SWOT Discharge Accuracy Benchmarked in South America

Jover L.; Getirana A.; Gleason C.; An H.; Crisanti S.; Dose E.; Eylander J.B.; Hellwig I.; Lavado W.; Martinez J.-M.; Lozano J.L.S.; Santini W.; Sosa M.; Lakshmi V. · Geophysical Research Letters (2026) · DOI: 10.1029/2026gl122871

Resumen

The Surface Water and Ocean Topography (SWOT) satellite mission offers unprecedented estimates of global river discharge. This study provides a first continental-scale assessment of SWOT Consensus discharge performance across South America and compares it with a large-scale hydrodynamic model and in situ observations. Consensus generally exhibits higher skill with a median Kling-Gupta Efficiency (0.43) across the 569 benchmarked reaches. Performance varies systematically with physiographic settings. Random Forest and Spearman correlation analyses identify slope and distance to outlet as the top-ranked controls among the variables tested, though no single variable explains performance, reflecting its multi-dimensional nature. Consensus discharge inherits systematic bias from its machine learning prior, and substantial unexplained variability highlights that further work is needed to fully diagnose low-skill reaches.