Straub, Winfried

Wissenschaftliche Berichte des Instituts für Metorologie und Klimaforschung der Universität Karlsruhe, 41, ISSN: 0179-5619, ISBN: 978-3-86644-226-9 (2008)

In the present thesis, effects of orographically induced atmospheric flow on the development of convective clouds are investigated. Based on various numerical simulations with the mesoscale atmospheric model KAMM2, especially the influences of mountain waves on the initiation and development of deep convection are analyzed. At first, highly idealized simulations of convective clouds over flat terrain are carried out to study the sensitivity of the cloud-dynamics particularly with regard to changes of different parameters such as the wind profile or the atmospheric temperature and moisture layering.Furthermore, simulations of quasi-stationary mountain-waves in atmospheric flow over two-dimensional hills and valleys are presented. For the purpose of model evaluation, these simulations are compared with analytical solutions of the linear, hydrostatic mountain-wave equation. Simulations of mountain-waves in more complex situations allow for studying some particular characteristics of CAPE and CIN in mountainous terrain. Finally, studies on the initiation and development of convective clouds in complex terrain are presented. These studies show that mountain-wave-induced changes of windspeed and stability in the atmosphere near the ground may leed to striking differences in the formation of deep convection.