<title>Data Object ctd_mocness</title>
</pre>
<p>
The MOCNESS is based on the Tucker Trawl principle (Tucker, 1951).  The particular
MOCNESS system from which these CTD data came is one of three 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 <i>et al.</i>, 1976).  The MOCNESS-10 (with 10 m<sup>2</sup> 
nets)carries 6 nets of 3.0-mm circular mesh. The MOCNESS-.25 carries nine 
rectangular nets (1/4-m<sup>2</sup>), usually with 64 micrometer mesh.
In all three 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 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 <i>et al.</i>, 1985)
In addition, data were 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.
</p>

<p>  It should be noted that whenever the data are of questionable value, "50.000" 
is written in the particular data field. 
</p>

<p><u>The following notes are cruise-specific:</u><br>
&nbsp; &nbsp; &nbsp; <b>OC319:</b>  Lats and Lons for first two tows are missing because gps string not
yet available.</p>


<p>Unless otherwise indicated, these data have not been post-processed.</p>

<p>For additional information,
contact the 
<a href="/jg/serv/globec/gb/inventory.html0?project,name_prin">
chief scientist</a> for the cruise or one of the following 
people:
<p align=center>
<table border cellspacing=0 cellpadding=5>
<tr>
<td>MOCNESS &frac14; meter&sup2;</td>
<td>Greg Lough (Gregory.Lough@noaa.gov)</td>
</tr>

<tr>
<td>MOCNESS 1 meter&sup2;</td>
<td>Ted Durbin (edurbin@gsosun1.gso.uri.edu), 
<br>Erich Horgan (ehorgan@whoi.edu), and 
<br>Greg Lough (Gregory.Lough@noaa.gov)</td>
</tr>

<tr>
<td>MOCNESS 10 meter&sup2;</td>
<td>Erich Horgan (ehorgan@whoi.edu)</td>
</tr>
</table>
</p>
<p> <b>Note:</b> Some variables have been eliminated from the display but are 
nevertheless available.  These variables include: oxycurrent, oxytemp, tempco, 
and echo.</p>

<p>
<table border cellspacing=0 cellpadding=5>
<tr><td><b>Field Name</b></td> <td align=center><b>Description</b></td></tr>
<tr><td>	cruiseid</td> <td>Cruise id, e.g. EN261, for Endeavor cruise 
		261</td</tr>
<tr><td>	year_local</td> <td>Local four digit year</td> </tr>
<tr><td>	brief_desc</td> <td>Brief cruise description, such
		as broad-scale, process, mooring,<br>
		 etc., from inventory
		data object</td></tr>
<tr><td>	tow</td> <td>Tow number</td> </tr>
<tr><td>	day_local</td> <td>Local day, 1 - 31</td></tr>
<tr><td>	month_local</td> <td>Local month, 1 - 12</td></tr>
<tr><td>	station</td> <td>station number, from event log</td></tr>
<tr><td>	station_std</td> <td>standard station number, from event
		log</td></tr>
<tr><td>	yrday_local</td> <td>local day and decimal time, 
		starting with Jan.1 as yrday = 1  </td></tr>
<tr><td>	time_local</td> <td>local time using 24 hour clock and
		fractions of the minute.</td></tr>
<tr><td>	press</td> <td>depth, given as - m</td></tr>
<tr><td>	temp</td> <td>temperature degrees C</td></tr>
<tr><td>	theta</td> <td>potential temperature&sup1;</td></tr>
<tr><td>	sal</td> <td>salinity calculated from conductivity.<br>
If salinity exceeds 50 or is less than 0 o/oo, <br>
as it will occasionally do when bad values are encountered or <br>
seawater leaks into the underwater connectors, it is set to 50.</td></tr>
<tr><td>	sigma</td> <td>potential density&sup1;</td></tr>
<tr><td>	fluor</td> <td>fluorescence (0-5 volts)</td></tr>
<tr><td>	angle</td> <td> angle of net frame relative to vertical 
			(0-89 dgrees)</td></tr>
<tr><td>	flow</td> <td>consecutive flow counts</td></tr>
<tr><td>	hzvel</td> <td>horizontal net velocity m/min</td></tr>
<tr><td>	vtvel</td> <td>vertical net velocity m/min</td></tr>
<tr><td>	vol</td> <td>volume filtered (m&sup3;)</td></tr>
<tr><td>	ptran</td> <td>transmissometry or light transmission 
			(0-5 volts)</td></tr>
<tr><td>	oxygen</td> <td>dissolved oxygen (ml/liter)</td></tr>
<tr><td>	lite</td> <td> downwelling light (volts)</td></tr>
<tr><td>	net</td> <td>sequential MOCNESS net number (same
			as "netnum")</td></tr>
<tr><td>	lat</td> <td>latitude</td></tr>
<tr><td>	lon</td> <td>longitude</td></tr>
</table>
<p>
<h2>References</h2>
&sup1;Fofonoff and Millard, 1983, UNESCO technical papers in Marine
	Sciences, #44
</p>
<p>

Tucker, G.H., 1951.  Relation of fishes and other organisms to the scattering
of underwater sound. <i> Journal of Marine Research</i>, <b>10:</b> 215-238.
</p>

<p>
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. <i>Journal of 
Marine Research</i>, <b>34(3):</b> 313-326
</p>
	
<p>
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. <i>Marine Biology</i>, <b>87:</b> 313-323.

</p>
<p>
