Student Projects
The University of New South Wales' School Mathematics and Statistics is number one in Australia and offers a range of opportunities for graduate level research. I am also an associate investigator on the Australian Research Council Climate System Science Centre of Excellence which offers a range of opportunities for students and the potential for co-supervision across UNSW and Australia. I also have close collaborations in Europe and North America should you be interested in a project with formal or informal collaboration across continents.
Project 1: Quantifying Global Water Cycle Change using Ocean Observations
Global rates of rainfall and evaporation are amplifying rapidly as a consequence of global warming. Recent studies have suggested that this 'water cycle' could be amplifying faster than global climate models had predicted. More accurate quantification of water cycle change and its causes is urgently needed. Changes in the water cycle leave an imprint on the ocean by changing ocean salinity. The candidate will quantify water cycle change based on new observations of ocean salinity and using novel methods developed by the supervisory team. These findings will help improve predictions of water cycle change that are relied upon by society.
This projects is funded through a new lucrative UNSW Scientia PhD scheme and offers 4-years of funding with a tax-free stipend of $40K/annum and up to $10K/annum towards research costs. The scheme is open to all nationalities. For eligibility for the Scientia PhD, applicants should contact us and complete a short online questionnaire (http://www.2025.unsw.edu.au/apply/) before the 21st of July 2017.
The following projects are just starting points and can be adapted to an individual student's interests and to fit an summer research, Honours, Masters or PhD level program. See my publications list for other ideas and please don't hesitate to contact me directly (j.zika(at)unsw.edu.au).
Project 2: Linking the seasonal cycle of ocean water masses to transient climate change
In boreal winter the North Atlantic and Pacific Oceans become cold, dense and turbulent. Oxygen, carbon and other substances are drawn out of the atmosphere and ventilated into the deep ocean. In boreal summer, as the surface layers in the north warm, cooling and ventilation begins in the southern hemisphere in earnest.
The process of seasonal ventilation dictates the ocean’s role in climate - both present and future. Only in the last decade has a systematic understanding of seasonal ventilation become possible due to the presence of thousands of autonomous buoys (ARGO) and satellites measuring upper ocean temperature and salinity. Likewise never has the need to quantify it been more pressing.
This project will combine the latest observations to generate a quantitative picture of the formation, ventilation and destruction of cold dense water masses in both hemispheres. A key novelty of this project will be the use the water-mass transformation framework. Using this framework variability in water mass properties is attributed to surface heating and cooling, evaporation and precipitation, mixing and energetic drivers such as wind forcing.
Project 3: Asymmetry of the ocean’s thermohaline circulation
The ocean is highly turbulent. Pathways of free-floating buoys are chaotic and circulation patterns are dominated by mesoscale eddies – the ocean’s equivalent to atmospheric storms. The ocean is at the same time organised.
Substances injected into the ocean follow broad and distinct routes near the sea surface from the Pacific to the Atlantic Ocean. As a result the North Pacific and North Atlantic Ocean’s are in marked contrast. The Pacific is cold and fresh and the Atlantic is warm and salty. Known as the thermohaline circulation, this helps maintain Europe’s relatively mild climate.
This project will explore the link between the asymmetry in northern hemisphere climates, the thermohaline circulation and the atmospheric forcing which sets the eventual temperature and salinity of sea-water. The project will pivot on the hypothesis that, by accident of geography and the position of southern hemisphere winds, warm saline water preferentially flows into the Atlantic. Moreover these effects will dictate the stability of the thermohaline circulation and European climate over coming centuries.
Project 4: Distilling the ocean’s role in climate using thermodynamic diagrams
Understanding how much and to what depth heat will be pumped into the ocean is critical to predict future surface temperature and sea-level rise.
This study will investigate vertical heat transport in the ocean using novel thermodynamic diagrams. Using such diagrams, which have origins in classical thermodynamics, one can relate the circulation to surface heating and cooling processes and mixing.
Solutions for such circulations are tractable both from analytical, simple numerical and observational points of view. The student will consider both idealised cases and make use of the most recent observations. These will be combined with constraints based on theories of ocean mixing and energetics to generate estimates of the deep overturning circulation and its role in transient climate change.
