CTD data collected during MOCNESS hauls from ARSV Laurence M. Gould and RVIB Nathaniel B. Palmer cruises LMG0203, NBP0104, and NBP0204 in the Southern Ocean from 2001-2002 (SOGLOBEC project) (NCEI Accession 0278851)

This dataset contains chemical, optical, and physical data collected on ARSV Laurence M. Gould and RVIB Nathaniel B. Palmer during cruises LMG0203, NBP0104, and NBP0204 in the North Atlantic Ocean, South Atlantic Ocean, South Pacific Ocean, and Southern Ocean from 2001-04-30 to 2002-09-11. These data include dissolved Oxygen, light transmission (volts), potential temperature, salinity calculated from CTD primary sensors, sigma-theta, water pressure, and water temperature. The instruments used to collect these data include MOCNESS1 and MOCNESS10. These data were collected by Dr Joseph J. Torres of University of South Florida and Dr Peter H. Wiebe of Woods Hole Oceanographic Institution as part of the "U.S. GLOBEC Southern Ocean (SOGLOBEC)" project and "U.S. GLOBal ocean ECosystems dynamics (U.S. GLOBEC)" program. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2019-03-06.

The following is the text of the dataset description provided by BCO-DMO:

CTD data collected during MOCNESS hauls

Dataset Description:
CTD observations taken simultaneously during MOCNESS tows,
plus MOCNESS sampling conditions

Note: Some variables have been eliminated from the display but are nevertheless available. These variables include: oxycurrent, oxytemp, tempco, and echo.

The MOCNESS is based on the Tucker Trawl principle (Tucker, 1951). The particular MOCNESS system from which these CTD data came is one of two net systems. The MOCNESS-1 has nine rectangular nets (1m x 1.4 m) which are opened and closed sequentially by commands through conducting cable from the surface (Wiebe et al. , 1976). The MOCNESS-10 (with 10 m 2 nets)carries 6 nets of 3.0-mm circular mesh. In both systems, "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 flow meter 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 were collected from four other sensors attached to the frame: the Transmissometer, the Fluorometer, the Down welling light sensor, and the Oxygen sensor. A SeaBird underwater pump was also included in the sensor suite.

It should be noted that due to Antarctic cold, the first few minutes of data are often of questionable value as they are extremely variable and have a high frequency of '50.000' (indicating 'bad values') in the temp, theta and sal fields. Once the sensors encounter deeper, warmer water, they start recording good values.

For additional information, contact the for the cruise.

References

¹Fofonoff 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.

last updated January 10, 2006; gfh