Long‐Term Lake Ice Evolution in a Large Endorheic Lake Undergoing Accelerated Shrinkage in a Semiarid Region of China

Abstract Long‐term lake ice evolution under climate change has attracted global attention. However, despite the widespread occurrence of lake shrinkage in endorheic regions worldwide, few studies have explicitly addressed its effects on lake ice regimes. This study fills this research gap by investigating the long‐term evolution of lake ice in Lake Daihai—a large shrinking endorheic lake in China—by integrating six decades (1960–2022) of hydrometeorological data, retrieved Landsat images, and experiments with a three‐dimensional hydrodynamics‐ice numerical model. Our results show that Lake Daihai experienced accelerated shrinkage at an average rate of −2.18 km 2 yr −1 from 1960 to 2022, which was primarily driven by intensified anthropogenic activities and increased evaporation. Concurrently, the annual average lake ice thickness exhibited an accelerated decreasing trend at an average rate of −0.39 cm yr −1 . This ice‐thinning trend was attributed to the processes of atmospheric warming (air temperature increase: 2.5°C), salinization (increase in salinity: 451.3%), and morphological changes associated with lake shrinkage (water depth reduction: −12 m; surface area reduction: −72.9%). Model experiments reveal3ed that the representative factors (i.e., air temperature, salinity, and average water depth) of these processes were significantly correlated with ice phenology metrics (i.e., ice‐on date, ice‐off date, and ice duration); their relative contributions to ice thinning were 36.1%, 18.9%, and −15.2%, respectively, and the wind speed contributed 3.5%. Ice thinning was driven mainly by atmospheric warming but slowed by lake shrinkage characterized by a decrease in the average water depth. Under ongoing global warming, ice‐thinning is projected to accelerate by 2031 because of the nonlinear increase in the contribution of salinization in this shrinking lake. These findings highlight that traditional climate‐centric models may underestimate or overestimate lake ice dynamics if they fail to account for salinization or morphological changes, underscoring the necessity of developing integrated assessment frameworks tailored to shrinking endorheic lakes.