Integration of Additional Products into the Sargassum Seaweed Tracker

Mats of Sargassum seaweed washing on shore is becoming a common occurrence in the Caribbean. CARICOOS, the ocean observing system for Puerto Rico and the Virgin Islands has developed a Sargassum tracking tool based upon surface current forecasts from the AMSEAS ocean model and surface current measurements from their High Frequency radar network. The ocean model has shown skill in predicting the direction of flow but does over estimate surface current speeds when validated by the radar network. Recently CARICOOS has developed a finite volume community ocean model (FVCOM) for the region that runs once a day. This model has higher spatial resolution than AMSEAS and can account for the complex flows around the tiny islands around Puerto Rico and the Virgin Islands. The surface trajectories from the FVCOM model were compared against those from the AMSEAS model as well as the HF radar output. The FVCOM model output is available from February 2020 to present. Initial findings indicate that the surface flows from the FVCOM model are overestimated. A daily validation tool was created for the AMSEAS surface current product. The skill of the AMSEAS model oscillated from an error of only 5 km to as much as 60 km after 24 hours of the virtual drifter release. Using both HFR data, AMSEAS and FVCOM model output we created several surface current maps and virtual drifter trajectories to simulate the movement of Sargassum Seaweed around Puerto Rico and the Virgin Islands. This will hopefully improve the model forecasts by providing a consistent validation source. We are working to make these products available to ecological or economic stakeholders in coastal tourism as well as the US Coast Guard for search-and- rescue.