Dataset: MOCNESS CTD tows

MOCNESS CTD

 Methodology: none provided with data
 
 Change history: YYMMDD
    070626: downloaded original merged data from EDDIES data web site;
    071206: prepared for OCB database by Nancy Copley (OCB DMO)
    090828: added to database by Cyndy Chandler (OCB DMO)
    100630: Cruise 415-1 tow 12 had some bad position data  (found with stats)

            OC415-1	12	189.592674	20050708	1413	687
            30.8667	0.0667 replaced with position data from previous record
            30.879	-66.3008

            OC415-1	12	189.564873	20050708	1333	19
            30.8962	-56 replaced with position data from previous record
            30.8962	-66.2867
 

 The following notes apply to both OC415-1 and OC415-3:

 CTD sensor metadata for MOCNESS tows: m_415_17 through m_415_28 
 Temperature Probe #  1678  Conductivity Probe #  199
 Pressure Probe #  105      Oxygen Probe #  130349
 Transmissometer #  243     Fluorometer #  1


 To view the final data acquisition screen for each MOCNESS tow:

Unless otherwise indicated, these data have not been post-processed, and include some bad lat/lon points. Bad positions are fixed as they are identified. Original raw MOCNESS tow CTD data MOCNESS tow CTD files (123 MB) MOCNESS tow CTD files (90 MB) For additional information, contact the chief scientist for the cruise or data set PI. Parameter Description Units

Cruise_ID Cruise identification, dimensionless e.g. OC415-1, for Oceanus cr. 415, leg 1 tow MOCNESS tow number dimensionless date_local 8 digit year month day, local time YYYYMMDD yrday_local year day, Julian Calendar local time decimal day time_local time of day; local time using 24 hour clock. HHmm.m lat latitude, negative = South decimal degrees lon longitude, negative = West decimal degrees press depth of sample meters echo unknown unknown temp temperature degrees C. potemp potential temperature (1) degress C. sal salinity calculated from conductivity; dimensionless if salinity exceeds 50 or is less than 0 o/oo, salinity is set to 50. sigma_0 potential density(1) at the surface kg/m3-1000 angle angle of net frame relative to degrees vertical (0-89 dgrees) flow consecutive flow counts counts hzvel horizontal net velocity m/min meters/minute vtvel vertical net velocity m/min meters/minute vol volume filtered meters^3 net sequential MOCNESS net number integer fluor fluorescence (0-5 volts) volts trans_V light transmission (0-5 volts) volts oxycurrent oxygen sensor current oxytemp oxygen sensor temperature oxygen oxygen; dissolved milliliters/liter nd indicates missing or no data Background information provided by DMO: The MOCNESS is based on the Tucker Trawl principle (Tucker, 1951). The particular MOCNESS system from which these CTD data came is the MOCNESS-1 which has nine rectangular nets (1m x 1.4 m) that are opened and closed sequentially by commands through conducting cable from the surface (Wiebe et al., 1976). "The underwater unit sends a data frame, comprised of temperature, depth, conductivity, net-frame angle, flow count, time, number of open net, and net opening/closing, to the deck unit in a compressed hexadecimal format every 2 seconds and from the deck unit to a microcomputer every 4 seconds... Temperature (to approximately 0.01 deg C) and conductivity are measured with SEABIRD sensors. Normally, a modified T.S.K.-flowmeter is used... Both the temperature and conductivity sensors and the flowmeter are mounted on top of the frame so that they face horizontally when the frame is at a towing angle of 45deg... Calculations of salinity (to approximately 0.01 o/oo S), potential temperature (theta), potential density (sigma), the oblique and vertical velocities of the net, and the approximate volume filtered by each net are made after each string of data has been received by the computer." (Wiebe et al., 1985) In addition, data may be collected from four other sensors attached to the frame: the Transmissometer, the Fluorometer, the Downwelling light sensor, and the Oxygen sensor. A SeaBird underwater pump was also included in the sensor suite. References (1) Fofonoff and Millard, 1983, UNESCO technical papers in Marine Sciences, #44 Tucker, G.H., 1951. Relation of fishes and other organisms to the scattering of underwater sound. Journal of Marine Research, 10: 215-238. Wiebe, P.H., K.H. Burt, S. H. Boyd, A.W. Morton, 1976. The multiple opening/closing net and environmental sensing system for sampling zooplankton. Journal of Marine Research, 34(3): 313-326 Wiebe, P.H., A.W. Morton, A.M. Bradley, R.H. Backus, J.E. Craddock, V. Barber, T.J. Cowles and G.R. Flierl, 1985. New developments in the MOCNESS, an apparatus for sampling zooplankton and micronekton. Marine Biology, 87: 313-323.