Temperature profile data collected using XBTs from the PRESIDENT MADISON from the Pacific Ocean during the Thermal Structure Monitoring Program in the Pacific (TRANSPAC) project, 20 November 1976 to 28 November 1976 (NODC Accession 8100128)

Temperature profile data were collected using bathythermograph (BT/XBT) casts from PRESIDENT MADISON in the Pacific Ocean from November 20, 1976 to November 28, 1976. Data were submitted by Scripps Institution of Oceanography in part of the Thermal Structure Monitoring Program in the Pacific (TRANSPAC) project. Data were processed by NODC to the NODC standard Universal Bathythermograph Output (UBT) format. Full BT descriptions are available at http://www.nodc.noaa.gov/General/NODC-Archive/bt.html.

The UBT format contains temperature-depth profile data obtained using expendable bathythermograph (XBT) instruments. Cruise information, position, date and time were reported for each observation. The data record was comprised of pairs of temperature-depth values. Unlike the MBT Data File, in which temperature values were recorded at uniform 5 m intervals, the XBT data files contained temperature values at non-uniform depths. These depths were recorded at the minimum number of points (''inflection points'') required to accurately define the temperature curve. Standard XBTs can obtain profiles to depths of either 450 or 760 m. With special instruments, measurements can be obtained to 1830 m.

本数据集的温度剖面数据采集自1976年11月20日至28日期间，在太平洋海域执行任务的“总统麦迪逊”号，采用海水温度深度剖面仪（bathythermograph，BT/XBT）投放观测方式获取。数据由斯克里普斯海洋研究所作为太平洋热结构监测计划（TRANSPAC）项目的组成部分提交。美国国家海洋数据中心（NODC）将所有数据处理为符合NODC标准的通用海水温度深度剖面仪输出（Universal Bathythermograph Output，UBT）格式。有关BT的完整说明可访问：http://www.nodc.noaa.gov/General/NODC-Archive/bt.html。
UBT格式包含通过投弃式海水温度深度剖面仪（expendable bathythermograph，XBT）获取的温度-深度剖面数据。每条观测记录均附带航次信息、观测位置、日期与时间，数据记录由多组温度-深度数值对构成。与机械海水温度深度剖面仪（MBT）数据文件不同，后者的温度值以均匀5米的间隔记录，而XBT数据文件的温度值对应的深度并不均匀——这些深度仅记录了精准刻画温度曲线所需的最少数量的点，即“拐点”。标准XBT设备可获取的剖面最大深度为450米或760米，若使用专用仪器，测量深度可达1830米。