Mesoscale eddies dominate oceanic kinetic energy at
sub-inertial frequencies. Their three-dimensional structure
has, however, remained obscure, hindering better
understanding of eddy dynamics. Here by applying the
composite analysis of satellite altimetry and Argo float
data to the globe, we show that despite remarkable regional
differences in amplitude, extent and polarity, etc., mesoscale
eddies have a universal structure in normalized stretched
coordinates. Horizontally, the associated pressure anomaly is
well described by a function of the normalized radial
distance from the eddy center R(rn)=(1−rn2/2)• exp(−rn2/2),
whereas vertically it is sinusoidal in a stretched coordinate
zs = ƒ z0 (N/f )dz, where N and f are the buoyancy frequency
and the Coriolis parameter.
