Improving parameterization of scalar transport through vegetation in a coupled ecosystem-atmosphere model
Name
263684584-MIT.pdf
Description
Full printable version
Size
15.97 MB
Format
Adobe PDF
Checksum (MD5)
4316523ed0e15c509cdec3059a5a81a8
Author(s)
Link, Percy Anne
Advisor(s)
Peter Shanahan and Rafael Bras.
Date Issued
2008
Publisher
Massachusetts Institute of Technology
Abstract
Several regional-scale ecosystem models currently parameterize subcanopy scalar transport using a rough-wall boundary eddy diffusivity formulation. This formulation predicts unreasonably high soil evaporation beneath tall, dense forests and low soil evaporation beneath short, sparse grass. This study investigates alternative formulations by reviewing literature on flow and scalar transport in canopies, taking field measurements of subcanopy latent heat flux, and testing alternative model formulations in constrained numerical experiments. A field campaign was conducted in a dense rainforest in Luquillo National Forest, Puerto Rico, to measure wind and fluxes with eddy covariance devices. Wind velocities and fluxes of latent heat, sensible heat, and momentum were found to be much smaller below the canopy than above it. Modeling experiments tested a mixing-layer-based formulation of eddy diffusivity and a soil evaporation cutoff based on vortex penetration depth. The vortex penetration cutoff was found to be the most physically accurate and computationally simple option, and this study recommends that ecosystem and land-surface models adopt this formulation for subcanopy scalar transport.
Description
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.
Includes bibliographical references (p. 90-93).
Subjects
Civil and Environmental Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Terms of Use
M.I.T. theses are protected by
copyright. They may be viewed from this source for any purpose, but
reproduction or distribution in any format is prohibited without written
permission. See provided URL for inquiries about permission.
copyright. They may be viewed from this source for any purpose, but
reproduction or distribution in any format is prohibited without written
permission. See provided URL for inquiries about permission.
Persistent DSpace Link
