BATHYTHERMOGRAPH (XBT) from multiple German platforms from 19730101 to 19831231 (NCEI Accession 8400184)

Ocean Station Data and Bathythermograph (XBT) data were collected from Helgoland Biological Stations using multiple German ships (ANTON DOHRN, GAUSS, FRIEDRICH HEINCKE, WALTHER HERWIG, METEOR, POSEIDON and SOLEA). The data was collected between January 1, 1973 to December 31, 1983 by Helgoland Biological Stations, Deutsches Hydrographische Institut, and Deutsches Ozeanographisches Datenzentrum.

Data has been processed by NODC to the NODC standard Bathythermograph (MBT) (C128), Bathythermograph (XBT) (C116), and Ocean Station (C100) formats.

The Oceanographic Station Data (C100) format contains physical-chemical oceanographic data recorded at discrete depth levels. Most of the observations were made using multi-bottle Nansen casts or other types of water samplers. A small amount (about 5 percent) were obtained using electronic CTD (conductivity-temperature-depth) or STD (salinity-temperature-depth) recorders. The CTD/STD data were reported to NODC at depth levels equivalent to Nansen cast data, however, and have been processed and stored the same as the Nansen data. Cruise information (e.g., ship, country, institution), position, date, and time, and reported for each station. The principal measured parameters and temperature and salinity, but dissolved oxygen, phosphate, total phosphorus, silicate, nitrate, nitrite, and pH may be reported. Meteorological conditions at the time of the cast (e.g., air temperature and pressure, wind, waves) may also be reported, as well as auxiliary data such as water color (Forel-Ule scale), water transparency (Secchi disk depth), and depth to bottom. Values of density (sigma-t) sound velocity, and dynamic depth anomaly are computed from measured parameters. Each station contains the measurements taken at the observed depth levels, but also includes data values interpolated to a set of standard depth levels.

The C116/C118 format contains temperature-depth profile data obtained using expendable bathythermograph (XBT) instruments. Cruise information, position, date and time were reported for each observation. The data record was comprised of pairs of temperature-depth values. Unlike the MBT Data File, in which temperature values were recorded at uniform 5 m intervals, the XBT data files contained temperature values at non-uniform depths. These depths were recorded at the minimum number of points ("inflection points") required to accurately define the temperature curve. Standard XBTs can obtain profiles to depths of either 450 or 760 m. With special instruments, measurements can be obtained to 1830 m. Prior to July 1994, XBT data were routinely processed to one of these standard types. XBT data are now processed and loaded directly in to the NODC Ocean Profile Data Base (OPDB). Historic data from these two data types were loaded into the OPDB.

The C128 format is used for temperature-depth profile data obtained using the mechanical bathythermograph (MBT) instrument. The maximum depth of MBT observations is approximately 285 m. Therefore, MBT data are useful only in studying the thermal structure of the upper layers of the ocean. Cruise information, date, position, and time are reported for each observation. The data record comprises pairs of temperature-depth values. Temperature data in this file are recorded at uniform 5 m depth intervals.

Tags: oceanography
Organization: National Oceanic and Atmospheric Administration, Department of Commerce