A Global and Spatially Distributed Model of Suspended Sediment Yield at 30 Arc Second Resolution
Abstract
Rivers connect hillslope sediment production with sedimentary basins, depositing and re-entraining grains along their course across the continents. This process holds important consequences across disciplines including the sustainability of human agriculture, the continued utility of engineered structures, and the rate of continental landscape evolution over geologic timescales. Understanding future changes in sediment load downstream requires knowledge of the dynamic processes operating upstream. Here, we use a source-to-sink numerical model at 30 arc second global resolution to connect sediment detachment on hillslopes to fluvial transport pathways and ultimately to depozones. A detachment rate is calculated monthly in every pixel as an empirical function of temperature, precipitation, vegetation cover, and local topography. A transport algorithm then routes sediment downstream according to a modified Rouse number transport criterion, wherein each of 19 logarithmically spaced grain size bins are routed independently. The model code is written in C and utilizes OpenMP parallelization routines. Calibration is performed on the University of Arizona high performance computing cluster. The calibrated model reproduces the pre-industrial suspended sediment yield of 128 global rivers with a Pearson correlation coefficient of 0.82 using just two free parameters. This model can be applied to any large river globally to estimate suspended sediment yield and project future changes. Extensions of this work will incorporate probabilistic discharge hydrology into the fluvial routing component of the model, allowing for the modeling of bed load transport.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMEP21D2292P
- Keywords:
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- 1815 Erosion;
- HYDROLOGYDE: 1820 Floodplain dynamics;
- HYDROLOGYDE: 1825 Geomorphology: fluvial;
- HYDROLOGYDE: 1862 Sediment transport;
- HYDROLOGY