Related content

• Abyssal fan
• Abyssal plain
• Academic Press
• Acoustical oceanography
• Airy wave theory
• Altitude
• Amphidromic point
• Argo (oceanography)
• Atmospheric circulation
• Atmospheric tides
• Atoll
• Ballantine Scale
• Baroclinity
• Bathymetric chart
• Benthic lander
• Benthic zone
• Black smoker
• Boundary current
• Boussinesq approximation (water waves)
• Brackish
• Breaking wave
• Brunt–Väisälä frequency
• Buoyancy
• Category Coastal and oceanic landforms
• Category Ocean currents
• Category Physical oceanography
• Category Plate tectonics
• Category Tides
• Category Water waves
• Clapotis
• Cnoidal wave
• Coastal geography
• Cold seep
• Color of water
• Continental margin
• Continental rise
• Continental shelf
• Contourite
• Convergent boundary
• Coriolis effect
• Coriolis frequency
• Cross sea
• Current sea level rise
• Deep ocean water
• Deep sea
• Deep-ocean Assessment and Reporting of Tsunamis
• Density
• Dispersion (water waves)
• Dispersion relation
• Diurnal motion
• Divergent boundary
• Downwelling
• DSV Alvin
• Earth tide
• Eddy (fluid dynamics)
• Edge wave
• Ekman layer
• Ekman spiral
• Ekman transport
• El Niño-Southern Oscillation
• Equatorial waves
• Evanescent
• Fetch (geography)
• Fracture zone
• Fridtjof Nansen
• Future sea level
• Geostrophic current
• Global circulation model
• Global Ocean Data Analysis Project
• Global Sea Level Observing System
• Gravitational acceleration
• Gravity
• Gravity wave
• Group velocity
• Gulf Stream
• Guyot
• Halothermal circulation
• Head of tide
• Humboldt Current
• Hydroacoustics
• Hydrography
• Hydrostatic balance
• Hydrothermal circulation
• Hydrothermal vent
• Inertial waves
• Infragravity waves
• Internal tide
• Internal tides
• Internal wave
• International Standard Book Number
• Kelvin wave
• Landform
• Langmuir circulation
• Lee waves
• Littoral zone
• Longshore drift
• Loop Current
• Luke's variational principle
• Lunitidal interval
• Maelstrom
• Marginal sea
• Marine geology
• Marine pollution
• Mesopelagic
• Mid-ocean ridge
• Mild-slope equation
• Modular Ocean Model
• Modulational instability
• Mohorovičić discontinuity
• Mooring (oceanography)
• National Oceanographic Data Center
• North West Shelf Operational Oceanographic System
• Ocean
• Ocean acoustic tomography
• Ocean current
• Ocean dynamics
• Ocean energy
• Ocean exploration
• Ocean gyre
• Ocean observations

Internal wave

Internal waves are gravity waves that oscillate within, rather than on the surface of, a fluid medium. They are one of many types of wave motion in stratified fluids (another example being Lee waves). A simple example is a wave propagating on the interface between two fluids of different densities, such as oil and water. Internal wave motions are ubiquitous in both the ocean and atmosphere, where they create wave clouds. Nonlinear solitary internal waves are called solitons.

Suppose a water column is in hydrostatic equilibrium and displace a small packet of fluid with density Failed to parse (Missing texvc executable; please see math/README to configure.): \rho_0

. The balance between the force of gravity and the buoyant restoring force is disturbed, and the motion of the packet obeys the equation

where Failed to parse (Missing texvc executable; please see math/README to configure.): g

The Brunt–Väisälä frequency is an upper limit for the frequency in actual internal waves.

Most people think of waves as a surface phenomenon, which acts between water (as in lakes or oceans) and the air. Where low density water overlies high density water in the ocean, internal waves propagate along the boundary. They are especially common over the continental shelf regions of the world oceans and where brackish water overlies salt water at the outlet of large rivers. There is typically little surface expression of the waves, aside from slick bands that can form over the trough of the waves.