Calculation of Gridded Surface Current from Observed Lagrangian Trajectories in the East Sea

Surface ocean current is crucial for enhancing the safety and efficiency of maritime logistics and transportation, boosting fisheries production and management, and supporting military operations. This study analyzed 25,342 trajectories from NOAA’s Global Drifter Program (1991–2020), 12 from KIOST, and 63 from KHOA (2015–2024). The surface drifters entering the East Sea were extracted, and a five-step quality control process was implemented. Unobserved values were removed, quality control was applied based on drogue lost, abnormally speed or stuck, unrealistic acceleration. To estimated the gridded oceanic current with high-resolution, we removed the Ekman current and tides from the observed velocity and took advantage of a simple kriging approach. The validation against existing datasets confirmed that major ocean currents exhibited similar patterns compared to absolute geostrophic current from the satellite-based altimetry. The constructed dataset is expected to contribute to the accurate identification of surface current movements and the development of realistic models that incorporate regional characteristics based on data assimilation.