Secchi depth from diffuse attenuation coefficient(s).

Estimates the Secchi disk visibility depth using the Tyler (1968) approximation \(z_S \approx 1.7 / K_d\). When a spectral irradiance is supplied the function first computes an irradiance-weighted mean Kd across the visible range before applying the approximation.

Usage

secchi_depth(Kd, lambda = NULL, irradiance = NULL, spectrum = NULL)

Arguments

Kd

Diffuse attenuation coefficient(s) in 1/m.

lambda

Optional wavelength vector (nm) matching Kd.

irradiance

Optional spectral irradiance for PAR-weighted mean Kd.

spectrum

Optional lux_spectrum; when supplied its E and lambda slots replace the irradiance and lambda arguments.

Value

Secchi depth in metres.

References

Tyler JE (1968) Limnol. Oceanogr. 13:1-6. Preisendorfer RW (1986) Limnol. Oceanogr. 31:909-926.

See also

visual_range, jerlov_Kd, photic_depth

Examples

secchi_depth(jerlov_Kd("IA", lambda = 490))
#> [1] 78.7037