© Frank Le Blancq

Portelet, St Brelade, Jersey

Latitude: 49° 10' 33'' N

Longitude: 2° 10' 27'' W

19 June 2013 2027 (Local Time)
Camera direction: towards N

Image P/S code: P.7.18

Image I.D.: 4715

C_L = 5, C_M = /, C_H = /

• Images & related info Other Images Images of 1987 edition
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  Stratocumulus asperitas

  The Stratocumulus stratiformis in this image (reported height 3 000 ft at nearby synoptic station Jersey Airport, Jersey) shows various shades of grey often typical of Stratocumulus. The cloud mass was sufficiently opaque to mask the Sun, which identifies it as belonging to the variety opacus. Of greatest interest is the dramatic-looking and highly exaggerated undulation reminiscent of a breaking wave that identifies it as the supplementary feature asperitas. Asperitas is more chaotic than undulatus, with less horizontal organization, and is in general characterized by waves in the cloud base that resemble a roughened sea surface seen from below. Variations in levels of illumination and cloud thickness can lead to dramatic visual effects. The dramatic feature in this photograph was visible for over 20 minutes with little change in structure and no detectable change in surface conditions as the cloud slowly drifted by.

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

  © Frank Le Blancq
  Portelet, St Brelade, Jersey
  Latitude: 49° 10' 33'' N
  Longitude: 2° 10' 27'' W
  19 June 2013 2027 (Local Time)
  
  
  Camera direction: towards N
  C_L = 5, C_M = /, C_H = /
  Image P/S code: P.7.18
  Image I.D.: 4715
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  A shallow low of 1 010 hPa was drifting west in the Bay of Biscay with a weak ridge building over Ireland. A weak north-easterly air flow covered the photo location in the English Channel.

  © Crown Copyright
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  The sounding from Brest, France (WMO 07110) 4 hours after the photograph was in the same air mass with a similar temperature and dew point (allowing for nocturnal cooling). A moist boundary layer is evident to approximately 930 hPa, with a weak inversion of nearly 2 °C at 975 hPa.

  © University of Wyoming
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  Stratocumulus stratiformis opacus asperitas

  This image shows a grey, extended layer of Statocumulus with some dark parts that is of the species stratiformis. The cloud is thick enough to completely mask the Sun and thus is of the variety opacus. The feature of most interest in this image is the well-defined wave-like structure (for example, at 2 and 3) on the underside of the cloud. The undulations here are more exaggerated and less organized than those found in the variety undulatus, and so are designated as the supplementary feature asperitas. For asperitas, the waves may be smooth, as in this image, or dappled with smaller features, sometimes descending into sharp points; it is as if one were viewing the sea surface from below. Variations in thickness and illumination of the cloud can lead to some dramatic visual effects. Nearby observations show the cloud base lowered to between 1 200 and 1 500 m (4 000 and 5 000 ft) around the time of the photograph, with showers and thunderstorms recorded to the north-east and north-west.

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

  © Joanne Kelly
  Great Harrowden, near Wellingborough, East Midlands, United Kingdom of Great Britain and Northern Ireland
  Latitude: 52° 19' 47'' N
  Longitude: 0° 42' 17'' W
  27 August 2016 1500 (Local Time)
  
  
  Camera direction: towards W
  C_L = 5, C_M = /, C_H = /
  Image P/S code: S.7.18 4
  Image I.D.: 4954
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  Stratocumulus stratiformis opacus asperitas

  This image shows a grey, extended layer of Statocumulus with some darker parts of the species stratiformis. It is sufficiently opaque that the Sun would be completely masked and thus is of the variety opacus. Of special interest is the well-defined wave-like structure on the underside of the cloud, seen at 2 and 3. The undulations are more exaggerated and less organized than in the variety undulatus and are designated as the supplementary feature asperitas, where the waves may be smooth or dappled with smaller features and sometimes descend into sharp points; it is as if one were viewing the sea surface from below. Variations in the thickness and illumination of the cloud can lead to some dramatic visual effects. At the time of this image, the measured cloud base of 1 820 m is at the top limit of the low cloud level and could possibly be mistaken for Altocumulus. 

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

  © Kairo Kiitsak
  Simuna, Lääne-Viru, Estonia
  Latitude: 59° 2' 43'' N
  Longitude: 26° 24' 3'' E
  21 October 2015 0824 (Local Time)
  
  
  Camera direction: towards SW
  C_L = 5, C_M = /, C_H = /
  Image P/S code: S.7.18 2
  Image I.D.: 5489
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  Stratocumulus stratiformis opacus asperitas

  The wave-like feature on the base of this Stratocumulus stratiformis opacus is the supplementary feature asperitas.

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

  © Yvonne Lui, David Lefer
  Arusha, United Republic of Tanzania
  Latitude: 3° 19' 46'' S
  Longitude: 36° 42' 56'' E
  27 August 2006 1700 (Local Time)
  
  
  Camera direction: towards SSW
  C_L = 5, C_M = /, C_H = /
  Image P/S code: S.7.18 10
  Image I.D.: 5575