WP4: Impact of ABL Heterogeneity/Troposphere Coupling on Convection

Convection initiation and evolution partially result from the subtle interplay between local variations in convection-related parameters with ABL and mid-tropospheric conditions and flow. These variations may originate from horizontal surface flux gradients caused by for instance land use and/or root zone soil moisture gradients and the orography. A key role in the process chain from land-surface variations, ABL heterogeneity and convection is played by ABL-troposphere coupling – a process which occurs on different scales.

In this work will provide a better understanding of this coupling, which is important for a better estimation of the occurrence and strength of convection and its influence on heavy precipitation events. This includes the quantification of ABL troposphere coupling and the connection between coupling and regions of convection initiation and intensity.

The figure is showing flashes over Germany and joining areas for April to September 2007. This gives an indication of hot spot regions of convection and will help to choose areas of investigation.

In our work we will answer the following questions:

• How can we quantify the ABL-mid-troposphere coupling in ICON-LES?
• How important is an adequate representation of land surface heterogeneity to simulate this coupling?
• What is the impact of model resolution on simulating the coupling?