Dataset: CTD_MOCNESS1
Deployment: LMG1110

CTD data from MOCNESS tows taken in the Antarctic in 2011

Principal Investigator:

Ann Bucklin (University of Connecticut, UConn - Avery Point)

BCO-DMO Data Manager:

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

Project:

Population ecology of Salpa thompsoni based on molecular indicators (Salp_Antarctic)

Version:

14 January 2014

Version Date:

2014-01-14

Data URL:

https://osprey.bco-dmo.org/dataset-deployment/488874/data

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Description

CTD data collected during the 1 meter2 MOCNESS tows to the Cape Shirreff area in the Antarctic . These data are part of the standard suite of measurements collected during the net tows to provide environmental background for the animals collected.

Fluorescence was not collected during these tows.

Methods & Sampling

Dataset acquisition description

From the MOCNESS Operating Instruction Manual: "The nets are opened and closed sequentially by commands through a single conductor armored cable from the surface. The electronics has 16-bits of resolution and the basic data stream consists of temperature, depth, conductivity, frame angle, flow counts, net number and net response. An acquisition/controller computer retrieves data from the underwater unit at a rate of up to 4 times a second. Temperature (to approximately 0.01 deg C) and conductivity are measured with SEABIRD sensors. A modified T.S.K. flowmeter is normally used to measure flow past the net. Both the temperature and salinity sensors and the flowmeter are attached to brackets which are mounted on the top portion of the frame so that they face directly into the flow when the frame is at a towing angle of 45 deg. An electronic pendulum angle transducer measures the angle of the towed net through the water. A GPS unit providing latitude and longitude [is] integrated into the data stream." (p. 7)

Data Processing Description

Dataset Processing Description

To continue from the MOCNESS Manual: " A microcomputer (together with disk drive and printer) are the deck unit and permit shipboard real-time data acquisition and processing as well as net control. Salinity (to approximately 0.01 ppt), net oblique velocity and vertical velocity, and volume filtered by each net is calculated after each string of data has been received by the computer. Raw and processed data are stored on disc (in separate files) and processed data can be printed out. Plots of net depth versus time, temperature and salinity versus depth, temperature versus salinity and latitude versus longitude are made during a tow and displayed on the computer screen." (p. 7)

Deployment-specific processing description

See pages 33-37 in the Cruise Report for a description of the MOCNESS set up and processing activities on LMG1110.

More information about this dataset deployment

Funding

Award Number	Funding Source
ANT-1044982	NSF Antarctic Sciences

Instruments

CTD MOCNESS

Supplied Description:

"The MOCNESS was provided by Raytheon and it was equipped with nine 335-mesh nets. In addition to the standard temperature and conductivity probes it was also equipped with a beta-type strobe unit provided by BESS Co. and a Benthos 200 kHz altimeter. The underwater unit used through the cruise was #156." p.33 of Cruise Report LMG1110.

Instrument Type

Generic Name: CTD MOCNESS

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/131/

Generic Description:

The CTD part of the MOCNESS includes 1) a pressure (depth) sensor which is a thermally isolated titanium strain gauge with a standard range of 0-5000 decibars full scale, 2) A Sea Bird temperature sensor whose frequency output is measured and sent to the surface for logging and conversion to temperature by the software in the MOCNESS computer (The system allows better than 1 milli-degree resolution at 10 Hz sampling rate), and 3) A Sea Bird conductivity sensor whose output frequency is measured and sent to the surface for logging and conversion to conductivity by the software in the computer (The system allows better than 1 micro mho/cm at 10 Hz sampling rate). The data rate depends on the speed of the computer and the quality of the cable. With a good cable, the system can operate at 2400 baud, sampling all variables at 2 times per second. One sample every 4 seconds is the default, although the hardware can operate much faster. (From The MOCNESS Manual)

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruiseid	cruise identification, e.g. LMG1110, for ARSV Gould cruise 1110		cruiseid
temp	temperature of water	degrees C	temp
datatype	sampling method - instrument type, e.g. MOCNESS-1 or MOCNESS-10		datatype
year	year		year
tow	tow number		tow
day_local	day of month, local, 1-31		day_local
month_local	month of year, local, 1 - 12		month_local
station	station number, from event log		station
yrday_local	year day as a decimal, based on Julian calendar, local	YYY.Y	yrday_local
time_local	time, local, using 24 hour clock to decimal minutes	HHmm.m	time_local
press	depth of observation or sample	decibars	press
potemp	potential temperature or theta¹ ¹Fofonoff and Millard, 1983, UNESCO technical papers in Marine Sciences, #44		potemp
sal	salinity calculated from conductivity, bad values are set to 50		sal
sigma_0	Sigma-theta or potential density¹ ¹Fofonoff and Millard, 1983, UNESCO technical papers in Marine Sciences, #44		sigma_0
angle	angle of net frame relative to vertical (0-89 degrees)	degrees	tow_angle
flow	consecutive flow counts		flow
hzvel	horizontal net velocity	m/min	hzvel
vtvel	vertical net velocity	m/min	vtvel
vol_filt	volume filtered	meters^3	vol_filt
net	MOCNESS net number, (00-08)		net
lat	latitude, negative = South	DD.D	lat
lon	longitude, negative = West	DDD.D	lon
altim	The Altimeter provides data on the altitude of the net systems above the bottom when the net system is closer to the bottom than to the surface.	meters	altimeter

Database

Contribute Data

Dataset: CTD_MOCNESS1
Deployment: LMG1110

Dataset acquisition description

Dataset Processing Description

Deployment-specific processing description

Database

Contribute Data

Dataset: CTD_MOCNESS1Deployment: LMG1110

Dataset acquisition description

Dataset Processing Description

Deployment-specific processing description

Dataset: CTD_MOCNESS1
Deployment: LMG1110