Operational Modeling of Surfing Transport for Buoyant Objects in OpenDrift

Surfing transport occurs when a buoyant object is caught on the face of a breaking wave and travels with the breaking wave. Surfing transport can affect the transport of marine debris, plastics, search and rescue objects, among other objects of interest. Operational trajectory models, such as OpenDrift, allow users to quickly predict where an object will go or where it came from as it drifts in the ocean. These tools are useful for predicting where plastics or oil will go after a spill so effective cleaning efforts can be launched along with effective search patterns deployed for search and rescue objects. The OpenDrift model is a lightweight, highly modular, Python-based modeling framework used to predict the trajectory of a wide variety of objects in the ocean. The model is object-oriented, where the Python objects represent a model class that can be configured based on a desired set of transport physics and object characteristics. A surfing transport function is added to the set of physics methods based on observations of surfing transport made using small drifters in the nearshore. Including surfing transport has been shown to increase the accuracy of the trajectory modeling for small buoyant plastics in the nearshore. The additional functionality is also expanded for use in deep water but has not yet been validated against similar observations.