Dataset: Integrated Acoustic Scattering BIP

Name: Nautical Area Scattering Coefficients (NASC) from an R/V BIP cruise in the Guaymas Basin, Gulf of California in 2013 (Jumbo Squid El Nino Response project)
Published: 2014-07-23
Keywords: oceans

Cite This Dataset

DOI:10.1575/1912/bco-dmo.520594.1

Spatial Extent: N:28.8857926 E:-111.3343637 S:27.24179 W:-113.3081006

Temporal Extent: 2013-10-20 - 2013-10-25

Project:

Adaptable life history strategy of a migratory large predator in response to El Nino and climate change (Jumbo Squid El Nino Response)

Principal Investigator:

Kelly Benoit-Bird (Oregon State University, OSU-CEOAS)

Contact:

Chad Waluk (Oregon State University, OSU-CEOAS)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2014-07-23

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Nautical Area Scattering Coefficients (NASC) from an R/V BIP cruise in the Guaymas Basin, Gulf of California in 2013 (Jumbo Squid El Nino Response project)

Abstract:

Integrated, area scattering values, or Natuical Area Scattering Coefficients (NASC) are provided from one cruise in the Guaymas Basin that occurred October 2013. Also included are the time (UTC) and location at the start and end of each integration bin, mean depth of the exclusion line for each bin, and the average thickness of the integrated cell. Note that noise removal from this data set (e.g. splash down, electrical interference, and CTD casts) was minimal before integration. Raw acoustic scattering data (.raw files) are extremely large. These are archived at Oregon State University and will be shared using physical media upon request.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2014-07-23	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.1575/1912/bco-dmo.520594.1	2019-12-30

Description

Note that noise removal from this data set (e.g. splash down, electrical interference, and CTD casts) was minimal before integration. Raw acoustic scattering data (.raw files) are extremely large. These are archived at Oregon State University and will be shared using physical media upon request.

Related References:
See Benoit-Bird & Gilly (2012) and Hoving et al. (2013).

Methods & Sampling

Acoustic data were collected nearly continuously using Simrad EK60s at 4 frequencies (38, 70, 120, and 200 kHz). Split beam transducers (Simrad model numbers: 38-12, 70-7c, 120-7c, 200-7c) were mounted 1.5 m below the surface on a rigid pole. Each transmitted a 512 us pulse as frequently as possible for the water depth. Raw data were stored using Simrad ER60 software.

Acoustic backscattering values at 38 kHz that were greater than -75 dB were integrated in 1 km horizontal bins from depths of 5m to 500m or 1 m above the bottom, whichever was shallower. These integrated, area scattering values or Nautical Area Scattering Coefficients (NASC: m2 nmi-2) are provided. Noise removal from this data set (e.g. splash down, electrical interference, and CTD casts) was minimal before integration.

Data Processing Description

BCO-DMO Processing Notes:
- Modified parameter names to conform with BCO-DMO naming conventions.
- Reformatted display of time from HH:MM:SS to HHMM.mmmm

Data Files

File
acoustics.csv (Comma Separated Values (.csv), 112.84 KB) MD5:0305092d8170d027cb69bfbb80fabb54 Primary data file for dataset ID 520594

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1338432

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
BIPXII_10_2013		2013-10-20	R/V BIP XII	William Gilly (Principal Investigator)	data info

Instruments

Simrad EK-60 echosounder

Supplied Description:

Instrument Type

Generic Name: Simrad EK-60 echosounder

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0198/

Generic Description:

A split-beam scientific echosounder primarily designed for fisheries research. It can operate seven frequencies simultaneously ranging from 18 to 710 kHz. Real time echo integration and target strength analysis in an unlimited number of layers is provided as well as storage of raw data for replay or analysis in one of several post-processing software packages such as Simrad's BI60.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
date_start	Date at start of integration bin. in the format YYYYmmdd	unitless	date_begin
time_start	Time (UTC) at start of integration bin in hours, minutes, and decimal minutes.	HHMM.mmmm	time_start
date_end	Date at end of integration bin. in the format YYYYmmdd	unitless	date_end
time_end	Time (UTC) at end of integration bin in hours, minutes, and decimal minutes.	HHMM.mmmm	time_end
NASC	Nautical Area Scattering Coefficient (NASC).	m2 nmi-2	no_bcodmo_term
lat_start	Latitude at start of integration bin.	decimal degrees	lat_start
lon_start	Longitude at start of integration bin.	decimal degrees	lon_start
lat_end	Latitude at end of integration bin.	decimal degrees	lat_end
lon_end	Longitude at end of integration bin.	decimal degrees	lon_end
exclusion_line_mean_depth	Mean depth of the exclusion line for each bin.	meters	no_bcodmo_term
integration_layer_thickness_mean	Average thickness of the integrated cell.	meters	no_bcodmo_term