Group Leader: Marco Giorgetta
Waves play an important role in the atmospheric dynamics. They can propagate from source regions over considerable horizontal or vertical distances until they are dissipated by damping mechanisms. Where the damping happens, the heat and momentum fluxes carried by the waves modifies the circulation. Examples of wave driven circulations are mid-latitude jets and the quasi-biennial oscillation (QBO) in the tropical stratosphere, and the polar night jets are strongly influenced by gravity waves emitted from the troposphere below. Our group is interested in such wave effects on the atmospheric circulation, with the current research focused on the QBO.
The QBO consists of downward propagating westerly and easterly jets which result form the interaction with an upward propagating wave spectrum, for which deep convection in the tropics is the primary source. The QBO can also modulate the wind shear and stability of the tropical tropopause layer with effects on the deep convection. We are interested in both problems, the details of the wave meanflow interaction producing the QBO, and the mechanism by which the QBO affects deep convection.
The research in our group is linked to the work of the Cloud and Convection group, due to the role of convection as the main wave source, and to the Global Circulation and Climate group working on the thermodynamic drivers of the global circulation, in which the QBO – convection system is embedded.
The research is organized along two lines, which both will make use of high resolution simulations permitting the explicit simulation of deep convection: