Temperature profiles from expendable bathythermograph (XBT) casts from the NOAA Ship MILLER FREEMAN in the Bering Sea in support of the Integrated Global Ocean Services System (IGOSS) project from 21 March 1977 to 23 March 1977 (NODC Accession 7700266)

XBT data were collected from the 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 21 March 1977 to 23 March 1977. 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.

XBT数据采集自美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）“米勒·弗里曼”号科考船，用于支撑全球海洋综合服务系统（Integrated Global Ocean Services System, IGOSS）项目。该数据由美国国家海洋服务局（National Ocean Service, NOS）于1977年3月21日至1977年3月23日采集完成。数据由美国国家海洋数据中心（National Oceanographic Data Center, NODC）处理为NODC标准通用温深仪输出（Universal Bathythermograph Output, UBT）格式。完整格式说明可通过NODC官网的以下链接获取：www.nodc.noaa.gov/General/NODC-Archive/bt.html。

UBT文件格式用于存储通过抛式温深仪（Expendable Bathythermograph, XBT）获取的温深剖面数据。标准XBT可获取约450米或760米深度的温深剖面；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、观测日期与时间。数据记录由温度-深度值对构成。与MBT数据文件不同——MBT数据文件以5米的均匀间隔记录温度值——XBT数据文件的温度值对应非均匀分布的深度。这些深度点位为将温度曲线记录至可接受精度所需的最少点数，即“拐点”。但在数据输出阶段，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。