A Family of Frontal Cyclones over the Western Atlantic Ocean. Part II: Parameter Studies

Abstract

In this study, a series of sensitivity experiments is performed to study the relative influence of latent heating, surface friction, and surface heat fluxes on the development of a family of frontal cyclones that occurred over the western Atlantic Ocean, using the simulation presented in Part I as a control run. It is shown that dry dynamics determines the initiation and track of all the frontal cyclones, and it accounts for about 59% of the deepening of a major frontal cyclone. Vorticity budget calculations reveal that in the absence of latent heating, preexisting upper-level cyclonic vorticity associated with a ring of potential vorticity provides the necessary forcing for the initiation and movement of the frontal cyclones, whereas the low-level thermal advection is responsible for a large portion of their amplifications as well as for their shallow circulations.