Generation of unbalanced motion at horizontal boundaries in the atmosphere and the oceans

The spectral analysis of a surface-temperature in the primitive equations has revealed how near-front motion, associated with the frontal waves known in the quasi-geostrophis approximations, are accompanied by weak unbalanced motion at high altitude. High-resolution simulation of surface-intensified ocean turbulence have shown how filamentary activity at the surface generate internal waves which propagate at depth. The amplitude of these waves has been estimated and found to be several orders of magnitudes smaller than the amplitudes of waves generated by tides and winds.