Turbulent Oscillator: Intrinsic Eddy-Driven Decadal Variability of the Ocean

We put forward the CENTRAL HYPOTHESIS that significant fraction of the observed oceanic variability is intrinsic, that is, driven by the internal dynamics of the ocean rather than by variations of the external forcings.
Some of this variability is likely to be explained in terms of the transient linear modes of the climatological mean circulation, but most of it --- and this is our SECOND HYPOTHESIS --- is likely to be driven and controlled by the transient mesoscale eddies that constitute synoptic variability of the ocean and strongly interact with the large-scale circulation.

The RESEARCH STRATEGY of this Project consists of several steps.
First, we will employ a cutting-edge, idealized numerical model on the UK's national supercomputer HECToR and compute a set of pioneering solutions with explicitly and very well resolved eddies and with explicitly simulated large-scale low-frequency variability.
All solutions will be computed in a systematic way, from physically more simple to more comprehensive, and the focus of the proposed modelling will be on the dynamical realism of the eddies and on the underlying fundamental physical processes.
Our preliminary results demonstrate presence of the robust and significant, intrinsic large-scale low-frequency variability that interact with and is driven by the transient mesoscale eddies.
Second, all solutions will be systematically analysed, and the outcome of this analysis will provide the basis for building a theory.
At this point we will be guided, perhaps only initially, by the existing theoretical ideas.

A very useful and efficient NETWORK OF COLLABORATIONS will connect this Project with the research groups engaged in observations, modelling, and understanding of the oceanic large-scale low-frequency variability and the underlying eddy effects.

The INTELLECTUAL MERIT of this Project is in addressing poorly understood intrinsic variability of the ocean and the corresponding roles of the mesoscale eddies.

The BROADER IMPACT is in terms of understanding the global climate variability, with the ultimate goal of acheiving more accurate predictions of the global climate change.

The BROADER CONTEXT is that the underlying nonlinear mechanisms are likely to be pertinent to other parts of the global ocean.

The proposed work will be beneficial for several communities:

Climate modellers will benefit because of the better understanding of how internal dynamics of the midlatitude ocean can contribute to the decadal climate variability.

Ocean observationalists will benefit because they will be guided on what are the key features and properties of the large-scale low-frequency variability and the eddy activity of the midlatitude ocean that need to be accurately estimated.

Ocean modelleres who work with comprehensive general circulation models will benefit by knowing what exactly is missing in non-eddy-resolving or partially eddy-resolving ocean models; the proposed work will also provide some guidance on how to ameliorate the problems associated with underresolving the eddies.

Theoreticians will benefit, because the issue of intrinsic large-scale low-frequency variability in various parts of the ocean is a very fundamental one.

As a result of the proposed work, some ideas and paradigms can be potentially sorted out or overhauled.