Anticipated improvements to in-river DEMs from the Surface Water and Ocean Topography mission
Abstract
Existing publicly available digital elevation models (DEMs) provide global-scale data, but are often not precise enough for studying processes that depend on small-scale topographic features in rivers. For example, slope breaks and knickpoints in rivers can be important in understanding tectonic processes, and riffle-pool structures are important drivers of riverine ecology. More precise data (e.g. LiDAR) are available in some areas, but their spatial extent limits large-scale research. The upcoming Surface Water and Ocean Topography (SWOT) satellite mission is planned to launch in 2021 and will provide measurements of elevation and inundation extent of surface waters between 78 degrees north and south on average twice every 21 days. Here, we present a novel noise reduction method for multi-temporal river elevation profiles from SWOT that combines a truncated singular value decomposition and a slope-constrained least-squares estimator. We use simulated SWOT data of 85-145 km sections of the Po, Sacramento, and Tanana Rivers to show that 3-12 months of simulated SWOT data can produce elevation profiles with mean absolute errors of 5.38-12.55 cm at 100-200 m along-stream resolution. Mean absolute errors can be reduced further to 4-11 cm by averaging all observations together. The average profiles have errors much lower than existing DEMs, allowing new advances in riverine research globally. We consider case studies in geomorphology and ecology to show the scientific value of the more accurate in-river DEMs expected from SWOT: concavities in the simulated SWOT elevation profile of the Po river coincide with underlying faults, and locally steep sections of river profiles, observable in SWOT data, represent important habitat for benthic invertebrates.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS53C1347L
- Keywords:
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- 1845 Limnology;
- HYDROLOGYDE: 1856 River channels;
- HYDROLOGYDE: 4520 Eddies and mesoscale processes;
- OCEANOGRAPHY: PHYSICALDE: 4544 Internal and inertial waves;
- OCEANOGRAPHY: PHYSICAL