| Summary: | Typescript (photocopy) Authors name on cover: Paul Mark Barker Thesis (PhD) -- University of Melbourne, Faculty of Science, 2004 Includes bibliographical references (leaves 333-344) The thermohaline conveyor belt circulation does not include the circulation of the intermediate waters. The South Australian Basin (SAB) plays a key role in the circulation of these intermediate waters, which reside below the permanent thermocline, complementing the thermohaline conveyor belt circulation. We show that the circulation and mixing processes are the same for the mode, intermediate and upper deep water. The westward Tasman outflow and the northward advecting Southern Ocean water interact, forming a �smooth � water mass. This results in the formation of Tasmanian Subantarctic Mode Water (TSAMW), Tasmanian Intermediate Water (TIW) and there also appears to be a smooth type of Upper Circumpolar Deep Water (UCDW). The mixing is enhanced by a saddlepoint in the streamflow, whose position is determined by the circulation of the two source waters. The new water masses spread westward, due to the gyral circulation, which results in homogeneous hydrology fields throughout the SAB. In particular, the TSAMW propagates as an unstable water mass, identified in the water column by a double retroflection in the ? - ?t relationship. Comparison of the hydrology between 1970 and 1994 reveals that on neutral surfaces the TSAMW has both cooled (1�C) and freshened (0.25 psu), which is a consequence of a warmer surface layer. A comparison of the historical and more recent TS diagrams with World Ocean Atlas (WOA98) suggests that the top of water column has shifted to the west by about 8�. A numerical simulation indicates that this translation can be reproduced within this period through an (~ 50%) increase in the transport of the Tasman outflow. The circulation of the SAB consists of an anticyclonic gyre, driven by a positive wind stress curl, combined with the westward Tasman outflow. Between about 1958 and 1997 over the eastern ...
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