Performance of Hybrid Eulerian-Lagrangian Semi-Implicit time integrators for nonhydrostatic mesoscale atmospheric modeling

In this thesis, the performance and accuracy of explicit, semiimplicit, and Hybrid EulerianLagrangian SemiImplicit (HELSI) timeintegration methods used in atmospheric modeling are examined. Four test cases are analyzed: A density current, an inertial gravity wave, a rising thermal bubble, and a hydrostatic mountain wave. Strict attention is paid to computational time, stability criteria, and accuracy. The project aims to show increased efficiency using the HELSI method over fully semiimplicit methods, which, in turn, should be better than the splitexplicit methods currently used in mesoscale models such as WRF, COAMPS, and the German LM model. This increase in efficiency allows for valuable computational resources to be used for other purposes, such as improved data assimilation, increased spatial resolution, or more detailed physics.