wind: Models for canopy turbulence
In medfate: Mediterranean Forest Simulation

wind	R Documentation

Models for canopy turbulence

Description

Models for canopy turbulence by Katul et al (2004).

Usage

wind_canopyTurbulenceModel(zm, Cx, hm, d0, z0, model = "k-epsilon")

wind_canopyTurbulence(
  zmid,
  LAD,
  canopyHeight,
  u,
  windMeasurementHeight = 200,
  model = "k-epsilon"
)

Arguments

`zm`	A numeric vector with height values (m).
`Cx`	Effective drag = Cd x leaf area density.
`hm`	Canopy height (m).
`d0`	Zero displacement height (m).
`z0`	Momentum roughness height (m).
`model`	Closure model.
`zmid`	A numeric vector of mid-point heights (in cm) for canopy layers.
`LAD`	A numeric vector of leaf area density values (m3/m2).
`canopyHeight`	Canopy height (in cm).
`u`	Measured wind speed (m/s).
`windMeasurementHeight`	Height of wind speed measurement with respect to canopy height (cm).

Details

Implementation in Rcpp of the K-epsilon canopy turbulence models by Katul et al (2004) originally in Matlab code (https://nicholas.duke.edu/people/faculty/katul/k_epsilon_model.htm).

Value

Function wind_canopyTurbulenceModel returns a data frame of vertical profiles for variables:

z1: Height values.
U1: U/u*, where U is mean velocity and u* is friction velocity.
dU1: dUdz/u*, where dUdz is mean velocity gradient and u* is friction velocity.
epsilon1: epsilon/(u^3/h) where epsilon is the turbulent kinetic dissipation rate, u* is friction velocity and h is canopy height.
k1: k/(u*^2), where k is the turbulent kinetic energy and u* is friction velocity.
uw1: <uw>/(u*^2), where <uw> is the Reynolds stress and u* is friction velocity.
Lmix1: Mixing length.

Function wind_canopyTurbulence returns a data frame of vertical profiles for transformed variables:

zmid: Input mid-point heights (in cm) for canopy layers.
u: Wind speed (m/s).
du: Mean velocity gradient (1/s).
epsilon: Turbulent kinetic dissipation rate.
k: Turbulent kinetic energy.
uw: Reynolds stress.

Author(s)

Miquel De Cáceres Ainsa, CREAF

References

Katul GG, Mahrt L, Poggi D, Sanz C (2004) One- and two-equation models for canopy turbulence. Boundary-Layer Meteorol 113:81–109. https://doi.org/10.1023/B:BOUN.0000037333.48760.e5

Examples

#Default species parameterization
data(SpParamsMED)

#Load example plot plant data
data(exampleforestMED)

#Canopy height (in m)
h= max(exampleforestMED$treeData$Height/100) 
d0 = 0.67*h
z0 = 0.08*h

#Height values (cm)
z = seq(50,1000, by=50)
zm = z/100 # (in m)

# Leaf area density
lad = vprofile_leafAreaDensity(exampleforestMED, SpParamsMED, draw = FALSE,
                               z = c(0,z))
  
# Effective drag
Cd = 0.2
Cx = Cd*lad
  
# canopy turbulence model
wind_canopyTurbulenceModel(zm, Cx,h,d0,z0)

medfate documentation built on Aug. 29, 2023, 5:07 p.m.