Array of Ocean Bottom Tilt Current Meters: data from the EMSO-Azores observatory, 2016-2017

This dataset contains current data acquired between September 2016 and July 2017 using 2 TCM3 Ocean Bottom Tilt Current Meters installed next to the Tour Eiffel and Montségur hydrothermal vent sites.

The TCM-3 Ocean Bottom Tilt Current Meter from Lowell Instruments LLC (North Falmouth, MA, USA) measures current using the drag-tilt principle. The logger is buoyant and is anchored to the bottom via a short flexible tether. Drag from moving water tilts the logger in the direction of flow. The logger’s accelerometer and magnetometer channels are used to record the amount of tilt and direction of tilt (compass bearing). The array comprised 3 currentmeters, deployed near the Tour Eiffel, Montségur and White Castle hydrothermal vent sites (the instrument at White Castle did not recover data). The array is not connected to an energy node. The currentmeter's internal clocks are set to UTC time before deployment. Clock drift after recovery is not implemented in data but added as metadata in the file "Sites and Sensor metadata".


Mid-Atlantic Ridge, EMSO-Azores, EMSO, Hydrothermal Vents, Lucky Strike, Eiffel Tower, Crystal, Montsegur, current velocity, current direction, near seafloor seawater temperature, Time-series, MoMARSAT2017, MoMARSAT2016


37.30134N, 37.2888S, -32.275618E, -32.27982W



  •  temperature (°C)
  •  current velocity (m/s)
  • current direction (° from N)


  • Regional node: Emso-Azores
  • Site: Lucky Strike hydrothermal field
  • coordinates: see Table_TCM3EMSO_Azores 2016-2017



Operating parameters

For deployments near selected hydrothermal vents at the EMSO-Azores observatory, the accelerometer and magnetometer are configured with a burst interval of 1 minute, a burst rate of 8 Hz and a burst duration of 15 seconds. Temperature are recorded with a period of 1 minute.

Sensor metadata

The specifications of the magnetometer, accelerometer and temperature probes are as follows:

  • magnetometer: 3-axis magnetoresistive sensor and 12-bit A/D Converter, range +/- 1.3 Gauss, accuracy +/- 1° typical (nominal compass bearing), resolution < 0.001 Gauss, maximum recording rate 64 Hz, measurement duration 6 mS
  • accelerometer: 3-axis MEMS Accelerometer and 10-bit A/D Converter, software averaging: up to 32 values per measurement (25 samples per measurement are averaged when recording at 64 Hz), range +/- 2 g, accuracy < 0.01 g (enables 1° inclination determination), resolution < 0.001 g, maximum recording rate 64 Hz, measurement duration 0.625 ms per sample, 32 samples per recorded value (15.6 ms total sample time at 64 Hz 20 ms at 32 Hz or less)
  • thermistor: NTC Thermistor and 16-bit A/D Converter, low-pass filter rejects 50/60 Hz noise, range -5 to 30 °C (standard), -20 to 50 °C (extended), accuracy +/-0.1 °C (standard), +/-0.2 °C (extended), resolution < 0.01 °C, maximum rate 1 Hz, time constant 4 minutes typical (when plunged into an ice bath).

Sensor setup

Test and calibration A set of calibration coefficients for the magnetometer, accelerometer, and temperature channels are stored in the logger. The magnetometer and accelerometer coefficients are unique to each instrument while temperature coefficients are specific to each manufacturing lot. The calibration coefficients are applied upon recovery when the binary data is converted to text data. Data is provided as text, and not corrected for the time drift. Time drift is provided as metadata in Table_TCM3EMSO_Azores 2016-2017.

Data management

  • Real time data transmission: No
  • Data storage in the Communication and storage unit (COSTOF2): No
  • Data storage in the instrument: Full


Current Data TCM3_3
20 MoTEXTRaw data
Temperature data TCM3_3
13 MoTEXTRaw data
Current Data TCM3_1
21 MoTEXTRaw data
Temperature data TCM3_1
13 MoTEXTRaw data
Sensor metadata
54 octetsCSV
Current Data TCM3_1
5 MoNetCDFRaw data
Current Data TCM3_3
5 MoNetCDFRaw data
How to cite
Cannat Mathilde, Wheeler Benjamin, Barreyre Thibaut, Sarradin Pierre-Marie, (2017). Array of Ocean Bottom Tilt Current Meters: data from the EMSO-Azores observatory, 2016-2017. SEANOE.

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