Vertical Cross Sections
In this chapter vertical cross sections are used to further investigate the different stages of the instant occlusion process.
Vertical Cross Sections (VCS)
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24 November 2005: 06 UTC |
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24 November 2005: 12 UTC |
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25 November 2005: 00 UTC |
Summary The vertical cross sections provided a deeper insight into the three-dimensional dynamics of the development. The following aspects were clarified in vertical cross section interpretation:
- In the beginning of the development the isentropes show a cold-front-inclined crowding zone in the area of the cloud band. In the region of the comma-like feature the isentropes show potential instability in lower layers.
- The fields of TA show a situation typical for a cold front and a strong influence of cold air behind the front.
- The merging process of the comma feature with the cloud band of the cold front could be nicely documented by a merging of two maxima of PVA.
- Covergence from low- to mid-levels is connected to the unstable zone of the comma and the cold front as well as vertical motion.
- The isotachs reveal the jet stream on the rear side of the cold front band as well as the storm over the Netherlands.
- A remarkable lowered tropopause is revealed by the fields of potential vorticity which seems quite unusual for an instant occlusion development.