Serendipitous Internal Wave Signals in Deep Argo Data

Serendipitous measurements of deep internal wave signatures are evident in oscillatory variations around the background descent rates reported by one model of Deep Argo float. For the 10,045 profiles analyzed here, the average root-mean-square of vertical velocity variances, < w ' 2 & rang; $\sqrt{\langle {w}<^>{\prime 2}\rangle }$, from 1,000 m to the seafloor, is 0.0045 m s(-1), with a 5%-95% range of 0.0028-0.0067 m s(-1). Dominant vertical wavelengths, lambda(z), estimated from the integrals of lagged autocorrelation sequences have an average value of 757 m, with a 5%-95% range of 493-1,108 m. Both < w ' 2 & rang; $\sqrt{\langle {w}<^>{\prime 2}\rangle }$ and lambda(z) exhibit regional variations among and within some deep ocean basins, with generally larger < w ' 2 & rang; $\sqrt{\langle {w}<^>{\prime 2}\rangle }$ and shorter lambda(z) in regions of rougher bathymetry or stronger deep currents. These correlations are both expected, since larger < w ' 2 & rang; $\sqrt{\langle {w}<^>{\prime 2}\rangle }$ and shorter lambda(z) should be found near internal wave generation regions.