Document Type

Article

Publication Date

10-2026

Subjects

Vegetated canopies

Abstract

It is well understood that vegetated canopies perturb the atmospheric flow within and immediately above the canopy, deviating from the inertial sublayer (ISL) regime characteristic of non-vegetated rough surfaces. Only above a certain height, denoted as the roughness sublayer height (RSL, π‘§βˆ—), do these flows return to ISL-like behavior. This distinction is critical, as parameterizations in Earth System Models (ESMs) are typically developed for ISL flows. Yet, most π‘§βˆ— estimates stem from studies over flat, homogeneous canopies and may be biased. In contrast, little is known about π‘§βˆ— in non-homogeneous or heterogeneous canopies that are not of agricultural interest, with irregular vegetation arrangements. Given that human activity has increasingly fragmented natural canopies, introducing gaps and multiscale heterogeneities, it is imperative to understand how the RSL height varies under such conditions. To address this gap, Large Eddy Simulations of the atmospheric boundary layer under geostrophic forcing are used to investigate how canopy heterogeneity influences the flow and π‘§βˆ—. Data is analyzed using the turbulent kinetic energy (TKE) budget equation with different averaging approaches. Additionally, the lacunarity metric is applied to measure spatial heterogeneity, and a canopy heterogeneity parameter, ℋ𝑐, is introduced. Results demonstrate that the effects of canopy heterogeneity on ABL flows are well captured by the dispersive production of TKE, which enables the identification of π‘§βˆ—. Further, a scaling relation between π‘§βˆ— and ℋ𝑐 is established, enabling correction of previously published π‘§βˆ— values for canopy heterogeneity.

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Copyright (c) 2026 The Authors

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