© Markéta Augustinová

Zálší, Czech Republic

Latitude: 49° 13' 2'' N

Longitude: 14° 35' 53'' E

30 December 2014 1126 (Local Time)
Camera direction: towards SSE

Image P/S code: P.2.9

Image I.D.: 5631

C_L = 0, C_M = 0, C_H = 9

• Images & related info Other Images Images of 1987 edition
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  Cirrocumulus stratiformis undulatus cavum

  The thin layer of white, high cloud with small cloud elements whose apparent width is less than 1° is Cirrocumulus stratiformis; the variety undulatus is also present given the undulations orientated from the top left to the bottom right. There is the suggestion of a lower Cirrocumulus layer (duplicatus) on the left of the image, with larger undulations orientated from the left towards the top right. The detail of this, however, is rather obscured by a lower layer of Cirrus at 4 and 5, evident particularly in the top left of the picture and down the left side. 

  Nevertheless, the main feature of the picture is clearly the large hole in the top middle of the image, below which there is as a bright white fallstreak of ice crystals. The hole is the supplementary feature cavum, popularly known as a “fallstreak hole” or “hole-punch cloud”.

  The supplementary feature cavum is formed when glaciation occurs in a thin cloud layer consisting of supercooled water droplets in a liquid state at a temperature below 0 °C. As the supercooled water drops glaciate, the resulting ice crystals fall from the cloud layer to a lower level as virga, or fallstreaks. The resulting cloud hole typically grows larger with time as the glaciation process continues. 

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

  © Markéta Augustinová
  Zálší, Czech Republic
  Latitude: 49° 13' 2'' N
  Longitude: 14° 35' 53'' E
  30 December 2014 1126 (Local Time)
  
  
  Camera direction: towards SSE
  C_L = 0, C_M = 0, C_H = 9
  Image P/S code: P.2.9
  Image I.D.: 5631
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  The location was under the influence of a decreasing ridge of high pressure. A warm front was coming from the north-west.

  © Czech Hydrometeorological Institute (Creative Commons - CC)
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  Cirrocumulus stratiformis lacunosus cavum

  The photograph shows an extensive white patch of Cirrocumulus. It is composed of very small elements without shading, in the form of grains and ripples that have an apparent width of less than 1°. The image contains examples of the species stratiformis and floccus, and of the variety lacunosis. Towards the bottom of the image is the supplementary feature cavum in the form of a distrail, most likely formed by an aircraft flying through the cloud layer. 

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

  © Tak Leung Ng
  Chek Lap Kok, Hong Kong, China
  Latitude: 22° 18' 56'' N
  Longitude: 113° 55' 21'' E
  31 August 2006 1142 (Local Time)
  
  
  C_L = 0, C_M = 0, C_H = 9
  Image P/S code: S.2.9
  Image I.D.: 5096