Temperature profiles from expendable bathythermograph (XBT) casts from the USCGC SHERMAN in the Caribbean Sea and East Coast - US/Canada in support of the Integrated Global Ocean Services System (IGOSS) project from 12 May 1978 to 28 May 1978 (NODC Accession 7800527)

XBT data were collected from the USCGC SHERMAN in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the US Coast Guard (USCG) from 12 May 1978 to 28 May 1978. 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）数据采集自美国海岸警卫队谢尔曼号巡逻舰（USCGC SHERMAN），用于支撑全球海洋综合服务系统（Integrated Global Ocean Services System, IGOSS）项目。数据由美国海岸警卫队（USCG）于1978年5月12日至1978年5月28日期间采集，后由美国国家海洋数据中心（National Oceanographic Data Center, NODC）按照其标准通用温深计输出（Universal Bathythermograph Output, UBT）格式完成标准化处理。完整的格式说明文档可通过NODC官网的https://www.nodc.noaa.gov/General/NODC-Archive/bt.html获取。

UBT文件格式专用于存储通过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米水深的温度剖面；若配备专用仪器，测量水深上限可拓展至1830米。每份观测记录均包含航次信息、站位坐标、观测日期与时间，数据主体由多组温度-深度数值对构成。与机械温深计（Mechanical Bathythermograph, MBT）数据文件不同——后者以每5米的均匀间隔记录温度数值——XBT数据文件中的温度值对应非均匀分布的水深点位。这些点位为记录温度曲线以达到可接受精度所需的最少采样点，即“拐点（inflection points）”。在数据输出环节，用户可自主选择获取拐点处的原始温度数值，或通过插值得到均匀水深间隔下的温度数据。