Multiple autonomous vehicles applied to detect, track and survey a river plume
River plumes are generated by the flow of buoyant river water into the coastal ocean. They are generally a turbid freshwater feature flowing from land and outside the bounds of an estuary or river channel. The Douro is one of the largest rivers of the Iberian Peninsula, representing the most important freshwater input into the Atlantic on the NW Portuguese coast. Traditional methods of in situ measurements are often complicated and expensive due to the high spatial and temporal variability of its dominant drivers. Up until recently, the general dispersion patterns of the Douro River Plume were mostly studied by numerical models and remote sensing imagery, considering the main drivers involved: river discharge, wind, and tide. The development of accurate and reliable plume monitoring systems is a challenging task. This work reports the recent use of robotic systems to detect, track and survey the Douro Plume front autonomously. These systems can survey this dynamic environment and characterize the frontal regions of the plume regarding salinity and temperature under summer conditions when the plume area is small and mainly tidally driven. Results from several frontal crossings, coincident with satellite imagery acquisitions, demonstrated the AUVs capability to fairly detect the front structure. Cross-frontal exchanges observed by AUVs along the front emphasize the importance of new technologies use on the monitoring and detection of high spatial and temporal dynamical phenomena. Coastal phenomena can constitute a foundation for small, local and opportunistic objective-oriented technological tests. Those intermediary steps between the harbor and offshore operations give the opportunity to engineering and science teams to work together in a stress-free environment.