Publication Date:
2008-02-10
Description:
The possibility that the oceanic general circulation is undergoing changes as part, or the cause, of major climate shifts is being intensely discussed, with some published results relying on data from moorings spanning the North Atlantic Ocean. The circulation is, however, extremely noisy. Here, I use existing estimates of the frequency and wavenumber content of geostrophic eddies in the ocean to show that variations in ocean-wide integrated transport must appear even in the absence of a true long-term trend. Expected fluctuations exceed ±20×109 kg s1 (or ±20× 106m3s1) and exhibit multi-year timescales. Existing knowledge of the eddy field allows predictions of observed variability and produces lower bounds on the (multi-decadal) timescale required to detect true trends of a large magnitude. Detecting and understanding the effect of climate change on the ocean circulation requires observations in three dimensions over long periods of time. © 2008 Nature Publishing Group.
Print ISSN:
1752-0894
Electronic ISSN:
1752-0908
Topics:
Geosciences
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