Abstract

The Mediterranean Sea is recognized as one of the most important locations for cyclogenesis. In the course of this study, the role of subtropical jet stream in the formation of a deep cyclone over the central part of the Mediterranean Sea during 21 to 23, February 1974, was studied. The analysis based on NCEP data showed that there was a strong link between the presence of a subtropical jet along the African coast of Mediterranean Sea with the core speed of 60 to 70 ms^-1 and its associated secondary circulation with the formation of that cyclone. Analysis also showed that there were strong positive vorticity advection at 500 hpa and divergence in horizontal wind field at 200 hpa surfaces that led to the occurrence of ascending motion maxima at the time of the formation of the cyclone. 

Key words: Cyclogenesis, subtropical jet, divergence, positive vorticty advection (PVA).

Abbreviation

Abbreviations: SJT, Subtropical jet; PJ, polar jet; PVA, positive vorticity advention.