Applicability of SWOT data in calibrating WRF-Hydro hydrological model over the Tawa River basin

Freshwater is considered an essential natural resource that must be monitored effectively. The Surface Water and Ocean Topography (SWOT) satellite mission scheduled for launch in December 2022 will enable river discharge estimation from surface water extents, elevations, and slopes. However, the SWOT-based discharges will be inconsistent due to infrequent temporal sampling (TS) of SWOT orbit. This study explores the potential of unique TS of SWOT to determine whether it influences the calibration of hydrological model. The Weather Research and Forecast Hydrological system (WRF-Hydro) has been used to simulate river discharge. Further WRF-Hydro model has been calibrated using proxy SWOT data based on a dynamically dimensioned search algorithm. Results show that more than 90% of parameter iterations have KGE values with less than 20% absolute percent difference when only SWOT TS alone has been considered. The results suggest that model calibration using SWOT-based discharge performs similarly to daily in-situ discharge.

Automated summary

The SWOT satellite mission, scheduled for launch in December 2022, is expected to effectively monitor freshwater resources. However, the infrequent temporal sampling of the SWOT orbit will lead to inconsistent estimation of river discharge. This study investigates the influence of unique temporal sampling on the calibration of a hydrological model, and suggests that using SWOT data for calibration can provide similar results to daily in-situ discharge measurements.