Amur Estuary in the Mirror of Secular Variability (1896-2021)

The Amur Liman is a unique bipolar estuarine system that functions as a hydraulic link between the Sea of Okhotsk and the Sea of Japan. Using a synthesis of long-term hydrological observations (1896–2021) and satellite remote sensing (MODIS/Terra and Aqua), this study examines the secular variability of discharge, circulation patterns, and climate-driven hydrodynamic restructuring in the Amur estuary. The analysis demonstrates that Liman dynamics are governed by the interaction between the Siberian High and the Far Eastern monsoon system, which together regulate ice regimes, seasonal runoff, and extreme flood events. Particular attention is given to tidal interference, flow bifurcation at Cape Pronge, and the formation of the so-called “Amur Loop,” highlighting the role of baroclinic effects and basin morphology in shaping circulation. Long-term discharge phase analysis reveals that extreme floods are synchronized with secular climatic signals rather than representing stochastic anomalies. These results frame the Amur Liman as a sensitive climate indicator system, with important implications for future coastal management, flood risk assessment, and regional environmental monitoring under conditions of accelerating climatic variability.