Atmospheric energetics as related to cyclogenesis over the eastern United States

Abstract

A method is presented to investigate the atmospheric energy budget as related to cyclogenesis. Energy budget equations are developed that are shown to be advantageous because the individual terms represent basic physical processes which produce changes in atmospheric energy, and the equations provide a means to study the interaction of the cyclone with the larger scales of motion. The work presented in this paper represents an extension of previous studies because all of the terms of the energy budget equations were evaluated throughout the development period of the cyclone. Computations are carried out over a limited atmospheric volume which encompasses the cyclone, and boundary fluxes of energy that were ignored in most previous studies are evaluated. Two examples of cyclogenesis over the eastern United States were chosen for study. One of the cases (1-4 November 1966) represented an example of vigorous development, while the development in the other case (5-8 December 1969) was more modest. Objectively analyzed data were used in the evaluation of the energy budget terms in order to minimize computational errors, and an objective analysis scheme is described that insures that all of the resolution contained in the rawinsonde observations is incorporated in the analyses. While computational errors may be serious due to errors in the measured data, particularly in the higher levels of the atmosphere, it is felt that the results of this study present a representative picture of energy processes during cyclogenesis. ...