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dc.contributor.authorMacdonald, Alison M.  Concept link
dc.date.accessioned2012-12-13T20:32:04Z
dc.date.available2012-12-13T20:32:04Z
dc.date.issued1995-08
dc.identifier.urihttps://hdl.handle.net/1912/5620
dc.descriptionSubmitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution August 1995en_US
dc.description.abstractData from fifteen globally distributed, modern, high resolution, hydrographic oceanic transects are combined in an inverse calculation using large scale box models. The models provide estimates of the global meridional heat and freshwater budgets and are used to examine the sensitivity of the global circulation, both inter and intra-basin exchange rates, to a variety of external constraints provided by estimates of Ekman, boundary current and throughflow transports. A solution is found which is consistent with both the model physics and the global data set, despite a twenty five year time span and a lack of seasonal consistency among the data. The overall pattern of the global circulation suggested by the models is similar to that proposed in previously published local studies and regional reviews. However, significant qualitative and quantitative differences exist. These differences are due both to the model definition and to the global nature of the data set. The picture of the global circulation which emerges from the models IS a complex, turbulent flow. When integrated across ocean basins not one, but two major cells emerge. The first connects an Atlantic overturning cell (estimated at 18± 4x 109 kg s- 1) to the Southern Ocean where the Antarctic Circumpolar Current carries lower deep waters to the Indian and Pacific basins where they are converted to upper deep and intermediate waters before returning to the Atlantic. The second cell connects the Pacific and Indian Basins to the north and south of Australia. In t his cell deep waters pass into the Pacific and return within the Indian Basin as intermediate waters after passing through the Indonesian Passages. The two cells are found to be independent of one another, i.e. within the models, the Indonesian Passages do not represent a significant element in a net global circulation. While there is ample evidence of westward flow around the southern tip of South Africa which would support a "warm" water path scenario, the variability of flow in this region, rich with eddies makes hydrography a poor estimator of the relative strengths of the controversial "warm" and "cold" water paths. All existing estimates of Indonesian Passage throughflow, including the smallest (O x 106 m3 s-1) and the largest (20 x 106 m3 s-1), are consistent with the model constraints. When the Pacific- Indian throughflow is not constrained, the model produces an estimate of 11 ± 14x 109 kg s-1. The model heat flux estimates are both significantly different from zero and quite robust to changes in initial assumptions, with the exception of the choice of wind field. Although in this work it was not possible to compute freshwater fluxes which were significantly different from zero, future inclusion of salinity anomaly constraints along with terms describing vertical diffusion may yet make it possible to compute significant freshwater :flux estimates from hydrography.en_US
dc.description.sponsorshipThis research was partially funded by a NASA Global Change Fellowship and was also supported by NASA under contract NAGW-1048 and NSF under contract OCE-9205942.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherMassachusetts Institute of Technology and Woods Hole Oceanographic Institutionen_US
dc.relation.ispartofseriesWHOI Thesesen_US
dc.subjectOcean circulationen_US
dc.subjectAtmospheric circulationen_US
dc.subjectOcean-atmosphere interactionen_US
dc.subjectThomas G. Thompson (Ship) Cruiseen_US
dc.subjectMoana Wave (Ship) Cruiseen_US
dc.subjectAtlantis II (Ship : 1963-) Cruise AII109en_US
dc.subjectAtlantis II (Ship : 1963-) Cruise AII93en_US
dc.subjectCharles Darwin (Ship) Cruiseen_US
dc.subjectOceanus (Ship : 1975-) Cruise OC133en_US
dc.subjectOceanus (Ship : 1975-) Cruise OC338en_US
dc.subjectKnorr (Ship : 1970-) Cruiseen_US
dc.subjectMelville (Ship) Cruiseen_US
dc.titleOceanic fluxes of mass, heat, and freshwater : a global estimate and perspectiveen_US
dc.typeThesisen_US
dc.identifier.doi10.1575/1912/5620


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