FACTOR SEPARATION: AN EMERGING TOOL IN THE INVESTIGATION OF MEDITERRANEAN CYCLOGENESIS

Alpert, Pinhas (Department of Geophysics and Planetary Sciences, Tel Aviv Univ., Israel)

The factor separation method introduced by Stein and Alpert (1993, JAS) allows the separation of contributions of several factors to a specific field predicted by a model as well as those of contributions due to the various interactions or synergistic effects. This is of particular use for investigating Mediterranean cyclones where several factors like topography, sea fluxes and synoptic scale forcings, frequently act in unison in generating very special phenomena.

One example to be presented is the detailed analysis of the multi-stage evolution of the ALPEX cyclone on the 3-6 March 1982. It will be shown that synergism between mountain forcing and convection contributes to this lee intensification at a later stage when topography alone is starting to become cyclolytic.

A second example is of the fundamental role of initial conditions interacting with lateral boundaries updates in mesoscale simulations; a factor that was often underestimated.


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