Monin.Obukhov.length {bigleaf}

Monin-Obukhov Length

Description

calculates the Monin-Obukhov length.

Usage

Monin.Obukhov.length(
  data,
  Tair = "Tair",
  pressure = "pressure",
  ustar = "ustar",
  H = "H",
  constants = bigleaf.constants()
)

Arguments

data

Data.frame or matrix containing all required variables

Tair

Air temperature (deg C)

pressure

Atmospheric pressure (kPa)

ustar

Friction velocity (m s-1)

H

Sensible heat flux (W m-2)

constants

Kelvin - conversion degree Celsius to Kelvin
cp - specific heat of air for constant pressure (J K-1 kg-1)
k - von Karman constant (-)
g - gravitational acceleration (m s-2)

Details

The Monin-Obukhov length (L) is given by:

L = - (\rho * cp * ustar^3 * Tair) / (k * g * H)

where rho is air density (kg m-3).

Value

L -

Monin-Obukhov length (m)

Note

Note that L gets very small for very low ustar values with implications for subsequent functions using L as input. It is recommended to filter data and exclude low ustar values (ustar < ~0.2) beforehand.

References

Foken, T, 2008: Micrometeorology. Springer, Berlin, Germany.

See Also

stability.parameter

Examples

Monin.Obukhov.length(Tair=25,pressure=100,ustar=seq(0.2,1,0.1),H=seq(40,200,20))