Dataset: CTD_MOCNESS1
Deployment: EN487

MOCNESS CTD data from the Gulf of Maine Krill project

Principal Investigator:

Gareth Lawson (Woods Hole Oceanographic Institution, WHOI)

Co-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:

Biological and Physical Determinants of Euphausiid Aggregation, Behavior, and Interaction with Higher Predators at an Abrupt Topographical Feature in the Gulf of Maine (Krill GoME)

Current State:

Final no updates expected

Version:

20120229

Deployment Synonyms:

Krill

Version Date:

2012-02-29

Data URL:

https://osprey.bco-dmo.org/dataset-deployment/455038/data

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Description

CTD data collected during the 1 meter2 MOCNESS tows for three cruises in 2010 to the Gulf of Maine and Georges Bank. These data provide standard environmental measurements simultaneously with the collection of the animals.

Fluorescence, oxygen and irradiance data were not collected on these cruises.

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)

Deployment-specific acquisition description

Both the VPR and MOCNESS were deployed via the stern A-frame using winch #2. Although the VPR is autonomous and does not require conducting cable, for this cruise we had borrowed Dr. Mark Baumgartner’s VPR, which includes a full CTD. We therefore wired up this CTD through the winch in order to get real-time information on depth and altitude, and to use (or try to use) Mark’s bottom switch. This required some initial fiddling with baudrate and sampling intervals, but communication worked fine.

The MOCNESS communicated with the deck unit fine with the ca. 10,000m of wire on winch #2.

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)

See data objects mocness_tabs and mocness_logs for explicit processing information for each tow.

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-0928801	NSF Division of Ocean Sciences

Instruments

CTD MOCNESS

Supplied Description:

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. NBP0202, for RVIB Palmer cruise 0202		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	meters	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	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<sup>3</sup>	vol_filt
net	MOCNESS net number, (00-08)		net
lat	latitude, negative = South	DD.D	lat
lon	longitude, negative = West	DDD.D	lon

Database

Contribute Data

Dataset: CTD_MOCNESS1
Deployment: EN487

Dataset acquisition description

Deployment-specific acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: CTD_MOCNESS1Deployment: EN487

Dataset acquisition description

Deployment-specific acquisition description

Dataset Processing Description

Dataset: CTD_MOCNESS1
Deployment: EN487