Accession Number : ADA322872

Title :   A Study of Planetary Boundary Layer Forcing on the Turbulent Flow Characteristics of Tree Canopies Using Project Wind Data.

Descriptive Note : Final progress rept. 1994-1996,

Corporate Author : CONNECTICUT UNIV STORRS

Personal Author(s) : Miller, David R. ; Yang, X. H.

PDF Url : ADA322872

Report Date : 28 FEB 1997

Pagination or Media Count : 33

Abstract : A non-local closure numerical model based on the Transilient Turbulence Theory (TTT) has been developed and verified in and above a homogeneous tree canopy. The first order volumetrically averaged governing equations for momentum, heat and humidity were coupled dynamically with canopy processes such as evapotranspiration and radiation within the canopy. The simulated profiles of momentum, heat, and humidity, were compared to measurements in a homogeneous orchard during project WIND. The model provides evidence that non-local turbulence closure by TTT is a consistent and efficient technique to parameterize the turbulent transport near the ground in canopies as well as above and can be incorporated into numerical models. The spatial resolution in surface parameterizations for spatially distributed models was quantified using spatial autocorrelations. The resulting error prediction model was used to quantify the statistical errors due averaging different patch sizes and contrasts. Sensitivity of process models to these averaging errors in boundary conditions was quantified using probable error vectors. Overall these efforts have rigorously set the stage for future use of the non-local turbulent transport approach and as an efficient and accurate method to model spatially distributed canopy flow in three dimensions.

Descriptors :   *TURBULENT FLOW, *EVAPOTRANSPIRATION, *TREE CANOPY, MATHEMATICAL MODELS, ALGORITHMS, SPATIAL DISTRIBUTION, ATMOSPHERIC TEMPERATURE, AUTOCORRELATION, COMPUTATIONAL FLUID DYNAMICS, METEOROLOGICAL DATA, TREES, WIND DIRECTION, WIND VELOCITY, HUMIDITY, ORCHARDS, BOUNDARY LAYER FLOW.

Subject Categories : Forestry
      Fluid Mechanics
      Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE