Temperature profiles from expendable bathythermograph (XBT) casts from the NOAA Ship MT MITCHELL in the East Coast - US/Canada in support of the Integrated Global Ocean Services System (IGOSS) project for 1973-12-19 (NODC Accession 7400033)

XBT data were collected from the NOAA Ship MT MITCHELL in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the National Ocean Service (NOS) from 19 December 1973 to 19 December 1973. 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.

投弃式温深仪（expendable bathythermograph, XBT）数据由美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）旗下MT MITCHELL号科考船采集，以支撑综合全球海洋服务系统（Integrated Global Ocean Services System, IGOSS）项目。该数据由美国国家海洋服务局（National Ocean Service, NOS）于1973年12月19日至1973年12月19日期间采集，后由国家海洋数据中心（National Oceanographic Data Center, NODC）处理为NODC标准通用温深仪输出（Universal Bathythermograph Output, UBT）格式。完整格式说明可从NODC官网www.nodc.noaa.gov/General/NODC-Archive/bt.html获取。

UBT文件格式适用于通过投弃式温深仪（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；若搭配专用仪器，测量深度可达1830米。每份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-深度值对构成。与机械式温深仪（Mechanical Bathythermograph, MBT）数据文件不同，后者以均匀5米间隔记录温度值，而XBT数据文件中的温度值对应非均匀深度。这些深度为将温度曲线记录至可接受精度所需的最少拐点数量。不过在输出环节，用户可选择按拐点位置或插值至均匀深度间隔的方式获取温度值。