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This along track (JGOFS) data set was obtained primarily by applying calibrations to raw data and decimating to whole minute intervals. Several fields are derived measurements from more than an single raw input. For example, Course Made Good (cmg) and Speed Over Ground (sog) are calculated from gyro and GPS inputs.
Cruises often used "9.99" or "9999" to indicate bad data. Those numbers were changed to 'nd'. Not all bad data were flagged in this way however. Users of these data are encouraged to read the Data Report (found at the Directory Level of this system under "Inventory" then under "project/cruise id", and then under "data report") in order to be aware of bad data points that are not indicated by "9"s and therefore remain in the dataset.
Questions regarding this data set should be directed to: Bob Groman GLOBEC Data Management Office Woods Hole Oceanographic Inst. Woods Hole, MA 02543
Phone: 508 548 1400 E-mail: rgroman@whoi.edu
Last updated March 15, 2006
Along track data, including CTD, MET and navigation information.
This along track (JGOFS) data set was obtained primarily by applying calibrations to raw data and decimating to whole minute intervals. Several fields are derived measurements from more than an single raw input. For example, Course Made Good (cmg) and Speed Over Ground (sog) are calculated from gyro and GPS inputs.Cruises often used '9.99' or '9999' to indicate bad data. Those numbers were changed to 'nd'. Not all bad data were flagged in this way however.
Version 2: Some erroneous coordinates were discovered. The latitude and longitude values 999.99 and 0.0000 were changed to 'nd' to indicate bad data. Added ISO_DateTime_UTC field.
An anemometer is a device for measuring the velocity or the pressure of the wind.
An anemometer is a device for measuring the velocity or the pressure of the wind. It is commonly used to measure wind speed. Aboard research vessels, it is often mounted with other meteorological instruments and sensors.
A barometer is an instrument used to measure atmospheric pressure.
A barometer is an instrument used to measure atmospheric pressure. There are many types of barometers identified by make and model and method of measurement.
Used to measure the water depth.
A single-beam echo sounder is an instrument that measures water depth at a single point below the platform by timing pulses of sound reflected on the seafloor. The echo sounder transmits and receives sound, accurately measuring the time it takes to leave the sounder, reach the bottom and return to the sounder. It then converts this information into digital or graphic representations of the bottom depth and relief. The average echo sounder consists of a transmission and reception unit that sends sound signals through the water, receives and decodes information and converts that information into either a graphic or visual form. Attached to the receiver is a transducer that acts as a microphone and a speaker under the water. Sound waves travel at approximately 1500 m/s through the water dependent on water temperature". more from LMS Technologies
The Eppley Precision Infrared Radiometer (PIR) pyrgeometer measures longwave (infrared) radiation. It is housed in a weatherproof titanium canister that has been painted with a very flat black paint that absorbs radiation. A small glass dome at the top of the instrument is covered with an 'interference coating' which allows only infrared radiation to come through. Light levels are detected as temperature changes creating voltages in fine wire coil detectors. more from Eppley Labs
Sea surface fluorometer readings in voltages, (range 0-5)
A fluorometer or fluorimeter is a device used to measure parameters of fluorescence: its intensity and wavelength distribution of emission spectrum after excitation by a certain spectrum of light. The instrument is designed to measure the amount of stimulated electromagnetic radiation produced by pulses of electromagnetic radiation emitted into a water sample or in situ.
used to measure relative humidity and/or wet temperature.
Hygrometers are used for measuring relative humidity. This term is used when details of the make, model number and measurement principle are not known.
Photosynthetically Available Radiation 400-700nm (PAR), sensor package mounted on ship's science mast. BSI QSR-240
A PAR sensor measures photosynthetically available (or active) radiation. The sensor measures photon flux density (photons per second per square meter) within the visible wavelength range (typically 400 to 700 nanometers). PAR gives an indication of the total energy available to plants for photosynthesis. This instrument name is used when specific type, make and model are not known.
Used to measure long wave radiation. Eppley PSP
This radiometer measures sun and sky irradiance in the range of wavelengths 0.285 to 2.8 microns, including most of the solar spectrum. The PSP is intended to weight the energy flux in all wavelengths equally. It is a "hemispheric receiver" intended to approximate the cosine response for oblique rays. The Eppley Precision Spectral Pyranometer (PSP) is primarily used where high accuracy is required or where it is used to calibrate other pyranometers. The PSP outputs a low level voltage ranging from 0 to a maximum of about 12mV depending on sensor calibration and radiation level. An instruction manual provided by Eppley contains the sensor calibration constant and serial number. The Precision Spectral Pyranometer is a World Meteorological Organization First Class Radiometer and comes with a calibration certificate traceable to the World Radiation Reference and a temperature compensation curve. More information is available from Eppley Labs.
Thermosalinograph used to obtain a continuous record of sea surface temperature and salinity.
A thermosalinograph (TSG) is used to obtain a continuous record of sea surface temperature and salinity. On many research vessels the TSG is integrated into the ship's underway seawater sampling system and reported with the underway or alongtrack data.
Cruise id, e.g. NBP0202, for Nathaniel B. Palmer cruise 0202
month, day, year (GMT time) e.g. mar18 2002, format: MMMdd_yyyy
time GMT, 24 hour clock
Latitude, negative = South
Longitude, negative = West
Speed over ground
Horizontal Dilution of Position is an indicator of the precision of the GPS measurement. The lower the number, the more precise the position.
The ship's heading, measured by the Gyroscope.
Course made good: the course actually achieved on the chart (map), after making allowances for wind direction and currents.
downwelled Photosynthetically Available Radiation 400-700nm (PAR), sensor package mounted on ship's science mast.
Sea surface temperature
Sea surface conductivity
Sea surface salinity
Depth of water, uncorrected
Wind speed (true, corrected for ship motion)
Wind direction (true, corrected for ship motion)
Air temperature
Relative humidity
Barometric pressure
long wave radiation, using a Precision Infrared Radiometer
short wave radiation, using a Precision Spectral Pyranometer
Jan. 1 = yrday 0. GMT day and decimal time, as 325.5 for the 326th day of the year, or November 22 at 1200 hours (noon).
year in format yyyy
Date and time following ISO8601 convention.
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