Parameters

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

Location

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

Installation
Cruise: SARRADIN Pierre-Marie and MATABOS, Marjolaine, MOMARSAT2022 cruise, Pourquoi Pas?, https://doi.org/10.17600/18001914

Recovery
Cruise: MATABOS Marjolaine (2023) MoMARSAT2023 cruise, RV L'Atalante, https://doi.org/10.17600/18002419

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