The energy cycle and structural evolution of cyclones over southeastern South America in three case studies

Abstract

[1] In this paper, the Lorenz energy cycle over a limited area was applied for three cyclones with different origins and evolutions, where each of them was formed in an important cyclogenetic region near southeastern South America. The synoptic conditions and energetics were analyzed during each system's life cycle and showed important relationships between their energy cycle and the evolution of their vertical structure. In the case of the weak baroclinic cyclone which formed on Brazil's south-southeastern coast, the analysis showed that it originated through a midlevel cutoff low with contribution from barotropic instability. Its evolution would indicate potential transition to a hybrid system if the convective activity were stronger. The system that occurred in the La Plata River mouth had features of an oceanic bomb-type cyclogenesis and showed an important contribution from the available potential energy generation term through the latent heat release by the convection. Meanwhile, the system of the southern Argentina coast presented a classical baroclinic development of extratropical cyclogenesis in the energy cycle, from the wave amplification up to the final occlusion of the associated frontal system. These analyses revealed that the development of some cyclones that occur in eastern South America can present different mechanisms that are not related to the classical extratropical cyclogenesis.

Subtropical cyclones over the oceanic basins: a review

“…The three parameters of CPS are extremely useful to distinguish extratropical and tropical cyclones, different types of extratropical cyclones, tropical and extratropical transitions, and to characterize subtropical cyclones . Time evolutions through the storm lifecycle of B , – V T L , and – V T U are clearer in the phase diagram proposed by Hart.…”

“…The hybrid structure of subtropical cyclones is efficiently identified in CPS by positive -V T L due to their low-level warm core and negative -V T U associated with their upper level cold core. The three parameters of CPS are extremely useful to distinguish extratropical and tropical cyclones, 2 different types of extratropical cyclones, 12 tropical and extratropical transitions, [13][14][15] and to characterize subtropical cyclones. 6,7,16 Time evolutions through the storm lifecycle of B, -V T L , and -V T U are clearer in the phase diagram proposed by Hart 2 .…”

The Energy Cycle Associated to the Pacific Walker Circulation and Its Relationship to ENSO

“…In this energetic frame of reference the kinetic as well as the available potential energy are resolved into the amounts associated with the zonally averaged fields of motion and mass and the amounts associated with eddies ( [25,26]). Lorenz defined zonal kinetic energy (KZ) as the amount of kinetic energy which would exist if motion where purely zonal.…”

A Lorenz/Boer energy budget for the atmosphere of Mars from a “reanalysis” of spacecraft observations

“…Up to now, the Lorenz energy cycle scheme has been most commonly applied to the mean state of the terrestrial atmosphere. Local calculations of Lorenz energy budgets have also been employed, for instance, in studies of the eddy formation mechanism and evolution of cyclones [ Dias Pinto and da Rocha , ], local rainy seasons [ Berry and Thorncroft , ], or northern hemisphere winter jets [ Jiang et al , ], but such local studies typically require large additional energy transport terms as the boundaries of the studied region are permeable. In the global‐mean, energy cycles can be used to analyze discrepancies between reanalysis data sets [e.g., Oort , ; Li et al , ] or to validate model simulations with reanalysis data on the basis of their pattern of energy reservoirs and conversions [e.g., Boer and Lambert , ; Marques et al , ].…”