Clouds and Convection (Hans Ertel Research Group)

Group Leaders: Cathy Hohenegger and Opens window for sending emailDaniel Klocke (DWD)

Shallow and deep convective clouds are an important constituent of the atmosphere. Depending on the state of the land surface and of the atmosphere they may form, grow, precipitate, decay and die. Sometimes isolated, sometimes organized in large clusters, they can take various forms and produce beautiful patterns on satellite imagery. More importantly, convective clouds not only respond to the environmental conditions but also significantly affect their surrounding, for instance through the formation and subsequent evaporation of precipitation. Allowing for a range of complex interactions among various processes and across scales, convective clouds continue to challenge our understanding.

Shallow and deep convective clouds, in particular precipitating ones, are the focus of our research. We study both the processes that control the lifecycle of convective clouds as well as the importance of small-scale convective features for the large-scale circulation of the atmosphere and the climate system. We are particularly interested in problems related to the organization of convection  and to the interactions between the land surface and convection. These problems are addressed with the following three research questions in mind:

  • What is important for convection?
  • What is convection important for?
  • How to parameterize convection?

We approach the convection problem from the small scale and make up our way to larger scales. We routinely employ large-eddy simulations (LES) with resolution O(100 m) that allow an explicit representation of convective processes and provide detailed information on the convective lifecycle. Such simulations are complemented with simulations performed at convection-permitting O(1-10 km) and coarser resolution O(> 10 km), the latter using parameterized convection. To understand whether small-scale features are nothing more than embroidery on large-scale circulations that drive the climate system, we push the use of LES and convection-permitting simulations on large domains and long timescales, see an example here. Besides this, we often use idealized approaches to develop our theoretical understanding, before testing the developed ideas in more realistic set-ups and against observations.

A list of ongoing as well as recent research topic can be found on the research page. Or by browsing the individual webpage of the group members.

The Hans Ertel research group on clouds and convection is supported by the Max Planck Institute for Meteorology and by the German Weather Service through the  Hans Ertel Centre for Weather Research.