On April 8th, our partner Instituto Hidrográfico carried out a WAVY Test Campaign on the north of the Portuguese coast, at Praia do Carneiro.
Praia do Carneiro is the closest of Porto city's beaches to the mouth of the River Douro. The main objective of this campaign was to acquire surface current data from Praia do Carneiro, using the Wavy Littoral, covering the area from the north jetty of the River Douro bar and extending to 500m to the north to Praia dos Ingleses.
The Wavy Littoral, equipped with an antenna and a GNSS receiver (Global Navigation Satellite System), allows the amplification and conversion of radio signals emitted by different satellites, to estimate its position and speed. In addition to the GNSS sensors, it also has non-inertial sensors that make it possible to estimate the wave parameters along its trajectory. The sampling rate is 4 Hz, that is, position and speed data are acquired 4 times per second. All data is stored internally and processed after the recovery of the drifter. Some of this data is sent by GSM to a server and accessible in real-time through a smartphone application. In particular, and for the purpose of recovery, the position of each drifter is displayed every 30 seconds. The Portuguese Institute for Lifesaving used a small vessel and a jet ski from the Portuguese Maritime Authority to deploy and recover the drifters.
The wind was weak to moderate coming from SW, and the wave regime was characterized by waves lesser than 1 meter in height, with periods of 9 seconds. The current, induced mainly by the wind and tide, forced the drifters to move north initially and then towards the coast. During the afternoon deployment, which coincided with the ebb period, the WAVY drifters took an eddy rotating clockwise close to the north Douro jetty head.
Check out the video to observe the WAVY drifters trajectory!