Weismüller, Jens (2016): Entwicklung und Anwendung von HochleistungsSoftware für Mantelkonvektionssimulationen. Dissertation, LMU München: Faculty of Geosciences 

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Abstract
The Earth mantle convects on a global scale, coupling the stress field at every point to every other location at an instant. This way, any change in the buoyancy field has an immediate impact on the convection patterns worldwide. At the same time, mantle convection couples to processes at scales of a few kilometers or even a few hundred meters. Dynamic topography and the geoid are examples of such smallscale expressions of mantle convection. Also, the depth of phase transitions varies locally, with strong influences on the buoyancy, and thus the global stress field. In order to understand these processes dynamically it is essential to resolve the whole mantle at very high numerical resolutions. At the same time, geodynamicists are trying to answer new questions with their models, for example about the rheology of the mantle, which is most likely highly nonlinear. Also, due to the extremely long timescales we cannot observe past mantle states, which calls for simulations backwards in time. All these issues lead to an extreme demand in computing power. To cater to those needs, the physical models of the mantle have to be matched with efficient solvers and fast algorithms, such that we can efficiently exploit the enormous computing power of current and future high performance systems. Here, we first give an extensive overview over the physical models and introduce some numerical concepts to solve the equations. We present a new twodimensional software as a testbed and elaborate on the implications of realistic mineralogic models for efficient mantle convection simulations. We find that phase transitions present a major challenge and suggest some procedures to incorporate them into mantle convection modeling. Then we give an introduction to the highperformance mantle convection prototype HHG, a multigridbased software framework that scales to some of the fastest computers currently available. We adapt this framework to a spherical geometry and present first application examples to answer geodynamic questions. In particular, we show that a very thin and very weak asthenosphere is dynamically plausible and consistent with direct and indirect geological observations.
Abstract
Englische Übersetzung des Titels: Development and application of high performance software for mantle convection modeling
Item Type:  Thesis (Dissertation, LMU Munich) 

Subjects:  500 Natural sciences and mathematics 500 Natural sciences and mathematics > 550 Earth sciences 
Faculties:  Faculty of Geosciences 
Language:  German 
Date of oral examination:  8. February 2016 
1. Referee:  Bunge, HansPeter 
MD5 Checksum of the PDFfile:  2e5d5f39ed70a3de2ce258f4e49a13bc 
Signature of the printed copy:  0001/UMC 23583 
ID Code:  19152 
Deposited On:  24. Feb 2016 10:34 
Last Modified:  11. Apr 2016 09:57 