Bathythermograph (XBT), high-resolution CTD/STD, ocean station data from GYRE in the Gulf of Mexico from 1990-10-01 to 1990-10-16 (NCEI Accession 9100028)

The Ocean Station Data; the Water Depth and Temperature Data; and the Conductivity, Temperature and Depth (CTD) was collected from ship GYRE in the Gulf of Mexico by Texas A&M University, College Station, Texas over a two week period between October 1 and October 16, 1990. The originator's data was submitted in two diskettes by Mr David J. Voegele. The data has been converted and is now available on line in C100 Ocean Station Data, C116 bathythermograph (XBT) and F022-CTD-Hi Res file format of NODC.

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 F022 format contains high-resolution data collected using CTD (conductivity-temperature-depth) and STD (salinity-temperature-depth) instruments. As they are lowered and raised in the oceans, these electronic devices provide nearly continuous profiles of temperature, salinity, and other parameters. Data values may be subject to averaging or filtering or obtained by interpolation and may be reported at depth intervals as fine as 1m. Cruise and instrument information, position, date, time and sampling interval are reported for each station. Environmental data at the time of the cast (meteorological and sea surface conditions) may also be reported. The data record comprises values of temperature, salinity or conductivity, density (computed sigma-t), and possibly dissolved oxygen or transmissivity at specified depth or pressure levels. Data may be reported at either equally or unequally spaced depth or pressure intervals. A text record is available for comments.

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