Extreme convective rainfall events: response of intensity and spatial characteristics to a warmer atmosphere.(Speaker: Kai Lochbihler (KNMI))

Speaker: Kai Lochbihler, R&D Weather and Climate Modelling, KNMI

History shows that extreme convective rainfall events can have disastrous effects on our environment - societies, infrastructure and nature. Some possible impacts are flash floods, soil erosion and landslides. Thus, it is of great relevance to investigate how these events will change with a warming atmosphere.

Research has shown that precipitation amounts globally increase with a warming atmosphere. However, in the past decades it has become evident that short-term rainfall extremes can increase at an even higher rate. Typically, these convective precipitation events take place on the hourly time scale or even shorter intervals and their spatial extent ranges from a few to some tens of kilometers. These aspects challenge the applicability of conventional point-based observations and climate models as tools to study convective precipitation events. In order to investigate how short-term intensities and spatial characteristics of convective rainfall extremes change with a warming atmosphere other data sources must be used.

 In this talk I will present results based on RADAR observations and idealized simulations at sub-kilometer resolution. More specifically, I will show how spatial properties and intensities of convective extremes respond under warmer conditions, and which role the process of convective organization plays in this context.