Temperature profiles from expendable bathythermograph (XBT) casts from the NOAA Ship DISCOVERER in the North Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) from 16 July 1976 to 26 October 1976 (NODC Accession 7601856)

XBT data were collected from the NOAA Ship DISCOVERER in support of the Integrated Global Ocean Services System (IGOSS). Data were collected by the US DOC; NOAA; National Ocean Service - Seattle from 16 July 1976 to 26 October 1976. Data were processed by NODC to the NODC standard Universal Bathythermograph Output (UBT) format. Full format description is available from NODC at www.nodc.noaa.gov/General/NODC-Archive/bt.html.

The UBT file format is used for temperature-depth profile data obtained using expendable bathythermograph (XBT) instruments. Standard XBTs can obtain profiles at depths of about 450 or 760 m. With special instruments, measurements can be obtained to 1830 m. Cruise information, position, date, and time are reported for each observation. The data record comprises pairs of temperature-depth values. Unlike the MBT data file, in which temperature values are recorded at uniform 5m intervals, the XBT Data File contains temperature values at non-uniform depths. These depths are at a minimum number of points ("inflection points") required to record the temperature curve to an acceptable degree of accuracy. On output, however, the user may request temperature values either at inflection points or interpolated to uniform depth increments.

本数据集的抛弃式温深计（Expendable Bathythermograph, XBT）数据由美国国家海洋和大气管理局（NOAA）“发现者号”科考船采集，用于支撑综合全球海洋服务系统（Integrated Global Ocean Services System, IGOSS）。数据采集工作由美国商务部（US DOC）、美国国家海洋和大气管理局（NOAA）及国家海洋服务局西雅图分部于1976年7月16日至1976年10月26日期间完成。所有数据均由国家海洋数据中心（National Oceanographic Data Center, NODC）处理为符合NODC标准的抛弃式温深计输出（Universal Bathythermograph Output, UBT）格式。完整格式说明可从NODC官网www.nodc.noaa.gov/General/NODC-Archive/bt.html获取。

UBT文件格式用于存储通过XBT仪器获取的温度-深度剖面数据。标准型XBT可获取约450米或760米深度范围内的剖面数据；搭载专用仪器时，测量深度可达1830米。每条观测记录均包含航次信息、观测位置、观测日期与时间。数据记录由若干组温度-深度值对组成。与机械式温深计（Mechanical Bathythermograph, MBT）数据文件不同——后者的温度值按均匀5米间隔记录，XBT数据文件中的温度值对应非均匀深度。这些深度点为将温度曲线记录至可接受精度所需的最少关键点，即所谓“拐点”。不过在数据输出环节，用户可选择获取拐点处的原始温度值，或通过插值得到均匀深度增量下的温度数据。