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Contact details

Group: 
Marine Physics and Ocean Climate
Site: 
Liverpool
Email: 
cwi at noc.ac.uk

Profile

Biography

Eddies in Sea Ice: Ocean colour from Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite on October 17, 2012, near Denmark Strait.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Research interests

Observing, understanding and predicting phenomena and their connecting processes in the Earth system, for the benefit of society and the environment, is the broadest description of my research interests.      

At the heart of what fascinates me scientifically, is the complexity and often surprising nature of nonlinear dynamics (climate dynamics, geophysical fluid dynamics) and the nonlinear connections between dynamical processes which mean that small, fast changes can influence much larger, slower changes and vice-versa.   An example of such a phenomenon is a "freak wave", where three apparently typical surface waves may interact nonlinearly and if their frequencies and wavelengths combine in a certain way, they may interact to produce rapidly-amplifying, resonant wave.        Other nonlinear effects include the process of ocean mesoscale eddies (tens of kilometers in diameter; evolving over days to weeks) interacting with ocean currents like the Gulf Stream.  First, the eddies obey linear dynamical theory, growing in size and speed by extracting energy from the current, then as the eddies are swept along by the current, their shape is deformed and there is a nonlinear interaction, where the eddies feed energy and momentum back into the current, accelerating it and making the current become more narrow and filamented.       Similarly, in models of the full climate system, often expressed abstractly in terms of dynamical systems theory, there can be periods where the rate of change of the properties of the system remains explainable by linear theory (simple equations, easy to predict the future state), but other periods where the dynamics are more nonlinear and even chaotic, and where climate may change rapidly and less predictably.    Using these types of understanding for the benefit of society and the environment means defining measures of the state of the climate system, or "climate metrics", which are important in terms of their information content, their potential predictability and how they resonate with the people who care about their impacts.

My focus is to seek the most simple, yet realistic (close to real-world observations) description of nonlinear dynamics, predictability and impacts of sea-level, ocean eddies and climate, suited to particular climate metrics (equivalently, climate questions).

To do this I use observations, theory, modelling (theoretical and computational) and data analysis methods.

 

My specialist interests are:

  • Ocean transport and mixing - both in terms of the kinematics of flow deformation and the generation of coherent flow structures (eddies/vortices/saddles) and the dynamics (how these structures evolve subject to the physical equations of motion for the fluid).

 

  • The representation of eddies in the ocean component of climate models - eddy parameterisation, the effect of eddies on larger and smaller scales and therefore on long-term climate predictability and short-term forecasting.

 

  • Representation of the climate as a dynamical system - a commonly used layer of abstraction that is helpful for understanding complexity, predictability, chaos and the role of nonlinear dynamics (usually involving waves, turbulence or eddies).

 

  • Sea-level science - understanding and predicting sea-level change, especially for regional and local-scale societal and environmental impacts.  This involves a range of collaborative approaches, since sea-level is the sum of a large number of dynamical and thermodynamical processes, and relies on combining several observing systems in different reference frames with tailored modelling solutions for the best predictions. 

 

 

Research profile and statistics

ORCID profile: (click here)

Google Scholar: (click here)

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