'Close Cell' Cloud Structure

 
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Home > Contents > 'Convective Cells' - 'Close Cell' Structure - Description


"Convective Cells"
"Close Cell" Structure(CCS)

Some of the CCS are polygonal, round or oval, the others are often stay close to each other and form large fields up to more than a million square kilometers in size. Occasionally single cells may be discovered. The larger the cell is, the clearer its borders are (seen as thin lines). Through these lines the sea surface can be watched.
The area extent of an individual cell unit is from several kilometers to one hundred or even more kilometers.
The Cloud top heigh is normally from several hundred meters up to 2÷2.5 km., sometimes 1÷2 km., rarely up to 3÷3.5 km.
Albedo is 0.7÷0.8 (up to 0.9).

The 'Close Cell' Cloud Structure may shape:

  • above areas situated in middle latitudes where the temperature difference between the sea surface and the troposphere is little,
  • at the edge of cyclones vortices in middle latitudes,
  • above polar seas

The 'Close Cell' Cloud Structures are usually found (depending on the season) in the latitude of > 30° and <-20°.
It also occurs in the Northern Hemisphere above the Eastern part of the Atlantic and Pacific oceans, as well as above the Arabian Sea in the Indian Ocean, above the equator on the western coast of Africa and above South Americas Waters. In the Southern Hemisphere it extends up to the equator. Above Australian waters it stretches up to the latitude of 15°. Above the polar seas the clouds are semitransparent and consist of a quantity of small deep flowing cells.
This type of CS can be also found above the land, mostly the plains.
Various physical phenomena can emerge and be seen on the cloudiness of this structure type, besides other types of structures may use the said structure as the foundation for their evolution.

The Closed cells consist of convective clouds and their circulation is vertical. These cells appear frequently in the atmospheric layer in rough hexagonal rows, and consist of Stratocumulus and Stratus clouds. The sides of the cloud tops are kept down by the inversion layer. Closed cells appear when the temperature difference between the sea surface and the troposphere is minor. They may shape when the inflow of cool air is weak. Besides, they can convert from Opened cells in the event that the flowing cool air subsides. In this case the future form of cells (opened or closed) depends on the intensity of the inflow of the cool air. However this process is very chaotic and it is very difficult to predict the result of convention. Sometimes the conditions of the atmosphere change, which gives rise to curious forms of clouds.


Global Occurrence Diagram
Global occurrence diagram of 'Close Cell' Structure


Links

AEROGRAPHER'S MATE, MODULE 01--SURFACE WEATHER OBSERVATIONS
Integrated Publishing - Aerographer/Meteorology
Japan Meteorological Agency 2002
Analysis and Use of Meteorological Satellite Images, Chapter 3, Cloud patterns
Winter Meteorological Processes in the Atmosphere