Temperature profiles from expendable bathythermograph (XBT) casts from the USCGC MELLON in the North Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 20 July 1973 to 15 September 1973 (NODC Accession 7301114)

XBT data were collected from the USCGC MELLON in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the US Coast Guard (USCG) from 20 July 1973 to 15 September 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.

本数据集的投弃式海水深度温度计（Expendable Bathythermograph，XBT）数据采集自美国海岸警卫队梅隆号巡逻舰（USCGC MELLON），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（United States Coast Guard，USCG）于1973年7月20日至1973年9月15日期间采集，后由国家海洋数据中心（National Oceanographic Data Center，NODC）处理为NODC标准通用海水深度温度计输出（Universal Bathythermograph Output，UBT）格式。完整格式说明可从NODC官网获取：www.nodc.noaa.gov/General/NODC-Archive/bt.html。

UBT文件格式用于存储通过XBT获取的温深剖面数据。标准型XBT可获取约450米或760米深度的温深剖面；配备专用仪器时，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，数据记录由一组组温深数值对构成。与以5米等间隔记录温度的机械式海水深度温度计（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——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”）。但在数据输出时，用户可选择获取拐点处的温度值，或通过插值得到等深度间隔的温度数据。