Modelling the impact of iceberg toppling on fjord stratification
Date:
Abstract: Many tidewater glaciers in Greenland terminate in deep fjords in which cold and brackish surface Polar Water lies above warmer and saltier Atlantic Water. This temperature and density stratification is thought to impact fjord circulation and glacier submarine melt rate. Large icebergs, which may be several hundred metres across, frequently calve into these fjords. After detaching from the glacier front, the calving icebergs roll over, generating large tsunami waves and stirring the water around them. To quantify the ocean mixing induced by such an event, we are developing a coupled iceberg-ocean model, treating the iceberg as a Newtonian rigid body and evolving the fluid using the lattice Boltzmann method [note from future: I am no longer using this method]. This talk discusses the initial stages of the model development, including the results of benchmark tests on buoyancy-driven fluid flow and iceberg dynamics. We note that, in addition to quantifying the ocean mixing, when completed, this model could be adapted to study the transport of sediment and biogeochemical tracers scoured from the fjord bed by a toppling iceberg.