near_field_correction {realTimeloads}

Near-field correction of Downing et al (1995)

Description

Computes dimensionless near-field correction

Usage

near_field_correction(freq, c, r, at)

Arguments

freq

Frequency of sound (Hz)

c

Speed of sound in water (m/s)

r

range to cell center measured along-beam (m)

at

Radius of ADCP transducer (m)

Value

Near-field correction (dimensionless)

Warning

See various references cautioning use of near-field correction (e.g., https://doi.org/10.1002/2016WR019695)

Author(s)

Daniel Livsey (2023) ORCID: 0000-0002-2028-6128

References

Downing, A., Thorne, P. D., & Vincent, C. E. (1995). Backscattering from a suspension in the near field of a piston transducer. The Journal of the Acoustical Society of America, 97(3), 1614-1620.

Examples

InputData <- realTimeloads::ExampleData
Sonde<- InputData$Sonde
freq <- InputData$ADCP$Accoustic_Frequency_kHz[1]*1000
S <- ctd2sal(Sonde$Conductivity_uS_per_cm,Sonde$Water_Temperature_degC,Sonde$Pressure_dbar)
c <- speed_of_sound(S,Sonde$Water_Temperature_degC,Sonde$Pressure_dbar)
at <- InputData$ADCP$Transducer_radius_m
r <- seq(0.1,10,0.1)
psi <- near_field_correction(freq,c[1],r,at[1])