Temperature profiles from expendable bathythermograph (XBT) casts from the USCGC BIBB in the North Atlantic Ocean in support of the Integrated Global Ocean Services System (IGOSS) on 18 September 1977 (NODC Accession 7800069)

XBT data were collected from the USCGC BIBB in support of the Integrated Global Ocean Services System (IGOSS). Data were collected by the US Coast Guard on 18 September 1977. 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.

抛弃式温深计（Expendable Bathythermograph, XBT）数据采集自美国海岸警卫队"比布"号（USCGC BIBB），用于支撑全球综合海洋服务系统（Integrated Global Ocean Services System, IGOSS）。该数据由美国海岸警卫队于1977年9月18日采集完成，后由美国国家海洋数据中心（National Oceanographic Data Center, NODC）按照NODC标准通用温深计输出（Universal Bathythermograph Output, UBT）格式进行标准化处理。完整格式说明可通过NODC官方网站www.nodc.noaa.gov/General/NODC-Archive/bt.html获取。

UBT文件格式用于存储通过抛弃式温深计（XBT）仪器获取的温度-深度剖面数据。标准配置XBT可获取约450米或760米深度的温度剖面；搭配专用拓展仪器时，最大测量深度可达1830米。每份观测数据均附带航次信息、观测位置、观测日期与时间。数据记录由多组温度-深度数值对构成。与温度值按固定5米间隔存储的机械温深计（Mechanical Bathythermograph, MBT）数据文件不同，XBT数据文件中的温度值对应非均匀深度测点。这些测点为将温度曲线记录至可接受精度所需的最少拐点数量。但在数据输出阶段，用户可选择直接输出拐点处的温度值，或通过插值生成均匀深度间隔下的温度数据。