Global satellite observations of oceanic eddies

The ocean, like the atmosphere, is turbulent. At large scales this turbulence is nearly two-dimensional, consisting of nonlinear coherent vortices whose velocity field effectively stir and mix things around. These vortices are tens of kilometers in size but are still poorly resolved by the computational grids in global ocean climate models.

We instead have to tell the models about the size and energy of these vortices, or eddies, so that their stirring and mixing capacity can be correctly simulated. This 'parametrization' issue is particularly important at high latitudes, like in the Nordic Seas and Arctic Ocean, where the eddies are very small (compared to the model's grid size).

In this project we will study the global geographic distribution of eddy size and eddy energy from satellite observations of the sea surface. These properties of eddies will be deduced with the help of advanced signal processing methods that involve wavelets (one can think of this as an optimal windowed Fourier transform that gives information about scale and position at the same time).

The aim is to obtain robust estimates of eddy scale and energy and then compare these to existing theoretical models for how ocean eddies behave under different environments (i.e. as a function of the stability properties of the large-scale currents). Even better, we wish to improve the theories if we find something really interesting.

Ocean eddies. Photo: NASA/Goddard Space Flight Center Scientific Visualization Studio

 

Published Mar. 7, 2018 10:26 AM - Last modified Mar. 7, 2018 10:51 AM

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