Oceanic fluxes of mass, heat, and freshwater : a global estimate and perspective

• Main Author: Macdonald, Alison M.
• Format: Thesis
• Language: English
• Published: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution 1995
• Subjects: Ocean circulation; Atmospheric circulation; Ocean-atmosphere interaction; Thomas G. Thompson (Ship) Cruise; Moana Wave (Ship) Cruise; Atlantis II (Ship : 1963-) Cruise AII109; Atlantis II (Ship : 1963-) Cruise AII93; Charles Darwin (Ship) Cruise; Oceanus (Ship : 1975-) Cruise OC133; Oceanus (Ship : 1975-) Cruise OC338; Knorr (Ship : 1970-) Cruise; Melville (Ship) Cruise; Antarctic; Southern Ocean; The Antarctic; Pacific; Indian; Antarc*
• Online Access: https://hdl.handle.net/1912/5620

Submitted 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 1995 Data 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 ...