Low-cost and versatile systems for marine observations
Around 10 years ago, a group of researchers from Galicia in Spain and the North of Portugal were involved in a set of second-stage projects focused on developing an oceanographic observatory of the Iberian Margin. To achieve this, the Portuguese Hydrographic Institute raised the need for an instrument capable of providing data on the littoral drift current. The instrument had to perform well in the zones where waves deform, break and spread. Members of the Faculty of Engineering of the University of Porto came up with the spherical drifter – known as the WAVY drifter. “It performed excellently, clearly disclosing the dynamics in the littoral drift environment, as well as revealed the structure of rip currents. When going aground in the swash zone, its spherical shape facilitated the return to sea with the ‘next’ wave. This was mandatory; otherwise, the measurements would soon be interrupted after a short drift forced by breaking waves,” explains António Jorge da Silva, technical coordinator of the EU-funded MELOA project. Having received positive feedback, the creators pursued developing a bigger, lightweight, low-cost drifter with satellite communications for the open ocean and a smaller one to be used by anyone wishing to make measurements in rivers and estuaries. “This led to the development of the WAVY Ocean and the WAVY Basic in the MELOA project. At the same time, the initial WAVY, now WAVY Littoral, was given the additional capacity to measure waves,” says Jorge da Silva.
Improving current in situ ocean monitoring systems
“The WAVY Ocean is unique in its capacity to effectively measure current in the upper 15 cm of the ocean with negligible direct wind effect and is able to observe waves,” outlines Jorge da Silva. It is also the first drifter with the capacity to observe near-surface temperature gradients. “What’s more, the WAVY Ocean addresses the shallowest sub-layer of the ocean, which available drifters in the market either avoid or, by adopting an equatorial buoyancy, combine with the lowest sub-layer of the atmosphere,” adds Jorge da Silva. As for the WAVY Basic, its purpose was to empower citizens with a tool to scientifically address most features of common concern in environments of easy access, like estuaries. “By acquiring position and temperature in the upper 7 cm of the water column, the WAVY Basic will be an affordable device to observe the dynamics of a tract of an estuary amongst other dynamics,” reports Jorge da Silva.
Adding to the family of surface drifters
However, the project’s ambition was far greater than the WAVY Ocean and WAVY Basic. MELOA also set out to develop two prototypes. The first was the WAVY Ocean-plus, “where a kinetic energy harvester used to capture wave energy for battery charging was added to the WAVY Ocean,” says Jorge da Silva. The second was the WAVY Ocean-Atmo, which is bigger than the WAVY Ocean, floats equatorially and can make observations in the very low atmosphere. Discussing next steps, Jorge da Silva confirms the project is focusing on services made with WAVY Basic and the WAVY Littoral. “We are adding further solutions to the current market of in situ measurement systems for marine environments,” concludes Jorge da Silva. This in turn contributes to the EU’s goals of protecting our natural resources.
Keywords
MELOA, drifter, littoral drift, low-cost drifter, in situ measurement systems, ocean monitoring
