495


Smith, T.M., and R.W. Reynolds, 2004: Improved extended reconstruction of SST (1854–1997). Journal of Climate, 17, 2466–2477. doi:10.1175/1520-0442(2004)017<2466:IEROS>2.0.CO;2


Smith, T.M., R.W. Reynolds, T.C. Peterson, and J. Lawrimore, 2008: Improvements to NOAA's historical merged land–ocean temperature analysis (1880–2006). Journal of Climate, 21, 2283–2296. doi:10.1175/2007JCLI2100.1

Xue, Y., T.M. Smith, and R.W. Reynolds, 2003: Interdecadal changes of 30-Yr SST normals during 1871–2000. Journal of Climate, 16, 1601–1612. doi:10.1175/1520-0442-16.10.1601


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, 2014: Extended Reconstructed Sea Surface Temperature version 4 (ERSST.v4): Part I. Upgrades and intercomparisons. Journal of Climate, in press, 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, 2014: Extended Reconstructed Sea Surface Temperature version 4 (ERSST.v4): Part II. Parametric and structural uncertainty estimations. Journal of Climate, in press, doi:10.1175/JCLI-D-14-00007.1.

Huang, B., P. Thorne, T. Smith, W. Liu, J. Lawrimore, V. Banzon, H. Zhang, T. Peterson, and M. Menne, 2015: Further Exploring and Quantifying Uncertainties for Extended Reconstructed Sea Surface Temperature (ERSST) Version 4 (v4). Journal of Climate, in press, doi:10.1175/JCLI-D-15-0430.1.

Contact Information

Boyin Huang

Tom Smith