10‐Year Changes in Oceanic Mesoscale Eddies in Northeast Asia Using the Coupling of GOCI and Satellite Altimetry Data

Abstract

This study addresses the limitations of traditional polar‐orbiting satellite data in terms of insufficient spatiotemporal sampling by leveraging the unique advantages of the Geostationary Ocean Color Imager (GOCI) in terms of high spatiotemporal resolution. Coupled with Archiving Validation and Interpretation of Satellite Oceanography eddy trajectory data, we established an eddy‐chlorophyll (CHL) data set (2011–2021) for Northeast Asian (NEA) seas. Through composite analysis and standardized lifetime tracking, this study systematically reveals the spatial distribution characteristics of CHL within mesoscale eddies and their evolution throughout the eddy lifetime. The results show that anticyclonic (cyclonic) Eddies A(C)Es weaken (enhance) the internal CHL concentration distribution. During the normalized lifetime, the correlation between the radius and rotational speed increases with increasing parameter values. The relative oscillation amplitude (ROA) was introduced to overcome regional background differences. The results show that the ROA of the anticyclonic eddies (AEs) (3.36) is significantly greater than that of the cyclonic eddies (CEs) (1.01). Regional decomposition indicates that this signal is driven primarily by AEs in the oligotrophic Northwest Pacific (NWP) subtropical gyre region, whereas the Sea of Japan (JS) mainly modulates the CHL variation in CEs. The anomalous CHL enhancement in NWP AEs may be jointly driven by winter mixing and phytoplankton photoacclimation mechanisms. These findings demonstrate the unique value of geostationary ocean color observations for understanding mesoscale eddy biophysics and their strong regional dependence.