Internal waves Research Papers - Academia.edu (original) (raw)

The overturning circulation of the ocean plays an important role in modulating the Earth's climate. But whereas the mechanisms for the vertical transport of water into the deep ocean--deep water formation at high latitudes--and... more

The overturning circulation of the ocean plays an important role in modulating the Earth's climate. But whereas the mechanisms for the vertical transport of water into the deep ocean--deep water formation at high latitudes--and horizontal transport in ocean currents have been largely identified, it is not clear how the compensating vertical transport of water from the depths to the surface is accomplished. Turbulent mixing across surfaces of constant density is the only viable mechanism for reducing the density of the water and enabling it to rise. However, measurements of the internal wave field, the main source of energy for mixing, and of turbulent dissipation rates, have typically implied diffusivities across surfaces of equal density of only approximately 0.1 cm2 s(-1), too small to account for the return flow. Here we report measurements of tracer dispersion and turbulent energy dissipation in the Brazil basin that reveal diffusivities of 2-4 cm2 s(-1) at a depth of 500 m ...

▪ We review the dynamics of stably stratified flows in the regime in which the Froude number is considered small and the Rossby number is of order one or greater. In particular we emphasize the nonpropagating component of the flow... more

▪ We review the dynamics of stably stratified flows in the regime in which the Froude number is considered small and the Rossby number is of order one or greater. In particular we emphasize the nonpropagating component of the flow field, as opposed to the internal wave component. Examples of such flows range from the later stages of decay of turbulent flows to mesoscale meteorological flows. Results from theoretical analyses, laboratory experiments, and numerical simulations are presented. The limiting form of the equations of motion appears to describe the laboratory experiments and numerical simulations rather well. There are similarities with the dynamics of two-dimensional flows, but three-dimensional effects are clearly important. A number of remaining open issues are discussed.

Proteus mirabilis colonies exhibit striking geometric regularity. Basic microbiological methods and imaging techniques were used to measure periodic macroscopic events in swarm colony morphogenesis. We distin-guished three initial phases... more

Proteus mirabilis colonies exhibit striking geometric regularity. Basic microbiological methods and imaging techniques were used to measure periodic macroscopic events in swarm colony morphogenesis. We distin-guished three initial phases (lag phase, first swarming phase, ...

The authors present a field study of estuarine turbulence in which profiles of Reynolds stresses were directly measured using an ADCP throughout a 25-h tidal day. The dataset that is discussed quantifies turbulent mixing for a water... more

The authors present a field study of estuarine turbulence in which profiles of Reynolds stresses were directly measured using an ADCP throughout a 25-h tidal day. The dataset that is discussed quantifies turbulent mixing for a water column in northern San Francisco Bay that experiences a sequence of states that includes a weak ebb and flood that are stratified, followed

Internal tide generation, propagation, and dissipation are investigated in Luzon Strait, a system of two quasi-parallel ridges situated between Taiwan and the Philippines. Two profiling moorings deployed for about 20 days and a set of... more

Internal tide generation, propagation, and dissipation are investigated in Luzon Strait, a system of two quasi-parallel ridges situated between Taiwan and the Philippines. Two profiling moorings deployed for about 20 days and a set of nineteen 36-h lowered ADCP–CTD time series stations allowed separate measurement of diurnal and semidiurnal internal tide signals. Measurements were concentrated on a northern line, where the ridge spacing was approximately equal to the mode-1 wavelength for semidiurnal motions, and a southern line, where the spacing was approximately two-thirds that. The authors contrast the two sites to emphasize the potential importance of resonance between generation sites. Throughout Luzon Strait, baroclinic energy, energy fluxes, and turbulent dissipation were some of the strongest ever measured. Peak-to-peak baroclinic velocity and vertical displacements often exceeded 2 m s−1 and 300 m, respectively. Energy fluxes exceeding 60 kW m−1 were measured at spring tid...

Internal waves of the fundamental mode propagating into a shoaling region have been studied experimentally in a continuously stratified fluid. The waves divide into three classes depending upon the ratio of the bottom slope γ to the... more

Internal waves of the fundamental mode propagating into a shoaling region have been studied experimentally in a continuously stratified fluid. The waves divide into three classes depending upon the ratio of the bottom slope γ to the wave-characteristic slope c. For γ/c < 1, the amplitude and wavenumber changes of the waves over the slope are in reasonable accord with a simple inviscid linear theory, prior to wave breakdown near the intersection of the slope and surface. Considerable mixing occurs in this corner region. When γ/c = 1, a striking instability of the bottom boundary layer is observed and the waves are heavily damped. When γ/c > 1, the waves are inhomogeneous and have complex spatial dependence.

Tidal energy dissipation is estimated for eight semidiurnal and diurnal constituents using a global inverse solution constrained by TOPEX/Poseidon altimeter data. Very similar spatial patterns are obtained for all semidiurnal... more

Tidal energy dissipation is estimated for eight semidiurnal and diurnal constituents using a global inverse solution constrained by TOPEX/Poseidon altimeter data. Very similar spatial patterns are obtained for all semidiurnal constituents, with about one third of the total ...

Abstract. The internal gravity waves of low frequency which are emitted at the base of the solar convection zone are able to extract angular momentum from the radiative interior. We evaluate this transport with some simplify-ing... more

Abstract. The internal gravity waves of low frequency which are emitted at the base of the solar convection zone are able to extract angular momentum from the radiative interior. We evaluate this transport with some simplify-ing assumptions: we ignore the Coriolis force, approxi- ...

Nature © Macmillan Publishers Ltd 1997 ... Leo RM Maas*, Dominique Benielli†, Joe¨l Sommeria† & Frans-Peter A. Lam* * Netherlands Institute for Sea Research, PO Box 59, 1790 AB Texel, The Netherlands † Ecole Normale et Superieure de Lyon,... more

Nature © Macmillan Publishers Ltd 1997 ... Leo RM Maas*, Dominique Benielli†, Joe¨l Sommeria† & Frans-Peter A. Lam* * Netherlands Institute for Sea Research, PO Box 59, 1790 AB Texel, The Netherlands † Ecole Normale et Superieure de Lyon, Laboratoire de Physique, 46 ...

Nonlinear dynamics of surface and internal waves in a stratified ocean under the influence of the Earth's rotation is discussed. Attention is focussed upon guided waves long compared to the ocean depth. The effect of rotation on... more

Nonlinear dynamics of surface and internal waves in a stratified ocean under the influence of the Earth's rotation is discussed. Attention is focussed upon guided waves long compared to the ocean depth. The effect of rotation on linear processes is reviewed in detail as well as the existing nonlinear models describing weakly and strongly nonlinear dynamics of long waves. The