Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen
OPUS4-12173 Wissenschaftlicher Artikel Shin, Seoleun; Sommer, Matthias; Reich, Sebastian; Névir, Peter Evaluation of three spatial discretization schemes with the Galewsky et al. test We evaluate the Hamiltonian particle methods (HPM) and the Nambu discretization applied to shallow-water equations on the sphere using the test suggested by Galewsky et al. (2004). Both simulations show excellent conservation of energy and are stable in long-term simulation. We repeat the test also using the ICOSWP scheme to compare with the two conservative spatial discretization schemes. The HPM simulation captures the main features of the reference solution, but wave 5 pattern is dominant in the simulations applied on the ICON grid with relatively low spatial resolutions. Nevertheless, agreement in statistics between the three schemes indicates their qualitatively similar behaviors in the long-term integration. 2010 10.1002/Asl.279 Institut für Mathematik
OPUS4-35783 Wissenschaftlicher Artikel Shin, Seoleun; Reich, Sebastian; Frank, Jason Hydrostatic Hamiltonian particle-mesh (HPM) methods for atmospheric modelling We develop a hydrostatic Hamiltonian particle-mesh (HPM) method for efficient long-term numerical integration of the atmosphere. In the HPM method, the hydrostatic approximation is interpreted as a holonomic constraint for the vertical position of particles. This can be viewed as defining a set of vertically buoyant horizontal meshes, with the altitude of each mesh point determined so as to satisfy the hydrostatic balance condition and with particles modelling horizontal advection between the moving meshes. We implement the method in a vertical-slice model and evaluate its performance for the simulation of idealized linear and nonlinear orographic flow in both dry and moist environments. The HPM method is able to capture the basic features of the gravity wave to a degree of accuracy comparable with that reported in the literature. The numerical solution in the moist experiment indicates that the influence of moisture on wave characteristics is represented reasonably well and the reduction of momentum flux is in good agreement with theoretical analysis. Hoboken Wiley-Blackwell 2012 12 Quarterly journal of the Royal Meteorological Society 138 666 1388 1399 10.1002/qj.982 Institut für Mathematik
OPUS4-36703 Wissenschaftlicher Artikel Shin, Seoleun; Zöller, Gert; Holschneider, Matthias; Reich, Sebastian A multigrid solver for modeling complex interseismic stress fields We develop a multigrid, multiple time stepping scheme to reduce computational efforts for calculating complex stress interactions in a strike-slip 2D planar fault for the simulation of seismicity. The key elements of the multilevel solver are separation of length scale, grid-coarsening, and hierarchy. In this study the complex stress interactions are split into two parts: the first with a small contribution is computed on a coarse level, and the rest for strong interactions is on a fine level. This partition leads to a significant reduction of the number of computations. The reduction of complexity is even enhanced by combining the multigrid with multiple time stepping. Computational efficiency is enhanced by a factor of 10 while retaining a reasonable accuracy, compared to the original full matrix-vortex multiplication. The accuracy of solution and computational efficiency depend on a given cut-off radius that splits multiplications into the two parts. The multigrid scheme is constructed in such a way that it conserves stress in the entire half-space. Oxford Elsevier 2011 8 Computers & geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology 37 8 1075 1082 10.1016/j.cageo.2010.11.011 Institut für Mathematik
OPUS4-38200 Wissenschaftlicher Artikel Grewe, Volker; Brinkop, Sabine; Joeckel, Patrick; Shin, Seoleun; Reich, Sebastian; Yserentant, Harry On the theory of mass conserving transformations for Lagrangian methods in 3D atmosphere-chemistry models Stuttgart Schweizerbart 2014 7 Meteorologische Zeitschrift 23 4 441 447 10.1127/0941-2948/2014/0552 Institut für Mathematik