Global Variability of the Wavenumber Spectrum of Oceanic Mesoscale Turbulence

The wavenumber spectra of sea surface height from satellite altimeter observations have revealed complex spatial variability that cannot be explained by a universal theory of mesoscale turbulence. Near the edge of the core regions of high eddy energy, agreement is observed with the prediction of the surface quasigeostrophic (SQG) turbulence theory, which has fundamental differences from that of the traditional quasigeostrophic (QG) turbulence theory. In the core regions of high eddy energy, the spectra are consistent with frontogenesis that is not fully accounted for by the SQG theory. However, the observations in the vast ocean interior of low eddy energy exhibit substantial differences from the predictions of existing theories of oceanic mesoscale turbulence. The spectra in these regions may reflect the ocean's response to short-scale atmospheric forcing and air sea interaction. The observations presented in this paper serve as a test bed for new theories and ocean general circulation models.