Turbulence and eddy regional exchange in the western North Pacific: joint oceanic and atmospheric experiment using R/V New Ocean Researcher 1

Abstract Sponsored by the National Science and Technology Council of Taiwan, the programs Sailing to the Blue Sea (SBS), Kuroshio to Turbulence Exchange (KTEX), and the U.S.-Taiwan collaboration program Island Arc Turbulent Eddy Regional Exchange (ARCTERX) jointly conducted a multidisciplinary field campaign aboard the R/V New Ocean Researcher 1 from March 25 to April 19, 2024. The cruise completed a round trip from Kaohsiung to Palau, executing coordinated oceanic and atmospheric observations in the western North Pacific. The scientific objectives of this campaign were to: (1) investigate the physical, biological, and biogeochemical properties of a targeted cyclonic mesoscale eddy in the western North Pacific and its impact on oceanic weather through air-sea interactions; (2) quantify water mass transformation and nutrient flux variability from the North Equatorial Current (NEC) to the Kuroshio; (3) examine the diurnal warm layer and its coupling with atmospheric boundary layer variability in the subtropical and tropical regions; (4) detect potential ground motion in the Philippine Sea basin at the eastern flank of the Gagua Ridge, east to Taiwan; and (5) measure along-track gravity anomaly across the Philippine Sea basin. The campaign successfully sampled a cyclonic eddy centered at (131°E, 18°N), hydrographic transects across the Kuroshio and the NEC, and high-resolution upper ocean temperature profiles in the tropical ocean. To facilitate detailed analyses of the complex cruise data, the ship-based and autonomous observations are introduced here.