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Ursa Astronomical Association
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00130 Helsinki
taivaanvahti(at)ursa.fi

Ursa Astronomical Association

Pearl clouds - 20.1.2022 at 15.36 Kuusamo, Rukatunturi Observation number 104048

Visibility II / V

Jani Päiväniemi, Ursa (Pohjois-Suomi)

At work, after dusk, I almost certainly noticed pearl clouds heading south / west. There might have been other types of clouds as well as shining in brighter spots on the shore of the sky. Too bad when the camera was not included but I tried to document what I saw on my cell phone.



More similar observations
Additional information
  • Havainto
    • Pearl clouds
  • Cloud coverage in the sky
    • Very small area
  • Nacreous clouds
    • Nacreous clouds, type I (acid) info

      Nacreous clouds (mother-of-pearl clouds) are clouds that occur in winter and are best seen at dusk in the morning and evening when the Sun is below the horizon.

      Although the name of pearl clouds refers to spectral colors, colorless, pale nacreous clouds are mainly observed in Finland. A striking feature related to pearl clouds in Finland is also the strong brown, which makes the landscape bathe in intense red or purple light.

      The Sky Watch has categories for colorless elections (type I) and colored (type II) pearl clouds, as well as the brown subtype.

      This selection reports type I colorless pearl clouds. While ordinary clouds are located in the lowest layer of the atmosphere in the troposphere, pearls form in the stratosphere above this at a height of 15 to 25 km above the ground. They occur when the stratosphere is exceptionally cold, about -75 ...- 85 C. The particles that cause pearls are either pure water ice (type II) or chemically different crystals, all of which contain nitric acid (type I) as an ingredient.

      Changes in stratospheric thermal conditions are quite sluggish, which is why pearl clouds are seen continuously for at least a few days unless the lower clouds obscure the view. Nacreous clouds can be extensive in their occurrence and can occur simultaneously throughout Finland. However, the focus of the performances is in Lapland. The appearance of nacreous clouds in the sky can be predicted by stratospheric temperature predictions.

      Nacreous clouds observations made in Finland from 1996 to 2014 show that they had been seen from December to March. Most occurred in December-January, in March nacreous clouds were reported in only one year. The particles responsible for the pearl clouds can also give rise to the Bishop ring. The Bishop’s ring may be a clear sign of nacreous clouds when the Sun is on the horizon. The pearl clouds themselves usually stand out when the Sun is on the horizon, but in this case they are usually very ghostly cloud fibers and easily go unnoticed

      Type I nacreous clouds. Image by Panu Lahtinen.

      Noctilucent clouds like nacreous clouds of type I. Image by Mikko Peussa.

      Half an hour before sunset, wavy nacreous clouds. These nacreous clouds stood out exceptionally well from the daytime sky. Image by Marko Riikonen.

    • Pearl clouds of type II (ice) info

      Pearl clouds (Nacreous clouds) are clouds that occur in winter and are best seen at dusk in the morning and evening when the Sun is below the horizon.

      Although the name of pearl clouds refers to spectral colors, colored (type II) pearls are rare in Finland. We mainly see colorless, pale (type I) pearls. A striking feature related to pearl clouds in Finland is also the strong brown, which makes the landscape bathe in intense red or purple light.

      The Sky Watch has categories for type I and II nacreous clouds, as well as the brown subtype. This selection reports pearl clouds representing type II spectral colors.

      While ordinary clouds are located in the lowest layer of the atmosphere in the troposphere, nacreous clouds form in the stratosphere above this at a height of 15 to 25 km above the ground. They occur when the stratosphere is exceptionally cold, about -75 ...- 85 C.

      The particles that cause pearl clouds are either pure water ice (type II) or chemically different crystals, all of which contain nitric acid (type I) as an ingredient.

      Changes in stratospheric thermal conditions are quite sluggish, which is why pearl clouds are seen continuously for at least a few days unless the lower clouds obscure the view. Nacreous clouds can be extensive in their occurrence and can occur simultaneously throughout Finland. However, the focus of the performances is in Lapland.

      The appearance of nacreous clouds in the sky can be predicted by stratospheric temperature predictions. Pearl cloud observations made in Finland from 1996 to 2014 show that they had been seen from December to March. Most occurred in December-January, in March pearl clouds were reported in only one year.

      The particles responsible for the pearl clouds can also give rise to the Bishop ring. The Bishop’s ring may be a clear sign of nacreous clouds when the Sun is on the horizon. The pearl clouds themselves usually stand out when the Sun is on the horizon, but in this case they are usually very ghostly cloud fibers and easily go unnoticed.

      In the winter of 2012-2013, Finland experienced an exceptionally long 13-day pearl cloud streak. On the second to last day of the episode, rare spectral colors also appeared in the clouds. Photo by Matti Helin.

Comments: 4 pcs
Timo Alanko - 21.1.2022 at 16.10 Report this

Hienot värit! Kyllä nuo happojen osalta ainakin Vaasassa olivat ihan varma tapaus. Tänään näyttää nihkeämmältä...

Jani Päiväniemi - 22.1.2022 at 16.28 Report this

Kiitos kommentista Timo! Pitää seurailla tilannetta jatkossakin.

Timo Alanko - 22.1.2022 at 22.40 Report this

Sodankylän luotauksissa lukemat olivat yli -80 astetta. Luvassa siis vielä lisää helmiäisiä pohjoisessa :)

Jani Päiväniemi - 23.1.2022 at 19.57 Report this

Timo, harmillisesti taivas on pysytellyt pilvisenä mutta toivotaan että kirkastuisi.

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