Dept. of Geophysics Colloquium: Turbulent Transport over Height-Heterogeneous Canopies

Zoom: https://tau-ac-il.zoom.us/j/83888751261?pwd=36z53wLKBh2swtqb0scG5UTUYs2g95.1

Abstract:

Turbulent transport in the atmospheric boundary layer is a crucial mechanism driving biosphere-atmosphere exchange, with canopy flows governing the aerodynamics of both natural vegetation, such as forests, and built environments, like urban cities. Turbulent transport in and above the canopy differs fundamentally from classical boundary layer dynamics. In this region, referred to as the roughness sublayer (RSL), exchange is dictated by large-scale coherent motions. Consequently, traditional modeling that relies on classical gradient-diffusion closures (K-theory) systematically fails due to strongly non-local transport. Furthermore, because most of our theoretical understanding stems from idealized, uniform-height arrays, a critical gap remains in accurately modeling these non-local dynamics over realistic, height-heterogeneous terrains.

This seminar addresses this gap by presenting experimental results that examine how structural heterogeneity modifies turbulent transport and scalar dispersion. Using a simplified two-height canopy model in an environmental wind tunnel, the underlying turbulence and scalar exchange mechanisms were isolated and analyzed. By explicitly linking coherent canopy dynamics to non-local exchange, these findings provide a physically grounded approach to modeling complex surface-atmosphere interactions. Ultimately, this work illustrates why traditional surface-layer models assuming down-gradient transport break down over heterogeneous environments, offering new insights to improve predictive models for atmosphere-biosphere exchange.

Event Organizer: Dr. Leah Langer