by ZAMG and KNMI

Common Remarks

There are a lot of investigations of Occlusions explaining this conceptual model from different points of view:

It seems that there is no general agreement concerning Occlusions; for the purposes of this satellite meteorology manual the main viewpoint is the appearance in satellite imagery as well as the difference in the development stages. As Occlusions are long-lived phenomena this development phase might be shorter than the stage of a well-developed cloud spiral where no important differences in the cloud configuration can be recognized any longer.

Nevertheless sub-types of the Occlusion which do not manifest in the satellite cloud structure but in other parameters, and which are the outcome of experiences of weather services, will be mentioned in the relevant chapters.

The cloud band of the Cold Conveyor Belt Type Occlusion described in this chapter develops like the Occlusion of the classical type (see Occlusion: Warm Conveyor Belt Type ), similar also as in wave development. (see Wave ) However, in contrast to the Occlusion of the Warm Conveyor Belt type it shows clearly different cloud layers. Investigations over about one year, which were made at ZAMG, have shown that the development of the Warm Conveyor Belt type of Occlusion could hardly be observed in the satellite image. In most cases the cloud spiral develops from an Occlusion of the Cold Conveyor Belt type. In the mature stage it generally is not possible to discriminate between the Warm Conveyor Belt Occlusion and the Cold Conveyor Belt Occlusion. Both types show a multi-layered cyclonically curved cloud spiral in the satellite image.