L4 Scientific Buoy

As part of the NERC Oceans 2025 programme in 2007, PML were awarded a capital grant to build autonomous buoys for the long-term stations at L4 and E1. In 2020 PML were awarded funding through the European Regional Development Fund to deliver innovation support to Devon based industries, which included funds for a new buoy platform at the L4 station.

The buoy has been upgraded to a 4 m diameter platform which stands over 5m above the sea surface. The buoy has been designed and built to have high power generation and plug and play capability for sensor integration. A significant upgrade is the autonomous water column profiling capability, which deploys a sensor payload through the water column at pre-determined intervals. This capability exists on only a handful of platforms in the world and certainly unique in the UK.

Power:

800 Watts of Solar panels and two 350 W wind turbines, which charge 1000 Ah battery storage.

Communications:

Steatite Wave Relay meshed network, which provides high bandwidth connectivity between PML and the buoy.

Measurements:

Profiling measurements include sea temperature, salinity (calculated from Conductivity), depth, dissolved Oxygen, Chlorophyll a, turbidity, and Coloured Dissolved Organic Material (CDOM).

Surface measurements include pH, pCO2, atmospheric CO2 analyser, Ultrasonic 3D wind speed and direction sensor, water column currents (measured via ADCP, both on the buoy and on the seabed close to the L4 station), wave data, and a small volume water sampler (150ml x 24 bottles)

Atmospheric Measurements:

A Met Office weather sensor measuring air temperature, humidity, wind speed and direction, atmospheric pressure, sunlight intensity (PAR)

The L4 buoy has been designed and is available to use as a platform for technological development. PML has a long history of working with academia and industry to develop and test new senor technologies and the L4 buoy is an ideal test platform.