Improving path-planning for glider operations: A current-forecast based approach applied in the Gulf of St. Lawrence

Ocean gliders are a key platform that can fill the gaps between coastal and open ocean observing systems, between Argo floats, and moorings and ship-based strategies (Testor et al., 2019). One challenge for these slow-moving, primarily underwater systems, is to improve waypoint-based navigation to minimize the effects of wind and current driven dynamics. This is important in time-critical applications where there are advantages in reaching a site as quickly as possible, for example when monitoring storm systems or tracking eddies. Optimal path planning will also be important in long duration missions where battery consumption is a limiting factor of the deployment. In August 2019, a Slocum glider was deployed in the Gulf of St. Lawrence for preliminary system studies. During the deployment, a waypoint planning system was used to generate the glider waypoints list files. In this presentation, we will present the design of the path-planning system and show in-situ scientific measurements collected by the glider. The key optimized value assigned to enable path planning are minimizing current speeds and the key metric for validating the performance is the distance covered per hour. This approach has tremendous value for improving the autonomy of gliders in operational ocean monitoring applications, removing pressure from pilots managing the glider mission and improving the state-of-the-art of ocean data products.