Challenging SWOT: Early Assessment of Level 2 High-Rate River Products in an Urbanized, Low Elevation Coastal Zone

The surface water and ocean topography (SWOT) mission offers groundbreaking opportunities to observe fine-scale spatial changes in low elevation coastal zones (LECZs). This study explores the first SWOT data in one of the mission’s most challenging environments: a data-scarce, tropical region with flat topography, heavy urbanization, and a river with a weak, tidally influenced slope. We focus on SWOT’s water surface elevation (WSE) and water surface slope (WSS) products at the reach level, comparing the measurements to in situ data. Our analysis shows that about half of SWOT’s WSE and WSS measurements fall within the desired error budgets, though WSS lacks linear correlation with in situ data. At this early stage, both SWOT’s WSE and WSS require validation in such complex areas. However, as SWOT’s high-resolution observations improve over time and are integrated with other data, they are expected to provide valuable insights into dynamic river and estuarine processes.