Oceanography: Sea flow structures could aid search and rescue operations

The identification of flow structures in the ocean, which attract floating objects, could help optimize search and rescue operations for people lost at sea suggests a Nature Communications paper.

Current search and rescue operations use models combining sea dynamics, weather prediction and on site observations to produce a probability map predicting a person’s location. However, uncertainty over where the person entered the water and a lack of observational data about how ocean currents evolve over time makes it more difficult to predict a location as time goes on.

Using sea-surface data, Mattia Serra, George Haller and colleagues at various US institutions predicted the existence of TRansient Attracting Profiles (TRAPs), which govern short-term trajectories in ocean currents and reveal regions of accumulation of objects floating on the sea surface. To verify the findings, the authors conducted three field experiments to simulate search and rescue situations in the ocean south of Martha’s Vineyard in Massachusetts, USA. Here, they deployed a series of manikins and floating devices to mimic cases where people had fallen in the water, and sought to determine if TRAPs could be used to predict their location. The authors demonstrated that TRAPs could be calculated using measured as well as modelled ocean current velocities, and that they can help predict the most likely locations of the objects two to three hours after their disappearance.

The authors conclude that TRAPs could help enhance existing search and rescue techniques and inform hazard responses to environmental disasters, such as oil spills.