Temperature profiles from expendable bathythermograph (XBT) casts from the USCGC GALLATIN in the North Atlantic Ocean in support of the Integrated Global Ocean Services System (IGOSS) from 11 March 1975 to 05 April 1975 (NODC Accession 7500243)

XBT data were collected from the USCGC GALLATIN in support of the Integrated Global Ocean Services System (IGOSS). Data were collected by the US Coast Guard from 11 March 1975 to 05 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.

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加拉丁号（USCGC GALLATIN），用于支撑全球海洋综合服务系统（Integrated Global Ocean Services System, IGOSS）的运行。数据采集工作由美国海岸警卫队完成，时间跨度为1975年3月11日至1975年4月5日。数据已由国家海洋数据中心（National Oceanographic Data Center, NODC）处理为符合其标准的通用温深仪输出（Universal Bathythermograph Output, UBT）格式。完整的格式说明可从NODC官网的https://www.nodc.noaa.gov/General/NODC-Archive/bt.html页面获取。

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可获取最大深度约450米或760米的温度剖面；若使用专用型号仪器，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、观测日期与时间。数据记录由多组温度-深度数值对构成。与机械式温深仪（Mechanical Bathythermograph, MBT）数据文件不同，后者以固定5米的间隔记录温度数值，而XBT数据文件中的温度数值对应的深度并非均匀分布。这些深度点为以可接受的精度记录温度曲线所需的最少采样点，即“拐点（inflection points）”。在数据输出阶段，用户可选择获取拐点处的原始温度数值，或通过插值得到均匀深度间隔下的温度数据。