Lagrangian Drifter

Status: Contents not yet checked by product owner

Description

The Lagrangian Drifters were designed and built at Helmholtz-Zentrum Hereon to follow the upper surface flow (approx. 50 cm). The main body of the Lagrangian Drifters consists of a 11 cm x 19 cm long tube with a flotation ring at the top. It is attached to a drogue of 35 cm in both length and diameter through a flexible cord within a distance of 10 cm to the tube. When deployed about 5 cm of the tube protrude from the water surface, resulting in a ratio of drag area inside to drag area outside the water of > 20. The tube contains a battery pack and an electronic board, which acquires and reports the collected data via a global satellite network in near real time. Two versions are available of which the simple version only reports date, time and position, at a predefined time interval (e.g. every 5 minutes), which enables to estimate surface current direction and speed. The version 2 measures in addition water temperature, air temperature and atmospheric pressure and can easily be equipped with additional sensors (e.g. salinity).

• 
  Lagrangian Drifter
• 
  Lagranigian Drifter in the field

Measurement Parameters

SENSOR PARAMETER	MANUFACTURER	MODEL	INTERFACE	UNIT	RANGE	ACCURACY	Registry UUID
DATE
TIME
LATITUDE
LONGITUDE
AIR TEMPERATURE	Bosh
WATER TEMPERATURE
ATMOSPERIC PRESSURE	Bosh

Technical Requirements for Operators

Where to install the instrument on the ship?

Lagrangian Drifters are dropped over board underway sailing.

What power supply does the instrument require?

The drifter is powered by 4 x 1.5V D-cell batteries. The power consumption for Version 1 is approx. 20 mW and for Version 2 approx. 30 mW.

What is the size of the instrument?

The size of the main body is 23 x 19 x 19 cm, the drifters underwater sail has a size of 35 x 35 x 35 cm and can be folded to a sheet 35 x 35 x 0.5 cm.

Water proofness

The drifter is water proof up to a water depth of approx. 1 m

What maintenance does the instrument require?

Lagrangian Drifters are typically not recovered. However in case they are recovered they should be cleaned, batteries need to be replaced and test of all sensors should be undertaken.

How will data be transferred?

Data will be automatically transferred via satellite on a predefined schedule e.g. every 5 minutes.

Costs

Upon request by commercial manufacturer Marine Science and Technology

Technichal Details

Will follow soon!

Development status

Technology Readiness Level

TRL 7

Commercial availability

Marine Science and Technology

Contact person: Jan Widera

Autonomous operation

Lagrangian Drifters are fully autonomous after deployment.

Further details

Product experts: Ruben Carrasco, Jochen Horstmann, Alejandro Ordóñez, Michael Streßer (HEREON)