Diploma Thesis: Rapid cyclogenesisWerner Schneider and Andreas BottRapid cyclogenesis or rapid cyclone development takes place whenever the pressure in the center of an extratropical low decreases more than 1 hPa per hour for at least 24 hours. During their development, most European winter storms run through a period of rapid cyclogenesis. Therefore, understanding the processes leading to rapid cyclone development is essential for the forecast of these storms. Experience shows that intrusion of dry stratospheric air into the upper troposphere near the center of a low is often associated with rapid cyclogenesis. Thus the question arises whether the stratospheric air with its high values of potential vorticity drives the rapid development of cyclones, or whether it is just a diagnostic process. In this diploma thesis, the COSMO model of the German Meteorological Service (DWD) is used to simulate different cases of rapid cyclogenesis over the North Atlantic and Europe in order to find out the forcing processes. Special interest is laid on the influence of stratospheric dry intrusion on rapid cyclogenesis. In the end, a new physical definition of rapid cyclogenesis by different forcing processes might be developed. |