Problems in the Use of Ship Observations for the Study of Interdecadal Climate Changes

Abstract

Time series of sea surface temperature (SST) and air temperature (AT) for 1870–1969 based an ship observations over the Pacific are examined. The familiar signals of interannual variability in the equatorial and northeast Pacific are evident. Inhomogeneities are found in the interdecadal variation, in agreement with other workers. In particular, SST values in 1920–39 were too low relative to 1949–68 throughout the Pacific. A regional and seasonal analysis of this error reveals a close relationship with SST minus AT, suggesting that a contributory cause could be the cooling of uninsulated buckets. Cloudiness data aim exhibited spatially consistent inhomogeneities during 1920–50.