Warming response of convective rainfall under different synoptic forcings

Extreme precipitation events in central Europe during the summer months are typically associated with intense convection. In this study, we perform Lagrangian analysis of convective cells under different large-scale circulation regimes. Precipitation is commonly analysed from an Eulerian perspective, in which rainfall is considered at a fixed location. Lagrangian analysis of precipitation represents an alternative approach: precipitation objects are identified in a precipitation field and are tracked through space and time, allowing object properties over the lifecycle of a convective cell to be computed. This approach offers additional insights into the mechanisms by which convective cells develop, behave across their lifecycle, and how these may respond to warming.

Here we analyse convection-permitting simulations with the COSMO-CLM at 3-km resolution over central Europe. Precipitation objects are tracked through space and time, collecting cell characteristics for each object, e.g. cell area, intensity, distance travelled, etc. Convective cells are identified using an objective algorithm. These are are then categorized based on their accompanying synoptic-scale circulation patterns using a physically based objective classification method. Cell properties – as well as how these respond to warming – are then compared between the different categories, offering insight into the impact of the large scale circulation on the response of convective precipitation – both mean and extreme – and the associated cell characteristics to warming.