Antarctic climate: ocean fluxes and variability

The Southern Ocean plays a major role in the global overturning circulation, providing<br/>an important route for the return flow of deep water subducted in the North Atlantic.<br/>The World Ocean Circulation Experiment (WOCE) provided an unprecedented picture<br/>of the state of the world’s oceans and set new standards for high quality in-situ<br/>hydrographic data. This study combines the existing WOCE data set with new<br/>hydrographic sections, and output from global and regional ocean models to examine<br/>the mean state of the Southern Ocean circulation and the balance of fluxes around the<br/>Antarctic Circumpolar current.<br/><br/>A historical data set in the region of Drake Passage is examined to study the large-scale<br/>water mass variability between 1926-2005. The water mass properties of the Lower<br/>Circumpolar Deep Water is constant within error bounds throughout the data set. A<br/>warming and freshening signal in the surface waters from 1997-2005 to the north of the<br/>Sub-Antarctic Front along SR01b is also presented.<br/><br/>The major part of this work is based around an inverse study of the Southern Ocean that<br/>combines the WOCE data-set with contemporary sections, and other forcing fields to<br/>examine the balance of fluxes throughout the Southern Ocean. The study examines the<br/>effect of different parameterisations of the dianeutral mixing in the Southern Ocean, in<br/>light of the differing views of localised deep turbulent mixing from observations, and an<br/>adiabatic ocean interior from residual mean studies, The freshwater balance in the<br/>model is presented and its implications on the water mass formation and transformation<br/>of the upper and lower cells of the overturning circulation is discussed in detail.

Name dc:type.qualificationname

Ph.D.

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Southampton

Year dc:date.issued

2008

Author dc:creator

• Williams, Adam Peter

Advisors dc:contributor.advisor

• Bacon, Sheldon
• Rohling, Eelco