  The mesoscale eddy field plays a key role in the mixing and transport of
physical and biological properties and redistribute energy budgets in the
ocean. Eddy kinetic energy is commonly defined as the kinetic energy of the
time-varying component of the velocity field. However, this definition contains
all processes that vary in time, including coherent mesoscale eddies, jets,
waves, and large-scale motions. The focus of this paper is on the eddy kinetic
energy contained in coherent mesoscale eddies. We present a new method to
decompose eddy kinetic energy into oceanic processes. The proposed method uses
a new eddy-identification algorithm (TrackEddy). This algorithm is based on the
premise that the sea level signature of a coherent eddy can be approximated as
a Gaussian feature. The eddy Gaussian signature then allows for the calculation
of kinetic energy of the eddy field through the geostrophic approximation.
TrackEddy has been validated using synthetic sea surface height data, and then
used to investigate trends of eddy kinetic energy in the Southern Ocean using
Satellite Sea Surface Height anomaly (AVISO+). We detect an increasing trend of
eddy kinetic energy associated with mesoscale eddies in the Southern Ocean.
This trend is correlated with an increase of the coherent eddy amplitude and
the strengthening of wind stress over the last two decades.
