Occlusion: Cold Conveyor Belt Type
A CCB Occlusion is accompanied by a distinct cloud spiral; the cloud of the CCB Occlusion protrudes below the WF-CF cloud band and has lower tops.
An occlusion cold conveyor belt is characterized by a lower ceiling in comparison to the corresponding frontal system. In satellite imageries this lower cloudiness seems to be separated to the frontal cloud band. This is a result of the cold conveyor belt that transports cold sinking air into that region. Additionally the jet crosses the boundary between frontal system and the occlusion which is in contrast to general frontal systems. In consequence in the area of the occlusion the upper leves are rather dry (dry intrustion) due to sinking of dry, stratospheric air masses. This is the second reason why the occlusion cold conveyor belt appears in darker shades of grey than the corresponding frontal system.