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) project from 26 March 1974 to 28 March 1974 (NODC Accession 7400358)

XBT data were collected from the USCGC ACUSHNET in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the US Coast Guard from 26 March 1974 to 28 March 1974. 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ACUSHNET号，服务于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于1974年3月26日至1974年3月28日期间采集完成，后由美国国家海洋数据中心（National Oceanographic Data Center，NODC）按照NODC标准通用温深仪输出（Universal Bathythermograph Output，UBT）格式进行标准化处理。完整的格式说明可通过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投弃式温深仪（XBT）获取的温度-深度剖面数据。标准型XBT可获取约450米或760米深度的剖面数据；若搭载专用仪器，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、日期与时间。数据记录由多组温度-深度数值对构成。与采用均匀5米间隔记录温度值的机械温深仪（Mechanical Bathythermograph，MBT）数据文件不同，XBT数据文件的温度值对应深度并非均匀分布，而是仅记录温度曲线达到可接受精度所需的最少拐点数量。不过在输出环节，用户可选择按原始拐点输出温度值，或通过插值得到均匀深度间隔下的温度数据。