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How much is the ocean really warming?
Author(s) -
Gouretski Viktor,
Koltermann Klaus Peter
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl027834
Subject(s) - bathythermograph , ocean heat content , hydrography , effects of global warming on oceans , environmental science , climatology , oceanography , global warming , climate change , term (time) , sampling (signal processing) , sea surface temperature , geology , computer science , physics , filter (signal processing) , quantum mechanics , computer vision
We use a global hydrographic dataset to study the effect of instrument related biases on the estimates of long‐term temperature changes in the global ocean since the 1950s. The largest discrepancies are found between the expendable bathythermographs (XBT) and bottle and CTD data, with XBT temperatures being positively biased by 0.2–0.4°C on average. Since the XBT data are the largest proportion of the dataset, this bias results in a significant World Ocean warming artefact when time periods before and after introduction of XBT are compared. Using bias‐corrected XBT data we argue reduces the ocean heat content change since the 1950s by a factor of 0.62. Our estimate of the ocean heat content increase (0–3000 m) between 1957–66 and 1987–96 is 12.8·10 22 J. Because of imperfect sampling this estimate has an uncertainty of at least 8·10 22 J