Talk:Kelvin wave

Need for more general explanation before technical details

It's good to see the template at the top of the article. There was an article in the Guardian today focusing on a major Coastal Kelvin wave moving towards California (https://www.theguardian.com/us-news/2026/sep/30/california-kelvin-wave-sea-level-rise). There were also articles in USA Today, Gizmodo, The New York Times, and the Atlantic over the last few days. If the phrase "Kelvin Wave" is becoming this popular, the wiki article should start looking like the Polar vortex article. I can help by editing for clariity, but it is not really my area of expertise to create substantive expansions. Grhabyt (talk) 17:32, 30 September 2026 (UTC)

I tried to figure out what this Guardian article is about, and couldn't. The data on the plot seem to show an equatorial wave that, on reaching the coast of South America, continues north as a coastal Kelvin wave. As for the "polar vortex" comparison, see L'Heureux's title for her tongue-in-cheek remark (her asterisk in the title is followed by "Okay, maybe not"). Викидим (talk) 14:13, 1 October 2026 (UTC) Викидим (talk) 05:09, 1 October 2026 (UTC)

The other Kelvin waves

Hallo,

There are actually two phenomenae called "Kelvin waves" - the others are the shear waves found in the shearing-sheet approximation made popular (in astrophysics, at least) by Goldreich and Lynden-Bell in 1965. These waves have a time dependent wavenumber k_x = q \Omega k_y t. I'd add this to the article but I actually came here seeking the original reference, so maybe once I've found that... 7daysahead (talk) 13:54, 17 January 2012 (UTC)

There are oh so many Kelvin waves, most yet to be described here. I have created Kelvin wave (disambiguation) to collect them. Викидим (talk) 21:19, 29 September 2026 (UTC)

Credit where credit is due

I was amazed to find no ref to Kelvin. Here, or on his page.

http://journals.cambridge.org/action/displayAbstract;jsessionid=DE35745A200A3AC1D8D4BAD3A899BB0A.journals?fromPage=online&aid=413288

needs proper formatting. FX (talk) 16:37, 7 March 2012 (UTC)

η

What is the meaning of η? — Preceding unsigned comment added by Hisan2026 (talk • contribs)

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Kelvin Wake image in Kelvin Wave article

There is an image of a Kelvin Wake in the Kelvin Wave article.

The Kelvin wake is NOT a Kelvin wave and this image should be removed. The wake is a type of surface gravity wave.

Wake (physics)#Kelvin wake pattern

Gravity wave HRabbeypark (talk) 01:59, 28 September 2026 (UTC)

I agree with this: the Kelvin wake and Kelvin wave are distinct phenomena. This image should be removed from the article. ~2026-52174-90 (talk) 14:41, 28 September 2026 (UTC)

Done! I am glad I looked here, because I saw the image, but without context to what a Kelvin wake was, the similar spelling had my mind make me read 'Kelvin wave' & the image confused me... Bpmcneilly (talk) 15:44, 28 September 2026 (UTC)

The article is mixing up very different phenomena

There are at least five wave-related things associated with Kelvin's name, the current text jumps from #1 to #2 and back without any clear explanations, making the text hardly comprehensible. There are no hatnotes or DAB pages either.

1. Coastal and equatorial Kelvin waves (in geophysical fluid dynamics): the waves in rotating shallow water that are trapped against a boundary, from the 1879 paper. Note that many sources treat these two as separate things (they really are).
2. Kelvin waves on vortex filaments: helical bending modes of a vortex line, from Kelvin's 1880 work on vortex vibrations. Today mostly discussed in superfluid turbulence (quantized vortices, "kelvons"), but still of some interest in classical physics, too. The article's second paragraph mentions this in one clause, then abandons it.
3. Kelvin wake ship-wave pattern: the V-shaped pattern behind a moving hull with the 19.47° half-angle, from Kelvin's 1887 stationary-phase analysis.
4. Kelvin–Helmholtz waves: shear-instability waves at an interface, "Kelvin waves" is sometimes used loosely for them in the cloud observation literature.
5. "Kelvin modes" in rotating-fluid inertial waves

I am planning to create a WP:DAB and hereby solicit input on the title arrangement (I woulld prefer the current title to redirect to a DAB, but the topic may be way too popular today for this to be practical). For now the DAB will have a title Kelvin wave (disambiguation). Викидим (talk) 19:26, 29 September 2026 (UTC)

Atmospheric waves

Need to have their own section. See Wang 2003 (already in the article) for details. Викидим (talk) 12:42, 1 October 2026 (UTC)

• Partially  Done, needs expansion. --Викидим (talk) 14:28, 1 October 2026 (UTC)

Relationship with tides

Needs to be explained. See also Poincaré wave, amphidrome. --Викидим (talk) 14:28, 1 October 2026 (UTC)

 Done Викидим (talk) 19:34, 2 October 2026 (UTC)

Factual problems

A few points that need fixing; the first is in the equatorial section, the rest in the coastal section.

1. ERA5 and the 2017 topology paper. The article says In 2017, using data from ERA5, equatorial Kelvin waves were shown to be a case of classical topologically protected excitations. Delplace, Marston and Venaille (2017, Science 358: 1075–1077) is a theoretical paper based on the shallow-water equations on a rotating sphere; it does not use reanalysis data, and ERA5 had not been released in 2017. I believe a later paper from the same group did use ERA5, but for stratospheric Poincaré–gravity waves rather than Kelvin waves (not yet checked). Proposed fix: drop "using data from ERA5".
2. Cross-shore velocity component. The text says Using the assumption that the cross-shore velocity v is zero at the coast, v = 0, but the equations that follow treat u as the cross-shore (x) component and v as alongshore (y); the later sentence If one assumes that u, the flow perpendicular to the coast, is zero is correct. Proposed fix: change the first instance to u = 0.
3. "Stratified" ocean. The section opens In a stratified ocean of mean depth H, but the continuity and momentum equations given are those for a single layer of uniform density (shallow-water model). The stratified (internal) case uses an equivalent depth and reduced gravity instead. Proposed fix: "In an ocean of uniform density and mean depth H", or simply drop "stratified".
4. Edge waves. The text lists coastal Kelvin waves among boundary waves, edge waves, trapped waves, or surface waves (similar to the Lamb waves). Edge waves are a distinct type: they are trapped by a sloping beach rather than by rotation, and can travel in either direction along the shore, whereas Kelvin waves need rotation and travel in one direction only. Proposed fix: remove "edge waves" from the list; the Lamb-wave comparison also looks unhelpful and could go.

Some smaller points on sourcing and presentation:

1. Page range for Wang 2003. The Wang citation currently has no page range, and the {{sfn}} locators follow the author's proof PDF (pp. 1–7), not the printed volume. L'Heureux (2015) gives the printed range as pp. 1062–1067, though she also misnames the work as Encyclopedia of Meteorology, so this needs checking against the print volume before adding |pages=. If the printed range is confirmed, the locators should either be re-mapped to print pages or the citation should say explicitly that they refer to the proof.
2. Variable naming in the equatorial section. The text says The dependence of the amplitude on x (here the north-south direction). The usual convention on the equatorial β-plane (and the one implied by f = βy a few lines earlier) is y for the north–south coordinate. Proposed fix: write the exponent in y and drop the parenthetical.
3. Gill 1982 cited twice. There is an unnamed full citation of Gill in the lead (with pp. 378–380) and a separate <ref name="Gill"> definition in the coastal section without pages, which is reused six times. These should be merged, preferably as {{sfn}} entries with page locators for each claim.
4. "Coriolis coefficient". The coastal section uses f is the Coriolis coefficient; the standard term (used elsewhere in the article) is Coriolis parameter.
5. Scope of the atmospheric section. The section gives no wave speeds and does not mention the quasi-biennial oscillation or the Madden–Julian oscillation, both covered by Wang (p. 6 of the proof). L'Heureux (2015, n. 3) also notes that atmospheric Kelvin waves are usually discussed as convectively coupled Kelvin waves (citing Kiladis et al. 2009, Rev. Geophys. 47: RG2003), which travel much more slowly than the dry waves (20–80 m/s) described by Wang. Worth adding if the section is expanded.

Викидим (talk) 14:07, 1 October 2026 (UTC)

 Done Викидим (talk) 07:11, 3 October 2026 (UTC)