A type of coastally trapped wave motion where the velocity normal to the coast vanishes everywhere. The wave is nondispersive and propagates parallel to the shore with the speed of shallow water gravity waves, i.e. sqrt (gH). The profile perpendicular to shore either decays or grows exponentially seaward depending on whether the wave propagates with the coast to its right or left (in the northern hemisphere). For vanishing rotation, the decay or growth scale becomes infinite and the Kelvin wave reduces to an ordinary gravity wave propagating parallel to the coast. The dynamics of a Kelvin wave are such that it is exactly a linearized shallow water gravity wave in the longshore direction and exactly geostrophic in the cross-shore direction.
a vast accumulation of subsurface warming in the equatorial Pacific Ocean that has reached the northwest coast of South America
a warm pocket of subsurface water that tracks east, driven by east winds in the West Pacific)
A type of low-frequency gravity wave trapped to a vertical boundary (a coast or a mountain), or to the equator, which propagates counterclockwise around a basin in the northern hemisphere. The eastward phase speed for the first baroclinic mode in the Pacific Ocean is around 2.8 m/s, which means it would take a Kelvin wave about 2 months to cross the Pacific. The phase speed for the first baroclinic mode Kelvin wave in the atmosphere is about 40 m/s. Convectively-coupled Kelvin waves are also observed in the atmosphere and these move eastward near the equator at about 15 m/s.
The Kelvin wave is a gentle but huge swell of warm water in the Pacific Ocean. This mass of water is a few degrees warmer than surrounding water, is only 5-10 cm high, but is hundreds of kilometers wide.
A Kelvin wave is a wave in the ocean or atmosphere that balances the Earth's Coriolis force against a topographic boundary such as a coastline. A feature of a Kelvin wave is that it is non-dispersive, i.e., the phase speed of the wave crests is equal to the group speed of the wave energy for all frequencies. This means that it retains its shape in the alongshore direction over time.