The Global Zonally Integrated Ocean Circulation, 1992–2006: Seasonal and Decadal Variability
Name
Wunsch-2009-The global zonally i.pdf
Size
2.98 MB
Format
Adobe PDF
Checksum (MD5)
bcf128273e5c3bbb162e9a6f9297a5f4
Author(s)
Heimbach, Patrick
Wunsch, Carl Isaac
Date Issued
August 2009
Journal
Journal of Physical Oceanography
Publisher
American Meteorological Society
Citation
Wunsch, Carl, and Patrick Heimbach. “The Global Zonally Integrated Ocean Circulation, 1992–2006: Seasonal and Decadal Variability.” Journal of Physical Oceanography (2009): 351-368. ©2009 American Meteorological Society
Version
Final published version
Abstract
The zonally integrated meridional and vertical velocities as well as the enthalpy transports and fluxes in a least squares adjusted general circulation model are used to estimate the top-to-bottom oceanic meridional overturning circulation (MOC) and its variability from 1992 to 2006. A variety of simple theories all produce time scales suggesting that the mid- and high-latitude oceans should respond to atmospheric driving only over several decades. In practice, little change is seen in the MOC and associated heat transport except very close to the sea surface, at depth near the equator, and in parts of the Southern Ocean. Variability in meridional transports in both volume and enthalpy is dominated by the annual cycle and secondarily by the semiannual cycle, particularly in the Southern Ocean. On time scales longer than a year, the solution exhibits small trends with complicated global spatial patterns. Apart from a net uptake of heat from the atmosphere (forced by the NCEP–NCAR reanalysis, which produces net ocean heating), the origins of the meridional transport trends are not distinguishable and are likely a combination of model disequilibrium, shifts in the observing system, other trends (real or artificial) in the meteorological fields, and/or true oceanic secularities. None of the results, however, supports an inference of oceanic circulation shifts taking the system out of the range in which changes are more than small perturbations. That the oceanic observations do not conflict with an apparent excess heat uptake from the atmosphere implies a continued undersampling of the global ocean, even in the upper layers.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
http://dx.doi.org/10.1175/2008JPO4012.1
