Projectdetails

Sediment Supply to the Arctic coastal zone

Changes in the polar system due to changing global climate are both rapid and dramatic. Polar change has been selected as one of the main themes of the International Polar Year 2007-2008. Changing Northern Hemisphere temperatures, thinning of the sea-ice, and melting of the glaciers have all been recently reported. The main research question of this proposal is how the sediment supply to the Arctic coastal system is influenced by the changing climate. Accurate understanding of the effects of climate change on river sediment fluxes is needed to predict changes in the biological productivity of the Arctic coastal ecosystem, which is extremely vulnerable to changes in sediment and associated nutrient supply.

The responses are complex; will increased glacier melting and increasing precipitation result in increased water and sediment discharge? Or will the decrease of glacier area result in decreased sediment production? Does the sediment transport capacity of the river systems decrease with decreasing glacial meltwater? And how much sediment is stored in the glacio-fluvial floodplains and long does it lag in the basin before it reaches the coast? We need to unravel these complexities in the direction and timing of the system responses to perturbations, only then can we make predictions of the sediment and nutrient supply to the ocean. The objective of this research is to describe the interacting forcing factors and responses in a numerical model.

Our existing numerical sediment transport model will be advanced to deal with two critical issues. Firstly, innovative algorithms will have to be developed to link glaciological physical parameters to sediment production. Glacial sediment production can be linked to to glacier dimensions and basal sliding speeds. Subsequently, these process descriptions can be incorporated as a module into our climate-driven sediment flux model, Hydrotrend, which models the river sediment flux as a function of total drainage basin area, basin relief, precipitation, temperature, vegetation and groundwater balance. Secondly, the presently 1D model will be enhanced into a spatially-distributed model, i.e. a grid-based model. This will allow sediment storage in the glacial and fluvial domain. Lag-time of sediment supply will inherently follow when the sediment transport capacity is reduced.

To validate our model field observation in Arctic river systems are of vital importance. We selected two end-member systems bordering Baffin Bay. Kangerlussuaq river system drains the active Greenland Ice Cap. This system is the base-case for model validation of short-term climate changes and effects on glacier and sedimentary system. Data on the forcing factors and water and sediment fluxes will be collected in the first IPY field season in 2007. To get an understanding of the longer-term response we will study McBeth river system on Baffin Island. McBeth river is decoupled from the last remnant of the Laurentide Ice Sheet, the Barnes Ice cap and allows a source-to-sink sediment supply reconstruction since the last deglaciation.

The overarching goal of the modeling framework is to ingest state-of-the-art topographical, climatological and glaciological data or modeling results as input and to predict the water and sediment fluxes in an arbitrary Arctic river basin. The potential effects of the future melting of the Greenland Ice Cap on the sediment flux to the Arctic coastal ecosystem can then be assessed.

Artikelen

• (2007). The deglaciation of Clyde Inlet, northeastern Baffin Island, Arctic Canada. Journal of Quaternary Science. pp. 3, 223-232
• (2007). Hoe beïnvloeden klimaatsveranderingen het sediment in rivieren?. Contact. pp. 24-25
• (2008). Valley filling during deglacation: a case study of clyde fjordhead, Baffin Island, Arctic Canada. . Sedimentary Geology. pp. 

Bijdragen aan boeken

• (2007). . in: Delftse geologen voorspellen de toekomst van smeltende gletsjers. : . pp. 2