Hydrologic Model Parameter Estimation in Ungauged Basins Using Simulated SWOT Discharge Observations

Abstract In situ gauge networks are often used in hydrologic model calibration, but these limited or nonexistent many regions. The upcoming Surface Water Ocean Topography (SWOT) mission promises to fill this observation gap by providing discharge estimates for rivers wider than 100 m. SWOT utility parameter selection regions devoid of gauges is assessed using proxy derived from an observing system simulation experiment and Monte Carlo methods. sensitivity the measurement error frequency also evaluated. Single‐ multi‐point performed ten sub‐basins within Susitna upper Tanana river basins Alaska. expected observe Alaskan points 4–7 times per 21‐day repeat cycle with 120‐km swath coverage. For 35%, estimation successful 50% (90%) single‐ (multi‐) point selection. Decreasing simulate lower latitudes resulted success only 10% midlatitude tropical single‐point selection, whereas was 80% (60%) (tropical) sub‐basins. Single‐point more sensitive results strongly support use over yielding robust nearly independent frequency. Most importantly, study suggests can be successfully select parameters without network.