Estimate attenuation of sound pressure level

attenuation() estimates atmospheric attenuation and atmospheric absorption, calculating the geometric, atmospheric, and habitat attenuation, as well as the overall expected attenuation (the sum of the other three), based on temperature, relative humidity, atmospheric pressure, and sound frequency.

Usage

attenuation(
  frequency,
  dist0,
  dist,
  temp = 20,
  rh = 60,
  pa = 101325,
  hab.att.coef = 0.02
)

Arguments

frequency: Numeric vector of length 1 with frequency (in Hertz).
dist0: Numeric vector of length 1 with distance (m) for the reference SPL.
dist: Numeric vector of length 1 with distance (m) over which a sound propagates.
temp: Numeric vector of length 1 with temperature (in Celsius). Default 20.
rh: Numeric vector of length 1 with relative humidity (in percentage). Default 60.
pa: Numeric vector of length 1 with atmospheric (barometric) pressure in Pa (standard: 101325, default). Used for atmospheric attenuation.
hab.att.coef: Attenuation coefficient of the habitat (in dB/kHz/m).

Value

A data.frame with the geometric, atmospheric, and habitat attenuation (in dB), as well as the combined attenuation.

Details

Attenuation values are given in dB. The function is modified from http://www.sengpielaudio.com and https://scikit-maad.github.io/generated/maad.spl.attenuation_dB.html#maad.spl.attenuation_dB.

References

Araya-Salas, M., Grabarczyk, E. E., Quiroz-Oliva, M., Garcia-Rodriguez, A., & Rico-Guevara, A. (2025). Quantifying degradation in animal acoustic signals with the R package baRulho. Methods in Ecology and Evolution, 00, 1-12. https://doi.org/10.1111/2041-210X.14481

Author

Marcelo Araya-Salas (marcelo.araya@ucr.ac.cr)

Examples

{
  # measure attenuation
  attenuation(frequency = 2000, dist = 50, dist0 = 1)
}
#>   frequency dist geometric.attenuation atmospheric.attenuation
#> 1      2000   50               33.9794               0.4547757
#>   habitat.attenuation combined.attenuation
#> 1                1.96             36.39418