BSc/MSc projects

• Effect of debris cover on glacier dynamics
  (Level: Bachelor/Masters, Contact: Christoph Mayer, christoph.mayer@keg.badw.de)

Debris cover affects the surface energy balance of glaciers, because debris either increases ice melt due to effective thermal conductivity, or inhibits melt by shielding the ice from solar radiation. However, this change in surface mass balance also has consequences on the dynamic state of the glacier, because variations in ice loss affect the geometry of the glacier itself. As debris is continuously evacuated from glacier ice, the debris distribution on the glacier surface is always in a transient state. This implies that debris covered glaciers are never able to reach a steady state, but are in a continuous adaptation state. We aim on investigating this system with a full-Stokes ice dynamic flow-line model (Elmer-Ice) by implementing the appropriate boundary conditions and run a series of different configurations in order to see the effect of debris on the ice-dynamic conditions. The numerical model is already established and the task of the candidate will be to implement a (already existing) melt model for debris covered ice. Then different set-ups of boundary conditions should be tested in order to cover the parameter space and investigate the potential transient glacier reactions. The results are highly relevant for region wide glacier studies, as these are at the moment based on steady state assumptions.

• Calculation of ray-theoretical arrival times of seismic body waves in mantle convection models
  (Level: Bachelor; Contact: Schuberth/Freissler)

Seismological observations represent the largest dataset used to constrain present-day mantle structure. The arrival times of direct body-waves play an important role, as they have been measured (i.e., picked) for many decades now using millions of seismic recordings of many thousands of earthquakes. The picked arrival times represent the ray-theoretical traveltimes of the waves according to Fermat's principle and they have been used in many tomographic inversions for mantle structure. Alternatively, one can use them to assess mantle models derived from dynamic flow calculations. In this project, the available seismic datasets should be used to test existing mantle circulation models. To this end, the seismic observations need to be collected from the relevant data centers. In addition, ray-tracing through the geodynamic model will be performed for as many earthquakes as possible to obtain an equivalent synthetic dataset for comparison to the observations.

• Comparison of seismograms for synthetic 1-D Earth models
  (Level: Bachelor/Masters; Contact: Schuberth)

Today, a variety of numerical techniques exists to compute full waveform seismograms for 1-D Earth structures on a global scale. Three leading software packages in this regard are SPECFEM, YSPEC and AxiSEM that all follow rather different approaches. As a consequence, there are significant differences in computational requirements. In case of special setups (e.g., huge numbers of seismograms for each earthquake) it is not clear upfront, which of the methods will be best suited. The project will concentrate on comparing the results of the three methods in terms of similarity of the waveforms as well as in terms of memory and runtime requirements.

• Earth's heat budget
  (Level: Bachelor/Masters; Contact: Schuberth)

Determining the Earth's heat budget and heat production is critical for understanding plate tectonics, mantle convection and the thermal evolution of the Earth. The main possible sources of heat inside the Earth are well understood: radiogenic heat in the crust, mantle and possibly the core and secular cooling of the core and mantle. However, their relative importance is highly unknown and still debated, due to the lack of primary observations. Moreover, the total surface heat flux is not very well known, with recent estimates ranging between 40 and 50 TW. Different assumptions lead to different dynamic regimes for both present-day and past Earth's convection. This thesis project aims at exploring different scenarios of Earth's heat budget.