A high-resolution global sea surface temperature climatology for the 1961-90 base period

In an earlier study (Reynolds and Smith), a monthly 1 degrees SST climatology was produced for the 1950-79 base period. This climatology was constructed from two intermediate climatologies: a 2 degrees SST climatology developed from in situ data for the period 1950-79, and a 1 degrees SST climatology for the period 1982-93 derived from an optimum interpolation SST analysis that uses in situ and satellite data. Since then a new 2 degrees spatial resolution near-global SST analysis has been developed which can produce a similar high-resolution climatology for any base period within the analysis period (1950-92). In this note the procedure is utilized to change the base period to 1961-90, which is the climatological base period suggested by the World Meteorological Organization. The method is nearly identical to that used in the earlier study except for the formation of the 2 degrees climatology from new analyses. The results show that the change in the climatology is generally small with absolute differences usually less than 0.2 degrees C. As with the earlier climatology, in regions where insufficient in situ observations are available prior to 1982 there is no adjustment. In those regions, which include the Southern Ocean, the climatology base period is 1982-96.