medfate (version 4.7.0)

wind: 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"
)

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.

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).

Author

Miquel De Cáceres Ainsa, CREAF

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).

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

See Also

vprofile_windExtinction

Examples

#Default species parameterization
data(SpParamsMED)

#Load example plot plant data
data(exampleforest)

#Canopy height (in m)
h= max(exampleforest$treeData$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(exampleforest, 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)