Dataset: acoustic backscatter120 kHz

Name: 120 kHz acoustic backscatter in relative decibels from RVIB Nathaniel B. Palmer cruises NBP0103 and NBP0103 in the Southern Ocean in 2001 (SOGLOBEC project; Southern Ocean Krill project)
Published: 2001-12-03
Keywords: oceans

Cite This Dataset

Project:

GLOBEC: Winter Distribution and Success of Southern Ocean Krill (Southern Ocean Krill)

U.S. GLOBEC Southern Ocean (SOGLOBEC)

Program:

U.S. GLOBal ocean ECosystems dynamics (U.S. GLOBEC)

Principal Investigator:

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

BCO-DMO Data Manager:

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

Version:

final

Version Date:

2001-12-03

Restricted:

Validated:

Yes

Current State:

Final no updates expected

120 kHz acoustic backscatter in relative decibels from RVIB Nathaniel B. Palmer cruises NBP0103 and NBP0103 in the Southern Ocean in 2001 (SOGLOBEC project; Southern Ocean Krill project)

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Description

These relative decibel values are the result of processing the NBP0104 and NBP0103 volume backscatter data from BIOMAPER-II 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^-10 to each value
Multiply result by 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 the related objects sv120coords_0104 and sv120depths_0104 for NBP0104 and sv120amcoords_0103, sv120pmcoords_0103 and sv120depths_0103 for NBP0103.

Methods & Sampling

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

These are energy backscattering values.

Data Processing Description

See the related objects sv120amcoords_0103, sv120pmcoords_0103 and sv120depths_0103 for NBP0103.

Data Files

File
RVIB NBP0103 Afternoon Position Data filename: sv120pmcoords_0103.tsv (Tab Separated Values (.tsv), 64.21 KB) MD5:705b21add493c156a746603c97a26e97 The Time and Position data associated with the Volumne Backscattering data from NBP0103 collected in the afternoon.
RVIB NBP0103 Depth Data filename: sv120depths_0103.tsv (Tab Separated Values (.tsv), 5.47 KB) MD5:e000ff5699bc2ab8cb1b5509515bce4c Depths associated with the NBP0103 sv120 data. These depths are the same for both the morning and afternoon data.
RVIB NBP0103 Morning Position Data filename: sv120amcoords_0103.tsv (Tab Separated Values (.tsv), 101.90 KB) MD5:03f9ad797b598aa03df0bcfb3270f4d0 The Time and Position data associated with the Volumne Backscattering data from NBP0103 collected in the morning.
RVIB NBP0104 Depth Data filename: sv120depths_0104.tsv (Tab Separated Values (.tsv), 5.47 KB) MD5:e000ff5699bc2ab8cb1b5509515bce4c Depths assocated with the NBP0104 sv120 data.
RVIB NBP0104 Position Data filename: sv120coords_0104.tsv (Tab Separated Values (.tsv), 1.54 MB) MD5:a40070ff404599e18e8583fa66bf936e Time and Position data associated with the Volume Backscattering data from NB0104.
sv120data.csv (Comma Separated Values (.csv), 63.76 MB) MD5:fb74be443863d5fa04f55641ac414fe9 Primary data file for dataset ID 2385

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Antarctic Sciences	ANT-9910307

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
NBP0103	GLOBECI	2001-04-24	RVIB Nathaniel B. Palmer	Peter H. Wiebe (Chief Scientist)	data info
NBP0104	GLOBECII	2001-07-22	RVIB Nathaniel B. Palmer	Peter H. Wiebe (Chief Scientist)	data info

Instruments

BIo-Optical Multi-frequency Acoustical and Physical Environmental Recorder II

Supplied Description:

These relative decibel values are the result of processing the NBP0104 and NBP0103 volume backscatter data from BIOMAPER-II at 120KHz.

Instrument Type

Generic Name: BIo-Optical Multi-frequency Acoustical and Physical Environmental Recorder II

Acronym: BIOMAPERII

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/NETT0007/

Generic Description:

BIOMAPER II is a set of sensors on a long aluminum frame that resembles the tail of a World War II airplane. A research vessel tows the instrument through the water on a specialized tow cable that sends power to the sensors and brings data back to the ship. People use BIOMAPER II to learn about phytoplankton and zooplankton over areas that are too large to study with the traditional net-and-microscope method. Whereas nets can sample areas up to about 5 meters (16 feet) on a side, BIOMAPER II can record data from 500 meters (1,640 feet) or more of the water column at a time. The instrument's standard suite of sensors were chosen for studying plankton: a five-frequency sonar system, a video plankton recorder and an environmental sensor system (ESS, like the one on MOCNESS). The ESS measures water temperature, salinity, oxygen, chlorophyll and light levels. BIOMAPER II also has room for attaching other instruments for specific uses. The instrument's official name is BIOMAPER-II: the BIo-Optical Multi-frequency Acoustical and Physical Environmental Recorder. The Roman numeral II indicates that it's a redesign of the original BIOMAPER, a prototype that was invented and tested in the mid 1990s. (more information).

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
cruiseid	cruise identifier		cruise_id
year	year, e.g. 2001.		year
platform	ship, mooring, fixed location name		platform
timezone	per US GLOBEC, number of hours added to local time to convert to GMT		time_zone
decibel_returns_1	energy backscatter values group 1 of 20, -NN.N represented as NNN	relative decibels	Acc_bksctr
decibel_returns_2	energy backscatter values group 2 of 20, -NN.N represented as NNN	relative decibels	Acc_bksctr
decibel_returns_3	energy backscatter values group 3 of 20, -NN.N represented as NNN	relative decibels	Acc_bksctr
decibel_returns_4	energy backscatter values group 4 of 20, -NN.N represented as NNN	relative decibels	Acc_bksctr

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Database

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Dataset: acoustic backscatter120 kHz