Consistent near-surface ocean warming since 1900 in two largely independent observing networks

We compare historical global temperature time series, based on bias-adjusted sea-surface temperatures with independent temperature time series, for the upper 20 meter layer of the ocean based on the latest update of an historical hydrographic profile data set. Despite the two underlying data sets being different in number of data points, instrumentation and applied adjustments, both of the time series are consistent in showing an overall warming since 1900. We also extend records of temperature change in the upper 400 m back to 1900. Noting that the geographic coverage is limited prior to 1950, the temperature change in the 0-400 m layer is characterized by two periods of temperature increase between 1900 and 1940-45 and between 1970 and 2003, separated by a period of little change. Citation: Gouretski, V., J. Kennedy, T. Boyer, and A. Kohl (2012), Consistent near-surface ocean warming since 1900 in two largely independent observing networks, Geophys. Res. Lett., 39, L19606, doi:10.1029/2012GL052975.