Kinetic Energy Budgets During the Life Cycle of Intense Convective Activity

Abstract

Synoptic-scale kinetic energy budgets are computed using 3 and 6 h rawinsonde data during a period of intense convective activity. Modification by the storms of their surrounding synoptic-scale environments is determined by calculating budgets over limited volumes that just enclose two squall lines. Large generation of kinetic energy is associated with areas of convection. Of particular interest is major transport of kinetic energy out of the volumes near the level of the jet stream. Kinetic energy generated in the lower levels of the storm environments is carried aloft by large-scale upward vertical motion. Transfer of kinetic energy from grid to subgrid scales of motion leads to a loss of energy in the storm environment. Temporal variations in the generation, flux divergence and dissipation terms of the kinetic energy budget are related to the life cycles of the squall lines. Maximum energy conversion and transport occur near the time of maximum storm intensity while smaller values are observed during the development and decay stages. Spatial fields of the energy terms show that the most intense energy processes occurring during the period are associated with the squall lines. The energy fields move with the squall line and synoptic map features.