CTD data collected during MOCNESS tows to Georges Bank and the Gulf of Maine on the US GLOBEC Georges Bank Broadscale and Process cruises, 1994-1999

<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-10 (with 10 m² nets)carries 6 nets of 3.0-mm circular mesh which are opened and closed sequentially by commands through conducting cable from the surface (Wiebe <em>et al.</em>, 1976). 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 <em>et al.</em>, 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><strong>It should be noted that whenever the data are of questionable value, \"50.000\" is written in the particular data field. </strong></p>

<p><u>The following notes are cruise-specific:</u><br />
<strong>OC319:</strong> 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=\"http://usjgofs.whoi.edu/jg/serv/globec/gb/inventory.html0?project,name_prin\"> chief scientist</a> for the cruise or the <a href=\"http://globec.whoi.edu/globec-dir/contact_dmo.html\">U.S. GLOBEC Data Management Office</a> (DMO).</p>

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

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<h2>References</h2>

<p>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. <em> Journal of Marine Research</em>, <strong>10:</strong> 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. <em>Journal of<br />
Marine Research</em>, <strong>34(3):</strong> 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. <em>Marine Biology</em>, <strong>87:</strong> 313-323.<br />
<em>updated October 27 2005, gfh</em></p>

<p>MOCNESS系统基于塔克拖网原理（Tucker, 1951）。本数据集所用的CTD（温盐深仪，Conductivity, Temperature, Depth）数据源自三套网具系统中的一套MOCNESS系统。MOCNESS-10型（配备10平方米网具）搭载6张孔径为3.0毫米的圆形筛网，可通过水面通过导电电缆发送的指令依次完成开合操作（Wiebe等，1976）。在全部三套系统中，“水下单元每2秒以压缩十六进制格式向甲板单元发送一组数据帧，数据帧包含温度、深度、电导率、网框角度、流量计数、时间、已开网具数量及网具开合状态；随后甲板单元每4秒将数据转发至微型计算机”。温度（测量精度约0.01℃）与电导率由SEABIRD传感器完成采集，常规配置为经过改装的T.S.K.型流量计。温度传感器、电导率传感器及流量计均安装于网框顶部，当网框拖曳角度为45°时，传感器呈水平朝向。计算机每接收一组数据后，即完成盐度（精度约0.01‰S）、位温（θ）、位密（σ）、网具斜向与垂向运动速度，以及单网累计过滤体积的计算（Wiebe等，1985）。此外，网框还搭载了另外四类传感器以采集数据：透射仪、荧光计、下行光传感器及溶解氧传感器。传感器套件中同时集成了海鸟水下泵。</p><p><strong>需特别说明：当数据质量存疑时，对应数据字段将以“50.000”标记。</strong></p><p><u>以下为航次专属说明：</u><br /><strong>OC319航次：</strong>前两次拖曳作业的经纬度信息缺失，原因是当时尚未获取GPS定位字符串。</p><p>若无特别说明，本数据集均未经过后处理。</p><p>如需获取更多信息，请联系<a href="http://usjgofs.whoi.edu/jg/serv/globec/gb/inventory.html0?project,name_prin">本航次首席科学家</a>，或<a href="http://globec.whoi.edu/globec-dir/contact_dmo.html">美国GLOBEC数据管理办公室（U.S. GLOBEC Data Management Office, DMO）</a>。</p><p><strong>补充说明：</strong>部分变量已从显示界面中移除，但仍包含于数据集中，包括oxycurrent、oxytemp、tempco及echo。</p><pre>&nbsp;</pre><h2>参考文献</h2><p>Fofonoff与Millard，1983，联合国教科文组织海洋科学技术报告，第44号。<br />Tucker, G.H., 1951. 鱼类与其他生物对水下声散射的影响，《海洋研究杂志》（*Journal of Marine Research*），第10卷：215-238。<br />Wiebe, P.H.、K.H. Burt、S.H. Boyd、A.W. Morton，1976. 用于浮游动物采样的多网次开合环境感知系统，《海洋研究杂志》（*Journal of Marine Research*），第34卷第3期：313-326。<br />Wiebe, P.H.、A.W. Morton、A.M. Bradley、R.H. Backus、J.E. Craddock、V. Barber、T.J. Cowles及G.R. Flierl，1985. MOCNESS系统的新进展——一种用于浮游动物与小型游泳生物采样的装置，《海洋生物学》（*Marine Biology*），第87卷：313-323。<br /><em>2005年10月27日更新，gfh</em></p>