Revealing lake dynamics across the Amur River Basin over the past two decades using multi-source remote sensing datasets

Study region: The Amur River Basin (ARB), a transboundary river basin comprising four sub-regions: the Northeast Plain of China, Mongolian Plateau, Siberian Federal region and Far East Federal region. Study focus: This research presents a comprehensive analysis on the lake dynamics in both lake area and number across the entire ARB from 1999 to 2021, using multi-source remote sensing datasets. The driving mechanisms are analyzed, considering the gradients in climatic conditions and varying levels of anthropogenic activities in different sub-regions. New hydrological insights for the region: The study found that both the total area and number of lakes in ARB decreased before 2009, whereafter increased significantly until 2021. Specifically, lakes in the Mongolian Plateau shrank seriously (-46.6 km2 yr−1), while those in the Northeast Plain of China, Siberian Federal region, and Far Eastern Federal region all showed overall expanding trends. Lake changes in the entire ARB were predominantly influenced by precipitation (R2:0.54,) and soil moisture (R2:0.55). Increasing irrigation and grazing were the main forces in the Mongolian Plateau, while hydro-climatic factors played more important roles in Northeast Plain, Siberian Federal region, and Far Eastern Federal region. This study provides a comprehensive cross-regional analysis of lake area changes and driving forces, which is of great value in ensuring lake ecological safety in ARB and other regions with densely distributed lakes.