A Global Implementation of Single? and Dual?Source Surface Energy Balance Models for Estimating Actual Evapotranspiration at 30?m Resolution Using Google Earth Engine

Evapotranspiration (ET) provides a robust connection between hydrological cycles and surface energy balance. Accurate near-daily ET estimation has utility in water resources, agricultural management applications, crop yields drought monitoring. This study describes the implementation of an modeling system based on Priestley-Taylor version Two-Source (soil vegetation) Energy Balance Model (TSEB-PT) within Google Earth Engine environment. TSEB-PT performance was compared with simpler single-source HSEB (Hybrid Surface Balance) model to assess relative advantages disadvantages for operational application. Results were evaluated across multiple biomes climatic zones US, Europe, Australia comparison eddy covariance data from 30 flux tower sites. Both models produced similar results when considering all at daily, weekly, monthly timescales. Daily metrics sites combined yielded comparable both models, slightly lower root-mean-square error (HSEB) 1.2 (1.3) mm/d higher correlation (r) 0.83 (0.80), but larger mean percent bias (MPBE = ?9%) than 1%). lowest warm summer humid continental hot semi-arid climates evergreen broadleaf forest cover, while showed tropical savanna covers. improved cropland non-cropland estimates through simple averaging due cancellation opposing errors, showing promise as potential tools resource global scale.