David Bjerklie (USGS, USA); Claudia Carabajal (Sigma Space Corp., USA); Alejandro Egido (University of Maryland, United States)

Both radar and laser altimetry can be utilized to monitor both water level variations and channel surface gradients for the largest river systems around the world. Here, we focus on the Yukon and Copper Rivers in Alaska. Despite their extent and complexity, few US and Canadian gauges exist across the basins. This hampers modelling and basin dynamics efforts, particularly affecting flood predictions and fisheries analysis. Both conventional (Jason-2, ENVISAT, SARAL, Jason-3) and Delay-Doppler (CRYOSAT-2, Sentinel-3A) radar altimetry, and laser altimetry (ICESat-1), offers spatially and temporally varying measurements, and multiple data sets allow for cross-validations. Innovative fully-focused SAR data processing techniques also offer improved along-track spatial resolution. Here, we examine the performance of the various instruments and techniques with a focus on river reach acquisition and improved elevation accuracy. We also discuss the merits of combining the data sets and look to their application with respect to i) the determination of river discharge and ii) isolating contributions to discharge from glacial and tundra melt waters.