Modeling Suspended Sediment Concentration and Transport, Mittivakkat Glacier, Southeast Greenland
Robert S. Fausto, Sebastian H. Mernild, Bent Hasholt, Andreas P. Ahlstrøm, and Niels T. Knudsen
Suspended sediment concentration and transport is modeled for the Mittivakkat Glacier located on Ammassalik Island, Southeast Greenland, using a numerical sediment model based on lumped-elements. Empirical equations calculate sediment erosion and deposition within a constant idealized glacier drainage system. The sediment model is forced by observations and an energy balance model based on meteorological observations that provide a simulated Surface Melt and liquid Precipitation available for supra-, en-, sub-, and proglacial flow processes after vertical percolation and potential storage within the snowpack (henceforth SMP) from the glacier surface which is available for subglacial erosion, glacio-fluvial transport, and deposition within the drainage system. The idealized drainage system is constrained following the descriptions and conclusions from previous work. A model simulation run for summer 2005 shows that the cumulative modeled suspended sediment transport lies within 3% when compared with observations. Model results show that the temporal changes in the calculated suspended sediment concentrations vary over the melt season in some agreement with measured field data for the summer of 2005. Forcing the sediment model gives a correlation coefficient of 0.89 using observed proglacial meltwater discharge values and the correlation coefficient is 0.63 using modeled supraglacial meltwater runoff. The sediment model successfully captures the observed concentration and transport of suspended sediment which indicates a sufficient sediment reservoir available for transport through the idealized drainage system.