The ocean surface circulation with all its time-space complexity is the open-air limb of the oceanic mass transport. Surface currents carry heat (climate), plankton (marine biology), plastic (pollution). As well wave-current interactions lead to significant sea state variability and strong wave height gradients inside relatively small geographic zones. The complex behaviour of the coupled wave-current system represents challenging risks for socio-economic activity at sea: merchant shipping, renewable energy production, oil & gas operations, fishing activities, and tourism. In addition, the intensification of sea fluxes as the result of global climate changes even complicates marine safety challenges and increases the number of risks related to unfavourable ocean. Accurate, high-resolution estimate of ocean surface currents is both a challenging issue and a growing end-user requirement. Yet, the global circulation is only indirectly monitored through satellite remote sensing; to benefit the end-user community (science, shipping, fishing, trading, insurance, offshore energy, defence), current information must be accurately constructed and validated from all relevant available resources.
The objective of the Space4SafeSea project is to develop and validate for maritime safety applications an ocean state product based on synergetic use of a new merged ocean current and surface wave data in the Great Agulhas region, an area synonymous of hazardous sea state and rogue waves due to the interaction between the wave and the current. The new merged ocean current will be derived from Altimeter data and AIS-based current using the Multiscale Inversion for Ocean Surface Topography (MIOST) variational tool. The directional spectrum of sea surface waves from SWIM will be used in conjunction with a wave-model output and swell ray propagation model.
The resulting data processing methodology and implemented algorithms will provide robust estimations for spatial distribution of complicated ship navigation zones due to sea-state conditions. An initial version of this product will be followed by evaluation and feedback from end-users who have directly experienced ground truth situations, leading to further methodology and technical development cycles to successively refine the final product output.