Coastal and Regional Oceanography Lab

Towards an Integrated Dynamical Understanding of Coastal Marine Systems

Opportunities for study

We welcome interested students and researchers to make enquiries and to join our team.

Postgraduate research projects including Masters and Doctoral projects are often available, and grants/scholarships may be applicable.

Publicised opportunities are listed below. These may be undertaken as Vacation Honours projects or may even be a suitable starting point for a Masters or Doctoral Thesis.

Prospective students should contact one of the listed superviors on our team page and you can find more information about studying at UNSW here.

Investigating transport pathways in the ocean with Lagrangian Coherent Structures

Supervisors: Dr Matthew Archer, Dr Shane Keating and Dr Moninya Roughan

In this project, you will work with measurements from high frequency (HF) radar along the NSW coastline to locate Lagrangian coherent structures (LCS) hidden in the ocean surface currents. The LCSs obtained from HF radar measurements provide a unique way to visualize the evolving structure of dynamic ocean features such as fronts, filaments and eddies in the Tasman Sea. These structures govern the transport pathways of particles in the ocean (such as oil, or fish larvae). You will investigate how different flow regimes affect particle dispersion at the ocean surface. This project will work with HF radar measurements of ocean current velocity, together with satellite imagery of sea surface temperature and chlorophyll-a.

There will be opportunities for oceanographic field work if desired. You will need a basic knowledge of mathematics, and experience in a programming language such as Matlab or Python is desirable.

 

Figure: Ocean Currents from HF Radar in the East Australian Current; Langrangian Coherent Structure.

What are the main factors driving biological variability on the continental shelf?

Supervisors: Dr Amandine Schaeffer and A/ Prof Moninya Roughan

Fluorescence measurements (a proxy for chlorophyll) obtained from repeated ocean gliders deployments and oceanographic moorings on the continental shelf of Australia will be analyzed and related to the physical oceanographic conditions (temperature, salinity) and forcings (wind, current, eddy encroachment).

Required skills: Some knowledge of Physical oceanography and statistics; Matlab or Python programming.

Figure: Shows wind stress, Chlorophyll, Dissolved oxygen (20m below the surface), temperature and along shore current speed (through the water column) at the 100m isobaths off Sydney. What drives the spikes in Chlorohpyll from day 10 to day 20?

 

Diagnosing submesoscale ocean eddies

Supervisors: Dr Shane Keating and A/ Prof Moninya Roughan

The recent improvements in ocean observing technologiy has allowed us to unveil the intricacies of ocean circulation at submesoscales. The student will use a combination of ocean model output and observational data from coastal radar, moorings, and satellite observations to quantify the properties of submesoscale eddies, both cyclonic and anticyclonic, including lifespan, size, and shedding frequencies.

 

Initial condition adjustments to improve numerical model predictions of the East Australian Current circulation

Supervisors: Dr. Colette Kerry and A/ Prof. Moninya Roughan

The East Australian Current (EAC) transports warm water from the tropics southward along the east coast of Australia. The current becomes unstable and forms a series of mesoscale eddies, particularly between 31-33S where it strengthens and separates from the coast before turning eastward, forming the eddy-rich Tasman Front. The EAC is one of the most dynamic oceanic regions on the planet making its circulation very difficult to predict.

Numerical ocean models use an initial estimate of the ocean state, and step discretised equations of motion forward in time given applied atmospheric forcing, to provide an estimate of the ocean state over time. Errors in ocean modelling can arise from uncertainties in initial conditions, model forcings, and imperfect representations of the ocean dynamics by the discretised physical equations used.

The mesoscale ocean circulation is highly sensitive to the initial state and data assimilation techniques are used to adjust the initial conditions such that the resulting model estimate provides an optimum representation of available ocean observations. We have combined an array of ocean observations (e.g satellite derived SSH and SST, profiling floats, in situ moorings, ocean gliders) with a numerical model using data assimilation to generate an estimate of the 3-dimensional ocean state over a 2-year period in the EAC region. This estimate applies corrections to the ocean model initial conditions every 4 days so as to provide an optimised representation of the true ocean state as measured by the observations over each 4-day window.

The student will analyse the adjustments made to the initial conditions (sea surface height, ocean temperature and current velocities) to understand where the corrections are being made. Biases, variability and Empirical Orthogonal Function analysis, showing the dominant modes of variability, of the initial condition adjustments will provide insight into inherent errors in the model configuration or forcing.

Skills in Matlab or other data analysis programs are desirable.

Figure: Snapshot of Sea Surface Height from the combined model-observations ocean state estimate (currents move around the high and low regions, analogous to winds around high and low atmospheric pressure systems)

 

Using a momentum balance to understand key drivers in the East Australian Current circulation from a numerical model combined with real ocean observations

Supervisors: Dr. Colette Kerry and A/ Prof. Moninya Roughan

The East Australian Current (EAC) transports warm water from the tropics southward along the east coast of Australia. The current strengthens and separates from the coast between 31-33S before turning eastward, forming the Tasman Front. This acceleration and separation off of central NSW results in episodic upwelling of nutrient-rich slope water onto the continental shelf and the formation of large warm- and cold-core eddies. The current has a significant impact on the weather and climate of the most densely populated region of the country and its associated coastal upwelling and eddy entrainment is a major driver of biological productivity in an otherwise nutrient-devoid system.

By combining an array of ocean observations (e.g satellite derived SSH and SST, profiling floats, in situ moorings, ocean gliders) with a numerical model using data assimilation techniques, we have generated an estimate of the 3-dimensional ocean state over a 2-year period. This estimate applies corrections to the dynamical ocean model so as to provide an optimised representation of the true ocean state as measured by the observations. The student will choose a selection of interesting ‘circulation events’ such as coastal upwelling, separation of the EAC from the coast, and eddy formation and compute the breakdown of terms in the momentum balance to understand the physical drivers of these circulation features.

Skills in Matlab or other data analysis programs are desirable.

Figure: Snapshot of Sea Surface Temperature from the combined model-observations ocean state estimate

 

The meso-scale eddy field along the southeastern Australian coast under a climate change scenario.

Supervisors: Dr. Paulina Cetina-Heredia Dr. Amandine Schaeffer Dr. Moninya Roughan

Meso-scale eddies are often formed in the region where the East Australian Current (EAC) separates from the continent. These eddies influence the circulation in the region having an impact in productivity and the transport of larvae. Recent studies have shown that the transport inside meso-scale eddies has increased in recent decades. This projects aims to investigate differences between the contemporary and future meso-scale eddy field using outputs from the Ocean Forecast Australian Model (OFAM).The spin parameter, a lagrangian vorticity, and an algorithm based on sea surface heights will be used as diagnostics to quantify the amount of eddies (cyclonic and anticyclonic) in the contemporary and future scenarios. In addition, the life-span and spatial extent of such eddies will also be computed. Finally, implications of meso-scale eddy field changes on larval transport and productivity should be discussed. If you are interested in oceanography this is a good project to choose; it is multidisciplinary in the sense that mathematical tools are used to explore the ocean's circulation which in turn influences the marine ecosystem. The student needs to have basic knowledge of mathematics and expertise in programming is desirable since MatLab will be used.

Figure. Snapshot of velocity magnitude (color-scale) and particles 28 days after release at Coffs Harbour (white dots) depicting the presence of meso-scale eddies along the southeastern Australian coast.

 

Archived Projects

These projects are no longer available but may be useful for reference as to the kind of research we do.

You are welcome to contact us with your own research project ideas.

(archived) Characteristics of the East Australian Current from HF radar observations.

Supervisors: Dr Amandine Schaeffer, Dr Paulina Cetina-Heredia and Dr Moninya Roughan.

The East Australian Current (EAC) is the major feature of the ocean circulation along south-eastern Australia, influencing the water temperature, phytoplankton to fish distribution and regional climate. In a effort to characterise the EAC, more than 1 year of observations of surface currents from HF Radars will be investigated. Information on the EAC speed, distance from the coast, width and seasonality can be extracted. Moreover, the main modes of variability, occurrence of eddies and the relationship with wind and water temperature will be investigated. No background in oceanography is needed, but data analysis, programming and statistics skills are desired. Matlab will be used..

 

Figure shows monthly surface current vectors (arrows), speed (colour) and variance ellipses from HF radar observations in June 2012. The coastline and 100-, 200-, 1000-, and 2000-m depth contours are shown.