acoustic_backscatter_processing {realTimeloads}

Process acoustic backscatter from hADCP

Description

Processes acoustic backscatter from horizontally profiling ADCP (hADCP). Returns attenuation of sound due to water and suspended-sediment. Applies all corrections to acoustic backscatter detailed in the guideline.

Usage

acoustic_backscatter_processing(
  Site,
  ADCP,
  Height,
  Sonde,
  Echo_Intensity_Beam_1,
  Echo_Intensity_Beam_2,
  Instrument_Noise_Level = NULL,
  Include_Rayleigh = FALSE,
  Include_near_field_correction = TRUE
)

Arguments

Site

Data frame with site, local vertical datum, and ADCP elevation information

Site_name

Site name (string)

Site_number

Unique site code (string)

ADCP_elevation_above_bed_m

Elevation of the ADCP above the bed (m)

ADCP_elevation_above_gauge_datum_m

Elevation of the ADCP above local gauge datum (m)

Distance_of_gauge_datum_below_thalweg_m

Distance from local gauge datum to lower point in cross-section (m)

Start_date_and_time

Installation date of ADCP (time, POSIXct)

End_date_and_time

Date if/when ADCP is moved vertically (time, POSIXct)

Comment

User comment (string)

ADCP

Data frame with various readings from ADCP

Site_number

Unique site code (string)

time

Date and time (time, POSIXct)

Ensemble

Measurment ensemble number (integer)

Accoustic_Frequency_kHz

Acoustic frequency of ADCP (kHz)

Transducer_radius_m

Radius of ADCP transducer (m)

Beam_angle_degrees

Angle of beam relative to normal (degrees)

Beam_aspect_ratio

Ratio of beam radius to beam length (-)

Range_to_bed_of_acoustic_beams_m

Normal range to bed, optional (m)

Range_to_water_surface_of_acoustic_beams_m

Normal range to water surface, optional (m)

Number_of_Cells

Number of measurement cells along beam (integer)

Bin_Size_m

Cell width measured normal to ADCP (m)

Blanking_distance_m

Blanking distance measured normal to ADCP (m)

Instrument_serial_number

Serial number of ADCP instrument (string)

CPU_serial_number

Serial number of ADCP CPU (string)

Ambient_Noise_Level_Beam_1_Counts

Ambient noise level for beam 1, optional (counts)

Ambient_Noise_Level_Beam_2_Counts

Ambient noise level for beam 2, optional (counts)

Distance_to_Bin_1_mid_point_m

Reported distance normal to ADCP to midpoint of bin/cell (m)

Distance_to_surface_m

Reported depth of ADCP from vertical beam, optional (m)

Speed_of_sound_m_per_s

Speed of sound used by ADCP in the field (m/s)

Temperature_degC

Temperature recorded by ADCP (degrees C)

Pressure_dbar

Pressure recorded by ADCP (dBar)

Salinity_PSU

Salinity in PSU recorded or assumed in ADCP data file, optional (PSU)

Distance_to_surface_m

Distance to water surface reported by vertical beam of ADCP (m)

Power_supply_voltage

Power to ADCP (V)

Height

Data frame with timeseries of river height

time

Date and time (time, POSIXct)

Height_m

Water surface elevation above gauge datum (m)

Site_number

Unique site code (string)

Sonde

Data frame with timeseries of conductivity, temperature, and depth from sonde

time

Date and time (time, POSIXct)

Water_Temperature_degC

Temperature (degrees C)

Conductivity_uS_per_cm

Conductivity (microS/cm)

Pressure_dbar

Pressure (dbar)

Site_number

Unique site code (string)

Echo_Intensity_Beam_1

Data frame of acoustic backscatter measurements from beam 2

Site_number

Unique site code (string)

time

Date and time (time, POSIXct)

Echo_Intensity_Counts_cell_n

Acoustic backscatter in nth cell (counts)

Echo_Intensity_Beam_2

Data frame of acoustic backscatter measurements from beam 2

Site_number

Unique site code (string)

time

Date and time (time, POSIXct)

Echo_Intensity_Counts_cell_n

Acoustic backscatter in nth cell (counts)

Instrument_Noise_Level

Estimate of noise level, recommended if ambient noise level is not recorded (counts)

Include_Rayleigh

Logical to include data within Rayleigh Distance for processing of acoustic backsactter

Include_near_field_correction

Logical to include near-field correction of Downing et al (1995)

Value

List with processed data, all variable names and units are written-out in list items, see Livsey (in review) for details of each variable

Author(s)

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

References

Livsey, D.N. (in review). National Industry Guidelines for hydrometric monitoring–Part 12: Application of acoustic Doppler velocity meters to measure suspended-sediment load. Bureau of Meteorology. Melbourne, Australia.

Examples

InputData <- realTimeloads::ExampleData
Site <- InputData$Site
ADCP <- InputData$ADCP
Height <- InputData$Height
Sonde <- InputData$Sonde
EIa <- InputData$Echo_Intensity
# example code assumes backscatter is equal across beams
EIb <- InputData$Echo_Intensity
Output <- acoustic_backscatter_processing(Site,ADCP,Height,Sonde,EIa,EIb)