Energy transformations associated with the synoptic and planetary scales during the evolution of a blocking anticyclone and an upstream explosively-developing cyclone

Energy transformations associated with a wave system that included the development of a blocking anticyclone over the North Atlantic Ocean and the upstream explosive-development of an extratropical cyclone are studied for the period 17–21 January 1979. Included in the investigation are eddy kinetic energy (KE), release of eddy potential energy (CE), generation of eddy kinetic energy (GK), and exchange between eddy and zonal kinetic energy (CK). In addition, these quantities were partitioned into synoptic-scale, planetary-scale, and scale-interaction components. Results indicate that KE, which was about one-half of the total kinetic energy, was maintained by baroclinic conversion of potential to kinetic. Further, as released potential energy was being utilized to generate KE, a portion of the KE was barotropically converted to zonal kinetic energy. These transformations were dominated by the synoptic-scale component, in contrast to the authors' previously-reported height tendency results, which yielded significant contributions from both the synoptic and scale-interaction components. Thus, while changes in the mass field depended not only on the synoptic scale but also on the interactions between the synoptic and planetary scales, the corresponding changes in the eddy motion fields responded largely to synoptic-scale processes.