Vertical transport of turbulent kinetic energy in the surface layer over a paddy field

Abstract

Turbulent kinetic energy and its vertical flux were measured at two heights over a paddy field. The vertical transport of turbulent kinetic energy was always downward right above the paddy field and was frequently downward at higher levels within a few metres above the crop. Contributions to the downward transport arise mainly from the turbulent kinetic energy of horizontal wind velocity components. It is shown from the analysis of probability distributions that appreciable transport takes place intermittently in a few large downward bursts and that these downdrafts are efficient for downward energy transport.