Temperature profiles from expendable bathythermograph (XBT) casts from NOAA Ship MILLER FREEMAN in the Gulf of Alaska in support of the Integrated Global Ocean Services System (IGOSS) project from 1984-05-29 to 1984-05-30 (NODC Accession 8400116)

XBT data were collected from NOAA Ship MILLER FREEMAN in support of the Integrated Global Ocean Services System (IGOSS) project. Data were collected by the National Ocean Service (NOS) from 29 May 1984 to 30 May 1984. 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）数据采集自美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）“MILLER FREEMAN”号科考船，用于支撑综合全球海洋服务系统（Integrated Global Ocean Services System, IGOSS）项目。该数据由国家海洋服务局（National Ocean Service, NOS）于1984年5月29日至1984年5月30日采集，并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官网www.nodc.noaa.gov/General/NODC-Archive/bt.html查阅获取。

UBT文件格式用于记录通过抛弃式温深计（XBT）仪器获取的温度-深度剖面数据。标准型XBT可获取深度约450米或760米的剖面数据；搭配专用仪器时，测量深度可达1830米。每条观测记录均包含航次信息、站位坐标、观测日期与时间。数据记录由多组温度-深度数值对构成。与MBT数据文件不同——MBT数据文件的温度值以均匀5米间隔记录——XBT数据文件的温度值对应的深度并非均匀分布，仅保留能够以可接受精度还原温度曲线所需的最少点数（即“拐点”）。在数据输出环节，用户可自主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数值。