Effects of waving vegetation on turbulence in a forest canopy
Abstract
It is well known that the atmospheric flows in the canopy roughness sublayer (CRSL) strongly influence exchange between the biological elements of a forest and the atmosphere above. Despite several decades of research in this area, universally reliable theories do not yet exist. Most measures presenting flow statistics are for relatively short field campaigns, on the order of several weeks, giving no long-term climatology of flow within a canopy. It is often assumed that these conditions are representative of all time periods without much consideration to seasonal influences such as temperature or understory changes. Furthermore, little to no knowledge exists as to the effect of plant motion on these statistics. To address this, a field study has been underway for three years at the Howland Research Forest. The study site includes six three-dimensional sonic anemometers (3 at each of two towers), 149 tree sway sensors, and two pressure sensors to monitor turbulent fluctuations. The overall research goal of this project is to improve our understanding and modeling of the mechanisms underlying the aerodynamic interactions between turbulence structures in the canopy roughness sublayer (CRSL) and tree sway motions in a forest canopy. The work presented here concentrates on the variability of the long-term statistics of velocity profiles and turbulence in both time and space. Comparisons of these statistics in unstable and stable atmospheric conditions are also presented.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.H21C1067H
- Keywords:
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- 0315 ATMOSPHERIC COMPOSITION AND STRUCTURE Biosphere/atmosphere interactions;
- 0426 BIOGEOSCIENCES Biosphere/atmosphere interactions;
- 1843 HYDROLOGY Land/atmosphere interactions