Using the Surface Water and Ocean Topography Mission Data to Estimate River Bathymetry and Channel Roughness

Abstract Currently, several satellite missions capable of measuring either inundation extents or water surface elevations are operational. Measurements of water surface elevation collected by nadir altimeters have been used to calibrate hydraulic models and inundation extents derived from satellite imagery collected during or immediately after large floods have revolutionized how we assess damage and, on occasion, coordinate first response, especially in data poor regions. The upcoming Surface Water and Ocean Topography (SWOT) satellite mission will measure inundation extents and water surface elevations simultaneously and over contiguous river sections that can extend for 100 km or longer. In anticipation of the SWOT mission, researchers have developed algorithms that infer channel parameters such as roughness, cross-sectional area, and ultimately discharge using time series of long river profiles. This chapter gives an overview of the SWOT mission characteristics and measurement principle, describes the SWOT data products, and the methods used to estimate river cross-sectional area, roughness, and discharge from this novel source of data.