A daily three-dimensional dataset of the Kuroshio axis and boundaries in the East China Sea and Luzon Strait

The Kuroshio, a major western boundary current in the North Pacific, critically influences regional climate, ocean circulation, and marine ecosystems across the East China Sea (ECS) and Luzon Strait. Despite its importance, long-term, three-dimensional characterizations of its variability remain sparse. Here, we present a daily-resolved three-dimensional dataset spanning 1993-2024 that quantifies the position of the Kuroshio axis and its lateral boundaries throughout the ECS-Luzon Strait system. Using the GLORYS12V1 ocean reanalysis product, we developed a streamline-constrained maximum velocity method that combines streamline continuity with local velocity maxima to robustly identify the Kuroshio axis and boundaries across 30 vertical layers, effectively reducing interference from branching currents and mesoscale eddies. Validation against prior studies and observational data confirms that the dataset accurately reproduces both surface and subsurface Kuroshio structures, captures seasonal variability, and aligns well with subsurface flow cores at key latitudes. This high-resolution, multi-year dataset offers a valuable resource for studies of Kuroshio dynamics, heat transport, interactions with mesoscale processes and the atmosphere, and related ecological and engineering applications.