Lagrangian Ocean Drifters - Surface Current Tracking

Lagrangian Drifter HLD

Affordable drifters for mass deployment of simple measurement devices in a care-free package.

The drifters send their position in regular intervals over satellite. You follow them on a live map; after the campaign we run quality control and hand over the dataset. We take care of data licenses, activation and deactivation, and guide you through the deployment phase.

We offer two versions:

HLD-1 - Standard version with plastic housing
HLD-2 - Eco-friendly version with glass housing, significantly reduced plastic

Both versions share the same specifications and data services. HLD-2 was developed to minimize environmental impact and was deployed in The Ocean Race Europe 2025.

On request we offer pre-deployment planning: deployment positions, avoidance of fishing activity, and drift estimates for your area of interest.

What you see

Your drifters send their position every 5 minutes. The positions accumulate in a database and you get a dataset to derive Lagrangian drift.

How you reach it

Any modern web browser or API. We support different data formats; on request we provide individual APIs and upload routines.

What to be aware of

Trawlers and line-fishers can pick up and destroy drifters. GPS and satellite connection can have outages due to weather, jamming, or coverage gaps. We give you best estimates for your area of interest.

What does the drifter measure?

Lagrangian drift = wind drag + wave breaking + Stokes drift + Eulerian current

Wind drag - negligible due to the 21:1 drogue-to-float ratio
Wave breaking - normally no problem, except in very shallow water
Stokes drift - depends on waves and drogue depth; order cm/s at the surface, decays exponentially with depth
Eulerian current - the background current

Lagrangian means following a particle in space; Eulerian means observing a fixed point. ADCPs and similar instruments are Eulerian in-situ devices, while the actual drift (Stokes plus background current) is obtained with Lagrangian drifters.

Specifications

Parameter	Value
Drogue-to-Float ratio	21:1
Measurement depth	50 cm default, configurable
Position accuracy (GNSS)	10 m
Median update interval	5 min
Duty cycle	approx. 80%
Battery lifetime	up to 150 days, depending on clouds
Float dimensions	20 x 7.5 cm
Drogue dimensions	35 x 35 cm
Operating temperature	-33 to 60 deg C
Data transmission	LEO satellite

What you will get

Lagrangian drifter with glass or plastic housing, pre-assembled
6-month satellite subscription (activation, data, cancellation)
Data processing: outlier removal, timestamp alignment, QC
1-year data storage on our server
Data formats: CSV, MAT, KMZ, netCDF
Live map to follow your drifters
Video tutorials and live support (9-16 CET)

Drifters are reusable - we support battery exchange and reactivation.

Use Cases

Verify and calibrate your HF radar

Due to their cost effectiveness, Lagrangian drifters can be mass deployed to verify or calibrate HF radar measurements.

HF radars measure the current via Bragg scatter of ocean waves of 5 to 50 m, depending on the radar frequency. They observe the dispersion-related current, the background current, and possibly part of the Stokes drift. Current results suggest HF radars follow about one half of the surface Stokes drift, corresponding to an effective measurement depth (doi:10.1175/JTECH-D-21-0025.1).

Map comparing drifter trajectories with HF radar surface currents — Figure 1: Comparing Lagrangian drifters with HF radar data (SOCIB HFR APM Experiment2026 , accessed 12th June 2026)

Stokes drift profiles over drogue depth for four sea states — Figure 2: Stokes drift over drogue depth for a fully developed JONSWAP spectrum, compared with one half of the surface Stokes drift seen by a 12 MHz HF radar

Data Output

Position data (latitude, longitude, UTC timestamp) transmitted in real-time via satellite. No onboard storage.

For other parameters (SST, waves), contact us - we can help you find a suitable device.

FAQ

How long do the drifters last? The drifters are designed for approx. six months of battery time.
What data do the drifters collect? At the moment they record position only. We are working on a new model with air pressure and temperature.
How accurate is the position? The position precision is determined by the GNSS/GPS precision, about 10 m. Propagation of uncertainty over half an hour gives a standard deviation for the velocity of about 1 cm/s.

Background

Our drifter design follows established methods used in peer-reviewed oceanographic research. Selected publications using similar drifter types:

Carlson, D.F., Suzuki, N., Carrasco, R., Filbee-Dexter, K., Gillard, L.C., Myers, P.G., Queirós, A.M., Assis, J., Duarte, C.M., Sejr, M. and Krause-Jensen, D. (2026) “Ocean transport and vertical mixing connect greenland’s macroalgae to deep ocean carbon sinks,” Science of the total environment, 1012, p. 181247. Available at: https://doi.org/https://doi.org/10.1016/j.scitotenv.2025.181247.

Demol, M., Ponte, A.L., Garreau, P., Bellacicco, M., Berta, M., Centurioni, L.R., Doglioli, A.M., Joël, A., Mourre, B. and Pascual, A. (2026) “Large drifter experiment in the western mediterranean sea reveals dynamical versus noise contributions in swot-karin sea level,” Geophysical research letters, 53(10), p. e2025GL121425. Available at: https://doi.org/https://doi.org/10.1029/2025GL121425.

Hans, A.C., Brandt, P., Gasparin, F., Claus, M., Cravatte, S., Horstmann, J. and Reverdin, G. (2024) “Observed diurnal cycles of near-surface shear and stratification in the equatorial atlantic and their wind dependence,” Journal of geophysical research: Oceans, 129(8), p. e2023JC020870. Available at: https://doi.org/https://doi.org/10.1029/2023JC020870.

Miracca-Lage, M., Ménesguen, C., Schmitt, M., Umlauf, L., Merckelbach, L. and Carpenter, J.R. (2025) “Turbulence observations and energetics of diurnal warm layers,” Journal of physical oceanography, 55(11), pp. 2141–2158. Available at: https://doi.org/10.1175/JPO-D-25-0026.1.

Rolland, R., Bouruet-Aubertot, P., Cuypers, Y., Bosse, A., Petrenko, A., Maytie, T., Ponte, A., Barrillon, S., Berta, M., Mourre, B., Pascual, A., Izard, L., Capet, X., Grégori, G., d’Ovidio, F. and Doglioli, A. (2026) “Near-inertial wave trapping inside a fine-scale anticyclonic eddy during the bioswot-med 2023 cruise: Turbulence and energy flux,” Journal of geophysical research: Oceans, 131(3), p. e2025JC022984. Available at: https://doi.org/https://doi.org/10.1029/2025JC022984.

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Interested in our drifters? Contact us for pricing and availability.