The role of the environmental flow in the development of secondary frontal cyclones

Abstract

The impact of the environmental flow on the development of secondary frontal cyclones is investigated. Several case-studies are examined as examples of secondary frontal-cyclone events observed in the North Atlantic-western Europe sector. A simple measure of growth is defined to chart their development. The vorticity attribution technique of Bishop is utilized to calculate the action of the large-scale (environmental) flow on the fronts. In particular the environmental along-front stretching - shown to be important in theoretical models of frontal instabilities - is calculated. The role of the environmental deformation appears to be crucial: as part of a baroclinic life cycle, stretching def..