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Extended Reconstructed SST

The Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a global monthly analysis of SST data derived from the International Comprehensive Ocean–Atmosphere Dataset (ICOADS). The dataset can be used for long-term global and basin-wide studies and incorporates smoothed local and short-term variations. The NOAA Global Surface Temperature (NOAA GlobalTemp) product integrates ERSST data with land surface air temperature from the Global Historical Climatology Network-Monthly dataset to create integrated surface temperature analyses.

Contact Information

Product Rep: 
Boyin Huang |

Version 5

Data Sources


  • Improved SST spatial and temporal variability by:
    1. Reducing spatial filtering in training the reconstruction functions Empirical Orthogonal Teleconnections (EOTs)
    2. Removing high-latitude damping in EOTs
    3. Adding 10 more EOTs in the Arctic
  • Improved absolute SST by using buoy-SST as a reference to correct ship biases
  • Updated to unadjusted First Guess from adjusted First Guess

Gridded Data


ERSST Specifications
Spatial Resolution: 2° × 2° horizontal grid with statistically enhanced spatial completeness
Time Frame:  January 1854—Present (anomalies are computed with respect to a 1971— 2000 climatology)
Data Sources:  ICOADS 3.0, which combines SST from Argo floats (above 5 meters), Hadley Centre Ice-SST version 2 (HadISST2) ice concentration (1854-2015), and NCEP ice concentration (2016-present)
Reliability: Data are more reliable after the 1940’s

Note: Data sparsity in early records (before 1880) creates a damping effect that affects the analyzed signal, but its strength and consistency improves over time.


Boyin Huang, Peter W. Thorne, Viva F. Banzon, Tim Boyer, Gennady Chepurin, Jay H. Lawrimore, Matthew J. Menne, Thomas M. Smith, Russell S. Vose, and Huai-Min Zhang (2017): NOAA Extended Reconstructed Sea Surface Temperature (ERSST), Version 5. [indicate subset used]. NOAA National Centers for Environmental Information. doi:10.7289/V5T72FNM [access date].

Previous Versions

Version 4 Data Sources

  • ICOADS 2.5

Version 4 Updates

  • Revised empirical orthogonal teleconnections (EOTs) and EOT acceptance criterion
  • Updated SST quality control procedures
  • Revised SST anomaly (SSTA) evaluation methods
  • Updated bias adjustments of ship SSTs using the Hadley Centre Nighttime Marine Air Temperature dataset version 2 (HadNMAT2)
  • Buoy SST bias adjustment not made in v3b

Version 4 Gridded Data

Version 4 Time Series

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Version 4 Citation

Boyin Huang, Viva F. Banzon, Eric Freeman, Jay Lawrimore, Wei Liu, Thomas C. Peterson, Thomas M. Smith, Peter W. Thorne, Scott D. Woodruff, and Huai-Min Zhang, 2015: Extended Reconstructed Sea Surface Temperature (ERSST), Version 4. [indicate subset used]. NOAA National Centers for Environmental Information. doi:10.7289/V5KD1VVF [access date].

Version 3 Data Sources


Version 3 Updates

Version 3 Gridded Data

Version 3 Citation

Smith, Thomas M., Richard W. Reynolds, Thomas C. Peterson, and Jay Lawrimore (2010): Extended Reconstructed Sea Surface Temperature (ERSST) Monthly Analysis, Version 3b. [indicate subset used]. NOAA National Climatic Data Center. doi:10.7289/V5Z31WJ4 [access date].

ERSST v3b corrected a bias created when satellite data was added to version 3 of the dataset.  SST captured by satellite Advanced Very High Resolution Radiometer (AVHRR) caused a cold bias that changed monthly rankings in v3.

While v3 improved low frequency tuning that reduced the SST anomaly damping before 1930 using the optimized parameters, the addition of satellite SSTs introduced a small residual cold bias (in the order of 0.01°C). The AVHRR is an infrared-based instrument that only works effectively in clear-sky conditions, and cloud contaminated data are often difficult to identify. This contamination leads to a cold SST bias in the retrievals. There were attempts to correct these biases as mentioned in "Improvements to NOAA's Historical Merged Land-Ocean Surface Temperature Analysis (1880–2006)," but the adjustment did not fully compensate for the cold bias. While this small difference did not strongly influence the long-term trend, it was significant enough to change the rankings of the warmest months in the time series. Therefore, use of satellite SST data was discontinued.


  • Huang, B., M. J. Menne, T. Boyer, E. Freeman, B. E. Gleason, J. H. Lawrimore, C. Liu, J. J. Rennie, C. Schreck, F. Sun, R. Vose, C. N. Williams, X. Yin, and H.-M. Zhang, 2020: Uncertainty estimates for sea surface temperature and land surface air temperature in NOAAGlobalTemp version 5. Journal of Climate, 33, 1351-1379, doi: 10.1175/JCLI-D-19-0395.1.
  • Huang, B., C. Liu, G. Ren, H.-M. Zhang, and L. Zhang, 2019: The role of buoy and Argo observations in two SST analyses in the global and tropical Pacific oceans. Journal of Climate, doi:10.1175/JCLI-D-18-0368.1.
  • Huang, B., W. Angel, T. Boyer, L. Cheng, G. Chepurin, E. Freeman, C. Liu, and H.-M. Zhang, 2018: Evaluating SST analyses with independent ocean profile observations. J. Climate, 31, 5015-5030, doi:10.1175/jcli-d-17-0824.1.
  • Huang, B., Peter W. Thorne, et. al, 2017: Extended Reconstructed Sea Surface Temperature version 5 (ERSSTv5), Upgrades, validations, and intercomparisons. Journal of Climate, doi: 10.1175/JCLI-D-16-0836.1.
  • Huang, B., C. Liu, G. Ren, H.-M. Zhang, and L. Zhang, 2018: The role of buoy and Argo observations in two SST analyses in the global and tropical Pacific oceans. Journal of Climate, 32, 2517-2535, doi:10.1175/JCLI-D-18-0368.1.


  • 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, 2014: Extended Reconstructed Sea Surface Temperature version 4 (ERSST.v4): Part I. Upgrades and intercomparisons. Journal of Climate, 28, 911–930, doi:10.1175/JCLI-D-14-00006.1.
  • Liu, W., B. Huang, P.W. Thorne, et. al, 2014: Extended Reconstructed Sea Surface Temperature version 4 (ERSST.v4): Part II. Parametric and structural uncertainty estimations. Journal of Climate, 28, 931–951, doi:10.1175/JCLI-D-14-00007.1.
  • Huang, B., P. Thorne, T. Smith, et. al, 2015: Further Exploring and Quantifying Uncertainties for Extended Reconstructed Sea Surface Temperature (ERSST) Version 4 (v4). Journal of Climate, 29, 3119–3142, doi:10.1175/JCLI-D-15-0430.1.


  • 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.



  • 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.