World Ocean Database 2009: Expendable Bathythermograph Data (XBT)

World Ocean Database 2009 (WOD09) is a scientifically quality-controlled database of selected historical in-situ surface and subsurface oceanographic measurements produced by the Ocean Climate Laboratory (OCL) at the National Oceanographic Data Center (NODC), Silver Spring, Maryland, USA. WOD09 updates and expands on an earlier version of the World Ocean Database 2005 (WOD05) product by including new data and implementation of the ISO 3166-1 country code standards in the cruise identifier. Data are both historical and modern with the most recent data from 2008. WOD09 was created to provide the full set of data and quality control procedures used to calculate climatologies of temperature, salinity, oxygen, phosphate, silicate, and nitrate to produce the World Ocean Atlas 2009 (WOA09). The WOD09 database includes oceanographic variables measured at “observed” depth levels as well as interpolated to a set of 33 “standard” depth levels.

The data are stored in 11 datasets (Ocean Station Data – OSD; High-resolution Conductivity-Temperature-Depth – CTD; Mechanical/Digital/Micro Bathythermograph – MBT; Expendable Bathythermograph – XBT; Surface – SUR; Autonomous Pinniped Bathythermograph – APB; Moored Buoy – MRB; Profiling Float – PFL; Drifting Buoy – DRB; Undulating Oceanographic Recorder – UOR; and Glider – GLD) each one representing a group of similar oceanographic probes.

APDRC only serves the geographically sorted OSD, CTD and XBT datasets at both the observed and standard depth levels. The WOD includes quality control flags that are set during automatic and subjective quality control steps in the calculation of WOA09 climatologies. There are quality control flags with each measurement and for each profile; and are provided here. The quality control flags for each depth of measurement are also served here. For the different quality flags (qf) please refer Table 12 in the WOD09 documentation at ftp://ftp.nodc.noaa.gov/pub/WOD09/DOC/wod09readme.pdf.

Expendable Bathythermograph (XBT) Data

The XBT was first deployed around 1966 and replaced the MBT in most measurement programs. XBT probes are torpedo-shaped devices attached to a spool of copper wire. The instrument is launched over the side of a moving ship, from an airplane, or from a submarine. Temperature is estimated by measurements of the resistance in a semi-conductor (called a thermistor). For recording the information is sent back to the command unit over the copper wire. Depth is calculated as a function of time since launch using a manufacturer-supplied equation.

Variables
Temperature (degC)
Zonal Station data
Meridional Station data
VerticalObserved and standard levels  
Temporal Historical to 2008
Static?yes
VolumeOver two million profiles
Serverpublic:
Sourcehttp://www.nodc.noaa.gov/OC5/WOD09/pr_wod09.html 
Acquired Jan 18, 2006 (Updated Nov 2011)
APDRC contact
Supplementshttp://www.nodc.noaa.gov/OC5/WOD09/docwod09.html