WARM CONVEYOR BELT - CLOUD STRUCTURE IN SATELLITE IMAGES
by ZAMG
- In the satellite image the Warm Conveyor Belt looks like an anticyclonically curved cloud band usually in front
of, but separated from, the cloud band of the Cold Front.
- In the IR and WV images the grey shades of the cloud band of the Warm Conveyor Belt vary from grey to white.
- The fibrous character dominates but there may be bigger areas of smooth high cirrus cloudiness.
- In the VIS image the cloudiness of the Warm Conveyor Belt is much less; if there is any appreciable cloudiness it consists of
small single cells.
- As a consequence of the ascending Warm Conveyor Belt the grey shades in the IR image become continuously brighter from south to
north or north-east, from there on decreasing again while it turns to south-east where it comes under the influence of
sinking.
- During the life cycle some interactions between Warm Conveyor Belt and frontal cloud band can be observed:
- higher reaching cells may develop at the rear edge which is oriented to the approaching Cold Front;
- the anticyclonic part of the Warm Conveyor Belt may merge with the frontal cloudiness of the Cold
Front;
- sometimes the southern boundary of Cold Front bands show superimposed high cloud patches.
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19 April 1996/12.00 UTC - Meteosat IR image
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19 April 1996/12.00 UTC - Meteosat WV image
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19 April 1996/12.00 UTC - Meteosat VIS image
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The satellite image shows an anticyclonically curved cloud band of a Warm Conveyor Belt extending from the Atlantic west of Portugal (approximately 40N/10W) across the Bay of Biscay to the English Channel and south-west England where it merges with the cloudiness of the Cold Front band from the Atlantic (approximately 38N/25W) northward to south Ireland and Wales. As can be seen in the WV image cloudiness exists in a broad wet area and consists of vertically extended cells as well as isolated high Cloud Fibres. In the VIS image only the thick parts of the cloudiness can be recognized. Dark grey shades in this image represents middle level cloudiness.
15 April 1996/06.00 UTC - Meteosat IR image
The two cloud systems of the Warm Conveyor Belt (approximately 49N/25W to the Bay of Biscay and north Spain) and the Cold Front (approximately 40N/30W to 60N/10W) are clearly separated by a dark cloudless stripe. During the approach of the Cold Front band high cells have developed on the rear side of the Warm Conveyor Belt (approximately from 45N/21W to 48N/60W).
19 July 1995/18.00 UTC - Meteosat IR enhanced image
This example shows the typical cloud band of an Ana Cold Front (see Cold Front). Cloudiness is inclined backward on top of the frontal surface leading to the coldest tops close to the rear side of the band. This can be seen with the coloured stripes and areas representing tops colder than -30°C. The second coloured area from east Ireland across south Scotland, the North Sea to Denmark is on the leading edge of the cloud band and has developed in the highest part of the superimposed Warm Conveyor Belt (see
Meteorological physical background).