GISS Surface Temperature Analysis

Updates to Analysis, ERSST v5 vs. v4

On August 15, 2017, GISS switched from NOAA/NCDC's Extended Reconstructed Sea Surface Temperature (ERSST) dataset version 4 to version 5 in their temperature analysis. According to NOAA's ERRST v5 webpage:

"The newest version of ERSST, version 5, uses new data sets from ICOADS Release 3.0 (Sea Surface Temperatures) SST; SST comes from Argo floats above 5 meters, Hadley Centre Ice-SST version 2 (HadISST2) ice concentration. ERSSTv5 has improved SST spatial and temporal variability by (a) reducing spatial filtering in training the reconstruction functions Empirical Orthogonal Teleconnections (EOTs), (b) removing high-latitude damping in EOTs, and (c) adding 10 more EOTs in the Arctic. ERSSTv5 improved absolute SST by switching from using Nighttime Marine Air Temperature (NMAT) as a reference to buoy-SST as a reference in correcting ship SST biases. Scientists have further improved ERSSTv5 by using unadjusted First-Guess instead of adjusted First-Guess."

The two versions are compared in the graphs and maps below.


Side-by-side comparison of line plots of global temperature using ERSST v4 vs v5 Side-by-side comparison of line plots of global temperature using ERSST v4 vs v5

Comparison of ERSST v4 and v5 in the annual mean and 5-year lowess smooth global land-ocean temperatures. (2017-08-15)
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The difference in monthly mean global land-ocean temperature using ERSST v5 and v4. (2017-08-15)
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The difference in annual mean global land-ocean temperature using ERSST v5 and v4. (2017-08-15)
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Global maps of 2011-2016 comparing use of ERSST 4 vs 5 data

Comparison of last 5 year means. (2017-08-15)
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Global maps of temperature trends comparing use of ERSST v4 vs v5 data

Comparison of long-term changes. (2017-08-15)
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Global 2017 monthly mean anomaly maps comparing use of ERSST v4 vs v5 data

Comparison of some 2017 monthly mean anomalies. (2017-08-15)
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