Observing the Air-Sea Transition Zone Using Combined Uncrewed Systems: Feasibility and Requirement

The air-sea transition zone (the upper ocean, air-sea interface, and atmospheric marine boundary layer) represents the physical space where air-sea interaction takes place. The perspective of the air-sea transition zone (ASTZ) advances the conventional concept of air-sea interaction at the air-sea interface to include both the oceanic and atmospheric boundary layers, which responds to and influences air-sea fluxes of energy, momentum, and mass. Studying the ASTZ acquires collocated and simultaneous observations of the ocean-atmosphere profiles of the entire ASTZ and seamless coupling of the atmosphere and ocean through the ASTZ in the Earth system models. Traditionally, observing the ASTZ has been done using ships and aircraft, which are expensive and logistically difficult. The recent rapid development of autonomous observing technologies opens the door to observe the ASTZ using uncrewed underwater, surface and aerial vehicles. This proposed research intends to investigate the feasibility and requirement of using uncrewed mobile platforms to observe the ASTZ.
We propose to conduct our investigation through developing a virtual sampling framework using combined uncrewed systems (CUSs). In this framework, high-resolution coupled ocean-wave-atmosphere model simulations will be sampled by virtually deploying underwater gliders, saildrones, and aerial drones in coordination. Because the motions of the CUS components depend on wind, sea state, and current conditions, the design and navigation of their positions and tracks to be close to each other will have to be done based on past deployment experience of their motion characteristics. The virtually sampled data will be placed in the contest of the full simulations to assess the requirements to adequately represent the structure and variability of the ASTZ on various scales in real deployment of a CUS. The requirements include, but are not limited to, sampling locations, time, frequency, duration, vertical extents, horizontal coverage, etc. The virtual sampling framework will be conducted in the tropical Pacific, particularly over the eastern edge of the warm pool and the equatorial ITCZ/cold tongue region under various weather and climate conditions (e.g., phases and stages of the MJO and ENSO). This proposed study builds upon the PI team’s collective expertise in air-sea interaction using in situ and remote sensing observations and coupled ocean-atmosphere models, and experience in field observations. The most direct beneficiary of this study would be the future field campaign on Air-Sea Interaction at the Eastern Edge of the Pacific Warm Pool and Pacific Upwelling and Mixing Physics (PUMP). Results from this study will aid designs of these and other field campaigns that include observations of the ASTZ using CUSs as an objective to advance our understanding of component interactions of the Earth’s climate system and our ability of modeling and predicting climate variability to assist NOAA’s science and service mission.