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Skywarden,
Ursa Astronomical Association
Kopernikuksentie 1
00130 Helsinki
taivaanvahti(at)ursa.fi

Ursa Astronomical Association

Other special clouds - 14.11.2016 at 16.20 Laitila Observation number 58406

Visibility V / V


in the "super moon" yacht, attention was drawn to the special clouds.

I have to say that I guess it was the first clouds for Kelvin-Heimholz for both of us! The phenomenon did not last long, but was really handsome!

I haven't seen anything like it before, so let's be happy :)


Additional information
  • Havainto
    • Other special clouds
  • Cloud coverage in the sky
    • Very small area
  • Other special clouds
    • Kelvin-Helmholtz cloud info

      The Kelvin-Helmholtz clouds are among the most exotic apparitions in the cloud world.

      They resemble regular waves in shape, typically several in succession. String wave strings are created at the top of the cloud mass when there are layers of air moving at different speeds in the air.

      If there is moisture in one layer of air, it may rise into waves in another layer of air moving at different speeds. There is Kelvin-Helmholtz instability between the air layers at that time, from which the cloud waves are named.

      Waves in lakes and seas are the result of this same instability between layers moving at different speeds. Kelvin-Helmholtz waves can also be seen in the gas circles of Jupiter and Saturn, for example.

      Only clearly wavy cases can be called Kelvin-Helmholtz clouds. It is good to be careful not to confuse them with conventional undulatus clouds. The cloud types can be difficult to identify, especially when viewed from the side.

      In a real Kelvin-Helmholtz cloud, the wave structure is clear. Only well-developed and undisputed Kelvin-Helmholtz clouds are collected to the Sky Watch database.

      Wavy Kelvin-Helmholz clouds. Image Grahamuk / Wikipedia.

      Tom Eklund observed these Kelvin-Helmholtz clouds in Finland.

Technical information

Canon EOS 6D, Canon 100-400mm f4.5, ISO 400, 1 / 100s

Comments: 4 pcs
Mia Heikkilä - 16.11.2016 at 23.16 Report this

Okei, nää on sellaisia. Viime kesältä itsellä havainto, ei kovin paljon kauempaa ;) Hinnerjoelta.

Panu Lahtinen - 17.11.2016 at 09.00 Report this

Vaikkei tässä olekaan ihan kaikkein puhtaimmat K-H:t kyseessä, niin on kuitenkin selvää että aaltoilu on pilven yläpinnalla, kuten pitää. Täten myös näkee ettei kyseessä ole esim. haihtumassa olevat undulatus-pilvet tai muu vastaava hämy, vaan ihan oikea K-H -instabiilius.

Pirjo Koski - 17.11.2016 at 10.38 Report this

Hienoa ja kiitos Panu! Nyt vaan kyttäämään josko joskus näkisi ihan "kunnolliset" KH:t! Olivat kyllä veikeän näköisiä. Onko näillä nimenomaisilla pilvillä nk. " esiintymisaikaa" vai voivatko näkyä vuoden ympäri? 

Matti Helin - 17.11.2016 at 16.38 Report this

Hyvän näköiset. Esiintymisestä; Kaippa noita näkyy ympäri vuoden. Itsellä on havaintoja kesä-,  joulu-,  helmi- ja tammikuulta. Näköjään kesäkuussa oli useampia. Eli omien vähien havaintojen perusteella voi nähdä ympäri vuoden, mutta kesäisin useimmin :p 

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