© Albert de Nijs

Lima NV, Sweden

Latitude: 60° 56' 4'' N

Longitude: 13° 21' 44'' E

22 December 2014 1634 (Local Time)
Camera direction: towards W

Image P/S code: P.10U.1

Image I.D.: 4907

• Images & related info Other Images Images of 1987 edition
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  Polar stratospheric clouds: nacreous

  Polar stratospheric clouds composed primarily of ice are known as nacreous, or mother-of-pearl, clouds. After sunset they are characterized by brilliant iridescent colours, as shown in this photograph from Sweden. 

  Nacreous clouds only form in the stratosphere at a temperature below the ice frost point (typically near –85 °C) in the high latitudes of both hemispheres during the winter. They are often lenticular in shape.

    

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  © Albert de Nijs
  Lima NV, Sweden
  Latitude: 60° 56' 4'' N
  Longitude: 13° 21' 44'' E
  22 December 2014 1634 (Local Time)
  
  
  Camera direction: towards W
  Image P/S code: P.10U.1
  Image I.D.: 4907
• 

  Polar stratospheric clouds: nacreous

  Nacreous, or mother-of-pearl, clouds are a type of polar stratospheric cloud primarily composed of ice. They are typically wave clouds characterized by bright iridescent colours that become more brilliant in twilight. The clouds only form in the stratosphere, at low temperatures that are only reached in high latitude regions of the world during wintertime.  

  Links in the image description will highlight features on the image. Mouse over the features for more detail.

  © John Miles
  Shipton by Beningbrough, York, United Kingdom of Great Britain and Northern Ireland
  Latitude: 54° 1' 23'' N
  Longitude: 1° 8' 54'' W
  02 February 2016 0746 (Local Time)
  
  
  Camera direction: towards SE
  Image P/S code: S.10
  Image I.D.: 4894
• 

  Polar stratospheric clouds: nacreous

  Nacreous, or mother-of-pearl, clouds are a type of polar stratospheric cloud primarily composed of ice. These clouds only form in the stratosphere at a temperature below the ice frost point, typically near –85 °C. Such low temperatures in the stratosphere are only reached in the high latitudes in both hemispheres during their respective wintertimes.

  Nacreous clouds are characterized by iridescent colours, which become more brilliant in twilight, and typically take the form of lenticular wave clouds.   

  Links in the image description will highlight features on the image. Mouse over the features for more detail.

  © Svein Idar Iversen
  Gjøvik, Norway
  Latitude: 60° 47' 43'' N
  Longitude: 10° 41' 30'' E
  25 January 2008 1518 (Local Time)
  
  
  Camera direction: towards W
  Image P/S code: S.10
  Image I.D.: 4964
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  Polar stratospheric clouds: nacreous

  Nacreous clouds are seen here from an aircraft climbing through approximately 9 000 m (30 000 ft) over northern Norway.

  These polar stratospheric clouds are composed primarily of ice and are characterized by brilliant iridescent colours and a lenticular shape.

  Nacreous clouds only form in the stratosphere and in the high latitudes of both hemispheres during their respective winter seasons.

  Links in the image description will highlight features on the image. Mouse over the features for more detail.

  © Marco Quaranta
  northern Norway
  Latitude: 68° 46' 12'' N
  Longitude: 19° 20' 24'' E
  07 January 2017 1421 (Local Time)
  
  
  Image P/S code: S.10
  Image I.D.: 5602
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  Polar stratospheric clouds

  This time-lapse video from Marambio Base in Antarctica illustrates the standing wave nature of these lenticular polar stratospheric clouds. Note that they are partially obscured in places by some thin tropospheric cloud that moves from left to right, but the lenticular wave clouds remain stationary. The time lapse also illustrates the progression of colour through the twilight period. Shortly after sunset, the nacreous cloud is characterized by brilliant iridescent colours. The irisation is most brilliant when the Sun is several degrees below the horizon. Later, with the Sun still further down, the various colours are replaced by orange, which contrasts vividly with the darkening sky.

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  © Gustavo Copes

  Marambio Base, Antarctica

  Latitude: 64° 14' 32'' S

  Longitude: 56° 38' 44'' W

  09 August 2014 1500 (Local Time)

  
  

  Camera direction: towards W

  Image P/S code: S.10

  Image I.D.: Array
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  Nacreous clouds

  The height of the nacreous clouds shown above was determined by triangulation (base line 250 km) and found to be 20 km at 1300 hours and 24 km at 1630 hours. They were moving slowly from north or north-north-west. The clouds were observed all day. At 1515 hours, half an hour before sunset, they began assuming typical mother-of-pearl colours. Between 1600 and 1700 hours, "the display was very unusual and presented a constantly changing kaleidoscopic pattern". At the time the photograph was taken the colours were most brilliant, and diffuse shadows were cast on the snow. This brightness however did not last long. An intense (warm) anticyclone over the Aleutian Islands extended to a considerable elevation. The temperature at the 100 hPa surface (16 km) was -63°C. At 1630 hours there was an indication of a tropopause at the extremely high level of 90 hPa with a temperature of -66°C.

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  © J. Walden
  Anchorage, Alaska, United States of America
  Latitude: 61° 13' 5'' N
  Longitude: 149° 54' 1'' W
  24 January 1950 1645 (Local Time)
  
  
  Camera direction: towards WSW
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