Derived Parameters
Basic synoptic parameters like geopotential height at different pressure levels as seen in the chapter before cannot explain the entire synpotic development. Therefore satellite images in combination with other derived meteorological parameters are presented in this chapter.
The key parameters for a rapid cyclogenesis are:
- Geopotential at 1000 hPa (see previous chapter)
- Temperature Advection at 700 hPa
- Positive Vorticity Advection at 300 hPa
- Isotachs at 300 hPa
- Height of PV = 1 unit
Jets (Isotachs) + PVA 300 hPa, IR Images: time sequence
In this chapter the cloud configurations seen in IR images are related to isotachs and PVA. 6-hourly sequences are shown.
Temperature Advection 700 hPa, IR Images: time sequence
In this chapter the cloud configurations seen in IR images are related to temperature advection at 700 hPa. 6-hourly sequences are shown.
Height of PV=1 unit, WV Images: time sequence
In this chapter the cloud configurations seen in WV images are related to PV=1. 6-hourly sequences are shown.
Summary of the investigations in this chapter
The following conclusions can be drawn from the presented parameters:
- A strong jet stream up to 80 m/s is involved in the development. The rapid cyclogenesis takes place in the left exit region of the jet coinciding well with a clear PVA Maximum. Two branches of the jet stream can be noticed, one along the rear edge of the frontal cloud band and the other on the poleward side of the cloud head.
- A very strong cold advection and a huge temperature contrast characterize the situation in this case study. Cold advection can be found between the rearward part of the cloud head and the cold front band. Warm advection characterizes the eastern part of the cloud head.
- Downward-protruding stratospheric air could be documented by model fields of PV=1. A PV anomaly can be observed which coincides very well with the dry slot in WV images. This parameter also reveals a second decoupled process south of the rapid cyclogenesis.