Ecosystem Water Use Efficiency

Soil moisture (SM) data were obtained from the Global Land Data Assimilation System (GLDAS) in three vertical layers: 0–10 cm, 10–40 cm, and 40–100 cm. Integrated topsoil moisture across the full 1-meter profile was derived using a thickness-weighted approach. Additionally, monthly climate variables were extracted from the ERA5-Land dataset, including 2 m air temperature (Ta), solar radiation (Rs), 2 m dewpoint temperature (Te), and wind speed (WS). The vapor pressure deficit (VPD), a critical factor influencing stomatal regulation and plant water stress, was calculated from the air temperature and dewpoint temperature data.