ARISE builds an innovative measurement chain to monitor ammonia releases at sea

The ARISE project is advancing steadily toward its full-scale sea trials, with a critical milestone now underway: the construction and validation of the near-field measurement chain. This complex system is designed to capture key environmental data during the first seconds and minutes following a controlled ammonia release at sea. Data are essential for validating models and informing emergency response strategies.

A modular design

The near-field measurement chain is engineered as a modular network composed of nine floating masts arranged in a 50 by 25 meter grid. These masts are linked by connection lines and floats, forming four identical measurement cells.

One partial cell has already been successfully assembled and tested during a validation campaign in Brest harbour in February 2025.

Each mast is designed to host a combination of:

• Underwater sensors (to track ammonia’s impact on pH, temperature, dissolved oxygen, and conductivity)

• Air sensors (to monitor gas concentrations above the water surface)

• Electronics modules, including power supply, data loggers, and wireless antennas to ensure real-time data transmission

Thanks to a collaborative work under the supervision of Cedre, the instrumentation of the masts has been completed and validated under real conditions.

Successful tests validate the setup

Between February and June 2025, several test campaigns in Brest confirmed the mechanical stability of the structure, the reliability of data acquisition systems, and the effectiveness of wireless communication between underwater probes and surface controllers. This dry-run also provided valuable lessons for the final assembly procedures to be used during the sea trials.

Looking further: Far-field monitoring with drones

While the near-field chain focuses on the immediate release zone, ARISE is also developing a complementary far-field measurement chain. Given the constraints on manned aircraft, the consortium is preparing to deploy autonomous aerial and underwater drones to track ammonia dispersion further away from the release point.

This dual approach ensures comprehensive spatial coverage of the ammonia cloud, regardless of weather conditions, enabling researchers to assess both localized and dispersed impacts with high precision.