Extended Reconstructed Sea Surface Temperature (ERSST)

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

• ASCII
• NetCDF

Version 4 Time Series

• ASCII

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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

• ICOADS

Version 3 Updates

• Identical to version 3 (updates described in Improvements to NOAA’s Historical Merged Land–Ocean Surface Temperature Analysis (1880–2006)), but satellite data have been excluded to correct a cold bias.

Version 3 Gridded Data

• ASCII
• NetCDF

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.