DYNAMICS AND ENERGETICS OF CONVECTIVE PLUMES IN THE ATMOSPHERIC SURFACE-LAYER

Budgets of horizontal and vertical momentum and of turbulent kinetic energy in vertical direction within updrafts of convective plumes are evaluated, using experimental observations of velocities and temperatures and the corresponding pressure fluctuations calculated by a low-order dynamic model of plumes. The force balances revealed by the momentum budget study agree with the shape-preservation mechanisms for the plumes observed experimentally. The transport and redistribution of turbulent kinetic energy seen from the study of the budgets explain the relatively long lifetime of the convective plumes. Detailed pressure distributions within a convective plume and the role of the translation velocity in the development of the convective plume are discussed using the simulated flow fields.