Dataset: cp_decibels
Deployment: AL9801

AL9801 acoustic backscatter relative decibels, Georges Bank, 1998

Principal Investigator:

Peter H. Wiebe (Woods Hole Oceanographic Institution, WHOI)

BCO-DMO Data Manager:

Ms Dicky Allison (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

U.S. GLOBEC Georges Bank (GB)

Data URL:

https://www.bco-dmo.org/dataset-deployment/453365/data

Expand/Collapse All

Description

These relative decibel values are the result of processing the AL9801 Greene Bomber volume backscatter at 120KHz. They are relative decibel values derived from the backscatter data (in volts) and normalized according to the algorithms in the Matlab routine docurtainnf.m. The algorithm includes the following steps:

Add 10 to each value
Multiply result by 10¹⁰ to get values with units of m²/m³ (called sv)
Take the log (called SV)

These are energy backscattering values.

The values are presented as twenty groups of 20 numbers in each group. Each number is displayed as NNN, where there is an assumed decimal point at NN.N and all values should be negated. That is NNN, is really -NN.N.

See related objects:
cp_depths: https://www.bco-dmo.org/dataset/2393
cp_lat_lon: https://www.bco-dmo.org/dataset/2394

Methods & Sampling

Dataset acquisition description

Data Processing Description

Dataset Processing Description

More information about this dataset deployment

Funding

Award Number	Funding Source
unknown GB NOAA	National Oceanic and Atmospheric Administration
unknown GB NSF	National Science Foundation

Instruments

Greene Bomber

Supplied Name:

Supplied Description:

Instrument Type

Generic Name: Greene Bomber

Generic Description:

The Greene Bomber is a ENDECO V-fin towed body with overall dimensions of length: 139.7 cm; width at front: 66 cm; width at rear: 142.2 cm; height: 48.26 cm. It is constructed primarily of fiberglass. Since the early 1990's it has been towed just below the sea surface with acoustic and environmental sensors to provide continuous profiles of the water column acoustic backscattering and target strengths from zooplankton with a size range of ~ 1.5 mm to 100 mm, and sea surface environmental properties (temperature, salinity, and fluorescence). It was first used with a BioSonics dual-beam acoustic system operating at 420 kHz and 1 MHz or 120 and 420 kHz. The environmental sensing system (ESS) was the ESS used on MOCNESS. In 1997 the acoustics were changed to a HTI acousitic system with 120 and 420 kHz transducers. In 2010, two additional HTI transducers (43 and 200 kHz) were added. For additional detail see:

Wiebe, P. and C. Greene. 1994. The use of high frequency acoustics in the study of zooplankton spatial and temporal patterns. Proc. NIPR Symp. Polar Biol. 7: 133-157.

Wiebe, P.H., D. Mountain, T.K. Stanton, C. Greene, G. Lough, S. Kaartvedt, J. Dawson, and N. Copley. 1996. Acoustical study of the spatial distribution of plankton on Georges Bank and the relation of volume backscattering strength to the taxonomic composition of the plankton. Deep-Sea Research II. 43: 1971-2001.

Wiebe, PH; Stanton, T K; Benfield, M C; Mountain, D G; Greene, CH. 1997. High-frequency acoustic volume backscattering in the Georges Bank coastal region and its interpretation using scattering models. IEEE Journal of Oceanic Engineering22(3): 445-464.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
decibel_returns_1	relative decibel values	volts	Acc_bksctr
decibel_returns_2	relative decibel values	volts	Acc_bksctr
decibel_returns_3	relative decibel values	volts	Acc_bksctr
decibel_returns_4	relative decibel values	volts	Acc_bksctr
decibel_returns_5	relative decibel values	volts	Acc_bksctr
decibel_returns_6	relative decibel values	volts	Acc_bksctr
decibel_returns_7	relative decibel values	volts	Acc_bksctr
decibel_returns_8	relative decibel values	volts	Acc_bksctr
decibel_returns_9	relative decibel values	volts	Acc_bksctr
decibel_returns_10	relative decibel values	volts	Acc_bksctr
decibel_returns_11	relative decibel values	volts	Acc_bksctr
decibel_returns_12	relative decibel values	volts	Acc_bksctr
decibel_returns_13	relative decibel values	volts	Acc_bksctr
decibel_returns_14	relative decibel values	volts	Acc_bksctr
decibel_returns_15	relative decibel values	volts	Acc_bksctr
decibel_returns_16	relative decibel values	volts	Acc_bksctr
decibel_returns_17	relative decibel values	volts	Acc_bksctr
decibel_returns_18	relative decibel values	volts	Acc_bksctr
decibel_returns_19	relative decibel values	volts	Acc_bksctr
decibel_returns_20	relative decibel values	volts	Acc_bksctr

Database

Contribute Data

Dataset: cp_decibels
Deployment: AL9801

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: cp_decibelsDeployment: AL9801

Dataset acquisition description

Dataset Processing Description

Dataset: cp_decibels
Deployment: AL9801