hydrac.model.water

Water properties (hydrac.model.water)

class hydrac.model.water.Water(rho=1000, c=1480, T=None, S=None, P=None, preset=None)

Bases: object

Water properties class.

This class sets the water properties to be used for hydroaacoustic data water absorption correction and scattering model computation. It uses several features of the package hydrac.calcul.seawater (ex: water density calculation, sound speed velocity…).

Some default presets have been set for seawater, and rivers, as salinity plays an important role dor water density calculation.

Parameters:

rho : float

Water density in kg/m³

c : float

Sound velocity in water in m/s

T : float

Water temperature in degrees

S : float

Salinity in PSU

P : float

Depth in m

preset : str, {‘sea’,’river’}

Automatically loads the water parameters saved as presets in the package hydrac.util.constants

mean_TSCR(self, nm, mode_depl)

Computes the mean of the target variable nm over the given timeseries or profile.

Parameters:

nm : float (numpy.array)

parameter to be averaged

mode_depl : str, {‘Mooring’, ‘Cast’}

Deployment strategy

water_absorption_coefficient(self, f, id_time=None)

Computes the attenuation due to water using the François & Garrison (1982) model (https://doi.org/10.1121/1.388170).

Parameters:

f : float (numpy.array)

Sound frequency in Hz

id_time : int

Index at which the attenuaation is to be computed if wanted. Set to None by default, meaning attenuation is computed everywhere.

Returns:

alph : float (numpy.array)

Water absorption coefficient in dB/m for each frequency and each water parameter measurement.

static FBOH3(T, S)

Boric acid contribution to water absorption used in François & Garrison model (water_absorption_coefficient())

Parameters:

T : float

Temperature in degrees

S : float

Salinity in PSU

static FMgSO4(T, S)

Magnesium sulfate contribution to water absorption used in François & Garrison model (water_absorption_coefficient())

Parameters:

T : float

Temperature in degrees

S : float

Salinity in PSU

water_absorption_coefficient2(self, f, TT=None)

Computes the attenuation due to water with zeros salinity using the Ainslie & McColm (1997) model (https://doi.org/10.1121/1.421258) at low depth (z=0.5 m). This model is used as an alternative in case of lack of data regarding the water properties. Yet this model as presented here is only applicable to freshwater. With more information the François & Garrison model is used (water_absorption_coefficient())

Parameters:

f : float (numpy.array)

Sound frequency in Hz

TT : float

Temperature in degrees

Returns:

alph : float (numpy.array)

Water absorption coefficient in dB/m for each frequency for the peculiar temperature chosen by the user.

Classes

Water([rho, c, T, S, P, preset])

Water properties class.