Editing Lagrangian Drifter (section)

== 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). <gallery mode="packed-hover">
File:Lagrangian Drifter.jpg|Lagrangian Drifter
File:Lagrangian Drifter 2.jpg|Lagranigian Drifter in the field
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