Roughness length — turb_roughness

Calculates the roughness length of a surface based on the obstacle height or the type of the surface.

Usage

turb_roughness_length(...)

# Default S3 method
turb_roughness_length(surface_type = NULL, obs_height = NULL, ...)

# S3 method for class 'weather_station'
turb_roughness_length(weather_station, ...)

Arguments

...: Additional arguments.
surface_type: Type of surface. Options: r surface_properties$surface_type
obs_height: Height of obstacle in meters (m).
weather_station: Object of class weather_station

Value

Numeric. Roughness length in meters (m).

Details

Possible surface types are: "field", "acre", "lawn", "street", "agriculture", "settlement", "coniferous forest", "deciduous forest", "mixed forest", "city", "water", "shrub".

You need to specify only one of surface_type or obs_height.

This function calculates the roughness length ($z_0$) of a surface. The roughness length is a measure of the roughness of the surface, which affects the wind profile near the ground. It can be calculated either based on the height of obstacles on the surface or by specifying the type of surface.

When the obstacle height (obs_height) is provided, the roughness length is calculated as 10% of the obstacle height.

When the surface type (surface_type) is provided, the roughness length is looked up from predefined values. The surface-class lookup values are package parameters. Bendix (2004) is cited as roughness-length method background.

References

Bendix 2004, p. 239

Examples

# Calculates roughness length based on obstacle height
turb_roughness_length(obs_height = 10)
#> [1] 1

# Calculate roughness length based on surface type
turb_roughness_length(surface_type = "deciduous forest")
#> [1] 1.5