University of Tehran Press Journal of the Earth and Space Physics 2538-371X 25 1 1999 04 21 - - 13106 FA Journal Article 1970 01 01 The motion and behaviour of a Cut-Off Low centre are studied from baroclinic point of view. The development of a surface cyclone and associated Cut-Off Low formed at the east of the Mediterranean Sea on the 20th February, 1997, is investigated, together with various parameters, such as vertical motion and different types of vorticity, using a regular grid mesh of 19x15 points, at nine pressure levels, with constant 100 hPa intervals, from 1000 hPa to 200 hPa. Results of the numerical computation, presented in diagrams, along with synoptical reasonings show the development of the surface cyclone following the Cut-Off Low centre. It is quite apparent that the advection of the positive potential vorticity into the deep trough, present at the east of the Mediterranean Sea, has been the cause of the Cut-Off Low centre formation. In addition, because of the advection of the absolute vorticity together with the thickness advection, the surface baroclinic waves have been altered so that positive (negative) advection caused to strengthen (weaken) the waves. The motion and behaviour of a Cut-Off Low centre are studied from baroclinic point of view. The development of a surface cyclone and associated Cut-Off Low formed at the east of the Mediterranean Sea on the 20th February, 1997, is investigated, together with various parameters, such as vertical motion and different types of vorticity, using a regular grid mesh of 19x15 points, at nine pressure levels, with constant 100 hPa intervals, from 1000 hPa to 200 hPa. Results of the numerical computation, presented in diagrams, along with synoptical reasonings show the development of the surface cyclone following the Cut-Off Low centre. It is quite apparent that the advection of the positive potential vorticity into the deep trough, present at the east of the Mediterranean Sea, has been the cause of the Cut-Off Low centre formation. In addition, because of the advection of the absolute vorticity together with the thickness advection, the surface baroclinic waves have been altered so that positive (negative) advection caused to strengthen (weaken) the waves. https://jesphys.ut.ac.ir/article_13106_dc9d429150f43d006390588f09e1cdf1.pdf