Array of Ocean Bottom Tilt Current Meters: data from the EMSO-Azores observatory, 2022-2023

This dataset contains current data acquired between june 2022 and July 2023 using 5 TCM-3 Ocean Bottom Tilt Current Meters installed next to the Tour Eiffel, hydrothermal vent site and near the SeaMon west station. 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 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 meta data file.

Data are provided for each deployed instrument as two text files:

  • current data
  • temperature data


Physical oceanography


Mid-Atlantic Ridge, EMSO-Azores, EMSO, Hydrothermal Vents, Lucky Strike, Eiffel Tower, Crystal, Montsegur, current velocity, current direction, near seafloor seawater temperature, Time-series, MoMARSAT2022, MoMARSAT2023.


37.290817N, 37.288383S, -32.27543E, -32.28178W



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


  • Regional node: Emso-Azores
  • Site: Lucky Strike hydrothermal field
  • coordinates: see meta data file

Cruise: SARRADIN Pierre-Marie and MATABOS, Marjolaine, MOMARSAT2022 cruise, Pourquoi Pas?,

Cruise: MATABOS Marjolaine (2023) MoMARSAT2023 cruise, RV L'Atalante,

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 meta data file.

Data management

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


47 KoPDF
37 MoCSVRaw data
How to cite
Cannat Mathilde, Gayet Nicolas, Demont Antoine, Fontaine Fabrice, Matabos Marjolaine, Sarradin Pierre-Marie (2024). Array of Ocean Bottom Tilt Current Meters: data from the EMSO-Azores observatory, 2022-2023. SEANOE.

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