Wednesday and Thursday operations were dedicated to SaVel exercise. This scenario centers on the collection of hydrographic data (CTD) using a LAUV (Xplore-1 and Xplore-2) to study the vertical structure and short-temporal variability of the region of influence of Sado estuary outflow. For that, temperature, salinity, turbidity and chlorophyll data taken from a complete semi-diurnal tidal period (12 h 25 min) is required. The exercise took place along a specific transect in a region close to the navigation channel in the mouth of Sado estuary.
Wednesday was chosen to be a day test mission regarding the high-risk of collision with ships. LAUV paths passes through the navigation channel which is the only connection between Setubal Port and Atlantic Ocean. Main plans and safe protocols were designed and tested along 7 hours considered current and wave forecasts provided by Hidromod.
The big day (literally!) was set up to Thursday. Xplore-1 and Xplore-2 equipped with CTD and other environmental sensors sampled a transect of about 2.8 km, between surface and 20 m depth over 13 hours in a row. Preliminary results seemed impressive and will contribute for better and deeper knowledge about Sado Estuary contribution to the dynamics and hydrographic conditions of its adjacent coastal region.
The vehicles used for the experiment were:
- LAUV-Xplore-2, equipped with an environmental probe measuring temperature, salinity, chlorophyll and turbidity.
- LAUV-Xplore-1, equipped with an environmental probe measuring temperature, salinity, pH and Redox.
The sea state was essential for the success of the exercises. The measured communication ranges were quite stable at 600m for Wi-Fi and more than 2 km for acoustic modem (Xplore-2).