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 a NOAA page
"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 version 5 is compared to previous versions in some graphs and maps below.
Comparison of the 12-month running means of the global surface temperature using ERSST v5 to v3b and v4. Figure in
12-month and 132-month running mean global surface temperature using ERSST v4 and v5. Figure in
The difference in the monthly mean global surface temperature using ERSST v5 and v4. Figure in
The difference in the monthly mean global surface temperature using ERSST v5 and v4 for 2000-present. Figure in
Comparison of longterm changes. Figure in
Comparison of the 2011-2016 mean temperature. Figure in
Comparison of three months with large differences,