PMC

Zones in the Caribbean region where distance from shore and water depth meet International Maritime Organization guidelines for ballast exchange. To exchange ballast >200 nautical miles from shore in water 200 m deep, ships must travel 280 nautical miles northeast of Haiti (A) or to the Gulf of Mexico (B). To exchange ballast at the minimum 50 nautical miles from shore in water >200 m deep, ships must travel >90 nautical miles northeast (C) or 50 nautical miles south (D) of Haiti or conduct the exchange in an area <45 nautical miles wide approximately equidistant from Haiti, Cuba, and Jamaica (E). Light blue shading indicates distance from land is <50 nautical miles and/or seawater depth is <200 m. Medium blue shading indicates distance from land is >50 nautical miles but <200 nautical miles, and seawater depth is >200 m. Dark blue shading indicates distance from land is >200 nautical miles and seawater depth is >200 m.

Signaling message exchange steps between the USV and GC.

General representation of the global carbon cycle (credit to Jack Cook, Woods Hole Oceanographic Institution). The broad translucent white arrows illustrate the general motion of the carbon cycle, depicting production and burial of carbon, and its uplift erosion and weathering resulting of return of this carbon to the atmosphere. The orange arrows highlight loci of carbon (CO2) exchange and transfer, such as via photosynthesis and respiration, including examples of human influences on carbon cycle processes. A hypothetical national boundary and exclusive economic zone (EEZ) are indicated as yellow dashed lines

Trajectory preprocessing structure. MMSI is used as the unique identification code to exchange data. ID is used to identify a single trajectory. The original points queue is used to store the trajectory points, noise points are removed at this stage. The compression path tree is used to output the simplified trajectory, redundant points are removed at this stage. The sample points queue is used to store the simplified trajectory, when a stay point is detected, a complete simplified trajectory is output for clustering. The black circle represents a new received trajectory point. The dark blue circles represent the points ready to be cleaned. The green circles represent the sample points of the simplified trajectories. The gray circles represent noise points or redundant points. The red circles represent the stay points.