DOI: 10.17882/112307
title: Time-series of ocean bottom currents from seafloor current meters at the Loki's Castle hydrothermal vent field, Arctic Mid-Ocean Ridge (AMOR)

description: This dataset contains ocean bottom current measurements acquired at the Loki's Castle hydrothermal vent site on the Mohn’s Ridge between June 2017 and July 2018 (GS17_TCM3-1; GS17_TCM3-2; GS17_TCM3-3), between June 2019 and July 2020 (GS19_TCM3-1; GS19_TCM3-2), and between July 2021 and September 2021 (GS21_TCM3-2). The data were collected using TCM3 ocean bottom Tilt Current Meters deployed in close proximity to the Loki's Castle vent field.
The TCM3 ocean bottom Tilt Current Meter (Lowell Instruments LLC, North Falmouth, MA, USA) measures current velocity using the drag-tilt principle. The instrument is positively buoyant and anchored to the seafloor via a short flexible tether. Drag generated by moving water tilts the logger in the direction of flow. The internal accelerometer and magnetometer record the magnitude of tilt and the compass bearing, which are used to derive current speed and direction.
Internal clocks were set to UTC prior to deployment. Post-recovery clock drift was not applied to the data files but is documented, when available, in the accompanying metadata file.
Further technical information and instrument specifications are available from the manufacturer (Lowell Instruments LLC) and in the Universal User Guide for the TCM3 Tilt Current Meter (https://lowellinstruments.com/tilt-current-meters/tcm-3-tilt-current-meter/).
For each deployed instrument, the dataset includes two text files:
 - Current data
 - Temperature data
 
## Data organization and naming convention ##
The dataset is organized in a hierarchical structure with one master folder per deployed current meter. Each master folder contains all files associated with a single instrument deployment.
→ Master folder naming convention:
Each master folder follows the naming format: CruiseName_InstrumentType-InstrumentNumber
For example: GS17_TCM3-1
where:
 - GS17 refers to the research cruise (G.O. Sars 2017), combining the vessel name and cruise year.
 - TCM3 refers to the instrument type and model identifier (Tilt Current Meter 3).
 - 1 refers to the specific instrument number or serial number.
This naming convention ensures that each deployment is uniquely and clearly identified by cruise and instrument.
→ Folder structure within each master folder:
Each master folder contains the following subfolders and files:
raw This folder contains the original raw data files in their native formats (e.g., .csv, .txt, .xlsx). Files include current velocities and direction and temperature data. Current measurements have been corrected for magnetic declination. The magnetic declination value applied is documented within the folder and provided in an accompanying .png file. pp_mat This folder contains post-processed data in MATLAB (.mat) format. The data have been quality controlled and trimmed to include only the period during which the instrument was deployed at the seafloor. These files therefore represent the final dataset of scientific interest. figures This folder contains a set of standardized figures generated from the processed data. These figures display the time series and related diagnostics in multiple formats to facilitate quick inspection, quality assessment, and interpretation. photos When available, this folder contains photographs documenting the deployment and/or recovery of the instrument. Sensor metadata logsheet Each master folder also includes a Word document containing the sensor metadata logsheet. This document provides detailed information about the deployment and recovery, including dates, times, geographic coordinates, and relevant instrument configuration details.