<scp>Model‐coupled GRACE‐based</scp> analysis of hydrological dynamics of drying Lake Urmia and its basin

Lake Urmia Basin (LUB), in northwestern Iran, is under the influence of extreme degradation due to a number natural and anthropogenic factors. The existence critical for microclimate region as well quality human life wildlife, which necessitates an up-to-date holistic analysis its hydrological dynamics. In this premise, satellite-based Terrestrial Water Storage (TWS) received from GRACE mission was coupled with hydrometeorological modeling assessment tools analyze status lake basin. As new gap-filling approach, Seasonal-Trend decomposition using Locally estimated scatterplot smoothing (LOESS) (STL) technique proposed study reconstruct missing TWS data. Integrating satellite precipitation data Catchment Land Surface Model (CLSM) WaterGAP model outputs, investigated. STL-based turned out concord simulated CLSM indicating acceptable performance technique. findings revealed that LUB had undergone alarming situation 2003 2021 total loss 10 km3 7.56 groundwater storage (GWS), respectively. water level time series also indicated diminished annual rate −70 ± 21 cm/yr corresponding depletion about 13.35 3.9 m during 2003-2021 period. GRACE-derived GWS agreed simulations. Assessment events suggested basin suffered severe dry event 2008 resulting level. It found onward, setting dominated negative balance −0.96 km3.