Stability influences on transport of turbulent kinetic energy within a canopy: insight from simulations and observations

Turbulence within a plant canopy is typically in disequilibrium with local turbulence production and dissipation. It is generally understood under windy conditions that the distributed pressure drag induced by the canopy elements produces a region of high vertical shear of the horizontal wind near canopy top and that a significant portion of within-canopy turbulent kinetic energy is produced near canopy top and transported to regions within the canopy. A number of previous studies have investigated the mechanisms transporting turbulence to regions deep within a canopy (e.g., turbulent and pressure transport). However due to difficulties in making fast pressure measurements, a complete understanding of the transport of turbulence by pressure and how it varies with atmospheric stability remains elusive. Utilizing a combination of: 1) new canopy-resolving large-eddy simulation, and 2) observations collected during the Canopy Horizontal Array Turbulence Study, this presentation will discuss the influence of atmospheric stability on pressure transport of turbulence within a plant canopy. The talk will emphasize Dr. Bill Massman's contributions to both the simulations and the observations, and subsequent insight gained.