Virtual Sampling of the Tropical Air-Sea Transition Zone Using Coordinated Uncrewed Systems

Exchanges of energy, mass and momentum between the atmosphere and the oceans are fundamental to the functioning of the Earth’s system on a wide range of timescales. However, they remain some of the most challenging processes to observe and model. The existing knowledge gap can be reduced by co-locating observing platforms within the Air-Sea Transition Zone (ASTZ), which consists of the upper ocean, the atmospheric marine boundary layer, and their interface. ASTZ sampling should achieve simultaneous measurements of 1) temperature, current and salinity in the upper ocean, 2) atmospheric, oceanic and surface wave properties at the air-sea interface 3) wind, temperature and moisture in the marine boundary layer. Fast-paced advances in uncrewed vehicle technology challenge us to sample across the ASTZ using a combination of available unmanned systems. In this study, we first leverage a diverse set of tools, including machine-learning, to reproduce the navigation of saildrones, gliders and air drones, accounting for the influence of various environmental factors on their motion. Uncrewed systems are then placed in high-resolution, fully-coupled atmosphere-wave-ocean numerical simulations to virtually sample the tropical ASTZ in two scenarios: 1) low-wind regime in the tropical Pacific Ocean, 2) high-wind regime within a tropical cyclone. For each regime, we will assess the success and requirements of coordinated ASTZ measurements using ensembles of missions for a set of sampling patterns of varying complexity.