Temperature profiles from expendable bathythermograph (XBT) casts from the NOAA Ship ALBATROSS IV in the North Atlantic Ocean in support of the Integrated Global Ocean Services System (IGOSS) from 15 February 1975 to 21 May 1976 (NODC Accession 7601744)

XBT data were collected from the NOAA Ship ALBATROSS IV in support of the Integrated Global Ocean Services System (IGOSS). Data were collected by the National Marine Fisheries Service (NMFS) from 15 February 1975 to 21 May 1976. 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.

本数据集的抛弃式深海测温仪（expendable bathythermograph，XBT）数据由美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration，NOAA）“信天翁IV号”科考船采集，以支持综合全球海洋服务系统（Integrated Global Ocean Services System，IGOSS）的相关工作。数据由美国国家海洋渔业局（National Marine Fisheries Service，NMFS）于1975年2月15日至1976年5月21日期间采集完成，后由国家海洋数据中心（National Oceanographic Data Center，NODC）处理为NODC标准通用温深计输出（Universal Bathythermograph Output，UBT）格式。完整格式说明可通过NODC官方网站www.nodc.noaa.gov/General/NODC-Archive/bt.html获取。

UBT文件格式用于存储通过XBT仪器获取的温度-深度剖面数据。标准型XBT可获取深度约450米或760米的温度剖面；搭载专用仪器时，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-深度值对构成。与机械式深海测温仪（MBT）数据文件不同，MBT数据文件以均匀5米间隔记录温度值，而本XBT数据文件的温度值对应非均匀深度测点。这些测点为以可接受精度完整记录温度曲线所需的最少“拐点”。不过在数据输出环节，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值。