Temperature profiles from expendable bathythermograph (XBT) casts from the R/V TRIDENT in the South Pacific Ocean in support of the Integrated Global Ocean Services System (IGOSS) project from 07 April 1975 to 19 April 1975 (NODC Accession 7600703)

XBT data were collected from the R/V TRIDENT in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the University of Rhode Island (URI) from 07 April 1975 to 19 April 1975. 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）数据由“TRIDENT”号科研考察船采集，用于支撑全球海洋综合服务系统（Integrated Global Ocean Services System, IGOSS）项目。罗德岛大学（University of Rhode Island, URI）于1975年4月7日至1975年4月19日完成了该数据的采集工作。数据由美国国家海洋数据中心（National Oceanographic Data Center, NODC）按照其标准通用温深计输出格式（Universal Bathythermograph Output, UBT）进行处理。完整的格式说明可从NODC官网获取，链接为：www.nodc.noaa.gov/General/NODC-Archive/bt.html。

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。标准型XBT可获取最大深度约450米或760米的剖面数据；若使用特制仪器，则可将测量深度拓展至1830米。每份观测记录均包含航次信息、观测位置、观测日期与时间。数据记录由温度-深度值对组成。与机械温深计（Mechanical Bathythermograph, MBT）数据文件不同——后者以固定5米间隔记录温度值，XBT数据文件中的温度值对应非均匀分布的深度。这些深度点为记录温度曲线以达到可接受精度所需的最少点数（即“拐点”）。但在数据输出时，用户可选择获取拐点处的原始温度值，或通过插值得到均匀深度间隔下的温度值。