Quasi-Lagrangian energetics of an intense Mediterranean cyclone

Studies of the energetics of synoptic-scale systems and similar kinds of in vestigation have traditionally used a Eulerian framework. In this study, th e energetics of a synoptic-scale system have been considered using a quasi- Lagrangian method, in order to isolate the disturbance under consideration within a volume which moves together with the system at each stage of its d evelopment. Applying a Lagrangian framework implies that the dimensions of the computat ional area can be modified on the basis of predetermined criteria. In this study, an area surrounding a depression as shown on the surface analysis, h as been selected. This area moves together with the centre of the depressio n. The energetics results obtained using such a quasi-Lagrangian scheme are compared to those obtained by using a Eulerian framework. The synoptic-scale system studied here is a wintertime frontal depression, the greatest development of which occurred in the central Mediterranean on 7 December 1991. This depression moved east accompanied by significant temp erature changes, heavy precipitation and gale force winds.