Towed Chain of Probes Helps to Investigate Ocean Eddies

Eddies are small scale features in the ocean, but they are essential for mixing processes and the food chain in the sea. Due to their size (50 m – 10 km) and their short lifetime, eddies are difficult to find and even more difficult to investigate.

To track down these small, sub-mesoscale eddies, a chain of multiparameter-probes was developed by Sea & Sun Technology GmbH that can also be pulled by small boats. The towed chain consists of many individual probes (currently max. 25 pieces), which are connected to a cable via a newly developed coupler. A de-pressor at the end of the chain keeps all probes at distinct depths while being pulled through the water. The towed probe chain (TowCTD) is designed as easy to assemble and can be towed through the water with a maximum of 10 knots and carry out high-precision measurements of oceanographic and bio-geochemical properties of the seawater in up to 25 different water depths.

The data are recorded at 10 Hz (every 100 ms) and stored in each probe. Once per second all probes transmit a data set to the deck unit. On board, the data can be loaded via WLAN on any device with a web browser and displayed in various graphics.

In the ocean, it is common to record individual profiles. CTD-rosettes, gliders, AUVs or drifters, all record a one-dimensional profile. In contrast to this, our towed system allows several profiles to be taken at the same time. The temporal interpolation to display a cross-section is not necessary. This makes our TowCTD the first profiling system that simultaneously reproduces two-dimensional data.

Image courtesy Sea & Sun Technology GmbH