Temperature profiles from expendable bathythermograph (XBT) casts from the USCGC ACUSHNET in the Gulf of Mexico in support of the Integrated Global Ocean Services System (IGOSS) from 07 February 1978 to 09 February 1978 (NODC Accession 7800092)

XBT data were collected from the USCGC ACUSHNET in support of the Integrated Global Ocean Services System (IGOSS). Data were collected by the US Coast Guard from 07 February 1978 to 09 February 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.

投弃式温深计（Expendable Bathythermograph, XBT）数据采集自美国海岸警卫队“阿库什奈特号”（USCGC ACUSHNET），用于支撑全球海洋综合服务系统（Integrated Global Ocean Services System, IGOSS）。数据由美国海岸警卫队于1978年2月7日至1978年2月9日采集，后由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计输出（Universal Bathythermograph Output, UBT）格式。完整格式说明可从NODC官网的https://www.nodc.noaa.gov/General/NODC-Archive/bt.html获取。

UBT文件格式用于存储通过投弃式温深计（XBT）获取的温深剖面数据。标准型XBT可获取深度约450米或760米的温深剖面；若使用专用仪器，测量深度可达1830米。每次观测均记录航次信息、观测位置、日期与时间。数据记录由多组温深值对组成。与机械式温深计（Mechanical Bathythermograph, 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点数（即“拐点”）。但在输出时，用户可选择获取拐点处的原始温度值，或是将数据插值为均匀深度步长后的温度值。