An important part of the discipline of atmospheric physics deals with atmospheric dynamics. So-called „Geophysical Hydrodynamics” is characterized by a number of special aspects and features which lead to significant challenges. In particular one has to account for numerous interactions with other physical processes (such as radiation, cloud microphysics etc.), which often cannot be represented explicitly by themselves. The multiscale nature of geophysical flows poses another significant challenge.
The group of Prof. V. Wirth focuses on the following scientific topics:
- Rossby wave trains in the upper troposphere and their implications for weather forecasts
- Dynamics of orographic banner clouds
- The extratropical tropopause region
- Formation and intensification of tropical cyclones
- Micrometeorological flow simulations in urban environments
This movie shows the evolution of a wave train in the upper troposphere (i.e. at ca. 10 km altitude) over a time span of 20 days. The plots represent the mean conditions for the meridional wind (i.e. the wind in the north-south direction, red for southerly flow, blue for northerly flow). A wave train can be seen originating over western North America on day -7. During the following days the wave train propagates across the North Atlantic reaching Europe by day 0. Subsequently it weakens while it travels across Asia.
This movie illustrates the numerical simulation of a banner cloud attached to an idealized pyramid-shaped mountain. The plots show an isosurface of cloud water content with the color representing the vertical wind. The movie indicates to what extent a banner cloud is an instationary phenomenon. On average the cloud is located mostly in the lee of the mountain.