GISS Surface Temperature Analysis

Updates to Analysis, ERSST v4 vs. v3b

On July 15, 2015, GISS switched from NOAA/NCDC's Extended Reconstructed Sea Surface Temperature (ERSST) dataset version 3b to version 4 in their temperature analysis. According to NOAA's ERRST v4 webpage:

"Major improvements include updated and substantially more complete input data from the ICOADS Release 2.5, revised Empirical Orthogonal Teleconnections (EOTs) and EOT acceptance criterion, updated sea surface temperature (SST) quality control procedures, revised SST anomaly (SSTA) evaluation methods, revised low-frequency data filing in data sparse regions using nearby available observations, updated bias adjustments of ship SSTs using Hadley Nighttime Marine Air Temperature version 2 (HadNMAT2), and buoy SST bias adjustments not previously made in v3b."

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

Note: The graphics on this webpage were updated Jul 18, 2015, following discovery of a bug in our original handling of the ERSSTv4 data. See note on Updates to Analysis for this date.


Comparison of ERSST v3b and v4 in the annual mean and 5-year running mean global land-ocean temperatures. (2015-07-18)
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The difference in annual mean and 5-year mean global land-ocean temperature using ERSST v4 and v3b. (2015-07-18)
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The difference in monthly mean global land-ocean temperature using ERSST v4 and v3b. (2015-07-18)
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Comparison of last 5 year means. (2015-07-18, 2015-10-08)
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(An update was made 2015-10-08 to this figure due to discrepancy between small and large graphics caused by versioning issue.)


Comparison of long-term changes. (2015-07-18)
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Comparison of two extreme years: 1938 when v4 < v3b and 1944 when v4 >> v3b. (2015-07-18)
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