Cascade and intermittency of the sea surface temperature in the oceanic system

In this paper, we analyze the sea surface temperature obtained from the global drifter program. The experimental Fourier power spectrum shows a two-decade power-law behavior as E-theta(f) proportional to f(-7/3) in the frequency domain. Dimensional argument suggests a two-dimensional-like Lagrangian forward cascade, in which the enstrophy dissipation epsilon(Omega) is involved. Using the Hilbert-Huang transform and multi-level segment analysis, the measured high-order statistics and the corresponding singularity spectrum confirm the existence of the intermittency with a measured intermittency parameter mu(theta) similar or equal to 0.10, which is much weaker than the prediction by the conventional structure-function method.