Distributions of available potential and kinetic energy budget quantities associated with wintertime cyclone activity along the eastern coasts of Asia and North America

Abstract

Available potential energy and kinetic energy budget quantities are examined during a two-week period of the Global Weather Experiment (GWE) winter season (14–28 February 1979) for regions encompassing the cyclogenetically active eastern coasts of Asia and North America. Twice daily values of vertically integrated available potential energy generation, kinetic energy generation, and kinetic energy boundary flux are produced using gridded isentropic data derived from the National Meteorological Center's Level IIIa set of global analyses. Available potential energy generation is found on average to be positive in the North American study region but negative in the East Asian domain, indicating net destruction of baroclinicity by the diabatic heating distribution in that sector of the northern hemisphere during the period. Spatial distributions of time-averaged available potential energy generation show little relationship to cyclone tracks in the North American or Asian study regions. However, the patterns of time-averaged kinetic energy generation correspond quite well to areas of rapid cyclone deepening and cyclone decay. In addition, temporal changes in regionally integrated kinetic energy generation values indicate that a strong rise in kinetic energy production accompanied each major cyclogenesis event within the study regions. Time series of the kinetic energy boundary flux reveal that the North American region is a net exporter of kinetic energy during the two-week study period. The Asian region is found to import more kinetic energy than it exports, thus representing a sink of kinetic energy for the northern hemisphere as a whole during the latter half of February 1979.