Appearance in Satellite Data

  • 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.

13 September 2004/12.00 UTC - Meteosat 8 IR 10.8 image
13 September 2004/12.00 UTC - Meteosat 8 WV 6.2 image
13 September 2004/12.00 UTC - Meteosat 8 VIS 0.6 image

The satellite image shows an anticyclonically curved cloud band of a Warm Conveyor Belt extending from Portugal (approximately 40N/6W) across the Bay of Biscay over France to Germany where it merges with the cloudiness of the Warm Front Band (approximately 54N/13E). 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 indicating high level ice clouds. Dark grey shades in this image represent the middle level cloudiness.

In the above example the Warm Conveyor Belt was clearly connected to the frontal system. An other example shows the Warm Conveyor Belt more isolated over northern Africa

01 July 2005/00.00 UTC - Meteosat 8 IR 10.8 image

The cloud band of the Warm Conveyor Belt extends from Morocco (31N/4W) to Tunis (36N/10E). Within the cloud band some convective cells can be recognised along the northern edge. Within the eastern part of the band over Tunis even a larger convective cell is recognised. The Warm Conveyor belt appears as grey to white in IR imagery.

01 July 2005/00.00 - Meteosat 8 RGB image (3.9, 6.2 and 7.3)

This example shows the typical cloud band enhanced using an RGB build from METEOSAT 8 channels NIR 3.9, WV6.2 and WV7.3. The red areas indicate the dry areas. The Warm Conveyor Belt is marked as blue which indicates that high amounts of water vapour are found at lower levels of the atmosphere. The light blue area over Tunis indicates that high amounts of water vapour are found throughout all layers of the atmosphere.