Temperature profiles from expendable bathythermograph (XBT) casts from the USCGC BOUTWELL in the North Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) from 11 August 1976 to 10 October 1976 (NODC Accession 7601722)

XBT data were collected from the USCGC BOUTWELL in support of the Integrated Global Ocean Services System (IGOSS). Data were collected by the US Coast Guard from 11 August 1976 to 10 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.

本数据集的投弃式温深仪（expendable bathythermograph，XBT）数据采集自美国海岸警卫队博特韦尔号巡逻舰（USCGC BOUTWELL），旨在支撑全球海洋综合服务系统（Integrated Global Ocean Services System，IGOSS）的运行。数据由美国海岸警卫队于1976年8月11日至1976年10月10日期间采集，经美国国家海洋数据中心（National Oceanographic Data Center，NODC）处理为符合其标准的通用温深仪输出（Universal Bathythermograph Output，UBT）格式。完整格式说明可通过美国国家海洋数据中心官网的https://www.nodc.noaa.gov/General/NODC-Archive/bt.html 查询获取。
UBT文件格式用于存储通过投弃式温深仪（XBT）采集的温度-深度剖面数据。标准型XBT可获取最大深度约450米或760米的剖面数据；若配备专用仪器，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，数据记录由温度-深度值对构成。与机械温深仪（MBT）数据文件不同，后者以5米的均匀间隔记录温度值，而XBT数据文件中的温度值对应的深度并不均匀——这些深度点为以可接受精度记录温度曲线所需的最少拐点数量。在数据输出环节，用户可选择获取拐点处的原始温度值，或通过插值运算得到均匀深度间隔下的温度值。