Congo Wetland Water Level Changes from ALOS PALSAR InSAR

The Congo Basin is the world's third largest in size and the second in discharge, and is of great importance to local climate and hydrology. However, compared to the world's largest basin — the Amazon Basin, hydrologic characteristics of the Congo Basin remain much less known. Interferometric Synthetic Aperture Radar (InSAR) has been proven to be a successful technology to derive water level changes over wetlands with unprecedented spatial resolution and accuracy. In this study, L-band ALOS PALSAR data obtained during high water level season is used to acquire (spatially) relative water level changes over the central Congo wetlands near the confluence of the Ubangi River and the mainstem. Water level changes from Jason-2 and Envisat satellite radar altimeter measurements are combined the InSAR results to provide (spatially) absolute water level changes. Due to the lack of gauge stations in the basin, our result is assessed using surface storage change values derived from the Hillslope River Routing (HRR) model, which is constrained using historical monthly discharge data from in situ stream gauges, and total storage changes from GRACE.